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Sample records for atrazine pc code

  1. HOTSPOT Health Physics codes for the PC

    Energy Technology Data Exchange (ETDEWEB)

    Homann, S.G.

    1994-03-01

    The HOTSPOT Health Physics codes were created to provide Health Physics personnel with a fast, field-portable calculation tool for evaluating accidents involving radioactive materials. HOTSPOT codes are a first-order approximation of the radiation effects associated with the atmospheric release of radioactive materials. HOTSPOT programs are reasonably accurate for a timely initial assessment. More importantly, HOTSPOT codes produce a consistent output for the same input assumptions and minimize the probability of errors associated with reading a graph incorrectly or scaling a universal nomogram during an emergency. The HOTSPOT codes are designed for short-term (less than 24 hours) release durations. Users requiring radiological release consequences for release scenarios over a longer time period, e.g., annual windrose data, are directed to such long-term models as CAPP88-PC (Parks, 1992). Users requiring more sophisticated modeling capabilities, e.g., complex terrain; multi-location real-time wind field data; etc., are directed to such capabilities as the Department of Energy`s ARAC computer codes (Sullivan, 1993). Four general programs -- Plume, Explosion, Fire, and Resuspension -- calculate a downwind assessment following the release of radioactive material resulting from a continuous or puff release, explosive release, fuel fire, or an area contamination event. Other programs deal with the release of plutonium, uranium, and tritium to expedite an initial assessment of accidents involving nuclear weapons. Additional programs estimate the dose commitment from the inhalation of any one of the radionuclides listed in the database of radionuclides; calibrate a radiation survey instrument for ground-survey measurements; and screen plutonium uptake in the lung (see FIDLER Calibration and LUNG Screening sections).

  2. VENTURE/PC manual: A multidimensional multigroup neutron diffusion code system

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, A.; Huria, H.C.; Cho, K.W. (Cincinnati Univ., OH (United States))

    1991-12-01

    VENTURE/PC is a recompilation of part of the Oak Ridge BOLD VENTURE code system, which will operate on an IBM PC or compatible computer. Neutron diffusion theory solutions are obtained for multidimensional, multigroup problems. This manual contains information associated with operating the code system. The purpose of the various modules used in the code system, and the input for these modules are discussed. The PC code structure is also given. Version 2 included several enhancements not given in the original version of the code. In particular, flux iterations can be done in core rather than by reading and writing to disk, for problems which allow sufficient memory for such in-core iterations. This speeds up the iteration process. Version 3 does not include any of the special processors used in the previous versions. These special processors utilized formatted input for various elements of the code system. All such input data is now entered through the Input Processor, which produces standard interface files for the various modules in the code system. In addition, a Standard Interface File Handbook is included in the documentation which is distributed with the code, to assist in developing the input for the Input Processor.

  3. VENTURE/PC manual: A multidimensional multigroup neutron diffusion code system. Version 3

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, A.; Huria, H.C.; Cho, K.W. [Cincinnati Univ., OH (United States)

    1991-12-01

    VENTURE/PC is a recompilation of part of the Oak Ridge BOLD VENTURE code system, which will operate on an IBM PC or compatible computer. Neutron diffusion theory solutions are obtained for multidimensional, multigroup problems. This manual contains information associated with operating the code system. The purpose of the various modules used in the code system, and the input for these modules are discussed. The PC code structure is also given. Version 2 included several enhancements not given in the original version of the code. In particular, flux iterations can be done in core rather than by reading and writing to disk, for problems which allow sufficient memory for such in-core iterations. This speeds up the iteration process. Version 3 does not include any of the special processors used in the previous versions. These special processors utilized formatted input for various elements of the code system. All such input data is now entered through the Input Processor, which produces standard interface files for the various modules in the code system. In addition, a Standard Interface File Handbook is included in the documentation which is distributed with the code, to assist in developing the input for the Input Processor.

  4. Vectorial Resilient PC(l) of Order k Boolean Functions from AG-Codes

    Institute of Scientific and Technical Information of China (English)

    Hao CHEN; Liang MA; Jianhua LI

    2011-01-01

    Propagation criteria and resiliency of vectorial Boolean functions are important for cryptographic purpose (see [1- 4, 7, 8, 10, 11, 16]). Kurosawa, Stoh [8] and Carlet [1]gave a construction of Boolean functions satisfying PC(l) of order k from binary linear or nonlinear codes. In this paper, the algebraic-geometric codes over GF(2m) are used to modify the Carlet and Kurosawa-Satoh's construction for giving vectorial resilient Boolean functions satisfying PC(l) of order k criterion. This new construction is compared with previously known results.

  5. Identification and functional characterization of G6PC2 coding variants influencing glycemic traits define an effector transcript at the G6PC2-ABCB11 locus.

    Directory of Open Access Journals (Sweden)

    Anubha Mahajan

    2015-01-01

    Full Text Available Genome wide association studies (GWAS for fasting glucose (FG and insulin (FI have identified common variant signals which explain 4.8% and 1.2% of trait variance, respectively. It is hypothesized that low-frequency and rare variants could contribute substantially to unexplained genetic variance. To test this, we analyzed exome-array data from up to 33,231 non-diabetic individuals of European ancestry. We found exome-wide significant (P<5×10-7 evidence for two loci not previously highlighted by common variant GWAS: GLP1R (p.Ala316Thr, minor allele frequency (MAF=1.5% influencing FG levels, and URB2 (p.Glu594Val, MAF = 0.1% influencing FI levels. Coding variant associations can highlight potential effector genes at (non-coding GWAS signals. At the G6PC2/ABCB11 locus, we identified multiple coding variants in G6PC2 (p.Val219Leu, p.His177Tyr, and p.Tyr207Ser influencing FG levels, conditionally independent of each other and the non-coding GWAS signal. In vitro assays demonstrate that these associated coding alleles result in reduced protein abundance via proteasomal degradation, establishing G6PC2 as an effector gene at this locus. Reconciliation of single-variant associations and functional effects was only possible when haplotype phase was considered. In contrast to earlier reports suggesting that, paradoxically, glucose-raising alleles at this locus are protective against type 2 diabetes (T2D, the p.Val219Leu G6PC2 variant displayed a modest but directionally consistent association with T2D risk. Coding variant associations for glycemic traits in GWAS signals highlight PCSK1, RREB1, and ZHX3 as likely effector transcripts. These coding variant association signals do not have a major impact on the trait variance explained, but they do provide valuable biological insights.

  6. Identification and Functional Characterization of G6PC2 Coding Variants Influencing Glycemic Traits Define an Effector Transcript at the G6PC2-ABCB11 Locus

    Science.gov (United States)

    Mahajan, Anubha; Sim, Xueling; Ng, Hui Jin; Manning, Alisa; Rivas, Manuel A.; Highland, Heather M.; Locke, Adam E.; Grarup, Niels; Im, Hae Kyung; Cingolani, Pablo; Flannick, Jason; Fontanillas, Pierre; Fuchsberger, Christian; Gaulton, Kyle J.; Teslovich, Tanya M.; Rayner, N. William; Robertson, Neil R.; Beer, Nicola L.; Rundle, Jana K.; Bork-Jensen, Jette; Ladenvall, Claes; Blancher, Christine; Buck, David; Buck, Gemma; Burtt, Noël P.; Gabriel, Stacey; Gjesing, Anette P.; Groves, Christopher J.; Hollensted, Mette; Huyghe, Jeroen R.; Jackson, Anne U.; Jun, Goo; Justesen, Johanne Marie; Mangino, Massimo; Murphy, Jacquelyn; Neville, Matt; Onofrio, Robert; Small, Kerrin S.; Stringham, Heather M.; Syvänen, Ann-Christine; Trakalo, Joseph; Abecasis, Goncalo; Bell, Graeme I.; Blangero, John; Cox, Nancy J.; Duggirala, Ravindranath; Hanis, Craig L.; Seielstad, Mark; Wilson, James G.; Christensen, Cramer; Brandslund, Ivan; Rauramaa, Rainer; Surdulescu, Gabriela L.; Doney, Alex S. F.; Lannfelt, Lars; Linneberg, Allan; Isomaa, Bo; Tuomi, Tiinamaija; Jørgensen, Marit E.; Jørgensen, Torben; Kuusisto, Johanna; Uusitupa, Matti; Salomaa, Veikko; Spector, Timothy D.; Morris, Andrew D.; Palmer, Colin N. A.; Collins, Francis S.; Mohlke, Karen L.; Bergman, Richard N.; Ingelsson, Erik; Lind, Lars; Tuomilehto, Jaakko; Hansen, Torben; Watanabe, Richard M.; Prokopenko, Inga; Dupuis, Josee; Karpe, Fredrik; Groop, Leif; Laakso, Markku; Pedersen, Oluf; Florez, Jose C.; Morris, Andrew P.; Altshuler, David; Meigs, James B.; Boehnke, Michael; McCarthy, Mark I.; Lindgren, Cecilia M.; Gloyn, Anna L.

    2015-01-01

    Genome wide association studies (GWAS) for fasting glucose (FG) and insulin (FI) have identified common variant signals which explain 4.8% and 1.2% of trait variance, respectively. It is hypothesized that low-frequency and rare variants could contribute substantially to unexplained genetic variance. To test this, we analyzed exome-array data from up to 33,231 non-diabetic individuals of European ancestry. We found exome-wide significant (P<5×10-7) evidence for two loci not previously highlighted by common variant GWAS: GLP1R (p.Ala316Thr, minor allele frequency (MAF)=1.5%) influencing FG levels, and URB2 (p.Glu594Val, MAF = 0.1%) influencing FI levels. Coding variant associations can highlight potential effector genes at (non-coding) GWAS signals. At the G6PC2/ABCB11 locus, we identified multiple coding variants in G6PC2 (p.Val219Leu, p.His177Tyr, and p.Tyr207Ser) influencing FG levels, conditionally independent of each other and the non-coding GWAS signal. In vitro assays demonstrate that these associated coding alleles result in reduced protein abundance via proteasomal degradation, establishing G6PC2 as an effector gene at this locus. Reconciliation of single-variant associations and functional effects was only possible when haplotype phase was considered. In contrast to earlier reports suggesting that, paradoxically, glucose-raising alleles at this locus are protective against type 2 diabetes (T2D), the p.Val219Leu G6PC2 variant displayed a modest but directionally consistent association with T2D risk. Coding variant associations for glycemic traits in GWAS signals highlight PCSK1, RREB1, and ZHX3 as likely effector transcripts. These coding variant association signals do not have a major impact on the trait variance explained, but they do provide valuable biological insights. PMID:25625282

  7. NUSTART: A PC code for NUclear STructure And Radiative Transition analysis and supplementation

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, G.L.; Gardner, D.G.; Gardner, M.A.

    1990-10-01

    NUSTART is a computer program for the IBM PC/At. It is designed for use with the nuclear reaction cross-section code STAPLUS, which is a STAPRE-based CRAY computer code that is being developed at Lawrence Livermore National Laboratory. The NUSTART code was developed to handle large sets of discrete nuclear levels and the multipole transitions among these levels; it operates in three modes. The Data File Error Analysis mode analyzes an existing STAPLUS input file containing the levels and their multipole transition branches for a number of physics and/or typographical errors. The Interactive Data File Generation mode allows the user to create input files of discrete levels and their branching fractions in the format required by STAPLUS, even though the user enters the information in the (different) format used by many people in the nuclear structure field. In the Branching Fractions Calculations mode, the discrete nuclear level set is read, and the multipole transitions among the levels are computed under one of two possible assumptions: (1) the levels have no collective character, or (2) the levels are all rotational band heads. Only E1, M1, and E2 transitions are considered, and the respective strength functions may be constants or, in the case of E1 transitions, the strength function may be energy dependent. The first option is used for nuclei closed shells; the bandhead option may be used to vary the E1, M1, and E2 strengths for interband transitions. K-quantum number selection rules may be invoked if desired. 19 refs.

  8. Accelerated degradation of 14C-atrazine in an atrazine adapted field soil from Belgium

    Science.gov (United States)

    Hamacher, Georg; Jablonowski, Nicolai David; Martinazzo, Rosane; Accinelli, Cesare; Köppchen, Stephan; Langen, Ulrike; Linden, Andreas; Krause, Martina; Burauel, Peter

    2010-05-01

    unextractable, bound atrazine residues during the incubation process was monitored by accelerated solvent extraction, LC-MSMS and LSC analysis, subsequent to sample oxidation. Analysis of the atzABC and trzN genes that code for enzymes able to rapidly catabolize atrazine are under investigation. This outcome will give evidence of the global presence of an atrazine adapted soil microflora in atrazine treated field soils.

  9. Development of environmental dose assessment system (EDAS) code of PC version

    CERN Document Server

    Taki, M; Kobayashi, H; Yamaguchi, T

    2003-01-01

    A computer code (EDAS) was developed to assess the public dose for the safety assessment to get the license of nuclear reactor operation. This code system is used for the safety analysis of public around the nuclear reactor in normal operation and severe accident. This code was revised and composed for personal computer user according to the Nuclear Safety Guidelines reflected the ICRP1990 recommendation. These guidelines are revised by Nuclear Safety Commission on March, 2001, which are 'Weather analysis guideline for the safety assessment of nuclear power reactor', 'Public dose around the facility assessment guideline corresponding to the objective value for nuclear power light water reactor' and 'Public dose assessment guideline for safety review of nuclear power light water reactor'. This code has been already opened for public user by JAERI, and English version code and user manual are also prepared. This English version code is helpful for international cooperation concerning the nuclear safety assessme...

  10. Development of environmental dose assessment system (EDAS) code of PC version

    Energy Technology Data Exchange (ETDEWEB)

    Taki, Mitsumasa; Kikuchi, Masamitsu; Kobayashi, Hideo; Yamaguchi, Takenori [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-05-01

    A computer code (EDAS) was developed to assess the public dose for the safety assessment to get the license of nuclear reactor operation. This code system is used for the safety analysis of public around the nuclear reactor in normal operation and severe accident. This code was revised and composed for personal computer user according to the Nuclear Safety Guidelines reflected the ICRP1990 recommendation. These guidelines are revised by Nuclear Safety Commission on March, 2001, which are 'Weather analysis guideline for the safety assessment of nuclear power reactor', 'Public dose around the facility assessment guideline corresponding to the objective value for nuclear power light water reactor' and 'Public dose assessment guideline for safety review of nuclear power light water reactor'. This code has been already opened for public user by JAERI, and English version code and user manual are also prepared. This English version code is helpful for international cooperation concerning the nuclear safety assessment with JAERI. (author)

  11. T-MAPS, a PC-code for calculating average and local (``flash``) temperatures on sliding interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, F.A. [Argonne National Lab., IL (United States); Ashby, M.F. [Cambridge Univ. (United Kingdom). Dept. of Engineering

    1993-08-01

    When contacting solids slide, work is done against friction. Almost all the frictional work appears as heat, generated at or very close to the surface at which the two solids meet. The local increase in temperature influences both the friction and the rate of wear. In this paper, a user-friendly PC-code is described in which frictional heating is analyzed using a particularly simple framework. The code provides for a wide range of geometries for the two contacting solids, which may differ in their thermal and mechanical properties, and may not be in perfect contact with the heat sinks to which they are attached. The results of the code are presented as temperature maps which show the surface temperature of a sliding couple over a wide range of load and sliding velocity. The basic analysis underlying a previous version of the code was presented previously. We introduce here some significant changes, particularly with respect to the problem of asperity contact lifetime and show some excellent comparisons between various experimental results and predictions of the T-MAPS 4 software.

  12. 基于SoPC的QR二维码识别系统设计*%Design of QR code recognition system based on SoPC

    Institute of Scientific and Technical Information of China (English)

    李婉婉; 胡文龙; 李宏; 雷霞

    2014-01-01

    This paper introduces a QR code recognition system based on SoPC , whose purpose is to provide a kind of fast , low-cost , and interfaces-flexibled QR code reading scheme for handheld and embedded devices . The system consists of the image grabbing module , image preprocessing module , QR code decoding and error-correcting module , and peripheral interfaces module . Image grabbing module drives the CMOS camera to get the QR code image , with the image preprocessing module then preprocesses the image to facilitate decode , and the QR code decoding and error-correcting module realizes the code correcting and decoding towards QR code data .%介绍了一种基于 SoPC 的 QR 二维码识别系统,其目的在于为手持和嵌入式设备提供一种识别速度快、成本低、接口灵活的 QR 码识读方案。该系统包括图像采集、图像预处理、QR 码解码及纠错、外设接口等组成单元。图像采集单元驱动 CMOS 摄像头获取 QR 码图像,图像预处理单元将 QR 码图像进行一系列预处理以方便解码, QR 码解码及纠错单元实现对 QR 码的纠错与解码。

  13. Would banning atrazine benefit farmers?

    Science.gov (United States)

    Ackerman, Frank; Whited, Melissa; Knight, Patrick

    2014-01-01

    Atrazine, an herbicide used on most of the US corn (maize) crop, is the subject of ongoing controversy, with increasing documentation of its potentially harmful health and environmental impacts. Supporters of atrazine often claim that it is of great value to farmers; most recently, Syngenta, the producer of atrazine, sponsored an "Atrazine Benefits Team" (ABT) of researchers who released a set of five papers in 2011, reporting huge economic benefits from atrazine use in US agriculture. A critical review of the ABT papers shows that they have underestimated the growing problem of atrazine-resistant weeds, offered only a partial review of the effectiveness of alternative herbicides, and ignored the promising option of nonchemical weed management techniques. In addition, the most complete economic analysis in the ABT papers implies that withdrawal of atrazine would lead to a decrease in corn yields of 4.4% and an increase in corn prices of 8.0%. The result would be an increase in corn growers' revenues, equal to US$1.7 billion annually under ABT assumptions. Price impacts on consumers would be minimal: at current levels of ethanol production and use, gasoline prices would rise by no more than US$0.03 per gallon; beef prices would rise by an estimated US$0.01 for a 4-ounce hamburger and US$0.05 for an 8-ounce steak. Thus withdrawal of atrazine would boost farm revenues, while only changing consumer prices by pennies.

  14. Atrazine dissipation in s-triazine-adapted and nonadapted soil from Colorado and Mississippi: implications of enhanced degradation on atrazine fate and transport parameters.

    Science.gov (United States)

    Krutz, L Jason; Shaner, Dale L; Accinelli, Cesare; Zablotowicz, Robert M; Henry, W Brien

    2008-01-01

    Soil bacteria have developed novel metabolic abilities resulting in enhanced atrazine degradation. Consequently, there is a need to evaluate the effects of enhanced degradation on parameters used to model atrazine fate and transport. The objectives of this study were (i) to screen Colorado (CO) and Mississippi (MS) atrazine-adapted and non-adapted soil for genes that code for enzymes able to rapidly catabolize atrazine and (ii) to compare atrazine persistence, Q(10), beta, and metabolite profiles between adapted and non-adapted soils. The atzABC and/or trzN genes were detected only in adapted soil. Atrazine's average half-life in adapted soil was 10-fold lower than that of the non-adapted soil and 18-fold lower than the USEPA estimate of 3 to 4 mo. Q(10) was greater in adapted soil. No difference in beta was observed between soils. The accumulation and persistence of mono-N-dealkylated metabolites was lower in adapted soil; conversely, under suboptimal moisture levels in CO adapted soil, hydroxyatrazine concentrations exceeded 30% of the parent compounds' initial mass. Results indicate that (i) enhanced atrazine degradation and atzABC and/or trzN genes are likely widespread across the Western and Southern corn-growing regions of the USA; (ii) persistence of atrazine and its mono-N-dealkylated metabolites is significantly reduced in adapted soil; (iii) hydroxyatrazine can be a major degradation product in adapted soil; and (iv) fate, transport, and risk assessment models that assume historic atrazine degradation pathways and persistence estimates will likely overpredict the compounds' transport potential in adapted soil.

  15. PC Pricer

    Data.gov (United States)

    U.S. Department of Health & Human Services — The PC Pricer is a tool used to estimate Medicare PPS payments. The final payment may not be precise to how payments are determined in the Medicare claims processing...

  16. Atrazine removal in Danish anaerobic aquifers

    DEFF Research Database (Denmark)

    Pedersen, Philip Grinder; Arildskov, N.P.; Albrechtsen, Hans-Jørgen

    2002-01-01

    process was abiotic since atrazine was also removed from microbially inhibited autoclaved and chloroform amended controls, although in controls amended with mercury, atrazine removal was slowed down. (ring-U-C-14)- atrazine amended samples showed no mineralization to (CO2)-C-14 or transformation...

  17. Atrazine leaching from biochar-amended soils.

    Science.gov (United States)

    Delwiche, Kyle B; Lehmann, Johannes; Walter, M Todd

    2014-01-01

    The herbicide atrazine is used extensively throughout the United States, and is a widespread groundwater and surface water contaminant. Biochar has been shown to strongly sorb organic compounds and could be used to reduce atrazine leaching. We used lab and field experiments to determine biochar impacts on atrazine leaching under increasingly heterogeneous soil conditions. Application of pine chip biochar (commercially pyrolyzed between 300 and 550 °C) reduced cumulative atrazine leaching by 52% in homogenized (packed) soil columns (p=0.0298). Biochar additions in undisturbed soil columns did not significantly (p>0.05) reduce atrazine leaching. Mean peak groundwater atrazine concentrations were 53% lower in a field experiment after additions of 10 t ha(-1) acidified biochar (p=0.0056) relative to no biochar additions. Equivalent peat applications by dry mass had no effect on atrazine leaching. Plots receiving a peat-biochar mixture showed no reduction, suggesting that the peat organic matter may compete with atrazine for biochar sorption sites. Several individual measurement values outside the 99% confidence interval in perched groundwater concentrations indicate that macropore structure could contribute to rare, large leaching events that are not effectively reduced by biochar. We conclude that biochar application has the potential to decrease peak atrazine leaching, but heterogeneous soil conditions, especially preferential flow paths, may reduce this impact. Long-term atrazine leaching reductions are also uncertain.

  18. Soil mesocosm studies on atrazine bioremediation.

    Science.gov (United States)

    Sagarkar, Sneha; Nousiainen, Aura; Shaligram, Shraddha; Björklöf, Katarina; Lindström, Kristina; Jørgensen, Kirsten S; Kapley, Atya

    2014-06-15

    Accumulation of pesticides in the environment causes serious issues of contamination and toxicity. Bioremediation is an ecologically sound method to manage soil pollution, but the bottleneck here, is the successful scale-up of lab-scale experiments to field applications. This study demonstrates pilot-scale bioremediation in tropical soil using atrazine as model pollutant. Mimicking field conditions, three different bioremediation strategies for atrazine degradation were explored. 100 kg soil mesocosms were set-up, with or without atrazine application history. Natural attenuation and enhanced bioremediation were tested, where augmentation with an atrazine degrading consortium demonstrated best pollutant removal. 90% atrazine degradation was observed in six days in soil previously exposed to atrazine, while soil without history of atrazine use, needed 15 days to remove the same amount of amended atrazine. The bacterial consortium comprised of 3 novel bacterial strains with different genetic atrazine degrading potential. The progress of bioremediation was monitored by measuring the levels of atrazine and its intermediate, cyanuric acid. Genes from the atrazine degradation pathway, namely, atzA, atzB, atzD, trzN and trzD were quantified in all mesocosms for 60 days. The highest abundance of all target genes was observed on the 6th day of treatment. trzD was observed in the bioaugmented mesocosms only. The bacterial community profile in all mesocosms was monitored by LH-PCR over a period of two months. Results indicate that the communities changed rapidly after inoculation, but there was no drastic change in microbial community profile after 1 month. Results indicated that efficient bioremediation of atrazine using a microbial consortium could be successfully up-scaled to pilot scale.

  19. New aspects on atrazine biodegradation

    Directory of Open Access Journals (Sweden)

    Luciane Sene

    2010-04-01

    Full Text Available The world practice of using agrochemicals for long periods, in an indiscriminated and abusive way, has been a concern of the authorities involved in public health and sustainability of the natural resources, as a consequence of environmental contamination. Agrochemicals refer to a broad range of insecticides, fungicides and herbicides, and among them stands out atrazine, a herbicide intensively used in sugarcane, corn and sorghum cultures, among others. Researches have demonstrated that atrazine has toxic effects in algae, aquatic plants, aquatic insects, fishes and mammals. Due to the toxicity and persistence of atrazine in the environment, the search of microbial strains capable of degrading it is fundamental to the development of bioremediation processes, as corrective tools to solve the current problems of the irrational use of agrochemicals. This review relates the main microbial aspects and research on atrazine degradation by isolated microbial species and microbial consortia, as well as approaches on the development of techniques for microbial removal of atrazine in natural environments.A prática mundial do uso de agroquímicos por períodos extensos, de maneira indiscriminada e abusiva, tem mobilizado as autoridades envolvidas em saúde pública e sustentabilidade de fontes naturais, como uma conseqüência da contaminação ambiental. Agroquímicos referem-se a uma ampla variedade de inseticidas, fungicidas e herbicidas, entre estes a atrazina, um herbicida intensivamente usado em culturas de cana-de-açúcar, milho, sorgo, entre outros. Pesquisadores têm demonstrado que a atrazina tem efeitos tóxicos em algas, plantas aquáticas, insetos aquáticos, peixes e mamíferos. Devido à toxicidade e à persistência da atrazina no ambiente, a busca de linhagens microbianas capazes de degradá-la é fundamental para o desenvolvimento de processos de biorremediação, com uma ferramenta corretiva para solucionar problemas decorridos do uso

  20. 76 FR 56754 - Petition Requesting Ban on Use and Production of Atrazine; Notice of Availability

    Science.gov (United States)

    2011-09-14

    ... Classification System (NAICS) codes have been provided to assist you and others in determining whether this... concern for impacts on amphibians and other aquatic species as well as concern for potential risks to human health. Information on EPA's regulation of atrazine with regard to amphibians, ]...

  1. Hydrolysis kinetics of atrazine and influence factors

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The hydrolysis kinetics of atrazine in distilled water and leaching water from soil, and their influence factors were studied by incubation at 35℃ and HPLC analysis method in this paper. The kinetic process of atrazine hydrolysis can be described by the first-order reaction law. The results showed that the hydrolysis rate constants k in leaching water and distilled water were 1.606x10-3/d and 1.055x10-3/d, respectively; the half-life of atrazine hydrolysis in distilled water at pH 3, pH 4.5 and pH 8 were 373 days, 522 days and 657 days respectively. The results also showed that the proton in reaction solution can catalyze the atrazine hydrolysis; humic acid and NH4+ etc. substances in aqueous solution can facilitate atrazine hydrolysis; rate constants of atrazine hydrolysis with humic acid and NH4NO3 were 2.431x10-3/d and 1.498x10-3/d respectively which were 2.3 and 1.42 times of control(1.055x10-3/d); anion NO3- can inhibit catalysis of humic acid to atrazine hydrolysis.

  2. Biodegradation of atrazine by three transgenic grasses and alfalfa expressing a modified bacterial atrazine chlorohydrolase gene.

    Science.gov (United States)

    Vail, Andrew W; Wang, Ping; Uefuji, Hirotaka; Samac, Deborah A; Vance, Carroll P; Wackett, Lawrence P; Sadowsky, Michael J

    2015-06-01

    The widespread use of atrazine and other s-triazine herbicides to control weeds in agricultural production fields has impacted surface and groundwater in the United States and elsewhere. We previously reported the cloning, sequencing, and expression of six genes involved in the atrazine biodegradation pathway of Pseudomonas sp. strain ADP, which is initiated by atzA, encoding atrazine chlorohydrolase. Here we explored the use of enhanced expression of a modified bacterial atrazine chlorohydrolase, p-AtzA, in transgenic grasses (tall fescue, perennial ryegrass, and switchgrass) and the legume alfalfa for the biodegradation of atrazine. Enhanced expression of p-AtzA was obtained by using combinations of the badnavirus promoter, the maize alcohol dehydrogenase first intron, and the maize ubiquitin promoter. For alfalfa, we used the first intron of the 5'-untranslated region tobacco alcohol dehydrogenase gene and the cassava vein mosaic virus promoter. Resistance of plants to atrazine in agar-based and hydroponic growth assays was correlated with in vivo levels of gene expression and atrazine degradation. The in planta expression of p-atzA enabled transgenic tall fescue to transform atrazine into hydroxyatrazine and other metabolites. Results of our studies highlight the potential use of transgenic plants for bioremediating atrazine in the environment.

  3. Raster dataset showing the probability of detecting atrazine/desethyl-atrazine in ground water in Colorado, hydrogeomorphic regions and atrazine use estimates included.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset is one of eight datasets produced by this study. Four of the datasets predict the probability of detecting atrazine and(or) desethyl-atrazine (a...

  4. Raster dataset showing the probability of detecting atrazine/desethyl-atrazine in ground water in Colorado, hydrogeomorphic regions and atrazine use estimates not included.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset is one of eight datasets produced by this study. Four of the datasets predict the probability of detecting atrazine and(or) desethyl-atrazine (a...

  5. Raster dataset showing the probability of detecting atrazine/desethyl-atrazine in ground water in Colorado, hydrogeomorphic regions not included and atrazine use estimates included.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset is one of eight datasets produced by this study. Four of the datasets predict the probability of detecting atrazine and(or) desethyl-atrazine (a...

  6. Raster dataset showing the probability of detecting atrazine/desethyl-atrazine in ground water in Colorado, hydrogeomorphic regions included and atrazine use estimates not included.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset is one of eight datasets produced by this study. Four of the datasets predict the probability of detecting atrazine and(or) desethyl-atrazine (a...

  7. Nitrogen limited biobarriers remove atrazine from contaminated water: Laboratory studies

    Science.gov (United States)

    Hunter, William J.; Shaner, Dale L.

    2009-01-01

    Atrazine is one of the most frequently used herbicides. This usage coupled with its mobility and recalcitrant nature in deeper soils and aquifers makes it a frequently encountered groundwater contaminant. We formed biobarriers in sand filled columns by coating the sand with soybean oil; after which, we inoculated the barriers with a consortium of atrazine-degrading microorganisms and evaluated the ability of the barriers to remove atrazine from a simulated groundwater containing 1 mg L - 1 atrazine. The soybean oil provided a carbon rich and nitrogen poor substrate to the microbial consortium. Under these nitrogen-limiting conditions it was hypothesized that bacteria capable of using atrazine as a source of nitrogen would remove atrazine from the flowing water. Our hypothesis proved correct and the biobarriers were effective at removing atrazine when the nitrogen content of the influent water was low. Levels of atrazine in the biobarrier effluents declined with time and by the 24th week of the study no detectable atrazine was present (limit of detection atrazine were also removed by the biobarriers; when biobarriers were fed 16.3 mg L - 1 atrazine 97% was degraded. When nitrate (5 mg L - 1 N), an alternate source of nitrogen, was added to the influent water the atrazine removal efficiency of the barriers was reduced by almost 60%. This result supports the hypothesis that atrazine was degraded as a source of nitrogen. Poisoning of the biobarriers with mercury chloride resulted in an immediate and large increase in the amount of atrazine in the barrier effluents confirming that biological activity and not abiotic factors were responsible for most of the atrazine degradation. The presence of hydroxyatrazine in the barrier effluents indicated that dehalogenation was one of the pathways of atrazine degradation. Permeable barriers might be formed in-situ by the injection of innocuous vegetable oil emulsions into an aquifer or sandy soil and used to remove atrazine from a

  8. Atrazine Removal from Aqueous Solutions using Submerged Biological Aerated Filter

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Baghapour

    2013-06-01

    Full Text Available Atrazine is widely used in the agriculture as an herbicide. Due to its high mobility, Atrazine leaks into the groundwaters, surface waters, and drinking water wells. Many physical and chemical methods have been suggested for removing Atrazine from aquatic environments. However, these methods are very costly, have many performance problems, produce a lot of toxic intermediates which are very harmful and dangerous, and cannot completely mineralize Atrazine. In this study, biodegradation of Atrazine by microbial consortium was evaluated in the aquatic environment. In order to assess the Atrazine removal from the aquatic environment, submerged biological aerated filter (SBAF was fed with synthetic wastewater based on sucrose and Atrazine at different hydraulic retention times (HRTs. The maximum efficiencies for Atrazine and Soluble Chemical Oxygen Demand (SCOD removal were 97.9% and 98.9%, respectively. The study findings showed that Stover-Kincannon model had very good fitness (R2 > 99% in loading Atrazine in the biofilter and by increasing the initial concentration of Atrazine, the removal efficiency increased. Aerobic mixed biofilm culture was observed to be suitable for the treatment of Atrazine from aquatic environment. There was no significant inhibition effect on mixed aerobic microbial consortia. Atrazine degradation depended on the strength of wastewater and the amount of Atrazine in the influent

  9. Determining potential for microbial atrazine degradation in agricultural drainage ditches.

    Science.gov (United States)

    Tyler, Heather L; Khalid, Sheza; Jackson, Colin R; Moore, Matthew T

    2013-01-01

    Passage of agricultural runoff through vegetated drainage ditches has been shown to reduce the amount of pesticides, such as atrazine, exiting out of agricultural watersheds. Previous studies have found that microbial communities in soil from fields treated with atrazine display enhanced rates of atrazine degradation. However, no studies have examined the potential for atrazine degradation in ditches used to drain these lands. The purpose of the current study was to determine the potential of the drainage ditch soil microbial community for atrazine degradation. Soil samples were collected from fields and adjacent drainage ditches and from nonagricultural land with no previous exposure to atrazine. Polymerase chain reaction analysis indicated widespread presence of atrazine degradation genes in fields and ditches. Potential for degradation was determined by following the decrease of atrazine in spiked soil samples over a 28-d incubation period. Greater than 95% of atrazine was degraded in field and ditch soils, whereas only 68.5 ± 1.3% was degraded in the nonagricultural control. Comparison with autoclaved soil samples indicated the primary mechanism of atrazine degradation in agricultural soils was microbially mediated, whereas its breakdown in nonagricultural soil appeared to be the byproduct of abiotic processes. Therefore, microbial communities in drainage ditch sediments have the potential to play a role in atrazine removal from agricultural runoff by breaking down atrazine deposited in sediments and limiting the amount of this herbicide carried into downstream ecosystems.

  10. Oxidation of atrazine by photoactivated potassium persulfate in aqueous solutions

    Science.gov (United States)

    Khandarkhaeva, M. S.; Aseev, D. G.; Sizykh, M. R.; Batoeva, A. A.

    2016-11-01

    General laws of the photochemical oxidation of atrazine by inorganic peroxo compounds under the impact of solar radiation are studied. It is found that almost complete conversion of atrazine can be achieved via photochemical oxidation with persulfate after 120 min, but no deep mineralization is observed. The effect an aqueous matrix has on the processes of atrazine degradation in combined oxidation systems is considered.

  11. 40 CFR 180.220 - Atrazine; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Atrazine; tolerances for residues. 180... Atrazine; tolerances for residues. (a) General. Tolerances are established for the combined residues of the herbicide atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) and its chlorinated metabolites...

  12. Determining potential for microbial atrazine degradation in agricultural drainage ditches

    Science.gov (United States)

    Passage of agricultural runoff through vegetated drainage ditches has been shown to reduce the amount of pesticides, such as atrazine, exiting agricultural watersheds. Previous studies found that microbial communities in soil from fields treated with atrazine display enhanced rates of atrazine degr...

  13. Disposition of atrazine metabolites following uptake and degradation of atrazine in switchgrass.

    Science.gov (United States)

    Albright, Vurtice C; Coats, Joel R

    2014-01-01

    Extensive use of the agricultural herbicide atrazine has led to contamination of numerous ground and surface water bodies. Research has shown that it can have a variety of negative impacts on numerous non-target organisms in the environment. Phytoremediation is one strategy that has been studied to remove atrazine contamination. This paper investigates the hypothesis that switchgrass (Panicum virgatum) can exude metabolites of atrazine after uptake and degradation, which has been suggested by prior research. Pots planted with switchgrass were treated with a 4 ppm solution of atrazine spiked with [14C]atrazine. After 4 days, switchgrass plants were transplanted to new pots with fresh sand. Four days later, the pots were sacrificed, and sand and plant samples were extracted. Plant and sand samples were analyzed for the presence of atrazine and its major metabolites. The percentage of radiotracer remaining as the parent atrazine was observed to decrease over the course of the study while the percentages of the metabolites were observed to increase. The presence of the metabolite cyanuric acid in a switchgrass phytoremediation system is reported for the first time.

  14. Biodegradation of s-triazine herbicide atrazine by Enterobacter cloacae and Burkholderia cepacia sp. from long-term treated sugarcane-cultivated soils in Kenya.

    Science.gov (United States)

    Ngigi, Anastasiah N; Getenga, Zachary M; Boga, Hamadi I; Ndalut, Paul K

    2012-09-01

    In this study soils from sugarcane-cultivated fields were screened for bacterial species capable of atrazine (6-chloro-N²-ethyl-N⁴-isopropyl-1,3,5-triazine-2,4-diamine) degradation due to long exposure of the soils to this herbicide. To enrich for atrazine degraders, Minimal Salt Medium containing atrazine as the sole N source and glucose as the C source was inoculated with soils impacted with this herbicide and incubated. Bacterial growth was monitored by measuring optical density. The degradation of atrazine was followed by measuring residual atrazine in liquid cultures over a given time period by high performance liquid chromatography. Bacterial strains isolated from the enrichment cultures were characterized by biochemical tests and identified by 16S rRNA gene sequencing. Two bacterial strains coded ISL 8 and ISL 15 isolated from two different fields were shown to have 94 and 96% 16S rRNA gene sequence similarity to Burkholderia cepacia respectively. Another bacterial sp., ISL 14 was closely related to Enterobacter cloacae with a 96% 16S rRNA gene sequence similarity. There was not much difference between the extents of atrazine degradation by the enrichment cultures with communities (79-82% applied amount) from which pure strains were isolated and the pure strains themselves in liquid cultures that showed a degradation of 53-83% of applied amount. The study showed existence of bacterial strains in different sugarcane-cultivated fields which can use atrazine as a nitrogen source. The bacterial strains isolated can be used to enhance the degradation of atrazine in contaminated soils where atrazine is still considered to be recalcitrant.

  15. Sorption and transport of atrazine in an agricultural soil

    Science.gov (United States)

    Hakan Akyol, Nihat

    2014-05-01

    Sorption and transport of atrazine in an agricultural soil Atrazine is one of the most commonly used herbicides in large quantity worldwide. The objective of this study was to perform some batch and column experiments to examine the transport of atrazine in an agricultural soil from Turkey. Batch experiments indicated that sorption isotherm was nonlinear with a freundlich isotherm over a range of concentration (0.2-10 mg/L) examined. Column experiments showed that transport of atrazine in the soil was moderately retarded compared to non-reactive tracer (R = 2.9-4.0). The degree of retardation decreased with increasing atrazine concentration and residance time had negligable impact on degree of sorption. Flow interruption tests in the column experiments indicated that the rate-limited desorption of atrazine mainly controlled the non-ideal transport of atrazine due to the presence of organic matter fraction (0.83 %) in the soil. Sorption and desorption behavior of atrazine in such soils could have important impacts for risk assessment of atrazine-contaminated soil and should be taken into account in the regulation, management, and remediation of atrazine-contaminated sites. Keywords: Atrazine, Agricultural soil, Batch, Column, Desorption, Rate-limited desorption, Sorption, Transport.

  16. Scale-PC shielding analysis sequences

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, S.M.

    1996-05-01

    The SCALE computational system is a modular code system for analyses of nuclear fuel facility and package designs. With the release of SCALE-PC Version 4.3, the radiation shielding analysis community now has the capability to execute the SCALE shielding analysis sequences contained in the control modules SAS1, SAS2, SAS3, and SAS4 on a MS- DOS personal computer (PC). In addition, SCALE-PC includes two new sequences, QADS and ORIGEN-ARP. The capabilities of each sequence are presented, along with example applications.

  17. Photochemical processes for atrazine degradation: methodological approach.

    Science.gov (United States)

    Héquet, V; Gonzalez, C; Le Cloirec, P

    2001-12-01

    Numerous studies have been carried out on s-triazines, and more specifically on atrazine, with the long-term objective of resolving the problems caused by these herbicides: removing them from drinking water. However, applications have remained too limited. So far, processes based on photochemical degradation have been little implemented. We, therefore, investigated the development of photochemical processes, emphasizing their capacity to degrade triazine by photolytic and photocatalytic mode. The study sought to assess the performance of these ssstems. Experiments ts showed that according to a medium pressure mercury source (UV-Vis irradiation), the photolytic degradation of atrazine was very efficient, with a best atrazine degradation half-life shorter that 5 min. The main degradation pathway was deshalogenation. The photocatalytic degradation of atrazine under irradiation over 290 nm in the presence of titanium dioxide was shown to be efficient too, with a half-life of about 20 min. In this case an experimental design was conducted so as to assess the influence of various parameters: pH, water medium, and amount of catalyst. There has been observational evidence for the efficiency of the processes investigated here and for potential technological developments as regards drinking water treatment.

  18. Bioaccumulation and degradation of atrazine in several Chinese ryegrass genotypes.

    Science.gov (United States)

    Sui, Ying; Yang, Hong

    2013-12-01

    Soil pollution with herbicides is a global problem. Before phytoremediation technology is developed for the plant-based clean-up of polluted soils, investigation of potential plants that can be used to accumulate and degrade herbicides is a critical step. In this study, three selected genotypes of ryegrass were comprehensively analyzed with regard to the atrazine accumulation, degradation and toxicological response. Under the conditions of soil with 0.8 mg kg(-1) atrazine, the maximum value for atrazine accumulation was 2.70 mg kg(-1) in shoots and 0.58 mg kg(-1) in roots. The residue of atrazine in soil with ryegrass cultivation was much lower than that in soil without ryegrass cultivation. Also, the content of atrazine residues in the rhizosphere was significantly lower than that in the non-rhizosphere soil. Activities of several enzymes (urease, invertase, polyphenol oxidase, acid phosphatase and alkaline phosphatase) in soil were assayed. These enzymes were depressed by atrazine but activated by ryegrass cultivation, even in the presence of atrazine. Finally, comparative studies have been conducted on the ryegrass genotypes in response to atrazine. They showed different capacities of degradation and bioaccumulation of atrazine. One of the grass cultivars Changjiang II (CJ) had better growth and higher levels of chlorophyll, but displayed less oxidative injury than two others, Abode (AB) and Jiewei (JW), under atrazine exposure.

  19. Accumulation and toxicological response of atrazine in rice crops.

    Science.gov (United States)

    Zhang, Jia Jun; Lu, Yi Chen; Zhang, Jin Jin; Tan, Li Rong; Yang, Hong

    2014-04-01

    Atrazine is one of the most widely used herbicides for controlling weeds and grasses. Due to its intensive use, it has become a serious contaminant in soil and water. To evaluate impact of atrazine on graminaceous crops, experiments focusing on atrazine accumulation and toxic response in rice (Oryza sativa) were carried out. Treatment with atrazine at 0.05-0.8 mg L(-1) for 6 d reduced elongation of shoot and root. Compared with a mock treatment, the elongation of shoot with atrazine was 67.1 percent of the control, whereas that of root was 79.5 percent, indicating that the shoot was more affected than the root. Atrazine was readily absorbed by rice from media. Although the quantitative absorption of atrazine was positively correlated with the external supply of the herbicide, translocation of atrazine from roots to the above-ground was reduced from 39.88±6.26 (at 0.05 mg L(-1)) to 9.25±0.27 (0.8 mg L(-1)). While accumulation of atrazine in rice plants led to toxic responses such as over-generation of hydrogen peroxide and superoxide anions, it triggered the plant defense system against the herbicide-induced oxidative stress. This was best presented by the enhanced activities of several antioxidant enzymes (e.g. superoxide dismutase, catalase and peroxidase) and expression of genes responsible for the tolerance to atrazine toxicity.

  20. Label-free disposable immunosensor for detection of atrazine.

    Science.gov (United States)

    Belkhamssa, Najet; Justino, Celine I L; Santos, Patrícia S M; Cardoso, Susana; Lopes, Isabel; Duarte, Armando C; Rocha-Santos, Teresa; Ksibi, Mohamed

    2016-01-01

    This work reports the construction of a fast, disposable, and label-free immunosensor for the determination of atrazine. The immunosensor is based on a field effect transistor (FET) where a network of single-walled carbon nanotubes (SWCNTs) acts as the conductor channel, constituting carbon nanotubes field effect transistors (CNTFETs). Anti-atrazine antibodies were adsorbed onto the SWCNTs and subsequently the SWCNTs were protected with Tween 20 to prevent the non-specific binding of bacteria or proteins. The principle of the immunoreaction consists in the direct adsorption of atrazine specific antibodies (anti-atrazine) to SWCNTs networks. After exposed to increasing concentrations of atrazine, the CNTFETs could be used as useful label-free platforms to detect atrazine. Under the optimal conditions, a limit of detection as low as 0.001 ng mL(-1) was obtained, which is lower than that of other methods for the atrazine detection, and in a working range between 0.001 and 10 ng mL(-1). The average recoveries obtained for real water samples spiked with atrazine varied from 87.3% to 108.0%. The results show that the constructed sensors display a high sensitivity and could be useful tools for detecting pesticides like atrazine at low concentrations. They could be also applied to the determination of atrazine in environmental aqueous samples, such as seawater and riverine water.

  1. Atrazine reduces reproduction in fathead minnow (Pimephales promelas)

    Science.gov (United States)

    Tillitt, D.E.; Papoulias, D.M.; Whyte, J.J.; Richter, C.A.

    2010-01-01

    Atrazine, the widely used herbicide, has shown to affect the hypothalamus-pituitary-gonad axis in certain vertebrate species, but few studies have examined reproductive effects of this chemical on fish. Our study was designed to evaluate a population endpoint (egg production) in conjunction with histological (e.g., gonad development) and biochemical (e.g., hormone production) phenotypes associated with atrazine exposure in fathead minnows. Adult virgin breeding groups of 1 male and 2 females were exposed to nominal concentrations of 0, 0.5, 5.0, and 50 ??g/L of atrazine in a flow-through diluter for 14 or 30 days. Total egg production was lower (19-39%) in all atrazine-exposed groups as compared to the controls. The decreases in cumulative egg production of atrazine treated fish were significant by 17-20 days of exposure. Reductions in egg production in atrazine treatment groups were most attributable to reduced numbers of spawning events with increased atrazine exposure concentrations. Gonad abnormalities were observed in both male and female fish of atrazine-exposed fish. Our results also indicate that atrazine reduces egg production through alteration of final maturation of oocytes. The reproductive effects observed in this study warrant further investigation and evaluation of the potential risks posed by atrazine, particularly feral populations of fish from streams in agricultural areas with high use of this herbicide. ?? 2010.

  2. Monte Carlo tests of the ELIPGRID-PC algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, J.R.

    1995-04-01

    The standard tool for calculating the probability of detecting pockets of contamination called hot spots has been the ELIPGRID computer code of Singer and Wickman. The ELIPGRID-PC program has recently made this algorithm available for an IBM{reg_sign} PC. However, no known independent validation of the ELIPGRID algorithm exists. This document describes a Monte Carlo simulation-based validation of a modified version of the ELIPGRID-PC code. The modified ELIPGRID-PC code is shown to match Monte Carlo-calculated hot-spot detection probabilities to within {plus_minus}0.5% for 319 out of 320 test cases. The one exception, a very thin elliptical hot spot located within a rectangular sampling grid, differed from the Monte Carlo-calculated probability by about 1%. These results provide confidence in the ability of the modified ELIPGRID-PC code to accurately predict hot-spot detection probabilities within an acceptable range of error.

  3. Atrazine reduces reproduction in Japanese medaka (Oryzias latipes).

    Science.gov (United States)

    Papoulias, Diana M; Tillitt, Donald E; Talykina, Melaniya G; Whyte, Jeffrey J; Richter, Catherine A

    2014-09-01

    Atrazine is an effective broadleaf herbicide and the second most heavily used herbicide in the United States. Effects along the hypothalamus-pituitary-gonad axis in a number of vertebrate taxa have been demonstrated. Seasonally elevated concentrations of atrazine in surface waters may adversely affect fishes, but only a few studies have examined reproductive effects of this chemical. The present study was designed to evaluate a population endpoint (egg production) in conjunction with histological (reproductive stage, gonad pathology) and biochemical (aromatase activity, sex hormone production) phenotypes associated with atrazine exposure in Japanese medaka. Adult virgin breeding groups of one male and four females were exposed to nominal concentrations of 0, 0.5, 5.0, and 50 μg/L (0, 2.3, 23.2, 231 nM) of atrazine in a flow-through diluter for 14 or 38 days. Total egg production was lower (36-42%) in all atrazine-exposed groups as compared to the controls. The decreases in cumulative egg production of atrazine-treated fish were significant by exposure day 24. Reductions in total egg production in atrazine treatment groups were most attributable to a reduced number of eggs ovulated by females in atrazine-treated tanks. Additionally, males exposed to atrazine had a greater number of abnormal germ cells. There was no effect of atrazine on gonadosomatic index, aromatase protein, or whole body 17 β-estradiol or testosterone. Our results suggest that atrazine reduces egg production through alteration of final maturation of oocytes. The reduced egg production observed in this study was very similar to our previously reported results for fathead minnow. This study provides further information with which to evaluate atrazine's risk to fish populations.

  4. Atrazine reduces reproduction in Japanese medaka (Oryzias latipes)

    Science.gov (United States)

    Papoulias, Diana M.; Tillitt, Donald E.; Talyknia, Melaniya G.; Whyte, Jeffrey J.; Richter, Catherine A.

    2014-01-01

    Atrazine is an effective broadleaf herbicide and the second most heavily used herbicide in the United States. Effects along the hypothalamus–pituitary–gonad axis in a number of vertebrate taxa have been demonstrated. Seasonally elevated concentrations of atrazine in surface waters may adversely affect fishes, but only a few studies have examined reproductive effects of this chemical. The present study was designed to evaluate a population endpoint (egg production) in conjunction with histological (reproductive stage, gonad pathology) and biochemical (aromatase activity, sex hormone production) phenotypes associated with atrazine exposure in Japanese medaka. Adult virgin breeding groups of one male and four females were exposed to nominal concentrations of 0, 0.5, 5.0, and 50 μg/L (0, 2.3, 23.2, 231 nM) of atrazine in a flow-through diluter for 14 or 38 days. Total egg production was lower (36–42%) in all atrazine-exposed groups as compared to the controls. The decreases in cumulative egg production of atrazine-treated fish were significant by exposure day 24. Reductions in total egg production in atrazine treatment groups were most attributable to a reduced number of eggs ovulated by females in atrazine-treated tanks. Additionally, males exposed to atrazine had a greater number of abnormal germ cells. There was no effect of atrazine on gonadosomatic index, aromatase protein, or whole body 17 β-estradiol or testosterone. Our results suggest that atrazine reduces egg production through alteration of final maturation of oocytes. The reduced egg production observed in this study was very similar to our previously reported results for fathead minnow. This study provides further information with which to evaluate atrazine's risk to fish populations.

  5. Degradation of atrazine by an acclimatized soil fungal isolate.

    Science.gov (United States)

    Singh, Shashi B; Lal, Shashi P; Pant, Shashi; Kulshrestha, Gita

    2008-01-01

    A fungal strain able to use atrazine (2-chloro-4-ethylamino-5-isopropylamino-1,3,5-triazine) as a source of nitrogen was isolated from a corn field soil that has been previously treated with the herbicide. This strain was purified and acclimatized to atrazine at a higher level in the laboratory. A supplemented N was required to trigger the reaction. Atrazine was degraded at a faster rate in inoculated mineral salt medium (MSM) than non-inoculated MSM. Within 20 days, nearly 34% of the atrazine was degraded in inoculated medium while only 2% of the herbicide was degraded in non-inoculated medium. Degradation of atrazine by the isolated fungal strain was also studied in sterile and non-sterile soil to determine the compatibility of the isolated strain with native microorganisms in soil. The degradation of atrazine was found to be more in inoculated sterile soil than in inoculated non-sterile soil. Cell free extract (CFE) of fungal mycelium degraded about 50% of the atrazine in buffer in 96 hours compared to the control. Four atrazine metabolites were isolated and characterized by LCMS. On the basis of morphological parameters the isolate was identified as Penicillium species. Results indicated that the microorganism may be useful for remediation of atrazine-contaminated soil.

  6. Kinetics and mass transfer of atrazine ozonation

    Directory of Open Access Journals (Sweden)

    Bruno Abreu Calfa

    2010-08-01

    Full Text Available The kinetics of the atrazine oxidation in aqueous solution by ozone was studied under different initial pH conditions and in the presence of a hydroxyl radical scavenger at pH 2.8. It was verified that the process took place mainly through radical reaction, even in acid medium. Therefore, a relatively high value of 26.4 L/(mol.s for the rate constant of the direct reaction between molecular ozone and atrazine was found. After 10 minutes of oxidation, the degradation of the herbicide was more effective for pH 10.30 than for pHs 6.25 and 2.80. The mass transfer of ozone from the gas phase to the liquid phase was strongly affected by the oxygen flowrate and to a lesser extent by the stirring speed.

  7. Transfer of atrazine degradation capability to mineralize aged ¹⁴C-labeled atrazine residues in soils.

    Science.gov (United States)

    Jablonowski, Nicolai David; Krutz, Jason L; Martinazzo, Rosane; Zajkoska, Petra; Hamacher, Georg; Borchard, Nils; Burauel, Peter

    2013-07-03

    The degradation of environmentally long-term aged (22 years) ¹⁴C-labeled atrazine residues in soil stimulated by inoculation with atrazine-adapted soil from Belgium, the United States (U.S.), and Brazil at two different moisture regimes (50% WHCmax/slurried conditions) was evaluated. Inoculation of the soil containing the aged ¹⁴C-labeled atrazine residues with 5, 50, and 100% (w/w) Belgian, U.S., or Brazilian atrazine-adapted soil increased ¹⁴C-atrazine residue mineralization by a factor of 3.1-13.9, depending upon the amount of atrazine-adapted soil inocula and the moisture conditions. Aged ¹⁴C-atrazine residue mineralization varied between 2 and 8% for Belgian and between 1 and 2% for U.S. and Brazilian soil inoculum at 50% WHCmax but was increased under slurried conditions, accounting for 8-10% (Belgian soil), 2-7% (Brazilian soil), and 3% (American soil). The results show that an increased degradation of long-term aged ¹⁴C-labeled atrazine residues is possible by the transfer of atrazine-adapted soil microflora from different soils and regions to non-adapted soil.

  8. Electronic structure of herbicides: Atrazine and bromoxynil

    Science.gov (United States)

    Novak, Igor; Kovač, Branka

    2011-06-01

    The electronic structures of herbicides atrazine and bromoxynil have been investigated by UV photoelectron spectroscopy (UPS), quantum chemical calculations and comparison with X-ray diffraction, molecular docking and molecular dynamics studies. Their electronic and molecular structures are discussed in the context of their biological activity. This is the first report which correlates the molecular mechanism of biological activity of these herbicides with their experimentally determined electronic and molecular structures.

  9. PC clusters at CERN's PC farm

    CERN Multimedia

    Patrice Loïez

    2001-01-01

    These Linux-based PC clusters are mainly used for batch and interactive data processing. When the LHC starts operation in 2008, it will produce enough data every year to fill a stack of CDS 20 km tall, so high quality processing is required. To further facilitate this the LHC Computing Grid (LCG) has been set up to share processing power between facilities around the world.

  10. A PC based thin film dosimeter system

    DEFF Research Database (Denmark)

    Miller, A.; Hargittai, P.; Kovacs, A.

    2000-01-01

    A dosimeter system based on the Riso B3 dosimeter film, an office scanner for use with PC and the associated software is presented. The scanned image is analyzed either with standard software (Paint Shop Pro 5 or Excel) functions or with the computer code "Scanalizer" that allows presentation...

  11. Evaluation of Crops Sensitivity to Atrazine Soil Residual

    Directory of Open Access Journals (Sweden)

    E Izadi

    2012-02-01

    Full Text Available Abstract In order to study the sensitivity of 9 crops to atrazine soil residual, two separate experiments were conducted in field and greenhouse conditions. First experiment was conducted in a field with treated soil by atrazine based on split plot and the results evaluated in greenhouse conditions. Treatments in the field experiment included two organic manure application rates (0 and 50 t/ha as main plots and 2 atrazine application rates (2 and 4 kg/ha atrazine a.i. as sob plots. After corn harvesting soil was sampled at 0-15 cm surface layer in each plots in 15 points, after mixing the samples. Wheat, barley, sugar beet, pea, lens and colza planted in pots at greenhouse. Second experiment conducted in greenhouse conditions for evaluation of atrazine soil residual in completely randomized design. Treatments included atrazine soil residual concentrations (0, 0.2, 0.5, 1, 5, 10 and 15 mg/kg soil and crops included wheat, barley, sugar beet, pea, lens, rape, bean and tomato. Results showed that atrazine residue had no effect on crops growth in field experiment treated with atrazine. It seems that atrazine residue in filed soil is lower that its damage threshold for crops or maybe for its fast removal in field than in control conditions. But in bioassay experiment (greenhouse experiment crops response to atrazine residues were different. Results showed that onion and pea were most susceptible ant tolerant crops between studied species and based of ED50 parameter the other crops tolerance to total residue ranked as: pea< bean< lentil< sugar beet< tomato< barley< wheat< rape< onion. Keywords: Atrazine residue, Pea, Bean, Lentil, Sugar beet, Barley, Wheat, Rape, Tomato

  12. The PC graphics handbook

    CERN Document Server

    Sanchez, Julio

    2003-01-01

    Part I - Graphics Fundamentals PC GRAPHICS OVERVIEW History and Evolution Short History of PC Video PS/2 Video Systems SuperVGA Graphics Coprocessors and Accelerators Graphics Applications State-of-the-Art in PC Graphics 3D Application Programming Interfaces POLYGONAL MODELING Vector and Raster Data Coordinate Systems Modeling with Polygons IMAGE TRANSFORMATIONS Matrix-based Representations Matrix Arithmetic 3D Transformations PROGRAMMING MATRIX TRANSFORMATIONS Numeric Data in Matrix Form Array Processing PROJECTIONS AND RENDERING Perspective The Rendering Pipeline LIGHTING AND SHADING Lightin

  13. Leo II PC

    Data.gov (United States)

    Kansas Data Access and Support Center — LEO II is a second-generation software system developed for use on the PC, which is designed to convert location references accurately between legal descriptions and...

  14. Atrazine accumulation and toxic responses in maize Zea mays

    Institute of Scientific and Technical Information of China (English)

    Xiuying Li; Tong Wu; Honglin Huang; Shuzhen Zhang

    2012-01-01

    Atrazine accumulation,oxidative stress,and defense response in maize seedlings exposed to extraneous atrazine were studied.Accumulation of atrazine in maize increased with increasing exposure concentration.The abscisic acid (ABA) content was positively correlated with the atrazine concentrations in maize roots and shoots (p < 0.05).Hydroxyl radical (·OH) in maize was determined in vivo with electron paramagnetic resonance spectroscopy.Its intensity was positively correlated with atrazine concentration in roots and shoots (p < 0.05),and higher level of ·OH generated in roots than in shoots corresponded to the major accumulation of atrazinein roots.Superoxide dismutase,peroxidase and catalase in roots were up-regulated by atrazine exposure at 1 mg/L compared to the control and malondialdehyde content in roots was enhanced when atrazine exposure concentration reached 10 mg/L.These results suggested the exposure and accumulation of atrazine caused oxidative toxicity and antioxidant response in maize.

  15. Alternatives to atrazine for weed management in processing sweet corn

    Science.gov (United States)

    Atrazine has been the most widely used herbicide in North American processing sweet corn for decades; however, increased restrictions in recent years have reduced or eliminated atrazine use in certain production areas. The objective of this study was to identify the best stakeholder-derived weed man...

  16. Organic polymers for the reduction of atrazine concentration in water

    NARCIS (Netherlands)

    Mohd Amin, M.F.; Scherrenberg, S.M.; Rietveld, L.C.

    2012-01-01

    This study aims to investigate the ability of organic polymers of reducing atrazine concentration in water and the mechanism involved. Experimental studies carried out with two pre-selected cationic polymers to study the removal of atrazine from demin water. Preliminary results indicate that a reduc

  17. Introduction of Atrazine-Degrading Pseudomonas SP. Strain ADP to Enhance Phytoremediation of Atrazine

    Science.gov (United States)

    Atrazine (ATR) has been widely applied in the US Midwestern states. Public health and ecological concerns have been raised about contamination of surface and ground water by ATR and its chlorinated metabolites, due to their toxicity and potential carcinogenic or endocrinology effects. Phytoremediati...

  18. EFFECTS OF ATRAZINE AND AN ATRAZINE METABOLITE MIXTURE ON DIFFERENTIATED MAMMARY EPITHELIAL CELL MILK PROTEIN PRODUCTION IN CULTURE

    Science.gov (United States)

    Effects of Atrazine and an Atrazine Metabolite Mixture on Differentiated Mammary Epithelial Cell Milk Protein Production in CultureE.P. Hines, R. Barbee, M. Blanton, M.S. Pooler, and S.E. Fenton. US EPA, ORD/NHEERL, RTD, RTP, NC, 27711, USA.Previous studies have ...

  19. atz gene expressions during atrazine degradation in the soil drilosphere.

    Science.gov (United States)

    Monard, C; Martin-Laurent, F; Devers-Lamrani, M; Lima, O; Vandenkoornhuyse, P; Binet, F

    2010-02-01

    One of the various ecosystemic services sustained by soil is pollutant degradation mediated by adapted soil bacteria. The pathways of atrazine biodegradation have been elucidated but in situ expression of the genes involved in atrazine degradation has yet to be demonstrated in soil. Expression of the atzA and atzD genes involved in atrazine dechlorination and s-triazine ring cleavage, respectively, was investigated during in situ degradation of atrazine in the soil drilosphere and bulked samples from two agricultural soils that differed in their ability to mineralize atrazine. Interestingly, expression of the atzA gene, although present in both soils, was not detected. Atrazine mineralization was greatest in Epoisses soil, where a larger pool of atzD mRNA was consistently measured 7 days after atrazine treatment, compared with Vezin soil (146 vs. 49 mRNA per 10(6)16S rRNA, respectively). Expression of the atzD gene varied along the degradation time course and was profoundly modified in soil bioturbated by earthworms. The atzD mRNA pool was the highest in the soil drilosphere (casts and burrow-linings) and it was significantly different in burrow-linings compared with bulk soil (e.g. 363 vs. 146 mRNA per 10(6)16S rRNA, 7 days after atrazine treatment in Epoisses soil). Thus, consistent differences in atrazine mineralization were demonstrated between the soil drilosphere and bulk soil. However, the impact of bioturbation on atrazine mineralization depended on soil type. Mineralization was enhanced in casts, compared with bulk soil, from Epoisses soil but in burrow-linings from Vezin soil. This study is the first to report the effects of soil bioturbation by earthworms on s-triazine ring cleavage and its spatial variability in soil.

  20. The effects of the herbicide atrazine on freshwater snails.

    Science.gov (United States)

    Gustafson, Kyle D; Belden, Jason B; Bolek, Matthew G

    2015-07-01

    Atrazine has been shown to affect freshwater snails from the subcellular to community level. However, most studies have used different snail species, methods, endpoints, and atrazine exposure concentrations, resulting in some conflicting results and limiting our understanding. The goal of this study was to address these concerns by (1) investigating the acute and chronic effects of atrazine on four species of freshwater snails (Biomphalaria glabrata, Helisoma trivolvis, Physa acuta, and Stagnicola elodes) using the same methods, endpoints, and concentrations, and (2) summarizing the current literature pertaining to the effects of atrazine on freshwater snails. We conducted a 48 h acute toxicity test with an atrazine concentration higher than what typically occurs in aquatic environments (1000 µg/L). Additionally, we exposed snails to environmentally relevant atrazine concentrations (0, 0.3, 3, and 30 µg/L) for 28 days and assessed snail survival, growth, and reproduction. We also summarized all known literature pertaining to atrazine effects on freshwater snails. The literature summary suggests snails are often affected by environmentally relevant atrazine concentrations at the subcellular and cellular levels. These effects are typically not transitive to effects on survival, growth, or reproduction at the same concentrations. Our acute exposures corroborate the general trend of no direct effect on snail populations as atrazine did not directly affect the survival of any of the four snail species. Similarly, environmentally relevant concentrations did not significantly affect the survival, growth, or reproduction of any snail species. These results indicate that, in the absence of other possible stressors, the direct effects of environmentally relevant atrazine concentrations may not be realized at the snail population level.

  1. Building the perfect PC

    CERN Document Server

    Thompson, Robert Bruce

    2006-01-01

    This popular Build-It-Yourself (BIY) PC book covers everything you want to know about building your own system: Planning and picking out the right components, step-by-step instructions for assembling your perfect PC, and an insightful discussion of why you'd want to do it in the first place. Most big brand computers from HP, Dell and others use lower-quality components so they can meet their aggressive pricing targets. But component manufacturers also make high-quality parts that you can either purchase directly, or obtain through distributors and resellers. Consumers and corporations

  2. Contribution of ethylamine degrading bacteria to atrazine degradation in soils.

    Science.gov (United States)

    Smith, Daniel; Crowley, David E

    2006-11-01

    Bacterial communities that cooperatively degrade atrazine commonly consist of diverse species in which the genes for atrazine dechlorination and dealkylation are variously distributed among different species. Normally, the first step in degradation of atrazine involves dechlorination mediated by atzA, followed by stepwise dealkylation to yield either N-ethylammelide or N-isopropylammelide. As the liberated alkylamine moieties are constituents of many organic molecules other than atrazine, it is possible that a large number of alkylamine-degrading bacteria other than those previously described might contribute to this key step in atrazine degradation. To examine this hypothesis, we isolated 82 bacterial strains from soil by plating soil water extracts on agar media with ethylamine as a sole carbon source. Among the relatively large number of isolates, only 3 were able to degrade N-ethylammelide, and in each case were shown to carry the atzB gene and atzC genes. The isolates, identified as Rhizobium leguminosarum, Flavobacterium sp., and Arthrobacter sp., were all readily substituted into an atrazine-degrading consortium to carry out N-ethylammelide degradation. The distribution of these genes among many different species in the soil microbial population suggests that these genes are highly mobile and over time may lead to generation of various atrazine-degrading consortia.

  3. Equations of atrazine transfer from agricultural land to surface water

    Science.gov (United States)

    Cann, C.

    1995-08-01

    As atrazine, the most widely used herbicide in agriculture, makes problems for water supply, the Cemagref study its transfer from lands to surface water. On a small basin of central Brittany, soil and water contents of atrazine have been monitored from 1991 to 1994. Data show that atrazine content of the top layer of soil decreases slowly after spreading. Degradation works more than leaching for this decrease. There is always atrazine in the water of the stream at the outlet of the basin. The concentration of atrazine in water increase sharply in every flood and then decrease slowly. The maximum level of concentration in each flood is very well correlated with the ratio of maximum discharge to the base flow. It means that quick superficial flow of water is the most contaminated water. It brings most of the total flow of atrazine which can be measured in the stream. However, this flow represent only a very small part of the spread atrazine on the basin: less than 1%.

  4. Simulation study on vertical transport of atrazine in soil column

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A simulation experiment on vertical transport of herbicide atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) in soil column was conducted using lysimeter system. The atrazine concentrations in leaching water and soil samples in column at 8 layers with 10 cm thick of each layer were detected by high-performance liquid chromatography. The results show total atrazine amount in leaching water increases nonlinearly with the leaching time and the herbicide application rate, and the atrazine concentrations in column soil decrease with the vertical depth after water leaching. The distribution of atrazine mass in the system after 154 days were that among the applied atrazine, 0.3 % is out through leaching water, 1% is methanol extractable residues in soil, 46 % is methanol nonextractable residues in soil, and 52 % is other loss (including volatilization and degradation). The study indicates movement of atrazine in agriculture soil may not only have relation to the properties of herbicide, but also to the herbicide application history.

  5. Simulation study on vertical transport of atrazine in soil column

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A simulation experiment on vertical transport of herbicide atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) in soil column was conducted using lysimeter system. The atrazine concentrations in leaching water and soil samples in column at 8 layers with 10 cm thick of each layer were detected by high-performance liquid chromatography. The results show total atrazine amount in leaching water increases nonlinearly with the leaching time and the herbicide application rate, and the atrazine concentrations in column soil decrease with the vertical depth after water leaching. The distribution of atrazine mass in the system after 154 days were that among the applied atrazine, 0.3 % is out through leaching water, 1% is methanol extractable residues in soil, 46 % is methanol nonextractable residues in soil, and 52 % is other loss (including volatilization and degradation). The study indicates movement of atrazine in agriculture soil may not only have relation to the properties of herbicide, but also to the herbicide application history.

  6. Troubleshoot PC problems yourself

    CERN Document Server

    Price, Anthony

    2011-01-01

    Most tasks on a modern PC are within the abilities of the ordinary user: more D-I-Y than Hi-Tech. and can be carried out with a single screwdriver and standard software tools. Get a kick-start with this little book which will give you just enough to get you going...

  7. Sorption, Transport and Transformation of Atrazine in Soils,Minerals and Composts: A Review

    Institute of Scientific and Technical Information of China (English)

    A.MUDHOO; V.K.GARG

    2011-01-01

    Atrazine is a widely used herbicide for controlling weeds on both agricultural and nonagricultural land, which is equally detected in water supplies beyond safe concentrations. Although the presence of atrazine metabolites is an indication of herbicide degradation,some of them still exhibit toxicity, greater water solubility and weaker interaction with soil components than atrazine. Hence,studies with atrazine in the environment are of interest because of its potential to contaminate drinking water sources. Data on atrazine availability for transport, plant uptake, and microbial degradation and mineralization are therefore required to perform more comprehensive and realistic environmental risk assessments of its environmental fate. This review presents an account of the sorption-desorption phenomenon of atrazine on soil and other sorbents by revisiting the several mechanisms of atrazine-sorbent binding reported in the literature. The retention and transport of atrazine in soils; the influence of organic matter on atrazine sorption; the interactions of atrazine with humic substances, atrazine uptake by plants, atrazine bioccumulation and microbial degradation; atrazine transformation in composting environments; and finally atrazine removal by biosorption are discussed.

  8. Seletividade do atrazine à cultura do milheto (Pennisetum glaucum Atrazine selectivity in pearl millet (Pennisetum glaucum

    Directory of Open Access Journals (Sweden)

    H.A. Dan

    2010-01-01

    Full Text Available O milheto é uma espécie de destaque entre aquelas cultivadas em sucessão na região dos cerrados brasileiros. Embora o herbicida atrazine apresente potencial para ser utilizado nessa cultura, pouco tem sido feito para determinar a suscetibilidade dessa espécie em função do seu estádio de desenvolvimento no momento de aplicação. Objetivou-se com este trabalho avaliar a seletividade do herbicida atrazine à cultura do milheto (Pennisetum glaucum, determinando a dosagem máxima de aplicação e os estádios da cultura que apresentem menor sensibilidade. Foram realizados dois ensaios em casa de vegetação, onde se determinou primeiramente a seletividade do herbicida para os cultivares ADR-300, ADR-500 e ADR-7010. Posteriormente, o cultivar ADR-500 foi avaliado em condições de dose-resposta do atrazine, em função do estádio fenológico de desenvolvimento. Este experimento foi realizado no delineamento inteiramente casualizado, em esquema fatorial 5 x 3, com quatro repetições, correspondendo a cinco doses de atrazine: 0; 0,5; 1,5; 2,5 e 4,0 kg de i.a. ha-1, aplicadas em três estádios de crescimento do milheto (duas, quatro e oito folhas expandidas. O cultivar ADR-500 apresentou a maior suscetibilidade entre os avaliados. Aplicações realizadas nos estádios mais precoces de crescimento do milheto promoveram os maiores níveis de intoxicação, redução do número de afílhos e do acúmulo de biomassa seca da parte aérea. Esses resultados intensificaram-se com o incremento da dose de atrazine. Com relação à massa da espiga, doses inferiores a 1,5 kg ha-1 não prejudicaram significativamente essa variável, independentemente do estádio de aplicação. É possível concluir que doses inferiores a 1,5 kg ha-1 de atrazine podem ser usadas de forma segura na cultura do milheto quando as plantas apresentarem quatro ou mais folhas no momento da aplicação.Pearl millet is an important species cultivated in succession in the Brazilian

  9. Treatment of atrazine by integrating photocatalytic and biological processes.

    Science.gov (United States)

    Chan, C Y; Tao, S; Dawson, R; Wong, P K

    2004-09-01

    This research examines the degradation of atrazine by photocatalytic oxidation (PCO) under different experimental conditions. Deisopropylatrazine, deethylatrazine and deethyldeisopropylatrazine were formed as major intermediates based on gas chromatography-mass spectrometry. The reaction mixture was found to be toxic towards two bioassays, i.e. the Microtox and amphipods survival tests even when atrazine was completely degraded by PCO within 2 h under optimized conditions. The results indicate that adding H2O2 could significantly enhance the degradation of atrazine by PCO. Ammeline, ammelide and cyanuric acid (CA) became the major intermediates/products as detected by high performance liquid chromatography from 6th to the 40th h of PCO treatment. After 72 h PCO treatment, only CA was detectable in the reaction mixture. Further degradation of CA was carried out by a newly isolated CA-degrading bacterium, Sphingomonas capsulata. The photochemical pretreatment integrated with microbial degradation lead to the complete degradation and detoxification of atrazine.

  10. Annual county atrazine use estimates for agriculture, 1992-2007

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set contains annual county-level estimates of total atrazine use on 16 agricultural crops and four agricultural land uses between 1992 and 2007. For each...

  11. ADSORPTION OF ATRAZINE ON SELECTED VERTISOLS AND ALFISOLS

    Directory of Open Access Journals (Sweden)

    K.V. Naga Madhuri

    2012-08-01

    Full Text Available Adsorption of atrazine was studied on two Vertisols and two Alfisols varying in their physico-chemical properties. Soils were equilibrated with various concentrations of atrazine using batch techniques.Adsorption affinity for atrazine was approximated by Freundlich constant (Kf, which is a measure of the strength ordegree of adsorption. Kdvalues were calculated for atrazine despite some non-linearity in adsorption on bothVertisols and Alfisols. The Kdvalues are greater for Vertisols than Alfisols and increased with organic carboncontent. Correlations were worked out between extent of adsorption and soil properties and were positivelycorrelated with organic carbon (r = 0.688, clay content ( r = 0.712 and clay + organic carbon (r = 0.708. KOCvalues were calculated taking into account the organic carbon content for both Vertisols and Alfisols

  12. Architecture of Trusted PC

    Institute of Scientific and Technical Information of China (English)

    WU Shuhua; ZHU Yuefei

    2006-01-01

    This paper, focusing on the trusted computing group's standards, explained the key concept of trusted computing and provided the architecture of trusted PC. It built trust bottom-up by starting with trusted hardware and adding layers of trusted software. It is a system-level solution available to all applications running on the member platforms. This solution reduces the security burden on applications and thus simplifies application programming.

  13. Theoretical Researches on the Recognizing Characteristics of Atrazine Imprinted Polymers with Different Functional Monomers

    Institute of Scientific and Technical Information of China (English)

    LIU Jun-Bo; SUN Jia-Ni; TANG Shan-Shan; CHEN Kai-Yin; JIN Rui-Fa

    2012-01-01

    As a widely used herbicide, the threat of atrazine to both environment and health of people has become the focus. Therefore, the research and analysis of atrazine are getting more important. In this work, the MIT was used to detect atrazine theoretically. Atrazine was taken as a template molecule. MAA, MMA and TFMAA were taken as the functional monomers, respectively. The geometry optimization, the nature of hydrogen bonds, the NBO charge, and the binding energies of the imprinted molecule with the functional monomers were investigated at the B3LYP/6-31g(d,p) level. Results indicated that atrazine had the strongest interaction with TFMAA. When the ratio of atrazine and TFMAA was 1:6, the amount of H-bond formed from atrazine and TFMAA was the largest. Moreover, TFMAA owned the largest binding energy with atrazine while MMA owned the smallest. The study is helpful to interpret experiment phenomena of molecular imprinting and select better functional monomers.

  14. Evaluation of atrazine degradation applied to different energy systems.

    Science.gov (United States)

    Moreira, Ailton J; Pinheiro, Bianca S; Araújo, André F; Freschi, Gian P G

    2016-09-01

    Atrazine is an herbicide widely used in crops and has drawn attention due to potential pollution present in soil, sediment, water, and food. Since conventional methods are not potentially efficient to persistent degradation of organic compounds, new technology has been developed to remove them, especially practices utilizing advanced oxidation processes (AOPs). This work aims to evaluate the use of different energies (ultraviolet (UV), microwaves (MW), and radiations (MW-UV)) to the herbicide atrazine through the process of photo-oxidation. These systems found degradation rates of around 12 % (UV), 28 % (MW), and 83 % (MW-UV), respectively, with time intervals of 120 s. After the photolytic processes, the samples were analyzed at a wavelength scanning the range of 190 to 300 nm, where the spectral analysis of the signal was used to evaluate the degradation of atrazine and the appearance of some other peaks (degradation products). The spectrum evaluation resulting from photolytic processes gave rise to a new signal which was confirmed by chromatography. This spectrum indicated the possible pathway of atrazine degradation by the process of photolytic MW-UV, generating atrazine-2-hydroxy, atrazine-desethyl-2-hidroxy, and atrazine-desisopropyl-2-hydroxy. The process indicated that in all situations, chloride was present in the analytic structure and was substituted by a hydroxyl group, which lowered the toxicity of the compound through the photolytic process MW-UV. Chromatographic analysis ascertained these preliminary assessments using spectrophotometry. It was also significantly observed that the process can be optimized by adjusting the pH of the solution, which was evident by an improvement of 10 % in the rate of degradation when subjected to a pH solution equal to 8.37.

  15. Toxicity and physical properties of atrazine and its degradation products: A literature survey

    Energy Technology Data Exchange (ETDEWEB)

    Pugh, K.C.

    1994-10-01

    The Tennessee Valley Authority`s Environmental Research Center has been developing a means of detoxifying atrazine waste waters using TiO{sub 2} photocatalysis. The toxicity and physical properties of atrazine and its degradation products will probably be required information in obtaining permits from the United States Environmental Protection Agency for the demonstration of any photocatalytic treatment of atrazine waste waters. The following report is a literature survey of the toxicological and physical properties of atrazine and its degradation products.

  16. 76 FR 25281 - Atrazine, Chloroneb, Chlorpyrifos, Clofencet, Endosulfan, et al.; Proposed Tolerance Actions

    Science.gov (United States)

    2011-05-04

    ... AGENCY 40 CFR Part 180 Atrazine, Chloroneb, Chlorpyrifos, Clofencet, Endosulfan, et al.; Proposed..., modify certain tolerances for atrazine, establish tolerances for endosulfan, and make minor revisions to..., EPA is proposing to modify certain tolerances for the herbicide atrazine. In addition, EPA...

  17. Atrazine Biodegradation in a Cisne Soil Exposed to a Major Spill

    Science.gov (United States)

    Conventional soil tests, culture-based microbial methods, and the novel method of 15N-DNA stable isotope probing (SIP) were employed to illustrate atrazine biodegradation as related to the physiochemical properties of an atrazine-exposed Cisne soil. This soil exhibited enhanced atrazine degradation...

  18. Radiolytic degradation of atrazine aqueous solution containing humic substances.

    Science.gov (United States)

    Basfar, A A; Mohamed, K A; Al-Abduly, A J; Al-Shahrani, A A

    2009-03-01

    Degradation of atrazine herbicide in humic substances (HS) aqueous solutions and distilled water solutions was investigated on a laboratory scale upon gamma-irradiation from a (60)Co source. In addition, the effect of ionizing radiation on the atrazine residues removal efficiency was investigated in relation to degradation of by-products. gamma-Irradiation experiments were carried out for three targeted concentrations (i.e. 0.464, 2.318 and 4.636 microM) with doses over the range 0.1-60 kGy. The initial concentration of herbicide, scavengers and irradiation doses play a significant role in the degradation efficiency as shown by decay constants of atrazine residues. gamma-Radiolysis showed that atrazine exhibited high degradation percentages at low absorbed doses in HS aqueous solutions compared to distilled water solutions. Absorbed doses from 0.6 to 21 kGy and from 6 to 72 kGy at a dose rate of 14.52 kGyh(-1) achieved 90% degradation for atrazine with initial concentrations over the range 0.464-4.636 microM in humic and distilled water solutions, respectively. The radiolytic degradation by-products and their mass balances were qualitatively determined with good confidence using gas chromatography/quadruple mass spectrometry (GC/MS) with electron impact ionization (EI(+)) mode.

  19. PC Inspector File Recovery

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    PC Inspector File Recovery是一个数据修复软件,它支持Fat12/16/32和NTFS文件系统。3.x的新特点:1,即使在引导区或FAT被删除或损坏的情况下,也能自动寻找到驱动器(对NTFS系统不具有该功能)。2.按照原始的时间和日期重新恢复文件。3.支持恢复文件的储存及网络驱。

  20. Demand for PC Increases Rapidly

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ PC (polycarbonate) is an engineering thermoplastic with excellent comprehensive properties. It has the advantages of great strength, high toughness, good heat resistance,light weight, excellent workability and stable color and is therefore extensively used in several sectors:automotive, electronic/electric,construction, office equipment,packaging, sports ware, medical/health care and household utensils.PC can also be used to make PC copolymers or alloyed with other monomers or resins to improve its properties.

  1. Photo-assisted electrochemical degradation of the commercial herbicide atrazine.

    Science.gov (United States)

    Malpass, G R P; Miwa, D W; Gomes, L; Azevedo, E B; Vilela, W F D; Fukunaga, M T; Guimarães, J R; Bertazzoli, R; Machado, S A S; Motheo, A J

    2010-01-01

    This paper presents a degradation study of the pesticide atrazine using photo-assisted electrochemical methods at a dimensionally stable anode (DSA(®)) of nominal composition Ti/Ru(0.3)Ti(0.7)O(2) in a prototype reactor. The effects of current density, electrolyte flow-rate, as well as the use of different atrazine concentrations are reported. The results indicate that the energy consumption is substantially reduced for the combined photochemical and electrochemical processes when compared to the isolated systems. It is observed that complete atrazine removal is achieved at low current densities when using the combined method, thus reducing the energy required to operate the electrochemical system. The results also include the investigation of the phytotoxicity of the treated solutions.

  2. Dielectric barrier discharge plasma induced degradation of aqueous atrazine.

    Science.gov (United States)

    Feng, Jingwei; Jiang, Lin; Zhu, Dan; Su, Kuizu; Zhao, Dayong; Zhang, Jibiao; Zheng, Zheng

    2016-05-01

    Degradation of herbicide atrazine in aqueous solution was investigated using a plate type dielectric barrier discharge (DBD) plasma reactor. DBD plasma was generated at the gas-liquid interface of the formed water film. At discharge time of 14 min, atrazine was degradated effectively with a degradation rate of 99 % at the discharge power of 200 W. The experimental data fitted well with first-order kinetics and the energy efficiency for 90 % degradation of atrazine (G value) was calculated, obtaining a rate constant of 0.35 min(-1) and a G value of 1.27 × 10(-10) mol J(-1) (98.76 mg kW(-1) h(-1)) at a discharge power of 200 W, respectively. The addition of Fe(2+) increased the rate constant and G value dramatically, and a significant decrease of the rate constant and G value was observed with the addition of radical scavengers (tert-butyl alcohol, isopropyl alcohol, or Na2CO3). The generated aqueous O3 and H2O2 were determined, which promoted the degradation of herbicide atrazine. Dechlorination was observed and the experimentally detected Cl(-) was 1.52 mg L(-1) at a discharge time of 14 min. The degradation intermediates of atrazine were detected by means of liquid chromatography-mass spectrometry; dechlorination, hydroxylation, dealkylation, and alkyl oxidation processes were involved in the degradation pathways of atrazine.

  3. Estimation of the Potential for Atrazine Transport in a Silt Loam Soil

    Science.gov (United States)

    Eckhardt, D.A.V.; Wagenet, R.J.

    1996-01-01

    The transport potential of the herbicide atrazine (2-chloro-4-ethyl-6-isopropyl-s-triazine) through a 1-meter-thick root zone of corn (Zea mays L.) in a silty-loam soil in Kansas was estimated for a 22-year period (1972-93) using the one-dimensional water-flow and solute-transport model LEACHM. Results demonstrate that, for this soil, atrazine transport is directly related to the amount and timing of rain that follows spring applications of atrazine. Two other critical transport factors were important in wet years - [1] variability in atrazine application rate, and [2] atrazine degradation rates below the root zone. Results demonstrate that the coincidence of heavy rain soon after atrazine application can cause herbicide to move below the rooting zone into depths at which biodegradation rates are assumed to be low but are often unknown. Atrazine that reaches below the rooting zone and persists in the underlying soil can subsequently be transported into ground water as soil water drains, typically after the growing season. A frequency analysis of atrazine concentrations in subsurface drainage, combined with field data, demonstrates the relative importance of critical transport factors and confirms a need for definitive estimates of atrazine-degradation rates below the root zone. The analysis indicates that periodic leaching of atrazine can be expected for this soil when rainfall that exceeds 20 cm/mo coincides with atrazine presence in soil.

  4. Chemical modification and degradation of atrazine in Medicago sativa through multiple pathways.

    Science.gov (United States)

    Zhang, Jing Jing; Lu, Yi Chen; Yang, Hong

    2014-10-08

    Atrazine is a member of the triazine herbicide family intensively used to control weeds for crop production. In this study, atrazine residues and its degraded products in alfalfa (Medicago sativa) were characterized using UPLC-TOF-MS/MS. Most of atrazine absorbed in plants was found as chemically modified derivatives like deisopropylated atrazine (DIA), dehydrogenated atrazine (DHA), or methylated atrazine (MEA), and some atrazine derivatives were conjugated through different functional groups such as sugar, glutathione, and amino acids. Interestingly, the specific conjugates DHA+hGSH (homoglutathione) and MEA-HCl+hGSH in alfalfa were detected. These results suggest that atrazine in alfalfa can be degraded through different pathways. The increased activities of glycosyltransferase and glutathione S-transferase were determined to support the atrazine degradation models. The outcome of the work uncovered the detailed mechanism for the residual atrazine accumulation and degradation in alfalfa and will help to evaluate whether the crop is suitable to be cultivated in the atrazine-polluted soil.

  5. Optimization and kinetics studies on biodegradation of atrazine using mixed microorganisms

    Directory of Open Access Journals (Sweden)

    N. Debasmita

    2013-09-01

    Full Text Available In this work, degradation of atrazine was carried out in batch reactors using mixed microorganisms obtained from pharmaceutical wastewater sludge. The effects of process parameters like pH, temperature, inoculum concentration, and agitation speed on atrazine degradation were studied and optimized using response surface methodology (RSM. The optimum condition for the maximum degradation of atrazine was pH – 6.7, temperature – 29.3 °C, inoculum concentration – 5%, and agitation speed – 137 rpm. At these conditions, the effect of atrazine concentration was studied. From the results, it was found that increase in atrazine concentration decreases the degradation efficiency. The maximum atrazine degradation was found to be 94.4%. Various cell growth models and substrate inhibition models were used to describe the atrazine degradation kinetics. From the results, it was found that Haldane model fits the data well with R2 value of 0.9001.

  6. Photolytic treatment of atrazine-contaminated water: products, kinetics, and reactor design.

    Science.gov (United States)

    Ye, Xuejun; Chen, Daniel; Li, Kuyen; Wang, Bin; Hopper, Jack

    2007-08-01

    This study investigates the products, kinetics, and reactor design of atrazine photolysis under 254-nm ultraviolet-C (UVC) irradiation. With an initial atrazine concentration of 60 microg/L (60 ppbm), only two products remain in detectable levels. Up to 77% of decomposed atrazine becomes hydroxyatrazine, the major product. Both atrazine and hydroxyatrazine photodecompose following the first-order rate equation, but the hydroxyatrazine photodecomposition rate is significantly slower than that of atrazine. For atrazine photodecomposition, the rate constant is proportional to the square of UVC output, but inversely proportional to the reactor volume. For a photochemical reactor design, a series of equations are proposed to calculate the needed UVC output power, water treatment capacity, and atrazine outlet concentration.

  7. Spatial distribution of enhanced atrazine degradation across northeastern Colorado cropping systems.

    Science.gov (United States)

    Shaner, Dale; Stromberger, Mary; Khosla, Raj; Helm, Alan; Bosley, Bruce; Hansen, Neil

    2011-01-01

    Reports of enhanced atrazine degradation and reduced residual weed control have increased in recent years, sparking interest in identifying factors contributing to enhanced atrazine degradation. The objectives of this study were to (i) assess the spatial distribution of enhanced atrazine degradation in 45 commercial farm fields in northeastern Colorado (Kit Carson, Larimer, Logan, Morgan, Phillips, and Yuma counties) where selected cultural management practices and soil bio-chemo-physical properties were quantified; (ii) utilize Classification and Regression Tree (CART) Analysis to identify cultural management practices and (or) soil bio-chemophysical attributes that are associated with enhanced atrazine degradation; and (iii) translate our CART Analysis into a model that predicts relative atrazine degradation rate (rapid, moderate, or slow) as a function of known management practices and (or) soil properties. Enhanced atrazine degradation was widespread within a 300-km radius across northeastern Colorado, with approximately 44% of the fields demonstrating rapid atrazine degradation activity (laboratory-based dissipation time halflife [DT50] degradation rates occurred in fields that received the most frequent atrazine applications. Classification and Regression Tree Analysis resulted in a prediction model that correctly classified soils with rapid atrazine DT50 80% of the time and soils with slow degradation (DT50 > 8 d) 62.5% of the time. Significant factors were recent atrazine use history, soil pH, and organic matter content. The presence/absence of atzC polymerase chain reaction (PCR) product was not a significant predictor variable for atrazine DT50. In conclusion, enhanced atrazine degradation is widespread in northeastern Colorado. If producers know their atrazine use history, soil pH, and OM content, they should be able to identify fields exhibiting enhanced atrazine degradation using our CART Model.

  8. Preparation of Bio-beads and Their Atrazine Degradation Characteristics

    Institute of Scientific and Technical Information of China (English)

    BI Hai-tao; ZHANG Lan-ying; LIU Na; ZHU Bo-lin

    2011-01-01

    Screened atrazine-mineralizing bacterium-Pseudomonas W4 was embedded inside an improved PVAH3BO3 embedment matrix to make bio-beads to degrade atrazine. The atrazine degradation characteristics were studied. The preparation procedure of bio-beads was as follows: (1) preparing a mixture of 100, 12.5, 10, 1.5 and 1 g/L PVA, bentonite(Ca), activated carbon powder, sodium alginate and centrifuged Pseudomonas W4 bacterium, respectively; (2) the mixture was dropped into a gently stirred cross linker solution(pH=6.7) and cured at 10 ℃ for 24 h.The optimal atrazine degradation conditions by bio-beads were as follows: pH=7, the auxiliary carbon source was glucose, and the concentration of glucose was greater than 325 mg/L. The bio-beads demonstrated stronger tolerance ability than the free microorganism to the increase of PCBs, hydrogen ion and hydroxide ion. SEM images show the uniform distribution of the microorganism inside bio-beads and the porous cross-linked structure of bio-beads which provides excellent mass transfer capacity.

  9. Modeling atrazine transport in soil columns with HYDRUS-1D

    Directory of Open Access Journals (Sweden)

    John Leju CELESTINO LADU

    2011-09-01

    Full Text Available Both physical and chemical processes affect the fate and transport of herbicides. It is useful to simulate these processes with computer programs to predict solute movement. Simulations were run with HYDRUS-1D to identify the sorption and degradation parameters of atrazine through calibration from the breakthrough curves (BTCs. Data from undisturbed and disturbed soil column experiments were compared and analyzed using the dual-porosity model. The study results show that the values of dispersivity are slightly lower in disturbed columns, suggesting that the more heterogeneous the structure is, the higher the dispersivity. Sorption parameters also show slight variability, which is attributed to the differences in soil properties, experimental conditions and methods, or other ecological factors. For both of the columns, the degradation rates were similar. Potassium bromide was used as a conservative non-reactive tracer to characterize the water movement in columns. Atrazine BTCs exhibited significant tailing and asymmetry, indicating non-equilibrium sorption during solute transport. The dual-porosity model was verified to best fit the BTCs of the column experiments. Greater or lesser concentration of atrazine spreading to the bottom of the columns indicated risk of groundwater contamination. Overall, HYDRUS-1D successfully simulated the atrazine transport in soil columns.

  10. Determination of the atrazine migration parameters in Vertisol

    Science.gov (United States)

    Raymundo-Raymundo, E.; Hernandez-Vargas, J.; Nikol'Skii, Yu. N.; Guber, A. K.; Gavi-Reyes, F.; Prado-Pano, B. L.; Figueroa-Sandoval, B.; Mendosa-Hernandez, J. R.

    2010-05-01

    The parameters of the atrazine migration in columns with undisturbed Vertisol sampled from an irrigated plot in Guanajuato, Mexico were determined. A model of the convection-dispersion transport of the chemical compounds accounting for the decomposition and equilibrium adsorption, which is widely applied for assessing the risk of contamination of natural waters with pesticides, was used. The model parameters were obtained by solving the inverse problem of the transport equation on the basis of laboratory experiments on the transport of the 18O isotope and atrazine in soil columns with an undisturbed structure at three filtration velocities. The model adequately described the experimental data at the individual selection of the parameters for each output curve. Physically unsubstantiated parameters of the atrazine adsorption and degradation were obtained when the parameter of the hydrodynamic dispersion was determined from the data on the 18O migration. The simulation also showed that the use of parameters obtained at water content close to saturation in the calculations for an unsaturated soil resulted in the overestimation of the leaching rate and the maximum concentration of atrazine in the output curve compared to the experimental data.

  11. Polyelectrolytes Ability in Reducing Atrazine Concentration in Water: Surface Effects

    NARCIS (Netherlands)

    Mohd Amin, M.F.; Heijman, S.G.J.; Lopes, S.I.C.; Rietveld, L.C.

    2014-01-01

    This paper reports on the direct ability of two positively charged organic polyelectrolytes (natural-based and synthetic) to reduce the atrazine concentration in water. The adsorption study was set up using multiple glass vessels with different polymer dosing levels followed by ultrafiltration with

  12. Veterinary antibiotic effects on atrazine degradation and soil microorganisms

    Science.gov (United States)

    Veterinary antibiotics (VAs) in manure applied to agricultural lands may change agrichemical degradation by altering soil microbial community structure or function. The objectives of this study were to investigate the influence of two VAs, sulfamethazine (SMZ) and oxytetracycline (OTC), on atrazine ...

  13. Qualification plan for the Genmod-PC computer program

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, R.B.; Wright, G.M.; Dunford, D.W.; Linauskas, S.H

    2002-07-01

    Genmod-PC is an internal dosimetry code that uses Microsoft Windows operating system, and that currently calculates radionuclide doses and intakes for an adult male. This report provides a plan for specifying the quality assurance measures that conform to the recommendations of the Canadian Standards Association, as well as AECL procedural requirements for a legacy computer program developed at AECL. (author)

  14. A Low Cost Sounding System Using PC and Stereo Equipment

    CERN Document Server

    Campbell, Joel F; Prasad, Narasimha S; Hodson, Wade D

    2011-01-01

    A system using a PC computer, speakers, and a microphone are used to measure distance or the speed of sound using a carrier modulated by pseudo random noise (PN)codes. This system can easily be built by students using computer and audio equipment commonly found in the lab or at home.

  15. Exploring bacterial community structure and function associated with atrazine biodegradation in repeatedly treated soils.

    Science.gov (United States)

    Fang, Hua; Lian, Jianjun; Wang, Huifang; Cai, Lin; Yu, Yunlong

    2015-04-09

    Substantial application of the herbicide atrazine in agriculture leads to persistent contamination, which may damage the succeeding crops and pose potential threats to soil ecology and environmental health. Here, the degradation characteristics of atrazine and dynamic change of soil bacterial community structure and function as well as their relations were studied during three repeated treatments at the recommended, double, and five-fold doses. The results showed that the degradation half-life of atrazine obviously decreased with increased treatment frequency. Soil microbial functional diversity displayed a variation trend of suppression-recovery-stimulation, which was associated with increased degradation rate of atrazine. 16S amplicon sequencing was conducted to explore bacterial community structure and correlate the genus to potential atrazine degradation. A total of seven potentially atrazine-degrading bacterial genera were found including Nocardioides, Arthrobacter, Bradyrhizobium, Burkholderia, Methylobacterium, Mycobacterium, and Clostridium. These bacterial genera showed almost complete atrazine degradation pathways including dechlorination, dealkylation, hydroxylation, and ring cleavage. Furthermore, the relative abundance of four of them (i.e., Nocardioides, Arthrobacter, Methylobacterium, and Bradyrhizobium) increased with treatment frequency and atrazine concentration, suggesting that they may participate in atrazine degradation during repeated treatments. Our findings reveal the potential relationship between atrazine degradation and soil bacterial community structure in repeatedly treated soils.

  16. [Efficiency of atrazine degradation by O3/H2O2].

    Science.gov (United States)

    Li, Shao-Feng; Liang, Yuan; Zhang, Rong-Quan; Ye, Fei

    2009-05-15

    The endocrine disrupter Atrazine was oxidized by O3/H2O2 system and the products were analyzed to assess the degradation efficiency of Atrazine. When it's initial content was 2 mg/L and O3 dosage was 7.5 mg/L, Atrazine was removed about 27.2% after 5 minutes. Under the same condition, H2O2/O3 molar ratio was 0.75, Atrazine maximum removal rate reached 96.5%, which suggested that Atrazine could be degraded by O3/H2O2 system effectively. Ion Chromatography (IC) analysis showed that concentrations of chloride and nitrate ions were increasing along with the Atrazine content decreasing. Gas Chromatography-Mass spectrometry (GC-MS) and Liquid Chromatography-Mass spectrometry chromatograms (LC-MS) analyzing illuminated the existence of de-ethyl-atrazine, de-isopropyl-atrazine and de-chloro-atrazine, which indicated the Atrazine could not be destroyed completely by O3/H2O2 system. Consequently, it should be combined with GAC (Granular Activated Carbon) or other techniques while used as primary treatment unit or emergency measure.

  17. Toxicity of atrazine and its bioaccumulation and biodegradation in a green microalga, Chlamydomonas mexicana.

    Science.gov (United States)

    Kabra, Akhil N; Ji, Min-Kyu; Choi, Jaewon; Kim, Jung Rae; Govindwar, Sanjay P; Jeon, Byong-Hun

    2014-11-01

    This study evaluated the toxicity of herbicide atrazine, along with its bioaccumulation and biodegradation in the green microalga Chlamydomonas mexicana. At low concentration (10 μg L(-1)), atrazine had no profound effect on the microalga, while higher concentrations (25, 50, and 100 μg L(-1)) imposed toxicity, leading to inhibition of cell growth and chlorophyll a accumulation by 22 %, 33 %, and 36 %, and 13 %, 24 %, and 27 %, respectively. Atrazine 96-h EC50 for C. mexicana was estimated to be 33 μg L(-1). Microalga showed a capability to accumulate atrazine in the cell and to biodegrade the cell-accumulated atrazine resulting in 14-36 % atrazine degradation at 10-100 μg L(-1). Increasing atrazine concentration decreased the total fatty acids (from 102 to 75 mg g(-1)) and increased the unsaturated fatty acid content in the microalga. Carbohydrate content increased gradually with the increase in atrazine concentration up to 15 %. This study shows that C. mexicana has the capability to degrade atrazine and can be employed for the remediation of atrazine-contaminated streams.

  18. Bioremediation strategies for removal of residual atrazine in the boreal groundwater zone.

    Science.gov (United States)

    Nousiainen, Aura O; Björklöf, Katarina; Sagarkar, Sneha; Nielsen, Jeppe Lund; Kapley, Atya; Jørgensen, Kirsten S

    2015-12-01

    Strategies for bioremediation of atrazine, a pesticide commonly polluting groundwater in low concentrations, were studied in two boreal nonagricultural soils. Atrazine was not mineralized in soil without bioremediation treatments. In biostimulation treatment with molasses, up to 52% of atrazine was mineralized at 10 °C, even though the degradation gene copy numbers did not increase. Incubations with radioactively labeled atrazine followed by microautoradiographic analysis revealed that bioremediation strategies increased the relative proportion of active degraders from 0.3 up to 1.9% of the total bacterial count. These results indicate that atrazine degradation might not solely be facilitated by atzA/trzN-atzB genes. In combined biostimulation treatment using citrate or molasses and augmentation with Pseudomonas citronellolis ADP or Arthrobacter aurescens strain TC1, up to 76% of atrazine was mineralized at 30 °C, and the atrazine degradation gene numbers increased up to 10(7) copies g(-1) soil. Clone libraries from passive samplers in groundwater monitoring wells revealed the presence of phylogenetic groups formerly shown to include atrazine degraders, and the presence of atrazine degradation genes atzA and atzB. These results show that the mineralization of low concentrations of atrazine in the groundwater zone at low temperatures is possible by bioremediation treatments.

  19. Isolation and characterization of novel atrazine-degrading microorganisms from an agricultural soil.

    Science.gov (United States)

    Vibber, Laurel L; Pressler, Michael J; Colores, Gregory M

    2007-06-01

    Six previously undescribed microorganisms capable of atrazine degradation were isolated from an agricultural soil that received repeated exposures of the commonly used herbicides atrazine and acetochlor. These isolates are all Gram-positive and group with microorganisms in the genera Nocardioides and Arthrobacter, both of which contain previously described atrazine degraders. All six isolates were capable of utilizing atrazine as a sole nitrogen source when provided with glucose as a separate carbon source. Under the culture conditions used, none of the isolates could utilize atrazine as the sole carbon and nitrogen source. We used several polymerase-chain-reaction-based assays to screen for the presence of a number of atrazine-degrading genes and verified their identity through sequencing. All six isolates contain trzN and atzC, two well-characterized genes involved in the conversion of atrazine to cyanuric acid. An additional atrazine-degrading gene, atzB, was detected in one of the isolates as well, yet none appeared to contain atzA, a commonly encountered gene in atrazine impacted soils and atrazine-degrading isolates. Interestingly, the deoxyribonucleic acid sequences of trzN and atzC were all identical, implying that their presence may be the result of horizontal gene transfer among these isolates.

  20. Atrazine degradation and residues distribution in two acid soils from temperate humid zone.

    Science.gov (United States)

    Mahía, J; Díaz-Raviña, M

    2007-01-01

    Mineralization of atrazine and formation of extractable and non-extractable "bound" residues were followed under laboratory conditions in two contrasting soils (organic C, texture, and atrazine application history) from northern Spain. The soils, a Humic Cambisol (MP) and a Gleyic Cambisol (G) were incubated with labeled atrazine (ring-13C atrazine) at field application dose and measurements were made at different time intervals during 3 mo. Fate and behavior of atrazine along the incubation showed different patterns between the two soils, the time taken for degradation of 50% (DT50) being 9 and 44 d for MP and G soils, respectively. In MP soil, with 40 yr of atrazine application and lower organic C and clay content, more than 89% of U-13C-atrazine added was mineralized after 12 wk, with most mineralization occurring within the first 2 wk. G soil, with 10 yr of atrazine application, exhibited a more progressive U-13C-atrazine mineralization, reaching 54% of initially added atrazine at 12 wk. Hydroxyatrazine and deisopropylatrazine were the metabolites founded in the extractable fraction, demonstrating that both chemical and biological processes are involved in atrazine degradation. Soil G showed during all the incubation times an extractable residues fraction greater than that in MP soil, indicating a high potential risk of soil and water contamination. Rapid microbial degradation through s-triazine ring cleavage was proposed to be the main decomposition pathway of atrazine for the two soils studied. Bound residues pool also differed notably between soils accounting for 9 and 41% of initially added atrazine, the higher values shown by soil with higher organic matter and clay content (G soil).

  1. Relationship between uptake capacity and differential toxicity of the herbicide atrazine in selected microalgal species

    Energy Technology Data Exchange (ETDEWEB)

    Weiner, Jeannette A.; DeLorenzo, Marie E.; Fulton, Michael H

    2004-06-10

    Microalgal species vary in their sensitivity to the triazine herbicide, atrazine. This study examined both atrazine uptake and cellular characteristics of microalgae to determine if either can be used to predict algal sensitivity. Standard toxicity tests were performed on five microalgal species, each representing a different algal division or habitat. Test species listed in order of increasing sensitivity were: Isochrysis galbana, Dunaliella tertiolecta, Phaeodactylum tricornutum, Pseudokirchneriella subcapitata, and Synechococcus sp. Each species was exposed to {sup 14}C-atrazine at its growth rate EC{sub 50} concentration (44-91 {mu}g/L). At five time-points over 96 h, samples were filtered to collect algae and washed with unlabeled atrazine to displace labeled atrazine loosely absorbed to the cell surface. Radioactivity present on filters and in the growth medium was measured by liquid scintillation counting. Relationships between algal species-sensitivity to atrazine and compound uptake, cell dry weight, cell volume, and cell surface area were determined by linear regression analysis. Cell size measurements (based on dry weight, biovolume, and surface area) were significantly correlated with atrazine uptake (R{sup 2}>0.45, P-value < 0.05). There was a significant correlation between atrazine uptake and species-sensitivity to atrazine (R{sup 2}=0.5413, P-value = 0.0012). These results indicate that smaller cells with greater surface area to volume ratios will incorporate more atrazine, and in general, will be more sensitive to atrazine exposure. However, I. galbana, with small cell size and relatively high atrazine uptake was the least sensitive species tested. This species and others may have mechanisms to compensate for atrazine stress that make predicting responses of microalgal communities difficult.

  2. In vivo genotoxicity evaluation of atrazine and atrazine-based herbicide on fish Carassius auratus using the micronucleus test and the comet assay.

    Science.gov (United States)

    Cavas, Tolga

    2011-06-01

    Atrazine is a selective triazine herbicide used to control broadleaf and grassy weeds mainly in corn, sorghum, sugarcane, pineapple, and other crops, and in conifer reforestation planting fields. It has been showed that atrazine is one of the most frequently detected pesticides in agricultural streams and rivers, over the past two decades. Although the toxic properties of atrazine are well known, the data on the genotoxic effects of atrazine on aquatic organisms are rather scarce. Thus, in the present study we aimed to evaluate the genotoxic effects of atrazine and an atrazine-based herbicide (Gesaprim®) on a model fish species Carassius auratus L., 1758, (Pisces: Cyprinidae) using the micronucleus test and the comet assay in peripheral blood erythrocytes. Fish were exposed to 5, 10 and 15 μg/L atrazine and to its commercial formulation for 2, 4 and 6 days. Ethyl methane sulfonate (EMS) at a single dose of 5 mg/L was used as positive control. Our results revealed significant increases in the frequencies of micronuclei and DNA strand breaks in erythrocytes of C. auratus, following exposure to commercial formulation of atrazine and thus demonstrated the genotoxic potential of this pesticide on fish.

  3. Desain dan Implementasi Sistem Kendali CNC Router Menggunakan PC untuk Flame Cutting Machine

    OpenAIRE

    Roni Permana Saputra; Anwar Muqorobin; Arif Santoso; Teguh Pudji Purwanto

    2012-01-01

    This paper focuses on design of router control systems based on computer numerical control (CNC) using personal computer (PC) implemented in flame cutting machine (FCM). NC-Code entered into the computer translated to be a command signal sent by the PC to a microcontroller to control the end effector’s movement alongthe X and Y axis simultaneously based on linear and circular interpolations calculation on the PC. This control system is implemented on FCM by connecting the output control of th...

  4. ELIPGRID-PC: A PC program for calculating hot spot probabilities

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, J.R.

    1994-10-01

    ELIPGRID-PC, a new personal computer program has been developed to provide easy access to Singer`s 1972 ELIPGRID algorithm for hot-spot detection probabilities. Three features of the program are the ability to determine: (1) the grid size required for specified conditions, (2) the smallest hot spot that can be sampled with a given probability, and (3) the approximate grid size resulting from specified conditions and sampling cost. ELIPGRID-PC also provides probability of hit versus cost data for graphing with spread-sheets or graphics software. The program has been successfully tested using Singer`s published ELIPGRID results. An apparent error in the original ELIPGRID code has been uncovered and an appropriate modification incorporated into the new program.

  5. Thin-Layer Chromatography: Comparative Estimation of Soil’s Atrazine

    Directory of Open Access Journals (Sweden)

    Vijay Kumar

    2013-12-01

    Full Text Available Herbicide atrazine is a broad spectrum herbicide, used worldwide to protect the crops from weeds, but overuse of atrazine have caused the huge environmental problems from few decades. So it is very essential to study and develop the lab based analytical methods, which are important for the detection of atrazine in environment as well as in biological media. In this study we have collected the soils samples from farm fields and extracted the atrazine by Soxhlet method. Also we have extracted the atrazine from formulated grade considered as standard/pure sample in our study. Both extracted/standard and atrazine samples were characterized by UV and FTIR analysis. Further thin layer chromatography was run to check the purity of soil extracted sample.

  6. USL/DBMS NASA/PC R and D project C programming standards

    Science.gov (United States)

    Dominick, Wayne D. (Editor); Moreau, Dennis R.

    1984-01-01

    A set of programming standards intended to promote reliability, readability, and portability of C programs written for PC research and development projects is established. These standards must be adhered to except where reasons for deviation are clearly identified and approved by the PC team. Any approved deviation from these standards must also be clearly documented in the pertinent source code.

  7. Simulation of atrazine and metabolite transport and fate in a sandy-till aquifer

    Science.gov (United States)

    Levy, Jonathan; Chesters, Gordon

    1995-11-01

    In a 2.5-yr field study we determined the distribution of atrazine and its metabolites in a sandy-till aquifer overlying Cambrian sandstone in a dairy farming area. Flow paths are predominantly downward at piezometer nests where vertical hydraulic gradients dominate. Atrazine and desethylated atrazine concentrations along those flow paths generally decrease with increasing estimated groundwater travel time to the monitoring points. A one-dimensional contaminant transport model is developed in FORTRAN incorporating major chemical processes and dispersion along simulated flow paths. Separate simulations of atrazine and desethylated atrazine transport to individual piezometers are made, each with an appropriate average groundwater velocity. Regression equations are developed, based on an extensive literature review, to estimate acceptable sorption and dispersivity coefficients for the transport model. The one-dimensional simulations are calibrated using the field concentration-travel time relationships for atrazine and desethylated atrazine. The calibration procedure provides estimates of atrazine and desethylated atrazine degradation rates in groundwater corresponding to half-lives of 3470 and 2770 days, respectively. Although uncertain, the estimates provide evidence of much slower degradation in the aquifer than indicated by laboratory experiments. Using the calibrated transport parameter values, simulations of long-term steady-state leaching to the water table demonstrate that even with such slow degradation rates, steady-state concentrations at most piezometers are reached within ˜ 20 yr. Concentrations in the underlying sandstone aquifer are therefore not expected to increase substantially over time due to continued atrazine use. However, the slow degradation rates mean that even with the most optimistic condition, i.e. all input to the aquifer ceases in response to a cessation of atrazine application, it may take more than a decade for concentrations deeper in

  8. [Degradation dynamics of POPs atrazine in soils under long-term located fertilization conditions].

    Science.gov (United States)

    Wang, Jun; Zhu, Lu-sheng; Xie, Hui; Song, Yan; Sun, Rui-lian; Zhang, Fu-dao

    2007-12-01

    To evaluate the difference of POPs atrazine degradation dynamics in soils under different fertilization conditions, we set up an analysis method of the atrazine residue in soils and studied residue dynamics of atrazine in soils under a long-term located fertilization conditions. After extracted by surging with acetone, liquid-liquid partition and eluted through florisil, the residue of atrazine in soils was detected by gas chromatogram with 63Ni-ECD. The minimum detectable quantity of atrazine is 6.4 x 10(-12) g and the minimum detectable concentration is 6.4 x 10(-9) g x kg(-1) in the soil. The spiked recoveries of atrazine with the three concentration of 0.11, 1.1, 11.0 mg x kg(-1) in soils are 91.41% +/- 4.36%, 93.58% +/- 4.54%, 90.35% +/- 3.59%, according with the request of pesticide residue analysis. The degradation of atrazine in soil under a long-term located fertilization conditions was studied. The results show the degradation of atrazine follows stair dynamic equation, and the degradation half-life of atrazine in soils fertilized with CK, NPK, NPK + M, NPK + S are 20.6, 23.0, 28.5, 33.2 d, respectively. Subjected to analysis of LSR, NPK and organic fertilizers are obviously propitious to the degradation of atrazine. The separate regression and stepwise regression analysis prove the degradation half-life of atrazine in soils is well related with the content of alkaline nitrogen, organic matter and total nitrogen, and the coefficients are 0.9983, 0.9826 and 0.9521, respectively. Maybe the reason is that these soil nutrient substance offers enough the element carbon and nitrogen for action of microbe, and the higher action of microbe quickens the degradation of atrazine in soils.

  9. Evaluation of the side effects of poly(epsilon-caprolactone nanocapsules containing atrazine towards maize plants

    Directory of Open Access Journals (Sweden)

    Halley Caixeta Oliveira

    2015-10-01

    Full Text Available Poly(epsilon-caprolactone (PCL nanocapsules have been used as a carrier system for the herbicide atrazine, which is commonly applied to maize. We demonstrated previously that these atrazine containing polymeric nanocapsules were ten-fold more effective in the control of mustard plants (a target species, as compared to a commercial atrazine formulation. Since atrazine can have adverse effects on non-target crops, here we analyzed the effect of encapsulated atrazine on growth, physiological and oxidative stress parameters of soil-grown maize plants (Zea mays L.. One day after the post-emergence treatment with PCL nanocapsules containing atrazine (1 mg mL-1, maize plants presented 15 and 21 % decreases in maximum quantum yield of photosystem II and in net CO2 assimilation rate, respectively, as compared to water-sprayed plants. The same treatment led to a 1.8-fold increase in leaf lipid peroxidation in comparison with control plants. However, all of these parameters were unaffected four and eight days after the application of encapsulated atrazine. These results suggested that the negative effects of atrazine were transient, probably due to the ability of maize plants to detoxify the herbicide. When encapsulated atrazine was applied at a ten-fold lower concentration (0.1 mg mL-1, a dosage that is still effective for weed control, no effects were detected even shortly after application. Regardless of the herbicide concentration, neither pre- nor post-emergence treatment with the PCL nanocapsules carrying atrazine resulted in the development of any macroscopic symptoms in maize leaves, and there were no impacts on shoot growth. Additionally, no effects were observed when plants were sprayed with PCL nanocapsules without atrazine. Overall, these results suggested that the use of PCL nanocapsules containing atrazine did not lead to persistent side effects in maize plants, and that the technique could offer a safe tool for weed control without affecting

  10. Combined soil washing and CDEO for the removal of atrazine from soils

    OpenAIRE

    Vieira Santos, Elisama; Saez, C.; Martínez-Huitle, Carlos A.; Cañizares Cañizares, Pablo; Rodrigo Rodrigo, Manuel Andrés

    2015-01-01

    In this work, it is studied the removal of atrazine from spiked soils by soil washing using surfactant fluids, followed by the treatment of the resulting washing waste by electrolysis with boron doped diamond anode. Results confirm that combination of both technologies is efficient for the removal and total mineralization of atrazine. Ratio surfactant/soil is a key parameter for the removal of atrazine from soil and influences significantly in the characteristic of the wastewater produced, af...

  11. Rapid development of enhanced atrazine degradation in a Dundee silt loam soil under continuous corn and in rotation with cotton.

    Science.gov (United States)

    Zablotowicz, Robert M; Krutz, L Jason; Reddy, Krishna N; Weaver, Mark A; Koger, Clifford H; Locke, Martin A

    2007-02-07

    Mississippi Delta cotton (Gossypium hirsutum L.) production in rotation with corn (Zea mays L.) was evaluated in field experiments from 2000 to 2005 at Stoneville, Mississippi. Plots maintained under minimum tillage were established in 2000 on a Dundee silt loam with treatments including continuous cotton or corn and alternate cotton-corn rotations. Mineralization and dissipation of 14C [ring]-labeled atrazine were evaluated in the laboratory on soils collected prior to herbicide application in the first, second, third, and sixth years of the study. In soils collected in 2000, a maximum of 10% of the atrazine was mineralized after 30 days. After 1 year of herbicide application, atrazine-treated soils mineralized 52-57% of the radiolabeled atrazine in 30 days. By the sixth year of the study, greater than 59% of the atrazine was mineralized after 7 days in soils treated with atrazine, while soils from plots with no atrazine treatment mineralized less than 36%. The data also indicated rapid development of enhanced atrazine degradation in soils following 1 year of corn production with atrazine use. Atrazine mineralization was as rapid in soils under a rotation receiving biannual atrazine applications as in soils under continuous corn receiving annual applications of atrazine. Cumulative mineralization kinetics parameters derived from the Gompertz model (k and ti) were highly correlated with a history of atrazine application and total soil carbon content. Changes in the soil microbial community assessed by total fatty acid methyl ester (FAME) analysis indicated significant interactions of cropping system and sampling date, with FAME indicators for soil bacteria responsible for differences in community structure. Autoclaved soil lost all ability to mineralize atrazine, and atrazine-mineralizing bacteria were isolated from these plots, confirming the biological basis for atrazine mineralization. These results indicate that changes in degradative potential of a soil can

  12. [Effects of nitrogen and phosphorus fertilizer on atrazine degradation and detoxification by degrading strain HB-5].

    Science.gov (United States)

    Su, Jun; Zhu, Lu-Sheng; Li, Xu-Hua; Wang, Jun; Xie, Hui; Wang, Jin-Hua; Wang, Qi; Jia, Wen-Tao

    2010-10-01

    An atrazine-degrading strain HB-5 was used as a bacteria for biodegradation. Treatments of soil with nitrogen single, phosphate single and nitrogen phosphate together with HB-5 were carried out for degradation and eco-toxicity test; then, relationship between atrazine degradation rate and soil available nitrogen, available phosphorus were discussed. Atrazine residues were determined by HPLC; available nitrogen was determined with alkaline hydrolysis diffusion method; available phosphorus was determined with 0.5 mol/L-NaHCO3 extraction and molybdenum stibium anti-color method, and toxicity test was carried out with micronucleus test of Vicia faba root tip cells. The results showed that: After separately or together application, nitrogenous and phosphorous fertilizers could significantly accelerate atrazine degradation than soil with HB-5 only. On day 5, the order of atrazine degradation was ANP > AP > AN > A; 7 days later, no statistically significant differences were found between treatments. The available nitrogen and phosphorus level in soil reduced as the degradation rate increased in the soil. The soil of eco-toxicity test results indicated that the eco-toxicity significantly reduced with the degradation of atrazine by HB-5, and the eco-toxicity on treatments of soil with fertilizer were all below the treatments without fertilizer. On day 5, the order of eco-toxicity was ANP atrazine degradation in soil but also could reduce the soil eco-toxicity effects that atrazine caused. All these results could be keystone of atrazine pollution remediation in contaminated soil in the future.

  13. Accelerated degradation of (14)C-atrazine in brazilian soils from different regions.

    Science.gov (United States)

    Martinazzo, Rosane; Jablonowski, Nicolai D; Hamacher, Georg; Dick, Deborah P; Burauel, Peter

    2010-07-14

    The repeated use of a given pesticide may induce a selection of the soil microbial population, resulting in a rapid degradation of the respective xenobiotic. Patterns of atrazine degradation (mineralization, formation of metabolites and nonextractable residues (NER)) were evaluated in two Brazilian soils with a history of atrazine application. Results were compared with those obtained from soils that had no agricultural use or herbicide application history. (14)C-Atrazine mineralization in unsaturated treated soils was high. By the 85th day of incubation, 82% of the applied (14)C-atrazine was mineralized in the Rhodic Hapludox and 74% in the Xanthic Haplustox. Mineralization remained low in nontreated soils (atrazine mineralization in the treated Xantic Haplustox and surprisingly also in the nontreated Rhodic Hapludox (98 and 83% on the 85th day, respectively), whereas in the other samples the evolved (14)CO(2) did not differ (p atrazine directly after (14)C-atrazine application was higher in both Xanthic Haplustox samples (around 80% of applied atrazine) in comparison to the Rhodic Hapludox samples (around 60%). Extractable activity and the formation of metabolites and NER varied among the studied soils according to the atrazine application history rather than the soil characteristics.

  14. Atrazine and glyphosate dynamics in a lotic ecosystem: the common snapping turtle as a sentinel species.

    Science.gov (United States)

    Douros, Derrick L; Gaines, Karen F; Novak, James M

    2015-03-01

    Atrazine and glyphosate are two of the most common pesticides used in the US Midwest that impact water quality via runoff, and the common snapping turtle (Chelydra serpentina) is an excellent indicator species to monitor these pesticides especially in lotic systems. The goals of this study were to (1) quantify atrazine, the atrazine metabolite diaminochlorotriazine (DACT), and glyphosate burdens in common snapping turtle tissue from individuals collected within the Embarras River in Illinois; (2) quantify atrazine, DACT, and glyphosate loads in water from the aquatic habitats in which common snapping turtles reside; and (3) investigate tissue loads based on turtle morphology and habitat choice. Concentrations of atrazine, DACT, and glyphosate in tissue did not show any relationship with lake habitat, carapace length, width, or mass. Both atrazine and glyphosate tissue samples varied as a function of site (river vs. lake), but DACT did not. Atrazine and glyphosate concentrations in water samples showed a linear effect on distance from the reservoir spillway and a deviation from linearity. Water column concentrations of all three contaminants varied across capture sites, but atrazine water concentration did not influence DACT water concentration nor did it exhibit a site interaction. Water atrazine and glyphosate concentrations were greater than tissue concentrations, whereas DACT water and tissue concentrations did not differ. This study showed that turtles are useful in long-term pesticide monitoring, and because DACT as a metabolite is less sensitive to variation, it should be considered as a preferred biomarker for pesticide runoff.

  15. Isolation and characterization of atrazine mineralizing Bacillus subtilis strain HB-6.

    Directory of Open Access Journals (Sweden)

    Jinhua Wang

    Full Text Available Atrazine is a widely used herbicide with great environmental concern due to its high potential to contaminate soil and waters. An atrazine-degrading bacterial strain HB-6 was isolated from industrial wastewater and the 16S rRNA gene sequencing identified HB-6 as a Bacillus subtilis. PCR assays indicated that HB-6 contained atrazine-degrading genes trzN, atzB and atzC. The strain HB-6 was capable of utilizing atrazine and cyanuric acid as a sole nitrogen source for growth and even cleaved the s-triazine ring and mineralized atrazine. The strain demonstrated a very high efficiency of atrazine biodegradation with a broad optimum pH and temperature ranges and could be enhanced by cooperating with other bacteria, suggesting its huge potential for remediation of atrazine-contaminated sites. To our knowledge, there are few Bacillus subtilis strains reported that can mineralize atrazine, therefore, the present work might provide some new insights on atrazine remediation.

  16. In vitro selection of a single-stranded DNA molecular recognition element against atrazine.

    Science.gov (United States)

    Williams, Ryan M; Crihfield, Cassandra L; Gattu, Srikanth; Holland, Lisa A; Sooter, Letha J

    2014-08-18

    Widespread use of the chlorotriazine herbicide, atrazine, has led to serious environmental and human health consequences. Current methods of detecting atrazine contamination are neither rapid nor cost-effective. In this work, atrazine-specific single-stranded DNA (ssDNA) molecular recognition elements (MRE) were isolated. We utilized a stringent Systematic Evolution of Ligands by Exponential Enrichment (SELEX) methodology that placed the greatest emphasis on what the MRE should not bind to. After twelve rounds of SELEX, an atrazine-specific MRE with high affinity was obtained. The equilibrium dissociation constant (Kd) of the ssDNA sequence is 0.62 ± 0.21 nM. It also has significant selectivity for atrazine over atrazine metabolites and other pesticides found in environmentally similar locations and concentrations. Furthermore, we have detected environmentally relevant atrazine concentrations in river water using this MRE. The strong affinity and selectivity of the selected atrazine-specific ssDNA validated the stringent SELEX methodology and identified a MRE that will be useful for rapid atrazine detection in environmental samples.

  17. Isolation and characterization of atrazine mineralizing Bacillus subtilis strain HB-6.

    Science.gov (United States)

    Wang, Jinhua; Zhu, Lusheng; Wang, Qi; Wang, Jun; Xie, Hui

    2014-01-01

    Atrazine is a widely used herbicide with great environmental concern due to its high potential to contaminate soil and waters. An atrazine-degrading bacterial strain HB-6 was isolated from industrial wastewater and the 16S rRNA gene sequencing identified HB-6 as a Bacillus subtilis. PCR assays indicated that HB-6 contained atrazine-degrading genes trzN, atzB and atzC. The strain HB-6 was capable of utilizing atrazine and cyanuric acid as a sole nitrogen source for growth and even cleaved the s-triazine ring and mineralized atrazine. The strain demonstrated a very high efficiency of atrazine biodegradation with a broad optimum pH and temperature ranges and could be enhanced by cooperating with other bacteria, suggesting its huge potential for remediation of atrazine-contaminated sites. To our knowledge, there are few Bacillus subtilis strains reported that can mineralize atrazine, therefore, the present work might provide some new insights on atrazine remediation.

  18. Atrazine and its degradates have little effect on the corticosteroid stress response in the zebrafish.

    Science.gov (United States)

    Van Der Kraak, Glen; Matsumoto, Jacquie; Kim, Myoungwoo; Hosmer, Alan J

    2015-04-01

    The present study examined the effects of atrazine on basal and forced swimming induced changes in whole body cortisol content in adult zebrafish. Zebrafish were exposed to graded concentrations of atrazine or the atrazine degradates deisopropylatrazine (DIA), deethylatrazine (DEA) and diamino-s-chlorotriazine (DACT) for up to 10 days. Some fish were sampled for the measurement of whole body cortisol levels under basal conditions while others were sampled after being subjected to a 20 min swimming challenge in order to quantify stress induced cortisol levels. In one experiment, zebrafish were subjected to two bouts of forced swimming 3h apart to test whether prior atrazine exposure affects the ability of the fish to respond appropriately to a repeated stressor. The results demonstrated that controls not exposed to atrazine and zebrafish exposed to atrazine or the atrazine degradates at nominal concentrations of up to 100 μg/L consistently exhibited increased whole body cortisol content in response to the swimming challenge. Separate analyses revealed few changes in basal or stress induced cortisol levels following atrazine exposure. Overall, these data suggest that atrazine and some of its degradates at the concentrations tested have minimal effects on the cortisol mediated stress response in the zebrafish.

  19. Phytoremediation potential of the novel atrazine tolerant Lolium multiflorum and studies on the mechanisms involved

    Energy Technology Data Exchange (ETDEWEB)

    Merini, Luciano J. [Catedra de Microbiologia Industrial y Biotecnologia, Universidad de Buenos Aires (Argentina); Bobillo, Cecilia [Servicio de Huellas Digitales Geneticas, Facultad de Farmacia y Bioquimica, Microbiologia Industrial y Biotecnologia, Universidad de Buenos Aires, Junin 956, BS As (Argentina); Cuadrado, Virginia [Catedra de Microbiologia Industrial y Biotecnologia, Universidad de Buenos Aires (Argentina); Corach, Daniel [Servicio de Huellas Digitales Geneticas, Facultad de Farmacia y Bioquimica, Microbiologia Industrial y Biotecnologia, Universidad de Buenos Aires, Junin 956, BS As (Argentina); Giulietti, Ana M., E-mail: agiule@ffyb.uba.a [Catedra de Microbiologia Industrial y Biotecnologia, Universidad de Buenos Aires (Argentina)

    2009-11-15

    Atrazine impact on human health and the environment have been extensively studied. Phytoremediation emerged as a low cost, environmental friendly biotechnological solution for atrazine pollution in soil and water. In vitro atrazine tolerance assays were performed and Lolium multiflorum was found as a novel tolerant species, able to germinate and grow in the presence of 1 mg kg{sup -1} of the herbicide. L. multiflorum presented 20% higher atrazine removal capacity than the natural attenuation, with high initial degradation rate in microcosms. The mechanisms involved in atrazine tolerance such as mutation in psbA gene, enzymatic detoxification via P{sub 450} or chemical hydrolysis through benzoxazinones were evaluated. It was demonstrated that atrazine tolerance is conferred by enhanced enzymatic detoxification via P{sub 450}. Due to its atrazine degradation capacity in soil and its agronomical properties, L. multiflorum is a candidate for designing phytoremediation strategies for atrazine contaminated agricultural soils, especially those involving run-off avoiding. - Finding of a novel atrazine-tolerant species, as a potential candidate for phytoremediating herbicide-contaminated agriculture soils and elucidation of the mechanisms involved in tolerance.

  20. Mineralization and degradation of glyphosate and atrazine applied in combination in a Brazilian Oxisol.

    Science.gov (United States)

    Bonfleur, Eloana J; Lavorenti, Arquimedes; Tornisielo, Valdemar L

    2011-01-01

    The aim of this study was to investigate the behavior of the association between atrazine and glyphosate in the soil through mineralization and degradation tests. Soil treatments consisted of the combination of a field dose of glyphosate (2.88 kg ha⁻¹) with 0, ½, 1 and 2 times a field dose of atrazine (3.00 kg ha⁻¹) and a field dose of atrazine with 0, ½, 1 and 2 times a field dose of glyphosate. The herbicide mineralization rates were measured after 0, 3, 7, 14, 21, 28, 35, 42, 49, 56 and 63 days of soil application, and degradation rates after 0, 7, 28 and 63 days. Although glyphosate mineralization rate was higher in the presence of 1 (one) dose of atrazine when compared with glyphosate alone, no significant differences were found when half or twice the atrazine dose was applied, meaning that differences in glyphosate mineralization rates cannot be attributed to the presence of atrazine. On the other hand, the influence of glyphosate on atrazine mineralization was evident, since increasing doses of glyphosate increased the atrazine mineralization rate and the lowest dose of glyphosate accelerated atrazine degradation.

  1. FATE OF ATRAZINE IN THE AGRICULTURAL SOIL OF CORN FIELDS IN FARS PROVINCE OF IRAN

    Directory of Open Access Journals (Sweden)

    S. Nasseri ، M. Dehghani ، S. Amin ، K. Naddafi ، Z. Zamanian

    2009-10-01

    Full Text Available Atrazine, a herbicide widely used in corn production, is frequently detected as pesticide in water resources. In this research, four agricultural fields with a long history of atrazine application in Shiraz and its vicinity in Fars province of Iran, have been studied to determine the fate of atrazine through the passage of time. These four farms were cultivated under a crop rotation (corn-wheat during the past 10 years. Samples were collected from four soil profiles of 0-10, 10-20, 20-40, and 40-60 cm soil depth at different times. The time intervals for soil sampling started before atrazine application and continued until no atrazine was detected. According to the general linear model, there was no significant difference between atrazine residual concentrations and the soil moisture and depth (p≥0.05. But, significant difference between atrazine residual concentrations and the sampling regions was observed (p<0.001. Based on the data, atrazine leaching and dissipation rate in different soil profiles in the four sampling regions were high and significant. Therefore, there is a high risk of atrazine pollution in groundwater resources of the region.

  2. Nanoencapsulation Enhances the Post-Emergence Herbicidal Activity of Atrazine against Mustard Plants.

    Directory of Open Access Journals (Sweden)

    Halley Caixeta Oliveira

    Full Text Available Poly(epsilon-caprolactone (PCL nanocapsules have been recently developed as a modified release system for atrazine, an herbicide that can have harmful effects in the environment. Here, the post-emergence herbicidal activity of PCL nanocapsules containing atrazine was evaluated using mustard (Brassica juncea as target plant species model. Characterization of atrazine-loaded PCL nanocapsules by nanoparticle tracking analysis indicated a concentration of 7.5 x 10(12 particles mL(-1 and an average size distribution of 240.7 nm. The treatment of mustard plants with nanocapsules carrying atrazine at 1 mg mL(-1 resulted in a decrease of net photosynthesis and PSII maximum quantum yield, and an increase of leaf lipid peroxidation, leading to shoot growth inhibition and the development of severe symptoms. Time course analysis until 72 h after treatments showed that nanoencapsulation of atrazine enhanced the herbicidal activity in comparison with a commercial atrazine formulation. In contrast to the commercial formulation, ten-fold dilution of the atrazine-containing nanocapsules did not compromise the herbicidal activity. No effects were observed when plants were treated with nanocapsules without herbicide compared to control leaves sprayed with water. Overall, these results demonstrated that atrazine-containing PCL nanocapsules provide very effective post-emergence herbicidal activity. More importantly, the use of nanoencapsulated atrazine enables the application of lower dosages of the herbicide, without any loss of efficiency, which could provide environmental benefits.

  3. In Vitro Selection of a Single-Stranded DNA Molecular Recognition Element against Atrazine

    Directory of Open Access Journals (Sweden)

    Ryan M. Williams

    2014-08-01

    Full Text Available Widespread use of the chlorotriazine herbicide, atrazine, has led to serious environmental and human health consequences. Current methods of detecting atrazine contamination are neither rapid nor cost-effective. In this work, atrazine-specific single-stranded DNA (ssDNA molecular recognition elements (MRE were isolated. We utilized a stringent Systematic Evolution of Ligands by Exponential Enrichment (SELEX methodology that placed the greatest emphasis on what the MRE should not bind to. After twelve rounds of SELEX, an atrazine-specific MRE with high affinity was obtained. The equilibrium dissociation constant (Kd of the ssDNA sequence is 0.62 ± 0.21 nM. It also has significant selectivity for atrazine over atrazine metabolites and other pesticides found in environmentally similar locations and concentrations. Furthermore, we have detected environmentally relevant atrazine concentrations in river water using this MRE. The strong affinity and selectivity of the selected atrazine-specific ssDNA validated the stringent SELEX methodology and identified a MRE that will be useful for rapid atrazine detection in environmental samples.

  4. Determination of atrazine and its biodegradation intermediates in bacterial enrichments obtained from Uruguayan water courses

    Directory of Open Access Journals (Sweden)

    Jonathan Da Cunha

    2013-12-01

    Full Text Available Atrazine is an herbicide used to control annual weeds and perennial grasses. Due to the toxicity of atrazine and its metabolites, this herbicide is banned in the European Union. In Uruguay atrazine is the second most frequently imported herbicide. It has been detected in surface water courses, particularly those that provide water for potabilization plants.The main mechanism for atrazine removal in neutral pH environments is the bacterial degradation. The microorganisms can degrade atrazine giving intermediates that vary in persistence and toxicity, or mineralize it giving ammonia and carbondioxide. The separation and detection of atrazine intermediates of biological degradation is important to know the potential of bacterial consortia to be applied in bioremediation processes. In this paper we developed an isocratic method of high performance liquid chromatography (HPLC by ion-pair reversed phase to separate atrazine and metabolites in a synthetic culture medium. This method was useful to detect intermediates of atrazine degradation produced by selected native bacterial consortia. In addition, the method was employed to assess if atrazine adsorbed on activated carbon could be degraded by an active degrading consortium.

  5. Degradation of atrazine in soil through induced photocatalytic processes

    Energy Technology Data Exchange (ETDEWEB)

    Pelizzetti, E. (Univ. di Parma (Italy)); Carlin, V.; Maurino, V.; Minero, C.; Dolci, M. (Univ. di Torino (Italy)); Marchesini, A. (Istituto Sperimentale per la Nutrizione delle Piante, Torino (Italy))

    1990-08-01

    The authors observed photocatalytic degradation of atrazine in the presence of semiconductor metal oxide particulates (TiO{sub 2}, ZnO) suspended in aqueous solution under simulated sunlight irradiation. The half-life for the process is ca. 5 and 80 min for TiO{sub 2} and ZnO, respectively (at an initial atrazine concentration of 25 mg/liter with 0.5 g of semiconductor per liter and with a photon flux of 3 {times} 10{sup {minus}5} einstein/min, and over a cell cross section of 4 cm{sup 2}). The authors investigated the catalytic activity of different soils. The weak photocatalytic activity of the soils (2 g/liter) is dramatically increased by the addition of 0.5 g of the semiconductor per liter. Half-lives are 10 to 40 minutes, depending on the nature of the soil.

  6. Photocatalytic degradation of atrazine by porphyrin and phthalocyanine complexes.

    Science.gov (United States)

    Héquet, V; Le Cloirec, P; Gonzalez, C; Meunier, B

    2000-08-01

    This study principally focused on a new kind of photochemical reaction catalyst: porphyrin and phthalocyanine complexes. In a first step, the preparation of the catalysts was optimized. A resin has been chosen to be the support of the complexes. Efficiency of catalytic activity is performed on the degradation of a pesticide: atrazine. The best atrazine degradation occurs with 4.6% of complexes versus substrate. The role of the surface has also been shown to be important. Then, their performances were demonstrated in terms of kinetics and degradation routes, compared to a classical catalyst: titanium dioxide. This study seeks to assess the efficiency of these systems both in a mercury lamp reactor and under solar irradiation which reduces energy costs. The best atrazine degradation half-life found for the complexes is about 200 min with the iron phthalocyanine. These catalysts exhibit particular oxidation activities. Indeed, the degradation routes have been found different between the semi-conductor and the metallic complexes. These complexes are able to cleave the triazinic ring more efficiently than the titanium dioxide.

  7. Residues of atrazine in agricultural areas of Serbia

    Directory of Open Access Journals (Sweden)

    N. NESKOVIC

    2002-12-01

    Full Text Available In this paper the results of a five-year investigation of the pollution of soil, as well as of surface and groundwater by atrazine are reported. The soil samples were collected from different localities, from the tillage level, at two depths (0–15 and 15–30 cm during the period September-November from 1995 to 1999. The surface and groundwater samples were taken from the same localities during the same period. The residues were detected by the ELISA test. The results showed that almost all the analysed soil samples contained residues of atrazine. These quantities varied from 0.02 to 0.10 mg/kg (0–15 cm, and up to 0.05 mg/kg (15–30 cm, depending on the locality, soil type and the year of investigation. Concerning the residues in the surface and groundwater, it was found that most of the analysed samples contained atrazine residues. In the case of the surface water, the quantity of the residues ranged from 1.0 to 4.13 mg/L, whill the ground water contained up to 0.3 mg/L depending on the locality and the year of investigation.

  8. Nucleophilic substitution as a mechanism of atrazine sequestration in soil

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Junhe, E-mail: jhlu@njau.edu.cn [Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing 210095 (China); Shao, Juan [Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing 210095 (China); Kong, Deyang [Nanjing Institute of Environmental Science, Ministry of Environmental Protection of PRC, Nanjing 210042 (China)

    2015-03-02

    Highlights: • Atrazine tends to form nonextractable bound residue in soil. • Nucleophilic substitution is a pathway leading to atrazine sequestration in soil. • Sulfur containing amino acids are likely to play an important role as nucleophiles during this process. - Abstract: Formation of nonextractable residue was widely observed as a sink of atrazine (ATZ) in soil. However, the mechanisms by which ATZ binds to soil organic matter remain unclear. In this study, we demonstrated that neucleophilic substitution could serve an important pathway causing ATZ sequestration. The carbon bonded to the chlorine in ATZ molecule is partially positively charged due to the strong electronegativity of chlorine and is susceptible to the attack of nucleophiles such as aniline. Since aromatic amines are relatively rare in natural soils, amino acids/peptides were hypothesized to act as the main nucleophiles in real environment. However, substantially ATZ transformation was only observed in the presence of those species containing thiol functionality. Thus, we speculated that it was the thiol group in amino acids/peptides acting as the nucleophile. Nitrogen in amino acids was in fact not an active nucleophile toward ATZ. In addition to the sulfur-containing amino acids, other thiol compounds, and sulfide were also proved to be reactive to ATZ. Thus, the sequestration potential of ATZ probably correlates to the availability of thiol compounds in soil.

  9. Monitoring bioremediation of atrazine in soil microcosms using molecular tools.

    Science.gov (United States)

    Sagarkar, Sneha; Mukherjee, Shinjini; Nousiainen, Aura; Björklöf, Katarina; Purohit, Hemant J; Jørgensen, Kirsten S; Kapley, Atya

    2013-01-01

    Molecular tools in microbial community analysis give access to information on catabolic potential and diversity of microbes. Applied in bioremediation, they could provide a new dimension to improve pollution control. This concept has been demonstrated in the study using atrazine as model pollutant. Bioremediation of the herbicide, atrazine, was analyzed in microcosm studies by bioaugmentation, biostimulation and natural attenuation. Genes from the atrazine degrading pathway atzA/B/C/D/E/F, trzN, and trzD were monitored during the course of treatment and results demonstrated variation in atzC, trzD and trzN genes with time. Change in copy number of trzN gene under different treatment processes was demonstrated by real-time PCR. The amplified trzN gene was cloned and sequence data showed homology to genes reported in Arthrobacter and Nocardioides. Results demonstrate that specific target genes can be monitored, quantified and correlated to degradation analysis which would help in predicting the outcome of any bioremediation strategy.

  10. Influence of microbial and synthetic surfactant on the biodegradation of atrazine.

    Science.gov (United States)

    Singh, Anil Kumar; Cameotra, Swaranjit Singh

    2014-02-01

    The present study reports the effect of surfactants (rhamnolipids and triton X-100) on biodegradation of atrazine herbicide by strain A6, belonging to the genus Acinetobacter. The strain A6 was able to degrade nearly 80 % of the 250-ppm atrazine after 6 days of growth. The bacterium degraded atrazine by de-alkylation process. Bacterial cell surface hydrophobicity as well as atrazine solubility increased in the presence of surfactant. However, addition of surfactant to the mineral salt media reduced the rate and extent of atrazine degradation by decreasing the bioavailability of herbicide. On the contrary, addition of surfactant to atrazine-contaminated soil increased the rate and extent of biodegradation by increasing the bioavailability of herbicide. As compared to triton X-100, rhamnolipids were more efficient in enhancing microbial degradation of atrazine as a significant amount of atrazine was removed from the soil by rhamnolipids. Surfactants added for the purpose of hastening microbial degradation may have an unintended inhibitory effect on herbicide degradation depending upon contiguous condition, thus highlighting the fact that surfactant must be judiciously used in bioremediation of herbicides.

  11. Atrazine and its metabolites degradation in mineral salts medium and soil using an enrichment culture.

    Science.gov (United States)

    Kumar, Anup; Singh, Neera

    2016-03-01

    An atrazine-degrading enrichment culture was used to study degradation of atrazine metabolites viz. hydroxyatrazine, deethylatrazine, and deisopropylatrazine in mineral salts medium. Results suggested that the enrichment culture was able to degrade only hydroxyatrazine, and it was used as the sole source of carbon and nitrogen. Hydroxyatrazine degradation slowed down when sucrose and/or ammonium hydrogen phosphate were supplemented as the additional sources of carbon and nitrogen, respectively. The enrichment culture could degrade high concentrations of atrazine (up to 110 μg/mL) in mineral salts medium, and neutral pH was optimum for atrazine degradation. Further, except in an acidic soil, enrichment culture was able to degrade atrazine in three soil types having different physico-chemical properties. Raising the pH of acidic soil to neutral or alkaline enabled the enrichment culture to degrade atrazine suggesting that acidic pH inhibited atrazine-degrading ability. The study suggested that the enrichment culture can be successfully utilized to achieve complete degradation of atrazine and its persistent metabolite hydroxyatrazine in the contaminated soil and water.

  12. Catalytic effect of transition metals on microwave-induced degradation of atrazine in mineral micropores.

    Science.gov (United States)

    Hu, Erdan; Cheng, Hefa

    2014-06-15

    With their high catalytic activity for redox reactions, transition metal ions (Cu(2+) and Fe(3+)) were exchanged into the micropores of dealuminated Y zeolites to prepare effective microporous mineral sorbents for sorption and microwave-induced degradation of atrazine. Due to its ability to complex with atrazine, loading of copper greatly increased the sorption of atrazine. Atrazine sorption on iron-exchanged zeolites was also significantly enhanced, which was attributed to the hydrolysis of Fe(3+) polycations in mineral micropores and electrostatic interactions of protonated atrazine molecules with the negatively charged pore wall surface. Copper and iron species in the micropores also significantly accelerated degradation of the sorbed atrazine (and its degradation intermediates) under microwave irradiation. The catalytic effect was attributed to the easy reducibility and high oxidation activity of Cu(2+) and Fe(3+) species stabilized in the micropores of the zeolites. It was postulated that the surface species of transition metals (monomeric Cu(2+), Cu(2+)-O-Cu(2+) complexes, FeO(+), and dinuclear Fe-O-Fe-like species) in the mineral micropores were thermally activated under microwave irradiation, and subsequently formed highly reactive sites catalyzing oxidative degradation of atrazine. The transition metal-exchanged zeolites, particularly the iron-exchanged ones, were relatively stable when leached under acidic conditions, which suggests that they are reusable in sorption and microwave-induced degradation. These findings offer valuable insights on designing of effective mineral sorbents that can selectively uptake atrazine from aqueous solutions and catalyze its degradation under microwave irradiation.

  13. Assessing aquifer contamination risk using immunoassay: trace analysis of atrazine in unsaturated zone sediments

    Science.gov (United States)

    Juracek, K.E.; Thurman, E.M.

    1997-01-01

    The vulnerability of a shallow aquifer in south-central Kansas to contamination by atrazine (2-chloro-4-ethylamino-6-isopropylamines-triazine) was assessed by analyzing unsaturated zone soil and sediment samples from about 60 dryland and irrigated sites using an ultrasensitive immunoassay (detection level of 0.02 µg/kg) with verification by gas chromatography/mass spectrometry (GC/MS). Samples were collected at depths of 0 to 1.2 m (i.e., the root zone), 1.2 to 1.8 m, and 1.8 to 3.0 m during two time periods-prior to planting and after harvest of crops. About 75% of the samples contained detectable concentrations of parent atrazine. At the shallow sampling depth, atrazine concentrations ranged from 0.5 to approximately 12 µg/kg. Atrazine concentrations at the intermediate (1.2-1.8 m) depth generally were degradation of parent atrazine in the root zone. Likewise, atrazine concentrations front the deepest (1.8-3.0 m) depth ranged from atrazine use ranging from 1 to 5 or more years, there does not appear to he a significant buildup of parent compound below the root zone. Therefore, the unsaturated zone does not appear to be a major storage compartment of atrazine contamination for the underlying shallow aquifer.

  14. Effect of dairy manure rate and the stabilization time of amended soils on atrazine degradation.

    Science.gov (United States)

    Aguilera, Paula; Briceño, Gabriela; Candia, Maribel; Mora, Maria de la Luz; Demanet, Rolando; Palma, Graciela

    2009-10-01

    The application rate of liquid cow manure (LCM) in the field and the stabilization time of amended soils before application of pre-plant herbicides are factors that determine their efficiency. This study includes evaluation of residual atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) in soil and amended soils with equivalent rate of 100,000; 200,000; and 300,000 L ha(-1) of LCM and the effect of pre-incubation time of amended soils on atrazine degradation. The study was carried out under controlled conditions using an Andisol with previous historical application of atrazine. The respiratory activity and fluorescein diacetate (FDA) studies indicated that the time necessary for stabilization of amended soils is over 20-30 d. During the measurement of respiratory and FDA activity, no significant differences were observed when atrazine was applied. The half-life of atrazine ranged from 5 to 8d and the relative distribution of degradation products seem to be affected by the application of LCM. The pre-incubation time of amended soil and LCM dose would not affect atrazine degradation rate, when the soil has a history of herbicide application. However, repeated applications of LCM in a long period of time could change the soil pH and increase the content of dissolved organic carbon (DOC) which could further contribute to a faster degradation of atrazine. Both effects would reduce the effectiveness of atrazine in weed control.

  15. Enhanced atrazine removal using membrane bioreactor bioaugmented with genetically engineered microorganism

    Institute of Scientific and Technical Information of China (English)

    Chun LIU; Xia HUANG

    2008-01-01

    Bioaugmentation with genetically engineered microorganisms (GEMs) in a membrane bioreactor (MBR) for enhanced removal of recalcitrant pollutants was explored. An atrazine-degrading genetically engi-neered microorganism (GEM) with green fluorescent pro-tein was inoculated into an MBR and the effects of such a bioaugmentation strategy on atrazine removal were inves-tigated. The results show that atrazine removal was improved greatly in the bioaugmented MBR compared with a control system. After a start-up period of 6 days, average 94.7% of atrazine was removed in bioaugmented MBR when atrazine concentration of influent was 14.5 mg/L. The volu-metric removal rates increased linearly followed by atrazine loading increase and the maximum was 65.5 mg/(L·d). No negative effects were found on COD removal although carbon oxidation activity of bioaugmented sludge was lower than that of common sludge. After inoculation, adsorption to sludge flocs was favorable for GEM sur-vival. The GEM population size initially decreased shortly and then was kept constant at about 104-105 CFU/mL. Predation of micro-organisms played an important role in the decay of the GEM population. GEM leakage from MBR was less than 102 CFU/mL initially and was then undetectable. In contrast, in a conventionally activated sludge bioreactor (CAS), sludge bulking occurred possibly due to atrazine exposure, resulting in bioaugmentation failure and serious GEM leakage. So MBR was superior to CAS in atrazine bioaugmentation treatment using GEM.

  16. Atrazine retention and degradation in the vadose zone at a till plain site in central Indiana

    Science.gov (United States)

    Bayless, E.R.

    2001-01-01

    The vadose zone was examined as an environmental compartment where significant quantities of atrazine and its degradation compounds may be stored and transformed. The vadose zone was targeted because regional studies in the White River Basin indicated a large discrepancy between the mass of atrazine applied to fields and the amount of the pesticide and its degradation compounds that are measured in ground and surface water. A study site was established in a rotationally cropped field in the till plain of central Indiana. Data were gathered during the 1994 growing season to characterize the site hydrogeology and the distribution of atrazine, desethylatrazine, deisopropylatrazine, didealkylatrazine and hydroxyatrazine in runoff, pore water, and ground water. The data indicated that atrazine and its degradation compounds were transported from land surface to a depth of 1.5 m within 60 days of application, but were undetected in the saturated zone at nearby monitoring wells. A numerical model was developed, based on the field data, to provide information about processes that could retain and degrade atrazine in the vadose zone. Simulations indicated that evapotranspiration is responsible for surface directed soil-moisture flow during much of the growing season. This process causes retention and degradation of atrazine in the vadose zone. Increased residence time in the vadose zone leads to nearly complete transformation of atrazine and its degradation products to unquantified degradation compounds. As a result of mascropore flow, small quantities of atrazine and its degradation compounds may reach the saturated zone.

  17. New detection method for atrazine pesticides with the optical waveguide Mach-Zehnder immunosensor

    NARCIS (Netherlands)

    Schipper, E.F.; Bergevoet, A.J.H.; Kooyman, R.P.H.; Greve, J.

    1997-01-01

    Concentrations of analytes can be determined within a few minutes using on-line analysis of the immunobinding kinetics in a solid phase immunoassay. This approach has been applied to the detection of atrazine. Atrazine is detected, at concentrations around the European Community limit (0.1 ¿g/l) by

  18. Simulatie van de uitspoeling van het Herbicide Atrazine uit een kolom gevuld met podzolgrond

    NARCIS (Netherlands)

    Tiktak; A.*; Drecht; G.van

    1986-01-01

    Het gedrag van het herbicide Atrazine in de bodem is in het laboratorium onderzocht met behulp van grondkolommen. Over de proeven en de resultaten werd door Loch e.a. in 1985 gerapporteerd. Met behulp van model ONZAT werd de gemeten doorbraakkromme van Atrazine in een podzolgrond gesimuleerd. Da

  19. Influence of phosphate on the response of periphyton to atrazine exposure

    NARCIS (Netherlands)

    H. Guasch; V. Lehmann; B. van Beusekom; S. Sabater; W. Admiraal

    2007-01-01

    After indications from the literature that nutrient concentrations may modify the toxicity of herbicides to natural periphyton communities, this study aims to provide experimental proof for atrazine. In this microcosm experiment, phosphate (P) addition did not ameliorate atrazine toxicity to periphy

  20. Identification of an atrazine-degrading benzoxazinoid in Eastern gamagrass (tripsacum dactyloides)

    Science.gov (United States)

    This study was part of a broader effort to identify and characterize promising atrazine-degrading phytochemicals in Eastern gamagrass (Tripsacum dactyloides; EG) roots for the purpose of mitigating atrazine transport from agroecosystems. The objective of this study was to isolate and identify atrazi...

  1. Simulations of Flow Circulations and Atrazine Concentrations in a Midwest U.S. Reservoir

    Science.gov (United States)

    Zhao, Xianggui; Gu, Roy R.; Guo, Chuling; Wang, Kui; Li, Shijie

    Atrazine is the most commonly used herbicide in the spring for pre-emergent weed control in the corn cropping area in the Midwestern United States. A frequent high level of herbicide concentrations in reservoirs is a great concern for public health and aquatic ecosystems. In this study, a two-dimensional hydrodynamics and toxic contaminant transport model was applied to Saylorville Reservoir, Iowa, USA. The model simulates physical, chemical, and biological processes and predicts unsteady vertical and longitudinal distributions of a toxic chemical. Model results were validated by measured temperatures and atrazine concentrations. Simulated flow velocities, water temperatures, and chemical concentrations demonstrated that the spatial variation of atrazine concentrations was largely affected by seasonal flow circulation patterns in the reservoir. In particular, the simulated fate and transport of atrazine showed the effect of flow circulation on spatial distribution of atrazine during summer months as the river flow formed an underflow within the reservoir and resulted in greater concentrations near the surface of the reservoir. Atrazine concentrations in the reservoir peaked around the end of May and early June. A thorough understanding of the fate and transport of atrazine in the reservoir can assist in developing operation and pollution prevention strategies with respect to timing, amount, and depth of withdrawal. The responses of atrazine transport to various boundary conditions provide useful information in assessing environmental impact of alternative upstream watershed management practices on the quality of reservoir water.

  2. Model Forecasts of Atrazine in Lake Michigan in Response to Various Sensitivity and Potential Management Scenarios

    Science.gov (United States)

    For more than forty years, the herbicide atrazine has been used on corn crops in the Lake Michigan basin to control weeds. It is usually applied to farm fields in the spring before or after the corn crop emerges. A version of the WASP4 mass balance model, LM2-Atrazine, was used...

  3. Het gedrag van het herbicide ATRAZINE in kolommen met twee onverzadigde Nederlandse bodemprofielen

    NARCIS (Netherlands)

    Loch; J.P.G.; Gestel; C.A.M.van; Lagas; P.; Wegman; R.C.C.

    1985-01-01

    Het gedrag van atrazine en metabolieten in de bodem is onderzocht m.b.v. 110 cm lange grondkolommen. De kolommen bevatten profielen van een kamppodzol- en een enkeerdgrond, met een grondwaterspiegel op 1 m diepte. Atrazine werd in de bovenste 2 cm van elke kolom ingemengd. Beregening van de kol

  4. Effect of Atrazine on Antioxidant Enzyme and Its Bioaccumulation in Kidney of Crucian Carp, Carassius auratus

    Institute of Scientific and Technical Information of China (English)

    MENG Shunlong; CHEN Jiazhang; WU Wei; HU Gengdong; QU Jianhong; YOU Yang

    2011-01-01

    Etrazine is one of the most widely used herbicides in China and the world. Acute and chronic toxicity tests werc carried out to assess the possible toxicity effect of atrazine on crucian carp (Carassius auratus). Results showed that 96 h LC,. of atrazine to Carassius auratus was 105.94 mg. L-1. The enzyme activities of superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferases (GST) in kidney of Carassius auratus were all influenced by atraizine, and CAT was more sensitive to atrazine compared with SOD and GST. Atrazine residues in kidney of Carassius aura/us reached the stable state at day 19, and the bioaccumulation factors (BAF) of atrazine in kidney of Carassius auratus treated with 1.0 mg. L-1 and 10.0 mg. L-1 atrazine were 8.3 and 4.4, respectively. The research demonstrated that atrazine could cause oxidative stress to fish kidney, but atrazine was not easy to accumulate in Carassius auratus kidney, and the antioxidant enzymes could be used as biomarker to the early detection of pollution.

  5. Embryo-larval exposure to atrazine reduces viability and alters oxidative stress parameters in Drosophila melanogaster.

    Science.gov (United States)

    Figueira, Fernanda Hernandes; Aguiar, Lais Mattos de; Rosa, Carlos Eduardo da

    2017-01-01

    The herbicide atrazine has been used worldwide with subsequent residual contamination of water and food, which may cause adverse effects on non-target organisms. Animal exposure to this herbicide may affect development, reproduction and energy metabolism. Here, the effects of atrazine regarding survival and redox metabolism were assessed in the fruit fly D. melanogaster exposed during embryonic and larval development. The embryos (newly fertilized eggs) were exposed to different atrazine concentrations (10μM and 100μM) in the diet until the adult fly emerged. Pupation and emergence rates, developmental time and sex ratio were determined as well as oxidative stress parameters and gene expression of the antioxidant defence system were evaluated in newly emerged male and female flies. Atrazine exposure reduced pupation and emergence rates in fruit flies without alterations to developmental time and sex ratio. Different redox imbalance patterns were observed between males and females exposed to atrazine. Atrazine caused an increase in oxidative damage, reactive oxygen species generation and antioxidant capacity and decreased thiol-containing molecules. Further, atrazine exposure altered the mRNA expression of antioxidant genes (keap1, sod, sod2, cat, irc, gss, gclm, gclc, trxt, trxr-1 and trxr-2). Reductions in fruit fly larval and pupal viability observed here are likely consequences of the oxidative stress induced by atrazine exposure.

  6. The HR96 activator, atrazine, reduces sensitivity of D. magna to triclosan and DHA.

    Science.gov (United States)

    Sengupta, Namrata; Litoff, Elizabeth J; Baldwin, William S

    2015-06-01

    HR96 is a CAR/PXR/VDR ortholog in invertebrates, and a promiscuous endo- and xenobiotic nuclear receptor involved in acclimation to toxicants. Daphnia HR96 is activated by chemicals such as atrazine and linoleic acid (LA) (n-6 fatty acid), and inhibited by triclosan and docosahexaenoic acid (DHA) (n-3 fatty acid). We hypothesized that inhibitors of HR96 may block the protective responses of HR96 based on previously performed luciferase assays. Therefore, we performed acute toxicity tests with two-chemical mixtures containing a HR96 inhibitor (DHA or triclosan) and a HR96 activator (LA or atrazine). Surprisingly, results demonstrate that triclosan and DHA are less toxic when co-treated with 20-80 μM atrazine. Atrazine provides concentration-dependent protection as lower concentrations have no effect and higher concentrations cause toxicity. LA, a weaker HR96 activator, did not provide protection from triclosan or DHA. Atrazine's protective effects are presumably due to its ability to activate HR96 or other toxicologically relevant transcription factors and induce protective enzymes. Atrazine did not significantly induce glucosyltransferase, a crucial enzyme in triclosan detoxification. However, atrazine did increase antioxidant activities, crucial pathways in triclosan's toxicity, as measured through GST activity and the TROLOX equivalence assay. The increase in antioxidant capacity is consistent with atrazine providing protection from a wide range of toxicants that induce ROS, including triclosan and unsaturated fatty acids predisposed to lipid peroxidation.

  7. Uptake of C(14)-atrazine by prairie grasses in a phytoremediation setting.

    Science.gov (United States)

    Khrunyk, Yuliya; Schiewer, Silke; Carstens, Keri L; Hu, Dingfei; Coats, Joel R

    2017-02-01

    Agrochemicals significantly contribute to environmental pollution. In the USA, atrazine is a widely used pesticide and commonly found in rivers, water systems, and rural wells. Phytoremediation can be a cost-effective means of removing pesticides from soil. The objective of this project was to investigate the ability of prairie grasses to remove atrazine. (14)C-labeled atrazine was added to sterilized sand and water/nutrient cultures, and the analysis was performed after 21 days. Switchgrass and big bluestem were promising species for phytoremediation, taking up about 40% of the applied [(14)C] in liquid hydroponic cultures, and between 20% and 33% in sand cultures. Yellow Indiangrass showed low resistance to atrazine toxicity and low uptake of [(14)C] atrazine in liquid hydroponic cultures. Atrazine degradation increased progressively from sand to roots and leaves. Most atrazine taken up by prairie grasses from sand culture was degraded to metabolites, which accounted for 60-80% of [(14)C] detected in leaves. Deisopropylatrazine (DIA) was the main metabolite detected in sand and roots, whereas in leaves further metabolism took place, forming increased amounts of didealkylatrazine (DDA) and an unidentified metabolite. In conclusion, prairie grasses achieved high atrazine removal and degradation, showing a high potential for phytoremediation.

  8. Atrazine acts as an endocrine disrupter by inhibiting cAMP-specific phosphodiesterase-4

    Energy Technology Data Exchange (ETDEWEB)

    Kucka, Marek [Section on Cellular Signaling, Program in Developmental Neuroscience, NICHD, NIH, Bethesda, MD (United States); Pogrmic-Majkic, Kristina; Fa, Svetlana [Laboratory for Ecotoxicology, Department of Biology and Ecology, University of Novi Sad, Faculty of Sciences, 21000 Novi Sad (Serbia); Stojilkovic, Stanko S. [Section on Cellular Signaling, Program in Developmental Neuroscience, NICHD, NIH, Bethesda, MD (United States); Kovacevic, Radmila, E-mail: radmila.kovacevic@dbe.uns.ac.rs [Laboratory for Ecotoxicology, Department of Biology and Ecology, University of Novi Sad, Faculty of Sciences, 21000 Novi Sad (Serbia)

    2012-11-15

    Atrazine, one of the most commonly used herbicides worldwide, acts as an endocrine disruptor, but the mechanism of its action has not been characterized. In this study, we show that atrazine rapidly increases cAMP levels in cultured rat pituitary and testicular Leydig cells in a concentration-dependent manner, but less effectively than 3-isobutyl-1-methylxanthine, a competitive non-specific inhibitor of phosphodiesterases (PDEs). In forskolin (an activator of adenylyl cyclase)- and probenecid (an inhibitor of cyclic nucleotide transporters)-treated cells, but not in 3-isobutyl-1-methylxanthine-treated cells, atrazine further increased cAMP levels, indicating that inhibition of PDEs accounts for accumulation of cAMP. In contrast to cAMP, atrazine did not alter cGMP levels, further indicating that it inhibits cAMP-specific PDEs. Atrazine-induced changes in cAMP levels were sufficient to stimulate prolactin release in pituitary cells and androgen production in Leydig cells, indicating that it acts as an endocrine disrupter both in cells that secrete by exocytosis of prestored hormones and in cells that secrete by de novo hormone synthesis. Rolipram abolished the stimulatory effect of atrazine on cAMP release in both cell types, suggesting that it acts as an inhibitor of PDE4s, isoforms whose mRNA transcripts dominate in pituitary and Leydig cells together with mRNA for PDE8A. In contrast, immortalized lacto-somatotrophs showed low expression of these mRNA transcripts and several fold higher cAMP levels compared to normal pituitary cells, and atrazine was unable to further increase cAMP levels. These results indicate that atrazine acts as a general endocrine disrupter by inhibiting cAMP-specific PDE4s. -- Highlights: ► Atrazine stimulates cAMP accumulation in pituitary and Leydig cells. ► Atrazine also stimulates PRL and androgens secretion. ► Stimulatory effects of atrazine were abolished in cells with IBMX-inhibited PDEs. ► Atrazine specificity toward c

  9. Atrazine and terbutryn degradation in deposits from groundwater environment within the boreal region in Lahti, Finland.

    Science.gov (United States)

    Talja, K Marja; Kaukonen, Sanna; Kilpi-Koski, Johanna; Malin, Ismo; Kairesalo, Timo; Romantschuk, Martin; Tuominen, Jari; Kontro, Merja H

    2008-12-24

    The degradation of pesticides atrazine and terbutryn was investigated under aerobic and anaerobic conditions in the northern boreal region subsurface deposits and sterilized controls from the depths of 6.3-21.0 m below the surface and 1.2-16.9 m below the groundwater table. During 1.3-1.7 years of laboratory incubation, atrazine degradation under aerobic conditions varied from rapid (half-live 38 days) to no degradation. Anaerobically, atrazine half-lives were 430-829 days. Organic matter, nitrogen, and lead in deposits correlated positively with the atrazine concentration in groundwater. Aerobic and anaerobic terbutryn half-lives were 193-644 and 266-400 days, respectively. Microbial aerobic atrazine and terbutryn degradation was confirmed in the deep deposits near the water table. Under aerobic conditions, the high amounts of Cr, Mn, Ni, and Zn in deposits decreased the chemical degradation of terbutryn.

  10. Degradation and transformation of atrazine under catalyzed ozonation process with TiO2 as catalyst.

    Science.gov (United States)

    Yang, Yixin; Cao, Hongbin; Peng, Pai; Bo, Hongmiao

    2014-08-30

    Degradation of atrazine by heterogeneously catalyzed ozonation was carried out with TiO2 in the form of rutile as the catalyst. Some experimental factors such as catalyst dose, ozone dose and initial concentration of atrazine were investigated for their influence on catalyzed ozonation process. Although atrazine was effectively removed from aqueous solution by catalyzed ozonation process, the mineralization degree only reached 56% at the experimental conditions. Five transformation products were identified by GC/MS analysis. The degradation of atrazine involved de-alkylation, de-chlorination and de-amination. Diaminotriazine and 5-azauracil were the de-chlorinated and de-aminated products, respectively. The evolution of concentration of transformation products during catalyzed ozonation process was compared with uncatalyzed ozonation to show the degradation pathway. Toxicity tests based on the inhibition of the luminescence emitted by Vibrio fisheri indicated the detoxification of atrazine by catalyzed ozonation.

  11. Quantum efficiencies of the photo-Fenton degradation of atrazine in water.

    Science.gov (United States)

    Benzaquén, T B; Isla, M A; Alfano, O M

    2012-01-01

    An experimental work in a well-stirred batch recycling reactor for the photo-Fenton degradation of atrazine in water is presented. A study of the quantum efficiency is performed to assess the effectiveness of the photo-Fenton process on the atrazine degradation and total organic carbon (TOC) mineralization. Apparent and absolute quantum efficiencies of degradation and mineralization of an atrazine-based commercial herbicide are determined under different experimental conditions. Higher apparent efficiencies were found for both atrazine degradation and TOC mineralization when the ferric ion and hydrogen peroxide concentrations are increased. Because of the well known stability of the triazine ring, atrazine was not completely mineralized by the photo-Fenton process. However, a TOC reduction of 40% was achieved, being 62.5% of the maximum value that can be reached.

  12. Atrazine reduces reproduction in fathead minnow (Pimephales promelas): raw data report

    Science.gov (United States)

    Tillitt, Donald E.; Papoulias, Diana M.; Whyte, Jeffrey J.; Richter, Catherine A.

    2014-01-01

    The herbicide, atrazine, routinely is observed in surface and groundwaters, particularly in the “corn belt” region, a high-use area of the United States. Atrazine has demonstrated effects on reproduction in mammals and amphibians, but the characterization of endocrine-related effects in fish has received only limited attention. Peak concentrations of atrazine in surface water of streams from these agricultural areas coincide with annual spawning events of native fishes. Consequently, there was an unacceptable level of uncertainty in our understanding of the risks associated with the periods of greatest atrazine exposure and greatest vulnerability of certain species of fishes. For this reason, a study of the effects of atrazine on fathead minnow reproduction was undertaken (Tillitt and others, 2010). This report provides the raw data from that study.

  13. Sensitivity of a green alga to atrazine is not enhanced by previous acute exposure.

    Science.gov (United States)

    Baxter, Leilan; Brain, Richard; Prosser, Ryan; Solomon, Keith; Hanson, Mark

    2013-10-01

    Exposure to atrazine in small lotic systems can be episodic, with short-term pulses (peaks) followed by lower, decreasing concentrations. Algae and macrophytes recover rapidly from pulsed exposure to atrazine, but reported observations of population response to subsequent exposures are minimal and inconclusive. Consequently, the sensitivity of Pseudokirchneriella subcapitata to atrazine following a pulsed exposure was assessed. Exposure concentrations reflected amplifications of those observed in streams from highly vulnerable watersheds in regions of intense use. Initial pulsed atrazine exposure at 0, 150 or 300 μg/L for 24-h was followed by 72-h exposure to 0, 5, 10, 25, or 50 μg/L. Measured responses were cell density, growth rate, chlorophyll-a, and maximum quantum yield of photosystem II. Algal recovery was rapid and prior pulsed exposure to atrazine did not significantly affect subsequent sensitivity (EC10s, EC25s) for any endpoint, indicating no changes in tolerance at the population level for this species.

  14. Potential impacts of seasonal variation on atrazine and metolachlor persistence in andisol soil.

    Science.gov (United States)

    Jaikaew, Piyanuch; Boulange, Julien; Thuyet, Dang Quoc; Malhat, Farag; Ishihara, Satoru; Watanabe, Hirozumi

    2015-12-01

    To estimate the potential effect of seasonal variation on the fate of herbicides in andisol soil, atrazine and metolachlor residues were investigated through the summer and winter seasons during 2013 and 2014 under field condition. The computed half-lives of atrazine and metolachlor in soil changed significantly through the two seasons of the trial. The half-lives were shorter in summer season with 16.0 and 23.5 days for atrazine and metolachlor, respectively. In contrast, the half-lives were longer during the winter season with 32.7 and 51.8 days for atrazine and metolachlor, respectively. The analysis of soil water balance suggested that more pesticide was lost in deeper soil layers through infiltration in summer than in winter. In addition, during the summer season, metolachlor was more likely to leach into deeper soil layer than atrazine possibly due to high water solubility of metolachlor.

  15. Detoxification of Atrazine by Endophytic Streptomyces sp. Isolated from Sugarcane and Detection of Nontoxic Metabolite.

    Science.gov (United States)

    Mesquini, Josiane A; Sawaya, Alexandra C H F; López, Begonã G C; Oliveira, Valéria M; Miyasaka, Natalia R S

    2015-12-01

    Atrazine is still one of the most used agricultural pesticides worldwide and it has been recognized as a major contaminant of surface and ground water. The aims of this research were to isolate an endophytic microorganism from leaves of sugarcane, evaluate its ability to degrade atrazine, and investigate the formation of metabolites. By sequencing of the 16S rRNA gene, the endophytic isolate atz2 was identified as Streptomyces sp. The reduction in atrazine concentration by Streptomyces sp. atz2 was 98 % and UHPLC-MS/MS analyses showed the appearance of an unknown metabolite observed as m/z 311. Ecotoxicity tests with an aquatic organism, Daphnia similis, confirmed that this metabolite was nontoxic. This mechanism of detoxification of atrazine is different from the ones of other free-living microorganisms that inhabit the soil or rhizosphere. The results show new aspects of atrazine detoxification, highlighting a new role of endophytic bacteria in plants.

  16. Atrazine in a corn cultivated area and its relation with the landscape position

    Directory of Open Access Journals (Sweden)

    Regimeire Freitas Aquino

    2013-10-01

    Full Text Available Atrazine is still being used in no-till corn production in Brazil. This herbicide can be moved by overland flow and leached in the soil profile. In both ways, it can pollute water, either by reaching the groundwater or lakes and streams close to the crop field. This study evaluated the presence of atrazine in a dystrophic Yellow-Red Argisol and a dystrophic Melanic Gleisol in a corn field, where atrazine has been applied for 11 years. Overland flow was the main process of atrazine transport on hillslope and leaching was the most important process in the floodplain. Frequency and location of atrazine application in the landscape define this herbicide contamination process.

  17. Sorption of dissolved organic matter and its effects on the atrazine sorption on soils

    Institute of Scientific and Technical Information of China (English)

    LING Wan-ting; WANG Hai-zhen; XU Jian-ming; GAO Yan-zheng

    2005-01-01

    The dissolved organic matter(DOM), water soluble organic matter derived from sewage sludge was separated into hydrophobic fraction(Ho) and hydrophilic fraction(Hi). The sorption of DOM and its fractions on soils and the effects of DOM sorption on a nonionic pesticide(atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-trazine)) distribution between soil and water were investigated using a batch equilibrium technique. The total DOM sorption on soils described by the Langmuir equation reached saturation as the DOMconcentration increased. The sorption of Ho fit the Freundlich model. In contrast, a negative retention evidently occurred as adding Hi at higher level in tested soils. The sorption of Ho dominated the total DOM sorption and the release of soil organic matter(SOM). Effects of DOM on the atrazine sorption by soils were DOM-concentration dependent and dominated by the interaction of atrazine, DOM, and soil solids. Generally, the presence of DOM with lower concentration promoted atrazine sorption on soils, namely the apparent partitioning constant( K; ) for atrazine sorption in the presence of DOM was larger than the distribution constant ( Kd ) without DOM; whereas the presence of DOM with higher concentration inhibited atrazine sorption(i. e., K; < Kd ) . The overall effects of DOM on atrazine sorption in soils might be related to the DOM sorption and the release of soil intrinsic organic matter into aqueous solution. The sorption of Ho on soils promoted the atrazine sorption on soil, while the release of SOM by Hi and the competitive sorption between Hi and atrazine on soil surface led to a decrease of atrazine sorption. Information provided in this work may contribute to a better understanding of the DOM sorption and its impacts on the contaminant soil-water distribution.

  18. Enhanced degradation of atrazine under field conditions correlates with a loss of weed control in the glasshouse.

    Science.gov (United States)

    Krutz, L Jason; Zablotowicz, Robert M; Reddy, Krishna N; Koger, Clifford H; Weaver, Mark A

    2007-01-01

    Enhanced degradation of atrazine has been reported in the literature, indicating the potential for reduced residual weed control with this herbicide. Experiments were conducted to determine the field dissipation of atrazine in three cropping systems: continuous Zea mays L. (CC) receiving atrazine applications each year, Gossypium hirsutum L.-Z. mays rotation (CCR) receiving applications of atrazine once every 2 years and a no atrazine history soil (NAH). Subsequent laboratory and greenhouse experiments were conducted with soil collected from these cropping systems to determine atrazine degradation, mineralization and residual weed control. Field dissipation of atrazine followed first-order kinetics, and calculated half-life values for atrazine combined over 2003 and 2005 increased in the order of CC (9 d) = CCR (10 d) atrazine was approximately twofold greater in NAH soil than in CC or CCR soil. Biometer flask mineralization studies suggested that enhanced degradation of atrazine was due to rapid catabolism of the s-triazine ring. Glasshouse efficacy studies revealed a loss of residual weed control in CC and CCR soil compared with NAH soil. These data indicate that, under typical Mississippi Delta field conditions and agronomic practices, the persistence of atrazine may be reduced by at least 50% if the herbicide is applied more than once every 24 months. Glasshouse studies suggest that under these conditions a loss of residual weed control is possible.

  19. Competitive fluorescence assay for specific recognition of atrazine by magnetic molecularly imprinted polymer based on Fe3O4-chitosan.

    Science.gov (United States)

    Liu, Guangyang; Li, Tengfei; Yang, Xin; She, Yongxin; Wang, Miao; Wang, Jing; Zhang, Min; Wang, Shanshan; Jin, Fen; Jin, Maojun; Shao, Hua; Jiang, Zejun; Yu, Hailong

    2016-02-10

    A novel fluorescence sensing strategy for determination of atrazine in tap water involving direct competition between atrazine and 5-(4,6-dichlorotriazinyl) aminofluorescein (5-DTAF), and which exploits magnetic molecularly imprinted polymer (MMIP), has been developed. The MMIP, based on Fe3O4-chitosan nanoparticles, was synthesized to recognize specific binding sites of atrazine. The recognition capability and selectivity of the MMIP for atrazine and other triazine herbicides was investigated. Under optimal conditions, the competitive reaction between 5-DTAF and atrazine was performed to permit quantitation. Fluorescence intensity changes at 515 nm was linearly related to the logarithm of the atrazine concentration for the range 2.32-185.4 μM. The detection limit for atrazine was 0.86μM (S/N=3) and recoveries were 77.6-115% in spiked tap water samples.

  20. Review of Toxicology of Atrazine and Chlorpyrifos on Fish

    Institute of Scientific and Technical Information of China (English)

    WANG Xu; LI Jilong; XING Houjuan; XU Shiwen

    2011-01-01

    Atrazine (ATR) and chlorpyrifos (CPF) are widely used in agriculture, but have resulted in a series of toxicological and environmental problems. They were heavily used which have potential threat to fish and rodents. Several recent laboratory studies have shown ATR and CPF could lead to oxidative damage, immunocyte reduced and inhibit acetylcholinesterase (ACHE). In order to clarify the toxicity of ATR and CPF, this paper summarized the adverse effects of ATR and CPF on reproduction, nerve and immune systems in fish.

  1. Wire-cylinder dielectric barrier discharge induced degradation of aqueous atrazine.

    Science.gov (United States)

    Zhu, Dan; Jiang, Lin; Liu, Run-Long; Chen, Pei; Lang, Lin; Feng, Jing-Wei; Yuan, Shou-Jun; Zhao, Da-Yong

    2014-12-01

    The wire-cylinder dielectric barrier discharge reactor was adopted for removal of aqueous atrazine. The effect of different parameters on the degradation efficiency of atrazine was investigated, and the degradation mechanism of atrazine was studied. The experimental results showed that when the discharge power was 50 W and the air flow rate was 140 L h(-1), 93.7% of atrazine was degraded after 18 min of discharge time. The concentrations of generated O3 and H2O2 increased with increasing discharge time. The pH decreased from 6.80 to 2.50, 12.7% of TOC was removed after 18 min. The concentrations of generated Cl(-) and NO3(-) increased significantly during the degradation process of atrazine, and the decreasing toxicity trend was observed for the treated atrazine solution. The degradation byproducts of atrazine were identified using liquid chromatography-time-of-flight mass spectrometry (LC-TOF-MS), which might be formed mainly in dechlorination hydroxylation, alkyl oxidation, dechlorination hydroxylation combined with alkyl oxidation and demethylation oxidation reactions.

  2. Differential morphological effects in rat corpora lutea among ethylene glycol monomethyl ether, atrazine, and bromocriptine.

    Science.gov (United States)

    Taketa, Yoshikazu; Inoue, Kaoru; Takahashi, Miwa; Yamate, Jyoji; Yoshida, Midori

    2013-07-01

    Ethylene glycol monomethyl ether (EGME) or atrazine induces luteal cell hypertrophy in rats. Our previous study suggested that EGME stimulates both new and old corpora lutea (CL), while atrazine stimulates new CL. Bromocriptine (BRC) is known to suppress the luteolysis in rats. This study investigated the light- and electron-microscopic luteal changes induced by EGME, atrazine, or BRC. Female rats were treated with EGME (300 mg/kg/day), BRC (2 mg/kg/day), EGME and BRC (EGME + BRC), or atrazine (300 mg/kg/day) for 7 days. Luteal cell hypertrophy induced by EGME, EGME + BRC, and atrazine was subclassified into the following two types: CL hypertrophy, vacuolated type (CL-V) characterized by intracytoplasmic fine vacuoles, and CL hypertrophy, eosinophilic type (CL-E) characterized by eosinophilic and abundant cytoplasm. The proportions of CL-V and CL-E were different among the treatments. BRC-treated old CL showed lower proportion of endothelial cells and fibroblasts than normal old CL. Ultrastructural observation revealed that the luteal cells of CL-V contained abundant lipid droplets, whereas those of CL-E in EGME and EGME + BRC groups showed uniformly well-developed smooth endoplasmic reticulum. No clear ultrastructural difference was observed between the control CL and atrazine-treated CL-E. These results indicate that EGME, atrazine, and BRC have differential luteal morphological effects.

  3. Twenty years of long-term Atrazine monitoring in a shallow aquifer in Western Germany (Invited)

    Science.gov (United States)

    Vereecken, H.; Vonberg, D.; Putz, T.; Vanderborght, J.

    2013-12-01

    Atrazine, one of the most frequent applied pesticides worldwide, was banned in Germany in 1991 due to exceeded threshold values in ground- and drinking waters. Monitoring of atrazine was hence introduced in the Zwischenscholle aquifer, exposed to intensive agricultural land use and susceptible to contaminants due to a shallow water table. In total 60 observation wells were monitored since 1991, of which 11 are sampled monthly today. Descriptive statistics of monitoring data were derived using the 'regression on order statistics' (ROS) data censoring approach, estimating values for nondetects. The monitoring data shows that even 20 years after the ban of atrazine, the concentrations in groundwater are on a constant level without any considerable decrease. The spatial distribution of atrazine concentrations is highly heterogeneous with observation wells exhibiting constantly concentrations above the threshold on the one hand and observation wells where concentrations are frequently below the limit of quantification (LOQ) on the other hand. A deethylatrazine-to-atrazine ratio (DAR) was used to distinguish between diffuse - and point-source contamination, with a global mean value of 0.84 indicating mainly diffuse contamination. Principle Component Analysis (PCA) was applied to the monitoring dataset and relationships of triazine compounds became obvious. Accordingly the metabolite desisopropylatrazine was exclusively associated with the occurrence of the parent compound simazine and not atrazine, whereas deethylatrazine was clearly related to atrazine.

  4. Transcriptome analysis of Glomus mosseae/Medicago sativa mycorrhiza on atrazine stress.

    Science.gov (United States)

    Song, Fuqiang; Li, Jize; Fan, Xiaoxu; Zhang, Quan; Chang, Wei; Yang, Fengshan; Geng, Gui

    2016-02-02

    Arbuscular mycorrhizal fungi (AMF) protect host plants against diverse biotic and abiotic stresses, and promote biodegradation of various contaminants. In this study effect of Glomus mosseae/Medicago sativa mycorrhiza on atrazine degradation was investigated. It was observed that the atrazine degradation rates with any addition level in mycorrhizal treatments were all significantly higher than those in non-mycorrhizal treatments. When atrazine was applied at 20 mg kg(-1), the removal efficiency was up to 74.65%. Therefore, G. mosseae can be considered as ideal inhabitants of technical installations to facilitate phytoremediation. Furthermore, a total of 10.4 Gb was used for de novo transcriptome assembly, resulting in a comprehensive data set for the identification of genes corresponding to atrazine stress in the AM association. After comparative analysis with edgeR, a total of 2,060 differential expressed genes were identified, including 570 up-regulated genes and 1490 down-regulated genes. After excluding 'function unknown' and 'general function predictions only' genes, 172 up-regulated genes were obtained. The differentially expressed genes in AM association with and without atrazine stress were associated with molecular processes/other proteins, zinc finger protein, intracellular/extracellular enzymes, structural proteins, anti-stress/anti-disease protein, electron transport-related protein, and plant growth associated protein. Our results not only prove AMF has important ecological significance on atrazine degradation but also provide evidence for the molecular mechanisms of atrazine degradation by AMF.

  5. Study of atrazine degradation in subsurface flow constructed wetland under different salinity.

    Science.gov (United States)

    Lin, Tao; Wen, Yue; Jiang, Lingyan; Li, Jianbo; Yang, Silu; Zhou, Qi

    2008-05-01

    To evaluate the treatment capability of subsurface flow constructed wetland (SFCW) and the effect of salinity on the degradation of atrazine, the degradation of atrazine in SFCW was studied. Under the static condition, the degradation of atrazine in SFCW followed first-order kinetics: c=0.09679 exp(-0.0396t) (c, residue concentration, mg l(-1); t, retention time, d), with a half-life of approximately 17.5 days. The atrazine degradation kinetic functions were established for salinities of 1.5, 3.0, 5.0, 10.0 and 15.0 g l(-1), respectively, which appeared to approach first-order kinetics. The effect of salinity on the atrazine treatment efficiency showed an exponential inhibition: lnk=3.204+0.04991 C (k, degradation constant; C, NaCl concentration, mg l(-1)). The attenuation of atrazine in SFCW cannot be a result of hydrolysis or sorption process. It was considered that some bacteria in the wetland system degraded atrazine into deethylatrazine (DEA) and deisopropylatrazine (DIA) and sequentially into CO(2) and H(2)O. Salinity impacted on the growth of bacteria resulting in a switch of the microbial community. With the increase of salinity, Shannon-Wiener Diversity Index in the SFCW system declined. The relationship between atrazine degradation constant (k) and Shannon Index was established as shown in linear phase, y=-0.07286+0.0363x. The positive correlation between them indicated that microbial community played an important role in the atrazine degradation process.

  6. 20 years of long-term atrazine monitoring in a shallow aquifer in western Germany.

    Science.gov (United States)

    Vonberg, David; Vanderborght, Jan; Cremer, Nils; Pütz, Thomas; Herbst, Michael; Vereecken, Harry

    2014-03-01

    Atrazine was banned in Germany in 1991 due to findings of atrazine concentrations in ground- and drinking waters exceeding threshold values. Monitoring of atrazine concentrations in the groundwater since then provides information about the resilience of the groundwater quality to changing agricultural practices. In this study, we present results of a monitoring campaign of atrazine concentrations in the Zwischenscholle aquifer. This phreatic aquifer is exposed to intensive agricultural land use and susceptible to contaminants due to a shallow water table. In total 60 observation wells (OWs) have been monitored since 1991, of which 15 are sampled monthly today. Descriptive statistics of monitoring data were derived using the "regression on order statistics" (ROS) data censoring approach, estimating values for nondetects. The monitoring data shows that even 20 years after the ban of atrazine, the groundwater concentrations of sampled OWs remain on a level close to the threshold value of 0.1 μg l(-1) without any considerable decrease. The spatial distribution of atrazine concentrations is highly heterogeneous with OWs exhibiting permanently concentrations above the regulatory threshold on the one hand and OWs were concentrations are mostly below the limit of quantification (LOQ) on the other hand. A deethylatrazine-to-atrazine ratio (DAR) was used to distinguish between diffuse - and point-source contamination, with a global mean value of 0.84 indicating mainly diffuse contamination. Principle Component Analysis (PCA) of the monitoring dataset demonstrated relationships between the metabolite desisopropylatrazine, which was found to be exclusively associated with the parent compound simazine but not with atrazine, and between deethylatrazine, atrazine, nitrate, and the specific electrical conductivity. These parameters indicate agricultural impacts on groundwater quality. The findings presented in this study point at the difficulty to estimate mean concentrations

  7. Sorption and distribution of aged atrazine residues in the drainage system of an outdoor lysimeter experiment

    Science.gov (United States)

    Jablonowski, N. D.; Schäffer, A.; Burauel, P.

    2009-04-01

    Even though the environmental impact of the herbicide atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] is a matter of controversy, it is still extensively applied for agricultural purposes. Particularly in the US, atrazine has been applied to approximately 70% of all corn acreages in the last 18 years. Atrazine is banned in the EU but its use is increasing in countries like China, Brazil and India. Therefore, the worldwide soil burden of this compound must be enormous. Atrazine has been found to be highly persistent in the environment and it has been suggested that it is moderately mobile in the soil profile. As a result, it is found in most groundwater aquifers and surface waters in agricultural areas in the US. Even in Germany, where it was prohibited in 1991, it is still found in groundwater wells below agriculturally used land where it was formerly applied. For a long-term outdoor lysimeter experiment with a disturbed soil column, a drainage system of fine gravel was originally embedded at the bottom of the lysimeter. In this drainage system, atrazine and its metabolite 2-hydroxy-atrazine were extracted as long as 22 years after the last atrazine application. Due to the radiolabelling, the spatial distribution of the atrazine residues can be evaluated in fractions like fine clay particles attached to the gravel or in the gravel itself. Approximately 2% of the total gravel consisted of carbonaceous, slag-like particles which might retain most of the atrazine and its residues. The latest data will be presented at the session.

  8. Degradation of atrazine by UV/chlorine: Efficiency, influencing factors, and products.

    Science.gov (United States)

    Kong, Xiujuan; Jiang, Jin; Ma, Jun; Yang, Yi; Liu, Weili; Liu, Yulei

    2016-03-01

    In this work, the degradation of atrazine by the combination of UV and chlorine (UV/chlorine) due to the formation of radicals during chlorine photolysis was systematically investigated in terms of efficiency, factors that influence the degradation kinetics, as well as oxidation products. It was found that the degradation efficiency of atrazine was enhanced by UV/chlorine compared to UV or chlorine alone. The degradation efficiency of atrazine was favorable at a lower pH, but was inhibited in the presence of natural organic matters. Meanwhile, the initial chlorine dosage, alkalinity, and chloride barely influenced the degradation efficiency under neutral pH conditions. The degradation of atrazine by UV/chlorine was inhibited in real waters (i.e., surface water and ground water) compared to in deionized water but was still more effective than UV alone. The oxidation products of atrazine resulting from de-alkylation, dechlorination-hydroxylation, alkylic-hydroxylation, alkylic-oxidation, alkylic-hydroxylation-dehydration, deamination-hydroxylation, and dechlorination-hydrogenation in UV/chlorine process were detected, which were slightly different from those formed in UV/H2O2 (commonly used UV-based advanced oxidation process). Particularly, the yields of three primary transformation products (desethyl-atrazine (DEA), desisopropyl-atrazine (DIA), and desethyl-desisopropyl-atrazine (DEIA)) were comparatively quantified in these two processes. The different trend of them formed in UV/chlorine system (DEA:DIA≈4) compared to that formed in UV/H2O2 system (DEA:DIA≈1) could be ascribed to the different reaction reactivities and mechanisms between HO• and Cl• with atrazine.

  9. Multiple Beamforming with Perfect Coding

    CERN Document Server

    Li, Boyu

    2011-01-01

    In Singular Value Decomposition (SVD) beamforming, without channel coding, there is a trade-off between full diversity and full multiplexing. Adding channel coding, full diversity and full multiplexing can be both achieved, as long as the code rate Rc and the number of subchannels S satisfy RcS1. Recently discovered Perfect Space-Time Block Codes (PSTBCs) are full-rate full-diversity space-time codes, achieving maximum coding gain. In this paper, two novel techniques, Perfect Coded Multiple Beamforming (PCMB) and Bit-Interleaved Coded Multiple Beamforming with Perfect Coding (BICMB-PC), are proposed, employing PSTBCs. PCMB achieves full diversity, full multiplexing, and full rate simultaneously, and its performance is close to PSTBC and FPMB, while the decoding complexity is significantly less than PSTBC and much lower than FPMB of dimensions 2 and 4. On the other hand, BICMB-PC achieves both full diversity and full multiplexing, and its performance is similar to BICMB-FP, but provides much lower decoding com...

  10. Effect of organic amendments on degradation of atrazine.

    Science.gov (United States)

    Mukherjee, Irani

    2009-12-01

    Pesticide contamination of soil and ground water at or near the agricultural fields is a major problem world wide. The ability of several amendments like rice straw, manure, saw dust and charcoal were used to stimulate the degradation of atrazine in soil. Field soil fortified with pesticide at two concentration levels were amended separately with rice straw, farm yard manure, saw dust and charcoal at rates of 2.5% (w/w) and maintained at field capacity moisture regime and kept at ambient temperature 25 +/- 5 degrees C. The results indicate 89.5% degradation of atrazine in farm yard manure during 60-day period followed by rice straw, saw dust charcoal and recording 87.2% and 83.8%, 67.7%, respectively, as compared to unamended treatment where 63.3% degradation was observed. The FYM was found to be most effective in soil and enhances the degradation as compared to the other amendments. Although addition of organic manures has been an integral part of sustainable agriculture practices; the present findings give a new dimension of it's utilization for removal of persistent pesticides.

  11. Effects of Cu(Ⅱ) and humic acid on atrazine photodegradation

    Institute of Scientific and Technical Information of China (English)

    Xia Sun; Hui Liu; Yaobin Zhang; Yazhi Zhao; Xie Quan

    2011-01-01

    This work was designed to explore the characteristics of photodegradation of herbicides in the copper-polluted water body.The results showed that Cu(Ⅱ) alone could induce a photo Fenton-like reaction to enhance the degradation of atrazine, in which hydroxyl radical (·OH) was a main active species.Humic acids restrained atrazine degradation, nevertheless, when introducing Cu(Ⅱ), the photodegradation was accelerated, in which singlet oxygen (1O2) replaced OH acting as the prevailing species.A feasible mechanism for the photochemical process was also proposed, which is helpful for better understanding the environmental photochemistry of atrazine in the copper-polluted water.

  12. PC 2 Phone Event Announcer

    CERN Document Server

    Parhizkar, Behrang; Ali, Mohammad Nabil Sadegh; Ramachandran, Anand; Navaratnam, Sujata

    2010-01-01

    Nowadays, mobile phones are indispensable devices; it has become a trend now that college and university students are owners of such devices and this particular factor plays a very important role behind the coming up with the proposed system. "PC 2 Phone event Announcer", is the name of the new proposed system suggested to solve the existing communication problem between the College staff and students. As the name suggests, it can be deduced that the system will involve computers and phones, more specifically mobile phones.

  13. Data acquisition techniques using PC

    CERN Document Server

    Austerlitz, Howard

    1991-01-01

    Data Acquisition Techniques Using Personal Computers contains all the information required by a technical professional (engineer, scientist, technician) to implement a PC-based acquisition system. Including both basic tutorial information as well as some advanced topics, this work is suitable as a reference book for engineers or as a supplemental text for engineering students. It gives the reader enough understanding of the topics to implement a data acquisition system based on commercial products. A reader can alternatively learn how to custom build hardware or write his or her own software.

  14. Photochemical degradation of atrazine in UV and UV/H2O2 process: pathways and toxic effects of products.

    Science.gov (United States)

    Choi, Hyun-Jin; Kim, Daekeun; Lee, Tae-Jin

    2013-01-01

    The degradation of atrazine in aqueous solution by UV or UV/H2O2 processes, and the toxic effects of the degradation products were explored. The mineralization of atrazine was not observed in the UV irradiation process, resulting in the production of hydroxyatrazine (OIET) as the final product. In the UV/H2O2 process, the final product was ammeline (OAAT), which was obtained by two different pathways of reaction: dechlorination followed by hydroxylation, and the de-alkylation of atrazine. The by-products of the reaction of dechlorination followed by hydroxylation were OIET and hydroxydeethyl atrazine (OIAT), and those of de-alkylation were deisopropyl atrazine (CEAT), deethyl atrazine (CIAT), and deethyldeisopropyl atrazine (CAAT). OIAT and OAAT appeared to be quite stable in the degradation of atrazine by the UV/H2O2 process. In a toxicity test using Daphnia magna, the acute toxic unit (TUa) was less than 1 of TUa (100/EC50, %) in the UV/H2O2 process after 30 min of reaction time, while 1.2 to 1.3 of TUa was observed in the UV process. The TUa values of atrazine and the degradation products have the following decreasing order: OIET> Atrazine> CEAT≈CIAT> CAAT. OIAT and OAAT did not show any toxic effects.

  15. Effects of Short Term Exposure of Atrazine on the Liver and Kidney of Normal and Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Dinesh Babu Jestadi

    2014-01-01

    Full Text Available The present study evaluates the effects of short term (15 days exposure of low dose (300 μg kg−1 of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine on antioxidant status and markers of liver and kidney damage in normal (nondiabetic and diabetic male Wistar rats. Rats were divided into four groups: Group I as normal control, Group II as atrazine treated, Group III as diabetic control, and Group IV as atrazine treated diabetic rats. Atrazine administration resulted in increased MDA concentration as well as increased activities of SOD, CAT, and GPx in both liver and kidney of atrazine treated and atrazine treated diabetic rats. However, GSH level was decreased in both liver and kidney of atrazine treated and atrazine treated diabetic rats. Atrazine administration led to significant increase in liver damage biomarkers such as AST, ALT, and ALP as well as kidney damage biomarkers such as creatinine and urea in both normal and diabetic rats, but this increase was more pronounced in diabetic rats when compared to normal rats. In conclusion, the results of the present study demonstrate that short term exposure of atrazine at a dose of 300 μg kg−1 could potentially induce oxidative damage in liver and kidney of both normal and diabetic rats.

  16. Characterization of bacterial diversity in an atrazine degrading enrichment culture and degradation of atrazine, cyanuric acid and biuret in industrial wastewater.

    Science.gov (United States)

    Dutta, Anirban; Vasudevan, Venugopal; Nain, Lata; Singh, Neera

    2016-01-01

    An enrichment culture was used to study atrazine degradation in mineral salt medium (MSM) (T1), MSM+soil extract (1:1, v/v) (T2) and soil extract (T3). Results suggested that enrichment culture required soil extract to degrade atrazine, as after second sequential transfer only partial atrazine degradation was observed in T1 treatment while atrazine was completely degraded in T2 and T3 treatments even after fourth transfer. Culture independent polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technique confirmed selective enrichment of genus Bacillus along with Pseudomonas and Burkholderia. Degradation of atrazine/metabolites in the industrial wastewater was studied at different initial concentrations of the contaminants [wastewater-water (v/v) ratio: T1, 1:9; T2, 2:8; T3, 3:7; T4, 5:5 and T5, undiluted effluent]. The initial concentrations of atrazine, cyanuric acid and biuret ranged between 5.32 and 53.92 µg mL(-1), 265.6 and 1805.2 µg mL(-1) and 1.85 and 16.12 µg mL(-1), respectively. The enrichment culture was able to completely degrade atrazine, cyanuric acid and biuret up to T4 treatment, while no appreciable degradation of contaminants was observed in the undiluted effluent (T5). Inability of enrichment culture to degrade atrazine/metabolites might be due to high concentrations of cyanuric acid. Therefore, a separate study on cyanuric acid degradation suggested: (i) no appreciable cyanuric acid degradation with accumulation of an unidentified metabolite in the medium where cyanuric acid was supplemented as the sole source of carbon and nitrogen; (ii) partial cyanuric acid degradation with accumulation of unidentified metabolite in the medium containing additional nitrogen source; and (iii) complete cyanuric acid degradation in the medium supplemented with an additional carbon source. This unidentified metabolite observed during cyanuric acid degradation and also detected in the enrichment culture inoculated wastewater samples

  17. PC-BLAS. PC Basic Linear Algebra Subroutines

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, R.J. [Sandia National Labs., Albuquerque, NM (United States)

    1986-11-01

    PC-BLAS is a highly optimized version of the Basic Linear Algebra Subprograms (BLAS), a standardized set of thirty-eight routines that perform low-level operations on vectors of numbers in single and double-precision real and complex arithmetic. Routines are included to find the index of the largest component of a vector, apply a Givens or modified Givens rotation, multiply a vector by a constant, determine the Euclidean length, perform a dot product, swap and copy vectors, and find the norm of a vector. The BLAS have been carefully written to minimize numerical problems such as loss of precision and underflow and are designed so that the computation is independent of the interface with the calling program. This independence is achieved through judicious use of Assembly language macros. Interfaces are provided for Lahey Fortran 77, Microsoft Fortran 77, and Ryan-McFarland IBM Professional Fortran.

  18. Degradation of atrazine by microwave-assisted electrodeless discharge mercury lamp in aqueous solution.

    Science.gov (United States)

    Ta, Na; Hong, Jun; Liu, Tingfeng; Sun, Cheng

    2006-11-02

    The present study investigates the degradation of atrazine (2-chloro-4-(ethyl amino)-6-isopropyl amino-s-triazine) in aqueous solution by a developed new method, namely by means of a microwave-assisted electrodeless discharge mercury lamp (MW-EDML). An experimental design was conducted to assess the influence of various parameters: pH value, initial concentration, amount of EDML, initial volume and coexisted solvent. Atrazine was degraded completely by EDML in a relatively short time (i.e. t(1/2)=1.2 min for 10 mg/l). Additionally, the identification of main degradation products during atrazine degradation process was conducted by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). This study proposes the degradation mechanism including four possible pathways for atrazine degradation according to the degradation products.

  19. Degradation of atrazine in aqueous medium by electrocatalytically generated hydroxyl radicals. A kinetic and mechanistic study.

    Science.gov (United States)

    Balci, Beytul; Oturan, Nihal; Cherrier, Richard; Oturan, Mehmet A

    2009-04-01

    Oxidative degradation of atrazine by hydroxyl radicals (()OH) was studied in aqueous medium. ()OH were formed in situ from electrochemically generating Fenton's reagent by an indirect electrochemical advanced oxidation process. Identification and evolution of seven main aromatic metabolites and four short-chain carboxylic acids were performed by using liquid chromatography analyses. Total organic carbon (TOC) and ionic chromatography were used in order to evaluate the mineralization efficiency of treated aqueous solutions. A high mineralization rate of 82% (never reported until now) was obtained. The oxidative degradation of cyanuric acid, the ultimate product of atrazine degradation, was highlighted for the first time. The absolute rate constant of the reaction between atrazine and hydroxyl radicals was evaluated by competition kinetics method as (2.54+/-0.22)x10(9)M(-1)s(-1). Considering all oxidation reaction intermediates and end products a general reaction sequence for atrazine degradation by hydroxyl radicals was proposed.

  20. Effective photocatalytic degradation of atrazine over titania-coated carbon nanotubes (CNTs) coupled with microwave energy.

    Science.gov (United States)

    Chen, Hongzhe; Yang, Shaogui; Yu, Kai; Ju, Yongming; Sun, Cheng

    2011-04-14

    Microwave-assisted photocatalytic (MAPC) degradation of atrazine over nanotitania coated multiwalled carbon nanotubes (TiO(2)/MWCNTs) was investigated in this study. As a result, degradation efficiency of atrazine over TiO(2)/CNTs prepared by hydrothermal method was about 30% and 20% higher than that of titania P25 and anatase prepared hydrothermally in given time. The TiO(2)/CNTs composite samples were characterized by TGA-DSC, TEM, UV-vis DRS, XRD and BET, to explain the reason for efficient degradation and adsorption process of atrazine. Microwave thermal effect in this process was also investigated. Intermediates of degradation both in MAPC process and microwave-assisted photodegradation (MAPD) process were identified by LC/MS. It suggests that MWCNTs have special effects on atrazine degradation during MAPC process, like strong microwave absorption capability.

  1. The impact of atrazine on several biochemical properties of chernozem soil

    Directory of Open Access Journals (Sweden)

    LJ. RADIVOJEVIC

    2008-10-01

    Full Text Available The impact of the pesticide atrazine on biochemical processes in soil was investigated. Atrazine loadings of 8.0, 40.0 and 80.0 mg/kg soil were laboratory tested in an experiment set up on a clay loam soil. Dehydrogenase activity, change in biomass carbon, soil respiration and metabolic coefficient were examined. The samples were collected for analysis 1, 7, 14, 21, 30 and 60 days after atrazine application. The acquired data indicated that the effect of atrazine on the biochemical activity of the soil depended on its application rate and duration of activity, and the effect was either stimulating or inhibiting. However, the detected changes were found to be transient, indicating that there is no real risk of the compound disrupting the balance of biochemical processes in soil.

  2. Watershed regressions for pesticides (WARP) for predicting atrazine concentration in Corn Belt streams

    Science.gov (United States)

    Stone, Wesley W.; Gilliom, Robert J.

    2011-01-01

    Watershed Regressions for Pesticides (WARP) models, previously developed for atrazine at the national scale, can be improved for application to the U.S. Corn Belt region by developing region-specific models that include important watershed characteristics that are influential in predicting atrazine concentration statistics within the Corn Belt. WARP models for the Corn Belt (WARP-CB) were developed for predicting annual maximum moving-average (14-, 21-, 30-, 60-, and 90-day durations) and annual 95th-percentile atrazine concentrations in streams of the Corn Belt region. All streams used in development of WARP-CB models drain watersheds with atrazine use intensity greater than 17 kilograms per square kilometer (kg/km2). The WARP-CB models accounted for 53 to 62 percent of the variability in the various concentration statistics among the model-development sites.

  3. Characterization of an atrazine molecularly imprinted polymer prepared by a cooling method

    Science.gov (United States)

    Royani, Idha; Widayani, Abdullah, Mikrajuddin; Khairurrijal

    2014-03-01

    A molecularly imprinted polymer (MIP) for atrazine was successfully prepared. Atrazine molecules as templates were incorporated into the pre-polymerization solution containing a functional monomer (methacrylic acid), a cross-linker (ethylene glycol dimethacrylate), and an initiator (benzoyl peroxide). The placement of a tube containing the pre-polymerization solution into a freezer was done to replace nitrogen pouring into the pre-polymerization solution. The sensing characteristic of the obtained MIP was examined and it was found that the amount of atrazine bound to the cavities in the MIP increases with increasing the initial concentration of atrazine. From Scatchard plots, it was found that the equilibrium dissociation constant KD and the apparent maximum number of binding sites Bmax, which are written as (KD, Bmax), are (6.4 μM, 13.41 mmol/g) and (6.5 μM, 4.55 mmol/g) for the 10 and 30 mg of MIP, respectively.

  4. Using polymer mats to biodegrade atrazine in groundwater: laboratory column experiments

    Science.gov (United States)

    Patterson, B. M.; Franzmann, P. D.; Davis, G. B.; Elbers, J.; Zappia, L. R.

    2002-02-01

    Large-scale column experiments were undertaken to evaluate the potential of in situ polymer mats to deliver oxygen into groundwater to induce biodegradation of the pesticides atrazine, terbutryn and fenamiphos contaminating groundwater in Perth, Western Australia. The polymer mats, composed of woven silicone (dimethylsiloxane) tubes and purged with air, were installed in 2-m-long flow-through soil columns. The polymer mats proved efficient in delivering dissolved oxygen to anaerobic groundwater. Dissolved oxygen concentrations increased from biodegradation rates, suggesting that organic carbon was not limiting biodegradation. Atrazine degradation rates estimated in the column experiments were similar to rates determined in laboratory culture experiments, using pure cultures of atrazine-mineralising bacteria. No significant degradation of terbutryn or fenamiphos was observed under the experimental conditions within the time frames of the study. Results from these experiments indicate that remediation of atrazine in a contaminated aquifer may be achievable by delivery of oxygen using an in situ polymer mat system.

  5. Agrobacterium-mediated Transformation of Rice (Oryza sativa L.) with Atrazine Chlorohydrolase Gene (atzA)

    Institute of Scientific and Technical Information of China (English)

    WANG Song-wen; SHI Li-li; SUN Zong-xiu; CAI Bao-li; FU Ya-ping; WANG Yang; SI Hua-min; LIU Xia; ZHANG Xin

    2005-01-01

    Atrazine chlorohydrolase gene (atzA) was cloned from Arthrobacter sp. AD1. A plant expression plasmid was constructed under the control of CaMV35s promoter and was used in rice transformation. The target gene was successfully introduced into mature embryos of a japonica rice cultivar Jindao 107 by Agrobacterium- mediated transformation and hundreds of transgenic plants were obtained. The exogenous atzA gene in the transgenic plants that expressed atrazine resistance was confirmed by Southern blot hybridization. The resistance experiments by spraying transgenic rice plants with 0.133% atrazine shown that most of the transgenic rice plants exhibited the resistance to herbicide atrazine. The segregation of exogenous atzA gene in T1 progeny corresponded to the Mendelian ratio.

  6. PC/104 Embedded IOCs at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Jianxun Yan, Trent Allison, Sue Witherspoon, Anthony Cuffe

    2009-10-01

    Jefferson Lab has developed embedded IOCs based on PC/104 single board computers (SBC) for low level control systems. The PC/104 IOCs run EPICS on top of the RTEMS operating system. Two types of control system configurations are used in different applications, PC/104 SBC with commercial PC/104 I/O cards and PC/104 SBC with custom designed FPGA-based boards. RTEMS was built with CEXP shell to run on the PC/104 SBC. CEXP shell provides the function of dynamic object loading, which is similar to the widely used VxWorks operating system. Standard software configurations were setup for PC/104 IOC application development to provide a familiar format for new projects as well as ease the conversion of applications from VME based IOCs to PC/104 IOCs. Many new projects at Jefferson Lab are going to employ PC/104 SBCs as IOCs and some applications have already been running them for accelerator operations. The PC/104 - RTEMS IOC provides a free open source Real-Time Operating System (RTOS), low cost/maintenance, easily installed/ configured, flexible, and reliable solution for accelerator control and 12GeV Upgrade projects.

  7. Atrazine degradation by aerobic microorganisms isolated from the rhizosphere of sweet flag (Acorus calamus L.).

    Science.gov (United States)

    Marecik, Roman; Króliczak, Paweł; Czaczyk, Katarzyna; Białas, Wojciech; Olejnik, Anna; Cyplik, Paweł

    2008-04-01

    In presented study the capability of microorganisms isolated from the rhizosphere of sweet flag (Acorus calamus) to the atrazine degradation was assessed. Following isolation of the microorganisms counts of psychrophilic bacteria, mesophilic bacteria and fungi were determined. Isolated microorganisms were screened in terms of their ability to decompose a triazine herbicide, atrazine. Our results demonstrate that within the rhizosphere of sweet flag there were 3.8x10(7) cfu of psychrophilic bacteria, 1.8x10(7) cfu of mesophilic bacteria, and 6x10(5) cfu of fungi per 1 g of dry root mass. These microorganisms were represented by more than 20 different strains, and at the first step these strains were grown for 5 days in the presence of atrazine at a concentration of 5 mg/l. In terms of the effect of this trial culture, the bacteria reduced the level of atrazine by an average of about 2-20%, but the average level of reduction by fungi was in the range 18-60%. The most active strains involved in atrazine reduction were then selected and identified. These strains were classified as Stenotrophomonas maltophilia, Bacillus licheniformis, Bacillus megaterium, Rahnella aquatilis (three strains), Umbelopsis isabellina, Volutella ciliata and Botrytis cinerea. Culturing of the microorganisms for a longer time resulted in high atrazine degradation level. The highest degradation level was observed at atrazine concentrations of 5 mg/l for S. maltophilia (83.5% after 15 days of culture) and for Botrytis sp. (82% after 21 days of culture). Our results indicate that microorganisms of the sweet flag rhizosphere can play an important role in the bioremediation of atrazine-contaminated sites.

  8. Demasculinization and feminization of male gonads by atrazine: consistent effects across vertebrate classes.

    Science.gov (United States)

    Hayes, Tyrone B; Anderson, Lloyd L; Beasley, Val R; de Solla, Shane R; Iguchi, Taisen; Ingraham, Holly; Kestemont, Patrick; Kniewald, Jasna; Kniewald, Zlatko; Langlois, Valerie S; Luque, Enrique H; McCoy, Krista A; Muñoz-de-Toro, Mónica; Oka, Tomohiro; Oliveira, Cleida A; Orton, Frances; Ruby, Sylvia; Suzawa, Miyuki; Tavera-Mendoza, Luz E; Trudeau, Vance L; Victor-Costa, Anna Bolivar; Willingham, Emily

    2011-10-01

    Atrazine is the most commonly detected pesticide contaminant of ground water, surface water, and precipitation. Atrazine is also an endocrine disruptor that, among other effects, alters male reproductive tissues when animals are exposed during development. Here, we apply the nine so-called "Hill criteria" (Strength, Consistency, Specificity, Temporality, Biological Gradient, Plausibility, Coherence, Experiment, and Analogy) for establishing cause-effect relationships to examine the evidence for atrazine as an endocrine disruptor that demasculinizes and feminizes the gonads of male vertebrates. We present experimental evidence that the effects of atrazine on male development are consistent across all vertebrate classes examined and we present a state of the art summary of the mechanisms by which atrazine acts as an endocrine disruptor to produce these effects. Atrazine demasculinizes male gonads producing testicular lesions associated with reduced germ cell numbers in teleost fish, amphibians, reptiles, and mammals, and induces partial and/or complete feminization in fish, amphibians, and reptiles. These effects are strong (statistically significant), consistent across vertebrate classes, and specific. Reductions in androgen levels and the induction of estrogen synthesis - demonstrated in fish, amphibians, reptiles, and mammals - represent plausible and coherent mechanisms that explain these effects. Biological gradients are observed in several of the cited studies, although threshold doses and patterns vary among species. Given that the effects on the male gonads described in all of these experimental studies occurred only after atrazine exposure, temporality is also met here. Thus the case for atrazine as an endocrine disruptor that demasculinizes and feminizes male vertebrates meets all nine of the "Hill criteria".

  9. Summer cover crops reduce atrazine leaching to shallow groundwater in southern Florida.

    Science.gov (United States)

    Potter, Thomas L; Bosch, David D; Joo, Hyun; Schaffer, Bruce; Muñoz-Carpena, Rafael

    2007-01-01

    At Florida's southeastern tip, sweet corn (Zea Mays) is grown commercially during winter months. Most fields are treated with atrazine (6-chloro-N-ethyl-N'-[1-methylethyl]-1,3,5-triazine-2,4-diamine). Hydrogeologic conditions indicate a potential for shallow groundwater contamination. This was investigated by measuring the parent compound and three degradates--DEA (6-chloro-N-[1-methylethyl]-1,3,5-triazine-2,4-diamine), DIA (6-chloro-N-ethyl)-1,3,5-triazine-2,4-diamine, and HA (6-hydroxy-N-[1-methylethyl]-1,3,5-triazine-2,4-diamine)--in water samples collected beneath sweet corn plots treated annually with the herbicide. During the study, a potential mitigation measure (i.e., the use of a cover crop, Sunn Hemp [Crotalaria juncea L.], during summer fallow periods followed by chopping and turning the crop into soil before planting the next crop) was evaluated. Over 3.5 yr and production of four corn crops, groundwater monitoring indicated leaching of atrazine, DIA, and DEA, with DEA accounting for more than half of all residues in most samples. Predominance of DEA, which increased after the second atrazine application, was interpreted as an indication of rapid and extensive atrazine degradation in soil and indicated that an adapted community of atrazine degrading organisms had developed. A companion laboratory study found a sixfold increase in atrazine degradation rate in soil after three applications. Groundwater data also revealed that atrazine and degradates concentrations were significantly lower in samples collected beneath cover crop plots when compared with concentrations below fallow plots. Together, these findings demonstrated a relatively small although potentially significant risk for leaching of atrazine and its dealkylated degradates to groundwater and that the use of a cover crop like Sunn Hemp during summer months may be an effective mitigation measure.

  10. Effects of dissolved organic matter from sewage sludge on the atrazine sorption by soils

    Institute of Scientific and Technical Information of China (English)

    LING Wanting; XU Jianming; GAO Yanzheng

    2005-01-01

    The effects of dissolved organic matter (DOM), water soluble organic matter derived from sewage sludge, on the sorption of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-trazine) by soils were studied using a batch equilibrium technique. Six paddy soils, chosen so as to have different organic carbon contents, were experimented in this investigation. Atrazine sorption isotherms on soils were described by the linear equation, and the distribution coefficients without DOM (Kd) or with DOM (Kd*) were obtained. Generally, the values of Kd*/Kd initially insoil-solution system form. Critical concentrations of DOM (DOMnp) were obtained where the value of Kd* was equal to Kd. The presence of DOM with concentrations lower than DOMnp promoted atrazine sorption on soils (Kd* > Kd), whereas the presence of DOM with concentrations higher than DOMnp tended to inhibit atrazine sorption (Kd* < Kd). Interestingly, DOMnp for tested soils was negatively correlated to the soil organic carbon content, and the maximum of Kd*/Kd (i.e.Kmax) correlated positively with the maximum of DOM sorption on soil (Xmax). Further investigations showed that the presence of hydrophobic fraction of DOM evidently promoted the atrazine sorption on soils, whereas the presence of hydrophilic DOM fraction obviously tended to inhibit the atrazine sorption. Interactions of soil surfaces with DOM and its fractions were suggested to be the major processes determining atrazine sorption on soils. The results of this work provide a reference to the agricultural use of organic amendment such as sewage sludge for improving the availability of atrazine in soils.

  11. PC Basic Linear Algebra Subroutines

    Energy Technology Data Exchange (ETDEWEB)

    1992-03-09

    PC-BLAS is a highly optimized version of the Basic Linear Algebra Subprograms (BLAS), a standardized set of thirty-eight routines that perform low-level operations on vectors of numbers in single and double-precision real and complex arithmetic. Routines are included to find the index of the largest component of a vector, apply a Givens or modified Givens rotation, multiply a vector by a constant, determine the Euclidean length, perform a dot product, swap and copy vectors, and find the norm of a vector. The BLAS have been carefully written to minimize numerical problems such as loss of precision and underflow and are designed so that the computation is independent of the interface with the calling program. This independence is achieved through judicious use of Assembly language macros. Interfaces are provided for Lahey Fortran 77, Microsoft Fortran 77, and Ryan-McFarland IBM Professional Fortran.

  12. Examining the joint toxicity of chlorpyrifos and atrazine in the aquatic species: Lepomis macrochirus, Pimephales promelas and Chironomus tentans

    Energy Technology Data Exchange (ETDEWEB)

    Tyler Mehler, W.; Schuler, Lance J. [Fisheries and Illinois Aquaculture Center and Department of Zoology, Southern Illinois University at Carbondale, Carbondale, IL 62901-6511 (United States); Lydy, Michael J. [Fisheries and Illinois Aquaculture Center and Department of Zoology, Southern Illinois University at Carbondale, Carbondale, IL 62901-6511 (United States)], E-mail: mlydy@siu.edu

    2008-03-15

    The joint toxicity of chlorpyrifos and atrazine was compared to that of chlorpyrifos alone to discern any greater than additive response using both acute toxicity testing and whole-body residue analysis. In addition, acetylcholinesterase (AChE) inhibition and biotransformation were investigated to evaluate the toxic mode of action of chlorpyrifos in the presence of atrazine. The joint toxicity of atrazine and chlorpyrifos exhibited no significant difference in Lepomis macrochirus compared to chlorpyrifos alone; while studies performed with Pimephales promelas and Chironomus tentans, did show significant differences. AChE activity and biotransformation showed no significant differences between the joint toxicity of atrazine and chlorpyrifos and that of chlorpyrifos alone. From the data collected, the combination of atrazine and chlorpyrifos pose little additional risk than that of chlorpyrifos alone to the tested fish species. - The joint toxicity between atrazine and chlorpyrifos caused greater than additive responses in invertebrates, but the interactions in vertebrates was less pronounced.

  13. Gamma-ray induced degradation of diazinon and atrazine in natural groundwaters.

    Science.gov (United States)

    Mohamed, K A; Basfar, A A; Al-Shahrani, A A

    2009-07-30

    Degradation of diazinon and atrazine pesticides present in natural groundwaters was investigated on a laboratory scale upon gamma-irradiation from a (60)Co source. The effects of pesticide type, initial concentration, characteristics of natural groundwater, potential radical scavengers and absorbed dose on efficiency of pesticide degradation were investigated using GC-MS. gamma-Irradiation experiments were carried out for three concentrations (i.e. 0.329, 1.643 and 3.286 microM/diazinon and 0.464, 2.318 and 4.636 microM/atrazine) with irradiation doses over the range 0.5-5.6 kGy for diazinon and 0.2-21 kGy for atrazine. gamma-Radiolysis showed that diazinon was much easier to degrade by ionizing radiation compared to atrazine in all natural groundwater samples. This was observed at the three initial concentrations over the range irradiation doses. The irradiation doses required for degradation of 50 and 90% diazinon (distilled water) and atrazine (humic aqueous solution) at the three concentrations were not sufficient to degrade the same concentrations in different natural groundwater samples. Moreover, the presence of naturally occurring inorganic scavengers in solutions of diazinon and atrazine decreased significantly the efficiency of radiolytic degradation of pesticides, especially at higher concentrations.

  14. Ageing of atrazine in manure amended soils assessed by bioavailability to Pseudomonas sp. strain ADP.

    Science.gov (United States)

    Glæsner, Nadia; Bælum, Jacob; Strobel, Bjarne W; Jacobsen, Carsten S

    2014-04-01

    Animal manure is applied to agricultural land in areas of high livestock production. In the present study, we evaluated ageing of atrazine in two topsoils with and without addition of manure and in one subsoil. Ageing was assessed as the bioavailability of atrazine to the atrazine mineralizing bacteria Pseudomonas sp. strain ADP. Throughout an ageing period of 90 days bioavailability was investigated at days 1, 10, 32, 60 and 90, where ~10(8) cells g(-1) of the ADP strain was inoculated to the (14)C-atrazine exposed soil and (14)CO2 was collected over 7 days as a measure of mineralized atrazine. Even though the bioavailable residue decreased in all of the three soils as time proceeded, we found that ageing occurred faster in the topsoils rich in organic carbon than in subsoil. For one topsoil rich in organic carbon content, Simmelkær, we observed a higher degree of ageing when treated with manure. Contrarily, sorption experiments showed less sorption to Simmelkær treated with manure than the untreated soil indicating that sorption processes are not the only mechanisms of ageing. The other topsoil low in organic carbon content, Ringe, showed no significant difference in ageing between the manure-treated and untreated soil. The present study illustrates that not simply the organic carbon content influences adsorption and ageing of atrazine in soil but the origin and composition of organic matter plays an important role.

  15. Prenatal exposure to low doses of atrazine affects mating behaviors in male guppies.

    Science.gov (United States)

    Shenoy, Kausalya

    2014-07-01

    Performing appropriate mating behaviors is crucial to male reproductive success, especially in species where mating is predominantly via female mate choice. Mating behaviors are hormonally regulated and may be sexually selected traits: courtship displays are selected via mate choice, while forced copulations and aggressive behaviors are selected for via intrasexual competition. Endocrine disrupting compounds interfere with proper hormonal functioning in exposed animals. Exposures during developmentally crucial life stages can have irreversible effects lasting through adulthood. I tested the effects of prenatal exposure to environmentally relevant doses of a commonly used herbicide, atrazine (1 and 13.5μg/L) on mating behaviors in male guppies. Guppies were used as a model organism to test the effects of atrazine exposure on wildlife reproductive health. Adult female guppies were mated and exposed to the treatments throughout the gestation period, and offspring born to them were raised without further treatment. At adulthood, the males were tested for the effects of prenatal exposure on their mating behaviors such as courtship displays, gonopodium swings, forced copulatory attempts, and competitive and aggressive behaviors towards rivals who were not exposed to atrazine. I also tested female preference for treated males compared to control males. Atrazine-exposed males were less likely to perform the mating behaviors, and performed them less frequently, than control males. Atrazine exposure also made males less aggressive towards rivals. Females preferred untreated males over atrazine-treated males. In all cases, a non-monotonic pattern was seen, highlighting the significance of low-dose exposures.

  16. Atrazine affects phosphoprotein and protein expression in MCF-10A human breast epithelial cells.

    Science.gov (United States)

    Huang, Peixin; Yang, John; Song, Qisheng

    2014-10-01

    Atrazine, a member of the 2-chloro-s-triazine family of herbicides, is the most widely used pesticide in the world and often detected in agriculture watersheds. Although it was generally considered as an endocrine disruptor, posing a potential threat to human health, the molecular mechanisms of atrazine effects remain unclear. Using two-dimensional gel electrophoresis, we identified a panel of differentially expressed phosphoproteins and total proteins in human breast epithelial MCF-10A cells after being exposed to environmentally relevant concentrations of atrazine. Atrazine treatments for 6 h resulted in differential expression of 4 phosphoproteins and 8 total-proteins as compared to the control cells (>1.5-fold, patrazine treatment, ANP32A, was further analyzed for its expression, distribution and cellular localization using Western blot and immunocytochemical approaches. The results revealed that ANP32 expression after atrazine treatment increased dose and time dependently and was primarily located in the nucleus. This study may provide new evidence on the potential toxicity of atrazine in human cells.

  17. Effects of atrazine on growth and sex differentiation, in juveniles of the freshwater crayfish Cherax quadricarinatus.

    Science.gov (United States)

    Mac Loughlin, Camila; Canosa, Ivana S; Silveyra, Gabriela R; López Greco, Laura S; Rodríguez, Enrique M

    2016-09-01

    The effect of the herbicide atrazine was assayed in early juveniles of the redclaw crayfish Cherax quadricarinatus. Four cohorts of juveniles (a total of 280 animals) were exposed for 4 wk to each one of three atrazine concentrations (0.1, 0.5 and 2.5mg/L) or a control (0mg/L), from a commercial formulation having 90% of active principle. At the end of the exposure, no significant (p>0.05) differences in either mortality or molting were noted. However, the weight gain and the protein content of abdominal muscle decreased significantly (p<0.05) in the highest atrazine concentration as compared to control, indicating that atrazine acted as a relevant stressor, although at a concentration higher than those reported in the environment. Besides, the proportion of females increased progressively as the atrazine concentration increases, being significantly (p<0.05) higher than that of controls at the highest concentration assayed. Both macroscopic and histological analysis revealed a normal architecture of gonopores and gonads in both control and exposed animals. The obtained results strongly suggest that atrazine could be causing an endocrine disruption on the hormonal system responsible for the sexual differentiation of the studied species, increasing the proportion of female proportion without disturbing the gonad structure.

  18. Microwave assisted rapid and complete degradation of atrazine using TiO(2) nanotube photocatalyst suspensions.

    Science.gov (United States)

    Zhanqi, Gao; Shaogui, Yang; Na, Ta; Cheng, Sun

    2007-07-16

    A technology, microwave-assisted photocatalysis on TiO(2) nanotubes, which can be applied to degrade atrazine rapidly and completely, was investigated. TiO(2) nanotubes were prepared, and confirmed by XRD, TEM and ESR. Microwave-assisted photocatalytic degradation of atrazine in aqueous solution was investigated. The result indicates that atrazine is completely degraded in 5min and the mineralization efficiency is 98.5% in 20min, which is obviously more efficient than that by the traditional photocatalytic degradation methods. It may be attributed to the intense UV radiation generated by electrodeless discharge lamps under microwave irradiation, the increased number of OH, additional defect sites on TiO(2) under the irradiation of microwave and larger specific surface area of TiO(2) nanotubes which could adsorb more organic substances to degrade than TiO(2) nanoparticles. Along with the degradation of atrazine, the concentrations of Cl(-) and NO(3)(-) increase gradually. In 20min [Cl(-)] and [NO(3)(-)] are 3, 27.8mg/L, respectively, which are close to their stoichiometric values. The major intermediates of atrazine were identified by HPLC/MS and possible degradation pathways of atrazine in microwave-assisted photocatalysis on TiO(2) nanotubes were proposed.

  19. Environmental behavior and toxicity of herbicides atrazine and simazine

    Directory of Open Access Journals (Sweden)

    Ana Paula Barbosa do Carmo

    2013-04-01

    Full Text Available This article shows some environmental and toxicology aspects of triazine herbicides atrazine and simazine. These compounds are used to control weeds in sugar and corn crops. Despite being partially soluble, they can be detected in ground and surface water. Their mobility and biodegradation in the soil-water system can vary depending on the intrinsic characteristics of each matrice, such as organic matter content. Although considered slightly toxic, these herbicides have a strong ability to interfere in the nervous and endocrine systems of human and wild biota. The detoxification mechanisms are similar to other xenobiotics; however, little is known about the effects on human health caused by simazine. Therefore, the use of these compounds should be revised due to their environmental behavior and toxicological effects.

  20. Rotordynamics on the PC: Further Capabilities of ARDS

    Science.gov (United States)

    Fleming, David P.

    1997-01-01

    Rotordynamics codes for personal computers are now becoming available. One of the most capable codes is Analysis of RotorDynamic Systems (ARDS) which uses the component mode synthesis method to analyze a system of up to 5 rotating shafts. ARDS was originally written for a mainframe computer but has been successfully ported to a PC; its basic capabilities for steady-state and transient analysis were reported in an earlier paper. Additional functions have now been added to the PC version of ARDS. These functions include: 1) Estimation of the peak response following blade loss without resorting to a full transient analysis; 2) Calculation of response sensitivity to input parameters; 3) Formulation of optimum rotor and damper designs to place critical speeds in desirable ranges or minimize bearing loads; 4) Production of Poincard plots so the presence of chaotic motion can be ascertained. ARDS produces printed and plotted output. The executable code uses the full array sizes of the mainframe version and fits on a high density floppy disc. Examples of all program capabilities are presented and discussed.

  1. Control Effect of 80%Nicosulfuron·Atrazine Water-dispersible Granules on Weeds in Spring Maize Field

    Institute of Scientific and Technical Information of China (English)

    Yueqi SHEN; Rende Ql

    2014-01-01

    This study aimed to investigate the control effect of different concentrations of 80% nicosulfuron·atrazine water-dispersible granules on weeds in spring maize field. [Method] Maize field was sprayed with 300, 375, 450, 750 g/hm2 80% nicosulfuron·atrazine water-dispersible granules respectively, with 40 g/L nico-sulfuron suspending concentrate and 38% atrazine suspending concentrate as con-trol agents. Artificial weeding and control (CK) plots were set. [Result] Fresh weight control efficiency of 375-750 g/hm2 80% nicosulfuron ·atrazine water-dispersible granules was significantly higher than that of 40 g/L nicosulfuron suspending con-centrate and 38% atrazine suspending concentrate; no obvious phytotoxicity symp-toms were observed after application of 300-450 g/hm2 80% nicosulfuron·atrazine water-dispersible granules; 750 g/hm2 80% nicosulfuron·atrazine water-dispersible granules posed certain impact on the growth of maize seedlings. Compared with control plots, various doses of 80% nicosulfuron·atrazine water-dispersible granules signifi-cantly improved the yield of maize. [Conclusion] ln the present study, 375-450 g/hm2 80% nicosulfuron·atrazine water-dispersible granules exhibited high control effect on weeds in maize field and were safe for the growth of maize seedlings.

  2. Atrazine Triggers DNA Damage Response and Induces DNA Double-Strand Breaks in MCF-10A Cells.

    Science.gov (United States)

    Huang, Peixin; Yang, John; Ning, Jie; Wang, Michael; Song, Qisheng

    2015-06-24

    Atrazine, a pre-emergent herbicide in the chloro-s-triazine family, has been widely used in crop lands and often detected in agriculture watersheds, which is considered as a potential threat to human health. Although atrazine and its metabolites showed an elevated incidence of mammary tumors in female Sprague-Dawley (SD) rats, no molecular evidence was found relevant to its carcinogenesis in humans. This study aims to determine whether atrazine could induce the expression of DNA damage response-related proteins in normal human breast epithelial cells (MCF-10A) and to examine the cytotoxicity of atrazine at a molecular level. Our results indicate that a short-term exposure of MCF-10A to an environmentally-detectable concentration of atrazine (0.1 µg/mL) significantly increased the expression of tumor necrosis factor receptor-1 (TNFR1) and phosphorylated Rad17 in the cells. Atrazine treatment increased H2AX phosphorylation (γH2AX) and the formation of γH2AX foci in the nuclei of MCF-10A cells. Atrazine also sequentially elevated DNA damage checkpoint proteins of ATM- and RAD3-related (ATR), ATRIP and phospho-Chk1, suggesting that atrazine could induce DNA double-strand breaks and trigger the DNA damage response ATR-Chk1 pathway in MCF-10A cells. Further investigations are needed to determine whether atrazine-triggered DNA double-strand breaks and DNA damage response ATR-Chk1 pathway occur in vivo.

  3. Response to variable light intensity in photoacclimated algae and cyanobacteria exposed to atrazine

    Energy Technology Data Exchange (ETDEWEB)

    Deblois, Charles P.; Dufresne, Karine [Department of Biological Sciences-TOXEN, Ecotoxicology of Aquatic Microorganisms Laboratory, Universite du Quebec a Montreal, Succ. Centre-Ville, Montreal, Quebec (Canada); Juneau, Philippe, E-mail: juneau.philippe@uqam.ca [Department of Biological Sciences-TOXEN, Ecotoxicology of Aquatic Microorganisms Laboratory, Universite du Quebec a Montreal, Succ. Centre-Ville, Montreal, Quebec (Canada)

    2013-01-15

    Atrazine is frequently detected in freshwater ecosystems exposed to agricultural waste waters and runoffs worldwide and it can affect non-target organisms (mainly photoautotrophic) and modify community structure. Meanwhile, light environment is known to vary between aquatic ecosystems, but also before and during the exposure to atrazine and these variations may modify the sensitivity to atrazine of photoautotroph organisms. In this study, 10 species of phytoplankton (chlorophytes, baccilariophytes and cyanophytes) acclimated to low or high light intensities were exposed to atrazine and light of different intensities to compare their combined effect. Our data showed that chlorophytes and baccilariophytes were more resistant to atrazine compared to cyanophytes for all light conditions. Atrazine was found to inhibit {Phi}{sup Prime }{sub M}, {Psi}{sub 0}, P{sub M} and non-photochemical quenching for all species indicating an effect on electron transport, primary production and photoregulation processes. These data also indicate a higher sensitivity of {Psi}{sub 0} (average {Psi}{sub 0}-EC{sub 50} of 91 {+-} 11 nM or 19.6 {+-} 0.9 {mu}g L{sup -1}) compared to {Phi}{sup Prime }{sub M} (average {Phi}{sup Prime }{sub M}-EC{sub 50} of 217 {+-} 19 nM or 46.8 {+-} 4.1 {mu}g L{sup -1}) and suggest that photoregulation processes activated in presence of light decrease the effect of atrazine. We also showed that increasing light intensity decreased {Phi}{sup Prime }{sub M}-EC{sub 50} in both low (except baccilariophytes) and high light acclimated conditions. Despite this similarity, most species acclimated to high light were found to have higher or similar {Phi}{sup Prime }{sub M}-EC{sub 50} compared to low light acclimated cells and thus, were less sensitive to atrazine in low light and high light environments. We concluded that an increase in the plastoquinone pool induced by acclimation to high light decreased the sensitivity to atrazine in phytoplankton and we hypothesized

  4. PC Cluster Machine Equipped with High-Speed Communication Software

    CERN Document Server

    Tanaka, M

    2004-01-01

    A high performance Beowulf (PC cluster) machine installed with Linux operating system and MPI (Message Passing Interface) for interprocessor communications has been constructed using Gigabit Ethernet and the communication software GAMMA (Genoa Active Message Machine), instead of the standard TCP/IP protocol. Fast C/Fortran compilers have been exploited with the GAMMA communication libraries. This method has eliminated large communication overhead of TCP/IP and resulted in significant increase in the computational performance of real application programs including the first-principle molecular dynamics simulation code. (Keywords: non TCP/IP, active messages, small latency, fast C/Fortran compilers, materials science, first-principle molecular dynamics)

  5. Green PC Saves Human Life

    Directory of Open Access Journals (Sweden)

    Abdulla Shaik

    2012-03-01

    Full Text Available Green computing is the study and practice of using computing resources efficiently. This give idea about reduce the use of hazardous materials maximize energy efficiency during the product's lifetime, and promote recyclability. Green computing can be broadly defined as the problem of reducing the overall carbon footprint of computing and communication infrastructure, such as data centers, by using energy-efficient design and operations. As the environmentalists and energy conservationists ponder over the issue of conserving environment, technologists have come out with a simple solution to let you contribute to the “Go Green” campaign- with the help of Green PCs. By using green computing practices; you can improve energy management, increase energy efficiency, reduce e-waste, and save money. Taking into consideration the popular use of information technology industry, it has to lead a revolution of sorts by turning green in a manner no industry has ever done before. It is worth emphasizing that this “green technology” should not be just about sound bytes to impress activists but concrete action and organizational policy. The plan towards Green PC should include new electronic products and services with optimum efficiency and all possible options towards energy savings and technical issues in high-performance green computing span the spectrum from green infrastructure like energy-efficient buildings, intelligent cooling systems, green power sources for green hardware multi-core computing systems, energy-efficient server design, energy-efficient solid-state storage for green software and applications.

  6. Effects of Prenatal Exposure to a Low Dose Atrazine Metabolite Mixture on pubertal timing and prostrate Development of Male Long Evans Rats.

    Science.gov (United States)

    The present study examines the postnatal reproductive development of male rats following prenatal exposure to an atrazine metabolite mixture (AMM) consisting of the herbicide atrazine and its environmental metabolites diaminochlorotriazine, hydroxyatrazine, deethylatrazine, and d...

  7. PC-based tele-audiometry.

    Science.gov (United States)

    Choi, Jong Min; Lee, Haet Bit; Park, Cheol Soo; Oh, Seung Ha; Park, Kwang Suk

    2007-10-01

    A personal computer (PC)-based audiometer was developed for interactive remote audiometry. This paper describes a tele-audiometric system and evaluates the performance of the device when compared with conventional face-to-face audiometry. The tele-audiometric system is fully PC-based. A sound card featuring a high-quality digital-to-analog converter is used as a pure-tone generator. The audiometric programs were developed based on Microsoft Windows in order to maximize usability. Audiologists and their subjects can use the tele-audiometry system as one would utilize any PC application. A calibration procedure has been applied for the standardization of sound levels in the remote system. The performance of this system was evaluated by comparing PC-based audiometry with the conventional clinical audiometry system for 37 subjects. Also, performance of the PC-based system was evaluated during use at a remote site. The PC-based audiometry system estimated the audiometric threshold with an error of less than 2.3 dBSPL. Only 10.7% of the results exhibited an error greater than 5 dBSPL during use at a remote site. The PC-based tele-audiomerty showed acceptable results for use at a remote site. This PC-based system can be used effectively and easily in many locations that have Internet access but no local audiologists.

  8. Hydrogen bonds in PC61BM solids

    Science.gov (United States)

    Sheng, Chun-Qi; Li, Wen-Jie; Du, Ying-Ying; Chen, Guang-Hua; Chen, Zheng; Li, Hai-Yang; Li, Hong-Nian

    2015-09-01

    We have studied the hydrogen bonds in PC61BM solids. Inter-molecular interaction is analyzed theoretically for the well-defined monoclinic (P21/n) structure. The results indicate that PC61BM combines into C-H⋯Od bonded molecular chains, where Od denotes the doubly-bonded O atom of PC61BM. The molecular chains are linked together by C-H⋯Os bonds, where Os denotes the singly-bonded O atom of PC61BM. To reveal the consequences of hydrogen bond formation on the structural properties of PC61BM solids (not limited to the monoclinic structure), we design and perform some experiments for annealed samples with the monoclinic (P21/n) PC61BM as starting material. The experiments include differential scanning calorimetry, X-ray diffraction and infrared absorption measurements. Structural phase transitions are observed below the melting point. The C-H⋯Od bonds seem persisting in the altered structures. The inter-molecular hydrogen bonds can help to understand the phase separation in polymer/PC61BM blends and may be responsible for the existence of liquid PC61BM.

  9. Degradation of atrazine by Frankia alni ACN14a: gene regulation, dealkylation, and dechlorination.

    Science.gov (United States)

    Rehan, Medhat; Kluge, Martin; Fränzle, Stefan; Kellner, Harald; Ullrich, René; Hofrichter, Martin

    2014-07-01

    Atrazine is transformed to N-isopropylammelide through hydroxyatrazine as an intermediate as indicated by high-performance liquid chromatography/mass spectroscopy in culture filtrates of Frankia alni ACN14a and Frankia sp. EuI1c. Both Frankia strains have the ability to degrade atrazine via dechlorination and dealkylation and, subsequently, may be using it as a nitrogen and carbon source as detected here by increasing their growth patterns. Bioinformatic analysis of the Frankia genomes revealed that a potential gene cluster involved in atrazine decomposition contains three genes, namely, trzN (FRAAL1474 and FraEuI1c_5874), atzB (FRAAL1473 and FraEuI1c_5875), and atzR (FRAAL1471). The relative messenger RNA gene expression of the former genes was examined by qRT-PCR. The LysR-type transcriptional regulator atzR (FRAAL1471), which is expected to control the cluster expression, showed a 13-fold increase in the expression level under atrazine stress. Moreover, the putative adenosine aminohydrolase 3 atzB (FRAAL1473), which is expected to dealkylate the N-ethyl group of atrazine, showed also an increased expression by factor 16 with increased exposure. Eventually, the trzN (FRAAL1474) gene, which is predicted to encode a putative amidohydrolase catalyzing atrazine dechlorination, exhibited 31-fold increased expression. To our best knowledge, this is the first report about adenosine aminohydrolase 3 function in the dealkylation of the N-ethyl group from atrazine.

  10. Variability in carbon and nitrogen isotope fractionation associated with bacterial hydrolysis of atrazine

    Science.gov (United States)

    Meyer, A.; Penning, H.; Elsner, M.

    2009-04-01

    Even after legislative prohibition in 1991 by the European Union, the pesticide atrazine and its metabolites are still detected in surface and ground water frequently exceeding the permitted drinking water concentration limit of 0,1 g/L. Despite much recent research on atrazine, its risk assessment in the environment is still a major challenge because of the difficulty of establishing mass balances in the subsurface. To obtain a better insight into the fate of atrazine, we developed compound-specific stable isotope analysis (CSIA) for atrazine. CSIA has proven valuable for assessing organic contaminants in subsurface environments, on the one hand for source identification and on the other hand to trace (bio)chemical degradation reactions through isotope fractionation in the compounds. Such assessment is based on the Rayleigh equation and therein on the isotope enrichment factor ɛ, which must be determined experimentally beforehand. In ongoing work, we therefore measured carbon and nitrogen isotope fractionation associated with biotic hydrolsis of atrazine. C and N isotope enrichment factors were determined in resting cell experiments for Pseudomonas sp. ADP, Chelatobacter heintzii and Arthrobacter aurescens TC1, strains that hydrolyse atrazine in the initial transformation reaction. Carbon and nitrogen isotope enrichment factors were distinctly different between the bacterial strains. However, when plotting shifts in carbon isotope ratios versus shifts in nitrogen isotope ratios the slopes of the different degradation experiments coincided well. These results give evidence that all bacterial strains were carrying out the same initial biochemical degradation reaction, but that the associated isotope fractionation, as represented by the enrichment factors, was masked to a different extent owing to different rate determining steps prior to the isotopically sensitive bond cleavage (commitment to catalysis). Our study therefore illustrates the benefit of multi

  11. Monitoring of atrazine and its metabolites in groundwaters of the Republic of Serbia

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    Lazić Sanja D.

    2013-01-01

    Full Text Available The intensive use of atrazine herbicides in the Republic of Serbia during recent decades has led to the accumulation of residues of atrazine and its metabolites in the environment, which endangers groundwater. With the objective to check the presence of atrazine and its metabolites deethylatrazine (DEA and deisopropylatrazine (DIA in the groundwater, the monitoring programme was carried out over the period from 2007 to 2009 in the localities where the atrazine-based herbicides were intensively applied for a number of years. Samples were taken from 327 localities, in total there were 1408 samples of groundwater of the first welling-up collected. The atrazine and its metabolites were extracted with methanol by means of ENVI-C18 (47mm disc, and the residue level of the studied compounds was analyzed with gas chromatography-mass spectrometry (GC-MS. In the most of groundwater samples collected from agricultural regions, average value of all tested analytes was above 0.1 μg/dm3. The highest values of atrazine and its metabolites were in the localities that is known for intensive maize production and in the areas of this region under orchards and vineyards, where atrazine was used in large quantities. The average values of content of this active substance in analyzed samples are the result of intensive and long-term usage of this group of herbicides, as well as the high level of groundwater in this region. [Acknowledgements. Ministarstvo poljoprivrede, šumarstva i vodoprivrede i Ministarstvo prosvete i nauke Republike Srbije (projekat III43005

  12. Preparation and characterization of a lipoid adsorption material and its atrazine removal performance

    Institute of Scientific and Technical Information of China (English)

    Zhiqiang Chen; Qinxue Wen; Jiaxiang Lian; Nanqi Ren

    2011-01-01

    A novel adsorbent named lipoid adsorption material (LAM),with a hydrophobic nucleolus (triolein) and a hydrophilic membrane structure (polyamide),was synthesized to remove hydrophobic organic chemicals (HOCs) from solution.Triolein,a type of lipoid,was entrapped by the polyamide membrane through an interfacial polymerization reaction.The method of preparation and the structure of the LAM were investigated and subsequent experiments were conducted to determine the characteristics of atrazine (a type of HOC) removal from wastewater using LAM as the adsorbent.The results showed that LAM had a regular structure compared with the prepolymer,where compact particles were linked with each other and openings were present in the structure of the LAM in which the fat drops formed from triolein were entrapped.In contrast to the atrazine adsorption behavior of powdered activated carbon (PAC),LAM showed a persistent adsorption capacity for atrazine when initial concentrations of 0.57,1.12,8.31 and 19.01 mg/L were present,and the equilibrium time was 12 hr.Using an 8 mg/L initial concentration of atrazine as an indicator of HOCs in aqueous solution,experiments on the adsorption capacity of the LAM showed 69.3% removal within 6-12 hr contact time,which was close to the 75.5%removal of atrazine by PAC.Results indicated that LAM has two atrazine removal mechanisms,namely the bioaccumulation of atrazine by the nucleous material and physical adsorption to the LAM membrane.Bioaccumulation was the main removal mechanism.

  13. Atrazine-Mediated Oxidative Stress Responses and Lipid Peroxidation in the Tissues of Clarias gariepinus

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    Olufemi David Owolabi

    2017-02-01

    Full Text Available Background: Fish have been at high risk of atrazine toxicity. Comparative atrazine toxicity on the tissues of Clarias gariepinus is scanty. Therefore, acute and chronic effects of atrazine on some biochemical parameters in Clarias gariepinus were investigated in this study. Methods: Atrazine toxicity was determined by assessing the responses of glucose, protein, alanine aminotransferase (ALT, aspartate aminotransferase (AST, lactate dehydrogenase (LDH, superoxide dismutase (SOD, acetylcholinestarase (AChE and malondialdehyde (MDA in blood, gill and liver of fish exposed to both acute (0.00, 28.00, 30.00, 32.00 and 34.00 µg/l and chronic (0.00, 7.00, 7.50, 8.00 and 8.50 µg/l concentrations for 96 h and 28 d, respectively. Results: In acute exposure, glucose and MDA levels showed significant (P<0.05 variations in all tissues. Protein and LDH decreased in all tissues except the latter slightly increased at 32.00µg/l in blood and liver compared to control. ALT and AChE were induced in blood but inhibited in gill and liver. SOD significantly decreased in blood but increased in gill and liver. AST was activated in blood and liver but reduced in gill. In chronic exposure, glucose, protein, SOD and AChE were inhibited in all tissues, while MDA level was induced. ALT, AST, and LDH activities were induced in blood but inhibited in gill and liver except 22.90% induction noted in liver at 8.00 µg/l atrazine. Conclusion: Exposure to varying concentrations of atrazine induced enzymatic/metabolic alterations in C. gariepinus. These alterations can be used as biomarkers of atrazine toxicity in fish.

  14. Biodegradation of atrazine by Rhodococcus sp. BCH2 to N-isopropylammelide with subsequent assessment of toxicity of biodegraded metabolites.

    Science.gov (United States)

    Kolekar, Parag D; Phugare, Swapnil S; Jadhav, Jyoti P

    2014-02-01

    Atrazine is a persistent organic pollutant in the environment which affects not only terrestrial and aquatic biota but also human health. Since its removal from the environment is needed, atrazine biodegradation is achieved in the present study using the bacterium Rhodococcus sp. BCH2 isolated from soil, long-term treated with atrazine. The bacterium was capable of degrading about 75 % atrazine in liquid medium having pH 7 under aerobic and dark condition within 7 days. The degradation ability of the bacterium at various temperatures (20-60 °C), pH (range 3-11), carbon (glucose, fructose, sucrose, starch, lactose, and maltose), and nitrogen (ammonium molybdate, sodium nitrate, potassium nitrate, and urea) sources were studied for triumph optimum atrazine degradation. The results indicate that atrazine degradation at higher concentrations (100 ppm) was pH and temperature dependent. However, glucose and potassium nitrate were optimum carbon and nitrogen source, respectively. Atrazine biodegradation analysis was carried out by using high-performance thin-layer chromatography (HPTLC), Fourier transform infrared spectroscopy (FTIR), and liquid chromatography quadrupole time-of-flight (LC/Q-TOF-MS) techniques. LC/Q-TOF-MS analysis revealed formation of various intermediate metabolites including hydroxyatrazine, N-isopropylammelide, deisopropylhydroxyatrazine, deethylatrazine, deisopropylatrazine, and deisopropyldeethylatrazine which was helpful to propose biochemical degradation pathway of atrazine. Furthermore, the toxicological studies of atrazine and its biodegraded metabolites were executed on earthworm Eisenia foetida as a model organism with respect to enzymatic (SOD and Catalase) antioxidant defense mechanism and lipid peroxidation studies. These results suggest innocuous degradation of atrazine by Rhodococcus sp. BCH2 in nontoxic form. Therefore the Rhodococcus sp.BCH2 could prove a valuable source for the eco-friendly biodegradation of atrazine pesticide.

  15. Coding Partitions

    Directory of Open Access Journals (Sweden)

    Fabio Burderi

    2007-05-01

    Full Text Available Motivated by the study of decipherability conditions for codes weaker than Unique Decipherability (UD, we introduce the notion of coding partition. Such a notion generalizes that of UD code and, for codes that are not UD, allows to recover the ``unique decipherability" at the level of the classes of the partition. By tacking into account the natural order between the partitions, we define the characteristic partition of a code X as the finest coding partition of X. This leads to introduce the canonical decomposition of a code in at most one unambiguouscomponent and other (if any totally ambiguouscomponents. In the case the code is finite, we give an algorithm for computing its canonical partition. This, in particular, allows to decide whether a given partition of a finite code X is a coding partition. This last problem is then approached in the case the code is a rational set. We prove its decidability under the hypothesis that the partition contains a finite number of classes and each class is a rational set. Moreover we conjecture that the canonical partition satisfies such a hypothesis. Finally we consider also some relationships between coding partitions and varieties of codes.

  16. Degradation and sorption of fipronil and atrazine in Latossols with organic residues from sugarcane crop

    Directory of Open Access Journals (Sweden)

    Raquel de Oliveira Silva

    2016-07-01

    Full Text Available ABSTRACT: Organic residues from sugarcane crop and processing (vinasse, boiler ash, cake filter, and straw are commonly applied or left on the soil to enhance its fertility. However, they can influence pesticide degradation and sorption. The objective of this study was to assess the effect of adding these organic residues on the degradation and sorption of fipronil and atrazine in two soils of the State of Mato Grosso do Sul, MS, Brazil. The degradation experiment was carried out with laboratory-incubated (40 days; 28°C; 70% field capacity soils (0-10cm. The batch equilibration method was used to determine sorption. Fipronil (half-life values of 15-105 days showed to be more persistent than atrazine (7-17 days. Vinasse application to the soil favored fipronil and atrazine degradation, whereas cake filter application decreased the degradation rates for both pesticides. Values for sorption coefficients (Kd were determined for fipronil (5.1-13.2mL g-1 and atrazine (0.5-1.5mL g-1. Only straw and cake filter residues enhanced fipronil sorption when added to the soil, whereas all sugarcane residues increased atrazine sorption.

  17. Effect of fluctuating soil humidity on in situ bioavailability and degradation of atrazine.

    Science.gov (United States)

    Ngigi, Anastasiah; Dörfler, Ulrike; Scherb, Hagen; Getenga, Zachary; Boga, Hamadi; Schroll, Reiner

    2011-07-01

    This study elucidates the effect of fluctuating soil moisture on the co-metabolic degradation of atrazine (6-chloro-N(2)-ethyl-N(4)-isopropyl-1,3,5-triazine-2,4-diamine) in soil. Degradation experiments with (14)C-ring-labelled atrazine were carried out at (i) constant (CH) and (ii) fluctuating soil humidity (FH). Temperature was kept constant in all experiments. Experiments under constant soil moisture conditions were conducted at a water potential of -15 kPa and the sets which were run under fluctuating soil moisture conditions were subjected to eight drying-rewetting cycles where they were dried to a water potential of around -200 kPa and rewetted to -15 kPa. Mineralization was monitored continuously over a period of 56d. Every two weeks the pesticide residues in soil pore water (PW), the methanol-extractable pesticide residues, the non-extractable residues (NER), and the total cell counts were determined. In the soil with FH conditions, mineralization of atrazine as well as the formation of the intermediate product deisopropyl-2-hydroxyatrazine was increased compared to the soil with constant humidity. In general, we found a significant correlation between the formation of this metabolite and atrazine mineralization. The cell counts were not different in the two experimental variants. These results indicate that the microbial activity was not a limiting factor but the mineralization of atrazine was essentially controlled by the bioavailability of the parent compound and the degradation product deisopropyl-2-hydroxyatrazine.

  18. [Degradation of endocrine disruptor atrazine in drinking water by UV radiation].

    Science.gov (United States)

    Wang, Li; Gao, Nai-yun; Wei, Hong-bin; Xia, Li-hua; Cui, Jing

    2006-06-01

    The degradation of atrazine with low concentration in drinking water by UV radiation was studied. The main influencing factors and degradation mechanism of this technology were discussed. Experimental results show that the photolytic degradation of atrazine by UV radiation alone is very efficient. Under 205 microW/cm2 irradiation intensity, atrazine removal ratio is 92.38% after 120 minutes. The rate of photodecomposition in aqueous solution follows first-order kinetics. The removal ratio of atrazine can be greatly enhanced by increasing the intensity of UV radiation. The initial concentration of atrazine has no effect on the oxidation reaction. The organic matter and various ion in tap water will decrease the degradation rate. The primary degradation pathway is dechlorination. The reaction rate is high. The hydroxylated compound is the major intermediate product. Hydroyatrazine can be further decomposed by UV radiation and form dealkylated derivatives. But the rate of dealkylated reaction is very low. There is intimate relationship between the change of pH in the solution and the formation of intermediate products.

  19. Distribution of atrazine in a crop-soil-groundwater system at Baiyangdian Lake area in China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper, the concentration distribution and environmentalfate of atrazine in a crop-soil-groundwater system at Baiyangdian Lake area of North China were studied. The concentration of the herbicide in spatial and vertical soils, and in roots, stem, leaf, corncob and kernel of corn, and in groundwater were measured by HPLC. The results showed that the variation of spatial concentration of atrazine in soil can be described by first-order kinetics equation which has a half-life of 360 days and a rate constant of 0.0019d-1. The vertical variation of atrazine concentration with soil depth follows the exponential decay law. After 120 days following atrazine application, the mass distributions of this herbicide in crop-soil-groundwater system are 71% in soil, 20% in groundwater and 1% in crop respectively, and 8% due to loss by degradation or often removal processes. The order of atrazine concentration in every part of corn crop is in roots>in corncob>in kernel of corn>in leaf.

  20. Combined bioremediation of atrazine-contaminated soil by Pennisetum and Arthrobacter sp. strain DNS10.

    Science.gov (United States)

    Zhang, Ying; Ge, Shijie; Jiang, Mingyue; Jiang, Zhao; Wang, Zhigang; Ma, Bingbing

    2014-05-01

    Strain DNS10 was isolated from the black soil collected from the northeast of China which had been cultivated with atrazine as the sole nitrogen source. Pennisetum is a common plant in Heilongjiang Province of China. The main objective of this paper was to evaluate the efficiency of plant-microbe joint interactions (Arthrobacter sp. DNS10 + Pennisetum) in atrazine degradation compared with single-strain and single-plant effects. Plant-microbe joint interactions degraded 98.10 % of the atrazine, while single strain and single plant only degraded 87.38 and 66.71 % after a 30-day experimental period, respectively. The results indicated that plant-microbe joint interactions had a better degradation effect. Meanwhile, we found that plant-microbe joint interactions showed a higher microbial diversity. The results of microbial diversity illustrated that the positive effects of cropping could improve soil microbial growth and activity. In addition, we planted atrazine-sensitive plants (soybean) in the soil after repair. The results showed that soybean growth in soil previously treated with the plant-microbe joint interactions treatment was better compared with other treatments after 20 days of growth. This was further proved that the soil is more conducive for crop cultivation. Hence, plant-microbe joint interactions are considered to be a potential tool in the remediation of atrazine-contaminated soil.

  1. Effects of atrazine on endocrinology and physiology in juvenile barramundi, Lates calcarifer (Bloch).

    Science.gov (United States)

    Kroon, Frederieke J; Hook, Sharon E; Jones, Dean; Metcalfe, Suzanne; Osborn, Hannah L

    2014-07-01

    Exposure to certain environmental contaminants such as agricultural pesticides can alter normal endocrine and reproductive parameters in wild fish populations. Recent studies have found widespread pesticide contamination across the rivers that discharge into the Great Barrier Reef lagoon. Potential impacts on native fish species exposed to known endocrine disrupting chemicals such as atrazine, simazine, and diuron have not been assessed. In the present study, the authors examined the endocrine and physiological effects of short-term, acute exposure of environmentally relevant concentrations of analytical grade atrazine in juvenile barramundi (Lates calcarifer) in a controlled laboratory experiment. Expression of hepatic vitellogenin was not affected, supporting results of previous studies that showed that atrazine does not have a direct estrogenic effect via mediation of estrogen receptors. The lack of effect on brain cytochrome P19B (CYP19B) expression levels, combined with increases in testosterone (T) and 17β estradiol and a stable T:17β estradiol ratio, does not support the hypothesis that atrazine has an indirect estrogenic effect via modulation of aromatase expression. Gill ventilation rate, a measure of oxidative stress, did not change in contrast to other studies finding enhanced osmoregulatory disturbance and gill histopathology after atrazine exposure. To more closely reflect field conditions, the authors recommend that laboratory studies should focus more on examining the effects of commercial pesticide formulations that contain additional ingredients that have been found to be disruptive to endocrine function.

  2. Atrazine-induced changes in the myocardial structure of peripubertal rats.

    Science.gov (United States)

    Rajkovic, Vesna; Kovac, Renata; Koledin, Ivana; Matavulj, Milica

    2014-04-01

    The aim of the present study was to investigate the effect of atrazine (6-chloro-N(2)-ethyl-N(4)-isopropyl-1,3,5-triazine-2,4-diamine) on the left ventricle myocardium in juvenile/peripubertal male Wistar rats. Atrazine was administered orally at 50 or 200 mg/kg of body weight dose for 28 consecutive days. In order to assess possible structural alterations, tissue sections were examined histologically and then subjected to quantification analysis using stereological methods. The tissue specimens were routinely processed and stained with Mallory trichrome method in order to clearly distinguish muscle cells from the connective tissue components. A toluidine blue staining method was additionally used for the demonstration of mast cells. Statistically significant increase in length density and numerical density of capillaries were found at both the investigated doses of atrazine compared with the control. The increase in surface density and volume density of capillaries found at lower dosage of atrazine was significant in comparison with the control. The extensive mast cell degranulation was noted on the histological examination at both doses of the applied chemical. No significant changes were demonstrated for the stereological parameters of cardiomyocytes. Based on the available published data and the present results, it can be concluded that atrazine promoted angiogenesis in the rat myocardium, which might be partially mediated by mast cells.

  3. Oxidative stress response induced by atrazine in Palaemonetes argentinus: the protective effect of vitamin E.

    Science.gov (United States)

    Griboff, Julieta; Morales, David; Bertrand, Lidwina; Bonansea, Rocío Inés; Monferrán, Magdalena Victoria; Asis, Ramón; Wunderlin, Daniel Alberto; Amé, María Valeria

    2014-10-01

    The widespread contamination and persistence of the herbicide atrazine residues in the environment resulted in the exposure of non-target organisms. The present study was undertaken to investigate the effect of atrazine in the response of oxidative stress biomarkers in the freshwater shrimp Palaemonetes argentinus and the protective effect of vitamin-E against atrazine-induced toxicity. Therefore, two batches of P. argentinus were fed for 21 days with a commercial food enriched in proteins (D1) or with D2, composed of D1 enriched with vitamin-E (6.8 and 16.0mg% of vitamin-E, respectively). Subsequently, half of the individuals of each group were exposed to atrazine (0.4mgL(-1)) for 24h and the others remained as controls. Atrazine promoted oxidative stress response in P. argentinus fed with D1 as indicated by enhanced H2O2 content and induction of superoxide dismutase, glutathione-S-transferases and glutathione reductase. This antioxidant activity would prevent the increment of thiobarbituric acid reactive substances in the shrimp tissues. P. argentinus fed with D2 reversed the response of the biomarkers measured. However, the activation of antioxidants response had an energetic cost, which was revealed by a decrease in lipids storage in shrimps. These results show the modulatory effect of vit-E on oxidative stress and its potential use as an effective antioxidant to be applied in chemoprotection strategies during aquaculture.

  4. Atrazine molecular imprinted polymers: comparative analysis by far-infrared and ultraviolet induced polymerization.

    Science.gov (United States)

    Chen, Jun; Bai, Lian-Yang; Liu, Kun-Feng; Liu, Run-Qiang; Zhang, Yu-Ping

    2014-01-06

    Atrazine molecular imprinted polymers (MIPs) were comparatively synthesized using identical polymer formulation by far-infrared (FIR) radiation and ultraviolet (UV)-induced polymerization, respectively. Equilibrium binding experiments were carried out with the prepared MIPs; the results showed that MIP(uv) possessed specific binding to atrazine compared with their MIP(FIR) radiation counterparts. Scatchard plot's of both MIPs indicated that the affinities of the binding sites in MIPs are heterogeneous and can be approximated by two dissociation-constants corresponding to the high- and low-affinity binding sites. Moreover, several common pesticides including atrazine, cyromazine, metamitron, simazine, ametryn, terbutryn were tested to determine their specificity, similar imprinting factor (IF) and different selectivity index (SI) for both MIPs. Physical characterization of the polymers revealed that the different polymerization methods led to slight differences in polymer structures and performance by scanning electron microscope (SEM), Fourier transform infrared absorption (FT-IR), and mercury analyzer (MA). Finally, both MIPs were used as selective sorbents for solid phase extraction (SPE) of atrazine from lake water, followed by high performance liquid chromatography (HPLC) analysis. Compared with commercial C18 SPE sorbent (86.4%-94.8%), higher recoveries of atrazine in spiked lake water were obtained in the range of 90.1%-97.1% and 94.4%-101.9%, for both MIPs, respectively.

  5. The combined effects of atrazine and lead (Pb): relative microbial activities and herbicide dissipation.

    Science.gov (United States)

    Chen, Qinglin; Wang, Hui; Yang, Baoshan; He, Fei

    2014-04-01

    The experiment was conducted to investigate the effects of single and combined pollution from different concentrations of atrazine (field rate, FR, 2.0 mg kg(-1) and 5 times FR, 10 mg kg(-1)) and lead (Pb) (300 mg kg(-1) and 600 mg kg(-1)) on enzyme activity, basal soil respiration (BSR), and net nitrogen (N) mineralization (NNM) in soil after exposure for 0, 7, 14, 21, and 28 days. In addition, residual atrazine was measured in the samples of combined contamination. Results showed that the notable effects of either or both contaminants on the microbial activity and biological processes. Enzyme activity data demonstrated that the order of sensitivity to contamination was urease>invertase>catalase. BSR was strongly stimulated by atrazine/Pb at the early exposure (0-7 days for single contaminant and 7-14 days for combined contaminants). The stimulation effects on BSR were higher at low concentrations of the contamination (FR and Pb300). The combined treatments of 5FR+Pb600 inhibit BSR and NNM. Overall, the parameters associated with N cycling (urease and NNM) were more sensitive than others. Both Pb concentrations (300 and 600 mg/kg) had little influence on the dissipation of high concentrations of atrazine (5FR) during the 28-day-incubation. This study has provided useful information on potential ecotoxicology effects of combined contamination of atrazine and Pb on relative microbial biological process.

  6. DNA damage and effects on antioxidative enzymes in zebra fish (Danio rerio) induced by atrazine.

    Science.gov (United States)

    Zhu, Lu-Sheng; Shao, Bo; Song, Yan; Xie, Hui; Wang, Jun; Wang, Jin-Hua; Liu, Wei; Hou, Xin-Xin

    2011-01-01

    The effect of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1, 3, 5-triazine) on the activity of some antioxidative enzymes (superoxide dismutase, SOD; catalase, CAT; and guaiacol peroxidase, POD) and DNA damage induced by atrazine were investigated in zebra fish (Danio rerio). Zebra fish were exposed to four different concentrations of atrazine (0, 2.5, 5, and 10 mg/L) for 7, 14, and 21 days, with three replicates of 10 fishes per treatment. Compared to the controls, the SOD activity in the 2.5 mg/L treatment was markedly stimulated in 21 days, while the SOD activities in the 5 mg/L treatment was stimulated at first and then inhibited. The change of CAT activity at 2.5 mg/L was similar to the SOD activity at 2.5 mg/L. The POD activities in the 2.5, 5, and 10 mg/L treatment were markedly higher on days 14 and 21 compared with the controls. The olive tail moments of single-cell gel electrophoresis (SCGE) of zebra fish enhanced after treatment of different doses on days 7, 14, and 21, and significant differences were found compared to the controls. In conclusion, these findings showed the effect regularity of atrazine to zebra fish, and also provide the basis for the future research of adverse effects induced by atrazine in aquatic ecosystems.

  7. Environmentally realistic exposure to the herbicide atrazine alters some sexually selected traits in male guppies.

    Directory of Open Access Journals (Sweden)

    Kausalya Shenoy

    Full Text Available Male mating signals, including ornaments and courtship displays, and other sexually selected traits, like male-male aggression, are largely controlled by sex hormones. Environmental pollutants, notably endocrine disrupting compounds, can interfere with the proper functioning of hormones, thereby impacting the expression of hormonally regulated traits. Atrazine, one of the most widely used herbicides, can alter sex hormone levels in exposed animals. I tested the effects of environmentally relevant atrazine exposures on mating signals and behaviors in male guppies, a sexually dimorphic freshwater fish. Prolonged atrazine exposure reduced the expression of two honest signals: the area of orange spots (ornaments and the number of courtship displays performed. Atrazine exposure also reduced aggression towards competing males in the context of mate competition. In the wild, exposure levels vary among individuals because of differential distribution of the pollutants across habitats; hence, differently impacted males often compete for the same mates. Disrupted mating signals can reduce reproductive success as females avoid mating with perceptibly suboptimal males. Less aggressive males are at a competitive disadvantage and lose access to females. This study highlights the effects of atrazine on ecologically relevant mating signals and behaviors in exposed wildlife. Altered reproductive traits have important implications for population dynamics, evolutionary patterns, and conservation of wildlife species.

  8. Multimedia model of atrazine in plant-soil-groundwater system with a fugacity approach

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The application of atrazine in China during the last ten years has led to some environmental problems. In this paper, the multimedia model of atrazine in soil-plant-groundwater system atBaiyangdian Lake area in Northern China was established using a fugacity approach, and verified with observed values. The model involved 7 environmental compartments which are air, groundwater, soil, corn roots, corn stem, corn leaf and kernel of corn. Theresults showed that the relative errors between calculated and observed values have a mean value of 24.7%, the highest value is 48% and the lowest value is 1.4%. All these values indicated thatthis multimedia model can be used to simulate the environmental fate of atrazine. Both the calculated and observed values of conce ntrations of atrazine in plant compartments are in the ollowing order: in corn roots > in corn stem > in kernel of corn > in corn leaf, it exhibited a good regularity. The prediction results indicated that concentrations of atrazine in the roundwater and kernel of corn will override the limitation of 3L and 0.05 mg/kg respectively.

  9. ATRAZINE ADSORPTION-DESORPTION BEHAVIOR IN DAREHASALUIE KAVAR CORN FIELD SOIL

    Directory of Open Access Journals (Sweden)

    M. Dehghani, S. Nasseri, S. Amin, K. Naddafi, M. Yunesian, M. Taghavi and N. Maleki

    2005-10-01

    Full Text Available Adsorption desorption behaviors of widely applied atrazine soil were studied, employing a batch technique as a case study in Darehasaluie Kavar corn field in Fars Province in 2005. Samples were collected into 0 to 20 cm soil depth, where was cultivated under a crop rotation (corn-wheat during the past 10 years. Sorption kinetics exhibited two phenomena: an immediate rapid sorption (1.31 µg/g soil after 12 hours followed by a slow sorption process (1.37 µg/g soil after 24 hours. Desorption behavior of atrazine was similar to its adsorption, but at a very slower rate. Atrazine desorption efficiencies were much less effective and incomplete even after a long equilibration time (only 9.16% after 96 hours. The adsorption-desorption rate for most of the time was positively related to the amount of applied atrazine and the time required for equilibration (P<0.01. Desorption data exhibited hysteresis phenomena. Atrazine adsorption data described well according to Freundlich (r2=0.95, Langmuir (r2=0.82 and Temkin (r2=0.84 isotherms. However, the fit to Freundlich adsorption model in a non linear form (1/n <1 was closer than the others. Desorption isotherm could be well described by the Temkin (r2=0.96 and Freundlich (r2=0.92 isotherms, but the fit to Temkin model was closer than that of Freundlich.

  10. Acute toxicity of butachlor and atrazine to freshwater green alga Scenedesmus obliquus and cladoceran Daphnia carinata.

    Science.gov (United States)

    He, Hongzhi; Yu, Jing; Chen, Guikui; Li, Wenyang; He, Jinbo; Li, Huashou

    2012-06-01

    Both single and joint toxicity of atrazine and butachlor to freshwater green alga Scenedesmus obliquus and cladoceran Daphnia carinata isolated from South China were investigated in the present study. The 96 h-EC(50) values of atrazine and butachlor to S. obliquus were 0.0147 and 2.31 mg L(-1), while the 48 h-LC(50) values to D. carinata were 60.6 and 3.40 mg L(-1), respectively. These results suggest that atrazine could be highly toxic to S. obliquus and slightly toxic to D. carinata, while butachlor exhibits moderate toxicity to both organisms. The additive indexes of atrazine and butachlor mixtures were -2.68 (-3.02 to -2.32) to S. obliquus and 0.054 (-0.025 to 0.238) to D. carinata, respectively. Therefore, the joint action of two herbicides was significant antagonism to S. obliquus, while significant synergism was not shown to D. carinata. Moreover, significant linear correlation between the natural logarithm of herbicide concentrations and growth rates of alga S. obliquus was observed. Taken together, it is the first study reporting the toxicity endpoints for mixture of atrazine and butachlor against S. obliquus and D. carinata isolated from south China. The present results would be helpful to provide data to assess the ecological risk of both herbicides to aquatic organisms.

  11. Multimedia model of atrazine in plant-soil-groundwater system with a fugacity approach.

    Science.gov (United States)

    Ye, C M; Lei, Z F; Wang, X J; Gong, A J; Zheng, H H

    2001-10-01

    The application of atrazine in China during the last ten years has led to some environmental problems. In this paper, the multimedia model of atrazine in soil-plant-groundwater system at Baiyangdian Lake area in Northern China was established using a fugacity approach, and verified with observed values. The model involved 7 environmental compartments which are air, groundwater, soil, corn roots, corn stem, corn leaf and kernel of corn. The results showed that the relative errors between calculated and observed values have a mean value of 24.7%, the highest value is 48% and the lowest value is 1.4%. All these values indicated that this multimedia model can be used to simulate the environmental fate of atrazine. Both the calculated and observed values of concentrations of atrazine in plant compartments are in the following order: in corn roots > in corn stem > in kernel of corn > in corn leaf, it exhibited a good regularity. The prediction results indicated that concentrations of atrazine in the groundwater and kernel of corn will override the limitation of 3 micrograms/L and 0.05 mg/kg respectively.

  12. GnRH Protein Levels in Atrazine-Treated Axolotls (Ambystoma mexicanum

    Directory of Open Access Journals (Sweden)

    Sarah Leupen

    2008-01-01

    Full Text Available Atrazine is the most widely used agricultural herbicide in the United States and a known endocrine disruptor. In amphibians, it has been shown to cause gonadal malformations, feminization of males, behavioral changes, and immune suppression; however, its mechanism ofaction is unknown. We hypothesized that atrazine reduces the production of gonadotropin releasing hormone (GnRH in the hypothalamus. Axolotls (Ambystoma mexicanum were exposed to atrazine, 10-8 M ß-estradiol-3-benzoate, or no treatment and were sacrificed at 6, 8, and 10 months of age. GnRH neurons were labeled using immunocytochemistry, and labeled neurons were then counted using confocal microscopy. Although no significant difference wasfound in the total number of GnRH neurons, ectopic GnRH expression was seen in some brains. A significant negative correlation was found between presence of ectopic GnRH and number of normal GnRH neurons. Atrazine-treated animals were more likely than control or estrogentreated animals to have ectopic GnRH expression. The data implicate a central site of action of atrazine.

  13. Atrazine Molecular Imprinted Polymers: Comparative Analysis by Far-Infrared and Ultraviolet Induced Polymerization

    Directory of Open Access Journals (Sweden)

    Jun Chen

    2014-01-01

    Full Text Available Atrazine molecular imprinted polymers (MIPs were comparatively synthesized using identical polymer formulation by far-infrared (FIR radiation and ultraviolet (UV-induced polymerization, respectively. Equilibrium binding experiments were carried out with the prepared MIPs; the results showed that MIPuv possessed specific binding to atrazine compared with their MIPFIR radiation counterparts. Scatchard plot’s of both MIPs indicated that the affinities of the binding sites in MIPs are heterogeneous and can be approximated by two dissociation-constants corresponding to the high- and low-affinity binding sites. Moreover, several common pesticides including atrazine, cyromazine, metamitron, simazine, ametryn, terbutryn were tested to determine their specificity, similar imprinting factor (IF and different selectivity index (SI for both MIPs. Physical characterization of the polymers revealed that the different polymerization methods led to slight differences in polymer structures and performance by scanning electron microscope (SEM, Fourier transform infrared absorption (FT-IR, and mercury analyzer (MA. Finally, both MIPs were used as selective sorbents for solid phase extraction (SPE of atrazine from lake water, followed by high performance liquid chromatography (HPLC analysis. Compared with commercial C18 SPE sorbent (86.4%–94.8%, higher recoveries of atrazine in spiked lake water were obtained in the range of 90.1%–97.1% and 94.4%–101.9%, for both MIPs, respectively.

  14. Atrazine and its degradation products in surface and ground waters in Zhangjiakou District, China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A method using the solid phase extraction (SPE) and liquid chromatography-mass spectrometry (LC-MS) to analyse atrazine and its degradation products at levels of low nanograms per liter in water has been developed. The environmental water samples were filtered and then extracted by SPE with a new sulfonation of poly(divinylbenzene-co-N- vinylpyrrolidone) sorbents MCX. HPLC/APCIMS was used for the analysis of atrazine and its degradation products, desethylatrazine (DEA), deisopropylatrazine (DIA), didealkylatrazine (DEDIA), and hydroxyatrazine (HYA). The detection limits ranged from 10-50 ng/L in water samples. Samples were collected from deep wells and a reservoir near a plant that produced atrazine. Atrazine concentration levels in most surface samples were above the limit of the China Surface Water Regulation (3 mg/L). In ground water, the levels of degradation product were more than 0.1 mg/L and 5-10 times greater than those of atrazine. The highest DEA concentration in the groundwater sample taken at the 130 m depth was 7.2 ug/L.

  15. Laboratory degradation studies of 14C-atrazine and -isoproturon in soil from sugarcane cultivated fields under Kenyan tropical conditions.

    Science.gov (United States)

    Getenga, Z M; Dörfler, U; Schroll, R

    2009-06-01

    A study to compare the degradation rates of atrazine (6-chloro-N(2)-ethyl-N(4)-isopropyl-1,3,5-triazine-2,4-diammine) and isoproturon [3-(4-isopropylphenyl)-1,1-dimethylurea] in soils from sugarcane fields with different practices of herbicides application was carried out. (14)C-atrazine was poorly mineralized to (14)CO(2) (1.10% +/- 0.22%) after 139 days of incubation in soil without previous exposure to atrazine. In the same soil also with no previous isoproturon exposure isoproturon was mineralized to (14)CO(2) by 7.70% +/- 0.94%. Atrazine mineralization after 98 days was 13.4% +/- 0.30% in soil which discontinued the use of atrazine in 1997 while it was 89.9% +/- 1.23% in soil in which atrazine is currently being used. The isoproturon mineralization values were 7.24% +/- 0.85% and 22.97% +/- 0.96% in soil which discontinued atrazine and soil currently using atrazine, respectively.

  16. Biomarker Analysis of American Toad (Anaxyrus Americanus) and Grey Tree Frog (Hyla Versicolor) Tadpoles Following Exposure to Atrazine

    Science.gov (United States)

    To better understand the mode of action of atrazine in amphibians, we utilized mass spectrometry-based metabolomics to investigate the biochemical changes in two species of larval amphibians exposed to atrazine. Our objectives were to 1) Use changes in endogenous metabolites to f...

  17. Negative effects of low dose atrazine exposure on the development of effective immunity to FV3 in Xenopus laevis.

    Science.gov (United States)

    Sifkarovski, Jason; Grayfer, Leon; De Jesús Andino, Francisco; Lawrence, B Paige; Robert, Jacques

    2014-11-01

    The recent dramatic increase of the prevalence and range of amphibian host species and populations infected by ranaviruses such as Frog Virus 3 (FV3) raises concerns about the efficacies of amphibian antiviral immunity. In this context, the potential negative effects of water contaminants such as the herbicide atrazine, at environmentally relevant levels, on host antiviral immunity remains unclear. Here we describe the use of the amphibian Xenopus laevis as an ecotoxicology platform to elucidate the consequences of exposure to ecologically relevant doses of atrazine on amphibian antiviral immunity. X. laevis were exposed at tadpole and adult stages as well as during metamorphosis to atrazine (range from 0.1 to 10.0 ppb) prior to infection with FV3. Quantitative analysis of gene expression revealed significant changes in the pro-inflammatory cytokine, TNF-α and the antiviral type I IFN gene in response to FV3 infection. This was most marked in tadpoles that were exposed to atrazine at doses as low 0.1 ppb. Furthermore, atrazine exposure significantly compromised tadpole survival following FV3 infections. In contrast, acute atrazine exposure of mature adult frogs did not induce detectable effects on anti-FV3 immunity, but adults that were exposed to atrazine during metamorphosis exhibited pronounced defects in FV3-induced TNF-α gene expression responses and slight diminution in type I IFN gene induction. Thus, even at low doses, atrazine exposure culminates in impaired development of amphibian antiviral defenses.

  18. Atrazine immobilization on sludge derived biochar and the interactive influence of coexisting Pb(II) or Cr(VI) ions.

    Science.gov (United States)

    Zhang, Weihua; Zheng, Juan; Zheng, Pingping; Qiu, Rongliang

    2015-09-01

    Sludge derived biochars (SDBCs) may have the potential to simultaneously remove heavy metals and organic contaminants in relation to their various active sorption sites for both metal ions and organic compounds. SDBCs have been proven to provide a considerable capacity for immobilizing Pb(II) and Cr(VI) ions in solution, and in this study their ability to sorb atrazine, in addition to their corresponding interactive influences with coexisting metal ions, is extensively investigated. The results indicate that all atrazine adsorption isotherms fit well with the Freundlich equation, and the greatest value of 16.8 mg g(-1) sorption capacity occurred with SDBCs pyrolyzed at 400°C for 2h. The slow sorption kinetics fit well with the Lagergren's 2nd order reaction, and depend upon the initial atrazine concentration, indicating the significance of a site-specific process. The ionic strength-dependence of the atrazine adsorption behavior further consolidates the involvement of the mechanism of the H-bond with hydroxyl groups on SDBC. However, when Pb(II)/Cr(VI) metal ions coexist in solution, they substantially suppress atrazine adsorption, probably because the inner complex between the hydroxyl groups on SDBCs and Pb(II)/Cr(III) ions intrude the weak H-bond with atrazine. As a result, metal adsorption was found to be unaffected by the coexisting atrazine. Therefore, although SDBC is applicable for atrazine removal/immobilization in most of environmentally relevant conditions, a two-step process may be required if heavy metal ions coexist.

  19. Understanding the Effects of Atrazine on Steroidogenesis in rat granulosa and H295R adrenal cortical carcinoma cells

    Science.gov (United States)

    Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) was introduced in the 1950s as a broad spectrum herbicide, and remains one of the most widely used herbicides in the United States. Several studies have suggested that atrazine modifies steroidogenesis and may disrupt r...

  20. Biomarker analysis of American toad (Anaxyrus americanus) and grey tree frog (Hyla versicolor) tadpoles following exposure to atrazine.

    Science.gov (United States)

    The objective of the current study was to use a biomarker-based approach to investigate the influence of atrazine exposure on American toad (Anaxyrus americanus) and grey tree frog (Hyla versicolor) tadpoles. Atrazine is one of the most frequently detected herbicides in environme...

  1. Atrazine Contamination and Potential Health Effects on Freshwater Mussel Uniandra contradens Living in Agricultural Catchment at Nan Province, Thailand

    Directory of Open Access Journals (Sweden)

    Tongchai Thitiphuree

    2013-01-01

    Full Text Available Seasonal cultivation in northern part of Thailand leads to widely uses of agrochemicals especially atrazine herbicide. To examine whether an intensive use of atrazine could lead to contamination in aquatic environment, sediment and water were collected from an agricultural catchment in Nan Province during 2010-2011 and subjected to analysis for atrazine by GC-MS. The results showed that detectable levels of atrazine were found in water (0.16 µg/ml and sediment (0.23 µg/g of the catchment. To monitor potential effects of atrazine on aquatic animals, a freshwater mussel Uniandra contradens was used as a sentinel species for bioaccumulation and potential health effects. Mussels collected from the catchment during 2010-2011 were subjected to analysis for atrazine residue in tissue and condition factor based on body weight and shell length. The results showed that detectable levels of atrazine were found in mussel tissue with the highest level (8.40  2.06 ng/g in late wet season when runoff from heavy rain was evidenced. Condition factor, an indicative of overall health, showed a significant negative correlation with atrazine residue in the tissue. This information could be used as part of the monitoring program for herbicide contamination and potential health effects in agricultural environment.

  2. Creating a portable data-collection system with Microsoft Embedded Visual Tools for the Pocket PC.

    Science.gov (United States)

    Dixon, Mark R

    2003-01-01

    This paper describes an overview and illustrative example for creating a portable data-collection system using Microsoft Embedded Visual Tools for the Pocket PC. A description of the Visual Basic programming language is given, along with examples of computer code procedures for developing data-collection software. Program specifications, strategies for customizing the collection system, and troubleshooting tips are also provided.

  3. Channel coding techniques for wireless communications

    CERN Document Server

    Deergha Rao, K

    2015-01-01

    The book discusses modern channel coding techniques for wireless communications such as turbo codes, low-density parity check (LDPC) codes, space–time (ST) coding, RS (or Reed–Solomon) codes and convolutional codes. Many illustrative examples are included in each chapter for easy understanding of the coding techniques. The text is integrated with MATLAB-based programs to enhance the understanding of the subject’s underlying theories. It includes current topics of increasing importance such as turbo codes, LDPC codes, Luby transform (LT) codes, Raptor codes, and ST coding in detail, in addition to the traditional codes such as cyclic codes, BCH (or Bose–Chaudhuri–Hocquenghem) and RS codes and convolutional codes. Multiple-input and multiple-output (MIMO) communications is a multiple antenna technology, which is an effective method for high-speed or high-reliability wireless communications. PC-based MATLAB m-files for the illustrative examples are provided on the book page on Springer.com for free dow...

  4. Elevated PC responsive B cells and anti-PC antibody production in transgenic mice harboring anti-PC immunoglobulin genes.

    Science.gov (United States)

    Pinkert, C A; Manz, J; Linton, P J; Klinman, N R; Storb, U

    1989-12-01

    The rearrangement of heavy and light chain immunoglobulin genes is necessary for the production of functional antibody molecules. The myeloma MOPC 167 produces specific antibodies to the antigen phosphorylcholine (PC), which is present on bacterial surfaces, fungi and other environmental contaminants. Rearranged heavy and light chain immunoglobulin genes cloned from MOPC 167 were microinjected into mouse eggs. Within the resulting transgenic mice, expression of the transgenes were limited to lymphoid tissues. Transgenic mice produced elevated levels of anti-PC antibodies constitutively, at 16 days of age, when normal non-transgenic mice were not fully immunocompetent. A triggering antigenic stimulus was not necessary to evoke anti-PC immunoglobulin production. Additionally, the frequency of PC-responsive B cells in these transgenic mice was further increased upon specific immunization.

  5. Do the Pc+ pentaquarks have strange siblings?

    Science.gov (United States)

    Lebed, Richard F.

    2015-12-01

    The recent LHCb discovery of states Pc+(4380 ), Pc+(4450 ), believed to be c c ¯u u d pentaquark resonances, begs the question of whether equivalent states with c c ¯→s s ¯ exist, and how they might be produced. The precise analogue to the Pc+ discovery channel Λb→J /ψ K-p , namely, Λc→ϕ π0p , is feasible for this study and indeed is less Cabibbo suppressed, although its limited phase space suggests that evidence of a s s ¯u u d resonance Ps+ would be confined to the kinematic end-point region.

  6. The effects of gestational and chronic atrazine exposure on motor behaviors and striatal dopamine in male Sprague-Dawley rats

    Science.gov (United States)

    Walters, Jennifer L.; Lansdell, Theresa A.; Lookingland, Keith J.; Baker, Lisa E.

    2016-01-01

    This study sought to investigate the effects of environmentally relevant gestational followed by continued chronic exposure to the herbicide, atrazine, on motor function, cognition, and neurochemical indices of nigrostriatal dopamine (DA) activity in male rats. Dams were treated with 100 µg/kg atrazine, 10 mg/kg atrazine, or vehicle on gestational day 1 through postnatal day 21. Upon weaning, male offspring continued daily vehicle or atrazine gavage treatments for an additional six months. Subjects were tested in a series of behavioral assays, and 24 h after the last treatment, tissue samples from the striatum were analyzed for DA and 3,4-dihydroxyphenylacetic acid (DOPAC). At 10 mg/kg, this herbicide was found to produce modest disruptions in motor functioning, and at both dose levels it significantly lowered striatal DA and DOPAC concentrations. These results suggest exposures to atrazine have the potential to disrupt nigrostriatal DA neurons and behaviors associated with motor functioning. PMID:26440580

  7. The effects of gestational and chronic atrazine exposure on motor behaviors and striatal dopamine in male Sprague-Dawley rats.

    Science.gov (United States)

    Walters, Jennifer L; Lansdell, Theresa A; Lookingland, Keith J; Baker, Lisa E

    2015-12-01

    This study sought to investigate the effects of environmentally relevant gestational followed by continued chronic exposure to the herbicide, atrazine, on motor function, cognition, and neurochemical indices of nigrostriatal dopamine (DA) activity in male rats. Dams were treated with 100 μg/kg atrazine, 10mg/kg atrazine, or vehicle on gestational day 1 through postnatal day 21. Upon weaning, male offspring continued daily vehicle or atrazine gavage treatments for an additional six months. Subjects were tested in a series of behavioral assays, and 24h after the last treatment, tissue samples from the striatum were analyzed for DA and 3,4-dihydroxyphenylacetic acid (DOPAC). At 10mg/kg, this herbicide was found to produce modest disruptions in motor functioning, and at both dose levels it significantly lowered striatal DA and DOPAC concentrations. These results suggest that exposures to atrazine have the potential to disrupt nigrostriatal DA neurons and behaviors associated with motor functioning.

  8. Toxic Effects of Atrazine on Reproductive System of Male Rats

    Institute of Scientific and Technical Information of China (English)

    SONG Yang; JIA Zhen Chao; CHEN Jin Yao; HU Jun Xiang; ZHANG Li Shi

    2014-01-01

    Objective This study was designed to evaluate the toxic effects of Atrazine (ATZ) on the reproductive system of male rats. Methods Male Sprague-Dawley rats were exposed to ATZ by gavage at dosages of 0, 38.5, 77, and 154 mg/kg bw/day for 30 d. The toxic effects of ATZ to rats were assessed through histopathologcal observation, spermatozoa quality evaluation, testicular marker enzyme indicators, antioxidant capacity and reproductive hormone levels. Results Significant adverse effects on reproductive system were observed in rats exposed to ATZ at different dosages compared with 0 mg/kg group, including an irregular and disordered arrangement of the seminiferous epithelium in 154 mg/kg group;a decreased spermatozoa number and an increased spermatozoa abnormality rate in 77 and 154 mg/kg groups;decreased levels of acid phosphatase (ACP), alkaline phosphatase (AKP), lactic dehydrogenase (LDH), and succinate dehydrogenase (SDH) with the increasing of ATZ concentration; a decreased level of total antioxidant capacity (TAC) in a dose-dependent manner, and a decreased reduced glutathione (GSH) level and an increased malondialdehyde (MDA) content in 154 mg/kg group;and decreased serum levels of testosterone (T) and inhibin-B (INH-B) and an increased serum level of follicle stimulating hormone (FSH) in 77 and 154 mg/kg groups, and an increased serum level of luteinizing hormone (LH) in 154 mg/kg group. Conclusion These results suggested that relatively high doses of ATZ could exert reproductive toxicity of male rats.

  9. Regression models for estimating concentrations of atrazine plus deethylatrazine in shallow groundwater in agricultural areas of the United States

    Science.gov (United States)

    Stackelberg, Paul E.; Barbash, Jack E.; Gilliom, Robert J.; Stone, Wesley W.; Wolock, David M.

    2012-01-01

    Tobit regression models were developed to predict the summed concentration of atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine] and its degradate deethylatrazine [6-chloro-N-(1-methylethyl)-1,3,5,-triazine-2,4-diamine] (DEA) in shallow groundwater underlying agricultural settings across the conterminous United States. The models were developed from atrazine and DEA concentrations in samples from 1298 wells and explanatory variables that represent the source of atrazine and various aspects of the transport and fate of atrazine and DEA in the subsurface. One advantage of these newly developed models over previous national regression models is that they predict concentrations (rather than detection frequency), which can be compared with water quality benchmarks. Model results indicate that variability in the concentration of atrazine residues (atrazine plus DEA) in groundwater underlying agricultural areas is more strongly controlled by the history of atrazine use in relation to the timing of recharge (groundwater age) than by processes that control the dispersion, adsorption, or degradation of these compounds in the saturated zone. Current (1990s) atrazine use was found to be a weak explanatory variable, perhaps because it does not represent the use of atrazine at the time of recharge of the sampled groundwater and because the likelihood that these compounds will reach the water table is affected by other factors operating within the unsaturated zone, such as soil characteristics, artificial drainage, and water movement. Results show that only about 5% of agricultural areas have greater than a 10% probability of exceeding the USEPA maximum contaminant level of 3.0 μg L-1. These models are not developed for regulatory purposes but rather can be used to (i) identify areas of potential concern, (ii) provide conservative estimates of the concentrations of atrazine residues in deeper potential drinking water supplies, and (iii) set priorities

  10. Atrazine biodegradation efficiency, metabolite detection, and trzD gene expression by enrichment bacterial cultures from agricultural soil.

    Science.gov (United States)

    Solomon, Robinson David Jebakumar; Kumar, Amit; Satheeja Santhi, Velayudhan

    2013-12-01

    Atrazine is a selective herbicide used in agricultural fields to control the emergence of broadleaf and grassy weeds. The persistence of this herbicide is influenced by the metabolic action of habituated native microorganisms. This study provides information on the occurrence of atrazine mineralizing bacterial strains with faster metabolizing ability. The enrichment cultures were tested for the biodegradation of atrazine by high-performance liquid chromatography (HPLC) and mass spectrometry. Nine cultures JS01.Deg01 to JS09.Deg01 were identified as the degrader of atrazine in the enrichment culture. The three isolates JS04.Deg01, JS07.Deg01, and JS08.Deg01 were identified as efficient atrazine metabolizers. Isolates JS04.Deg01 and JS07.Deg01 produced hydroxyatrazine (HA) N-isopropylammelide and cyanuric acid by dealkylation reaction. The isolate JS08.Deg01 generated deethylatrazine (DEA), deisopropylatrazine (DIA), and cyanuric acid by N-dealkylation in the upper degradation pathway and later it incorporated cyanuric acid in their biomass by the lower degradation pathway. The optimum pH for degrading atrazine by JS08.Deg01 was 7.0 and 16S rDNA phylogenetic typing identified it as Enterobacter cloacae strain JS08.Deg01. The highest atrazine mineralization was observed in case of isolate JS08.Deg01, where an ample amount of trzD mRNA was quantified at 72 h of incubation with atrazine. Atrazine bioremediating isolate E. cloacae strain JS08.Deg01 could be the better environmental remediator of agricultural soils and the crop fields contaminated with atrazine could be the source of the efficient biodegrading microbial strains for the environmental cleanup process.

  11. Atrazine biodegradation efficiency, metabolite detection, and trzD gene expression by enrichment bacterial cultures from agricultural soil

    Institute of Scientific and Technical Information of China (English)

    Robinson David Jebakumar SOLOMON; Amit KUMAR; Velayudhan SATHEEJA SANTHI

    2013-01-01

    Atrazine is a selective herbicide used in agricultural fields to control the emergence of broadleaf and grassy weeds. The persistence of this herbicide is influenced by the metabolic action of habituated native microor-ganisms. This study provides information on the occurrence of atrazine mineralizing bacterial strains with faster me-tabolizing ability. The enrichment cultures were tested for the biodegradation of atrazine by high-performance liquid chromatography (HPLC) and mass spectrometry. Nine cultures JS01.Deg01 to JS09.Deg01 were identified as the degrader of atrazine in the enrichment culture. The three isolates JS04.Deg01, JS07.Deg01, and JS08.Deg01 were identified as efficient atrazine metabolizers. Isolates JS04.Deg01 and JS07.Deg01 produced hydroxyatrazine (HA) N-isopropylammelide and cyanuric acid by dealkylation reaction. The isolate JS08.Deg01 generated deethylatrazine (DEA), deisopropylatrazine (DIA), and cyanuric acid by N-dealkylation in the upper degradation pathway and later it incorporated cyanuric acid in their biomass by the lower degradation pathway. The optimum pH for degrading atrazine by JS08.Deg01 was 7.0 and 16S rDNA phylogenetic typing identified it as Enterobacter cloacae strain JS08.Deg01. The highest atrazine mineralization was observed in case of isolate JS08.Deg01, where an ample amount of trzD mRNA was quantified at 72 h of incubation with atrazine. Atrazine bioremediating isolate E. cloacae strain JS08.Deg01 could be the better environmental remediator of agricultural soils and the crop fields contaminated with atrazine could be the source of the efficient biodegrading microbial strains for the environmental cleanup process.

  12. Degradation of atrazine photoinduced by Fe(III)-pyruvate complexes in the aqueous solution.

    Science.gov (United States)

    Zhang, Changbo; Wang, Lei; Pan, Gang; Wu, Feng; Deng, Nansheng; Mailhot, Gilles; Mestankova, Hana; Bolte, Michele

    2009-09-30

    The composition and photochemical properties of the Fe(III)-Pyr complexes in the aqueous solution was studied in this work. Fe(III) was complexed by Pyr in the ratio of 1:3. The photochemical processes occurred in the Fe(III)-Pyr system was studied in detail. Fe(II) was the main intermediate product. DMPO was used as scavenger to determine the active radicals, such as *OH, CO3*-, CO2*-, H and RCO2* by ESR. Photodegradation of atrazine induced by the photolysis of Fe(III)-Pyr was studied and the reaction kinetics fitted the first order reaction. Parameters such as pH, the initial concentrations of Fe(III), pyruvate (Pyr) and atrazine were all investigated. Photoproducts were detected by the LC-MS and the photodegradation scheme was proposed. *OH radical was the main pathway of atrazine degradation.

  13. Exploration of Experimental Data On Atrazine Degradation In Relation To Environmental Conditions

    Science.gov (United States)

    Putters, B.

    The objective of this project is to find the soil factors which dominate the degradation behaviour of atrazine (pesticide). From published experiments on atrazine degradation in the subsurface, the available data concerning soil characteristics, experimental conditions, and the measured degra- dation rates were put into a database. From literature, environmental conditions could be related to degradation rates. These relationships were tested by exploration of the dataset by statistical techniques. In general, the degradation is mainly determined by the availability of the substrate (atrazine) and the biological activity. More specific re- lationships could be derived from the dataset and will be presented at the conference. The relationships can also be used for degradation rate estimates for modelling pur- poses.

  14. Genotoxicity of mixtures of glyphosate and atrazine and their environmental transformation products before and after photoactivation.

    Science.gov (United States)

    Roustan, A; Aye, M; De Meo, M; Di Giorgio, C

    2014-08-01

    The photo-inducible cytogenetic toxicity of glyphosate, atrazine, aminomethyl phosphoric acid (AMPA), desethyl-atrazine (DEA), and their various mixtures was assessed by the in vitro micronucleus assay on CHO-K1 cells. Results demonstrated that the cytogenetic potentials of pesticides greatly depended on their physico-chemical environment. The mixture made with the four pesticides exhibited the most potent cytogenetic toxicity, which was 20-fold higher than those of the most active compound AMPA, and 100-fold increased after light-irradiation. Intracellular ROS assessment suggested the involvement of oxidative stress in the genotoxic impact of pesticides and pesticide mixtures. This study established that enhanced cytogenetic activities could be observed in pesticide mixtures containing glyphosate, atrazine, and their degradation products AMPA and DEA. It highlighted the importance of cocktail effects in environmental matrices, and pointed out the limits of usual testing strategies based on individual molecules, to efficiently estimate environmental risks.

  15. Enhanced adsorption of atrazine from aqueous solution by molecularly imprinted TiO2 film

    Science.gov (United States)

    Zhang, Chunjing; Yan, Jinlong; Zhang, Chunxiao; Yang, Zhengpeng

    2012-07-01

    TiO2 film imprinted by atrazine molecule at the surface of quartz crystal was prepared using molecular imprinting and surface sol-gel process. The molecularly imprinted TiO2 film was characterized by scanning electron microscopy and cyclic voltammetry, and the atrazine adsorption was investigated by quartz crystal microbalance (QCM) technique. In comparison with non-imprinted TiO2 film, the molecularly imprinted TiO2 film exhibits high selectivity for atrazine, better reversibility and a much higher adsorption capacity for the target molecule, the adsorption equilibrium constant estimated from the in situ frequency measurement is about 6.7 × 104 M-1, which is thirteen times higher than that obtained on non-imprinted TiO2 film.

  16. Rapid treatment of atrazine-contaminated water by nickel/iron bimetallic system

    Institute of Scientific and Technical Information of China (English)

    WEI Hong; TONG Shao-ping; WANG Hong-yu; LIU Wei-ping

    2004-01-01

    The utility of nickel/iron in the remediation of atrazine-contaminated water was investigated. The experimental results showed that nickel/iron had effective catalytic activity in dechlorinating atrazine under acidic conditions. The dechlorination reaction approximately followed the first-order kinetics under the experimental conditions(nickel/iron:1.0 g/250 ml;Catrazine=20.0 mg/L), the reaction rate increased with decreasing pH value of the reaction solution and increasing the proportion of Ni:Fe within 2.95%. For condition with 2.95% nickel/iron, the reaction rate constants were 0.07518(R=0.9927), 0.06212(R=0.9846) and 0.00131 min-1(R=0.9565) at pH=2.0, 3.0 and 4.0, respectively. HPLC analysis was used to monitor the decline of atrazine concentration.

  17. Histopathological effects of atrazine on gills of Caspian kutum Rutilus frisii kutum fingerlings.

    Science.gov (United States)

    Khoshnood, Zahra; Jamili, Shahla; Khodabandeh, Saber

    2015-04-08

    The use of chemical pesticides has increased environmental pollution and affects fishes as non-target organisms. To investigate the toxic effects of the widely used herbicide atrazine on Caspian kutum Rutilus frisii kutum fingerlings, fish were exposed to a sublethal concentration of half LC50 for 96 h. The main alterations visible in the gill tissue were detachment of the epithelium of the lamellae, necrosis, lamellar fusion, hyperplasia, club shaped lamellae, collapse of the lamellae, shrinkage and curling of the lamellae, and ultrastructural alterations such as necrosis of the apical microridges of the pavement cells. Results also showed that the gill ionocytes were fewer in number and larger in size in the atrazine-exposed fish. Atrazine appears to be highly toxic to Caspian kutum fingerlings even at a sublethal concentration (12.47 mg l(-1)) and acute exposure. This toxicity could affect gill respiration and ion regulation function of fingerlings by damaging tissue, pavement cells, and ionocytes.

  18. The PC index: review of methods

    Directory of Open Access Journals (Sweden)

    H. McCreadie

    2010-10-01

    Full Text Available The Polar Cap (PC index is a controversial topic within the IAGA scientific community. Since 1997 discussions of the validity of the index to be endorsed as an official IAGA index have ensued. There is no doubt as to the scientific merit of the index which is not discussed here. What is in doubt is the methodology of the derivation of the index by different groups. The Polar Cap index (PC: PCN, northern; PCS, southern described in Troshichev et al. (2006 and Stauning et al. (2006, both termed the "unified PC index", and the PCN index routinely derived at DMI are inspected using only available published literature. They are found to contain different derivation procedures, thus are not unified. The descriptions of the derivation procedures are found to not be adequate to independently derive the PC indices.

  19. Modeling the potential effects of atrazine on aquatic communities in midwestern streams.

    Science.gov (United States)

    Bartell, Steven M; Brain, Richard A; Hendley, Paul; Nair, Shyam K

    2013-10-01

    The comprehensive aquatic systems model for atrazine (CASM(ATZ)) estimates the potential toxic effects of atrazine on populations of aquatic plants and consumers in a generic lower-order midwestern stream. The CASM(ATZ) simulates the daily production of 20 periphyton and 6 aquatic vascular plant species. The modeled consumer community consists of 17 functionally defined species of zooplankton, benthic invertebrates, bacteria, and fish. Daily values of population biomass (grams of carbon per square meter) are calculated as nonlinear functions of population bioenergetics, physical-chemical environmental parameters, grazing/predator-prey interactions, and population-specific direct and indirect responses to atrazine. The CASM(ATZ) uses Monte Carlo methods to characterize the implications of phenotypic variability, environmental variability, and uncertainty associated with atrazine toxicity data in estimating the potential impacts of time-varying atrazine exposures on population biomass and community structure. Comparisons of modeled biomass values for plants and consumers with published data indicate that the generic reference simulation realistically describes ecological production in lower-order midwestern streams. Probabilistic assessments were conducted using the CASM(ATZ) to evaluate potential modeled changes in plant community structure resulting from measured atrazine exposure profiles in 3 midwestern US streams representing watersheds highly vulnerable to runoff. Deviation in the median values of maximum 30-d average Steinhaus similarity index ranged from 0.09% to 2.52% from the reference simulation. The CASM(ATZ) could therefore be used for the purposes of risk assessment by comparison of site monitoring-based model output to a biologically relevant Steinhaus similarity index level of concern. Used as a generic screening technology or in site-specific applications, the CASM(AT) provides an effective, coherent, and transparent modeling framework for assessing

  20. Atrazine Adsorption Behavior on a Fluvo-Aquic Soil as Influenced by Contact Periods

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A batch experiment was performed to investigate nonequilibrium adsorption behavior of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) on a fluvo-aquic soil. The amount of atrazine sorbed increased with increasing adsorption contact periods. For a range of initial atrazine concentrations, the percentage of atrazine sorbed within 24 h ranged from 24% to 77% of the observed total amount sorbed for the longest contact period; when adsorption contact periods were more than 72 h, the deviations in curves fitted using a nonlinear Freundlich equation gradually became less. The opposite trend was observed for the atrazine concentrations in solution. The effect of adsorption contact periods on atrazine adsorption behavior was evaluated by interpreting the temporal variations in linear and nonlinear Freundlich equation parameters obtained from the phase-distribution relationships. As the adsorption contact period increased, the nonlinear Freundlich capacity coefficient kf showed a significant linear increase (r2 = 0.9063, P < 0.001). However, a significant negative linear correlation was observed for the nonlinear coefficient n, a dimensionless parameter (r2 = 0.5666,P < 0.05).Furthermore, the linear distribution coefficient kd ranged from 0.38 to 1.44 and exhibited a significant linear correlation to the adsorption contact period (r2 = 0.72, P < 0.01). The parameters k f and n obtained from a time-dependent isotherm rather than the distribution coefficient kd estimated using the linear Freundlich equation were more appropriate to predict the herbicide residue in the field and thus more meaningful for environmental assessment.

  1. Degradation of Herbicides Atrazine and Bentazone Applied Alone and in Combination in Soils

    Institute of Scientific and Technical Information of China (English)

    LI Ke-Bin; CHENG Jing-Tao; WANG Xiao-Fang; ZHOU Ying; LIU Wei-Ping

    2008-01-01

    The application of a mixture of bentazone (3-isopropyl-lH-2,1,3-benzothiadiazin-4(3H)-one-2,2-dioxide) and atrazine (6-chloro-N2-ethyl-N4-isopropy1-1,3,5-triazine-2,4-diamine) is a practical approach to enhance the herbicidal effect.Labo-ratory incubation experiments were performed to study the degradation of bentazone and atrazine applied in combination and individually in maize rhizosphere and non-rhizosphere soils.After a lag phase,the degradation of each individual herbicide in the non-autoclaved soil could be adequately described using a first-order kinetic equation.During a 30-d in-cubation,in the autoclaved rhizosphere soil,bentazone and atrazine did not noticeably degrade,but in the non-autoclaved soil,they rapidly degraded in both non-rhizosphere and rhizosphere soils with half-lives of 19.9 and 20.2 d for bentazone and 29.1 and 25.7 d for atrazine,respectively.The rhizosphere effect significantly enhanced the degradation of atrazine,but had no significant effect on bentazone.These results indicated that biological degradation accounted for the degrada-tion of both herbicides in the soil.When compared with the degradation of the herbicide applied alone,the degradation rates of the herbicides applied in combination in the soils were lower and the lag phase increased.With the addition of a surfactant,Tween-20,a reduced lag phase of degradation was observed for both herbicides applied in combination.The degradation rate of bentazone accelerated,whereas that of atrazine remained nearly unchanged.Thus,when these two herbicides were used simultaneously,their persistence in the soil was generally prolonged,and the environmental contamination potential increased.

  2. Sorption of Atrazine in Tropical Soil by Biochar Prepared from Cassava Waste

    Directory of Open Access Journals (Sweden)

    Hui Deng

    2014-09-01

    Full Text Available Biochar (BC is a carbonaceous and porous product generated from the incomplete combustion of biomass and has been recognized as an efficient adsorbent. This study evaluated the ability of BC to sorb atrazine pesticide in tropical soil, and explored potential environmental values of BC on mitigating organic micro-pollutants. BC was produced from cassava waste via pyrolyzation under oxygen-limiting conditions at 350, 550, and 750 °C (MS350, MS550, and MS750, respectively. Three biochars were characterized and investigated as sorbents for the removal atrazine from tropical soil. BC pyrolyzed at higher temperatures more quickly reached equilibrium. The pseudo-second-order model perfectly simulated the sorption kinetics for atrazine with the coefficients R2 above 0.996, and the sorption amount at equilibrium (qe was 0.016 mg/g for MS350, 0.025 mg/g for MS550 and 0.050 mg/g for MS750. The isotherms of MS350 displayed relatively linear behavior, whereas the sorption of atrazine on MS550 and MS750 followed a nonlinear isotherm. The sorption data were well described by the Freundlich model with logKF of 0.476 for MS350, 0.771 for MS550, 1.865 for MS750. A thermodynamic study indicated that the sorption of atrazine in BC-added soil was a spontaneous and endothermic process and was primarily controlled by physisorption. In addition, lower pH was conducive to the sorption of atrazine in BC-added soil.

  3. Photodegradation of chlorbromuron, atrazine, and alachlor in aqueous systems under solar irradiation

    Directory of Open Access Journals (Sweden)

    Cristina Lizama Bahena

    2006-01-01

    Full Text Available Homogeneous and heterogeneous aqueous systems of the herbicides of chlorbromuron, atrazine, and alachlor were irradiated with a nonexpensive solar irradiation using a photoreactor with recirculation. Photodegradation of these herbicides occurred in both aqueous systems; however the presence of TiO2 clearly accelerated the degradation of the three herbicides in comparison with direct photolysis. Degradation was followed by measuring the chemical oxygen demand (COD as a function of reaction time for each aqueous system. Over 90% of COD abatement in the heterogeneous aqueous system was obtained in a short time period showing that mineralization of chlorbromuron, atrazine, and alachlor was achieved.

  4. Update of Watershed Regressions for Pesticides (WARP) for Predicting Atrazine Concentration in Streams

    Science.gov (United States)

    Stone, Wesley W.; Gilliom, Robert J.

    2009-01-01

    Regression models for predicting atrazine concentrations in streams were updated by incorporating refined annual atrazine-use estimates and by adding an explanatory variable representing annual precipitation characteristics. The updated Watershed Regressions for Pesticides (WARP) models enable improved predictions of specific pesticide-concentration statistics for unmonitored streams. for unmonitored streams. Separate WARP regression models were derived for selected percentiles (5th, 10th, 15th, 25th, 50th, 75th, 85th, 90th and 95th), annual mean, annual maximum, and annual maximum moving-average (21-, 60-, and 90-day durations) concentration statistics. Development of the regression models involved the same model-development data, model-validation data, and regression methods as those used in the original development of WARP. The original WARP models were based on atrazine-use estimates from either 1992 or 1997. This update of the WARP models incorporates annual atrazine-use estimates. In addition, annual precipitation data were evaluated as potential explanatory variables. as potential explanatory variables. The updated WARP models include the same five explanatory variables and transformations that were used in the original WARP models, including the new annual atrazine-use data. The models also include a sixth explanatory variable, total precipitation during May and June of the year of sampling. The updated WARP models account for as much as 82 percent of the variability in the concentration statistics among the 112 sites used for model development, whereas previous WARP models accounted for no more than 77 percent. Concentration statistics predicted by the 95th percentile, annual mean, annual maximum and annual maximum moving-average concentration models were within a factor of 10 of the observed concentration statistics for most of the model development and validation sites. Overall, performance of the models for the development and validation sites supports

  5. Method for Estimating Annual Atrazine Use for Counties in the Conterminous United States, 1992-2007

    Science.gov (United States)

    Thelin, Gail P.; Stone, Wesley W.

    2010-01-01

    A method was developed to estimate annual atrazine use during 1992 to 2007 on sixteen crops and four agricultural land uses. For each year, atrazine use was estimated for all counties in the conterminous United States (except California) by combining (1) proprietary data from the Doane Marketing Research-Kynetec (DMRK) AgroTrak database on the mass of atrazine applied to agricultural crops, (2) county harvested crop acreage, by county, from the 1992, 1997, 2002, and 2007 Censuses of Agriculture, and (3) annual harvested crop acreage from National Agriculture Statistics Service (NASS) for non-Census years. DMRK estimates of pesticide use on individual crops were derived from surveys of major field crops and selected specialty crops in multicounty areas referred to as Crop Reporting Districts (CRD). The CRD-level atrazine-use estimates were disaggregated to obtain county-level application rates by dividing the mass (pounds) of pesticides applied to a crop by the acreage of that crop in the CRD to yield a rate per harvested acre. When atrazine-use estimates were not available for a CRD, crop, or year, an estimated rate was developed following a hierarchy of decision rules that checked first for the availability of a crop application rate from surveyed atrazine application rate(s) for adjacent CRDs for a specific year, and second, the rates from surveyed CRDs within for U.S. Department of Agriculture Farm Production Regions for a specific year or multiple years. The estimation method applied linear interpolation to estimate crop acreage for years when harvested acres for a crop and county were not reported in either the Census of Agriculture or the NASS database, but were reported by these data sources for other years for that crop and county. Data for atrazine use for the counties in California was obtained from farmers' reports of pesticide use collected and published by the California Department of Pesticide Regulation-Pesticide Use Reporting (DPR-PUR) because these

  6. Separation and detection of Atrazine and Paraquat based on gold nanochannels

    Directory of Open Access Journals (Sweden)

    XIE Li

    2014-02-01

    Full Text Available Gold nanochannels were prepared by electroless deposition of Au onto the inner wall of porous polycarbonate membrane.The surfaces of the as;prepared gold nanochannels are negatively charged and hydrophilic.In aqueous solution,paraquat exists in the hydrophilic cationic form,while atrazine exists in the form of hydrophobic neutral molecule due to their structural difference.Under the applied electric field,paraquat can migrate through the nanotubules due to electrophoresis,resulting in the separation of atrazine and paraquat.

  7. Effect of Copper, Irgarol and Atrazine on Epiphytes Attached to Artificial Devices for Coastal Ecotoxicology Bioassays.

    Science.gov (United States)

    Crespo, Elena; Lozano, Pablo; Blasco, Julián; Moreno-Garrido, Ignacio

    2013-10-12

    Toxic effects of copper, atrazine and irgarol were evaluated on epiphytes attached to mimes (artificial devices that mimic the morphology of seagrasses) in order to check sensitivity of this biological group. Tube-dwelling diatoms were the major component of the epiphyte community. Superoxide dismutase activity was enhanced by exposure to 25 and 50 μg L(-1) of atrazine; the organism generates this antioxidant response to prevent cellular damage by removing reactive oxygen substances produced by oxidative stress. The measurement of antioxidant enzymatic activity in epiphytes could be a useful technique for ecotoxicology monitoring in marine coastal environments.

  8. Holographic codes

    CERN Document Server

    Latorre, Jose I

    2015-01-01

    There exists a remarkable four-qutrit state that carries absolute maximal entanglement in all its partitions. Employing this state, we construct a tensor network that delivers a holographic many body state, the H-code, where the physical properties of the boundary determine those of the bulk. This H-code is made of an even superposition of states whose relative Hamming distances are exponentially large with the size of the boundary. This property makes H-codes natural states for a quantum memory. H-codes exist on tori of definite sizes and get classified in three different sectors characterized by the sum of their qutrits on cycles wrapped through the boundaries of the system. We construct a parent Hamiltonian for the H-code which is highly non local and finally we compute the topological entanglement entropy of the H-code.

  9. Intracranial artery velocity measurement using 4D PC MRI at 3 T: comparison with transcranial ultrasound techniques and 2D PC MRI

    Energy Technology Data Exchange (ETDEWEB)

    Meckel, Stephan [University Hospital Freiburg, Department of Neuroradiology, Freiburg (Germany); Leitner, Lorenz; Schubert, Tilman [University Hospital Basel, Institute of Radiology, Basel (Switzerland); Bonati, Leo H.; Lyrer, Philippe [University Hospital Basel, Department of Neurology, Basel (Switzerland); Santini, Francesco [University Hospital Basel, Department of Radiological Physics, Institute of Radiology, Basel (Switzerland); Stalder, Aurelien F. [Xuanwu Hospital - Capital Medical University, Department of Radiology, Beijing (China); Markl, Michael [Northwestern University Feinberg School of Medicine, Departments of Radiology and Biomedical Engineering, Chicago (United States); Wetzel, Stephan G. [Neuroradiology, Swiss Neuro Institute, Klinik Hirslanden, Zurich (Switzerland)

    2013-04-15

    4D phase contrast MR imaging (4D PC MRI) has been introduced for spatiotemporal evaluation of intracranial hemodynamics in various cerebrovascular diseases. However, it still lacks validation with standards of reference. Our goal was to compare blood flow quantification derived from 4D PC MRI with transcranial ultrasound and 2D PC MRI. Velocity measurements within large intracranial arteries [internal carotid artery (ICA), basilar artery (BA), and middle cerebral artery (MCA)] were obtained in 20 young healthy volunteers with 4D and 2D PC MRI, transcranial Doppler sonography (TCD), and transcranial color-coded duplex sonography (TCCD). Maximum velocities at peak systole (PSV) and end diastole (EDV) were compared using regression analysis and Bland-Altman plots. Correlation of 4D PC MRI measured velocities was higher in comparison with TCD (r = 0.49-0.66) than with TCCD (0.35-0.44) and 2D PC MRI (0.52-0.60). In mid-BA and ICA C7 segment, a significant correlation was found with TCD (0.68-0.81 and 0.65-0.71, respectively). No significant correlation was found in carotid siphon. On average over all volunteers, PSVs and EDVs in MCA were minimally underestimated compared with TCD/TCCD. Minimal overestimation of velocities was found compared to TCD in mid-BA and ICA C7 segment. 4D PC MRI appears as valid alternative for intracranial velocity measurement consistent with previous reference standards, foremost with TCD. Spatiotemporal averaging effects might contribute to vessel size-dependent mild underestimation of velocities in smaller (MCA), and overestimation in larger-sized (BA and ICA) arteries, respectively. Complete spatiotemporal flow analysis may be advantageous in anatomically complex regions (e.g. carotid siphon) relative to restrictions of ultrasound techniques. (orig.)

  10. Veterinary Antibiotic Effects on Atrazine Degradation and Soil Microorganisms.

    Science.gov (United States)

    Nordenholt, Rebecca M; Goyne, Keith W; Kremer, Robert J; Lin, Chung-Ho; Lerch, Robert N; Veum, Kristen S

    2016-03-01

    Veterinary antibiotics (VAs) in manure applied to agricultural lands may change agrichemical degradation by altering soil microbial community structure or function. The objectives of this study were to investigate the influence of two VAs, sulfamethazine (SMZ) and oxytetracycline (OTC), on atrazine (ATZ) degradation, soil microbial enzymatic activity, and phospholipid fatty acid (PLFA) markers. Sandy loam soil with and without 5% swine manure (w/w) was amended with 0 or 500 μg kgC radiolabeled ATZ and with 0, 100, or 1000 μg kg SMZ or OTC and incubated at 25°C in the dark for 96 d. The half-life of ATZ was not significantly affected by VA treatment in the presence or absence of manure; however, the VAs significantly ( degradation by 22%, reduced ATZ mineralization by 50%, and increased the half-life of ATZ by >10 d. The VAs had limited adverse effects on the microbial enzymes β-glucosidase and dehydrogenase in soils with and without manure. In contrast, manure application stimulated dehydrogenase activity and altered chlorinated ATZ metabolite profiles. Concentrations of PLFA markers were reduced by additions of ATZ, manure, OTC, and SMZ; adverse additive effects of combined treatments were noted for arbuscular mycorrhizal fungi and actinobacteria. In this work, the VAs did not influence persistence of the ATZ parent compound or chlorinated ATZ metabolite formation and degradation. However, reduced CO evolved from VA-treated soil suggests an inhibition to the degradation of other ATZ metabolites due to an altered soil microbial community structure.

  11. Role of eaq⁻, ·OH and H· in radiolytic degradation of atrazine: a kinetic and mechanistic approach.

    Science.gov (United States)

    Khan, Javed Ali; Shah, Noor S; Nawaz, Shah; Ismail, M; Rehman, Faiza; Khan, Hasan M

    2015-05-15

    The degradation of atrazine was investigated in aqueous solution by gamma-ray irradiation. 8.11 μM initial atrazine concentration could be completely removed in N₂ saturated solution by applying 3500 Gy radiation dose at a dose rate of 296 Gy h(-1). Significant removal of atrazine (i.e., 39.4%) was observed at an absorbed dose of 1184 Gy in air saturated solution and the removal efficiency was promoted to 50.5 and 65.4% in the presence of N₂O and N₂ gases, respectively. The relative contributions of hydrated electron, hydroxyl radical and hydrogen radical toward atrazine degradation were determined as ratio of observed dose constant (kobs) and found to be 5: 3: 1 for keaq(-): k·OH: kH·, respectively. The degradation efficiency of atrazine was 69.5, 55.6 and 37.3% at pH 12.1, 1.7 and 5.7, respectively. A degradation mechanism was proposed based on the identified degradation by-products by gas chromatography-mass spectrometry. Taking the relative contributions of oxidative and reductive species to atrazine degradation into account, reductive pathway proved to be a better approach for the radiolytic treatment of atrazine contaminated water.

  12. Atrazine degradation by a simple consortium of Klebsiella sp. A1 and Comamonas sp. A2 in nitrogen enriched medium.

    Science.gov (United States)

    Yang, Chunyu; Li, Yang; Zhang, Kun; Wang, Xia; Ma, Cuiqing; Tang, Hongzhi; Xu, Ping

    2010-02-01

    A simple consortium consisted of two members of Klebsiella sp. A1 and Comamonas sp. A2 was isolated from the sewage of a pesticide mill in China. One member of Klebsiella sp. A1 is a novel strain that could use atrazine as the sole carbon and nitrogen source. The consortium showed high atrazine-mineralizing efficiency and about 83.3% of 5 g l(-1) atrazine could be mineralized after 24 h degradation. Contrary to many other reported microorganisms, the consortium was insensitive to some nitrogenous fertilizers commonly used, not only in presence of 200 mg l(-1) atrazine but also in 5 g l(-1) atrazine mediums. After 24 h incubation, 200 mg l(-1) atrazine was completely mineralized despite of the presence of urea, (NH(4))(2)CO(3) and (NH(4))(2)HPO(4) in the medium. Very minor influence was observed when NH(4)Cl was added as additional nitrogen source. Advantages of the simple consortium, high mineralizing efficiency and insensitivity to most of exogenous nitrogen sources, all suggested application potential of the consortium for the bioremediation of atrazine-contaminated soils and waters.

  13. The long-term effects of the herbicide atrazine on the dopaminergic system following exposure during pubertal development.

    Science.gov (United States)

    Li, Yanshu; Sun, Yan; Yang, Junwei; Wu, Yanping; Yu, Jia; Li, Baixiang

    2014-03-15

    Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) is used worldwide as a herbicide, and its presence in the environment has resulted in documented human exposure. Atrazine has been shown to cause dopaminergic neurotoxicity. The juvenile period is particularly vulnerable to environmental agents, but only few studies have investigated the long-term effects of atrazine following exposure during the pubertal development. Therefore, we evaluated the effects of a 41-day exposure to atrazine on the dopaminergic system in rats. Sprague-Dawley rats were treated orally with atrazine at 25 or 50mg/kg bw, daily from postnatal day 22 to 62. The content of dopamine (DA) was examined in striatum samples by HPLC-FL, and the mRNA and protein expression of tyrosine hydroxylase (TH), orphan nuclear hormone (Nurr1), dopamine transporter (DAT) and vesicular monoaminetransporter 2 (VMAT2) were examined in samples of the ventral mid-brain by use of fluorescence PCR and Western-blot analysis when the rats reached the age of one year. Exposure of juvenile rats to the high dose of atrazine led to reduced levels of DA and mRNA of Nurr1 in one-year-old animals. This study shows that the long-term adverse effects of atrazine on the dopaminergic system have a special relevance after juvenile exposure.

  14. The possible role of hydroxylation in the detoxification of atrazine in mature vetiver (Chrysopogon zizanioides Nash) grown in hydroponics.

    Science.gov (United States)

    Marcacci, Sylvie; Raventon, Muriel; Ravanel, Patrick; Schwitzguébel, Jean-Paul

    2005-01-01

    The resistance mechanism of vetiver (Chrysopogon zizanioides) to atrazine was investigated to evaluate its potential for phytoremediation of environment contaminated with the herbicide. Plants known to metabolise atrazine rely on hydroxylation mediated by benzoxazinones, conjugation catalyzed by glutathione-S-transferases and dealkylation probably mediated by cytochromes P450. All three possibilities were explored in mature vetiver grown in hydroponics during this research project. Here we report on the chemical role of benzoxazinones in the transformation of atrazine. Fresh vetiver roots and leaves were cut to extract and study their content in benzoxazinones known to hydroxylate atrazine, such as 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (DIBOA), 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA) and their mono- and di-glucosylated forms. Identification of benzoxazinones was performed by thin layer chromatography (TLC) and comparison of retention factors (Rf) and UV spectra with standards: although some products exhibited the same Rf as standards, UV spectra were different. Furthermore, in vitro hydroxylation of atrazine could not be detected in the presence of vetiver extracts. Finally, vetiver organs exposed to [14C]-atrazine did not produce any significant amount of hydroxylated products, such as hydroxyatrazine (HATR), hydroxy-deethylatrazine (HDEA), and hydroxy-deisopropylatrazine (HDIA). Altogether, these metabolic features suggest that hydroxylation was not a major metabolic pathway of atrazine in vetiver.

  15. Long-term impact of sublethal atrazine perturbs the redox homeostasis in pea (Pisum sativum L.) plants.

    Science.gov (United States)

    Ivanov, Sergei; Shopova, Elena; Kerchev, Pavel; Sergiev, Iskren; Miteva, Lyuba; Polizoev, Djovani; Alexieva, Vera

    2013-02-01

    Atrazine frequently contaminates soil, groundwater, rivers, and ponds. It is well know that acute doses (1-5 mM) of atrazine induce massive generation of singlet oxygen by blocking photosystem II. The sublethal concentrations of this herbicide, similar to those found in the environment, also reduce growth and disrupt photosynthesis in a long-term aspect, but exact mechanisms remain much uncertain. In this study the effects of environmentally relevant atrazine levels, ranging from 0.1 to 10 μM, on pea plants were characterized for up to 20 days. The plants exposed to continuous influence of atrazine exhibited perturbed redox homeostasis with increases of the lipid peroxides, the total and oxidized glutathione pools and elevated guaiacol peroxidase and glutathione-S-transferase activities. In contrast, the long-term atrazine impact did not affect superoxide dismutase activity whereas the catalase was inhibited. The perturbations of the redox status and the recruitment of the antioxidant machinery imply that the sublethal atrazine concentrations alter the poise between production and scavenging of reactive oxygen species. Taken together these results show that the long-term impact of sublethal atrazine has hallmarks of oxidative stress most probably triggered by generation of singlet oxygen.

  16. Impact of soil primary size fractions on sorption and desorption of atrazine on organo-mineral fractions.

    Science.gov (United States)

    Huang, Yufen; Liu, Zhongzhen; He, Yan; Li, Yanliang

    2015-03-01

    In the current study, a mechanical dispersion method was employed to separate clay (fraction in six bulk soils. Batch equilibrium method was used to conduct atrazine sorption and desorption experiments on soil organo-mineral fractions with bulk soils and their contrasting size fractions separately. The potential contribution of total organic carbon (TOC) for atrazine retention in different fractions was further investigated. It was found that clay fraction had the highest adsorption but the least desorption capacities for atrazine, while sand fraction had the lowest adsorption but the highest desorption capacities for atrazine. The adsorption percentage of atrazine, as compared with adsorption by the corresponding bulk soils, ranged from 53.6 to 80.5%, 35.7 to 56.4%, and 0.2 to 4.5% on the clay, silt, and sand fractions, respectively. TOC was one of the key factors affecting atrazine retention in soils, with the exact contribution dependent on varying degree of coating with mineral component in different soil size fractions. The current study may be useful to predict the bioavailability of atrazine in different soil size fractions.

  17. New procedures for simultaneous determination of mesotrione and atrazine in water and soil. Comparison of the degradation processes of mesotrione and atrazine.

    Science.gov (United States)

    Barchanska, Hanna; Rusek, Małgorzata; Szatkowska, Anna

    2012-01-01

    A method for the determination of residues of mesotrione, atrazine and its degradation products: deethylatrazine, hydroxyatrazine, deisopropylatrazine, desethyldesisopropylatrazine in a variety of water and soil matrices has been developed. Mesotrione is a new selective herbicide for use in corn, which has been substituted for atrazine, which has been banned in European Union countries since 2007. Although atrazine has not been used for three vegetative periods, it is still detected in the environment. The analysis was conducted by means of ultra-high-pressure liquid chromatography with ultraviolet detection and liquid chromatography with diode array detection. The procedures for analyte separation from water and soil matrices were also established. The optimal conditions for solid-phase extraction (SPE) were determined. The recoveries were compared with that obtained by means of SPE. Method fortification recoveries from water samples averaged 78-97% and for soil 80-97% depending on the analyte and type of sample. The limits of detection were 0.04-0.61 μg/L for water samples and for soil samples 0.02-0.88 μg/g. The soil samples were collected in spring 2009 from three different fields with water samples being made from effluents from these fields. Samples collection was conducted in the day of mesotrione (Callisto 100SC) application and then done weekly, until the mesotrione concentration was below the limit of quantification. The results enabled the monitoring of mesotrione degradation in soil and its permeability into surface waters; simultaneously, the same studies were conducted for atrazine.

  18. Evaluation of the agronomic performance of atrazine-tolerant transgenic japonica rice parental lines for utilization in hybrid seed production.

    Science.gov (United States)

    Zhang, Luhua; Chen, Haiwei; Li, Yanlan; Li, Yanan; Wang, Shengjun; Su, Jinping; Liu, Xuejun; Chen, Defu; Chen, Xiwen

    2014-01-01

    Currently, the purity of hybrid seed is a crucial limiting factor when developing hybrid japonica rice (Oryza sativa L.). To chemically control hybrid seed purity, we transferred an improved atrazine chlorohydrolase gene (atzA) from Pseudomonas ADP into hybrid japonica parental lines (two maintainers, one restorer), and Nipponbare, by using Agrobacterium-mediated transformation. We subsequently selected several transgenic lines from each genotype by using PCR, RT-PCR, and germination analysis. In the presence of the investigated atrazine concentrations, particularly 150 µM atrazine, almost all of the transgenic lines produced significantly larger seedlings, with similar or higher germination percentages, than did the respective controls. Although the seedlings of transgenic lines were taller and gained more root biomass compared to the respective control plants, their growth was nevertheless inhibited by atrazine treatment compared to that without treatment. When grown in soil containing 2 mg/kg or 5 mg/kg atrazine, the transgenic lines were taller, and had higher total chlorophyll contents than did the respective controls; moreover, three of the strongest transgenic lines completely recovered after 45 days of growth. After treatment with 2 mg/kg or 5 mg/kg of atrazine, the atrazine residue remaining in the soil was 2.9-7.0% or 0.8-8.7% respectively, for transgenic lines, and 44.0-59.2% or 28.1-30.8%, respectively, for control plants. Spraying plants at the vegetative growth stage with 0.15% atrazine effectively killed control plants, but not transgenic lines. Our results indicate that transgenic atzA rice plants show tolerance to atrazine, and may be used as parental lines in future hybrid seed production.

  19. Evaluation of the agronomic performance of atrazine-tolerant transgenic japonica rice parental lines for utilization in hybrid seed production.

    Directory of Open Access Journals (Sweden)

    Luhua Zhang

    Full Text Available Currently, the purity of hybrid seed is a crucial limiting factor when developing hybrid japonica rice (Oryza sativa L.. To chemically control hybrid seed purity, we transferred an improved atrazine chlorohydrolase gene (atzA from Pseudomonas ADP into hybrid japonica parental lines (two maintainers, one restorer, and Nipponbare, by using Agrobacterium-mediated transformation. We subsequently selected several transgenic lines from each genotype by using PCR, RT-PCR, and germination analysis. In the presence of the investigated atrazine concentrations, particularly 150 µM atrazine, almost all of the transgenic lines produced significantly larger seedlings, with similar or higher germination percentages, than did the respective controls. Although the seedlings of transgenic lines were taller and gained more root biomass compared to the respective control plants, their growth was nevertheless inhibited by atrazine treatment compared to that without treatment. When grown in soil containing 2 mg/kg or 5 mg/kg atrazine, the transgenic lines were taller, and had higher total chlorophyll contents than did the respective controls; moreover, three of the strongest transgenic lines completely recovered after 45 days of growth. After treatment with 2 mg/kg or 5 mg/kg of atrazine, the atrazine residue remaining in the soil was 2.9-7.0% or 0.8-8.7% respectively, for transgenic lines, and 44.0-59.2% or 28.1-30.8%, respectively, for control plants. Spraying plants at the vegetative growth stage with 0.15% atrazine effectively killed control plants, but not transgenic lines. Our results indicate that transgenic atzA rice plants show tolerance to atrazine, and may be used as parental lines in future hybrid seed production.

  20. Microscopic examination on cytological changes in Allium cepa and shift in phytoplankton population at different doses of Atrazine

    Science.gov (United States)

    Ghosh, Nabarun; Finger, Kristen; Usnick, Samantha; Rogers, William J.; Das, A. B.; Smith, Don W.

    2010-06-01

    Atrazine is a wide-range herbicide. For over 50 years, atrazine has been used as a selective broadleaf herbicide in many capacities, from pre-plant to pre-emergence to post-emergence, depending on the crop and application. Currently, 96% of all atrazine used is for commercial applications in fields for the control of broadleaf and grassy weeds in crops such as sorghum, corn, sugarcane, pineapple and for the control of undesirable weeds in rangeland. Many panhandle wells have also detected atrazine in samples taken. The concern for the public is the long-term effect of atrazine with its increasing popularity, and the impact on public health. We investigated the effect of different concentrations of atrazine on Allium cepa (onion), a standard plant test system. We established a control with the Allium bulbs grown on hydroponics culture. Varying concentrations of atrazine was used on the standard plant test system, Allium cepa grown hydroponically. The mitotic indices varied and with higher doses, we observed various chromosomal abnormalities including sticky bridges, early and late separations, and lag chromosomes with higher doses of treatments. In the second part of the experiment, 0.1ppb, 1ppb, 10ppb, and 100ppb concentrations of atrazine were applied to established phytoplankton cultures from the Lake Tanglewood, Texas. Study with a Sedgwick-Rafter counter, a BX-40 Olympus microscope with DP-70 camera revealed a gradual shift in the phytoplankton community from obligatory to facultative autotroph and finally to a parasitic planktonic community. This explains the periodic fish kill in the lakes after applications of atrazine in crop fields.

  1. Atrazine Triggers DNA Damage Response and Induces DNA Double-Strand Breaks in MCF-10A Cells

    Directory of Open Access Journals (Sweden)

    Peixin Huang

    2015-06-01

    Full Text Available Atrazine, a pre-emergent herbicide in the chloro-s-triazine family, has been widely used in crop lands and often detected in agriculture watersheds, which is considered as a potential threat to human health. Although atrazine and its metabolites showed an elevated incidence of mammary tumors in female Sprague–Dawley (SD rats, no molecular evidence was found relevant to its carcinogenesis in humans. This study aims to determine whether atrazine could induce the expression of DNA damage response-related proteins in normal human breast epithelial cells (MCF-10A and to examine the cytotoxicity of atrazine at a molecular level. Our results indicate that a short-term exposure of MCF-10A to an environmentally-detectable concentration of atrazine (0.1 µg/mL significantly increased the expression of tumor necrosis factor receptor-1 (TNFR1 and phosphorylated Rad17 in the cells. Atrazine treatment increased H2AX phosphorylation (γH2AX and the formation of γH2AX foci in the nuclei of MCF-10A cells. Atrazine also sequentially elevated DNA damage checkpoint proteins of ATM- and RAD3-related (ATR, ATRIP and phospho-Chk1, suggesting that atrazine could induce DNA double-strand breaks and trigger the DNA damage response ATR-Chk1 pathway in MCF-10A cells. Further investigations are needed to determine whether atrazine-triggered DNA double-strand breaks and DNA damage response ATR-Chk1 pathway occur in vivo.

  2. Polar Codes

    Science.gov (United States)

    2014-12-01

    QPSK Gaussian channels . .......................................................................... 39 vi 1. INTRODUCTION Forward error correction (FEC...Capacity of BSC. 7 Figure 5. Capacity of AWGN channel . 8 4. INTRODUCTION TO POLAR CODES Polar codes were introduced by E. Arikan in [1]. This paper...Under authority of C. A. Wilgenbusch, Head ISR Division EXECUTIVE SUMMARY This report describes the results of the project “More reliable wireless

  3. Collaborative Simulation Grid: Multiscale Quantum-Mechanical/Classical Atomistic Simulations on Distributed PC Clusters in the US and Japan

    Science.gov (United States)

    Kikuchi, Hideaki; Kalia, Rajiv; Nakano, Aiichiro; Vashishta, Priya; Iyetomi, Hiroshi; Ogata, Shuji; Kouno, Takahisa; Shimojo, Fuyuki; Tsuruta, Kanji; Saini, Subhash; Biegel, Bryan (Technical Monitor)

    2002-01-01

    A multidisciplinary, collaborative simulation has been performed on a Grid of geographically distributed PC clusters. The multiscale simulation approach seamlessly combines i) atomistic simulation backed on the molecular dynamics (MD) method and ii) quantum mechanical (QM) calculation based on the density functional theory (DFT), so that accurate but less scalable computations are performed only where they are needed. The multiscale MD/QM simulation code has been Grid-enabled using i) a modular, additive hybridization scheme, ii) multiple QM clustering, and iii) computation/communication overlapping. The Gridified MD/QM simulation code has been used to study environmental effects of water molecules on fracture in silicon. A preliminary run of the code has achieved a parallel efficiency of 94% on 25 PCs distributed over 3 PC clusters in the US and Japan, and a larger test involving 154 processors on 5 distributed PC clusters is in progress.

  4. Enhanced degradation and soil depth effects on the fate of atrazine and major metabolites in Colorado and Mississippi soils.

    Science.gov (United States)

    Krutz, L Jason; Shaner, Dale L; Zablotowicz, Robert M

    2010-01-01

    The aim of this report is to inform modelers of the differences in atrazine fate between s-triazine-adapted and nonadapted soils as a function of depth in the profile and to recommend atrazine and metabolite input values for pesticide process submodules. The objectives of this study were to estimate the atrazine-mineralizing bacterial population, cumulative atrazine mineralization, atrazine persistence, and metabolite (desethylatrazine [DEA], deisopropylatrazine [DIA], and hydroxyatrazine [HA]) formation and degradation in Colorado and Mississippi s-triazine-adapted and nonadapted soils at three depths (0-5, 5-15, and 15-30 cm). Regardless of depth, the AMBP and cumulative atrazine mineralization was at least 3.8-fold higher in s-triazine-adapted than nonadapted soils. Atrazine half-life (T1/2) values pooled over nonadapted soils and depths approximated historic estimates (T1/2 = 60 d). Atrazine persistence in all depths of s-triazine-adapted soils was at least fourfold lower than that of the nonadapted soil. Atrazine metabolite concentrations were lower in s-triazine-adapted than in nonadapted soil by 35 d after incubation regardless of depth. Results indicate that (i) reasonable fate and transport modeling of atrazine will require identifying if soils are adapted to s-triazine herbicides. For example, our data confirm the 60-d T1/2 for atrazine in nonadapted soils, but a default input value of 6 d for atrazine is required for s-triazine adapted soils. (ii) Literature estimates for DEA, DIA, and HA T1/2 values in nonadapted soils are 52, 36, and 60 d, respectively, whereas our analysis indicates that reasonable T1/2 values for s-triazine-adapted soils are 10 d for DEA, 8 d for DIA, and 6 d for HA. (iii) An estimate for the relative distribution of DIA, DEA, and HA produced in nonadapted soils is 18, 72, and 10% of parent, respectively. In s-triazine-adapted soils, the values were 6, 23, and 71% for DIA, DEA, and HA, respectively. The effects of soil adaptation on

  5. Atrazine degradation and enzyme activities in an agricultural soil under two tillage systems.

    Science.gov (United States)

    Mahía, Jorge; Martín, Angela; Carballas, Tarsy; Díaz-Raviña, Montserrat

    2007-05-25

    The content of atrazine and its metabolites (hydroxyatrazine, deethylatrazine and deisopropylatrazine) as well as the activities of two soil enzymes (urease and beta-glucosidase) were evaluated in an acid agricultural soil, located in a temperate humid zone (Galicia, NW Spain), with an annual ryegrass-maize rotation under conventional tillage (CT) and no tillage (NT). Samples were collected during two consecutive years from the arable layer at two depths (0-5 cm and 5-20 cm) and different times after atrazine application. Hydroxyatrazine and deisopropylatrazine were the main metabolites resulting from atrazine degradation in the acid soil studied, the highest levels being detected in the surface layer of the NT treatment. A residual effect of atrazine was observed since hydroxyatrazine was detected in the arable layer (0-5 cm, 5-20 cm) even one year after the herbicide application. Soil enzyme activities in the upper 5 cm layer under NT were consistently higher than those in the same layer under CT. Urease and beta-glucosidase activities decreased with depth in the profile under NT but they did not show any differences between the two depths for the plots under CT. For both tillage systems enzyme activities also reflected temporal changes during the maize cultivation; however, no consistent effect of the herbicide application was observed.

  6. IMMUNOASSAY METHODS FOR MEASURING ATRAZINE AND 3,5,6-TRICHLORO-2-PYRIDINOL IN FOODS

    Science.gov (United States)

    This chapter describes the use of enzyme-linked immunosorbent assay (ELISA) methods for the analysis of two potential environmental contaminants in food sample media, atrazine and 3,5,6-trichloro-2-pyridinol (3,5,6-TCP). Two different immunoassay formats are employed: a magnetic...

  7. Induction of micronuclei and nuclear lesions in Channa punctatus following exposure to carbosulfan, glyphosate and atrazine.

    Science.gov (United States)

    Nwani, Christopher Didigwu; Nagpure, Naresh Sahebrao; Kumar, Ravindra; Kushwaha, Basdeo; Kumar, Pavan; Lakra, Wazir Singh

    2014-10-01

    The genotoxic effects of commonly used agricultural pesticides viz., carbosulfan, glyphosate, and atrazine, were evaluated in Channa punctatus (Pisces, Perciformes) using micronucleus (MN) test and induction of nuclear lesions (NL). The 96 h LC50 value were estimated by probit analysis as 0.27, 32.0 and 42.0 mg L(-1), respectively, for carbosulfan, glyphosate, and atrazine using semi-static bioassays. Based on these values, three sublethal test concentrations of carbosulfan (0.07, 0.13, 0.20 mg L(-1)), glyphosate (8.1, 16.3, 24.4 mg L(-1)) and atrazine (10.6, 21.2, 31.8 mg L(-1)) corresponding to ¼, ½ and ¾ of the LC50 of the pesticides respectively, were selected for exposure for 96 h. Peripheral blood samplings were taken at intervals of 24 h for assessment of MN and NL frequencies. Considerably higher genotoxic damage was induced by carbosulfan as compared to glyphosate and atrazine. There were significant effects (p < 0.01) of concentrations in all the treated groups. The induction of MN and NL was highest at 96 h pesticide exposure at all test concentrations. The nuclear abnormalities recorded in this study, such as blebbed-, lobed-, notched- and bi-nuclei, other than micronuclei, are indicators of genotoxic damage.

  8. Exposure to atrazine and selected non-persistent pesticides among corn farmers during a growing season.

    NARCIS (Netherlands)

    Bakke, B.; de Roos, A.J.; Barr, D.B.; Stewart, P.A.; Blair, A.; Freeman, L.B.; Lynch, C.F.; Allen, R.H.; Alavanja, M.C.; Vermeulen, R.C.H.

    2009-01-01

    The aim was to develop quantitative estimates of farmers' pesticide exposure to atrazine and to provide an overview of background levels of selected non-persistent pesticides among corn farmers in a longitudinal molecular epidemiologic study. The study population consisted of 30 Agricultural Health

  9. Toxicity of atrazine, glyphosate, and quinclorac in bullfrog tadpoles exposed to concentrations below legal limits.

    Science.gov (United States)

    Dornelles, M F; Oliveira, G T

    2016-01-01

    This work sought to ascertain survival and possible changes in levels of glycogen, triglycerides, total lipids, cholesterol, protein, and lipid peroxidation in gills, liver, and muscle of bullfrog tadpoles (Lithobates catesbeianus) exposed to low concentrations of atrazine (2.5 μg L(-1)), glyphosate (18 μg L(-1)), and quinclorac (0.025 μg L(-1)) at laboratorial conditions. Tadpoles showed a reduction of glycogen and triglyceride in all organs and an increase in lipid peroxidation (LPO) compared with control animals. Total lipid in gills and muscle increased in exposure to atrazine, and gills alone in exposure to glyphosate, but decreased in gills, liver, and muscle after quinclorac. Cholesterol increased in gills and liver after atrazine, in gills and muscle after glyphosate, and decreased in liver after quinclorac. Total protein in gills decreased after exposure to all herbicides, increased in muscle after atrazine, and in liver and muscle after quinclorac. These findings show that at concentrations of these herbicides tested can lead to an increase in energy expenditure to maintain homeostasis and survival of these animals despite the increase in lipid peroxidation levels in all organs analyzed. Responses observed can be one of the factors responsible for the decline in the number of amphibians around the world.

  10. Species-dependent effects of biochar amendment on bioaccumulation of atrazine in earthworms.

    Science.gov (United States)

    Wang, Fang; Ji, Rong; Jiang, Zhongwei; Chen, Wei

    2014-03-01

    We observed that at a contamination level of 4.25 mg-atrazine/kg-soil, the biota-soil accumulation factor (BSAF) for the anecic M. guillelmi is approximately 5 times that for the epigeic E. foetida. This is attributable to the fact that bio-uptake by E. foetida is mainly through dermal absorption, whereas bio-uptake by M. guillelmi is largely affected by the gut processes, through which the physical grinding and surfactant-like materials facilitate the desorption of atrazine from soil. Strikingly, biochar amendment resulted in much greater reduction in BSAF for M. guillelmi than for E. foetida. At a biochar dose of 0.5% (wt:wt) the difference in BSAF between the two species became much smaller, and at a dose of 2% no statistical difference was observed. A likely explanation is that gut processes by M. guillelmi were much less effective in extracting atrazine from the biochar (the predominant phase wherein atrazine resided) than from soil particles.

  11. Dynamic speciation analysis of atrazine in aqueous latex nanoparticle dispersions using solid phase microextraction (SPME)

    NARCIS (Netherlands)

    Benhabib, K.; Town, R.M.; Leeuwen, van H.P.

    2009-01-01

    Solid phase microextraction (SPME) is applied in the dynamic speciation analysis of the pesticide atrazine in an aqueous medium containing sorbing latex nanoparticles. It is found that the overall rate of extraction of the analyte is faster than in the absence of nanoparticles and governed by the co

  12. A collection of glycosyltransferases from rice (Oryza sativa) exposed to atrazine.

    Science.gov (United States)

    Lu, Yi Chen; Yang, Sheng Ning; Zhang, Jing Jing; Zhang, Jia Jun; Tan, Li Rong; Yang, Hong

    2013-12-01

    The rice (Oryza sativa) GTs belong to a super family possibly with hundreds of members. However, which GTs are involved in plant response to toxic chemicals is unknown. Here, we demonstrated 59 novel GT genes screened from our recent genome-wide sequencing datasets of rice crops exposed to atrazine (a herbicide persistent in ecosystems). Analysis of GT genes showed that most of the GTs contain functional domains typically found in proteins transferring glycosyl moieties to their target compounds. A phylogenetic analysis revealed that many GT genes from different families have diverse cis-elements necessary for response to biotic and environmental stresses. Experimental validation for the GTs was undertaken through a microarray, and 36 GT genes were significantly detected with an expression pattern similar to that from deep-sequencing datasets. Furthermore, 12 GT genes were randomly selected and confirmed by quantitative real-time RT-PCR. Finally, the special activity of total GTs was determined in rice roots and shoots, with an increased activity under the atrazine exposure. This response was closely associated with atrazine absorption in the rice tissues. These results indicate that exposure to atrazine can trigger specific GT genes and enzyme activities in rice.

  13. Proposed Methodology for Specifying Atrazine Levels of Concern for Protection of Plant Communities in Freshwater Ecosystems

    Science.gov (United States)

    This document describes a proposed methodology for setting levels of concern (LOCs) for atrazine in natural freshwater systems to prevent unacceptably adverse effects on the aquatic plant communities in those systems. LOCs regarding effects on humans and possible effects on amph...

  14. Enhanced atrazine adsorption from aqueous solution using chitosan-modified sepiolite

    Institute of Scientific and Technical Information of China (English)

    刘海成; 陈卫; 崔彪; 刘成

    2015-01-01

    A novel clay mineral biocomposite, chitosan-modified sepiolite (CMSEP), was prepared and used as adsorbent to remove atrazine from water. The adsorption behaviors including thermodynamic and kinetic parameters, effect factors and mechanisms of atrazine adsorption on CMSEP were studied. The results show that the adsorption capacity of atrazine on CMSEP increases with increasing temperature. Protonation of chitosan in biocomposite can improve adsorption ability of the composite to a certain extent. The parametersΔGΘ,ΔHΘ andΔSΘ are−1.48-−2.69 kJ/mol, 7.54 kJ/mol and 30.28 J/mol, respectively. Langmuir isotherm is proved to describe the adsorption data better than other isotherms with a maximum adsorption capacity of 17.92 mg/g, suggesting that the adsorption process is homogeneous. Pseudo-second-order kinetic model can fit the adsorption kinetic processes well although intraparticle diffusion can not be discarded. Briefly, CMSEP has potential value in the removal of atrazine from water and wastewater.

  15. Atrazine adsorption removal with nylon6/polypyrrole core-shell nanofibers mat: possible mechanism and characteristics

    Science.gov (United States)

    Yang, Bi-Yi; Cao, Yang; Qi, Fei-Fei; Li, Xiao-Qing; Xu, Qian

    2015-05-01

    A functionalized nylon6/polypyrrole core-shell nanofibers mat (PA6/PPy NFM) was prepared via situ polymerization on nylon6 electrospun nanofibers mat (PA6 NFM) template and used as an adsorbent to remove atrazine from aqueous solutions. The core-shell structure of PA6/PPy NFM can be clearly proved under scanning electron microscope (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The effects of initial solution pH and ionic strength, as well as the comparison of the adsorption capacity of functionalized (PA6/PPy NFM) and non-functionalized (PA6 NFM) adsorbent, were examined to reveal the possible adsorption mechanism. The results indicated that π-π interaction and electrostatic interaction should play a key role in the adsorption process. The kinetics and thermodynamics studies also further elucidated the detailed adsorption characteristics of atrazine removal by PA6/PPy NFM. The adsorption of atrazine could be well described by the pseudo-second-order equation. The adsorption equilibrium data was well fitted with the Freundlich isotherm model with a maximum adsorption capacity value of 14.8 mg/g. In addition, the increase of adsorption rate caused by a temperature increase could be felicitously explained by the endothermic reaction. The desorption results showed that the adsorption capacity remained almost unchanged after six adsorption/desorption cycles. These results suggest that PA6/PPy NFM could be employed as an efficient adsorbent for removing atrazine from contaminated water sources.

  16. Periphyton responses to nutrient and atrazine mixtures introduced through agricultural runoff

    Science.gov (United States)

    Agricultural runoff often contains pollutants with potential antagonistic impacts on periphyton, such as nutrients and atrazine. The individual influence of these pollutants on periphyton has been extensively studied, but their impact when introduced in a more realistic scenario of multiple agricult...

  17. Enhanced atrazine adsorption from aqueous solution using chitosan-modified sepiolite

    Institute of Scientific and Technical Information of China (English)

    刘海成; 陈卫; 崔彪; 刘成

    2015-01-01

    A novel clay mineral biocomposite, chitosan-modified sepiolite(CMSEP), was prepared and used as adsorbent to remove atrazine from water. The adsorption behaviors including thermodynamic and kinetic parameters, effect factors and mechanisms of atrazine adsorption on CMSEP were studied. The results show that the adsorption capacity of atrazine on CMSEP increases with increasing temperature. Protonation of chitosan in biocomposite can improve adsorption ability of the composite to a certain extent. The parameters ΔGΘ, ΔHΘ and ΔSΘ are-1.48--2.69 k J/mol, 7.54 k J/mol and 30.28 J/mol, respectively. Langmuir isotherm is proved to describe the adsorption data better than other isotherms with a maximum adsorption capacity of 17.92 mg/g, suggesting that the adsorption process is homogeneous. Pseudo-second-order kinetic model can fit the adsorption kinetic processes well although intraparticle diffusion can not be discarded. Briefly, CMSEP has potential value in the removal of atrazine from water and wastewater.

  18. EFFECT OF ATRAZINE ON IMPLANTATION AND EARLY PREGNANCY IN FOUR STRAINS OF RATS

    Science.gov (United States)

    Atrazine (ATR) is an herbicide that has been shown to have adverse reproductive effects including alterations in levels of pituitary hormones such as prolactin (prl) and luteinizing hormone (LH). Since prl's action to promote progesterone secretion is essential for the initiatio...

  19. Kriging Models Predicting Atrazine Concentrations in Surface Water Draining Agricultural Watersheds.

    Science.gov (United States)

    Mosquin, Paul L; Aldworth, Jeremy; Chen, Wenlin

    2016-09-01

    The performance of kriging methods in predicting maximum m-day (m = 1, 7, 14, or 30) rolling averages of atrazine concentrations in 42 site-years of Midwest Corn Belt watersheds under two systematic sampling designs (sampling every 7 or 14 d) was examined. Daily atrazine monitoring data obtained from the Atrazine Ecological Monitoring Program in the Corn Belt region (2009-2014) were used in the evaluation. Both ordinary and universal kriging methods were considered, with the covariate for universal kriging derived from the deterministic Pesticide Root Zone Model (PRZM). For the maximum 1-d rolling averages, prediction did not differ among methods. For rolling averages of longer duration (m > 1), predictions obtained by linear interpolation on a logarithmic scale were better (up to 15% lower for 7-d sampling and 22% lower for 14-d sampling in terms of the relative root mean squared prediction error) than those obtained by linear interpolation on the original linear scale and also less variable. For kriging methods, empirical semivariograms of daily atrazine time series suggest a negligible noise process, supported by replicate analysis of selected field samples; piecewise linear semivariogram models were found to perform best for predicting sampled data. We demonstrate that kriging prediction intervals offer close to nominal coverage for unsampled values.

  20. The herbicide atrazine induces hyperactivity and compromises tadpole detection of predator chemical cues.

    Science.gov (United States)

    Ehrsam, Mackenzie; Knutie, Sarah A; Rohr, Jason R

    2016-09-01

    The ability to detect chemical cues is often critical for freshwater organisms to avoid predation and find food and mates. In particular, reduced activity and avoidance of chemical cues signaling predation risk are generally adaptive behaviors that reduce prey encounter rates with predators. The present study examined the effects of the common herbicide atrazine on the ability of Cuban tree frog (Osteopilus septentrionalis) tadpoles to detect and respond to chemical cues from larval dragonfly (Libellulidae sp.) predators. Tadpoles exposed to an estimated environmental concentration of atrazine (calculated using US Environmental Protection Agency software; measured concentration, 178 μg/L) were significantly hyperactive relative to those exposed to solvent control. In addition, control tadpoles significantly avoided predator chemical cues, but tadpoles exposed to atrazine did not. These results are consistent with previous studies that have demonstrated that ecologically relevant concentrations of atrazine can induce hyperactivity and impair the olfactory abilities of other freshwater vertebrates. The authors call for additional studies examining the role of chemical contaminants in disrupting chemical communication and the quantification of subsequent impacts on the fitness and population dynamics of wildlife. Environ Toxicol Chem 2016;35:2239-2244. © 2016 SETAC.

  1. MATERNAL ATRAZINE (ATR) ALTERS HYPOTHALAMIC DOPAMINE (HYP-DA) AND SERUM PROLACTIN (SPRL) IN MALE PUPS

    Science.gov (United States)

    Maternal Atrazine (ATR) alters hypothalamic dopamine (HYP-DA) and serum prolactin (sPRL) in male pups. 1Christopher Langdale, 2Tammy Stoker and 2Ralph Cooper. 1 Dept. of Cell Biology, North Carolina State University College of Veterinary Medicine, Raleigh, NC. 2 Endocrinology ...

  2. Inlfuence of Soil pH and Temperature on Atrazine Bioremediation

    Institute of Scientific and Technical Information of China (English)

    Shahla Andleeb; Zhao Jiang; Khalil ur Rehman; Erinle Kehinda Olajide; Zhang Ying

    2016-01-01

    Present study was conducted to clarify soil pH and temperature influence on different atrazine bioremediation techniques. For this purpose, sodium citrate,Arthrobactorsp. strain DNS10, sawdust and animal manure were selected to clarify their atrazine remediation efficiency under pH 5, 7 and 9 and temperatures 20, 30 and 40℃, respectively. Results showed that atrazine remediation was generally optimized at pH 7 and 30℃ for all the treatments except sodium citrate as soil treated with sawdust was not temperature dependant, but at pH 5 remediation process was determined slower. Atrazine remediation in soil with no additional amendment was only 34%, while in soil treated with sawdust, DNS10, sodium citrate and animal manure were 75.17%, 89%, 74.17% and 76.83% at optimized pH and temperature. Overall atazine removal rate was significantly (≥0.01) higher with increasing in temperature at all the selected pH.

  3. The impact of atrazine on lake periphyton communities, including carbon uptake dynamics using track autoradiography.

    Science.gov (United States)

    Hamilton, P B; Jackson, G S; Kaushik, N K; Solomon, K R

    1987-01-01

    Chlorophyll a, freshweight biomass, ash-free dry weight, cell numbers, species richness, community carbon uptake and species-specific carbon uptake were used to monitor the impact of atrazine (2 chloro-4-ethylamino-6-isopropylamino-s-triazine) on an in situ, enclosed periphyton community. Atrazine concentrations ranging from 0.08 to 1.56 mg litre(-1) were used during the 2 years of study. In both 1982 and 1983, there was a shift from a chlorophyte- to a diatom-dominated community. In 1982 the cyanobacterium Cylindrospermum stagnale and the chlorophyte Tetraspora cylindrica developed isolated colonies in the 1.56 mg litre(-1) treatment, indicating resistance to atrazine at this concentration. After atrazine exposure, community productivity was reduced by 21% to 82% in the low to high exposures, respectively. After day 21 productivity returned to control levels. It was shown, using track autoradiography, that the productivities of the larger algae Mougeotia sp., Oedogonium sp., Tolypothrix limbata and Epithemia turgida were the most affected, with reductions of 74.3% to 93.1% that of the controls. All the biotic measures indicated reduced growth after herbicide exposure.

  4. Found a USB stick? Go and infect your PC!

    CERN Document Server

    Computer Security Team

    2012-01-01

    Err. Wait. Please no! USB sticks are not innocent little things. They can quickly mutate into malicious nasty beasts! Just in the recent past, at least two physics experiments were suffering as their control and data acquisition PCs, respectively, were infected by USB sticks holding malicious code. A bit longer ago, a series of laptops were infected at a 2008 computing conference as an infected USB stick made its tour around. Bad luck for those who ran a Windows operating system and inserted that stick…   So, you found a USB stick in the cafeteria? Take care. If this were a lollipop, you wouldn’t just pick it up and lick it, would you? So beware of USB sticks whose origin or previous usage you don’t know. They might infect your PC once plugged in. In order to be on the safe side, accept and share only USB sticks whose owner you trust. Run up-to-date anti-virus software on your PC, make sure that its operating system is patched...

  5. Peak Pc Prediction in Conjunction Analysis: Conjunction Assessment Risk Analysis. Pc Behavior Prediction Models

    Science.gov (United States)

    Vallejo, J.J.; Hejduk, M.D.; Stamey, J. D.

    2015-01-01

    Satellite conjunction risk typically evaluated through the probability of collision (Pc). Considers both conjunction geometry and uncertainties in both state estimates. Conjunction events initially discovered through Joint Space Operations Center (JSpOC) screenings, usually seven days before Time of Closest Approach (TCA). However, JSpOC continues to track objects and issue conjunction updates. Changes in state estimate and reduced propagation time cause Pc to change as event develops. These changes a combination of potentially predictable development and unpredictable changes in state estimate covariance. Operationally useful datum: the peak Pc. If it can reasonably be inferred that the peak Pc value has passed, then risk assessment can be conducted against this peak value. If this value is below remediation level, then event intensity can be relaxed. Can the peak Pc location be reasonably predicted?

  6. Study of the Bioremediation of Atrazine under Variable Carbon and Nitrogen Sources by Mixed Bacterial Consortium Isolated from Corn Field Soil in Fars Province of Iran

    Directory of Open Access Journals (Sweden)

    Mansooreh Dehghani

    2013-01-01

    Full Text Available Atrazine herbicide that is widely used in corn production is frequently detected in water resources. The main objectives of this research were focused on assessing the effects of carbon and nitrogen sources on atrazine biodegradation by mixed bacterial consortium and by evaluating the feasibility of using mixed bacterial consortium in soil culture. Shiraz corn field soil with a long history of atrazine application has been explored for their potential of atrazine biodegradation. The influence of different carbon compounds and the effect of nitrogen sources and a different pH (5.5–8.5 on atrazine removal efficiency by mixed bacterial consortium in liquid culture were investigated. Sodium citrate and sucrose had the highest atrazine biodegradation rate (87.22% among different carbon sources. Atrazine biodegradation rate decreased more quickly by the addition of urea (26.76% compared to ammonium nitrate. Based on the data obtained in this study, pH of 7.0 is optimum for atrazine biodegradation. After 30 days of incubation, the percent of atrazine reduction rates were significantly enhanced in the inoculated soils (60.5% as compared to uninoculated control soils (12% at the soil moisture content of 25%. In conclusion, bioaugmentation of soil with mixed bacterial consortium may enhance the rate of atrazine degradation in a highly polluted soil.

  7. Tablet PC Support of Students' Learning Styles

    Directory of Open Access Journals (Sweden)

    Shreya Kothaneth

    2012-12-01

    Full Text Available In the context of rapid technology development, it comes as no surprise that technology continues to impact the educational domain, challenging traditional teaching and learning styles. This study focuses on how students with different learning styles use instructional technology, and in particular, the tablet PC, to enhance their learning experience. The VARK model was chosen as our theoretical framework as we analyzed responses of an online survey, both from a quantitative and qualitative standpoint. Results indicate that if used correctly, the tablet PC can be used across different learning styles to enrich the educational experience.

  8. Atrazine degradation by fungal co-culture enzyme extracts under different soil conditions.

    Science.gov (United States)

    Chan-Cupul, Wilberth; Heredia-Abarca, Gabriela; Rodríguez-Vázquez, Refugio

    2016-01-01

    This investigation was undertaken to determine the atrazine degradation by fungal enzyme extracts (FEEs) in a clay-loam soil microcosm contaminated at field application rate (5 μg g(-1)) and to study the influence of different soil microcosm conditions, including the effect of soil sterilization, water holding capacity, soil pH and type of FEEs used in atrazine degradation through a 2(4) factorial experimental design. The Trametes maxima-Paecilomyces carneus co-culture extract contained more laccase activity and hydrogen peroxide (H2O2) content (laccase = 18956.0 U mg protein(-1), H2O2 = 6.2 mg L(-1)) than the T. maxima monoculture extract (laccase = 12866.7 U mg protein(-1), H2O2 = 4.0 mg L(-1)). Both extracts were able to degrade atrazine at 100%; however, the T. maxima monoculture extract (0.32 h) achieved a lower half-degradation time than its co-culture with P. carneus (1.2 h). The FEE type (p = 0.03) and soil pH (p = 0.01) significantly affected atrazine degradation. The best degradation rate was achieved by the T. maxima monoculture extract in an acid soil (pH = 4.86). This study demonstrated that both the monoculture extracts of the native strain T. maxima and its co-culture with P. carneus can efficiently and quickly degrade atrazine in clay-loam soils.

  9. Ongoing functional evolution of the bacterial atrazine chlorohydrolase AtzA.

    Science.gov (United States)

    Noor, Sajid; Changey, Frédérique; Oakeshott, John G; Scott, Colin; Martin-Laurent, Fabrice

    2014-02-01

    Triazine herbicides such as atrazine and simazine which were heavily used in the latter half of the twentieth century constituted a rich new source of nitrogen for soil microbes. An atzA dechlorinase active against both atrazine and simazine was isolated from various soil bacteria from diverse locations in the mid 1990s. We have surveyed the atzA genes from eight triazine-degrading Aminobacter aminovorans strains isolated from French agricultural soils recurrently exposed to triazines in 2000. Six amino acid differences from the original isolate were each found in more than one of the A. aminovorans strains. Three of these in particular (V92L, A170T and A296T) were recovered from a majority of the isolates and from locations separated by up to 900 km, so may reflect ongoing selection for the new function. Two of the latter (A170T and A296T) were indeed found to confer higher specificity for simazine, albeit not atrazine, and greater affinity for a metal ion required for activity, than did the original variant. In contrast, we found that ongoing maintenance of the original atzA-containing isolate in laboratory culture for 12 years in a medium containing high concentrations of atrazine has led to the fixation of another amino acid substitution that substantially reduces activity for the triazines. The high concentrations of atrazine in the medium may have relaxed the selection for a highly efficient triazine dechlorinase activity, and that there is some, as yet uncharacterised, counter selection against the activity of this enzyme under these conditions.

  10. Transport of atrazine versus bromide and δO18 in sand

    Science.gov (United States)

    Tindall, James A.; Friedel, Michael J.

    2016-01-01

    The objective of this research was to determine the process of atrazine transport compared to bromide and δO18 transport in sands near Denver. Three 1.5 × 2 × 1.5-m plots were installed and allowed to equilibrate for 2 years before research initiation and were instrumented with 1.5 × 2-m zero-tension pan lysimeters installed at 1.5-m depths. Additionally, each plot was instrumented with suction lysimeters, tensiometers, time domain reflectometry (TDR) moisture probes, and thermocouples (to measure soil temperature) at 15-cm depth increments. All plots were enclosed with a raised frame (of 8-cm height) to prevent surface runoff. During the 2-year period before research began, all suction and pan lysimeters were purged monthly and were sampled for fluids immediately prior to atrazine and KBr application to obtain background concentrations. Atrazine illustrated little movement until after a significant rainfall event, which peaked concentrations at depths of about 90 to 135 cm. Both Br− and δO18 moved rapidly through the soil, probably owing to soil porosity and anion exclusion for Br−. Concentrations of atrazine exceeding 5.0 μL−1 were observed with depth (90 to 150 cm) after several months. It appears that significant rainfall events were a key factor in the movement of atrazine in the sand, which allowed the chemicals to move to greater depths and thus avoid generally found biodegradation processes.

  11. Atrazine affects kidney and adrenal hormones (AHs) related genes expressions of rare minnow (Gobiocypris rarus)

    Energy Technology Data Exchange (ETDEWEB)

    Yang Lihua; Zha Jinmiao; Li Wei; Li Zhaoli [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road 18, P.O. Box 2871, Beijing 100085 (China); Wang Zijian, E-mail: wangzj@rcees.ac.cn [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road 18, P.O. Box 2871, Beijing 100085 (China)

    2010-05-05

    Atrazine, one of the most widely used herbicides, has been proved to interfere with sexual hormones. However few studies have considered the effects of atrazine on adrenal hormones (AH). In this study, rare minnow (Gobiocypris rarus) was exposed to 0, 3, 10, 33, 100 and 333 {mu}g/l atrazine for 28 days. The histopathology of kidney and gill was examined and the expressions of AHs-related genes including Na{sup +},K{sup +}-ATPase, glucocorticoid receptor (gr), heat shock protein 70 (hsp70), and heat shock protein 90 (hsp90) in kidney and gill were quantitatively determined. Histopathological observation revealed obvious lesions in gill including hyperplasia, necrosis in epithelium region, aneurysm and lamellar fusion at concentrations as low as 10 {mu}g/l. The observed lesions in kidney included extensive expansion in the lumen, degenerative and necrotic changes of the tubular epithelia, shrinkage of the glomerulus as well as increase of the Bowman's space at concentrations as low as 10 {mu}g/l. The expressions of Na{sup +},K{sup +}-ATPase, gr, hsp70 and hsp90 in the kidney of females were significantly decreased at all concentrations. For males, the expressions of hsp90 in the kidney of all treated groups were significantly down-regulated, while gr at all concentrations and hsp70 at 10, 33, 100 {mu}g/l were significantly up-regulated. However in the gill, the expressions of these genes were not significantly different from the control. These results indicated that exposure to atrazine caused impairments of kidney and gill of fish at environmental related concentrations. Histopathological lesions could partly attribute to the changes of the expressions of AHs-related genes in kidney. We concluded also that atrazine is a potential AHs-disruptor and AHs-related genes in kidney of fish could be used as sensitive molecular biomarkers.

  12. A comparative study of the modeled effects of atrazine on aquatic plant communities in midwestern streams.

    Science.gov (United States)

    Nair, Shyam K; Bartell, Steven M; Brain, Richard A

    2015-11-01

    Potential effects of atrazine on the nontarget aquatic plants characteristic of lower-order streams in the Midwestern United States were previously assessed using the Comprehensive Aquatic System Model (CASMATZ ). Another similar bioenergetics-based, mechanistic model, AQUATOX, was examined in the present study, with 3 objectives: 1) to develop an AQUATOX model simulation similar to the CASMATZ model reference simulation in describing temporal patterns of biomass production by modeled plant populations, 2) to examine the implications of the different approaches used by the models in deriving plant community-based levels of concern (LOCs) for atrazine, and 3) to determine the feasibility of implementing alternative ecological models to assess ecological impacts of atrazine on lower-order Midwestern streams. The results of the present comparative modeling study demonstrated that a similar reference simulation to that from the CASMATZ model could be developed using the AQUATOX model. It was also determined that development of LOCs and identification of streams with exposures in excess of the LOCs were feasible with the AQUATOX model. Compared with the CASMATZ model results, however, the AQUATOX model consistently produced higher estimates of LOCs and generated non-monotonic variations of atrazine effects with increasing exposures. The results of the present study suggest an opportunity for harmonizing the treatments of toxicity and toxicity parameter estimation in the CASMATZ and the AQUATOX models. Both models appear useful in characterizing the potential impacts of atrazine on nontarget aquatic plant populations in lower-order Midwestern streams. The present model comparison also suggests that, with appropriate parameterization, these process-based models can be used to assess the potential effects of other xenobiotics on stream ecosystems.

  13. Multiple resistance to atrazine and imazethapyr in hairy beggarticks (Bidens pilosa

    Directory of Open Access Journals (Sweden)

    Hudson Kagueyama Takano

    Full Text Available ABSTRACT Resistance to herbicides is a serious threat to crop production worldwide, especially in agronomic crops and cereals. This research evaluated the possible occurrence of Bidens pilosa resistant to imazethapyr and atrazine in Brazil. The resistant biotype was collected from an area with a history of repeated application of photosystem II (PSII and ALS inhibitor herbicides. The susceptible biotype was collected from an area with no history of herbicide application. Resistance verification experiments were carried out in the greenhouse. The treatments were arranged in a 3 x 8 factorial scheme, where the first factor was populations [susceptible (S, parent resistant (PR, and resistant F1 (RF1]; and the second factor was herbicide dose (0, 375, 750, 1500, 3000, 6000, 12000 and 24000 g ha-1 for atrazine; or 0, 12.5, 25, 50, 100, 200, 400 and 800 g ha-1 for imazethapyr. The resistance factor to atrazine was 2.83 for PR and 5.55 for RF1. This population was more resistant to imazethapyr (>21-fold than it was to atrazine. The recommended maximum dose of the herbicides did not control this B. pilosa population adequately. The data support the claim that B. pilosa population from this field in Quarto Centenário, Parana is resistant to two herbicide modes of action - PSII inhibitor (i.e. atrazine and ALS inhibitor (i.e. imazethapyr. This is the first report of such case for this species, globally. Cross-resistance to other ALS inhibitors and other PS II inhibitors as well as the respective mechanisms of resistance to each herbicide are being investigated.

  14. Desain dan Implementasi Sistem Kendali CNC Router Menggunakan PC untuk Flame Cutting Machine

    Directory of Open Access Journals (Sweden)

    Roni Permana Saputra

    2012-03-01

    Full Text Available This paper focuses on design of router control systems based on computer numerical control (CNC using personal computer (PC implemented in flame cutting machine (FCM. NC-Code entered into the computer translated to be a command signal sent by the PC to a microcontroller to control the end effector’s movement alongthe X and Y axis simultaneously based on linear and circular interpolations calculation on the PC. This control system is implemented on FCM by connecting the output control of the microcontroller with the driver actuator of the FCM in the form of a DC motor. The obtained result is in the form of a CNC router control system prototype to be implemented in the FCM which is capable to perform linear interpolation and circular interpolation. 

  15. ATRAZINE INCREASES DIMETHYLBENZ[A]ANTHRACENE-INDUCED MAMMARY TUMOR INCIDENCE IN LONG EVANS OFFSPRING EXPOSED IN UTERO

    Science.gov (United States)

    ATRAZINE INCREASES DIMETHYLBENZ[A]ANTHRACENE-INDUCED MAMMARY TUMOR INCIDENCE IN LONG EVANS OFFSPRING EXPOSED IN UTERO.SE Fenton and CC DavisReproductive Toxicology Division, NHEERL, ORD, USEPA, Durham, NC, USARecently, we found that ATR exposure during ma...

  16. Gestational exposure to atrazine has little effect on female reproductive parameters in Sprague-Dawley (SD) rats

    Science.gov (United States)

    Atrazine (ATR), a commonly used herbicide, has been shown to exert reproductive effects in animals; however, most ofthese studies have focused on adult exposure. In contrast, there is limited information available on the reproductive and developmental effects of gestational expos...

  17. Novel molecular events associated with altered steroidogenesis induced by exposure to atrazine in the intact and castrate male rat

    Science.gov (United States)

    Toxicology is increasingly focused on molecular events comprising adverse outcome pathways. Atrazine activates the hypothalamic-pituitary adrenal axis, but relationships to gonadal alterations are unknown. We characterized hormone profiles and adrenal (intact and castrate) and te...

  18. Histopathological alterations in the kidney of Caspian kutum, Rutilus frisii kutum, larvae and fingerlings exposed to sublethal concentration of atrazine.

    Science.gov (United States)

    Khoshnood, Zahra

    2015-02-01

    The use of chemical pesticides has increased environmental pollution and affected ichthyofauna as non target organisms. In the present study, the histopathological alterations in the larvae and fingerlings of the Caspian kutum, Rutilus frisii kutum, were used as a model to investigate the toxic effects of triazine herbicide, atrazine. To investigate toxic effects of atrazine, fish were exposed to sublethal concentration of ½ LC50 for 96 h. Histologically, the most significant alterations in kidney tissues were hyperplasia, necrosis, vacuolation, swelling, hypertrophy, aggregation of hyaline droplets, and disruption of the haematopitic tissue of the head kidney. The damage was more severe in larvae than the fingerlings. Results showed that alterations in kidney tissue caused by atrazine were not specific but it could be concluded that atrazine is excessively toxic for Caspian kutum even at sublethal concentration and acute exposure.

  19. Evaluation of flow injection analysis method with spectrophotometric detection for the determination of atrazine in soil extracts.

    Science.gov (United States)

    Martins, Elisandra C; Melo, Vander De F; Abate, Gilberto

    2016-09-01

    A method for determining atrazine in soil extracts was evaluated by flow injection analysis with spectrophotometric detection. The method is based on the reaction of atrazine with pyridine in an acid medium followed by the reaction with NaOH and sulfanilic acid. Several analytical conditions were previously studied and optimized. Under the best conditions of analysis, the limits of detection and quantification were 0.15 and 0.45 mg L(-1), respectively, for a linear response between 0.50 and 2.50 mg L(-1), and a sampling throughput of 21 determinations per hour. Using the standard addition method, the maximum relative standard deviation of 17% and recovery values between 80 and 100% were observed for three extracts from soil samples with different composition. The proposed method is simple, low-cost and easy to use, and can be employed for studies involving atrazine in soil samples or for screening of atrazine in soils.

  20. Assessment of selenium and atrazine exposure and effects to wildlife at the North Platte National Wildlife Refuge, Scottsbluff, Nebraska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This study evaluated selenium and atrazine exposure and effects to fish and wildlife at North Platte National Wildlife Refuge (Refuge) in Scotts Bluff County,...

  1. New unifying procedure for PC index calculations.

    Science.gov (United States)

    Stauning, P.

    2012-04-01

    The Polar Cap (PC) index is a controversial topic within the IAGA scientific community. Since 1997 discussions of the validity of the index to be endorsed as an official IAGA index have ensued. Currently, there are now the three separate PC index versions constructed from the different procedures used at the three institutes: the Arctic and Antarctic Research Institute (AARI), the Danish Meteorological Institute (DMI), and the Danish National Space Institute (DTU Space). It is demonstrated in this presentation, that two consistent unifying procedures can be built from the best elements of the three different versions. One procedure uses a set of coefficients aimed at the calculation of final PC index values to be accepted by IAGA. The other procedure uses coefficients aimed at on-line real-time production of preliminary PC index values for Space Weather monitoring applications. For each of the two cases the same procedure is used for the northern (PCN) and the southern (PCS) polar cap indices, and the derived PCN and PCS coefficients are similar.

  2. An Automation Interface for Kappa PC

    DEFF Research Database (Denmark)

    Hartvig, Susanne C

    1999-01-01

    The reports documents an automation interface for Kappa PC. The automation interface can be used to embed Kappa applications in 32-bit Windowsapplications.The interface includes functions for initialising Kappa, for loading an application, for settingvalues, for getting values, and for stopping...

  3. The effect of chars and their water extractable organic carbon (WEOC) fractions on atrazine adsorption-desorption processes

    Science.gov (United States)

    Cavoski, I.; Jablonowski, N.; Burauel, P.; Miano, T.

    2012-04-01

    Chars are carbonaceous material produced from different type of biomass by pyrolysis. They are known as highly effective adsorbents for atrazine therefore limiting its degradation and its diffusion into the aqueous phase. The aim of the present work is to study the effects of different chars and char's derived WEOC on atrazine sorption-desorption processes. The five chars been used in this study derived from: 1) fast pyrolysis from hard wood (FP1); 2) flash pyrolysis from soft wood (FP2); 3) slow pyrolysis from deciduous wood (CC); 4) gasification from deciduous wood (GC) and 5) the market, purchased as activated charcoal standard (AC). Short-term batch equilibration tests were conducted to assess the sorption-desorption behavior of 14C-labeled atrazine on the chars, with a special focus on the desorption behavior using successive dilution method with six consecutive desorption step. Chars and their WEOC were physically and chemically characterized. Results demonstrate that biomass and pyrolysis process used to produce chars affect their physical and chemical properties, and atrazine adsorption-desorption behavior. Atrazine desorption resulted from the positive and competitive interactions between WEOC and chars surfaces. WEOC pool play important role in atrazine adsorption-desorption behavior. FP1 and FP2 with higher concentration of WEOC showed higher desorption rates, whereas GC, CC and AC with insignificant WEOC concentration strongly adsorb atrazine with low desorption rates. According to our results, when high WEOC pools chars are concerned, an increase in atrazine desorption can be observed but further studies would help in confirming the present results.

  4. Fast detection of covert visuospatial attention using hybrid N2pc and SSVEP features

    Science.gov (United States)

    Xu, Minpeng; Wang, Yijun; Nakanishi, Masaki; Wang, Yu-Te; Qi, Hongzhi; Jung, Tzyy-Ping; Ming, Dong

    2016-12-01

    Objective. Detecting the shift of covert visuospatial attention (CVSA) is vital for gaze-independent brain-computer interfaces (BCIs), which might be the only communication approach for severely disabled patients who cannot move their eyes. Although previous studies had demonstrated that it is feasible to use CVSA-related electroencephalography (EEG) features to control a BCI system, the communication speed remains very low. This study aims to improve the speed and accuracy of CVSA detection by fusing EEG features of N2pc and steady-state visual evoked potential (SSVEP). Approach. A new paradigm was designed to code the left and right CVSA with the N2pc and SSVEP features, which were then decoded by a classification strategy based on canonical correlation analysis. Eleven subjects were recruited to perform an offline experiment in this study. Temporal waves, amplitudes, and topographies for brain responses related to N2pc and SSVEP were analyzed. The classification accuracy derived from the hybrid EEG features (SSVEP and N2pc) was compared with those using the single EEG features (SSVEP or N2pc). Main results. The N2pc could be significantly enhanced under certain conditions of SSVEP modulations. The hybrid EEG features achieved significantly higher accuracy than the single features. It obtained an average accuracy of 72.9% by using a data length of 400 ms after the attention shift. Moreover, the average accuracy reached ˜80% (peak values above 90%) when using 2 s long data. Significance. The results indicate that the combination of N2pc and SSVEP is effective for fast detection of CVSA. The proposed method could be a promising approach for implementing a gaze-independent BCI.

  5. Speech coding

    Energy Technology Data Exchange (ETDEWEB)

    Ravishankar, C., Hughes Network Systems, Germantown, MD

    1998-05-08

    Speech is the predominant means of communication between human beings and since the invention of the telephone by Alexander Graham Bell in 1876, speech services have remained to be the core service in almost all telecommunication systems. Original analog methods of telephony had the disadvantage of speech signal getting corrupted by noise, cross-talk and distortion Long haul transmissions which use repeaters to compensate for the loss in signal strength on transmission links also increase the associated noise and distortion. On the other hand digital transmission is relatively immune to noise, cross-talk and distortion primarily because of the capability to faithfully regenerate digital signal at each repeater purely based on a binary decision. Hence end-to-end performance of the digital link essentially becomes independent of the length and operating frequency bands of the link Hence from a transmission point of view digital transmission has been the preferred approach due to its higher immunity to noise. The need to carry digital speech became extremely important from a service provision point of view as well. Modem requirements have introduced the need for robust, flexible and secure services that can carry a multitude of signal types (such as voice, data and video) without a fundamental change in infrastructure. Such a requirement could not have been easily met without the advent of digital transmission systems, thereby requiring speech to be coded digitally. The term Speech Coding is often referred to techniques that represent or code speech signals either directly as a waveform or as a set of parameters by analyzing the speech signal. In either case, the codes are transmitted to the distant end where speech is reconstructed or synthesized using the received set of codes. A more generic term that is applicable to these techniques that is often interchangeably used with speech coding is the term voice coding. This term is more generic in the sense that the

  6. Evaluation of potential mechanisms of atrazine-induced reproductive impairment in fathead minnow (Pimephales promelas) and Japanese medaka (Oryzias latipes)

    Science.gov (United States)

    Richter, Cathy; Papoulias, Diana M.; Whyte, Jeffrey J.; Tillitt, Donald E.

    2016-01-01

    Atrazine has been implicated in reproductive dysfunction of exposed organisms, and previous studies documented decreased egg production in Japanese medaka (Oryzias latipes) and fathead minnows (Pimephales promelas) during 30-d to 38-d exposures to 0.5 µg/L, 5 µg/L, and 50 µg/L atrazine. The authors evaluated possible mechanisms underlying the reduction in egg production. Gene expression in steroidogenesis pathways and the hypothalamus–pituitary–gonad axis of male and female fish was measured. Atrazine did not significantly induce gonad aromatase (cyp19a1a) expression. An atrazine-induced shift in the number of females in an active reproductive state was observed. Expression of the egg maturation genes vitellogenin 1 (vtg1) and zona pellucida glycoprotein 3.1 (zp3.1) in medaka females was correlated and had a bimodal distribution. In both species, females with low vtg1 or zp3.1 expression also had low expression of steroidogenesis genes in the gonad, estrogen receptor in the liver, and gonadotropins in the brain. In the medaka, the number of females per tank that had high expression of zp3.1 was significantly correlated with egg production per tank. The number of medaka females with low expression of zp3.1 increased significantly with atrazine exposure. Thus, the decline in egg production observed in response to atrazine exposure may be the result of a coordinated downregulation of genes required for reproduction in a subset of females.

  7. Effects of carbon amendment on in situ atrazine degradation and total microbial biomass.

    Science.gov (United States)

    Ngigi, Anastasiah N; Getenga, Zachary M; Dörfler, Ulrike; Boga, Hamadi I; Kuria, Benson; Ndalut, Paul; Schroll, Reiner

    2013-01-01

    This study elucidates the effects of carbon amendment on metabolic degradation of atrazine (6-chloro-N(2)-ethyl-N(4)-isopropyl-1,3,5-triazine-2,4-diamine) and total microbial biomass in soil. Degradation of (14)C-ring-labelled atrazine was monitored in laboratory incubations of soils supplemented with 0, 10, 100 and 1000 μg g(-1) sucrose concentrations. An experiment to determine the effect of carbon amendment on total microbial biomass and soil respiration was carried out with different concentrations of sucrose and non-labelled atrazine. The soils were incubated at a constant temperature and constant soil moisture at water potential of -15 kPa and a soil density of 1.3 g cm(-3). Mineralization of (14)C-ring-labelled atrazine was monitored continuously over a period of 59 d in the first experiment. The CO(2) production was monitored for 62 d in the second experiment and microbial biomass determined at the end of the incubation period. The addition of 1000 μg g(-1) sucrose reduced atrazine mineralization to 43.5% compared to 51.7% of the applied amount for the treatment without sucrose. The addition of 1000 μg g(-1) sucrose modified the transformation products to 1.08 μg g(-1) deisopropylatrazine (DIA), 0.32 μg g(-1) desethylatrazine (DEA) and 0.18 μg g(-1) deisopropyl-2-hydroxyatrazine (OH-DIA). Treatment without sucrose resulted in formation of 0.64 μg g(-1) hydroxyatrazine (HA), 0.28 μg g(-1) DIA and 0.20 μg g(-1) OH-DIA. Atrazine dealkylation was enhanced in treatments with 100 and 1000 μg g(-1) of sucrose added. HA metabolite was formed in the control (no sucrose) and in the presence of 10 μg g(-1) of sucrose, whereas DEA was only detected in treatment with 1000 μg g(-1) sucrose. Results indicate that total microbial biomass increased significantly (P < 0.001) with the addition of 1000 μg g(-1) sucrose.

  8. Processes controlling the episodic streamwater transport of atrazine and other agrichemicals in an agricultural watershed

    Science.gov (United States)

    Hyer, Kenneth E.; Hornberger, George M.; Herman, Janet S.

    2001-12-01

    Episodic streamwater transport of atrazine (a common agricultural herbicide) and nutrients has been observed throughout agricultural watersheds in the United States and poses a serious threat to the quality of its water resources. Catchment-scale atrazine and nutrient transport processes after agricultural application are still poorly understood, and predicting episodic streamwater composition remains an elusive goal. We instrumented a 1.2-km 2 agricultural catchment near Harrisonburg, Virginia, and examined streamwater, overland flow, soil water, groundwater, and rainfall during the summer of 1998. Storm chemographs demonstrated different patterns for constituents derived primarily from weathering (silica and calcium), compared to constituents derived primarily from early spring land applications (nitrate, atrazine, DOC, potassium, chloride, and sulfate). During storms, the concentrations of silica and calcium decreased, the atrazine response was variable, and the concentrations of nitrate, DOC, potassium, chloride, and sulfate increased; the elevated nitrate signal lagged several hours behind the other elevated constituents. Graphical and statistical analyses indicated a relatively stable spring-fed baseflow was modified by a mixture of overland flow and soil water. A rapid, short-duration overland-flow pulse dominated the streamflow early in the event and contributed most of the potassium, DOC, chloride, suspended sediment, and atrazine. A longer-duration soil-water pulse dominated the streamflow later in the event and contributed the nitrate as well as additional potassium, DOC, sulfate, and atrazine. The contributions to the episodic streamflow were quantified using a flushing model in which overland-flow and soil-water concentrations decreased exponentially with time during an episode. Flushing time constants for the overland-flow and soil-water reservoirs were calculated on a storm-by-storm basis using separate tracers for each time-variable reservoir

  9. Speaking Code

    DEFF Research Database (Denmark)

    Cox, Geoff

    ; alternatives to mainstream development, from performances of the live-coding scene to the organizational forms of commons-based peer production; the democratic promise of social media and their paradoxical role in suppressing political expression; and the market’s emptying out of possibilities for free...... development, Speaking Code unfolds an argument to undermine the distinctions between criticism and practice, and to emphasize the aesthetic and political aspects of software studies. Not reducible to its functional aspects, program code mirrors the instability inherent in the relationship of speech...... expression in the public realm. The book’s line of argument defends language against its invasion by economics, arguing that speech continues to underscore the human condition, however paradoxical this may seem in an era of pervasive computing....

  10. Involvement of ERK1/2 signaling pathway in atrazine action on FSH-stimulated LHR and CYP19A1 expression in rat granulosa cells

    Energy Technology Data Exchange (ETDEWEB)

    Fa, Svetlana; Pogrmic-Majkic, Kristina; Samardzija, Dragana; Glisic, Branka; Kaisarevic, Sonja; Kovacevic, Radmila; Andric, Nebojsa, E-mail: nebojsa.andric@dbe.uns.ac.rs

    2013-07-01

    Worldwide used herbicide atrazine is linked to reproductive dysfunction in females. In this study, we investigated the effects and the mechanism of atrazine action in the ovary using a primary culture of immature granulosa cells. In granulosa cells, follicle-stimulating hormone (FSH) activates both cyclic adenosine monophosphate (cAMP) and extracellular-regulated kinase 1/2 (ERK1/2) cascades, with cAMP pathway being more important for luteinizing hormone receptor (LHR) and aromatase (CYP19A1) mRNA expression. We report that 48 h after atrazine exposure the FSH-stimulated LHR and CYP19A1 mRNA expression and estradiol synthesis were decreased, with LHR mRNA being more sensitive to atrazine than CYP19A1 mRNA. Inadequate acquisition of LHR in the FSH-stimulated and atrazine-exposed granulosa cells renders human chorionic gonadotropin (hCG) ineffective to stimulate amphiregulin (Areg), epiregulin (Ereg), and progesterone receptor (Pgr) mRNA expression, suggesting anti-ovulatory effect of atrazine. To dissect the signaling cascade involved in atrazine action in granulosa cells, we used U0126, a pharmacological inhibitor of ERK1/2. U0126 prevents atrazine-induced decrease in LHR and CYP19A1 mRNA levels and estradiol production in the FSH-stimulated granulosa cells. ERK1/2 inactivation restores the ability of hCG to induce expression of the ovulatory genes in atrazine-exposed granulosa cells. Cell-based ELISA assay revealed that atrazine does not change the FSH-stimulated ERK1/2 phosphorylation in granulosa cells. The results from this study reveal that atrazine does not affect but requires ERK1/2 phosphorylation to cause decrease in the FSH-induced LHR and CYP19A1 mRNA levels and estradiol production in immature granulosa cells, thus compromising ovulation and female fertility. - Highlights: • Atrazine inhibits estradiol production in FSH-stimulated granulosa cells. • Atrazine inhibits LHR and Cyp19a1 mRNA expression in FSH-stimulated granulosa cells. • Atrazine

  11. Utilização de acetochlor e atrazine aplicados em mistura de tanque com dessecantes no sistema de plantio direto Reaction of the herbicides acetochlor and atrazine applied in tank mixtures with desiccants in no-till system

    Directory of Open Access Journals (Sweden)

    Benedito N. Rodrigues

    2000-08-01

    Full Text Available A mistura em tanque de herbicidas dessecantes com residuais tem sido utilizada com frequencia pelos agricultores no sistema de plantio direto. Sabe-se, no entanto, que alguns herbicidas residuais têm problemas de retenção na palha quando utilizados isoladamente em préemergência nesse sistema. O objetivo do presente trabalho, foi estudar o comportamento dos herbicidas residuais atrazine e acetochlor em mistura com dessecantes no manejo em plantio direto. Para tal, foi instalado um experimento em blocos ao acaso com parcelas subdivididas e quatro repetições. Os tratamentos, alocados na parcela, em número de nove, foram constituidos pelas seguintes misturas de herbicidas: 1 acetochlor + glyphosate; 2 acetochlor + glyphosate + 2,4D; 3 acetochlor + paraquat; 4 acetochlor + paraquat + 2,4D; 5 atrazine + glyphosate; 6 atrazine + glyphosate + 2,4D; 7 atrazine + paraquat; 8 atrazine + óleo vegetal; 9 testemunha não tratada. Os tratamentos da sub parcela, em número de dois, foram constituidos pelas modalidades de aplicação dos herbicidas na cobertura vegetal: 1 aplicação com a cobertura "em pé"; 2 aplicação com a cobertura "rolada". A cobertura vegetal de inverno era formada pela consorciação de aveia-preta + ervilhaca comum. Os resultados mostraram que o controle de Brachiaria plantaginea, Euphorbia heterophylla e Bidens pilosa foi melhor efetuado com os tratamentos onde entrou o atrazine. De maneira geral, o controle obtido na modalidade "em pé," foi melhor do que na modalidade "rolada," principalmente nos tratamentos com acetochlor. A análise cromatográfica de resíduos feita em amostras de solo retiradas do experimento antes e após uma chuva de 41mm ocorrida 24 horas após a aplicação dos tratamentos, mostrou que menos de 6 % do acetochlor aplicado foi detectado no solo, em ambas as modalidades de aplicação. Quanto ao atrazine, no entanto, mais de 78 % do total aplicado foi detectado no solo após a chuva na modalidade

  12. The Aster code; Code Aster

    Energy Technology Data Exchange (ETDEWEB)

    Delbecq, J.M

    1999-07-01

    The Aster code is a 2D or 3D finite-element calculation code for structures developed by the R and D direction of Electricite de France (EdF). This dossier presents a complete overview of the characteristics and uses of the Aster code: introduction of version 4; the context of Aster (organisation of the code development, versions, systems and interfaces, development tools, quality assurance, independent validation); static mechanics (linear thermo-elasticity, Euler buckling, cables, Zarka-Casier method); non-linear mechanics (materials behaviour, big deformations, specific loads, unloading and loss of load proportionality indicators, global algorithm, contact and friction); rupture mechanics (G energy restitution level, restitution level in thermo-elasto-plasticity, 3D local energy restitution level, KI and KII stress intensity factors, calculation of limit loads for structures), specific treatments (fatigue, rupture, wear, error estimation); meshes and models (mesh generation, modeling, loads and boundary conditions, links between different modeling processes, resolution of linear systems, display of results etc..); vibration mechanics (modal and harmonic analysis, dynamics with shocks, direct transient dynamics, seismic analysis and aleatory dynamics, non-linear dynamics, dynamical sub-structuring); fluid-structure interactions (internal acoustics, mass, rigidity and damping); linear and non-linear thermal analysis; steels and metal industry (structure transformations); coupled problems (internal chaining, internal thermo-hydro-mechanical coupling, chaining with other codes); products and services. (J.S.)

  13. Development of Visualization Software for McCARD Code

    Science.gov (United States)

    Park, Chang Je; Lee, Byungchul; Shim, Hyung Jin; Yoeng Choi, Kwang; Roh, Chang Hyun

    2014-06-01

    In order to confirm geometrical modeling of input file of the McCARD (Monte Carlo Code for Advanced Reactor Design and analysis) code, a 2D visualization program with a 3D modeling has been developed. It requires lots of mathematical operations and advanced technologies for design graphical program of complicated geometries. The software is coded with the visual C++ language and run under the Windows PC environment.

  14. PC12 differentiation on biopolymer nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Cecchini, Marco [Scuola Normale Superiore and NEST-CNR-INFM, Pisa (Italy); Bumma, Giorgia [Scuola Normale Superiore and Italian Institute of Technology, Pisa (Italy); Serresi, Michela [Scuola Normale Superiore and Italian Institute of Technology, Pisa (Italy); Beltram, Fabio [Scuola Normale Superiore and NEST-CNR-INFM, Pisa (Italy)

    2007-12-19

    The study of nervous system regeneration and axonal outgrowth control are relevant in several research areas, like neurophysiology or biomedical engineering. Among the elements that control neuron dynamics, the host substrate topography is a key parameter in determining cell differentiation. We present time-lapse experiments to analyze the differentiation dynamics of PC12 cells on nanopatterned biocompatible substrates. 200 nm depth gratings were fabricated on tissue-culture polystyrene substrates by nanoimprint lithography; different linewidths and pitches were compared down to 500 nm and 1000 nm, respectively. PC12 cells were cultured on these substrates and, following NGF administration to the medium, body morphology, cell movement and neuritogenesis were monitored at different time periods. In addition to demonstrating guided differentiation, our studies show complex time variations in body morphology and axon length, and guided cell movement. We show unstable synaptic connections and cell-body polarization, and the competition between topographical guidance and cell-cell interactions.

  15. PC12 differentiation on biopolymer nanostructures

    Science.gov (United States)

    Cecchini, Marco; Bumma, Giorgia; Serresi, Michela; Beltram, Fabio

    2007-12-01

    The study of nervous system regeneration and axonal outgrowth control are relevant in several research areas, like neurophysiology or biomedical engineering. Among the elements that control neuron dynamics, the host substrate topography is a key parameter in determining cell differentiation. We present time-lapse experiments to analyze the differentiation dynamics of PC12 cells on nanopatterned biocompatible substrates. 200 nm depth gratings were fabricated on tissue-culture polystyrene substrates by nanoimprint lithography; different linewidths and pitches were compared down to 500 nm and 1000 nm, respectively. PC12 cells were cultured on these substrates and, following NGF administration to the medium, body morphology, cell movement and neuritogenesis were monitored at different time periods. In addition to demonstrating guided differentiation, our studies show complex time variations in body morphology and axon length, and guided cell movement. We show unstable synaptic connections and cell-body polarization, and the competition between topographical guidance and cell-cell interactions.

  16. PC12 polarity on biopolymer nanogratings

    Energy Technology Data Exchange (ETDEWEB)

    Cecchini, M; Ferrari, A; Beltram, F [Scuola Normale Superiore and NEST-CNR-INFM, Pisa (Italy); Scuola Normale Superiore and Italian Institute of Technology, Pisa (Italy)], E-mail: m.cecchini@sns.it

    2008-03-15

    Cell differentiation properties are strongly entangled with the morphology and physical properties of the extracellular environment. A complete understanding of this interaction needs artificial scaffolds with controlled nano-/micro-topography. We induced specific topographies by nanoimprint lithography (NIL) on tissue culture polystyrene (TCPS) dishes substrates and, using light microscopy and high-magnification scanning-electron-microscopy, quantitatively compared the changes in PC12 differentiation phenotype induced by the periodicity of the nanopatterns. This analysis revealed that nanogratings reduce the number of neurites produced by PC12 cells upon treatment with NGF and that neuronal bipolarity correlated with an increased stretching of the cell body and a reduced length of the cell neuronal protrusions.

  17. Optimal codes as Tanner codes with cyclic component codes

    DEFF Research Database (Denmark)

    Høholdt, Tom; Pinero, Fernando; Zeng, Peng

    2014-01-01

    In this article we study a class of graph codes with cyclic code component codes as affine variety codes. Within this class of Tanner codes we find some optimal binary codes. We use a particular subgraph of the point-line incidence plane of A(2,q) as the Tanner graph, and we are able to describe...... the codes succinctly using Gröbner bases....

  18. Implications of a ${J}^{PC}$ exotic

    CERN Document Server

    Page, P R

    1997-01-01

    Recent experimental data from BNL on the isovector J^PC =1^-+ exotic at 1.6 GeV indicate the existence of a non-quarkonium state consistent with lattice gauge theory predictions. We discuss how further experiments can strengthen this conclusion. We show that the \\rho\\pi, \\eta'\\pi and \\eta\\pi couplings of this state qualitatively support the hypothesis that it is a hybrid meson, although other interpretations cannot be eliminated.

  19. Sorção do herbicida atrazine em complexos organominerais

    OpenAIRE

    2001-01-01

    Este trabalho foi desenvolvido com o objetivo de avaliar a sorção do atrazine em complexos organominerais predominantes em solos tropicais. A amostra de herbicida utilizada na experimentação continha 97% de pureza. Alíquotas de 10 mL das soluções de 0,0; 10,0; 20,0; 40,0; 70,0; e 100,0 mmol L-1 de atrazine foram adicionadas aos seguintes substratos: ácidos húmicos, caulinita, goethita, ferridrita, ácidos húmicos+caulinita, ácidos húmicos+ goethita e ácidos húmicos+ferridrita; o extrator utili...

  20. Rapid determination of atrazine in environmental water samples by a novel liquid phase microextraction

    Institute of Scientific and Technical Information of China (English)

    Qing Xiang Zhou; Guo Hong Xie; Long Pang

    2008-01-01

    A novel method was described for the rapid determination of atrazine using dispersive liquid phase microextraction incombination with high performance liquid chromatography (HPLC). Possible impact parameters such as sample pH, extraction anddisperser solvents, salting-out effect, and extraction time were investigated. The experimental results indicated that proposedmethod possessed an excellent analytical performance. The linear range, detection limit, and precision (R.S.D.) were 0.1-50 ng mL-1 (R2 = 0.9955), 0.601 ng mL-1 and 6.4%, respectively. The proposed method was validated with the real water samples,and the spiked recoveries were in the range of 69.9-89.8%, respectively. These results indicated that the established method withhigh enrichment factor, short extraction time was an excellent alternative for the routine analysis of atrazine in environmentalsamples.

  1. THE STUDY OF METHODS FOR DETERMINATION OF METABOLISM BASED RESISTANCE OF ABUTILON THEOPHRASTI MEDIC. TO ATRAZINE

    Directory of Open Access Journals (Sweden)

    DANIJELA PAVLOVIĆ

    2008-05-01

    Full Text Available Different methods for recording morphological and physiological parameters were used to define the level of susceptibility/resistance of Abutilon theophrasti populations to atrazine, in the period between 2002 and 2003. Three different populations of A. theophrasti from the fields near Belgrade were investigated. Total leaf weight and fresh and dry shoot weight among morphological parameters as well as transpiration, water vapour diffusion, chlorophyll fluorescence and total amount of chlorophyll among physiological parameters were measured. Minor differences to atrazine application between the tested populations of A. theophrasti were observed. There are some differences in all morphological parameters, but the most informative ones were the total fresh and dry shoot weight. Although the measurements of chlorophyll fluorescence caused lower differences between tested populations, this method proved itself as most sensitive among physiological methods. Calculated resistance indexes based on different parameters ranged from 2.2 to 15.9.

  2. Effect of linear alkylbenzene sulfonate (LAS) and atrazine on marine microalgae.

    Science.gov (United States)

    Debelius, B; Forja, J M; Del Valls, A; Lubián, L M

    2008-01-01

    Five marine microalgae (Tetraselmis chuii, Rhodomonas salina, Chaetoceros sp., Isochrysis galbana (T-iso) and Nannochloropsis gaditana), in the same biovolume quantity, were exposed to 72h growth-inhibition tests with atrazine and LAS. In all cases, the inhibition effect of atrazine was higher than that of LAS up to two orders of magnitude higher in the case of T. chuii. In a second part of the study, initial cellular densities for each microalga strain and fixed organic compound concentration were varied, and results show density has a clear influence in growth inhibition tests. Finally, the sum of all data obtained in the study was expressed in terms of "toxic cellular quota" (mass of chemical substance per cell). The result was a sigmoid curve with a good fit, including the two main factors in toxicity tests, initial cellular density and contaminant concentration. This toxic cellular quota exhibits a general tendency to increase with cell volume/size.

  3. Ageing of atrazine in manure amended soils assessed by bioavailability to Pseudomonas sp. strain ADP

    DEFF Research Database (Denmark)

    Glæsner, Nadia; Bælum, Jacob; Strobel, Bjarne W.;

    2014-01-01

    bacteria Pseudomonas sp. strain ADP. Throughout an ageing period of 90 days bioavailability was investigated at days 1, 10, 32, 60 and 90, where ~108 cells g−1 of the ADP strain was inoculated to the 14C-atrazine exposed soil and 14CO2 was collected over 7 days as a measure of mineralized atrazine. Even...... though the bioavailable residue decreased in all of the three soils as time proceeded, we found that ageing occurred faster in the topsoils rich in organic carbon than in subsoil. For one topsoil rich in organic carbon content, Simmelkær, we observed a higher degree of ageing when treated with manure....... Contrarily, sorption experiments showed less sorption to Simmelkær treated with manure than the untreated soil indicating that sorption processes are not the only mechanisms of ageing. The other topsoil low in organic carbon content, Ringe, showed no significant difference in ageing between the manure...

  4. PC8 [corrected], a new member of the convertase family.

    Science.gov (United States)

    Bruzzaniti, A; Goodge, K; Jay, P; Taviaux, S A; Lam, M H; Berta, P; Martin, T J; Moseley, J M; Gillespie, M T

    1996-03-15

    A novel subtilisin-like protein, PC8, was identified by PCR using degenerate primers to conserved amino acid residues in the catalytic region of members of the prohormone convertase family. PC8 was predicted to be 785 residues long and was structurally related to the mammalian convertases furin, PACE4, PC1 and PC2, sharing more than 50% amino acid identity over the catalytic region with these family members. PC8 possessed the catalytically important Asp, His, Asn and Ser amino acids, the homo B domain of this family of enzymes and a C-terminal hydrophobic sequence indicative of a transmembrane domain. Structurally, PC8 is more related to furin and PACE4 than to PC1 or PC2. Like furin and PACE4, PC8 mRNA was found to be widely expressed; this is in contrast with PC1 and PC2, which have a restricted distribution. Two transcripts, of 4.5 and 3.5 kb, were detected in both human cell lines and rat tissues. Unlike furin and PACE4, both of which map to chromosome 15, PC8 maps to chromosome 11q23-11q24, suggesting that this gene may have resulted from an ancient gene duplication event from either furin or PACE4, or conversely that these genes arose from PC8.

  5. Adsorption of atrazine on hemp stem-based activated carbons with different surface chemistry

    OpenAIRE

    Lupul, Iwona; Yperman, Jan; Carleer, Robert; Gryglewicz, Grazyna

    2015-01-01

    Surface-modified hemp stem-based activated carbons (HACs) were prepared and used for the adsorption of atrazine from aqueous solution, and their adsorption performance was examined. A series of HACs were prepared by potassium hydroxide activation of hemp stems, followed by subsequent modification by thermal annealing, oxidation with nitric acid and amination. The resultant HACs differed in surface chemistry, while possessing similar porous structure. The surface group characteristics were exa...

  6. Chlorpyrifos and atrazine removal from runoff by vegetated filter strips: experiments and predictive modeling.

    Science.gov (United States)

    Poletika, N N; Coody, P N; Fox, G A; Sabbagh, G J; Dolder, S C; White, J

    2009-01-01

    Runoff volume and flow concentration are hydrological factors that limit effectiveness of vegetated filter strips (VFS) in removing pesticides from surface runoff. Empirical equations that predict VFS pesticide effectiveness based solely on physical characteristics are insufficient on the event scale because they do not completely account for hydrological processes. This research investigated the effect of drainage area ratio (i.e., the ratio of field area to VFS area) and flow concentration (i.e., uniform versus concentrated flow) on pesticide removal efficiency of a VFS and used these data to provide further field verification of a recently proposed numerical/empirical modeling procedure for predicting removal efficiency under variable flow conditions. Runoff volumes were used to simulate drainage area ratios of 15:1 and 30:1. Flow concentration was investigated based on size of the VFS by applying artificial runoff to 10% of the plot width (i.e., concentrated flow) or the full plot width (i.e., uniform flow). Artificial runoff was metered into 4.6-m long VFS plots for 90 min after a simulated rainfall of 63 mm applied over 2 h. The artificial runoff contained sediment and was dosed with chlorpyrifos and atrazine. Pesticide removal efficiency of VFS for uniform flow conditions (59% infiltration; 88% sediment removal) was 85% for chlorpyrifos and 62% for atrazine. Flow concentration reduced removal efficiencies regardless of drainage area ratio (i.e., 16% infiltration, 31% sediment removal, 21% chlorpyrifos removal, and 12% atrazine removal). Without calibration, the predictive modeling based on the integrated VFSMOD and empirical hydrologic-based pesticide trapping efficiency equation predicted atrazine and chlorpyrifos removal efficiency under uniform and concentrated flow conditions. Consideration for hydrological processes, as opposed to statistical relationships based on buffer physical characteristics, is required to adequately predict VFS pesticide trapping

  7. Mixed-mode sorption of hydroxylated atrazine degradation products to sell: A mechanism for bound residue

    Science.gov (United States)

    Lerch, R.N.; Thurman, E.M.; Kruger, E.L.

    1997-01-01

    This study tested the hypothesis that sorption of hydroxylated atrazine degradation products (HADPs: hydroxyatrazine, HA; deethylhydroxyatrazine, DEHA; and deisopropylhydroxyatrazine, DIHA) to soils occurs by mixed-mode binding resulting from two simultaneous mechanisms: (1) cation exchange and (2) hydrophobic interaction. The objective was to use liquid chromatography and soil extraction experiments to show that mixed-mode binding is the mechanism controlling HADP sorption to soils and is also a mechanism for bound residue. Overall, HADP binding to solid-phase extraction (SPE) sorbents occurred in the order: cation exchange >> octadecyl (C18) >> cyanopropyl. Binding to cation exchange SPE and to a high-performance liquid chromatograph octyl (C8) column showed evidence for mixed-mode binding. Comparison of soil extracted by 0.5 M KH2P04, pH 7.5, or 25% aqueous CH3CN showed that, for HA and DIHA, cation exchange was a more important binding mechanism to soils than hydrophobic interaction. Based on differences between several extractants, the extent of HADP mixed-mode binding to soil occurred in the following order: HA > DIHA > DEHA. Mixed-mode extraction recovered 42.8% of bound atrazine residues from aged soil, and 88% of this fraction was identified as HADPs. Thus, a significant portion of bound atrazine residues in soils is sorbed by the mixed-mode binding mechanisms.

  8. Sonolytic, photolytic, and photocatalytic decomposition of atrazine in the presence of polyoxometalates.

    Science.gov (United States)

    Hiskia, A; Ecke, M; Troupis, A; Kokorakis, A; Hennig, H; Papaconstantinou, E

    2001-06-01

    Aqueous solutions of atrazine [2-chloro-4-(isopropylamino)-6-(ethylamino)-s-triazine] (CIET) decompose upon illumination with a low-pressure Hg-arc lamp (254 nm). However, no decomposition takes place with lambda > 300 nm. On the other hand, addition of polyoxometalates (POM), PW12O40(3-) or SiW12O40(4-), into a solution of atrazine photodecomposes the substrate within a few minutes (cutoff fiter 320 nm). Ultrasound (US) treatment also decomposes aqueous solutions of atrazine within a few minutes. Both methods, sonolysis and photolysis with POM, give common intermediates, namely, 2-hydroxy-4-(isopropylamino)-6-amino-s-triazine (OIET), 2-chloro-4-(isopropylamino)-6-amino-s-triazine (CIAT), 2-chloro-4-amino-6-(ethylamino)-s-triazine (CAET), 2-hydroxy-4,6-diamino-s-triazine (OAAT), and 2-hydroxy-4-hydroxy-6-amino-s-triazine (OOAT) among others. The final products for both methods, US and photolysis with POM, were cyanuric acid (OOOT), NO3-, Cl-, CO2, and H2O. OOOT showed no signs of decomposition by sonication and/or photolysis with POM. It also resisted degradation upon photolysis with plain UV light (254 nm). However, it has been reported to decompose upon photolysis with lambda > 200 nm. Combination of US and photolysis with POM produces only a cumulative effect.

  9. Development of a bacterial bioassay for atrazine and cyanuric acid detection

    Directory of Open Access Journals (Sweden)

    Anna eHUA

    2015-03-01

    Full Text Available The s-triazine herbicides are compounds which can disseminate into soils and water. Due to their toxic effects on living organisms, their concentrations in drinking water are legislated by WHO recommendations. Here we have developed for the first time, to the best of our knowledge, an alternative method for physicochemical quantification using two bioluminescent bacterial biosensors: E. coli SM003 for cyanuric acid detection and E. coli SM004 for both atrazine and cyanuric acid detection. The concentration of cyanuric acid detection for E. coli SM003 ranges from 7.83 µM to 2.89 mM, and for E. coli SM004 ranges from 0.22 µM to 15 µM. Moreover, atrazine detection by E. coli SM004 ranges from 1.08 µM to 15 µM. According to WHO recommendations, the cyanuric acid detection range is sensitive enough to discriminate between polluted and drinking water. Nevertheless, the detection of atrazine by E. coli SM004 is only applicable for high concentrations of contaminants.

  10. Some biological and hematological responses of Oreochromis niloticus juveniles exposed to Atrazine herbicide

    Directory of Open Access Journals (Sweden)

    Fidelis Bekeh Ada

    2012-12-01

    Full Text Available This research was aimed at finding the influence of Atrazine on a most widely farmed fish,Oreochromis niloticus (Linnaeus, 1758, in Nigeria. Specific areas of investigation were to find the LC50after 24, 48, 72 and 96 hours of the chemical administration to the fish. The effects of the chemical onthe behavioral and biological responses of O. niloticus were equally observed. The ten fish each werestocked in six different tanks containing 40 liters of water. These tanks contained graded concentrationsof the chemical and the treatments were replicated three times. Dissolved oxygen content was reducingwith increasing Atrazine concentration, while temperature and pH increased with increasing Atrazineconcentration. The LC50 of Atrazine in 24, 48, 72 and 96 hours were 7.9, 7.6, 7.3 and 7.2 respectively.Behavioral and biological responses included loss of reflex, air gulping, erratic swimming, discoloration,hemorrhage and molting. The blood parameters observed showed that there were increases in packedcell volume (PCV and red blood cell count (RBC and decrease in hemoglobin (Hb, erythrocytesedimentation rate (ESR and mean cell hemoglobin (MCH, while there was no significant change inwhite blood cell count (WBC and mean cell volume (MCV values. The chemical was therefore observedto be lethal to juvenile O. niloticus.

  11. Competitive biodegradation of dichlobenil and atrazine coexisting in soil amended with a char and citrate

    Energy Technology Data Exchange (ETDEWEB)

    Qiu Yuping; Pang Hui; Zhou Zunlong [College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032 (China); Zhang Ping [Department of Civil Engineering, University of Minnesota, Minneapolis, MN 55455 (United States); Feng Yucheng [Department of Agronomy and Soils, Auburn University, Auburn, AL 36849 (United States); Sheng, G. Daniel, E-mail: dansheng@zjut.edu.c [College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032 (China)

    2009-11-15

    The role of char nutrients in the biodegradation of coexisting dichlobenil and atrazine in a soil by their respective bacterial degraders, DDN and ADP, was evaluated. Under growing conditions, their degradation in soil extract was slow with <40% and <20% degraded within 64 h, respectively. The degradation in extracts and slurries of char-amended solids increased with increasing char content, due to nutritional stimulation on microbial activities. By supplementing soil extract with various major nutrients, the measured degradation demonstrated that P was the exclusive limiting nutrient. The reduction in the degradation of coexisting dichlobenil and atrazine resulted apparently from the competitive utilization of P by DDN and ADP. With a shorter lag phase, ADP commenced growing earlier than DDN with the advantage of utilizing P first in insufficient supply. This resulted in an inhibition on the growth of DDN and thus suppression on dichlobenil degradation. - Competitive utilization of char nutrients by bacterial degraders resulted in the preferential biodegradation of atrazine over dichlobenil in a soil containing a wheat-straw-derived char.

  12. Conductometric tyrosinase biosensor for the detection of diuron, atrazine and its main metabolites.

    Science.gov (United States)

    Anh, Tuan Mai; Dzyadevych, Sergei V; Van, Minh Chau; Renault, Nicole Jaffrezic; Duc, Chien Nguyen; Chovelon, Jean-Marc

    2004-05-28

    The determination of diuron, atrazine, desisopropylatrazine (DIA) and desethylatrazine (DEA) were investigated using conductometric tyrosinase biosensor. Tyrosinase was immobilised on the biosensor sensitive part by allowing it to mix with bovine serum albumin (BSA) and then cross-linking in saturated glutaraldehyde (GA) vapour for 30min. The determination of pollutants in a solution was performed by comparison of the output signal (i.e percentage of the enzymatic activity) of the biosensor before and after contact with pollutants. The measurement of the enzymatic activity was performed using 4-chlorophenol, phenol and catechol substrates and response times ranging from 1 to 5min were observed. A 4-chlorophenol substrate was used to detect pesticides. A 30min contact time of the biosensor in the pollutant solution was used. Under the experimental conditions employed, detection limits for diuron and atrazine were about 1ppb and dynamic range of 2.3-2330 and 2.15-2150ppb were obtained for diuron and atrazine, respectively. A relative standard deviation (n=3) of the output signal was estimated to be 5% and a slight drift of 1.5muSh(-1) was observed. The 90% of the enzyme activity was still maintained after 23 days of storage in a buffer solution at 4 degrees C.

  13. The potential applications of using compost chars for removing the hydrophobic herbicide atrazine from solution

    Science.gov (United States)

    Tsui, L.; Roy, W.R.

    2008-01-01

    One commercial compost sample was pyrolyzed to produce chars as a sorbent for removing the herbicide atrazine from solution. The sorption behavior of compost-based char was compared with that of an activated carbon derived from corn stillage. When compost was pyrolyzed, the char yield was greater than 45% when heated under air, and 52% when heated under N2. In contrast, when the corn stillage was pyrolyzed under N2, the yield was only 22%. The N2-BET surface area of corn stillage activated carbon was 439 m2/g, which was much greater than the maximum compost char surface area of 72 m2/g. However, the sorption affinity of the compost char for dissolved atrazine was comparable to that of the corn stillage activated carbon. This similarity could have resulted from the initial organic waste being subjected to a relatively long period of thermal processes during composting, and thus, the compost was more thermally stable when compared with the raw materials. In addition, microorganisms transformed the organic wastes into amorphous humic substances, and thus, it was likely that the microporisity was enhanced. Although this micropore structure could not be detected by the N2-BET method, it was apparent in the atrazine sorption experiment. Overall, the experimental results suggested that the compost sample in current study was a relatively stable material thermally for producing char, and that it has the potential as a feed stock for making high-quality activated carbon. ?? 2007 Elsevier Ltd. All rights reserved.

  14. Fe@Fe2O3 promoted electrochemical mineralization of atrazine via a triazinon ring opening mechanism.

    Science.gov (United States)

    Ding, Xing; Wang, Shengyao; Shen, Wanqiu; Mu, Yi; Wang, Li; Chen, Hao; Zhang, Lizhi

    2017-04-01

    In this study, an electrochemical/electro-Fenton oxidation (EC/EF) system was designed to degrade atrazine, by utilizing boron-doped diamond (BDD) and Fe@Fe2O3 core-shell nanowires loaded active carbon fiber (Fe@Fe2O3/ACF) as the anode and the cathode, respectively. This EC/EF system exhibited much higher degradation rate, decholorination and mineralization efficiency of atrazine than the electrochemical (EC) and electrochemical/traditional electro-Fenton (EC/TEF) oxidation counterpart systems without Fe@Fe2O3 core-shell nanowires. Active species trapping experiment revealed that Fe@Fe2O3 could activate molecular oxygen to produce more OH through Fenton reaction, which favored the atrazine degradation. High performance liquid chromatography, high performance liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry were applied to probe the decomposition and mineralization of atrazine during this novel EC/EF process, which revealed that two intermediates of triazinons (the isomerization of hydroxylated atrazine) were generated during the electrochemical/electro-Fenton oxidation of atrazine in the presence of Fe@Fe2O3 core-shell nanowires. The experimental and theoretical calculation results suggested that atrazine might be degraded via a triazinon ring opening mechanism, while the presence of Fe@Fe2O3 notably accelerated the decholorination process, and produced more hydroxylated products to promote the generation of trazinons and the subsequent ring cleavage as well as the final complete mineralization. This work provides a deep insight into the triazine ring opening mechanism and the design of efficient electrochemical advanced oxidation technologies (EAOTs) for persistent organic pollutant removal.

  15. Oxidative decomposition of atrazine in water in the presence of hydrogen peroxide using an innovative microwave photochemical reactor

    Energy Technology Data Exchange (ETDEWEB)

    Chen Huilun [Department of Environmental Engineering, Civil and Environment Engineering School, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083 (China); Italian National Research Council-Istituto di Chimica dei Composti Organometallici (ICCOM), Via G. Moruzzi 1, 56124 Pisa (Italy); Bramanti, Emilia, E-mail: ebramanti@iccom.cnr.it [Italian National Research Council-Istituto di Chimica dei Composti Organometallici (ICCOM), Via G. Moruzzi 1, 56124 Pisa (Italy); Longo, Iginio [Italian National Research Council-National Institute of Optics (INO), Via G. Moruzzi 1, 56124 Pisa (Italy); Onor, Massimo [Italian National Research Council-Istituto di Chimica dei Composti Organometallici (ICCOM), Via G. Moruzzi 1, 56124 Pisa (Italy); Ferrari, Carlo [Italian National Research Council-National Institute of Optics (INO), Via G. Moruzzi 1, 56124 Pisa (Italy)

    2011-02-28

    The simultaneous application of microwave (MW) power and UV light leads to improved results in photochemical processes. This study investigates the oxidative decomposition of atrazine in water using an innovative MW and UV photochemical reactor, which activates a chemical reaction with MW and UV radiation using an immersed source without the need for a MW oven. We investigated the influence of reaction parameters such as initial H{sub 2}O{sub 2} concentrations, reaction temperatures and applied MW power and identified the optimal conditions for the oxidative decomposition of atrazine. Atrazine was completely degraded by MW/UV/H{sub 2}O{sub 2} in a very short time (i.e. t{sub 1/2} = 1.1 min for 20.8 mg/L in optimal conditions). From the kinetic study, the disappearance rate of atrazine can be expressed as dX/dt = k{sub PH}[M]{sub 0}(b - X)(1 - X), where b {identical_to} [H{sub 2}O{sub 2}]{sub 0}/[M]{sub 0} + k{sub OH}[{center_dot}OH]/k{sub PH}[M]{sub 0}, and X is the atrazine conversion, which correlates well with the experimental data. The kinetic analysis also showed that an indirect reaction of atrazine with an OH radical is dominant at low concentrations of H{sub 2}O{sub 2} and a direct reaction of atrazine with H{sub 2}O{sub 2} is dominant when the concentration of H{sub 2}O{sub 2} is more than 200 mg/L.

  16. Watershed Regressions for Pesticides (WARP) for Predicting Annual Maximum and Annual Maximum Moving-Average Concentrations of Atrazine in Streams

    Science.gov (United States)

    Stone, Wesley W.; Gilliom, Robert J.; Crawford, Charles G.

    2008-01-01

    Regression models were developed for predicting annual maximum and selected annual maximum moving-average concentrations of atrazine in streams using the Watershed Regressions for Pesticides (WARP) methodology developed by the National Water-Quality Assessment Program (NAWQA) of the U.S. Geological Survey (USGS). The current effort builds on the original WARP models, which were based on the annual mean and selected percentiles of the annual frequency distribution of atrazine concentrations. Estimates of annual maximum and annual maximum moving-average concentrations for selected durations are needed to characterize the levels of atrazine and other pesticides for comparison to specific water-quality benchmarks for evaluation of potential concerns regarding human health or aquatic life. Separate regression models were derived for the annual maximum and annual maximum 21-day, 60-day, and 90-day moving-average concentrations. Development of the regression models used the same explanatory variables, transformations, model development data, model validation data, and regression methods as those used in the original development of WARP. The models accounted for 72 to 75 percent of the variability in the concentration statistics among the 112 sampling sites used for model development. Predicted concentration statistics from the four models were within a factor of 10 of the observed concentration statistics for most of the model development and validation sites. Overall, performance of the models for the development and validation sites supports the application of the WARP models for predicting annual maximum and selected annual maximum moving-average atrazine concentration in streams and provides a framework to interpret the predictions in terms of uncertainty. For streams with inadequate direct measurements of atrazine concentrations, the WARP model predictions for the annual maximum and the annual maximum moving-average atrazine concentrations can be used to characterize

  17. Role of e{sub aq}{sup −}, ·OH and H· in radiolytic degradation of atrazine: A kinetic and mechanistic approach

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Javed Ali, E-mail: javed_chemistry@yahoo.com [Radiation Chemistry Laboratory, National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar 25120 (Pakistan); Shah, Noor S. [Radiation Chemistry Laboratory, National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar 25120 (Pakistan); Institute of Chemical Sciences, University of Swat, Swat 19130 (Pakistan); Nawaz, Shah; Ismail, M.; Rehman, Faiza [Radiation Chemistry Laboratory, National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar 25120 (Pakistan); Khan, Hasan M., E-mail: hmkhan@upesh.edu.pk [Radiation Chemistry Laboratory, National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar 25120 (Pakistan)

    2015-05-15

    Highlights: • Atrazine was efficiently removed from aqueous solution by γ-ray irradiation. • e{sub aq}{sup −} was found to have more crucial role in removal of atrazine than ·OH. • Atrazine degradation was reduced in the presence of t-BuOH and i-PrOH. • Atrazine showed high stability at neutral pH than at very low and high pH conditions. • Potential degradation mechanism was evaluated by GC–MS analysis. - Abstract: The degradation of atrazine was investigated in aqueous solution by gamma-ray irradiation. 8.11 μM initial atrazine concentration could be completely removed in N{sub 2} saturated solution by applying 3500 Gy radiation dose at a dose rate of 296 Gy h{sup −1}. Significant removal of atrazine (i.e., 39.4%) was observed at an absorbed dose of 1184 Gy in air saturated solution and the removal efficiency was promoted to 50.5 and 65.4% in the presence of N{sub 2}O and N{sub 2} gases, respectively. The relative contributions of hydrated electron, hydroxyl radical and hydrogen radical toward atrazine degradation were determined as ratio of observed dose constant (k{sub obs}) and found to be 5: 3: 1 for k{sub eaq}{sup −}: k{sub ·OH}: k{sub H}·, respectively. The degradation efficiency of atrazine was 69.5, 55.6 and 37.3% at pH 12.1, 1.7 and 5.7, respectively. A degradation mechanism was proposed based on the identified degradation by-products by gas chromatography–mass spectrometry. Taking the relative contributions of oxidative and reductive species to atrazine degradation into account, reductive pathway proved to be a better approach for the radiolytic treatment of atrazine contaminated water.

  18. 39 CFR 501.16 - PC postage payment methodology.

    Science.gov (United States)

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false PC postage payment methodology. 501.16 Section 501.16 Postal Service UNITED STATES POSTAL SERVICE POSTAGE PROGRAMS AUTHORIZATION TO MANUFACTURE AND DISTRIBUTE POSTAGE EVIDENCING SYSTEMS § 501.16 PC postage payment methodology. (a) The PC Postage customer...

  19. Effects of in ovo exposure of Imazalil and Atrazine on sexual differentiation in chick gonads

    Energy Technology Data Exchange (ETDEWEB)

    Yamashita, J.; Ikeda, M. [Univ. of Shizuoka, Shizuoka (Japan); Matsushita, S.; Iwasawa, T.; Ikeya, M. [Shizuoka Swine and Poultry Experiment Station, Kikugawa (Japan)

    2004-09-15

    numerous anti-fungal chemicals. These chemicals have shown to reversibly (although not necessarily competitively) inhibit aromatase activity in human placental microsomes. It is reported that imazalil and difenoconazole inhibit aromatase activity in human adrenocortical carcinoma cell line H295R. Atrazine is the most commonly used herbicide in the word. There are several reports about the adverse effects of atrazine exposure. Atrazine induced hermaphroditism in African clawed frogs and demasculinized the larynx in male frogs. Plasma testosterone concentration in male frogs was decreased by atrazine exposure, and plasma estradiol concentration in rats was increased by atrazine exposure. Atrazine also increased aromatase activity in human adrenocortical carcinoma cell line H295R by inducing aromatase mRNA. In this study, the effects of in ovo exposure to an aromatase-inhibiting chemical (imazalil) and an aromatase-activating chemical (atrazine) on the sexual differentiation of chick gonad were investigated.

  20. Cybernet空间节省型PC

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    你是否有计算过你租用的Office费用占整个办公成本的几成?是否有发现辛苦赚来的钱除去房租物业所剩无几?不能怪你,只能怪目前高档办公志气的租金太高。有什么办法吗?试试Cybernet出品的空间节省型PC-ZPC-900,它将电脑主机整合到一个标准的104键键盘里,

  1. PC-based car license plate reader

    Science.gov (United States)

    Hwang, Chung-Mu; Shu, Shyh-Yeong; Chen, Wen-Yu; Chen, Yie-Wern; Wen, Kuang-Pu

    1992-11-01

    A car license plate reader (CLPR) using fuzzy inference and neural network algorithm has been developed in Industrial Technology Research Institute (ITRI) and installed in highway toll stations to identify stolen cars. It takes an average of 0.7 seconds to recognize a car license plate by using a PC with 80486-50 CPU. The recognition rate of the system is about 97%. The techniques of CLPR include vehicle sensing, image grab control, optic pre- processing, lighting, and optic character recognition (OCR). The CLPR can be used in vehicle flow statistics, the checking of stolen vehicles, automatic charging systems in parking lots or garage management, and so on.

  2. Measuring Bullet Velocity with a PC Soundcard

    CERN Document Server

    Courtney, M; Courtney, Michael; Edwards, Brian

    2006-01-01

    This article describes a simple method for using a PC soundcard to accurately measure bullet velocity. The method involves placing the microphone within a foot of the muzzle and firing at a steel target between 50 and 100 yards away. The time of flight for the bullet is simply the recorded time between muzzle blast and sound of the bullet hitting the target minus the time it takes the sound to return from the target to the microphone. The average bullet velocity is simply the distance from the muzzle to the target divided by the time of flight of the bullet. This method can also be applied to measurement of paintball velocities.

  3. Simulation of branched serial first-order decay of atrazine and metabolites in adapted and nonadapted soils

    Science.gov (United States)

    Webb, Richard M.; Sandstrom, Mark W.; Jason L. Krutz,; Dale L. Shaner,

    2011-01-01

    In the present study a branched serial first-order decay (BSFOD) model is presented and used to derive transformation rates describing the decay of a common herbicide, atrazine, and its metabolites observed in unsaturated soils adapted to previous atrazine applications and in soils with no history of atrazine applications. Calibration of BSFOD models for soils throughout the country can reduce the uncertainty, relative to that of traditional models, in predicting the fate and transport of pesticides and their metabolites and thus support improved agricultural management schemes for reducing threats to the environment. Results from application of the BSFOD model to better understand the degradation of atrazine supports two previously reported conclusions: atrazine (6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine) and its primary metabolites are less persistent in adapted soils than in nonadapted soils; and hydroxyatrazine was the dominant primary metabolite in most of the soils tested. In addition, a method to simulate BSFOD in a one-dimensional solute-transport unsaturated zone model is also presented.

  4. Installation and implementation of PC COSYMA; PC COSYMAn kaeyttoeoenotto ja soveltaminen

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, J. [VTT Energy, Espoo (Finland). Nuclear Energy

    1995-12-01

    COSYMA is a probabilistic reactor accident consequence assessment model developed in the 1980`s by the research institutes of the EC countries, primarily by NRPB and KfK. In 1993 a simplified version of the program was released to be implemented on a PC. In the study the PC COSYMA program was applied to calculate as the end points nuclide concentrations, doses received, numbers of health effects, areas affected by countermeasures and other results related to countermeasure strategies. Some results are compared with the results obtained by the ARANO program developed by VTT Energy (Technical Research Centre of Finland) to quarantee proper interpretation of the application. (15 refs.).

  5. Similarities and differences in occurrence and temporal fluctuations in glyphosate and atrazine in small Midwestern streams (USA) during the 2013 growing season

    Science.gov (United States)

    Mahler, Barbara J.; VanMetre, Peter; Burley, Thomas E.; Loftin, Keith A.; Meyer, Michael T.; Nowell, Lisa H.

    2017-01-01

    Glyphosate and atrazine are the most intensively used herbicides in the United States. Although there is abundant spatial and temporal information on atrazine occurrence at regional scales, there are far fewer data for glyphosate, and studies that compare the two herbicides are rare. We investigated temporal patterns in glyphosate and atrazine concentrations measured weekly during the 2013 growing season in 100 small streams in the Midwestern United States. Glyphosate was detected in 44% of samples (method reporting level 0.2 μg/L); atrazine was detected above a threshold of 0.2 μg/L in 54% of samples. Glyphosate was detected more frequently in 12 urban streams than in 88 agricultural streams, and at concentrations similar to those in streams with high agricultural land use (> 40% row crop) in the watershed. In contrast, atrazine was detected more frequently and at higher concentrations in agricultural streams than in urban streams. The maximum concentration of glyphosate measured at most urban sites exceeded the maximum atrazine concentration, whereas at agricultural sites the reverse was true. Measurement at a 2-day interval at 8 sites in northern Missouri revealed that transport of both herbicide compounds appeared to be controlled by spring flush, that peak concentration duration was brief, but that peaks in atrazine concentrations were of longer duration than those of glyphosate. The 2-day sampling also indicated that weekly sampling is unlikely to capture peak concentrations of glyphosate and atrazine.

  6. Similarities and differences in occurrence and temporal fluctuations in glyphosate and atrazine in small Midwestern streams (USA) during the 2013 growing season.

    Science.gov (United States)

    Mahler, Barbara J; Van Metre, Peter C; Burley, Thomas E; Loftin, Keith A; Meyer, Michael T; Nowell, Lisa H

    2017-02-01

    Glyphosate and atrazine are the most intensively used herbicides in the United States. Although there is abundant spatial and temporal information on atrazine occurrence at regional scales, there are far fewer data for glyphosate, and studies that compare the two herbicides are rare. We investigated temporal patterns in glyphosate and atrazine concentrations measured weekly during the 2013 growing season in 100 small streams in the Midwestern United States. Glyphosate was detected in 44% of samples (method reporting level 0.2μg/L); atrazine was detected above a threshold of 0.2μg/L in 54% of samples. Glyphosate was detected more frequently in 12 urban streams than in 88 agricultural streams, and at concentrations similar to those in streams with high agricultural land use (>40% row crop) in the watershed. In contrast, atrazine was detected more frequently and at higher concentrations in agricultural streams than in urban streams. The maximum concentration of glyphosate measured at most urban sites exceeded the maximum atrazine concentration, whereas at agricultural sites the reverse was true. Measurement at a 2-day interval at 8 sites in northern Missouri revealed that transport of both herbicide compounds appeared to be controlled by spring flush, that peak concentration duration was brief, but that peaks in atrazine concentrations were of longer duration than those of glyphosate. The 2-day sampling also indicated that weekly sampling is unlikely to capture peak concentrations of glyphosate and atrazine.

  7. DEVELOPMENT AND APPLICATION OF IMMUNOAFFINITY COLUMN CHROMATOGRAPHY AS A CLEANUP METHOD FOR THE DETERMINATION OF ATRAZINE IN COMPLEX ENVIRONMENTAL SAMPLE MEDIA

    Science.gov (United States)

    A rabbit antibody immunoaffinity (IA) column procedure was evaluated as a cleanup method for the determination of atrazine in soil, sediment, and food. Four IA columns were prepared by immobilizing a polyclonal rabbit anti-atrazine antibody solution to HiTrap Sepharose columns. A...

  8. NOVEL BIPHASE CODE -INTEGRATED SIDELOBE SUPPRESSION CODE

    Institute of Scientific and Technical Information of China (English)

    Wang Feixue; Ou Gang; Zhuang Zhaowen

    2004-01-01

    A kind of novel binary phase code named sidelobe suppression code is proposed in this paper. It is defined to be the code whose corresponding optimal sidelobe suppression filter outputs the minimum sidelobes. It is shown that there do exist sidelobe suppression codes better than the conventional optimal codes-Barker codes. For example, the sidelobe suppression code of length 11 with filter of length 39 has better sidelobe level up to 17dB than that of Barker code with the same code length and filter length.

  9. IBM PC/IX operating system evaluation plan

    Science.gov (United States)

    Dominick, Wayne D. (Editor); Granier, Martin; Hall, Philip P.; Triantafyllopoulos, Spiros

    1984-01-01

    An evaluation plan for the IBM PC/IX Operating System designed for IBM PC/XT computers is discussed. The evaluation plan covers the areas of performance measurement and evaluation, software facilities available, man-machine interface considerations, networking, and the suitability of PC/IX as a development environment within the University of Southwestern Louisiana NASA PC Research and Development project. In order to compare and evaluate the PC/IX system, comparisons with other available UNIX-based systems are also included.

  10. From concatenated codes to graph codes

    DEFF Research Database (Denmark)

    Justesen, Jørn; Høholdt, Tom

    2004-01-01

    We consider codes based on simple bipartite expander graphs. These codes may be seen as the first step leading from product type concatenated codes to more complex graph codes. We emphasize constructions of specific codes of realistic lengths, and study the details of decoding by message passing...

  11. Pairing and sinking of binary SMBHs in sub-pc resolution simulations of galaxy mergers

    CERN Document Server

    Chapon, Damien; Teyssier, Romain

    2011-01-01

    We study the formation of a supermassive black hole (SMBH) binary and the shrinking of the separation of the two holes to sub-pc scales starting from a realistic major merger between two gas-rich spiral galaxies with mass comparable to our Milky Way. The simulations are the first of this kind carried out with an Adaptive Mesh refinement (AMR) code (here RAMSES), and the first capable to resolve separations as small as 0.1 pc. The collision of the two galaxies produces a gravo-turbulent rotating nuclear disk with mass (\\sim 10^9 Msun) and size (\\sim 60 pc) in excellent agreement with previous SPH simulations with particle splitting that used a similar setup (Mayer et al. 2007) but were limited to separations of a few parsecs. The AMR results confirm that the two black holes sink rapidly as a result of dynamical friction onto the gaseous background, reaching a separation of 1 pc in less than 10^7 yr. We show that the dynamical friction wake is well resolved by our model and we find good agreement with analytica...

  12. 华硕Eee PC 1000H

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    屏幕扩大、外观翻新:低价已经再不是Eee PC的唯一定位,随着全面升级Atom平台和屏幕尺寸扩大,Eee PC开始呈现出消费化的趋势。Eee PC 1000H屏幕尺寸再次扩大,从最初的7英寸、8.9英寸,直到如今的10.2英寸,而屏幕分辨率保持和8.9英寸屏幕相同的1024×600,因此整个字体显示更大,阅读更舒适。1000H采用了和Eee PC901相同的硬件配置:Atom N270、1GB内存和80GB硬盘,

  13. Comparison of Polar Cap (PC) index calculations.

    Science.gov (United States)

    Stauning, P.

    2012-04-01

    The Polar Cap (PC) index introduced by Troshichev and Andrezen (1985) is derived from polar magnetic variations and is mainly a measure of the intensity of the transpolar ionospheric currents. These currents relate to the polar cap antisunward ionospheric plasma convection driven by the dawn-dusk electric field, which in turn is generated by the interaction of the solar wind with the Earth's magnetosphere. Coefficients to calculate PCN and PCS index values from polar magnetic variations recorded at Thule and Vostok, respectively, have been derived by several different procedures in the past. The first published set of coefficients for Thule was derived by Vennerstrøm, 1991 and is still in use for calculations of PCN index values by DTU Space. Errors in the program used to calculate index values were corrected in 1999 and again in 2001. In 2005 DMI adopted a unified procedure proposed by Troshichev for calculations of the PCN index. Thus there exists 4 different series of PCN index values. Similarly, at AARI three different sets of coefficients have been used to calculate PCS indices in the past. The presentation discusses the principal differences between the various PC index procedures and provides comparisons between index values derived from the same magnetic data sets using the different procedures. Examples from published papers are examined to illustrate the differences.

  14. Microbial adaption to a pesticide in agricultural soils: Accelerated degradation of 14C-atrazine in field soils from Brazil and Belgium

    Science.gov (United States)

    Jablonowski, Nicolai David; Martinazzo, Rosane; Hamacher, Georg; Accinelli, Cesare; Köppchen, Stephan; Langen, Ulrike; Linden, Andreas; Krause, Martina; Burauel, Peter

    2010-05-01

    An increasing demand for food, feed and bioenergy, and simultaneously a decline of arable land will require an intensive agricultural production including the use of pesticides. With an increasing use of pesticides the occurrence of an accelerated degradation potential has to be assessed. Atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] is one of the most widely used herbicides in the world. Even though its use was banned in several countries it is still widely used throughout America and the Asia-Pacific region. Atrazine is the most widely used herbicide in maize plantations in Brazil and the US. The use of atrazine in Belgium and all EU member states was banned in September 2004, with the permission to consume existing stocks until October 2005. Atrazine and its residues are still regularly detected in soil, ground and surface waters even years after its prohibition. Its persistence in soil and in association with organic particles might become crucial in terms of erosion due to climate and environmental changes. Due to its potential microbiological accessibility, the microbial mineralization of atrazine competes with chemical/physical interaction such as sorption and binding processes of the chemical molecule in the soil matrix. Binding or intrusion of the chemical on soil components results in a decrease of its accessibility for soil microbes, which does not necessarily exclude the molecule from environmental interactions. In the present study the accelerated atrazine degradation in agriculturally used soils was examined. Soil samples were collected from a Rhodic Ferralsol, Campinas do Sul, South Brazil, and Geric Ferralsol, Correntina, Northeastern Brazil. The sampling site of the Rhodic Ferralsol soil has been under crop rotation (soybean/wheat/maize/oat) since 1990. The Geric Ferralsol site has alternately been cultivated with maize and soybean since 2000. Both areas have been treated biennially with atrazine at recommended doses of 1.5 - 3

  15. User`s guide and documentation manual for ``BOAST-VHS for the PC``

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Ming-Ming; Sarathi, P.; Heemstra, R.J.; Cheng, A.M.; Pautz, J.F.

    1992-01-01

    The recent advancement of computer technology makes reservoir simulations feasible in a personal computer (PC) environment. This manual provides a guide for running BOAST-VHS, a black oil reservoir simulator for vertical/horizontal/slant wells, using a PC. In addition to detailed explanations of input data file preparation for simulation runs, special features of BOAST-VHS are described and three sample problems are presented. BOAST-VHS is a cost-effective and easy-to-use reservoir simulation tool for the study of oil production from primary depletion and waterflooding in a black oil reservoir. The well model in BOAST-VHS permits specification of any combination of horizontal, slanted, and vertical wells in the reservoir. BOAST-VHS was designed for an IBM PC/AT, PS-2, or compatible computer with 640 K bytes of memory. BOAST-VHS can be used to model a three-dimensional reservoir of up to 810 grid blocks with any combination of rows, columns, and layers, depending on the input data supplied. This dynamic redimensioning feature facilitates simulation work by avoiding the need to recompiling the simulator for different reservoir models. Therefore the program is only supplied as executable code without any source code.

  16. PC-based Multiple Information System Interface (PC/MISI) detailed design and implementation plan

    Science.gov (United States)

    Dominick, Wayne D. (Editor); Hall, Philip P.

    1985-01-01

    The design plan for the personal computer multiple information system interface (PC/MISI) project is discussed. The document is intended to be used as a blueprint for the implementation of the system. Each component is described in the detail necessary to allow programmers to implement the system. A description of the system data flow and system file structures is given.

  17. Synthesis, Characterization, and Evaluation of Boron-Doped Iron Oxides for the Photocatalytic Degradation of Atrazine under Visible Light

    Directory of Open Access Journals (Sweden)

    Shan Hu

    2012-01-01

    Full Text Available Photocatalytic degradation of atrazine by boron-doped iron oxides under visible light irradiation was investigated. In this work, boron-doped goethite and hematite were successfully prepared by sol-gel method with trimethylborate as boron precursor. The powders were characterized by XRD, UV-vis diffuse reflectance spectra, and porosimetry analysis. The results showed that boron doping could influence the crystal structure, enlarge the BET surface area, improve light absorption ability, and narrow their band-gap energy. The photocatalytic activity of B-doped iron oxides was evaluated in the degradation of atrazine under the visible light irradiation, and B-doped iron oxides showed higher atrazine degradation rate than that of pristine iron oxides. Particularly, B-doped goethite exhibited better photocatalytic activity than B-doped hematite.

  18. Atrazine and nitrate in drinking water and the risk of preterm delivery and low birth weight in four Midwestern states

    DEFF Research Database (Denmark)

    Stayner, Leslie Thomas; Almberg, Kirsten; Jones, Rachael

    2017-01-01

    Background: Atrazine and nitrate are common contaminants in water, and there is limited evidence that they are associated with adverse birth outcomes. The objective of this study was to examine whether atrazine and nitrate in water are associated with an increased risk of preterm delivery (PTD.......95 ppm) were generally low. Neither contaminant was associated with an increased risk of term LBW. Atrazine exposure was associated with a significant increased rate of PTD when well use was restricted to 10% and the exposure was averaged over 4–6 months prior to birth (Rate Ratio for 1 ppm increase [RR1...... study need to be interpreted cautiously given its ecologic design, and limitations in the data for the exposures and other risk factors. Nonetheless, our findings do raise concerns about the potential adverse effects of these common water contaminants on human development and health, and the adequacy...

  19. Variation in the response of the invasive species Potamopyrgus antipodarum (Smith) to natural (cyanobacterial toxin) and anthropogenic (herbicide atrazine) stressors

    Energy Technology Data Exchange (ETDEWEB)

    Gerard, Claudia [UMR CNRS Ecobio 6553, Equipe Physiologie et Ecophysiologie, Universite de Rennes 1, Avenue du General Leclerc, 35042 Rennes cedex (France)]. E-mail: claudia.gerard@univ-rennes1.fr; Poullain, Virginie [UMR CNRS Ecobio 6553, Equipe Physiologie et Ecophysiologie, Universite de Rennes 1, Avenue du General Leclerc, 35042 Rennes cedex (France)

    2005-11-15

    In the context of increasing freshwater pollution, the impact on life-traits (survival, growth and fecundity) and locomotion of Potamopyrgus antipodarum of a 5-week field-concentration exposure to the cyanobacterial toxin microcystin-LR and the triazine herbicide, atrazine was studied. Whatever the age of exposed snails (juveniles, subadults, adults), microcystin-LR induced a decrease in survival, growth and fecundity but had no effect on locomotion. Atrazine induced a decrease in locomotory activity but had no significant effect on the life-traits. These results are discussed in terms of consequences to field populations. - At concentrations relevant to the field, cyanobacterial toxins (natural) and atrazine (anthropogenic) are detrimental to the gastropod Potamopyrgus antipodarum, with a greater toxicity for the natural (vs anthropogenic) stressor.

  20. The white dwarf population within 40 pc of the Sun

    CERN Document Server

    Torres, S

    2016-01-01

    The white dwarf luminosity function is an important tool to understand the properties of the Solar neighborhood, like its star formation history, and its age. Here we present a population synthesis study of the white dwarf population within 40~pc from the Sun, and compare the results of this study with the properties of the observed sample. We use a state-of-the-art population synthesis code based on Monte Carlo techniques, that incorporates the most recent and reliable white dwarf cooling sequences, an accurate description of the Galactic neighborhood, and a realistic treatment of all the known observational biases and selection procedures. We find a good agreement between our theoretical models and the observed data. In particular, our simulations reproduce a previously unexplained feature of the bright branch of the white dwarf luminosity function, which we argue is due to a recent episode of star formation. We also derive the age of the Solar neighborhood employing the position of the observed cut-off of ...

  1. Assessing Watershed Transport of Atrazine and Nitrate to Evaluate Conservation Practice Effects and Advise Future Monitoring Strategies

    Science.gov (United States)

    O'Donnell, T. Kevin

    2012-01-01

    Continued public support for U.S. taxpayer funded programs aimed at reducing agricultural pollutants depends on clear demonstrations of water quality improvements. The objective of this research was to determine if implementation of agricultural best management practices (BMPs) in the Goodwater Creek Experimental Watershed (GCEW) resulted in changes to atrazine and nitrate (NO3-N) loads during storm events. An additional objective was to estimate future monitoring periods necessary to detect a 5, 10, 20, and 25% reduction in atrazine and NO3-N event load. The GCEW is a 73 km2 watershed located in northcentral Missouri, USA. Linear regressions and Akaike Information Criteria were used to determine if reductions in atrazine and NO3-N event loads occurred as BMPs were implemented. No effects due to any BMP type were indicated for the period of record. Further investigation of event sampling from the long-term GCEW monitoring program indicated errors in atrazine load calculations may be possible due to pre-existing minimum threshold levels used to trigger autosampling and sample compositing. Variation of event loads was better explained by linear regressions for NO3-N than for atrazine. Decommissioning of upstream monitoring stations during the study period represented a missed opportunity to further explain variation of event loads at the watershed outlet. Atrazine requires approximately twice the monitoring period relative to NO3-N to detect future reductions in event load. Appropriate matching of pollutant transport mechanisms with autosampling protocols remains a critical information need when setting up or adapting watershed monitoring networks aimed at detecting watershed-scale BMP effects.

  2. Quantitative assessment of mammary gland development in female Long Evans rats following in utero exposure to atrazine.

    Science.gov (United States)

    Hovey, Russell C; Coder, Pragati Sawhney; Wolf, Jeffrey C; Sielken, Robert L; Tisdel, Merrill O; Breckenridge, Charles B

    2011-02-01

    In this study, we quantified the effects of in utero exposure to the herbicide atrazine on subsequent mammary gland development. Atrazine was administered to pregnant female Long Evans rats from gestation days 13-19 at doses of 0, 6.5, 50, or 100 mg/kg/day. A pair-fed control group was yoked to the high-dose atrazine-treated group. Litter size was standardized to 10 pups on postnatal day (PND) 4. Whole mounts of the left fourth mammary gland and histologic sections of the right fourth gland were obtained from a subgroup of offspring on PND1, 21, 33, on day of vaginal opening (VO), or around PND65 at diestrus. A blinded, quantitative analysis of key morphological features in mammary gland whole mounts (ductal elongation, ductal network area, epithelial area, terminal end bud [TEB] incidence, and epithelial density) as well as epithelial proliferation within different parenchymal structures was conducted. There was no effect of atrazine exposure on any of the measures of mammary gland development at the maternal dose of 6.5 mg/kg/day. On PND1, ductal elongation was increased by approximately 20% (p < 0.05) in the female offspring born to dams exposed to 50 and 100 mg/kg/day atrazine, coincident with decreased epithelial proliferation in the 100 mg/kg/day group at this age. These differences were not present on PND21, or thereafter. An increased incidence of TEB in the mammary glands from females that were born to both the pair-fed and 50 mg/kg/day-treated dams at the time of VO indicated that this response was a specific result of maternal caloric restriction. Collectively, these data indicate that maternal atrazine exposure has no long-term effects on mammary gland development in female offspring beyond a transitory response to high doses at PND1.

  3. Efficient degradation of atrazine by magnetic porous copper ferrite catalyzed peroxymonosulfate oxidation via the formation of hydroxyl and sulfate radicals.

    Science.gov (United States)

    Guan, Ying-Hong; Ma, Jun; Ren, Yue-Ming; Liu, Yu-Lei; Xiao, Jia-Yue; Lin, Ling-qiang; Zhang, Chen

    2013-09-15

    Magnetic porous copper ferrite (CuFe2O4) showed a notable catalytic activity to peroxymonosulfate (PMS). More than 98% of atrazine was degraded within 15 min at 1 mM PMS and 0.1 g/L CuFe2O4. In contrast, CuFe2O4 exhibited no obvious catalytic activity to peroxodisulfate or H2O2. Several factors affecting the catalytic performance of PMS/CuFe2O4 were investigated. Results showed that the catalytic degradation efficiency of atrazine increased with PMS and CuFe2O4 doses, but decreased with the increase of natural organic matters concentration. The catalytic oxidation also showed a dependence on initial pH. The presence of bicarbonate stimulated atrazine degradation by PMS/CuFe2O4 at low concentrations but inhibited the degradation at high concentrations. Furthermore, the reactive species for atrazine degradation in PMS/CuFe2O4 system were identified as hydroxyl radical (HO) and sulfate radical (SO4(·-)) through competition reactions of atrazine and nitrobenzene, instead of commonly used alcohol scavenging, which was not a reliable method in metal oxide catalyzed oxidation. Surface hydroxyl groups of CuFe2O4 were a critical part in radical generation and the copper on CuFe2O4 surface was an active site to catalyze PMS. The catalytic degradation of atrazine by PMS/CuFe2O4 was also effective under the background of actual waters.

  4. A MEMS stronglink with multi-try function used for PC startup in authentication system

    Institute of Scientific and Technical Information of China (English)

    LI Sheng-yong; CHEN Wen-yuan; ZHANG Wei-ping; XIAO Qi-jun; TAN Shun-yi; FENG Min-hua

    2009-01-01

    The stronglink with multi-try function based on MEMS technology and the PC startup in authentication system have been designed and fabricated. The generation principle and structure of UQS code are introduced, which consists of two groups of metal counter-meshing gears, two pawl/ratchet mechanisms, two driving micromotors and two resetting micromotors. The energy-coupling element is a photoelectric sensor with a circular and notched plate. It is fabricated using the UV-LiGA process and precision mechanical engineering. The PC startup authentication system is controlled by BIOS program, which is written into the chip according with special format. The program in BIOS output signals controls the running of stronglink to finish the process of authentication. The device can run more than 10000 times before a stop. The driving voltage is 12 V, and the normal decoding time is 3 s.

  5. Graphical programming harnesses multicore PC technology

    Institute of Scientific and Technical Information of China (English)

    National Instruments

    2007-01-01

    @@ Multicore processing is generating considerable buzz within the PC industry,largely because both Intel and AMD have released initial versions of their own multicore processors.These first multicore processors contain two cores,or computing engines,located in one physical processor-hence the name dual-core processors.Processors with more than two cores also are on the horizon.Dualcore processors can simultaneously execute two computing tasks.This is advantageous in multitasking environments,such as Windows XP,in which you simultaneously run multiple applications.Two applications-National instruments LabVIEW and Microsoft Excel,for exampleeach can access a separate processor core at the same time,thus improving overall performance for applications such as data logging.

  6. Pachyonychia congenita with late onset (PC tarda

    Directory of Open Access Journals (Sweden)

    A Sravanthi

    2016-01-01

    Full Text Available Pachyonychia congenita is a rare type of ectodermal dysplasia further classified into 4 types. Cutaneous manifestations seen in most of the cases of Pachyonychia congenita include palmoplantar keratoderma, follicular hyperkeratosis, wedge shaped nails, oral leukokeratosis and woolly hair. A 25-year-old male presented to us with thickened nails and scanty scalp hair. On examination, we noticed hyperkeratotic plaques over both the soles, palmoplantar hyperhidrosis and yellowish discoloration, wedging with subungual hyperkeratosis of all the nails. Follicular hyperkeratotic papules and steatocystoma multiplex were also observed over the scalp and face. The patient had history of natal teeth and on dental examination, lower central incisors were absent. All cutaneous changes in our case had manifested first in the 2nd decade except for natal teeth. All the above features suggested the diagnosis of pachyonychia congenita with late onset (PC tarda, which is an infrequently reported rare variant.

  7. Atrazine is primarily responsible for the toxicity of long-term exposure to a combination of atrazine and inorganic arsenic in the nigrostriatal system of the albino rat.

    Science.gov (United States)

    Bardullas, Ulises; Giordano, Magda; Rodríguez, Verónica Mireya

    2013-01-01

    Chronic and simultaneous exposure to a variety of chemicals present in the environment is an unavoidable fact. However, given the complexity of studying chemical mixtures, most toxicological studies have focused on the effects of short-term exposure to single substances. The aim of this study was to evaluate the effects on the nigrostriatal system of the chronic, simultaneous exposure to two widely distributed substances that have been identified as potential dopaminergic system toxicants, inorganic arsenic (iAs) and atrazine (ATR). Six groups of rats were treated daily for one year with atrazine (10mg ATR/kg), inorganic arsenic (0.5 or 50mgiAs/L of drinking water), or a combination of ATR+0.5mgiAs/L or ATR+50mgiAs/L. The 50mgiAs/L group showed locomotor hypoactivity, while all treatments decreased motor coordination in contrast no effects of treatment were found on the place and response learning tasks. Regarding markers for liver and muscle damage, there were no differences between groups in creatine kinase (CK) or aspartate transaminase (AST) activities, while decreases in lactate dehydrogenase (LDH) levels were found in some exposed groups. The striatal DA content was significantly reduced in ATR, 0.5mgiAs/L, ATR+0.5mgiAs/L, and ATR+50mgiAs/L groups, in comparison to the control group. The number of mesencephalic tyrosine hydroxylase positive cells decreased in the ATR and ATR+0.5mgiAs/L groups compared to the control. In contrast, immunoreactivity to cytochrome oxidase was reduced compared to the control in all treated groups, except for the group treated with 0.5iAsmg alone. Our results indicate that ATR has deleterious effects on dopaminergic neurons and that the combination of ATR and iAs does not exacerbate these effects.

  8. A study of Pc-5 ULF oscillations

    Directory of Open Access Journals (Sweden)

    M. K. Hudson

    2004-01-01

    Full Text Available A study of Pc-5 magnetic pulsations using data from the Combined Release and Radiation Effects Satellite (CRRES was carried out. Three-component dynamic magnetic field spectrograms have been used to survey ULF pulsation activity for the approximate fourteen month lifetime of CRRES. Two-hour panels of dynamic spectra were examined to find events which fall into two basic categories: 1 toroidal modes (fundamental and harmonic resonances and 2 poloidal modes, which include compressional oscillations. The occurence rates were determined as a function of L value and local time. The main result is a comparable probability of occurence of toroidal mode oscillations on the dawn and dusk sides of the magnetosphere inside geosynchronous orbit, while poloidal mode oscillations occur predominantly along the dusk side, consistent with high azimuthal mode number excitation by ring current ions.

    Pc-5 pulsations following Storm Sudden Commencements (SSCs were examined separately. The spatial distribution of modes for the SSC events was consistent with the statistical study for the lifetime of CRRES. The toroidal fundamental (and harmonic resonances are the dominant mode seen on the dawn-side of the magnetosphere following SSCs. Power is mixed in all three components. In the 21 dusk side SSC events there were only a few examples of purely compressional (two or radial (one power in the CRRES study, a few more examples of purely toroidal modes (six, with all three components predominant in about half (ten of the events.

    Key words. Magnetospheric physics (MHD waves and instabilities; magnetospheric configuration and dynamics – Space plasma physics (waves and instabilities

  9. Effect of Dissolved Humic Substances on the Photochemical Degradation Rate of 1-Aminopyrene and Atrazine

    Directory of Open Access Journals (Sweden)

    Hongtao Yuzuri

    2002-10-01

    Full Text Available Abstract: Humic substances (HS are ubiquitous in the environment, and can act as photosensitizers in the redox reactions of some photochemical processes. The influence of HS in these reactions varies with the HS type and concentration. The total organic carbon content (TOC of some commercial HS (such as soil and river humic acid, and fulvic acid was studied. 1-Aminopyrene (1-AP and 1-hydoxypyrene (1-HP are carcinogenic and slightly water-soluble polycyclic aromatic hydrocarbons (PAH. The impact of PAH on natural environment is related to their photolysis rates and photoproducts; therefore, it is of interest to study the photolysis of these compounds. Our previous study showed that the photolysis rate of 1-HP was inhibited by HS. In this study, photolysis of 1-AP was conducted with pure water, natural river water, and pure water containing commercial HS. It was found that the photolysis rate of 1-AP can be inhibited or enhanced by HS, depending on the type and concentration. The first order photolysis rate constant of 1-AP (10 μM in phosphate buffer (pH 7.0, 1 mM containing a humic acid (20-80 ppm was enhanced by up to 5 folds. With a fulvic acid (20-80 ppm, it was enhanced by about 2 folds. With a soil humic acid, it was enhanced by about 2 folds at the concentration of 20 ppm and was inhibited by up to 4 folds at the concentration of 80 ppm. Atrazine (2-chloro-4-ethylamine-6-isopropylamino-s-triazine is a widely used herbicide. It is toxic, often bioaccumulative and persistent. In this study, the effect of HS on the photochemical fate of atrazine was also studied. The results showed that photolysis of atrazine can be enhanced by humic acid, depending on the type and concentration of humic acid. The fulvic acid has no effect on its photolysis within 10 days.

  10. Effects of atrazine, metolachlor, carbaryl and chlorothalonil on benthic microbes and their nutrient dynamics.

    Directory of Open Access Journals (Sweden)

    Daniel Elias

    Full Text Available Atrazine, metolachlor, carbaryl, and chlorothalonil are detected in streams throughout the U.S. at concentrations that may have adverse effects on benthic microbes. Sediment samples were exposed to these pesticides to quantify responses of ammonium, nitrate, and phosphate uptake by the benthic microbial community. Control uptake rates of sediments had net remineralization of nitrate (-1.58 NO3 µg gdm⁻¹ h⁻¹, and net assimilation of phosphate (1.34 PO4 µg gdm⁻¹ h⁻¹ and ammonium (0.03 NH4 µg gdm⁻¹ h⁻¹. Metolachlor decreased ammonium and phosphate uptake. Chlorothalonil decreased nitrate remineralization and phosphate uptake. Nitrate, ammonium, and phosphate uptake rates are more pronounced in the presence of these pesticides due to microbial adaptations to toxicants. Our interpretation of pesticide availability based on their water/solid affinities supports no effects for atrazine and carbaryl, decreasing nitrate remineralization, and phosphate assimilation in response to chlorothalonil. Further, decreased ammonium and phosphate uptake in response to metolachlor is likely due to affinity. Because atrazine target autotrophs, and carbaryl synaptic activity, effects on benthic microbes were not hypothesized, consistent with results. Metolachlor and chlorothalonil (non-specific modes of action had significant effects on sediment microbial nutrient dynamics. Thus, pesticides with a higher affinity to sediments and/or broad modes of action are likely to affect sediment microbes' nutrient dynamics than pesticides dissolved in water or specific modes of action. Predicted nutrient uptake rates were calculated at mean and peak concentrations of metolachlor and chlorothalonil in freshwaters using polynomial equations generated in this experiment. We concluded that in natural ecosystems, peak chlorothalonil and metolachlor concentrations could affect phosphate and ammonium by decreasing net assimilation, and nitrate uptake rates by

  11. Histological Studies of Atrazine Toxicity on the Thyroid Gland in Rats

    Institute of Scientific and Technical Information of China (English)

    I.N.KORNILOVSKAYA; M.V.GORELAYA; 等

    1996-01-01

    Little is known about the toxic activity of the atrazine(a herbicide,commonly used in agricultural production)on the thyroid gland.In this study the compound was administered orally in female albino rats at subletal exposure equivalent to 0.2 LD50 doses for 6 and 12 days.At termination of dosing the anesthetized animals were killed and blood was drawn fo the determination of serum triiodothyronine(T3)and thyroxin(T4).A dose-dependent decrease of serum T3 concentration was observed in all the groups (control:0.5nmol·L-1,6days:0.35nmol·L-1,12days:0.21nmol·L-1).The thyroid gland was examined light-microscopically.Bouin's solution-fixed thyroids were embedded in paraffin and sections cut at 6μm ,stained separately with toluidine blue according to Slinchenko's method.Histologically in experimental groups epithelium featured small cuboidal cells and occasional structures of the follicles confluence within epitheliomers.A dose-dependent changes of the following parameters were observed:(a)increasing of number of follicle-building thyroid cells;(b) increasing of tollicular volume;(c) decreasing of nucleus volume.Investigation of the whole population of thyroid mast cells disclosed no change in degranulation intensity.By contrast,Degranulation intensity was decreased in perifollicular mast cells from groups treated with atrazine in dose-dependent manner.There are no changes observed in degranulation of stromal mast cells.These results suggesting that differences in response to the atrazine might account for an aspect of the functional heterogeneit within the rat thyroid mast cell population.

  12. Dissolved nutrients and atrazine removal by column-scale monophasic and biphasic rain garden model systems.

    Science.gov (United States)

    Yang, Hanbae; McCoy, Edward L; Grewal, Parwinder S; Dick, Warren A

    2010-08-01

    Rain gardens are bioretention systems that have the potential to reduce peak runoff flow and improve water quality in a natural and aesthetically pleasing manner. We compared hydraulic performance and removal efficiencies of nutrients and atrazine in a monophasic rain garden design versus a biphasic design at a column-scale using simulated runoff. The biphasic rain garden was designed to increase retention time and removal efficiency of runoff pollutants by creating a sequence of water saturated to unsaturated conditions. We also evaluated the effect of C substrate availability on pollutant removal efficiency in the biphasic rain garden. Five simulated runoff events with various concentrations of runoff pollutants (i.e. nitrate, phosphate, and atrazine) were applied to the monophasic and biphasic rain gardens once every 5d. Hydraulic performance was consistent over the five simulated runoff events. Peak flow was reduced by approximately 56% for the monophasic design and 80% for the biphasic design. Both rain garden systems showed excellent removal efficiency of phosphate (89-100%) and atrazine (84-100%). However, significantly (p<0.001) higher removal of nitrate was observed in the biphasic (42-63%) compared to the monophasic rain garden (29-39%). Addition of C substrate in the form of glucose increased removal efficiency of nitrate significantly (p<0.001), achieving up to 87% removal at a treatment C/N ratio of 2.0. This study demonstrates the importance of retention time, environmental conditions (i.e. saturated/unsaturated conditions), and availability of C substrate for bioremediation of pollutants, especially nitrates, in rain gardens.

  13. Effects of atrazine in fish, amphibians, and reptiles: an analysis based on quantitative weight of evidence.

    Science.gov (United States)

    Van Der Kraak, Glen J; Hosmer, Alan J; Hanson, Mark L; Kloas, Werner; Solomon, Keith R

    2014-12-01

    A quantitative weight of evidence (WoE) approach was developed to evaluate studies used for regulatory purposes, as well as those in the open literature, that report the effects of the herbicide atrazine on fish, amphibians, and reptiles. The methodology for WoE analysis incorporated a detailed assessment of the relevance of the responses observed to apical endpoints directly related to survival, growth, development, and reproduction, as well as the strength and appropriateness of the experimental methods employed. Numerical scores were assigned for strength and relevance. The means of the scores for relevance and strength were then used to summarize and weigh the evidence for atrazine contributing to ecologically significant responses in the organisms of interest. The summary was presented graphically in a two-dimensional graph which showed the distributions of all the reports for a response. Over 1290 individual responses from studies in 31 species of fish, 32 amphibians, and 8 reptiles were evaluated. Overall, the WoE showed that atrazine might affect biomarker-type responses, such as expression of genes and/or associated proteins, concentrations of hormones, and biochemical processes (e.g. induction of detoxification responses), at concentrations sometimes found in the environment. However, these effects were not translated to adverse outcomes in terms of apical endpoints. The WoE approach provided a quantitative, transparent, reproducible, and robust framework that can be used to assist the decision-making process when assessing environmental chemicals. In addition, the process allowed easy identification of uncertainty and inconsistency in observations, and thus clearly identified areas where future investigations can be best directed.

  14. User`s guide and documentation manual for ``PC-Gel`` simulator

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Ming-Ming; Gao, Hong W.

    1993-10-01

    PC-GEL is a three-dimensional, three-phase (oil, water, and gas) permeability modification simulator developed by incorporating an in-situ gelation model into a black oil simulator (BOAST) for personal computer application. The features included in the simulator are: transport of each chemical species of the polymer/crosslinker system in porous media, gelation reaction kinetics of the polymer with crosslinking agents, rheology of the polymer and gel, inaccessible pore volume to macromolecules, adsorption of chemical species on rock surfaces, retention of gel on the rock matrix, and permeability reduction caused by the adsorption of polymer and gel. The in-situ gelation model and simulator were validated against data reported in the literature. The simulator PC-GEL is useful for simulating and optimizing any combination of primary production, waterflooding, polymer flooding, and permeability modification treatments. A general background of permeability modification using crosslinked polymer gels is given in Section I and the governing equations, mechanisms, and numerical solutions of PC-GEL are given in Section II. Steps for preparing an input data file with reservoir and gel-chemical transport data, and recurrent data are described in Sections III and IV, respectively. Example data inputs are enclosed after explanations of each input line to help the user prepare data files. Major items of the output files are reviewed in Section V. Finally, three sample problems for running PC-GEL are described in Section VI, and input files and part of the output files of these problems are listed in the appendices. For the user`s reference a copy of the source code of PC-GEL computer program is attached in Appendix A.

  15. Characteristics of CoPc/CdS hybrid diode device

    Indian Academy of Sciences (India)

    Murat Çalişkan; Serço Serkis Yeşilkaya; Mevlüde Canlica

    2015-09-01

    CdS/CoPc hybrid heterojunctions were fabricated and characterized. CdS films were deposited by the spray pyrolysis technique on indium tin oxide (ITO)-coated glass substrates and CoPc films coated on CdS by chemical precipitation. Ag contact metal deposited on CoPc by e-beam evaporation and glass/ITO/CdS/ CoPc/Ag structures were fabricated. Rectification ratio, ideality factor, barrier height and junction parameters of the devices were determined. It is shown that device has diode characteristics with the ideality factor (n) of 4.8, rectification ratio of 4.5 and the built-in voltage (b) of 0.48 V. Absorption energy for CoPc was found as 1.57 eV. The results encourage utilizing CoPc as absorber organic material for solar cells.

  16. PC/ABS及PC/ABS/PE-g-MAH共混体系相容性的研究%Compatibility of PC/ABS and PC/ABS/PE-g-MAH Blends

    Institute of Scientific and Technical Information of China (English)

    唐颂超; 蒋丽霞; 周达飞

    2000-01-01

    研究了聚碳酸酯与ABS(PC/ABS)及PC/ABS与马来酸酐接枝聚乙烯共聚物(PC/ABS/PE-g-MAH)共混体系的力学性能和应力开裂性能.用D SC和SEM研究了共混体系的相容性.结果表明:ABS的加入能提高PC的冲击强度,ABS的含量及品种影响PC/ABS合金的力学性能,ABS能提高PC的耐溶剂应力开裂性能.PC/ABS/PE-g-M AH共混体系的力学性能和相容性优于PC/ABS共混体系,PE-g-MAH起到了增容剂的作用.

  17. Genetic algorithms with permutation coding for multiple sequence alignment.

    Science.gov (United States)

    Ben Othman, Mohamed Tahar; Abdel-Azim, Gamil

    2013-08-01

    Multiple sequence alignment (MSA) is one of the topics of bio informatics that has seriously been researched. It is known as NP-complete problem. It is also considered as one of the most important and daunting tasks in computational biology. Concerning this a wide number of heuristic algorithms have been proposed to find optimal alignment. Among these heuristic algorithms are genetic algorithms (GA). The GA has mainly two major weaknesses: it is time consuming and can cause local minima. One of the significant aspects in the GA process in MSA is to maximize the similarities between sequences by adding and shuffling the gaps of Solution Coding (SC). Several ways for SC have been introduced. One of them is the Permutation Coding (PC). We propose a hybrid algorithm based on genetic algorithms (GAs) with a PC and 2-opt algorithm. The PC helps to code the MSA solution which maximizes the gain of resources, reliability and diversity of GA. The use of the PC opens the area by applying all functions over permutations for MSA. Thus, we suggest an algorithm to calculate the scoring function for multiple alignments based on PC, which is used as fitness function. The time complexity of the GA is reduced by using this algorithm. Our GA is implemented with different selections strategies and different crossovers. The probability of crossover and mutation is set as one strategy. Relevant patents have been probed in the topic.

  18. Effects of pulsed atrazine exposures on autotrophic community structure, biomass, and production in field-based stream mesocosms.

    Science.gov (United States)

    King, Ryan S; Brain, Richard A; Back, Jeffrey A; Becker, Christopher; Wright, Moncie V; Djomte, Valerie Toteu; Scott, W Casan; Virgil, Steven R; Brooks, Bryan W; Hosmer, Alan J; Chambliss, C Kevin

    2016-03-01

    The authors performed a multiple-pulsed atrazine experiment to measure responses of autotrophic endpoints in outdoor stream mesocosms. The experiment was designed to synthetically simulate worst-case atrazine chemographs from streams in agricultural catchments to achieve 60-d mean concentrations of 0 μg/L (control), 10 μg/L, 20 μg/L, and 30 μg/L. The authors dosed triplicate streams with pulses of 0 μg/L, 50 μg/L, 100 μg/L, and 150 μg/L atrazine for 4 d, followed by 7 d without dosing. This 11-d cycle occurred 3 times, followed by a recovery (untreated) period from day 34 to day 60. Mean ± standard error 60-d atrazine concentrations were 0.07 ± 0.03 μg/L, 10.7 ± 0.05 μg/L, 20.9 ± 0.24 μg/L, and 31.0 ± 0.17 μg/L for the control, 10-μg/L, 20-μg/L, and 30-μg/L treatments, respectively. Multivariate analyses revealed that periphyton and phytoplankton community structure did not differ among treatments on any day of the experiment, including during the atrazine pulses. Control periphyton biomass in riffles was higher immediately following the peak of the first atrazine pulse and remained slightly higher than some of the atrazine treatments on most days through the peak of the last pulse. However, periphyton biomass was not different among treatments at the end of the present study. Phytoplankton biomass was not affected by atrazine. Metaphyton biomass in pools was higher in the controls near the midpoint of the present study and remained higher on most days for the remainder of the study. Ceratophyllum demersum, a submersed macrophyte, biomass was higher in controls than in 20-μg/L and 30-μg/L treatments before pulse 3 but was not different subsequent to pulse 3 through the end of the present study. Maximum daily dissolved oxygen (DO, percentage of saturation) declined during each pulse in approximate proportion to magnitude of dose but rapidly converged among treatments after the third pulse. However

  19. Space Time Codes from Permutation Codes

    CERN Document Server

    Henkel, Oliver

    2006-01-01

    A new class of space time codes with high performance is presented. The code design utilizes tailor-made permutation codes, which are known to have large minimal distances as spherical codes. A geometric connection between spherical and space time codes has been used to translate them into the final space time codes. Simulations demonstrate that the performance increases with the block lengths, a result that has been conjectured already in previous work. Further, the connection to permutation codes allows for moderate complex en-/decoding algorithms.

  20. Fundamentals of convolutional coding

    CERN Document Server

    Johannesson, Rolf

    2015-01-01

    Fundamentals of Convolutional Coding, Second Edition, regarded as a bible of convolutional coding brings you a clear and comprehensive discussion of the basic principles of this field * Two new chapters on low-density parity-check (LDPC) convolutional codes and iterative coding * Viterbi, BCJR, BEAST, list, and sequential decoding of convolutional codes * Distance properties of convolutional codes * Includes a downloadable solutions manual

  1. Comparison Studies of Dielectric and AC Conduction of PbPc and CuPc Thin Films

    Directory of Open Access Journals (Sweden)

    S. Sivamalar

    2012-08-01

    Full Text Available The thin film of Lead Phthalocyanine (PbPc and Copper Phthalocyanine (CuPc on glass are prepared by Vacuum deposition method. Deposition of PbPc and CuPc on pre-cleaned glass substrates under the pressure of 10-6 Torr are achieved by slowly varying current of 20 Volt. The rate of evaporation is properly controlled and maintained constant during all the evaporations. The thicknesses of the films are 150 nm, 300 nm and 450 nm on glass substrate. Dielectric and AC conduction studies of Lead Phthalocyanine and Cupper Phthalocyanine thin films have been studied. The variations of capacitance with frequency at different, permittivity with temperature, capacitance with temperature and ac conductance with frequency at different temperatures of PbPc and CuPc have been studied. The activation energies have been determined from the slope of 1000/T vs. log Gp curves at different frequencies (where Gp= -Eg/RT.

  2. Application of PC-ANN and PC-LS-SVM in QSAR of CCR1 antagonist compounds: a comparative study.

    Science.gov (United States)

    Shahlaei, Mohsen; Fassihi, Afshin; Saghaie, Lotfollah

    2010-04-01

    Principal component regression (PCR), principal component-artificial neural network (PC-ANN), and principal component-least squares-support vector machine (PC-LS-SVM) as regression methods were investigated for building quantitative structure-activity relationships for the prediction of inhibitory activity of some CCR1 antagonists. Nonlinear methods (PC-ANN and PC-LS-SVM) were better than the PCR method considerably in the goodness of fit and predictivity parameters and other criteria for evaluation of the proposed model. These results reflect a nonlinear relationship between the principal components obtained from molecular descriptors and the inhibitory activity of this set of molecules. The maximum variance in activity of the molecules, in PCR method was 45.5%, whereas nonlinear methods, PC-ANN and PC-LS-SVM, could explain more than 93.7% and 95.6% variance in activity data respectively.

  3. Seasonal detection of atrazine and atzA in man-made waterways receiving agricultural runoff in a subtropical, semi-arid environment (Hidalgo County, Texas, USA).

    Science.gov (United States)

    Cortez, Ibdanelo; Vitek, Christopher J; Persans, Michael W; Lowe, Kristine L

    2017-02-01

    Atrazine is a widely-used herbicide that can impact non-target organisms in the environment but can be biologically degraded by several types of microorganisms. In this study, the gene atzA, which encodes for the initial step in bacterially-mediated atrazine degradation, was used as an indicator of atrazine pollution in agricultural canals located in Hidalgo County, Texas, USA. The concentration of atrazine and atzA were monitored once per month for 12 months during 2010-2011. Atrazine was measured using an enzyme-linked immunosorbent assay; atzA abundance was monitored using Quantitative Polymerase Chain Reaction (Q-PCR) analyses. Abundance of atrazine and atzA were compared with rainy versus dry months and during planting versus non-planting months. Results showed that atrazine levels varied from below detection to 0.43 ppb and were not influenced by precipitation or planting season. Concentrations of the gene atzA were significantly different in rainy versus dry months; during planting versus non-planting times of the year; and in the interaction of precipitation and planting season. The highest concentration of atzA, approx. 4.57 × 10(8) gene copies ml(-1), was detected in July 2010-a rainy, planting month in Hidalgo County, South Texas. However, atrazine was below detection during that month. We conclude that Q-PCR using atzA as an indicator gene is a potential method for monitoring low levels of atrazine pollution in environmental samples.

  4. Strong Trinucleotide Circular Codes

    Directory of Open Access Journals (Sweden)

    Christian J. Michel

    2011-01-01

    Full Text Available Recently, we identified a hierarchy relation between trinucleotide comma-free codes and trinucleotide circular codes (see our previous works. Here, we extend our hierarchy with two new classes of codes, called DLD and LDL codes, which are stronger than the comma-free codes. We also prove that no circular code with 20 trinucleotides is a DLD code and that a circular code with 20 trinucleotides is comma-free if and only if it is a LDL code. Finally, we point out the possible role of the symmetric group ∑4 in the mathematical study of trinucleotide circular codes.

  5. New insights into atrazine degradation by cobalt catalyzed peroxymonosulfate oxidation: kinetics, reaction products and transformation mechanisms.

    Science.gov (United States)

    Ji, Yuefei; Dong, Changxun; Kong, Deyang; Lu, Junhe

    2015-03-21

    The widespread occurrence of atrazine in waters poses potential risk to ecosystem and human health. In this study, we investigated the underlying mechanisms and transformation pathways of atrazine degradation by cobalt catalyzed peroxymonosulfate (Co(II)/PMS). Co(II)/PMS was found to be more efficient for ATZ elimination in aqueous solution than Fe(II)/PMS process. ATZ oxidation by Co(II)/PMS followed pseudo-first-order kinetics, and the reaction rate constant (k(obs)) increased appreciably with increasing Co(II) concentration. Increasing initial PMS concentration favored the decomposition of ATZ, however, no linear relationship between k(obs) and PMS concentration was observed. Higher efficiency of ATZ oxidation was observed around neutral pH, implying the possibility of applying Co(II)/PMS process under environmental realistic conditions. Natural organic matter (NOM), chloride (Cl(-)) and bicarbonate (HCO3(-)) showed detrimental effects on ATZ degradation, particularly at higher concentrations. Eleven products were identified by applying solid phase extraction-liquid chromatography-mass spectrometry (SPE-LC/MS) techniques. Major transformation pathways of ATZ included dealkylation, dechlorination-hydroxylation, and alkyl chain oxidation. Detailed mechanisms responsible for these transformation pathways were discussed. Our results reveal that Co(II)/PMS process might be an efficient technique for remediation of groundwater contaminated by ATZ and structurally related s-triazine herbicides.

  6. Degradation of atrazine by microbial consortium in an anaerobic submerged biological filter.

    Science.gov (United States)

    Nasseri, Simin; Baghapour, Mohammad Ali; Derakhshan, Zahra; Faramarzian, Mohammad

    2014-09-01

    Atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) (ATZ) is one of the components of S-triazine. Due to its certain characteristics, ATZ causes pollution in various ecosystems and has been of concern for its probable carcinogenic effects on humans. Researchers have used chemical and physical methods for removing ATZ from the environment. Although these methods are quick, they have not been capable of complete mineralization. Therefore, researchers are looking for methods with lower energy consumption and cost and higher efficiency. In this study, biodegradation of ATZ by microbial consortium was evaluated in the aquatic environment. The present study aimed to evaluate the efficiency of ATZ removal from aqueous environments by using an anaerobic submerged biological filter in four concentration levels of atrazine and three hydraulic retention times. The maximum efficiencies of ATZ and soluble chemical oxygen demand (SCOD) were 51.1 and 45.6%, respectively. There was no accumulation of ATZ in the biofilm and the loss of ATZ in the control reactor was negligible. This shows that ATZ removal in this system was due to biodegradation. Furthermore, the results of modeling showed that the Stover-Kincannon model had desirable fitness (R² > 99%) in loading ATZ in this biofilter.

  7. Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

    Institute of Scientific and Technical Information of China (English)

    GAO Min-ling; DAI Shu-gui; MA Yong-min; ZHANG Pi

    2007-01-01

    Sorption of chlorotoluron in ammonium sulfate.urea and atrazine multi-solutes system was investigated by batch experiments.The results showed application of nitrogen fertilizers to the soil could affeCt the behavior of chlorotoluron.At the same concentration of N,sorption of chlorotoluron decreased as the concentration of atrazine increased on the day O and 6 in soil.respectively.The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water,ammonium sulfate and urea solution for 6 d.That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments.The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system,but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers.That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.

  8. Release of aged 14C-atrazine residues from soil facilitated by dry-wet cycles

    Science.gov (United States)

    Jablonowski, N. D.; Yu, K.; Koeppchen, S.; Burauel, P.

    2012-04-01

    Intermittent dry-wet cycles may have an important effect on soil structure and aged pesticide residues release (1). A laboratory study was conducted to assess the maximum potential of water extractable aged atrazine residues influenced by soil drying and wetting. The used soil was obtained from an outdoor lysimeter (gleyic cambisol; Corg: 1.45%), containing environmentally aged (22 years) 14C-atrazine residues. For the experiment, soil from 0-10 cm depth was used since most residual 14C activity was previously found in this layer (2,3). Triplicate soil samples with a residual water content of approx. 8% were either dried (45° C) prior water addition or directly mixed with distilled water (soil+water: 1+2, w:w). The samples were shaken (150 rmp, 60 min, at 21° C), centrifuged (approx. 2000 g), and the supernatants were filtered. Water-extracted residual 14C activity was detected via liquid scintillation counter. The total water-extracted 14C activity (the amount of residual 14C activity in a sample equals 100%) was significantly higher (p

  9. MOLECULAR IMPRINTED SOLID PHASE EXTRACTION FOR DETERMINATION OF ATRAZINE IN ENVIRONMENTAL SAMPLES

    Directory of Open Access Journals (Sweden)

    A. R. Koohpaei ، S. J. Shahtaheri ، M. R. Ganjali ، A. Rahimi Forushani

    2008-10-01

    Full Text Available Solid phase extraction is one of the major applications of molecularly imprinted polymers fields for clean-up of environmental and biological samples namely molecularly imprinted solid-phase extraction. In this study, solid phase extraction using the imprinted polymer has been optimized with the experimental design approach for a triazine herbicide, named atrazine with regard to the critical factors which influence the molecular imprinted solid phase extraction efficiency such as sample pH, concentration, flow-rate, volume, elution solvent, washing solvent and sorbent mass. Optimization methods that involve changing one factor at a time can be laborious. A novel approach for the optimization of imprinted solid-phase extraction using chemometrics is described. The factors were evaluated statistically and also validated with spiked water samples and showed a good reproducibility over six consecutive days as well as six within-day experiments. Also, in order to the evaluate efficiency of the optimized molecularly imprinted solid-phase extraction protocols, enrichment capacity, reusability and cross-reactivity of cartridges have been also evaluated. Finally, selective molecularly imprinted solid-phase extraction of atrazine was successfully demonstrated with a recovery above 90% for spiked drinking water samples. It was concluded that the chemometrics is frequently employed for analytical method optimization and based on the obtained results, it is believed that the central composite design could prove beneficial for aiding the molecularly imprinted polymer and molecularly imprinted solid-phase extraction development.

  10. Development of Advanced In core Management Codes for Ulchin Unit 1, 2

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Hee; Park, Moon Gyu [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

    1996-12-31

    As the first case of FRAMATOME`s plants, Ulchin Unit 1 Cycle 8 core was loaded with V5H fuel. Because of the heterogeneity in the axial enrichment of the V5H fuel, FRAMATOME`s 2-D in core management codes, CEDRIC-CARIN-ESTHER, are no longer valid to be used for in core management. In order to analyze Ulchin Unit 1 an 2 cores loaded with V5H fuel exactly, this study substituted them with WH`s In core-3D and Tote code. The previous IN CORE-Tote codes have been utilized on the HP workstation or the IBM mainframe which are not easily accessible by the site engineers and require the complicated manipulation in the computer network system. This study developed the PC-version of IN CORE-3D and Tote codes available in plants, including an interface code linking the data measured by the in core instrument system (RIC-KIT system) to IN CORE code. These codes reduce the time to manage in core and increase the economic benefits. We installed the developed codes in Ulchin Unit 1 and 2 and actually applied them to the core power distribution measurement performed during Cycle 8 power escalation tests. The results satisfied all limits of Technical Specification very well. The major contents of this study can be categorized as follows. 1. Analysis of the in core management codes. (a) Analysis of flux mapping system and measurement reduction algorithm. (b) Analysis of the methodology of in core management codes. 2. Development and verification of PC-version in core management codes. (a) Development of the measured-data processing code (C2I). (b) Development of PC-version IN CORE code. (c) Development of PC-version Tote code (d) Verification of the developed codes. 3. Application to core physics test of Ulchin until cycle 8. (a) Power distribution measurement at 75% and 100%. (author). 14 refs., figs., tabs.

  11. Study of Boiling Water Resistant PC/PE Alloy Materials%耐水煮PC/PE合金的研究

    Institute of Scientific and Technical Information of China (English)

    申景强; 刘振华; 诸泉; 蒋文真

    2012-01-01

    采用熔融共混工艺路线,选择合适的PC、PE和增容剂(PE-g-GMA)制备了PC/PE合金材料,研究了PE对PC/PE合金力学性能和热变形温度的影响,以及PC/PE合金经240 h水煮后的缺口冲击强度。结果表明当PE含量为5%时,PC/PE合金的综合物性最佳。%PC/PE alloy was prepared through melt blending process by using PC,PE and compatibilizing agents(PE-g-GMA).The effect of PE on mechanical property and heat deflection temperature of PC/PE alloy were studied and notched impact strength of PC/PE alloy after 240 hours in boiling water was characterized.The result showed that PC/PE alloy containing 5 WT% can achieve the best comprehensive properties.

  12. Organic matter in four Brazilian soil types: chemical composition and atrazine sorption; Materia organica em quatro tipos de solos brasileiros: composicao quimica e sorcao de atrazina

    Energy Technology Data Exchange (ETDEWEB)

    Dick, Deborah Pinheiro [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Inst. de Quimica. Dept. de Fisico-quimica; Martinazzo, Rosane [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Faculdade de Agronomia. Dept. de Solos; Knicker, Heike [Technische Universitaet Muenchen, Freising (Germany). Lehrstuhl fuer Bodenkunde; Almeida, Paulo Sergio Gois [Centro de Ensino Superior de Rondonopolis, MT (Brazil)

    2010-07-01

    Soil organic matter is the main sorptive soil compartment for atrazine in soils, followed in a minor scale by the inorganic fraction. In this study, the soil organic matter quality and atrazine sorption were investigated in four different soil types. The pedogenic environment affected the humification and therefore the chemical composition of the organic matter. The organic matter contribution to atrazine sorption was larger (60-83%) than that of the inorganic fraction. The organic matter capacity in retaining the herbicide was favoured by a higher decomposition degree and a smaller carboxylic substitution of the aliphatic chains. (author)

  13. Degradation of atrazine by a novel Fenton-like process and assessment the influence on the treated soil.

    Science.gov (United States)

    Cheng, Min; Zeng, Guangming; Huang, Danlian; Lai, Cui; Xu, Piao; Zhang, Chen; Liu, Yang; Wan, Jia; Gong, Xiaomin; Zhu, Yuan

    2016-07-15

    This is the premier study reporting the remediation of atrazine contaminated soil with steel converter slag (SCS) catalyzed Fenton-like process. The effects of various operating parameters, such as SCS loads and H2O2 concentrations were evaluated with respect to the removal efficiency of atrazine. Results show the optimal SCS load and H2O2 concentration were 80gkg(-1) and 10%, respectably. The graded modified Fenton's oxidation with a 3-time addition of 10% H2O2 was able to remove 93.7% of total atrazine in the contaminated soil and maintain soil temperature within 50°C. In contrast to traditional Fenton treatment, a slight pH increase has been observed due to the addition of SCS. More importantly, experiment conducted at natural conditions with SCS gave the similar atrazine removal to the experiments with the other catalysts (e.g., FeSO4 and Fe2O3). One thing should be noted that after the treatment, dissolved organic carbon (DOC) content increased to 1.206gkg(-1) from an initial value of 0.339gkg(-1).

  14. Survival and precopulatory guarding behavior of Hyalella azteca (Amphipoda) exposed to nitrate in the presence of atrazine.

    Science.gov (United States)

    Pandey, Ram B; Adams, Ginny L; Warren, Laurie W

    2011-05-01

    Nitrate is one of the most commonly detected contaminants found in aquatic systems with other pesticides such as atrazine. The current study examined potential combined effects of nitrate and atrazine on adults of the freshwater amphipod Hyalella azteca, using survival and precopulatory guarding behavior as toxic endpoints. Although significant differences in acute toxicity with nitrate alone and in binary combination with atrazine (200 µg/L) in water-only tests were not consistently observed for each time point, potential biologically relevant trends in the data were observed. Posttest growth and behavioral observations (10-day period) conducted after 96-hour exposure suggested that atrazine and nitrate at these concentrations did not result in delayed effects on H. azteca. However, when test conditions were modified from standard toxicity tests by feeding amphipods, nitrate was found to be more toxic, with a reduction in median lethal concentration (LC50) values of approximately 80%. We also demonstrated that nitrate exhibits a dose-response effect on precopulatory guarding behavior of H. azteca, suggesting that reproductive effects may occur at environmentally relevant concentrations.

  15. Gestational Atrazine Exposure: Effects on Male Reproductive Development and Metabolite Distribution in the Dam, Fetus, and Neonate

    Science.gov (United States)

    Few studies have investigated the long-term effects of atrazine (ATR)following in utero exposure. We evaluated the effects of gestational exposure of Sprague Dawley dams to ATR (0, 1, 5.20, or 100 mg/Kg-d) on the reproductive development of male offspring. We also quantified the...

  16. Low resistance against novel 2-benzylamino-1,3,5-triazine herbicides in atrazine-resistant Chenopodium album plants

    NARCIS (Netherlands)

    Kohno, H.; Ohki, A.; Koizumi, K.; Noort, van den M.E.; Rodrigues, G.C.; Rensen, van J.J.S.; Wakabayashi, K.

    2000-01-01

    The effects of nine novel 2-benzylamino-1,3,5-triazines on photosynthetic reactions were measured in thylakoids isolated from wild-type and atrazine-resistant plants of Chenopodium album. The resistant plants have a mutation of serine for glycine at position 264 of the D1 protein. The measurement of

  17. Transcriptional profiles of glutathione-S-Transferase isoforms, Cyp, and AOE genes in atrazine-exposed zebrafish embryos.

    Science.gov (United States)

    Glisic, Branka; Hrubik, Jelena; Fa, Svetlana; Dopudj, Nela; Kovacevic, Radmila; Andric, Nebojsa

    2016-02-01

    Glutathione-S-transferase (GST) superfamily consists of multiple members involved in xenobiotic metabolism. Expressional pattern of the GST isoforms in adult fish has been used as a biomarker of exposure to environmental chemicals. However, GST transcriptional responses vary across organs, thus requiring a cross-tissue examination of multiple mRNAs for GST profiling in an animal after chemical exposure. Zebrafish embryos express all GST isoforms as adult fish and could therefore represent an alternative model for identification of biomarkers of exposure. To evaluate such a possibility, we studied a set of cytosolic and microsomal GST isoform-specific expression profiles in the zebrafish embryos after exposure to atrazine, a widely used herbicide. Expression of the GST isoforms was compared with that of CYP genes involved in the phase I of xenobiotic metabolism and antioxidant enzyme (AOE) genes. Using quantitative real-time PCR, we showed dynamic changes in the expressional pattern of twenty GST isoforms, cyp1a, cyp3a65, ahr2, and four AOEs in early development of zebrafish. Acute (48 and 72 h) exposure of 24 h-old embryos to atrazine, from environmentally relevant (0.005 mg/L) to high (40 mg/L) concentrations, caused a variety of transient, albeit minor changes (atrazine (5 and 40 mg/L). In summary, an analysis of the response of multiple systems in the zebrafish embryos provided a comprehensive understanding of atrazine toxicity and its potential impact on biological processes.

  18. The effects of prenatal exposure to atrazine on pubertal and postnatal reproductive indices in the female rat

    Science.gov (United States)

    Atrazine (ATR) is a commonly used herbicide that can exert negative reproductive effects in animals. We examined the effects of vehicle or ATR at 1, 5, 20 and 100 mg/kg/d, administered to Sprague-Dawley rats on gestational days 14-21, once daily or divided into two doses per day,...

  19. Decomposition of atrazine traces in water by combination of non-thermal electrical discharge and adsorption on nanofiber membrane.

    Science.gov (United States)

    Vanraes, Patrick; Willems, Gert; Daels, Nele; Van Hulle, Stijn W H; De Clerck, Karen; Surmont, Pieter; Lynen, Frederic; Vandamme, Jeroen; Van Durme, Jim; Nikiforov, Anton; Leys, Christophe

    2015-04-01

    In recent decades, several types of persistent substances are detected in the aquatic environment at very low concentrations. Unfortunately, conventional water treatment processes are not able to remove these micropollutants. As such, advanced treatment methods are required to meet both current and anticipated maximally allowed concentrations. Plasma discharge in contact with water is a promising new technology, since it produces a wide spectrum of oxidizing species. In this study, a new type of reactor is tested, in which decomposition by atmospheric pulsed direct barrier discharge (pDBD) plasma is combined with micropollutant adsorption on a nanofiber polyamide membrane. Atrazine is chosen as model micropollutant with an initial concentration of 30 μg/L. While the H2O2 and O3 production in the reactor is not influenced by the presence of the membrane, there is a significant increase in atrazine decomposition when the membrane is added. With membrane, 85% atrazine removal can be obtained in comparison to only 61% removal without membrane, at the same experimental parameters. The by-products of atrazine decomposition identified by HPLC-MS are deethylatrazine and ammelide. Formation of these by-products is more pronounced when the membrane is added. These results indicate the synergetic effect of plasma discharge and pollutant adsorption, which is attractive for future applications of water treatment.

  20. Mammary gland development and response to prenatal atrazine exposure in the Sprague Dawley and Long-Evans rats.

    Science.gov (United States)

    Mammary gland (MG) tumor development in Sprague Dawley (SD) rats is increased by longterm dietary exposure to the chlorotriazine herbicide atrazine (ATR). ATR is proposed to cause these changes in the adult SD rat by altering hormonally-regulated estrous cyclicity. In Long-Evans...

  1. Comparison of gas chromatography/mass spectrometry and immunoassay techniques on concentrations of atrazine in storm runoff

    Science.gov (United States)

    Lydy, Michael J.; Carter, D.S.; Crawford, Charles G.

    1996-01-01

    Gas chromatography/mass spectrometry (GC/MS) and enzyme-linked immunosorbent assay (ELISA) techniques were used to measure concentrations of dissolved atrazine in 149 surface-water samples. Samples were collected during May 1992–September 1993 near the mouth of the White River (Indiana) and in two small tributaries of the river. GC/MS was performed on a Hewlett-Packard 5971 A, with electron impact ionization and selected ion monitoring of filtered water samples extracted by C-18 solid phase extraction; ELISA was performed with a magnetic-particle-based assay with photometric analysis. ELISA results compared reasonably well to GC/MS measurements at concentrations below the Maximum Contaminant Level for drinking water set by the U.S. Environmental Protection Agency (3.0 μg/L), but a systematic negative bias was observed at higher concentrations. When higher concentration samples were diluted into the linear range of calibration, the relation improved. A slight positive bias was seen in all of the ELISA data compared to the GC/MS results, and the bias could be partially explained by correcting the ELISA data for cross reactivity with other triazine herbicides. The highest concentrations of atrazine were found during the first major runoff event after the atrazine was applied. Concentrations decreased throughout the rest of the sampling period even though large runoff events occurred during this time, indicating that most atrazine loading to surface waters in the study area occurs within a few weeks after application.

  2. Exposure to atrazine affects the expression of key genes in metabolic pathways integral to energy homeostasis in Xenopus laevis tadpoles

    Energy Technology Data Exchange (ETDEWEB)

    Zaya, Renee M., E-mail: renee.zaya@wmich.edu [Great Lakes Environmental and Molecular Sciences Center, Department of Biological Sciences, 3425 Wood Hall, Western Michigan University, 1903 West Michigan Avenue, Kalamazoo, MI 49008 (United States); Amini, Zakariya, E-mail: zakariya.amini@wmich.edu [Great Lakes Environmental and Molecular Sciences Center, Department of Biological Sciences, 3425 Wood Hall, Western Michigan University, 1903 West Michigan Avenue, Kalamazoo, MI 49008 (United States); Whitaker, Ashley S., E-mail: ashley.s.whitaker@wmich.edu [Great Lakes Environmental and Molecular Sciences Center, Department of Biological Sciences, 3425 Wood Hall, Western Michigan University, 1903 West Michigan Avenue, Kalamazoo, MI 49008 (United States); Ide, Charles F., E-mail: charles.ide@wmich.edu [Great Lakes Environmental and Molecular Sciences Center, Department of Biological Sciences, 3425 Wood Hall, Western Michigan University, 1903 West Michigan Avenue, Kalamazoo, MI 49008 (United States)

    2011-08-15

    In our laboratory, Xenopus laevis tadpoles exposed throughout development to 200 or 400 {mu}g/L atrazine, concentrations reported to periodically occur in puddles, vernal ponds and runoff soon after application, were smaller and had smaller fat bodies (the tadpole's lipid storage organ) than controls. It was hypothesized that these changes were due to atrazine-related perturbations of energy homeostasis. To investigate this hypothesis, selected metabolic responses to exposure at the transcriptional and biochemical levels in atrazine-exposed tadpoles were measured. DNA microarray technology was used to determine which metabolic pathways were affected after developmental exposure to 400 {mu}g/L atrazine. From these data, genes representative of the affected pathways were selected for assay using quantitative real time polymerase chain reaction (qRT-PCR) to measure changes in expression during a 2-week exposure to 400 {mu}g/L. Finally, ATP levels were measured from tadpoles both early in and at termination of exposure to 200 and 400 {mu}g/L. Microarray analysis revealed significant differential gene expression in metabolic pathways involved with energy homeostasis. Pathways with increased transcription were associated with the conversion of lipids and proteins into energy. Pathways with decreased transcription were associated with carbohydrate metabolism, fat storage, and protein synthesis. Using qRT-PCR, changes in gene expression indicative of an early stress response to atrazine were noted. Exposed tadpoles had significant decreases in acyl-CoA dehydrogenase (AD) and glucocorticoid receptor protein (GR) mRNA after 24 h of exposure, and near-significant (p = 0.07) increases in peroxisome proliferator-activated receptor {beta} (PPAR-{beta}) mRNA by 72 h. Decreases in AD suggested decreases in fatty acid {beta}-oxidation while decreases in GR may have been a receptor desensitization response to a glucocorticoid surge. Involvement of PPAR-{beta}, an energy

  3. Implementation of a General Finite Element Code on an IBM PC Compatible Microcomputer.

    Science.gov (United States)

    1984-09-01

    l-r,0 ?CC.’j\\ WR1TE(#,’( APA )k’ PRICESSIN:G 9BLCY’ v, BLO-C 1,17 APPENDIX E MEF PROGRAM LISTINGS 4 The orogram listings for MEF are provided belowe...2,-30) (Vi :), ,!=-i, D- 2030 FORMATO )’ fl).iX,7E12.5) 40) CONTINUE C---- READ NODE CARDS 50 READ (MI, 1020) (’AV() 14=!,L16) 164 1020 tX FORM NEQ 00

  4. Joint source channel coding using arithmetic codes

    CERN Document Server

    Bi, Dongsheng

    2009-01-01

    Based on the encoding process, arithmetic codes can be viewed as tree codes and current proposals for decoding arithmetic codes with forbidden symbols belong to sequential decoding algorithms and their variants. In this monograph, we propose a new way of looking at arithmetic codes with forbidden symbols. If a limit is imposed on the maximum value of a key parameter in the encoder, this modified arithmetic encoder can also be modeled as a finite state machine and the code generated can be treated as a variable-length trellis code. The number of states used can be reduced and techniques used fo

  5. Attention selection, distractor suppression and N2pc.

    Science.gov (United States)

    Mazza, Veronica; Turatto, Massimo; Caramazza, Alfonso

    2009-01-01

    N2pc is generally interpreted as the electrocortical correlate of the distractor-suppression mechanisms through which attention selection takes place in humans. Here, we present data that challenge this common N2pc interpretation. In Experiment 1, multiple distractors induced greater N2pc amplitudes even when they facilitated target identification, despite the suppression account of the N2pc predicted the contrary; in Experiment 2, spatial proximity between target and distractors did not affect the N2pc amplitude, despite resulting in more interference in response times; in Experiment 3, heterogeneous distractors delayed response times but did not elicit a greater N2pc relative to homogeneous distractors again in contrast with what would have predicted the suppression hypothesis. These results do not support the notion that the N2pc unequivocally mirrors distractor-suppression processes. We propose that the N2pc indexes mechanisms involved in identifying and localizing relevant stimuli in the scene through enhancement of their features and not suppression of distractors.

  6. Chromosomal distribution of PcG proteins during Drosophila development.

    Directory of Open Access Journals (Sweden)

    Nicolas Nègre

    2006-06-01

    Full Text Available Polycomb group (PcG proteins are able to maintain the memory of silent transcriptional states of homeotic genes throughout development. In Drosophila, they form multimeric complexes that bind to specific DNA regulatory elements named PcG response elements (PREs. To date, few PREs have been identified and the chromosomal distribution of PcG proteins during development is unknown. We used chromatin immunoprecipitation (ChIP with genomic tiling path microarrays to analyze the binding profile of the PcG proteins Polycomb (PC and Polyhomeotic (PH across 10 Mb of euchromatin. We also analyzed the distribution of GAGA factor (GAF, a sequence-specific DNA binding protein that is found at most previously identified PREs. Our data show that PC and PH often bind to clustered regions within large loci that encode transcription factors which play multiple roles in developmental patterning and in the regulation of cell proliferation. GAF co-localizes with PC and PH to a limited extent, suggesting that GAF is not a necessary component of chromatin at PREs. Finally, the chromosome-association profile of PC and PH changes during development, suggesting that the function of these proteins in the regulation of some of their target genes might be more dynamic than previously anticipated.

  7. Hydrogen bonds in PC{sub 61}BM solids

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Chun-Qi [Department of Physics, Zhejiang University, Hangzhou 310027 (China); Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University, Hangzhou 311121 (China); Li, Wen-Jie; Du, Ying-Ying; Chen, Guang-Hua; Chen, Zheng; Li, Hai-Yang; Li, Hong-Nian, E-mail: phylihn@mail.zju.edu.cn [Department of Physics, Zhejiang University, Hangzhou 310027 (China)

    2015-09-15

    We have studied the hydrogen bonds in PC{sub 61}BM solids. Inter-molecular interaction is analyzed theoretically for the well-defined monoclinic (P2{sub 1}/n) structure. The results indicate that PC{sub 61}BM combines into C–H⋯O{sub d} bonded molecular chains, where O{sub d} denotes the doubly-bonded O atom of PC{sub 61}BM. The molecular chains are linked together by C–H⋯O{sub s} bonds, where O{sub s} denotes the singly-bonded O atom of PC{sub 61}BM. To reveal the consequences of hydrogen bond formation on the structural properties of PC{sub 61}BM solids (not limited to the monoclinic structure), we design and perform some experiments for annealed samples with the monoclinic (P2{sub 1}/n) PC{sub 61}BM as starting material. The experiments include differential scanning calorimetry, X-ray diffraction and infrared absorption measurements. Structural phase transitions are observed below the melting point. The C–H⋯O{sub d} bonds seem persisting in the altered structures. The inter-molecular hydrogen bonds can help to understand the phase separation in polymer/PC{sub 61}BM blends and may be responsible for the existence of liquid PC{sub 61}BM.

  8. Application of simplified PC-SAFT to glycol ethers

    DEFF Research Database (Denmark)

    Avlund, Ane Søgaard; Kontogeorgis, Georgios; Michelsen, Michael Locht

    2012-01-01

    The simplified PC-SAFT (sPC-SAFT) equation of state is applied for binary glycol ether-containing mixtures, and it is investigated how the results are influenced by inclusion of intramolecular association in the association theory. Three different glycol ethers are examined: 2-methoxyethanol, 2-e...

  9. Carbon and Nitrogen Isotope Analysis of Atrazine and Desethylatrazine at Sub-μg/L Concentrations in Groundwater

    Science.gov (United States)

    Schreglmann, Kathrin; Hoeche, Martina; Steinbeiss, Sibylle; Reinnicke, Sandra; Elsner, Martin

    2013-04-01

    Environmental degradation of organic micropollutants is difficult to monitor due to their diffuse and ubiquitous input. Current approaches - concentrations measurements over time, or daughter-to-parent compound ratios - may fall short, because they do not consider dilution, compound- specific sorption characteristics or alternative degradation pathways. Compound specific isotope analysis (CSIA) offers an alternative approach based on evidence from isotope values. Until now, however, the relatively high limits for precise isotope analysis by gas chromatography - isotope ratio mass spectrometry (GC-IRMS) have impeded CSIA of sub µg/L scale micropollutant concentrations in field samples. We present the first measurements of C and N isotope ratios of the herbicide atrazine and its metabolite desethylatrazine at concentrations of 100 to 1000 ng/L in natural groundwater samples. Solid phase extraction and preparative HPLC were tested and validated for preconcentration and cleanup of groundwater samples of up to 10 liters without bias by isotope effects. Matrix interferences after solid phase extraction could be greatly reduced by a preparative HPLC cleanup step prior to GC-IRMS analysis. Sensitivity was increased by a factor of 6 to 8 by changing the injection method from large-volume-injection to cold-on-column injection on the GC-IRMS system. Carbon and nitrogen isotope values of field samples showed no obvious correlation with concentrations or desethylatrazine-to-atrazine ratios. Contrary to expectations, however, δ13C values of desethylatrazine were consistently less negative than those of atrazine from the same sites. Potentially, this line of evidence may contain information about further desethylatrazine degradation. In such a case the common practice of using desethylatrazine-to-atrazine ratios would underestimate natural atrazine degradation.

  10. Roles of TaON and Ta(3)N(5) in the visible-Fenton-like degradation of atrazine.

    Science.gov (United States)

    Du, Yingxun; Zhao, Lu; Zhang, Yuanyuan

    2014-02-28

    In this study, the roles of TaON and Ta3N5 in the degradation of atrazine by the visible-Fenton-like system were examined in detail. The TaON and Ta3N5 samples prepared by the nitridation of Ta2O5 and characterized by XRD, DRS, BET and PL analyses. The results showed that the TaON sample had weaker absorption in the visible region but higher specific surface area than the Ta3N5 sample. The degradation rate of atrazine in visible-TaON-Fenton-like system was 2.64 times than that in visible-Ta3N5-Fenton-like system. Both Fe(2+) and H2O2 could be reduced by eCB (electrons in the conduction band) in TaON or Ta3N5, while atrazine could not be oxidized by hVB (holes in the valance band). OH is the active species for the degradation of atrazine in visible-TaON/Ta3N5-Fenton-like systems. Majority of OH originated from Fenton reaction. After Fe(3+) was reduced by eCB to Fe(2+), Fe(2+) reacted quickly with H2O2 to generate OH. In addition, by capturing eCB, a little of H2O2 was reduced to yield OH, which contributed a small fraction of atrazine degradation. Based on the experimental results, the roles of TaON and Ta3N5 in the visible-Fenton-like system were proposed. And the higher photocatalytic activity of TaON than Ta3N5 was suggested to be due to the higher separation efficiency of electrons and holes, which may be related to the larger specific surface area.

  11. Determination of atrazine and degradation products in Luxembourgish drinking water: origin and fate of potential endocrine-disrupting pesticides.

    Science.gov (United States)

    Bohn, T; Cocco, E; Gourdol, L; Guignard, C; Hoffmann, L

    2011-08-01

    Several pesticides have been hypothesized to act as endocrine-disrupting compounds, exhibiting hormonal activity and perturbing normal physiological functions. Among these, especially s-triazine herbicides have received increased attention. Despite being banned in many countries, including the European Union, atrazine is still the world's most widely used herbicide. Despite its discontinued use, considerable concentrations of atrazine and its degradation products, mainly desethylatrazine (DEA) and deisopropylatrazine (DIA), are still found in the environment, including drinking water sources. The aim of this investigation was to study concentrations of especially s-triazine herbicides and major degradation products in drinking water, including spring water, tap water and bottled water in Luxembourg. Spring water (2007/2008/2009, n = 69/69/69), tap water (2008/2009, n = 19/26), and bottled water (2007/2008/2009, n = 5/13/7) were sampled at locations in Luxembourg and investigated for pesticides by LC-ESI-MS/MS. Atrazine was the predominant triazine, detectable in many spring water locations, tap and bottled water, ranging (mean) from 0-57 (9), 0-44 (4), and 0-4 (1) ng l(-1), respectively. DEA and DIA in spring water ranged (mean) from 0-120 (19) and 0-27 (3) ng l(-1), with higher concentrations from agricultural areas and low molar ratios of DEA:atrazine high ratios of atrazine:nitrate suggesting point-source contamination. Levels (mean) of DEA and DIA in tap water were 0-62 (14) and 0-6 (water 0-11 (2) and 0-7 (2) ng l(-1). Simazine and other triazines were detected in traces (water, presumably partly due to non-agricultural contamination, with concentrations being below thresholds advocated by the European Union Directive 98/83/EC.

  12. A comparative study of the acute toxicity of the herbicide atrazine to cladocerans Daphnia magna, Ceriodaphnia silvestrii and Macrothrix flabelligera

    Directory of Open Access Journals (Sweden)

    Raquel Aparecida Moreira

    2014-03-01

    Full Text Available AIM: In this study we compared the sensitivity of three species of Cladocera, Daphnia magna, Ceriodaphnia silvestrii and Macrothrix flabelligera, to the commercial product of the herbicide Atrazine, the Atrazine Atanor 50 SC® (500 g/L, widely used on crops in Brazil. METHODS: Acute toxicity tests were performed at the nominal atrazine concentrations 2.25, 4.5, 9.0, 18.0, 36 and 72 mg L-1, on C. silvestrii and M. flabelligera and at 2.25, 4.5, 9.0, 18.0, 36, 72 and 144 mg L-1 on D. magna. The range of concentrations tested was established in a series of preliminary tests. RESULTS: The toxicity tests showed that the two species naturally occurring in water bodies in Brazil were more susceptible than Daphnia magna. The effective concentrations of Atrazine Atanor 50 SC® (EC50- 48 h to the species M. flabelligera, C. silvestrii and D. magna were 12.37 ± 2.67 mg L-1, 14.30 ± 1.55 mg L-1 and 50.41 ± 2.64 mg L-1, respectively. Furthermore, when EC50 observed here for M. flabelligera and C. silvestrii were compared with published values of EC50 or LC50 (mg L-1 for various aquatic organisms exposed to atrazine, it was seen that these two cladocerans were the most sensitive to the herbicide. CONCLUSIONS: Considering these results and the broad distribution of C. silvestrii and M. flabelligera in tropical and subtropical regions, it is concluded that these native species would be valuable test organisms in ecotoxicological tests, for the monitoring of toxic substances in tropical freshwaters.

  13. Online Instructional Design Approaches Utilizing a Tablet PC

    Directory of Open Access Journals (Sweden)

    Pam Lowry

    2009-11-01

    Full Text Available Online students can experience what instructional strategies can be utilized using a Tablet PC in online courses. This paper summarizes how inking in Word, Powerpoint, and Windows Journal can be effective in an online course both asynchronously and synchronously. Approaches concerning assignments, discussion boards, presentations, note taking are discussed and how they can be more effective for faculty members and students using a Tablet PC. Students actually experience how a Tablet PC can be utilized in an asynchronous and synchronous environment. In summary, preliminary data will be discussed from the students and professor’s point of view and next steps. As content and assignments are being designed and developed for an online graduate course, it is important to keep in mind teaching styles, student’s learning styles, and a faculty member’s approach to promoting a Tablet PC in an online course. Even though graduate students were not required to have a Tablet PC, the course enabled them to understand how effective a Tablet PC could be in an online course whether it was delivered asynchronous or synchronously. Powerpoint presentations were created to delivery asynchronously and synchronously content to students by utilizing a Tablet PC to illustrate concepts within the presentation. Assignments were created such as evaluating e-learning products, creating a Blackboard unit, evaluating online courses, group instruction sessions, and weekly discussion boards. As these assignments were graded, comments were written on their Word and Powerpoint files using Tablet PC inking. As the Tablet PC initiative is less than one year old at Lawrence Technological University, preliminary data is being collected from faculty members and students. After this class is taught summer 2008, additional research on the efforts of course design and student learning will be explored. The Tablet PC has the potential for enhancing online course delivery.

  14. Scanning tunneling microscopy investigation of self-assembled CuPc/F16CuPc binary superstructures on graphite.

    Science.gov (United States)

    Huang, Yu Li; Li, Hui; Ma, Jing; Huang, Han; Chen, Wei; Wee, Andrew T S

    2010-03-01

    The self-assembly of the binary molecular system comprising copper(II) phthalocyanine (CuPc) and copper-hexadecafluoro-phthalocyanine (F(16)CuPc) on graphite has been investigated by in situ low-temperature scanning tunneling microscopy (LT-STM). The adsorption of this binary molecular system on graphite results in the formation of a well-ordered chessboardlike nanopattern. The in-plane molecular orientation of the guest CuPc molecules can be tuned by varying the coverage. At low coverage, the sparse CuPc molecules are randomly embedded in the host F(16)CuPc monolayer, possessing two different in-plane orientations; as the CuPc coverage increases, the in-plane molecular orientations of CuPc and F(16)CuPc become unidirectional and a highly ordered chessboardlike pattern forms. Molecular dynamic (MD) simulation results suggest that the selective and directional intermolecular hydrogen bonding determines the in-plane molecular orientation as well as the supramolecular packing arrangement.

  15. Turbo Codes Extended with Outer BCH Code

    DEFF Research Database (Denmark)

    Andersen, Jakob Dahl

    1996-01-01

    The "error floor" observed in several simulations with the turbo codes is verified by calculation of an upper bound to the bit error rate for the ensemble of all interleavers. Also an easy way to calculate the weight enumerator used in this bound is presented. An extended coding scheme is proposed...... including an outer BCH code correcting a few bit errors....

  16. Detection and organization of atrazine-degrading genetic potential of seventeen bacterial isolates belonging to divergent taxa indicate a recent common origin of their catabolic functions

    DEFF Research Database (Denmark)

    El Azhari, Najoi

    2007-01-01

    A collection of 17 atrazine-degrading bacteria isolated from soils was studied to determine the composition of the atrazine-degrading genetic potential (i.e. trzN, trzD and atz) and the presence of IS1071. The characterization of seven new atrazine-degrading bacteria revealed for the first time...... the trzN-atzBC gene composition in Gram-negative bacteria such as Sinorhizobium sp. or Polaromonas sp. Three main atrazine-degrading gene combinations (i) trzN–atzBC, (ii) atzABC–trzD and (iii) atzABCDEF were observed. The atz and trz genes were often located on plasmids, suggesting that plasmid...

  17. A Discussion of Water Pollution in the United States and Mexico; with High School Laboratory Activities for Analysis of Lead, Atrazine, and Nitrate.

    Science.gov (United States)

    Kelter, Paul B.; Grundman, Julie; Hage, David S.; Carr, James D.; Castro-Acuna, Carlos Mauricio

    1997-01-01

    Presents discussions on sources, health impacts, methods of analysis as well as lengthy discussions of lead, nitrates, and atrazine as related to water pollution and the interdisciplinary nature of the modern chemistry curriculum. (DKM)

  18. Atrazine Does Not Induce Pica Behavior at Doses that Increase Hypothalamic-Pituitary-Adrenal Axis Activation and Cause Conditioned Taste Avoidance.

    Science.gov (United States)

    Previous work has shown that a single oral administration of atrazine (ATR), a chlorotriazine herbicide, induces dose-dependent increases in plasma adrenocorticotropic hormone (ACTH), serum corticosterone (CORT) and progesterone. The mechanism for these effects is unknown. To tes...

  19. Top Ten Inpatient Palliative Medicine Billing and Coding Mistakes (and How to Fix Them This Week)

    Science.gov (United States)

    Jones, Christopher A.; Bull, Janet; Acevedo, Jean

    2015-01-01

    Abstract Palliative care (PC) has undergone incredible growth in the last 10 years, having gained subspecialty status and penetration into 85% of hospitals over 300 beds. The comprehensive services provided by multiple members of the PC team combined with low reimbursement for nonprocedural medical care challenges all PC teams to operate with financial sustainability. Accurately and compliantly documenting and coding services provided to patients can help to maximize PC programs' revenues and limit operating subsidies received from health care systems or hospice programs. In this article we share common billing and coding mistakes made by our programs and colleagues while providing inpatient, consultative palliative care. Each mistake is explained and paired with a straightforward fix to enable compliant, efficient practice. This will allow clinicians to more accurately communicate to payers the complex care provided to inpatients by the PC team. This fuller picture of the complexity of care provided can increase reimbursements received by your PC program from payers. Understanding how to accurately document, code, and receive appropriate reimbursement will allow our field to continue to grow, broadening the reach of PC nationally to improve quality of life for all patients and families in need. PMID:25671789

  20. Transport of Alachlor, Atrazine, Dicamba, and Bromide through Silt and Loam Soils

    Science.gov (United States)

    Tindall, J. A.

    2015-12-01

    The herbicides alachlor, atrazine, and dicamba, as well as bromide were applied to soils overlying the High Plains aquifer in Nebraska, to both macropore and non-macropore sites. Three of 6 study areas (exhibiting a high percentage of macropores) were used for analysis of chemical transport. Twelve intact soil cores (30 cm diameter; 40 cm height), were excavated (two each from 0-40 cm and 40-80 cm depths). The first three study areas and soil cores were used to study preferential flow characteristics using dye staining and to determine hydraulic properties; the remaining cores were treated the same as field macropore sites. Two undisturbed experimental field plots, each with a 1 m2 surface area, were established in each of the three macropore study areas. Each preferential plot was instrumented with suction lysimeters, tensiometers, and neutron access tubes - 10 cm increments to 80 cm - and planted in corn. Three study areas that did not exhibit macropores had alachlor, atrazine, and dicamba and bromide disked into the top 15 cm of soil; concentrations were tracked for 120 days - samples were collected on a grid, distributed within 3 plots measuring 50 m x 50 m each. Core samples were collected prior to and immediately after application, and then at 30, 60, and 120 days after application. Each lab core sample was in 15-cm lengths from 0-15 cm, 15-30 cm, 45-60 cm, and 75-90 cm. For areas exhibiting macropores, herbicides had begun to move between 10-15 days after application with concentrations peaking at various depths after heavy rainfall events. Field lysimeter samples showed increases in concentrations of herbicides at depths where laboratory data indicated greater percentages of preferential flowpaths. Concentrations of atrazine, alachlor and dicamba exceeding 0.30, 0.30, and 0.05 μg m1-1 respectively were observed with depth (10-30 cm and 50-70 cm) after two months following heavy rainfall events indicating that preferential flowpaths were a significant

  1. Spatial and temporal variation of algal assemblages in six Midwest agricultural streams having varying levels of atrazine and other physicochemical attributes

    Energy Technology Data Exchange (ETDEWEB)

    Andrus, J. Malia, E-mail: andrusm@waterborne-env.com [Waterborne Environmental, Inc., 2001 South First Street, Suite 109, Champaign, IL 61820 (United States); Winter, Diane, E-mail: dwinter1@juno.com [Rhithron Associates, Inc., 33 Fort Missoula Rd., Missoula, MT 59804 (United States); Algal Analysis, LLC, Missoula, MT (United States); Scanlan, Michael, E-mail: mscanlan@maptech-inc.com [MapTech, Inc., 3154 State Street, Blacksburg, VA 24060 (United States); Sullivan, Sean, E-mail: ssullivan@rhithron.com [Rhithron Associates, Inc., 33 Fort Missoula Rd., Missoula, MT 59804 (United States); Bollman, Wease, E-mail: wbollman@rhithron.com [Rhithron Associates, Inc., 33 Fort Missoula Rd., Missoula, MT 59804 (United States); Waggoner, J.B., E-mail: jwaggoner@inovatia.com [Inovatia, Inc., 120 East Davis Street, Fayette, MO 65248 (United States); Hosmer, Alan J., E-mail: alan.hosmer@syngenta.com [Syngenta Crop Protection, LLC, 410 Swing Rd., Greensboro, NC 27419 (United States); Brain, Richard A., E-mail: richard.brain@syngenta.com [Syngenta Crop Protection, LLC, 410 Swing Rd., Greensboro, NC 27419 (United States)

    2015-02-01

    Potential effects of pesticides on stream algae occur alongside complex environmental influences; in situ studies examining these effects together are few, and have not typically controlled for collinearity of variables. We monitored the dynamics of periphyton, phytoplankton, and environmental factors including atrazine, and other water chemistry variables at 6 agricultural streams in the Midwest US from spring to summer of 2011 and 2012, and used variation partitioning of community models to determine the community inertia that is explained uniquely and/or jointly by atrazine and other environmental factors or groups of factors. Periphyton and phytoplankton assemblages were significantly structured by year, day of year, and site, and exhibited dynamic synchrony both between site–years and between periphyton and phytoplankton in the same site–year. The majority of inertia in the models (55.4% for periphyton, 68.4% for phytoplankton) was unexplained. The explained inertia in the models was predominantly shared (confounded) between variables and variable groups (13.3, 30.9%); the magnitude of inertia that was explained uniquely by variable groups (15.1, 18.3%) was of the order hydroclimate > chemistry > geography > atrazine for periphyton, and chemistry > hydroclimate > geography > atrazine for phytoplankton. The variables most influential to the assemblage structure included flow and velocity variables, and time since pulses above certain thresholds of nitrate + nitrite, total phosphorus, total suspended solids, and atrazine. Time since a ≥ 30 μg/L atrazine pulse uniquely explained more inertia than time since pulses ≥ 10 μg/L or daily or historic atrazine concentrations; this result is consistent with studies concluding that the effects of atrazine on algae typically only occur at ≥ 30 μg/L and are recovered from. - Highlights: • We monitored algal communities at 6 Midwest streams receiving atrazine in 2011 and 2012. • Partitioning of CCA models of

  2. PC/ASA合金的研发%Research on PC/ASA Alloy Performance and Preparation Process

    Institute of Scientific and Technical Information of China (English)

    黄李胜; 李景; 麦伟宗; 赖世亮

    2016-01-01

    利用双螺杆挤出机制备PC/ASA合金,探讨了不同PC与ASA配比对性能的影响。结果表明:在PC/ASA体系中,PC与ASA的配比为70∶30,添加4%的相容剂SMA以及0.8%的抗氧剂、润滑剂,能获得最优的性能:悬臂梁缺口冲击强度达66.7kJ/m2,拉伸强度达56.1MPa,弯曲强度达82.3MPa,热变形温度达105.6℃;同时比同等条件下制备出来的PC/ABS合金拥有更好的耐光性。%Using a twin-screw extruder equipment,PC/ASA alloy was prepared,the effects of different ratio of PC and ASA on performance were investigated. The results showed that:in PC/ASA system,PC and ASA ratio is 70∶30,adding compatibility agent SMA 4% and 0. 8% of antioxidant and lubricant,can achieve optimal perform-ance:Izod notched impact strength of 66. 7kJ/m2 , the tensile strength of 56. 1MPa, the bending strength of 82. 3MPa,heat distortion temperature of 105. 6℃;while PC/ABS was prepared under the same conditions,PC/ASA alloy has better lightfastness than PC/ABS.

  3. Phenomenology of $P_c(4380)^+$, $P_c(4450)^+$ and related states

    CERN Document Server

    Burns, T J

    2015-01-01

    The $P_c(4380)^+$ and $P_c(4450)^+$ states recently discovered at LHCb have masses close to several relevant thresholds, which suggests they can be described in terms of meson-baryon degrees of freedom. This article explores the phenomenology of these states, and their possible partners, from this point of view. Competing models can be distinguished by the masses of the neutral partners which have yet to be observed, and the existence or otherwise of further partners with different isospin, spin, and parity. Future experimental studies in different decay channels can also discriminate among models, using selection rules and algebraic relations among decays. Among the several possible meson-baryon pairs which could be important, one implies that the states are mixtures of isospins 1/2 and 3/2, with characteristic signatures in production and decay. A previous experimental study of a Cabibbo-suppressed decay showed no evidence for the states, and further analysis is required to establish the significance of thi...

  4. Toxicity Assessment of Atrazine and Related Triazine Compounds in the Microtox Assay, and Computational Modeling for Their Structure-Activity Relationship

    Directory of Open Access Journals (Sweden)

    Jerzy Leszczynski

    2000-10-01

    Full Text Available The triazines are a group of chemically similar herbicides including atrazine, cyanazine, and propazine, primarily used to control broadleaf weeds. About 64 to 80 million lbs of atrazine alone are used each year in the United States, making it one of the two most widely used pesticides in the country. All triazines are somewhat persistent in water and mobile in soil. They are among the most frequently detected pesticides in groundwater. They are considered as possible human carcinogens (Group C based on an increase in mammary gland tumors in female laboratory animals. In this research, we performed the Microtox Assay to investigate the acute toxicity of a significant number of triazines including atrazine, atraton, ametryne, bladex, prometryne, and propazine, and some of their degradation products including atrazine desethyl, atrazine deisopropyl, and didealkyled triazine. Tests were carried out as described by Azur Environmental [1]. The procedure measured the relative acute toxicity of triazines, producing data for the calculation of triazine concentrations effecting 50% reduction in bioluminescence (EC50s. Quantitative structure-activity relationships (QSAR were examined based on the molecular properties obtained from quantum mechanical predictions performed for each compound. Toxicity tests yielded EC50 values of 39.87, 273.20, 226.80, 36.96, 81.86, 82.68, 12.74, 11.80, and 78.50 mg/L for atrazine, propazine, prometryne, atraton, atrazine desethyl, atrazine deisopropyl, didealkylated triazine, ametryne, and bladex, respectively; indicating that ametryne was the most toxic chemical while propazine was the least toxic. QSAR evaluation resulted in a coefficient of determination (r2 of 0.86, indicating a good value of toxicity prediction based on the chemical structures/properties of tested triazines.

  5. Conserved Molecular and Epigenetic Determinants of Aromatase Gene Induction by the Herbicide Atrazine in Human and Rat Cellular Models Relevant to Breast Cancer Risk

    OpenAIRE

    2011-01-01

    AbstractConserved Molecular and Epigenetic Determinants of Aromatase Gene Induction by the Herbicide Atrazine in Human and Rat Cellular Models Relevant to Breast Cancer Risk ByTheresa Ryan StueveDoctor of Philosophy in Molecular ToxicologyUniversity of California, BerkeleyProfessor Gary Firestone, Co-ChairProfessor Dale Leitman, Co-ChairFall 2011The widely-applied herbicide atrazine (ATR) is a potent endocrine disruptor that elicits anti-androgenic and estrogenic effects, often at concentrat...

  6. Rateless feedback codes

    DEFF Research Database (Denmark)

    Sørensen, Jesper Hemming; Koike-Akino, Toshiaki; Orlik, Philip

    2012-01-01

    This paper proposes a concept called rateless feedback coding. We redesign the existing LT and Raptor codes, by introducing new degree distributions for the case when a few feedback opportunities are available. We show that incorporating feedback to LT codes can significantly decrease both...... the coding overhead and the encoding/decoding complexity. Moreover, we show that, at the price of a slight increase in the coding overhead, linear complexity is achieved with Raptor feedback coding....

  7. Concentrations and transport of atrazine in the Delaware River-Perry Lake system, northeast Kansas, July 1993 through September 1995

    Science.gov (United States)

    Pope, L.M.; Brewer, L.D.; Foley, G.A.; Morgan, S.C.

    1996-01-01

    A study of the distribution and transport of atrazine in surface water in the 1,117 square-mile Delaware River Basin in northeast Kansas was conducted from July 1992 through September 1995. The purpose of this report is to present information to assess the present (1992-95) conditions and possible future changes in the distribution and magnitude of atrazine concentrations, loads, and yields spatially, temporally, and in relation to hydrologic conditions and land-use characteristics. A network of 11 stream-monitoring and sample-collection sites was established within the basin. Stream- water samples were collected during a wide range of hydrologic conditions throughout the study. Nearly 5,000 samples were analyzed by enzyme- linked immunosorbent assay (ELISA) for triazine herbicide concentrations. Daily mean triazine herbicide concentrations were calculated for all sampling sites and subsequently used to estimate daily mean atrazine concentrations with a linear- regression relation between ELISA-derived triazine concentrations and atrazine concentrations determined by gas chromatography/mass spectrometry for 141 dual-analyzed surface-water samples. During May, June, and July, time-weighted, daily mean atrazine concentrations in streams in the Delaware River Basin commonly exceeded the value of 3.0-ug/L (micrograms per liter) annual mean Maximum Contaminant Level (MCL) established by the U.S. Environmental Protection Agency for drinking-water supplies. Time-weighted, daily mean concentrations equal to or greater than 20 ug/L were not uncommon. However, most time- weighted, daily mean concentrations were less than 1.0 ug/L from August through April. The largest time-weighted, monthly mean atrazine concentrations occurred during May, June, and July. Most monthly mean concentrations between August and April were less than 0.50 ug/L. Large differences were documented in monthly mean concentrations within the basin. Sites receiving runoff from the northern and

  8. Coding for dummies

    CERN Document Server

    Abraham, Nikhil

    2015-01-01

    Hands-on exercises help you learn to code like a pro No coding experience is required for Coding For Dummies,your one-stop guide to building a foundation of knowledge inwriting computer code for web, application, and softwaredevelopment. It doesn't matter if you've dabbled in coding or neverwritten a line of code, this book guides you through the basics.Using foundational web development languages like HTML, CSS, andJavaScript, it explains in plain English how coding works and whyit's needed. Online exercises developed by Codecademy, a leading online codetraining site, help hone coding skill

  9. Advanced video coding systems

    CERN Document Server

    Gao, Wen

    2015-01-01

    This comprehensive and accessible text/reference presents an overview of the state of the art in video coding technology. Specifically, the book introduces the tools of the AVS2 standard, describing how AVS2 can help to achieve a significant improvement in coding efficiency for future video networks and applications by incorporating smarter coding tools such as scene video coding. Topics and features: introduces the basic concepts in video coding, and presents a short history of video coding technology and standards; reviews the coding framework, main coding tools, and syntax structure of AV

  10. Atrazine dissipation and its impact on the microbial communities and community level physiological profiles in a microcosm simulating the biomixture of on-farm biopurification system.

    Science.gov (United States)

    Tortella, G R; Mella-Herrera, R A; Sousa, D Z; Rubilar, O; Acuña, J J; Briceño, G; Diez, M C

    2013-09-15

    The effects of repeated atrazine application (40 mg a.i.kg(-1)) on its degradation, microbial communities and enzyme activities were studied in a peat based biomixture composed by straw, soil and peat in the volumetric proportions of 2:1:1 that can be used in on-farm biopurification system. Atrazine removal efficiency was high (96%, 78% and 96%) after each atrazine application and did not show a lag phase. Microbial enzyme activities were reduced significantly with atrazine application but rapidly recovered. Microbial diversity obtained by BiologEcoplate was similar after the first and second atrazine application. However, an inhibitory effect was observed after the third application. After each atrazine application, culturable fungi were reduced, but rapidly recovered without significant changes in culturable bacteria and actinomycetes compared to the control. Denaturing gradient gel electrophoresis (DGGE) patterns demonstrated that microbial community structure remained relatively stable in time when compared to the controls. In conclusion, our results demonstrated that after successive ATZ applications, the peat based biomixture had a good degradation capacity. Moreover, microbiological assays demonstrated the robustness of the peat based biomixture from a microbiological point of view to support pesticide degradation.

  11. Analysing the fate of nanopesticides in soil and the applicability of regulatory protocols using a polymer-based nanoformulation of atrazine.

    Science.gov (United States)

    Kah, Melanie; Machinski, Patrick; Koerner, Petra; Tiede, Karen; Grillo, Renato; Fraceto, Leonardo Fernandes; Hofmann, Thilo

    2014-10-01

    For the first time, regulatory protocols defined in the OECD guidelines were applied to determine the fate properties of a nanopesticide in two agricultural soils with contrasting characteristics. The nanoformulation studied had no effect on the degradation kinetics of atrazine indicating that (1) the release of atrazine from the polymer nanocarriers occurred rapidly relative to the degradation kinetics (half-lives 36-53 days) and/or that (2) atrazine associated with the nanocarriers was subject to biotic or abiotic degradation. Sorption coefficients, derived from a batch and a centrifugation technique at a realistic soil-to-solution ratio, were higher for the nanoformulated atrazine than for the pure active ingredient. Results indicate that the nanoformulation had an effect on the fate of atrazine. However, since the protocols applied were designed to assess solutes, conclusions about the transport of atrazine loaded onto the nanocarriers should be made extremely cautiously. The centrifugation method applied over time (here over 7 days) appears to be a useful tool to indirectly assess the durability of nanopesticides under realistic soil-to-solution ratios and estimate the period of time during which an influence on the fate of the active ingredient may be expected. More detailed investigations into the bioavailability and durability of nanopesticides are necessary and will require the development of novel methods suitable to address both the "nano" and "organic" characteristics of polymer-based nanopesticides.

  12. Effect of atrazine and fenitrothion at no-observed-effect-levels (NOEL) on amphibian and mammalian corticosterone-binding-globulin (CBG).

    Science.gov (United States)

    Hernández, Sandra E; Sernia, Conrad; Bradley, Adrian J

    2014-11-01

    This study determines the effect of atrazine and fenitrothion no-observed-effect-levels (NOEL) on the binding of corticosterone (B) to corticosterone-binding-globulin (CBG) in an amphibian and a mammal. Plasma from five cane toads and five Wistar rats was exposed to atrazine and fenitrothion at the NOEL approved for Australian fresh water residues and by the World Health Organization (WHO). The concentration required to displace 50% (IC50) of B binding to CBG was determined by a competitive microdialysis protein assay. Competition studies showed that both atrazine and fenitrothion at NOEL are able to compete with B for CBG binding sites in toad and rat plasma. The IC50 levels for atrazine in toads and rats were 0.004 nmol/l and 0.09 nmol/l respectively. In the case of fenitrothion the IC50 level found in toads was 0.007 nmol/l, and 0.025 nmol/l in rats. Plasma dilution curves showed parallelism with the curve of B, demonstrating that these agro-chemicals are competitively inhibiting binding to CBG. The displacement of B by atrazine and fenitrothion would affect the total:free ratio of B and consequently disrupt the normal stress response. This is the first time that the potential disruptive effect of atrazine and fenitrothion on B-CBG interaction at the NOELs has been demonstrated in amphibian and mammalian models.

  13. The Australian experience with the PC-EVN recorder

    CERN Document Server

    Dodson, R; West, C; Phillips, C; Tzioumis, A K; Ritakari, J; Briggs, F

    2004-01-01

    We report on our experiences using the Metsahovi Radio Observatory's (MRO) VLBI Standard Interface (VSI, Whitney 2002) recorder in a number of astronomical applications. The PC-EVN device is a direct memory access (DMA) interface which allows 512 megabit per second (Mbps) or better recording to "off the shelf" PC components. We have used this setup to record at 640 Mbps for a pulsar coherent dispersion system and at 256 Mpbs for a global VLBI session. We have also demonstrated recording at 512 Mbps and will shortly form cross correlations between the CPSR-II and the PC-EVN systems.

  14. Transformation of the Herbicides MCPP and Atrazine under Natural Aquifer Conditions

    DEFF Research Database (Denmark)

    Agertved, Jeanette; Ruegge, Kirsten; Barker, James

    1992-01-01

    The potential for aerobic biotransformation of the herbicides MCPP[(+/-)-2-(4-chloro-2-methylphenoxy)propionic acid] and Atrazine [2-chloro-4-ethylamino-6-isopropylamino-s-triazine] under natural aquifer conditions was investigated. A natural gradient experiment was carried out in an aerobic ground-water...... zone at the Canadian Forces Base Borden, Borden, Ontario, Canada. Over 90 days, a continuous plume was created by weekly injections of the herbicides (average concentrations of 400 μg/1 each), together with a conservative tracer, chloride. The fate of the herbicides was monitored at multilevel...... piezometers located downgradient from the injection well. In parallel, experiments with in situ testers (Gillham et al., 1990) were set up in the aquifer and microcosms were set up in the laboratory. For MCPP, the natural gradient experiment showed an adaptation period of 42-56 days followed by transformation...

  15. Degradation of the Pesticides Mecoprop and Atrazine in Unpolluted Sandy Aquifers

    DEFF Research Database (Denmark)

    Klint, Mikala; Arvin, Erik; Jensen, Bjørn K.

    1993-01-01

    The potential for biodegradation of the pesticides mecoprop ((+/-)-2-(4-chloro-2-methyl-phenoxy)propionic acid) and atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) in an aerobic aquifer was investigated in laboratory batch experiments. The experiments were performed with groundwater...... and suspensions of groundwater and aquifer sediment collected from a pristine sandy aquifer. Following a lag period of 35 to 40 d, mecoprop in a concentration of 100 mu-g/L was degraded in 30 d in groundwater at 10 degree C. New additions of 100 to 140 mu-g mecoprop/L were degraded within a week. In suspensions...... of groundwater and aquifer sediment, mecoprop in the concentration range 75 to 300 mu-g/L was degraded in 15 d, following a lag period of less than 7 d. Experiments performed with sediments taken from different depths indicate that there was a considerable variation in the degradation potential within...

  16. Potential for isoproturon, atrazine and mecoprop to be degraded within a chalk aquifer system

    Science.gov (United States)

    Johnson, Andrew C.; White, Craig; Lal Bhardwaj, C.

    2000-06-01

    The potential for herbicide degradation in an unconfined chalk aquifer was examined by collecting and spiking fresh samples and incubating them in the laboratory. The microcosms were incubated at 20°C under aerobic conditions and spiked with either isoproturon, atrazine or mecoprop at a concentration of 100 μg/l. The samples were obtained from a single fieldsite within the Upper Chalk aquifer in Hampshire, UK. Groundwater samples required the presence of sterile chalk in a ratio of at least 1:13 to promote isoproturon degradation. An isoproturon degradation potential existed in the soil, and the chalk unsaturated and saturated zones. However, no degradation of isoproturon in the unsaturated zone was observed when a more appropriate simulation of in-situ moisture conditions was carried out. Apart from the soil, no potential for atrazine or mecoprop degradation could be detected in the same samples over a 200-day incubation. In a series of groundwater samples taken from different boreholes, 10-300 m apart, large differences in isoproturon degradation potential were observed. Removal rates for 100 μg/l isoproturon varied from 83-425 ng/day, but in some samples no degradation potential could be detected. The primary metabolite which could be distinguished from isoproturon degradation in chalk and groundwater was monodesmethyl-isoproturon. When a chalk groundwater sample was spiked with isoproturon at 0.9 μg/l, this was not degraded over a 300-day incubation period. Further experiments with fresh groundwater from a Triassic Sandstone site illustrated that groundwater bacteria could degrade isoproturon at the more realistic temperature of 10°C as well as at 20°C.

  17. Raman and SERS study on atrazine, prometryn and simetryn triazine herbicides

    Science.gov (United States)

    Bonora, Sergio; Benassi, Enrico; Maris, Assimo; Tugnoli, Vitaliano; Ottani, Stefano; Di Foggia, Michele

    2013-05-01

    In the present study, we considered the Raman spectra of atrazine, prometryn and simetryn, in the solid form and in polar and apolar solvents, extending the investigation in the very diluted aqueous solutions (ppm) range by using the SERS technique. We performed theoretical calculations at the B3LYP/aug-cc-pVQZ level on the three triazines, alone and in solution with polar and apolar solvents. An excellent agreement between theoretical and experimental frequencies was reached, with differences lying within few wavenumbers. The small differences observed can be ascribed to the solid crystalline phase and can be caused by local deviations in the uniformity of the crystalline field or to a coupling with lattice vibrations. Also the theoretical and experimental peak intensities well agreed and in most cases lied within ±10%, the differences being ascribed to the local non-homogeneity of dielectric properties in the crystal. Moreover, this behavior confirmed the rigidity of the molecules and that their structure was not involved during the solution process. The theoretical SERS spectra at B3LYP/6-311+G(d,p) level of triazines bound to an Ag2 metal cluster offered an acceptable qualitative agreement with the experimental ones, suggesting that the stronger interaction site of triazines with Ag2 was on the less sterical hindered aromatic nitrogen atom, namely forming the N6⋯Ag2 molecular complex with atrazine, and the N2⋯Ag2 or N4⋯Ag2 molecular complexes with simetryn and prometryn. The agreement between calculated and experimental SERS spectra was not as good as that observed for the Raman spectra of pure compounds, but the trend of the theoretical spectra offered a useful guideline for the comprehension of the interaction sites and of the structural modification after adsorption on silver particles.

  18. Changes in cellular energy allocation in Enchytraeus albidus when exposed to dimethoate, atrazine, and carbendazim.

    Science.gov (United States)

    Novais, Sara C; Amorim, Mónica J B

    2013-12-01

    Cellular energy allocation (CEA) is a methodology developed to evaluate the effects of toxic stress on the metabolic balance of organisms. It consists of the integration of the energy reserves available (Ea; total carbohydrate, protein and lipid content) and energy consumption (Ec) estimated by measuring electron transport system (ETS) activity. The main goal of the present study was to evaluate the effects on the energy budget of the soil invertebrate Enchytraeus albidus (Oligochaeta) after exposure to dimethoate, atrazine, and carbendazim (by testing the reproduction 10% effective concentration, 20% effective concentration, 50% effective concentration and 90% effective concentration) over periods of time from 0 d to 2 d, 4 d, and 8 d. Significant changes in energy reserves were observed with all pesticides, together with effects on energy consumption. Carbohydrates were the first energy source to be used, and clear depletions occurred with all pesticides. Energy consumption increased generally over longer exposures and with higher concentrations of the pesticides. Although clear changes were seen in the individual energy reserve budgets and on Ec, CEA was only significantly reduced with atrazine exposures longer than 4 d. The nearly absent effects on CEA at concentrations known to affect reproduction indicate that the reduction in reproduction is not likely to be caused by a reduction in the total energy budget during the first 8 d of exposure. The present study showed the importance of complementing CEA interpretation with the individual Ea and Ec parameters, in particular if these show opposite balances. The Ea and Ec results were in good agreement with gene transcription results from a parallel study, hence suggesting translation and showing the advantage of combining various effect levels to advance the understanding of mechanisms.

  19. Effect of fly ash amendment on metolachlor and atrazine degradation and microbial activity in two soils.

    Science.gov (United States)

    Ghosh, Rakesh Kumar; Singh, Neera; Singh, Shashi Bala

    2016-08-01

    The study reports the effect of Inderprastha (IP) and Badarpur (BP) fly ashes on degradation of metolachlor and atrazine in Inceptisol and Alfisol soils. Metolachlor dissipated at faster rate in Alfisol (t1/2 8.2-8.6 days) than in Inceptisol (t1/2 13.2-14.3 days). The fly ashes enhanced the persistence of metolachlor in both the soils; however, the extent of effect was more in Inceptisol (t1/2 16.6-33.8 days) than Alfisol (t1/2 8.4-12 days) and effect increased with fly ash dose. 2-Ethyl-6-methylacetanilide was detected as the only metabolite of metolachlor. Atrazine was more persistent in flooded soils (t1/2 10.8-20.3 days) than nonflooded soils (t1/2 3.7-12.6 days) and fly ash increased its persistence, but effect was more pronounced in the flooded Inceptisol (t1/2 23.7-31 days) and nonflooded Alfisol (t1/2 6.3-10.1 days). Increased herbicide sorption in the fly ash-amended soils might have contributed to the increased pesticide persistence. The IP fly ash inhibited microbial biomass carbon at 5 % amendment levels in both the soils, while BP fly ash slightly increased microbial biomass carbon (MBC) content. Dehydrogenase activity was inhibited by both fly ashes in both the soils with maximum inhibition observed in the IP fly ash-amended Alfisol. No significant effect of fly ash amendment was observed on the fluorescein diacetate activity.

  20. [Study on fluorescence labeling and determination of polypeptide (PC2~PC6) by high performance liquid chromatography].

    Science.gov (United States)

    Li, Jing-xi; Gao, Li-jie; Cao, Wei; Zheng, Li; Chen, Jun-hui; Xu, Xiu-li; Wang, Xiao-ru

    2014-12-01

    This study was based on the thiol groups (-SH) of PC2~PC6, which could be reacted with the Monobromobimane (mBBr), in order to get polypeptide derivatives with fluorescent signal. A new method was developed for measuring the Polypeptides by high performance liquid chromatography with fluorescence detector, then the chromatographic conditions of HPLC was optimized; meawhile the reaction proportion of PCs and mBBr was identified by Trap-MS. The results showed that, the reaction proportion of PCs and mBBr was 1:1, the polypeptide derivatives had good stability; the five compounds separation was better, and the peak time focused on the 16.6~22.0 min; the linear correlation coefficient of PC2, PC3, PC4, PC5 and PC6 was >0.9991, and the limits of quantification were 0.3, 0.05, 0.3, 0.5 and 0.8 mg · L(-1) respectively, the recovery rate was 83.0%-102.0%; the method was reproducible, RSD<2%, this method for measuring the peptide compounds was rapid and accurate.

  1. Guest Foreword by Lord Phillips KG PC

    Directory of Open Access Journals (Sweden)

    Nicholas A. Phillips

    2012-04-01

    Full Text Available The Rt Hon The Lord Phillips of Worth Matravers KG PC, President of the Supreme Court of the United Kingdom of Great Britain and Northern Ireland Ambition and excellence. Those two words epitomize Qatar. Under the leadership of his Highness the Emir, this small State has set out to make an impact on the world that belies its size. Ambitious was the plan to have an international broadcasting station. Ambitious was the plan to build from scratch a Museum of Islamic Art. Ambitious was the bid – the successful bid to host the World Cup in 2022. Ambitious is the bid to stage the Olympic Games in 2020. Qatar not merely has ambitions, it realizes its ambitions. And when it does so it is not enough to say that the result is ‘world class’, for Qatar sets out to be a world leader in whatever it puts its hand to. Excellence is the norm. Al Jazeera has established itself as the broadcasting station of choice for many throughout the world. The Doha Museum of Islamic Art is recognized as being second to none. In addition, the scale and standard of development in Doha itself is setting new standards of excellence in the fields of architecture and civil engineering. Thus when Qatar focuses its energies on education and the law, high achievements are expected. I shall have the honour of helping to achieve those expectations when I succeed Lord Woolf as President of Qatar’s new and impressive Civil and Commercial Court. The College of Law at Qatar University is already achieving excellence in the field of legal education. So, naturally, all expect great things of this new International Review of Law and I am delighted to have been invited to welcome it by this foreword. The range of the first edition is both international and topical. Those countries that have experienced the turbulence of the Arab Spring are settling new constitutions, and other countries are bent on constitutional reform designed to avoid such turbulence. So an erudite article on

  2. Integral Study of Atrazine Behaviour in Field Lysimeters in Argentinean Humid Pampas Soils Estudio Integral del Comportamiento de Atrazina en Lisímetros de Campo en Suelos de la Pampa Húmeda Argentina

    OpenAIRE

    Susana Hang; Adrián Andriulo; Carolina Sasal; Mirtha M Nassetta; Silvina Portela; Ana I Cañas

    2010-01-01

    Atrazine behavior during crop maize (Zea mays L.) production in soils of Argentine humid pampas was investigated. Lysimeters (3.3 x 3.3 x 1.4 m) with a Typic Argiudoll (Pergamino) and others with a Typic Hapludoll (Junín) were monitored for drainage water content and atrazine concentrations in soil and water. Soil profiles were sampled in four depths in three dates, and water drainage pooled in four periods. Most of atrazine loss in drainage occurred within 30 d of atrazine application being ...

  3. Application of sPC-SAFT and group contribution sPC-SAFT to polymer systems-Capabilities and limitations

    DEFF Research Database (Denmark)

    Tihic, Amra; von Solms, Nicolas; Michelsen, Michael Locht

    2009-01-01

    A group contribution (GC) version of the simplified Perturbed-Chain Statistical Associating Fluid Theory (sPC-SAFT) Equation of State is proposed in a previous work [A. Tihic, G.M. Kontogeorgis, N. von Solms, M.L. Michelsen, L Constantinou, Ind. Eng. Chem. Res. 47 (2008) 5092-5101]. The reported......PC-SAFT model, with and without GC. The reported results contribute to a better understanding of the applicability of the sPC-SAFT model to binary polymer mixtures, and identify both models as good predictive tools for several industrial applications. Limitations are also identified and discussed....

  4. NEW CONCEPT FOR DETERMINING THE ORDERS OF SAC AND PC

    Institute of Scientific and Technical Information of China (English)

    Wei Baodian; Liu Dongsu; Ma Wenping; Wang Xinmei

    2004-01-01

    The autocorrelation of a Boolean function possesses the capability to reflect such characteristics as linear structure, Strict Avalanche Criterion(SAC) and Propagation Criterion(PC)of degree k. But it can do nothing in determining the order of SAC or PC. A calculating table for the autocorrelation is constructed in this paper so as to show what is beyond the autocorrelation and how the three cryptographic characteristics are exhibited. A deeper study on the calculating table in a similar way has helped us to develop a new concept, named as the general autocorrelation, to address efficiently the problem how to determine the orders of SAC and PC. The application on the Advanced Encryption Standard(AES) shows the SAC and PC characteristics of Boolean functions of AES S-box.

  5. 2010 ME70 Workshop (PC1003, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The third leg of the 2010 SEAMAP Reeffish Survey, PC 1003, was originally scheduled as an experimental multibeam sonar workshop. However, on July 12, 2010, FSV...

  6. Synthesis and Characterization of Compatibilizer TLCP-b-PC

    Institute of Scientific and Technical Information of China (English)

    XIAO Ru; JIN Shu-wen; ZHANG Yue-ting; WU Cheng-xun

    2002-01-01

    The compatibilizer (TLCP-b-PC) of 60PHB/PET thermotropic liquid crystal polymer (TLCP) and polycarbonate (PC) blend system was prepared. The synthesis and characterization of the compatibilizer as well as its effects on the microscopic morphology and the mechanical properties of the TLCP/PC blend system were studied with a series of analysis ways, such as Soxhlet extraction, infrared absorption spectroscopy,electron microscopy, etc. It is shown that the ideal reaction condition for preparing the compatibilizer is:the reaction temperature of 275℃, the reaction time of 20minutes and without catalyst. And the compatibilizer can improve the compatibility of the blending system of 60PHB/PET and PC.

  7. Application of PC-SAFT to glycol containing systems - PC-SAFT towards a predictive approach

    DEFF Research Database (Denmark)

    Grenner, Andreas; Kontogeorgis, Georgios; von Solms, Nicolas;

    2007-01-01

    For equations of state of the SAFT type a major limitation is the procedure of obtaining pure compound parameters using saturated vapor pressure and liquid density data. However, for complex compounds such data are often not available. One solution is to develop a group contribution scheme...... for estimating pure compound parameters from low molecular weight data and extrapolate to complex compounds. For associating compounds this is not trivial since the two parameters for association (association energy and association volume) need to be fixed for a group. In this work, which focuses on glycols, new...... general pure compound parameters were obtained for PC-SAFT which are able to perform well for both vapor-liquid equilibria (VLE) and liquid-liquid equilibria (LLE). Linear trends of non-association parameters were obtained with respect to the molar mass. However, identical values for the association...

  8. Locally Orderless Registration Code

    DEFF Research Database (Denmark)

    2012-01-01

    This is code for the TPAMI paper "Locally Orderless Registration". The code requires intel threadding building blocks installed and is provided for 64 bit on mac, linux and windows.......This is code for the TPAMI paper "Locally Orderless Registration". The code requires intel threadding building blocks installed and is provided for 64 bit on mac, linux and windows....

  9. Locally orderless registration code

    DEFF Research Database (Denmark)

    2012-01-01

    This is code for the TPAMI paper "Locally Orderless Registration". The code requires intel threadding building blocks installed and is provided for 64 bit on mac, linux and windows.......This is code for the TPAMI paper "Locally Orderless Registration". The code requires intel threadding building blocks installed and is provided for 64 bit on mac, linux and windows....

  10. Vertical variation of atrazine mineralization capacity in soils Variación vertical de la capacidad de mineralización de atrazina en suelos

    Directory of Open Access Journals (Sweden)

    S. Hang

    2007-12-01

    Full Text Available The variation of atrazine mineralization capacity was investigated in two soil profiles selected with (adapted soil and without (non-adapted soil atrazine application history in Córdoba, Argentina. Atrazine evolution was characterized by balance of 14C-U-ring atrazine radioactivity between mineralized, extractable and non-extractable fractions by means of incubations under laboratory conditions in two soil situations: with dry heat treatment (T105 and without heat treatment (Control. The strong decrease of atrazine mineralization after microbial inactivation during all the incubation period in adapted soil suggests that the atrazine degraders were distributed throughout the entire adapted soil profile and were responsible for atrazine mineralization in subsurface horizons. In the non-adapted soil profile, the cometabolic process of mineralizing atrazine was corroborated. The atrazine mineralization capacity of subsurface horizons, where herbicide accumulation increases, should be considered and stimulated as a mechanism for the natural bioremediation of soils with frequent atrazine application.Se estudió la variación de la capacidad de mineralización de atrazina en dos suelos de la provincia de Córdoba, Argentina. Se seleccionaron dos perfiles de suelos con (suelo adaptado y sin (suelo no adaptado historia de aplicación de atrazina. La evolución de atrazina fue caracterizada mediante el balance de la radioactividad del 14C del anillo triazínico identificando las fracciones mineralizada, extractable y no extractable, durante incubaciones en condiciones de laboratorio con suelo tratado con calor (T105 y sin él (Control. La disminución de la capacidad de degradación de atrazina después de la inactivación microbiana y la limitada recuperación de esa capacidad observada en el perfil de suelo adaptado sugirió que los microorganismos degradadores de atrazina estarían distribuidos en todo el perfil siendo los responsables de la

  11. Effects of an atrazine, metolachlor and fipronil mixture on Hyalella azteca (Saussure) in a modified backwater wetland.

    Science.gov (United States)

    Lizotte, Richard E; Knight, Scott S; Shields, F Douglas; Bryant, Charles T

    2009-12-01

    We examined the toxicity mitigation efficiency of a hydrologically modified backwater wetland amended with a pesticide mixture of atrazine, metolachlor, and fipronil, using 96 h survival bioassays with Hyalella azteca. Significant H. azteca 96 h mortality occurred within the first 2 h of amendment at the upstream amendment site but not at any time at the downstream site. H. azteca survival varied spatially and temporally in conjunction with measured pesticide mixture concentrations. Hyalella azteca 96 h survival pesticide mixture effects concentrations ranges were 10.214–11.997, 5.822–6.658, 0.650–0.817, and 0.030–0.048 μg L−1 for atrazine, metolachlor, fipronil, and fipronil-sulfone, respectively.

  12. Sublethal effects of atrazine and glyphosate on life history traits of Aedes aegypti and Aedes albopictus (Diptera: Culicidae).

    Science.gov (United States)

    Bara, Jeffrey J; Montgomery, Allison; Muturi, Ephantus J

    2014-08-01

    Although exposure of mosquito larvae to agricultural chemicals such as herbicides is common and widespread, our understanding of how these chemicals affect mosquito ecology and behavior is limited. This study investigated how an environmentally relevant concentration of two herbicides, atrazine and glyphosate, affects mosquito life history traits. One hundred and fifty (150) first instar Aedes (Stegomyia) aegypti (L.) or Aedes (Stegomyia) albopictus (Skuse) larvae were reared in 1.6 L of live oak leaf (Quercus virginiana) infusion in the presence (5 mg/L) or absence (0 mg/L) of atrazine or glyphosate. The containers were monitored daily to determine the emergence rates, sex ratio, male and female emergence times, and female body size. Emergence rates of A. aegypti from atrazine treatment were significantly higher relative to either glyphosate or control treatments (A. aegypti: atrazine = 93 ± 6% (±95% CI), glyphosate = 82 ± 5%, control = 78 ± 5%), while emergence rates of A. albopictus in atrazine treatments were significantly higher than in glyphosate treatments but not in controls (A. albopictus: atrazine = 84 ± 5 %, glyphosate = 76 ± 4%, control = 78 ± 4%). For both mosquito species, a sex ratio distortion with male bias was observed in control and glyphosate treatments, but not in atrazine treatments (A. aegypti: atrazine = 0.90 ± 0.17 (±SE), glyphosate = 1.63 ± 0.21, control = 1.69 ± 0.26; A. albopictus: atrazine = 1.09 ± 0.08, glyphosate = 1.88 ± 0.12, control = 1.37 ± 0.11). Emergence times for both sexes of the two mosquito species were significantly longer in atrazine treatments compared to glyphosate or control treatments (A. aegypti: females: atrazine = 11.20 ± 0.50 (days ± 95 % CI), glyphosate = 9.71 ± 0.23, control = 9.87 ± 0.21; males: atrazine = 9.46 ± 0.27, glyphosate = 8.80 ± 0.25, control

  13. Liquid-liquid extraction assisted by a carbon nanoparticles interface. Electrophoretic determination of atrazine in environmental samples.

    Science.gov (United States)

    Caballero-Díaz, Encarnación; Simonet, Bartolomé; Valcárcel, Miguel

    2013-10-21

    A novel method for the determination of atrazine, using liquid-liquid extraction assisted by a nanoparticles film formed in situ and composed of organic solvent stabilized-carbon nanoparticles, is described. The presence of nanoparticles located at the liquid-liquid interface reinforced the extraction of analyte from matrix prior to capillary electrophoresis (CE) analysis. Some influential experimental variables were optimized in order to enhance the extraction efficiency. The developed procedure confirmed that carbon nanoparticles, especially multi-walled carbon nanotubes, are suitable to be used in sample treatment processes introducing new mechanisms of interaction with the analyte. The application of the proposed preconcentration method followed by CE detection enabled the determination of atrazine in spiked river water providing acceptable RSD values (11.6%) and good recoveries (about 87.0-92.0%). Additionally, a similar extraction scheme was tested in soil matrices with a view to further applications in real soil samples.

  14. QR Codes 101

    Science.gov (United States)

    Crompton, Helen; LaFrance, Jason; van 't Hooft, Mark

    2012-01-01

    A QR (quick-response) code is a two-dimensional scannable code, similar in function to a traditional bar code that one might find on a product at the supermarket. The main difference between the two is that, while a traditional bar code can hold a maximum of only 20 digits, a QR code can hold up to 7,089 characters, so it can contain much more…

  15. Constructing quantum codes

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Quantum error correcting codes are indispensable for quantum information processing and quantum computation.In 1995 and 1996,Shor and Steane gave first several examples of quantum codes from classical error correcting codes.The construction of efficient quantum codes is now an active multi-discipline research field.In this paper we review the known several constructions of quantum codes and present some examples.

  16. Epitaxial growth and electronic properties of well ordered phthalocyanine heterojunctions MnPc/F{sub 16}CoPc

    Energy Technology Data Exchange (ETDEWEB)

    Lindner, Susi; Mahns, Benjamin; Treske, Uwe; Knupfer, Martin [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Vilkov, Oleg [Center for Physical Methods of Surface Investigation, St. Petersburg State University, Ulyanovskaya Str. 1, St. Petersburg 198504, Russia and Institute of Solid State Physics, University of Technology Dresden, Zellescher Weg 16, D-01062 Dresden (Germany); Haidu, Francisc; Fronk, Michael; Zahn, Dietrich R. T. [Physics Department/Semiconductor Physics, Chemnitz University of Technology, Reichenhainer Str. 70, D-09126 Chemnitz (Germany)

    2014-09-07

    We have prepared phthalocyanine heterojunctions out of MnPc and F{sub 16}CoPc, which were studied by means of X-ray absorption spectroscopy. This heterojunction is characterized by a charge transfer at the interface, resulting in charged MnPc{sup δ} {sup +} and F{sub 16}CoPc{sup δ} {sup −} species. Our data reveal that the molecules are well ordered and oriented parallel to the substrate surface. Furthermore, we demonstrate the filling of the Co 3d{sub z{sup 2}} orbital due to the charge transfer, which supports the explanation of the density functional theory, that the charge transfer is local and affects the metal centers only.

  17. Gifted and Non-Identified as Gifted Students’ Preferred PC Game Types and PC Game Perceptions: A Descriptive Study

    Directory of Open Access Journals (Sweden)

    Hakan ÜSTÜNEL

    2016-12-01

    Full Text Available Computer games have gained a significance role in students’ daily life. Games also play an important role in PC technologies development and progress. In addition to the entertainment aspects of PC games, they are now being used in educational environments. The aim of the research is to determine gifted students' and that giftedness diagnostics not defined before, PC game types preference. With this aim, literature review on the subject has been conducted. 47 gifted students from Istanbul Science and Art Center have formed the sample group. 818 students from 16 different state schools attended by the gifted students have been included in the study. Aim of this study is to compare the difference in the perceptions of the gifted and the other students. The data were collected through a questionnaire. They were analyzed using descriptive statistics and the study reveals that the gifted students and non-identified students differentiate in preferences of PC games types.

  18. CoPc and CoPcF16 on gold: Site-specific charge-transfer processes

    Directory of Open Access Journals (Sweden)

    Fotini Petraki

    2014-04-01

    Full Text Available Interface properties of cobalt(II phthalocyanine (CoPc and cobalt(II hexadecafluoro-phthalocyanine (CoPcF16 to gold are investigated by photo-excited electron spectroscopies (X-ray photoemission spectroscopy (XPS, ultraviolet photoemission spectroscopy (UPS and X-ray excited Auger electron spectroscopy (XAES. It is shown that a bidirectional charge transfer determines the interface energetics for CoPc and CoPcF16 on Au. Combined XPS and XAES measurements allow for the separation of chemical shifts based on different local charges at the considered atom caused by polarization effects. This facilitates a detailed discussion of energetic shifts of core level spectra. The data allow the discussion of site-specific charge-transfer processes.

  19. Semifield testing of a bioremediation tool for atrazine-contaminated soils: evaluating the efficacy on soil and aquatic compartments.

    Science.gov (United States)

    Chelinho, Sónia; Moreira-Santos, Matilde; Silva, Cátia; Costa, Catarina; Viana, Paula; Viegas, Cristina A; Fialho, Arsénio M; Ribeiro, Rui; Sousa, José Paulo

    2012-07-01

    The present study evaluated the bioremediation efficacy of a cleanup tool for atrazine-contaminated soils (Pseudomonas sp. ADP plus citrate [P. ADP + CIT]) at a semifield scale, combining chemical and ecotoxicological information. Three experiments representing worst-case scenarios of atrazine contamination for soil, surface water (due to runoff), and groundwater (due to leaching) were performed in laboratory simulators (100 × 40 × 20 cm). For each experiment, three treatments were set up: bioremediated, nonbioremediated, and a control. In the first, the soil was sprayed with 10 times the recommended dose (RD) for corn of Atrazerba and with P. ADP + CIT at day 0 and a similar amount of P. ADP at day 2. The nonbioremediated treatment consisted of soil spraying with 10 times the RD of Atrazerba (day 0). After 7 d of treatment, samples of soil (and eluates), runoff, and leachate were collected for ecotoxicological tests with plants (Avena sativa and Brassica napus) and microalgae (Pseudokirchneriella subcapitata) species. In the nonbioremediated soils, atrazine was very toxic to both plants, with more pronounced effects on plant growth than on seed emergence. The bioremediation tool annulled atrazine toxicity to A. sativa (86 and 100% efficacy, respectively, for seed emergence and plant growth). For B. napus, results point to incomplete bioremediation. For the microalgae, eluate and runoff samples from the nonbioremediated soils were extremely toxic; a slight toxicity was registered for leachates. After only 7 d, the ecotoxicological risk for the aquatic compartments seemed to be diminished with the application of P. ADP + CIT. In aqueous samples obtained from the bioremediated soils, the microalgal growth was similar to the control for runoff samples and slightly lower than control (by 11%) for eluates.

  20. Group Control System by PC and PLC%PC-PLC组成的电梯群控系统

    Institute of Scientific and Technical Information of China (English)

    唐勇奇; 赵葵银

    2001-01-01

    介绍一种由PC与PLC组成的电梯群控系统,讲述了系统的软件设计方法和PLC与PC之间的通讯方案。%This paper introduced the group control system of an elevator control system with PC and PLC and also described the design of its software and the communication method between PLC and PC.

  1. PC Tutor. Bericht uber ein PC-gestutzes Tutorensystem = PC Tutor. Report on a Tutoring System with Personal Computer. ZIFF Papiere 75.

    Science.gov (United States)

    Fritsch, Helmut

    A project was conducted to increase as well as to professionalize communication between tutors and learners in a West German university's distance education program by the use of personal computers. Two tutors worked on the systematic development of a PC-based correcting system. The goal, apart from developing general language skills in English,…

  2. Relation of Landscape Position and Irrigation to Concentrations of Alachlor, Atrazine, and Selected Degradates in Regolith in Northeastern Nebraska

    Science.gov (United States)

    Verstraeten, Ingrid M.; Lewis, D.T.; McCallister, D.L.; Parkhurst, A.; Thurman, E.M.

    1996-01-01

    Concentrations of alachlor, its ethanesulfonic acid degradate, atrazine and its degradates, deethylatrazine and deisopropylatrazine, in the upper regolith and associated shallow aquifers were determined in relation to landscape position (floodplains, terraces, and uplands) and irrigation (nonirrigated and irrigated corn cropland) in 1992. Irrigated and nonirrigated sites were located on each landscape position. Samples were collected from three depths. Canonical discriminant and multivariate analyses were used to interpret data. Herbicides and their degradation products tended to be present in soils with high percent organic matter, low pH, and low sand content. Atrazine was present more frequently on the floodplain at all depths than the other compounds. Atrazine (maximum 17.5 ??g/kg) and ethanesulfonic acid (maximum 10 ??g/kg) were associated with landscape position, but not with irrigation. Alachlor (maximum 24 ??g/kg), deethylatrazine (maximum 1.5 ??g/kg), and deisopropylatrazine (maximum 3.5 ??g/kg) were not significantly associated with either landscape position or irrigation. Ground-water analytical results suggested that concentrations of these herbicides and degradates in ground water did not differ among landscape position or between irrigated and nonirrigated corn cropland.

  3. s-triazine degrading bacterial isolate Arthrobacter sp. AK-YN10, a candidate for bioaugmentation of atrazine contaminated soil.

    Science.gov (United States)

    Sagarkar, Sneha; Bhardwaj, Pooja; Storck, Veronika; Devers-Lamrani, Marion; Martin-Laurent, Fabrice; Kapley, Atya

    2016-01-01

    The Arthrobacter sp. strain AK-YN10 is an s-triazine pesticide degrading bacterium isolated from a sugarcane field in Central India with history of repeated atrazine use. AK-YN10 was shown to degrade 99 % of atrazine in 30 h from media supplemented with 1000 mg L(-1) of the herbicide. Draft genome sequencing revealed similarity to pAO1, TC1, and TC2 catabolic plasmids of the Arthrobacter taxon. Plasmid profiling analyses revealed the presence of four catabolic plasmids. The trzN, atzB, and atzC atrazine-degrading genes were located on a plasmid of approximately 113 kb.The flagellar operon found in the AK-YN10 draft genome suggests motility, an interesting trait for a bioremediation agent, and was homologous to that of Arthrobacter chlorophenolicus. The multiple s-triazines degradation property of this isolate makes it a good candidate for bioremediation of soils contaminated by s-triazine pesticides.

  4. Tantalum (oxy)nitrides: preparation, characterisation and enhancement of photo-Fenton-like degradation of atrazine under visible light.

    Science.gov (United States)

    Du, Yingxun; Zhao, Lu; Su, Yaling

    2011-11-15

    Tantalum (oxy)nitrides were prepared by the nitridation of Ta(2)O(5) and were added to a photo-Fenton-like system to enhance Fe(3+) reduction and atrazine degradation under visible light. The samples were characterized by XRD, XPS, DRS and BET analyses. XPS analysis showed that the nitrogen content of the tantalum (oxy)nitride samples increased noticeably with the nitridation temperature and nitridation time but slightly with the flow rate of NH(3). XRD results showed Ta(2)O(5) was first converted to TaON and then to Ta(3)N(5) when the nitridation temperature increased. DRS analysis showed that the sample obtained at 800°C displayed the strongest absorption of visible light. However, the ability of the tantalum (oxy)nitrides to reduce Fe(3+) did not increase continuously with the nitrogen content. Sample 7 (700°C, [Formula: see text] , 6h) showed the highest level of photocatalytic activity for Fe(3+) reduction. This is because the photocatalytic activity of TaON for Fe(3+) reduction is higher than that of Ta(3)N(5). And a slight synergetic effect was observed between TaON and Ta(3)N(5). With the addition of sample 7, H(2)O(2) decomposition and atrazine degradation were significantly accelerated in a photo-Fenton-like system under visible light. The regenerated tantalum (oxy)nitrides catalyst displayed considerably stable performance for atrazine degradation.

  5. Kinetic and isotherm error optimization studies for adsorption of atrazine and imidacloprid on bark of Eucalyptus tereticornis L.

    Science.gov (United States)

    Mandal, Abhishek; Singh, Neera

    2016-01-01

    The aim of this study was to establish the bark of Eucalyptus tereticornis L. (EB) as a low cost bio-adsorbent for the removal of imidacloprid and atrazine from aqueous medium. The pseudo-first-order (PFO), pseudo-second-order (PSO), Elovich and intra-particle diffusion (IPD) models were used to describe the kinetic data and rate constants were evaluated. Adsorption data was analysed using ten 2-, 3- and 4-parameter models viz. Freundlich, Jovanovic, Langmuir, Temkin, Koble-Corrigan, Redlich-Peterson, Sips, Toth, Radke-Prausnitz, and Fritz-Schluender isotherms. Six error functions were used to compute the best fit single component isotherm parameters by nonlinear regression analysis. The results showed that the sorption of atrazine was better explained by PSO model, whereas the sorption of imidacloprid followed the PFO kinetic model. Isotherm model optimization analysis suggested that the Freundlich along with Koble-Corrigan, Toth and Fritz-Schluender were the best models to predict atrazine and imidacloprid adsorption onto EB. Error analysis suggested that minimization of chi-square (χ(2)) error function provided the best determination of optimum parameter sets for all the isotherms.

  6. Antioxidant and neurotoxicity markers in the model organism Enchytraeus albidus (Oligochaeta): mechanisms of response to atrazine, dimethoate and carbendazim.

    Science.gov (United States)

    Novais, Sara C; Gomes, Nuno C; Soares, Amadeu M V M; Amorim, Mónica J B

    2014-09-01

    The present study aimed to investigate the effects of dimethoate, atrazine and carbendazim on the antioxidant defences and neuronal function of the soil organism Enchytraeus albidus. Effects were studied at concentrations known to affect their reproduction (EC20, EC50 and EC90) and along time (2, 4, 8, 14 and 21 days). In general, responses were more pronounced at periods of exposure longer than 8 days and at the highest concentrations. Multivariate statistics (RDA-PRC) clearly displayed that exposure duration had an effect itself, biomarkers' responses showed interaction for all pesticides and catalase scored consistently high, indicating its relevancy in the group of measured markers. Univariate analysis indicated oxidative stress for all pesticides and atrazine induced oxidative damage in lipids. Atrazine seems to be effectively metabolized by GST of the biotransformation system, as its activity significantly increased after exposure to this pesticide. Dimethoate caused ChE inhibition, indicating an impairment of the neuronal function. Carbendazim impaired the antioxidant system, but no oxidative damage was observed, along with any effects on the ChE activity. The integrated biomarker response analysis was performed but we suggest modifications due to limiting artefacts.

  7. Effects of atrazine on egg masses of the yellow-spotted salamander (Ambystoma maculatum) and its endosymbiotic alga (Oophila amblystomatis).

    Science.gov (United States)

    Baxter, Leilan; Brain, Richard A; Hosmer, Alan J; Nema, Mohini; Müller, Kirsten M; Solomon, Keith R; Hanson, Mark L

    2015-11-01

    Embryonic growth of the yellow-spotted salamander (Ambystoma maculatum) is enhanced by the presence of the green alga Oophila amblystomatis, in the egg capsule. To further assess potential impacts of herbicides on this relationship, A. maculatum egg masses were exposed to atrazine (0-338 μg/L) until hatching (up to 66 days). Exposure to atrazine reduced PSII yield of the symbiotic algae in a concentration-dependent manner, but did not significantly affect visible algal growth or any metrics associated with salamander development. Algal cells were also cultured in the laboratory for toxicity testing. In the 96-h growth inhibition test (0-680 μg/L), ECx values were generally greater than those reported for standard algal test species. Complete recovery of growth rates occurred within 96-h of transferring cells to untreated media. Overall, development of A. maculatum embryos was not affected by exposure to atrazine at concentrations and durations exceeding those found in the environment.

  8. Atrazine and malathion shorten the maturation process of Xenopus laevis oocytes and have an adverse effect on early embryo development.

    Science.gov (United States)

    Ji, Qichao; Lee, Jessica; Lin, Yu-Huey; Jing, Guihua; Tsai, L Jillianne; Chen, Andrew; Hetrick, Lindsay; Jocoy, Dylan; Liu, Junjun

    2016-04-01

    The use of pesticides has a negative impact on the environment. Amphibians have long been regarded as indicator species to pollutants due to their permeable skin and sensitivity to the environment. Studies have shown that population declines of some amphibians are directly linked with exposure to agricultural contaminants. In the past, much of the studies have focused on the toxic effect of contaminants on larvae (tadpoles), juvenile and adult frogs. However, due to the nature of their life cycle, amphibian eggs and early embryos are especially susceptible to the contaminants, and any alteration during the early reproductive stages may have a profound effect on the health and population of amphibians. In this study, we analyzed the effect of atrazine and malathion, two commonly used pesticides, on Xenopus laevis oocyte maturation and early embryogenesis. We found that both atrazine and malathion shortened the frog oocyte maturation process and resulted in reduced Emi2 levels at cytostatic factor-mediated metaphase arrest, and a high level of Emi2 is critically important for oocyte maturation. Furthermore, frog embryos fertilized under the influence of atrazine and/or malathion displayed a higher rate of abnormal division that eventually led to embryo death during early embryogenesis.

  9. User's guide and documentation manual for BOAST-VHS for the PC''

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Ming-Ming; Sarathi, P.; Heemstra, R.J.; Cheng, A.M.; Pautz, J.F.

    1992-01-01

    The recent advancement of computer technology makes reservoir simulations feasible in a personal computer (PC) environment. This manual provides a guide for running BOAST-VHS, a black oil reservoir simulator for vertical/horizontal/slant wells, using a PC. In addition to detailed explanations of input data file preparation for simulation runs, special features of BOAST-VHS are described and three sample problems are presented. BOAST-VHS is a cost-effective and easy-to-use reservoir simulation tool for the study of oil production from primary depletion and waterflooding in a black oil reservoir. The well model in BOAST-VHS permits specification of any combination of horizontal, slanted, and vertical wells in the reservoir. BOAST-VHS was designed for an IBM PC/AT, PS-2, or compatible computer with 640 K bytes of memory. BOAST-VHS can be used to model a three-dimensional reservoir of up to 810 grid blocks with any combination of rows, columns, and layers, depending on the input data supplied. This dynamic redimensioning feature facilitates simulation work by avoiding the need to recompiling the simulator for different reservoir models. Therefore the program is only supplied as executable code without any source code.

  10. Assessment of periphyton, aquatic macrophytes, benthic communities, and physical habitat in midwestern United States streams coinciding with varying historical concentrations of atrazine.

    Science.gov (United States)

    Hall, Lenwood W; Anderson, Ronald D; Killen, William D; Hosmer, Alan J; Brain, Richard A

    2014-01-01

    The objectives of this pilot study were to: (1) characterize periphyton and benthic communities using standard collection methods in six Midwest watersheds with varying historical levels of atrazine (low range, medium range and upper range); (2) qualitatively assess presence of aquatic vascular plants at each site; (3) assess and compare physical habitat at each study site in order to evaluate how physical habitat structure may influence the biological communities and (4) analyze the periphyton and benthic macroinvertebrate community data (i.e., series of metrics) among sites to evaluate possible differences or similarities among sites with different historical atrazine exposures. Five of the eight physical habitat metrics (including total physical habitat score) were different among the six study sites. There appeared to be no substantial difference in the structure of periphtyon communities at the six Midwest sites based on 9 of 12 metrics. For the three metrics that showed differences among sites-percentage of sensitive diatoms, percent Achnanches minutissima and percent motile diatoms - there was no consistent pattern with previous degrees of atrazine exposure and the scoring of these metrics. There were also no statistical differences in aquatic macrophyte spatial coverage among the six study areas. Thus, based on the spatially and temporally limited periphyton and aquatic macrophyte data, varying historical atrazine exposure was not associated with impact on resident plant communities (the target receptor group for atrazine). All 10 benthic community metrics showed significant differences among the six Midwest sites. Although no consistent pattern existed with varying historic levels of atrazine, benthic communities at one site with lower historical levels of atrazine were of higher quality than the other five sites. However, this one site also had a higher quality habitat compared to the other sites which was most likely the reason for this benthic condition.

  11. Isolation and characterization of atrazine-degrading Arthrobacter sp. AD26 and use of this strain in bioremediation of contaminated soil

    Institute of Scientific and Technical Information of China (English)

    LI Qingyan; LI Ying; ZHU Xikun; CAI Baoli

    2008-01-01

    A bacterial strain (AD26) capable of utilizing atrazine as a sole nitrogen source for growth was isolated from an industrial wastewatersample by enrichment culture. The 16S rRNA gene sequencing identified AD26 as anArthrobacter sp. PCR assays indicated that AD26contained atrazine-degrading genes trzN and atzBC. The trzN gene of AD26 only differs from the trzN ofArthrobacter aurescens TC1by one base (A→T at 907) and one amino acid (Met→Leu at 303). The specific activity of trzN of AD26 in crude cell extract was0.28 U/mg, which was 1.2 times that of TC 1. This strain has shown faster growth and atrazine-degradation rates in atrazine-containingminimal media than two well characterized atrazine-degrading bacteria, Pseudomonas sp. ADP and Arthrobacter aurescens TC 1. Afterincubating for 48 h at 30℃, the OD600 of AD26 reached 2.6 compared with 1.33 of ADP. AD26 was capable of degrading 500 mg/Lof atrazine in minimal medium at 95% in 72 h, while the degradative rates by TC1 and ADP were only 90% and 86%, respectively. Abioremediation trial of contaminated soil has indicated that AD26 can degrade as high as 98% of atrazine contained in soil (300 mg/kg)after incubating for 20 d at 26℃, nominating this strain as a good candidate for use in bioremediation programs.

  12. GABAA receptor-mediated feedforward and feedback inhibition differentially modulate the gain and the neural code transformation in hippocampal CA1 pyramidal cells.

    Science.gov (United States)

    Jang, Hyun Jae; Park, Kyerl; Lee, Jaedong; Kim, Hyuncheol; Han, Kyu Hun; Kwag, Jeehyun

    2015-12-01

    Diverse variety of hippocampal interneurons exists in the CA1 area, which provides either feedforward (FF) or feedback (FB) inhibition to CA1 pyramidal cell (PC). However, how the two different inhibitory network architectures modulate the computational mode of CA1 PC is unknown. By investigating the CA3 PC rate-driven input-output function of CA1 PC using in vitro electrophysiology, in vitro-simulation of inhibitory network, and in silico computational modeling, we demonstrated for the first time that GABAA receptor-mediated FF and FB inhibition differentially modulate the gain, the spike precision, the neural code transformation and the information capacity of CA1 PC. Recruitment of FF inhibition buffered the CA1 PC spikes to theta-frequency regardless of the input frequency, abolishing the gain and making CA1 PC insensitive to its inputs. Instead, temporal variability of the CA1 PC spikes was increased, promoting the rate-to-temporal code transformation to enhance the information capacity of CA1 PC. In contrast, the recruitment of FB inhibition sub-linearly transformed the input rate to spike output rate with high gain and low spike temporal variability, promoting the rate-to-rate code transformation. These results suggest that GABAA receptor-mediated FF and FB inhibitory circuits could serve as network mechanisms for differentially modulating the gain of CA1 PC, allowing CA1 PC to switch between different computational modes using rate and temporal codes ad hoc. Such switch will allow CA1 PC to efficiently respond to spatio-temporally dynamic inputs and expand its computational capacity during different behavioral and neuromodulatory states in vivo.

  13. Empirically modelled Pc3 activity based on solar wind parameters

    Directory of Open Access Journals (Sweden)

    T. Raita

    2010-09-01

    Full Text Available It is known that under certain solar wind (SW/interplanetary magnetic field (IMF conditions (e.g. high SW speed, low cone angle the occurrence of ground-level Pc3–4 pulsations is more likely. In this paper we demonstrate that in the event of anomalously low SW particle density, Pc3 activity is extremely low regardless of otherwise favourable SW speed and cone angle. We re-investigate the SW control of Pc3 pulsation activity through a statistical analysis and two empirical models with emphasis on the influence of SW density on Pc3 activity. We utilise SW and IMF measurements from the OMNI project and ground-based magnetometer measurements from the MM100 array to relate SW and IMF measurements to the occurrence of Pc3 activity. Multiple linear regression and artificial neural network models are used in iterative processes in order to identify sets of SW-based input parameters, which optimally reproduce a set of Pc3 activity data. The inclusion of SW density in the parameter set significantly improves the models. Not only the density itself, but other density related parameters, such as the dynamic pressure of the SW, or the standoff distance of the magnetopause work equally well in the model. The disappearance of Pc3s during low-density events can have at least four reasons according to the existing upstream wave theory: 1. Pausing the ion-cyclotron resonance that generates the upstream ultra low frequency waves in the absence of protons, 2. Weakening of the bow shock that implies less efficient reflection, 3. The SW becomes sub-Alfvénic and hence it is not able to sweep back the waves propagating upstream with the Alfvén-speed, and 4. The increase of the standoff distance of the magnetopause (and of the bow shock. Although the models cannot account for the lack of Pc3s during intervals when the SW density is extremely low, the resulting sets of optimal model inputs support the generation of mid latitude Pc3 activity predominantly through

  14. Determining design and scale-up parameters for degradation of atrazine with suspended Pseudomonas sp. ADP in aqueous bioreactors.

    Science.gov (United States)

    Biglione, Nicole; Rodgers, V G J; Peeples, Tonya L

    2008-01-01

    This work investigated the kinetic parameters of atrazine mineralization by suspended cells of Pseudomonas sp. ADP in both shake flasks and spherical stirred tank batch reactors (SSTR). The degradation of atrazine and growth of Pseudomonas sp. ADP were studied. Experiments were performed at different temperatures and stirring speeds in both reactors at varying initial concentrations of atrazine. Cell growth and atrazine concentration were monitored over time, and a Monod model with one limiting substrate was used to characterize the kinetic behavior. Temperature, stirring speed, and reactor type were all found to significantly affect the regressed Monod parameters. At 27 degrees C and 200 rpm, for the shaker flask experiments, mu max and Ks were determined to be 0.14 (+/-0.01) h-1 and 1.88 (+/-1.80) mg/L, respectively. At 37 degrees C, mu max and Ks increased to 0.25 (+/-0.05) h-1 and 9.59 (+/-6.55) mg/L, respectively. As expected, stirrer speed was also found to significantly alter the kinetic parameters. At 27 degrees C and 125 rpm, mu max and Ks were 0.04 (+/-0.002) h-1 and 3.72 (+/-1.05) mg/L, respectively, whereas at 37 degrees C and 125 rpm, mu max and Ks were 0.07 (+/-0.008) h-1 and 1.65 (+/-2.06) mg/L. In the SSTR the kinetic parameters mu max and Ks at room temperature were determined to be 0.12 (+/-0.009) h-1 and 2.18 (+/-0.47) mg/L, respectively. Although the mu max values for both types of reactors were similar, the shaker flask experiments resulted in considerable error. Error analysis on calculated values of Ks were found to impact estimates in atrazine concentration by as much as two orders of magnitude, depending on the reactor design, illustrating the importance of these factors in reactor scale-up.

  15. Tantalum (oxy)nitrides nanotube arrays for the degradation of atrazine in vis-Fenton-like process

    Energy Technology Data Exchange (ETDEWEB)

    Du, Yingxun, E-mail: yxdu@niglas.ac.cn [Nanjing Institute of Geography and Limnology, State Key Laboratory of Lake Science and Environment, Chinese Academy of Sciences, Nanjing 210008 (China); Zhao, Lu [Nanjing Institute of Geography and Limnology, State Key Laboratory of Lake Science and Environment, Chinese Academy of Sciences, Nanjing 210008 (China); Chang, Yuguang [School of Biochemical and Environmental Engineering, Nanjing Xiaozhuang Univeristy, Nanjing 211171 (China); Su, Yaling [Nanjing Institute of Geography and Limnology, State Key Laboratory of Lake Science and Environment, Chinese Academy of Sciences, Nanjing 210008 (China)

    2012-07-30

    Highlights: Black-Right-Pointing-Pointer Tantala nanotubes on a Ta foil were formed by anodization in a NH{sub 4}F-containing electrolyte. Black-Right-Pointing-Pointer Tantalum (oxy)nitrides nanotubes were active for Fe{sup 3+} reduction under visible light. Black-Right-Pointing-Pointer Atrazine degradation by {center_dot}OH was accelerated with tantalum (oxy)nitrides nanotubes. Black-Right-Pointing-Pointer Tantalum (oxy)nitrides nanotubes display stable performance for atrazine degradation. - Abstract: In order to overcome the limitation of the application of nanoparticles, tantalum (oxy)nitrides nanotube arrays on a Ta foil were synthesized and introduced in vis (visible light)-Fenton-like system to enhance the degradation of atrazine. At first, the anodization of tantalum foil in a mild electrolyte solution containing ethylene glycol and water (v:v = 2:1) plus 0.5 wt.% NH{sub 4}F produced tantala nanotubes with an average diameter of 30 nm and a length of approximately 1 {mu}m. Then the nitridation of tantala nanotube arrays resulted in the replacement of N atoms to O atoms to form tantalum (oxy)nitrides (TaON and Ta{sub 3}N{sub 5}), as testified by XRD and XPS analyses. The synthesized tantalum (oxy)nitrides nanotubes absorb well in the visible region up to 600 nm. Under visible light, tantalum (oxy)nitrides nanotube arrays were catalytically active for Fe{sup 3+} reduction. With tantalum (oxy)nitrides nanotube arrays, the degradation of atrazine and the formation of the intermediates in vis/Fe{sup 3+}/H{sub 2}O{sub 2} system were significantly accelerated. This was explained by the higher concentration of Fe{sup 2+} and thus the faster decomposition of H{sub 2}O{sub 2} with tantalum (oxy)nitrides nanotubes. In addition, tantalum (oxy)nitrides nanotubes exhibited stable performance during atrazine degradation for three runs. The good performance and stability of the tantalum (oxy)nitrides nanotubes film with the convenient separation, suggest that this film is

  16. Tantalum (oxy)nitrides: Preparation, characterisation and enhancement of photo-Fenton-like degradation of atrazine under visible light

    Energy Technology Data Exchange (ETDEWEB)

    Du, Yingxun, E-mail: yxdu@niglas.ac.cn [Nanjing Institute of Geography and Limnology, State Key Laboratory of Lake Science and Environment, Chinese Academy of Sciences, Nanjing 210008 (China); Zhao, Lu; Su, Yaling [Nanjing Institute of Geography and Limnology, State Key Laboratory of Lake Science and Environment, Chinese Academy of Sciences, Nanjing 210008 (China)

    2011-11-15

    Highlights: {yields} The photocatalytic activity of TaON for Fe{sup 3+} reduction is higher than that of Ta{sub 3}N{sub 5}. {yields} Atrazine degradation was accelerated significantly by tantalum (oxy)nitrides sample. {yields} The regenerated catalyst displays considerably stable performance for atrazine degradation. - Abstract: Tantalum (oxy)nitrides were prepared by the nitridation of Ta{sub 2}O{sub 5} and were added to a photo-Fenton-like system to enhance Fe{sup 3+} reduction and atrazine degradation under visible light. The samples were characterized by XRD, XPS, DRS and BET analyses. XPS analysis showed that the nitrogen content of the tantalum (oxy)nitride samples increased noticeably with the nitridation temperature and nitridation time but slightly with the flow rate of NH{sub 3}. XRD results showed Ta{sub 2}O{sub 5} was first converted to TaON and then to Ta{sub 3}N{sub 5} when the nitridation temperature increased. DRS analysis showed that the sample obtained at 800 {sup o}C displayed the strongest absorption of visible light. However, the ability of the tantalum (oxy)nitrides to reduce Fe{sup 3+} did not increase continuously with the nitrogen content. Sample 7 (700 {sup o}C, Q{sub NH{sub 3}}=0.3L/min, 6 h) showed the highest level of photocatalytic activity for Fe{sup 3+} reduction. This is because the photocatalytic activity of TaON for Fe{sup 3+} reduction is higher than that of Ta{sub 3}N{sub 5}. And a slight synergetic effect was observed between TaON and Ta{sub 3}N{sub 5}. With the addition of sample 7, H{sub 2}O{sub 2} decomposition and atrazine degradation were significantly accelerated in a photo-Fenton-like system under visible light. The regenerated tantalum (oxy)nitrides catalyst displayed considerably stable performance for atrazine degradation.

  17. Network coding for computing: Linear codes

    CERN Document Server

    Appuswamy, Rathinakumar; Karamchandani, Nikhil; Zeger, Kenneth

    2011-01-01

    In network coding it is known that linear codes are sufficient to achieve the coding capacity in multicast networks and that they are not sufficient in general to achieve the coding capacity in non-multicast networks. In network computing, Rai, Dey, and Shenvi have recently shown that linear codes are not sufficient in general for solvability of multi-receiver networks with scalar linear target functions. We study single receiver networks where the receiver node demands a target function of the source messages. We show that linear codes may provide a computing capacity advantage over routing only when the receiver demands a `linearly-reducible' target function. % Many known target functions including the arithmetic sum, minimum, and maximum are not linearly-reducible. Thus, the use of non-linear codes is essential in order to obtain a computing capacity advantage over routing if the receiver demands a target function that is not linearly-reducible. We also show that if a target function is linearly-reducible,...

  18. Practices in Code Discoverability

    CERN Document Server

    Teuben, Peter; Nemiroff, Robert J; Shamir, Lior

    2012-01-01

    Much of scientific progress now hinges on the reliability, falsifiability and reproducibility of computer source codes. Astrophysics in particular is a discipline that today leads other sciences in making useful scientific components freely available online, including data, abstracts, preprints, and fully published papers, yet even today many astrophysics source codes remain hidden from public view. We review the importance and history of source codes in astrophysics and previous efforts to develop ways in which information about astrophysics codes can be shared. We also discuss why some scientist coders resist sharing or publishing their codes, the reasons for and importance of overcoming this resistance, and alert the community to a reworking of one of the first attempts for sharing codes, the Astrophysics Source Code Library (ASCL). We discuss the implementation of the ASCL in an accompanying poster paper. We suggest that code could be given a similar level of referencing as data gets in repositories such ...

  19. Influence of the pesticides glyphosate, chlorpyrifos and atrazine on growth parameters of nonochratoxigenic Aspergillus section Nigri strains isolated from agricultural soils.

    Science.gov (United States)

    Carranza, Cecilia S; Barberis, Carla L; Chiacchiera, Stella M; Magnoli, Carina E

    2014-01-01

    This investigation was undertake to determine the effect of glyphosate, chlorpyrifos and atrazine on the lag phase and growth rate of nonochratoxigenic A. niger aggregate strains growing on soil extract medium at -0.70, -2.78 and -7.06 MPa. Under certain conditions, the glyphosate concentrations used significantly increased micelial growth as compared to control. An increase of about 30% was observed for strain AN 251 using 5 and 20 mg L(-1) of glyphosate at -2.78 MPa. The strains behaved differently in the presence of the insecticide chlorpyrifos. A significant decrease in growth rate, compared to control, was observed for all strains except AN 251 at -2.78 MPa with 5 mg L(-1). This strain showed a significant increase in growth rate. With regard to atrazine, significant differences were observed only under some conditions compared to control. An increase in growth rate was observed for strain AN 251 at -2.78 MPa with 5 and 10 mg L(-1) of atrazine. By comparison, a reduction of 25% in growth rate was observed at -7.06 MPa and higher atrazine concentrations. This study shows that glyphosate, chlorpyrifos and atrazine affect the growth parameters of nonochratoxigenic A. niger aggregate strains under in vitro conditions.

  20. Evaluation of PCR-based quantification techniques to estimate the abundance of atrazine chlorohydrolase gene atzA in rhizosphere soils.

    Science.gov (United States)

    Thompson, Brian M; Lin, Chung-Ho; Hsieh, Hsin-Yeh; Kremer, Robert J; Lerch, Robert N; Garrett, Harold E

    2010-01-01

    There are many challenges in the accurate quantification of bacterial genes, such as the atrazine-degrading enzyme antA from Pseudomonas sp. strain ADP, from soil samples. We compared four quantitative methods for enumeration of atrazine-degrading bacteria in rhizosphere environments and utilized the optimal probe-based real-time polymerase chain reaction (PCR)-based method in an ongoing bioremediation experiment to monitor atzA copy number over time. We compared three quantitative PCR (qPCR) based methods--quantitative competitive PCR and two real-time qPCR methods--to traditional dilution-plate counting techniques. The optimal real-time qPCR assay was then used to monitor atzA copy number over time in the robust atrazine-degrading Pseudomonas sp. strain ADP-spiked rhizosphere environment. The use of sensitive and reliable probe-based real-time qPCRs for the enumeration of bacterial catabolic genes allows for their detection from soil samples and monitoring of potential degradative populations over time. The addition of arrazine-biodegrading bacteria into arrazine-contaminated sites to remove entrapped atrazine is a promising approach for mitigating atrazine pollution and its metabolites. The methodology contained herein will allow for optimal monitoring of atzA in rhizosphere soil with or without the addition of biodegradative Pseudomonas sp. strain ADP of bacteria.