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Sample records for soil potential nitrite

  1. Controlled-potential iodometric titration of nitrite. Application to the determination of nitrite in meat products.

    Science.gov (United States)

    Karlsson, R; Torstensson, L G

    1974-09-01

    A controlled-potential coulometric method using iodine as an intermediate has been devised for the determination of nitrite. Nitrite is reduced by iodide and the iodine formed is then reduced coulometrically. The reduction of nitrite in the pH range 0-6 has been studied and the optimum conditions for an accurate determination are stated. The time of analysis for a determination in the range 0.005-5 mg of nitrite is about 2-5 min and the error +/- 0.1%. The method is applied to the determination of nitrite in some meat products.

  2. Nitrate ammonification in mangrove soils: a hidden source of nitrite?

    KAUST Repository

    Balk, Melike

    2015-03-02

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests. The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden by the presence of active nitrite-reducing microorganisms under the nitrate-limited conditions of most mangrove forest soils.

  3. Nitrate ammonification in mangrove soils: A hidden source of nitrite?

    Directory of Open Access Journals (Sweden)

    Melike eBalk

    2015-03-01

    Full Text Available Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests.The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden under the nitrate-limited conditions of most mangrove forest soils.

  4. Potential rates of ammonium oxidation, nitrite oxidation, nitrate reduction and denitrification in the young barley rhizosphere

    DEFF Research Database (Denmark)

    Højberg, Ole; Binnerup, S. J.; Sørensen, Jan

    1996-01-01

    Potential activities (enzyme contents) of ammonium (NH4+) oxidizing, nitrite (NO2-) oxidizing, nitrate (NO3-) reducing and denitrifying bacteria were measured in bulk and rhizosphere soil obtained from young barley plants in the field. The activities as well as pools of inorganic N (NH4+, NO2...

  5. PENGARUH PENAMBAHAN UREA TERHADAP PENINGKATAN PENCEMARAN NITRIT DAN NITRAT DALAM TANAH (Influence of Addition of Urea to Increased Pollution of Nitrite and Nitrate in The Soil

    Directory of Open Access Journals (Sweden)

    Aida Mawaddah

    2016-09-01

    Full Text Available ABSTRAK Nitrat dan nitrit merupakan sumber nitrogen bagi tanaman. Nitrogen sangat diperlukan tanaman untuk pertumbuhan dan perkembangan. Bentuk-bentuk nitrogen di lingkungan mengalami transformasi sebagai bagian dari siklus nitrogen seperti nitrifikasi dan denitrifikasi. Apabila kadar nitrogen dalam tanah rendah, maka urea digunakan sebagai sumber nitrogen. Perubahan urea menjadi nitrit atau nitrat pada beberapa sampel tanah perlu diketahui. Kadar nitrit dan nitrat yang tinggi dapat meningkatkan pencemaran di dalam tanah. Sampel tanah yang digunakan dalam penelitian ini adalah tanah pasir, tanah sawah, tanah pupuk kompos dan tanah pupuk kandang. Analisis nitrit dan nitrat dilakukan dengan menggunakan pereaksi asam p-amino benzoat (PABA yang dikopling dengan N-naftiletilendiamin (NEDA dan reduktor spongy cadmium. Sebelum digunakan untuk analisis nitrit dan nitrat, metode divalidasi terlebih dahulu. Hasil validasi metode analisis nitrit dan nitrat dengan pereaksi PABA/NEDA menunjukkan persentase perolehan kembali masing-masing antara 87,15–100,8% untuk nitrit dan 88,16–105,7% untuk nitrat. Setelah ditambah urea sebesar 0,66 g.kg-1 ke dalam tanah, konsentrasi nitrit dan nitrat pada semua sampel tanah mengalami peningkatan. Dari penelitian ini diketahui bahwa peningkatan kadar nitrit dan nitrat setelah ditambahkan urea sangat dipengaruhi oleh kondisi tanah.   ABSTRACT Nitrate and nitrite were sources of nitrogen for plants. Nitrogen is indispensable for the growth and development of plants. The forms of nitrogen in the environment undergoes a transformation as part of the nitrogen cycle like nitrification and denitrification. If nitrogen level in the soil is low, urea is used as a source of nitrogen. Changes of urea into nitrite or nitrate in some of soil samples need to be known. The levels of nitrite and nitrate are high can increase pollution in the soil. Some of soil samples which is used in this research were sandy soil, paddy soil

  6. Spectrophotometric determination of nitrite in soil and water using cefixime and central composite design

    Science.gov (United States)

    Shariati-Rad, Masoud; Irandoust, Mohsen; Mohammadi, Shabnam

    2015-10-01

    The present paper seeks to develop a simple method for the spectrophotometric determination of nitrite in soil and water samples and also measure optimum reaction conditions along with other analytical parameters. The method is based on the diazotization-coupling reaction of nitrite with cefixime and 1-naphthylamine in an acidic solution (Griess reaction). The final product that is an azo dye has an orange color with maximum absorption at 360 nm which Beer's Law is obeyed over the concentration range 0.02-15.00 mg L-1 of nitrite. Optimal conditions of the variables affecting the reaction were obtained by central composite design (CCD). A detection limit of 4.3 × 10-3 mg L-1 was obtained for determination of nitrite by the proposed method. The proposed method was successfully applied to determine nitrite in soil and water samples. The molar absorptivity of the product of the reaction and RSD in determination of nitrite in real samples are 4.1 × 103 (L mol-1 cm-1) and lower than 10%, respectively.

  7. Nitrate ammonification in mangrove soils: A hidden source of nitrite?

    NARCIS (Netherlands)

    Balk, Melike; Laverman, A.M.; Keuskamp, Joost A.; Laanbroek, Hendrikus J.

    2015-01-01

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought

  8. Differential contributions of ammonia oxidizers and nitrite oxidizers to nitrification in four paddy soils

    Science.gov (United States)

    Wang, Baozhan; Zhao, Jun; Guo, Zhiying; Ma, Jing; Xu, Hua; Jia, Zhongjun

    2015-01-01

    Rice paddy fields are characterized by regular flooding and nitrogen fertilization, but the functional importance of aerobic ammonia oxidizers and nitrite oxidizers under unique agricultural management is poorly understood. In this study, we report the differential contributions of ammonia-oxidizing archaea (AOA), bacteria (AOB) and nitrite-oxidizing bacteria (NOB) to nitrification in four paddy soils from different geographic regions (Zi-Yang (ZY), Jiang-Du (JD), Lei-Zhou (LZ) and Jia-Xing (JX)) that are representative of the rice ecosystems in China. In urea-amended microcosms, nitrification activity varied greatly with 11.9, 9.46, 3.03 and 1.43 μg NO3−-N g−1 dry weight of soil per day in the ZY, JD, LZ and JX soils, respectively, over the course of a 56-day incubation period. Real-time quantitative PCR of amoA genes and pyrosequencing of 16S rRNA genes revealed significant increases in the AOA population to various extents, suggesting that their relative contributions to ammonia oxidation activity decreased from ZY to JD to LZ. The opposite trend was observed for AOB, and the JX soil stimulated only the AOB populations. DNA-based stable-isotope probing further demonstrated that active AOA numerically outcompeted their bacterial counterparts by 37.0-, 10.5- and 1.91-fold in 13C-DNA from ZY, JD and LZ soils, respectively, whereas AOB, but not AOA, were labeled in the JX soil during active nitrification. NOB were labeled to a much greater extent than AOA and AOB, and the addition of acetylene completely abolished the assimilation of 13CO2 by nitrifying populations. Phylogenetic analysis suggested that archaeal ammonia oxidation was predominantly catalyzed by soil fosmid 29i4-related AOA within the soil group 1.1b lineage. Nitrosospira cluster 3-like AOB performed most bacterial ammonia oxidation in the ZY, LZ and JX soils, whereas the majority of the 13C-AOB in the JD soil was affiliated with the Nitrosomona communis lineage. The 13C-NOB was overwhelmingly

  9. Predicting the responses of soil nitrite-oxidizers to multi-factorial global change: a trait-based approach

    Directory of Open Access Journals (Sweden)

    Xavier eLE ROUX

    2016-05-01

    Full Text Available Soil microbial diversity is huge and a few grams of soil contain more bacterial taxa than there are bird species on Earth. This high diversity often makes predicting the responses of soil bacteria to environmental change intractable and restricts our capacity to predict the responses of soil functions to global change. Here, using a long-term field experiment in a California grassland, we studied the main and interactive effects of three global change factors (increased atmospheric CO2 concentration, precipitation and nitrogen addition, and all their factorial combinations, based on global change scenarios for central California on the potential activity, abundance and dominant taxa of soil nitrite-oxidizing bacteria (NOB. Using a trait-based model, we then tested whether categorizing NOB into a few functional groups unified by physiological traits enables understanding and predicting how soil NOB respond to global environmental change. Contrasted responses to global change treatments were observed between three main NOB functional types. In particular, putatively mixotrophic Nitrobacter, rare under most treatments, became dominant under the ‘High CO2+Nitrogen+Precipitation’ treatment. The mechanistic trait-based model, which simulated ecological niches of NOB types consistent with previous ecophysiological reports, helped predicting the observed effects of global change on NOB and elucidating the underlying biotic and abiotic controls. Our results are a starting point for representing the overwhelming diversity of soil bacteria by a few functional types that can be incorporated into models of terrestrial ecosystems and biogeochemical processes.

  10. Predicting the Responses of Soil Nitrite-Oxidizers to Multi-Factorial Global Change: A Trait-Based Approach.

    Science.gov (United States)

    Le Roux, Xavier; Bouskill, Nicholas J; Niboyet, Audrey; Barthes, Laure; Dijkstra, Paul; Field, Chris B; Hungate, Bruce A; Lerondelle, Catherine; Pommier, Thomas; Tang, Jinyun; Terada, Akihiko; Tourna, Maria; Poly, Franck

    2016-01-01

    Soil microbial diversity is huge and a few grams of soil contain more bacterial taxa than there are bird species on Earth. This high diversity often makes predicting the responses of soil bacteria to environmental change intractable and restricts our capacity to predict the responses of soil functions to global change. Here, using a long-term field experiment in a California grassland, we studied the main and interactive effects of three global change factors (increased atmospheric CO2 concentration, precipitation and nitrogen addition, and all their factorial combinations, based on global change scenarios for central California) on the potential activity, abundance and dominant taxa of soil nitrite-oxidizing bacteria (NOB). Using a trait-based model, we then tested whether categorizing NOB into a few functional groups unified by physiological traits enables understanding and predicting how soil NOB respond to global environmental change. Contrasted responses to global change treatments were observed between three main NOB functional types. In particular, putatively mixotrophic Nitrobacter, rare under most treatments, became dominant under the 'High CO2+Nitrogen+Precipitation' treatment. The mechanistic trait-based model, which simulated ecological niches of NOB types consistent with previous ecophysiological reports, helped predicting the observed effects of global change on NOB and elucidating the underlying biotic and abiotic controls. Our results are a starting point for representing the overwhelming diversity of soil bacteria by a few functional types that can be incorporated into models of terrestrial ecosystems and biogeochemical processes.

  11. Nitrification gene ratio and free ammonia explain nitrite and nitrous oxide production in urea-amended soils

    Science.gov (United States)

    Substantial efforts have been made to characterize soil nitrous oxide (N2O) emissions following N fertilizer addition. While nitrite (NO2-) is a central regulator of N2O production, NO2- and N2O responses to nitrogen (N) fertilizer amendments still cannot be readily predicted. Our objective was to...

  12. The acclimation of Chlorella to high-level nitrite for potential application in biological NOx removal from industrial flue gases.

    Science.gov (United States)

    Li, Tianpei; Xu, Gang; Rong, Junfeng; Chen, Hui; He, Chenliu; Giordano, Mario; Wang, Qiang

    2016-05-20

    Nitrogen oxides (NOx) are the components of fossil flue gas that give rise to the greatest environmental concerns. This study evaluated the ability of the green algae Chlorella to acclimate to high level of NOx and the potential utilization of Chlorella strains in biological NOx removal (DeNOx) from industrial flue gases. Fifteen Chlorella strains were subject to high-level of nitrite (HN, 176.5 mmolL(-1) nitrite) to simulate exposure to high NOx. These strains were subsequently divided into four groups with respect to their ability to tolerate nitrite (excellent, good, fair, and poor). One strain from each group was selected to evaluate their photosynthetic response to HN condition, and the nitrite adaptability of the four Chlorella strains were further identified by using chlorophyll fluorescence. The outcome of our experiments shows that, although high concentrations of nitrite overall negatively affect growth and photosynthesis of Chlorella strains, the degree of nitrite tolerance is a strain-specific feature. Some Chlorella strains have an appreciably higher ability to acclimate to high-level of nitrite. Acclimation is achieved through a three-step process of restrict, acclimate, and thriving. Notably, Chlorella sp. C2 was found to have a high tolerance and to rapidly acclimate to high concentrations of nitrite; it is therefore a promising candidate for microalgae-based biological NOx removal. Copyright © 2016 Elsevier GmbH. All rights reserved.

  13. Therapeutic Potential of the Nitrite-Generated NO Pathway in Vascular Dysfunction

    Science.gov (United States)

    Madigan, Michael; Zuckerbraun, Brian

    2013-01-01

    Nitric oxide (NO) generated through L-arginine metabolism by endothelial nitric oxide synthase (eNOS) is an important regulator of the vessel wall. Dysregulation of this system has been implicated in various pathological vascular conditions, including atherosclerosis, angiogenesis, arteriogenesis, neointimal hyperplasia, and pulmonary hypertension. The pathophysiology involves a decreased bioavailability of NO within the vessel wall by competitive utilization of L-arginine by arginase and “eNOS uncoupling.” Generation of NO through reduction of nitrate and nitrite represents an alternative pathway that may be utilized to increase the bioavailability of NO within the vessel wall. We review the therapeutic potential of the nitrate/nitrite/NO pathway in vascular dysfunction. PMID:23847616

  14. Absorption of atmospheric nitrogen dioxide by plants and soils. II. Nitrite accumulation, nitrite reductase activity and diurnal change of nitrogen dioxide absorption in leaves

    Energy Technology Data Exchange (ETDEWEB)

    Yoneyama, T.; Sasakawa, H.; Ishizuka, S.; Totsuka, T.

    1979-01-01

    NO/sub 2/ uptake by leaves and reduction systems of nitrite produced were investigated using 3-week-old kidney bean, sunflower, and corn plants, which were grown in vermiculite beds supplied with tap water. The plants were fumigated with ppM NO/sub 2/ for 6 hr in an artificially-lit chamber (30 klux), and the following things were observed. Fumigation in the light at daytime caused severe injury (wilting) in kidney bean leaves, and slight injury in sunflower leaves, but corn leaves were tolerant to this treatment. A high concentration of nitrite rapidly accumulted in the kidney bean leaves, but the nitrite reductase activity was only increased to a small extent. In sunflower leaves a high concentration of nitrite was accumulated, and the nitrite reductase activity also increased rapidly. Fumigation in the dark at nighttime caused low concentration of nitrite to accumulate in the kidney bean and sunflower leaves, and it was leveled down at the later fumigation time. The nitrite reductase activity of the two plants was increased with a slow rate continuously during the NO/sub 2/ fumigation period. On the other hand, in the corn leaves, nitrite was not detected in the daytime, but only a low concentration of nitrite was detected in the nighttime. A high activity of nitrite reductase was detected compared with the other two plants. Application of nitrite through the culture solution reduced nitrite accumulation in the light but not in the dark. These results indicate that acute NO/sub 2/ injury is mainly related to nitrite accumulation. Therefore, low NO/sub 2/ absorption and high nitrite reductase activity (including its rapid induction) may reduce injury in leaves. Absorption of /sup 15/NO/sub 2/ at night by sunflower leaves was around 14% that at daytime. These indicate that a diurnal change of NO/sub 2/ uptake is operating. 14 references, 2 figures, 3 tables.

  15. Nitrate reduction, nitrous oxide formation, and anaerobic ammonia oxidation to nitrite in the gut of soil-feeding termites (Cubitermes and Ophiotermes spp.)

    KAUST Repository

    Ngugi, David

    2011-11-28

    Soil-feeding termites play important roles in the dynamics of carbon and nitrogen in tropical soils. Through the mineralization of nitrogenous humus components, their intestinal tracts accumulate enormous amounts of ammonia, and nitrate and nitrite concentrations are several orders of magnitude above those in the ingested soil. Here, we studied the metabolism of nitrate in the different gut compartments of two Cubitermes and one Ophiotermes species using 15N isotope tracer analysis. Living termites emitted N 2 at rates ranging from 3.8 to 6.8nmolh -1 (g fresh wt.) -1. However, in homogenates of individual gut sections, denitrification was restricted to the posterior hindgut, whereas nitrate ammonification occurred in all gut compartments and was the prevailing process in the anterior gut. Potential rates of nitrate ammonification for the entire intestinal tract were tenfold higher than those of denitrification, implying that ammonification is the major sink for ingested nitrate in the intestinal tract of soil-feeding termites. Because nitrate is efficiently reduced already in the anterior gut, reductive processes in the posterior gut compartments must be fuelled by an endogenous source of oxidized nitrogen species. Quite unexpectedly, we observed an anaerobic oxidation of 15N-labelled ammonia to nitrite, especially in the P4 section, which is presumably driven by ferric iron; nitrification and anammox activities were not detected. Two of the termite species also emitted substantial amounts of N 2O, ranging from 0.4 to 3.9nmolh -1 (g fresh wt.) -1, providing direct evidence that soil-feeding termites are a hitherto unrecognized source of this greenhouse gas in tropical soils. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  16. Ammonium sorption and ammonia inhibition of nitrite-oxidizing bacteria explain contrasting soil N2O production

    Science.gov (United States)

    Venterea, R. T.; Sadowsky, M.; Breuillin-Sessoms, F.; Wang, P.; Clough, T. J.; Coulter, J. A.

    2015-12-01

    Better understanding of process controls over nitrous oxide (N2O) production in urine-impacted 'hot spots' and fertilizer bands is needed to improve mitigation strategies and emission models. Following amendment with bovine (Bos taurus) urine (Bu) or urea (Ur), we measured inorganic N, pH, N2O, and genes associated with nitrification in two soils ('L' and 'W') having similar texture, pH, C, and C/N ratio. Solution-phase ammonia (slNH3) was also calculated accounting for non-linear ammonium (NH4+) sorption capacities (ASC). Soil W displayed greater nitrification rates and nitrate (NO3-) levels than soil L, but was more resistant to nitrite (NO2-) accumulation and produced two to ten times less N2O than soil L. Genes associated with NO2- oxidation (nxrA) increased substantially in soil W but remained static in soil L. Soil NO2- was strongly correlated with N2O production, and cumulative (c-) slNH3 explained 87% of the variance in c-NO2-. Differences between soils were explained by greater slNH3 in soil L which inhibited NO2- oxidization leading to greater NO2- levels and N2O production. This is the first study to correlate the dynamics of soil slNH3, NO2-, N2O and nitrifier genes, and the first to show how ASC can regulate NO2- levels and N2O production.

  17. Cod liver oil in sodium nitrite induced hepatic injury: does it have a potential protective effect?

    Science.gov (United States)

    Sherif, I O; Al-Gayyar, M M

    2015-01-01

    Exposure to sodium nitrites, a food additive, at high levels has been reported to produce reactive nitrogen and oxygen species that cause dysregulation of inflammatory responses and tissue injury. In this work, we examined the impact of dietary cod liver oil on sodium nitrite-induced inflammation in rats. Thirty-two adult male Sprague-Dawely rats were treated with 80 mg/kg sodium nitrite in presence/absence of 5 ml/kg cod liver oil. Liver sections were stained with hematoxylin/eosin. We measured hepatic tumor necrosis factor (TNF)-α, interleukin-1 beta (IL)-1β, C-reactive protein (CRP), transforming growth factor (TGF)-β1, and caspase-3. Cod liver oil reduced sodium nitrite-induced hepatocyte damage. In addition, cod liver oil results in reduction of hepatic TNF-α, IL-1β, CRP, TGF-β1, and caspase-3 when compared with the sodium nitrite group. Cod liver oil ameliorates sodium nitrite-induced hepatic injury via multiple mechanisms including blocking sodium nitrite-induced elevation of inflammatory cytokines, fibrosis mediators, and apoptosis markers.

  18. Microbial sulphate reduction during anaerobic digestion: EGSB process performance and potential for nitrite suppression of SRB activity.

    Science.gov (United States)

    O'Reilly, C; Colleran, E

    2005-01-01

    The present study investigated mesophilic anaerobic treatment of sulphate-containing wastewater in EGSB reactors and assessed the inclusion of nitrite in the reactor influent as a method for control of biological sulphate reduction. Two EGSB reactors, R1 and R2, were operated for a period of 581 days at varying volumetric loading rates, COD/SO4(2-) ratios and influent nitrite concentrations (R2 only). COD removal efficiencies of > 93% were achieved in both reactors at influent sulphate concentrations of up to 3,000 mg l(-1). A two-fold increase in the influent sulphate concentration, giving an influent COD/SO4(2-) ratio of 2, resulted in a reduction in reactor COD removal efficiency to 84% and 89%, in R1 and R2, respectively. Despite inclusion of nitrite in the R2 influent at concentrations up to 500 mg NO2-N l(-1), sulphate reduction proceeded similarly in R2 and R1, suggesting the ineffectiveness of nitrite as a potential inhibitor of SRB

  19. Sodium nitrite potentiates renal oxidative stress and injury in hemoglobin exposed guinea pigs.

    Science.gov (United States)

    Baek, Jin Hyen; Zhang, Xiaoyuan; Williams, Matthew C; Hicks, Wayne; Buehler, Paul W; D'Agnillo, Felice

    2015-07-03

    Methemoglobin-forming drugs, such as sodium nitrite (NaNO2), may exacerbate oxidative toxicity under certain chronic or acute hemolytic settings. In this study, we evaluated markers of renal oxidative stress and injury in guinea pigs exposed to extracellular hemoglobin (Hb) followed by NaNO2 at doses sufficient to simulate clinically relevant acute methemoglobinemia. NaNO2 induced rapid and extensive oxidation of plasma Hb in this model. This was accompanied by increased renal expression of the oxidative response effectors nuclear factor erythroid 2-derived-factor 2 (Nrf-2) and heme oxygenase-1 (HO-1), elevated non-heme iron deposition, lipid peroxidation, interstitial inflammatory cell activation, increased expression of tubular injury markers kidney injury-1 marker (KIM-1) and liver-fatty acid binding protein (L-FABP), podocyte injury, and cell death. Importantly, these indicators of renal oxidative stress and injury were minimal or absent following infusion of Hb or NaNO2 alone. Together, these results suggest that the exposure to NaNO2 in settings associated with increased extracellular Hb may potentiate acute renal toxicity via processes that are independent of NaNO2 induced erythrocyte methemoglobinemia. Published by Elsevier Ireland Ltd.

  20. Potentially fatal new trend in performance enhancement: a cautionary note on nitrite

    Directory of Open Access Journals (Sweden)

    Naughton Declan P

    2010-06-01

    Full Text Available Abstract Background Considerable interest has been shown by athletes and scientists in the potential for nitric oxide and associated vasodilators to enhance performance. This study aims to explore potential misuse of vasodilators by the athletes, and to highlight the growing concern over these agents. Methods Retrospective analyses of anonymous inquiries recorded in the Drug Information Database™ (DID™ between January 2006 and June 2008 (inclusive. In this 30-month period, the DID™ recorded 198,023 inquiries, of which 118,724 were UK Licensed Pharmaceutical products with a further 79,299 inquiries made for substance not found in the database. Results Phosphodiesterase type 5 (PDE-5 inhibitors, dominated by Viagra®, ranked 16th among the substance groups. The proportion of the inquiries made regarding PDE-5 inhibitors, especially in comparison to antibiotics, painkillers or alcohol, appears to be above the level that would normally be expected from medical need. No significant change in the months leading up to the Beijing Olympics was observed. On the contrary, the Nitric/Nitrate group showed a notable increase between 2006-2007 and 2008, suggesting a potential increase in interest in using nitric oxide among athletes. Conclusions With patents recently filed for the use of agents containing sodium nitrite/nitrate to enhance blood flow for performance enhancement in sport, coupled with anecdotal evidence from internet athlete forums and media, there is a concern that athletes may endanger their health by using vasodilators to enhance athletic performance. PDE-5 inhibitors or chemicals in the nitrate/nitrate group are currently not prohibited or tested for by the doping control agencies but some are highly dangerous to health and can lead to cardiovascular collapse, coma and death. Its promotion among athletes as a performance enhancing supplement is ethically and medically questionable.

  1. Spatial interaction of archaeal ammonia-oxidizers and nitrite-oxidizing bacteria in an unfertilized grassland soil

    Directory of Open Access Journals (Sweden)

    Barbara eStempfhuber

    2016-01-01

    Full Text Available Interrelated successive transformation steps of nitrification are performed by distinct microbial groups – the ammonia-oxidizers, comprising ammonia-oxidizing archaea (AOA and bacteria (AOB, and nitrite-oxidizers such as Nitrobacter and Nitrospira, which are the dominant genera in the investigated soils. Hence, not only their presence and activity in the investigated habitat is required for nitrification, but also their temporal and spatial interactions. To demonstrate the interdependence of both groups and to address factors promoting putative niche differentiation within each group, temporal and spatial changes in nitrifying organisms were monitored in an unfertilized grassland site over an entire vegetation period at the plot scale of 10 m². Nitrifying organisms were assessed by measuring the abundance of marker genes (amoA for AOA and AOB, nxrA for Nitrobacter, 16S rRNA gene for Nitrospira selected for the respective sub-processes. A positive correlation between numerically dominant AOA and Nitrospira, and their co-occurrence at the same spatial scale in August and October, suggests that the nitrification process is predominantly performed by these groups and is restricted to a limited timeframe. Amongst nitrite-oxidizers, niche differentiation was evident in observed seasonally varying patterns of co-occurrence and spatial separation. While their distributions were most likely driven by substrate concentrations, oxygen availability may also have played a role under substrate-limited conditions. Phylogenetic analysis revealed temporal shifts in Nitrospira community composition with an increasing relative abundance of OTU03 assigned to sublineage V from August onwards, indicating its important role in nitrite oxidation.

  2. Soils - Potential Runoff

    Data.gov (United States)

    Kansas Data Access and Support Center — This digital spatial data set provides information on the spatial distribution of potential runoff-contributing areas in Kansas. Potential runoff-contributing areas...

  3. Peroxynitrite and NO+ donors form colored nitrite adducts with sinapinic acid: potential applications.

    Science.gov (United States)

    Akhter, Shirin; Green, James R; Root, Paul; Thatcher, Gregory J; Mutus, Bulent

    2003-06-01

    Sinapinic acid (3,5-dimethoxy-4-hydroxycinnamic acid, SA) reacted with peroxynitrous acid at neutral pH with a second-order rate constant of 812 M(-1)s(-1), to yield a red product (lambda(max), 532 nm). The identical colored product could be formed with acidified decomposed peroxynitrous acid solutions or nitrite at slower rates (0.1M HCl, 8.32 M(-1)s(-1); 10% acetic acid, 0.0004 M(-1)s(-1)). The red compound is thought to be O-nitrososinapinic acid (3,5-dimethoxy-4-nitrosooxycinnamic acid) which can be formed by reaction with either peroxynitrous acid or nitrous acid. The extinction coefficient of O-nitrososinapinic acid (ONSA) was estimated to be 8419 M(-1)cm(-1) at 510 nm in 10% acetic acid and 90% acetonitrile. ONSA was also formed via NO(+) transfer from S-nitrosoglutathione (GSNO). ONSA in turn can S-nitrosate low molecular weight thiols and protein thiols. SA was also shown to act as a peroxynitrite sink as it effectively prevented the oxidation of dihydrorhodamine under physiological conditions. The fact that O-nitrososinapinic acid is stable and can be used to S-nitrosate thiol containing amino acids, peptides, and proteins makes it a potentially useful reagent in the study of S-nitrosothiol biochemistry and physiology. In addition, the relatively high extinction coefficient of O-nitrososinapinic acid means that it could be utilized as an analyte for the spectroscopic detection of peroxynitrite or NO(+)-donors in the submicromolar range.

  4. Ethyl nitrite is produced in the human stomach from dietary nitrate and ethanol, releasing nitric oxide at physiological pH: potential impact on gastric motility.

    Science.gov (United States)

    Rocha, Bárbara S; Gago, Bruno; Barbosa, Rui M; Cavaleiro, Carlos; Laranjinha, João

    2015-05-01

    Nitric oxide ((∙)NO), a ubiquitous molecule involved in a plethora of signaling pathways, is produced from dietary nitrate in the gut through the so-called nitrate-nitrite-NO pathway. In the stomach, nitrite derived from dietary nitrate triggers a network of chemical reactions targeting endogenous and exogenous biomolecules, thereby producing new compounds with physiological activity. The aim of this study was to ascertain whether compounds with physiological relevance are produced in the stomach upon consumption of nitrate- and ethanol-rich foods. Human volunteers consumed a serving of lettuce (source of nitrate) and alcoholic beverages (source of ethanol). After 15 min, samples of the gastric headspace were collected and ethyl nitrite was identified by GC-MS. Wistar rats were used to study the impact of ethyl nitrite on gastric smooth muscle relaxation at physiological pH. Nitrogen oxides, produced from nitrite in the stomach, induce nitrosation of ethanol from alcoholic beverages in the human stomach yielding ethyl nitrite. Ethyl nitrite, a potent vasodilator, is produced in vivo upon the consumption of lettuce with either red wine or whisky. Moreover, at physiological pH, ethyl nitrite induces gastric smooth muscle relaxation through a cGMP-dependent pathway. Overall, these results suggest that ethyl nitrite is produced in the gastric lumen and releases (∙)NO at physiological pH, which ultimately may have an impact on gastric motility. Systemic effects may also be expected if ethyl nitrite diffuses through the gastric mucosa reaching blood vessels, therefore operating as a (∙)NO carrier throughout the body. These data pinpoint posttranslational modifications as an underappreciated mechanism for the production of novel molecules with physiological impact locally in the gut and highlight the notion that diet may fuel compounds with the potential to modulate gastrointestinal welfare. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Co-occurrence of nitrite-dependent anaerobic ammonium and methane oxidation processes in subtropical acidic forest soils.

    Science.gov (United States)

    Meng, Han; Wang, Yong-Feng; Chan, Ho-Wang; Wu, Ruo-Nan; Gu, Ji-Dong

    2016-09-01

    Anaerobic ammonium oxidation (anammox) and nitrite-dependent anaerobic methane oxidation (n-damo) are two new processes of recent discoveries linking the microbial nitrogen and carbon cycles. In this study, 16S ribosomal RNA (rRNA) gene of anammox bacteria and pmoA gene of n-damo bacteria were used to investigate their distribution and diversity in natural acidic and re-vegetated forest soils. The 16S rRNA gene sequences retrieved featured at least three species in two genera known anammox bacteria, namely Candidatus Brocadia anammoxidans, Candidatus Brocadia fulgida, and Candidatus Kuenenia stuttgartiensis while the pmoA gene amplified was affiliated with two species of known n-damo bacteria Candidatus Methylomirabilis oxyfera and a newly established Candidatus Methylomirabilis sp. According to the results, the diversity of anammox bacteria in natural forests was lower than in re-vegetated forests, but no significant difference was observed in n-damo community between them. Quantitative real-time PCR showed that both anammox and n-damo bacteria were more abundant in the lower layer (10-20 cm) than the surface layer (0-5 cm). The abundance of anammox bacteria varied from 2.21 × 10(5) to 3.90 × 10(6) gene copies per gram dry soil, and n-damo bacteria quantities were between 1.69 × 10(5) and 5.07 × 10(6) gene copies per gram dry soil in the two different layers. Both anammox and n-damo bacteria are reported for the first time to co-occur in acidic forest soil in this study, providing a more comprehensive information on more defined microbial processes contributing to C and N cycles in the ecosystems.

  6. Kinetic parameters and nitrate, nitrite changes in bioremediation of Toxic Pentaerythritol Tetranitrate (PETN) contaminated soil.

    Science.gov (United States)

    Sadani, Mohsen; Karami, Mohammad Amin; Teimouri, Fahimeh; Amin, Mohammad Mehdi; Moosavi, Seyed Mahdi; Dehdashti, Bahare

    2017-10-01

    Cleanup of areas contaminated by explosives is a public health concern. Some explosives can be carcinogenic in humans. Pentaerythritol Tetranitrate (PETN), a powerful explosive with very low water solubility, can be easily transported to ground waters. This study was conducted to determine the removal efficiencies of PETN from soil by bioremediation, and obtain kinetic parameters of biological process. This experimental study was conducted at the Environmental Health Engineering Lab (Isfahan University of Medical Sciences, Isfahan, Iran) in 2015-2016. In the present work, bioremediation of the explosive-polluted soils by PETN in anaerobic-aerobic landfarming method was performed. The influence of seeding and biosurfactant addition on bioremediation was also evaluated. The data were analyzed using Microsoft Excel software. The results show that, as the initial concentration of PETN increased, the lag phase was increased and the specific growth rate was increased up to 0.1/day in concentration of 50 mg/kg, and then it was decreased to 0.04/day. Subsequent decreases in specific growth rate can cause substrate inhibition. Seeding causes decrease in lag phase significantly. Biosurfactant addition had little to no impact on the length of lag phase, but biosurfactant plus seeding can increase the growth rate to 0.2/day, however, inhibitory effect of the initial concentration was started in very high concentration of PETN (150 mg/kg). Biosurfactant addition and seeding together have an impressive effect on biodegradation of PETN, furthermore seeding can enhance active microbial consortium and biosurfactant can improve the poor aqueous solubility of PETN, therefore making the substrate more accessible.

  7. Diisopropylammonium nitrite

    Directory of Open Access Journals (Sweden)

    Ying-Chun Wang

    2012-04-01

    Full Text Available In the title molecular salt, C6H16N+·NO2−, the cation forms two N—H...O hydrogen bonds to nearby nitrite anions which link the ionic units into chains propagating along the b-axis direction.

  8. Nitrite fixation by humic substances: Nitrogen-15 nuclear magnetic resonance evidence for potential intermediates in chemodenitrification

    Science.gov (United States)

    Thorn, K.A.; Mikita, M.A.

    2000-01-01

    Studies have suggested that NO2/-, produced during nitrification and denitrification, can become incorporated into soil organic matter and, in one of the processes associated with chemodenitrification, react with organic matter to form trace N gases, including N2O. To gain an understanding of the nitrosation chemistry on a molecular level, soil and aquatic humic substances were reacted with 15N-labeled NaNO2, and analyzed by liquid phase 15N and 13C nuclear magnetic resonance (NMR). The International Humic Substances Society (IHSS) Pahokee peat and peat humic acid were also reacted with Na15NO2 and analyzed by solid-state 15N NMR. In Suwannee River, Armadale, and Laurentian fulvic acids, phenolic rings and activated methylene groups underwent nitrosation to form nitrosophenols (quinone monoximes) and ketoximes, respectively. The oximes underwent Beckmann rearrangements to 2??amides, and Beckmann fragmentations to nitriles. The nitriles in turn underwent hydrolysis to 1??amides. Peaks tentatively identified as imine, indophenol, or azoxybenzene nitrogens were clearly present in spectra of samples nitrosated at pH 6 but diminished at pH 3. The 15N NMR spectrum of the peat humic acid exhibited peaks corresponding with N-nitroso groups in addition to nitrosophenols, ketoximes, and secondary Beckmann reaction products. Formation of N-nitroso groups was more significant in the whole peat compared with the peat humic acid. Carbon-13 NMR analyses also indicated the occurrence of nitrosative demethoxylation in peat and soil humic acids. Reaction of 15N-NH3 fixated fulvic acid with unlabeled NO2/- resulted in nitrosative deamination of aminohydroquinone N, suggesting a previously unrecognized pathway for production of N2 gas in soils fertilized with NH3.Studies have suggested that NO2-, produced during nitrification and denitrification, can become incorporated into soil organic matter and, in one of the processes associated with chemodenitrification, react with organic

  9. Nitric oxide formation from nitrite in zebrafish

    DEFF Research Database (Denmark)

    Jensen, Frank Bo

    2007-01-01

    Nitrite is a potential nitric oxide (NO) donor and may have important biological functions at low concentrations. The present study tests the hypothesis that nitrite accumulation across the gills in fish will cause a massive NO production from nitrite. Zebrafish were exposed to three different...

  10. Nitrous oxide reduction genetic potential from the microbial community of an intermittently aerated partial nitritation SBR treating mature landfill leachate.

    Science.gov (United States)

    Gabarró, J; Hernández-Del Amo, E; Gich, F; Ruscalleda, M; Balaguer, M D; Colprim, J

    2013-12-01

    This study investigates the microbial community dynamics in an intermittently aerated partial nitritation (PN) SBR treating landfill leachate, with emphasis to the nosZ encoding gene. PN was successfully achieved and high effluent stability and suitability for a later anammox reactor was ensured. Anoxic feedings allowed denitrifying activity in the reactor. The influent composition influenced the mixed liquor suspended solids concentration leading to variations of specific operational rates. The bacterial community was low diverse due to the stringent conditions in the reactor, and was mostly enriched by members of Betaproteobacteria and Bacteroidetes as determined by 16S rRNA sequencing from excised DGGE melting types. The qPCR analysis for nitrogen cycle-related enzymes (amoA, nirS, nirK and nosZ) demonstrated high amoA enrichment but being nirS the most relatively abundant gene. nosZ was also enriched from the seed sludge. Linear correlation was found mostly between nirS and the organic specific rates. Finally, Bacteroidetes sequenced in this study by 16S rRNA DGGE were not sequenced for nosZ DGGE, indicating that not all denitrifiers deal with complete denitrification. However, nosZ encoding gene bacteria was found during the whole experiment indicating the genetic potential to reduce N2O. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Predicting the Responses of Soil Nitrite-Oxidizers to Multi-Factorial Global Change: A Trait-Based Approach

    DEFF Research Database (Denmark)

    Le Roux, Xavier; Bouskill, Nicholas J.; Niboyet, Audrey

    2016-01-01

    Soil microbial diversity is huge and a few grams of soil contain more bacterial taxa than there are bird species on Earth. This high diversity often makes predicting the responses of soil bacteria to environmental change intractable and restricts our capacity to predict the responses of soil...

  12. Unraveling the potential of a combined nitritation-anammox biomass towards the biodegradation of pharmaceutically active compounds.

    Science.gov (United States)

    Kassotaki, Elissavet; Pijuan, Maite; Joss, Adriano; Borrego, Carles M; Rodriguez-Roda, Ignasi; Buttiglieri, Gianluigi

    2017-12-19

    In the past few years, anaerobic ammonium oxidation-based processes have attracted a lot of attention for their implementation at the mainstream line of wastewater treatment plants, due to the possibility of leading to energy autarky if combined with anaerobic digestion. However, little is known about the potential degradation of micropollutants by the microbial groups responsible of these processes and the few results available are inconclusive. This study aimed to assess the degradation capability of biomass withdrawn from a combined nitritation/anaerobic ammonium oxidation (combined N/A) pilot plant towards five pharmaceutically active compounds (ibuprofen, sulfamethoxazole, metoprolol, venlafaxine and carbamazepine). Batch experiments were performed under different conditions by selectively activating or inhibiting different microbial groups: i) regular combined N/A operation, ii) aerobic (optimal for nitrifying bacteria), iii) aerobic with allylthiourea (an inhibitor of ammonia monooxygenase, enzyme of ammonia oxidizing bacteria), iv) anoxic (optimal for anaerobic ammonium oxidizing bacteria), v) aerobic with acetate (optimal for heterotrophic bacteria) and vi) anoxic with acetate (optimal for heterotrophic denitrifying bacteria). Ibuprofen was the most biodegradable compound being significantly degraded (49-100%) under any condition except heterotrophic denitrification. Sulfamethoxazole, exhibited the highest removal (70%) under optimal conditions for nitrifying bacteria but in the rest of the experiments anoxic conditions were found to be slightly more favorable (up to 58%). For metoprolol the highest performance was obtained under anoxic conditions favoring anammox bacteria (62%). Finally, carbamazepine and venlafaxine were hardly removed (≤10% in the majority of cases). Taken together, these results suggest the specificity of different microbial groups that in combination with alternating operational parameters can lead to enhanced removal of some

  13. Potential Phosphorus Mobilisation in Peat Soils

    DEFF Research Database (Denmark)

    Forsmann, Ditte M.; Kjærgaard, Charlotte

    2012-01-01

    Re-establishment of wetlands on peat soils containing phosphorus bound to iron(III)-oxides can lead to an undesirable phosphorus loss to the aquatic environment due to the reductive dissolution of iron(III)-oxides. Thus it is important to be able to assess the potential phosphorus mobilisation from...... peat soils before a re-establishment takes place. The potential phosphorus mobilisation from a peat soil depends not only on the geochemical characteristics but also on the redox conditions, the hydrological regime in the area as well as the hydro-physical properties of the soil. The hypothesis....... Batch experiments were used to determine the potential phosphorus release for each location. The measured phosphorus release was related to the geochemical characteristic for the respective location. Furthermore, the potential phosphorus release was compared with the measured phosphorus mobilisation...

  14. Screening of fungi for soil remediation potential

    Science.gov (United States)

    Richard T. Lamar; Laura M. Main; Diane M. Dietrich; John A. Glaser

    1999-01-01

    The purpose of the present investigation was to determine if physiological and/or biochemical factors such as growth rate, tolerance to and ability to degrade PCP or creosote have use for predicting the potential bioremediation performance of fungi. Because we have focused the initial development of a fungal-based soil remediation technology on PCP- and/or creosote-...

  15. It is rocket science - why dietary nitrate is hard to 'beet'! Part II: further mechanisms and therapeutic potential of the nitrate-nitrite-NO pathway.

    Science.gov (United States)

    Mills, Charlotte Elizabeth; Khatri, Jibran; Maskell, Perry; Odongerel, Chimed; Webb, Andrew James

    2017-01-01

    Dietary nitrate (found in green leafy vegetables such as rocket and in beetroot) is now recognized to be an important source of nitric oxide, via the nitrate-nitrite-NO pathway. Dietary nitrate confers several cardiovascular beneficial effects on blood pressure, platelets, endothelial function, mitochondrial efficiency and exercise. Having described key twists and turns in the elucidation of the pathway and the underlying mechanisms in Part I, we explore the more recent developments which have served to confirm mechanisms, extend our understanding, and discover new properties and potential therapeutic uses of the pathway in Part II. Even the established dependency on low oxygen states for bioactivation of nitrite has recently been challenged. Dietary nitrate appears to be an important component of 'healthy diets', such as the DASH diet to lower blood pressure and the Mediterranean diet, with its potential to lower cardiovascular risk, possibly through beneficial interactions with a range of other constituents. The World Cancer Research Foundation report strong evidence for vegetables including spinach and lettuce (high nitrate-containing) decreasing cancer risk (mouth, pharynx, larynx, oesophagus and stomach), summarized in a 'Nitrate-Cancer Risk Veg-Table'. The European Space Agency recommends that beetroot, lettuce, spinach and rocket (high-nitrate vegetables) are grown to provide food for long-term space missions. Nitrate, an ancient component of rocket fuel, could support sustainable crops for healthy humans. © 2016 The British Pharmacological Society.

  16. 21 CFR 181.34 - Sodium nitrite and potassium nitrite.

    Science.gov (United States)

    2010-04-01

    ... fixatives and preservative agents, with or without sodium or potassium nitrate, in the curing of red meat... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrite and potassium nitrite. 181.34...-Sanctioned Food Ingredients § 181.34 Sodium nitrite and potassium nitrite. Sodium nitrite and potassium...

  17. Evaluating operation strategies and process stability of a single stage nitritation-anammox SBR by use of the oxidation-reduction potential (ORP).

    Science.gov (United States)

    Lackner, Susanne; Horn, Harald

    2012-03-01

    A single stage nitritation-anammox SBR was operated for 300 days to investigate the impact of cycle operation strategies on process performance and the oxidation-reduction potential (ORP) as process monitoring parameter. Different combinations of feeding (interval, continuous, one-time) and aeration (interval, continuous) strategies were tested revealing that interval feeding and interval aeration was the most suitable case in terms of process performance (ammonium removal, nitrate production and pH stability) and use of the ORP value as indicator parameter. Further investigations into the use of the ORP value showed clear correlations of the ORP slope with the air flow rate and the maximum ORP peak with the ammonium loading under varying operation conditions. Depletion of the main substrates (ammonium and oxygen) was also detectable fastest following the ORP value proofing its worth for process control. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Nutritive potential of some 'edible' soils in Blantyre city, Malawi ...

    African Journals Online (AJOL)

    Background Pregnant women in Malawi consume soil, but the nutritive potential of these soils is uncertain. Methods We collected 'edible' Malawian soil samples from Ndirande, Mpingwe and Soche hills and bought an Indian soil sample from a shop in Limbe and tested them for iron, calcium, zinc, magnesium, lead, pH, ...

  19. Time-dependent depletion of nitrite in pork/beef and chicken meat products and its effect on nitrite intake estimation

    OpenAIRE

    Merino, Leonardo; Darnerudc, Per Ola; Toldrá Vilardell, Fidel; Ilbäckc, Nils Gunnar

    2016-01-01

    ABSTRACT The food additive nitrite (E249, E250) is commonly used in meat curing as a food preservation method. Because of potential negative health effects of nitrite, its use is strictly regulated. In an earlier study we have shown that the calculated intake of nitrite in children can exceed the acceptable daily intake (ADI) when conversion from dietary nitrate to nitrite is included. This study examined time-dependent changes in nitrite levels in four Swedish meat products frequently eaten ...

  20. Nitrates and nitrites intoxications’ management

    Directory of Open Access Journals (Sweden)

    Alexandra Trif

    2007-12-01

    Full Text Available The study pointed out the major sources for clinical and subclinical intoxications with nitrates/nitrites (drinking water and nitrates containing fertilizers, circumstances that determine fertilizers to became sources of intoxication (excessive fertilization/consecutive high level of nitrates in fodders, free access of animals to the fertilizers, administration into the diet instead of natrium chloride, factors that determine high nitrates accumulation in fodders despite optimal fertilization (factors related to the plants, soil, clime, harvest methods, storage, agrotechnical measures, nitrates/nitrites toxicity (over 45 ppm nitrates in drinking water, over 0.5 g nitrate/100 g D.M fodder/diet, the factors that influence nitrates/nitrites toxicity ( species, age, rate of feeding, diet balance especially energetically, pathological effects and symptoms (irritation and congestions on digestive tract, resulting diarrhoea, transformation of hemoglobin into methemoglobin determining severe respiratory insufficiency, vascular collapse, low blood pressure inthe acute nitrates intoxication; hypotiroidism, hypovitaminosis A, reproductive disturbances(abortion, low rate of fertility, dead born offspring, diarrhoea and/or respiratory insufficiency in new born e.g. calves, immunosuppression, decrease of milk production in chronic intoxication. There were presented some suggestions concerning management practices to limit nitrate intoxication (analyze of nitrates/nitrites in water and fodders, good management of the situation of risk ,e .g. dilution of the diet with low nitrate content fodders, feeding with balanced diet in energy, protein, minerals and vitamins, accommodation to high nitrate level diet, avoid grazing one week after a frost period, avoid feeding chop green fodders stored a couple of days, monitoring of health status of animals fed with fodders containing nitrates at risk level, a.o..

  1. Bioprospecting potential of the soil metagenome: novel enzymes and bioactivities.

    Science.gov (United States)

    Lee, Myung Hwan; Lee, Seon-Woo

    2013-09-01

    The microbial diversity in soil ecosystems is higher than in any other microbial ecosystem. The majority of soil microorganisms has not been characterized, because the dominant members have not been readily culturable on standard cultivation media; therefore, the soil ecosystem is a great reservoir for the discovery of novel microbial enzymes and bioactivities. The soil metagenome, the collective microbial genome, could be cloned and sequenced directly from soils to search for novel microbial resources. This review summarizes the microbial diversity in soils and the efforts to search for microbial resources from the soil metagenome, with more emphasis on the potential of bioprospecting metagenomics and recent discoveries.

  2. Bioprospecting Potential of the Soil Metagenome: Novel Enzymes and Bioactivities

    Directory of Open Access Journals (Sweden)

    Myung Hwan Lee

    2013-09-01

    Full Text Available The microbial diversity in soil ecosystems is higher than in any other microbial ecosystem. The majority of soil microorganisms has not been characterized, because the dominant members have not been readily culturable on standard cultivation media; therefore, the soil ecosystem is a great reservoir for the discovery of novel microbial enzymes and bioactivities. The soil metagenome, the collective microbial genome, could be cloned and sequenced directly from soils to search for novel microbial resources. This review summarizes the microbial diversity in soils and the efforts to search for microbial resources from the soil metagenome, with more emphasis on the potential of bioprospecting metagenomics and recent discoveries.

  3. Soil HONO Emissions and Its Potential Impact on the Atmospheric Chemistry and Nitrogen Cycle

    Science.gov (United States)

    Su, H.; Chen, C.; Zhang, Q.; Poeschl, U.; Cheng, Y.

    2014-12-01

    Hydroxyl radicals (OH) are a key species in atmospheric photochemistry. In the lower atmosphere, up to ~30% of the primary OH radical production is attributed to the photolysis of nitrous acid (HONO), and field observations suggest a large missing source of HONO. The dominant sources of N(III) in soil, however, are biological nitrification and denitrification processes, which produce nitrite ions from ammonium (by nitrifying microbes) as well as from nitrate (by denitrifying microbes). We show that soil nitrite can release HONO and explain the reported strength and diurnal variation of the missing source. The HONO emissions rates are estimated to be comparable to that of nitric oxide (NO) and could be an important source of atmospheric reactive nitrogen. Fertilized soils appear to be particularly strong sources of HONO. Thus, agricultural activities and land-use changes may strongly influence the oxidizing capacity of the atmosphere. A new HONO-DNDC model was developed to simulate the evolution of HONO emissions in agriculture ecosystems. Because of the widespread occurrence of nitrite-producing microbes and increasing N and acid deposition, the release of HONO from soil may also be important in natural environments, including forests and boreal regions. Reference: Su, H. et al., Soil Nitrite as a Source of Atmospheric HONO and OH Radicals, Science, 333, 1616-1618, 10.1126/science.1207687, 2011.

  4. Potential for Increasing Soil Nutrient Availability via Soil Organic Matter Improvement Using Pseudo Panel Data

    NARCIS (Netherlands)

    Chavez Clemente, M.D.; Berentsen, P.B.M.; Oenema, O.; Oude Lansink, A.G.J.M.

    2014-01-01

    Fixed and random effect models were applied to a pseudo-panel data built of soil analysis reports from tobacco farms to analyze relationships between soil characteristics like soil organic matter (SOM) and soil nitrogen (N), phosphorous (P) and potassium (K) and to explore the potential for

  5. Lead, Zinc and Nitrite Levels of Staple Crop Cultivars in Ameka and ...

    African Journals Online (AJOL)

    BSN

    Nitrite is present naturally in soils, meats, plants and drinking water. However, under unfavorable conditions, nitrite may enter the food chain via microbial reduction of nitrate thereby endangering human health (Sebecic and Vedrina, 1998). Nitrate may be reduced to nitrite when cooking is carried out in aluminum utensils.

  6. Transformers as a potential for soil contamination

    Directory of Open Access Journals (Sweden)

    N. Stojić

    2014-10-01

    Full Text Available The aim of this paper is to investigate the presence of PCBs and heavy metals in the surrounding soil and also in the soil of the receiving pit located below the PCB contaminated transformer. Concentrations of PCBs in our samples are ranged from 0,308 to 0,872 mg/kg of absolutely dry soil.

  7. Global distribution of soil phosphorus retention potential

    NARCIS (Netherlands)

    Batjes, N.H.

    2011-01-01

    Limited availability of P in soils to crops may be due to deficiency and/or severe P retention. Earlier studies that drew on large soil profile databases have indicated that it is not (yet) feasible to present meaningful values for “plant-available” soil P, obtained according to comparable

  8. Nitrite in feed: From Animal health to human health

    Energy Technology Data Exchange (ETDEWEB)

    Cockburn, Andrew [Institute for Research on Environment and Sustainability, Devonshire Building, University of Newcastle upon Tyne, Newcastle upon Tyne, NE17RU (United Kingdom); Brambilla, Gianfranco [Istituto Superiore di Sanità, Toxicological chemistry unit, Viale Regina Elena 299, 00161 Rome (Italy); Fernández, Maria-Luisa [Departamento de Medio Ambiente, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Ministerio de Ciencia e Innovación, Carretera de la Coruña, 28040 Madrid (Spain); Arcella, Davide [Unit on Data Collection and Exposure, European Food Safety Authority, Largo N. Palli 5/A43100 Parma (Italy); Bordajandi, Luisa R. [Unit on Contaminants in the Food chain, European Food Safety Authority, Largo N. Palli 5/A, 43100 Parma (Italy); Cottrill, Bruce [Policy Delivery Group, Animal Health and Welfare, ADAS, Wolverhampton (United Kingdom); Peteghem, Carlos van [University of Gent, Harelbekestraat 72, 9000 Gent (Belgium); Dorne, Jean-Lou, E-mail: jean-lou.dorne@efsa.europa.eu [Unit on Contaminants in the Food chain, European Food Safety Authority, Largo N. Palli 5/A, 43100 Parma (Italy)

    2013-08-01

    Nitrite is widely consumed from the diet by animals and humans. However the largest contribution to exposure results from the in vivo conversion of exogenously derived nitrate to nitrite. Because of its potential to cause to methaemoglobin (MetHb) formation at excessive levels of intake, nitrite is regulated in feed and water as an undesirable substance. Forages and contaminated water have been shown to contain high levels of nitrate and represent the largest contributor to nitrite exposure for food-producing animals. Interspecies differences in sensitivity to nitrite intoxication principally result from physiological and anatomical differences in nitrite handling. In the case of livestock both pigs and cattle are relatively susceptible. With pigs this is due to a combination of low levels of bacterial nitrite reductase and hence potential to reduce nitrite to ammonia as well as reduced capacity to detoxify MetHb back to haemoglobin (Hb) due to intrinsically low levels of MetHb reductase. In cattle the sensitivity is due to the potential for high dietary intake and high levels of rumen conversion of nitrate to nitrite, and an adaptable gut flora which at normal loadings shunts nitrite to ammonia for biosynthesis. However when this escape mechanism gets overloaded, nitrite builds up and can enter the blood stream resulting in methemoglobinemia. Looking at livestock case histories reported in the literature no-observed-effect levels of 3.3 mg/kg body weight (b.w.) per day for nitrite in pigs and cattle were estimated and related to the total daily nitrite intake that would result from complete feed at the EU maximum permissible level. This resulted in margins of safety of 9-fold and 5-fold for pigs and cattle, respectively. Recognising that the bulkiness of animal feed limits their consumption, these margins in conjunction with good agricultural practise were considered satisfactory for the protection of livestock health. A human health risk assessment was also

  9. Nitrite in feed: from animal health to human health.

    Science.gov (United States)

    Cockburn, Andrew; Brambilla, Gianfranco; Fernández, Maria-Luisa; Arcella, Davide; Bordajandi, Luisa R; Cottrill, Bruce; van Peteghem, Carlos; Dorne, Jean-Lou

    2013-08-01

    Nitrite is widely consumed from the diet by animals and humans. However the largest contribution to exposure results from the in vivo conversion of exogenously derived nitrate to nitrite. Because of its potential to cause to methaemoglobin (MetHb) formation at excessive levels of intake, nitrite is regulated in feed and water as an undesirable substance. Forages and contaminated water have been shown to contain high levels of nitrate and represent the largest contributor to nitrite exposure for food-producing animals. Interspecies differences in sensitivity to nitrite intoxication principally result from physiological and anatomical differences in nitrite handling. In the case of livestock both pigs and cattle are relatively susceptible. With pigs this is due to a combination of low levels of bacterial nitrite reductase and hence potential to reduce nitrite to ammonia as well as reduced capacity to detoxify MetHb back to haemoglobin (Hb) due to intrinsically low levels of MetHb reductase. In cattle the sensitivity is due to the potential for high dietary intake and high levels of rumen conversion of nitrate to nitrite, and an adaptable gut flora which at normal loadings shunts nitrite to ammonia for biosynthesis. However when this escape mechanism gets overloaded, nitrite builds up and can enter the blood stream resulting in methemoglobinemia. Looking at livestock case histories reported in the literature no-observed-effect levels of 3.3mg/kg body weight (b.w.) per day for nitrite in pigs and cattle were estimated and related to the total daily nitrite intake that would result from complete feed at the EU maximum permissible level. This resulted in margins of safety of 9-fold and 5-fold for pigs and cattle, respectively. Recognising that the bulkiness of animal feed limits their consumption, these margins in conjunction with good agricultural practise were considered satisfactory for the protection of livestock health. A human health risk assessment was also

  10. Soil CO2 Dynamics in a Tree Island Soil of the Pantanal: The Role of Soil Water Potential

    Science.gov (United States)

    Johnson, Mark S.; Couto, Eduardo Guimarães; Pinto Jr, Osvaldo B.; Milesi, Juliana; Santos Amorim, Ricardo S.; Messias, Indira A. M.; Biudes, Marcelo Sacardi

    2013-01-01

    The Pantanal is a biodiversity hotspot comprised of a mosaic of landforms that differ in vegetative assemblages and flooding dynamics. Tree islands provide refuge for terrestrial fauna during the flooding period and are particularly important to the regional ecosystem structure. Little soil CO2 research has been conducted in this region. We evaluated soil CO2 dynamics in relation to primary controlling environmental parameters (soil temperature and soil water). Soil respiration was computed using the gradient method using in situ infrared gas analyzers to directly measure CO2 concentration within the soil profile. Due to the cost of the sensors and associated equipment, this study was unreplicated. Rather, we focus on the temporal relationships between soil CO2 efflux and related environmental parameters. Soil CO2 efflux during the study averaged 3.53 µmol CO2 m−2 s−1, and was equivalent to an annual soil respiration of 1220 g C m−2 y−1. This efflux value, integrated over a year, is comparable to soil C stocks for 0–20 cm. Soil water potential was the measured parameter most strongly associated with soil CO2 concentrations, with high CO2 values observed only once soil water potential at the 10 cm depth approached zero. This relationship was exhibited across a spectrum of timescales and was found to be significant at a daily timescale across all seasons using conditional nonparametric spectral Granger causality analysis. Hydrology plays a significant role in controlling CO2 efflux from the tree island soil, with soil CO2 dynamics differing by wetting mechanism. During the wet-up period, direct precipitation infiltrates soil from above and results in pulses of CO2 efflux from soil. The annual flood arrives later, and saturates soil from below. While CO2 concentrations in soil grew very high under both wetting mechanisms, the change in soil CO2 efflux was only significant when soils were wet from above. PMID:23762259

  11. Modelling soil organic carbon in Danish agricultural soils suggests low potential for future carbon sequestration

    DEFF Research Database (Denmark)

    Taghizadeh-Toosi, Arezoo; Olesen, Jørgen Eivind

    2016-01-01

    Soil organic carbon (SOC) is in active exchange with the atmosphere. The amount of organic carbon (OC) input into the soil and SOC turnover rate are important for predicting the carbon (C) sequestration potential of soils subject to changes in land-use and climate. The C-TOOL model was developed...

  12. Performance evaluation of TDT soil water content and watermark soil water potential sensors

    Science.gov (United States)

    This study evaluated the performance of digitized Time Domain Transmissometry (TDT) soil water content sensors (Acclima, Inc., Meridian, ID) and resistance-based soil water potential sensors (Watermark 200, Irrometer Company, Inc., Riverside, CA) in two soils. The evaluation was performed by compar...

  13. Potentials for Soil Enzyme as Indicators of Ecological Management

    Science.gov (United States)

    Senwo, Z. N.; Manu, A.; Coleman, T. L.

    1997-01-01

    Activity measurements of selected soil enzymes (cellulase, glucosidase, amidohydrolase, phosphatase, arylsulfatase) involved in carbon, nitrogen, phosphorus, and sulfur cycling in the biosphere, hold potential as early and sensitive indicators of soil ecological stress and restoration, These measurements are advantageous because the procedures are simple, rapid, and reproducible over time. Enzyme activities are sensitive to short-term changes in soil and kind-use management. Enzyme activities have also been observed to be closely related to soil organic matter proposed as an index of soil quality.

  14. Carbon sequestration potential of soils in southeast Germany derived from stable soil organic carbon saturation.

    Science.gov (United States)

    Wiesmeier, Martin; Hübner, Rico; Spörlein, Peter; Geuß, Uwe; Hangen, Edzard; Reischl, Arthur; Schilling, Bernd; von Lützow, Margit; Kögel-Knabner, Ingrid

    2014-02-01

    Sequestration of atmospheric carbon (C) in soils through improved management of forest and agricultural land is considered to have high potential for global CO2 mitigation. However, the potential of soils to sequester soil organic carbon (SOC) in a stable form, which is limited by the stabilization of SOC against microbial mineralization, is largely unknown. In this study, we estimated the C sequestration potential of soils in southeast Germany by calculating the potential SOC saturation of silt and clay particles according to Hassink [Plant and Soil 191 (1997) 77] on the basis of 516 soil profiles. The determination of the current SOC content of silt and clay fractions for major soil units and land uses allowed an estimation of the C saturation deficit corresponding to the long-term C sequestration potential. The results showed that cropland soils have a low level of C saturation of around 50% and could store considerable amounts of additional SOC. A relatively high C sequestration potential was also determined for grassland soils. In contrast, forest soils had a low C sequestration potential as they were almost C saturated. A high proportion of sites with a high degree of apparent oversaturation revealed that in acidic, coarse-textured soils the relation to silt and clay is not suitable to estimate the stable C saturation. A strong correlation of the C saturation deficit with temperature and precipitation allowed a spatial estimation of the C sequestration potential for Bavaria. In total, about 395 Mt CO2 -equivalents could theoretically be stored in A horizons of cultivated soils - four times the annual emission of greenhouse gases in Bavaria. Although achieving the entire estimated C storage capacity is unrealistic, improved management of cultivated land could contribute significantly to CO2 mitigation. Moreover, increasing SOC stocks have additional benefits with respect to enhanced soil fertility and agricultural productivity. © 2013 John Wiley & Sons Ltd.

  15. Remote sensing as a tool for estimating soil erosion potential

    Science.gov (United States)

    Morris-Jones, D. R.; Morgan, K. M.; Kiefer, R. W.

    1979-01-01

    The Universal Soil Loss Equation is a frequently used methodology for estimating soil erosion potential. The Universal Soil Loss Equation requires a variety of types of geographic information (e.g. topographic slope, soil erodibility, land use, crop type, and soil conservation practice) in order to function. This information is traditionally gathered from topographic maps, soil surveys, field surveys, and interviews with farmers. Remote sensing data sources and interpretation techniques provide an alternative method for collecting information regarding land use, crop type, and soil conservation practice. Airphoto interpretation techniques and medium altitude, multi-date color and color infrared positive transparencies (70mm) were utilized in this study to determine their effectiveness for gathering the desired land use/land cover data. Successful results were obtained within the test site, a 6136 hectare watershed in Dane County, Wisconsin.

  16. Field-Scale Pattern of Denitrifying Microorganisms and N2O Emission Rates Indicate a High Potential for Complete Denitrification in an Agriculturally Used Organic Soil.

    Science.gov (United States)

    Schulz, Stefanie; Kölbl, Angelika; Ebli, Martin; Buegger, Franz; Schloter, Michael; Fiedler, Sabine

    2017-11-01

    More than 50% of all anthropogenic N2O emissions come from the soil. Drained Histosols that are used for agricultural purposes are particularly potent sources of denitrification due to higher stocks of organic matter and fertiliser application. However, conditions that favour denitrification can vary considerably across a field and change significantly throughout the year. Spatial and temporal denitrifier dynamics were assessed in a drained, intensely managed Histosol by focusing on the genetic nitrite and N2O reduction potential derived from the abundance of nirK, nirS and nosZ genes. These data were correlated with soil properties at two different points in time in 2013. N2O emissions were measured every 2 weeks over three vegetation periods (2012-2014). Very low N2O emission rates were measured throughout the entire period of investigation in accordance with the geostatistical data that revealed an abundance of microbes carrying the N2O reductase gene nosZ. This, along with neutral soil pH values, is indicative of high microbial denitrification potential. While the distribution of the microbial communities was strongly influenced by total organic carbon and nitrogen pools in March, the spatial distribution pattern was not related to the distribution of soil properties in October, when higher nutrient availability was observed. Different nitrite reducer groups prevailed in spring and autumn. While nirS, followed by nosZ and nirK, was most abundant in March, the latter was the dominant nitrite reductase in October.

  17. Potentials and management of nutrient status of soils of Ikwuano ...

    African Journals Online (AJOL)

    The study was carried out to evaluate the nutrient status of the nine farming zones of Ikwuano local government Area of Abia State, to quantify in relation to their cassava crop production potentials. Free survey method was applied in a reconnaissance soil survey to collect soil samples at 0-30cm depth. Nine samples were ...

  18. Investigation Of The Microbial-Induced Corrosion Potential Of Soils ...

    African Journals Online (AJOL)

    Investigation of sulphate-reducing bacteria induced corrosion potential of soils along 18-inch 45km Tebidaba/Brass underground oil pipeline in Southern Ijaw LGA of Bayelsa State, Nigeria, is carried out experimentally. The analysis involves determination of some physico-chemical parameters of soils in the pipeline route, ...

  19. Magnesium Releasinng Potential of soils of Edo State, Nigeria ...

    African Journals Online (AJOL)

    A green house experiment was conducted to determine the magnesium releasing potential of soil of Edo State. Exhaustive cropping technique was used with maize as test crop. Twenty composite surface soil samples collected from pre-classified sites were used for this study. From the study, exchangeable Mg decreased ...

  20. Comparison of soil water potential sensors: a drying experiment

    NARCIS (Netherlands)

    Degre, Aurore; Ploeg, van der M.J.; Caldwell, Todd; Gooren, H.P.A.

    2017-01-01

    The soil water retention curve (WRC) plays a major role in a soil’s hydrodynamic behavior. Many measurement techniques are currently available for determining the WRC in the laboratory. Direct in situ WRC can be obtained from simultaneous soil moisture and water potential readings covering a wide

  1. Soil water potential requirement for germination of winter wheat

    Science.gov (United States)

    In semi-arid climates seed is often sown into soil with inadequate water for rapid germination. This study was designed to measure the soil water potential limits for rapid, adequate, and marginal germination of winter wheat (Triticum aestivum L.). We also tested for differences between cultivars an...

  2. Predicting Potential C Mineralization of Tundra Soils Using Spectroscopy Techniques

    Science.gov (United States)

    The large amounts of organic matter stored in permafrost-region soils are preserved in a relatively undecomposed state by the cold and wet environmental conditions limiting decomposer activity. With pending climate changes and the potential for warming of Arctic soils, there is a need to better unde...

  3. Downward Movement of Potentially Toxic Elements in Biosolids Amended Soils

    Directory of Open Access Journals (Sweden)

    Silvana Irene Torri

    2012-01-01

    Full Text Available Potentially toxic elements (PTEs in soils are mainly associated with the solid phase, bound to the surface of solid components, or precipitated as minerals. For most PTEs, only a small portion is dissolved in the soil solution. However, there is an interest in following the fate of mobile PTEs in the environment, for a growing amount of evidence indicates that downward movement of PTEs may occur in biosolids amended soils, leading to groundwater contamination. Therefore, it is crucial to understand the factors that control the release of these elements after land application of biosolids, in order to overcome problems related to downward movement of PTEs in the soil profile.

  4. The dissolved organic matter as a potential soil quality indicator in arable soils of Hungary.

    Science.gov (United States)

    Filep, Tibor; Draskovits, Eszter; Szabó, József; Koós, Sándor; László, Péter; Szalai, Zoltán

    2015-07-01

    Although several authors have suggested that the labile fraction of soils could be a potential soil quality indicator, the possibilities and limitations of using the dissolved organic matter (DOM) fraction for this purpose have not yet been investigated. The objective of this study was to evaluate the hypothesis that DOM is an adequate indicator of soil quality. To test this, the soil quality indices (SQI) of 190 arable soils from a Hungarian dataset were estimated, and these values were compared to DOM parameters (DOC and SUVA254). A clear difference in soil quality was found between the soil types, with low soil quality for arenosols (average SQI 0.5) and significantly higher values for gleysols, vertisols, regosols, solonetzes and chernozems. The SQI-DOC relationship could be described by non-linear regression, while a linear connection was observed between SQI and SUVA. The regression equations obtained for the dataset showed only one relatively weak significant correlation between the variables, for DOC (R (2) = 0.157(***); n = 190), while non-significant relationships were found for the DOC and SUVA254 values. However, an envelope curve operated with the datasets showed the robust potential of DOC to indicate soil quality changes, with a high R (2) value for the envelope curve regression equation. The limitations to using the DOM fraction of soils as a quality indicator are due to the contradictory processes which take place in soils in many cases.

  5. Combating land degradation: the potential of soil reconversion

    Science.gov (United States)

    Tobias, Silvia; Conen, Franz; Duss, Adrian; Wenzel, Leonore; Buser, Christine; Alewell, Christine

    2017-04-01

    Land degradation is usually not seen as a major problem in industrialised countries, although continuous soil sealing for human settlements and infrastructure entails the loss of agricultural land, landscape fragmentation and the loss of natural habitats. In many European countries, land-take on greenfields is unbowed, while, at the same time, there is a considerable number of unused brownfields, like abandoned rail yards and industrial or military sites. In addition, many new by-pass roads have been constructed to take up the volume of traffic and unburden the towns and villages from traffic emissions, but the old roads are rarely downgraded or reconverted and risk being used as shortcuts. Today the sealed area exceeds the requirements of the current generation and contributes to degraded land with heavily disturbed soil-borne ecosystem services. Soil reconversion, i.e. replacing a sealed surface with soil to restore ecosystem services, could mitigate this unsustainable trend that restricts the options of future generations. This contribution discusses the potential and challenges of soil reconversion to reduce net soil loss. The expanses of brownfield area vary between countries, whereas the rate of new soil sealing is still high in most countries and soil reconversion should be considered more. Our research revealed that the current techniques enable successful restoration of agricultural soils and pioneer habitats on site. However, reconverting single small areas can hardly mitigate landscape fragmentation at a regional scale. The same principle prevails as for soil sealing, but in the inverse way: the benefit of soil reconversion may appear small for single cases, but in the sum soil reconversion might be effective. Today, many brownfield areas stay sealed because of economic and political reasons, or because the potential benefit from restoring ecosystem services at these brownfield sites is not known. We developed a mapping approach to assess the potential

  6. Soil organic carbon sequestration potential of conservation vs. conventional tillage

    Science.gov (United States)

    Meurer, Katharina H. E.; Ghafoor, Abdul; Haddaway, Neal R.; Bolinder, Martin A.; Kätterer, Thomas

    2017-04-01

    Soil tillage has been associated with many negative impacts on soil quality, especially a reduction in soil organic carbon (SOC). The benefits of no tillage (NT) on topsoil SOC concentrations have been demonstrated in several reviews, but the effect of reduced tillage (RT) compared to conventional tillage (CT) that usually involves soil inversion through moldboard ploughing is still unclear. Moreover, the effect of tillage on total SOC stocks including deeper layers is still a matter of considerable debate, because the assessment depends on many factors such as depth and method of measurement, cropping systems, soil type, climatic conditions, and length of the experiments used for the analysis. From a recently published systematic map database consisting of 735 long-term field experiments (≥ 10 years) within the boreal and temperate climate zones (Haddaway et al. 2015; Environmental Evidence 4:23), we selected all tillage studies (about 80) reporting SOC concentrations along with dry soil bulk density and conducted a systematic review. SOC stocks were calculated considering both fixed soil depths and by using the concept of equivalent soil mass. A meta-analysis was used to determine the influence of environmental, management, and soil-related factors regarding their prediction potential on SOC stock changes between the tillage categories NT, RT, and CT. C concentrations and stocks to a certain depth were generally highest under NT, intermediate under RT, and lowest under CT. However, this effect was mainly limited to the first 15 cm and disappeared or was even reversed in deeper layers, especially when adjusting soil depth according to the equivalent soil mineral mass. Our study highlights the impact of tillage-induced changes in soil bulk density between treatments and shows that neglecting the principles of equivalent soil mass leads to overestimation of SOC stocks for by conservation tillage practices.

  7. Bioelectric potentials in the soil-plant system

    Science.gov (United States)

    Pozdnyakov, A. I.

    2013-07-01

    A detailed study of the electric potentials in the soil-plant system was performed. It was found that the electric potential depends on the plant species and the soil properties. A theoretical interpretation of the obtained data was given. All the plants, independently from their species and their state, always had a negative electric potential relative to the soil. The electric potential of the herbaceous plants largely depended on the leaf area. In some plants, such as burdock ( Arctium lappa) and hogweed ( Heracleum sosnowskyi), the absolute values of the negative electric potential exceeded 100 mV. The electric potential was clearly differentiated by the plant organs: in the flowers, it was lower than in the leaves; in the leaves, it was usually lower than in the leaf rosettes and stems. The electric potentials displayed seasonal dynamics. As a rule, the higher the soil water content, the lower the electric potential of the plants. However, an inverse relationship was observed for dandelions ( Taraxacum officinale). It can be supposed that the electric potential between the soil and the plant characterizes the vital energy of the plant.

  8. Seasonal Distribution of Nitrate and Nitrite Levels in Eleme Abattoir ...

    African Journals Online (AJOL)

    The study deals with the seasonal distribution of nitrate (NO3) and nitrite (NO2) levels in Eleme Abattoir environment. Samples of soil, surface water and groundwater were collected from areas unaffected and those affected by abattoir activities. For the soils from the affected area and control points respectively, nitrate levels ...

  9. Time-dependent depletion of nitrite in pork/beef and chicken meat products and its effect on nitrite intake estimation.

    Science.gov (United States)

    Merino, Leonardo; Darnerud, Per Ola; Toldrá, Fidel; Ilbäck, Nils-Gunnar

    2016-01-01

    The food additive nitrite (E249, E250) is commonly used in meat curing as a food preservation method. Because of potential negative health effects of nitrite, its use is strictly regulated. In an earlier study we have shown that the calculated intake of nitrite in children can exceed the acceptable daily intake (ADI) when conversion from dietary nitrate to nitrite is included. This study examined time-dependent changes in nitrite levels in four Swedish meat products frequently eaten by children: pork/beef sausage, liver paté and two types of chicken sausage, and how the production process, storage and also boiling (e.g., simmering in salted water) and frying affect the initial added nitrite level. The results showed a steep decrease in nitrite level between the point of addition to the product and the first sampling of the product 24 h later. After this time, residual nitrite levels continued to decrease, but much more slowly, until the recommended use-by date. Interestingly, this continuing decrease in nitrite was much smaller in the chicken products than in the pork/beef products. In a pilot study on pork/beef sausage, we found no effects of boiling on residual nitrite levels, but frying decreased nitrite levels by 50%. In scenarios of time-dependent depletion of nitrite using the data obtained for sausages to represent all cured meat products and including conversion from dietary nitrate, calculated nitrite intake in 4-year-old children generally exceeded the ADI. Moreover, the actual intake of nitrite from cured meat is dependent on the type of meat source, with a higher residual nitrite levels in chicken products compared with pork/beef products. This may result in increased nitrite exposure among consumers shifting their consumption pattern of processed meats from red to white meat products.

  10. Potentials' distribution in high resistivity soil around extended grounding electrodes

    Directory of Open Access Journals (Sweden)

    Ivonin V. V.

    2016-12-01

    Full Text Available The potential distribution in high resistivity soil around extended grounding electrodes has been described in the paper. The high-voltage polygon has been developed for experimental investigation. It is well known that direct or indirect lightning discharges could produce dangerous conditions for human body, as well as unwanted electromagnetic interferences among electrical and electronic systems. Therefore the electromagnetic characterization of earth electrodes under high pulse transient currents is an important highpoint in the design of a grounding system. The Marx generator was developed to generate impulse similar to lightning impulse. The potentials have been measured by the probe measurement system previously developed. Grounding resistance is the main characteristic of the grounding systems. From the literature analysis and experimental data it has been shown that steady state grounding resistance can differ from impulse grounding resistance. This phenomenon is caused by the ionization process and sparking occurring in the surrounding soil. Channel spark resistance is much less soil resistivity, therefore the soil resistivity and grounding resistance decrease. Calculations of potentials in the soil have been carried out using the finite element method. The experimental data have been compared with the results of the potential distribution calculation. It has been shown that the resulting spark channels in soils significantly affect the potential distribution. Accordingly, the sparking channels are to be considered while calculating the step voltage.

  11. Potentially pathogenic, pathogenic, and allergenic moulds in the urban soils

    Directory of Open Access Journals (Sweden)

    Đukić Dragutin A.

    2011-01-01

    Full Text Available The dynamics of soil mould populations that can compromise the human immune system was evaluated in experimental plots located at different distances (100, 300, 500, 700 and 900 m from the main source of pollution - the Podgorica Aluminum Plant. Soil samples were collected in July and October 2008 from three different plot zones at a depth of 0-10 cm. The count of potentially pathogenic, keratinolytic and allergenic (melaninogenic moulds was assessed, which can significantly contribute to both diagnosis and prophylaxis. The count of medically important moulds was higher in the urban soil than in the unpolluted (control soil. Their count decreased with increasing distance from the main pollution source (PAP. Their abundance in the soil was considerably higher in autumn than in spring.

  12. The potential of cover crops for improving soil function

    Science.gov (United States)

    Stoate, Chris; Crotty, Felicity

    2017-04-01

    Cover crops can be grown over the autumn and winter ensuring green cover throughout the year. They have been described as improving soil structure, reducing soil erosion and potentially even a form of grass weed control. These crops retain nutrients within the plant, potentially making them available for future crops, as well as increasing soil organic matter. Over the last three years, we have investigated how different cover crop regimes affect soil quality. Three separate experiments over each autumn/winter period have investigated how different cover crops affect soil biology, physics and chemistry, with each experiment building on the previous one. There have been significant effects of cover crops on soil structure, as well as significantly lower weed biomass and increased yields in the following crop - in comparison to bare stubble. For example, the effect of drilling the cover crops on soil structure in comparison to a bare stubble control that had not been driven on by machinery was quantified, and over the winter period the soil structure of the cover crop treatments changed, with compaction reduced in the cover crop treatments, whilst the bare stubble control remained unchanged. Weeds were found in significantly lower biomass in the cover crop mixes in comparison to the bare stubble control, and significantly lower weed biomass continued to be found in the following spring oat crop where the cover crops had been, indicating a weed suppressive effect that has a continued legacy in the following crop. The following spring oats have shown similar results in the last two years, with higher yields in the previous cover crop areas compared to the bare stubble controls. Overall, these results are indicating that cover crops have the potential to provide improvements to soil quality, reduce weeds and improve yields. We discuss the economic implications.

  13. Predictive mapping of the acidifying potential for acid sulfate soils

    DEFF Research Database (Denmark)

    Boman, A; Beucher, Amélie; Mattbäck, S

    Developing methods for the predictive mapping of the potential environmental impact from acid sulfate soils is important because recent studies (e.g. Mattbäck et al., under revision) have shown that the environmental hazards (e.g. leaching of acidity) related to acid sulfate soils vary depending...... on their texture (clay, silt, sand etc.). Moreover, acidity correlates, not only with the sulfur content, but also with the electrical conductivity (EC) measured after incubation. Electromagnetic induction (EMI) data collected from an EM38 proximal sensor also enabled the detailed mapping of acid sulfate soils...... over a field (Huang et al., 2014).This study aims at assessing the use of EMI data for the predictive mapping of the acidifying potential in an acid sulfate soil area in western Finland. Different supervised classification modelling techniques, such as Artificial Neural Networks (Beucher et al., 2015...

  14. Potential of ASCAT Soil Moisture Product to Improve Runoff Prediction

    Science.gov (United States)

    Brocca, L.; Melone, F.; Moramarco, T.; Wagner, W.; Naeimi, V.; Bartalis, Z.; Hasenauer, S.

    2009-11-01

    The role and the importance of soil moisture for meteorological, agricultural and hydrological applications is widely known. Remote sensing offers the unique capability to monitor soil moisture over large areas (catchment scale) with, nowadays, a temporal resolution suitable for hydrological purposes. However, the accuracy of the remotely sensed soil moisture estimates have to be carefully checked. Therefore, the assessment of the effects of assimilating satellite- derived soil moisture estimates into rainfall-runoff models at different scales and over different regions represents an important scientific and operational issue. In this context, the soil wetness index (SWI) product derived from the Advanced Scatterometer (ASCAT) sensor was tested in this study. The SWI was firstly compared with the soil moisture temporal pattern derived from a continuous rainfall-runoff model (MISDc). Then, by using a simple data assimilation technique, the SWI was assimilated into MISDc and the model performance on flood estimation was analyzed. Moreover, three synthetic experiments considering errors on rainfall, model parameters and initial soil wetness conditions were carried out. These experiments allowed to further investigate the SWI potential when uncertain conditions take place.The most significant flood events, which occurred in the period 2000-2009 for five subcatchments of the Upper Tiber River in central Italy, ranging in extension between 100 and 650 km2, were used as case studies. Results reveal that the SWI derived from the ASCAT sensor can be conveniently used to improve runoff prediction in the study area, mainly if the initial soil wetness conditions are unknown.

  15. Properties, classification and agricultural potentials of the soils of ...

    African Journals Online (AJOL)

    Properties, classification and agricultural potentials of the soils of lower Oshin river floodplains in Kwara State, Nigeria. ... Also, organic C content for topsoil was 27.5, 35.5 and 28.0 g kg-1 for OSH-1, OSH-2 and OSH-3 and its distribution within the profiles was irregular except in OSH-1 where it decreased regularly with soil ...

  16. Deep horizons: Soil Carbon sequestration and storage potential in grassland soils

    Science.gov (United States)

    Torres-Sallan, Gemma; Schulte, Rogier; Lanigan, Gary J.; Byrne, Kenneth A.; Reidy, Brian; Creamer, Rachel

    2016-04-01

    Soil Organic Carbon (SOC) enhances soil fertility, holding nutrients in a plant-available form. It also improves aeration and water infiltration. Soils are considered a vital pool for C (Carbon) sequestration, as they are the largest pool of C after the oceans, and contain 3.5 more C than the atmosphere. SOC models and inventories tend to focus on the top 30 cm of soils, only analysing total SOC values. Association of C with microaggregates (53-250 μm) and silt and clay (mineralization. This study assessed the role of aggregation in C sequestration throughout the profile, down to 1 m depth, of 30 grassland sites divided in 6 soil types. One kg sample was collected for each horizon, sieved at 8 mm and dried at 40 °C. Through a wet sieving procedure, four aggregate sizes were isolated: large macroaggregates (>2000 μm); macroaggregates (250-2000 μm); microaggregates and silt & clay. Organic C associated to each aggregate fraction was analysed on a LECO combustion analyser. Sand-free C was calculated for each aggregate size. For all soil types, 84% of the SOC located in the first 30 cm was contained inside macroaggregates and large macroaggregates. Given that this fraction has a turnover time of 1 to 10 years, sampling at that depth only provides information on the labile fraction in soil, and does not consider the longer term C sequestration potential. Only when looking at the whole profile, two clear trends could be observed: 1) soils with a clay increase at depth had most of their C located in the silt and clay fractions, which indicate their enhanced C sequestration capacity, 2) free-draining soils had a bigger part of their SOC located in the macroaggregate fractions. These results indicate that current C inventories and models that focus on the top 30 cm, do not accurately measure soil C sequestration potential in soils, but rather the more labile fraction. However, at depth soil forming processes have been identified as a major factor influencing C

  17. Immobilization of potentially toxic metals using different soil amendments.

    Science.gov (United States)

    Tica, D; Udovic, M; Lestan, D

    2011-10-01

    The in situ stabilization of potentially toxic metals (PTMs), using various easily available amendments, is a cost-effective remediation method for contaminated soils. In the present study, we investigated the effectiveness of apatite and a commercial mixture of dolomite, diatomite, smectite basaltic tuff, bentonite, alginite and zeolite (Slovakite) on Pb, Zn, Cu and Cd stabilization by means of decreasing their bioavailability in contaminated soil from an old lead and zinc smelter site in Arnoldstein, Austria. We also investigated the impact of 5% (w/w) apatite and Slovakite applications on soil functionality and quality, as assessed by glucose-induced soil respiration, dehydrogenase, acid and alkaline phosphatase and β-glucosidase activity. Both amendments resulted in increased soil pH and decreased PTM potential bioavailability assessed by diethylenetriamine pentaacetic acid extraction and by sequential extractions in the water-soluble and exchangeable fractions. The efficiency of stabilization was reflected in the soil respiration rate and in enzymatic activity. The β-glucosidase activity assay was the most responsive of them. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Application of remote sensing to estimating soil erosion potential

    Science.gov (United States)

    Morris-Jones, D. R.; Kiefer, R. W.

    1980-01-01

    A variety of remote sensing data sources and interpretation techniques has been tested in a 6136 hectare watershed with agricultural, forest and urban land cover to determine the relative utility of alternative aerial photographic data sources for gathering the desired land use/land cover data. The principal photographic data sources are high altitude 9 x 9 inch color infrared photos at 1:120,000 and 1:60,000 and multi-date medium altitude color and color infrared photos at 1:60,000. Principal data for estimating soil erosion potential include precipitation, soil, slope, crop, crop practice, and land use/land cover data derived from topographic maps, soil maps, and remote sensing. A computer-based geographic information system organized on a one-hectare grid cell basis is used to store and quantify the information collected using different data sources and interpretation techniques. Research results are compared with traditional Universal Soil Loss Equation field survey methods.

  19. Assessment of Soil Liquefaction Potential Based on Numerical Method

    DEFF Research Database (Denmark)

    Choobasti, A. Janalizadeh; Vahdatirad, Mohammad Javad; Torabi, M.

    2012-01-01

    , a zone of the corridor of Tabriz urban railway line 2 susceptible to liquefaction was recognized. Then, using numerical analysis and cyclic stress method using QUAKE/W finite element code, soil liquefaction potential in susceptible zone was evaluated based on design earthquake....... simplified method have been developed over the years. Although simplified methods are available in calculating the liquefaction potential of a soil deposit and shear stresses induced at any point in the ground due to earthquake loading, these methods cannot be applied to all earthquakes with the same...

  20. Global Sequestration Potential of Increased Organic Carbon in Cropland Soils.

    Science.gov (United States)

    Zomer, Robert J; Bossio, Deborah A; Sommer, Rolf; Verchot, Louis V

    2017-11-14

    The role of soil organic carbon in global carbon cycles is receiving increasing attention both as a potentially large and uncertain source of CO 2 emissions in response to predicted global temperature rises, and as a natural sink for carbon able to reduce atmospheric CO 2 . There is general agreement that the technical potential for sequestration of carbon in soil is significant, and some consensus on the magnitude of that potential. Croplands worldwide could sequester between 0.90 and 1.85 Pg C/yr, i.e. 26-53% of the target of the "4p1000 Initiative: Soils for Food Security and Climate". The importance of intensively cultivated regions such as North America, Europe, India and intensively cultivated areas in Africa, such as Ethiopia, is highlighted. Soil carbon sequestration and the conservation of existing soil carbon stocks, given its multiple benefits including improved food production, is an important mitigation pathway to achieve the less than 2 °C global target of the Paris Climate Agreement.

  1. Pesticide sorption and leaching potential on three Hawaiian soils.

    Science.gov (United States)

    Hall, Kathleen E; Ray, Chittaranjan; Ki, Seo Jin; Spokas, Kurt A; Koskinen, William C

    2015-08-15

    On the Hawaiian Islands, groundwater is the principal source of potable water and contamination of this key resource by pesticides is of great concern. To evaluate the leaching potential of four weak acid herbicides [aminocyclopyrachlor, picloram, metsulfuron-methyl, biologically active diketonitrile degradate of isoxaflutole (DKN)] and two neutral non-ionizable herbicides [oxyfluorfen, alachlor], their sorption coefficients were determined on three prevalent soils from the island of Oahu. Metsulfuron-methyl, aminocylcopyrachlor, picloram, and DKN were relatively low sorbing herbicides (K(oc) = 3-53 mL g(-1)), alachlor was intermediate (K(oc) = 120-150 mL g(-1)), and oxyfluorfen sorbed very strongly to the three soils (K(oc) > 12,000 mL g(-1)). Following determination of K(oc) values, the groundwater ubiquity score (GUS) indices for these compounds were calculated to predicted their behavior with the Comprehensive Leaching Risk Assessment System (CLEARS; Tier-1 methodology for Hawaii). Metsulfuron-methyl, aminocyclopyrachlor, picloram, and DKN would be categorized as likely leachers in all three Hawaiian soils, indicating a high risk of groundwater contamination across the island of Oahu. In contrast, oxyfluorfen, regardless of the degradation rate, would possess a low and acceptable leaching risk due to its high sorption on all three soils. The leaching potential of alachlor was more difficult to classify, with a GUS value between 1.8 and 2.8. In addition, four different biochar amendments to these soils did not significantly alter their sorption capacities for aminocyclopyrachlor, indicating a relatively low impact of black carbon additions from geologic volcanic inputs of black carbon. Due to the fact that pesticide environmental risks are chiefly dependent on local soil characteristics, this work has demonstrated that once soil specific sorption parameters are known one can assess the potential pesticide leaching risks. Published by Elsevier Ltd.

  2. Agricultural soils potentially contaminated: risk assessment procedure case studies

    Directory of Open Access Journals (Sweden)

    Eleonora Beccaloni

    2010-01-01

    Full Text Available At the moment, the health-environmental risk analysis is used to decision-making targets in the contaminated sites management; this procedure allows to assess the quantitative health risk related to the pollutants presence in environmental compartments, as soil and waters. As regards potentially contaminated agricultural soils, the ingestion of food from vegetable and/or animal source, produced inside the contaminated area, is the most suitable way to assess the health risk. As an official procedure to this assessment is not available, the National Institute for Health (Istituto Superiore di Sanità, ISS has worked out an operating procedure, organized into several phases, depending on the available specific-site know-how. In this document, agricultural soils potentially contaminated in two sites have been studied; the sites are the following: Brescia Caffaro and Torviscosa.

  3. Diversity of nitrite reductase (nirK and nirS) gene fragments in forested upland and wetland soils

    DEFF Research Database (Denmark)

    Priemé, Anders; Braker, Gesche; Tiedje, James M.

    2002-01-01

    marsh clones and all upland clones. Only a few of the nirK clone sequences branched with those of known denitrifying bacteria. The nirS clones formed two major clusters with several subclusters, but all nirS clones showed less than 80% identity to nirS sequences from known denitrifying bacteria. Overall...... pattern was found in both soils and in each soil two dominant groups comprised >35% of all clones. No dominance and few redundant patterns were seen among the nirS clones. Phylogenetic analysis of deduced amino acids grouped the nirK sequences into five major clusters, with one cluster encompassing most...

  4. Measuring Soil Water Potential for Water Management in Agriculture: A Review

    OpenAIRE

    Marco Bittelli

    2010-01-01

    Soil water potential is a soil property affecting a large variety of bio-physical processes, such as seed germination, plant growth and plant nutrition. Gradients in soil water potential are the driving forces of water movement, affecting water infiltration, redistribution, percolation, evaporation and plants’ transpiration. The total soil water potential is given by the sum of gravity, matric, osmotic and hydrostatic potential. The quantification of the soil water potential is necessary for ...

  5. EFFECT OF SOIL WATER POTENTIAL ON TRANSPIRATION RATE IN CUCUMBER PLANTS

    OpenAIRE

    Cho, Tosio; Eguchi, Hiromi; Kuroda, Masaharu; Tanaka, Akira; Koutaki, Masahiro; Ng, Ah Lek; Matsui, Tsuyoshi

    1985-01-01

    In an attempt to examine the effect of soil water potential (pF) on transpiration rate, leaf temperature of cucumber plants was measured under various conditions of soil water potential, and transpiration rate was calculated from heat balance of the leaf. Transpiration rate decreased with reduction in soil water potential; transpiration rate dropped at soil water potentials lower than pF 3.0. This fact suggests that the reduction in soil water potential restricts water uptake in roots and cau...

  6. Ipomea asarifolia (Desr), A Potential Cover Crop for Soil Fertility ...

    African Journals Online (AJOL)

    Ipomea asarifolia (Desr), A Potential Cover Crop for Soil Fertility Improvement in The Sudan Savanna Region, Nigeria. ... University main Campus; VC complex area, University stadium area, Behind new library area and opposite IBB centre area and four distances from the plant (control, plant base, 0.5 m and 1 m from the ...

  7. Selected soil enzymes: Examples of their potential roles in the ...

    African Journals Online (AJOL)

    Soil enzymes regulate ecosystem functioning and in particular play a key role in nutrient cycling. In this review we briefly summarise potential roles of selected enzymes such as amylase, arylsulphatases, -glucosidase, cellulose, chitinase, dehydrogenase, phosphatase, protease and urease in the ecosystem. We also ...

  8. Arabian Red Sea coastal soils as potential mineral dust sources

    KAUST Repository

    Prakash, P. Jish

    2016-09-26

    Both Moderate Resolution Imaging Spectroradiometer (MODIS) and Spinning Enhanced Visible and InfraRed Imager (SEVIRI) satellite observations suggest that the narrow heterogeneous Red Sea coastal region is a frequent source of airborne dust that, because of its proximity, directly affects the Red Sea and coastal urban centers. The potential of soils to be suspended as airborne mineral dust depends largely on soil texture, moisture content and particle size distributions. Airborne dust inevitably carries the mineralogical and chemical signature of a parent soil. The existing soil databases are too coarse to resolve the small but important coastal region. The purpose of this study is to better characterize the mineralogical, chemical and physical properties of soils from the Arabian Red Sea coastal plain, which in turn will help to improve assessment of dust effects on the Red Sea, land environmental systems and urban centers. Thirteen surface soils from the hot-spot areas of windblown mineral dust along the Red Sea coastal plain were sampled for analysis. Analytical methods included optical microscopy, X-ray diffraction (XRD), inductively coupled plasma optical emission spectrometry (ICP-OES), ion chromatography (IC), scanning electron microscopy (SEM) and laser particle size analysis (LPSA). We found that the Red Sea coastal soils contain major components of quartz and feldspar, as well as lesser but variable amounts of amphibole, pyroxene, carbonate, clays and micas, with traces of gypsum, halite, chlorite, epidote and oxides. The range of minerals in the soil samples was ascribed to the variety of igneous and metamorphic provenance rocks of the Arabian Shield forming the escarpment to the east of the Red Sea coastal plain. The analysis revealed that the samples contain compounds of nitrogen, phosphorus and iron that are essential nutrients to marine life. The analytical results from this study will provide a valuable input into dust emission models used in climate

  9. Arabian Red Sea coastal soils as potential mineral dust sources

    Science.gov (United States)

    Jish Prakash, P.; Stenchikov, Georgiy; Tao, Weichun; Yapici, Tahir; Warsama, Bashir; Engelbrecht, Johann P.

    2016-09-01

    Both Moderate Resolution Imaging Spectroradiometer (MODIS) and Spinning Enhanced Visible and InfraRed Imager (SEVIRI) satellite observations suggest that the narrow heterogeneous Red Sea coastal region is a frequent source of airborne dust that, because of its proximity, directly affects the Red Sea and coastal urban centers. The potential of soils to be suspended as airborne mineral dust depends largely on soil texture, moisture content and particle size distributions. Airborne dust inevitably carries the mineralogical and chemical signature of a parent soil. The existing soil databases are too coarse to resolve the small but important coastal region. The purpose of this study is to better characterize the mineralogical, chemical and physical properties of soils from the Arabian Red Sea coastal plain, which in turn will help to improve assessment of dust effects on the Red Sea, land environmental systems and urban centers. Thirteen surface soils from the hot-spot areas of windblown mineral dust along the Red Sea coastal plain were sampled for analysis. Analytical methods included optical microscopy, X-ray diffraction (XRD), inductively coupled plasma optical emission spectrometry (ICP-OES), ion chromatography (IC), scanning electron microscopy (SEM) and laser particle size analysis (LPSA). We found that the Red Sea coastal soils contain major components of quartz and feldspar, as well as lesser but variable amounts of amphibole, pyroxene, carbonate, clays and micas, with traces of gypsum, halite, chlorite, epidote and oxides. The range of minerals in the soil samples was ascribed to the variety of igneous and metamorphic provenance rocks of the Arabian Shield forming the escarpment to the east of the Red Sea coastal plain. The analysis revealed that the samples contain compounds of nitrogen, phosphorus and iron that are essential nutrients to marine life. The analytical results from this study will provide a valuable input into dust emission models used in climate

  10. Arabian Red Sea coastal soils as potential mineral dust sources

    Directory of Open Access Journals (Sweden)

    P. Jish Prakash

    2016-09-01

    Full Text Available Both Moderate Resolution Imaging Spectroradiometer (MODIS and Spinning Enhanced Visible and InfraRed Imager (SEVIRI satellite observations suggest that the narrow heterogeneous Red Sea coastal region is a frequent source of airborne dust that, because of its proximity, directly affects the Red Sea and coastal urban centers. The potential of soils to be suspended as airborne mineral dust depends largely on soil texture, moisture content and particle size distributions. Airborne dust inevitably carries the mineralogical and chemical signature of a parent soil. The existing soil databases are too coarse to resolve the small but important coastal region. The purpose of this study is to better characterize the mineralogical, chemical and physical properties of soils from the Arabian Red Sea coastal plain, which in turn will help to improve assessment of dust effects on the Red Sea, land environmental systems and urban centers. Thirteen surface soils from the hot-spot areas of windblown mineral dust along the Red Sea coastal plain were sampled for analysis. Analytical methods included optical microscopy, X-ray diffraction (XRD, inductively coupled plasma optical emission spectrometry (ICP-OES, ion chromatography (IC, scanning electron microscopy (SEM and laser particle size analysis (LPSA. We found that the Red Sea coastal soils contain major components of quartz and feldspar, as well as lesser but variable amounts of amphibole, pyroxene, carbonate, clays and micas, with traces of gypsum, halite, chlorite, epidote and oxides. The range of minerals in the soil samples was ascribed to the variety of igneous and metamorphic provenance rocks of the Arabian Shield forming the escarpment to the east of the Red Sea coastal plain. The analysis revealed that the samples contain compounds of nitrogen, phosphorus and iron that are essential nutrients to marine life. The analytical results from this study will provide a valuable input into dust emission models

  11. Soil Degradation in India: Challenges and Potential Solutions

    Directory of Open Access Journals (Sweden)

    Ranjan Bhattacharyya

    2015-03-01

    Full Text Available Soil degradation in India is estimated to be occurring on 147 million hectares (Mha of land, including 94 Mha from water erosion, 16 Mha from acidification, 14 Mha from flooding, 9 Mha from wind erosion, 6 Mha from salinity, and 7 Mha from a combination of factors. This is extremely serious because India supports 18% of the world’s human population and 15% of the world’s livestock population, but has only 2.4% of the world’s land area. Despite its low proportional land area, India ranks second worldwide in farm output. Agriculture, forestry, and fisheries account for 17% of the gross domestic product and employs about 50% of the total workforce of the country. Causes of soil degradation are both natural and human-induced. Natural causes include earthquakes, tsunamis, droughts, avalanches, landslides, volcanic eruptions, floods, tornadoes, and wildfires. Human-induced soil degradation results from land clearing and deforestation, inappropriate agricultural practices, improper management of industrial effluents and wastes, over-grazing, careless management of forests, surface mining, urban sprawl, and commercial/industrial development. Inappropriate agricultural practices include excessive tillage and use of heavy machinery, excessive and unbalanced use of inorganic fertilizers, poor irrigation and water management techniques, pesticide overuse, inadequate crop residue and/or organic carbon inputs, and poor crop cycle planning. Some underlying social causes of soil degradation in India are land shortage, decline in per capita land availability, economic pressure on land, land tenancy, poverty, and population increase. In this review of land degradation in India, we summarize (1 the main causes of soil degradation in different agro-climatic regions; (2 research results documenting both soil degradation and soil health improvement in various agricultural systems; and (3 potential solutions to improve soil health in different regions using a

  12. Upconversion nanoparticles for ratiometric fluorescence detection of nitrite.

    Science.gov (United States)

    Han, Junfen; Zhang, Cheng; Liu, Fei; Liu, Bianhua; Han, Mingyong; Zou, Wensheng; Yang, Liang; Zhang, Zhongping

    2014-06-21

    We have developed a selective upconversion switching method for the ratiometric fluorescence detection of nitrite using upconversion nanoparticles (UCNPs) and an efficient nitrite reaction. The green emission (λ(em) = 539 nm) of NaYF4:Yb(3+),Er(3+) nanoparticles can be selectively quenched by the neutral red (NR) dye due to the spectral overlap between the emission at 539 nm and the absorption of NR, while its red emission (λ(em) = 654 nm) remains unchanged. Nitrite reacts specifically and strongly with NR to form diazonium salt and lose the diazonium group, which sharply decreases the absorption of NR. Thus, the green emission of NaYF4:Yb(3+),Er(3+) can be recovered by increasing the amount of nitrite, leading to visible color changes from red to orange-yellow and finally green under excitation at 980 nm. The increase in the ratio of emission intensities (I539/I654) is quantitatively correlated to the concentration of nitrite ions. Moreover, the developed method has been successfully applied to nitrite detection in real samples such as drinking water, natural water and meat foods. In particular, the upconversion sensors can efficiently avoid background optical interference and thus show potential for the detection of nitrite salts in complex samples.

  13. Biological soil crusts: Diminutive communities of potential global importance

    Science.gov (United States)

    Ferrenberg, Scott; Tucker, Colin; Reed, Sasha C.

    2017-01-01

    Biological soil crusts (biocrusts) are widespread, diverse communities of cyanobacteria, fungi, lichens, and mosses living on soil surfaces, primarily in drylands. Biocrusts can locally govern primary production, soil fertility, hydrology, and surface energy balance, with considerable variation in these functions across alternate community states. Further, these communities have been implicated in Earth system functioning via potential influences on global biogeochemistry and climate. Biocrusts are easily destroyed by disturbances and appear to be exceptionally vulnerable to warming temperatures and altered precipitation inputs, signaling possible losses of dryland functions with global change. Despite these concerns, we lack sufficient spatiotemporal data on biocrust function, cover, and community structure to confidently assess their ecological roles across the extensive dryland biome. Here, we present the case for cross-scale research and restoration efforts coupled with remote-sensing and modeling approaches that improve our collective understanding of biocrust responses to global change and the ecological roles of these diminutive communities at global scales.

  14. Novel genes for nitrite reductase and Amo-related proteins indicate a role of uncultivated mesophilic crenarchaeota in nitrogen cycling

    DEFF Research Database (Denmark)

    Treusch, Alexander H; Leininger, Sven; Kletzin, Arnulf

    2005-01-01

    Mesophilic crenarchaeota are frequently found in terrestrial and marine habitats worldwide, but despite their considerable abundance the physiology of these as yet uncultivated archaea has remained unknown. From a 1.2 Gb large-insert environmental fosmid library of a calcareous grassland soil, a 43...... kb genomic fragment was isolated with a ribosomal RNA that shows its affiliation to group 1.1b of crenarchaeota repeatedly found in soils. The insert encoded a homologue of a copper-containing nitrite reductase with an unusual C-terminus that encoded a potential amicyanin-like electron transfer...

  15. Soil liquefaction potential in Eskişehir, NW Turkey

    Directory of Open Access Journals (Sweden)

    H. Tosun

    2011-04-01

    Full Text Available Liquefaction is one of the critical problems in geotechnical engineering. High ground water levels and alluvial soils have a high potential risk for damage due to liquefaction, especially in seismically active regions. Eskişehir urban area, studied in this article, is situated within the second degree earthquake region on the seismic hazard zonation map of Turkey and is surrounded by Eskişehir, North Anatolian, Kütahya and Simav Fault Zones. Geotechnical investigations are carried out in two stages: field and laboratory. In the first stage, 232 boreholes in different locations were drilled and Standard Penetration Test (SPT was performed. Test pits at 106 different locations were also excavated to support geotechnical data obtained from field tests. In the second stage, experimental studies were performed to determine the Atterberg limits and physical properties of soils. Liquefaction potential was investigated by a simplified method based on SPT. A scenario earthquake of magnitude M=6.4, produced by Eskişehir Fault Zone, was used in the calculations. Analyses were carried out for PGA levels at 0.19, 0.30 and 0.47 g. The results of the analyses indicate that presence of high ground water level and alluvial soil increase the liquefaction potential with the seismic features of the region. Following the analyses, liquefaction potential maps were produced for different depth intervals and can be used effectively for development plans and risk management practices in Eskişehir.

  16. Soil liquefaction potential in Eskişehir, NW Turkey

    Science.gov (United States)

    Tosun, H.; Seyrek, E.; Orhan, A.; Savaş, H.; Türköz, M.

    2011-04-01

    Liquefaction is one of the critical problems in geotechnical engineering. High ground water levels and alluvial soils have a high potential risk for damage due to liquefaction, especially in seismically active regions. Eskişehir urban area, studied in this article, is situated within the second degree earthquake region on the seismic hazard zonation map of Turkey and is surrounded by Eskişehir, North Anatolian, Kütahya and Simav Fault Zones. Geotechnical investigations are carried out in two stages: field and laboratory. In the first stage, 232 boreholes in different locations were drilled and Standard Penetration Test (SPT) was performed. Test pits at 106 different locations were also excavated to support geotechnical data obtained from field tests. In the second stage, experimental studies were performed to determine the Atterberg limits and physical properties of soils. Liquefaction potential was investigated by a simplified method based on SPT. A scenario earthquake of magnitude M=6.4, produced by Eskişehir Fault Zone, was used in the calculations. Analyses were carried out for PGA levels at 0.19, 0.30 and 0.47 g. The results of the analyses indicate that presence of high ground water level and alluvial soil increase the liquefaction potential with the seismic features of the region. Following the analyses, liquefaction potential maps were produced for different depth intervals and can be used effectively for development plans and risk management practices in Eskişehir.

  17. Potential of soil liquefaction at Perlis, northern region of Malalysia

    Science.gov (United States)

    Ghazaly, Zuhayr Md; Rahim, Mustaqqim Abdul; Nasir, Mohamad Amzar Bin Mhd; Isa, Nur Fitriah; Zaki, Mohd Faiz Mohammad; Hassan, Zulkarnain Bin; Ismail, Zul-Atfi Bin

    2017-09-01

    Soil liquefaction is earthquake's secondary effect which could cause fatal damages and structures instability. Despite Malaysia been located in stable zone of Pacific Ring of Fire, few significant surrounded quakes like Sumatra-Andaman earthquake had prompted Malaysian's public concern, especially in Perlis area, on local seismic resistant. Hence, this research presents the analysis result of liquefaction potential of the soils, as the secondary effect of earthquake, within Perlis, northern region of Malaysia; the next strong and sustainable metropolis by using semi-empirical procedures introduced by Seed and Idriss. The study consists of two stages which were determination of the local geological and geotechnical site conditions within Perlis and analysis of soil liquefaction susceptibility by using various methods and liquefaction potential by using Simplified Procedure developed by Seed and Idriss on stress approach. There were consist of four phases implemented in order to achieve the objectives targeted for the study after problem being identified. Firstly, a comprehensive review of literature on liquefaction at Perlis was carried out. Second phase was data collection process that includes collection of Site Investigation (SI) report. Thirdly, data analysis was carried out by utilizing suitable method. The final phase was to draw conclusion and recommendation for this study. It can be concluded that the overall Perlis due to earthquake moment magnitude below 7.5 has no potential to soil liquefaction. However, with the range of liquefaction potential of 1.60 to 5.64 in Kuala Perlis area, it is liquefiable. The development of liquefaction severity map of Perlis, Malaysia in this research, may be used by others as a reference for seismic design and standard safety measures as well as for further research work.

  18. Modelling in situ enzyme potential of soils: a tool to predict soil respiration from agricultural fields

    Science.gov (United States)

    Shahbaz Ali, Rana; Poll, Christian; Demyan, Scott; Nkwain Funkuin, Yvonne; Ingwersen, Joachim; Wizemann, Hans-Dieter; Kandeler, Ellen

    2014-05-01

    The fate of soil organic carbon (SOC) is one of the largest uncertainties in predicting future climate and terrestrial ecosystem functions. Extra-cellular enzymes, produced by microorganisms, perform the very first step in SOC degradation and serve as key components in global carbon cycling. Very little information is available about the seasonal variation in the temperature sensitivity of soil enzymes. Here we aim to model in situ enzyme potentials involved in the degradation of either labile or recalcitrant organic compounds to understand the temporal variability of degradation processes. To identify the similarities in seasonal patterns of soil respiration and in situ enzyme potentials, we compared the modelled in situ enzyme activities with weekly measured soil CO2 emissions. Arable soil samples from two different treatments (4 years fallow and currently vegetated plots; treatments represent range of carbon input into soil) were collected every month from April, 2012 to April, 2013, from two different study regions (Kraichgau and Swabian Alb) in Southwest Germany. The vegetation plots were under crop rotation in both study areas. We measured activities of three enzymes including β-glucosidase, xylanase and phenoloxidase at five different temperatures. We also measured soil microbial biomass in form of microbial carbon (Cmic). Land-use and area had significant effects (P < 0.001) on the microbial biomass; fallow plots having less Cmic than vegetation plots. Potential activities of β-glucosidase (P < 0.001) and xylanase (P < 0.01) were significantly higher in the vegetation plots of the Swabian Alb region than in the Kraichgau region. In both study areas, enzyme activities were higher during vegetation period and lower during winter which points to the importance of carbon input and/or temperature and soil moisture. We calculated the temperature sensitivity (Q10) of enzyme activities based on laboratory measurements of enzyme activities at a range of incubation

  19. Can soil Chytridiomycota survive and grow in different osmotic potentials?

    Science.gov (United States)

    Gleason, Frank H; Midgley, David J; Letcher, Peter M; McGee, Peter A

    2006-07-01

    Twenty isolates from soil in the orders Spizellomycetales, Blastocladiales and Chytridiales (Chytridiomycota) grew on complex solid media supplemented with 10 gl(-1) sodium chloride. In a synthetic liquid medium, 4.4 gl(-1) sodium chloride strongly inhibited growth in three of the five isolates, possibly because of the effect of the ions or osmolarity of the solution. The maximum concentration for growth in synthetic liquid medium with different osmotic potentials using polyethylene glycol (PEG) varied considerably amongst the isolates. Three patterns of growth with increasing concentrations of PEG were evident among isolates within the genus Rhizophydium. Up to the concentration where growth ceased, the dry weight of each isolate either decreased, remained constant, or in one case, increased. Most of the fungi survived when incubated at room temperature for 7d in complex liquid media supplemented with 35 gl(-1) sodium chloride or 300 gl(-1) PEG. These data indicate that soil Chytridiomycota can survive various osmotic potentials that may occur during the wetting and drying phases in soils.

  20. Recent structural insights into the function of copper nitrite reductases.

    Science.gov (United States)

    Horrell, Sam; Kekilli, Demet; Strange, Richard W; Hough, Michael A

    2017-11-15

    Copper nitrite reductases (CuNiR) carry out the first committed step of the denitrification pathway of the global nitrogen cycle, the reduction of nitrite (NO 2 - ) to nitric oxide (NO). As such, they are of major agronomic and environmental importance. CuNiRs occur primarily in denitrifying soil bacteria which carry out the overall reduction of nitrate to dinitrogen. In this article, we review the insights gained into copper nitrite reductase (CuNiR) function from three dimensional structures. We particularly focus on developments over the last decade, including insights from serial femtosecond crystallography using X-ray free electron lasers (XFELs) and from the recently discovered 3-domain CuNiRs.

  1. Measuring Soil Water Potential for Water Management in Agriculture: A Review

    Directory of Open Access Journals (Sweden)

    Marco Bittelli

    2010-05-01

    Full Text Available Soil water potential is a soil property affecting a large variety of bio-physical processes, such as seed germination, plant growth and plant nutrition. Gradients in soil water potential are the driving forces of water movement, affecting water infiltration, redistribution, percolation, evaporation and plants’ transpiration. The total soil water potential is given by the sum of gravity, matric, osmotic and hydrostatic potential. The quantification of the soil water potential is necessary for a variety of applications both in agricultural and horticultural systems such as optimization of irrigation volumes and fertilization. In recent decades, a large number of experimental methods have been developed to measure the soil water potential, and a large body of knowledge is now available on theory and applications. In this review, the main techniques used to measure the soil water potential are discussed. Subsequently, some examples are provided where the measurement of soil water potential is utilized for a sustainable use of water resources in agriculture.

  2. Allelopatic potential of weeds under the minimalization of soil treatment

    Directory of Open Access Journals (Sweden)

    Mikhail A. Mazirov

    2014-01-01

    Full Text Available The content of water-dispersible phenol substances in rhizosphere both of annual and perennial species of weeds (Cirsium arvense, Sonchus arvensis increases under soil treatment minimalization. The higher content of phenol substances of researched weeds is defined in rhizosphere of Common Couch (Agropyrum repens. The absence of intensive anthropogenic treatment of plowing layer which accumulates the significant mass of weed’s roots in the cause of much more higher allelopathic potential of some species’ of weeds. The high level of saturation by weeds in agrophytocoenosis under non-tillage soil treatment is defines the competitiveness between certain sepsis’ of weeds, especially, at the beginning of the vegetation. In this case, increasing the secretion of phenol substances is one of the physiological screenings of such competitiveness.

  3. Potential impact of soil microbial heterogeneity on the persistence of hydrocarbons in contaminated subsurface soils.

    Science.gov (United States)

    Aleer, Sam; Adetutu, Eric M; Weber, John; Ball, Andrew S; Juhasz, Albert L

    2014-04-01

    In situ bioremediation is potentially a cost effective treatment strategy for subsurface soils contaminated with petroleum hydrocarbons, however, limited information is available regarding the impact of soil spatial heterogeneity on bioremediation efficacy. In this study, we assessed issues associated with hydrocarbon biodegradation and soil spatial heterogeneity (samples designated as FTF 1, 5 and 8) from a site in which in situ bioremediation was proposed for hydrocarbon removal. Test pit activities showed similarities in FTF soil profiles with elevated hydrocarbon concentrations detected in all soils at 2 m below ground surface. However, PCR-DGGE-based cluster analysis showed that the bacterial community in FTF 5 (at 2 m) was substantially different (53% dissimilar) and 2-3 fold more diverse than communities in FTF 1 and 8 (with 80% similarity). When hydrocarbon degrading potential was assessed, differences were observed in the extent of (14)C-benzene mineralisation under aerobic conditions with FTF 5 exhibiting the highest hydrocarbon removal potential compared to FTF 1 and 8. Further analysis indicated that the FTF 5 microbial community was substantially different from other FTF samples and dominated by putative hydrocarbon degraders belonging to Pseudomonads, Xanthomonads and Enterobacteria. However, hydrocarbon removal in FTF 5 under anaerobic conditions with nitrate and sulphate electron acceptors was limited suggesting that aerobic conditions were crucial for hydrocarbon removal. This study highlights the importance of assessing available microbial capacity prior to bioremediation and shows that the site's spatial heterogeneity can adversely affect the success of in situ bioremediation unless area-specific optimizations are performed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Nitrate and nitrite content of human, formula, bovine, and soy milks: implications for dietary nitrite and nitrate recommendations.

    Science.gov (United States)

    Hord, Norman G; Ghannam, Janine S; Garg, Harsha K; Berens, Pamela D; Bryan, Nathan S

    2011-12-01

    Estimation of nitrate and nitrite concentrations of milk sources may provide insight into potential health risks and benefits of these food sources for infants, children, and adults. The World Health Organization and American Academy of Pediatrics recommends exclusive consumption of human milk for the first 6 months of life. Human milk is known to confer significant nutritional and immunological benefits for the infant. Consumption of formula, cow's, and soy milk may be used as alternatives to human milk for infants. We sought to estimate potential exposure to nitrate and nitrite in human, formula, bovine, and soy milk to inform total dietary exposure estimates and recommendations. Using sensitive quantitative methodologies, nitrite and nitrate were analyzed in different samples of milk. Human milk concentrations of colostrum (expressed days 1-3 postpartum; n=12), transition milk (expressed days 3-7 postpartum; n=17), and mature milk (expressed >7 days postpartum; n=50) were 0.08 mg/100 mL nitrite and 0.19 mg/100 mL nitrate, 0.001 mg/100 mL nitrite and 0.52 mg/100 mL nitrate, and 0.001 mg/100 mL nitrite and 0.3 mg/100 mL nitrate, respectively, revealing that the absolute amounts of these anions change as the composition of milk changes. When expressed as a percentage of the World Health Organization's Acceptable Daily Intake limits, Silk® Soy Vanilla (WhiteWave Foods, Broomfield, CO) intake could result in high nitrate intakes (104% of this standard), while intake of Bright Beginnings Soy Pediatric® formula (PBM Nutritionals, Georgia, VT) could result in the highest nitrite intakes (383% of this standard). The temporal relationship between the provision of nitrite in human milk and the development of commensal microbiota capable of reducing dietary nitrate to nitrite supports a hypothesis that humans are adapted to provide nitrite to the gastrointestinal tract from birth. These data support the hypothesis that the high concentrations of

  5. Effect of Nitrite Inhibitor on the Macrocell Corrosion Behavior of Reinforcing Steel

    Directory of Open Access Journals (Sweden)

    Zhonglu Cao

    2015-01-01

    Full Text Available The effect of nitrite ions on the macrocell corrosion behavior of reinforcing steel embedded in cement mortar was investigated by comparing and analyzing the macrocell corrosion current, macrocell polarization ratios, and slopes of anodic and cathodic steels. Based on the experimental results, the relationship between macrocell potential difference and macrocell current density was analyzed, and the mechanism of macrocell corrosion affected by nitrite ions was proposed. The results indicated that nitrite ions had significant impact on the macrocell polarization ratios of cathode and anode. The presence of nitrite could reduce the macrocell current by decreasing the macrocell potential difference and increasing the macrocell polarization resistance of the anode.

  6. Effect of Soil Aging on the Phytoremediation Potential of Zea mays in Chromium and Benzo[a]Pyrene Contaminated Soils.

    Science.gov (United States)

    Chigbo, Chibuike

    2015-06-01

    This study compared the phytoremediation potential of Zea mays in soil either aged or freshly amended with chromium (Cr) and benzo[a]pyrene (B[a]P). Z. mays showed increased shoot biomass in aged soils than in freshly spiked soils. The shoot biomass in contaminated soils increased by over 50% in aged soil when compared to freshly amended soils, and over 29% more Cr was accumulated in the shoot of Z. mays in aged soil than in freshly amended soil. Planting Z. mays in aged soil helped in the dissipation of more than 31% B[a]P than in freshly spiked soil, but in the absence of plants, there seemed to be no difference between the dissipation rates of B[a]P in freshly and aged co-contaminated soil. Z. mays seemed to enhance the simultaneous removal of Cr and B[a]P in aged soil than in freshly spiked soil and hence can be a good plant choice for phytoremediation of co-contaminated soils.

  7. The Hepatoprotective Effect of Sodium Nitrite on Cold Ischemia-Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Wei Li

    2012-01-01

    Full Text Available Liver ischemia-reperfusion injury is a major cause of primary graft non-function or initial function failure post-transplantation. In this study, we examined the effects of sodium nitrite supplementation on liver IRI in either Lactated Ringer's (LR solution or University of Wisconsin (UW solution. The syngeneic recipients of liver grafts were also treated with or without nitrite by intra-peritoneal injection. Liver AST and LDH release were significantly reduced in both nitrite-supplemented LR and UW preservation solutions compared to their controls. The protective effect of nitrite was more efficacious with longer cold preservation times. Liver histological examination demonstrated better preserved morphology and architecture with nitrite treatment. Hepatocellular apoptosis was significantly reduced in the nitrite-treated livers compared their controls. Moreover, liver grafts with extended cold preservation time of 12 to 24 hours demonstrated improved liver tissue histology and function post-reperfusion with either the nitrite-supplemented preservation solution or in nitrite-treated recipients. Interestingly, combined treatment of both the liver graft and recipient did not confer protection. Thus, nitrite treatment affords significant protection from cold ischemic and reperfusion injury to donor livers and improves liver graft acute function post-transplantation. The results from this study further support the potential for nitrite therapy to mitigate ischemia-reperfusion injury in solid organ transplantation.

  8. Nitrite and nitrate concentrations and metabolism in breast milk, infant formula, and parenteral nutrition.

    Science.gov (United States)

    Jones, Jesica A; Ninnis, Janet R; Hopper, Andrew O; Ibrahim, Yomna; Merritt, T Allen; Wan, Kim-Wah; Power, Gordon G; Blood, Arlin B

    2014-09-01

    Dietary nitrate and nitrite are sources of gastric NO, which modulates blood flow, mucus production, and microbial flora. However, the intake and importance of these anions in infants is largely unknown. Nitrate and nitrite levels were measured in breast milk of mothers of preterm and term infants, infant formulas, and parenteral nutrition. Nitrite metabolism in breast milk was measured after freeze-thawing, at different temperatures, varying oxygen tensions, and after inhibition of potential nitrite-metabolizing enzymes. Nitrite concentrations averaged 0.07 ± 0.01 μM in milk of mothers of preterm infants, less than that of term infants (0.13 ± 0.02 μM) (P parenteral nutrition were equivalent to or lower than those of breast milk. Freeze-thawing decreased nitrite concentration ~64%, falling with a half-life of 32 minutes at 37°C. The disappearance of nitrite was oxygen-dependent and prevented by ferricyanide and 3 inhibitors of lactoperoxidase. Nitrite concentrations in breast milk decrease with storage and freeze-thawing, a decline likely mediated by lactoperoxidase. Compared to adults, infants ingest relatively little nitrite and nitrate, which may be of importance in the modulation of blood flow and the bacterial flora of the infant GI tract, especially given the protective effects of swallowed nitrite. © 2013 American Society for Parenteral and Enteral Nutrition.

  9. Characterizing soil erosion potential using electrical resistivity imaging : final report.

    Science.gov (United States)

    2017-04-01

    The erosion rate, or erodibility, of soil depends on many soil characteristics including: plasticity, : water content, grain size, percent clay, compaction, and shear strength. Many of these characteristics also : influence soil in situ bulk electric...

  10. Characterizing soil erosion potential using electrical resistivity imaging : technical summary.

    Science.gov (United States)

    2017-04-01

    The erosion rate, or erodibility, of soil depends on many soil characteristics : including: plasticity, water content, grain size, percent clay, compaction, and shear : strength. Many of these characteristics also influence soil in situ bulk electric...

  11. Molecular Characterization of Lactobacillus plantarum DMDL 9010, a Strain with Efficient Nitrite Degradation Capacity

    OpenAIRE

    Yong-tao Fei; Dong-mei Liu; Tong-hui Luo; Gu Chen; Hui Wu; Li Li; Yi-gang Yu

    2014-01-01

    Nitrites commonly found in food, especially in fermented vegetables, are potential carcinogens. Therefore, limiting nitrites in food is critically important for food safety. A Lactobacillus strain (Lactobacillus sp. DMDL 9010) was previously isolated from fermented vegetables by our group, and is not yet fully characterized. A number of phenotypical and genotypical approaches were employed to characterize Lactobacillus sp. DMDL 9010. Its nitrite degradation capacity was compared with four oth...

  12. Nitrite and Nitrate Concentrations and Metabolism in Breast Milk, Infant Formula, and Parenteral Nutrition

    OpenAIRE

    Jones, Jesica A.; Ninnis, Janet R.; Hopper, Andrew O.; Ibrahim, Yomna; Merritt, T. Allen; Wan, Kim-Wah; Power, Gordon G.; Blood, Arlin B.

    2013-01-01

    Dietary nitrate and nitrite are sources of gastric NO, which modulates blood flow, mucus production, and microbial flora. However, the intake and importance of these anions in infants is largely unknown. Nitrate and nitrite levels were measured in breast milk of mothers of preterm and term infants, infant formulas, and parenteral nutrition. Nitrite metabolism in breast milk was measured after freeze-thawing, at different temperatures, varying oxygen tensions, and after inhibition of potential...

  13. ADVANCED TECHNOLOGY WASTEWATER TREATMENT OF NITRITE IONS

    Directory of Open Access Journals (Sweden)

    E.G. Morozov

    2012-06-01

    Full Text Available The main reason for high concentration of nitrite ions in water is the existence of sources of industrial and agricultural pollution. Contamination of drinking water, juices, wine and other liquids of nitrite ions as a result of improper use of nitrogen fertilizers has an adverse effect on living organism, because under the influence of enzymes nitrite ions in living organisms form high carcinogenic nitrosamines, and the interaction of nitrite ions from blood hemoglobin causes such toxicity that leads to disease cyanosis [1]. Therefore removal of nitrite ions from water has received increased attention. The paper discusses an innovative wastewater treatment technology from the nitrite ion with hypochlorite produced during electrolysis.

  14. Pseudoazurin-nitrite reductase interactions.

    Science.gov (United States)

    Impagliazzo, Antonietta; Krippahl, Ludwig; Ubbink, Marcellus

    2005-09-01

    The nitrite reductase-binding site on pseudoazurin has been determined by using NMR chemical-shift perturbations. It comprises residues in the hydrophobic patch surrounding the exposed copper ligand His81 as well as several positively charged residues. The binding site is similar for both redox states of pseudoazurin, despite differences in the binding mode. The results suggest that pseudoazurin binds in a well-defined orientation. Docking simulations provide a putative structure of the complex with a binding site on nitrite reductase that has several hydrophobic and polar residues as well as a ridge of negatively charged side chains and a copper-to-copper distance of 14 A.

  15. LLWR techniques for quantifying potential soil compaction consequences of crop

    Science.gov (United States)

    Harvesting crop residues for bioenergy or bio-product production may decrease soil organic matter (SOM), resulting in the degradation of soil physical properties and ultimately soil productivity. Using the Least Limiting Water Range (LLWR) to evaluate improvement or degradation of soil physical pro...

  16. Bioprospecting Potential of the Soil Metagenome: Novel Enzymes and Bioactivities

    OpenAIRE

    Myung Hwan Lee; Seon-Woo Lee

    2013-01-01

    The microbial diversity in soil ecosystems is higher than in any other microbial ecosystem. The majority of soil microorganisms has not been characterized, because the dominant members have not been readily culturable on standard cultivation media; therefore, the soil ecosystem is a great reservoir for the discovery of novel microbial enzymes and bioactivities. The soil metagenome, the collective microbial genome, could be cloned and sequenced directly from soils to search for novel microbial...

  17. A novel marine nitrite-oxidizing

    NARCIS (Netherlands)

    Haaijer, S.C.M.; Ji, K.; van Niftrik, L.; Hoischen, A.; Speth, D.R.; Jetten, M.S.M.; Sinninghe Damsté, J.S.; Op den Camp, H.J.M.

    2013-01-01

    Marine microorganisms are important for the global nitrogen cycle, but marine nitrifiers, especially aerobic nitrite oxidizers, remain largely unexplored. To increase the number of cultured representatives of marine nitrite-oxidizing bacteria (NOB), a bioreactor cultivation approach was adopted to

  18. Interactions between ammonia and nitrite oxidizing bacteria in co-cultures: Is there evidence for mutualism, commensalism, or competition?

    Energy Technology Data Exchange (ETDEWEB)

    Sayavedra-Soto, Luis [Oregon State Univ., Corvallis, OR (United States); Arp, Daniel [Oregon State Univ., Corvallis, OR (United States)

    2017-08-01

    Nitrification is a two-step environmental microbial process in the nitrogen cycle in which ammonia is oxidized to nitrate. Ammonia-oxidizing bacteria and archaea oxidize ammonia to nitrite and nitrite is oxidized to nitrate by nitrite-oxidizing bacteria. These microorganisms, which likely act in concert in a microbial community, play critical roles in the movement of inorganic N in soils, sediments and waters and are essential to the balance of the nitrogen cycle. Anthropogenic activity has altered the balance of the nitrogen cycle through agriculture practices and organic waste byproducts. Through their influence on available N for plant growth, nitrifying microorganisms influence plant productivity for food and fiber production and the associated carbon sequestration. N Fertilizer production, primarily as ammonia, requires large inputs of natural gas and hydrogen. In croplands fertilized with ammonia-based fertilizers, nitrifiers contribute to the mobilization of this N by producing nitrate (NO3-), wasting the energy used in the production and application of ammonia-based fertilizer. The resulting nitrate is readily leached from these soils, oxidized to gaseous N oxides (greenhouse gases), and denitrified to N2 (which is no longer available as a plant N source). Still, ammonia oxidizers are beneficial in the treatment of wastewater and they also show potential to contribute to microbial bioremediation strategies for clean up of environments contaminated with chlorinated hydrocarbons. Mitigation of the negative effects and exploitation of the beneficial effects of nitrifiers will be facilitated by a systems-level understanding of the interactions of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria with the environment and with each other.

  19. A study on the correlation between soil radon potential and average indoor radon potential in Canadian cities.

    Science.gov (United States)

    Chen, Jing; Ford, Ken L

    2017-01-01

    Exposure to indoor radon is identified as the main source of natural radiation exposure to the population. Since radon in homes originates mainly from soil gas radon, it is of public interest to study the correlation between radon in soil and radon indoors in different geographic locations. From 2007 to 2010, a total of 1070 sites were surveyed for soil gas radon and soil permeability. Among the sites surveyed, 430 sites were in 14 cities where indoor radon information is available from residential radon and thoron surveys conducted in recent years. It is observed that indoor radon potential (percentage of homes above 200 Bq m(-3); range from 1.5% to 42%) correlates reasonably well with soil radon potential (SRP: an index proportional to soil gas radon concentration and soil permeability; average SRP ranged from 8 to 26). In five cities where in-situ soil permeability was measured at more than 20 sites, a strong correlation (R(2) = 0.68 for linear regression and R(2) = 0.81 for non-linear regression) was observed between indoor radon potential and soil radon potential. This summary report shows that soil gas radon measurement is a practical and useful predictor of indoor radon potential in a geographic area, and may be useful for making decisions around prioritizing activities to manage population exposure and future land-use planning. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  20. 21 CFR 573.700 - Sodium nitrite.

    Science.gov (United States)

    2010-04-01

    ... Listing § 573.700 Sodium nitrite. Sodium nitrite may be safely used in canned pet food containing meat and... as a preservative and color fixative in canned pet food containing fish, meat, and fish and meat... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium nitrite. 573.700 Section 573.700 Food and...

  1. The soil management assessment framework: A potential soil health assessment tool

    Science.gov (United States)

    The Soil Management Assessment Framework (SMAF) was developed in the 1990s utilizing Systems Engineering and Ecology experiences with scoring functions to normalize disparate soil physical, chemical, and biological indicator data representing critical properties and processes associated with soil qu...

  2. Sodium nitrite blocks the activity of aminoglycosides against Pseudomonas aeruginosa biofilms.

    Science.gov (United States)

    Zemke, Anna C; Gladwin, Mark T; Bomberger, Jennifer M

    2015-01-01

    Sodium nitrite has broad antimicrobial activity at pH 6.5, including the ability to prevent biofilm growth by Pseudomonas aeruginosa on the surfaces of airway epithelial cells. Because of its antimicrobial activity, nitrite is being investigated as an inhaled agent for chronic P. aeruginosa airway infections in cystic fibrosis patients. However, the interaction between nitrite and commonly used aminoglycosides is unknown. This paper investigates the interaction between nitrite and tobramycin in liquid culture, abiotic biofilms, and a biotic biofilm model simulating the conditions in the cystic fibrosis airway. The addition of nitrite prevented killing by aminoglycosides in liquid culture, with dose dependence between 1.5 and 15 mM. The effect was not blocked by the nitric oxide scavenger CPTIO or dependent on efflux pump activity. Nitrite shifted the biofilm minimal bactericidal concentration (MBC-biofilm) from 256 μg/ml to >1,024 μg/ml in an abiotic biofilm model. In a biotic biofilm model, the addition of 50 mM nitrite decreased the antibiofilm activity of tobramycin by up to 1.2 log. Respiratory chain inhibition recapitulated the inhibition of aminoglycoside activity by nitrite, suggesting a potential mechanism of inhibition of energy-dependent aminoglycoside uptake. In summary, sodium nitrite induces resistance to both gentamicin and tobramycin in P. aeruginosa grown in liquid culture, as an abiotic biofilm, or as a biotic biofilm. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  3. 21 CFR 250.100 - Amyl nitrite inhalant as a prescription drug for human use.

    Science.gov (United States)

    2010-04-01

    ... August 25, 1967 (32 FR 12404), the Commissioner of Food and Drugs received reports of the abuse of this... Board, that amyl nitrite inhalant is a drug with a potentiality for harmful effect and that it should be... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Amyl nitrite inhalant as a prescription drug for...

  4. Bioavailability of sodium nitrite from an aqueous solution in healthy adults.

    NARCIS (Netherlands)

    Hunault, C.C.; van Velzen, A.G.; Sips, A.J.; Schothorst, R.C.; Meulenbelt, J.|info:eu-repo/dai/nl/079479227

    2009-01-01

    Nitrate intake in humans is high through intake of vegetables such as beets, lettuce, and spinach. Nitrate itself is a compound of low toxicity but its metabolite, nitrite, formed by bacteria in the oral cavity and gastrointestinal tract, has been suspected of potential carcinogenic effects. Nitrite

  5. Potential enzyme activities in cryoturbated organic matter of arctic soils

    Science.gov (United States)

    Schnecker, J.; Wild, B.; Rusalimova, O.; Mikutta, R.; Guggenberger, G.; Richter, A.

    2012-12-01

    An estimated 581 Gt organic carbon is stored in arctic soils that are affected by cryoturbtion, more than in today's atmosphere (450 Gt). The high amount of organic carbon is, amongst other factors, due to topsoil organic matter (OM) that has been subducted by freeze-thaw processes. This cryoturbated OM is usually hundreds to thousands of years old, while the chemical composition remains largely unaltered. It has therefore been suggested, that the retarded decomposition rates cannot be explained by unfavourable abiotic conditions in deeper soil layers alone. Since decomposition of soil organic material is dependent on extracellular enzymes, we measured potential and actual extracellular enzyme activities in organic topsoil, mineral subsoil and cryoturbated material from three different tundra sites, in Zackenberg (Greenland) and Cherskii (North-East Siberia). In addition we analysed the microbial community structure by PLFAs. Hydrolytic enzyme activities, calculated on a per gram dry mass basis, were higher in organic topsoil horizons than in cryoturbated horizons, which in turn were higher than in mineral horizons. When calculated on per gram carbon basis, the activity of the carbon acquiring enzyme exoglucanase was not significantly different between cryoturbated and topsoil organic horizons in any of the three sites. Oxidative enzymes, i.e. phenoloxidase and peroxidase, responsible for degradation of complex organic substances, showed higher activities in topsoil organic and cryoturbated horizons than in mineral horizons, when calculated per gram dry mass. Specific activities (per g C) however were highest in mineral horizons. We also measured actual cellulase activities (by inhibiting microbial uptake of products and without substrate addition): calculated per g C, the activities were up to ten times as high in organic topsoil compared to cryoturbated and mineral horizons, the latter not being significantly different. The total amount of PLFAs, as a proxy for

  6. the potential of alginic acid and polygal for soil stabilization

    African Journals Online (AJOL)

    user

    1985-09-01

    Sep 1, 1985 ... and the changes in the engineering properties of the soils with additives admixed are discussed. The possibility of using alginic acid and polygal as ..... Soil Mechanics. McGraw Hill Univ. Series In Civ. Engineering, 1978. 18. Schofield, A.N. and Wroth, C.P.. Critical State Soil Mechanics. McGraw Hill Bk. Co.

  7. Taurine-nitrite interaction as a precursor of alkylation mechanisms.

    Science.gov (United States)

    Arenas-Valgañón, Jorge; Gómez-Bombarelli, Rafael; González-Pérez, Marina; González-Jiménez, Mario; Calle, Emilio; Casado, Julio

    2012-09-15

    Taurine (2-aminoethanesulphonic acid) is an amino acid-like-compound widely used as an ingredient in some nutraceuticals and energy drinks. Here the interaction of taurine (Tau) with nitrite was investigated. The reactions were carried out mimicking the conditions of the stomach lumen. The conclusions drawn are as follows: (i) Nitrite showed nitrosating capacity on Tau. The rate equation was ν(N)=k(obs)[Tau](o)[nitrite](o)(2), this result suggesting that the yield of nitrosation products in the human stomach would increase sharply with higher nitrate/nitrite intakes; (ii) the experimental results suggest a mechanism for the nitrosation, whose rate-limiting step is bimolecular attack by N(2)O(3); (iii) the nitrosation of taurine affords ethanesultone (ES), which displays alkylating capacity on the nucleophile 4-(p-nitrobenzyl)pyridine (NBP), a trap for alkylating agents with nucleophilic characteristics similar to those of DNA bases. Although the NBP alkylation rate for ethanesultone is much higher than those for carcinogenic four-membered ring lactones, resulting in the nitrosation of amino carboxylic acids, the fraction of ES-forming adduct with NBP is much smaller; (iv) in spite of the low risk to human health, since the stomach lumen conditions could be a favourable medium for Tau nitrosation, attention should be paid to potential situations of the concurrence of high contents of taurine and nitrite/nitrate in the diet. Copyright © 2012. Published by Elsevier Ltd.

  8. The nitrite oxidizing system of Nitrobacter winogradskyi.

    Science.gov (United States)

    Yamanaka, T; Fukumori, Y

    1988-12-01

    Cytochrome components which participate in the oxidation of nitrite in Nitrobacter winogradskyi have been highly purified and their properties studied in detail. Cytochrome a1c1 is an iron-sulphur molybdoenzyme which has haems a and c and acts as a nitrite-cytochrome c oxidoreductase. Cytochrome c-550 is homologous to eukaryotic cytochrome c and acts as the electron mediator between cytochrome a1c1 and aa3-type cytochrome c oxidase. The oxidase is composed of two kinds of subunits, has two molecules of haem a and two atoms of copper in the molecule, and oxidizes actively eukaryotic ferrocytochrome c as well as its own ferrocytochrome c-550. Further, a flavoenzyme has been obtained which has transhydrogenase activity and catalyses reduction of NADP+ with benzylviologen radical. This enzyme may be responsible for production of NADPH in N. winogradskyi. The electron transfer against redox potential from NO2- to cytochrome c could be pushed through prompt removal by cytochrome aa3 of H+ formed by the dehydrogenation of NO2- + H2O. As cytochrome c in anaerobically kept cell-free extracts is rapidly reduced on addition of NO2-, a membrane potential does not seem necessary for the reduction of cytochrome c by cytochrome a1c1 with NO2- in vivo.

  9. Citrus co-products as technological strategy to reduce residual nitrite content in meat products.

    Science.gov (United States)

    Viuda-Martos, M; Fernández-López, J; Sayas-Barbera, E; Sendra, E; Navarro, C; Pérez-Alvarez, J A

    2009-10-01

    Sodium or potassium nitrite is widely used as a curing agent in cured meat products because it inhibits outgrowth and neurotoxin formation by Clostridium botulinum, delays the development of oxidative rancidity, develops the characteristic flavor of cured meats, and reacts with myoglobin and stabilizes the red meat color. As soon as nitrite is added in the meat formulation, it starts to disappear and the nitrite that has not reacted with myoglobin and it is available corresponds to residual nitrite level. Health concerns relating to the use of nitrates and nitrites in cured meats (cooked and dry cured) trend toward decreased usage to alleviate the potential risk to the consumers from formation of carcinogenic compounds. Recently, some new ingredients principally agro-industrial co-products in general and those from the citrus industry in particular (albedo [with different treatments], dietetic fiber obtained from the whole co-product, and washing water used in the process to obtain the dietetic fiber) are seen as good sources of bio-compounds that may help to reduce the residual nitrite level in meat products. From these co-products, citrus fiber shows the highest potential to reduce the residual nitrite level, followed by the albedo and finally the washing water. The aim of this article is to describe the latest advances concerning the use of citrus co-products in meat products as a potential ingredient to reduce the nitrite level.

  10. STATEWIDE MAPPING OF FLORIDA SOIL RADON POTENTIALS VOLUME 1. TECHNICAL REPORT

    Science.gov (United States)

    The report gives results of a statewide mapping of Florida soil radon potentials. Statewide maps identify Florida Regions with different levels of soil radon potential. The maps provide scientific estimates of regional radon potentials that can serve as a basis for implementing r...

  11. STATEWIDE MAPPING OF FLORIDA SOIL RADON POTENTIALS VOLUME 2. APPENDICES A-P

    Science.gov (United States)

    The report gives results of a statewide mapping of Florida soil radon potentials. Statewide maps identify Florida Regions with different levels of soil radon potential. The maps provide scientific estimates of regional radon potentials that can serve as a basis for implementing r...

  12. Soil Parameters Drive the Structure, Diversity and Metabolic Potentials of the Bacterial Communities Across Temperate Beech Forest Soil Sequences.

    Science.gov (United States)

    Jeanbille, M; Buée, M; Bach, C; Cébron, A; Frey-Klett, P; Turpault, M P; Uroz, S

    2016-02-01

    Soil and climatic conditions as well as land cover and land management have been shown to strongly impact the structure and diversity of the soil bacterial communities. Here, we addressed under a same land cover the potential effect of the edaphic parameters on the soil bacterial communities, excluding potential confounding factors as climate. To do this, we characterized two natural soil sequences occurring in the Montiers experimental site. Spatially distant soil samples were collected below Fagus sylvatica tree stands to assess the effect of soil sequences on the edaphic parameters, as well as the structure and diversity of the bacterial communities. Soil analyses revealed that the two soil sequences were characterized by higher pH and calcium and magnesium contents in the lower plots. Metabolic assays based on Biolog Ecoplates highlighted higher intensity and richness in usable carbon substrates in the lower plots than in the middle and upper plots, although no significant differences occurred in the abundance of bacterial and fungal communities along the soil sequences as assessed using quantitative PCR. Pyrosequencing analysis of 16S ribosomal RNA (rRNA) gene amplicons revealed that Proteobacteria, Acidobacteria and Bacteroidetes were the most abundantly represented phyla. Acidobacteria, Proteobacteria and Chlamydiae were significantly enriched in the most acidic and nutrient-poor soils compared to the Bacteroidetes, which were significantly enriched in the soils presenting the higher pH and nutrient contents. Interestingly, aluminium, nitrogen, calcium, nutrient availability and pH appeared to be the best predictors of the bacterial community structures along the soil sequences.

  13. Dependence of nitrite oxidation on nitrite and oxygen in low-oxygen seawater

    Science.gov (United States)

    Sun, Xin; Ji, Qixing; Jayakumar, Amal; Ward, Bess B.

    2017-08-01

    Nitrite oxidation is an essential step in transformations of fixed nitrogen. The physiology of nitrite oxidizing bacteria (NOB) implies that the rates of nitrite oxidation should be controlled by concentration of their substrate, nitrite, and the terminal electron acceptor, oxygen. The sensitivities of nitrite oxidation to oxygen and nitrite concentrations were investigated using 15N tracer incubations in the Eastern Tropical North Pacific. Nitrite stimulated nitrite oxidation under low in situ nitrite conditions, following Michaelis-Menten kinetics, indicating that nitrite was the limiting substrate. The nitrite half-saturation constant (Ks = 0.254 ± 0.161 μM) was 1-3 orders of magnitude lower than in cultivated NOB, indicating higher affinity of marine NOB for nitrite. The highest rates of nitrite oxidation were measured in the oxygen depleted zone (ODZ), and were partially inhibited by additions of oxygen. This oxygen sensitivity suggests that ODZ specialist NOB, adapted to low-oxygen conditions, are responsible for apparently anaerobic nitrite oxidation.

  14. Leaching potential of metallic elements from contaminated soils under anoxia.

    Science.gov (United States)

    Balint, Ramona; Nechifor, Gheorghe; Ajmone-Marsan, Franco

    2014-02-01

    Understanding metallic element (ME) behaviour in soils subjected to alternating redox conditions is of significant environmental importance, particularly for contaminated soils. Although variations in the hydrological status of soils may lead to the release of ME, redox-driven changes in ME dynamics are still not sufficiently understood. We studied the effects of alternating redox cycles on the release, leaching and redistribution of Zn, Cu and Pb in metal mine-contaminated and non-contaminated soils by means of a column experiment. Although the release of Zn was promoted by the onset of reductive conditions, successive redox cycles favoured metal partitioning in less labile fractions limiting its further mobilization. The release of Cu in soil pore waters and redistribution in the solid phase towards more labile pools were strongly dependent on the alternation between oxidizing and reducing conditions. In contaminated soils, the presence of chalcopyrite could have determined the release of Cu under oxic conditions and its relative immobilization under subsequent anoxic conditions. The behaviour of Pb did not seem to be influenced by the redox status, although higher concentrations in the column leachates with respect to soil pore waters suggested that alternating redox conditions could nonetheless result in substantial mobilization. This study provides evidence that the alternation of soil redox conditions may play a more important role in determining the release and leaching of ME from soils with respect to reducing or oxidizing conditions considered separately.

  15. SOIL REDOX POTENTIAL AND ITS IMPACT ON MICROORGANISMS AND PLANTS OF WETLANDS

    Directory of Open Access Journals (Sweden)

    Ewelina Tokarz

    2015-06-01

    Full Text Available Although peatlands cover only 3% of the Earth’s surface, they constitute a huge reservoir of carbon. It is estimated that they accumulate one third of carbon contained in all types of soils worldwide. Therefore, knowledge of the physical, chemical, and biological properties of peat is important for prevention of peat degradation and release of carbon stored as CO2 into the atmosphere. In organic soils, water plays a very important role as a protective factor against mineralisation of organic matter. Therefore, organic soils are characterised by high specificity and dissimilarity from mineral soils. The hydrological factor induces a variety of changes in the physical and chemical properties, e.g. low redox potential or low oxygen content in soil pores. Many soil processes are determined by the soil oxygenation status, which can be measured with various indicators as well as direct and indirect measurements. One of the indirect methods is measurement of the redox potential. The oxidation-reduction potential (redox potential or Eh is a measure of the ratio of oxidised to reduced forms in a solution. This parameter is inextricably linked to oxygen supply and the processes of consumption thereof by microorganisms and plant roots. Therefore, the redox potential is used as an indicator of the oxygenation status and the content of biogenic forms and toxins in the soil environment and sediments. In the case of submerged soils, penetration of atmospheric oxygen into the soil is limited due to low rates of oxygen diffusion and, hence, low redox potential, which inhibits plant growth through inhibition of respiration and production of toxins in reducing conditions. The aim of this article is (1 to the show soil-plant-soil microorganism interactions taking place on peatbogs in the context of redox potential, (2 to investigate the responses of plants and soil microorganisms to the changing redox potential, and (3 to demonstrate the mechanisms of plant

  16. Dietary Nitrite: from menace to marvel

    Directory of Open Access Journals (Sweden)

    Nathan S. Bryan

    2016-11-01

    Full Text Available The health benefits of nitrite are now indisputable when administered in a clinical setting for specific diseases. Currently, most published reports identify the production of nitric oxide (NO as the mechanism of action for nitrite. Basic science, in addition to clinical studies, demonstrate that nitrite and/or nitrate cannot restore NO homeostasis as an endothelium independent source of NO that may be a redundant system for endogenous NO production. Nitrate must first be reduced to nitrite by oral commensal bacteria; nitrite can then be further reduced to NO along the physiological oxygen gradient. But despite decades of rigorous research on sodium nitrate’s safety and efficacy as a curing agent, sodium nitrite is still regarded by many as a toxic undesirable food additive. However, research within the biomedical science community has revealed enormous therapeutic benefits of nitrite which are being developed as novel therapies for conditions associated with nitric oxide insufficiency. Thus, this review will highlight the fundamental biochemistry of nitrite in human physiology and provide evidence that nitrite be considered an essential nutrient. Foods or diets enriched with nitrite can have profound positive health benefits.

  17. Nitrogen Removal over Nitrite by Aeration Control in Aerobic Granular Sludge Sequencing Batch Reactors

    Directory of Open Access Journals (Sweden)

    Samuel Lochmatter

    2014-07-01

    Full Text Available This study investigated the potential of aeration control for the achievement of N-removal over nitrite with aerobic granular sludge in sequencing batch reactors. N-removal over nitrite requires less COD, which is particularly interesting if COD is the limiting parameter for nutrient removal. The nutrient removal performances for COD, N and P have been analyzed as well as the concentration of nitrite-oxidizing bacteria in the granular sludge. Aeration phase length control combined with intermittent aeration or alternate high-low DO, has proven to be an efficient way to reduce the nitrite-oxidizing bacteria population and hence achieve N-removal over nitrite. N-removal efficiencies of up to 95% were achieved for an influent wastewater with COD:N:P ratios of 20:2.5:1. The total N-removal rate was 0.18 kgN·m−3·d−1. With N-removal over nitrate the N-removal was only 74%. At 20 °C, the nitrite-oxidizing bacteria concentration decreased by over 95% in 60 days and it was possible to switch from N-removal over nitrite to N-removal over nitrate and back again. At 15 °C, the nitrite-oxidizing bacteria concentration decreased too but less, and nitrite oxidation could not be completely suppressed. However, the combination of aeration phase length control and high-low DO was also at 15 °C successful to maintain the nitrite pathway despite the fact that the maximum growth rate of nitrite-oxidizing bacteria at temperatures below 20 °C is in general higher than the one of ammonium-oxidizing bacteria.

  18. Potential drug development candidates for human soil-transmitted helminthiases.

    Directory of Open Access Journals (Sweden)

    Piero Olliaro

    2011-06-01

    Full Text Available Few drugs are available for soil-transmitted helminthiasis (STH; the benzimidazoles albendazole and mebendazole are the only drugs being used for preventive chemotherapy as they can be given in one single dose with no weight adjustment. While generally safe and effective in reducing intensity of infection, they are contra-indicated in first-trimester pregnancy and have suboptimal efficacy against Trichuris trichiura. In addition, drug resistance is a threat. It is therefore important to find alternatives.We searched the literature and the animal health marketed products and pipeline for potential drug development candidates. Recently registered veterinary products offer advantages in that they have undergone extensive and rigorous animal testing, thus reducing the risk, cost and time to approval for human trials. For selected compounds, we retrieved and summarised publicly available information (through US Freedom of Information (FoI statements, European Public Assessment Reports (EPAR and published literature. Concomitantly, we developed a target product profile (TPP against which the products were compared.The paper summarizes the general findings including various classes of compounds, and more specific information on two veterinary anthelmintics (monepantel, emodepside and nitazoxanide, an antiprotozoal drug, compiled from the EMA EPAR and FDA registration files.Few of the compounds already approved for use in human or animal medicine qualify for development track decision. Fast-tracking to approval for human studies may be possible for veterinary compounds like emodepside and monepantel, but additional information remains to be acquired before an informed decision can be made.

  19. Potentials and drawbacks of chelate-enhanced phytoremediation of soils

    NARCIS (Netherlands)

    Römkens, P.F.A.M.; Bouwman, L.A.; Japenga, J.; Draaisma, C.

    2002-01-01

    Chelate-enhanced phytoremediation has been proposed as an effective tool for the extraction of heavy metals from soils by plants. However, side-effects related to the addition of chelates, e.g. metal leaching and effects on soil micro-organisms, were usually neglected. Therefore, greenhouse and

  20. Ipomea asarifolia (Desr), A Potential Cover Crop for Soil Fertility ...

    African Journals Online (AJOL)

    *1A.A. Abdullahi, 2S.A. Ibrahim, 1S. Yusuf, 1M. Audu, 3N. Abdu, 1S.S. Noma and 4H. Shuaibu. 1Department of Soil Science and Agricultural Engineering, Usmanu Danfodiyo University, Sokoto, Nigeria. 2Crop Production Programme, Abubakar Tafawa Balewa University, Bauchi, Nigeria. 3Soil Sceince Department, Ahmadu ...

  1. The potential role of agroforestry in maintaining soil fertility on ...

    African Journals Online (AJOL)

    Despite legislation curtailing their use, they are being used for grazing, and crop and vegetable production. The soils in the cultivated dambos suffer from major phosphorus and sulphur deficiencies and have low nitrogen and organic matter content. Organic fertilizers play a significant role in maintaining soil fertility on these ...

  2. Nutritive potential of some 'edible' soils in Blantyre city, Malawi

    African Journals Online (AJOL)

    However, both the Blantyre and Indian 'edible' soils also have some traces of lead (0.05 to 0.07 .... The antibodies occur in breast milk and have a major role in mucosal ... This study attempted to assess the quality of the deep soils that are ...

  3. Carbon sequestration potential of coastal wetland soils of Veracruz, Mexico

    Science.gov (United States)

    Fuentes-Romero, Elisabeth; García-Calderón, Norma Eugenia; Ikkonen, Elena; García-Varela, Kl

    2014-05-01

    Tropical coastal wetlands, including rainforests and mangrove ecosystems play an increasingly important ecological and economic role in the tropical coastal area of the State of Veracruz /Mexico. However, soil processes in these environments, especially C-turnover rates are largely unknown until today. Therefore, we investigated CO2 and CH4 emissions together with gains and losses of organic C in the soils of two different coastal ecosystems in the "Natural Protected Area Cienaga del Fuerte (NPACF)" near Tecolutla, in the State of Veracruz. The research areas were an artificially introduced grassland (IG) and a wetland rainforest (WRF). The gas emissions from the soil surfaces were measured by a static chamber array, the soil organic C was analysed in soil profiles distributed in the two areas, humic substances were characterized and C budget was calculated. The soils in both areas acted as carbon sinks, but the soils of the WRF sequestered more C than those of the IG, which showed a higher gas emission rate and produced more dissolved organic carbon. The gas emission measurements during the dry and the rainy seasons allowed for estimating the possible influence of global warming on gas fluxes from the soils of the two different ecological systems, which show in the WRF a quite complex spatial emission pattern during the rainy season in contrast to a more continuous emission pattern in the IG plots

  4. Production efficiency and economic potential of different soil fertility ...

    African Journals Online (AJOL)

    This paper provides the economic evaluation of different soil fertility replenishing technologies (use of inorganic fertilizers, organic manure, and rhizobium inoculant) that were tested during field studies and recommended to groundnut farmers. Data on soil fertility technologies used by households, groundnut yields, and ...

  5. Topographic variability influences the carbon sequestration potential of arable soils

    DEFF Research Database (Denmark)

    Chirinda, Ngoni; Elsgaard, Lars; Thomsen, Ingrid Kaag

    2012-01-01

    There is presently limited knowledge on the influence of field spatial variability on the carbon (C) sink-source relationships in arable landscapes. This is accompanied by the fact that our understanding of soil profile C dynamics is also limited. This study aimed at investigating how spatial...... variability along a short catena influences C sinksource relationships and temporal dynamics of CO2 concentrations in soils. In spring 2011, soil samples were collected from topsoil (2-5.5 cm) and subsoil (38-41.5 cm) horizons at upslope and footslope positions in a Danish winter wheat field on a sandy loam...... soil developed on glacial till. Bulk densities and C concentrations of the soils were characterized. From June 2011, gas samples were collected at least bimonthly from the same slope positions in four spatial replicates using stainless steel needles that were permanently installed at 5, 10, 20 and 30...

  6. Effect of land use land cover change on soil erosion potential in an agricultural watershed.

    Science.gov (United States)

    Sharma, Arabinda; Tiwari, Kamlesh N; Bhadoria, P B S

    2011-02-01

    Universal soil loss equation (USLE) was used in conjunction with a geographic information system to determine the influence of land use and land cover change (LUCC) on soil erosion potential of a reservoir catchment during the period 1989 to 2004. Results showed that the mean soil erosion potential of the watershed was increased slightly from 12.11 t ha(-1) year(-1) in the year 1989 to 13.21 t ha(-1) year(-1) in the year 2004. Spatial analysis revealed that the disappearance of forest patches from relatively flat areas, increased in wasteland in steep slope, and intensification of cultivation practice in relatively more erosion-prone soil were the main factors contributing toward the increased soil erosion potential of the watershed during the study period. Results indicated that transition of other land use land cover (LUC) categories to cropland was the most detrimental to watershed in terms of soil loss while forest acted as the most effective barrier to soil loss. A p value of 0.5503 obtained for two-tailed paired t test between the mean erosion potential of microwatersheds in 1989 and 2004 also indicated towards a moderate change in soil erosion potential of the watershed over the studied period. This study revealed that the spatial location of LUC parcels with respect to terrain and associated soil properties should be an important consideration in soil erosion assessment process.

  7. Bioremediation potential of diesel-contaminated Libyan soil.

    Science.gov (United States)

    Koshlaf, Eman; Shahsavari, Esmaeil; Aburto-Medina, Arturo; Taha, Mohamed; Haleyur, Nagalakshmi; Makadia, Tanvi H; Morrison, Paul D; Ball, Andrew S

    2016-11-01

    Bioremediation is a broadly applied environmentally friendly and economical treatment for the clean-up of sites contaminated by petroleum hydrocarbons. However, the application of this technology to contaminated soil in Libya has not been fully exploited. In this study, the efficacy of different bioremediation processes (necrophytoremediation using pea straw, bioaugmentation and a combination of both treatments) together with natural attenuation were assessed in diesel contaminated Libyan soils. The addition of pea straw was found to be the best bioremediation treatment for cleaning up diesel contaminated Libyan soil after 12 weeks. The greatest TPH degradation, 96.1% (18,239.6mgkg(-1)) and 95% (17,991.14mgkg(-1)) were obtained when the soil was amended with pea straw alone and in combination with a hydrocarbonoclastic consortium respectively. In contrast, natural attenuation resulted in a significantly lower TPH reduction of 76% (14,444.5mgkg(-1)). The presence of pea straw also led to a significant increased recovery of hydrocarbon degraders; 5.7log CFU g(-1) dry soil, compared to 4.4log CFUg(-1) dry soil for the untreated (natural attenuation) soil. DGGE and Illumina 16S metagenomic analyses confirm shifts in bacterial communities compared with original soil after 12 weeks incubation. In addition, metagenomic analysis showed that original soil contained hydrocarbon degraders (e.g. Pseudoxanthomonas spp. and Alcanivorax spp.). However, they require a biostimulant (in this case pea straw) to become active. This study is the first to report successful oil bioremediation with pea straw in Libya. It demonstrates the effectiveness of pea straw in enhancing bioremediation of the diesel-contaminated Libyan soil. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Bioavailability and soil-to-plant transfer factors as indicators of potentially toxic element contamination in agricultural soils

    Energy Technology Data Exchange (ETDEWEB)

    Adamo, Paola, E-mail: paola.adamo@unina.it [Dipartimento di Agraria, Università di Napoli Federico II, via Università 100, 80055 Portici (Italy); Iavazzo, Pietro [Dipartimento di Agraria, Università di Napoli Federico II, via Università 100, 80055 Portici (Italy); Albanese, Stefano [Dipartimento di Scienze della Terra, dell' Ambiente e delle Risorse, Università di Napoli Federico II, Via Mezzocannone 8, 80134 Napoli (Italy); Agrelli, Diana [Dipartimento di Agraria, Università di Napoli Federico II, via Università 100, 80055 Portici (Italy); De Vivo, Benedetto; Lima, Annamaria [Dipartimento di Scienze della Terra, dell' Ambiente e delle Risorse, Università di Napoli Federico II, Via Mezzocannone 8, 80134 Napoli (Italy)

    2014-12-01

    Soil pollution in agricultural lands poses a serious threat to food safety, and suggests the need for consolidated methods providing advisory indications for soil management and crop production. In this work, the three-step extraction procedure developed by the EU Measurement and Testing Programme and two soil-to-plant transfer factors (relative to total and bioavailable concentration of elements in soil) were applied on polluted agricultural soils from southern Italy to obtain information on the retention mechanisms of metals in soils and on their level of translocation to edible vegetables. The study was carried out in the Sarno river plain of Campania, an area affected by severe environmental degradation potentially impacting the health of those consuming locally produced vegetables. Soil samples were collected in 36 locations along the two main rivers flowing into the plain. In 11 sites, lettuce plants were collected at the normal stage of consumption. According to Italian environmental law governing residential soils, and on the basis of soil background reference values for the study area, we found diffuse pollution by Be, Sn and Tl, of geogenic origin, Cr and Cu from anthropogenic sources such as tanneries and intensive agriculture, and more limited pollution by Pb, Zn and V. It was found that metals polluting soils as a result of human activities were mainly associated to residual, oxidizable and reducible phases, relatively immobile and only potentially bioavailable to plants. By contrast, the essential elements Zn and Cu showed a tendency to become more readily mobile and bioavailable as their total content in soil increased and were more easily transported to the edible parts of lettuce than other pollutants. According to our results, current soil pollution in the studied area does not affect the proportion of metals taken up by lettuce plants and there is a limited health risk incurred. - Highlights: • Soil pollution in an intensively farmed area of

  9. Geoinformation evaluation of soil resource potential for horticulture in Krasnodar region and the Republic of Adygea

    Science.gov (United States)

    Savin, I. Yu.; Dragavtseva, I. A.; Mironenko, N. Ya.; Sergeeva, N. N.; Domozhirova, V. V.; Morenets, A. S.; Ovechkin, S. V.

    2016-04-01

    A geoinformation database for assessing soil resource potential for horticulture in Krasnodar region and Adygea has been developed. The results of geoinformation analysis indicate that only 55-60% of soils in these regions are suitable for growing horticultural crops without limitations; about 35-40% of the total soil area is unsuitable for horticultural purposes. For plum trees, the area of unsuitable soils is somewhat lower than for other horticultural crops. Geographically, the areas of soils suitable and unsuitable for horticulture are close to one another. The thickness of the loose earthy soil material, the gravel content, the degree of salinization, the soil texture, and the degree of soil hydromorphism are the major soil properties imposing considerable limitations for the development of fruit-growing industry in the studied regions. The highest portions of soils suitable for horticulture are found in Eiskii, Kushchevskii, Krylovskii, Shcherbinovskii, and Novokubanskii districts of Krasnodar region. The development of horticulture in Tuapsinskii, Slavyanskii, and Primorsko-Akhtarskii districts is limited because of the unsuitability of soils for this purpose. About 8% of the existing orchards are found on soils recognized as unsuitable for horticulture, and only about 20% of the existing orchards are found on soils suitable for fruit growing without limitations. About 70% of the existing fruit orchards are located on degraded soils or on soils with certain limitations for horticulture. The profitability of fruit orchards on such soils is lower than that of the orchards planted on soils without limitations for horticulture. This information is necessary for the adequate economic evaluation of the degree of soil degradation.

  10. Spectrophotometric and kinetic study of nitrite and formate oxidation in Nitrobacter winogradskyi.

    Science.gov (United States)

    Van Gool, A; Laudelout, H

    1967-01-01

    The reduction levels of cytochrome c and a(1) in intact Nitrobacter cells and cell-free extracts, during and after nitrite or formate oxidation, were examined in combination with the amperometric measurement of oxygen uptake. Quite different reduction patterns were observed when comparing nitrite oxidation by intact cells and cell-free extracts. An inverse relationship was observed between the rate of electron flow and the steady-state reduction level of cytochrome a(1). Parallel observations on nitrite oxidation, by use of formate and reduced nicotinamide adenine dinucleotide as electron donors, showed the influence of the high oxidation-reduction potential of the nitrite-nitrate system on cytochrome reduction. A value for the apparent activation energy of the overall nitrite oxidation process, amounting to 15 kcal, was found in a study of the temperature dependence of cytochrome reduction.

  11. Nitrite in hamburgers in Arak, Iran.

    Science.gov (United States)

    Rezaei, Mohammad; Shariatifar, Nabi; Jahed Khaniki, Gholamreza; Javadzadeh, Morteza

    2013-01-01

    Nitrite and nitrate are used as additives in meat products to provide colour, taste and protection against micro-organisms, but excessive use of these substances can be toxic and can cause carcinogenesis in man. Natural and organic foods are not permitted to use chemical preservatives, the traditional curing agents used for cured meats, and so nitrate and/or nitrite cannot be added to hamburgers. This study aimed to measure nitrite in hamburgers sold in Arak city, in the centre of Iran, in 2011. For this purpose, 105 samples were randomly selected and analysed according to Official AOAC Method 973. The residual nitrite in the samples was 30-100 mg/kg (p < 0.001). In 85.7% of the samples, presence of nitrite was demonstrated, which suggests unfavourable production conditions and poor sodium nitrite standards at hamburger factories.

  12. Dietary nitrite attenuates oxidative stress and activates antioxidant genes in rat heart during hypobaric hypoxia.

    Science.gov (United States)

    Singh, Manjulata; Arya, Aditya; Kumar, Rajesh; Bhargava, Kalpana; Sethy, Niroj Kumar

    2012-01-01

    The nitrite anion represents the circulatory and tissue storage form of nitric oxide (NO) and a signaling molecule, capable of conferring cardioprotection and many other health benefits. However, molecular mechanisms for observed cardioprotective properties of nitrite remain largely unknown. We have evaluated the NO-like bioactivity and cardioprotective efficacies of sodium nitrite supplemented in drinking water in rats exposed to short-term chronic hypobaric hypoxia. We observed that, nitrite significantly attenuates hypoxia-induced oxidative stress, modulates HIF-1α stability and promotes NO-cGMP signaling in hypoxic heart. To elucidate potential downstream targets of nitrite during hypoxia, we performed a microarray analysis of nitrite supplemented hypoxic hearts and compared with both hypoxic and nitrite supplemented normoxic hearts respectively. The analysis revealed a significant increase in the expression of many antioxidant genes, transcription factors and cardioprotective signaling pathways which was subsequently confirmed by qRT-PCR and Western blotting. Conversely, hypoxia exposure increased oxidative stress, activated inflammatory cytokines, downregulated ion channels and altered expression of both pro- and anti-oxidant genes. Our results illustrate the physiological function of nitrite as an eNOS-independent source of NO in heart profoundly modulating the oxidative status and cardiac transcriptome during hypoxia. Copyright © 2011 Elsevier Inc. All rights reserved.

  13. Remediation of nitrite contamination in ground and surface waters using aquatic macrophytes.

    Science.gov (United States)

    Rawat, S K; Singh, R K; Singh, Rana P

    2012-01-01

    The study was carried out to determine the seasonal variation of nitrite levels in drinking and surface waters of urban, peri-urban and rural areas of Lucknow, during 2007-2008, and to evaluate the nitrite removal and accumulation potential of certain native aquatic macrophytes. Most of the drinking and surface water samples were collected from urbanized region of the city. All drinking water samples detected, showed higher nitrite level in winter, when compared with that in summer and rainy seasons. However, in drinking water samples nitrite level was below the permissible limit i.e. 3.29 mg l(-1) NO2. The surface water showed more than 3 fold higher levels of nitrite over the permissible level i.e. 0.06 mg l(-1), and the level was higher during rainy season than in summer and winterseasons. Eight macrophytes viz. Peltandra virginica, Utricularia vulgaris, Eichhomia crassipes, Trapa natans, Mimulus glabratus, Marsilea quadrifolia, Pistia stratiotes and Polygonum persicaria were studied for phytoremediation potential of nitrite from the water under simulated laboratory conditions. The gradual diminution in the level of nitrite in the water and simultaneously it's increase in the plant tissues was recorded at 5th, 10th and 15th d after plant culture. All the plants selected, removed nitrite from water but Polygonum persicaria, Mimulus glabratus, Trapa natans and Pistia stratiotes were found more efficient and removed nitrite upto 60.91, 58.09, 60.97 and 72.28%, respectively. Observations revealed that Pistia stratiotes can be used forthe effective removal of nitrite from the contaminated water.

  14. Soil magnetic susceptibility and contamination of soils from kindergartens areas by potentially toxic elements in Bratislava (Slovakia)

    OpenAIRE

    Ondrej Ďurža; Edgar Hiller; Lucia Lachká; Roman Tóth

    2013-01-01

    The aims of this study were to verify the utilization of magnetic susceptibility measurements for the determination of contamination by potentially toxic elements (PTEs) of urban soils in kindergartens in the capital city of Slovakia, Bratislava, and to determine the concentrations of selected PTEs like As, Cd, Cu, Hg, Pb and Zn in the soils. The results showed that the urban soils were contaminated mainly by Pb, Zn, Hg, and Cu with the concentrations between 11–183 mg·kg-1, 33–551 mg·kg-1, 0...

  15. Evaluation of scour potential of cohesive soils - phase 2.

    Science.gov (United States)

    2015-01-01

    Determination of erosion parameters in order to predict scour depth is imperative to designing safe, : economic, and efficient bridge foundations. Scour behavior of granular soils is generally understood, : and design criteria have been established b...

  16. Potential and limitations of using soil mapping information to understand landscape hydrology

    Directory of Open Access Journals (Sweden)

    F. Terribile

    2011-12-01

    Full Text Available This paper addresses the following points: how can whole soil data from normally available soil mapping databases (both conventional and those integrated by digital soil mapping procedures be usefully employed in hydrology? Answering this question requires a detailed knowledge of the quality and quantity of information embedded in and behind a soil map.

    To this end a description of the process of drafting soil maps was prepared (which is included in Appendix A of this paper. Then a detailed screening of content and availability of soil maps and database was performed, with the objective of an analytical evaluation of the potential and the limitations of soil data obtained through soil surveys and soil mapping. Then we reclassified the soil features according to their direct, indirect or low hydrologic relevance. During this phase, we also included information regarding whether this data was obtained by qualitative, semi-quantitative or quantitative methods. The analysis was performed according to two main points of concern: (i the hydrological interpretation of the soil data and (ii the quality of the estimate or measurement of the soil feature.

    The interaction between pedology and hydrology processes representation was developed through the following Italian case studies with different hydropedological inputs: (i comparative land evaluation models, by means of an exhaustive itinerary from simple to complex modelling applications depending on soil data availability, (ii mapping of soil hydrological behaviour for irrigation management at the district scale, where the main hydropedological input was the application of calibrated pedo-transfer functions and the Hydrological Function Unit concept, and (iii flood event simulation in an ungauged basin, with the functional aggregation of different soil units for a simplified soil pattern.

    In conclusion, we show that special care is required in handling data from soil

  17. Spatial and temporal distribution of nitrite-dependent anaerobic methane-oxidizing bacteria in an intertidal zone of the East China Sea.

    Science.gov (United States)

    Wang, Jiaqi; Shen, Lidong; He, Zhanfei; Hu, Jiajie; Cai, Zhaoyang; Zheng, Ping; Hu, Baolan

    2017-11-01

    Nitrite-dependent anaerobic methane oxidation (N-DAMO), which couples anaerobic methane oxidation and nitrite reduction, is a recently discovered bioprocess coupling microbial nitrogen and carbon cycles. The discovery of this microbial process challenges the traditional knowledge of global methane sinks and nitrogen losses. In this study, the abundance and activity of N-DAMO bacteria were investigated and their contributions to methane sink and nitrogen loss were estimated in different seasons and different partitions of an intertidal zone of the East China Sea. The results showed that N-DAMO bacteria were extensively and continuously present in the intertidal zone, with the number of cells ranging from 5.5 × 104 to 2.8 × 105 copy g-1 soil and the potential activity ranging from 0.52 to 5.7 nmol CO2 g-1 soil day-1, contributing 5.0-36.6% of nitrite- and sulfate-dependent anaerobic methane oxidation in the intertidal zone. The N-DAMO activity and its contribution to the methane consumption were highest in the spring and in the low intertidal zone. These findings showed that the N-DAMO process is an important methane and nitrogen sink in the intertidal zone and varies with the seasons and the partitions of the intertidal zone.

  18. Soil microbial communities alter leaf chemistry and influence allelopathic potential among coexisting plant species.

    Science.gov (United States)

    Meiners, Scott J; Phipps, Kelsey K; Pendergast, Thomas H; Canam, Thomas; Carson, Walter P

    2017-04-01

    While both plant-soil feedbacks and allelochemical interactions are key drivers of plant community dynamics, the potential for these two drivers to interact with each other remains largely unexplored. If soil microbes influence allelochemical production, this would represent a novel dimension of heterogeneity in plant-soil feedbacks. To explore the linkage between soil microbial communities and plant chemistry, we experimentally generated soil microbial communities and evaluated their impact on leaf chemical composition and allelopathic potential. Four native perennial old-field species (two each of Aster and Solidago) were grown in pairwise combination with each species' soil microbial community as well as a sterilized inoculum. We demonstrated unequivocally that variation in soil microbial communities altered leaf chemical fingerprints for all focal plant species and also changed their allelopathic potential. Soil microbes reduced allelopathic potential in bioassays by increasing germination 25-54% relative to sterile control soils in all four species. Plants grown with their own microbial communities had the lowest allelopathic potential, suggesting that allelochemical production may be lessened when growing with microbes from conspecifics. The allelopathic potential of plants grown in congener and confamilial soils was indistinguishable from each other, indicating an equivalent response to all non-conspecific microbial communities within these closely related genera. Our results clearly demonstrated that soil microbial communities cause changes in leaf tissue chemistry that altered their allelopathic properties. These findings represent a new mechanism of plant-soil feedbacks that may structure perennial plant communities over very small spatial scales that must be explored in much more detail.

  19. Inhibitory effects of nitrite on the reactions of bovine carbonic anhydrase II with CO2 and bicarbonate consistent with zinc-bound nitrite.

    Science.gov (United States)

    Nielsen, Per M; Fago, Angela

    2015-08-01

    Carbonic anhydrase (CA) is a zinc enzyme that catalyzes hydration of carbon dioxide (CO2) and dehydration of bicarbonate in red blood cells, thus facilitating CO2 transport and excretion. Bovine CA II may also react with nitrite to generate nitric oxide, although nitrite is a known inhibitor of the CO2 hydration reaction. To address the potential in vivo interference of these reactions and the nature of nitrite binding to the enzyme, we here investigate the inhibitory effect of 10-30 mM nitrite on Michaelis-Menten kinetics of CO2 hydration and bicarbonate dehydration by stopped-flow spectroscopy. Our data show that nitrite significantly affects the apparent dissociation constant KM for CO2 (11 mM) and bicarbonate (221 mM), and the turnover number kcat for the CO2 hydration (1.467 × 10(6) s(-1)) but not for the bicarbonate dehydration (7.927 × 10(5) s(-1)). These effects demonstrate mixed and competitive inhibition for the reaction with CO2 and bicarbonate, respectively, and are consistent with nitrite binding to the active site zinc. The high apparent dissociation constant found here for CO2, bicarbonate and nitrite (16-120 mM) are all overall consistent with published data and reveal a large capacity of free enzyme available for binding each of the three substrates at their in vivo levels, with little or no significant interference among reactions. The low affinity of the enzyme for nitrite suggests that the in vivo interaction between red blood cell CA II and nitrite requires compartmentalization at the anion exchanger protein of the red cell membrane to be physiologically relevant. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Protozoan predation in soil slurries compromises determination of contaminant mineralization potential.

    Science.gov (United States)

    Badawi, Nora; Johnsen, Anders R; Brandt, Kristian K; Sørensen, Jan; Aamand, Jens

    2012-11-01

    Soil suspensions (slurries) are commonly used to estimate the potential of soil microbial communities to mineralize organic contaminants. The preparation of soil slurries disrupts soil structure, however, potentially affecting both the bacterial populations and their protozoan predators. We studied the importance of this "slurry effect" on mineralization of the herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA, (14)C-labelled), focussing on the effects of protozoan predation. Mineralization of MCPA was studied in "intact" soil and soil slurries differing in soil:water ratio, both in the presence and absence of the protozoan activity inhibitor cycloheximide. Protozoan predation inhibited mineralization in dense slurry of subsoil (soil:water ratio 1:3), but only in the most dilute slurry of topsoil (soil:water ratio 1:100). Our results demonstrate that protozoan predation in soil slurries may compromise quantification of contaminant mineralization potential, especially when the initial density of degrader bacteria is low and their growth is controlled by predation during the incubation period. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Plant effects on soil denitrification - a review of potential mechanisms

    Science.gov (United States)

    Malique, Francois; Butterbach-Bahl, Klaus; Dannenmann, Michael

    2017-04-01

    Denitrification is a microbial process occurring in soils, both producing and consuming the potent greenhouse gas nitrous oxide (NO), competing for nitrate with plants and hydrological leaching pathways, removing nutrients and reactive nitrogen from the biosphere, and closing the global nitrogen cycle. Despite its obvious importance, denitrification remained among the least well quantified biogeochemical processes in soils. This is due to enormous methodological difficulties involved in the direct quantification of soil microbial denitrification rates (mainly with regard to the terminal product N2) and the denitrification nitrogen gas product ratios (NO:N2O:N2), Plants may affect denitrification through a myriad of mechanisms such as e.g., competition for nitrate and water, through oxygen consumption, by regulating litter quality and changing soil pH, and via the exudation of labile carbon or secondary plant compounds involved in shaping the rhizospheric microbial community. However, plant effects on denitrification so far hardly were quantified so that the actual extent of plant control on denitrification is largely unknown. Here, we summarize the current knowledge on mechanisms how plants can affect denitrification rates and N gas product ratios in soils at temporal scales from hours to days and years. We review earlier research to quantify plant effects on denitrification as well as critically discuss the limited methods currently available to quantify plant-soil-denitrifier interactions. Finally, we provide pointers to use plants as tools to manage denitrification, e.g. to improve N use efficiency in agricultural ecosystems and to minimize soil nitrous oxide emissions.

  2. Do soil organic carbon levels affect potential yields and nitrogen use efficiency?

    DEFF Research Database (Denmark)

    Oelofse, Myles; Markussen, Bo; Knudsen, Leif

    2015-01-01

    Soil organic carbon (SOC) is broadly recognised as an important parameter affecting soil quality, and can therefore contribute to improving a number of soil properties that influence crop yield. Previous research generally indicates that soil organic carbon has positive effects on crop yields...... draws on historical data sets from the Danish national field trials consisting of 560 winter wheat (Triticum aestivum L.) trials and 309 spring barley (Hordeum vulgare L.) trials conducted over the past 20 and 17 years, respectively. We hypothesised that for these two crops, the potential grain yield...... and aimed to elucidate the sole effect of SOC by controlling for potential confounding variables. No significant effect of SOC on potential winter wheat was found, whilst for spring barley, only for the course sandy loam soil type was a borderline significantly positive effect of SOC on potential yields...

  3. Crosstalk between nitrite, myoglobin and reactive oxygen species to regulate vasodilation under hypoxia.

    Directory of Open Access Journals (Sweden)

    Matthias Totzeck

    Full Text Available The systemic response to decreasing oxygen levels is hypoxic vasodilation. While this mechanism has been known for more than a century, the underlying cellular events have remained incompletely understood. Nitrite signaling is critically involved in vessel relaxation under hypoxia. This can be attributed to the presence of myoglobin in the vessel wall together with other potential nitrite reductases, which generate nitric oxide, one of the most potent vasodilatory signaling molecules. Questions remain relating to the precise concentration of nitrite and the exact dose-response relations between nitrite and myoglobin under hypoxia. It is furthermore unclear whether regulatory mechanisms exist which balance this interaction. Nitrite tissue levels were similar across all species investigated. We then investigated the exact fractional myoglobin desaturation in an ex vivo approach when gassing with 1% oxygen. Within a short time frame myoglobin desaturated to 58±12%. Given that myoglobin significantly contributes to nitrite reduction under hypoxia, dose-response experiments using physiological to pharmacological nitrite concentrations were conducted. Along all concentrations, abrogation of myoglobin in mice impaired vasodilation. As reactive oxygen species may counteract the vasodilatory response, we used superoxide dismutase and its mimic tempol as well as catalase and ebselen to reduce the levels of reactive oxygen species during hypoxic vasodilation. Incubation of tempol in conjunction with catalase alone and catalase/ebselen increased the vasodilatory response to nitrite. Our study shows that modest hypoxia leads to a significant nitrite-dependent vessel relaxation. This requires the presence of vascular myoglobin for both physiological and pharmacological nitrite levels. Reactive oxygen species, in turn, modulate this vasodilation response.

  4. THE POTENTIAL OF γ-RAY SPECTROSCOPY FOR SOIL PROXIMAL SURVEY IN CLAYEY SOILS

    Directory of Open Access Journals (Sweden)

    Simone Priori

    2014-01-01

    Full Text Available Gamma-ray spectroscopy surveys the intensity and distribution of γ-rays emitted from radionuclides of soils and bedrocks. The most important radionuclides of soils and rocks are: 40K, 232Th, 238U and 137Cs, the latter due to Chernobyl burst or radioactive pollution. Distribution and quantity of these radionuclides into the soil is strictly linked to parent material mineralogy and soil cation exchange capacity. The aim of this work is to show the makings of γ-ray spectroscopy proximal survey within experimental fields with clayey soils in western Sicily.The γ-ray spectrometer used for the fieldwork was “The Mole”, made by “The Soil Company”, “Medusa system” and the University of Groningen, from The Netherlands. During the survey of eight experimental fields, 55 soil samples were collected for laboratory analysis of particle size distribution, calcium carbonate, organic carbon and total nitrogen content. The results of the work showed the statistical correlations between soil features and γ-ray data. 

  5. Potential effects of vinasse as a soil amendment to control runoff and soil loss

    Science.gov (United States)

    Hazbavi, Z.; Sadeghi, S. H. R.

    2016-02-01

    Application of organic materials are well known as environmental practices in soil restoration, preserving soil organic matter and recovering degraded soils of arid and semiarid lands. Therefore, the present research focused on evaluating the effectiveness of vinasse, a byproduct mainly of the sugar-ethanol industry, on soil conservation under simulated rainfall. Vinasse can be recycled as a soil amendment due to its organic matter content. Accordingly, the laboratory experiments were conducted by using 0.25 m2 experimental plots at 20 % slope and rainfall intensity of 72 mm h-1 with 0.5 h duration. The effect of vinasse was investigated on runoff and soil loss control. Experiments were set up as a control (with no amendment) and three treated plots with doses of 0.5, 1, and 1.5 L m-2 of vinasse subjected to simulated rainfall. Laboratory results indicated that vinasse at different levels could not significantly (P > 0.05) decrease the runoff amount and soil loss rate in the study plots compared to untreated plots. The average amounts of minimum runoff volume and soil loss were about 3985 mL and 46 g for the study plot at a 1 L m-2 level of vinasse application.

  6. Evaluation of Sikora instead of SMP buffer to estimate the potential acidity of brazilian soils

    Directory of Open Access Journals (Sweden)

    Maria Alice Santanna

    2011-10-01

    Full Text Available Despite the efficiency of the Shoemaker, McLean, Pratt (SMP buffer method in estimating soil acidity, the presence of p-nitrophenol and potassium chromate in the solution, both hazardous substances, has caused increasing environmental concerns. The purpose of this study was to test Sikora method (Sikora, 2006 as an alternative to the adapted SMP buffer method, generally used to estimate potential acidity of Southern Brazilian soils. For the test, 21 soils in the South and Cerrado regions of Brazil were sampled. (1 The potential acidity values of these soils range from 35.95 to 4.02 cmol c kg-1 of soil, reflecting a wide acidity variation. The Sikora buffer does not mimic the adapted SMP buffer used in Southern Brazil, since the former has a low ability to distinguish soils with different acidity from each other, probably due to the higher buffer capacity than of the adapted SMP solution.

  7. The relationship between historical development and potentially toxic element concentrations in urban soils

    OpenAIRE

    McIlwaine, Rebekka; Doherty, Rory; Cox, Siobhan F.; Cave, Mark

    2017-01-01

    Increasing urbanisation has a direct impact on soil quality, resulting in elevated concentrations of potentially toxic elements (PTEs) in soils. This research aims to assess if soil PTE concentrations can be used as an ‘urbanisation tracer’ by investigating geogenic and anthropogenic source contributions and controls, and considering PTE enrichment across historical urban development zones. The UK cities of Belfast and Sheffield are chosen as study areas, where available shallow and deep conc...

  8. Microbial volatile fongerprints : potential use for soil / water diagnostics and correlation with traditional microbial parameters

    OpenAIRE

    Bastos, A.C.

    2007-01-01

    This project used an electronic nose (E-nose) system composed of an array of 14 non- specific conducting polymer sensors for soil and water diagnostics, based on qualitative microbial volatile production patterns. It tested the feasibility of using soil microbial volatile fingerprints for detecting and monitoring changes in microbial activity in three soils, as a response to key environmental factors such as temperature (16, 25, 37°C), water potential (-0.7, -2.8 MPa), and nutr...

  9. Potential terrestrial fate and effects on soil biota of a coal liquefaction product spill

    Energy Technology Data Exchange (ETDEWEB)

    Strayer, R.F.; Edwards, N.T.; Walton, B.T.; Charles-Shannon, V.

    1983-01-01

    Contaminated soil samples collected from the site of a coal liquefaction product spill were used to study potential fates and effects of this synthetic fuel. Simulated weathering in the laboratory caused significant changes in residual oil composition. Soil column leachates contained high phenol levels that decreased exponentially over time. Toxicity tests demonstrated that the oil-contaminated soil was phytotoxic and caused embryotoxic and teratogenic effects on eggs of the cricket Acheta domesticus.

  10. SPECTROPHOTOMETRIC DETERMINATION OF NITRITE BY ITS ...

    African Journals Online (AJOL)

    Preferred Customer

    KEY WORDS: Nitrite, Catalytic effect, Congo red, Spectrophotometry, Drinking water. INTRODUCTION ... such as high sensitivity, low detection limits, good selectivity, rapid analysis and inexpensive instrumentation. ... Determination of nitrite by its catalytic effect on oxidation of congo red with bromate. Bull. Chem. Soc.

  11. The potential of residues of furfural and biogas as calcareous soil amendments for corn seed production.

    Science.gov (United States)

    Zhao, Yunchen; Yan, Zhibin; Qin, Jiahai; Ma, Zhijun; Zhang, Youfu; Zhang, Li

    2016-04-01

    Intensive corn seed production in Northwest of China produced large amounts of furfural residues, which represents higher treatment cost and environmental issue. The broad calcareous soils in the Northwest of China exhibit low organic matter content and high pH, which led to lower fertility and lower productivity. Recycling furfural residues as soil organic and nutrient amendment might be a promising agricultural practice to calcareous soils. A 3-year field study was conducted to evaluate the effects of furfural as a soil amendment on corn seed production on calcareous soil with compared to biogas residues. Soil physical-chemical properties, soil enzyme activities, and soil heavy metal concentrations were assessed in the last year after the last application. Corn yield was determined in each year. Furfural residue amendments significantly decreased soil pH and soil bulk density. Furfural residues combined with commercial fertilizers resulted in the greater cumulative on soil organic matter, total phosphorus, available phosphorus, available potassium, and cation exchange capacity than that of biogas residue. Simultaneously, urease, invertase, catalase, and alkaline phosphatase increased even at the higher furfural application rates. Maize seed yield increased even with lower furfural residue application rates. Furfural residues resulted in lower Zn concentration and higher Cd concentration than that of biogas residues. Amendment of furfural residues led to higher soil electrical conductivity (EC) than that of biogas residues. The addition of furfural residues to maize seed production may be considered to be a good strategy for recycling the waste, converting it into a potential resource as organic amendment in arid and semi-arid calcareous soils, and may help to reduce the use of mineral chemical fertilizers in these soils. However, the impact of its application on soil health needs to be established in long-term basis.

  12. Survey the effects of dietary sodium nitrite on the histological changes of the aortic artery in the adult male rats

    Directory of Open Access Journals (Sweden)

    Saeaid Khatamsaz

    2016-05-01

    Full Text Available Background: Because of high consumption of nitrite in processed (fast foods and high level of nitrite in water, soil and ecosystem, nitrite can endanger humans health. In this study the effects of sodium nitrite on aorta was examined in adult male rats. Materials and Methods : In the present study, 30 Wistar adult male rats were randomly divided into three groups of 10, including; control group. First experimental group that received low dose of sodium nitrite (175 mg/kg.bw, second experimental group that received high dose of sodium nitrite (350 mg/kg.bw. They were examined for 60 days. The rats got sodium nitrite through drinking water. At the end of the experiment the rats were taken to the anesthesia jar and based on ether principles, they anesthetized with ether and their blood samples were collected from their hearts. Then their aorta were extracted from their bodies and the tissue sections were prepared for testing tissue changes. Features such as histological features of aorta (morphometric and morphologic features were analyzed. The samples were stained with masson trichrome and Hematoxylin- Eosin methods. The internal media layer was measured with Image tool software. Then the amount of nitrite oxide in their blood were tested. At the end results were analyzed by 17 version of SPSS software and ANOVA test was run. Results: The results of this study showed that thickness of medial layer in two experimental group that received low and high dose of sodium nitrite compared with the control group decreased (p 0.05, and the group that received of high dose of sodium nitrite showed irregular and non- uniform state in aortic media layer. Conclusion: The finding of this study indicated that consumption of sodium nitrite in long term can induce damage in artries tissue.

  13. Potentials of Calliandra calothyrsus Meissner for Improving Soil ...

    African Journals Online (AJOL)

    Farmers identified low fertility as a major problem affecting crop yield in Mbam Division, a forest-savannah transitional zone of Centre Cameroon. An experiment was therefore carried out in farmers\\' fields in Kiki village for four consecutive years in order to investigate the effect of Calliandra calothyrsus planted fallow on soil ...

  14. Allelopathic potential of sunflower (Helianthus annus L.) on soil ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-09-17

    Sep 17, 2008 ... consisting of 2 g diammonium phosphate, 1 g urea, and 1 g potash. When the plants reached the vegetative stage ... Physical and chemical properties of soil were determined by following the standard method (Nelson and ... magnesium, iron, and manganese. Nitrate-nitrogen was determined by following ...

  15. Forage yield and soil improvement potential of some annual and ...

    African Journals Online (AJOL)

    Six annual and semi-perennial legumes were evaluated for forage production and their effect on soil properties at two sites, Pokoase (transition zone) and Nyankpala (Guinea savanna zone). The common legumes evaluated at the two sites were Lablab purpureus, Desmodium distortum, Crotalaria ochroleuca, and ...

  16. Drilling fluid base oil biodegradation potential of a soil ...

    African Journals Online (AJOL)

    Staphylococcus sp. isolated from oil-contaminated soil was grown in 1% drilling fluid base oil, HDF- 2000, as a sole source of carbon and energy. The organism has strong affinity for the substrate, growing at the rate of 0.16 h-1. It uses adherence and emulsification as mechanisms for oil uptake. In a nutrient-rich marine ...

  17. Genetic Diversity of Rhizobia in Ethiopian Soils: Their Potential to ...

    African Journals Online (AJOL)

    Nitrogen is one of the most limiting nutrients to plant growth. It has to be fixed in the form of NH4 through chemical (fertilizer production) and biological (bacterial) processes (BNF) in the soil. The endosymbiotic associations of root nodule bacteria (rhizobia) with leguminous plants fix 200-500kg N ha-1 yr-1. Consequently, the ...

  18. Soil degradation in India: Challenges and potential solutions

    Science.gov (United States)

    Soil degradation in India is estimated to occur on 147 Mha of land, including 94 Mha from water erosion, 16 Mha from acidification, 14 Mha from flooding, 9 Mha from wind erosion, 6 Mha from salinity, and 7 Mha from a combination of factors. India supports 18% of the world’s human population and 15%...

  19. Effects of grain size distribution on dynamic properties and liquefaction potential of granular soils

    Science.gov (United States)

    Chang, N. Y.; Ko, H. Y.

    1982-03-01

    Research was undertaken to investigate the effects of grain-size distribution gradation on dynamic properties and on liquefaction potential of granular soils. Resonant column tests were performed to determine the dynamic shear moduli and damping ratios of granular soil samples prepared from a Denver sand. Cyclic triaxial test cells and an MTS closed-loop servo control material testing machine were used to determine liquefaction potential. Results indicate that the shear modulus of soils at small strains is strongly dependent on the uniformity coefficient. The liquefaction potential was found to be strongly affected by the mean diameter.

  20. Does pre-dawn water potential reflect conditions of equilibrium in plant and soil water status?

    Science.gov (United States)

    Sellin, Arne

    1999-02-01

    Variation in base water potential ( Ψb, a daily maximum level of plant water potential, which is presumed to correspond to the equilibrium between soil and plant water potentials) was examined in shoots of Picea abies and Vaccinium myrtillus with respect to soil (available water storage, water potential, temperature) and atmospheric (temperature, relative humidity, vapour pressure deficit) conditions. The available soil water storage (W tr) accounted for 77% of the dynamics of Ψb, while the influence of atmospheric factors became evident under high evaporative demand. Ψb was not always observable immediately before dawn, but on 30% of observation days, the recovery continued up to an hour or two after dawn. Full equilibrium between soil and plant water potentials in P. abies in northern conditions is rather improbable by dawn in summer-time, because of the shortness of the dark period and probable night-time transpiration in the case of high atmospheric vapour pressure deficit.

  1. Micro-scale water potential gradients visualized in soil around plant root tips using microbiosensors.

    Science.gov (United States)

    Herron, Patrick M; Gage, Daniel J; Cardon, Zoe G

    2010-02-01

    Water availability and movement in soil are critical determinants of resource availability to, and interactions among, members of the soil community. However, it has been impossible to observe gradients in soil water potential empirically at millimetre spatial scales. Here we describe progress towards that goal using output from two microbial biosensors, Pantoea agglomerans BRT98/pPProGreen and Pseudomonas putida KT2442/pPProGreen, engineered with a reporter system based on the osmotically sensitive proU promoter from Escherichia coli. The proU-GFP construct in both microbiosensors produced green fluorescent protein (GFP) as a function total water potential in nonsterile soil. Controlled experiments in liquid culture showed that dramatically different microbiosensor growth rates (resulting from exposure to different salts as osmolytes) did not alter the GFP output as a function of water potential in either sensor, but P. agglomerans' GFP levels at a given water potential were strongly influenced by the type of carbon (energy) source available to the microbes. In non-sterile rhizosphere soil along Zea mays L. roots, though GFP expression was quite variable, microbiosensors reported statistically significantly more negative soil water potentials as a function of axial distance from root tips, reflecting the gradient in soil water potential hypothesized to develop during transpiration.

  2. Potential microbial contamination during sampling of permafrost soil assessed by tracers

    DEFF Research Database (Denmark)

    Bang-Andreasen, Toke; Schostag, Morten Dencker; Priemé, Anders

    2017-01-01

    biomass environments. Here, we present an example of how microbial contamination from active layer soil affected analysis of the potentially active microbial community in permafrost soil. We also present the development and use of two tracers: (1) fluorescent plastic microspheres and (2) Pseudomonas...

  3. Simulation of emergence of winter wheat in response to soil temperature, water potential and planting depth

    Science.gov (United States)

    Seedling emergence is a critical stage in the establishment of dryland wheat. Soil temperature, soil water potential and planting depth are important factors influencing emergence. These factors have considerable spatio-temporal variation making it difficult to predict the timing and percentage of w...

  4. Vacant urban lot soils and their potential to support ecosystem services

    Science.gov (United States)

    AimsUrban soils are the basis of many ecosystem services in cities. Here, we examine formerly residential vacant lot soils in Cleveland, Ohio and Detroit, Michigan, USA for their potential to provide multiple ecosystem services. We examine two key contrasts: 1) differences betwee...

  5. Wastewater Irrigation Increases the Abundance of Potentially Harmful Gammaproteobacteria in Soils in Mezquital Valley, Mexico

    Science.gov (United States)

    Broszat, Melanie; Nacke, Heiko; Blasi, Ronja; Siebe, Christina; Huebner, Johannes; Daniel, Rolf

    2014-01-01

    Wastewater contains large amounts of pharmaceuticals, pathogens, and antimicrobial resistance determinants. Only a little is known about the dissemination of resistance determinants and changes in soil microbial communities affected by wastewater irrigation. Community DNAs from Mezquital Valley soils under irrigation with untreated wastewater for 0 to 100 years were analyzed by quantitative real-time PCR for the presence of sul genes, encoding resistance to sulfonamides. Amplicon sequencing of bacterial 16S rRNA genes from community DNAs from soils irrigated for 0, 8, 10, 85, and 100 years was performed and revealed a 14% increase of the relative abundance of Proteobacteria in rainy season soils and a 26.7% increase in dry season soils for soils irrigated for 100 years with wastewater. In particular, Gammaproteobacteria, including potential pathogens, such as Pseudomonas, Stenotrophomonas, and Acinetobacter spp., were found in wastewater-irrigated fields. 16S rRNA gene sequencing of 96 isolates from soils irrigated with wastewater for 100 years (48 from dry and 48 from rainy season soils) revealed that 46% were affiliated with the Gammaproteobacteria (mainly potentially pathogenic Stenotrophomonas strains) and 50% with the Bacilli, whereas all 96 isolates from rain-fed soils (48 from dry and 48 from rainy season soils) were affiliated with the Bacilli. Up to six types of antibiotic resistance were found in isolates from wastewater-irrigated soils; sulfamethoxazole resistance was the most abundant (33.3% of the isolates), followed by oxacillin resistance (21.9% of the isolates). In summary, we detected an increase of potentially harmful bacteria and a larger incidence of resistance determinants in wastewater-irrigated soils, which might result in health risks for farm workers and consumers of wastewater-irrigated crops. PMID:24951788

  6. Automation of soil flux chamber measurements: potentials and pitfalls

    Science.gov (United States)

    Görres, Carolyn-Monika; Kammann, Claudia; Ceulemans, Reinhart

    2016-03-01

    Recent technological advances have enabled the wider application of automated chambers for soil greenhouse gas (GHG) flux measurements, several of them commercially available. However, few studies addressed the challenges associated with operating these systems. In this contribution we compared two commercial soil GHG chamber systems - the LI-8100A Automated Soil CO2 Flux System and the greenhouse gas monitoring system AGPS. From April until August 2014, the two systems monitored in parallel soil respiration (SR) fluxes at a recently harvested poplar (Populus) plantation, which provided a bare field situation directly after the harvest as well as a closed canopy later on. For the bare field situation (15 April-30 June 2014), the cumulated average SR obtained from the unfiltered data sets of the LI-8100A and the AGPS were 520 and 433 g CO2 m-2 respectively. For the closed canopy phase (1 July-31 August 2014), which was characterized by a higher soil moisture content, the cumulated average SR estimates were not significantly different with 507 and 501 g CO2 m-2 for the AGPS and the LI-8100A respectively. Flux quality control and filtering did not significantly alter the results obtained by the LI-8100A, whereas the AGPS SR estimates were reduced by at least 20 %. The main reasons for the observed differences in the performance of the two systems were (i) a lower data coverage provided by the AGPS due to technical problems; (ii) incomplete headspace mixing in the AGPS chambers; (iii) lateral soil CO2 diffusion below the collars during AGPS chamber measurements; and (iv) a possible overestimation of nighttime SR fluxes by the LI-8100A. Additionally, increased root growth was observed within the LI-8100A collars but not within the AGPS collars, which might have also contributed to the observed differences. In contrast to the LI-8100A, the AGPS had the gas sample inlets installed inside the collars and not the chambers. This unique design feature enabled for the first

  7. Potential linkages between mineral magnetic measurements and urban roadside soil pollution (part 2).

    Science.gov (United States)

    Crosby, C J; Fullen, M A; Booth, C A

    2014-03-01

    Use of mineral magnetic concentration parameters (χLF, χARM and SIRM) as a potential pollution proxy for soil samples collected from Wolverhampton (UK) is explored. Comparison of soil-related analytical data by correlation analyses between each magnetic parameter and individual geochemical classes (i.e. Fe, Pb, Ni, Zn, Cd), are reported. χLF, χARM and SIRM parameters reveal significant (p soils in certain environments and/or specific settings that are appropriate for monitoring techniques. The mineral magnetic technique offers a simple, reliable, rapid, sensitive, inexpensive and non-destructive approach that could be a valuable pollution proxy for soil contamination studies.

  8. Novel genes for nitrite reductase and Amo-related proteins indicate a role of uncultivated mesophilic crenarchaeota in nitrogen cycling.

    Science.gov (United States)

    Treusch, Alexander H; Leininger, Sven; Kletzin, Arnulf; Schuster, Stephan C; Klenk, Hans-Peter; Schleper, Christa

    2005-12-01

    Mesophilic crenarchaeota are frequently found in terrestrial and marine habitats worldwide, but despite their considerable abundance the physiology of these as yet uncultivated archaea has remained unknown. From a 1.2 Gb large-insert environmental fosmid library of a calcareous grassland soil, a 43 kb genomic fragment was isolated with a ribosomal RNA that shows its affiliation to group 1.1b of crenarchaeota repeatedly found in soils. The insert encoded a homologue of a copper-containing nitrite reductase with an unusual C-terminus that encoded a potential amicyanin-like electron transfer domain as well as two proteins related to subunits of ammonia monooxygenases or particulate methane monooxygenases (AmoAB/PmoAB) respectively. Expression of nirK and the amoA-like gene was shown by reverse transcription polymerase chain reaction (PCR) analyses in soil samples, the latter being found at higher levels when the soil was incubated with ammonia (measured by quantitative PCR). Further variants of both genes were amplified from soil samples and were found in the environmental database from the Sargasso Sea plankton. Taken together, our findings suggest that mesophilic terrestrial and marine crenarchaeota might be capable of ammonia oxidation under aerobic and potentially also under anaerobic conditions.

  9. Is the inherent potential of maize roots efficient for soil phosphorus acquisition?

    Directory of Open Access Journals (Sweden)

    Yan Deng

    Full Text Available Sustainable agriculture requires improved phosphorus (P management to reduce the overreliance on P fertilization. Despite intensive research of root adaptive mechanisms for improving P acquisition, the inherent potential of roots for efficient P acquisition remains unfulfilled, especially in intensive agriculture, while current P management generally focuses on agronomic and environmental concerns. Here, we investigated how levels of soil P affect the inherent potential of maize (Zea mays L. roots to obtain P from soil. Responses of root morphology, arbuscular mycorrhizal colonization, and phosphate transporters were characterized and related to agronomic traits in pot and field experiments with soil P supply from deficiency to excess. Critical soil Olsen-P level for maize growth approximated 3.2 mg kg(-1, and the threshold indicating a significant environmental risk was about 15 mg kg(-1, which represented the lower and upper levels of soil P recommended in current P management. However, most root adaptations involved with P acquisition were triggered when soil Olsen-P was below 10 mg kg(-1, indicating a threshold for maximum root inherent potential. Therefore, to maintain efficient inherent potential of roots for P acquisition, we suggest that the target upper level of soil P in intensive agriculture should be reduced from the environmental risk threshold to the point maximizing the inherent potential of roots.

  10. The influence of land use on soil organic carbon and nitrogen content and redox potential

    DEFF Research Database (Denmark)

    Kusliene, Gedrime

    2010-01-01

    different farming systems (conventional and organic) as well as abandoned lands. We choose the plants of two botanical species (Poaceae and Fabaceae) in organic and conventional farming systems as well as abandoned lands. Experimental results show that the best soil organic matter status according...... to the investigated indexes is in the soils of conventional and orgaic farming systems occupied with mixtures of Poaceae and Fabaceae and the worst - in the soils of abandoned Poaceae meadowa. In the abandoned lands, Fabaceae (galega) had better influence on soil organic matter status than Poaceae.......The aim of the research was to evaluate organic matter status in the soil according to the organic carbon content, total and mineral nitrogen amounts, carbon to nitrogen (C:N) ratio and redox potential depending on land usage and plant spieces. Soil samples were taken from the fields under...

  11. Nitrogen-Doped Carbon Quantum Dots as Fluorescent Probes for Sensitive and Selective Detection of Nitrite

    Directory of Open Access Journals (Sweden)

    Zhibiao Feng

    2017-11-01

    Full Text Available Nitrites are the upstream precursors of the carcinogenic nitrosamines, which are widely found in the natural environment and many food products. It is important to develop a simple and sensitive sensor for detecting nitrites. In this work, a fluorescence probe based on nitrogen-doped carbon quantum dots (N-CQDs was developed for the sensitive and selective determination of nitrites. At pH 2, the fluorescence of N-CQDs can be selectively quenched by nitrite due to the fact N-nitroso compounds can be formed in the reaction of amide groups with nitrous acid, which results in fluorescence static quenching. Under optimal conditions, fluorescence intensity quenching upon addition of nitrite gives a satisfactory linear relationship covering the linear range of 0.2–20 μM, and the limit of detection (LOD is 40 nM. Moreover, this method has been successfully applied to the determination of nitrites in tap water, which indicates its great potential for monitoring of nitrites in environmental samples.

  12. Impacts of Biochar on Physical Properties and Erosion Potential of a Mudstone Slopeland Soil

    Directory of Open Access Journals (Sweden)

    Zeng-Yei Hseu

    2014-01-01

    Full Text Available Food demand and soil sustainability have become urgent issues recently because of the global climate changes. This study aims to evaluate the application of a biochar produced by rice hull, on changes of physiochemical characteristics and erosion potential of a degraded slopeland soil. Rice hull biochar pyrolized at 400°C was incorporated into the soil at rates of 2.5%, 5%, and 10% (w/w and was incubated for 168 d in this study. The results indicated that biochar application reduced the Bd by 12% to 25% and the PR by 57% to 92% after incubation, compared with the control. Besides, porosity and aggregate size increased by 16% to 22% and by 0.59 to 0.94 mm, respectively. The results presented that available water contents significantly increased in the amended soils by 18% to 89% because of the obvious increase of micropores. The water conductivity of the biochar-amended soils was only found in 10% biochar treatment, which might result from significant increase of macropores and reduction of soil strength (Bd and PR. During a simulated rainfall event, soil loss contents significantly decreased by 35% to 90% in the biochar-amended soils. In conclusion, biochar application could availably raise soil quality and physical properties for tilth increasing in the degraded mudstone soil.

  13. Impacts of Biochar on Physical Properties and Erosion Potential of a Mudstone Slopeland Soil

    Science.gov (United States)

    Chien, Wei-Hsin; Liou, Ruei-Cheng

    2014-01-01

    Food demand and soil sustainability have become urgent issues recently because of the global climate changes. This study aims to evaluate the application of a biochar produced by rice hull, on changes of physiochemical characteristics and erosion potential of a degraded slopeland soil. Rice hull biochar pyrolized at 400°C was incorporated into the soil at rates of 2.5%, 5%, and 10% (w/w) and was incubated for 168 d in this study. The results indicated that biochar application reduced the Bd by 12% to 25% and the PR by 57% to 92% after incubation, compared with the control. Besides, porosity and aggregate size increased by 16% to 22% and by 0.59 to 0.94 mm, respectively. The results presented that available water contents significantly increased in the amended soils by 18% to 89% because of the obvious increase of micropores. The water conductivity of the biochar-amended soils was only found in 10% biochar treatment, which might result from significant increase of macropores and reduction of soil strength (Bd and PR). During a simulated rainfall event, soil loss contents significantly decreased by 35% to 90% in the biochar-amended soils. In conclusion, biochar application could availably raise soil quality and physical properties for tilth increasing in the degraded mudstone soil. PMID:25548787

  14. Relations of Pipe-to Soil Potential to the Local Geomagnetic and Telluric Activity

    Science.gov (United States)

    Larocca, P. A.; Trichtchenko, L.; Boteler, D. H.; Fernberg, P.

    2004-05-01

    Magnetic disturbances cause electric currents in long pipelines, which can contribute to corrosion of the pipeline. To protect the pipeline a cathodic protection system is used to maintain the pipeline at a constant negative potential with respect to surrounding soil that inhibits the corrosion reactions. However induced currents in the pipeline create variations in the pipe-to-soil potential taking. Knowing where and how often these potential variations occur is necessary for assessing the corrosion risk for a pipeline. Large pipe-to-soil potential variations have been observed on a pipeline from Armprior to Kemptville in eastern Ontario. We present observations and analysis of pipe-to-soil potential variations made in October 2003 to investigate why this area experienced such large fluctuations. Geomagnetic field recordings from the nearby Ottawa magnetic observatory were used with a 1-D multi-layered conductivity model of the Earth to calculate the electric field at the Earth surface. Comparison between the pipe-to-soil potential variations and the electric field variations gave correlation coefficients up to 90%. The pipe-to-soil potential recordings and calculated electric fields were used to determine a transfer function representing the pipe/earth response at each site. Comparison of these transfer functions from site to site shows where the peak response occurs. We examine the factors in the pipe structure and in the earth conductivity structure that could be the cause of these localized effects on the pipeline.

  15. Quantifying the underestimation of soil denitrification potential as determined by the acetylene inhibition method

    NARCIS (Netherlands)

    Qin, S.; Hu, C.; Oenema, O.

    2012-01-01

    The acetylene inhibition technique (AIT) is commonly used for the determination of soil denitrification potential (SDP). However, the results obtained with this technique have intrinsic uncertainties. This study aimed at quantifying these uncertainties. A silt loam topsoil from an experimental

  16. Agglomeration Determines Effects of Carbonaceous Nanomaterials on Soybean Nodulation, Dinitrogen Fixation Potential, and Growth in Soil

    Science.gov (United States)

    The potential effects of carbonaceous nanomaterials (CNMs) on agricultural plants are of concern. However, little research has been performed using plants cultivated to maturity in soils contaminated with various CNMs at different concentrations. Here, we grew soybean for 39 days...

  17. Extent of soil with low phosphorus retention potential in the United States Pacific Northwest

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This spatial data set was created by the U.S. Geological Survey (USGS) to represent the extent of soils with low phosphorus retention potential in the Pacific...

  18. Extent of soil with high phosphorus retention potential in the United States Pacific Northwest

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This spatial data set was created by the U.S. Geological Survey (USGS) to represent the extent of soils with high phosphorus retention potential in the Pacific...

  19. High-throughput fluorometric measurement of potential soil extracellular enzyme activities.

    Science.gov (United States)

    Bell, Colin W; Fricks, Barbara E; Rocca, Jennifer D; Steinweg, Jessica M; McMahon, Shawna K; Wallenstein, Matthew D

    2013-11-15

    Microbes in soils and other environments produce extracellular enzymes to depolymerize and hydrolyze organic macromolecules so that they can be assimilated for energy and nutrients. Measuring soil microbial enzyme activity is crucial in understanding soil ecosystem functional dynamics. The general concept of the fluorescence enzyme assay is that synthetic C-, N-, or P-rich substrates bound with a fluorescent dye are added to soil samples. When intact, the labeled substrates do not fluoresce. Enzyme activity is measured as the increase in fluorescence as the fluorescent dyes are cleaved from their substrates, which allows them to fluoresce. Enzyme measurements can be expressed in units of molarity or activity. To perform this assay, soil slurries are prepared by combining soil with a pH buffer. The pH buffer (typically a 50 mM sodium acetate or 50 mM Tris buffer), is chosen for the buffer's particular acid dissociation constant (pKa) to best match the soil sample pH. The soil slurries are inoculated with a nonlimiting amount of fluorescently labeled (i.e. C-, N-, or P-rich) substrate. Using soil slurries in the assay serves to minimize limitations on enzyme and substrate diffusion. Therefore, this assay controls for differences in substrate limitation, diffusion rates, and soil pH conditions; thus detecting potential enzyme activity rates as a function of the difference in enzyme concentrations (per sample). Fluorescence enzyme assays are typically more sensitive than spectrophotometric (i.e. colorimetric) assays, but can suffer from interference caused by impurities and the instability of many fluorescent compounds when exposed to light; so caution is required when handling fluorescent substrates. Likewise, this method only assesses potential enzyme activities under laboratory conditions when substrates are not limiting. Caution should be used when interpreting the data representing cross-site comparisons with differing temperatures or soil types, as in situ soil

  20. Links between Ammonia Oxidizer Community Structure, Abundance, and Nitrification Potential in Acidic Soils ▿ †

    Science.gov (United States)

    Yao, Huaiying; Gao, Yangmei; Nicol, Graeme W.; Campbell, Colin D.; Prosser, James I.; Zhang, Limei; Han, Wenyan; Singh, Brajesh K.

    2011-01-01

    Ammonia oxidation is the first and rate-limiting step of nitrification and is performed by both ammonia-oxidizing archaea (AOA) and bacteria (AOB). However, the environmental drivers controlling the abundance, composition, and activity of AOA and AOB communities are not well characterized, and the relative importance of these two groups in soil nitrification is still debated. Chinese tea orchard soils provide an excellent system for investigating the long-term effects of low pH and nitrogen fertilization strategies. AOA and AOB abundance and community composition were therefore investigated in tea soils and adjacent pine forest soils, using quantitative PCR (qPCR), terminal restriction fragment length polymorphism (T-RFLP) and sequence analysis of respective ammonia monooxygenase (amoA) genes. There was strong evidence that soil pH was an important factor controlling AOB but not AOA abundance, and the ratio of AOA to AOB amoA gene abundance increased with decreasing soil pH in the tea orchard soils. In contrast, T-RFLP analysis suggested that soil pH was a key explanatory variable for both AOA and AOB community structure, but a significant relationship between community abundance and nitrification potential was observed only for AOA. High potential nitrification rates indicated that nitrification was mainly driven by AOA in these acidic soils. Dominant AOA amoA sequences in the highly acidic tea soils were all placed within a specific clade, and one AOA genotype appears to be well adapted to growth in highly acidic soils. Specific AOA and AOB populations dominated in soils at particular pH values and N content, suggesting adaptation to specific niches. PMID:21571885

  1. The potential of gamma-ray spectrometry as supplementary information for mapping central European soils

    Science.gov (United States)

    Schuler, U.; Bock, M.; Baritz, R.; Willer, J.; Pickert, E.; Kardel, K.; Herrmann, L.

    2012-04-01

    Permanently updated soil maps are needed inter alia for the prediction of landslide hazards, flooding and drought effects, land degradation monitoring, and precision farming. Since comprehensive and intensive field mapping is not affordable, alternative mapping approaches are required. A promising tool, with quite unrecognised potential for modern soil science is gamma-ray spectrometry. As the radioelements potassium, thorium and uranium respond differently to soil forming processes, it should be possible to infer from their concentration on weathering status, and after calibration on soil properties and types. This paper aims to investigate the potential of airborne gamma spectrometry for mapping of central European soils and soil properties. The study was conducted for a test site in Southern Saxony, Germany, 140*85 km wide, representing diverse soil landscapes. Seven different petrographic training and validation areas were chosen each. To assess the potential of gamma-ray spectrometry as additional data layer, predictions were carried out (i) with and (ii) without radiometric data. The outputs were compared with independent soil information of the validation areas. Both prediction runs used the following predictors: elevation, slope, curvature, planform curvature, profile curvature, terrain ruggedness index, relative altitude, vertical distance above drainage network, wetness index, and convergence index. As additional predictor parent material derived from a reclassification of the official geological map (1:1M scale) was used. As radiometric properties potassium, thorium and uranium were used. The radiometric raster datasets were generated by universal kriging using relative altitude as covariate. Training and validation datasets were selected from a comprehensive dataset representing more than 14.000 point data. Point data include soil types and substrates, and for more than 800 sites soil profiles with analysed texture, pH, exchangeable cations, nutrients

  2. Radiation preservation of low nitrite bacon

    Science.gov (United States)

    Singh, Harwant

    Sodium nitrite, a key ingredient of the mix used to cure bacon and other meats, promotes and fixes bacon's characteristic pink color, inhibits lipid peroxidation and prevents growth of microorganisms, particularly Clostridium botulinum spores. Unfortunately, nitrite leads to the formation of carcinogenic nitrosamines in bacon. This has led to a search for alternatives to the use of nitrite. Irradiation with reduced level of nitrite is a promising alternative. Radurization of bacon containing 20 to 40 mg/kg of nitrite in evacuated packages, irradiated and stored at 4°C, gives a product with good organoleptic qualities and extended shelf life of ⩾ 90 days, as opposed to ˜ 30 days for the conventionally treated bacon. Radappertization of bacon containing 20 mg/kg of nitrite at a dose of about 30 kGy, irradiated at temperature of -20° or lower in evacuated packages, results in a product that is shelf stable at room temperature for months to years. It has organoleptic qualities comparable to commercial bacon in terms of color, flavor, odor and texture. Irradiation also reduces the nitrite and preformed nitrosamines present in bacon. Various aspects of preservation of bacon are reviewed in this report with emphasis on radiation processing.

  3. Copula-based Probabilistic Estimation of Soil Moisture and its Potential Application in Air Pollution Meteorology

    Science.gov (United States)

    Das, S. K.; Maity, R.

    2016-12-01

    Soil moisture at monthly to weekly scale for point locations can be simulated using climate inputs for different soil texture or hydrologic soil groups, based on the association between soil moisture and Combined Hydro-Meteorological (CHM) index. The use of Supervised PCA (SPCA) is found suitable for reducing the dimension of input matrix by deriving the CHM index and Archimedean copula as a tool to derive conditional joint distribution of soil moisture and climate inputs. While static copula is sufficient to capture the association at monthly scale, dynamic copula is appropriate for finer temporal scale, e.g. weekly. The simulated soil moisture both at monthly and weekly scale found to perform reasonably well compared to the existing soil moisture data sets. The simulated soil moisture at point location can be utilized to produce simulated soil moisture maps for a region based on results of cross-validation techniques, e.g. Leave One-station Out Cross-Validation (LOOCV). The gridded climate input data sets can be used for such mapping after treating the missing data points with interpolation techniques, like spring metaphor. Using such meteorologiac inputs, typical high resolution soil moisture maps are generated based on the proposed hydrometeorological approach. Such gridded soil moisture data/map are potentially useful in various fields including the assessment of air pollution meteorology as the mixing height directly depends on the rigional soil moisture content through intial spin-up of convective movement in the Atmospheric Boundary Layer (ABL). Keywords: Soil Moisture; Climate; Probabilistic Modelling; Copula; Hydrometeorology

  4. Potential microbial contamination during sampling of permafrost soil assessed by tracers

    DEFF Research Database (Denmark)

    Bang-Andreasen, Toke; Schostag, Morten; Priemé, Anders

    2017-01-01

    Drilling and handling of permanently frozen soil cores without microbial contamination is of concern because contamination e.g. from the active layer above may lead to incorrect interpretation of results in experiments investigating potential and actual microbial activity in these low microbial...... biomass environments. Here, we present an example of how microbial contamination from active layer soil affected analysis of the potentially active microbial community in permafrost soil. We also present the development and use of two tracers: (1) fluorescent plastic microspheres and (2) Pseudomonas...

  5. Microbial Degradation and Carbon Biosequestration Potential of Biochar in Contrasting Soils

    Science.gov (United States)

    Tas, N.; Castanha, C.; Reichl, K.; Fischer, M. L.; Brodie, E. L.; Torn, M. S.; Jansson, J. K.

    2012-12-01

    Biochar is a carbon-rich product that is produced by high-temperature and low-oxygen pyrolysis of biomass, whose addition to soil has been proposed as a promising method for carbon sequestration. Biochar carbon has been assumed to be stable in soil, but recent research shows that it is at least partly degradable by soil microbes. However, the influence of environmental conditions on microbial transformation of biochar is poorly understood. Our overall goal is to determine the factors that regulate microbial decomposition of biochar in soils. We performed laboratory incubation experiments to compare the potential for biochar decomposition in soils from contrasting ecosystems (tropical forest from Puerto Rico and Mediterranean grassland from California), varied temperatures (ambient and +6°C) and depths (A and B horizons). Soil incubations with pyrolyzed 13C-enriched wood were continuously monitored for heterotrophic respiration using an online Cavity Ringdown Spectrometer. Samples collected after 10 and 150 days of incubation were analyzed for the activity of extracellular enzymes while changes in microbial community composition were assessed via pyrotag sequencing of both 16S rRNA and 16S rRNA genes. 13C-CO2 measurements confirmed that a fraction of added biochar was degraded in both soils during the one-year incubation period. Biochar addition was associated with a decline in cellulose and hemicellulose degrading enzyme activity in grassland soils, although not in tropical soils. In both soils, native soil organic carbon decomposition was not significantly impacted by biochar addition. Principle coordinates analysis of microbial composition showed that both soils harbored different microbial communities and those communities at different depths were distinct. The main bacterial groups enriched by biochar addition were Actinobacteria in the grassland soil, and α-Proteobacteria, Actinobacteria and Acidobacteria in the tropical soil. Analysis of 16S r

  6. A universal meteorological method to identify potential risk of wind erosion on heavy-textured soils

    Directory of Open Access Journals (Sweden)

    Středová Hana

    2015-06-01

    Full Text Available The climate of Central Europe, mainly winter seasons with no snow cover at lower altitudes and a spring drought as well, might cause erosion events on heavy-textured soils. The aim of this paper is to define a universal method to identify the potential risk of wind erosion on heavy-textured soils. The categorization of potential wind erosion risk due to meteorological conditions is based on: (i an evaluation of the number of freeze-thaw episodes forming bare soil surfaces during the cold period of year; and (ii, an evaluation of the number of days with wet soil surfaces during the cold period of year. In the period 2001–2012 (from November to March, episodes with temperature changes from positive to negative and vice versa (thaw-freeze and freeze-thaw cycles and the effects of wet soil surfaces in connection with aggregate disintegration, are identified. The data are spatially interpolated by GIS tools for areas in the Czech Republic with heavy-textured soils. Blending critical categories is used to locate potential risks. The level of risk is divided into six classes. Those areas identified as potentially most vulnerable are the same localities where the highest number of erosive episodes on heavy-textured soils was documented.

  7. Plutonium in Soils from Northeast China and Its Potential Application for Evaluation of Soil Erosion

    DEFF Research Database (Denmark)

    Xu, Yihong; Qiao, Jixin; Hou, Xiaolin

    2013-01-01

    . While only half inventory of Pu was obtained in another soil core and no sub-surface maximum value occurred. Erosion of topsoil in the site should be the most possible reason for the significantly lower Pu inventory, which is also supported by the reported 137Cs profiles. These results demonstrated...... that Pu could be applied as an ideal substitute of 137Cs for soil erosion study in the future.......Surface and soil core samples from northeast China were analyzed for Pu isotopes. The measured 240Pu/239Pu atomic ratios and 239 1 240Pu/137Cs activity ratios revealed that the global fallout is the dominant source of Pu and 137Cs at these sites. Migration behavior of Pu varying with land type...

  8. Boletus edulis Nitrite Reductase Reduces Nitrite Content of Pickles and Mitigates Intoxication in Nitrite-intoxicated Mice

    National Research Council Canada - National Science Library

    Zhang, Weiwei; Tian, Guoting; Feng, Shanshan; Wong, Jack Ho; Zhao, Yongchang; Chen, Xiao; Wang, Hexiang; Ng, Tzi Bun

    2015-01-01

    Pickles are popular in China and exhibits health-promoting effects. However, nitrite produced during fermentation adversely affects health due to formation of methemoglobin and conversion to carcinogenic nitrosamine...

  9. Evidence for nitrite-dependent anaerobic methane oxidation as a previously overlooked microbial methane sink in wetlands

    Science.gov (United States)

    Hu, Bao-lan; Shen, Li-dong; Lian, Xu; Zhu, Qun; Liu, Shuai; Huang, Qian; He, Zhan-fei; Geng, Sha; Cheng, Dong-qing; Lou, Li-ping; Xu, Xiang-yang; Zheng, Ping; He, Yun-feng

    2014-01-01

    The process of nitrite-dependent anaerobic methane oxidation (n-damo) was recently discovered and shown to be mediated by “Candidatus Methylomirabilis oxyfera” (M. oxyfera). Here, evidence for n-damo in three different freshwater wetlands located in southeastern China was obtained using stable isotope measurements, quantitative PCR assays, and 16S rRNA and particulate methane monooxygenase gene clone library analyses. Stable isotope experiments confirmed the occurrence of n-damo in the examined wetlands, and the potential n-damo rates ranged from 0.31 to 5.43 nmol CO2 per gram of dry soil per day at different depths of soil cores. A combined analysis of 16S rRNA and particulate methane monooxygenase genes demonstrated that M. oxyfera-like bacteria were mainly present in the deep soil with a maximum abundance of 3.2 × 107 gene copies per gram of dry soil. It is estimated that ∼0.51 g of CH4 m−2 per year could be linked to the n-damo process in the examined wetlands based on the measured potential n-damo rates. This study presents previously unidentified confirmation that the n-damo process is a previously overlooked microbial methane sink in wetlands, and n-damo has the potential to be a globally important methane sink due to increasing nitrogen pollution. PMID:24616523

  10. In vitro influence of D/L-lactic acid, sodium chloride and sodium nitrite on the infectivity of feline calicivirus and of ECHO virus as potential surrogates for foodborne viruses.

    Science.gov (United States)

    Straube, J; Albert, T; Manteufel, J; Heinze, J; Fehlhaber, K; Truyen, U

    2011-11-15

    The importance of foodborne viruses is increasingly recognized. Thus, the effect of commonly used food preservation methods on the infectivity of viruses is questioned. In this context, we investigated the antiviral properties of D,L-lactic acid, sodium chloride and sodium nitrite by in vitro studies. Two model viruses, Feline Calicivirus (FCV) and Enteric Cytophatic Human Orphan (ECHO) virus, were chosen for this study simulating important foodborne viruses (human noroviruses (NoV) and human enteroviruses, resp.). The model viruses were exposed to different solutions of D,L-lactic acid (0.1-0.4% w/w, pH 6.0-3.2), of sodium chloride (2-20%, w/v) and of sodium nitrite (100, 150 and 200 ppm) at 4 and 20 °C for a maximum of 7 days. Different results were obtained for the two viruses. ECHO virus was highly stable against D,L-lactic acid and sodium chloride when tested under all conditions. On the contrary, FCV showed less stability but was not effectively inactivated when exposed to low acid and high salt conditions at refrigeration temperatures (4 °C). FCV titers decreased more markedly at 20 °C than 4 °C in all experiments. Sodium nitrite did not show any effect on the inactivation of both viruses. The results indicate that acidification, salting or curing maybe insufficient for effective inactivation of foodborne viruses such as NoV or human enteroviruses during food processing. Thus, application of higher temperature during fermentation and ripening processes maybe more effective toward the inactivation kinetics of less stable viruses. Nevertheless, more studies are needed to examine the antiviral properties of these preserving agents on virus survival and inactivation kinetics in the complex food matrix. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Effects of Nitrification Inhibitors on Mineral Nitrogen Dynamics in Agriculture Soils

    OpenAIRE

    Tindaon, Ferisman; Benckiser, Gero; Ottow, Johannes Carl Gottlieb

    2011-01-01

    Experiments were conducted under laboratory conditions to elucidate the effect of three nitrification inhibitors viz, 3.4dime-thylpyrazo-lephosphate (DMPP), 4-Chlormethylpyrazole (ClMP) and dicyandiamide (DCD) on mineral nitrogen dynamics of (NH4)2SO4 in soil incubated at 25oC in soils. The quantitative determination of ammonium, nitrite and nitrate were carried out spectrophotometrically, while potential denitrify-cation capacity (PDC) was measured gas chromatographically. DMPP, ClMP and DCD...

  12. The potential of coal combustion products as soft soil improvement materials

    Energy Technology Data Exchange (ETDEWEB)

    Awad, A.A.A. [WorsleyParsons Canada, Calgary, AB (Canada); Harahap, I.S. [Univ. Teknology Petronas, Tronoh (Malaysia)

    2010-07-01

    Buildings and embankment constructions are increasingly being built on soft soils, especially in south-east Asia countries. Such soils are subject to large volume changes, have low shear strength and relatively high moisture contents. Soil improvement techniques are therefore needed to address these issues. Stone columns and surface vibratory compaction are commonly used, but they are costly. The use of coal combustion products as a substitute for aggregates in concrete has been proposed as an innovative, efficient, less costly and more environmentally friendly soil improvement technique. This paper reported on a pilot study that was conducted at the University of Technology Petronas in Malaysia to investigate the potential of some coal combustion products, such as pulverized fly ash (PFA) and bottom ash (BA) as soil stabilization materials for soft soils. Specifically, the paper discussed the potential of coal combustion products, namely PFA and BA on the California Bearing Ratio (CBR). The paper discussed soft soils in Malaysia as well as the soil improvement technique. Testing and results were also presented. It was concluded that fly ash seems to be more effective in improving the CBR as compared to bottom ash. 15 refs., 2 tabs., 3 figs.

  13. Potential and limitations of multidecadal satellite soil moisture observations for selected climate model evaluation studies

    Directory of Open Access Journals (Sweden)

    A. Loew

    2013-09-01

    Full Text Available Soil moisture is an essential climate variable (ECV of major importance for land–atmosphere interactions and global hydrology. An appropriate representation of soil moisture dynamics in global climate models is therefore important. Recently, a first multidecadal, observation-based soil moisture dataset has become available that provides information on soil moisture dynamics from satellite observations (ECVSM, essential climate variable soil moisture. The present study investigates the potential and limitations of this new dataset for several applications in climate model evaluation. We compare soil moisture data from satellite observations, reanalysis and simulations from a state-of-the-art land surface model and analyze relationships between soil moisture and precipitation anomalies in the different dataset. Other potential applications like model parameter optimization or model initialization are not investigated in the present study. In a detailed regional study, we show that ECVSM is capable to capture well the interannual and intraannual soil moisture and precipitation dynamics in the Sahelian region. Current deficits of the new dataset are critically discussed and summarized at the end of the paper to provide guidance for an appropriate usage of the ECVSM dataset for climate studies.

  14. Potential use of DNA adducts to detect mutagenic compounds in soil

    Energy Technology Data Exchange (ETDEWEB)

    Hua Guoxiong [School of Biology, Institute for Research on the Environment and Sustainability, Devonshire Building, Newcastle University, NE1 7RU (United Kingdom)], E-mail: gh15@st-andrews.ac.uk; Lyons, Brett [CEFAS Weymouth Laboratory, Barrack Road, The Nothe, Weymouth, Dorset, DT4 8UB (United Kingdom); Killham, Ken [School of Biology, Cruickshank Building, University of Aberdeen, AB24 3UU (United Kingdom); Singleton, Ian [School of Biology, Institute for Research on the Environment and Sustainability, Devonshire Building, Newcastle University, NE1 7RU (United Kingdom)], E-mail: ian.singleton@ncl.ac.uk

    2009-03-15

    In this study, three different soils with contrasting features, spiked with 300 mg benzo[a]pyrene (BaP)/kg dry soil, were incubated at 20 deg. C and 60% water holding capacity for 540 days. At different time points, BaP and DNA were extracted and quantified, and DNA adducts were quantified by {sup 32}P-postlabelling. After 540 days incubation, 69.3, 81.6 and 83.2% of initial BaP added remained in Cruden Bay, Boyndie and Insch soils, respectively. Meanwhile, a significantly different amount of DNA-BaP adducts were found in the three soils exposed to BaP over time. The work demonstrates the concept that DNA adducts can be detected on DNA extracted from soil. Results suggest the technique is not able to directly reflect bioavailability of BaP transformation products. However, this new method provides a potential way to detect mutagenic compounds in contaminated soil and to assess the outcomes of soil remediation. - A novel DNA adduct assay may provide a potential technique to detect mutagenic compounds in contaminated soil.

  15. Is mean residence time a useful tool to evaluate carbon sequestration in soils? Limits and potential

    Science.gov (United States)

    Abiven, Samuel; Gonzalez-Dominguez, Beatriz; Studer, Mirjam

    2017-04-01

    Soils are increasingly recognized as a serious candidate to store large amounts of carbon. International efforts, like the 4 per mil initiative, are promoting soil-related solutions to retain carbon at long timescales. The options are quite diverse, from biochar or root promoting agricultural techniques to existing large vulnerable soil organic matter stock conservation policies. However, the evaluation of these techniques is not easy. The changes of soil organic carbon stocks are difficult to detect on the short term: carbon stock estimations suffer from technical hurdles, like bulk density estimation or access to the subsoil carbon; the soil is by nature heterogeneous, and generalization of results for a given situation are difficult to upscale. The evaluation of soil organic matter mean residence time (MRT) may be used to describe the potential of these solutions. In soils, MRT is calculated by isotopic techniques (i.e. stable or radioactive isotopes) or by mass balances (i.e. measured or calculated based in CO2 emissions). Depending on the method applied, results may vary greatly and may also describe different facets of the soil organic matter continuum. For example, MRT calculated with 14C data depends on molecules with long residence time while MRT based on mass balance calculations are triggered by fresh inputs that may decompose relatively fast in soils. Based on a comprehensive Swiss forest soils dataset allowing us to calculate soil organic matter MRT by different approaches and a series of recent literature considerations about the MRT, we will discuss the potential of MRT to be applied for carbon storage evaluation.

  16. New composite nitrite-free and low-nitrite meat-curing systems using natural colorants.

    Science.gov (United States)

    Eskandari, Mohammad H; Hosseinpour, Sara; Mesbahi, Gholamreza; Shekarforoush, Shahram

    2013-09-01

    Nitrite-free and low-nitrite meat-curing systems were developed to eliminate or reduce nitrite in frankfurter-type sausages. Different composite meat-curing mixtures were formulated using cochineal and paprika as natural colorants, sodium hypophosphite (SHP) as antimicrobial agent, butylated hydroxyanisole (BHA) as antioxidant and sodium nitrite. The treatment, which contained 0.015% cochineal, most closely resembled the 120 ppm NaNO2 in its ability to create cured-meat color. BHA was found to be a strong antioxidant at the 30 ppm level in cooked sausages during refrigerated storage for 5 weeks. All treatments containing 40 ppm sodium nitrite were successful in replicating sensory attributes of frankfurter samples. Our findings support the use of SHP as possible antibotulinal agent in nitrite-free meat-curing systems.

  17. Measurements of the streaming potential of clay soils from tropical and subtropical regions using self-made apparatus.

    Science.gov (United States)

    Li, Zhong-Yi; Li, Jiu-Yu; Liu, Yuan; Xu, Ren-Kou

    2014-09-01

    The streaming potential has been wildly used in charged parallel plates, capillaries, and porous media. However, there have been few studies involving the ζ potential of clay soils based on streaming potential measurements. A laboratory apparatus was developed in this study to measure the streaming potential (ΔE) of bulk clay soils' coupling coefficient (C) and cell resistance (R) of saturated granular soil samples. Excellent linearity of ΔE versus liquid pressure (ΔP) ensured the validity of measurements. The obtained parameters of C and R can be used to calculate the ζ potential of bulk soils. The results indicated that the ζ potentials measured by streaming potential method were significantly correlated with the ζ potentials of soil colloids determined by electrophoresis (r (2) = 0.960**). Therefore, the streaming potential method can be used to study the ζ potentials of bulk clay soils. The absolute values of the ζ potentials of four soils followed the order: Ultisol from Jiangxi > Ultisol from Anhui > Oxisol from Guangdong > Oxisol from Hainan, and this was consistent with the cation exchange capacities of these soils. The type and concentration of electrolytes affected soil ζ potentials. The ζ potential became less negative with increased electrolyte concentration. The ζ potentials were more negative in monovalent than in divalent cationic electrolyte solutions because more divalent cations were distributed in the shear plane of the diffuse layer as counter-cations on the soil surfaces than monovalent cations at the same electrolyte concentration.

  18. Community Analysis of Ammonia and Nitrite Oxidizers during Start-Up of Nitritation Reactors

    OpenAIRE

    Egli, Konrad; Langer, Christian; Siegrist, Hans-Ruedi; Zehnder, Alexander J. B.; Wagner, Michael; van der Meer, Jan Roelof

    2003-01-01

    Partial nitrification of ammonium to nitrite under oxic conditions (nitritation) is a critical process for the effective use of alternative nitrogen removal technologies from wastewater. Here we investigated the conditions which promote establishment of a suitable microbial community for performing nitritation when starting from regular sewage sludge. Reactors were operated in duplicate under different conditions (pH, temperature, and dilution rate) and were fed with 50 mM ammonium either as ...

  19. Post Chlorine gas exposure administration of nitrite prevents lung injury: effect of administration modality

    Science.gov (United States)

    Samal, Andrey A.; Honavar, Jaideep; Brandon, Angela; Bradley, Kelley M.; Doran, Stephen; Liu, Yanping; Dunaway, Chad; Steele, Chad; Postlethwait, Edward M.; Squadrito, Giuseppe L.; Fanucchi, Michelle V.; Matalon, Sadis; Patel, Rakesh P.

    2012-01-01

    lung permeability and inflammation. These data highlight the potential for nitrite as a post-exposure therapeutic for Cl2 gas induced lung injury and also suggest that administration modality is a key consideration in nitrite therapeutics. PMID:22917977

  20. Administration of nitrite after chlorine gas exposure prevents lung injury: effect of administration modality.

    Science.gov (United States)

    Samal, Andrey A; Honavar, Jaideep; Brandon, Angela; Bradley, Kelley M; Doran, Stephen; Liu, Yanping; Dunaway, Chad; Steele, Chad; Postlethwait, Edward M; Squadrito, Giuseppe L; Fanucchi, Michelle V; Matalon, Sadis; Patel, Rakesh P

    2012-10-01

    nitrite dose dependence for inhibition of Cl(2)-dependent lung permeability and inflammation. These data highlight the potential for nitrite as a postexposure therapeutic for Cl(2) gas-induced lung injury and also suggest that administration modality is a key consideration in nitrite therapeutics. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Nitrate, Nitrite, and nitroso compounds in foods

    Energy Technology Data Exchange (ETDEWEB)

    Hotchkiss, J.H.; Cassens, R.G.

    1987-04-01

    The concern that human foods might contain nitroso compounds stems from the discovery in the early 1960s that domestic animals fed fish meal preserved with high levels of sodium nitrite were dying of liver failure. It has been known for many years that nitrite can combine with amines to form N-nitrosamines. N-nitrosodimethylamine was determined to be the cause of the liver failure. The nitrosamine resulted from the reaction between dimethylamine contained in the fish and the added nitrite. Because nitrite is an important and widely used human food additive, particularly in the curing of meats, poultry, and fish, research was undertaken by several groups around the world to investigate the occurrence of these compounds in human foods.

  2. Effect of water potential and antecedent soil moisture on soil erodibility for coarse and fine-grained agricultural soils

    Science.gov (United States)

    Soil erodibility has confounded researchers for decades. Difficulties arise with initiation of motion, pore-water status, physical, and perhaps biological, material properties and type of applied energy (i.e. rainfall, runoff, freeze/thaw, wind). Though specific tests have been developed to determin...

  3. Nitrite Biosensing via Selective Enzymes—A Long but Promising Route

    Directory of Open Access Journals (Sweden)

    M. Gabriela Almeida

    2010-12-01

    Full Text Available The last decades have witnessed a steady increase of the social and political awareness for the need of monitoring and controlling environmental and industrial processes. In the case of nitrite ion, due to its potential toxicity for human health, the European Union has recently implemented a number of rules to restrict its level in drinking waters and food products. Although several analytical protocols have been proposed for nitrite quantification, none of them enable a reliable and quick analysis of complex samples. An alternative approach relies on the construction of biosensing devices using stable enzymes, with both high activity and specificity for nitrite. In this paper we review the current state-of-the-art in the field of electrochemical and optical biosensors using nitrite reducing enzymes as biorecognition elements and discuss the opportunities and challenges in this emerging market.

  4. Changes of sodium nitrate, nitrite, and N-nitrosodiethylamine during in vitro human digestion.

    Science.gov (United States)

    Kim, Hyeong Sang; Hur, Sun Jin

    2017-06-15

    This study aimed to determine the changes in sodium nitrate, sodium nitrite, and N-nitrosodiethylamine (NDEA) during in vitro human digestion, and the effect of enterobacteria on the changes in these compounds. The concentrations of nitrate, nitrite, and NDEA were significantly reduced from 150, 150, and 1ppm to 42.8, 63.2, and 0.85ppm, respectively, during in vitro human digestion (p<0.05). The enterobacteria Escherichia coli and Lactobacillus casei reduced the amount of these compounds present during in vitro human digestion. This study is the first to report that E. coli can dramatically reduce the amount of nitrite during in vitro human digestion and this may be due to the effect of nitrite reductase present in E. coli. We therefore conclude that the amounts of potentially harmful substances and their toxicity can be decreased during human digestion. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Potential use of fly ash to soil treatment in the Morava region

    Science.gov (United States)

    Bulíková, Lucia; Kresta, František; Rochovanský, Martin

    2017-09-01

    Soil treatment by binders is a standard technology and leads to optimal utilization of excavated soils in road constructions. Soil treatment is controlled in the Czech Republic by EN 14227-15 and Technical Requirement TP 94. Soil treatment using fly ash has not been performed in the Czech Republic, although there is a sufficient normative base. Fly ash produced by burning of hard coal in the Moravian region was tested as a potential binder. Fly ash samples were mixed with loess loams (CI). Tested siliceous fly ash of class F (ASTM C618) did not showed hydraulic properties but it showed positive effect on reducing maximum dry density of mixtures, increasing the IBI value (Immediate bearing index) and decreasing tendency to volume changes when the amount of fly ash was increased. The results of laboratory tests demonstrate the possibility of using fly ashes as a binder for soil treatment.

  6. Modelling Soil Water Retention for Weed Seed Germination Sensitivity to Water Potential

    Directory of Open Access Journals (Sweden)

    W. John Bullied

    2012-01-01

    Full Text Available Soil water retention is important for the study of water availability to germinating weed seeds. Six soil water retention models (Campbell, Brooks-Corey, four- and five-parameter van Genuchten, Tani, and Russo with residual soil water parameter derivations were evaluated to describe water retention for weed seed germination at minimum threshold soil water potential for three hillslope positions. The Campbell, Brooks-Corey, and four-parameter van Genuchten model with modified or estimated forms of the residual parameter had superior but similar data fit. The Campbell model underestimated water retention at a potential less than −0.5 MPa for the upper hillslope that could result in underestimating seed germination. The Tani and Russo models overestimated water retention at a potential less than −0.1 MPa for all hillslope positions. Model selection and residual parameter specification are important for weed seed germination by representing water retention at the level of minimum threshold water potential for germination. Weed seed germination models driven by the hydrothermal soil environment rely on the best-fitting soil water retention model to produce dynamic predictions of seed germination.

  7. Potential for monitoring soil erosion features and soil erosion modeling components from remotely sensed data

    Science.gov (United States)

    Langran, K. J.

    1983-01-01

    Accurate estimates of soil erosion and its effects on soil productivity are essential in agricultural decision making and planning from the field scale to the national level. Erosion models have been primarily developed for designing erosion control systems, predicting sediment yield for reservoir design, predicting sediment transport, and simulating water quality. New models proposed are more comprehensive in that the necessary components (hydrology, erosion-sedimentation, nutrient cycling, tillage, etc.) are linked in a model appropriate for studying the erosion-productivity problem. Recent developments in remote sensing systems, such as Landsat Thematic Mapper, Shuttle Imaging Radar (SIR-B), etc., can contribute significantly to the future development and operational use of these models.

  8. Simulating sunflower canopy temperatures to infer root-zone soil water potential

    Science.gov (United States)

    Choudhury, B. J.; Idso, S. B.

    1983-01-01

    A soil-plant-atmosphere model for sunflower (Helianthus annuus L.), together with clear sky weather data for several days, is used to study the relationship between canopy temperature and root-zone soil water potential. Considering the empirical dependence of stomatal resistance on insolation, air temperature and leaf water potential, a continuity equation for water flux in the soil-plant-atmosphere system is solved for the leaf water potential. The transpirational flux is calculated using Monteith's combination equation, while the canopy temperature is calculated from the energy balance equation. The simulation shows that, at high soil water potentials, canopy temperature is determined primarily by air and dew point temperatures. These results agree with an empirically derived linear regression equation relating canopy-air temperature differential to air vapor pressure deficit. The model predictions of leaf water potential are also in agreement with observations, indicating that measurements of canopy temperature together with a knowledge of air and dew point temperatures can provide a reliable estimate of the root-zone soil water potential.

  9. Potential microbial risk factors related to soil amendments and irrigation water of potato crops.

    Science.gov (United States)

    Selma, M V; Allende, A; López-Gálvez, F; Elizaquível, P; Aznar, R; Gil, M I

    2007-12-01

    This study assesses the potential microbial risk factors related to the use of soil amendments and irrigation water on potato crops, cultivated in one traditional and two intensive farms during two harvest seasons. The natural microbiota and potentially pathogenic micro-organisms were evaluated in the soil amendment, irrigation water, soil and produce. Uncomposted amendments and residual and creek water samples showed the highest microbial counts. The microbial load of potatoes harvested in spring was similar among the tested farms despite the diverse microbial levels of Listeria spp. and faecal coliforms in the potential risk sources. However, differences in total coliform load of potato were found between farms cultivated in the autumn. Immunochromatographic rapid tests and the BAM's reference method (Bacteriological Analytical Manual; AOAC International) were used to detect Escherichia coli O157:H7 from the potential risk sources and produce. Confirmation of the positive results by polymerase chain reaction procedures showed that the immunochromatographic assay was not reliable as it led to false-positive results. The potentially pathogenic micro-organisms of soil amendment, irrigation water and soil samples changed with the harvest seasons and the use of different agricultural practices. However, the microbial load of the produce was not always influenced by these risk sources. Improvements in environmental sample preparation are needed to avoid interferences in the use of immunochromatographic rapid tests. The potential microbial risk sources of fresh produce should be regularly controlled using reliable detection methods to guarantee their microbial safety.

  10. Sustainable Soil Washing: Shredded Card Filtration of Potentially Toxic Elements after Leaching from Soil Using Organic Acid Solutions.

    Directory of Open Access Journals (Sweden)

    Christopher Ash

    Full Text Available Shredded card (SC was assessed for use as a sorbent of potentially toxic elements (PTE carried from contaminated soil in various leachates (oxalic acid, formic acid, CaCl2, water. We further assessed SC for retention of PTE, using acidified water (pH 3.4. Vertical columns and a peristaltic pump were used to leach PTE from soils (O and A/B horizons before passing through SC. Sorption onto SC was studied by comparing leachates, and by monitoring total PTE contents on SC before and after leaching. SC buffers against acidic soil conditions that promote metals solubility; considerable increases in solution pH (+4.49 were observed. Greatest differences in solution PTE content after leaching with/without SC occurred for Pb. In oxalic acid, As, Cd, Pb showed a high level of sorption (25, 15, and 58x more of the respective PTE in leachates without SC. In formic acid, Pb sorption was highly efficient (219x more Pb in leachate without SC. In water, only Pb showed high sorption (191x more Pb in leachate without SC. In desorption experiments, release of PTE from SC varied according to the source of PTE (organic/mineral soil, and type of solvent used. Arsenic was the PTE most readily leached in desorption experiments. Low As sorption from water was followed by fast release (70% As released from SC. A high rate of Cd sorption from organic acid solutions was followed by strong retention (~12% Cd desorption. SC also retained Pb after sorption from water, with subsequent losses of ≤8.5% of total bound Pb. The proposed use of this material is for the filtration of PTE from extract solution following soil washing. Low-molecular-mass organic acids offer a less destructive, biodegradable alternative to strong inorganic acids for soil washing.

  11. Analyses of soil microbial community compositions and functional genes reveal potential consequences of natural forest succession.

    Science.gov (United States)

    Cong, Jing; Yang, Yunfeng; Liu, Xueduan; Lu, Hui; Liu, Xiao; Zhou, Jizhong; Li, Diqiang; Yin, Huaqun; Ding, Junjun; Zhang, Yuguang

    2015-05-06

    The succession of microbial community structure and function is a central ecological topic, as microbes drive the Earth's biogeochemical cycles. To elucidate the response and mechanistic underpinnings of soil microbial community structure and metabolic potential relevant to natural forest succession, we compared soil microbial communities from three adjacent natural forests: a coniferous forest (CF), a mixed broadleaf forest (MBF) and a deciduous broadleaf forest (DBF) on Shennongjia Mountain in central China. In contrary to plant communities, the microbial taxonomic diversity of the DBF was significantly (P cycling genes showed the network for the DBF samples was relatively large and tight, revealing strong couplings between microbes. Soil temperature, reflective of climate regimes, was important in shaping microbial communities at both taxonomic and functional gene levels. As a first glimpse of both the taxonomic and functional compositions of soil microbial communities, our results suggest that microbial community structure and function potentials will be altered by future environmental changes, which have implications for forest succession.

  12. Net sulfur mineralization potential in Swedish arable soils in relation to long-term treatment history and soil properties

    DEFF Research Database (Denmark)

    Boye, Kristin; Nilsson, S Ingvar; Eriksen, Jørgen

    2009-01-01

    The long-term treatment effect (since 1957-1966) of farmyard manure (FYM) application compared with crop residue incorporation was investigated in five soils (sandy loam to silty clay) with regards to the net sulfur (S) mineralization potential. An open incubation technique was used to determine ...... to SAccMin. Conclusively, different treatment histories influenced the quality (e.g., chemical composition) and cycling rate of the organic S pool, rather than its size...

  13. Simulating soybean canopy temperature as affected by weather variables and soil water potential

    Science.gov (United States)

    Choudhury, B. J.

    1982-01-01

    Hourly weather data for several clear sky days during summer at Phoenix and Baltimore which covered a wide range of variables were used with a plant atmosphere model to simulate soybean (Glycine max L.) leaf water potential, stomatal resistance and canopy temperature at various soil water potentials. The air and dew point temperatures were found to be the significant weather variables affecting the canopy temperatures. Under identical weather conditions, the model gives a lower canopy temperature for a soybean crop with a higher rooting density. A knowledge of crop rooting density, in addition to air and dew point temperatures is needed in interpreting infrared radiometric observations for soil water status. The observed dependence of stomatal resistance on the vapor pressure deficit and soil water potential is fairly well represented. Analysis of the simulated leaf water potentials indicates overestimation, possibly due to differences in the cultivars.

  14. Nitrate decreases xanthine oxidoreductase-mediated nitrite reductase activity and attenuates vascular and blood pressure responses to nitrite

    Directory of Open Access Journals (Sweden)

    Célio Damacena-Angelis

    2017-08-01

    Full Text Available Nitrite and nitrate restore deficient endogenous nitric oxide (NO production as they are converted back to NO, and therefore complement the classic enzymatic NO synthesis. Circulating nitrate and nitrite must cross membrane barriers to produce their effects and increased nitrate concentrations may attenuate the nitrite influx into cells, decreasing NO generation from nitrite. Moreover, xanthine oxidoreductase (XOR mediates NO formation from nitrite and nitrate. However, no study has examined whether nitrate attenuates XOR-mediated NO generation from nitrite. We hypothesized that nitrate attenuates the vascular and blood pressure responses to nitrite either by interfering with nitrite influx into vascular tissue, or by competing with nitrite for XOR, thus inhibiting XOR-mediated NO generation. We used two independent vascular function assays in rats (aortic ring preparations and isolated mesenteric arterial bed perfusion to examine the effects of sodium nitrate on the concentration-dependent responses to sodium nitrite. Both assays showed that nitrate attenuated the vascular responses to nitrite. Conversely, the aortic responses to the NO donor DETANONOate were not affected by sodium nitrate. Further confirming these results, we found that nitrate attenuated the acute blood pressure lowering effects of increasing doses of nitrite infused intravenously in freely moving rats. The possibility that nitrate could compete with nitrite and decrease nitrite influx into cells was tested by measuring the accumulation of nitrogen-15-labeled nitrite (15N-nitrite by aortic rings using ultra-performance liquid chromatography tandem mass-spectrometry (UPLC-MS/MS. Nitrate exerted no effect on aortic accumulation of 15N-nitrite. Next, we used chemiluminescence-based NO detection to examine whether nitrate attenuates XOR-mediated nitrite reductase activity. Nitrate significantly shifted the Michaelis Menten saturation curve to the right, with a 3-fold increase in

  15. The dependence of water potential in shoots of Picea abies on air and soil water status

    Directory of Open Access Journals (Sweden)

    A. Sellin

    Full Text Available Where there is sufficient water storage in the soil the water potential (Ψx in shoots of Norway spruce [Picea abies (L. Karst.] is strongly governed by the vapour pressure deficit of the atmosphere, while the mean minimum values of Ψx usually do not drop below –1.5 MPa under meteorological conditions in Estonia. If the base water potential (Ψb is above –0.62 MPa, the principal factor causing water deficiency in shoots of P. abies may be either limited soil water reserves or atmospheric evaporative demand depending on the current level of the vapour pressure deficit. As the soil dries the stomatal control becomes more efficient in preventing water losses from the foliage, and the leaf water status, in turn, less sensitive to atmospheric demand. Under drought conditions, if Ψb falls below –0.62 MPa, the trees' water stress is mainly caused by low soil water availability. Further declines in the shoot water potential (below –1.5 MPa can be attributed primarily to further decreases in the soil water, i.e. to the static water stress.Key words. Hydrology (evapotranspiration · plant ecology · soil moisture.

  16. Comparison of phytoremediation potential of three grass species in soil contaminated with cadmium

    Directory of Open Access Journals (Sweden)

    Gołda Sylwia

    2016-03-01

    Full Text Available The aim of the study was to compare the toleration of Poa pratensis, Lolium perenne and Festuca rubra to cadmium contamination as well as the phytoremediation potential of these three species of grass. The pot experiment was conducted in four replications in pots containing 2.0 kg of soil. The soil was contaminated with three doses of Cd – 30, 60 and 120 mg·kg−1. After two months, the aerial parts of plants were harvested. The roots were dug up, brushed off from the remaining soil and washed with water. The biomass was defined and the cadmium concentration was determined in aerial parts and roots. The phytoremediation potential of grasses was evaluated using biomass of grasses, bioaccumulation factor (BF and translocation factor (TF. All three tested species of grasses had TF 1. It indicates their suitability for phytostabilisation and makes them unsuitable for phytoextraction of Cd from the soil. Comparing the usefulness of the tested grasses for phytoremediation has shown that the phytostabilisation potential of P. pratensis was lower than that of L. perenne and F. rubra. P. pratensis was distinguished by higher TF, smaller root biomass and lower tolerance for Cd excess in the soil in comparison with the two other test grasses. At the same time, L. perenne was characterised by the smallest decrease in biomass and the largest Cd accumulation in roots at the lowest dose of Cd. It indicates good usefulness for phytostabilisation of soils characterised by a relatively small pollution by cadmium.

  17. Identification of 300 Area Contaminants of Potential Concern for Soil

    Energy Technology Data Exchange (ETDEWEB)

    R.W. Ovink

    2010-04-05

    This report documents the process used to identify source area contaminants of potential concern (COPCs) in support of the 300 Area remedial investigation/feasibility study (RI/FS) work plan. This report also establishes the exclusion criteria applicable for 300 Area use and the analytical methods needed to analyze the COPCs.

  18. UV-irradiation enhances rice allelopathic potential in rhizosphere soil

    DEFF Research Database (Denmark)

    Mahmood, Khalid; Khan, Muhammad Bismillah; Song, Yuan Yuan

    2013-01-01

    Ultraviolet-B radiation is rising continuously due to stratospheric ozone depletion over temperate latitudes. This study investigated effects of UV exposure on rice allelopathic potentials. For this purpose, two rice (Oryza sativa L.) cultivars BR-41 (high allelopathic = able to inhibit neighbori...

  19. Soil weed seedbank dynamic and allelopathic potential of Tithonia ...

    African Journals Online (AJOL)

    The phenomenon of allelopathy is receiving increased attention as a possible alternative weed control method that is environment-friendly when compared with the use of herbicides with a wide range of toxic side effects which pose potential hazards to the environment. This study was designed to estimate the distribution of ...

  20. Potentiality of Melastoma malabathricum as Phytoremediators of soil contaminated with sewage sludge

    Directory of Open Access Journals (Sweden)

    Nur-Nazirah Patek-Mohd

    Full Text Available ABSTRACT: Heavy metal pollution of the soil environment has become a major source of concern and continues to pose serious health problems to both humans and ecological systems worldwide. Phytoremediation is a biological treatment whereby plants are used to remove pollutant from the environment. An experiment was conducted to evaluate the potential of Melastoma malabathricum as a phytoremediator to absorb heavy metals from soil contaminated with sewage sludge. Melastoma malabathricum seedlings were planted on six different growth media: T0 - Control (100 % soil, T1 (80 % soil + 20 % sewage sludge, T2 (60 % soil + 40 % sewage sludge, T3 (40 % soil + 60 % sewage sludge, T4 (20 % soil + 80 % sewage sludge and T5 (100 % sludge. There were differences found in both growth parameters and plant biomass. The highest growth performance such as plant height and number of leaves was found in T3. Iron was highly accumulated in the roots, Cu in the stems in T3, while Pb was accumulated in leaves in T5. The results showed the lowest Translocation Factor (TF and highest Bioconcentration Factor (BCF values in relation to the following elements: Cu, Fe, Mn, Pb and Zn. Melastoma malabathricum roots are able to uptake and translocate the elements into the plant's shoots. Therefore, it can be considered a good accumulator plant due to its capability of concentrating contaminants in aerial tissue. Melastoma malabathricum were thus found to be suitable for absorbing heavy metals in contaminated soils, and this species can also be considered an effective phtyoremediator of contaminated soil and mitigator of soil pollution.

  1. Genotoxic and mutagenic potential of agricultural soil irrigated with tannery effluents at Jajmau (Kanpur), India.

    Science.gov (United States)

    Alam, Mohammad Zubair; Ahmad, Shamim; Malik, Abdul

    2009-10-01

    It is a common practice in India to irrigate agricultural fields with wastewater originating from industries and domestic sources. At Jajmau (Kanpur), India, tannery effluent is used for irrigation purposes. This practice has been polluting the soil directly and groundwater and food crops indirectly. This study is aimed at evaluating the mutagenic impact of soil irrigated with tannery effluent. Soil extracts were prepared using four organic solvents (dichloromethane, methanol, acetonitrile, and acetone) and tested with Ames Salmonella/microsome test and DNA repair-defective E. coli k-12 mutants. Gas Chromatography-mass spectrometric analysis of soil samples revealed the presence of a large number of organic compounds including bis(2-ethylhexyl)phthalate, benzene, 1,3-hexadien-5-yne, 2,4-bis(1,1-dimethyl)phenol, Docosane, 10-methylnonadecane, and many higher alkanes. The soil extracts exhibited significant mutagenicity with Ames tester strains. TA98 was found to be the most sensitive strains to all the soil extracts, producing maximum response in terms of mutagenic index of 14.2 (-S9) and 13.6 (+S9) in the presence of dichloromethane extract. Dichloromethane-extracted soil exhibited a maximum mutagenic potential of 17.3 (-S9) and 20.0 (+S9) revertants/mg soil equivalent in TA100. Methanol, acetonitrile, and acetone extracts were also found to be mutagenic. A significant decline in the survival of DNA repair-defective E. coli K-12 mutants was observed compared to their isogenic wild-type counterparts when treated with different soil extracts. PolA mutant was found to be the most sensitive strain toward all four soil extracts.

  2. A new system for the spectrophotometric determination of trace amounts of nitrite in environmental samples

    Directory of Open Access Journals (Sweden)

    Cherian Tom

    2006-01-01

    Full Text Available A selective and rapid spectrophotometric method for the determination of nitrite is presented. It is based on the reaction of nitrite with p-nitroaniline in acid medium to form diazonium ion, which is coupled with ethoxyethylenemaleic ester or ethylcyanoacetate in basic medium to form azo dyes, showing absorption maxima at 439 and 465 nm respectively. The method obeys Beer's law in the concentration range of 0.5-16 µg mL-1 of nitrite with ethoxyethylenemaleic ester and 0.2-18 µg mL-1 of nitrite with ethylcyanoacetate. The molar absorptivity and Sandell's sensitivity of p-nitroaniline-ethoxyethylenemaleic ester and p-nitroaniline-ethylcyanoacetate azo dyes are 5.04 X 10(4 L mol-1cm-1, 0.98 X 10-2 µg cm-2 and 1.21 X 10(4 L mol-1 cm-1, 0.98 X 10-2 µg cm-2 respectively. The optimum reaction conditions and other analytical parameters were evaluated. The method was successfully applied to the determination of nitrite in various water samples and soil samples.

  3. Plant trait diversity buffers variability in denitrification potential over changes in season and soil conditions.

    Directory of Open Access Journals (Sweden)

    Bonnie M McGill

    Full Text Available BACKGROUND: Denitrification is an important ecosystem service that removes nitrogen (N from N-polluted watersheds, buffering soil, stream, and river water quality from excess N by returning N to the atmosphere before it reaches lakes or oceans and leads to eutrophication. The denitrification enzyme activity (DEA assay is widely used for measuring denitrification potential. Because DEA is a function of enzyme levels in soils, most ecologists studying denitrification have assumed that DEA is less sensitive to ambient levels of nitrate (NO(3(- and soil carbon and thus, less variable over time than field measurements. In addition, plant diversity has been shown to have strong effects on microbial communities and belowground processes and could potentially alter the functional capacity of denitrifiers. Here, we examined three questions: (1 Does DEA vary through the growing season? (2 If so, can we predict DEA variability with environmental variables? (3 Does plant functional diversity affect DEA variability? METHODOLOGY/PRINCIPAL FINDINGS: The study site is a restored wetland in North Carolina, US with native wetland herbs planted in monocultures or mixes of four or eight species. We found that denitrification potentials for soils collected in July 2006 were significantly greater than for soils collected in May and late August 2006 (p<0.0001. Similarly, microbial biomass standardized DEA rates were significantly greater in July than May and August (p<0.0001. Of the soil variables measured--soil moisture, organic matter, total inorganic nitrogen, and microbial biomass--none consistently explained the pattern observed in DEA through time. There was no significant relationship between DEA and plant species richness or functional diversity. However, the seasonal variance in microbial biomass standardized DEA rates was significantly inversely related to plant species functional diversity (p<0.01. CONCLUSIONS/SIGNIFICANCE: These findings suggest that

  4. Practical improvements in soil redox potential (Eh) measurement for characterisation of soil properties. Application for comparison of conventional and conservation agriculture cropping systems

    Energy Technology Data Exchange (ETDEWEB)

    Husson, Olivier, E-mail: Olivier.husson@cirad.fr [CIRAD/PERSYST/UPR 115 AIDA and AfricaRice Centre, 01 BP 2031 Cotonou (Benin); Husson, Benoit, E-mail: bhusson@ideeaquaculture.com [IDEEAQUACULTURE, Parc Euromédecine 2, 39 Rue Jean Giroux, 34080 Montpellier (France); Brunet, Alexandre, E-mail: brunet.alexandre@outlook.com [CIRAD/US 49 Analyse, Avenue Agropolis, TA B-49/01, 34398 Montpellier Cedex (France); Babre, Daniel, E-mail: Daniel.babre@cirad.fr [CIRAD/US 49 Analyse, Avenue Agropolis, TA B-49/01, 34398 Montpellier Cedex (France); Alary, Karine, E-mail: Karine.alary@cirad.fr [CIRAD/US 49 Analyse, Avenue Agropolis, TA B-49/01, 34398 Montpellier Cedex (France); Sarthou, Jean-Pierre, E-mail: sarthou@ensat.fr [ENSAT/INRA/INP UMR AGIR. BP 52627, Chemin de Borde Rouge, 31326 Castanet-Tolosan Cedex (France); Charpentier, Hubert, E-mail: Charpentier.hub@wanadoo.fr [La Boisfarderie, Brives 36100 (France); Durand, Michel, E-mail: earldeslacs@orange.fr [Le Cazals, Castanet 81 150 (France); Benada, Jaroslav, E-mail: benada@vukrom.cz [Agrotest fyto, Kromeriz Institute, Havlíckova 2787, 76701 Kromeriz (Czech Republic); Henry, Marc, E-mail: henry@unistra.fr [UMR CNRS/UdS 7140, Université de Strasbourg, Institut Le Bel, 4, rue Blaise Pascal, CS 90032, Strasbourg 67081 (France)

    2016-02-04

    The soil redox potential (Eh) can provide essential information to characterise soil conditions. In practice, however, numerous problems may arise regarding: (i) Eh determination in soils, especially aerobic soils, e.g. variations in the instrumentation and methodology for Eh measurement, high spatial and temporal Eh variability in soils, irreversibility of the redox reaction at the surface electrode, chemical disequilibrium; and (ii) measurement interpretation. This study aimed at developing a standardised method for redox potential measurement in soils, in order to use Eh as a soil quality indicator. This paper presents practical improvements in soil Eh measurement, especially regarding the control of electromagnetic perturbations, electrode choice and preparation, soil sample preparation (drying procedure) and soil:water extraction rate. The repeatability and reproducibility of the measurement method developed are highlighted. The use of Eh corrected at pH7, pe+pH or rH{sub 2}, which are equivalent notions, is proposed to facilitate interpretation of the results. The application of this Eh measurement method allows characterisation of soil conditions with sufficient repeatability, reproducibility and accuracy to demonstrate that conservation agriculture systems positively alter the protonic and electronic balance of soil as compared to conventional systems. - Highlights: • Electromagnetic fields can dramatically perturb soil Eh measurement. • Our method overcomes the main difficulties in soil Eh measurement. • Accurate and reproducible measurement of mean soil Eh are achieved. • Eh{sub pH7}, pe+pH and rH{sub 2} are equivalent notions characterising electron activity. • Agricultural practices alter soil protonic and electronic characteristics.

  5. The relationship between historical development and potentially toxic element concentrations in urban soils.

    Science.gov (United States)

    McIlwaine, Rebekka; Doherty, Rory; Cox, Siobhan F; Cave, Mark

    2017-01-01

    Increasing urbanisation has a direct impact on soil quality, resulting in elevated concentrations of potentially toxic elements (PTEs) in soils. This research aims to assess if soil PTE concentrations can be used as an 'urbanisation tracer' by investigating geogenic and anthropogenic source contributions and controls, and considering PTE enrichment across historical urban development zones. The UK cities of Belfast and Sheffield are chosen as study areas, where available shallow and deep concentrations of PTEs in soil are compared to identify geogenic and anthropogenic contributions to PTEs. Cluster analysis and principal component analysis are used to elucidate the main controls over PTE concentrations. Pollution indices indicate that different periods of historical development are linked to enrichment of different PTEs. Urban subdomains are identified and background values calculated using various methodologies and compared to generic site assessment criteria. Exceedances for a number of the PTEs considered suggest a potential human health risk could be posed across subdomains of both Belfast and Sheffield. This research suggests that airborne diffuse contamination from often historical sources such as traffic, domestic combustion and industrial processes contribute greatly to soil contamination within urban environments. The relationship between historical development and differing PTEs is a novel finding, suggesting that PTEs have the potential for use as 'urbanisation tracers'. The investigative methodology employed has potential applications for decision makers, urban planners, regulators and developers of urban areas. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. An Approach to Swelling Potential of Cohesive Soils: Avcilar-Esenyurt Example

    Directory of Open Access Journals (Sweden)

    Erkan Bozkurtoğlu

    2015-12-01

    Full Text Available Cohesive soil exhibits various degrees of swelling potential due to their clay contents and minerals. Many studies have been conducted to determine the degree of swelling of cohesive soil in the literature. These studies are related with the percentage of clay and colloid, plasticity index, shrinkage limit, activity, liquid limit, the water content and absorption and some of them give tables and others give graphics. In this study, the swelling potential of cohesive soil depending on liquid limit and natural water content were investigated. The graphical relation in literature was solved and a general equation between the water content and liquid limit of cohesive soil was determined for predicting swelling percentage. It is understood that the relation of swelling percentage between water content and liquid limit is not logarithmic as given in the literature, but it is an exponential equation with a -0.187w power constant N. The proposed methodology was applied to cohesive soil between Avcılar and Esenyurt. In literature classifications for swelling potential are variable and these definitions are inconsistent with each other. Whereas reliable numerical values for swelling are obtained by the proposed approach of swelling potential associated with clays water content.

  7. A unified classification model for modeling of seismic liquefaction potential of soil based on CPT.

    Science.gov (United States)

    Samui, Pijush; Hariharan, R

    2015-07-01

    The evaluation of liquefaction potential of soil due to an earthquake is an important step in geosciences. This article examines the capability of Minimax Probability Machine (MPM) for the prediction of seismic liquefaction potential of soil based on the Cone Penetration Test (CPT) data. The dataset has been taken from Chi-Chi earthquake. MPM is developed based on the use of hyperplanes. It has been adopted as a classification tool. This article uses two models (MODEL I and MODEL II). MODEL I employs Cone Resistance (q c) and Cyclic Stress Ratio (CSR) as input variables. q c and Peak Ground Acceleration (PGA) have been taken as inputs for MODEL II. The developed MPM gives 100% accuracy. The results show that the developed MPM can predict liquefaction potential of soil based on q c and PGA.

  8. Erratum: potential microbial contamination during sampling of permafrost soil assessed by tracers

    DEFF Research Database (Denmark)

    Bang-Andreasen, Toke; Schostag, Morten Dencker; Priemé, Anders

    2017-01-01

    Drilling and handling of permanently frozen soil cores without microbial contamination is of concern because contamination e.g. from the active layer above may lead to incorrect interpretation of results in experiments investigating potential and actual microbial activity in these low microbial...... biomass environments. Here, we present an example of how microbial contamination from active layer soil affected analysis of the potentially active microbial community in permafrost soil. We also present the development and use of two tracers: (1) fluorescent plastic microspheres and (2) Pseudomonas...... putida genetically tagged with Green Fluorescent Protein production to mimic potential microbial contamination of two permafrost cores. A protocol with special emphasis on avoiding microbial contamination was developed and employed to examine how far microbial contamination can penetrate into permafrost...

  9. Determination of potential management zones from soil electrical conductivity, yield and crop data.

    Science.gov (United States)

    Li, Yan; Shi, Zhou; Wu, Ci-fang; Li, Hong-yi; Li, Feng

    2008-01-01

    One approach to apply precision agriculture to optimize crop production and environmental quality is identifying management zones. In this paper, the variables of soil electrical conductivity (EC) data, cotton yield data and normalized difference vegetation index (NDVI) data in an about 15 ha field in a coastal saline land were selected as data resources, and their spatial variabilities were firstly analyzed and spatial distribution maps constructed with geostatistics technique. Then fuzzy c-means clustering algorithm was used to define management zones, fuzzy performance index (FPI) and normalized classification entropy (NCE) were used to determine the optimal cluster numbers. Finally one-way variance analysis was performed on 224 georeferenced soil and yield sampling points to assess how well the defined management zones reflected the soil properties and productivity level. The results reveal that the optimal number of management zones for the present study area was 3 and the defined management zones provided a better description of soil properties and yield variation. Statistical analyses indicate significant differences between the chemical properties of soil samples and crop yield in each management zone, and management zone 3 presented the highest nutrient level and potential crop productivity, whereas management zone 1 the lowest. Based on these findings, we conclude that fuzzy c-means clustering approach can be used to delineate management zones by using the given three variables in the coastal saline soils, and the defined management zones form an objective basis for targeting soil samples for nutrient analysis and development of site-specific application strategies.

  10. Phytodegradation potential of Erythrina crista-galli L., Fabaceae, in petroleum-contaminated soil.

    Science.gov (United States)

    de Farias, Vanessa; Maranho, Leila Teresinha; de Vasconcelos, Eliane Carvalho; da Silva Carvalho Filho, Marco Aurélio; Lacerda, Luiz Gustavo; Azevedo, Jayme Augusto Menegassi; Pandey, Ashok; Soccol, Carlos Ricardo

    2009-04-01

    This work aimed at investigating both the tolerance and the phytodegradation potential of Erythrina crista-galli L. in petroleum-contaminated soil. It consisted in analyzing E. crista-galli germination, surviving, growth, and development when cultivated at different contaminant concentrations and pollutant degradation rates. This specimen was selected because it presented a special behavior among others also exposed to petroleum in an accident that occurred in the Araucaria region (south of Brazil), resulting in a four-million-liter oil spill. The experiment was carried out in a greenhouse containing non-contaminated soil (NCS), vegetated contaminated soil (VCS), and non-vegetated contaminated soil (NVCS) at the following petroleum concentrations: 25 g kg(-1) (VCS-25), 50 g kg(-1) (VCS-50), and 75 g kg(-1) (VCS-75). After 60 days, the soil samples were analyzed by gas chromatography. Germination was more and more evident as higher petroleum concentrations were observed. The surviving rates of groups NCS, VCS-25, VCS-50, and VCS-75 were 64%, 70%, 61%, and 96%, respectively. The VCS group growth was reduced when compared to the control group (NCS). The individuals exposed to petroleum pollution presented differences in the anatomic structure of their roots when compared to the NCS group. It was observed that the petroleum degradation rate was higher for VCS group than for NVCS. E. crista-galli is potentially recommended for petroleum-contaminated soils because of its positive association in the presence of contamination.

  11. Nitrous oxide production and consumption potential in an agricultural and a forest soil

    DEFF Research Database (Denmark)

    Yu, Kewei; Struwe, Sten; Kjøller, Annelise

    2008-01-01

    Both a laboratory incubation experiment using soils from an agricultural field and a forest and field measurements at the same locations were conducted to determine nitrous oxide (N2O) production and consumption (reduction) potentials using the acetylene (C2H2) inhibition technique. Results from...... the laboratory experiment show that the agricultural soil had a stronger N2O reduction potential than the forest soil, as indicated by the N2O/N2 ratio in denitrification products. Without C2H2 inhibition, N2O could reach a maximum concentration of 51 and 296 ppmv in headspace of the agricultural and forest soil...... slurries, respectively. Addition of glucose decreased the maximum N2O concentration to 22 ppmv in headspace of the agricultural soil slurries, but increased to 520 ppmv in the forest soil slurries. Addition of exogenous N2O did not change such N2O accumulation maxima during the incubations. The field...

  12. Potential application of biocover soils to landfills for mitigating toluene emission.

    Science.gov (United States)

    Su, Yao; Pei, Junshen; Tian, Baohu; Fan, Fengxi; Tang, Mengling; Li, Wei; He, Ruo

    2015-12-15

    Biocover soils have been demonstrated to be a good alternative cover material to mitigate CH4 emission from landfills. To evaluate the potential of biocover soil in mitigating emissions of non-methane volatile organic compounds (NMVOCs) from landfills, simulated cover soil columns with the influx of toluene (chosen as typical of NMVOCs) concentrations of 102-1336 mg m(-3) in the presence or absence of the major landfill gas components (i.e., CH4 and CO2) were conducted in this study. In the two experimental materials (waste biocover soils (WBS) and landfill cover soils (LCS)), higher toluene reduction was observed in WBS with respect to LCS. After the introduction of landfill gas, an increase of microbial diversity and relative abundance of toluene-degrading bacteria and methanotrophs occurred in WBS. To illustrate the role of toluene-degrading activity in mitigating toluene emissions through landfill covers, an analytical model was developed by incorporating the steady-state vapor transport with the first-order kinetics of aerobic biodegradation limited by O2 availability. This study demonstrated that biocover soils have great potential in applying to landfills for mitigating toluene emission to the atmosphere. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Potential of Polycyclic Aromatic Hydrocarbon-Degrading Bacterial Isolates to Contribute to Soil Fertility

    Science.gov (United States)

    Chirima, George Johannes

    2016-01-01

    Restoration of polycyclic aromatic hydrocarbon- (PAH-) polluted sites is presently a major challenge in agroforestry. Consequently, microorganisms with PAH-degradation ability and soil fertility improvement attributes are sought after in order to achieve sustainable remediation of polluted sites. This study isolated PAH-degrading bacteria from enriched cultures of spent automobile engine-oil polluted soil. Isolates' partial 16S rRNA genes were sequenced and taxonomically classified. Isolates were further screened for their soil fertility attributes such as phosphate solubilization, atmospheric nitrogen fixation, and indoleacetic acid (IAA) production. A total of 44 isolates were obtained and belong to the genera Acinetobacter, Arthrobacter, Bacillus, Flavobacterium, Microbacterium, Ochrobactrum, Pseudomonas, Pseudoxanthomonas, Rhodococcus, and Stenotrophomonas. Data analysed by principal component analysis showed the Bacillus and Ochrobactrum isolates displayed outstanding IAA production. Generalized linear modelling statistical approaches were applied to evaluate the contribution of the four most represented genera (Pseudomonas, Acinetobacter, Arthrobacter, and Rhodococcus) to soil fertility. The Pseudomonas isolates were the most promising in all three soil fertility enhancement traits evaluated and all isolates showed potential for one or more of the attributes evaluated. These findings demonstrate a clear potential of the isolates to participate in restorative bioremediation of polluted soil, which will enhance sustainable agricultural production and environmental protection. PMID:27774456

  14. Potential of hyperspectral remote sensing for field scale soil mapping and precision agriculture applications

    Directory of Open Access Journals (Sweden)

    Raffaele Casa

    2012-10-01

    Full Text Available Mapping within-field variation in soil properties opens up the possibility of employing variable agronomic management and precision farming technologies with potential environmental and economic benefits. However, the excessive cost of systematic direct soil sampling severely constrains the practical feasibility of site specific management based on soil variability information. Remote sensing offers a cost effective and efficient means for gathering a great deal of information on soil properties. The aim of the present work was to assess the potential of satellite hyperspectral imagery for the mapping of soil properties and the tilled layer of agricultural fields, in the context of precision agriculture applications. CHRIS-PROBA satellite images were acquired over two bare soil fields and their capability to provide estimates of soil texture and soil organic matter (SOM at the field scale was assessed. Partial least squares regression (PLSR models were developed on datasets spatially independent from those used for validation. Clay and sand could be estimated with intermediate accuracy, with values of RPD (ratio of performance to deviation higher than 1.4. Root mean squared error (RMSE values of 3.7 and 5.2 were obtained for clay in the two fields respectively. SOM estimates were not satisfactory, probably because of the limited range of spatial variation in the studied fields. Maps of uniform soil zones were obtained from measured and estimates soil texture data by means of fuzzy c-means classification. The resulting maps were then used for the parameterization of a simple water balance model, i.e. CropWat8.0, in order to simulate and compare uniform and variable-rate irrigation strategies. Simulation results suggest that site-specific irrigation allows to reduce significantly water losses by deep percolation, which occur when irrigation scheduling and volumes are calculated on the basis of average field soil properties. The present paper

  15. Survival of Dermatophilus congolensis in tropical clay soils submitted to different water potentials.

    Science.gov (United States)

    Martinez, D; Prior, P

    1991-10-01

    The survival of a rifampicin-resistant mutant of Dermatophilus congolensis in vertisol and oxisol soils from Guadeloupe and in their constitutive clays was studied using a pneumatic device for controlling water potentials (pF). Experiments were carried out at two pF values simulating the wet season and the dry season. Survival time depended on the type of soil and its water content. Organic matter had a protective effect on the microorganism in oxisol but not in vertisol. The pathogenicity of D. congolensis was preserved in the soils which could therefore act as temporary reservoirs of this pathogen. Long-term survival of this organism in soils mixed with water suggests that ponds and dipping tanks may constitute sources of infection for cattle.

  16. Reduced greenhouse gas mitigation potential of no-tillage soils through earthworm activity.

    Science.gov (United States)

    Lubbers, Ingrid M; van Groenigen, Kees Jan; Brussaard, Lijbert; van Groenigen, Jan Willem

    2015-09-04

    Concerns about rising greenhouse gas (GHG) concentrations have spurred the promotion of no-tillage practices as a means to stimulate carbon storage and reduce CO2 emissions in agro-ecosystems. Recent research has ignited debate about the effect of earthworms on the GHG balance of soil. It is unclear how earthworms interact with soil management practices, making long-term predictions on their effect in agro-ecosystems problematic. Here we show, in a unique two-year experiment, that earthworm presence increases the combined cumulative emissions of CO2 and N2O from a simulated no-tillage (NT) system to the same level as a simulated conventional tillage (CT) system. We found no evidence for increased soil C storage in the presence of earthworms. Because NT agriculture stimulates earthworm presence, our results identify a possible biological pathway for the limited potential of no-tillage soils with respect to GHG mitigation.

  17. Impact of Saw Dust Application on the Distribution of Potentially Toxic Metals in Contaminated Soil.

    Science.gov (United States)

    Awokunmi, Emmmanuel E

    2017-10-16

    The need to develop an approach for the reclamation of contaminated site using locally available agricultural waste has been considered. The present study investigated the application of sawdust as an effective amendment in the immobilization of potentially toxic metals (PTMs) by conducting a greenhouse experiment on soil collected from an automobile dumpsite. The amended and non-amended soil samples were analyzed for their physicochemical parameters and sequential extraction of PTMs. The results revealed that application of amendment had positive impact on the physicochemical parameters as organic matter content and cation exchange capacity increased from 12.1% to 12.8% and 16.4 to 16.8 meq/100 g respectively. However, the mobility and bioavalability of these metals was reduced as they were found to be distributed mostly in the non-exchangeable phase of soil. Therefore, application of sawdust successfully immobilized PTMs and could be applied for future studies in agricultural soil reclamation.

  18. Carbon storage capacity of semi-arid grassland soils and sequestration potentials in northern China.

    Science.gov (United States)

    Wiesmeier, Martin; Munro, Sam; Barthold, Frauke; Steffens, Markus; Schad, Peter; Kögel-Knabner, Ingrid

    2015-10-01

    Organic carbon (OC) sequestration in degraded semi-arid environments by improved soil management is assumed to contribute substantially to climate change mitigation. However, information about the soil organic carbon (SOC) sequestration potential in steppe soils and their current saturation status remains unknown. In this study, we estimated the OC storage capacity of semi-arid grassland soils on the basis of remote, natural steppe fragments in northern China. Based on the maximum OC saturation of silt and clay particles semi-arid environments induced by intensive land use is largely irreversible. Observed SOC increases after improved land management mainly result in an accumulation of labile SOC prone to land use/climate changes and therefore cannot be regarded as contribution to long-term OC sequestration. © 2015 John Wiley & Sons Ltd.

  19. Uncertainties on Root C Turnover and Decomposition and its Impact on Soil C Sequestration Potential

    Science.gov (United States)

    Matamala, R.; Gonzalez-Meler, M. A.; Jastrow, J. D.

    2005-12-01

    Roots provide a path for movement of carbon and energy from plant canopies to soils; thus, root production and turnover directly impact the biogeochemical cycle of C and nutrients in terrestrial ecosystems. Uncertainties in estimates of production, mortality and decomposition of roots prevent proper quantification of net primary productivity (NPP), belowground C allocation and inputs to soil organic matter. Our study compares the ecosystem C sequestration potential of two distinct forest types, a pine and a sweetgum forest, growing under FACE (Free Air CO2-Enrichment) conditions that allow for the use of 13CO2 as a tracer in the tissues and soils. Using this technique root C turnover measurements have showed that although fine roots have often been assumed to have MRT of about one year, the MRT of the fine root C varies from 1 to 9 years depending on root diameter and tree species. The relative importance of a slow or a fast root C turnover is shown on the C accrual rate of the soil, slow root turnover rates appears to reduce the sequestration potential of C in soil supporting pine trees, while fast root C turnover in a sweetgum forest sustained significant increases in soil C after being exposed to elevated CO2 for five to six years. The rate of root decomposition and root inputs are calculated for both forest types and compared with the rate of soil organic matter accrual. Our results suggest that C sequestration in soils is strongly affected by root production and the MRT of C of the root system.

  20. Potential soil moisture products from the aquarius radiometer and scatterometer using an observing system simulation experiment

    Directory of Open Access Journals (Sweden)

    Y. Luo

    2013-02-01

    Full Text Available Using an observing system simulation experiment (OSSE, we investigate the potential soil moisture retrieval capability of the National Aeronautics and Space Administration (NASA Aquarius radiometer (L-band 1.413 GHz and scatterometer (L-band, 1.260 GHz. We estimate potential errors in soil moisture retrievals and identify the sources that could cause those errors. The OSSE system includes (i a land surface model in the NASA Land Information System, (ii a radiative transfer and backscatter model, (iii a realistic orbital sampling model, and (iv an inverse soil moisture retrieval model. We execute the OSSE over a 1000 × 2200 km2 region in the central United States, including the Red and Arkansas river basins. Spatial distributions of soil moisture retrieved from the radiometer and scatterometer are close to the synthetic truth. High root mean square errors (RMSEs of radiometer retrievals are found over the heavily vegetated regions, while large RMSEs of scatterometer retrievals are scattered over the entire domain. The temporal variations of soil moisture are realistically captured over a sparely vegetated region with correlations 0.98 and 0.63, and RMSEs 1.28% and 8.23% vol/vol for radiometer and scatterometer, respectively. Over the densely vegetated region, soil moisture exhibits larger temporal variation than the truth, leading to correlation 0.70 and 0.67, respectively, and RMSEs 9.49% and 6.09% vol/vol respectively. The domain-averaged correlations and RMSEs suggest that radiometer is more accurate than scatterometer in retrieving soil moisture. The analysis also demonstrates that the accuracy of the retrieved soil moisture is affected by vegetation coverage and spatial aggregation.

  1. Potential Soil Moisture Products from the Aquarius Radiometer and Scatterometer Using an Observing System Simulation Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Yan [I.M. Systems Group at NOAA/NCEP/EMC; Feng, Xia [George Mason University; Houser, Paul [George Mason University; Anantharaj, Valentine G [ORNL; Fan, Xingang [Western Kentucky University, Bowling Green; De Lannoy, Gabrielle [Ghent University, Belgium; Zhan, Xiwu [NOAA/NESDIS Center for Satellite Applications and Research; Dabbiru, Lalitha [Mississippi State University (MSU)

    2013-01-01

    Using an observing system simulation experiment (OSSE), we investigate the potential soil moisture retrieval capability of the National Aeronautics and Space Administration (NASA) Aquarius radiometer (L-band 1.413 GHz) and scatterometer (L-band, 1.260 GHz). We estimate potential errors in soil moisture retrievals and identify the sources that could cause those errors. The OSSE system includes (i) a land surface model in the NASA Land Information System, (ii) a radiative transfer and backscatter model, (iii) a realistic orbital sampling model, and (iv) an inverse soil moisture retrieval model. We execute the OSSE over a 1000 2200 km2 region in the central United States, including the Red and Arkansas river basins. Spatial distributions of soil moisture retrieved from the radiometer and scatterometer are close to the synthetic truth. High root mean square errors (RMSEs) of radiometer retrievals are found over the heavily vegetated regions, while large RMSEs of scatterometer retrievals are scattered over the entire domain. The temporal variations of soil moisture are realistically captured over a sparely vegetated region with correlations 0.98 and 0.63, and RMSEs 1.28% and 8.23% vol/vol for radiometer and scatterometer, respectively. Over the densely vegetated region, soil moisture exhibits larger temporal variation than the truth, leading to correlation 0.70 and 0.67, respectively, and RMSEs 9.49% and 6.09% vol/vol respectively. The domain-averaged correlations and RMSEs suggest that radiometer is more accurate than scatterometer in retrieving soil moisture. The analysis also demonstrates that the accuracy of the retrieved soil moisture is affected by vegetation coverage and spatial aggregation.

  2. Can assessing for potential contribution of soil organic and inorganic components for butachlor sorption be improved?

    Science.gov (United States)

    He, Yan; Liu, Zhongzhen; Zhang, Jian; Wang, Haizhen; Shi, Jiachun; Xu, Jianming

    2011-01-01

    Sorption of butachlor to various types of common soil components was investigated. Six pure minerals (montmorillonite [Mont], kaolinite [Kaol], Ca homoionic montmorillonite [Ca-Mont] and kaolinite [Ca-Kaol], amorphous hydrated Al and Fe oxides [AHOs-Al, AHOs-Fe]), four soil alkali-extractable pure humic acids (HAs), and the four corresponding HAs originated real unmodified and HO-treated soils were selected as the representative sorbents. Results showed that the HAs played a crucial role, and clay minerals (especially Mont) also showed an important effect in butachlor sorption. The AHOs may likely influence only in a mediator way by enhancing the availability of sorption domains of HAs. By removing 78% (on average) of the total organic carbon (TOC) from the soils with HO, the content ratio of clay to TOC (RCO) increased by an average of 367% and became >60. This change simultaneously decreased the sorption capacity of soils (40%, on average). Considering that the surface sorption domain on clay minerals may be highly exposed and more competitive after the partial removal of soil organic matter (SOM), this reaffirmed the potential contribution from clay minerals. It can thus be inferred that in the real soil where SOM and clay minerals are associated, the coating of clay minerals may have weakened the partition function of SOM or blocked some sorption domain within SOM, resulting in a decreased sorption of butachlor. Therefore, clay minerals, especially 2:1 type expanding minerals, may play a dual function vs. SOM content for the sorption of butachlor in soil. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  3. The potential of remediation of soils affected by salt using halophytes

    Science.gov (United States)

    Shaygan, Mandana; Mulligan, David; Baumgartl, Thomas

    2017-04-01

    Evaporation ponds containing saline waters may cause soil salinization in the vicinity of these ponds through seeping and leaching of pond water through the embankment. Native set tolerant vegetation like halophytes may assist in the revegetation and rehabilitation of these salt affected soils. As native vegetation for this study of brine affected land native halophytes species were selected including Tecticornia pergranulata, Sclerolaena longicuspis and Frankenia serpyllifoli. Soil samples from adjacent bare and vegetated areas of brine affected land were analysed to assess the physico-chemical properties associated with the vegetation cover. Salt contents of the halophytes, plant bioaccumulation, bioconcentration and translocation factors were measured to evaluate the remediation capacity of the species. The hypothesis was tested whether the halophytes are able to reduce the salt concentrations and as a consequence the salinity (and sodicity) of the soil. The examined halophytes were associated with a reduction in salinity and sodality by an average of 38.5% and 33% in the top 10 cm of the soil, respectively. Tecticornia pergranulata had the highest shoot Na+ content (98 g kg-1 dry weight) and higher factors for bioaccumulation (factor of 14) and translocation (factor of 23) for Na+ and indicated the higher remediation potential of this species. Despite the potentially successful application of this species for remediation, halophytes are in general not able to reduce the salt content within the landscape to create a condition for the growth of glycophytes particularly on a short-term time scale. However, the salt affected land can be revegetated by halophytes, and halophytes probably provide a stable vegetation cover for the landscape in ecological succession. The results also showed that a greater salt leaching potential is likely linked to soil physical parameters and most likely achievable through higher soil hydraulic conductivity which is required for

  4. Does amyl nitrite have a role in the management of pre-hospital mass casualty cyanide poisoning?

    Science.gov (United States)

    Lavon, Ophir; Bentur, Yedidia

    2010-07-01

    Amyl nitrite has been recommended as a cyanide antidote for several decades. Its antidotal properties were initially attributed to induction of methemoglobin and later to a nitric oxide mediated hemodynamic effect. The ease of administration and alleged rapid clinical effect would recommend its wide use in the pre-hospital management of mass casualty cyanide poisoning; yet there are concerns regarding the use of amyl nitrite for this indication. Review the data on amyl nitrite in cyanide poisoning and evaluate its efficacy and safety in mass casualty cyanide poisoning. A literature search utilizing PubMed, Toxnet, textbooks in toxicology and pharmacology, and the bibliographies of the articles retrieved identified 17 experimental studies and human reports on the use of amyl nitrite in cyanide poisoning, and 40 additional articles on amyl nitrite's properties and adverse effects. One paper was excluded as it was a conference abstract with limited data. The antidotal properties of amyl nitrite were attributed initially to induction of methemoglobinemia and later to nitric oxide mediated vasodilation. Animal studies on the use of amyl nitrite in cyanide poisoning are limited, and their results are inconsistent, which makes their extrapolation to humans questionable. Clinical reports are limited in number and the part played by amyl nitrite relative to the other treatments administered (e.g. life support, sodium nitrite, and sodium thiosulfate) is unclear. Amyl nitrite can be associated with potentially serious adverse reactions such as hypotension, syncope, excessive methemoglobinemia, and hemolysis in G6PD deficient patients. These effects are more pronounced in young children, in the elderly, and in patients with cardiac and pulmonary disorders. Dose regimen. The method of administration of amyl nitrite (breaking pearls into gauze or a handkerchief and applying it intermittently to the victim's nose and mouth for a few minutes) is not easily controlled, might result

  5. Relevance of Radiocaesium Interception Potential (RIP) on a worldwide scale to assess soil vulnerability to 137Cs contamination

    NARCIS (Netherlands)

    Vandebroek, L.; Hees, Van M.; Delvaux, B.; Spaargaren, O.; Thiry, Y.

    2012-01-01

    The extent of radiocaesium retention in soil is important to quantify the risk of further foodchain contamination. The Radiocaesium Interception Potential (RIP – Cremers et al., 1988, Nature 335, 247–249) is an intrinsic soil parameter which can be used to categorize soils or minerals in terms of

  6. Potential effect of changing soil temperature within an integrated biophysical-hydrological modelling system

    Science.gov (United States)

    Muerth, Markus; Hank, Tobias; Mauser, Wolfram

    2010-05-01

    The projection of potential impacts of recent and future climate change on the ecological and geophysical condition of the land surface requires both, the scientific research into the processes triggered by a changing climate, as well as the analysis of the spatial and temporal patterns induced by altering climatic conditions. In general, the potential changes and future distribution of land surface properties (e.g. soil moisture) is investigated in modelling studies. Complex land surface models for regional change detection are typically driven by data from complex climate models. Consequently, the uncertainty of the land surface model results is strongly influenced through the bias and uncertainty inherent to the atmospheric models. Therefore, the impact assessment within the multi-disciplinary research project GLOWA-Danube, which this study is part of, concentrates on two types of climate change scenarios: Uni- and bi-directional coupling of the land surface model with regional climate models ("dynamic downscaling") on one hand, and stochastic rearrangement of climate stations data based on predefined trends in temperature and precipitation ("statistical downscaling") on the other. This allows for profound "what if" impact assessment, based on the historic climate characteristic of the investigated area, which in our case is represented by the 77,000 km2 Upper Danube basin. The water and nutrient cycles of the land surface, as well as the subsurface plant development are strongly influenced by the physical and biochemical state of the soil. Again, the biochemical processes occurring in soils are largely influenced by ambient temperature and moisture. Therefore, knowledge of the temporal and spatial patterns of soil temperature is a prerequisite for impact assessment in the field of plant growth and nutrient cycles. The biological activity at the land surface again exerts impact on soil water availability and quality. The development of the integrated biophysical

  7. Measurement of soil water potential over an extended range by polymer tensiometers: comparison with other instruments

    Science.gov (United States)

    van der Ploeg, M. J.; Gooren, H. P.; Hoogendam, R. C.; Bakker, G.; Huiskes, C.; Koopal, L. K.; Kruidhof, H.; de Rooij, G. H.

    2007-12-01

    In water scarce areas, plant growth and productivity can be severely hampered by irregular precipitation and overall water shortage. Root water uptake is mainly driven by matric potential gradients, but measurement of soil water matric potential is limited by the measurement range of water-filled tensiometers (-0.085 MPa). Other measurement techniques indirectly measure soil water potential by converting soil water content with the use of the water retention curve. In dry soils, the water content measurements may become insensitive to small variations, and consequently this conversion may lead to large errors. We developed a polymer tensiometer (POT) that is able to measure matric potentials down to -2.0 MPa. The POT consists of a solid ceramic, a stainless steel cup and a pressure transducer. The ceramic consist of a support layer and a membrane with 2 nm pore-size to prevent polymer leakage. Between the ceramic membrane and the pressure transducer a tiny chamber is located, which contains the polymer solution. The polymer's osmotic potential strongly reduces the total water potential inside the polymer tensiometer, which causes build-up of osmotic pressure. Hence, the water in the polymer tensiometer will cavitate at a much lower matric potential than the nearly pure water in a conventional tensiometer. Direct observation of the potential of soil water at different locations in the root-system will yield knowledge about the ability of a plant to take up the water under conditions of water shortage or salinity stress. With this knowledge it will be possible to adjust existing unsaturated flow models accounting for root water uptake. We tested 8 POTs in an experimental setup, where we compared matric potential measurements to TDR water content measurements, matric potentials derived from measured water contents, and matric potentials measured by water-filled tensiometers. The experimental setup consisted of two evaporation boxes, one filled with sand (97.6% sand, 1

  8. Soils

    Science.gov (United States)

    Emily Moghaddas; Ken Hubbert

    2014-01-01

    When managing for resilient forests, each soil’s inherent capacity to resist and recover from changes in soil function should be evaluated relative to the anticipated extent and duration of soil disturbance. Application of several key principles will help ensure healthy, resilient soils: (1) minimize physical disturbance using guidelines tailored to specific soil types...

  9. Nitrogen isotope fractionation during archaeal ammonia oxidation: Coupled estimates from isotopic measurements of ammonium and nitrite

    Science.gov (United States)

    Mooshammer, Maria; Stieglmeier, Michaela; Bayer, Barbara; Jochum, Lara; Melcher, Michael; Wanek, Wolfgang

    2014-05-01

    Ammonia-oxidizing archaea (AOA) are ubiquitous in marine and terrestrial environments and knowledge about the nitrogen (N) isotope effect associated with their ammonia oxidation activity will allow a better understanding of natural abundance isotope ratios, and therefore N transformation processes, in the environment. Here we examine the kinetic isotope effect for ammonia oxidation in a pure soil AOA culture (Ca. Nitrososphaera viennensis) and a marine AOA enrichment culture. We estimated the isotope effect from both isotopic signatures of ammonium and nitrite over the course of ammonia oxidation. Estimates of the isotope effect based on the change in the isotopic signature of ammonium give valuable insight, because these estimates are not subject to the same concerns (e.g., accumulation of an intermediate) as estimates based on isotopic measurements of nitrite. Our results show that both the pure soil AOA culture and a marine AOA enrichment culture have similar but substantial isotope effect during ammonia consumption (31-34 per mill; based on ammonium) and nitrite production (43-45 per mill; based on nitrite). The 15N fractionation factors of both cultures tested fell in the upper range of the reported isotope effects for archaeal and bacterial ammonia oxidation (10-41 per mill) or were even higher than those. The isotope fractionation for nitrite production was significantly larger than for ammonium consumption, indicating that (1) some intermediate (e.g., hydroxylamine) of ammonia oxidation accumulates, allowing for a second 15N fractionation step to be expressed, (2) a fraction of ammonia oxidized is lost via gaseous N forms (e.g., NO or N2O), which is 15N-enriched or (3) a fraction of ammonium is assimilated into AOA biomass, biomass becoming 15N-enriched. The significance of these mechanisms will be explored in more detail for the soil AOA culture, based on isotope modeling and isotopic measurements of biomass and N2O.

  10. A laboratory apparatus for streaming potential and resistivity measurements on soil samples.

    Science.gov (United States)

    Sheffer, M R; Reppert, P M; Howie, J A

    2007-09-01

    We describe an apparatus designed to perform streaming potential and resistivity measurements on unconsolidated soil samples. The apparatus enables the use of both unidirectional and oscillatory flow methods to measure the streaming potential coupling coefficient (C); the direct current resistivity method is used to measure the bulk resistivity (rho) of the soil sample. Measuring both of these parameters on the same sample under the same conditions enables us to properly characterize the streaming current cross-coupling coefficient (L). The apparatus is designed to test reconstituted saturated soil samples up to a maximum grain size of 9.5 mm, and hydraulic gradients from less than 0.1 up to a maximum of 4 m of H(2)Om in flow-through experiments. Excellent agreement between C values measured using the unidirectional and oscillatory flow methods validates the oscillatory flow method for unconsolidated samples.

  11. Using organic matter to increase soil fertility in Burundi: potentials and limitations

    Science.gov (United States)

    Kaboneka, Salvator

    2015-04-01

    Agriculture production in Burundi is dominated by small scale farmers (0.5 ha/household) who have only very limited access to mineral inputs. In the past, farmers have relied on fallow practices combined with farm yard manures to maintain and improve soil fertility. However, due to the high population growth and high population density (370/km²), fallow practices are nowadays no longer feasible, animal manures cannot be produced in sufficient quantities to maintain soil productivity and food insecurity has become a quasi permanent reality. Most Burundian soils are characterized by 1:1 types of clay minerals (kaolinite) and are acidic in nature. Such soils are of very low cation exchange capacity (CEC). To compare the effect of % clays and % organic matter (% C), correlations tests have been conducted between the two parameters and the CEC. It was found that in high altitude kaolinitic and acidic soils, CEC was highly correlated to % C and less correlated to % clay, suggesting that organic matter could play an important role in improving fertility and productivity of these soils. Based on these findings, additional studies have been conducted to evaluate the fertilizer and soil amendment values of animal manures (cattle, goat, chicken), and leguminous (Calliandra calothyrsus, Gliricidia sepium, Senna simea, Senna spectabilis) and non-leguminous (Tithonia diversifolia) foliar biomass. It was observed that chicken manure significantly reduces Al3+ levels in acidic soils, while Tithonia diversifolia outperforms in nutrient releases compared to the commonly known leguminous agroforestry shrubs and trees indicated above. Although the above mentioned organic sources can contribute to the soil nutrients supply, the quantities potentially available on farm are generally small. The only solution is to supplement these organic sources with other organic sources (compost, organic household waste), chemical fertilizers and mineral amendments (lime) to achieve Integrated Soil

  12. Implications of Decreased Nitrite Concentrations on Clostridium perfringens Outgrowth during Cooling of Ready-to-Eat Meats.

    Science.gov (United States)

    Myers, Megan I; Sebranek, Joseph G; Dickson, James S; Shaw, Angela M; Tarté, Rodrigo; Adams, Kristin R; Neibuhr, Steve

    2016-01-01

    Increased popularity of natural and organic processed meats can be attributed to the growing consumer demand for preservative-free foods, including processed meats. To meet this consumer demand, meat processors have begun using celery juice concentrate in place of sodium nitrite to create products labeled as no-nitrate or no-nitrite-added meat products while maintaining the characteristics unique to conventionally cured processed meats. Because of flavor limitations, natural cures with celery concentrate typically provide lower ingoing nitrite concentrations for ready-to-eat processed meats than do conventional cures, which could allow for increased growth of pathogens, such as Clostridium perfringens, during cooked product cooling such as that required by the U.S. Department of Agriculture. The objective of this study was to investigate the implications associated with reduced nitrite concentrations for preventing C. perfringens outgrowth during a typical cooling cycle used for cooked products. Nitrite treatments of 0, 50, and 100 ppm were tested in a broth system inoculated with a three-strain C. perfringens cocktail and heated with a simulated product thermal process followed by a typical cooling-stabilization process. The nitrite concentration of 50 ppm was more effective for preventing C. perfringens outgrowth than was 0 ppm but was not as effective as 100 ppm. The interaction between nitrite and temperature significantly affected (P perfringens outgrowth in both total population and number of vegetative cells. Both temperature and nitrite concentration significantly affected (P perfringens spore survival, but the interaction between nitrite and temperature did not have a significant effect (P > 0.05) on spore outgrowth. Results indicate that decreased nitrite concentrations (50 ppm) have increased potential for total C. perfringens population outgrowth during cooling and may require additional protective measures, such as faster chilling rates.

  13. Platelet inhibition by nitrite is dependent on erythrocytes and deoxygenation.

    Directory of Open Access Journals (Sweden)

    Sirada Srihirun

    Full Text Available Nitrite is a nitric oxide (NO metabolite in tissues and blood, which can be converted to NO under hypoxia to facilitate tissue perfusion. Although nitrite is known to cause vasodilation following its reduction to NO, the effect of nitrite on platelet activity remains unclear. In this study, the effect of nitrite and nitrite+erythrocytes, with and without deoxygenation, on platelet activity was investigated.Platelet aggregation was studied in platelet-rich plasma (PRP and PRP+erythrocytes by turbidimetric and impedance aggregometry, respectively. In PRP, DEANONOate inhibited platelet aggregation induced by ADP while nitrite had no effect on platelets. In PRP+erythrocytes, the inhibitory effect of DEANONOate on platelets decreased whereas nitrite at physiologic concentration (0.1 µM inhibited platelet aggregation and ATP release. The effect of nitrite+erythrocytes on platelets was abrogated by C-PTIO (a membrane-impermeable NO scavenger, suggesting an NO-mediated action. Furthermore, deoxygenation enhanced the effect of nitrite as observed from a decrease of P-selectin expression and increase of the cGMP levels in platelets. The ADP-induced platelet aggregation in whole blood showed inverse correlations with the nitrite levels in whole blood and erythrocytes.Nitrite alone at physiological levels has no effect on platelets in plasma. Nitrite in the presence of erythrocytes inhibits platelets through its reduction to NO, which is promoted by deoxygenation. Nitrite may have role in modulating platelet activity in the circulation, especially during hypoxia.

  14. Organo-mineral interactions mask the true sorption potential of biochars in soils.

    Science.gov (United States)

    Singh, Neera; Kookana, Rai S

    2009-03-01

    The sorption of carbaryl (1-naphthyl methyl carbamate) and ethion [O,O,O',O'-tetraethyl S,S'-methylene bis(phosphorodithioate)] was studied in whole soils as well as after treatment of soil with 2% hydrofluoric acid (HF) to remove paramagnetic materials and to oxidize most forms of labile carbon by photo-oxidation with high energy (UV) on ethion in soils did not follow the order of their organic carbon (OC) content, and specially their char content However, the K(oc) values in ethion was observed. However, the correlation between the K(oc) and the aromatic fraction of C after the HF/UV treatment improved significantly, reflecting the contribution of char fraction of carbon in soils towards sorption of pesticides. The increase in sorption after HF/UV treatment suggested that the sorption potential of biochars, which are expected to contribute significantly to contaminant sorption due to their high surface area, can remain masked by the organo-mineral interactions of char in whole soils. This has implications for the modification of surfaces of the freshly applied biochars in soils due to organo-mineral interactions.

  15. Exploring the Nutrient Release Potential of Organic Materials as Integrated Soil Fertility Management Components Using SAFERNAC

    NARCIS (Netherlands)

    Maro, G.P.; Mrema, J.P.; Msanya, B.M.; Janssen, B.H.; Teri, J.M.

    2014-01-01

    The aim of this study was to establish the nutrient release potential of different organic materials and assess their role in integrated soil fertility management for coffee using the new coffee yield model SAFERNAC. It involved an incubation experiment conducted at TaCRI Lyamungu Screenhouse for

  16. The potential of 2D Kalman filtering for soil moisture data assimilation

    Science.gov (United States)

    We examine the potential for parameterizing a two-dimensional (2D) land data assimilation system using spatial error auto-correlation statistics gleaned from a triple collocation analysis and the triplet of: (1) active microwave-, (2) passive microwave- and (3) land surface model-based surface soil ...

  17. Spatial Modeling of Industrial Windfall on Soils to Detect Woody Species with Potential for Bioremediation

    Science.gov (United States)

    S. Salazar; M. Mendoza; A. M. Tejeda

    2006-01-01

    A spatial model is presented to explain the concentration of heavy metals (Fe, Cu, Zn, Ni, Cr, Co and Pb), in the soils around the industrial complex near the Port of Veracruz, Mexico. Unexpected low concentration sites where then tested to detect woody plant species that may have the capability to hiperacumulate these contaminants, hence having a potential for...

  18. Unveiling the metabolic potential of two soil-derived microbial consortia selected on wheat straw

    NARCIS (Netherlands)

    Jiménez Avella, Diego; Chaves-Moreno, Diego; van Elsas, Jan Dirk

    2015-01-01

    Based on the premise that plant biomass can be efficiently degraded by mixed microbial cultures and/or enzymes, we here applied a targeted metagenomics-based approach to explore the metabolic potential of two forest soil-derived lignocellulolytic microbial consortia, denoted RWS and TWS (bred on

  19. Modelling the effects of soil water potential on growth and quality of cut chrysanthemum (Chrysanthemum morifolium)

    NARCIS (Netherlands)

    Lin, L.; Li, W.; Shao, J.; Luo, W.; Dai, J.; Yin, X.; Zhou, Y.; Zhao, C.

    2011-01-01

    A complete dynamic model was developed to describe the effects of soil water potential (WP) on the growth and external quality of standard cut chrysanthemum (Chrysanthemum morifolium) in order to optimise water management of greenhouse crops. Experiments using chrysanthemum cv. ‘Jinba’ with

  20. Processes preventing nocturnal equilibration between leaf and soil water potential in tropical savanna woody species.

    Science.gov (United States)

    Sandra Bucci; Fabian G. Scholz; Guillermo Goldstein; Frederick C. Meinzer; Jose A. Hinojosa; William A. Hoffman; Augusto C. Franco

    2004-01-01

    The impact of nocturnal water loss and recharge of stem water storage on predawn disequilibrium between leaf (ΨL) and soil (Ψ S) water potentials was studied in three dominant tropical savanna woody species in central Brazil (Cerrado). Sap flow continued throughout the night during the dry season and...

  1. Deciphering potential mechanisms of anaerobic soil disinfestation (ASD)-mediated control of Pratylenchus penetrans

    Science.gov (United States)

    Pratylenchus penetrans is a component of the apple replant disease (ARD) causal pathogen complex. The potential role for biological mechanisms contributing to ASD-mediated suppression of P. penetrans was examined in greenhouse study using orchard soil with a history of ARD. Populations of P. penetra...

  2. Lead biotransformation potential of allochthonous Bacillus sp. SKK11 with sesame oil cake in mine soil

    Science.gov (United States)

    This study was aimed at assessing the potential of allochthonous Bacillus sp. SKK11 and sesame oil cake extract for transformation of Pb in mine soil. The bacteria were isolated from a brackish environment and identified as Bacillus sp. based on partial 16S rDNA sequences. The isolate SKK11 exhibite...

  3. Quantifying the controls on potential soil production rates: a case study of the San Gabriel Mountains, California

    Science.gov (United States)

    Pelletier, Jon D.

    2017-08-01

    The potential soil production rate, i.e., the upper limit at which bedrock can be converted into transportable material, limits how fast erosion can occur in mountain ranges in the absence of widespread landsliding in bedrock or intact regolith. Traditionally, the potential soil production rate has been considered to be solely dependent on climate and rock characteristics. Data from the San Gabriel Mountains of California, however, suggest that topographic steepness may also influence potential soil production rates. In this paper I test the hypothesis that topographically induced stress opening of preexisting fractures in the bedrock or intact regolith beneath hillslopes of the San Gabriel Mountains increases potential soil production rates in steep portions of the range. A mathematical model for this process predicts a relationship between potential soil production rates and average slope consistent with published data. Once the effects of average slope are accounted for, a small subset of the data suggests that cold temperatures may limit soil production rates at the highest elevations of the range due to the influence of temperature on vegetation growth. These results suggest that climate and rock characteristics may be the sole controls on potential soil production rates as traditionally assumed but that the porosity of bedrock or intact regolith may evolve with topographic steepness in a way that enhances the persistence of soil cover in compressive-stress environments. I develop an empirical equation that relates potential soil production rates in the San Gabriel Mountains to the average slope and a climatic index that accounts for temperature limitations on soil production rates at high elevations. Assuming a balance between soil production and erosion rates on the hillslope scale, I illustrate the interrelationships among potential soil production rates, soil thickness, erosion rates, and topographic steepness that result from the feedbacks among

  4. Study of Arabian Red Sea coastal soils as potential mineral dust sources

    KAUST Repository

    Prakash, P. Jish

    2016-03-23

    Both Moderate Resolution Imaging Spectroradiometer (MODIS) and Spinning Enhanced Visible and InfraRed Imager (SEVIRI) satellite observations suggest that the narrow heterogeneous Red Sea coastal region is a frequent source of airborne dust that, because of its proximity, directly affects the Red Sea and coastal urban centers. The potential of soils to be suspended as airborne mineral dust depends largely on soil texture, moisture content, and particle size distributions. Airborne dust inevitably carries the mineralogical and chemical signature of a parent soil. The existing soil databases are too coarse to resolve the small but important coastal region. The purpose of this study is to better characterize the mineralogical, chemical and physical properties of soils from the Red Sea Arabian coastal plane, which in turn will help to improve assessment of dust effect on the Red Sea and land environmental systems and urban centers. Thirteen surface soils from the hot-spot areas of wind-blown mineral dust along the Red Sea coastal plain were sampled for analysis. Analytical methods included Optical Microscopy, X-ray diffraction (XRD), Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), Ion Chromatography (IC), Scanning Electron Microscopy (SEM), and Laser Particle Size Analysis (LPSA). We found that the Red Sea coastal soils contain major components of quartz and feldspar, as well as lesser but variable amounts of amphibole, pyroxene, carbonate, clays, and micas, with traces of gypsum, halite, chlorite, epidote and oxides. The wide range of minerals in the soil samples was ascribed to the variety of igneous and metamorphic provenance rocks of the Arabian Shield forming the escarpment to the east of the Red Sea coastal plain. The analysis revealed that the samples contain compounds of nitrogen, phosphorus and iron that are essential nutrients to marine life. The analytical results from this study will provide a valuable input into dust emission models used

  5. The Potential of Hyperspectral Patterns of Winter Wheat to Detect Changes in Soil Microbial Community Composition.

    Science.gov (United States)

    Carvalho, Sabrina; van der Putten, Wim H; Hol, W H G

    2016-01-01

    Reliable information on soil status and crop health is crucial for detecting and mitigating disasters like pollution or minimizing impact from soil-borne diseases. While infestation with an aggressive soil pathogen can be detected via reflected light spectra, it is unknown to what extent hyperspectral reflectance could be used to detect overall changes in soil biodiversity. We tested the hypotheses that spectra can be used to (1) separate plants growing with microbial communities from different farms; (2) to separate plants growing in different microbial communities due to different land use; and (3) separate plants according to microbial species loss. We measured hyperspectral reflectance patterns of winter wheat plants growing in sterilized soils inoculated with microbial suspensions under controlled conditions. Microbial communities varied due to geographical distance, land use and microbial species loss caused by serial dilution. After 3 months of growth in the presence of microbes from the two different farms plant hyperspectral reflectance patterns differed significantly from each other, while within farms the effects of land use via microbes on plant reflectance spectra were weak. Species loss via dilution on the other hand affected a number of spectral indices for some of the soils. Spectral reflectance can be indicative of differences in microbial communities, with the Renormalized Difference Vegetation Index the most common responding index. Also, a positive correlation was found between the Normalized Difference Vegetation Index and the bacterial species richness, which suggests that plants perform better with higher microbial diversity. There is considerable variation between the soil origins and currently it is not possible yet to make sufficient reliable predictions about the soil microbial community based on the spectral reflectance. We conclude that measuring plant hyperspectral reflectance has potential for detecting changes in microbial

  6. Pedotransfer functions of potentially toxic elements in tropical soils cultivated with vegetable crops.

    Science.gov (United States)

    Boim, Alexys G F; Rodrigues, Sónia M; Dos Santos-Araújo, Sabrina N; Pereira, Eduarda; Alleoni, Luís R F

    2018-02-21

    The anthropogenic input of potentially toxic elements (PTEs) from industry, agrochemicals, etc., into the environment are of great concern. Models derived from pedotransfer functions can provide estimates of the levels of PTEs based on soil attributes. Based on the importance of these models in studies in contaminated areas, we assessed the concentrations of the reactive contents of Ba, Cu, Cr, Ni, Pb, and Zn in soils cultivated with vegetable crops in the state of São Paulo, Brazil. We also evaluated the influence of chemical and physical soil attributes on their reactivity and availability. The reactive contents of PTEs represent the fraction of PTEs easily sorbed at the adsorptions sites of organic matter, iron hydroxides, or clay. This fraction can supply information about the PTE content that is more or less readily released into the soil solution. The reactive and available fraction was extracted with 0.43 M HNO 3 and 0.01 M CaCl 2 , respectively. The proportion of reactivity of metal pools decreased in the order of Ba>Zn > Cu > Pb > Ni > Cr. The empirical models were able to predict the relationship between the reactive fractions, the pseudototal content, and the soil attributes. The available concentrations of Cr, Cu, Ni, and Pb in the soils were lower than the limit of quantification, while 3% of the Ba content and 1% of the Zn content were available in the soil solution in relation to their pseudototal content, suggesting low mobility of these elements in the soil.

  7. The Carbon Sequestration Potential of Soils: Some Data from Northern Italian Regions

    Directory of Open Access Journals (Sweden)

    Ciro Gardi

    2007-06-01

    Full Text Available It is well known that soil plays, within terrestrial ecosystems, an essential role in many biogeochemical cycles and in the regulation of greenhouse gas fluxes. Less known, and often underestimated, is the importance of carbon sequestration potential of soil, especially trough humified carbon. Even within the agro-forestry practices of the Kyoto Protocol, most of the attention is devoted to the biomass carbon storage, rather than soil carbon sequestration. The highest potentialities for carbon sequestration are related to the arable lands, that accounts for the 11% of earth surface; the increase of 0.1% of organic carbon content in the 0-30 cm layer of cultivated soils, achievable with minor adjustment of agronomic practices, is equivalent to the sequestration of 5,000 millions t of carbon. On the other hand, the conversion of a grasslands into cultivated land determine, during 50-70 years, a release of 80-150 t CO2 ha-1.Within this paper the estimate of soil organic carbon of three Northern Italian regions is presented.

  8. Potential soil contaminant levels of polychlorinated dibenzodioxins and dibenzofurans at industrial facilities employing heat transfer operations

    Energy Technology Data Exchange (ETDEWEB)

    Korte, N.E.; Muhr, C.A.; Greene, D.W.

    1992-04-01

    Certain manufacturing facilities formerly used large quantities of polychlorinated biphenyl (PCB) fluids in heat transfer operations. At many of these locations, operations have also involved PCB-containing electrical equipment. Commonly, over many years of plant operations, spills and leaks have resulted in PCB soil contamination. Dioxins and furans have been associated with PCB contamination in both the technical and popular press. Consequently, the need for analyses for dioxins and furans must be evaluated at locations where soils are contaminated with PCBs. This report presents an evaluation of potential dioxin and furan soil contamination based on heat transfer operations and spills from electrical equipment. The following five scenarios were examined for dioxin and furan contamination: (1) impurities in heat transfer fluids, (2) formation during heat transfer operations, (3) pyrolysis of heat transfer fluids, (4) impurities in dielectric fluids, and (5) pyrolysis of dielectric fluids. The potential contamination with dioxins and furans was calculated and compared with a 20 ppb guideline that has been used by the Centers for Disease Control for dioxin in subsoil. The results demonstrated that dioxins are formed only under pyrolytic conditions and only from the trichlorobenzenes present in dielectric fluids. Furans are found as impurities in PCB fluids but, as with dioxins, are not formed in significant quantities except during pyrolysis. Fortunately, pyrolytic conditions involving PCB fluids and soil contamination are unlikely; therefore, analyses for dioxin and furan contamination in soils will rarely be needed.

  9. Potential application of synchronous fluorescence spectroscopy to determine benzo[a]pyrene in soil extracts

    Energy Technology Data Exchange (ETDEWEB)

    Hua Guoxiong [School of Biology, Institute for Research on the Environment and Sustainability, Devonshire Building, University of Newcastle upon Tyne, NE1 7RU (United Kingdom); Killham, Ken [Department of Plant and Soil Science, Cruickshank Building, University of Aberdeen, AB24 3UU (United Kingdom); Singleton, Ian [School of Biology, Institute for Research on the Environment and Sustainability, Devonshire Building, University of Newcastle upon Tyne, NE1 7RU (United Kingdom)]. E-mail: ian.singleton@ncl.ac.uk

    2006-01-15

    Benzo[a]pyrene (BaP) is a significant environmental pollutant and rapid, accurate methods to quantify this compound in soil for both research and environmental investigation purposes are required. In this work, solvent extracts from five contrasting soils spiked with four different polycyclic aromatic hydrocarbons (PAHs) were rapidly analysed by using a synchronous fluorescence spectroscopy (SFS) method. The SFS method was validated using HPLC with ultraviolet detection. A good correlation for the quantification of BaP in soil extracts by the two methods was observed. The detection limit of the SFS method was 1.6 x 10{sup -9} g/ml in CTAB micellar medium (7.8 mmol/l). The work demonstrates that SFS has potential as a sensitive, accurate, rapid, simple and economic methodology and an efficient alternative to HPLC for fast confirmation and quantification of BaP in complex soil extracts. - Synchronous fluorescence spectroscopy has potential as a method for confirmation of benzo[a]pyrene in soil extracts.

  10. Potential of Trichoderma spp. strains for the bioremediation of soils contaminated with petroleum

    Directory of Open Access Journals (Sweden)

    Marcia Pesántez

    2016-10-01

    Full Text Available Fungi species can degrade xenobiotic compounds contaminating the soil, including hydrocarbons. The objective of this work was to determine the potential of three strains of Trichoderma, isolated from soil contaminated with petroleum, for bioremediation. Trichoderma harzianum CCECH-Te1, Trichoderma viride CCECH-Te2 and Trichoderma psedokoningii CCECH-Te3 were included in one assay with each independent strain. The inoculum was adjusted to a concentration of 1x1010 conidia ml-1 which was applied to soil contaminated by an oil spill. After 96 days of inoculation, soil samples were taken at 10 and 15 cm depth. The content of total hydrocarbons, polycyclic aromatic hydrocarbons and heavy metals such as cadmium, nickel and lead were determined. With the data, it was calculated the percentage of removal of the analyzed compounds by each strain. At 10 cm and 15 cm depth, it was observed the removal of the compounds in percentages that reached between 47 and 69.1% in the hydrocarbons and up to 53.72% in the heavy metals. It which denoted the potential of the three strains for bioremediation in contaminated soils.   Keywords: heavy metals, polycyclic aromatic hydrocarbons, xenobiotic compounds

  11. HONO fluxes from soil surfaces: an overview

    Science.gov (United States)

    Wu, Dianming; Sörgel, Matthias; Tamm, Alexandra; Ruckteschler, Nina; Rodriguez-Caballero, Emilio; Cheng, Yafang; Pöschl, Ulrich; Weber, Bettina

    2016-04-01

    Gaseous nitrous acid (HONO) contributes up to 80% of atmospheric hydroxyl (OH) radicals and is also linked to health risks through reactions with tobacco smoke forming carcinogens. Field and modeling results suggested a large unknown HONO source in the troposphere during daytime. By measuring near ground HONO mixing ratio, up to 30% of HONO can be released from forest, rural and urban ground as well as snow surfaces. This source has been proposed to heterogeneous reactions of nitrogen dioxide (NO2) on humic acid surfaces or nitric acid photolysis. Laboratory studies showed that HONO emissions from bulk soil samples can reach 258 ng m-2 s-1 (in term of nitrogen), which corresponding to 1.1 × 1012 molecules cm-2 s-1and ˜ 100 times higher than most of the field studies, as measured by a dynamic chamber system. The potential mechanisms for soil HONO emissions include chemical equilibrium of acid-base reaction and gas-liquid partitioning between soil nitrite and HONO, but the positive correlation of HONO fluxes with pH (largest at neutral and slightly alkaline) points to the dominance of the formation process by ammonia-oxidizing bacteria (AOB). In general soil surface acidity, nitrite concentration and abundance of ammonia-oxidizing bacteria mainly regulate the HONO release from soil. A recent study showed that biological soil crusts in drylands can also emit large quantities of HONO and NO, corresponding to ˜20% of global nitrogen oxide emissions from soils under natural vegetation. Due to large concentrations of microorganisms in biological soil crusts, particularly high HONO and NO emissions were measured after wetting events. Considering large areas of arid and arable lands as well as peatlands, up to 70% of global soils are able to emitting HONO. However, the discrepancy between large soil HONO emissions measured in lab and low contributions of HONO flux from ground surfaces in field as well as the role of microorganisms should be further investigated.

  12. Carbon-Fiber Nitrite Microsensor for In Situ Biofilm Monitoring

    Science.gov (United States)

    During nitrification, nitrite is produced as an intermediate when ammonia is oxidized to nitrate. It is well established that nitrifying biofilm are involved in nitrification episodes in chloraminated drinking water distribution systems with nitrite accumulation occurring during ...

  13. Chemically modified field effect transistors with nitrite or fluoride selectivity

    NARCIS (Netherlands)

    Antonisse, M.M.G.; Ruel, Bianca H.M.; Engbersen, Johannes F.J.; Reinhoudt, David

    1998-01-01

    Polysiloxanes with different types of polar substituents are excellent membrane materials for nitrite and fluoride selective chemically modified field effect transistors (CHEMFETs). Nitrite selectivity has been introduced by incorporation of a cobalt porphyrin into the membrane; fluoride selectivity

  14. Indigenous soil bacteria with the combined potential for hydrocarbon consumption and heavy metal resistance.

    Science.gov (United States)

    Ali, Nida; Dashti, Narjes; Al-Mailem, Dina; Eliyas, Mohamed; Radwan, Samir

    2012-03-01

    Transconjugant bacteria with combined potential for hydrocarbon utilization and heavy metal resistance were suggested by earlier investigators for bioremediation of soils co-contaminated with hydrocarbons and heavy metals. The purpose of this study was to offer evidence that such microorganisms are already part of the indigenous soil microflora. Microorganisms in pristine and oily soils were counted on nutrient agar and a mineral medium with oil as a sole carbon source, in the absence and presence of either sodium arsenate (As V), sodium arsenite (As III) or cadmium sulfate, and characterized via 16S rRNA gene sequencing. The hydrocarbon-consumption potential of individual strains in the presence and absence of heavy metal salts was measured. Pristine and oil-contaminated soil samples harbored indigenous bacteria with the combined potential for hydrocarbon utilization and As and Cd resistance in numbers up to 4 × 10⁵ CFU g⁻¹. Unicellular bacteria were affiliated to the following species arranged in decreasing order of predominance: Bacillus subtilis, Corynebacterium pseudotuberculosis, Brevibacterium linens, Alcaligenes faecalis, Enterobacter aerogenes, and Chromobacterium orangum. Filamentous forms were affiliated to Nocardia corallina, Streptomyces flavovirens, Micromonospora chalcea, and Nocardia paraffinea. All these isolates could grow on a wide range of pure aliphatic and aromatic hydrocarbons, as sole sources of carbon and energy, and could consume oil and pure hydrocarbons in batch cultures. Low As concentrations, and to a lesser extent Cd concentrations, enhanced the hydrocarbon-consumption potential by the individual isolates. There is no need for molecularly designing microorganisms with the combined potential for hydrocarbon utilization and heavy metal resistance, because they are already a part of the indigenous soil microflora.

  15. Plant trait diversity buffers variability in denitrification potential over changes in season and soil conditions.

    Science.gov (United States)

    McGill, Bonnie M; Sutton-Grier, Ariana E; Wright, Justin P

    2010-07-16

    Denitrification is an important ecosystem service that removes nitrogen (N) from N-polluted watersheds, buffering soil, stream, and river water quality from excess N by returning N to the atmosphere before it reaches lakes or oceans and leads to eutrophication. The denitrification enzyme activity (DEA) assay is widely used for measuring denitrification potential. Because DEA is a function of enzyme levels in soils, most ecologists studying denitrification have assumed that DEA is less sensitive to ambient levels of nitrate (NO(3)(-)) and soil carbon and thus, less variable over time than field measurements. In addition, plant diversity has been shown to have strong effects on microbial communities and belowground processes and could potentially alter the functional capacity of denitrifiers. Here, we examined three questions: (1) Does DEA vary through the growing season? (2) If so, can we predict DEA variability with environmental variables? (3) Does plant functional diversity affect DEA variability? The study site is a restored wetland in North Carolina, US with native wetland herbs planted in monocultures or mixes of four or eight species. We found that denitrification potentials for soils collected in July 2006 were significantly greater than for soils collected in May and late August 2006 (pmoisture, organic matter, total inorganic nitrogen, and microbial biomass--none consistently explained the pattern observed in DEA through time. There was no significant relationship between DEA and plant species richness or functional diversity. However, the seasonal variance in microbial biomass standardized DEA rates was significantly inversely related to plant species functional diversity (pplant functional diversity may support a more constant level of DEA through time, buffering the ecosystem from changes in season and soil conditions.

  16. Researches concerning nitrates and nitrites accumulation in carrots, along of the vegetation stages

    Directory of Open Access Journals (Sweden)

    Monica NEGREA

    2008-05-01

    Full Text Available The presented paper deals with the determination of nitrates and nitrites content in carrots, in different vegetation stages of the carrot culture. High nitrates and nitrites concentration in vegetables is mainly due to excessive nitrogen content in the soil system, thus deteriorating the nutritional and hygienic values of products and complicating the processing and storage. The determination was tested on carrot samples assayed from an experimental field set up near Timisoara. In experimental field, to the carrot culture was administrated different doses of fertilizers (NPK and the samples for analysis were assayed in different phases of vegetation. The obtained results indicated that the highest level of nitrate in carrots was found to the variant b3 (N150P90K90 in experimental field, who was above maximum limit allowed (LMA. Maximum limit allowed for nitrates in carrots, in accordance with ORDER No. 293/640/2001-1/2002 regarding security and quality conditions for vegetables and fresh fruits for human consumption is 400 ppm. For all other samples of carrots the nitrates level was below of LMA. The nitrite content grows in case of fertilizer administration during the whole vegetation stages of the plant. In variant N150P90K90 the nitrite content was above (LMA in carrot samples in all stages of vegetation. The nitrite content in carrots should not exceed 1-2 ppm. Nitrate and nitrite content in carrots was done with the help of High Performance Liquid Chromatography (HPLC in the Laboratory for the Measurement of Residues of the Department of Agro-techniques of the U.S.A-V.M.B in Timisoara.

  17. Variable pore connectivity model linking gas diffusivity and air-phase tortuosity to soil matric potential

    DEFF Research Database (Denmark)

    Chamindu, Deepagoda; Møldrup, Per; Schjønning, Per

    2012-01-01

    Soil-gas diffusivity (Dp/Do) and its dependency on soil matric potential (ψ) is important when taking regulative measures (based on accurate predictions) for climate gas emissions and also risk-mitigating measures (based on upper-limit predictions) of gaseous-phase contaminant emissions. Useful...... that accounts for water blockage. The X–pF relation can be linked to drained pore size to explain the lower probability of the larger but far fewer air-filled pores at lower pF effectively interconnecting and promoting gas diffusion. The model with X* = 2 and A = 0.5 proved promising for generalizing Dp...

  18. Nitrite maxima in the Northern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Sankaranarayanan, V.N.; DeSousa, S.N.; Fondekar, S.P.

    There are 2 nitrite maxima in the Northern Arabian Sea, one at the thermocline depth and the other at depths between 300 and 500 m. The 2nd maximum is more prominent in the northeastern part of the Arabian Sea. The 1st maximum is associated...

  19. Electrochemical removal of nitrite in simulated aquaculture wastewater

    African Journals Online (AJOL)

    use

    2011-11-21

    Nov 21, 2011 ... literature on aquaculture wastewater (AW), studies is more replete as AW is contaminated with toxic sub- stances like nitrite and nitrate (Lin and Wu, 1996;. Virkutyte and Jegatheesan, 2009; Virkutyte et al., 2010). The hazardous and toxic nature of nitrite is a major concern. Nitrite results in the wastewater ...

  20. Seasonal Distribution of Nitrate and Nitrite Levels in Eleme Abattoir ...

    African Journals Online (AJOL)

    MICHAEL

    should be periodic evaluation of nitrate and nitrite levels in the area. @ JASEM .... Table 6: Comparison of the levels of Nitrate and Nitrite in Surface and Groundwater in the Dry Season with WHO (1988) Standards. Unaffected ... Table 7: Calculated Ratios of Nitrate and Nitrite to WHO (1988) Guideline values. Season Ratios ...

  1. 40 CFR 721.4740 - Alkali metal nitrites.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal nitrites. 721.4740... Substances § 721.4740 Alkali metal nitrites. (a) Chemical substances and significant new use subject to reporting. (1) The category of chemical substances which are nitrites of the alkali metals (Group IA in the...

  2. The role of nitrite in nitric oxide homeostasis

    DEFF Research Database (Denmark)

    Jensen, Frank Bo

    2009-01-01

    Nitrite is endogenously produced as an oxidative metabolite of nitric oxide, but it also functions as a NO donor that can be activated by a number of cellular proteins under hypoxic conditions. This article discusses the physiological role of nitrite and nitrite-derived NO in blood flow regulatio...

  3. Validating potential toxicity assays to assess petroleum hydrocarbon toxicity in polar soil.

    Science.gov (United States)

    Harvey, Alexis Nadine; Snape, Ian; Siciliano, Steven Douglas

    2012-02-01

    Potential microbial activities are commonly used to assess soil toxicity of petroleum hydrocarbons (PHC) and are assumed to be a surrogate for microbial activity within the soil ecosystem. However, this assumption needs to be evaluated for frozen soil, in which microbial activity is limited by liquid water (θ(liquid)). Influence of θ(liquid) on in situ toxicity was evaluated and compared to the toxicity endpoints of potential microbial activities using soil from an aged diesel fuel spill at Casey Station, East Antarctica. To determine in situ toxicity, gross mineralization and nitrification rates were determined by the stable isotope dilution technique. Petroleum hydrocarbon-contaminated soil (0-8,000 mg kg(-1)), packed at bulk densities of 1.4, 1.7, and 2.0 g cm(-3) to manipulate liquid water content, was incubated at -5°C for one, two, and three months. Although θ(liquid) did not have a significant effect on gross mineralization or nitrification, gross nitrification was sensitive to PHC contamination, with toxicity decreasing over time. In contrast, gross mineralization was not sensitive to PHC contamination. Toxic response of gross nitrification was comparable to potential nitrification activity (PNA) with similar EC25 (effective concentration causing a 25% effect in the test population) values determined by both measurement endpoints (400 mg kg(-1) for gross nitrification compared to 200 mg kg(-1) for PNA), indicating that potential microbial activity assays are good surrogates for in situ toxicity of PHC contamination in polar regions. Copyright © 2011 SETAC.

  4. Long-Term Warming Alters Carbohydrate Degradation Potential in Temperate Forest Soils.

    Science.gov (United States)

    Pold, Grace; Billings, Andrew F; Blanchard, Jeff L; Burkhardt, Daniel B; Frey, Serita D; Melillo, Jerry M; Schnabel, Julia; van Diepen, Linda T A; DeAngelis, Kristen M

    2016-11-15

    As Earth's climate warms, soil carbon pools and the microbial communities that process them may change, altering the way in which carbon is recycled in soil. In this study, we used a combination of metagenomics and bacterial cultivation to evaluate the hypothesis that experimentally raising soil temperatures by 5°C for 5, 8, or 20 years increased the potential for temperate forest soil microbial communities to degrade carbohydrates. Warming decreased the proportion of carbohydrate-degrading genes in the organic horizon derived from eukaryotes and increased the fraction of genes in the mineral soil associated with Actinobacteria in all studies. Genes associated with carbohydrate degradation increased in the organic horizon after 5 years of warming but had decreased in the organic horizon after warming the soil continuously for 20 years. However, a greater proportion of the 295 bacteria from 6 phyla (10 classes, 14 orders, and 34 families) isolated from heated plots in the 20-year experiment were able to depolymerize cellulose and xylan than bacterial isolates from control soils. Together, these findings indicate that the enrichment of bacteria capable of degrading carbohydrates could be important for accelerated carbon cycling in a warmer world. The massive carbon stocks currently held in soils have been built up over millennia, and while numerous lines of evidence indicate that climate change will accelerate the processing of this carbon, it is unclear whether the genetic repertoire of the microbes responsible for this elevated activity will also change. In this study, we showed that bacteria isolated from plots subject to 20 years of 5°C of warming were more likely to depolymerize the plant polymers xylan and cellulose, but that carbohydrate degradation capacity is not uniformly enriched by warming treatment in the metagenomes of soil microbial communities. This study illustrates the utility of combining culture-dependent and culture-independent surveys of

  5. Soil Organic Carbon Sequestration Potential in Nectarine Orchards under Different Reclamation Systems

    Institute of Scientific and Technical Information of China (English)

    Yixiang WANG; Boqi WENG; Jing YE; Chengji WANG; Cenwei LIU; Yanchun LI

    2017-01-01

    The Red Soil Hilly Region in South China,where there is a high capacity of carbon (C),and the land use and vegetation cover change greatly,is an important ecological area in the world,and has an important impact on the global carbon cycle and the seasonal fluctuation of atmospheric CO2.To better evaluate the effects of reclamation systems in orchards converted from grasslands on soil carbon sequestration,we investigated soil organic carbon (SOC) content and stable C isotope (δ13C) composition in three nectarine orchards at Yuchi Experimental Station in South China.Compared with the sloping clean tillage orchard and terraced clean tillage orchard,SOC content in the terraced orchard with grass cover was increased by 14.90% to 38.49%,and 7.40% to15.33%,respectively.During the 14 years after orchard establishment,the soil organic matter sources influenced both δ13C distribution with depth and carbon replacement.SOC turnover of the upper soil layer in the terraced orchard with grass cover (a mean 63.05% of replacement in the 20 cm after 14 years) was 1.59 and 1.41 times larger than that of the sloping clean tillage orchard and terraced clean tillage orchard under subtropical conditions,respectively.The equilibrium value of soil organic carbon in the three treatments ranged from 16.067 to 25.608 g/kg under the experimental conditions.The equilibrium value of soil organic carbon in the surface layer under grass cover was 54.801 t/hm2,and the carbon sequestration potential was 24.695 1 t/hm2.

  6. Determination of potential management zones from soil electrical conductivity, yield and crop data*

    Science.gov (United States)

    Li, Yan; Shi, Zhou; Wu, Ci-fang; Li, Hong-yi; Li, Feng

    2008-01-01

    One approach to apply precision agriculture to optimize crop production and environmental quality is identifying management zones. In this paper, the variables of soil electrical conductivity (EC) data, cotton yield data and normalized difference vegetation index (NDVI) data in an about 15 ha field in a coastal saline land were selected as data resources, and their spatial variabilities were firstly analyzed and spatial distribution maps constructed with geostatistics technique. Then fuzzy c-means clustering algorithm was used to define management zones, fuzzy performance index (FPI) and normalized classification entropy (NCE) were used to determine the optimal cluster numbers. Finally one-way variance analysis was performed on 224 georeferenced soil and yield sampling points to assess how well the defined management zones reflected the soil properties and productivity level. The results reveal that the optimal number of management zones for the present study area was 3 and the defined management zones provided a better description of soil properties and yield variation. Statistical analyses indicate significant differences between the chemical properties of soil samples and crop yield in each management zone, and management zone 3 presented the highest nutrient level and potential crop productivity, whereas management zone 1 the lowest. Based on these findings, we conclude that fuzzy c-means clustering approach can be used to delineate management zones by using the given three variables in the coastal saline soils, and the defined management zones form an objective basis for targeting soil samples for nutrient analysis and development of site-specific application strategies. PMID:18196615

  7. Denitrification potential and its relation to organic carbon quality in three coastal wetland soils.

    Science.gov (United States)

    Dodla, Syam K; Wang, Jim J; DeLaune, Ron D; Cook, Robert L

    2008-12-15

    Capacity of a wetland to remove nitrate through denitrification is controlled by its physico-chemical and biological characteristics. Understanding these characteristics will help better to guide beneficial use of wetlands in processing nitrate. This study was conducted to determine the relationship between soil organic carbon (SOC) quality and denitrification rate in Louisiana coastal wetlands. Composite soil samples of different depths were collected from three different wetlands along a salinity gradient, namely, bottomland forest swamp (FS), freshwater marsh (FM), and saline marsh (SM) located in the Barataria Basin estuary. Potential denitrification rate (PDR) was measured by acetylene inhibition method and distribution of carbon (C) moieties in organic C was determined by 13C solid-state NMR. Of the three wetlands, the FM soil profile exhibited the highest PDR on both unit weight and unit volume basis as compared to FS and SM. The FM also tended to yield higher amount of N2O as compared to the FS and SM especially at earlier stages of denitrification, suggesting incomplete reduction of NO3(-) at FM and potential for emission of N2O. Saline marsh soil profile had the lowest PDR on the unit volume basis. Increasing incubation concentration from 2 to 10 mg NO3(-)-N L(-1) increased PDR by 2 to 6 fold with the highest increase in the top horizons of FS and SM soils. Regression analysis showed that across these three wetland systems, organic C has significant effect in regulating PDR. Of the compositional C moieties, polysaccharides positively influenced denitrification rate whereas phenolics (likely phenolic adehydes and ketonics) negatively affected denitrification rate in these wetland soils. These results could have significant implication in integrated assessment and management of wetlands for treating nutrient-rich biosolids and wastewaters, non-point source agricultural runoff, and nitrate found in the diverted Mississippi River water used for coastal

  8. Biochar amendment reduces paddy soil nitrogen leaching but increases net global warming potential in Ningxia irrigation, China.

    Science.gov (United States)

    Wang, Yongsheng; Liu, Yansui; Liu, Ruliang; Zhang, Aiping; Yang, Shiqi; Liu, Hongyuan; Zhou, Yang; Yang, Zhengli

    2017-05-09

    The efficacy of biochar as an environmentally friendly agent for non-point source and climate change mitigation remains uncertain. Our goal was to test the impact of biochar amendment on paddy rice nitrogen (N) uptake, soil N leaching, and soil CH 4 and N 2 O fluxes in northwest China. Biochar was applied at four rates (0, 4.5, 9 and13.5 t ha -1 yr -1 ). Biochar amendment significantly increased rice N uptake, soil total N concentration and the abundance of soil ammonia-oxidizing archaea (AOA), but it significantly reduced the soil NO 3 - -N concentration and soil bulk density. Biochar significantly reduced NO 3 - -N and NH 4 + -N leaching. The C2 and C3 treatments significantly increased the soil CH 4 flux and reduced the soil N 2 O flux, leading to significantly increased net global warming potential (GWP). Soil NO 3 - -N rather than NH 4 + -N was the key integrator of the soil CH 4 and N 2 O fluxes. Our results indicate that a shift in abundance of the AOA community and increased rice N uptake are closely linked to the reduced soil NO 3 - -N concentration under biochar amendment. Furthermore, soil NO 3 - -N availability plays an important role in regulating soil inorganic N leaching and net GWP in rice paddies in northwest China.

  9. Stress response and potential biomarkers in spinach (Spinacia oleracea L.) seedlings exposed to soil lead.

    Science.gov (United States)

    Wang, Chengrun; Gu, Xueyuan; Wang, Xiaorong; Guo, Hongyan; Geng, Jinju; Yu, Hongxia; Sun, Jian

    2011-01-01

    Oxidative stress and biochemical responses of spinach seedlings to soil Pb stress were investigated by pot experiments. The seedlings were exposed to 0-500 mg kg(-1) extraneous Pb. After 30 days of germination, production of O(2)(-), HSP 70, HSP 60, superoxide dismutase (SOD) activities, carbonyl groups and lipid peroxidation was significantly induced by soil Pb. After 50 days, HSP 70 and HSP 60 decreased, and HSP 60 was significantly inhibited at 500 mg kg(-1). The results indicated that Pb probably induced oxidative stress and proteotoxicity to the seedlings through O(2)(-) accumulation, and that SOD, HSP 70 and HSP 60 were important defense mechanisms to alleviate the oxidative stress. It is found that O(2)(-), HSP 70 and HSP 60 were the most sensitive parameters and had the potential to act as biomarkers for early warning of soil Pb contamination. Concentrations of soil Pb, exposing time and combination of multiple parameters should be also taken into consideration when assessing soil Pb pollution by these biomarkers. Copyright © 2009 Elsevier Inc. All rights reserved.

  10. Nanoscale zero-valent iron-assisted soil washing for the removal of potentially toxic elements.

    Science.gov (United States)

    Boente, C; Sierra, C; Martínez-Blanco, D; Menéndez-Aguado, J M; Gallego, J R

    2018-02-09

    The present study focuses on soil washing enhancement via soil pretreatment with nanoscale zero-valent iron (nZVI) for the remediation of potentially toxic elements. To this end, soil polluted with As, Cu, Hg, Pb and Sb was partitioned into various grain sizes (500-2000, 125-500 and PTEs) fate, and allowed a metallurgical accounting correction considering the dilution effects caused by nanoparticle addition. As a result, remarkable recovery yields were obtained for Cu, Pb and Sb, which concentrated with the nZVI in the magnetically separated fraction (WHIMS tests) and underflow (hydrocyclone tests). In contrast, Hg, concentrated in the non-magnetic fraction and overflow respectively, while the behavior of As was unaltered by the nZVI pretreatment. All things considered, the addition of nZVI enhanced the efficiency of soil washing, particularly for larger fractions (125-2000 μm). The proposed methodology lays the foundations for nanoparticle utilization in soil washing operations. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Potential of Sentinel-1 Radar Data for the Assessment of Soil and Cereal Cover Parameters.

    Science.gov (United States)

    Bousbih, Safa; Zribi, Mehrez; Lili-Chabaane, Zohra; Baghdadi, Nicolas; El Hajj, Mohammad; Gao, Qi; Mougenot, Bernard

    2017-11-14

    The main objective of this study is to analyze the potential use of Sentinel-1 (S1) radar data for the estimation of soil characteristics (roughness and water content) and cereal vegetation parameters (leaf area index (LAI), and vegetation height (H)) in agricultural areas. Simultaneously to several radar acquisitions made between 2015 and 2017, using S1 sensors over the Kairouan Plain (Tunisia, North Africa), ground measurements of soil roughness, soil water content, LAI and H were recorded. The NDVI (normalized difference vegetation index) index computed from Landsat optical images revealed a strong correlation with in situ measurements of LAI. The sensitivity of the S1 measurements to variations in soil moisture, which has been reported in several scientific publications, is confirmed in this study. This sensitivity decreases with increasing vegetation cover growth (NDVI), and is stronger in the VV (vertical) polarization than in the VH cross-polarization. The results also reveal a similar increase in the dynamic range of radar signals observed in the VV and VH polarizations as a function of soil roughness. The sensitivity of S1 measurements to vegetation parameters (LAI and H) in the VV polarization is also determined, showing that the radar signal strength decreases when the vegetation parameters increase. No vegetation parameter sensitivity is observed in the VH polarization, probably as a consequence of volume scattering effects.

  12. Lead contamination and its potential sources in vegetables and soils of Fujian, China.

    Science.gov (United States)

    Huang, Zhi-Yong; Chen, Ting; Yu, Jiang; Qin, De-Ping; Chen, Lan

    2012-02-01

    Lead (Pb) contents and partition in soils collected from eleven vegetable-growing lands in Fujian Province, China, were investigated using a modification of the BCR (Community Bureau of Reference) sequential extraction procedure coupled with the Pb isotope ratio technique. Pb contents in Chinese white cabbage (B. Chinensis L.) grown on the lands for this study were also measured. Results showed that Pb concentrations in fifty samples of topsoil ranged from 456 to 21.5 mg kg(-1), with each mean concentration of six sampling lands exceeding the national standard (50 mg kg(-1)); while Pb concentrations in edible portions of thirty-two vegetable samples ranged from 0.009 to 2.20 mg kg(-1), with four sampling sites exceeding the national sanitary standard (0.2 mg kg(-1)). A significant correlation (r = 0.971, P metal bioavailability for plants and potential risk for human health in soils. The determination of lead isotope ratios in different chemical forms of soils by BCR sequential extraction procedures provides useful information on the Pb isotopic composition associated with different soil fractions (especially in the acid-extractable fractions), and the result is helpful for the further study on controlling and reducing Pb contamination in vegetable-growing soils. © Springer Science+Business Media B.V. 2011

  13. Potential of Sentinel-1 Radar Data for the Assessment of Soil and Cereal Cover Parameters

    Directory of Open Access Journals (Sweden)

    Safa Bousbih

    2017-11-01

    Full Text Available The main objective of this study is to analyze the potential use of Sentinel-1 (S1 radar data for the estimation of soil characteristics (roughness and water content and cereal vegetation parameters (leaf area index (LAI, and vegetation height (H in agricultural areas. Simultaneously to several radar acquisitions made between 2015 and 2017, using S1 sensors over the Kairouan Plain (Tunisia, North Africa, ground measurements of soil roughness, soil water content, LAI and H were recorded. The NDVI (normalized difference vegetation index index computed from Landsat optical images revealed a strong correlation with in situ measurements of LAI. The sensitivity of the S1 measurements to variations in soil moisture, which has been reported in several scientific publications, is confirmed in this study. This sensitivity decreases with increasing vegetation cover growth (NDVI, and is stronger in the VV (vertical polarization than in the VH cross-polarization. The results also reveal a similar increase in the dynamic range of radar signals observed in the VV and VH polarizations as a function of soil roughness. The sensitivity of S1 measurements to vegetation parameters (LAI and H in the VV polarization is also determined, showing that the radar signal strength decreases when the vegetation parameters increase. No vegetation parameter sensitivity is observed in the VH polarization, probably as a consequence of volume scattering effects.

  14. Evaluation of potential phytoremediation of chrysanthemum in soil with excess copper

    Directory of Open Access Journals (Sweden)

    Janine Farias Menegaes

    2017-02-01

    Full Text Available Minimizing the harmful effects of copper (Cu in the soil, using plants are slow and gradual, requiring the identification of species with fitorremediativa fitness for this process. Thus, the present work had as objective to evaluate the cultivation of chrysanthemum cv. Dark Fiji in soil added with Cu as promising phytoremediation. The experiment was conducted in the period from July to December 2014, in the greenhouse of the Floriculture UFSM. In a completely randomized experimental design, with five treatments composed of doses of Cu added to the soil, in the amounts of 250, 500, 750 and 1,000 mg kg-1 and control (without addition, with five replications. In two crop cycles both with duration of 104 days from the production of seedlings to harvest. Chrysanthemum cuttings were obtained from cuttings collected in the garden clonal itself, with 8 cm long, rooted in commercial substrate and transplanted into containers containing soil. They evaluated phytotechnical parameters and translocation factors of aerial part of bioaccumulation and bioconcentration factor of Cu in plant roots and metal extraction rate. It was observed that at all doses of Cu added to the soil, the plants showed low plant development and floriferous affecting its aesthetic quality in both crop cycles. The high accumulation of Cu in the roots is indicative of growing tolerance, cv. Dark Fiji in areas with excess of this, with phytoremediation potential.

  15. The influence of 10 years reduced tillage on the potential carbon mineralization of silt loam soils under a temperate climate.

    Science.gov (United States)

    D'haene, Karoline; Van den Bossche, Annemie; De Neve, Stefaan; Gabriels, Donald; Hofman, Georges

    2006-01-01

    The influence of 10 years reduced tillage (RT) on the potential carbon mineralization of the 0-5 cm layer of silt loam soils in Belgium under a temperate climate was investigated. Therefore, four fields at three locations under 10 years of RT and fields under conventional tillage (CT) with comparable crop rotation were selected. The higher % soil organic carbon in the upper layer resulted in a higher potential carbon mineralization of the RT fields. The small increase in % soil organic carbon and potential carbon mineralization of RT fields was contributed to the high soil disturbance due to incorporation of manure in the upper layer and the production of sugar beets and potatoes. Simulating ploughing by emptying and refilling the soil cores resulted mostly in a higher potential carbon mineralization. However, the differences were not significant due to the high variability in potential carbon mineralization.

  16. Evidence for the cooccurrence of nitrite-dependent anaerobic ammonium and methane oxidation processes in a flooded paddy field.

    Science.gov (United States)

    Shen, Li-Dong; Liu, Shuai; Huang, Qian; Lian, Xu; He, Zhan-Fei; Geng, Sha; Jin, Ren-Cun; He, Yun-Feng; Lou, Li-Ping; Xu, Xiang-Yang; Zheng, Ping; Hu, Bao-Lan

    2014-12-01

    Anaerobic ammonium oxidation (anammox) and nitrite-dependent anaerobic methane oxidation (n-damo) are two of the most recent discoveries in the microbial nitrogen cycle. In the present study, we provide direct evidence for the cooccurrence of the anammox and n-damo processes in a flooded paddy field in southeastern China. Stable isotope experiments showed that the potential anammox rates ranged from 5.6 to 22.7 nmol N2 g(-1) (dry weight) day(-1) and the potential n-damo rates varied from 0.2 to 2.1 nmol CO2 g(-1) (dry weight) day(-1) in different layers of soil cores. Quantitative PCR showed that the abundance of anammox bacteria ranged from 1.0 × 10(5) to 2.0 × 10(6) copies g(-1) (dry weight) in different layers of soil cores and the abundance of n-damo bacteria varied from 3.8 × 10(5) to 6.1 × 10(6) copies g(-1) (dry weight). Phylogenetic analyses of the recovered 16S rRNA gene sequences showed that anammox bacteria affiliated with "Candidatus Brocadia" and "Candidatus Kuenenia" and n-damo bacteria related to "Candidatus Methylomirabilis oxyfera" were present in the soil cores. It is estimated that a total loss of 50.7 g N m(-2) per year could be linked to the anammox process, which is at intermediate levels for the nitrogen flux ranges of aerobic ammonium oxidation and denitrification reported in wetland soils. In addition, it is estimated that a total of 0.14 g CH4 m(-2) per year could be oxidized via the n-damo process, while this rate is at the lower end of the aerobic methane oxidation rates reported in wetland soils. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  17. Analyses of soil microbial community compositions and functional genes reveal potential consequences of natural forest succession

    Science.gov (United States)

    Cong, Jing; Yang, Yunfeng; Liu, Xueduan; Lu, Hui; Liu, Xiao; Zhou, Jizhong; Li, Diqiang; Yin, Huaqun; Ding, Junjun; Zhang, Yuguang

    2015-05-01

    The succession of microbial community structure and function is a central ecological topic, as microbes drive the Earth’s biogeochemical cycles. To elucidate the response and mechanistic underpinnings of soil microbial community structure and metabolic potential relevant to natural forest succession, we compared soil microbial communities from three adjacent natural forests: a coniferous forest (CF), a mixed broadleaf forest (MBF) and a deciduous broadleaf forest (DBF) on Shennongjia Mountain in central China. In contrary to plant communities, the microbial taxonomic diversity of the DBF was significantly (P functional diversity was also highest in the DBF. Furthermore, a network analysis of microbial carbon and nitrogen cycling genes showed the network for the DBF samples was relatively large and tight, revealing strong couplings between microbes. Soil temperature, reflective of climate regimes, was important in shaping microbial communities at both taxonomic and functional gene levels. As a first glimpse of both the taxonomic and functional compositions of soil microbial communities, our results suggest that microbial community structure and function potentials will be altered by future environmental changes, which have implications for forest succession.

  18. Wastewater use in agriculture and potential effects on meso and macrofauna soil

    Directory of Open Access Journals (Sweden)

    Dinéia Tessaro

    2016-06-01

    Full Text Available ABSTRACT: The use of wastewater in agriculture has been practiced on an increasing scale over the past decades because of its fertilizing potential and the reduction in demand for surface water and groundwater. However, this practice may bring harm when performed without planning, not respecting the capacity of the soil to recycle organic waste. The most common problems are contamination of surface and groundwater via leaching and runoff, as well as accumulation of nutrients and potentially polluting elements that compromise chemical, physical and biological characteristics of the soil. The biological compartment, represented by the micro, meso and macrofauna, plays an important role in nutrient cycling, decomposition of organic matter, particle movement and transport of materials at different depths, helping to maintain soil physical and chemical characteristics. In this sense, this paper aims to discuss the effect of using different kinds of wastewater in agriculture on soil biology, highlighting strengths and weaknesses, as well as emphasizing the need to conduct investigations that enhance the positive aspects of wastewater use associated with edaphic processes.

  19. Effect of different soil water potential on leaf transpiration and on stomatal conductance in poinsettia

    Directory of Open Access Journals (Sweden)

    Jacek S. Nowak

    2013-12-01

    Full Text Available Euphorbia pulcherrima Wild.'Lilo' was grown in containers in 60% peat, 30% perlite and 10% clay (v/v mixture, with different irrigation treatments based on soil water potential. Plants were watered at two levels of drought stress: -50kPa or wilting. The treatments were applied at different stages of plant development for a month or soil was brought to the moisture stress only twice. Additionally, some plants were watered at -50 kPa during the entire cultivation period while the control plants were watered at -5kPa. Plants were also kept at maximum possible moisture level (watering at -0,5kPa or close to it (-1.OkPa through the entire growing period. Soil water potential was measured with tensiometer. Drought stress applied during entire cultivation period or during the flushing stage caused significant reduction in transpiration and conductance of leaves. Stress applied during bract coloration stage had not as great effect on the stomatal conductance and transpiration of leaves as the similar stress applied during the flushing stage. High soil moisture increased stomatal conductance and transpiration rate, respectively by 130% and 52% (flushing stage, and 72% and 150% (bract coloration stage at maximum, compared to the control.

  20. Microbial functional potential and community composition in permafrost-affected soils of the NW Canadian Arctic.

    Science.gov (United States)

    Frank-Fahle, Béatrice A; Yergeau, Etienne; Greer, Charles W; Lantuit, Hugues; Wagner, Dirk

    2014-01-01

    Permafrost-affected soils are among the most obvious ecosystems in which current microbial controls on organic matter decomposition are changing as a result of global warming. Warmer conditions in polygonal tundra will lead to a deepening of the seasonal active layer, provoking changes in microbial processes and possibly resulting in exacerbated carbon degradation under increasing anoxic conditions. To identify current microbial assemblages in carbon rich, water saturated permafrost environments, four polygonal tundra sites were investigated on Herschel Island and the Yukon Coast, Western Canadian Arctic. Ion Torrent sequencing of bacterial and archaeal 16S rRNA amplicons revealed the presence of all major microbial soil groups and indicated a local, vertical heterogeneity of the polygonal tundra soil community with increasing depth. Microbial diversity was found to be highest in the surface layers, decreasing towards the permafrost table. Quantitative PCR analysis of functional genes involved in carbon and nitrogen-cycling revealed a high functional potential in the surface layers, decreasing with increasing active layer depth. We observed that soil properties driving microbial diversity and functional potential varied in each study site. These results highlight the small-scale heterogeneity of geomorphologically comparable sites, greatly restricting generalizations about the fate of permafrost-affected environments in a warming Arctic.

  1. Microbial functional potential and community composition in permafrost-affected soils of the NW Canadian Arctic.

    Directory of Open Access Journals (Sweden)

    Béatrice A Frank-Fahle

    Full Text Available Permafrost-affected soils are among the most obvious ecosystems in which current microbial controls on organic matter decomposition are changing as a result of global warming. Warmer conditions in polygonal tundra will lead to a deepening of the seasonal active layer, provoking changes in microbial processes and possibly resulting in exacerbated carbon degradation under increasing anoxic conditions. To identify current microbial assemblages in carbon rich, water saturated permafrost environments, four polygonal tundra sites were investigated on Herschel Island and the Yukon Coast, Western Canadian Arctic. Ion Torrent sequencing of bacterial and archaeal 16S rRNA amplicons revealed the presence of all major microbial soil groups and indicated a local, vertical heterogeneity of the polygonal tundra soil community with increasing depth. Microbial diversity was found to be highest in the surface layers, decreasing towards the permafrost table. Quantitative PCR analysis of functional genes involved in carbon and nitrogen-cycling revealed a high functional potential in the surface layers, decreasing with increasing active layer depth. We observed that soil properties driving microbial diversity and functional potential varied in each study site. These results highlight the small-scale heterogeneity of geomorphologically comparable sites, greatly restricting generalizations about the fate of permafrost-affected environments in a warming Arctic.

  2. Potential microbial contamination during sampling of permafrost soil assessed by tracers

    Science.gov (United States)

    Bang-Andreasen, Toke; Schostag, Morten; Priemé, Anders; Elberling, Bo; Jacobsen, Carsten S.

    2017-02-01

    Drilling and handling of permanently frozen soil cores without microbial contamination is of concern because contamination e.g. from the active layer above may lead to incorrect interpretation of results in experiments investigating potential and actual microbial activity in these low microbial biomass environments. Here, we present an example of how microbial contamination from active layer soil affected analysis of the potentially active microbial community in permafrost soil. We also present the development and use of two tracers: (1) fluorescent plastic microspheres and (2) Pseudomonas putida genetically tagged with Green Fluorescent Protein production to mimic potential microbial contamination of two permafrost cores. A protocol with special emphasis on avoiding microbial contamination was developed and employed to examine how far microbial contamination can penetrate into permafrost cores. The quantity of tracer elements decreased with depth into the permafrost cores, but the tracers were detected as far as 17 mm from the surface of the cores. The results emphasize that caution should be taken to avoid microbial contamination of permafrost cores and that the application of tracers represents a useful tool to assess penetration of potential microbial contamination into permafrost cores.

  3. Potential microbial contamination during sampling of permafrost soil assessed by tracers.

    Science.gov (United States)

    Bang-Andreasen, Toke; Schostag, Morten; Priemé, Anders; Elberling, Bo; Jacobsen, Carsten S

    2017-02-23

    Drilling and handling of permanently frozen soil cores without microbial contamination is of concern because contamination e.g. from the active layer above may lead to incorrect interpretation of results in experiments investigating potential and actual microbial activity in these low microbial biomass environments. Here, we present an example of how microbial contamination from active layer soil affected analysis of the potentially active microbial community in permafrost soil. We also present the development and use of two tracers: (1) fluorescent plastic microspheres and (2) Pseudomonas putida genetically tagged with Green Fluorescent Protein production to mimic potential microbial contamination of two permafrost cores. A protocol with special emphasis on avoiding microbial contamination was developed and employed to examine how far microbial contamination can penetrate into permafrost cores. The quantity of tracer elements decreased with depth into the permafrost cores, but the tracers were detected as far as 17 mm from the surface of the cores. The results emphasize that caution should be taken to avoid microbial contamination of permafrost cores and that the application of tracers represents a useful tool to assess penetration of potential microbial contamination into permafrost cores.

  4. The impacts of drying and rewetting cycles on potential methanogenesis in wetland soils

    Science.gov (United States)

    Kannenberg, S.; Ludwig, S.; Nelson, L.; Rich, H.; Spawn, S.; Porterfield, J.; Schade, J. D.

    2012-12-01

    have the highest potential to quickly initiate high levels of methane production. This may be the result of suppression of methanogens under high NO3 due to competition with denitrifying bacteria. Moreover, once methane production began, intermittently saturated sites showed higher methane flux than permanently wet sites. Results overall suggest that ephemeral wetlands that show extensive seasonal rewetting of soils on their margins are likely to produce methane at high rates, with potentially significant implications as a positive feedback on global climate change, especially with predicted changes in precipitation patterns.

  5. Molecular Characterization of Lactobacillus plantarum DMDL 9010, a Strain with Efficient Nitrite Degradation Capacity

    Science.gov (United States)

    Fei, Yong-tao; Liu, Dong-mei; Luo, Tong-hui; Chen, Gu; Wu, Hui; Li, Li; Yu, Yi-gang

    2014-01-01

    Nitrites commonly found in food, especially in fermented vegetables, are potential carcinogens. Therefore, limiting nitrites in food is critically important for food safety. A Lactobacillus strain (Lactobacillus sp. DMDL 9010) was previously isolated from fermented vegetables by our group, and is not yet fully characterized. A number of phenotypical and genotypical approaches were employed to characterize Lactobacillus sp. DMDL 9010. Its nitrite degradation capacity was compared with four other Lactobacillus strains, including Lactobacillus casei subsp. rhamnosus 719, Lactobacillus delbrueckii subsp. bulgaricu 1.83, Streptococcus thermophilus 1.204, and lactobacillus plantarum 8140, on MRS medium. Compared to these four Lactobacillus strains, Lactobacillus sp. DMDL 9010 had a significantly higher nitrite degradation capacity (PLactobacillus sp. DMDL 9010 was identified as either Lactobacillus plantarum or Lactobacillus pentosus. To further identify this strain, the flanking regions (922 bp and 806 bp upstream and downstream, respectively) of the L-lactate dehydrogenase 1 (L-ldh1) gene were amplified and sequenced. Lactobacillus sp. DMDL 9010 had 98.92 and 76.98% sequence identity in the upstream region with L. plantarum WCFS1 and L. pentosus IG1, respectively, suggesting that Lactobacillu sp. DMDL 9010 is an L. plantarum strain. It was therefore named L. plantarum DMDL 9010. Our study provides a platform for genetic engineering of L. plantarum DMDL 9010, in order to further improve its nitrite degradation capacity. PMID:25423449

  6. Molecular characterization of Lactobacillus plantarum DMDL 9010, a strain with efficient nitrite degradation capacity.

    Directory of Open Access Journals (Sweden)

    Yong-tao Fei

    Full Text Available Nitrites commonly found in food, especially in fermented vegetables, are potential carcinogens. Therefore, limiting nitrites in food is critically important for food safety. A Lactobacillus strain (Lactobacillus sp. DMDL 9010 was previously isolated from fermented vegetables by our group, and is not yet fully characterized. A number of phenotypical and genotypical approaches were employed to characterize Lactobacillus sp. DMDL 9010. Its nitrite degradation capacity was compared with four other Lactobacillus strains, including Lactobacillus casei subsp. rhamnosus 719, Lactobacillus delbrueckii subsp. bulgaricu 1.83, Streptococcus thermophilus 1.204, and lactobacillus plantarum 8140, on MRS medium. Compared to these four Lactobacillus strains, Lactobacillus sp. DMDL 9010 had a significantly higher nitrite degradation capacity (P<0.001. Based on 16S rDNA sequencing and sequence comparison, Lactobacillus sp. DMDL 9010 was identified as either Lactobacillus plantarum or Lactobacillus pentosus. To further identify this strain, the flanking regions (922 bp and 806 bp upstream and downstream, respectively of the L-lactate dehydrogenase 1 (L-ldh1 gene were amplified and sequenced. Lactobacillus sp. DMDL 9010 had 98.92 and 76.98% sequence identity in the upstream region with L. plantarum WCFS1 and L. pentosus IG1, respectively, suggesting that Lactobacillu sp. DMDL 9010 is an L. plantarum strain. It was therefore named L. plantarum DMDL 9010. Our study provides a platform for genetic engineering of L. plantarum DMDL 9010, in order to further improve its nitrite degradation capacity.

  7. Molecular characterization of Lactobacillus plantarum DMDL 9010, a strain with efficient nitrite degradation capacity.

    Science.gov (United States)

    Fei, Yong-tao; Liu, Dong-mei; Luo, Tong-hui; Chen, Gu; Wu, Hui; Li, Li; Yu, Yi-gang

    2014-01-01

    Nitrites commonly found in food, especially in fermented vegetables, are potential carcinogens. Therefore, limiting nitrites in food is critically important for food safety. A Lactobacillus strain (Lactobacillus sp. DMDL 9010) was previously isolated from fermented vegetables by our group, and is not yet fully characterized. A number of phenotypical and genotypical approaches were employed to characterize Lactobacillus sp. DMDL 9010. Its nitrite degradation capacity was compared with four other Lactobacillus strains, including Lactobacillus casei subsp. rhamnosus 719, Lactobacillus delbrueckii subsp. bulgaricu 1.83, Streptococcus thermophilus 1.204, and lactobacillus plantarum 8140, on MRS medium. Compared to these four Lactobacillus strains, Lactobacillus sp. DMDL 9010 had a significantly higher nitrite degradation capacity (PDMDL 9010 was identified as either Lactobacillus plantarum or Lactobacillus pentosus. To further identify this strain, the flanking regions (922 bp and 806 bp upstream and downstream, respectively) of the L-lactate dehydrogenase 1 (L-ldh1) gene were amplified and sequenced. Lactobacillus sp. DMDL 9010 had 98.92 and 76.98% sequence identity in the upstream region with L. plantarum WCFS1 and L. pentosus IG1, respectively, suggesting that Lactobacillu sp. DMDL 9010 is an L. plantarum strain. It was therefore named L. plantarum DMDL 9010. Our study provides a platform for genetic engineering of L. plantarum DMDL 9010, in order to further improve its nitrite degradation capacity.

  8. The Medicinal Chemistry of Nitrite as a Source of Nitric Oxide Signaling.

    Science.gov (United States)

    Blood, Arlin B

    2017-01-01

    Conventional understanding of nitric oxide (NO) signaling in biology is commonly based on the premise that it simply diffuses randomly from its site of production by NO synthases to its site of action or inactivation. This notion has been challenged on a systemic cardiovascular scale with the realization that NO has endocrine effects despite being unable to exist in blood for more than a few milliseconds. Investigation of this phenomenon has led to the understanding that many of the chemical pathways that consume NO may not render it inactive as once thought. Instead, many of NO's metabolic products are still capable of carrying out NO signaling, or participate in NO-independent signaling in their own right. Nitrite and nitrate are two such products of NO metabolism that were once thought to be inert at physiological concentrations but are now known to contribute to NO bioactivity. The activity of nitrate is dependent upon its reduction to nitrite by bacterial nitrate reductase activity in the mouth. Nitrite can be reduced to NO by several metal-containing proteins under hypoxic conditions, or by nonenzymatic reactions under acidic conditions. Reduction and oxidation products of nitrite metabolism may also result in the production of NO adducts with a wide array of biological functions. The following review provides a general overview of the basic pathways underlying the physiological activity of nitrate and nitrite, as well as insight into the therapeutic potential of these pathways. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  9. TOWARDS FOOD SAFETY. POTENTIALLY HARMFUL ELEMENTS (PHEs FLUXES FROM SOIL TO FOOD CROPS

    Directory of Open Access Journals (Sweden)

    Claudio Bini

    2013-09-01

    Full Text Available Soil is the basis of the ecosystems and of our system of food production. Crops can uptake heavy metals and potentially toxic elements from the soil and store them in the roots or translocate them to the aerial parts. Excessive content of these elements in edible parts can produce toxic effects and, through the food chain and food consumption, result in a potential hazard for human health. In this study soils and plants (spring wheat, Triticum aestivum L. and maize, Zea mays L. from a tannery district in North-East Italy were analyzed to determine the content of some major and micro-nutrients and potentially toxic elements (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, P, Pb, S, Zn, V. The soils of the area are moderately polluted; Cr is the most important inorganic contaminant, followed by Ni, Cu and V. Factor analysis evidenced that the contaminants are in part anthropogenic and in part geogenic. Major anthropogenic origin was detected for Cr, Ni (from industrial activities, Zn, Cu, Cd (from agriculture practices. Biological Absorption Coefficient (BAC from soil to plant roots and Translocation factor (TF within the plant were calculated; major nutrients (K, P, S and some micronutrients (Cu, Zn, Mg, Mn are easily absorbed and translocated, whilst other nutrients (Ca, Fe and potentially toxic elements or micronutrients (Al, Cd, Cr, Ni, Pb, V are not accumulated in the seeds of the two considered plants. However, the two edible species proved differently able to absorb and translocate elements, and this suggests to consider separately every species as potential PHEs transporter to the food chain and to humans. Cr concentrations in seeds and other aerial parts (stem and leaves of the examined plants are higher than the values found for the same species and for other cereals grown on unpolluted soils. Comparing the Cr levels in edible parts with recommended dietary intake, besides other possible Cr sources (dust ingestion, water, there seems to be no

  10. Potentials and challenges associated with automated closed dynamic chamber measurements of soil CO2 fluxes

    Science.gov (United States)

    Görres, Carolyn-Monika; Kammann, Claudia; Ceulemans, Reinhart

    2015-04-01

    Soil respiration fluxes are influenced by natural factors such as climate and soil type, but also by anthropogenic activities in managed ecosystems. As a result, soil CO2 fluxes show a large intra- and interannual as well as intra- and intersite variability. Most of the available soil CO2 flux data giving insights into this variability have been measured with manually closed static chambers, but technological advances in the past 15 years have also led to an increased use of automated closed chamber systems. The great advantage of automated chambers in comparison to manually operated chambers is the higher temporal resolution of the flux data. This is especially important if we want to better understand the effects of short-term events, e.g. fertilization or heavy rainfall, on soil CO2 flux variability. However, the chamber method is an invasive measurement method which can potentially alter soil CO2 fluxes and lead to biased measurement results. In the peer-reviewed literature, many papers compare the field performance and results of different closed static chamber designs, or compare manual chambers with automated chamber systems, to identify potential biases in CO2 flux measurements, and thus help to reduce uncertainties in the flux data. However, inter-comparisons of different automated closed dynamic chamber systems are still lacking. Here we are going to present a field comparison of the most-cited automated chamber system, the LI-8100A Automated Soil Flux System, with the also commercially available Greenhouse Gas Monitoring System AGPS. Both measurement systems were installed side by side at a recently harvested poplar bioenergy plantation (POPFULL, http://uahost.uantwerpen.be/popfull/) from April 2014 until August 2014. The plantation provided optimal comparison conditions with a bare field situation after the harvest and a regrowing canopy resulting in a broad variety of microclimates. Furthermore, the plantation was planted in a double-row system with

  11. Soil Oxidation-Reduction Potential and Plant Photosynthetic Capacity in the Northern Pantanal of Mato Grosso, Brazil

    Science.gov (United States)

    Lathuilliere, M. J.; Johnson, M. S.; Dalmagro, H. J.; Pinto Junior, O. B.; Couto, E. G.

    2013-12-01

    Plant communities of the Pantanal wetland are able to survive long periods of climatic and physiological stress in the dry and wet seasons. During inundation, soil oxygen demand increases dramatically as reducing soil conditions create stress in the root system with possible impacts on photosynthetic capacity of plants. We look at inundation cycles of a tree island (locally known as a cordilheira) in the Northern Pantanal near Poconé, Mato Grosso, and relate soil oxidation-reduction potential and soil oxygen depletion to the photosynthetic capacity of two plant communities of flooded scrub forest (Vochysia divergens and Curatela americana). Results show a drop in soil oxidation-reduction potential of over 400 mV, to levels below the absolute value of -200 mV, following inundation around the tree island. Both plant species showed increased carbon assimilation at highest soil oxygen demand despite a change in stomatal conductance, suggesting adaptation to the inundated environment. Absolute values of soil oxidation-reduction potential also allow for the determination of specific soil chemical reactions characteristic of the tree island environment, namely the reduction of iron(III), or carbon dioxide which in turn produces methane. Our combined analysis of soil chemistry with plant ecophysiology allows for a better understanding of soil-plant interactions in the Pantanal, specifically the drivers of biogeochemical processes between inundation periods.

  12. An Experimental Study of Effects in Soils by Potential CO2 Seepage

    Science.gov (United States)

    Wei, Y.; Caramanna, G.; Nathanail, P.; Steven, M.; Maroto-Valer, M.

    2011-12-01

    Potential CO2 seepage during a CCS project will not only reduce its performing efficiency, but can also impact the local environment. Though scientists announce with confidence that CCS is a safe technology to store CO2 deep underground, it is essential to study the effects of CO2 seepage, to avoid any possible influences on soils. As a simplified environment, laboratory experiments can easily be controlled and vital to be studied to be compared with more complex natural analogues and modelling works. Recent research focuses on the effects on ecosystems of CO2 leakage. However, the impacts of long-term, low level exposure for both surface and subsurface ecosystems, as well as soil geochemistry changes are currently not clear. Moreover, previous work has focussed on pure CO2 leakage only and its impacts on the ecosystem. However, in a more realistic scenario the gas coming from a capture process may contain impurities, such as SO2, which are more dangerous than pure CO2 and could cause more severe consequences. Therefore, it is critical to assess the potential additional risks caused by CO2 leakage with impurities. Accordingly, both a batch and a continuous flow reactor were designed and used to study potential impacts caused by the CO2 seepage, focusing on soil geochemistry changes, due to different concentrations of CO2/SO2 mixtures. Stage 1- Batch experiments. In this stage, a soil sample was collected from the field and exposed to a controlled CO2/SO2 gas mixtures (100% CO2 and CO2:SO2=99:1). The water soluble fractions were measured before and after incubation. With 100% CO2 incubation it was found that: 1) the pH in the soil sample did not change significantly; 2) for soils with different moisture levels, greater moisture in the soil results in higher CO2 uptake during incubation; and 3) for sandy soils, small changes in CaCl2-exchangeable metal concentration, were observed after CO2 incubation. However, the increased concentration of toxic elements is still

  13. Processing protocol for soil samples potentially contaminated with Bacillus anthracis spores [HS7.52.02 - 514

    Science.gov (United States)

    Silvestri, Erin E.; Griffin, Dale W.

    2017-01-01

    This protocol describes the processing steps for 45 g and 9 g soil samples potentially contaminated with Bacillus anthracis spores. The protocol is designed to separate and concentrate the spores from bulk soil down to a pellet that can be used for further analysis. Soil extraction solution and mechanical shaking are used to disrupt soil particle aggregates and to aid in the separation of spores from soil particles. Soil samples are washed twice with soil extraction solution to maximize recovery. Differential centrifugation is used to separate spores from the majority of the soil material. The 45 g protocol has been demonstrated by two laboratories using both loamy and sandy soil types. There were no significant differences overall between the two laboratories for either soil type, suggesting that the processing protocol would be robust enough to use at multiple laboratories while achieving comparable recoveries. The 45 g protocol has demonstrated a matrix limit of detection at 14 spores/gram of soil for loamy and sandy soils.

  14. Potential Nitrification and Nitrogen Mineral of Soil in Coffee Agroforestry System with Various Shading Trees

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    Purwanto .

    2007-05-01

    Full Text Available The role of shading trees in coffee farms has been well understood to establish suitable condition for the growth of coffee trees, on the other hand their role in nitrogen cycle in coffee farming is not yet well understood. The objectives of this study are to investigate the influence of various legume shading trees on the concentration of soil mineral N (N-NH4 + and N-NO3-, potential nitrification and to study the controlling factors of nitrification under field conditions. This field explorative research was carried out in Sumberjaya, West Lampung. Twelve observation plots covered four land use systems (LUS, i.e. 1 Coffee agroforestry with Gliricidiasepium as shade trees; 2 Coffee agroforestry with Gliricidiaas shade trees and Arachis pintoias cover crops; 3Coffee agroforestry with Paraserianthes falcataria as shade trees; and 4 Mixed/multistrata coffee agroforestry with Gliricidiaand other fruit crops as shade trees. Measurements of soil mineral-N concentration were carried out every three weeks for three months. Results showed that shade tree species in coffee agroforestry significantly affected concentrations of soil NH4 +, NO3- and potential nitrification. Mixed coffee agroforestry had the highest NH4+/N-mineral ratio (7.16% and the lowest potential nitrification (0.13 mg NO2-kg-1 hour -1 compared to other coffee agroforestry systems using single species of leguminous shade trees. Ratio of NH4 + /N-mineral increased 0.8—21% while potential nitrification decreased 55—79% in mixed coffee agroforestry compared to coffee agroforestry with Gliricidia or P. falcatariaas shade trees. Coffee agroforestry with P. falcatariaas shade trees had potential nitrification 53% lower and ratio of NH4 + /N-mineral concentration 20% higher than that with Gliricidia. Coffee agroforestry with P. falcataria as shade trees also had organic C content 17% higher, total N 40% higher, available P 112% higher than that with Gliricidia. The presence of A. pintoiin

  15. Standard test method for measurement of oxidation-reduction potential (ORP) of soil

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This test method covers a procedure and related test equipment for measuring oxidation-reduction potential (ORP) of soil samples removed from the ground. 1.2 The procedure in Section 9 is appropriate for field and laboratory measurements. 1.3 Accurate measurement of oxidation-reduction potential aids in the analysis of soil corrosivity and its impact on buried metallic structure corrosion rates. 1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  16. Isolation and characterization of soil Streptomyces species as potential biological control agents against fungal plant pathogens.

    Science.gov (United States)

    Evangelista-Martínez, Zahaed

    2014-05-01

    The use of antagonist microorganisms against fungal plant pathogens is an attractive and ecologically alternative to the use of chemical pesticides. Streptomyces are beneficial soil bacteria and potential candidates for biocontrol agents. This study reports the isolation, characterization and antagonist activity of soil streptomycetes from the Los Petenes Biosphere Reserve, a Natural protected area in Campeche, Mexico. The results showed morphological, physiological and biochemical characterization of six actinomycetes and their inhibitory activity against Curvularia sp., Aspergillus niger, Helminthosporium sp. and Fusarium sp. One isolate, identified as Streptomyces sp. CACIS-1.16CA showed the potential to inhibit additional pathogens as Alternaria sp., Phytophthora capsici, Colletotrichum sp. and Rhizoctonia sp. with percentages ranging from 47 to 90 %. This study identified a streptomycete strain with a broad antagonist activity that could be used for biocontrol of plant pathogenic fungi.

  17. Mutagenesis breeding research of Lactobacillus brevis of nitrite reduction

    Directory of Open Access Journals (Sweden)

    LI Zeli

    2015-10-01

    Full Text Available The pollution of nitrite in food became one of the focus of food safety issues,the use of biotechnology methods degrading nitrite became hotspot.The primitive strain was Lactobacillus brevis C2,preserved in our laboratory,had the ability to degrade nitrite,through composite mutagenesis of 15 W,254 nm,20 cm ultraviolet mutagenesis (UV for 120 s and 0.8% diethyl sulfate(DES in 37℃ mutation for 40 min,after screening,we successfully obtained high efficient strain of nitrite degradation,named UV6-DS2,relative to the starting strain,under the condition of 400 mg/L nitrite,after 12 h degradation,nitrite degradation rate increased from 92.8% to 97.8%,to explore its application in food was able to effectively reduce concentration of nitrite in food.

  18. Potential effects of earthworm activity on C and N dynamics in tropical paddy soil

    Science.gov (United States)

    John, Katharina; Zaitsev, Andrey S.; Wolters, Volkmar

    2016-04-01

    activity. The mean relative C loss with leaching was increased by earthworms under intensive fertilization and consequently resulting soil C content in the end of Experiment 2 decreased. N concentration in the leachate remained unaffected by earthworms although the remaining N content in soil with straw application and earthworm treatment was significantly higher than in the control. Our results showed that the potential role of earthworms in C-stabilization is confined to moderately irrigated soils that allow high earthworm activity. Earthworm effects on C and N release under non-flooded conditions were largely modulated by the application of N fertilizer (urea) and by the amendment of rice straw. Our findings suggest that the presence of earthworms significantly affect C and N budgets in rice paddy soil, especially in the intensively managed non-flooded fields. In the short term perspective they sequester C and N loss from soil. However, in the longer term (ca. 30 days) this sequestration effect remains significant only for nitrogen under the straw application treatment. The study was supported by ICON project within the DFG-Research Unit FOR 1701.

  19. Agglomeration Determines Effects of Carbonaceous Nanomaterials on Soybean Nodulation, Dinitrogen Fixation Potential, and Growth in Soil.

    Science.gov (United States)

    Wang, Ying; Chang, Chong Hyun; Ji, Zhaoxia; Bouchard, Dermont C; Nisbet, Roger M; Schimel, Joshua P; Gardea-Torresdey, Jorge L; Holden, Patricia A

    2017-06-27

    The potential effects of carbonaceous nanomaterials (CNMs) on agricultural plants are of concern. However, little research has been performed using plants cultivated to maturity in soils contaminated with various CNMs at different concentrations. Here, we grew soybean for 39 days to seed production in soil amended with 0.1, 100, or 1000 mg kg-1 of either multiwalled carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs), or carbon black (CB) and studied plant growth, nodulation, and dinitrogen (N2) fixation potential. Plants in all CNM treatments flowered earlier (producing 60% to 372% more flowers when reproduction started) than the unamended controls. The low MWCNT-treated plants were shorter (by 15%) with slower leaf cover expansion (by 26%) and less final leaf area (by 24%) than the controls. Nodulation and N2 fixation potential appeared negatively impacted by CNMs, with stronger effects at lower CNM concentrations. All CNM treatments reduced the whole-plant N2 fixation potential, with the highest reductions (by over 91%) in the low and medium CB and the low MWCNT treatments. CB and GNPs appeared to accumulate inside nodules as observed by transmission electron microscopy. CNM dispersal in aqueous soil extracts was studied to explain the inverse dose-response relationships, showing that CNMs at higher concentrations were more agglomerated (over 90% CNMs settled as agglomerates >3 μm after 12 h) and therefore proportionally less bioavailable. Overall, our findings suggest that lower concentrations of CNMs in soils could be more impactful to leguminous N2 fixation, owing to greater CNM dispersal and therefore increased bioavailability at lower concentrations.

  20. Inhibition kinetics of nitritation and half-nitritation of old landfill leachate in a membrane bioreactor.

    Science.gov (United States)

    Li, Yun; Wang, Zhaozhao; Li, Jun; Wei, Jia; Zhang, Yanzhuo; Zhao, Baihang

    2017-04-01

    Nitritation can be used as a pretreatment for anaerobic ammonia oxidation (anammox). Various control strategies for nitritation and half-nitritation of old landfill leachate in a membrane bioreactor were investigated in this study and the inhibition kinetics of substrate, product and old landfill leachate on nitritation were analyzed via batch tests. The results demonstrated that old landfill leachate nitritation in the membrane bioreactor can be achieved by adjusting the influent loading and dissolved oxygen (DO). From days 105-126 of the observation period, the average effluent concentration was 871.3 mg/L and the accumulation rate of [Formula: see text] was 97.2%. Half-nitritation was realized quickly by adjusting hydraulic retention time and DO. A low-DO control strategy appeared to best facilitate long-term and stable operation. Nitritation inhibition kinetic experiments showed that the inhibition of old landfill leachate was stronger than that of the substrate [Formula: see text] or product [Formula: see text] . The ammonia oxidation rate dropped by 22.2% when the concentration of old landfill leachate (calculated in chemical oxygen demand) was 1600.2 mg/L; further, when only free ammonia or free nitrous acid were used as a single inhibition factor, the ammonia oxidation rate dropped by 4.7-6.5% or 14.5-15.9%, respectively. Haldane, Aiba, and a revised inhibition kinetic model were adopted to separately fit the experimental data. The R 2 correlation coefficient values for these three models were 0.982, 0.996, and 0.992, respectively. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  1. Adaptability as the key to success for the ubiquitous marine nitrite oxidizer Nitrococcus.

    Science.gov (United States)

    Füssel, Jessika; Lücker, Sebastian; Yilmaz, Pelin; Nowka, Boris; van Kessel, Maartje A H J; Bourceau, Patric; Hach, Philipp F; Littmann, Sten; Berg, Jasmine; Spieck, Eva; Daims, Holger; Kuypers, Marcel M M; Lam, Phyllis

    2017-11-01

    Nitrite-oxidizing bacteria (NOB) have conventionally been regarded as a highly specialized functional group responsible for the production of nitrate in the environment. However, recent culture-based studies suggest that they have the capacity to lead alternative lifestyles, but direct environmental evidence for the contribution of marine nitrite oxidizers to other processes has been lacking to date. We report on the alternative biogeochemical functions, worldwide distribution, and sometimes high abundance of the marine NOB Nitrococcus. These largely overlooked bacteria are capable of not only oxidizing nitrite but also reducing nitrate and producing nitrous oxide, an ozone-depleting agent and greenhouse gas. Furthermore, Nitrococcus can aerobically oxidize sulfide, thereby also engaging in the sulfur cycle. In the currently fast-changing global oceans, these findings highlight the potential functional switches these ubiquitous bacteria can perform in various biogeochemical cycles, each with distinct or even contrasting consequences.

  2. Conceptional Considerations to Energy Balance and Global Warming Potential of Soil Bioengineering Structures

    Science.gov (United States)

    von der Thannen, Magdalena; Paratscha, Roman; Smutny, Roman; Lampalzer, Thomas; Strauss, Alfred; Rauch, Hans Peter

    2016-04-01

    Nowadays there is a high demand on engineering solutions considering not only technical aspects but also ecological and aesthetic values. In this context soil bioengineering techniques are often used as standalone solutions or in combination with conventional engineering structures. It is a construction technique that uses biological components for hydraulic and civil engineering solutions. In general it pursues the same objectives as conventional civil engineering structures. Currently the used assessment methods for soil bioengineering structures are referencing technically, ecologically and socio-economically. In a modern engineering approach additionally, environmental impacts and potential added values should be considered. The research project E-Protect aims at developing Environmental Life Cycle Assessment (LCA) models for this special field of alpine protective constructions. Both, the Cumulative Energy Demand (CED) and the Global Warming Potential (GWP) should be considered in an Environmental LCA over the whole life cycle of an engineering structure. The life cycle itself can be divided into three phases: the construction phase, the use phase and the end of life phase. The paper represents a concept to apply an Environmental LCA model for soil bioengineering structures. Beside the construction phase of these structures particular attention will be given to the use phase. It is not only important in terms of engineering effects but also plays an important role for positive carbon footprint due to the growing plants of soil bioengineering structures in contrast to conventional structures. Innovative Environmental LCA models will be applied to soil bioengineering structures which provide a new transparency for the responsible planners and stakeholders, by pointing out the total consumption of resources in all construction phases and components.

  3. Hydrogen Isotopes in Amino Acids and Soils Offer New Potential to Study Complex Processes

    Science.gov (United States)

    Fogel, M. L.; Newsome, S. D.; Williams, E. K.; Bradley, C. J.; Griffin, P.; Nakamoto, B. J.

    2016-12-01

    Hydrogen isotopes have been analyzed extensively in the earth and biogeosciences to trace water through various environmental systems. The majority of the measurements have been made on water in rocks and minerals (inorganic) or non-exchangeable H in lipids (organic), important biomarkers that represent a small fraction of the organic molecules synthesized by living organisms. Our lab has been investigating hydrogen isotopes in amino acids and complex soil organic matter, which have traditionally been thought to be too complex to interpret owing to complications from potentially exchangeable hydrogen. For the amino acids, we show how hydrogen in amino acids originates from two sources, food and water, and demonstrate that hydrogen isotopes can be routed directly between organisms. Amino acid hydrogen isotopes may unravel cycling in extremophiles in order to discover novel biochemical pathways central to the organism. For soil organic matter, recent approaches to understanding the origin of soil organic matter are pointing towards root exudates along with microbial biomass as the source, rather than aboveground leaf litter. Having an isotope tracer in very complex, potentially exchangeable organic matter can be handled with careful experimentation. Although no new instrumentation is being used per se, extension of classes of organic matter to isotope measurements has potential to open up new doors for understanding organic matter cycling on earth and in planetary materials.

  4. Scientific case studies in land-use driven soil erosion in the central United States: Why soil potential and risk concepts should be included in the principles of soil health

    Directory of Open Access Journals (Sweden)

    Benjamin L. Turner

    2018-03-01

    Full Text Available Despite recent improvements in overall soil health gained through conservation agriculture, which has become a global priority in agricultural systems, soil and water-related externalities (e.g., wind and water erosion continue to persist or worsen. Using an inductive, systems approach, we tested the hypothesis that such externalities persist due to expansion of cultivation onto areas unsuitable for sustained production. To test this hypothesis, a variety of data sources and analyses were used to uncover the land and water resource dynamics underlying noteworthy cases of soil erosion (either wind or water and hydrological effects (e.g., flooding, shifting hydrographs throughout the central United States. Given the evidence, we failed to reject the hypothesis that cultivation expansion is contributing to increased soil and water externalities, since significant increases in cultivation on soils with severe erosion limitations were observed everywhere the externalities were documented. We discuss the case study results in terms of land use incentives (e.g., policy, economic, and biophysical, developing concepts of soil security, and ways to utilize case studies such as those presented to better communicate the value of soil and water resource conservation. Incorporating the tenets of soil potential and soil risk into soil health evaluations and cultivation decision-making is needed to better match the soil resource with land use and help avoid more extreme soil and water-related externalities.

  5. Endosulfan Resistance Profile of Soil Bacteria and Potential Application of Resistant Strains in Bioremediation

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    Chandini P.K.

    2014-05-01

    Full Text Available In the present study, bacterial strains were isolated from the soils of Wayanad District, Kerala, India and the isolates were tested for their tolerance to endosulfan and potential in bioremediation technology. Pesticide contamination in the soils, soil physico-chemical characteristics and socio-economic impacts of pesticide application were also analyzed. 28 pesticide compounds in the soil samples were analyzed and the results revealed that there was no pesticide residues in the soils. As per the survey conducted the pesticide application is very high in the study area and the level of awareness among the farmers was very poor regarding the method of application and its socio-economic and ecological impacts. A total of 9 bacterial strains were isolated with 50μg/ml of endosulfan in the isolating media and the results showed that most of the bacterial strains were highly resistance to endosulfan. Out of the 9 strains isolated 6 were highly resistant to endosulfan (500- 700μg/ml and the other 3 isolates showed the resistance of 250-500μg/ml. From the studied isolate, isolate 9 demonstrating prolific growth and high resistance was selected to check their capability to degrade endosulfan over time. Identification of the selected strain reveals that it belongs to the genus Bacillus. Results of endosulfan removal studies showed that with increase in time, the biomass of the bacterial strains increased. The complete disappearance of endosulfan from the spiked and inoculated broth during the first day of incubation (24 hour interval was observed. While the control flask showed the presence of endosulfan during the experimental period. Pesticide resistant bacteria are widely distributed in the soils of selected study area and the tolerance varied between bacteria even though they were isolated from the soils of the same area. The selected Bacillus species carry the ability to degrade endosulfan at accelerated rates and it could be useful in framing a

  6. Arsenic, chromium, molybdenum, and selenium: Geochemical fractions and potential mobilization in riverine soil profiles originating from Germany and Egypt.

    Science.gov (United States)

    Shaheen, Sabry M; Kwon, Eilhann E; Biswas, Jayanta K; Tack, Filip M G; Ok, Yong Sik; Rinklebe, Jörg

    2017-08-01

    The fractionation and potential mobilization of As, Cr, Mo, and Se in four floodplain soil profiles collected along the Nile (Egypt) and Wupper (Germany) Rivers were assessed using the BCR sequential extraction procedure. The concentrations of total and the geochemical fractions (acid soluble (F1), reducible (F2), oxidizable (F3), and residual (F4) fraction) of the elements were determined. The Wupper soils had the highest total concentrations (mg kg -1 ) of As (378) and Cr (2,797) while the Nile soils contained the highest total Mo (12) and Se (42). The residual fraction of As, Cr, Mo, and Se was dominant in the Nile soils suggesting the geogenic source of the elements in these soils. The residual fraction of As and Mo and the oxidizable fraction of Cr and Se were dominant in the Wupper soils. Among the non-residual fractions (potential mobile fractions; PMF = ∑F1-F3), the oxidizable fraction was dominant for Cr, Mo, and Se in the Nile soils and for Mo in the Wupper soils, while the reducible fraction was dominant for As in both soils. The PMF of As, Cr, and Se was higher in the Wupper than in the Nile soils which might reflect the anthropogenic sources of these elements in the Wupper soils, while the opposite was the case for the PMF of Mo. The high PMF of Se (87%), Cr (87%), and As (21%) in the Wupper soils suggested that a release of these toxic elements may happen which increase the potential environmental risks in the anthropogenically polluted soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Mapping soil erosion hotspots and assessing the potential impacts of land management practices in the highlands of Ethiopia

    Science.gov (United States)

    Tamene, Lulseged; Adimassu, Zenebe; Ellison, James; Yaekob, Tesfaye; Woldearegay, Kifle; Mekonnen, Kindu; Thorne, Peter; Le, Quang Bao

    2017-09-01

    An enormous effort is underway in Ethiopia to address soil erosion and restore overall land productivity. Modelling and participatory approaches can be used to delineate erosion hotspots, plan site- and context-specific interventions and assess their impacts. In this study, we employed a modelling interface developed based on the Revised Universal Soil Loss Equation adjusted by the sediment delivery ratio to map the spatial distribution of net soil loss and identify priority areas of intervention. Using the modelling interface, we also simulated the potential impacts of different soil and water conservation measures in reducing net soil loss. Model predictions showed that net soil loss in the study area ranges between 0.4 and 88 t ha- 1 yr- 1 with an average of 12 t ha- 1 yr- 1. The dominant soil erosion hotspots were associated with steep slopes, gullies, communal grazing and cultivated areas. The average soil loss observed in this study is higher than the tolerable soil loss rate estimated for the highland of Ethiopia. The scenario analysis results showed that targeting hotspot areas where soil loss exceeds 10 t ha- 1 yr- 1 could reduce net soil loss to the tolerable limit (< 2 t ha- 1 yr- 1). The spatial distribution of soil loss and the sediment yield reduction potential of different options provided essential information to guide prioritization and targeting. In addition, the results can help promoting awareness within the local community of the severity of the soil erosion problem and the potential of management interventions. Future work should include cost-benefit and tradeoff analyses of the various management options for achieving a given level of erosion reduction.

  8. Chemical Speciation and Potential Mobility of Heavy Metals in the Soil of Former Tin Mining Catchment

    Directory of Open Access Journals (Sweden)

    M. A. Ashraf

    2012-01-01

    Full Text Available This study describes the chemical speciation of Pb, Zn, Cu, Cr, As, and Sn in soil of former tin mining catchment. Total five sites were selected for sampling and subsequent subsamples were collected from each site in order to create a composite sample for analysis. Samples were analysed by the sequential extraction procedure using optical emission spectrometry (ICP OES. Small amounts of Cu, Cr, and As retrieved from the exchangeable phase, the ready available for biogeochemical cycles in the ecosystem. Low quantities of Cu and As could be taken up by plants in these kind of acidic soils. Zn not detected in the bioavailable forms while Pb is only present in negligible amounts in very few samples. The absence of mobile forms of Pb eliminates the toxic risk both in the trophic chain and its migration downwards the soil profile. The results also indicate that most of the metals have high abundance in residual fraction indicating lithogenic origin and low bioavailability of the metals in the studied soil. The average potential mobility for the metals giving the following order: Sn > Cu > Zn > Pb > Cr > As.

  9. Potentially toxic elements (PTEs) in soils from the surroundings of the Trans-Amazonian Highway, Brazil.

    Science.gov (United States)

    de Souza, Edna Santos; Fernandes, Antonio Rodrigues; de Souza Braz, Anderson Martins; Sabino, Lorena Lira Leite; Alleoni, Luís Reynaldo Ferracciú

    2015-01-01

    The Trans-Amazonian Highway (TAH) is located in the northern region of Brazil, comprising a border region where agricultural, mining, and logging activities are the main activities responsible for fostering economic development, in addition to large hydroelectric plants. Such activities lead to environmental contamination by potentially toxic elements (PTEs). Environmental monitoring is only possible through the determination of element contents under natural conditions. Many extraction methods have been proposed to determine PTEs' bioavailability in the soil; however, there is no consensus about which extractor is most suitable. In this study, we determined the contents of PTEs in soils in the surroundings of TAH after mineral extraction with diethylenetriaminepentaacetic acid-triethanolamine (DTPA-TEA), Mehlich I, and Mehlich III solutions. Soil samples were collected in areas of natural vegetation in the vicinity of TAH in the state of Pará, Brazil. Chemical attributes and particle size were determined, besides concentrations of Fe, Al, Mn, and Ti by sulfuric acid digestion, Si after alkaline solution attack, and poorly crystalline Fe, Al, and "free" Fe oxides. Mehlich III solution extracted greater contents from Fe, Al, and Pb as compared to Mehlich I and DTPA-TEA and similar contents from Cd, Mn, Zn, and Cu. Significant correlations were found between concentrations of PTEs and the contents of Fe and Mn oxides as well as organic carbon and soil cation exchange capacity. Contents of Cu, Mn, Fe, and Zn by the three methods were positively correlated.

  10. Polar metabolites of polycyclic aromatic compounds from fungi are potential soil and groundwater contaminants.

    Science.gov (United States)

    Boll, Esther S; Johnsen, Anders R; Christensen, Jan H

    2015-01-01

    This study investigated the sorption to soil of water-soluble metabolites from polycyclic aromatic compounds (PACs). The soil fungus Cunninghamella elegans was used to produce PAC metabolites from two un-substituted PACs (phenanthrene, pyrene), three alkyl-substituted PACs (2-methylnaphthalene, 1-methylphenanthrene, 1-methylpyrene), and one sulfur-containing heterocyclic PAC (dibenzothiophene). Fifty-eight metabolites were tentatively identified; metabolites from the un-substituted PACs were hydroxylated and sulfate conjugated, whereas metabolites from alkyl-substituted PACs were sulfate conjugated and either hydroxylated or oxidized to carboxylic acids at the methyl group. The metabolism of the sulfur-containing heterocyclic PAC resulted in sulfate conjugates. The sorption of the PAC metabolites to three soils was determined using a batch equilibrium method, and partition coefficients (Kd's) were calculated for fourteen representative metabolites. Sulfate conjugated metabolites displayed Kd's below 70 whereas the metabolites with both a sulfate and a carboxylic acid group had Kd's below 2.8. The low Kd's of water-soluble PAC metabolites indicate high mobility in soil and a potential for leaching to surface- and groundwaters. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. CONTAMINATION POTENTIAL OF SPECIFIC IONS IN SOIL TREATED WITH REJECT BRINE FROM DESALINATION PLANTS

    Directory of Open Access Journals (Sweden)

    ANDLER MILTON PAIVA DE OLIVEIRA

    2016-01-01

    Full Text Available Percolation columns constructed in the Laboratory can predict the degree of contamination in soil due to reject brine disposal and can be a tool for reducing environmental impacts. This study aim to evaluate the mobilization of ions in reject brine from desalination process by reverse osmosis. The mobilization of the contaminant ions in the saline waste was studied in glass percolation columns, which were filled with soil of contrasting textures (eutrophic CAMBISOL, typic dystrophic Red OXISOL, ENTISOL Quartzipsamment. Experiments ware repeated three times each, and the initial and final concentrations of the ion contaminants were analyzed. The pollution potential of this wastewater was determined by the retardation factor and dispersion-diffusion coefficient of K+, Cl- and Na+ for each studied soil. The differences in the displacement curves of the ions present in the saline waste among various soil types were analyzed. The Entisol Quartzipsamment showed a higher forward speed of the ions K+ and Cl- (greater retardation factor, i.e., greater power of the subsurface contamination for these ions. In typic dystrophic Red OXISOL, the ions move with greater ease and therefore produced greater groundwater contamination. In eutrophic CAMBISOL, the low coefficient of diffusion-dispersion in all ions was evaluated (i.e., reduced ion mobility is directly influenced by their exchangeable levels.

  12. Evaluation of soil characteristics potentially affecting arsenic concentration in paddy rice (Oryza sativa L.)

    Energy Technology Data Exchange (ETDEWEB)

    Bogdan, Katja, E-mail: katja.bogdan@pflern.uni-hannover.d [Institute of Plant Nutrition, Leibniz Universitaet Hannover, Herrenhaeuser Str. 2, 30419 Hannover (Germany); Schenk, Manfred K., E-mail: schenk@pflern.uni-hannover.d [Institute of Plant Nutrition, Leibniz Universitaet Hannover, Herrenhaeuser Str. 2, 30419 Hannover (Germany)

    2009-10-15

    Paddy rice may contribute considerably to the human intake of As. The knowledge of soil characteristics affecting the As content of the rice plant enables the development of agricultural measures for controlling As uptake. During field surveys in 2004 and 2006, plant samples from 68 fields (Italy, Po-area) revealed markedly differing As concentration in polished rice. The soil factors total As{sub (aquaregia)}, pH, grain size fractions, total C, plant available P{sub (CAL)}, poorly crystalline Fe{sub (oxal.)} and plant available Si{sub (Na-acetate)} content that potentially affect As content of rice were determined. A multiple linear regression analysis showed a significant positive influence of the total As{sub (aquaregia)} and plant available P{sub (CAL)} content and a negative influence of the poorly crystalline Fe{sub (oxal.)} content of the soil on the As content in polished rice and rice straw. Si concentration in rice straw varied widely and was negatively related to As content in straw and polished rice. - Field selection for total As, poorly crystalline Fe and plant available P in soil might contribute to control As content of paddy rice.

  13. Soil radon measurements as a potential tracer of tectonic and volcanic activity.

    Science.gov (United States)

    Neri, Marco; Ferrera, Elisabetta; Giammanco, Salvatore; Currenti, Gilda; Cirrincione, Rosolino; Patanè, Giuseppe; Zanon, Vittorio

    2016-04-15

    In Earth Sciences there is a growing interest in studies concerning soil-radon activity, due to its potential as a tracer of numerous natural phenomena. Our work marks an advance in the comprehension of the interplay between tectonic activity, volcanic eruptions and gas release through faults. Soil-radon measurements, acquired on Mt. Etna volcano in 2009-2011, were analyzed. Our radon probe is sensitive to changes in both volcanic and seismic activity. Radon data were reviewed in light of the meteorological parameters. Soil samples were analyzed to characterize their uranium content. All data have been summarized in a physical model which identifies the radon sources, highlights the mechanism of radon transport and envisages how such a mechanism may change as a consequence of seismicity and volcanic events. In the NE of Etna, radon is released mainly from a depth of 50 m/day. Three periods of anomalous gas release were found (February 2010, January and February 2011). The trigger of the first anomaly was tectonic, while the second and third had a volcanic origin. These results mark a significant step towards a better understanding of the endogenous mechanisms that cause changes in soil-radon emission at active volcanoes.

  14. PAHs contamination in urban soils from Lisbon: spatial variability and potential risks

    Science.gov (United States)

    Cachada, Anabela; Pereira, Ruth; Ferreira da Silva, Eduardo; Duarte, Armando

    2015-04-01

    Polycyclic Aromatic hydrocarbons (PAHs) can become major contaminants in urban and industrial areas, due to the existence of a plethora of diffuse and point sources. Particularly diffuse pollution, which is normally characterized by continuous and long-term emission of contaminants below risk levels, can be a major problem in urban areas. Since PAHs are persistent and tend to accumulate in soils, levels are often above the recommended guidelines indicating that ecological functions of soils may be affected. Moreover, due to the lipophilic nature, hydrophobicity and low chemical and biological degradation rates of PAHs, which leads to their bioconcentration and bioamplification, they may reach toxicological relevant concentrations in organisms. The importance and interest of studying this group of contaminants is magnified due to their carcinogenic, mutagenic and endocrine disrupting effects. In this study, a risk assessment framework has been followed in order to evaluate the potential hazards posed by the presence of PAHs in Lisbon urban soils. Hence, the first step consisted in screening the total concentrations of PAHs followed by the calculation of risks based on existing models. Considering these models several samples were identified as representing a potential risk when comparing with the guidelines for soil protection. Moreover, it was found that for 38% of samples more than 50% of species can be potentially affected by the mixture of PAHs. The use of geostatistical methods allowed to visualize the predicted distribution of PAHs in Lisbon area and identify the areas where possible risk to the environment are likely occurring However, it is known that total concentration may not allow a direct prediction of environmental risk, since in general only a fraction of total concentration is available for partitioning between soil and solution and thus to be uptake or transformed by organisms (bioacessible or bioavailable) or to be leached to groundwater. The

  15. Assessing effects of native forest restoration on soil moisture dynamics and potential aquifer recharge, Auwahi, Maui

    Science.gov (United States)

    Perkins, Kim S.; Nimmo, John R.; Medeiros, Arthur C.; Szutu, Daphne J.; von Allmen, Erica

    2014-01-01

    Understanding the role of soils in regulating water flow through the unsaturated zone is critical in assessing the influence of vegetation on soil moisture dynamics and aquifer recharge. Because of fire, introduced ungulates and landscape-level invasion of non-native grasses, less than 10% of original dry forest (~730 mm precipitation annually) still exists on leeward Haleakalā, Maui, Hawaiian Islands. Native dry forest restoration at Auwahi has demonstrated the potential for dramatic revegetation, allowing a unique experimental comparison of hydrologic function between tracts of restored forest and adjacent grasslands. We hypothesized that even relatively recent forest restoration can assist in the recovery of impaired hydrologic function, potentially increasing aquifer recharge. To compare restored forest and grassland sites, we experimentally irrigated and measured soil moisture and temperature with subsurface instrumentation at four locations within the reforested area and four within the grassland, each with a 2·5 × 2·5-m plot. Compared with grassland areas, water in reforested sites moved to depth faster with larger magnitude changes in water content. The median first arrival velocity of water was greater by a factor of about 13 in the reforested sites compared with the grassland sites. This rapid transport of water to depths of 1 m or greater suggests increased potential aquifer recharge. Improved characterization of how vegetation and soils influence recharge is crucial for understanding the long-term impacts of forest restoration on aquifer recharge and water resources, especially in moisture-limited regions.

  16. Evaluation of potential effects of soil available phosphorus on soil arsenic availability and paddy rice inorganic arsenic content.

    Science.gov (United States)

    Jiang, Wei; Hou, Qingye; Yang, Zhongfang; Zhong, Cong; Zheng, Guodong; Yang, Zhiqiang; Li, Jie

    2014-05-01

    The transfer of arsenic from paddy field to rice is a major exposure route of the highly toxic element to humans. The aim of our study is to explore the effects of soil available phosphorus on As uptake by rice, and identify the effects of soil properties on arsenic transfer from soil to rice under actual field conditions. 56 pairs of topsoil and rice samples were collected. The relevant parameters in soil and the inorganic arsenic in rice grains were analyzed, and then all the results were treated by statistical methods. Results show that the main factors influencing the uptake by rice grain include soil pH and available phosphorus. The eventual impact of phosphorus is identified as the suppression of As uptake by rice grains. The competition for transporters from soil to roots between arsenic and phosphorus in rhizosphere soil has been a dominant feature. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Soils as a Solution: The Potential of Rangelands to Contribute to Climate Change Mitigation

    Science.gov (United States)

    Silver, W. L.; Ryals, R.; DeLonge, M. S.; Owen, J. J.

    2015-12-01

    The majority of soil-related climate change research has focused on describing the problem - estimating rates of carbon (C) losses and greenhouse gas (GHG) emissions from natural and managed ecosystems. More research is needed to explore potential solutions to climate change through mitigation and adaptation. Here we report on an integrated set of studies aimed at critically evaluating the biogeochemical potential of rangeland soils to help mitigate climate change, while improving the sustainability and productivity of food production systems. We explored direct effects through enhanced net primary production (NPP) and soil C sequestration, and indirect effects through diversion of high emitting sources to lower emitting organic matter dynamics. We used a combination of long- and short-term field experiments, modeling, laboratory assays, life cycle assessment (LCA), and meta-analyses in consultation with a diverse group of stakeholders from both the private and public sectors. We found that organic matter amendments held particularly strong potential. Compost amendments increased soil C storage by 0.5-1.0 Mg C ha-1 y-1 in surface soils over 5 y, and increased NPP and water holding capacity. We measured 1.0 Mg of new C ha-1 y-1 over 3 y. Long-term amendment of cattle manure increased surface soil C by 19.0±7.3 Mg C ha-1 relative to unmanured fields. However, field and modeling experiments suggested that manure amendments lead to large nitrous oxide emissions that eventually eliminated CO2e benefits, whereas compost amendments continued to benefit climate for decades longer. An LCA identified a broader range of climate impacts. When scaled to an area of 25% of California's rangelands, new C sequestered following compost amendments (21 million Mg CO2e) exceeded emissions from cattle (15 million Mg CO2e); diverting organics from waste streams to amendments led to additional GHG savings. In collaboration with our partners, our research contributed to the development of

  18. Potential for Plant Growth Promotion of Rhizobacteria Associated with Salicornia Growing in Tunisian Hypersaline Soils

    Directory of Open Access Journals (Sweden)

    Francesca Mapelli

    2013-01-01

    Full Text Available Soil salinity and drought are among the environmental stresses that most severely affect plant growth and production around the world. In this study the rhizospheres of Salicornia plants and bulk soils were collected from Sebkhet and Chott hypersaline ecosystems in Tunisia. Depiction of bacterial microbiome composition by Denaturing Gradient Gel Electrophoresis unveiled the occurrence of a high bacterial diversity associated with Salicornia root system. A large collection of 475 halophilic and halotolerant bacteria was established from Salicornia rhizosphere and the surrounding bulk soil, and the bacteria were characterized for the resistance to temperature, osmotic and saline stresses, and plant growth promotion (PGP features. Twenty Halomonas strains showed resistance to a wide set of abiotic stresses and were able to perform different PGP activities in vitro at 5% NaCl, including ammonia and indole-3-acetic acid production, phosphate solubilisation, and potential nitrogen fixation. By using a gfp-labelled strain it was possible to demonstrate that Halomonas is capable of successfully colonising Salicornia roots in the laboratory conditions. Our results indicated that the culturable halophilic/halotolerant bacteria inhabiting salty and arid ecosystems have a potential to contribute to promoting plant growth under the harsh salinity and drought conditions. These halophilic/halotolerant strains could be exploited in biofertilizer formulates to sustain crop production in degraded and arid lands.

  19. The automated reference toolset: A soil-geomorphic ecological potential matching algorithm

    Science.gov (United States)

    Nauman, Travis; Duniway, Michael C.

    2016-01-01

    Ecological inventory and monitoring data need referential context for interpretation. Identification of appropriate reference areas of similar ecological potential for site comparison is demonstrated using a newly developed automated reference toolset (ART). Foundational to identification of reference areas was a soil map of particle size in the control section (PSCS), a theme in US Soil Taxonomy. A 30-m resolution PSCS map of the Colorado Plateau (366,000 km2) was created by interpolating ∼5000 field soil observations using a random forest model and a suite of raster environmental spatial layers representing topography, climate, general ecological community, and satellite imagery ratios. The PSCS map had overall out of bag accuracy of 61.8% (Kappa of 0.54, p < 0.0001), and an independent validation accuracy of 93.2% at a set of 356 field plots along the southern edge of Canyonlands National Park, Utah. The ART process was also tested at these plots, and matched plots with the same ecological sites (ESs) 67% of the time where sites fell within 2-km buffers of each other. These results show that the PSCS and ART have strong application for ecological monitoring and sampling design, as well as assessing impacts of disturbance and land management action using an ecological potential framework. Results also demonstrate that PSCS could be a key mapping layer for the USDA-NRCS provisional ES development initiative.

  20. Impact of Potentially Contaminated River Water on Agricultural Irrigated Soils in an Equatorial Climate

    Directory of Open Access Journals (Sweden)

    Juan M. Trujillo-González

    2017-06-01

    Full Text Available Globally, it is estimated that 20 million hectares of arable land are irrigated with water that contains residual contributions from domestic liquids. This potentially poses risks to public health and ecosystems, especially due to heavy metals, which are considered dangerous because of their potential toxicity and persistence in the environment. The Villavicencio region (Colombia is an equatorial area where rainfall (near 3000 mm/year and temperature (average 25.6 °C are high. Soil processes in tropical conditions are fast and react quickly to changing conditions. Soil properties from agricultural fields irrigated with river water polluted by a variety of sources were analysed and compared to non-irrigated control soils. In this study, no physico-chemical alterations were found that gave evidence of a change due to the constant use of river water that contained wastes. This fact may be associated with the climatic factors (temperature and precipitation, which contribute to fast degradation of organic matter and nutrient and contaminants (such as heavy metals leaching, or to dilution of wastes by the river.

  1. Modeling impacts of human footprint and soil variability on the potential distribution of invasive plant species in different biomes

    Science.gov (United States)

    Wan, Ji-Zhong; Wang, Chun-Jing; Yu, Fei-Hai

    2017-11-01

    Human footprint and soil variability may be important in shaping the spread of invasive plant species (IPS). However, until now, there is little knowledge on how human footprint and soil variability affect the potential distribution of IPS in different biomes. We used Maxent modeling to project the potential distribution of 29 IPS with wide distributions and long introduction histories in China based on various combinations of climatic correlates, soil characteristics and human footprint. Then, we evaluated the relative importance of each type of environmental variables (climate, soil and human footprint) as well as the difference in range and similarity of the potential distribution of IPS between different biomes. Human footprint and soil variables contributed to the prediction of the potential distribution of IPS, and different types of biomes had varying responses and degrees of impacts from the tested variables. Human footprint and soil variability had the highest tendency to increase the potential distribution of IPS in Montane Grasslands and Shrublands. We propose to integrate the assessment in impacts of human footprint and soil variability on the potential distribution of IPS in different biomes into the prevention and control of plant invasion.

  2. Biogeography and Metabolic Potential of Soil Microbial Communities Across Local Environmental Gradients Illuminated Through Metagenomics

    Science.gov (United States)

    Sharrar, A.; Diamond, S.; Butterfield, C.; Starr, E.; Thomas, B. C.; Banfield, J. F.

    2016-12-01

    Soils are extremely heterogeneous and diverse microbial habitats. The distribution of microbes and their metabolic functions in soil is important for carbon and nitrogen cycling and overall ecosystem functioning. Little is known about biogeographical patterns of microbes in soil and how they relate to different environmental gradients. To address this topic, we have obtained metagenomes from 86 soil samples taken at the Eel River Critical Zone Observatory and a nearby meadow in the northern California Angelo Coast Range Reserve over a period of two years. These samples span a variety of environmental parameters, including depth, relief, time since last rainfall, and proximity to root carbon inputs. Phylogenetic diversity and community overlap between these samples was analyzed using ribosomal protein sequence identity and scaffold coverage. Independent of genomic bins, de-replicated ribosomal protein sequences were used to identify thousands of unique organisms between datasets. Despite environmental differences, a subset of these organisms were found in every sample. The dominant phyla in this cosmopolitan subset were Proteobacteria, Actinobacteria, Gemmatimonadetes, Verrucomicrobia, Acidobacteria, and Rokubacteria. Archaea and Nitrospirae were particularly prevalent at depths below 30cm. Patterns of ribosomal protein scaffold coverage across samples was used to compare the similarity of the microbial communities. We found that location was the greatest predictor of community similarity, followed by depth. In a subset of 60 samples taken in the same meadow, sampling plot was a greater predictor of community similarity than time since last rainfall in the same year. In addition, genome-independent analyses revealed differences in the metabolic potential for functions involved in nitrogen and carbon metabolism across environmental gradients. This study will further our understanding of soil biogeography and its relationship to overall biogeochemical cycling.

  3. Topographic and physicochemical controls on soil denitrification potential in prior converted croplands located on the Delmarva Peninsula, USA

    Science.gov (United States)

    Li, X.; Mccarty, G.; Lang, M. W.; Ducey, T.; Hunt, P.; Miller, J.

    2016-12-01

    Topography and soil physiochemical characteristics exert substantial controls on denitrification in agricultural lands. In order to depict these controls at a landscape scale for decision support applications, metrics (i.e., proxies) must be developed based on commonly available geospatial data. In this study, we analyzed the combined effects of eleven topography and soil physiochemical factors, including three topographic attributes (relief, topographic wetness index, and positive openness), two soil texture indices (sand and clay), and six soil properties (soil moisture, pH, electrical conductivity, SOC, TN, and C:N ratio), on soil denitrification potential in three actively farmed crop fields that were converted from forested wetlands before 1986 (i.e., prior converted croplands). Denitrification potential was measured using denitrification enzyme activity (DEA) assays, which employed the acetylene inhibition method under two treatments - a non-nitrate and carbon limiting treatment to measure potential denitrification and a control treatment to measure the capacity for denitrification without soil amendment. Nitrate and carbon addition led to a doubling in DEA rates compared to the control treatment. Topography explained the greatest amount of variation in potential denitrification across the three sites. The relationship between topography and DEA may partly be explained through the relatively robust relationship between topography and soil moisture, texture, and carbon content. For DEA under the control treatment, soil electrical conductivity (EC) exhibited the highest correlation with denitrification capacity (i.e., r2 = 35%). Denitrification capacity and potential were higher in a dry year with low soil moisture, relative to an average year with high soil moisture, which may be caused by the substantial increase in soil EC in the dry year. However, DEA rates were less responsive to soil EC at sandy sites which tend to have low soil moisture. Results of this

  4. Organic components of nuclear wastes and their potential for altering radionuclide distribution when released to soil

    Energy Technology Data Exchange (ETDEWEB)

    McFadden, K.M.

    1980-08-01

    Normal waste processing at the Hanford operations requires the use of many organic materials, chiefly in the form of complexing agents and diluents. These organic materials and their chemical and radiolytic degradation products, have potential for complexing fission products and transuranium elements, both in the waste streams and upon infiltration into soil, perhaps influencing future sorption or migration of the nuclides. Particular complexation characteristics of various nuclides which constitute the major fission products, long-lived isotopes, and the most mobile in radioactive wastes are discussed briefly with regards to their anticipated sorption or mobility in soils. Included in the discussion are Am, Sb, Ce, Cs, Co, Cm, Eu, I, Np, Pm, Pu, Ra, Ru, Sr, Tc, U, and Zr. 107 references.

  5. In situ soil moisture and matrix potential - what do we measure?

    Science.gov (United States)

    Jackisch, Conrad; Durner, Wolfgang

    2017-04-01

    Soil moisture and matric potential are often regarded as state variables that are simple to monitor at the Darcy-scale. At the same time unproven believes about the capabilities and reliabilities of specific sensing methods or sensor systems exist. A consortium of ten institutions conducted a comparison study of currently available sensors for soil moisture and matrix potential at a specially homogenised field site with sandy loam soil, which was kept free of vegetation. In total 57 probes of 15 different systems measuring soil moisture, and 50 probes of 14 different systems measuring matric potential have been installed in a 0.5 meter grid to monitor the moisture state in 0.2 meter depth. The results give rise to a series of substantial questions about the state of the art in hydrological monitoring, the heterogeneity problem and the meaning of soil water retention at the field scale: A) For soil moisture, most sensors recorded highly plausible data. However, they do not agree in absolute values and reaction timing. For matric potential, only tensiometers were able to capture the quick reactions during rainfall events. All indirect sensors reacted comparably slowly and thus introduced a bias with respect to the sensing of soil water state under highly dynamic conditions. B) Under natural field conditions, a better homogeneity than in our setup can hardly be realised. While the homogeneity assumption held for the first weeks, it collapsed after a heavy storm event. The event exceeded the infiltration capacity, initiated the generation of redistribution networks at the surface, which altered the local surface properties on a very small scale. If this is the reality at a 40 m2 plot, what representativity have single point observations referencing the state of whole basins? C) A comparison of in situ and lab-measured retention curves marks systematic differences. Given the general practice of soil water retention parameterisation in almost any hydrological model this

  6. Evaluation of the intrinsic mtbe biodegradation potential in MTBE-contaminated soils.

    Science.gov (United States)

    Moreels, D; Bastiaens, L; Merckx, R; Ollevier, F; Diels, L; Springael, D

    2001-01-01

    MTBE has only recently being used as an octane enhancer in gasoline in Europe and is considered as a more recent groundwater contaminant on this continent. In this study we examined if during the recent contamination history, European MTBE contaminated aquifers had developed MTBE degrading microbial communities. Different MTBE contaminated and non-contaminated aquifers and soils were tested for their intrinsic biodegradation potential. The role of the oxygen concentration, the availability of nutrients and the influence of the presence of a co-contaminant like benzene on the MTBE biodegradation capabilities of the indigenous microorganisms were examined. All studied soil samples showed degradation of benzene under all tested conditions. On the other hand only one aquifer showed the capacity to degrade MTBE as demonstrated by the disappearance of MTBE and the production of TBA, the main degradation product of MTBE.

  7. Outlier identification in urban soils and its implications for identification of potential contaminated land

    Science.gov (United States)

    Zhang, Chaosheng

    2010-05-01

    Outliers in urban soil geochemical databases may imply potential contaminated land. Different methodologies which can be easily implemented for the identification of global and spatial outliers were applied for Pb concentrations in urban soils of Galway City in Ireland. Due to its strongly skewed probability feature, a Box-Cox transformation was performed prior to further analyses. The graphic methods of histogram and box-and-whisker plot were effective in identification of global outliers at the original scale of the dataset. Spatial outliers could be identified by a local indicator of spatial association of local Moran's I, cross-validation of kriging, and a geographically weighted regression. The spatial locations of outliers were visualised using a geographical information system. Different methods showed generally consistent results, but differences existed. It is suggested that outliers identified by statistical methods should be confirmed and justified using scientific knowledge before they are properly dealt with.

  8. Polar metabolites of polycyclic aromatic compounds from fungi are potential soil and groundwater contaminants

    DEFF Research Database (Denmark)

    Boll, Esther Sørensen; Johnsen, Anders R.; Christensen, Jan H.

    2015-01-01

    and either hydroxylated or oxidized to carboxylic acids at the methyl group. The metabolism of the sulfur-containing heterocyclic PAC resulted in sulfate conjugates. The sorption of the PAC metabolites to three soils was determined using a batch equilibrium method, and partition coefficients (Kd's) were......-methylphenanthrene, 1-methylpyrene), and one sulfur-containing heterocyclic PAC (dibenzothiophene). Fifty-eight metabolites were tentatively identified; metabolites from the un-substituted PACs were hydroxylated and sulfate conjugated, whereas metabolites from alkyl-substituted PACs were sulfate conjugated...... calculated for fourteen representative metabolites. Sulfate conjugated metabolites displayed Kd's below 70 whereas the metabolites with both a sulfate and a carboxylic acid group had Kd's below 2.8. The low Kd's of water-soluble PAC metabolites indicate high mobility in soil and a potential for leaching...

  9. Addressing Geographic Variability in the Comparative Toxicity Potential of Copper and Nickel in Soils

    DEFF Research Database (Denmark)

    Owsianiak, Mikolaj; Rosenbaum, Ralph K.; Huijbregts, Mark A. J.

    2013-01-01

    Comparative toxicity potentials (CTP), in life cycle impact assessment also known as characterization factors (CF), of copper (Cu) and nickel (Ni) were calculated for a global set of 760 soils. An accessibility factor (ACF) that takes into account the role of the reactive, solid-phase metal pool......% geographic variability intervals are 1.4 × 103 (1.7 × 102 to 2.0 × 104) and 1.7 × 103 (2.1 × 102 to 1.1 × 104) m3/kg·day, respectively. The geographic variability of 3.5 orders of magnitude in the CTP of Cu is mainly associated with the variability in soil organic carbon and pH. They largely influence...

  10. A Linkage Between Parent Materials of Soil and Potential Risk of Heavy Metals in Yunnan province, China

    Science.gov (United States)

    Cheng, X.

    2015-12-01

    A large area exceeding soil quality standards for heavy metals in South western China has been identified previously reported on a nationwide survey of soil pollution, yet the ecological risk of heavy metal in soil is unknown or uncertainty.To assess thoroughly the ecological risk in this region, seven soil profiles with a depth of 2m on the different parent materials of soil were conducted in Yunnan province, China, and the level of total concentrations and the fraction of water soluble, ion exchangeable, carbonates, humic acid, iron and manganese oxides and organic matter of As, Cd, Hg and Pb was investigated in soil profiles. The results indicate that parent materials of soil critically influenced the ecological risk of heavy metal.The fraction of water soluble and ion exchangeable of Cd and Hg in alluvial material and in terrigenous clastic rocks showed 2-6 times higher than those in carbonate rock; As and Pb has almost same fraction of water soluble and ion exchangeable in three parent materials of soil.The findings suggest that parent materials of soil play a critical role in ecological risk of heavy metal.Thus, more studies are needed to better understand a linkage between the parent materials of soil, different soil-forming processes and the potential risk of heavy metals under various geographic conditions, which is the key for the evaluating soil quality and food safety. Those soils with high concentration of Cd and Hg originated alluvial material and terrigenous clastic rocks need to be continuously monitored before determining a cost-effective remediation technology. Keywords: Heavy metals; Ecological risk;Parent materials of soil;China

  11. Resilience of invaded riparian landscapes: the potential role of soil-stored seed banks.

    Science.gov (United States)

    Tererai, Farai; Gaertner, Mirijam; Jacobs, Shayne M; Richardson, David M

    2015-01-01

    We investigated the potential role of soil-stored seed banks in driving vegetation recovery under varying intensities of invasion by the alien tree Eucalyptus camaldulensis along the Berg River in South Africa's Western Cape Province. We asked: How do richness, diversity, and composition of soil-stored seed banks vary with invasion intensity? What is the difference between the seed banks and above-ground vegetation with respect to species richness, diversity, composition, and structure? To what extent do soil-stored seed banks provide reliable sources for restoring native plant communities? Through a seedling-emergence approach, we compared seedling density, richness, and diversity in plots under varying Eucalyptus cover. Seed bank characteristics were also compared with those of the above-ground vegetation. Except in terms of diversity and density, the richness and composition of native species varied significantly among invasion conditions. Despite the paucity of native tree and shrub species in the seed bank, it was more diverse than extant vegetation. Some species occurred exclusively either in the seed bank or in the above-ground vegetation. Although this ecosystem has been degraded by several agents, including Eucalyptus invasion, soil-stored seed banks still offer modest potential for driving regeneration of native plant communities, but secondary invasions need to be managed carefully. Remnant populations of native plants in the above-ground vegetation remaining after E. camaldulensis clearing provide a more promising propagule source for rapid regeneration. Further work is needed to elucidate possible effects of invasion on successional pathways following E. camaldulensis removal and the effects of hydrochory on seed bank dynamics.

  12. Investigation of the photocatalytic effect of zinc oxide nanoparticles in the presence of nitrite

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Min; Abbood, Hayder A. [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074 (China); Institute of Inorganic Chemistry and Chemical Biology, Hubei key Laboratory of Bioinorganic Chemistry and Medicine, 1037 Luoyu Road, Wuhan 430074 (China); Zhu, Zhening [National Center for Nanoscience and Technology, No.11 ZhongGuanCun BeiYiTiao Road, Beijing 100190 (China); Li, Hailing [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074 (China); Institute of Inorganic Chemistry and Chemical Biology, Hubei key Laboratory of Bioinorganic Chemistry and Medicine, 1037 Luoyu Road, Wuhan 430074 (China); Gao, Zhonghong, E-mail: zhgao144@mail.hust.edu.cn [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074 (China); Institute of Inorganic Chemistry and Chemical Biology, Hubei key Laboratory of Bioinorganic Chemistry and Medicine, 1037 Luoyu Road, Wuhan 430074 (China)

    2013-01-15

    Highlights: ► Nitrite enhanced the photo-damage by ZnO nanoparticles to BSA and HaCaT cells. ► Protein nitration was induced by nitrite in photo-damaged BSA and HaCaT cells. ► The effects of photo-damage on BSA were affected by various factors. ► 50-nm ZnO induced more apoptosis than 90-nm ZnO in HaCaT cells. -- Abstract: Zinc oxide nanoparticles are widely used in sunscreen products because of their chemical stability and capability of blocking harmful ultraviolet rays. However, zinc oxide nanoparticles can also generate reactive species under ultraviolet irradiation. Because nitrite can form reactive nitrogen species under oxidative stress and because it exists in perspiration and cosmetics, we studied the effects of nitrites on the photocatalytic damage of zinc oxide nanoparticles (50 nm and 90 nm) to bovine serum albumin and human keratinocyte cells under ultraviolet irradiation (365 nm and 254 nm). The results indicate that nitrite plays an enhancing role in photocatalytic damage by breaking amino acid residues and promoting protein oxidation and nitration. The concentrations of zinc oxide and nitrite, the irradiation light and duration, and the pH of the medium are important factors influencing this photocatalytic damage. Size effects of ZnO nanoparticles on bovine serum albumin and keratinocyte cells are different. It is speculated that the extent of photo-damage is partially dependent on the aggregation of zinc oxide. These findings may be valuable for understanding potential risks of applying zinc oxide nanoparticle-containing sunscreens to human skin under sunlight exposure.

  13. Investigation of the bioremediation potential of aerobic zymogenous microorganisms in soil for crude oil biodegradation

    Directory of Open Access Journals (Sweden)

    TATJANA ŠOLEVIĆ

    2011-03-01

    Full Text Available The bioremediation potential of the aerobic zymogenous microorganisms in soil (Danube alluvium, Pančevo, Serbia for crude oil biodegradation was investigated. A mixture of paraffinic types of oils was used as the substrate. The laboratory experiment of the simulated oil biodegradation lasted 15, 30, 45, 60 and 75 days. In parallel, an experiment with a control sample was conducted. Extracts were isolated from the samples with chloroform in a separation funnel. From these extracts, the hydrocarbons were isolated by column chromatography and analyzed by gas chromatography–mass spectrometry (GC–MS. n-Alkanes, isoprenoids, phenanthrene and its derivatives with one and two methyl groups were quantitatively analyzed. The ability and efficiency of zymogenous microorganisms in soil for crude oil bioremediation was assessed by comparison between the composition of samples which were exposed to the microorganisms and the control sample. The investigated microorganisms showed the highest bioremediation potential in the biodegradation of n-alkanes and isoprenoids. A considerably high bioremediation potential was confirmed in the biodegradation of phenanthrene and methyl phenanthrenes. Low bioremediation potential of these microorganisms was proven in the case of polycyclic alkanes of the sterane and triterpane types and dimethyl phenanthrenes.

  14. The potential of agricultural practices to increase C storage in cropped soils: an assessment for France

    Science.gov (United States)

    Chenu, Claire; Angers, Denis; Métay, Aurélie; Colnenne, Caroline; Klumpp, Katja; Bamière, Laure; Pardon, Lenaic; Pellerin, Sylvain

    2014-05-01

    Though large progress has been achieved in the last decades, net GHG emissions from the agricultural sector are still more poorly quantified than in other sectors. In this study, we examined i) technical mitigation options likely to store carbon in agricultural soils, ii) their potential of additional C storage per unit surface area and iii) applicable areas in mainland France. We considered only agricultural practices being technically feasible by farmers and involving no major change in either production systems or production levels. Moreover, only currently available techniques with validated efficiencies and presenting no major negative environmental impacts were taken into account. Four measures were expected to store additional C in agricultural soils: - Reducing tillage: either a switch to continuous direct seeding, direct seeding with occasional tillage once every five years, or continuous superficial (20yrs) C storage rates (MgC ha-1 y-1,) of cropping systems with and without the proposed practice. Then we analysed the conditions for potential application, in terms of feasibility, acceptance, limitation of yield losses and of other GHG emissions. According to the literature, additional C storage rates were 0.15 (0-0.3) MgC ha-1 y-1 for continuous direct seeding, 0.10 (0-0.2) MgC ha-1 y-1for occasional tillage one year in five, and 0.0 MgC ha-1 y-1 for superficial tillage. Cover crops were estimated to store 0.24 (0.13-0.37) MgC ha-1 y-1 between cash crops and 0.49 (0.23-0.72) MgC ha-1 y-1 when associated with vineyards. Hedges (i.e 60 m ha-1) stored 0.15 (0.05-0.26) Mg C ha-1 y-1. Very few estimates were available for temperate agroforestry system, and we proposed a value of 1.01 (0.11-1.36) Mg C ha-1 y-1for C stored in soil and in the tree biomass for systems comprising 30-50 trees ha-1. Increasing the life time of temporary sown grassland increased C stocls by 0.11 (0.07-0.22) Mg C ha-1 y-1. In general, practices with increased C inputs to soil through

  15. Nitrite-free Asian hot dog sausages reformulated with nitrite replacers.

    Science.gov (United States)

    Ruiz-Capillas, C; Tahmouzi, S; Triki, M; Rodríguez-Salas, L; Jiménez-Colmenero, F; Herrero, A M

    2015-07-01

    This research deals with the application of a global strategy designed to produce a nitrite-free Asian hot dog. Different ingredients such as annatto, cochineal, orange dietary fibre, vitamins E and C, lactate and celery were combined in order to study the appearance (colour), lipid oxidation stability and microbial stability of the nitrite-free formulations. The control sample contained much more (P annatto (RA) had the lowest a* values. Lipid oxidation levels were similar irrespective of formulation. The hot dog reformulated with cochineal (RC) scored higher for overall acceptability than RA, mainly due to its colour.

  16. Pollution Assessment of Toxic and Potentially Toxic Elements in Agricultural Soils of the City Addis Ababa, Ethiopia.

    Science.gov (United States)

    Aschale, Minbale; Sileshi, Yilma; Kelly-Quinn, Mary; Hailu, Dereje

    2017-02-01

    Due to the significantly fast urban expansion and increased industrial activities, the soils in the farms in Addis Ababa are contaminated by some toxic and potentially toxic elements (As, V, Cr, Fe, Co, Ni, Cu, B, Ba, Sr, Zn, Mn, Pb and Cd) in varying degrees. The mean concentrations of Cr, Ni, As and B in most of the soil farms were found to be higher than the maximum recommended limits. The mean concentrations of Cd, Cu, Pb, Co, Ni and Mn were found to be higher than the background soil concentrations given for uncontaminated soils. Multivariate analyses coupled with correlation analysis were used to identify possible sources. The geo-accumulation index values for Cr, Mn and Pb indicated that the farm soils were unpolluted to moderately polluted as a result of anthropogenic activities. A comprehensive environmental management strategy should be formulated by the government to measure further pollution of the farmland soil.

  17. Diversity and arsenic-tolerance potential of bacterial communities from soil and sediments along a gold tailing contamination gradient

    National Research Council Canada - National Science Library

    Chi, Xiaoyuan; Jiang, Bo; Yan, Xu; Luo, Ximing; Li, Youxun; Guan, Xiangyu

    2017-01-01

    .... To reveal the effects of As on the diversity of bacterial communities and their As-tolerance potential, farmland soil and river sediment samples were collected at various distances from tailings...

  18. Nitrate-nitrite toxicity in cattle and sheep grazing Dactyloctenium radulans (button grass) in stockyards.

    Science.gov (United States)

    McKenzie, R A; Rayner, A C; Thompson, G K; Pidgeon, G F; Burren, B R

    2004-10-01

    Hungry cattle and sheep introduced to stockyards containing a dominant or pure growth of Dactyloctenium radulans (button grass) suffered acute nitrate-nitrite toxicity in four incidents in inland Queensland between 1993 and 2001. Deaths ranged from 16 to 44%. Methaemoglobinaemia was noted at necropsies in all incidents. An aqueous humour sample from one dead steer contained 75 mg nitrate/L and from one dead sheep contained 100 mg nitrate and 50 mg nitrite/L (normal = ca 5 mg nitrate/L). Both lush and dry button grass were toxic. The nitrate content of button grass from within the stockyards ranged from 4.0 to 12.9% as potassium nitrate equivalent in dry matter and from outside the stockyards ranged from stockyard soil may boost the nitrate content of button grass to a concentration hazardous to hungry ruminants.

  19. Nitrite as a physiological source of nitric oxide and a signalling molecule in the regulation of the cardiovascular system in both mammalian and non-mammalian vertebrates.

    Science.gov (United States)

    Pellegrino, Daniela; Parisella, Maria L

    2010-06-01

    The circulating anion nitrite (NO(2)(-)) has long been considered an inert oxidative metabolite of nitric oxide (NO). Over the last decade several studies have identified inorganic nitrite as a key player in many biological processes because it acts both as a principal storage source of NO and as a signalling molecule distinct from its link with NO. This new field of research involves the exploration of the molecular, biochemical, and physiological activities of nitrite under a variety of physiological and pathophysiological states. As a signalling molecule, nitrite is involved in various biological responses, including hypoxic vasodilation, inhibition of mitochondrial respiration, cytoprotection following ischemia/reperfusion and regulation of protein and gene expression. As a stored form of NO, since the cardiovascular system is under an important NO-mediated autocrine-paracrine control, intensive investigations involve nitrite effects on vessel and heart regulation. Recently, some authors have reported that nitrite, through both direct and indirect pathways, plays a fundamental role in vascular homeostasis and cardiac function not only in mammals but also in non-mammalian species (fish, amphibians). This review highlights some patents and the importance of the signalling properties of nitrite anion in a comparative vertebrate context for providing significant insights on "ancestral" functions of the nitrite-NO system, which may facilitate its potential use as a therapeutic agent of cardiovascular disease.

  20. Soil water retention at varying matric potentials following repeated wetting with modestly saline-sodic water and subsequent air drying

    Energy Technology Data Exchange (ETDEWEB)

    Browning, L.S.; Hershberger, K.R.; Bauder, J.W. [Montana State University, Bozeman, MT (United States). Dept. of Land Resources & Environmental Science

    2007-07-01

    Coal bed natural gas (CBNG) development in the Powder River (PR) Basin produces modestly saline, highly sodic wastewater. This study assessed impacts of wetting four textural groups (0-11%, 12-22%, 23 -33%, and > 33% clay (g clay/100 g soil) x 100%))with simulated PR or CBNG water on water retention. Soils received the following treatments with each water quality: a single wetting event, five wetting and drying events, or five wetting and drying events followed by leaching with salt-free water. Treated samples were then resaturated with the final treatment water and equilibrated to -10, -33, -100, -500, or -1,500 kPa. At all potentials, soil water retention increased significantly with increasing clay content. Drought-prone soils lost water-holding capacity between saturation and field capacity with repeated wetting and drying, whereas finer textured soils withstood this treatment better and had increased water-retention capacity at lower matric potentials.

  1. The role of red blood cell S-nitrosation in nitrite bioactivation and its modulation by leucine and glucose

    Directory of Open Access Journals (Sweden)

    Nadeem Wajih

    2016-08-01

    Full Text Available Previous work has shown that red blood cells (RBCs reduce nitrite to NO under conditions of low oxygen. Strong support for the ability of red blood cells to promote nitrite bioactivation comes from using platelet activation as a NO-sensitive process. Whereas addition of nitrite to platelet rich plasma in the absence of RBCs has no effect on inhibition of platelet activation, when RBCs are present platelet activation is inhibited by an NO-dependent mechanism that is potentiated under hypoxia. In this paper, we demonstrate that nitrite bioactivation by RBCs is blunted by physiologically-relevant concentrations of nutrients including glucose and the important signaling amino acid leucine. Our mechanistic investigations demonstrate that RBC mediated nitrite bioactivation is largely dependent on nitrosation of RBC surface proteins. These data suggest a new expanded paradigm where RBC mediated nitrite bioactivation not only directs blood flow to areas of low oxygen but also to areas of low nutrients. Our findings could have profound implications for normal physiology as well as pathophysiology in a variety of diseases including diabetes, sickle cell disease, and arteriosclerosis.

  2. Low nitrous oxide production through nitrifier-denitrification in intermittent-feed high-rate nitritation reactors.

    Science.gov (United States)

    Su, Qingxian; Ma, Chun; Domingo-Félez, Carlos; Kiil, Anne Sofie; Thamdrup, Bo; Jensen, Marlene Mark; Smets, Barth F

    2017-10-15

    Nitrous oxide (N2O) production from autotrophic nitrogen conversion processes, especially nitritation systems, can be significant, requires understanding and calls for mitigation. In this study, the rates and pathways of N2O production were quantified in two lab-scale sequencing batch reactors operated with intermittent feeding and demonstrating long-term and high-rate nitritation. The resulting reactor biomass was highly enriched in ammonia-oxidizing bacteria, and converted ∼93 ± 14% of the oxidized ammonium to nitrite. The low DO set-point combined with intermittent feeding was sufficient to maintain high nitritation efficiency and high nitritation rates at 20-26 °C over a period of ∼300 days. Even at the high nitritation efficiencies, net N2O production was low (∼2% of the oxidized ammonium). Net N2O production rates transiently increased with a rise in pH after each feeding, suggesting a potential effect of pH on N2O production. In situ application of 15N labeled substrates revealed nitrifier denitrification as the dominant pathway of N2O production. Our study highlights operational conditions that minimize N2O emission from two-stage autotrophic nitrogen removal systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. [Assessment of heavy metal pollution and potential ecological risks of urban soils in Kaifeng City, China].

    Science.gov (United States)

    Li, Yi-Meng; Ma, Jian-Hua; Liu, De-Xin; Sun, Yan-Li; Chen, Yan-Fang

    2015-03-01

    Ninety-nine topsoil (0-15 cm) samples were collected from Kaifeng City, China using the grid method, and then the concentrations of As, Cd, Cr, Cu, Ni, Pb and Zn in the samples were measured by standard methods. Soil pollution levels and potential ecological risks of the heavy metals were assessed using the pollution load index (PLI) and potential ecological risk index (RI), respectively. Ordinary Kriging interpolation technique was employed to investigate the spatial distribution of PLI and RI of the city. The results showed that high pollution of Cd occurred in Kaifeng urban soils, and there was moderate pollution of Zn, slight pollution of Pb and Cu, and no pollution of Ni, Cr and As. Very high ecological risk was posed by Cd and low risk by other metals. The mean PLI of the 7 metals from all sample points was 2.53, which was categorized as moderate pollution. The average RI was 344.58 which represented a considerable ecological risk. PLI and RI shared a similar spatial distribution with high values centralized in the old industrial area in the southeast and railway stations for passengers and goods in the south of the city, followed by the old town within the ancient city wall, and low values located in the north and west areas. Cadmium was the main factor for both soil pollution and potential ecological risk primarily due to farmland topsoil in the eastern suburb of Kaifeng City with high Cd concentrations resulted from sewage irrigation deposited in the urban area by wind, human activities such as soot discharged from the chemical fertilizer plant of Kaifeng, transportation and coal combustion.

  4. Health risk implications of potentially toxic metals in street dust and surface soil of Tehran, Iran.

    Science.gov (United States)

    Dehghani, Sharareh; Moore, Farid; Keshavarzi, Behnam; Hale, Beverley A

    2017-02-01

    In this study a total of 30 street dusts and 10 surface soils were collected in the central district of Tehran and analyzed for major potentially toxic metals. Street dust was found to be greatly enriched in Sb, Pb, Cu and Zn and moderately enriched in Cr, Mn, Mo and Ni. Contamination of Cu, Sb, Pb and Zn was clearly related to anthropogenic sources such as brake wear, tire dust, road abrasion and fossil fuel combustion. Spatial distribution of pollution load index in street dust suggested that industries located south-west of the city intensify street dust pollution. Microscopic studies revealed six dominant group of morphological structures in calculation of the exposurethe street dusts and surface soils, with respect to different geogenic and anthropogenic sources. The BCR (the European Community Bureau of Reference) sequential extraction results showed that Sb, Ni, Mo, As and Cr bonded to silicates and sulfide minerals were highly resistant to dissolution. In contrast, Zn, Cd, and Mn were mostly associated with the exchangeable phase and thus would be easily mobilized in the environment. Cu was the most abundant metal in the reducible fraction, indicating its adsorption to iron and manganese oxy-hydroxides. Pb was equally extracted from exchangeable and reducible fractions. Anthropogenic sources related to traffic apparently play a small role in Cr, Ni and Mo contamination and dispersed them as bioavailable forms but with reduced mobility and bioavailablity due to high potential of complexation and adsorption to organic matter and iron and manganese oxy-hydroxides. Calculated Hazard Index (HI) suggests ingestion as the most important pathway for the majority of PTMs in children and dermal contact as the main exposure route for Cr, Cd and Sb for adults. The HIs and fractionation pattern of elements revealed Pb as the sole element that bears potential health risk in street dust and surface soil. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Neotyphodium coenophialum-infected tall fescue and its potential application in the phytoremediation of saline soils.

    Science.gov (United States)

    Yin, L; Ren, A; Wei, M; Wu, L; Zhou, Y; Li, X; Gao, Y

    2014-01-01

    The growth response of endophyte-infected (EI) and endophyte-free (EF) tall fescue to salt stress was investigated under two growing systems (hydroponic and soil in pots). The hydroponic experiment showed that endophyte infection significantly increased tiller and leaf number, which led to an increase in the total biomass of the host grass. Endophyte infection enhanced Na accumulation in the host grass and improved Na transport from the roots to the shoots. With a 15 g l(-1) NaCl treatment, the phytoextraction efficiency of EI tall fescue was 2.34-fold higher than EF plants. When the plants were grown in saline soils, endophyte infection also significantly increased tiller number, shoot height and the total biomass of the host grass. Although EI tall fescue cannot accumulate Na to a level high enough for it to be termed a halophyte, the increased biomass production and stress tolerance suggested that endophyte/plant associations had the potential to be a model for endophyte-assisted phytoextraction in saline soils.

  6. Metal tolerance potential of filamentous fungi isolated from soils irrigated with untreated municipal effluent

    Directory of Open Access Journals (Sweden)

    Shazia Akhtar, Muhammad Mahmood-ul-Hassan, Rizwan Ahmad, Vishandas Suthor and Muhammad Yasin

    2013-05-01

    Full Text Available Considering the importance of filamentous fungi for bioremediation of wastewater and contaminated soils, this study was planned to investigate the metal tolerance potential of indigenous filamentous fungi. Nineteen fungal strains were isolated from soils irrigated with untreated municipal/industrial effluent using dilution technique and 10 prominent isolates were used for metal tolerance. The isolated fungal isolates were screened for metal tolerance index (MTI at I mM cadmium (Cd, nickel (Ni and copper (Cu concentrations and for minimum inhibitory concentration (MIC and metal tolerance by growing on potato dextrose agar plates amended with varying amounts of Cd, Cu and Ni. Seven out of 10 isolated fungi belonged to the genera Aspergillus and three belonged to Curvularia, Acrimonium and Pithyum. The results revealed that the order of tolerance of isolates for metals was Cd > Cu > Ni and Aspergillus sp. were more tolerant than other fungi. Tolerance ranged from 900 – 9218 mg L-1 for Cd, followed by 381 - 1780 mg L-1 for Cu and 293-1580 mg L-1for Ni. The isolated fungi exhibiting great tolerance to metals (Cd, Cu and Ni can be used successfully for bioremediation of metals from contaminated soil and wastewaters.

  7. Potential of miscanthus biochar to improve sandy soil health, in situ nickel immobilization in soil and nutritional quality of spinach.

    Science.gov (United States)

    Khan, Waqas-Ud-Din; Ramzani, Pia Muhammad Adnan; Anjum, Shazia; Abbas, Farhat; Iqbal, Muhammad; Yasar, Abdullah; Ihsan, Muhammad Zahid; Anwar, Muhammad Naveed; Baqar, Mujtaba; Tauqeer, Hafiz Muhammad; Virk, Zaheer Abbas; Khan, Shahbaz Ali

    2017-10-01

    The complex interaction of biochar (BC) with soil health reflecting properties, the feedstock used to prepare BC and application rate of BC in sandy soil is still a question for the researchers. An incubation study was conducted where nine different sorts of BC, each prepared from the different feedstock, were applied at 2% rate to evaluate their relative suitability to improve sandy soil health. Results revealed that BC prepared from miscanthus (MIB) significantly increased soil medium and fine pores, available water content (AWC), electrical conductivity (EC), and cation exchange capacity (CEC) while decreased soil wide pores, pH, bulk density (BD) and particle density (PD) compared to the rest sorts of BC. Later, spinach was grown in pots containing same soil but spiked with 50 ppm nickel (Ni) and amended with 1, 2, 3, 4 and 5% rates of MIB. The results showed a significant increment in spinach biomass, reduction in the concentrations of Ni in spinach tissues and DTPA-extractable Ni with the increasing rate of MIB till 3% and later, no significant changes with 4 and 5% rates thereafter. However, significant improvement in the activities of antioxidant enzymes, chemical and biochemical attributes of spinach were observed at 5% MIB when compared to lower rates. Similarly, post-harvest soil physicochemical and enzymatic parameters were also significantly (P spinach, sandy soil health and can reduce Ni concentrations in spinach tissues. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Changes in oxidative potential of soil and fly ash after reaction with gaseous nitric acid

    Science.gov (United States)

    Zhan, Ying; Ginder-Vogel, Matthew; Shafer, Martin M.; Rudich, Yinon; Pardo, Michal; Katra, Itzhak; Katoshevski, David; Schauer, James J.

    2018-01-01

    The goal of this study was to examine the impact of simulated atmospheric aging on the oxidative potential of inorganic aerosols comprised primarily of crustal materials. Four soil samples and one coal fly ash sample were artificially aged in the laboratory through exposure to the vapor from 15.8 M nitric acid solution for 24 h at room temperature. Native and acid-aged samples were analyzed with a cellular macrophage and acellular dithionthreitol assays to determine oxidative potential. Additionally, the samples were analyzed to determine the concentration of 50 elements, both total and the water-soluble fraction of these elements by Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICMS) and crystalline mineral composition using X-ray Diffraction (XRD). The results show that reactions with gaseous nitric acid increase the water-soluble fraction of many elements, including calcium, iron, magnesium, zinc, and lead. The mineral composition analysis documented that calcium-rich minerals present in the soils (e.g., calcite) are converted into different chemical forms, such as calcium nitrate (Ca(NO3)2). The nitric acid aging process, which can occur in the atmosphere, leads to a 200-600% increase in oxidative potential, as measured by cellular and acellular assays. This laboratory study demonstrates that the toxic effects of aged versus freshly emitted atmospheric dust may be quite different. In addition, the results suggest that mineralogical analysis of atmospheric dust may be useful in understanding its degree of aging.

  9. Evaluation of leaching potential of three systemic neonicotinoid insecticides in vineyard soil

    Science.gov (United States)

    Kurwadkar, Sudarshan; Wheat, Remington; McGahan, Donald G.; Mitchell, Forrest

    2014-12-01

    Dinotefuran (DNT), imidacloprid (IMD), and thiamethoxam (THM) are commonly used neonicotinoid insecticides in a variety of agriculture operations. Although these insecticides help growers control pest infestation, the residual environmental occurrence of insecticides may cause unintended adverse ecological consequences to non-target species. In this study, the leaching behavior of DNT, IMD, and THM was investigated in soils collected from an active AgriLife Research Extension Center (AREC) vineyard. A series of column experiments were conducted to evaluate the leaching potential of insecticides under two experimental scenarios: a) individual pulse mode, and b) mixed pulse mode. In both scenarios, the breakthrough pattern of the insecticides in the mostly acidic to neutral vineyard soil clearly demonstrates medium to high leachability. Of the three insecticides studied for leaching, DNT has exhibited high leaching potential and exited the column with fewer pore volumes, whereas IMD was retained for longer, indicating lower leachability. Relative differences in leaching behavior of neonicotinoids could be attributed to their solubility with the leaching pattern IMD neonicotinoid insecticides based on the leachability indices such as groundwater ubiquity score, relative leaching potential, and partitioning between different environmental matrices through a fugacity-based equilibrium criterion model clearly indicates that DNT may pose a greater threat to aquatic resources compared to IMD and THM.

  10. Digital Soil Mapping in the Absence of Field Training Data: A Case Study Using Terrain Attributes and Semiautomated Soil Signature Derivation to Distinguish Ecological Potential

    Directory of Open Access Journals (Sweden)

    Dawn M. Browning

    2011-01-01

    Full Text Available Spatially explicit data for soil properties governing plant water availability are needed to understand mechanisms influencing plant species distributions and predict plant responses to changing climate. This is especially important for arid and semiarid regions. Spatial data representing surrogates for soil forming factors are becoming widely available (e.g., spectral and terrain layers. However, field-based training data remain a limiting factor, particularly across remote and extensive drylands. We present a method to map soils with Landsat ETM+ imagery and high-resolution (5 m terrain (IFSAR data based on statistical properties of the input data layers that do not rely on field training data. We then characterize soil classes mapped using this semiautomated technique. The method distinguished spectrally distinct soil classes that differed in subsurface rather than surface properties. Field evaluations of the soil classification in conjunction with analysis of long-term vegetation dynamics indicate the approach was successful in mapping areas with similar soil properties and ecological potential.

  11. A low-cost electronic tensiometer system for continuous monitoring of soil water potential

    Directory of Open Access Journals (Sweden)

    Martin Thalheimer

    2013-12-01

    Full Text Available A low cost system for measuring soil water potential and data logging was developed on the basis of an Arduino microcontroller board, electronic pressure transducers and water-filled tensiometers. The assembly of this system requires only minimal soldering, limited to the wiring of the power supply and the pressure sensors to the microcontroller board. The system presented here is, therefore, not only inexpensive, but also suited for easy reproduction by users with only basic technical skills. The utility and reliability of the system was tested in a commercial apple orchard.

  12. Soil bacteria showing a potential of chlorpyrifos degradation and plant growth enhancement

    Directory of Open Access Journals (Sweden)

    Shamsa Akbar

    Full Text Available ABSTRACT Background: Since 1960s, the organophosphate pesticide chlorpyrifos has been widely used for the purpose of pest control. However, given its persistence and toxicity towards life forms, the elimination of chlorpyrifos from contaminated sites has become an urgent issue. For this process bioremediation is the method of choice. Results: Two bacterial strains, JCp4 and FCp1, exhibiting chlorpyrifos-degradation potential were isolated from pesticide contaminated agricultural fields. These isolates were able to degrade 84.4% and 78.6% of the initial concentration of chlorpyrifos (100 mg L-1 within a period of only 10 days. Based on 16S rRNA sequence analysis, these strains were identified as Achromobacter xylosoxidans (JCp4 and Ochrobactrum sp. (FCp1. These strains exhibited the ability to degrade chlorpyrifos in sterilized as well as non-sterilized soils, and were able to degrade 93-100% of the input concentration (200 mg kg-1 within 42 days. The rate of degradation in inoculated soils ranged from 4.40 to 4.76 mg-1 kg-1 d-1 with rate constants varying between 0.047 and 0.069 d-1. These strains also displayed substantial plant growth promoting traits such as phosphate solubilization, indole acetic acid production and ammonia production both in absence as well as in the presence of chlorpyrifos. However, presence of chlorpyrifos (100 and 200 mg L-1 was found to have a negative effect on indole acetic acid production and phosphate solubilization with percentage reduction values ranging between 2.65-10.6% and 4.5-17.6%, respectively. Plant growth experiment demonstrated that chlorpyrifos has a negative effect on plant growth and causes a decrease in parameters such as percentage germination, plant height and biomass. Inoculation of soil with chlorpyrifos-degrading strains was found to enhance plant growth significantly in terms of plant length and weight. Moreover, it was noted that these strains degraded chlorpyrifos at an increased rate (5

  13. Nitrite-dependent vasodilation is facilitated by hypoxia and is independent of known NO-generating nitrite reductase activities

    DEFF Research Database (Denmark)

    Dalsgaard, Thomas; Simonsen, Ulf; Fago, Angela

    2007-01-01

    The reduction of circulating nitrite to nitric oxide (NO) has emerged as an important physiological reaction aimed to increase vasodilation during tissue hypoxia. Although hemoglobin, xanthine oxidase, endothelial NO synthase, and the bc(1) complex of the mitochondria are known to reduce nitrite...... target for vasoactive NO), and known nitrite reductase activities under hypoxia. Vasodilation followed overall first-order dependency on nitrite concentration and, at low oxygenation and norepinephrine levels, was induced by low-nitrite concentrations, comparable to those found in vivo. The vasoactive...... effect of nitrite during hypoxia was abolished on inhibition of soluble guanylate cyclase and was unaffected by removal of the endothelium or by inhibition of xanthine oxidase and of the mitochondrial bc(1) complex. In the presence of hemoglobin and inositol hexaphosphate (which increases the fraction...

  14. Comparative analysis of nitrite uptake and hemoglobin-nitrite reactions in erythrocytes: sorting out uptake mechanisms and oxygenation dependencies

    DEFF Research Database (Denmark)

    Jensen, Frank Bo; Rohde, Sabina

    2010-01-01

    (hagfish and lamprey) anion exchanger-1 (AE1) in the membrane, with the aim to unravel the mechanisms and oxygenation dependencies of nitrite transport. Added nitrite rapidly diffused into the RBCs until equilibrium. The distribution ratio of nitrite across the membrane agreed with that expected from HNO2...... diffusion and AE1-mediated facilitated NO2- diffusion. Participation of HNO2 diffusion was emphasized by rapid transmembrane nitrite equilibration also in the natural AE1 knockouts. Following the equilibration, nitrite was consumed by reacting with Hb, which created a continued inward diffusion controlled....... We propose a model for RBC nitrite uptake that involves both HNO2 diffusion and AE1-mediated transport and which explains both the present and previous (sometimes puzzling) results....

  15. Hypoxia tolerance, nitric oxide, and nitrite

    DEFF Research Database (Denmark)

    Fago, Angela; Jensen, Frank Bo

    2015-01-01

    survival resides in concerted physiological responses, including strong metabolic depression, protection against oxidative damage and – in air breathing animals - redistribution of blood flow. Each of these responses is known to be tightly regulated by nitric oxide (NO) and during hypoxia by its metabolite...... of NO and nitrite signaling in the adaptive response to hypoxia in vertebrate animals.......Among vertebrates able to tolerate periods of oxygen deprivation, the painted and red-eared slider turtles (Chrysemys picta and Trachemys scripta) and the crucian carp (Carassius carassius) are the most extreme and can survive even months of total lack of oxygen during winter. The key to hypoxia...

  16. Crude oil degradation potential of bacteria isolated from oil-polluted soil and animal wastes in soil amended with animal wastes

    Directory of Open Access Journals (Sweden)

    Voke O. Urhibo

    2017-03-01

    Full Text Available The influence of animal wastes on crude oil degradation potential of strains of Proteus vulgaris and Bacillus subtilis isolated from animal wastes (poultry and pig droppings and petroleum-polluted soil was compared in laboratory studies. Both bacterial strains were selected for high crude oil degradation ability after screening many isolates by the 2,6-dichlorophenol indophenol method. Analyses by gas chromatography (GC showed that degradation of crude oil was markedly enhanced (88.3–97.3% vs 72.1–78.8% in soil amended with animal wastes as indicated by the reduction of total petroleum hydrocarbon (TPH. TPH reduction by animal waste bacterial strains in animal waste-amended soil was more than the reduction by strains from soil contaminated with petroleum (P < 0.001. The greatest reduction of TPH (96.6–97.3% vs 80.4–95.9% was by poultry waste strains and it occurred in soil amended with poultry waste. GC analyses of n-alkanes showed that although shorter chains were preferentially degraded [32.0–78.5% (C8–23 vs 6.3–18.5% (C24–36] in normal soil, biodegradation of longer chains increased to 38.4–46.3% in animal waste-amended soil inoculated with the same animal wastes’ strains. The results indicate that these animal waste strains may be of potential application for bioremediation of oil-polluted soil in the presence of the wastes from where they were isolated.

  17. Molecular identification and potential of an isolate of white rot fungi in bioremediation of petroleum contaminated soils

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    Maryam Mohammadi-sichani

    2017-06-01

    Full Text Available Introduction:Elimination or reduction of petroleum hydrocarbons from natural resources such as water and soil is a serious problem of countries, particularly oil-rich countries of the world. Using white rotting fungi compost for bioremediation of soils contaminated by petroleum hydrocarbons is effective. The aim of this study is molecular identification and potential of anisolate of white rot fungi in bioremediation of petroleum contaminated soils. Materials and methods: Spent compost of white rotting fungi was inoculated with petroleum contaminated soil into 3%, 5% and 10% (w/w. Treatments were incubated at 25-23 °C for 3 months. Reduction of petroleum hydrocarbons in treated soil was determined by gas chromatography. Ecotoxicity of soil was evaluated by seed germination test. Results: Based on the genome sequence of 18s rRNA, it is revealed that this isolate is Ganoderma lucidum and this isolate is deposited as accession KX525204 in the Gene Bank database. Reduction of petroleum hydrocarbons in soil treated with compost (3, 5 and 10% ranged from 42% to 71%. The germination index (% in ecotoxicity tests ranged from 20.8% to 70.8%. Gas chromatography results also showed a decrease in soil Hydrocarbons compounds. Discussion and conclusion: The compost of Ganoderma lucidum, a white rot fungus, has a potential ability to remove petroleum hydrocarbons in contaminated soil. Removal of hydrocarbons was increased with increase in compost mixed with contaminated soil. Petroleum contaminated soil amended with spent compost of G.lucidum 10% during three months is appropriate to remove this pollutant.

  18. Relevance of Radiocaesium Interception Potential (RIP) on a worldwide scale to assess soil vulnerability to 137Cs contamination.

    Science.gov (United States)

    Vandebroek, Louis; Van Hees, May; Delvaux, Bruno; Spaargaren, Otto; Thiry, Yves

    2012-02-01

    The extent of radiocaesium retention in soil is important to quantify the risk of further foodchain contamination. The Radiocaesium Interception Potential (RIP -Cremers et al., 1988, Nature 335, 247-249) is an intrinsic soil parameter which can be used to categorize soils or minerals in terms of their capacity to selectively adsorb radiocaesium. In this study, we measured RIP for a large soil collection (88 soil samples) representative of major FAO soil reference groups on a worldwide scale and tested the possibility to predict the RIP on the basis of other easily accessible or measurable soil data. We also compared RIP values with those obtained from separate chemical extraction experiments. The range of measured RIP values (1.8-13300 mmol kg(-1)) was shown to include nearly all possible cases of agricultural soil contamination. Only Podzols, Andosols and Ferralsols were clearly characterized by a very low RIP (<2000 mmol kg(-1)). On a worldwide scale, RIP was in fact slightly related to soil reference type or other simple major physicochemical parameters such as clay percentage or organic matter. Conversely our results indicated a link between the RIP and radiocaesium extractability across very different soils. We showed that, with the proposed scale of RIP values, a simple acid extraction method can provide an operational result highly predictive of potential RIP despite very contrasting soil properties. The RIP could be estimated from the empirical equation: RIP = (-31.701 ∗ log(AER) + 58.886)(2) where AER is the fraction of acid-extractable radiocaesium. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Biodegradation and bioremediation potential of diazinon-degrading Serratia marcescens to remove other organophosphorus pesticides from soils.

    Science.gov (United States)

    Cycoń, Mariusz; Żmijowska, Agnieszka; Wójcik, Marcin; Piotrowska-Seget, Zofia

    2013-03-15

    The ability of diazinon-degrading Serratia marcescens to remove organophosphorus pesticides (OPPs), i.e. chlorpyrifos (CP), fenitrothion (FT), and parathion (PT) was studied in a mineral salt medium (MSM) and in three soils of different characteristics. This strain was capable of using all insecticides at concentration of 50 mg/l as the only carbon source when grown in MSM, and 58.9%, 70.5%, and 82.5% of the initial dosage of CP, FT, and PT, respectively was degraded within 14 days. The biodegradation experiment showed that autochthonous microflora in all soils was characterized by a degradation potential of all tested OPPs; however, the initial lag phases for degradation of CP and FT, especially in sandy soil, were observed. During the 42-day experiment, 45.3%, 61.4% and 72.5% of the initial dose of CP, FT, and PT, respectively, was removed in sandy soil whereas the degradation of CP, FT, and PT in the same period, in sandy loam and silty soils reached 61.4%, 79.7% and 64.2%, and 68.9%, 81.0% and 63.6%, respectively. S. marcescens introduced into sterile soils showed a higher degradation potential (5-13%) for OPPs removal than those observed in non-sterile soil with naturally occurring attenuation. Inoculation of non-sterile soils with S. marcescens enhanced the disappearance rates of all insecticides, and DT50 for CP, FT, and PT was reduced by 20.7, 11.3 and 13.0 days, and 11.9, 7.0 and 8.1 days, and 9.7, 14.5 and 12.6 days in sandy, sandy loam, and silty soils, respectively, in comparison with non-sterile soils with only indigenous microflora. This ability of S. marcescens makes it a suitable strain for bioremediation of soils contaminated with OPPs. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Soil DNA metabarcoding and high-throughput sequencing as a forensic tool: considerations, potential limitations and recommendations.

    Science.gov (United States)

    Young, J M; Austin, J J; Weyrich, L S

    2017-02-01

    Analysis of physical evidence is typically a deciding factor in forensic casework by establishing what transpired at a scene or who was involved. Forensic geoscience is an emerging multi-disciplinary science that can offer significant benefits to forensic investigations. Soil is a powerful, nearly 'ideal' contact trace evidence, as it is highly individualistic, easy to characterise, has a high transfer and retention probability, and is often overlooked in attempts to conceal evidence. However, many real-life cases encounter close proximity soil samples or soils with low inorganic content, which cannot be easily discriminated based on current physical and chemical analysis techniques. The capability to improve forensic soil discrimination, and identify key indicator taxa from soil using the organic fraction is currently lacking. The development of new DNA sequencing technologies offers the ability to generate detailed genetic profiles from soils and enhance current forensic soil analyses. Here, we discuss the use of DNA metabarcoding combined with high-throughput sequencing (HTS) technology to distinguish between soils from different locations in a forensic context. Specifically, we provide recommendations for best practice, outline the potential limitations encountered in a forensic context and describe the future directions required to integrate soil DNA analysis into casework. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Evidence for occurrence, persistence, and growth potential of Escherichia coli and enterococci in Hawaii’s soil environments

    Science.gov (United States)

    Byappanahalli, Muruleedhara N.; Roll, Bruce M.; Fujioka, Roger S.

    2012-01-01

    High densities of Escherichia coli and enterococci are common in freshwaters on Oahu and other Hawaiian Islands. Soil along stream banks has long been suspected as the likely source of these bacteria; however, the extent of their occurrence and distribution in a wide range of soils remained unknown until the current investigation. Soil samples representing the seven major soil associations were collected on the island of Oahu and analyzed for fecal coliforms, E. coli, and enterococci by the most probable number method. Fecal coliforms, E. coli, and enterococci were found in most of the samples analyzed; log mean densities (MPN ± SE g soil−1) were 1.96±0.18, n=61; 1.21±0.17, n=57; and 2.99±0.12, n=62, respectively. Representative, presumptive cultures of E. coli and enterococci collected from the various soils were identified and further speciated using the API scheme; at least six species of Enterococcus, including Enterococcus faecalis and Enterococcus faecium, were identified. In mesocosm studies, E. coli and enterococci increased by 100-fold in 4 days, after mixing sewage-spiked soil (one part) with autoclaved soil (nine parts). E. coli remained metabolically active in the soil and readily responded to nutrients, as evidenced by increased dehydrogenase activity. Collectively, these findings indicate that populations of E. coli and enterococci are part of the natural soil microflora, potentially influencing the quality of nearby water bodies.

  2. Growth and invasive potential of Sapium sebiferum (Euphorbiaceae) within the coastal prairie region: the effects of soil and moisture regime

    Science.gov (United States)

    Barrilleaux, T.C.; Grace, J.B.

    2000-01-01

    The introduced tree Sapium sebiferum (Euphorbiaceae) is considered a serious threat to the preservation of the coastal prairie region of Louisiana and Texas, although it is currently uncommon in the western part of the region. The objective of this study was to evaluate the potential effects of location, soils, and available moisture on the growth and survival of S. sebiferum in coastal prairie. In a field experiment, S. sebiferum mortality was significantly greater at a western site than at central and eastern sites. The greatest mortality and least growth of surviving plants occurred on a soil from the western region, regardless of site. A greenhouse study also found that S. sebiferum growth was lowest on the western soil. Watering frequency significantly affected S. sebiferum growth, except on the western soil. Sapium sebiferum growth responded to both nitrogen and phosphorum additions for all soils. Soil analyses revealed the highest sand, sodium, and phosphorus contents, and much higher electrical conductivity in the western soil. It is concluded that the soil examined from the western region is unfavorable for S. sebiferum growth, though not to the extent to preclude S. sebiferum completely. Evidence suggests that soil salinity may be the primary cause of the poor S. sebiferum growth at the western site.

  3. Emerging insights on Brazilian Pepper tree (Schinus terebinthifolius invasion : the potential role of soil microorganisms

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    Karim eDawkins

    2016-05-01

    Full Text Available Invasive plant species constitute a major ecological and economic problem worldwide, often distorting trophic levels and ecosystem balance. Numerous studies implicate factors ranging from environmental plasticity, competition for nutrient and space, and allelopathy in the success of invasive species in general. The Brazilian Pepper tree (BP was introduced to the United States in the 1800s and has since become a category one invasive plant in Florida. It has aggressively spread to about 3000 km2 of terrestrial surface, fueled in part by the prevalence of the hybrid genotypes and environmental perturbations. It displays some of the well-established invasive mechanisms but there is a serious dearth of knowledge on the plant-microbe-soil interactions and whether the rhizobiome plays any roles in the displacement of native flora and the range expansion of BP. Several control measures, including chemical, mechanical and biological antagonism have been used with limited success while restoration of natives in soils from which BP was removed has proved problematic partly due to a poorly understood phenomenon described as the BP legacy effect. Emerging evidence suggests that allelopathy, selective recruitment of beneficial soil microbes, disruption of microbial community structure and alteration of nutrient cycling, exhibited by many other invasive plant species may also be involved in the case of BP. This brief review discusses the well-established BP invasion mechanisms and highlights the current understanding of the molecular, below-ground processes. It also points out the gaps in studies on the potential role of microbial interactions in the success of BP invasion. These hitherto poorly studied mechanisms could further explain the aggressive spread of BP and could potentially contribute significantly to effective control measures and enable appropriate strategies for restoring native plants. The review advocates for the use of cutting-edge techniques

  4. Emerging Insights on Brazilian Pepper Tree (Schinus terebinthifolius) Invasion: The Potential Role of Soil Microorganisms

    Science.gov (United States)

    Dawkins, Karim; Esiobu, Nwadiuto

    2016-01-01

    Invasive plant species constitute a major ecological and economic problem worldwide, often distorting trophic levels and ecosystem balance. Numerous studies implicate factors ranging from environmental plasticity, competition for nutrient and space, and allelopathy in the success of invasive species in general. The Brazilian Pepper tree (BP) was introduced to the United States in the 1800s and has since become a category one invasive plant in Florida. It has aggressively spread to about 3000 km2 of terrestrial surface, fueled in part by the prevalence of the hybrid genotypes and environmental perturbations. It displays some of the well-established invasive mechanisms but there is a serious dearth of knowledge on the plant–microbe–soil interactions and whether the rhizobiome plays any roles in the displacement of native flora and the range expansion of BP. Several control measures, including chemical, mechanical, and biological antagonism have been used with limited success while restoration of natives in soils from which BP was removed has proved problematic partly due to a poorly understood phenomenon described as the “BP legacy effect.” Emerging evidence suggests that allelopathy, selective recruitment of beneficial soil microbes, disruption of microbial community structure and alteration of nutrient cycling, exhibited by many other invasive plant species may also be involved in the case of BP. This brief review discusses the well-established BP invasion mechanisms and highlights the current understanding of the molecular, below-ground processes. It also points out the gaps in studies on the potential role of microbial interactions in the success of BP invasion. These hitherto poorly studied mechanisms could further explain the aggressive spread of BP and could potentially contribute significantly to effective control measures and enable appropriate strategies for restoring native plants. The review advocates for the use of cutting-edge techniques in

  5. A low cost micro-station to monitor soil water potential for irrigation management

    Science.gov (United States)

    Vannutelli, Edoardo; Masseroni, Daniele; Facchi, Arianna; Gandolfi, Claudio; Renga, Filippo

    2014-05-01

    The RISPArMiA project (which stands for "reduction of water wastage through the continuous monitoring of agri-environmental parameters") won in 2013 the contest called "LINFAS - The New Ideas Make Sustainable Agriculture" and sponsored by two Italian Foundations (Fondazione Italiana Accenture and Fondazione Collegio Università Milanesi). The objective of the RISPArMiA project is to improve the irrigation efficiency at the farm scale, by providing the farmer with a valuable decision support system for the management of irrigation through the use of low-cost sensors and technologies that can easily be interfaced with Mobile devices. Through the installation of tensiometric sensors within the cropped field, the soil water potential can be continuously monitored. Using open hardware electronic platforms, a data-logger for storing the measured data will be built. Data will be then processed through a software that will allow the conversion of the monitored information into an irrigation advice. This will be notified to the farmer if the measured soil water potential exceed literature crop-specific tensiometric thresholds. Through an extrapolation conducted on the most recent monitored data, it will be also possible to obtain a simple soil water potential prevision in absence of rain events. All the information will be sent directly to a virtual server and successively on the farmer Mobile devices. Each micro-station is completely autonomous from the energy point of view, since it is powered by batteries recharged by a solar panel. The transmission modulus consists of a GSM apparatus with a SIM card. The use of free platforms (Arduino) and low cost sensors (Watermark 200SS tensiometers and soil thermocouples) will significantly reduce the costs of construction of the micro-station which are expected to be considerably lower than those required for similar instruments on the market today . Six prototype micro-stations are actually under construction. Their field testing

  6. Fertirrigation with sugarcane vinasse: Foreseeing potential impacts on soil and water resources through vinasse characterization.

    Science.gov (United States)

    Fuess, Lucas T; Rodrigues, Isabella J; Garcia, Marcelo L

    2017-09-19

    This paper reports the characterization of the polluting potential of sugarcane vinasse, the main wastewater from ethanol production. Compositional data from vinasse samples collected from sugarcane biorefineries were used to predict negative effects on the soil, water resources and crops potentially associated with fertirrigation, the primary final destination of vinasse in Brazil. High risks of soil salinization were associated with the land disposal of vinasse, as evidenced by the high levels of total dissolved solids (TDS; >4,000 mg L -1 ) and electrical conductivity (>6.7 dS m -1 ). The high TDS levels coupled with the high biodegradable organic content of vinasse (>14 g L -1 ) also favor organic overloading events, leading to local anaerobiosis conditions. Conversely, soil sodification should not be observed in areas fertirrigated with sugarcane vinasse, given the low Na concentrations (145.1 mg L -1 ) and Ca (>458.4 mg L -1 ) levels. Priority pollutants (Cu, Cr, Ni, Pb and Zn) and phytotoxic elements (Al and Fe) were also found in the analyzed samples; however, relevant environmental impacts should not be associated with these particular constituents. Overall, the relatively simple methodology used herein could efficiently replace massive field data collection to provide a basic understanding of the fate of vinasse in the environment in order to highlight the priority points to be considered in the management of this effluent. In summary, the prompt implementation of treatment plants in distilleries, in addition to a continuous and broad compositional characterization of vinasse, is essential to guarantee its adequate reuse.

  7. Identification of potential soil water retention using hydric numerical model at arid regions by land-use changes

    Directory of Open Access Journals (Sweden)

    Mohamed Abu-hashim

    2015-12-01

    Full Text Available Assessment of soil water retention in arid region is an input required parameter in precision water management at large scale. Investigations were carried out in Tanta catchment in the middle Nile Delta, Egypt (30° 45 N, 30° 55 E, where collecting soil samples covered different hydrological soil groups and land-uses. Based on the natural resource conservation service curve number model (NRCS-CN, CN approach was used to investigate the effect of spatio-temporal variations of different land-uses on soil water retention. Potential soil water retention from 1990 to 2015 was reduced by 118.1 m3 per hectare with decreasing cropland area. Urbanization encroachment from 1990 to 2015 was increased by 2.13% by decreasing cropland with 15.3% (5300 ha in 2015. This resulted in losing the potential soil water retention by 625,968.42 m3 water for the whole catchment area. Impact of land degradation was pronounced, where 2.65%, 29.35%, and 1.11% of the initial crop land-use in 1990 were converted to bare soil, fallow, and urban area, respectively in 2015. Implementation of (S value of the NRCS-CN model with GIS technique provides useful measure to identify land-use changes of potential water storage capacity at catchment scale.

  8. Availability of potentially hazardous elements in soils and their transfer to plants. A case study in polluted soils from the Iberian Pyrite Belt (SW Spain)

    Science.gov (United States)

    Romero-Baena, Antonio; Abreu, Maria Manuela; Santos, Erika S.; Arán, Diego; González, Isabel

    2017-04-01

    Protocols for the study of potentially polluted soils by potentially hazardous elements (PHEs) are based on total element concentration. Nevertheless, the hazard depends on their availability and ability to be uptake and translocated to edible part of the plants and consequently to the food chain. Because the bioavailability of elements depends on several factors, as soil properties and plant species, there is not a universal method for its evaluation. The objectives of this work are: to assess the bioavailability of PHEs using different aqueous solutions for chemical elements extraction from different soils and to evaluate its concentrations in edible part of Lactuca sativa (lettuce) and Petroselinum crispum (parsley). The study has been carried out in four soils polluted by mining activities in Tharsis, Sotiel and Riotinto-Nerva areas (Iberian Pyrite Belt, SW Spain). The soils show high concentration in PHEs (e.g. As 471-1645, Cu 333-1455, Pb 1143-5131, Zn 273-1371 mg/kg). The pH is neutral (7.1-7.9) and the content in organic carbon ranges from 34 to 85 g/kg. For this purpose, experimental work was performed in greenhouse conditions in pots filled with 1.5 kg soil/pot (n=5 per soil). Lettuce and parsley seedlings (11 and 6 cm height, respectively) were transplanted. After six weeks of growth, plants were harvested and soil samples were collected. The availability of PHEs in soils (beginning and end of the assay) has been assessed by extraction with different aqueous solutions: water (24 hours contact); 1 mol/dm3 ammonium acetate (6 hours contact); DTPA (0.005 mol/dm3 diethylenetriaminepentaacetic acid + 0.1 mol/dm3 triethanolamine + 0.01 mol/dm3 calcium chloride; 6 hours contact); and 10 mmol/dm3 of a mixture of low-molecular weight organic acids (acetic, lactic, citric, malic, formic acids; molar ratio 4:2:1:1:1; 16 hours contact; rhizosphere-based method). The availability of As has been assessed by extraction with 0.05 mol/dm3 ammonium monophosphate (16 hours

  9. Black Carbon (Biochar) In Water/Soil Environments: Molecular Structure, Sorption, Stability, and Potential Risk.

    Science.gov (United States)

    Lian, Fei; Xing, Baoshan

    2017-12-05

    Black carbon (BC) is ubiquitous in the environments and participates in various biogeochemical processes. Both positive and negative effects of BC (especially biochar) on the ecosystem have been identified, which are mainly derived from its diverse physicochemical properties. Nevertheless, few studies systematically examined the linkage between the evolution of BC molecular structure with the resulted BC properties, environmental functions as well as potential risk, which is critical for understanding the BC environmental behavior and utilization as a multifunctional product. Thus, this review highlights the molecular structure evolution of BC during pyrolysis and the impact of BC physicochemical properties on its sorption behavior, stability, and potential risk in terrestrial and aqueous ecosystems. Given the wide application of BC and its important role in biogeochemical processes, future research should focus on the following: (1) establishing methodology to more precisely predict and design BC properties on the basis of pyrolysis and phase transformation of biomass; (2) developing an assessment system to evaluate the long-term effect of BC on stabilization and bioavailability of contaminants, agrochemicals, and nutrient elements in soils; and (3) elucidating the interaction mechanisms of BC with plant roots, microorganisms, and soil components.

  10. Study on the distribution of organic carbon in soil fractions and its reaction potential of binding the pesticides

    Science.gov (United States)

    Chowdhury, Ashim

    2010-05-01

    STUDY ON THE DISTRIBUTION OF ORGANIC CARBON IN SOIL FRACTIONS AND ITS REACTION POTENTIAL OF BINDING THE PESTICIDES **SUMITRA ROY1, SANKHAJIT ROY1, *ASHIM CHOWDHURY2, SASWATI PRADHAN2 and PETER BURAUEL3 1Department of Agricultural Chemicals, Bidhan Chandra Krishi Viswavidyalay, Mohanpur, West Bengal, India. 2Department of Agricultural Chemistry and Soil Science, University of Calcutta, West Bengal, India. 3Institute of Chemical Dynamics & Geosphere, FZ-Juelich, Germany. *Correspondence: ashimkly@hotmail.com **Research work carried out as DAAD Sandwich research fellow at FZ- Juelich, Germany Soil is the ultimate sink of all selectively applied pesticides. In addition to the basic physicochemical data of an active ingredient, the fate of the various compounds is largely determined by the type of application. Finally, pesticide and their metabolites, as well as structural elements, remain in the native carbon reserves of the soil or are sorbed & fixed to clay minerals and clay- humus complexes. Soil organic matter (SOM) and the soil microbial community are the crucial components which regulate soil processes and contribute towards the stability of the soil ecosystem. It is an energy source for biological mineralization processes, functions as a buffer and participates in chemical reaction. Knowledge is essential to understand the extent to which the SOM influences the mobilization and immobilization processes of foreign substance in soil and the substance transport and pollutant decomposition in soil. The freshly incorporated organic matter undergoes mineralization and the non mineralized carbon fraction is of special relevance with respect to soil stability in general and decisive for the fate and particular the persistence of xenobiotics in soil. The biological and physicochemical interactions establishing equilibrium between the organic matter bound, fixed or complexed to the soil matrix and that dissolve in the soil solution must be understood in detail to realize

  11. Potential feedbacks between snow cover, soil moisture and surface energy fluxes in Southern Norway

    Science.gov (United States)

    Brox Nilsen, Irene; Tallaksen, Lena M.; Stordal, Frode

    2017-04-01

    At high latitudes, the snow season has become shorter during the past decades because snowmelt is highly sensitive to a warmer climate. Snowmelt influences the energy balance by changing the albedo and the partitioning between latent and sensible heat fluxes. It further influences the water balance by changing the runoff and soil moisture. In a previous study, we identified southern Norway as a region where significant temperature changes in summer could potentially be explained by land-atmosphere interactions. In this study we hypothesise that changes in snow cover would influence the summer surface fluxes in the succeeding weeks or months. The exceptionally warm summer of 2014 was chosen as a test bed. In Norway, evapotranspiration is not soil moisture limited, but energy limited, under normal conditions. During warm summers, however, such as in 2014, evapotranspiration can be restricted by the available soil moisture. Using the Weather Research and Forecasting (WRF) model we replace the initial ground conditions for 2014 with conditions representative of a snow-poor spring and a snow-rich spring. WRF was coupled to Noah-MP at 3 km horizontal resolution in the inner domain, and the simulations covered mid-May through September 2014. Boundary conditions used to force WRF were taken from the Era-Interim reanalysis. Snow, runoff, soil moisture and soil temperature observational data were provided by the Norwegian Water Resources and Energy Directorate for validation. The validation shows generally good agreement with observations. Preliminary results show that the reduced snowpack, hereafter "sim1" increased the air temperature by up to 5 K and the surface temperature by up to 10 K in areas affected by snow changes. The increased snowpack, hereafter "sim2", decreased the air and surface temperature by the same amount. These are weekly mean values for the first eight simulation weeks from mid May. Because of the higher net energy available ( 100 Wm-2) in sim 1, both

  12. Monitoring Soil Sealing in Guadarrama River Basin, Spain, and Its Potential Impact in Agricultural Areas

    Directory of Open Access Journals (Sweden)

    Eugenia Pérez

    2016-01-01

    Full Text Available This study analyzes soil sealing and its repercussions in the loss of fertile soils, which are more appropriate for agriculture use. Also, soil sealing increases flood risk. The main objective is to estimate soil loss by sealing in the Guadarrama River Basin (Madrid, Spain between 1961 and 2011. The combination of digital processing (Normalized Difference Vegetation Index (NDVI, principal components and convolution filters of satellite imagery with the digital terrain model helps to detect risk areas and allows quick updating of sealed soil mapping. The supervised classifications of the images were used to estimate the actual soil loss by sealing (9% in 2011 in the Guadarrama River Basin and the types and agrologic classes that have been lost. Soil loss occurs to a greater extent in highly permeable soils (sands and in the most fertile soils. The main sealed soil associations are luvisols (alfisols, regosols (entisols and cambisols (inceptisols.

  13. Simultaneous Voltammetric/Amperometric Determination of Sulfide and Nitrite in Water at BDD Electrode

    Directory of Open Access Journals (Sweden)

    Anamaria Baciu

    2015-06-01

    Full Text Available This work reported new voltammetric/amperometric-based protocols using a commercial boron-doped diamond (BDD electrode for simple and fast simultaneous detection of sulfide and nitrite from water. Square-wave voltammetry operated under the optimized working conditions of 0.01 V step potential, 0.5 V modulation amplitude and 10 Hz frequency allowed achieving the best electroanalytical parameters for the simultaneous detection of nitrite and sulfide. For practical in-field detection applications, the multiple-pulsed amperometry technique was operated under optimized conditions, i.e., −0.5 V/SCE for a duration of 0.3 s as conditioning step, +0.85 V/SCE for a duration of 3 s that assure the sulfide oxidation and +1.25 V/SCE for a duration of 0.3 s, where the nitrite oxidation occurred, which allowed the simultaneously detection of sulfide and nitrite without interference between them. Good accuracy was found for this protocol in comparison with standardized methods for each anion. Also, no interference effect was found for the cation and anion species, which are common in the water matrix.

  14. Assessing the Soil Physiological Potential Using Pedo-Biological Diagnosis Under Minimum-Tillage System and Mineral Fertilization

    Directory of Open Access Journals (Sweden)

    Lazar Bireescu

    2014-11-01

    Full Text Available The main objective of sustainable agriculture is the protection of environment and natural vegetal and soil resources. Accordingly, the objective of this research was to assess the impact of technological systems by minimum tillage on soil biological activity, using the Pedo-Biological Diagnosis of Soil Resources. Our research was conducted on haplic chernozem from Experimental Station of UASVM of Iasi, Romania, during the seasonal dynamic, to the soybean crop, on unfertilized and fertilized agrofond, using moderate mineral doses (N80P80 as average of 2009–2010 period, under minimum tillage (2x disk, paraplow, chisel compared to conventional (plugging at 20 cm and 30 cm. In the case of soil works with chisel and paraplow without return of furrow, the Pedo-Biological Diagnosis highlights an increase of soil physiological potential, in the both variants (unfertilized and fertilized, unlike the method of alternating the depth of plugging that proved to be ineffective.

  15. Effect of chemical amendments on remediation of potentially toxic trace elements (PTEs) and soil quality improvement in paddy fields.

    Science.gov (United States)

    Kim, Sung Chul; Hong, Young Kyu; Oh, Se Jin; Oh, Seung Min; Lee, Sang Phil; Kim, Do Hyung; Yang, Jae E

    2017-04-01

    Remediation of potentially toxic trace elements (PTEs) in paddy fields is fundamental for crop safety. In situ application of chemical amendments has been widely adapted because of its cost-effectiveness and environmental safety. The main purpose of this research was to (1) evaluate the reduction in dissolved concentrations of cadmium (Cd) and arsenic (As) with the application of chemical amendments and (2) monitor microbial activity in the soil to determine the remediation efficiency. Three different chemical amendments, lime stone, steel slag, and acid mine drainage sludge, were applied to paddy fields, and rice (Oryza sativa L. Milyang 23) was cultivated. The application of chemical amendments immobilized both Cd and As in soil. Between the two PTEs, As reduction was significant (p PTEs in soil is dependent on soil pH and reduces PTE toxicity. Overall, the application of chemical amendments could be utilized for decreasing PTE (As and Cd) bioavailability and increasing microbial activity in the soil.

  16. Avoidance, biomass and survival response of soil dwelling (endogeic) earthworms to OECD artificial soil: potential implications for earthworm ecotoxicology.

    Science.gov (United States)

    Brami, C; Glover, A R; Butt, K R; Lowe, C N

    2017-05-01

    Soil dwelling earthworms are now adopted more widely in ecotoxicology, so it is vital to establish if standardised test parameters remain applicable. The main aim of this study was to determine the influence of OECD artificial soil on selected soil-dwelling, endogeic earthworm species. In an initial experiment, biomass change in mature Allolobophora chlorotica was recorded in Standard OECD Artificial Soil (AS) and also in Kettering Loam (KL). In a second experiment, avoidance behaviour was recorded in a linear gradient with varying proportions of AS and KL (100% AS, 75% AS + 25% KL, 50% KS + 50% KL, 25% AS + 75% KL, 100% KL) with either A. chlorotica or Octolasion cyaneum. Results showed a significant decrease in A. chlorotica biomass in AS relative to KL, and in the linear gradient, both earthworm species preferentially occupied sections containing higher proportions of KL over AS. Soil texture and specifically % composition and particle size of sand are proposed as key factors that influenced observed results. This research suggests that more suitable substrates are required for ecotoxicology tests with soil dwelling earthworms.

  17. Electrocatalytic reduction of nitrite on tetraruthenated metalloporphyrins/Nafion glassy carbon modified electrode

    Energy Technology Data Exchange (ETDEWEB)

    Calfuman, Karla [Facultad de Ciencias, Departamento de Quimica, Universidad de Chile, Las Palmeras 3425, Casilla 653, Nunoa, Santiago (Chile); Aguirre, Maria Jesus [Facultad de Quimica y Biologia, Departamento de Quimica de los Materiales, Universidad de Santiago de Chile, Santiago (Chile); Canete-Rosales, Paulina; Bollo, Soledad [Facultad de Ciencias Quimicas y Farmaceuticas, Departamento de Quimica Farmacologica y Toxicologica, Universidad de Chile, Santiago (Chile); Llusar, Rosa [Departamento de Quimica Fisica y Analitica, Universidad de Jaume I, Castellon (Spain); Isaacs, Mauricio, E-mail: misaacs@uchile.cl [Facultad de Ciencias, Departamento de Quimica, Universidad de Chile, Las Palmeras 3425, Casilla 653, Nunoa, Santiago (Chile)

    2011-10-01

    Highlights: > Preparation and characterization of modified electrodes with M(II) Tetraruthenated porphyrins onto a Nafion film. > The electrodes were characterized by SEM, TEM, AFM and SECM techniques. > The modified electrodes are active in the electrochemical reduction of nitrite at -660 mV vs Ag/AgCl. > GC/Nf/CoTRP modified electrode is more electrochemically active than their Ni and Zn analogues. - Abstract: This paper describes the electrochemical reduction of nitrite ion in neutral aqueous solution mediated by tetraruthenated metalloporphyrins (Co(II), Ni(II) and Zn(II)) electrostatically assembled onto a Nafion film previously adsorbed on glassy carbon or ITO electrodes. Scanning electron microscope (SEM-EDX) and transmission electron microscopy (TEM) results have shown that on ITO electrodes the macrocycles forms multiple layers with a disordered stacking orientation over the Nafion film occupying hydrophobic and hydrophilic sites in the polyelectrolyte. Atomic force microscopy (AFM) results demonstrated that the Nafion film is 35 nm thick and tetraruthenated metalloporphyrins layers 190 nm thick presenting a thin but compacted morphology. Scanning electrochemical microscopy (SECM) images shows that the Co(II) tetraruthenated porphyrins/Nf/GC modified electrode is more electrochemically active than their Ni and Zn analogues. These modified electrodes are able to reduce nitrite at -660 mV showing enhanced reduction current and a decrease in the required overpotential compared to bare glassy carbon electrode. Controlled potential electrolysis experiments verify the production of ammonia, hydrazine and hydroxylamine at potentials where reduction of solvent is plausible demonstrating some selectivity toward the nitrite ion. Rotating disc electrode voltammetry shows that the factor that governs the kinetics of nitrite reduction is the charge propagation in the film.

  18. Combined exposure to ambient UVB radiation and nitrite negatively affects survival of amphibian early life stages

    Energy Technology Data Exchange (ETDEWEB)

    Macias, Guadalupe [Donana Biological Station, CSIC, Spanish Council for Scientific Research. P.O. Box 1056, Sevilla 41013 (Spain); Marco, Adolfo [Donana Biological Station, CSIC, Spanish Council for Scientific Research. P.O. Box 1056, Sevilla 41013 (Spain)], E-mail: amarco@ebd.csic.es; Blaustein, Andrew R. [Department of Zoology, Oregon State University, Corvallis, Oregon, 97331 (United States)

    2007-10-15

    Many aquatic species are sensitive to ambient levels of ultraviolet-B radiation (UVB) and chemical fertilizers. However, recent studies indicate that the interaction among multiple stressors acting simultaneously could be contributing to the population declines of some animal species. Therefore, we tested the potential synergistic effects between ambient levels of UVB and a contaminant, sodium nitrite in the larvae of two amphibian species, the common European toad Bufo bufo and the Iberian green frog Rana perezi. We studied R. perezi from both mountain and coastal populations to examine if populations of the same species varied in their response to stressors in different habitats. Both species were sensitive to the two stressors acting alone, but the interaction between the two stressors caused a multiplicative impact on tadpole survival. For B. bufo, the combination of UVB and nitrite was up to seven times more lethal than mortality for each stressor alone. In a coastal wetland, the combination of UVB and nitrite was four times more toxic for R. perezi than the sum of the effect on mortality for each stressor alone. One mg/L of nitrite killed half the population of R. perezi at Gredos Mountains at day 10 in the absence of UVB. In the presence of UVB, 50% of the tadpoles from the same experiment died at day 7. Similar toxic response were found for R. perezi in two highly contrasted environments suggesting this synergistic interaction can be a widespread phenomenon. The interaction of excess chemical fertilizers and manure with ambient UVB radiation could be contributing to the global decline of some amphibian species. We suggest that potential exposure to UVB radiation be accounted for when assessing water quality criteria regarding nitrite pollution.

  19. Combined exposure to ambient UVB radiation and nitrite negatively affects survival of amphibian early life stages.

    Science.gov (United States)

    Macías, Guadalupe; Marco, Adolfo; Blaustein, Andrew R

    2007-10-15

    Many aquatic species are sensitive to ambient levels of ultraviolet-B radiation (UVB) and chemical fertilizers. However, recent studies indicate that the interaction among multiple stressors acting simultaneously could be contributing to the population declines of some animal species. Therefore, we tested the potential synergistic effects between ambient levels of UVB and a contaminant, sodium nitrite in the larvae of two amphibian species, the common European toad Bufo bufo and the Iberian green frog Rana perezi. We studied R. perezi from both mountain and coastal populations to examine if populations of the same species varied in their response to stressors in different habitats. Both species were sensitive to the two stressors acting alone, but the interaction between the two stressors caused a multiplicative impact on tadpole survival. For B. bufo, the combination of UVB and nitrite was up to seven times more lethal than mortality for each stressor alone. In a coastal wetland, the combination of UVB and nitrite was four times more toxic for R. perezi than the sum of the effect on mortality for each stressor alone. One mg/L of nitrite killed half the population of R. perezi at Gredos Mountains at day 10 in the absence of UVB. In the presence of UVB, 50% of the tadpoles from the same experiment died at day 7. Similar toxic response were found for R. perezi in two highly contrasted environments suggesting this synergistic interaction can be a widespread phenomenon. The interaction of excess chemical fertilizers and manure with ambient UVB radiation could be contributing to the global decline of some amphibian species. We suggest that potential exposure to UVB radiation be accounted for when assessing water quality criteria regarding nitrite pollution.

  20. Landscape Influences on Potential Soil Respiration Rates in a Forested Watershed of Southeastern Kentucky

    Science.gov (United States)

    Amanda C. Abnee; James A. Thompson; Randall K. Kolka; Elisa M. D' Angelo; Mark S. Coyne

    2004-01-01

    Soil respiration measurements conducted in the laboratory have been shown to be related to temperature and moisture, with maximum rates at soil temperatures between 25 and 40°C and soil moisture between -0.01 and -0.10 MPa. A preliminary study using forest soils from eastern Kentucky supported the previous research with soil respiration rates greater at 25°C than at 15...

  1. Organochlorine pesticides in surface soils from obsolete pesticide dumping ground in Hyderabad City, Pakistan: contamination levels and their potential for air-soil exchange.

    Science.gov (United States)

    Alamdar, Ambreen; Syed, Jabir Hussain; Malik, Riffat Naseem; Katsoyiannis, Athanasios; Liu, Junwen; Li, Jun; Zhang, Gan; Jones, Kevin C

    2014-02-01

    This study was conducted to examine organochlorine pesticides (OCPs) contamination levels in the surface soil and air samples together with air-soil exchange fluxes at an obsolete pesticide dumping ground and the associated areas from Hyderabad City, Pakistan. Among all the sampling sites, concentrations of OCPs in the soil and air samples were found highest in obsolete pesticide dumping ground, whereas dominant contaminants were dichlorodiphenyltrichloroethane (DDTs) (soil: 77-212,200 ng g(-1); air: 90,700 pg m(-3)) and hexachlorocyclohexane (HCHs) (soil: 43-4,090 ng g(-1); air: 97,400 pg m(-3)) followed by chlordane, heptachlor and hexachlorobenzene (HCB). OCPs diagnostic indicative ratios reflect historical use as well as fresh input in the study area. Moreover, the air and soil fugacity ratios (0.9-1.0) at the dumping ground reflecting a tendency towards net volatilization of OCPs, while at the other sampling sites, the fugacity ratios indicate in some cases deposition and in other cases volatilization. Elevated concentrations of DDTs and HCHs at pesticide dumping ground and its surroundings pose potential exposure risk to biological organisms, to the safety of agricultural products and to the human health. Our study thus emphasizes the need of spatio-temporal monitoring of OCPs at local and regional scale to assess and remediate the future adverse implications. © 2013.

  2. Rhizospheric soil enzyme activities and phytominimg potential of Aeluropus lagopoides and Cyperus conglomeratus growing in contaminated soils at the banks of artificial lake of reclaimed wastewater.

    Science.gov (United States)

    Abbas, Zahid Khorshid

    2017-11-02

    This work investigates the phytoremediation potential of Aeluropus lagopoides and Cyperus conglomeratus, growing indigenously in the vicinity of an artificial lake of reclaimed water in Tabuk, Saudi Arabia . The sampling sites were located at different distances from the wastewater treatment plants. Trace metal contents were higher in roots than shoots in both these plants. Soil urease activity in rhizophere increased linearly along the sampling sites, however, soil alkaline phosphatase and β-glucosidase activities were higher at site 2 but at site 3, the activities of both these soil enzymes reduced. Significant correlations were observed between soil urease activity and the bioconcentration factor (BCF) of Cd, Cu, Pb, and As in A. lagopoides and translocation factor (TF) for all metals in both these plants. Soil β-glucosidase activity was negatively correlated with the TF of Cd, Cu, Pb, and As in A. lagopoides and positively in C. conglomeratus, respectively. Higher BCF of Cd, Cu and Pb than C. conglomeratus and suitable for phytostabilization, however at site 3, C. conglomeratus showed better phytostabilization efficiency for As, as the BCF of As was higher than the A. lagopoides. On the basis of metal accumulation efficiency and rhizospheric soil urease and β-glucosidase activities, A. lagopoides species proved to be a better option for application in phytostabilization strategy than C. conglomeratus plants in the area surrounding the artificial lake of reclaimed water in Tabuk, Saudi Arabia.

  3. Using saliva nitrite and nitrate levels as a biomarker for drug induced gingival overgrowth

    Directory of Open Access Journals (Sweden)

    Erkan eSukuroglu

    2015-12-01

    Full Text Available Aim: Drug-induced gingival overgrowth has a multifactorial nature and the pathogenesis is still uncertain. It has been suggested that Nitric Oxide (NO might play a role in the pathogenesis of drug-induced gingival overgrowth due to the contribution of NO to immune response and matrix degradation. NO levels in biological fluids have been used as a diagnostic biomarker in many diseases. The aim of this study is to determine whether NO levels in plasma, saliva and gingival crevicular fluid (GCF can serve as a potential biomarker for the evaluation of drug-induced gingival overgrowth risk. Material and Methods: A total of 104 patients, receiving cyclosporine A (n=35, phenytoin (n=25, nifedipine (n=26 or diltiazem (n=18 participated in the study. The amount of gingival overgrowth was evaluated with two indices and was given as percentage. Periodontal clinical parameters including plaque index (PI, gingival index (GI, gingival bleeding time index (GBTI and probing depth (PD were also assessed. Saliva, GCF and plasma samples were obtained from each participants. Nitrite and nitrate levels in saliva, GCF and plasma were analyzed by Griess reagent. Results: Salivary nitrite and nitrate levels in responders were significantly higher than those in non-responders in only phenytoin group (p˂0.05. Nitrite and nitrate levels of gingival crevicular fluid and plasma did not significantly differ between responders and non-responders in all study groups (p˃0.05. Salivary nitrite levels exhibited a significant correlation with PD, GBTI, severity of gingival overgrowth (%GO and GCF volume (p˂0.05. Additionally, a strong positive correlation was detected between saliva and plasma nitrate levels (p˂0.005. However, both nitrite and nitrate levels in GCF and plasma demonstrated no significant correlation with clinical parameters, GO severity and GCF volume (p˃0.05.Conclusion: Salivary nitrite and nitrate levels could be used as periodontal disease biomarkers in

  4. Potentially toxic element contamination in soil and accumulation in maize plants in a smelter area in Kosovo.

    Science.gov (United States)

    Nannoni, Francesco; Rossi, Sara; Protano, Giuseppe

    2016-06-01

    A biogeochemical field study was carried out in the industrial area of Kosovska Mitrovica in northern Kosovo, where agricultural soils were contaminated by potentially toxic elements due to smelting activity. Total and bioavailable contents of As, Cd, Co, Cu, Pb, Sb, U and Zn in soil and their concentrations in maize roots and grains were determined. Soil contamination by As, Cd, Cu, Pb, Sb and Zn was variable from slightly to highly contaminated soils and influenced both the bioavailable fraction and accumulation of these potentially toxic elements in maize tissues. The comparison between potentially toxic element concentrations in roots and grains indicated that maize is able to limit the transfer of non-essential elements to edible parts. The plant-to-soil bioconcentration indices suggested that the transfer of potentially toxic elements from soil to plant was predicted better by bioavailable concentrations than by the total contents. These indices further identified some competitions and interactions among these elements in root uptake and root-to-grain translocation.

  5. A comparative study of nitrite reduction by synthetic and biogenic Fe(II-III) hydroxysalts green rusts: Evidence for hydroxyl-nitrite green rust formation as an intermediate reaction product.

    Science.gov (United States)

    Ona-Nguema, G.; Guerbois, D.; Morin, G.; Zhang, Y.; Noel, V.; Brest, J.

    2013-12-01

    The occurrence of high nitrite concentrations as a result of anthropogenic activities is an important water quality concern as it is highly toxic to human and fauna, and it is used as a nitrogen source for the assimilation process. The toxicity of nitrite is related to its transformation into carcinogenic N-nitroso compounds, which are suspected to be responsible for some gastric cancers, and to its ability to convert the hemoglobin to methaemoglobin what is then unable to fix oxygen and to transport it to the tissues, involving hypoxia and the blue-baby syndrome [1]. To reduce the adverse effect of nitrite on human health and on macroalgal blooms, any process enhancing the transformation of nitrite ions to nitrogen gas is of interest for the remediation of natural environments. To achieve this purpose the use of processes involving Fe(II)-containing minerals could be considered as one of the best options. Green-rusts are mixed Fe(II-III) layered double hydroxides commonly found in anoxic zones of natural environments such as sediments and hydromorphic soils. In such anoxic environments, green rust minerals play an important role in the biogeochemical redox cycling of iron and nitrogen, and can affect the speciation and mobility of many organic and inorganic contaminants. The present study investigates the reduction of nitrite by two synthetic and two biogenic green rusts. On the one hand, Fe(II-III) hydroxychloride and Fe(II-III) hydroxycarbonate green rusts were used as synthetic interlayer forms of GR, which are referred to as ';syn-GR(CO3)' and ';syn-GR(Cl)', respectively. On the other hand, the study was performed with biogenic Fe(II-III) hydroxycarbonate green rusts obtained from the bioreduction of two ferric precursors, either Fe(III)-oxyhydroxycarbonate or lepidocrocite; these biogenic green rusts are referred to as ';bio-GR(CO3)F' and ';bio-GR(CO3)L', respectively. For synthetic green rusts, results showed that the oxidation of both syn-GR(CO3) and syn

  6. Metribuzin transport in undisturbed soil cores under controlled water potential conditions: experiments and modelling to evaluate the risk of leaching in a sandy loam soil profile.

    Science.gov (United States)

    Pot, Valérie; Benoit, Pierre; Le Menn, Mona; Eklo, Ole-Martin; Sveistrup, Tore; Kvaerner, Jens

    2011-04-01

    Mobility of pesticides in soils is often evaluated and characterised in the surface soil layers rather than at different depths where soil characteristics such as soil organic matter, microbial biomass or clay contents can strongly change pesticide behaviour. The objective of this work was to characterise the reactivity of the herbicide metribuzin in three main soil horizons found in the 0-80 cm profile of an alluvial soil of southern Norway under dynamic transport conditions. A laboratory infiltrometer was used to perform percolation experiments in soil cores sampled in the three horizons Ap, Bw and Bw/C, at a fixed matric potential of -10 cm, thus preventing pores of equivalent radii higher than 0.015 cm from contributing to water flow. The physical equilibrium transport model correctly described the transport of water tracer (bromide). The distribution coefficient K(d) values were estimated to be 0.29, 0.17 ± 0.02 and 0.15 ± 0.00 L kg(-1) for horizons Ap, Bw and Bw/C respectively, in close agreement with batch sorption data. Degradation was found only for the surface horizon with a short half-life of about 5 days, in disagreement with longer half-lives found in batch and field degradation data. For all horizons, a kinetic sorption model was needed for better description of metribuzin leaching. Chemical non-equilibrium was greatest in the Bw horizon and lowest in the Bw/C horizon. Overall, metribuzin exhibited a greater mobility in the deeper horizons. The risk of metribuzin transfer to groundwater in such alluvial soils should therefore be considered. Copyright © 2011 Society of Chemical Industry.

  7. Soil salinity and matric potential interaction on water use, water use efficiency and yield response factor of bean and wheat.

    Science.gov (United States)

    Khataar, Mahnaz; Mohhamadi, Mohammad Hossien; Shabani, Farzin

    2018-02-08

    We studied the effects of soil matric potential and salinity on the water use (WU), water use efficiency (WUE) and yield response factor (Ky), for wheat (Triticum aestivum cv. Mahdavi) and bean (Phaseoulus vulgaris cv. COS16) in sandy loam and clay loam soils under greenhouse conditions. Results showed that aeration porosity is the predominant factor controlling WU, WUE, Ky and shoot biomass (Bs) at high soil water potentials. As matric potential was decreased, soil aeration improved, with Bs, WU and Ky reaching maximum value at -6 to -10 kPa, under all salinities. Wheat WUE remained almost unchanged by reduction of matric potential under low salinities (EC ≤ 8 dSm-1), but increased under higher salinities (EC ≥ 8 dSm-1), as did bean WUE at all salinities, as matric potential decreased to -33 kPa. Wheat WUE exceeds that of bean in both sandy loam and clay loam soils. WUE of both plants increased with higher shoot/root ratio and a high correlation coefficient exists between them. Results showed that salinity decreases all parameters, particularly at high potentials (h = -2 kPa), and amplifies the effects of waterlogging. Further, we observed a strong relationship between transpiration (T) and root respiration (Rr) for all experiments.

  8. Modifying a known gelator scaffold for nitrite detection.

    Science.gov (United States)

    Zurcher, Danielle M; Adhia, Yash J; Romero, Julián Díaz; McNeil, Anne J

    2014-07-25

    The process of selecting and modifying a known gelator scaffold to develop a new nitrite-based sensor is described. Five new azo-sulfonate gelators were discovered and characterized. The most promising scaffold exhibits a stable diazonium intermediate, proceeds in a high yield, and gels nitrite-spiked tap, river, and pond water.

  9. Nitrite enhances liver graft protection against cold ischemia ...

    African Journals Online (AJOL)

    Amani Cherif-Sayadi

    2017-03-30

    Mar 30, 2017 ... 2 h. Control livers were perfused without cold storage. Results: Nitrite effectively protected the rat liver grafts from the onset of cold I/R injury. L-NAME treatment did not abolish the beneficial effects of nitrite. Liver damage, protein oxidation .... phosphatase (PAL) are associated with hepatocellular damage ...

  10. Nitrate and nitrite in biology, nutrition and therapeutics

    NARCIS (Netherlands)

    Lundberg, J.O.; van Faassen, E.E.H.|info:eu-repo/dai/nl/071100938; Gladwin, M.T.; Ahluwalia, A.; Benjamin, N.

    2009-01-01

    Inorganic nitrate and nitrite from endogenous or dietary sources are metabolized in vivo to nitric oxide (NO) and other bioactive nitrogen oxides. The nitrate-nitrite-NO pathway is emerging as an important mediator of blood flow regulation, cell signaling, energetics and tissue responses to hypoxia.

  11. Nitrite as regulator of hypoxic signaling in mammalian physiology

    NARCIS (Netherlands)

    van Faassen, E.E.H.|info:eu-repo/dai/nl/071100938; Bahrami, S.; Feelisch, M.; Hogg, N.; Kelm, M.

    2009-01-01

    In this review we consider the effects of endogenous and pharmacological levels of nitrite under conditions of hypoxia. In humans, the nitrite anion has long been considered as metastable intermediate in the oxidation of nitric oxide radicals to the stable metabolite nitrate. This oxidation cascade

  12. Electrochemical removal of nitrite in simulated aquaculture wastewater

    African Journals Online (AJOL)

    Electrochemical removal of nitrite at a concentration of 10 mg l-1 from synthetic aquaculture wastewater was investigated in this study using a batch reactor. The effects of important operating parameters such as electrode material and applied current density were studied. The highest nitrite removal is achieved with nickel ...

  13. Unraveling the origin of the nitrite-mediated hypoxic vasodilation

    DEFF Research Database (Denmark)

    Fago, Angela; Dalsgaard, T.; Simonsen, U.

    2007-01-01

    Circulating nitrite has recently emerged as an important physiological metabolite that contributes to increase vasodilation during tissue hypoxia. Using a wire myograph, we have investigated how the nitrite-dependent vasodilation in rat aortic rings is controlled by oxygen tension, norepinephrine...

  14. Nitrite and nitrate determinations in plasma: a critical evaluation

    NARCIS (Netherlands)

    Moshage, H.; Kok, B.; Huizenga, J. R.; Jansen, P. L.

    1995-01-01

    Plasma nitrite and nitrate determinations are increasingly being used in clinical chemistry as markers for the activity of nitric oxide synthase and the production of nitric oxide radicals. However, a systematic evaluation of the determination of nitrite and nitrate in plasma has not been performed.

  15. determination of nitrite, nitrate and total nitrogen in vegetable samples

    African Journals Online (AJOL)

    The above colour reaction system has been applied successfully for the determination of nitrite, nitrate and total nitrogen in vegetable samples. Unreduced samples give direct measure for nitrite whilst reduction of samples by copperized-cadmium column gives total nitrogen content and their difference shows nitrate content ...

  16. Amperometric Carbon Fiber Nitrite Microsensor for In Situ Biofilm Monitoring

    Science.gov (United States)

    A highly selective needle type solid state amperometric nitrite microsensor based on direct nitrite oxidation on carbon fiber was developed using a simplified fabrication method. The microsensor’s tip diameter was approximately 7 µm, providing a high spatial resolution of at lea...

  17. Occurrence and Toxicological Significance of Nitrate and Nitrite in ...

    African Journals Online (AJOL)

    Aim: To determine and evaluate the levels of nitrate and nitrite in some commercial infant formula in view of the health implications of these factors. Method: Nitrate and nitrite, which may create significant health problems in infants, were determined in four commercial infant formula. The public health and toxicological ...

  18. A field screening test for the assessment of concentrations and mobility of potentially toxic elements in soils: a case study on urban soils from Rome and Novi Sad.

    Science.gov (United States)

    Montereali, Maria Rita; Pinto, Valentina; Schiavella, Francesca; Armiento, Giovanna; Angelone, Massimo; Crovato, Cinzia; Manojlović, Maja; Čabilovski, Ranko; Cremisini, Carlo

    2017-08-23

    The increasing demand for environmental pollution control results in the development and use of new procedures for the determination of dangerous chemicals. Simple screening methods, which can be used directly in the field for a preliminary assessment of soil contamination, seem to be extremely advantageous. In our laboratory, we developed and optimized a rapid test for a preliminary evaluation of both the concentration and the mobility of some potentially toxic metals in soils. This screening test consists of a single extraction of the soil sample with a buffer solution, followed by the titration of the extracted solution with dithizone to determine the contents of bi-valent heavy metals (such as Pb, Cu, Zn, and Cd). This screening method was then directly applied in the field during the sampling campaign in the framework of an Italian-Serbian collaborative project, finalized in the study of metal availability in soils. The results obtained in the field with the rapid test were compared with those obtained in the laboratory following the conventional procedure commonly used to evaluate metal bioavailability (diethylenetriaminepentaacetic extraction). Moreover, selected samples were analyzed sequentially in the laboratory using the standardized BCR three-step sequential extraction procedure. The screening test gave results conceptually in good agreement with those obtained via the BCR procedure. These preliminary data show that the proposed screening test is a reliable method for the preliminary rapid evaluation of metal total concentrations and of potential metal mobility in soils, supporting sampling activities directly in the field.

  19. Soil Water Potential Control of the Relationship between Moisture and Greenhouse Gas Fluxes in Corn-Soybean Field

    Directory of Open Access Journals (Sweden)

    Dinesh Panday

    2015-08-01

    Full Text Available Soil water potential (Ψ controls the dynamics of water in soils and can therefore affect greenhouse gas fluxes. We examined the relationship between soil moisture content (θ at five different levels of water potential (Ψ = 0, −0.05, −0.1, −0.33 and −15 bar and greenhouse gas (carbon dioxide, CO2; nitrous oxide, N2O and methane, CH4 fluxes. The study was conducted in 2011 in a silt loam soil at Freeman farm of Lincoln University. Soil samples were collected at two depths: 0–10 and 10–20 cm and their bulk densities were measured. Samples were later saturated then brought into a pressure plate for measurements of Ψ and θ. Soil air samples for greenhouse gas flux analyses were collected using static and vented chambers, 30 cm in height and 20 cm in diameter. Determination of CO2, CH4 and N2O concentrations from soil air samples were done using a Shimadzu Gas Chromatograph (GC-14. Results showed that there were significant correlations between greenhouse gas fluxes and θ held at various Ψ in the 0–10 cm depth of soil group. For instance, θ at Ψ = 0 positively correlated with measured CO2 (p = 0.0043, r = 0.49, N2O (p = 0.0020, r = 0.64 and negatively correlated with CH4 (p = 0.0125, r = −0.44 fluxes. Regression analysis showed that 24%, 41% and 19% of changes in CO2, N2O and CH4 fluxes, respectively, were due to θ at Ψ = 0 (p < 0.05. This study stresses the need to monitor soil water potential when monitoring greenhouse gas fluxes.

  20. Study of the influence of the saline solution NaCl on the potential collapse of soil

    Directory of Open Access Journals (Sweden)

    Abbeche Khelifa

    2016-01-01

    Full Text Available Collapsible soils are unsaturated soils which present a potential for large strains and a complete change to the whole particle structure after wetting with or without loading. These soils are characterized with loose structures composed of silt to fine-sand-size particles.The objective of this experimental study is to illustrate that the resistance of collapsible soil can be improved. This study demonstrates that it is possible to minimize the collapsible potential Cp to an acceptable level after chemical treatment with salt (sodium chloride NaCl at different concentrations (0.5, 1.0, 1.5 and 2.0 mole/liter and at different compaction energies. The method used in this study is based on oedometric tests with variable normal stresses.

  1. Elevated CO2 shifts the functional structure and metabolic potentials of soil microbial communities in a C4 agroecosystem

    Science.gov (United States)

    Xiong, Jinbo; He, Zhili; Shi, Shengjing; Kent, Angela; Deng, Ye; Wu, Liyou; van Nostrand, Joy D.; Zhou, Jizhong

    2015-03-01

    Atmospheric CO2 concentration is continuously increasing, and previous studies have shown that elevated CO2 (eCO2) significantly impacts C3 plants and their soil microbial communities. However, little is known about effects of eCO2 on the compositional and functional structure, and metabolic potential of soil microbial communities under C4 plants. Here we showed that a C4 maize agroecosystem exposed to eCO2 for eight years shifted the functional and phylogenetic structure of soil microbial communities at both soil depths (0-5 cm and 5-15 cm) using EcoPlate and functional gene array (GeoChip 3.0) analyses. The abundances of key genes involved in carbon (C), nitrogen (N) and phosphorus (P) cycling were significantly stimulated under eCO2 at both soil depths, although some differences in carbon utilization patterns were observed between the two soil depths. Consistently, CO2 was found to be the dominant factor explaining 11.9% of the structural variation of functional genes, while depth and the interaction of depth and CO2 explained 5.2% and 3.8%, respectively. This study implies that eCO2 has profound effects on the functional structure and metabolic potential/activity of soil microbial communities associated with C4 plants, possibly leading to changes in ecosystem functioning and feedbacks to global change in C4 agroecosystems.

  2. Long-term use of biosolids as organic fertilizers in agricultural soils: potentially toxic elements occurrence and mobility.

    Science.gov (United States)

    Marguí, E; Iglesias, M; Camps, F; Sala, L; Hidalgo, M

    2016-03-01

    The presence of potentially toxic elements (PTEs) may hinder a more widespread application of biosolids in agriculture. At present, the European Directive 86/278/CEE limit the total concentrations of seven metals (Cu, Cr, Ni, Pb, Zn, Cd and Hg) in agricultural soils and in sewage sludges used as fertilizers but it has not taken into consideration the potential impacts of other emerging micropollutants that may be present in the biosolids as well as their mobility. The aim of this study was to evaluate the accumulation and mobility of 13 elements (including regulated metals and other inorganic species) in agricultural soils repeatedly amended with biosolids for 15 years. Firstly, three digestions programs using different acid mixtures were tested to evaluate the most accurate and efficient method for analysis of soil and sludge. Results demonstrated that sewage sludge application increased concentrations of Pb and Hg in soil, but values did not exceed the quality standard established by legislation. In addition, other elements (As, Co, Sb, Ag, Se and Mn) that at present are not regulated by the Spanish and European directives were identified in the sewage sludge, and significant differences were found between Ag content in soils amended with biosolids in comparison with control soils. This fact can be related to the increasing use of silver nanoparticles in consumer products due to their antibacterial properties. Results from the leaching tests show up that, in general, the mobility degree for both regulated and non-regulated elements in soils amended with biosolids was quite low (<10 %).

  3. Potential enhancement of degradation of the nematicides aldicarb, oxamyl and fosthiazate in UK agricultural soils through repeated applications.

    Science.gov (United States)

    Osborn, Rachel K; Edwards, Simon G; Wilcox, Andrew; Haydock, Patrick P J

    2010-03-01

    The potential for enhanced degradation of the carbamoyloxime nematicides aldicarb and oxamyl and the organophosphate fosthiazate was investigated in 35 UK agricultural soils. Under laboratory conditions, soil samples received three successive applications of nematicide at 25 day intervals. The second and third applications of aldicarb were degraded at a faster rate than the first application in six of the 15 aldicarb-treated soils, and a further three soils demonstrated rapid degradation of all three applications. High organic matter content and low pH had an inhibitory effect on the rate of aldicarb degradation. Rapid degradation was observed in nine out of the ten soils treated with oxamyl. In contrast, none of the fosthiazate-treated soils demonstrated enhanced degradation. The potential for enhanced degradation of aldicarb and oxamyl was demonstrated in nine out of 15 and nine out of ten soils respectively that had previously been treated with these active substances. Degradation of fosthiazate occurred at a much slower rate, with no evidence of enhanced degradation. Fosthiazate may provide a useful alternative in cases where the efficacy of aldicarb and oxamyl has been reduced as a result of enhanced degradation.

  4. Phytoremediation potential of wild plants growing on soil contaminated with heavy metals.

    Science.gov (United States)

    Čudić, Vladica; Stojiljković, Dragoslava; Jovović, Aleksandar

    2016-09-01

    Phytoremediation is an emerging technology that employs higher plants to cleanup contaminated environments, including metal-polluted soils. Because it produces a biomass rich in extracted toxic metals, further treatment of this biomass is necessary. The aim of our study was to assess the five-year potential of the following native wild plants to produce biomass and remove heavy metals from a polluted site: poplar (Populus ssp.), ailanthus (Ailanthus glandulosa L.), false acacia (Robinia pseudoacacia L.), ragweed (Artemisia artemisiifolia L.), and mullein (Verbascum thapsus L). Average soil contamination with Pb, Cd, Zn, Cu, Ni, Cr, and As in the root zone was 22,948.6 mg kg-1, 865.4 mg kg-1, 85,301.7 mg kg-1, 3,193.3 mg kg-1, 50.7 mg kg-1, 41.7 mg kg-1,and 617.9 mg kg-1, respectively. We measured moisture and ash content, concentrations of Pb, Cd, Zn, Cu, Ni, Cr, and As in the above-ground parts of the plants and in ash produced by combustion of the plants, plus gross calorific values. The plants' phytoextraction and phytostabilisation potential was evaluated based on their bioconcentration factor (BCF) and translocation factor (TF). Mullein was identified as a hyperaccumulator for Cd. It also showed a higher gross calorific value (19,735 kJ kg-1) than ragweed (16,469 kJ kg-1).The results of this study suggest that mullein has a great potential for phytoextraction and for biomass generation, and that ragweed could be an effective tool of phytostabilisation.

  5. Increased consumption and vasodilatory effect of nitrite during exercise

    Science.gov (United States)

    Hon, Yuen Yi; Lin, Elaina E.; Tian, Xin; Yang, Yang; Sun, He; Swenson, Erik R.; Taveira-Dasilva, Angelo M.; Gladwin, Mark T.

    2015-01-01

    This study investigated the effects of aerobic-to-anaerobic exercise on nitrite stores in the human circulation and evaluated the effects of systemic nitrite infusion on aerobic and anaerobic exercise capacity and hemodynamics. Six healthy volunteers were randomized to receive sodium nitrite or saline for 70 min in two separate occasions in an exercise study. Subjects cycled on an upright electronically braked cycle ergometer 30 min into the infusion according to a ramp protocol designed to attain exhaustion in 10 min. They were allowed to recover for 30 min thereafter. The changes of whole blood nitrite concentrations over the 70-min study period were analyzed by pharmacokinetic modeling. Longitudinal measurements of hemodynamic and clinical variables were analyzed by fitting nonparametric regression spline models. During exercise, nitrite consumption/elimination rate was increased by ∼137%. Cardiac output (CO), mean arterial pressure (MAP), and pulmonary artery pressure (PAP) were increased, but smaller elevation of MAP and larger increases of CO and PAP were found during nitrite infusion compared with placebo control. The higher CO and lower MAP during nitrite infusion were likely attributed to vasodilation and a trend toward decrease in systemic vascular resistance. In contrast, there were no significant changes in mean pulmonary artery pressures and pulmonary vascular resistance. These findings, together with the increased consumption of nitrite and production of iron-nitrosyl-hemoglobin during exercise, support the notion of nitrite conversion to release NO resulting in systemic vasodilatation. However, at the dosing used in this protocol achieving micromolar plasma concentrations of nitrite, exercise capacity was not enhanced, as opposed to other reports using lower dosing. PMID:26684248

  6. Potential Use of Polyacrylamide Encapsulation for Treatment of Petroleum Drilling Cuttings and Hydrocarbon Contaminated Soil

    Directory of Open Access Journals (Sweden)

    Randy H. Adams

    2011-07-01

    Full Text Available Mineral soil of alluvial origin, contaminated with diesel+lubricating oil (1:2, was treated with a commercial polyacrylamide product at 100 % of the distributer recommended dosage, producing a reduction in hydrocarbon concentration (EPA 9074 of 76 % that remained stable during the study period (38 days and even after thermal treatment (60 ºC, 18 hrs.. Increasing the dosage to 150 % did not improve the treatment results, but repeating the treatment (at 100 % resulted in a slight additional reduction (4 %. Similar results were obtained with oil-based drilling cuttings (~60 % reduction at both 100 % and 150 %. Pre-drying of the drilling cuttings prior to treatment did not improve the hydrocarbon reduction, but it did produce smaller, potentially more stable aggregates (0.5 – 1-0 mm in diameter. The treatment of organic soil resulted in a similar reduction in hydrocarbon concentration (65 % and a reduction of acute toxicity (Microtox to below background levels, however this effect was not stable. An additional application (including mixing of the polyacrylamide product resulted in partial disintegration of the organic fibres and release of the stabilized hydrocarbons, measuring an overall increase in hydrocarbon concentration of 19 %.

  7. Toxicological benchmarks for screening potential contaminants of concern for effects on soil and litter invertebrates and heterotrophic process

    Energy Technology Data Exchange (ETDEWEB)

    Will, M.E.; Suter, G.W. II

    1994-09-01

    One of the initial stages in ecological risk assessments for hazardous waste sites is the screening of contaminants to determine which of them are worthy of further consideration as {open_quotes}contaminants of potential concern.{close_quotes} This process is termed {open_quotes}contaminant screening.{close_quotes} It is performed by comparing measured ambient concentrations of chemicals to benchmark concentrations. Currently, no standard benchmark concentrations exist for assessing contaminants in soil with respect to their toxicity to soil- and litter-dwelling invertebrates, including earthworms, other micro- and macroinvertebrates, or heterotrophic bacteria and fungi. This report presents a standard method for deriving benchmarks for this purpose, sets of data concerning effects of chemicals in soil on invertebrates and soil microbial processes, and benchmarks for chemicals potentially associated with United States Department of Energy sites. In addition, literature describing the experiments from which data were drawn for benchmark derivation. Chemicals that are found in soil at concentrations exceeding both the benchmarks and the background concentration for the soil type should be considered contaminants of potential concern.

  8. A random-sequential mechanism for nitrite binding and active site reduction in copper-containing nitrite reductase

    NARCIS (Netherlands)

    Wijma, HJ; Jeuken, LJC; Verbeet, MP; Armstrong, FA; Canters, GW

    2006-01-01

    The homotrimeric copper-containing nitrite reductase ( NiR) contains one type-1 and one type-2 copper center per monomer. Electrons enter through the type-1 site and are shuttled to the type-2 site where nitrite is reduced to nitric oxide. To investigate the catalytic mechanism of NiR the effects of

  9. Potential of EnMAP spaceborne imaging spectroscopy for the prediction of common surface soil properties and expected accuracy

    Science.gov (United States)

    Chabrillat, Sabine; Foerster, Saskia; Steinberg, Andreas; Stevens, Antoine; Segl, Karl

    2016-04-01

    There is a renewed awareness of the finite nature of the world's soil resources, growing concern about soil security, and significant uncertainties about the carrying capacity of the planet. As a consequence, soil scientists are being challenged to provide regular assessments of soil conditions from local through to global scales. However, only a few countries have the necessary survey and monitoring programs to meet these new needs and existing global data sets are out-of-date. A particular issue is the clear demand for a new area-wide regional to global coverage with accurate, up-to-date, and spatially referenced soil information as expressed by the modeling scientific community, farmers and land users, and policy and decision makers. Soil spectroscopy from remote sensing observations based on studies from the laboratory scale to the airborne scale has been shown to be a proven method for the quantitative prediction of key soil surface properties in local areas for exposed soils in appropriate surface conditions such as low vegetation cover and low water content. With the upcoming launch of the next generation of hyperspectral satellite sensors in the next 3 to 5 years (EnMAP, HISUI, PRISMA, SHALOM), a great potential for the global mapping and monitoring of soil properties is appearing. Nevertheless, the capabilities to extend the soil properties current spectral modeling from local to regional scales are still to be demonstrated using robust methods. In particular, three central questions are at the forefront of research nowadays: a) methodological developments toward improved algorithms and operational tools for the extraction of soil properties, b) up scaling from the laboratory into space domain, and c) demonstration of the potential of upcoming satellite systems and expected accuracy of soil maps. In this study, airborne imaging spectroscopy data from several test sites are used to simulate EnMAP satellite images at 30 m scale. Then, different soil

  10. The genome of Nitrospina gracilis illuminates the metabolism and evolution of the major marine nitrite oxidizer

    Directory of Open Access Journals (Sweden)

    Sebastian eLuecker

    2013-02-01

    Full Text Available In marine systems, nitrate is the major reservoir of inorganic fixed nitrogen. The only known biological nitrate-forming reaction is nitrite oxidation, but despite its importance, our knowledge of the organisms catalyzing this key process in the marine N-cycle is very limited. The most frequently encountered marine NOB are related to Nitrospina gracilis, an aerobic chemolithoautotrophic bacterium isolated from ocean surface waters. To date, limited physiological and genomic data for this organism were available and its phylogenetic affiliation was uncertain. In this study, the draft genome sequence of Nitrospina gracilis strain 3/211 was obtained. Unexpectedly for an aerobic organism, N. gracilis lacks classical reactive oxygen defense mechanisms and uses the reductive tricarboxylic acid cycle for carbon fixation. These features indicate microaerophilic ancestry and are consistent with the presence of Nitrospina in marine oxygen minimum zones. Fixed carbon is stored intracellularly as glycogen, but genes for utilizing external organic carbon sources were not identified. N. gracilis also contains a full gene set for oxidative phosphorylation with oxygen as terminal electron acceptor and for reverse electron transport from nitrite to NADH. A novel variation of complex I may catalyze the required reverse electron flow to low-potential ferredoxin. Interestingly, comparative genomics indicated a strong evolutionary link between Nitrospina, the nitrite-oxidizing genus Nitrospira, and anaerobic ammonium oxidizers, apparently including the horizontal transfer of a periplasmically oriented nitrite oxidoreductase and other key genes for nitrite oxidation at an early evolutionary stage. Further, detailed phylogenetic analyses using concatenated marker genes provided evidence that Nitrospina forms a novel bacterial phylum, for which we propose the name Nitrospinae.

  11. Soil radon measurements as potential tracer of seismic and volcanic activity at Etna

    Science.gov (United States)

    Neri, Marco; Giammanco, Salvatore; Galli, Gianfranco; Ferrera, Elisabetta

    2014-05-01

    Radon is a radioactive noble gas present in all rocks of the Earth. It's used by the scientific community as a tracer of natural phenomena related to outgassing from the soil along faults, fractures and crustal discontinuity. Recently, radon has also been used on active volcanoes such as Etna, both as a precursor of volcanic phenomena as well as in the study of the dynamics of faults. The Istituto Nazionale di Geofisica e Vulcanologia (INGV) performs discrete and continuous measurements of radon from soil at Etna since 2002. First studies concerned measurements of radon and thoron emissions from soil carried out on the E and SW flanks of Etna, in zones characterized by the presence of numerous seismogenic and aseismic faults. The statistical treatment of the geochemical data allowed recognizing anomaly thresholds, producing distribution maps that highlighted a significant spatial correlation between soil gas anomalies and tectonic lineaments. These studies confirmed that mapping the distribution of radon and thoron in soil gas can reveal hidden faults buried by recent soil cover. INGV permanent radon monitoring network was installed in July 2005. First results were obtained during the July 2006 eruption. The radon signal recorded at Torre del Filosofo (TdF, ~2950 m asl) was compared with volcanic tremor and thermal radiance data. The onset of explosive activity and a lava fountaining episode were preceded by some hours with increases in radon activity and more gradual increases in volcanic tremor. After 2006, Etna produced dozens of paroxysmal episodes from a new vent opened on the eastern flank of the Southeast Crater (summit area), that have built up a new, huge pyroclastic cone. In many cases we observed increase in radon activity some hours before the eruptive events. These observations suggest that radon emissions from the TdF zone are sensitive to the local geodynamic pressure induced by magma dynamics in the conduit systems. Other promising results were

  12. Laboratory experiments with growth potential of Cenangium ferruginosum tested on natural nutrition soils

    Directory of Open Access Journals (Sweden)

    Kunca Andrej

    2013-03-01

    Full Text Available Serious pine dieback was reported in early spring from several localities in Slovakia in 2012. Needle necrosis, bark necrosis and twig cankers were the most conspicuous symptoms on diseased trees. There were no or at least not significant damages caused by bark beetles, leaf eating insects, root rots neither tracheomycosis. We also excluded Sphaeropsis sapinea (Fr. Dyko & B. Sutton as the main pest agent, which played an important role in Pinus nigra Arnold dieback from 2000 to 2007 in Slovakia. Our laboratory inspections revealed Cenangium ferruginosum Fr. as the agent responsible for that dieback. We tested its growth capability on different natural nutrition soils in the laboratory to see the potential pathogenecity. This paper describes the pine dieback based on the field inspections and laboratory studies, and we discuss the role of predisposing factors involved in the dieback.

  13. Plasma nitrate and nitrite are increased by a high nitrate supplement, but not by high nitrate foods in older adults

    Science.gov (United States)

    Miller, Gary D.; Marsh, Anthony P.; Dove, Robin W.; Beavers, Daniel; Presley, Tennille; Helms, Christine; Bechtold, Erika; King, S. Bruce; Kim-Shapiro, Daniel

    2012-01-01

    Little is known about the effect of dietary nitrate on the nitrate/nitrite/NO (nitric oxide) cycle in older adults. We examined the effect of a 3-day control diet vs. high nitrate diet, with and without a high nitrate supplement (beetroot juice), on plasma nitrate and nitrite kinetics, and blood pressure using a randomized four period cross-over controlled design. We hypothesized that the high nitrate diet would show higher levels of plasma nitrate/nitrite and blood pressure compared to the control diet, which would be potentiated by the supplement. Participants were eight normotensive older men and women (5 female, 3 male, 72.5±4.7 yrs) with no overt disease or medications that affect NO metabolism. Plasma nitrate and nitrite levels and blood pressure were measured prior to and hourly for 3 hours after each meal. The mean daily changes in plasma nitrate and nitrite were significantly different from baseline for both control diet+supplement (p<0.001 and =0.017 for nitrate and nitrite, respectively) and high nitrate diet+supplement (p=0.001 and 0.002), but not for control diet (p=0.713 and 0.741) or high nitrate diet (p=0.852 and 0.500). Blood pressure decreased from the morning baseline measure to the three 2 hr post-meal follow-up time-points for all treatments, but there was no main effect for treatment. In healthy older adults, a high nitrate supplement consumed at breakfast elevated plasma nitrate and nitrite levels throughout the day. This observation may have practical utility for the timing of intake of a nitrate supplement with physical activity for older adults with vascular dysfunction. PMID:22464802

  14. Harmful potential toxic elements in greenhouse soils under long-term cultivation in Almería (Spain)

    Science.gov (United States)

    Joaquin Ramos-Miras, Jose; Rodríguez Martín, Jose Antonio; Boluda, Rafael; Bech, Jaume; Gil, Carlos

    2014-05-01

    Heavy metals (HM) are considered highly significant environmental contaminants and are the object of many scientific research works into the soil environment. Activities like agriculture or industry can increase the concentration of these contaminants in soils and waters, which can affect the food chain. Intensification of certain agricultural practices, constant and excessive use of fertilizers and phytosanitary products, and using machinery, increase the HM content in agricultural soils. Many studies have dealt with HM accumulation over time. Despite these works, the influence of long periods of time on these contents, the dynamics and evolution of these elements in agricultural soils, especially soils used for intensive farming purposes under greenhouse conditions, remain unknown to a certain extent. The western Almería region (Spain) is a very important area from both the socio-economic and agricultural viewpoints. A common practice in greenhouse agriculture is the addition of agrochemicals to soils and crops to improve nutrient supply or crop protection and disease control. Such intense agricultural activity has a strong impact, which may have negative repercussions on both these greenhouse soils and the environment. A research has been carried out to determine the total and available levels of six harmful potentially toxic elements (Cd, Cu, Pb, Ni, Zn and Co), and to assess long-term variations in the greenhouse soils of western Almeria. The results indicate that managing soils in the greenhouse preparation stage determines major changes in total and available HM contents. Furthermore, Cd, Cu and Pb enrichment in soil was observed depending on the element and years of growth.

  15. Increasing microbial diversity and nitrogen cycling potential of burnt forest soil in Spain through post-fire management

    Science.gov (United States)

    Pereg, Lily; Mataix-Solera, Jorge; McMillan, Mary; García-Orenes, Fuensanta

    2016-04-01

    Microbial diversity and function in soils are increasingly assessed by the application of molecular methods such as sequencing and PCR technology. We applied these techniques to study microbial recovery in post-fire forest soils. The recovery of forest ecosystems following severe fire is influenced by post-fire management. The removal of burnt tree stumps (salvage logging) is a common practice in Spain following fire. In some cases, the use of heavy machinery in addition to the vulnerability of soils to erosion and degradation make this management potentially damaging to soil, and therefore to the ecosystem. We hypothesized that tree removal slows down the recovery of soil biological communities including microbial and plant communities and contributes to soil degradation in the burnt affected area. The study area is located in "Sierra de Mariola Natural Park" in Alcoi, Alicante (E Spain). A big forest fire (>500 has) occurred in July 2012. The forest is composed mainly of Pinus halepensis trees with an understory of typical Mediterranean shrubs species such as Quercus coccifera, Rosmarinus officinalis, Thymus vulgaris, Brachypodium retusum, etc. Soil is classified as a Typic Xerorthent (Soil Survey Staff, 2014) developed over marls. In February 2013, salvage logging (SL) treatment, with a complete extraction of the burned wood using heavy machinery, was applied to a part of the affected forest. Plots for monitoring the effects of SL were installed in this area and in a similar nearby control (C) area, where no SL treatment was done. The recovery of soil bacterial and fungal communities post-fire with and without tree removal was analysed by using Next-Generation sequencing and the abundance of functional genes, related to nitrogen cycling, in the soil was estimated using quantitative PCR (qPCR). We will present the methods used and the results of our study in this PICO presentation.

  16. The potential of beech seedlings to adapt to low P availability in soil - plant versus microbial effects on P mobilising potential in the rhizosphere

    Science.gov (United States)

    Meller, Sonia; Frey, Beat; Frossard, Emmanuel; Spohn, Marie; Schack-Kirchner, Helmer; Luster, Jörg

    2016-04-01

    rhizoplane was mostly determined by the soil and was affected only to a small degree by plant provenance. On the other hand, plant provenance appeared to affect the occurrence of oxalate in the rhizosphere. The observed pH gradients near the root reflect the production of nitrate in the soil and the plant nitrate uptake. These results suggest, that the potential to hydrolyse organic P in the rhizosphere is mainly governed by the existing soil microbial community, while the plant itself actively influence the mobilisation of inorganic P by root exudation of carboxylates or possibly by stimulating the carboxylate exudation by specific microorganisms.

  17. Net mineralization of N at deeper soil depths as a potential mechanism for sustained forest production under elevated [CO2

    Energy Technology Data Exchange (ETDEWEB)

    Iversen, Colleen M [ORNL; Hooker, Toby [Utah State University (USU); Classen, Aimee T [University of Tennessee, Knoxville (UTK); Norby, Richard J [ORNL

    2011-01-01

    Elevated atmospheric [CO2] is projected to increase forest production, which could increase ecosystem carbon (C) storage. However, sustained forest production will depend on the nutrient balance of the forested ecosystem. Our aim was to examine the causes and consequences of increased fine-root production and mortality throughout the soil profile under elevated CO2 with respect to potential gross nitrogen (N) cycling rates. Our study was conducted in a CO2-enriched sweetgum (Liquidambar styraciflua L.) plantation in Oak Ridge, TN, USA. We used isotope pool dilution methodology to measure potential gross N cycling rates in laboratory incubations of soil from four depth increments to 60 cm. Our objectives were two-fold: (1) determine whether N is available for root acquisition in deeper soil, and (2) determine whether increased inputs of labile C from greater fine-root mortality at depth under elevated [CO2] had altered N cycling rates. While gross N fluxes declined with soil depth, we found that N is potentially available for roots to access, especially below 15 cm depth where microbial consumption of mineral N was reduced. Overall, up to 60% of potential gross N mineralization, and 100% of potential net N mineralization, occurred below 15-cm depth at this site. This finding was supported by in situ measurements from ion-exchange resins, where total inorganic N availability at 55 cm depth was equal to or greater than N availability at 15 cm depth. While it is likely that trees grown under elevated [CO2] are accessing a larger pool of inorganic N by mining deeper soil, we found no effect of elevated [CO2] on potential gross or net N cycling rates. Thus, increased root exploration of the soil volume under elevated [CO2] may be more important than changes in potential gross N cycling rates in sustaining forest responses to rising atmospheric CO2.

  18. Evaluation of scour potential of cohesive soils : final report, August 2009.

    Science.gov (United States)

    2009-08-01

    Prediction of scour at bridge river crossings is an evolving process. Hydraulic models to estimate water velocity and, therefore, the shear stresses that erode soil are reasonably well developed. The weak link remains methods for estimating soil erod...

  19. Monitoring soil sealing in Guadarrama River basin, Spain, and its potential impact in agricultural areas

    OpenAIRE

    Eugenia Pérez; Pilar García

    2016-01-01

    This study analyzes soil sealing and its repercussions in the loss of fertile soils, which are more appropriate for agriculture use. Also, soil sealing increases flood risk. The main objective is to estimate soil loss by sealing in the Guadarrama River Basin (Madrid, Spain) between 1961 and 2011. The combination of digital processing (Normalized Difference Vegetation Index (NDVI), principal components and convolution filters) of satellite imagery with the digital terrain model helps to detect...

  20. Non-native plants and soil microbes: potential contributors to the consistent reduction in soil aggregate stability caused by the disturbance of North American grasslands.

    Science.gov (United States)

    Duchicela, Jessica; Vogelsang, Keith M; Schultz, Peggy A; Kaonongbua, Wittaya; Middleton, Elizabeth L; Bever, James D

    2012-10-01

    Soil aggregate stability is an important ecosystem property that is altered by anthropogenic disturbance. Yet, the generalization of these alterations and the identification of the main contributors are limited by the absence of cross-site comparisons and the application of inconsistent methodologies across regions. • We assessed aggregate stability in paired remnant and post-disturbance grasslands across California, shortgrass and tallgrass prairies, and in manipulative experiments of plant composition and soil microbial inoculation. • Grasslands recovering from anthropogenic disturbance consistently had lower aggregate stability than remnants. Across all grasslands, non-native plant diversity was significantly associated with reduced soil aggregate stability. A negative effect of non-native plants on aggregate stability was also observed in a mesocosm experiment comparing native and non-native plants from California grasslands. Moreover, an inoculation study demonstrated that the degradation of the microbial community also contributes to the decline in soil aggregate stability in disturbed grasslands. • Anthropogenic disturbance consistently reduced water-stable aggregates. The stability of aggregates was reduced by non-native plants and the degradation of the native soil microbial community. This latter effect might contribute to the sustained decline in aggregate stability following anthropogenic disturbance. Further exploration is advocated to understand the generality of these potential mechanisms. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  1. An evaluation of soil colonisation potential of selected fungi and their production of ligninolytic enzymes for use in soil bioremediation applications.

    Science.gov (United States)

    McErlean, Colum; Marchant, Roger; Banat, Ibrahim M

    2006-08-01

    Initially sixteen fungi were screened for potential ligninolytic activity using decolourisation of a polymeric dye Poly R-478. From this, four fungi were selected, Trametes versicolor, Pleurotus ostreatus, Collybia sp., and an isolate (identified as Rhizoctonia solani) isolated from a grassland soil. Differences in the ligninolytic enzyme profiles of each of the fungi were observed. All of the four fungi tested produced MnP and laccase while the Collybia sp. and R. solani produced LiP in addition. Enzyme activity levels also varied greatly over the 21 days of testing with T. versicolor producing levels of MnP and laccase three to four times greater than the other fungi. The four fungi were then tested for their ability to colonise sand, peat (forest) and basalt and marl mixed till (field) soils through visual measurement and biomass detection in soil microcosms. Trametes versicolor and the Collybia sp. failed to grow in any of the non-sterilised soils whereas the R. solani and P. ostreatus isolates grew satisfactorily. Primers were designed to detect MnP and laccase genes in P. ostreatus and RTPCR was used to detect that these genes are expressed in forest and field soils.

  2. It is rocket science - why dietary nitrate is hard to 'beet'! Part I: twists and turns in the realization of the nitrate-nitrite-NO pathway.

    Science.gov (United States)

    Khatri, Jibran; Mills, Charlotte Elizabeth; Maskell, Perry; Odongerel, Chimed; Webb, Andrew James

    2017-01-01

    Dietary nitrate (found in green leafy vegetables, such as rocket, and in beetroot) is now recognized to be an important source of nitric oxide (NO), via the nitrate-nitrite-NO pathway. Dietary nitrate confers several cardiovascular beneficial effects on blood pressure, platelets, endothelial function, mitochondrial efficiency and exercise. While this pathway may now seem obvious, its realization followed a rather tortuous course over two decades. Early steps included the discovery that nitrite was a source of NO in the ischaemic heart but this appeared to have deleterious effects. In addition, nitrate-derived nitrite provided a gastric source of NO. However, residual nitrite was not thought to be absorbed systemically. Nitrite was also considered to be physiologically inert but potentially carcinogenic, through N-nitrosamine formation. In Part 1 of a two-part Review on the nitrate-nitrite-NO pathway we describe key twists and turns in the elucidation of the pathway and the underlying mechanisms. This provides the critical foundation for the more recent developments in the nitrate-nitrite-NO pathway which are covered in Part 2. © 2016 The British Pharmacological Society.

  3. The potential of hyperspectral patterns of winter wheat to detect changes in soil microbial community composition

    NARCIS (Netherlands)

    Almeida De Carvalho, Sabrina; Putten, van der Wim H.; Hol, W.H.G.

    2016-01-01

    Reliable information on soil status and crop health is crucial for detecting and mitigating disasters like pollution or minimizing impact from soil-borne diseases. While infestation with an aggressive soil pathogen can be detected via reflected light spectra, it is unknown to what extent

  4. Limitations and potential of spectral subtractions in fourier-transform infrared (FTIR) spectroscopy of soil samples

    Science.gov (United States)

    Soil science research is increasingly applying Fourier transform infrared (FTIR) spectroscopy for analysis of soil organic matter (SOM). However, the compositional complexity of soils and the dominance of the mineral component can limit spectroscopic resolution of SOM and other minor components. The...

  5. What the soil reveals: potential total ecosystem C stores of the Pacific Northwest region, USA.

    Science.gov (United States)

    Peter S. Homann; Mark Harmon; Suzanne Remillard; Erica A.H. Smithwick

    2005-01-01

    How much organic C can a region naturally store in its ecosystems? How can this be determined, when land management has altered the vegetation of the landscape substantially? The answers may lie in the soil: this study synthesized the spatial distribution of soil properties derived from the state soils geographic database with empirical measurements of old-growth...

  6. Three-Dimensional Soil Landscape Modeling: A Potential Earth Science Teaching Tool

    Science.gov (United States)

    Schmid, Brian M.; Manu, Andrew; Norton, Amy E.

    2009-01-01

    Three-dimensional visualization is helpful in understanding soils, and three dimensional (3-D) tools are gaining popularity in teaching earth sciences. Those tools are still somewhat underused in soil science, yet soil properties such as texture, color, and organic carbon content vary both vertically and horizontally across the landscape. These…

  7. Comparative Assessment of Soil Organic Carbon Stock Potential under Agroforestry Practices and Other Land Uses in Lowlands of Bale

    Directory of Open Access Journals (Sweden)

    Bikila Mengistu

    2017-08-01

    Full Text Available Soil organic carbon is the carbon associated with soil organic matter that is made up of decomposed plant and animal materials. This study was conducted in Dallo Mena district to estimate the amount of soil carbon stock stored in shade grown coffee (SC and homegarden agroforestry practices (HG, and adjacent natural forest (NF and annual crop field (CF and to show the potential of agroforestry practices in soil organic carbon storage capacity. The study site was selected based on spatial analogue approach. From each land uses nine plots were selected by using systematic sampling method following the transect line. Soil organic carbon stock (100cm depth were the highest for the NF(170.11 ± 14.59 Mg ha-1, followed by SC(127.96 ± 9.43 Mg ha-1, HG(107.62 ± 12.55 Mg ha-1 and CF(97.56 ± 6.85 Mg ha-1. Agroforestry and other land uses of Dallo Mena districts are providing various ecological as well as economical benefits for the community. It is used as income source, conserving different plant species diversity and at the same time storing large amounts of soil organic carbon. Therefore, there is significant difference among natural forest, shade grown coffee agroforestry practice, homegarden agroforestry practice and annual crop field in soil organic carbon storage capacity.International Journal of EnvironmentVolume-6, Issue-3, Jun-Aug 2017, page: 1-14

  8. Accumulation and leaching potential of some pharmaceuticals and potential endocrine disruptors in soils irrigated with wastewater in the Tula Valley, Mexico.

    Science.gov (United States)

    Gibson, Richard; Durán-Álvarez, Juan C; Estrada, Karina León; Chávez, Alma; Jiménez Cisneros, Blanca

    2010-12-01

    The reuse of wastewater for irrigation of agricultural land is a well established practice but introduces many contaminants into the terrestrial environment including pharmaceuticals and personal care products. This study reports the persistence and leaching potential of a group of acidic pharmaceuticals, carbamazepine, and three endocrine disruptors in soils from the Tula Valley in Mexico, one of the largest irrigation districts in the world that uses untreated wastewater. After irrigation of soil columns with fortified wastewater over the equivalent of one crop cycle, between 0% and 7% of the total added amounts of ibuprofen, naproxen, and diclofenac and between 0% and 25% of 4-nonylphenol, triclosan, and bisphenol-A were recovered from the soil profiles. Carbamazepine was more persistent, between 55% and 107% being recovered. Amounts in leachates suggested that movement through the soil was possible for all of the analytes, particularly in profiles of low organic matter and clay content. Analysis of soil samples from the Tula Valley confirmed the general lack of accumulation of the acidic pharmaceuticals (concentrations from below the limit of detection to 0.61 μgkg(-1)) and endocrine disruptors (concentrations from below the limit of detection to 109 μgkg(-1)) despite continual addition through regular irrigation with untreated wastewater; there was little evidence of movement through the soil profiles. In contrast, carbamazepine was present in horizon A of the soil at concentrations equivalent to several years of additions by irrigation (2.6-7.5 μgkg(-1)) and was also present in the deeper horizons. The persistence and mobility of carbamazepine suggested a potential to contaminate groundwater. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Application of fast pyrolysis biochar to a loamy soil - Effects on carbon and nitrogen dynamics and potential for carbon sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Bruun, E.W.

    2011-05-15

    of FP-biochar (10 wt%) in a sandy loam soil improved the water holding capacity (WHC) by 32 %, while the SP-biochar reference only increased it moderately. Moreover, soil amendment of FP-biochar caused immobilization of considerable amounts of soil N, whereas SP-biochar resulted in a net mineralization of N after two months of soil incubation. Nitrogen immobilisation can be detrimental to crop yields, as shown in a Barley pot trial in this thesis, but may, on the other hand, constitute an advantage during e.g. fallow periods by preventing N leaching. Moreover, when it comes to the mobility of biochar in soil, FP-biochars acted considerably differently to SP-biochar. FP-biochar contained highly mobile carbon components (nm-scale), which followed the downward movement of water. By contrast, C components from slow pyrolysis biochar were retained in the topsoil. In summary, the research of this thesis shows that, compared to its more inert 'traditional biochar counter-part' made by slow pyrolysis, FP-biochar, in a number of ways, acts more like the original organic matter feedstock when added to soil. Yet, on the longer term the effects are likely a transient phenomenon, as the labile part is used up after a few months, leaving a much more recalcitrant FP-biochar. It is still too early to recommend - or discourage - FP-biochar for agronomic use, since field trials are needed in order to verify potential benefits or drawbacks on soil fertility and crop yields. However, this thesis has improved the mechanistic understanding of the effects of applying FP-biochar to soil, and shows that wheat-straw FP-biochar has properties beneficial for agricultural soil, e.g. it improves soil WHC, adds minerals, enhances microbial activity/biomass, and increases the N and C turnover dynamics. (Author)

  10. Potential nitrogen fixation activity of different aged biological soil crusts from rehabilitated grasslands of the hilly Loess Plateau, China

    Science.gov (United States)

    Zhao, Y.; Xu, M.; Belnap, J.

    2010-01-01

    Biological soil crusts (biocrusts) cover up to 60–70% of the soil surface in grasslands rehabilitated during the "Grain for Green" project implemented in the hilly Loess Plateau region in 1999. As biocrusts fix nitrogen (N), they are an important part of restoring soil fertility. We measured nitrogenase activity (NA) in biocrusts from sites rehabilitated at six different time periods to estimate 1) the effects of moisture content and temperature on NA in biocrusts of different ages and 2) the potential N contribution from biocrusts to soils and plants in this region. Results show that NA in the biocrusts was mostly controlled by the species composition, as the activity of biocrusts dominated by free-living soil cyanobacteria was significantly higher than that of moss-dominated biocrusts. Nitrogenase activity was also influenced by soil moisture content and ambient temperature, with a significant decline in activity when moisture levels were decreased to 20% field water-holding capacity. The optimal temperature for NA was 35–40 °C and 30–40 °C for cyanobacteria- and moss-dominated biocrusts, respectively. Biocrust fixed N is likely an important source of N in this ecosystem, as we estimated annual potential N inputs per hectare in these grasslands to be up to 13 kg N ha-1 and 4 kg N ha-1 for cyanobacteria- and moss-dominated biocrusts, respectively.

  11. Estimates of potential childhood lead exposure from contaminated soil using the US EPA IEUBK Model in Sydney, Australia.

    Science.gov (United States)

    Laidlaw, Mark A S; Mohmmad, Shaike M; Gulson, Brian L; Taylor, Mark P; Kristensen, Louise J; Birch, Gavin

    2017-07-01

    Surface soils in portions of the Sydney (New South Wales, Australia) urban area are contaminated with lead (Pb) primarily from past use of Pb in gasoline, the deterioration of exterior lead-based paints, and industrial activities. Surface soil samples (n=341) were collected from a depth of 0-2.5cm at a density of approximately one sample per square kilometre within the Sydney estuary catchment and analysed for lead. The bioaccessibility of soil Pb was analysed in 18 samples. The blood lead level (BLL) of a hypothetical 24 month old child was predicted at soil sampling sites in residential and open land use using the United States Environmental Protection Agency (US EPA) Integrated Exposure Uptake and Biokinetic (IEUBK) model. Other environmental exposures used the Australian National Environmental Protection Measure (NEPM) default values. The IEUBK model predicted a geometric mean BLL of 2.0±2.1µg/dL using measured soil lead bioavailability measurements (bioavailability =34%) and 2.4±2.8µg/dL using the Australian NEPM default assumption (bioavailability =50%). Assuming children were present and residing at the sampling locations, the IEUBK model incorporating soil Pb bioavailability predicted that 5.6% of the children at the sampling locations could potentially have BLLs exceeding 5µg/dL and 2.1% potentially could have BLLs exceeding 10µg/dL. These estimations are consistent with BLLs previously measured in children in Sydney. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Community analysis of ammonia and nitrite oxidizers during start-up of nitritation reactors.

    Science.gov (United States)

    Egli, Konrad; Langer, Christian; Siegrist, Hans-Ruedi; Zehnder, Alexander J B; Wagner, Michael; van der Meer, Jan Roelof

    2003-06-01

    Partial nitrification of ammonium to nitrite under oxic conditions (nitritation) is a critical process for the effective use of alternative nitrogen removal technologies from wastewater. Here we investigated the conditions which promote establishment of a suitable microbial community for performing nitritation when starting from regular sewage sludge. Reactors were operated in duplicate under different conditions (pH, temperature, and dilution rate) and were fed with 50 mM ammonium either as synthetic medium or as sludge digester supernatant. In all cases, stable nitritation could be achieved within 10 to 20 days after inoculation. Quantitative in situ hybridization analysis with group-specific fluorescent rRNA-targeted oligonucleotides (FISH) in the different reactors showed that nitrite-oxidizing bacteria of the genus Nitrospira were only active directly after inoculation with sewage sludge (up to 4 days and detectable up to 10 days). As demonstrated by quantitative FISH and restriction fragment length polymorphism (RFLP) analyses of the amoA gene (encoding the active-site subunit of the ammonium monooxygenase), the community of ammonia-oxidizing bacteria changed within the first 15 to 20 days from a more diverse set of populations consisting of members of the Nitrosomonas communis and Nitrosomonas oligotropha sublineages and the Nitrosomonas europaea-Nitrosomonas eutropha subgroup in the inoculated sludge to a smaller subset in the reactors. Reactors operated at 30 degrees C and pH 7.5 contained reproducibly homogeneous communities dominated by one amoA RFLP type from the N. europaea-N. eutropha group. Duplicate reactors at pH 7.0 developed into diverse communities and showed transient population changes even within the ammonia oxidizer community. Reactors at pH 7.5 and 25 degrees C formed communities that were indistinguishable by the applied FISH probes but differing in amoA RFLP types. Communities in reactors fed with sludge digester supernatant exhibited a

  13. Impact of future climatic conditions on the potential for soil organic matter priming

    DEFF Research Database (Denmark)

    Reinsch, Sabine; Ambus, Per; Thornton, Barry

    2013-01-01

    . Soil samples were taken from a heath-land after six years of exposure to elevated carbon dioxide (eCO2) in combination with summer drought (D) and increased temperature (T). Soil C-dynamics were investigated in soils from: (i) ambient, (ii) eCO2, and (iii) plots exposed to the combination of factors...... affect soil processes; these factors may counterbalance each other and maintain ecosystem stability. This highlights the importance of studying climate change factors in combination to fully assess consequences of environmental change on plant-soil systems. © 2013 Elsevier Ltd....

  14. Impact of mitochondria on nitrite metabolism in HL-1 cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Peter eDungel

    2013-05-01

    Full Text Available Apart from ATP synthesis mitochondria have many other functions, one being nitrite reductase activity. NO released from nitrite has been shown to protect the heart from ischemia/reperfusion injury in a cGMP-dependent manner. However, the exact impact of mitochondria on the release of NO from nitrite in cardiomyocytes is not completely understood. Besides mitochondria, a number of non-mitochondrial metalloproteins have been suggested to facilitate this process. The aim of this study was to investigate the impact of mitochondria on the bioactivation of nitrite in HL-1 cardiomyocytes.The levels of nitrosyl complexes of hemoglobin (NO-Hb and cGMP levels were measured by electron spin resonance spectroscopy and enzyme immunoassay. In addition the formation of free NO was determined by confocal microscopy as well as intracellular nitrite and S-nitrosothiols by chemoluminescence analysis. NO was released from nitrite in cell culture in an oxygen dependent manner. Application of specific inhibitors of the respiratory chain, p450, NO synthases and xanthine oxidoreductase showed that all four enzymatic systems are involved in the release of NO, but more than 50% of NO is released via the mitochondrial pathway. Only NO released by mitochondria activated cGMP synthesis. Cardiomyocytes co-cultured with red blood cells (RBC competed with RBC for nitrite, but free NO was detected only in HL-1 cells suggesting that RBC are not a source of NO in this model. Apart from activation of cGMP synthesis, NO formed in HL-1 cells diffused out of the cells and formed NO-Hb complexes. In addition nitrite was converted by HL-1 cells to S-nitrosyl complexes. In HL-1 cardiomyocytes, several enzymatic systems are involved in nitrite reduction to NO but only the mitochondrial pathway of NO release activates cGMP synthesis. Our data suggest that this pathway may be a key regulator of myocardial contractility especially under hypoxic conditions.

  15. Combined exposure to ambient UVB radiation and nitrite negatively affects survival of amphibian early life stages

    OpenAIRE

    Macías, Guadalupe; Marco, Adolfo; Blaustein, Andrew R.

    2007-01-01

    Many aquatic species are sensitive to ambient levels of ultraviolet-B radiation (UVB) and chemical fertilizers. However, recent studies indicate that the interaction among multiple stressors acting simultaneously could be contributing to the population declines of some animal species. Therefore, we tested the potential synergistic effects between ambient levels of UVB and a contaminant, sodium nitrite in the larvae of two amphibian species, the common European toad Bufo bufo and the Iberian g...

  16. Effect of Swiss Chard (Beta vulgaris var. cicla) as Nitrite Replacement on Color Stability and Shelf-Life of Cooked Pork Patties during Refrigerated Storage.

    Science.gov (United States)

    Shin, Dong-Min; Hwang, Ko-Eun; Lee, Cheol-Won; Kim, Tae-Kyung; Park, Yoo-Sun; Han, Sung Gu

    2017-01-01

    In this study, the effects of pre-converted nitrite from Swiss chard powder (PS) on the color stability and shelf-life of cooked pork patties during refrigerated storage for 28 d were investigated. Nitrite was added at a concentration of approximately 120 ppm. Five treatments were formulated as follows: Control (120 ppm nitrite), T1 (2% PS), T2 (2% pre-converted nitrite from celery powder; PC), T3 (1% PS + 60 ppm nitrite), and NC (nitrite-free). The T1 and T3 samples had higher nitrosoheme pigment contents, which were associated with the redness of the samples ( p <0.05). T1 resulted in the highest redness value ( p <0.05). The redness and yellowness of the cooked pork patties increased with increasing PS levels. The pH of the samples subjected to all treatments decreased with progress of the storage period ( p <0.05). The pH of the T1 and T3 samples treated with PS was lower ( p <0.05) than that obtained with other treatments, as PS has a lower pH value. The treatments in which PS was added were most effective for reducing the level of thiobarbituric acid reactive substances (TBARS) and the residual nitrite content relative to the control. T1 resulted in the highest flavor, off-flavor, and overall acceptability scores during storage ( p <0.05). The total viable bacterial count for all treatments was below 1 Log CFU/g, and E. coli and coliform bacteria were not detected during storage. Therefore, these results suggested that pre-converted nitrite from Swiss chard powder is a potential replacement for nitrite in meat products.

  17. Estimated Dietary Intake of Nitrite and Nitrate in Swedish Children

    OpenAIRE

    2011-01-01

    Abstract This study examined the intake of nitrate and nitrite in Swedish children. Daily intake estimates were based on a nationwide food consumption survey (4-day food diary) and nitrite/nitrate content in vegetables, fruit, cured meat and water. The mean intake of nitrite from cured meat among 2259 children studied was 0.013, 0.010 and 0.007 mg kg-1 body weight day-1 in age groups 4, 8-9 and 11-12, respectively. Among these age groups, three individuals (0.1% of the studied chil...

  18. Toxicity, analgesic and sedative potential of crude extract of soil-borne phytopathogenic fungi Aspergillus flavus

    Directory of Open Access Journals (Sweden)

    Bashir Ahmad

    2016-11-01

    Full Text Available Background: Aspergillus flavus is one of the most abundant mold present around the world. The present study was conducted to investigate the acute toxicity, analgesic and sedative effect of the crude extract obtained from soil borne fungi A. flavus. Methods: The fungi was isolated from soil samples and identified morphologically and microscopically. The growth condition i.e. media, temperature, pH, and incubation period were optimized. In these optimized growth condition, A. flavus was grown in batch culture in shaking incubator. Crude contents were extracted by using ethyl acetate solvent. Crude secondary metabolites were screened for acute toxicity, analgesic and sedative effect. Results: Upon completion of the experiment, blood was collected from the tail vein of albino mice, and different haematological tests were conducted. White blood cells counts displayed a slight increase (10.6× 109/L above their normal range (0.8–6.8 × 109/L, which may be due to the increment in the number of lymphocytes or granulocytes. However, the percentage of lymphocytes was much lower (17.7%, while the percentage of the granulocytes was higher (61.4% than its normal range (8.6–38.9%. A reduction in the mean number of writhing in the different test groups was caused by the application of the crude ethyl acetate extract through the i.p. route at different doses (50, 100, and 150 mg/kg body weight. The results of our investigation showed the EtOAc extract of A. flavus can cause a significant sedative effect in open field. Conclusion: It was concluded from the present study that the A. flavus has the potential to produce bioactive metabolites which have analgesic and sedative effect.

  19. Calcium ion binding to a soil fulvic acid using a Donnan Potential model

    Energy Technology Data Exchange (ETDEWEB)

    Marinsky, J.A. [State Univ. of New York, Albany, NY (United States). Dept. of Chemistry; Mathuthu, A. [National Univ. of Science and Technology, Bulawayo (Zimbabwe). Dept. of Applied Chemistry; Ephraim, J.H. [Linkoeping Univ. (Sweden). Dept. of Theme Research, Water and Environmental Studies; Reddy, M.M. [Geological Survey, Boulder, CO (United States)

    1999-10-01

    Calcium ion binding to a soil fulvic acid (Armadale Bh Horizon) was evaluated over a range of calcium ion concentrations, from pH 3.8 to 7.3, using potentiometric titrations and calcium ion electrode measurements. Fulvic acid concentration was constant (100 milligrams per liter) and calcium ion concentration varied up to 8 x 10{sup -4} moles per liter. Experiments discussed here included: (1) titrations of fulvic acid-calcium ion containing solutions with sodium hydroxide; and (2) titrations of fully neutralized fulvic acid with calcium chloride solutions. Apparent binding constants (expressed as the logarithm of the value, log {beta}{sub app}) vary with solution pH, calcium ion concentration, degree of acid dissociation, and ionic strength (from log {beta}{sub app}=2.5 to 3.9) and are similar to those reported by others. Fulvic acid charge, and the associated Donnan Potential, influences calcium ion-fulvic acid ion pair formation. A Donnan Potential correction term allowed calculation of intrinsic calcium ion-fulvic acid binding constants. Intrinsic binding constants vary from 1.2 to 2.5 (the average value is about log {beta}=1.6) and are similar to, but somewhat higher than, stability constants for calcium ion-carboxylic acid monodentate complexes. (orig.)

  20. The potential of genetic engineering of plants for the remediation of soils contaminated with heavy metals.

    Science.gov (United States)

    Fasani, Elisa; Manara, Anna; Martini, Flavio; Furini, Antonella; DalCorso, Giovanni

    2017-04-07

    The genetic engineering of plants to facilitate the reclamation of soils and waters contaminated with inorganic pollutants is a relatively new and evolving field, benefiting from the heterologous expression of genes that increase the capacity of plants to mobilize, stabilize and/or accumulate metals. The efficiency of phytoremediation relies on the mechanisms underlying metal accumulation and tolerance, such as metal uptake, translocation and detoxification. The transfer of genes involved in any of these processes into fast-growing, high-biomass crops may improve their reclamation potential. The successful phytoextraction of metals/metalloids and their accumulation in aerial organs have been achieved by expressing metal ligands or transporters, enzymes involved in sulfur metabolism, enzymes that alter the chemical form or redox state of metals/metalloids and even the components of primary metabolism. This review article considers the potential of genetic engineering as a strategy to improve the phytoremediation capacity of plants in the context of heavy metals and metalloids, using recent case studies to demonstrate the practical application of this approach in the field. © 2017 John Wiley & Sons Ltd.

  1. Investigation of antioxidative and anticancer potentials of Streptomyces sp. MUM256 isolated from Malaysia mangrove soil

    Directory of Open Access Journals (Sweden)

    Tan Loh eTeng Hern

    2015-11-01

    Full Text Available A Streptomyces strain, MUM256 was isolated from Tanjung Lumpur mangrove soil in Malaysia. Characterization of the strain showed that it has properties consistent with those of the members of the genus Streptomyces. In order to explore the potential bioactivities, extract of the fermented broth culture of MUM256 was prepared with organic solvent extraction method. DPPH and SOD activity were utilized to examine the antioxidant capacity and the results have revealed the potency of MUM256 in superoxide anion scavenging activity in dose-dependent manner. The cytotoxicity of MUM256 extract was determined using cell viability assay against 8 different panels of human cancer cell lines. Among all the tested cancer cells, HCT116 was the most sensitive toward the extract treatment. At the highest concentration of tested extract, the result showed 2.3, 2.0 and 1.8 folds higher inhibitory effect against HCT116, HT29 and Caco-2 respectively when compared to normal cell line. This result has demonstrated that MUM256 extract was selectively cytotoxic towards colon cancer cell lines. In order