Putting Ug99 on the map: An update on current and future monitoring

DEFF Research Database (Denmark)

Hodson, D P; Nazari, K; Park, R F

2011-01-01

Detection of stem rust race TTKSK (Ug99) from Uganda in 1998/99 highlighted not only the extremely high vulnerability of the global wheat crop to stem rust but also a lack of adequate global systems to monitor such a threat. Progress in the development and expansion of the Global Cereal Rust...... Monitoring System (GCRMS) is described. The current situation regarding the Ug99 lineage of races is outlined and the potential for expansion into important wheat areas is considered. The GCRMS has successfully tracked the spread and changes that are occurring within the Ug99 lineage and is now well...... capacity for race analysis is seen to be critical and integration of the Global Rust Reference Centre into the stem rust monitoring network is seen as a positive development. The current acute situation with severe epidemics of stripe rust in many countries indicates a clear need for more effective global...

Oil spill in the Rio de la Plata estuary, Argentina: 1. Biogeochemical assessment of waters, sediments, soils and biota

International Nuclear Information System (INIS)

Colombo, J.C.; Barreda, A.; Bilos, C.; Cappelletti, N.; Demichelis, S.; Lombardi, P.; Migoya, M.C.; Skorupka, C.; Suarez, G.

2005-01-01

Aliphatic (ALI) and aromatic (ARO) hydrocarbon concentrations, composition and sources were evaluated in waters, sediments, soils and biota to assess the impact of ∼1000 tons of oil spilled in Rio de la Plata coastal waters. Total ALI levels ranged from 0.4-262 μg/l in waters, 0.01-87 μg/g in sediments, 5-39 μg/g in bivalves, 12-323 μg/g in macrophytes to 948-5187 μg/g in soils. ARO varied from non-detected 10 μg/l, 0.01-1.3 μg/g, 1.0-16 μg/g, 0.5-6.9 μg/g to 22-67 μg/g, respectively. Offshore (1, 5, 15 km) waters and sediments were little affected and contained low background hydrocarbon levels reflecting an effective wind-driven transport of the slick to the coast. Six months after the spill, coastal waters, sediments, soils and biota still presented very high levels exceeding baseline concentrations by 1-3 orders of magnitude. UCM/resolved aliphatic ratio showed a clear trend of increasing decay: coastal waters (3.3) n-C23) and petrogenic/pyrogenic relationship (methylated/unsubstitued PAH) discriminated the samples according to the different degree of impact. The following paper present the results of the study of the progress of hydrocarbon disappearance in sediments and soils 13 and 42 months after the spill. - The Oil spill impact the Rio de la Plata was evaluated by HRGC and multivariate techniques applied to waters, sediments and biota

Rachunek kosztów działańjako podstawa wyceny usług

Directory of Open Access Journals (Sweden)

Gertruda Krystyna Świderska

2009-03-01

Full Text Available Artykuł prezentuje wykorzystanie rachunku kosztów działań do wyceny usług na trzech rynkach podlegających centralnym regulacjom – rynku usług pocztowych, telekomunikacyjnych oraz świadczeń zdrowotnych. Doświadczenia krajów Unii Europejskiej (w tym Polski pokazują nowe obszary wykorzystania rachunku kosztów działań. Potwierdzają, że zastosowanie tego narzędzia pozwala na kontrolę kosztów ponoszonych przy świadczeniu usług oraz wycenę na podstawie rzeczywistego rachunku ekonomicznego. Takie podejście gwarantuje przejrzystość procesu wyceny na rynkach, na których odgrywa to szczególnie istotną rolę. W części pierwszej przedstawiono zarys koncepcji rachunku kosztów działań wykorzystanej w PPUP Poczta Polska. Scharakteryzowano zastosowane rozwiązanie dostosowane do specyfiki działań poczty, zawierające elementy obiektowego rachunku kosztów działań oraz rachunku kosztów działań sterowanego czasem. W części drugiej zaprezentowano zastosowanie koncepcji rachunku kosztów działań do wyceny świadczonych usług w British Telecom. Wykorzystanie właściwych nośników kosztów pozwala na prawidłowe przypisanie kosztów obiektom je generującym. W części trzeciej opisano doświadczenia krajów Unii Europejskiej w zakresie stosowania rachunku kosztów działań do wyceny świadczeń medycznych. Stanowią one przesłankę dla wdrożenia tej koncepcji do wyceny usług zdrowotnych na rynku polskim.

Toxicity of lead-contaminated sediment to mallards

Science.gov (United States)

Heinz, G.H.; Hoffman, D.J.; Sileo, L.; Audet, D.J.; LeCaptain, L.J.

1999-01-01

Because consumption of lead-contaminated sediment has been suspected as the cause of waterfowl mortality in the Coeur d?Alene River basin in Idaho, we studied the bioavailability and toxicity of this sediment to mallards (Anas platyrhynchos). In experiment 1, one of 10 adult male mallards died when fed a pelleted commercial duck diet that contained 24% lead-contaminated sediment (with 3,400 μg/g lead in the sediment). Protoporphyrin levels in the blood increased as the percentage of lead-contaminated sediment in the diet increased. Birds fed 24% lead-contaminated sediment exhibited atrophy of the breast muscles, green staining of the feathers around the vent, viscous bile, green staining of the gizzard lining, and renal tubular intranuclear inclusion bodies. Mallards fed 24% lead-contaminated sediment had means of 6.1 μg/g of lead in the blood and 28 μg/g in the liver (wet-weight basis) and 1,660 μg/g in the feces (dry-weight basis). In experiment 2, we raised the dietary concentration of the lead-contaminated sediment to 48%, but only about 20% sediment was actually ingested due to food washing by the birds. Protoporphyrin levels were elevated in the lead-exposed birds, and all of the mallards fed 48% lead-contaminated sediment had renal tubular intranuclear inclusion bodies. The concentrations of lead in the liver were 9.1 μg/g for mallards fed 24% lead-contaminated sediment and 16 μg/g for mallards fed 48% lead-contaminated sediment. In experiment 3, four of five mallards died when fed a ground corn diet containing 24% lead-contaminated sediment (with 4,000 μg/g lead in this sample of sediment), but none died when the 24% lead-contaminated sediment was mixed into a nutritionally balanced commercial duck diet; estimated actual ingestion rates for sediment were 14% and 17% for the corn and commercial diets. Lead exposure caused elevations in protoporphyrin, and four of the five mallards fed 24% lead-contaminated sediment in a commercial diet and all five

Study of the sediment contamination levels in a mangrove swamp polluted by a marine oil spill

Energy Technology Data Exchange (ETDEWEB)

Wong, T.W.Y.; Ke, L.; Wong, Y.S.; Tam, N.F.Y. [City University of Hong Kong, Hong Kong SAR (China)

2002-07-01

The pattern of oil retention in mangrove sediments was studied in an effort to determine the temporal changes of petroleum hydrocarbon concentrations and composition several months after oil spills occur. Mangroves are inter-tidal wetlands in tropical and subtropical coastlines. Due to the anoxic and water logging characteristics of mangrove sediments, oil residues linger much longer in these wetlands compared to other coastal habitats. In November 2000, an accidental oil spill occurred in the Pearl River Estuary in which approximately 230,000 litres of crude oil was leaked from an oil tanker. The spilled oil migrated to the YiO, a typical mangrove swamp in Hong Kong Special Administrative Region. The degree of oil contamination in the sediments depended on the sediment texture and topography of the mangrove. The total petroleum hydrocarbon (TPH) concentration of the sediments in the most affected area near a freshwater creek flowing into the sea was 130 times higher than normal, one month after the accident. The mean TPH concentration was 2862 ug/g of dry sediment while the mean carbon preference index was 1.22 compared to the background value of 3.97. The temporal changes of the petroleum hydrocarbon level in 5 defined areas were examined for 7 months after the spill. The most polluted area next to the creek was determined to have very high TPH levels in the muddy sediments even 7 months after the spill. Oil residues infiltrated as deep as 20 cm into the sediments, making it more difficult to degrade than surface pollution and posing long-term adverse effects on trees in the area. It was determined that with growing industrialization and increasing demands for fuel and energy supply, mangroves in South China should be ranked as top priority for protection from oil spills. 19 refs., 6 tabs., 6 figs.

Study of the sediment contamination levels in a mangrove swamp polluted by a marine oil spill

International Nuclear Information System (INIS)

Wong, T.W.Y.; Ke, L.; Wong, Y.S.; Tam, N.F.Y.

2002-01-01

The pattern of oil retention in mangrove sediments was studied in an effort to determine the temporal changes of petroleum hydrocarbon concentrations and composition several months after oil spills occur. Mangroves are inter-tidal wetlands in tropical and subtropical coastlines. Due to the anoxic and water logging characteristics of mangrove sediments, oil residues linger much longer in these wetlands compared to other coastal habitats. In November 2000, an accidental oil spill occurred in the Pearl River Estuary in which approximately 230,000 litres of crude oil was leaked from an oil tanker. The spilled oil migrated to the YiO, a typical mangrove swamp in Hong Kong Special Administrative Region. The degree of oil contamination in the sediments depended on the sediment texture and topography of the mangrove. The total petroleum hydrocarbon (TPH) concentration of the sediments in the most affected area near a freshwater creek flowing into the sea was 130 times higher than normal, one month after the accident. The mean TPH concentration was 2862 ug/g of dry sediment while the mean carbon preference index was 1.22 compared to the background value of 3.97. The temporal changes of the petroleum hydrocarbon level in 5 defined areas were examined for 7 months after the spill. The most polluted area next to the creek was determined to have very high TPH levels in the muddy sediments even 7 months after the spill. Oil residues infiltrated as deep as 20 cm into the sediments, making it more difficult to degrade than surface pollution and posing long-term adverse effects on trees in the area. It was determined that with growing industrialization and increasing demands for fuel and energy supply, mangroves in South China should be ranked as top priority for protection from oil spills. 19 refs., 6 tabs., 6 figs

Site-specific sediment clean-up objectives developed by the sediment quality triad

International Nuclear Information System (INIS)

Redman, S.; Janisch, T.

1995-01-01

Sediment chemistry, sediment toxicity, and benthic macroinvertebrate community data were collected and evaluated in concert (1) to characterize adverse effects of hydrocarbon and metal contaminants in the sediments of a small inlet of Superior Bay, Lake Superior and a tributary creek and (2) to derive numeric objectives for the clean up of this system. Sediments from reference locations and eight study sites were analyzed for a range of contaminants, including hydrocarbons (measured both as diesel range organics (DRO) and oil and grease), lead, chromium, and ammonia. A range of sediment toxicity was observed across the eight study sites using a variety of tests and endpoints: Hyalella azteca (10 day survival and growth), Chironomus tentans (10 day survival and growth), Ceriodaphnia dubia (48 hour survival), and Daphnia magna (48 hour survival and 10 day survival and reproduction). A range of alterations of the benthic macroinvertebrate community compared with communities from reference locations were observed. Benthic community alterations were summarized quantitatively by taxa richness and Shannon-Weiner mean diversity. Lowest effect levels determined through this study included 150 microg/g dry sediment for DRO (as measured in this study) and 40 microg/g dry sediment for lead. Effects thresholds determined through this study included 1,500 microg/g dry sediment for DRO and 90 microg/g dry sediment for lead. These levels and concentrations measured in relevant reference locations are being used to define objectives for sediment clean up in the inlet and creek

Commentary: "An Evaluation of Universal Grammar and the Phonological Mind"-UG Is Still a Viable Hypothesis.

Science.gov (United States)

Berent, Iris

2016-01-01

Everett (2016b) criticizes The Phonological Mind thesis (Berent, 2013a,b) on logical, methodological and empirical grounds. Most of Everett's concerns are directed toward the hypothesis that the phonological grammar is constrained by universal grammatical (UG) principles. Contrary to Everett's logical challenges, here I show that the UG hypothesis is readily falsifiable, that universality is not inconsistent with innateness (Everett's arguments to the contrary are rooted in a basic confusion of the UG phenotype and the genotype), and that its empirical evaluation does not require a full evolutionary account of language. A detailed analysis of one case study, the syllable hierarchy, presents a specific demonstration that people have knowledge of putatively universal principles that are unattested in their language and these principles are most likely linguistic in nature. Whether Universal Grammar exists remains unknown, but Everett's arguments hardly undermine the viability of this hypothesis.

Atrazine degradation by bioaugmented sediment from constructed wetlands.

Science.gov (United States)

Runes, H B; Jenkins, J J; Bottomley, P J

2001-10-01

The potential to establish pesticide biodegradation in constructed wetland sediment was investigated. Under microcosm conditions, bioaugmentation of sediment with small quantities of an atrazine spill-site soil (1:100 w/w) resulted in the mineralization of 25-30% of 14C ethyl atrazine (1-10 microg g(-1) sediment) as 14CO2 under both unsaturated and water-saturated conditions; atrazine and its common metabolites were almost undetectable after 30 days incubation. By comparison, unbioaugmented sediment supplemented with organic amendments (cellulose or cattail leaves) mineralized only 2-3% of 14C ethyl atrazine, and extractable atrazine and its common metabolites comprised approximately 70% of the original application. The population density of atrazine-degrading microorganisms in unbioaugmented sediment was increased from approximately 10(2)/g to 10(4)/g by bioaugmentation (1:100 w/w), and increased by another 60-fold (6.0x10(5) g(-1)) after incubation with 10 microg g(-1) of atrazine. A high population of atrazine degraders (approximately 10(6) g(-1)) and enhanced rates of atrazine mineralization also developed in bioaugmented sediment after incubation in flooded mesocosms planted with cattails (Typha latifolia) and supplemented with atrazine (3.2 mg l(-1), 1 microg g(-1) sediment). In the absence of atrazine, neither the population of atrazine degraders, nor the atrazine mineralizing potential of bioaugmented sediment increased, regardless of the presence or absence of cattails. Bioaugmentation might be a simple method to promote pesticide degradation in nursery run-off channeled through constructed wetlands, if persistence of degraders in the absence of pesticide is not a serious constraint.

Discovery of a Novel Stem Rust Resistance Allele in Durum Wheat that Exhibits Differential Reactions to Ug99 Isolates

Directory of Open Access Journals (Sweden)

Jayaveeramuthu Nirmala

2017-10-01

Full Text Available Wheat stem rust, caused by Puccinia graminis f. sp. tritici Eriks. & E. Henn, can incur yield losses in susceptible cultivars of durum wheat, Triticum turgidum ssp. durum (Desf. Husnot. Although several durum cultivars possess the stem rust resistance gene Sr13, additional genes in durum wheat effective against emerging virulent races have not been described. Durum line 8155-B1 confers resistance against the P. graminis f. sp. tritici race TTKST, the variant race of the Ug99 race group with additional virulence to wheat stem rust resistance gene Sr24. However, 8155-B1 does not confer resistance to the first-described race in the Ug99 race group: TTKSK. We mapped a single gene conferring resistance in 8155-B1 against race TTKST, Sr8155B1, to chromosome arm 6AS by utilizing Rusty/8155-B1 and Rusty*2/8155-B1 populations and the 90K Infinium iSelect Custom bead chip supplemented by KASP assays. One marker, KASP_6AS_IWB10558, cosegregated with Sr8155B1 in both populations and correctly predicted Sr8155B1 presence or absence in 11 durum cultivars tested. We confirmed the presence of Sr8155B1 in cultivar Mountrail by mapping in the population Choteau/Mountrail. The marker developed in this study could be used to predict the presence of resistance to race TTKST in uncharacterized durum breeding lines, and also to combine Sr8155B1 with resistance genes effective to Ug99 such as Sr13. The map location of Sr8155B1 cannot rule out the possibility that this gene is an allele at the Sr8 locus. However, race specificity indicates that Sr8155B1 is different from the known alleles Sr8a and Sr8b.

report general | 1-Overview | 5-Publications | Indian Academy of ...

Indian Academy of Sciences (India)

In this process, the advantages offered by distance education methods should also be exploited. ... The U.G. course should be solid and broad based, providing a good ... Thus all U.G. students should take some common courses in physics, ...

Application of organic-geochemistry, coal-petrology and isotope-geochemistry to facies-analysis and hydrocarbon exploration in the NE-Paris Basin (Trias-Lias Luxemburg)

International Nuclear Information System (INIS)

Flekken, P.M.

1978-01-01

Triassic and Liassic sediments of NE-Paris Basin (Luxemburg) were investigated by organic-geochemical, coal petrographical and isotope-geochemical methods. The objective was to characterize the stratigraphic stages and to investigate the facies relations between them with a view to possible hydrocarbon exploration. The sediments contain an average of 3.1% organic carbon, 413 ug/g extractable organic matter (bitumen) and 0.65% insoluble, isolatable organic particles which constitute part of the kerogen. The non-isolatable kerogen is 2.4% of the whole rock. (orig./BR) [de

Purification of Giardia muris cysts by velocity sedimentation.

OpenAIRE

Sauch, J F

1984-01-01

Giardia muris cysts were separated from fecal contaminants in primary isolates by unit gravity velocity sedimentation. Crude isolates obtained by centrifugation over 1.0 M sucrose were overlaid onto a Percoll density gradient, 1.01 to 1.03 g/ml. G. muris cysts were well separated from faster-sedimenting fecal debris and slower-sedimenting Spironucleus muris and bacteria in 1.5 h.

Atomic absorption spectrophotometric determination of microgram levels of Co, Ni, Cu, Pb, and Zn in soil and sediment extracts containing large amounts of Mn and Fe

Science.gov (United States)

Chao, T.T.; Sanzolone, R.F.

1973-01-01

An atomic absorption spectrophotometric method has been developed for the determination of seven metal ions in the hydroxylamine extract of soils and sediments. Mn, Fe, and Zn are directly determined in the aqueous extract upon dilution. Co, Ni, Cu, and Pb in a separate aliquot of the extract are chelated with APDC (ammonium pyrrolidine dithiocarbamate) and extracted into MIBK (methyl isobutyl ketone) before determination. Data are presented to show the quantitative recovery of microgram levels of Co, Ni, Cu, and Pb by APDC-MIBK chelation-extraction from synthetic solutions containing as much as 2,000 ug/ml (micrograms per milliliter) Mn or 50 ug/ml Fe. Recovery of known amounts of the metal ions from sample solutions is equally satisfactory. Reproducible results are obtained by replicate analyses of two sediment samples for the seven metals.

An investigation into breast imaging as part of the undergraduate (UG) education of diagnostic radiography students in the UK

International Nuclear Information System (INIS)

Strudwick, R.M.; Taylor, K.

2017-01-01

Introduction: How mammography is incorporated into undergraduate (UG) radiography training may influence student perception of the speciality and its potential as a future career option. An overview is provided of the academic and clinical content of UG radiography courses relating to mammography across the UK. Methods: Using mixed methods and an iterative, inductive approach supplying quantitative and qualitative data, we identify any variations and discuss possible causes which may help influence future training strategies. A self-designed questionnaire containing open and closed questions was sent online using SurveyMonkey™ to course leaders of all Higher Education Institutions (HEIs) offering BSc (Hons) Diagnostic Radiography courses in the UK. Responses were analysed for trends which were further explored by semi structured telephone interviews. These were transcribed and evaluated using a thematic analysis, the themes being categorised and coded. Results: 19 of 24 (79%) HEIs responded to the questionnaire. Follow up telephone interviews were conducted with five course leaders to further explore themes. Academic teaching ranged from 3 to 25 h over the 3 year course. Compared to other specialities 10 (53%) HEIs spent less time on mammography with 12 (63%) citing HCPC standards as the reason. 11 (65%) HEIs sent students on mammography placements, 2 (12%) sent females only. Placement times ranged between 2 days and 2 weeks. Influences included availability of expert teaching and relationship with clinical departments. Conclusion: There is variation in undergraduate exposure to mammography. Students views should be sought to add validity to these findings - Highlights: • A summary of undergraduate (UG) breast imaging in the UK. • Themes around the delivery of UG breast imaging education in university and practice. • Opinions of UG course leaders and other stakeholders about UG breast imaging education. • There is a variation across UK universities in

Commentary: “An Evaluation of Universal Grammar and the Phonological Mind”—UG Is Still a Viable Hypothesis

Science.gov (United States)

Berent, Iris

2016-01-01

Everett (2016b) criticizes The Phonological Mind thesis (Berent, 2013a,b) on logical, methodological and empirical grounds. Most of Everett’s concerns are directed toward the hypothesis that the phonological grammar is constrained by universal grammatical (UG) principles. Contrary to Everett’s logical challenges, here I show that the UG hypothesis is readily falsifiable, that universality is not inconsistent with innateness (Everett’s arguments to the contrary are rooted in a basic confusion of the UG phenotype and the genotype), and that its empirical evaluation does not require a full evolutionary account of language. A detailed analysis of one case study, the syllable hierarchy, presents a specific demonstration that people have knowledge of putatively universal principles that are unattested in their language and these principles are most likely linguistic in nature. Whether Universal Grammar exists remains unknown, but Everett’s arguments hardly undermine the viability of this hypothesis. PMID:27471480

Purification of Giardia muris cysts by velocity sedimentation.

Science.gov (United States)

Sauch, J F

1984-01-01

Giardia muris cysts were separated from fecal contaminants in primary isolates by unit gravity velocity sedimentation. Crude isolates obtained by centrifugation over 1.0 M sucrose were overlaid onto a Percoll density gradient, 1.01 to 1.03 g/ml. G. muris cysts were well separated from faster-sedimenting fecal debris and slower-sedimenting Spironucleus muris and bacteria in 1.5 h. PMID:6486790

Identification and characterization of Sr13, a tetraploid wheat gene that confers resistance to the Ug99 stem rust race group

Science.gov (United States)

The Puccinia graminis f. sp. tritici (Pgt) Ug99 race group is virulent to most stem rust resistance genes currently deployed in wheat and poses a serious threat to global wheat production. The durum wheat (Triticum turgidum ssp. durum) gene Sr13 confers resistance to Ug99 in addition to virulent rac...

Xylanase production by a local fungal isolate, Aspergillus niger USM AI 1 via solid state

Directory of Open Access Journals (Sweden)

Ibrahim Che Omar

2005-03-01

Full Text Available Isolate USM A1 I which was identified to be Aspergillus niger was selected as a potential producer of xylanase via a solid state fermentation system (SSF using palm kernel cake (PKC as substrate. The modification of the physical conditions of the SSF system indicated that the xylanase activity was 23.97 U/g PKC at the moisture ratio of 1:0.75 of PKC: moistening agent with the inoculum size of 1¥104 spores/ml and cultivated at the ambient temperature (28±3ºC. The supplementation of additional carbon and nitrogen sources in the PKC medium could enhance enzyme productivity. The maximum production of xylanase and growth obtained with the supplementation of xylose at 0.75% (w/w were 25.40 U/g and 1.69 mg glucosamine/ g PKC. Moreover, the presence of NaNO3 at 0.075% (w/w as additional nitrogen source further enhanced xylanase production to 33.99 U/g PKC although the growth remained unchanged at about 1.67 mg glucosa- mine/g PKC. The optimized conditions showed an increased xylanase production by 157% compared to before the optimization of the SSF system. The xylanase productivity was 23.12 U/mg glucosamine after optimization and 11.72 U/mg glucosamine before optimization.

High-temperature vaporization of thorium-uranium mixed monocarbide (Th1-y, Uy)C

International Nuclear Information System (INIS)

Koyama, Tadafumi; Yamawaki, Michio

1989-01-01

Vaporization thermodynamics of thorium-uranium mixed monocarbide phase (Th 1-y , U y )C was studied by mass spectrometric Knudsen effusion method for the compositions of (Th 0.9 , U 0.1 )C 0.855 , (Th 0.8 , U 0.2 )C 0.973 and (Th 0.6 , U 0.4 )C 0.973 . The partial vapor pressures of Th(g) and U(g) and activities of Th and U of these mixed monocarbides were determined at temperatures ranging from about 2000 to 2200 K. Further, the partial pressures of Th(g) and U(g) and activities of Th and U of the stoichiometric mixed monocarbides (Th 1-y , U y )C 1.00 were evaluated by compensating for the effect of carbon content. The Gibbs energies of formation of stoichiometric (Th 1-y , U y )C 1.00 were also evaluated. (orig.)

Radionuclides in sediments from Port Phillip Bay, Australia

International Nuclear Information System (INIS)

Smith, J.D.; Tinker, R.A.; Towler, P.H.

1998-01-01

Full text: Sediment cores were collected from two sites in Port Phillip Bay, Australia, in 1994 and 1995. The concentration of 210 Pb and parameters including water content were measured. The sites chosen were near the centre of the bay where fine sediment accumulates, and towards the northern end of the bay closer to the mouth of the Yarra River. The mid-bay sediment had a high water content (about 1.8 g water per g dry sediment) and a supported 210 Pb activity of about 22 mBq per g of dry sediment. The sediments from further north in the bay were more consolidated, with a lower water content (about 0.6 g water per g dry sediment), and had a supported 210 Pb activity of about 6 mBq per g of dry sediment. Unsupported 210 Pb occurred to depths of about 10 cm in the mid-bay sediment and about 20 cm in sediment from further north in the bay. Models incorporating the water and 210 Pb contents of the sediments were used to calculate possible rates of sediment accumulation and mixing. The distribution of other radionuclides was used as an aid in understanding the sediment behaviour in Port Phillip Bay

Trace metal levels in sediments of Pearl Harbor (Hawaii)

International Nuclear Information System (INIS)

Ashwood, T.L.; Olsen, C.R.; Larsen, I.L.; Tamura, T.

1986-09-01

This study was conducted to measure the distribution of lead and other trace metals in the sediments of Pearl Harbon (Hawaii) to determine whether paint chips from vessels of the US Navy's Inactive Fleet have affected the environmental quality of Middle Loch. Sediment cores (ranging from 0.5 to 3.0 m long) were collected from Middle Loch near the Naval Inactive Ships Maintenance Facility and in an area of West Loch that is relatively isolated and unaffected by naval operations. Concentrations of copper, lead, and zinc averaged 180 μg/g, 49 μg/g, and 272 μg/g, respectively, in recent Middle Loch sediments. These concentrations are significantly higher than those in either historical Middle Loch sediments or recent West Loch sediments. However, except for lead, the concentrations in recent Middle Loch sediments are similar to those of older Middle Loch sediments, which indicates that the increase in trace metal contamination began before the onset of Inactive Fleet operations (about 1946). Increased trace metal levels in recent Middle Loch sediments might be expected to result from two potential sources: (1) sewage discharges and (2) paint from inactive vessels. Since paint contains elevated levels of lead and zinc but little copper, the elevated copper levels in Middle Loch sediments tend to implicate sewage as the source of trace metal contamination. Moreover, the lead:zinc ratio of recent Middle Loch sediments (0.18:1) is a factor of 10 lower than that measured in paint (2.1:1), and the Middle Loch lead:zinc ratio is not significantly greater than that measured in recent West Loch sediments (0.21:1). Hence, we suggest that sewage rather than paint is the major source of trace metal contamination of Middle Loch. This is consistent with the findings of a previous study by US navy personnel

Factors influencing mercury in freshwater surface sediments of northeastern North America

Science.gov (United States)

Kamman, N.C.; Chalmers, A.; Clair, T.A.; Major, A.; Moore, R.B.; Norton, S.A.; Shanley, J.B.

2005-01-01

We report on an inventory and analysis of sediment mercury (Hg) concentrations from 579 sites across northeastern North America. Sediment Hg concentrations ranged from the limit of detection ca. 0.01-3.7 ??g g -1 (dry weight, d.w.), and the average concentration was 0.19 ??g g-1 (d.w.) Sediment methylmercury concentrations ranged from 0.15 to 21 ng g-1 (d.w.) and the mean concentration was 3.83 ng g -1 (d.w.). Total Hg concentrations (HgT) were greatest in lakes > reservoirs > rivers, although the proportion of Hg as methylmercury showed an inverse pattern. Total Hg was weakly and positively correlated with the sediment organic matter and percent of watershed as forested land, and weakly and negatively correlated with sediment solids content, drainage area, and agricultural land. Sediment methylmercury concentrations were weakly and positively correlated to wetland area, and weakly and negatively correlated to drainage area. Methylmercury, expressed as a percentage of HgT was positively correlated to agricultural land area. For sites with co-located sediment and fish-tissue sampling results, there was no relationship between sediment Hg and fish-tissue Hg. Finally, our data indicate that at least 44% of waters across the region have sediment HgT concentrations in excess of Canadian and United States minimum sediment contaminant guidelines for the protection of aquatic biota. ?? 2005 Springer Science+Business Media, Inc.

Sedimentation rates and erosion changes recorded in recent sediments of Lake Piaseczno, south-eastern Poland

Science.gov (United States)

Tylmann, Wojciech; Turczyński, Marek; Kinder, Małgorzata

2009-10-01

This paper presents the dating results and basic analyses of recent sediments from Lake Piaseczno. The age of sediments was determined using the 210Pb method and constant flux: constant sedimentation (CF: CS) model. The estimated timescale was in agreement with the AMS14C date from the base of the core. The mean sediment accumulation rate during the last 100 years was calculated as 0.025 g cm-2 a-1. Based on the radiocarbon date, the rate of sediment accumulation below the 210Pb dating horizon was estimated as 0.066 g cm-2 a-1. The variability of main physical properties and sediment components along the core was analysed as well. The sediments were characterised by a very high water content (>80%). Carbonates were either not present or at a very low level (interesting record of increasing erosion intensity in the catchment area. Analysis of archival cartographic materials demonstrated that the most likely reason for the enhanced transport of minerogenic matter to the lake was deforestation caused by human activity in the beginning of the 20th century.

Effect of biostimulation on the microbial community in PCB-contaminated sediments through periodic amendment of sediment with iron.

Science.gov (United States)

Srinivasa Varadhan, A; Khodadoust, Amid P; Brenner, Richard C

2011-10-01

Reductive dehalogenation of polychlorinated biphenyls (PCBs) by indigenous dehalorespiring microorganisms in contaminated sediments may be enhanced via biostimulation by supplying hydrogen generated through the anaerobic corrosion of elemental iron added to the sediment. In this study, the effect of periodic amendment of sediment with various dosages of iron on the microbial community present in sediment was investigated using phospholipid fatty acid analysis (PLFA) over a period of 18 months. Three PCB-contaminated sediments (two freshwater lake sediments and one marine sediment) were used. Signature biomarker analysis of the microbial community present in all three sediments revealed the enrichment of Dehalococcoides species, the population of which was sustained for a longer period of time when the sediment microcosms were amended with the lower dosage of iron (0.01 g iron per g dry sediment) every 6 months as compared to the blank system (without iron). Lower microbial stress levels were reported for the system periodically amended with 0.01 g of iron per g dry sediment every 6 months, thus reducing the competition from other hydrogen-utilizing microorganisms like methanogens, iron reducers, and sulfate reducers. The concentration of hydrogen in the system was found to be an important factor influencing the shift in microbial communities in all sediments with time. Periodic amendment of sediment with larger dosages of iron every 3 months resulted in the early prevalence of Geobacteraceae and sulfate-reducing bacteria followed by methanogens. An average pH of 8.4 (range of 8.2-8.6) and an average hydrogen concentration of 0.75% (range of 0.3-1.2%) observed between 6 and 15 months of the study were found to be conducive to sustaining the population of Dehalococcoides species in the three sediments amended with 0.01 g iron per g dry sediment. Biostimulation of indigenous PCB dechlorinators by the periodic amendment of contaminated sediments with low dosages of

Corrosion Test Results for Inconel 600 vs Inconel-Stainless UG Bellows

International Nuclear Information System (INIS)

Osborne, P.E.

2002-01-01

The Conversion Project (CP) of the Molten Salt Reactor Experiment at Oak Ridge National Laboratory (ORNL) involves converting slightly less than 40 kg of 233 U to a stable form for safe storage. The operation is performed within a few vessels interconnected by valves and 1/2-in. metal tubing. During this conversion, a particularly toxic and corrosive by-product is formed, namely aqueous hydrofluoric acid (HF). The production of HF is a result of the hydrolysis of UF 6 and subsequent steam treatments of UO 2 F 2 . For each mole of UF 6 converted, 6 mol of HF are produced. The HF that forms during conversion combines with water to produce approximately 1.5 L of 33 wt % HF. As this mixture is transferred within the process system, the tubing and valves are exposed to high concentrations of HF in liquid and vapor form. Of particular concern in the system are the almost 30 valves that have the potential for exposure to HF. For these valves, a vendor-supplied UG valve was installed. UG valves consist of an Alloy 400 (Monel) body and stem tip and Alloy 600 (Inconel) bellows. These valves have been used under experimental conditions that simulate the CP. It has been established that they have a finite life when exposed to a HF and air environment. Most failures were seen around the flange at the bottom of the bellows, and it was suspected that this flange and the weld material were not Inconel. In December 2001, the vendor confirmed that this flange was not Inconel but instead was stainless steel 316. After discussions between the vendor and ORNL staff involved with the CP effort, it was decided that the entire wetted area of the bellows would be fabricated from Alloy 600. In March 2002, four newly fabricated bellows assemblies were received from the vendor for the purposes of corrosion testing in HF. This report presents results from the corrosion tests conducted to determine if the new design of the bellows would enhance their corrosion resistance

Anaerobic denitrification in fungi from the coastal marine sediments off Goa, India

Digital Repository Service at National Institute of Oceanography (India)

Manohar, C.S.; Raghukumar, C.

and 5 applying the formula 3.14* r 2 * h, the total hyphal lengths were expressed as biovolume g -1 dry sediment. The biovolume was converted to biomass using the conversion factor 0.2 g cm -3 (Newell et al. 1986). The C biomass was calculated... in the sediment sections at St-I (A) & St-II (B). Bacterial C data during Oct 2005 and April 2006 is depicted as numbers*10 4 pg C g -1 dry sediments whereas it is numbers * 10 3 pg C g-1 dry sediment during the other sampling periods. Fungal C biomass...

Sediment quality guidelines for copper and zinc for filter-feeding estuarine oysters?

Energy Technology Data Exchange (ETDEWEB)

Birch, G.F., E-mail: gavin.birch@sydney.edu.a [Environmental Geology Group, School of Geosciences, Sydney University, NSW (Australia); Hogg, T.D. [Environmental Geology Group, School of Geosciences, Sydney University, NSW (Australia)

2011-01-15

Sediment quality guidelines (SQGs) assess the ability of bottom sediment to sustain healthy infauna and water quality guidelines (WQGs) provide protection for a designated percentage of aquatic species. Filter-feeding marine species, e.g. oysters and mussels, acquire food from particles in the water column and protection of these animals is not provided by SQGs or WQGs. The current work investigated the relationship between metal (Cu, Zn) concentrations in total and fine-fraction (<62.5 {mu}m) surficial sediment digested in a range of acids and chelating agents and oyster tissue metal concentrations. A strong correlation between oyster tissue Cu and Zn concentrations and fine-fraction surficial sediment digested in 1 M HCl provided a sedimentary guideline which predicted tissue metal concentrations in oysters and established a level (<45 {mu}g g{sup -1} and <1000 {mu}g g{sup -1}, respectively) for protecting oysters from exceeding human consumption levels (70 {mu}g g{sup -1} and 1000 {mu}g g{sup -1}, respectively). - A strong correlation between oyster tissue Cu and Zn concentrations and fine-fraction surficial sediment digested in 1 M HCl provided a sedimentary guideline which predicted tissue metal concentrations in oysters and established a level for protecting oysters from exceeding human consumption levels for these metals. The guidelines for fine surficial sediment developed in the present work accurately predicted oyster tissue concentrations in the field.

Biodegradation of nonylphenol in river sediment

International Nuclear Information System (INIS)

Yuan, S.Y.; Yu, C.H.; Chang, B.V.

2004-01-01

We investigated the biodegradation of nonylphenol monoethoxylate (NP1EO) and nonylphenol (NP) by aerobic microbes in sediment samples collected at four sites along the Erren River in southern Taiwan. Aerobic degradation rate constants (k 1 ) and half-lives (t 1/2 ) for NP (2 μg g -1 ) ranged from 0.007 to 0.051 day -1 and 13.6 to 99.0 days, respectively; for NP1EO (2 μg g -1 ) the ranges were 0.006 to 0.010 day -1 and 69.3 to 115.5 days. Aerobic degradation rates for NP and NP1EO were enhanced by shaking and increased temperature, and delayed by the addition of Pb, Cd, Cu, Zn, phthalic acid esters (PAEs), and NaCl, as well as by reduced levels of ammonium, phosphate, and sulfate. Of the microorganism strains isolated from the sediment samples, we found that strain JC1 (identified as Pseudomonas sp.) expressed the best biodegrading ability. Also noted was the presence of 4'-amino-acetophenone, an intermediate product resulting from the aerobic degradation of NP by Pseudomonas sp. - The effects of manipulating several factors on nonylphenol and nonylphenol monoethoxylate degradation in river sediment were analysed

Quantification of African cassava mosaic virus (ACMV) and East African cassava mosaic virus (EACMV-UG) in single and mixed infected Cassava (Manihot esculenta Crantz) using quantitative PCR.

Science.gov (United States)

Naseem, Saadia; Winter, Stephan

2016-01-01

The quantity of genomic DNA-A and DNA-B of African cassava mosaic virus (ACMV) and East African cassava mosaic virus Uganda (Uganda variant, EACMV-UG) was analysed using quantitative PCR to assess virus concentrations in plants from susceptible and tolerant cultivars. The concentrations of genome components in absolute and relative quantification experiments in single and mixed viral infections were determined. Virus concentration was much higher in symptomatic leaf tissues compared to non-symptomatic leaves and corresponded with the severity of disease symptoms. In general, higher titres were recorded for EACMV-UG Ca055 compared to ACMV DRC6. The quantitative assessment also showed that the distribution of both viruses in the moderately resistant cassava cv. TMS 30572 was not different from the highly susceptible cv. TME 117. Natural mixed infections with both viruses gave severe disease symptoms. Relative quantification of virus genomes in mixed infections showed higher concentrations of EACMV-UG DNA-A compared to ACMV DNA-A, but a marked reduction of EACMV-UG DNA-B. The higher concentrations of EACMV-UG DNA-B compared to EACMV DNA-A accumulation in single infections were consistent. Since DNA-B is implicated in virus cell-to-cell spread and systemic movement, the abundance of the EACMV-UG DNA-B may be an important factor driving cassava mosaic disease epidemic. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of cadmium accumulation from suspended sediments and phytoplankton on the Oyster Saccostrea glomerata

Energy Technology Data Exchange (ETDEWEB)

Schmitz, Helena A.; Maher, William A., E-mail: bill.maher@canberra.edu.au; Taylor, Anne M.; Krikowa, Frank

2015-03-15

Highlights: • Saccostrea glomerata accumulated cadmium from sediments and phytoplankton. • Effects were similar for both pathways. • Antioxidant capacity, lipid peroxidation and lysosomal destabilisation were affected. • Clear exposure–dose–response relationships were demonstrated. - Abstract: Metals are accumulated by filter feeding organisms via water, ingestion of suspended sediments or food. The uptake pathway can affect metal toxicity. Saccostrea glomerata were exposed to cadmium through cadmium-spiked suspended sediments (19 and 93 μg/g dry mass) and cadmium-enriched phytoplankton (1.6–3 μg/g dry mass) and cadmium uptake and effects measured. Oysters accumulated appreciable amounts of cadmium from both low and high cadmium spiked suspended sediment treatments (5.9 ± 0.4 μg/g and 23 ± 2 μg/g respectively compared to controls 0.97 ± 0.05 μg/g dry mass). Only a small amount of cadmium was accumulated by ingestion of cadmium-enriched phytoplankton (1.9 ± 0.1 μg/g compared to controls 1.2 ± 0.1 μg/g). In the cadmium spiked suspended sediment experiments, most cadmium was desorbed from sediments and cadmium concentrations in S. glomerata were significantly related to dissolved cadmium concentrations (4–21 μg/L) in the overlying water. In the phytoplankton feeding experiment cadmium concentrations in overlying water were <0.01 μg/L. In both exposure experiments, cadmium-exposed oysters showed a significant reduction in total antioxidant capacity and significantly increased lipid peroxidation and percentage of destabilised lysosomes. Destabilised lysosomes in the suspended sediments experiments also resulted from stress of exposure to the suspended sediments. The study demonstrated that exposure to cadmium via suspended sediments and to low concentrations of cadmium through the ingestion of phytoplankton, can cause sublethal stress to S. glomerata.

Soft-sediment mullions

Science.gov (United States)

Ortner, Hugo

2015-04-01

In this contribution I describe the appearance, formation and significance of soft-sediment mullions. I use several examples from synorogenic turbidites of the Alps and the Pyrenees to show their appearance in the field. Soft-sediment mullions are elongate, slightly irregular bulges at the base of coarse-grained clastic beds (sand to conglomerate), separated by narrow, elongate flames of fine-grained material (mud) protruding into the coarse-grained bed. Various processes may lead to the formation of such structures: (1) longitudinal furrows parallel to the sediment transport direction may form by spiral motion in flow rolls during sediment transport (Dzulinski, 1966; Dzulinski & Simpson, 1966). (2) Loading combined with downslope movement can produce elongate structures parallelling the dowslope direction (Anketell et al., 1970). (3) Soft-sediment mullions are oriented perpendicular or oblique to the downslope direction, and show evidence of bedding-parallel shortening. Thus, they resemble cuspate-lobate folds or mullions, which are well-known in ductile structural geology (e.g. Urai et al., 2001). Soft-sediment mullions have been observed in two cases: Either bedding-parallel shortening can be achieved by slump processes, or by active tectonic shortening. Slumping is characterized by an alternation of stretching and shortening (e.g. Ortner, 2007; Alsop & Marco 2014), and therefore mullions do overprint or are overprinted by normal faults. In active depositional systems that are subject to tectonic shortening growth strata will form, but sediments already deposited will be shortened during lithification. In some cases, the formation of soft-sediment mullions predates folding, but the most widespread expression of syn-lithification shortening seems to be soft-sediment mullions, that form in the inner arcs of fold hinges. In the examples documented so far, the size of soft-sediment mullions is dependent on the grain-size of the coarse-grained layer, in which the

Distribution of the rare earth elements in the surface sediments from the lower Wuding River of China

International Nuclear Information System (INIS)

Longjiang, M.; Duowen, M.; Ke, H.; Jinghong, Y.

2010-01-01

The abundance and distribution of rare earth elements (REE) and their signatures in the Wuding River of China were studied from samples of surface sediments and related to the geological formation in its watershed. The total REE (ΣREE) average concentrations of the Wuding River sediments (144.56 μg g -1 ), is lower than that in the Yangtze River sediments (167.10 μg g -1 ), getting closer to the values of the Yellow River sediments (137.76 μg g -1 ), being equivalent to the values of the UCC (the upper continental crust) (146.37 μg g-1). The chondrite-normalized REEs indicated LREE enrichment and flat HREE depletion and also showed a slightly negative Eu-anomaly. A similar chondrite-normalized REE distribution pattern between the Wuding River sediments and Yellow River sediments demonstrated the Wuding River sediments are the important material sources of the Yellow River sediments. UCC-normalized REE patterns between the Wuding River sediments and the Yellow River sediments were almost equivalent and close to the UCC. These implied the Wuding River sediments and the Yellow River sediments are subjected mostly to physical weathering due to higher erosion rates. Consequently, they can be used to trace the UCC compositions. (author)

Characteristics of sediment resuspension in Lake Taihu, China: A wave flume study

Science.gov (United States)

Ding, Yanqing; Sun, Limin; Qin, Boqiang; Wu, Tingfeng; Shen, Xia; Wang, Yongping

2018-06-01

Lake Taihu is a typical shallow lake which frequently happens sediment resuspension induced by wind-induced waves. The experiments are carried on to simulate the wave disturbance processes in wave flume by setting a series of wave periods (1.2 s, 1.5 s, 1.8 s) and wave heights (2 cm, 10 cm). It aims to analyze the characteristics of sediment resuspension and the mechanisms of nutrients release and to evaluate the effects of sediment dredging on sediment resuspension and nutrients release in Lake Taihu. The results show that wave shear stress during 2 cm and 10 cm wave height processes ranges 0.018-0.023 N/m2 and 0.221-0.307 N/m2, respectively. Wave shear stress has no significant differences between wave periods. Wave height has much more effects on sediment resuspension. Wave height of 2 cm could induce total suspended solids (TSS) reaching up to 5.21 g/m2 and resuspension flux of sediment (M) up to 1.74 g/m2. TSS sharply increases to 30.33-52.41 g/m2 and M reached up to 48.94 g/m2 when wave height reaches to 10 cm. The disturbance depth under different sediment bulk weights ranges from 0.089 to 0.161 mm. Variation of suspended solids in 3 layers (1 cm, 5 cm, 20 cm above sediment interface) has no significant differences. Organic matter, TN and TP have positive relationship with SS. Organic matter is only accounted for 5.7%-7.3% of SS. The experiments under different sediment bulk densities (1.34 g/cm3, 1.47 g/cm3 and 1.59 g/cm3) find that TSS and M fall by 44.2% and 39.8% with sediment bulk density increasing, respectively. Total TN, DTN, TP and DTP decrease by 24.3%-33.6%. It indicates that sediment dredging could effectively reduce SS concentration and nutrient levels in water column. The researches provide a theoretical basis for sediment dredging to control the shore zone of Lake Taihu for lake management.

Sediment Transport

DEFF Research Database (Denmark)

Liu, Zhou

Flow and sediment transport are important in relation to several engineering topics, e.g. erosion around structures, backfilling of dredged channels and nearshore morphological change. The purpose of the present book is to describe both the basic hydrodynamics and the basic sediment transport...... mechanics. Chapter 1 deals with fundamentals in fluid mechanics with emphasis on bed shear stress by currents, while chapter 3 discusses wave boundary layer theory. They are both written with a view to sediment transport. Sediment transport in rivers, cross-shore and longshore are dealt with in chapters 2......, 4 and 5, respectively. It is not the intention of the book to give a broad review of the literature on this very wide topic. The book tries to pick up information which is of engineering importance. An obstacle to the study of sedimentation is the scale effect in model tests. Whenever small...

Reconstructing Eolian Delivery to the Ulleung Basin (IODP Site U1430) Over the Past 12 Myr

Science.gov (United States)

Anderson, C. H.; Dunlea, A. G.; Murray, R. W.; Tada, R.; Alvarez Zarikian, C. A.

2017-12-01

Spring storms associated with the seasonal phases of the East Asian Monsoon (EAM), transport dust seaward and influence marine sedimentation in adjacent ocean regions. Here, we aim to track changes in the intensity of the EAM since the late Miocene by examining the relative proportions and sources of eolian inputs in marine sediment records. We use bulk sediment recovered from Site U1430 in the Ulleung Basin during Integrated Ocean Drilling Program Expedition 346 in 2013 to examine changes in the EAM over the past 12 Myr. Sediment recovered at this site is clayey silt, nannofossil and diatom oozes, claystone, and basal glauonitic sandstone. We analyze major, trace, and rare earth element concentrations for 72 bulk sediment samples analyzed by ICP-ES and ICP-MS, and interpret this dataset using a variety of multivariate statistical partitioning techniques (Q-mode Factor Analyses (QFA), Multiple Linear Regressions) to investigate sediment provenance. Sedimentologic observations and elemental concentrations indicate the presence of biogenic siliceous and carbonaceous components mixed with aluminosilicates. For example, Si/Al (g/g) reaches local maxima at 3 Ma and 10 Ma in several diatom rich sections, and Ca/Al (g/g) exhibits a peak at 0.58 Ma. Other downhole element ratios exhibit subtle variations, including Ti/Al of 0.05 +/- 0.004 g/g, Sc/Al 2 +/- 0.2 ug/g, and Rb/Al 17 +/- 1.5 ug/g. When plotted in ternary diagrams, samples exhibit offset arrays (La-Th-Sc) or multiple clusters (Zr-Nb-Sc) from an Upper Continental Crust and Mid-Ocean Ridge Basalt mixing line. In Th-Cr-Nb, the data exhibit a V-shaped array. The range of geochemical variability suggests that multiple sources of terrigenous matter and/or volcanic ash are being delivered to the site. The multivariate statistics also indicate the mixing of multiple aluminosilicate sources. Focusing on a suite of seven elements (Al, Ti, Sc, Cr, Rb, Th, La), preliminary QFA suggest that five factors are required to

Corrosion Test Results for Inconel 600 vs Inconel-Stainless UG Bellows

Energy Technology Data Exchange (ETDEWEB)

Osborne, P.E.

2002-09-11

The Conversion Project (CP) of the Molten Salt Reactor Experiment at Oak Ridge National Laboratory (ORNL) involves converting slightly less than 40 kg of {sup 233}U to a stable form for safe storage. The operation is performed within a few vessels interconnected by valves and 1/2-in. metal tubing. During this conversion, a particularly toxic and corrosive by-product is formed, namely aqueous hydrofluoric acid (HF). The production of HF is a result of the hydrolysis of UF{sub 6} and subsequent steam treatments of UO{sub 2}F{sub 2}. For each mole of UF{sub 6} converted, 6 mol of HF are produced. The HF that forms during conversion combines with water to produce approximately 1.5 L of 33 wt % HF. As this mixture is transferred within the process system, the tubing and valves are exposed to high concentrations of HF in liquid and vapor form. Of particular concern in the system are the almost 30 valves that have the potential for exposure to HF. For these valves, a vendor-supplied UG valve was installed. UG valves consist of an Alloy 400 (Monel) body and stem tip and Alloy 600 (Inconel) bellows. These valves have been used under experimental conditions that simulate the CP. It has been established that they have a finite life when exposed to a HF and air environment. Most failures were seen around the flange at the bottom of the bellows, and it was suspected that this flange and the weld material were not Inconel. In December 2001, the vendor confirmed that this flange was not Inconel but instead was stainless steel 316. After discussions between the vendor and ORNL staff involved with the CP effort, it was decided that the entire wetted area of the bellows would be fabricated from Alloy 600. In March 2002, four newly fabricated bellows assemblies were received from the vendor for the purposes of corrosion testing in HF. This report presents results from the corrosion tests conducted to determine if the new design of the bellows would enhance their corrosion resistance.

210Pb and Mass Flux Imbalance Between the Settling Particulates and Sediments at a Sediment Trap

Science.gov (United States)

Wu, C.; Chung, Y.; Hung, G.

2005-05-01

In order to evaluate the mass balance problems between the settling particulates and the underlying sediments, sediment traps were deployed at M1 site (21o32¡¦N, 119o28¡¦E; 2948m) where a box core was taken recently. The sediment trap results were previously published (Chung et al., 2004: Continental Shelf Research). We report here the 210Pb profile measured on this box core by determining its daughter, 210Po, with alpha spectrometry, assuming the paired nuclides are in radioactive equilibrium. The box core (33 cm long, taken in June, 2004) was analyzed for the distributions of its water content, loss on ignition (LOI), and 210Pb. The water content decreases with depth and averages about 55 percent; the LOI as a measure of the total organic matter (TOM) is fairly constant at about 12 percent. The 210Pb profile shows a general exponential decrease with depth, yielding a maximum sedimentation rate of 0.26cm/y, applying a constant flux and constant sedimentation rate model. This rate translates to a mass flux of 0.31g/cm2/y or about 8.5g/m2/d with a dry bulk density of 1.2g/cm3. Based on the excess 210Pb inventory integrated over the core length, the 210Pb flux is estimated at about 19.2dpm/cm2/y or 526dpm/cm2/d assuming at steady state. The 210Pb and mass fluxes obtained from the deepest trap at M1 were only 129dpm/m2/d and 0.55g/m2/d, respectively. The large ¡excess¡" of the 210Pb and mass fluxes in the sediments over those measured from the sediment trap (4 times in 210Pb flux and 14 times in mass flux) suggests either the sedimentation rate was overestimated due to neglect of the mixing effect, and/or large additional particulates, as resuspended sediments which contain less 210Pb, have been transported laterally near the bottom from elsewhere.

Pb’s high sedimentation inside the bay mouth of Jiaozhou Bay

Science.gov (United States)

Yang, Dongfang; Miao, Zhenqing; Huang, Xinmin; Wei, Linzhen; Feng, Ming

2017-12-01

Sedimentation is one of the key environmental behaviors of pollutants in the ocean. This paper analyzed the seasonal and temporal variations of Pb’s sedimentation process in Jiaozhou Bay in 1987. Results showed that Pb contents in bottom waters in Jiaozhou Bay in May, July and November 1987 were 1.87-2.60 μg L-1, 15.11-19.68 μg L-1 and 11.08-15.18 μg L-1, and the pollution levels of Pb in May, July and November 1987 were slight, heavy and heavy, respectively. In May 1987, there was low sedimentation process in waters in the outside of the bay mouth, yet were high sedimentation process in waters in the middle and inside of the bay mouth. In July and November 1987, there was low sedimentation process in waters in the outside of the bay mouth, yet were high sedimentation process in waters in the inside of the bay mouth. The seasonal-temporal variation of sedimentation processes of Pb were determined by the variations of sources input and the vertical water’s effect.

Sr and Pb isotopic composition of five USGS glasses (BHVO-2G, BIR-1G, BCR-2G, TB-1G, NKT-1G)

NARCIS (Netherlands)

Elburg, M.A.; Vroon, P.Z.; van der Wagt, R.A.C.A.; Tchalikian, A.

2005-01-01

Sr isotopic compositions and Rb/Sr ratios of three USGS glasses (BHVO-2G, BIR-1G, BCR-2G) are identical to those of the original USGS reference materials. NKT-1G and TB-1G give values of 0.70351 and 0.70558, respectively. Pb isotopic ratios were measured by the standard-sample bracketing technique

Organochlorinated pesticides in sediments from the Lake Albufera of Valencia (Spain).

Science.gov (United States)

Peris, E; Requena, S; de la Guardia, M; Pastor, A; Carrasco, J M

2005-09-01

Bottom sediment samples from 121 sites of the Lake Albufera of Valencia were analyzed. Dieldrin, endrin, heptachlor and op'-DDT were not detected (<0.01 ng g(-1)) in 88-93% of the sites. Aldrin and HCB concentration ranges were between <0.01 and 0.1 ng g(-1) in 86% and 94% of the sites, respectively. Heptachlor-epoxide and lindane 95% confidence intervals were 0.2-0.5 and 0.06-0.12, respectively. The greatest average concentration corresponds to pp'-DDE, pp'-DDD and pp'-DDT. The sum of six isomers and derivatives of the DDT average concentration reaches 2.1 ng g(-1), as opposed to 2.7 ng g(-1) for the sum of 13 pesticides considered. In the site with a major contamination, 27.0 ng g(-1) of pp'-DDD and 12.8 ng g(-1) of pp'-DDT were accumulated. The DDE:DDT proportion average was 0.37, indicating an aged DDT contamination. Concentrations of pesticides in sediments were compared to three sediment quality guidelines, and indicated that a low biological effects level can be expected in either sediments or aquatic organisms.

Dating of sediments and determination of sedimentation rate. Proceedings

Energy Technology Data Exchange (ETDEWEB)

Illus, E [ed.

1998-08-01

The Second NKS (Nordic Nuclear Safety Research)/EKO-1 Seminar was held at the Finnish Centre for Radiation and Nuclear Safety (STUK) on April 2-3, 1997. The work of the NKS is based on 4-year programmes; the current programme having been planned for the years 1994-1997. The programme comprises 3 major fields, one of them being environmental effects (EKO). Under this umbrella there are 4 main projects. The EKO-1 project deals with marine radioecology, in particular bottom sediments and sediment processes. The programme of the second seminar consisted of 8 invited lecturers and 6 other scientific presentations. Dating of sediments and determination of sedimentation rate are important in all types of sedimentological study and model calculations of fluxes of substances in the aquatic environment. In many cases these tasks have been closely related to radioecological studies undertaken in marine and fresh water environments, because they are often based on measured depth profiles of certain natural or artificial radionuclides present in the sediments. During recent decades Pb-210 has proved to be very useful in dating of sediments, but some other radionuclides have also been successfully used, e.g. Pu-239,240, Am-241 and Cs-137. The difficulties existing and problems involved in dating of sediments, as well as solutions for resolving these problems are discussed in the presentations

Dating of sediments and determination of sedimentation rate. Proceedings

International Nuclear Information System (INIS)

Illus, E.

1998-01-01

The Second NKS (Nordic Nuclear Safety Research)/EKO-1 Seminar was held at the Finnish Centre for Radiation and Nuclear Safety (STUK) on April 2-3, 1997. The work of the NKS is based on 4-year programmes; the current programme having been planned for the years 1994-1997. The programme comprises 3 major fields, one of them being environmental effects (EKO). Under this umbrella there are 4 main projects. The EKO-1 project deals with marine radioecology, in particular bottom sediments and sediment processes. The programme of the second seminar consisted of 8 invited lecturers and 6 other scientific presentations. Dating of sediments and determination of sedimentation rate are important in all types of sedimentological study and model calculations of fluxes of substances in the aquatic environment. In many cases these tasks have been closely related to radioecological studies undertaken in marine and fresh water environments, because they are often based on measured depth profiles of certain natural or artificial radionuclides present in the sediments. During recent decades Pb-210 has proved to be very useful in dating of sediments, but some other radionuclides have also been successfully used, e.g. Pu-239,240, Am-241 and Cs-137. The difficulties existing and problems involved in dating of sediments, as well as solutions for resolving these problems are discussed in the presentations

Anthropogenic lead concentrations and sources in Baltic Sea sediments based on lead isotopic composition

International Nuclear Information System (INIS)

Zaborska, Agata

2014-01-01

Highlights: • Pb concentrations reach even 147 μg/g at Gdansk Basin sediments. • Marine sediments deposited before 1860 are not contaminated by Pb. • Contemporary inventories of anthropogenic Pb in marine sediments was of 0.5–11 g for m 2 . • The lowest 206 Pb/ 207 Pb (1.165) were measured in sediments deposited between 1970s–90s. • Coal burning was always the most important Pb source in Poland. - Abstract: The Gulf of Gdańsk is influenced by heavy metals of anthropogenic origin. In this study, temporal concentration changes of Pb, Zn, Cd, and Cu were studied in six, 50 cm long sediment cores. The main aim of the study was to concentrate on the history of Pb fluxes and Pb isotopic composition ( 206 Pb/ 207 Pb and 208 Pb/ 206 Pb) to trace Pb sources. The lowest Pb concentrations (19 μg g −1 ) were measured in sediments deposited circa 1860, while the highest Pb concentrations (63–147 μg g −1 ) were measured in sediments deposited between 1960s and 70s. Pre-industrial Pb fluxes were 7 Pb m 2 year −1 , while after WWII they reached 199 Pb m 2 year −1 . Highest 206 Pb/ 207 Pb ratios (∼1.22) were measured in the oldest sediment layers, and the lowest 206 Pb/ 207 Pb ratios (∼1.165) were measured in the sediments deposited in 1970s–90s. During the period of highest Pb contamination, the anthropogenic Pb fraction reached up to 93%. A general discussion of the Pb sources, emissions, and loads for Poland is included

[Characteristics of organic carbon forms in the sediment of Wuliangsuhai and Daihai Lakes].

Science.gov (United States)

Mao, Hai-Fang; He, Jiang; Lü, Chang-Wei; Liang, Ying; Liu, Hua-Lin; Wang, Feng-Jiao

2011-03-01

The characteristics and differences of organic carbon forms in the sediments of the Wuliangsuhai and the Daihai Lakes with different eutrophication types were discussed in the present study. The results showed that the range of total organic carbon content (TOC) in Wuliangsuhai Lake was 4.50-22.83 g x kg(-1) with the average of 11.80 g x kg(-1). The range of heavy-fraction organic carbon content was 3.38-21.67 g x kg(-1) with the average of 10.76 g x kg(-1). The range of light-fraction organic carbon content was 0.46-1.80 g x kg(-1) with the average of 1.04 g x kg(-1); The range of ROC content was 0.62-3.64 g x kg(-1) with the average of 2.11 g x kg(-1), while the range of total organic carbon content in Daihai lake was 6.84-23.46 g x kg(-1) with the average of 14.94 g x kg(-1). The range of heavy-fraction organic carbon content was 5.27-22.23 g x kg(-1) with the average of 13.89 g x kg(-1). The range of light-fraction organic carbon content was 0.76-1.57 g x kg(-1). The range of ROC content was 1.54-7.08 g x kg(-1) with the average of 3.62 g x kg(-1). The results indicated that the heavy-fraction organic carbon was the major component of the organic carbon and plays an important role in the accumulation of organic carbon in the sediments of two Lakes. The content of light-fraction organic carbon was similar in the sediments of two lakes, whereas, the contents of total organic carbon and heavy-fraction organic carbon in the sediment of Wuliangsuhai Lake were less than those in the sediment of Daihai Lake, and the value of LFOC/TOC in the Wuliangsuhai Lake was larger than that in the Daihai Lake. The humin was the dominant component of the sediment humus, followed by fulvic acid in the two lakes. The values of HM/HS in the sediments of Wuliangsuhai lake range from 43.06% to 77.25% with the average of 62.15% and values of HM/HS in the sediments of Dahai lake range from 49.23% to 73.85% with the average of 65.30%. The tightly combined humus was the dominant form in

Targeted introgression of stem rust Ug99 resistance from wheatgrasses into pasta and bread wheat

Science.gov (United States)

In the past 50 years, a number of stem rust resistance (Sr) genes have been transferred from several wheat-related grasses into durum (i.e. pasta) and bread wheat through chromosome translocations and additions. To utilize these genes for controlling the Ug99 races of the stem rust pathogen, we ini...

Concentrations of organotin compounds in sediment and clams collected from coastal areas in Vietnam

International Nuclear Information System (INIS)

Midorikawa, Sayaka; Arai, Takaomi; Harino, Hiroya; Ohji, Madoka; Nguyen Duc Cu; Miyazaki, Nobuyuki

2004-01-01

Levels of butyltin (BT) and phenyltin (PT) compounds were determined in sediments and clam Meretrix spp. collected from north and central coastal areas in Vietnam. Concentrations of TBT in sediments ranged from 0.89 to 34 ng g -1 dry wt and those in clams ranged from 1.4 to 56 ng g -1 wet wt. The levels of TBT in sediments and clams from Vietnam were within limits reported from other countries. Further, the TBT level in clams was lower than the tolerable average residue level (TARL) estimated based on tolerable daily intake (TDI). Trace amounts of PTs were also found in both sediment and clam samples. In sediments from north and central Vietnam, the concentrations of TBT were highest in the order of Hue (28 ng g -1 dry wt), Cua Luc (15 ng g -1 dry wt), Sam Son (6.3 ng g -1 dry wt), and Tra Co (5.5 ng g -1 dry wt). Among the clams from north and central Vietnam, the levels of TBT in clams from Cua Luc were dramatically high at 47 ng g -1 wet wt. TBT formed the principal butyltin species in sediment at all sites studied. The ratios of TBT in sediment were higher among BT compounds at all study sites. Of total BTs, TBT was the dominant species in clams from almost all sites studied. In spatial distribution, TPT showed a pattern similar to TBT, suggesting the use of TPT as an antifouling paint. The partition coefficient between sediment and calms was calculated. The partition coefficients of TBT and TPT were 2.01 (0.56-5.5) and 9.23 (3.1-20), respectively. These results show that sediment-bound TBT is a source of contamination to clams in addition to dissolved TBT

Sediment isotope tomography (SIT) model version 1

International Nuclear Information System (INIS)

Carroll, J.; Abraham, J.D.

1996-01-01

Geochronology using 210 Pb is the principal method used to quantify sediment accumulation in rapidly depositing aquatic environments such as lakes, estuaries, continental shelves, and submarine canyons. This method is based on the radioactive decay of 210 Pb with depth in a column of sediment. The decay through time of 210 Pb P(t) is governed by the exponential law P(t) = P 0 exp( -λt) where P 0 is the surficial concentration at time t = 0, and λ is the decay constant (3.114 sm-bullet 10 -2 year [yr] -1 for 210 Pb). If the sedimentation rate is constant, then elapsed time t is connected to burial depth x, through x = Vt where V is the sedimentation velocity. Accordingly, P(x) = P 0 exp( -λx/V). The sedimentation velocity is obtained from an exponential fit to the measured 210 Pb data P(x), with depth x

Textural properties of low-fat set-type yoghurt depending on mTG addition

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Lívia Darnay

2016-07-01

Full Text Available Our aim was to determine how 0.5-2 U/g non-inactivated mTG affects the pH development and apparent viscosity during fermentation. Furthermore we wished to examine how the enzyme addition could change protein structure, gel strength and sensory characteristics by healthy low-fat set-type yoghurt product. Therefore commercial mTG enzyme preparation was added in different concentrations (0.5-2.0 U/g, in 0.5 U/g steps to 1.5 % bovine milk simultaneously with DVS starter culture. Our study revealed that enzyme dosage (0.5-2 U/g protein had no impact on pH development and apparent viscosity during fermentation when manufacturing low-fat (1.5 % set-type yoghurt. The addition of mTG contributed to 38 % more whey retention with incorporation of β-casein, and caused 44 % higher gel strength up to a level of 1 U/g protein.

Geochemical partitioning of lead in biogenic carbonate sediments in a coral reef depositional environment

International Nuclear Information System (INIS)

Horta-Puga, Guillermo

2017-01-01

The fate of trace elements in reef depositional environments has not been extensively investigated. The aim of this study was to determine the partitioning of Pb in sediments of the Veracruz Reef System, and its relation to local environmental sources. Lead was determined in four geochemical fractions: exchangeable (3.8 ± 0.4 μg g −1 ), carbonate (57.0 ± 13.6 μg g −1 ), organic matter (2.0 ± 0.9 μg g −1 ), and mineral (17.5 ± 5.4 μg g −1 ). For the mineral fraction, lead concentrations were higher in those reefs influenced by river discharge or by long-distance transport of terrigenous sediments. The bioavailable concentration of lead (range: 21.9–85.6 μg g −1 ) indicates that the Veracruz Reef System is a moderately polluted area. As expected, the carbonate fraction contained the highest proportion of Pb (70%), and because the reef framework is largely made up of by biogenic carbonate sediments, hence, it is therefore the most important repository of Pb in coral reef depositional environments. - Highlights: • Lead concentrations were determined in four geochemical fractions of reef sediments. • The carbonate fraction accounted for > 70% of the content of Pb in reef sediments. • Terrigenous sediments are the main source of Pb associated to the mineral fraction. • The Veracruz Reef System is considered a moderately polluted area. • Sediments are the main repositories of lead in coral reef depositional environments.

210Pb and 137Cs dating of sediments from Zigetang Lake, Tibetan Plateau

International Nuclear Information System (INIS)

Yao, S.C.; Li, S.J.; Zhang, H.C.

2008-01-01

Zigetang Lake located in the central Tibetan Plateau was selected for the purpose of understanding of recent sedimentation rates. Based on 137 Cs dating marker, the sediment rate was 0.077 cm x yr -1 . The sedimentation rate was calculated to be 0.071 cm x yr -1 and 0.029 g x cm -2 x yr -1 on the basis of 210 Pb CIC model. 210 Pb CRS model was also used for understanding of recent sedimentation change. The sediment accumulation rates for the CRS model ranged from 0.022 to 0.038 g x cm -2 x yr -1 with an irregular high value of 0.12 g x cm -2 x yr -1 around 1932 at Zigetang Lake core in the past eighty years. (author)

Global Distribution of Net Electron Acceptance in Subseafloor Sediment

Science.gov (United States)

Fulfer, V. M.; Pockalny, R. A.; D'Hondt, S.

2017-12-01

We quantified the global distribution of net electron acceptance rates (e-/m2/year) in subseafloor sediment (>1.5 meters below seafloor [mbsf]) using (i) a modified version of the chemical-reaction-rate algorithm by Wang et al. (2008), (ii) physical properties and dissolved oxygen and sulfate data from interstitial waters of sediment cores collected by the Ocean Drilling Program, Integrated Ocean Drilling Program, International Ocean Discovery Program, and U.S. coring expeditions, and (iii) correlation of net electron acceptance rates to global oceanographic properties. Calculated net rates vary from 4.8 x 1019 e-/m2/year for slowly accumulating abyssal clay to 1.2 x 1023 e-/m2/year for regions of high sedimentation rate. Net electron acceptance rate correlates strongly with mean sedimentation rate. Where sedimentation rate is very low (e.g., 1 m/Myr), dissolved oxygen penetrates more than 70 mbsf and is the primary terminal electron acceptor. Where sedimentation rate is moderate (e.g., 3 to 60 m/Myr), dissolved sulfate penetrates as far as 700 mbsf and is the principal terminal electron acceptor. Where sedimentation rate is high (e.g., > 60 m/Myr), dissolved sulfate penetrates only meters, but is the principal terminal electron acceptor in subseafloor sediment to the depth of sulfate penetration. Because microbial metabolism continues at greater depths than the depth of sulfate penetration in fast-accumulating sediment, complete quantification of subseafloor metabolic rates will require consideration of other chemical species.

Sediment quality guidelines for copper and zinc for filter-feeding estuarine oysters?

International Nuclear Information System (INIS)

Birch, G.F.; Hogg, T.D.

2011-01-01

Sediment quality guidelines (SQGs) assess the ability of bottom sediment to sustain healthy infauna and water quality guidelines (WQGs) provide protection for a designated percentage of aquatic species. Filter-feeding marine species, e.g. oysters and mussels, acquire food from particles in the water column and protection of these animals is not provided by SQGs or WQGs. The current work investigated the relationship between metal (Cu, Zn) concentrations in total and fine-fraction ( -1 and -1 , respectively) for protecting oysters from exceeding human consumption levels (70 μg g -1 and 1000 μg g -1 , respectively). - A strong correlation between oyster tissue Cu and Zn concentrations and fine-fraction surficial sediment digested in 1 M HCl provided a sedimentary guideline which predicted tissue metal concentrations in oysters and established a level for protecting oysters from exceeding human consumption levels for these metals. The guidelines for fine surficial sediment developed in the present work accurately predicted oyster tissue concentrations in the field.

Metal pollution and ecological risk assessment in marine sediments of Karachi Coast, Pakistan.

Science.gov (United States)

Mashiatullah, Azhar; Chaudhary, Muhammad Zaman; Ahmad, Nasir; Javed, Tariq; Ghaffar, Abdul

2013-02-01

Concentrations of 12 metals (Fe, Mn, Cr, Mo, Ni, Pb, Se, Sr, U, V, Zn, and Zr) in surface sediments of Karachi Coast, Pakistan were determined to evaluate their distribution and pollution assessment. The measured metals in the sediments were found to be in the range of Fe, 0.84-6.96 %; Mn, 300-1,300 μg/g; Cr, 12.0-319.84 μg/g; Mo, 0.49-2.03 μg/g; Ni, 1.53-58.86 μg/g; Pb, 9.0-49.46 μg/g; Se, 0.25-.86 μg/g; Sr, 192-1185 μg/g; U, 0.19-1.66 μg/g; V, 15.80-118.20 μg/g; Zn, 15.60-666.28 μg/g; and Zr, 44.02-175.26 μg/g. The mean contents of the metal studied were: Fe, 3.07 %, Mn, 0.05 %; Cr, 96.75 μg/g; Mo, 1.34 μg/g; Ni, 31.39 μg/g; Pb, 23.24 μg/g; Se, 0.61 μg/g; Sr, 374.83 μg/g; U, 0.64 μg/g; V, 61.75 μg/g; Zn, 204.75 μg/g; and Zr:76.27 μg/g, and arrangement of the metals from higher to lower mean content in this area is: Fe > Zn > Mn > Sr > Zn > Cr > Zr > V > Ni > Pb > Mo > U > Se. There is no significant correlation among most of these metals, indicating different anthropogenic and natural sources. To assess ecotoxic potential of marine sediments, Numerical Sediment Quality Guidelines were also applied. The concentration of Pb in all the sediments except one was lower than the threshold effect concentration (TECs) showing that there are no harmful effects to marine life from Pb. On the other hand, the concentrations of Cr, Ni, and Zn exceeded TEC in three stations, indicating their potential risk. The degree of pollution in sediments for metals was assessed by calculating enrichment factor (EF) and pollution load index (PLI). The results indicated that sediments of Layari River Mouth Area, Fish Harbour, and KPT Boat Building Area are highly enriched with Cr and Zn (EF > 5). Sediments of Layari River Outfall Zone were moderately enriched with Ni and Pb (EF > 2). The pollution load index was found in the range of 0.98 to 1.34. Lower values of PLI (≤ 1) at most of sampling locations imply no appreciable input from anthropogenic sources. However

Microbial degradation of petroleum hydrocarbons in estuarine sediment of Tama River in Tokyo urban area

International Nuclear Information System (INIS)

Yamane, Akiko; Hosomi, Masaaki; Murakami, Akihiko; Sakakibara, Koji

1997-01-01

Aerobic and anaerobic biodegradation rates of petroleum hydrocarbons, i.e., hexadecane (HEX), phenanthrene (PHE), and anthracene (ANT), were determined in estuarine sediment of the Tama River in urban Tokyo, followed by estimating their respective degradation potential. While in a sediment slurry, the aerobic biodegradation rates of these petroleum hydrocarbons ranged from 40 to 70 μg.g -1 dry sediment:day -1 . The anaerobic biodegradation rate of HEX was found to be 5 -8 μg.g -1 dry sediment.day -1 , whereas that of PHE and ANT could not be detected following a 2-month incubation. Aerobic degradation of HEX was not affected by coexistence with either PHE or ANT, nor by the salinity level. The number of HEX-, PHE-, or ANT-utilizing bacteria ranged from 5 - 10% of the total number of aerobic heterotrophic bacteria. We calculated their biodegradation potentials using the biomass of naturally existing petroleum hydrocarbon utilizing bacteria present in the sampled sediment, with results for HEX, PHE, and ANT being 1.0 -3.5, 4.2 x 10 -2 , and 1.2 x 10 -2 -9.4 x 10 -1 μg.g -1 dry sediment day -1 , respectively. In the aerobic tidal sediment of the Tama River, the purification potentials of HEX, PHE, and ANT were assessed to be approximately equal to their accumulation potentials occurring at the normal water level. (Author)

Toxicity of sediments and pore water from Brunswick Estuary, Georgia

Science.gov (United States)

Winger, Parley V.; Lasier, Peter J.; Geitner, Harvey

1993-01-01

A chlor-alkali plant in Brunswick, Georgia, USA, discharged >2 kg mercury/d into a tributary of the Turtle River-Brunswick Estuary from 1966 to 1971. Mercury concentrations in sediments collected in 1989 along the tributary near the chlor-alkali plant ranged from 1 to 27 μg/g (dry weight), with the highest concentrations found in surface (0–8 cm) sediments of subtidal zones in the vicinity of the discharge site. Toxicity screening in 1990 using Microtox® bioassays on pore water extracted on site from sediments collected at six stations distributed along the tributary indicated that pore water was highly toxic near the plant discharge. Ten-day toxicity tests on pore water from subsequent sediment samples collected near the plant discharge confirmed high toxicity to Hyalella azteca, and feeding activity was significantly reduced in whole-sediment tests. In addition to mercury in the sediments, other metals (chromium, lead, and zinc) exceeded 50 μg/g, and polychlorobiphenyl (PCB) concentrations ranged from 67 to 95 μg/g. On a molar basis, acid-volatile sulfide concentrations (20–45 μmol/g) in the sediments exceeded the metal concentrations. Because acid-volatile sulfides bind with cationic metals and form metal sulfides, which are generally not bioavailable, toxicities shown by these sediments were attributed to the high concentrations of PCBs and possibly methylmercury.

Ultrasound assisted mercury extraction from soil and sediment

International Nuclear Information System (INIS)

Collasiol, Andre; Pozebon, Dirce; Maia, Sandra M.

2004-01-01

A method for mercury (Hg) determination in soil, river sediment and marine sediment without sample digestion is investigated. Mercury determination is performed by cold vapour atomic absorption spectrometry (CV-AAS) using a flow injection system. Mercury quantitatively leaches out from the investigated marine sediment into 30% (v/v) HNO 3 assisted by ultrasonic irradiation (during 90-120 s) when sample particles size are ≤120 μm. Similar conditions can be applied for Hg determination in river sediment and soil, excepting the time of sonication which needs to be increased to 180 s and KCl is also added to the extraction medium. The presence of 0.15% (m/v) KCl in addition to 30% (v/v) HNO 3 is seen to be effective for quantitative Hg leaching. The certified samples PACS-2 and MESS-3 (both marine sediment from NRCC), Buffalo River (NIST 8704), Montana Soil (NIST 2710) and the non-certified river sediment sample RS-3 were analysed. The attained results were well within the 95% confidence level of the certificate or close to information value. Samples were analysed using aqueous standard calibration. A characteristic mass of 25 pg, a LOD (3s) of 0.2 μg Hg l -1 and a LOQ (10s) of 0.012 μg Hg g -1 are typically attained. These are based on 800 μl of sample solution and 1.000 g of sample mass in 20 ml. The RSD of 10 consecutive runs of the sample is <5%. The proposed method was finally applied for the determination of Hg in real samples of soil, river sediment and marine sediment. The same samples were also analysed using a digestion method giving similar results

Chronic toxicity of nickel-spiked freshwater sediments: variation in toxicity among eight invertebrate taxa and eight sediments

Science.gov (United States)

Besser, John M.; Brumbaugh, William G.; Ingersoll, Christopher G.; Ivey, Chris D.; Kunz, James L.; Kemble, Nile E.; Schlekat, Christian E.; Garman, Emily R.

2013-01-01

This study evaluated the chronic toxicity of Ni-spiked freshwater sediments to benthic invertebrates. A 2-step spiking procedure (spiking and sediment dilution) and a 2-stage equilibration period (10 wk anaerobic and 1 wk aerobic) were used to spike 8 freshwater sediments with wide ranges of acid-volatile sulfide (AVS; 0.94–38 µmol/g) and total organic carbon (TOC; 0.42–10%). Chronic sediment toxicity tests were conducted with 8 invertebrates (Hyalella azteca, Gammarus pseudolimnaeus, Chironomus riparius, Chironomus dilutus, Hexagenia sp., Lumbriculus variegatus, Tubifex tubifex, and Lampsilis siliquoidea) in 2 spiked sediments. Nickel toxicity thresholds estimated from species-sensitivity distributions were 97 µg/g and 752 µg/g (total recoverable Ni; dry wt basis) for sediments with low and high concentrations of AVS and TOC, respectively. Sensitive species were tested with 6 additional sediments. The 20% effect concentrations (EC20s) for Hyalella and Gammarus, but not Hexagenia, were consistent with US Environmental Protection Agency benchmarks based on Ni in porewater and in simultaneously extracted metals (SEM) normalized to AVS and TOC. For Hexagenia, sediment EC20s increased at less than an equimolar basis with increased AVS, and toxicity occurred in several sediments with Ni concentrations in SEM less than AVS. The authors hypothesize that circulation of oxygenated water by Hexagenia led to oxidation of AVS in burrows, creating microenvironments with high Ni exposure. Despite these unexpected results, a strong relationship between Hexagenia EC20s and AVS could provide a basis for conservative site-specific sediment quality guidelines for Ni.

Perfluoroalkyl and polyfluoroalkyl substances in sediments from South Bohai coastal watersheds, China

International Nuclear Information System (INIS)

Zhu, Zhaoyun; Wang, Tieyu; Wang, Pei; Lu, Yonglong; Giesy, John P.

2014-01-01

Highlights: • Relatively high concentrations of PFAS, especially PFOA, were found in the Xiaoqing River sediment. • PFOA and PFBS were the dominant PFAS in the sediments from coastal and riverine area, respectively. • Concentrations of PFNA, PFDA and PFHxS in sediment were significantly correlated with concentrations of organic carbon. • Risks posed by PFOA and PFOS to benthic organisms from concentrations of PFAS in sediments were small. - Abstract: This study investigated the concentrations and distribution of Perfluoroalkyl and polyfluoroalkyl substances (PFAS) in sediments of 12 rivers from South Bohai coastal watersheds. The highest concentrations of ΣPFAS (31.920 ng g −1 dw) and PFOA (29.021 ng g −1 dw) were found in sediments from the Xiaoqing River, which was indicative of local point sources in this region. As for other rivers, concentrations of ΣPFAS ranged from 0.218 to 1.583 ng g −1 dw were found in the coastal sediments and from 0.167 to 1.953 ng g −1 dw in the riverine sediments. Predominant PFAS from coastal and riverine areas were PFOA and PFBS, with percentages of 30% and 35%, respectively. Partitioning analysis showed the concentrations of PFNA, PFDA and PFHxS were significantly correlated with organic carbon. The results of a preliminary environmental hazard assessment showed that PFOS posed the highest hazard in the Mi River, while PFOA posed a relative higher hazard in the Xiaoqing River

Year 3 Summary Report: Baseline Selenium Monitoring of Agricultural Drains Operated by the Imperial Irrigation District in the Salton Sea Basin

Science.gov (United States)

Saiki, Michael K.; Martin, Barbara A.; May, Thomas W.

2008-01-01

This report summarizes findings from the third year of a 4-year-long field investigation to document selected baseline environmental conditions in 29 agricultural drains and ponds operated by the Imperial Irrigation District along the southern border of the Salton Sea. Routine water quality and fish species were measured at roughly quarterly intervals from April 2007 to January 2008. The water quality measurements included total suspended solids and total (particulate plus dissolved) selenium. In addition, during April and October 2007, water samples were collected from seven intensively monitored drains for measurement of particulate and dissolved selenium, including inorganic and organic fractions. In addition, sediment, aquatic food chain matrices (particulate organic detritus, filamentous algae, net plankton, and midge [chironomid] larvae), and two fish species (western mosquitofish, Gambusia affinis; and sailfin molly, Poecilia latipinna) were sampled from the seven drains for measurement of total selenium concentrations. The mosquitofish and mollies were intended to serve as surrogates for desert pupfish (Cyprinodon macularius), an endangered species that we were not permitted to take for selenium determinations. Water quality values were typical of surface waters in a hot desert climate. A few drains exhibited brackish, near anoxic conditions especially during the summer and fall when water temperatures occasionally exceeded 30 degrees C. In general, total selenium concentrations in water varied directly with conductivity and inversely with pH. Although desert pupfish were found in several drains, sometimes in relatively high numbers, the fish faunas of most drains and ponds were dominated by nonnative species, especially red shiner (Cyprinella lutrensis), mosquitofish, and mollies. Dissolved selenium in water samples from the seven intensively monitored drains ranged from 0.700 to 24.1 ug/L, with selenate as the major constituent in all samples. Selenium

The strongest magnetic barrier in the DIII-D tokamak and comparison with the ASDEX UG

Science.gov (United States)

Ali, Halima; Punjabi, Alkesh

2013-05-01

Magnetic perturbations in tokamaks lead to the formation of magnetic islands, chaotic field lines, and the destruction of flux surfaces. Controlling or reducing transport along chaotic field lines is a key challenge in magnetically confined fusion plasmas. A local control method was proposed by Chandre et al. [Nucl. Fusion 46, 33-45 (2006)] to build barriers to magnetic field line diffusion by addition of a small second-order control term localized in the phase space to the field line Hamiltonian. Formation and existence of such magnetic barriers in Ohmically heated tokamaks (OHT), ASDEX UG and piecewise analytic DIII-D [Luxon, J.L.; Davis, L.E., Fusion Technol. 8, 441 (1985)] plasma equilibria was predicted by the authors [Ali, H.; Punjabi, A., Plasma Phys. Control. Fusion 49, 1565-1582 (2007)]. Very recently, this prediction for the DIII-D has been corroborated [Volpe, F.A., et al., Nucl. Fusion 52, 054017 (2012)] by field-line tracing calculations, using experimentally constrained Equilibrium Fit (EFIT) [Lao, et al., Nucl. Fusion 25, 1611 (1985)] DIII-D equilibria perturbed to include the vacuum field from the internal coils utilized in the experiments. This second-order approach is applied to the DIII-D tokamak to build noble irrational magnetic barriers inside the chaos created by the locked resonant magnetic perturbations (RMPs) (m, n)=(3, 1)+(4, 1), with m and n the poloidal and toroidal mode numbers of the Fourier expansion of the magnetic perturbation with amplitude δ. A piecewise, analytic, accurate, axisymmetric generating function for the trajectories of magnetic field lines in the DIII-D is constructed in magnetic coordinates from the experimental EFIT Grad-Shafranov solver [Lao, L, et al., Fusion Sci. Technol. 48, 968 (2005)] for the shot 115,467 at 3000 ms in the DIII-D. A symplectic mathematical map is used to integrate field lines in the DIII-D. A numerical algorithm [Ali, H., et al., Radiat. Eff. Def. Solids Inc. Plasma Sc. Plasma Tech. 165, 83

Persistence of 14C maneb in lettuce plants an soil

International Nuclear Information System (INIS)

Bennaceur, M.; Sennaoui, Z.; Meguenni, H.

1992-10-01

Maneb residue is studied on lettuce plant and soil after spraying on greenhouse with 14C maneb. The residues declined with time. After 37 days from the application, 14C maneb residues in water extracts declined to 1,5. 10-2ug/g from 5,8. 10-1ug/g of the zero day sample in lettuce plants and 4,6. 10-3ug/g from 1,73. 10-1ug/g in soil. The 14C internals residues in lettuce and soil increase respectively till 16 days and 24 days, then decrease to 88% and 4,05% after 37 days. ETU was present in lettuce plant after 8 days then decreases with time. Two metabolites were identified by TLC (EU,ETU)

Agrochemical residues in rivers sediments, Poas, Costa Rica

International Nuclear Information System (INIS)

Masis, Federico; Valdez, Juan; Leon, Sandra; Coto, Tatiana

2008-01-01

The organophosphorus and organochlorine agrochemical residues distribution in sediments of 3 rivers located in an ornamental plant production area were analyzed in Poas canton, Alajuela, Costa Rica. The study comprised 8 months in order to assure 3 seasonal episodes: dry, transitional, and rainy seasons. Sediments were taken in 10 sampling stations along the rivers and characterized by a determination of their organic matter and texture. In 7 out of 10 sampling stations pesticide residues were detected in at least 1 of 4 samplings, but quantified only in 4 stations. Agrochemical residues evaluated included 21 organophosphorus and organochlorine pesticides; however, we found residues of only 3 organochlorine pesticides, due their high persistence in the sediment. Residues corresponded to PCNB (80-800 μg.kg -1 ), Endosulfan-β (40-50 μg.kg -1 ), and Endosulfan-α (90 μg.kg -1 ). Chlorothalonil was detected in only one sample. (author) [es

Optimization of extraction parameters for recovery of a-amylase from the fermented bran of Bacillus circulans GRS313

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Palit Soumen

2001-01-01

Full Text Available The extraction of alpha-amylase in the solid state fermentation of wheat bran by Bacillus circulans GRS313 was optimized. Among various solvents tested, maximum extraction was achieved when 2.5% (v/v glycerol was added. The optimum conditions for extraction were 2.5 hrs soaking time at 30° C under recirculation and agitated condition, which yielded 590 U/g bran of enzyme activity. Whereas under stationary soaking condition the activity of the enzyme was 439.58U/g bran. With repeated wash under the above optimum conditions showed that 600 U/g and 184.2 U/g of enzyme extracted in the 1st and 2nd washes respectively and only 36.84 U/g was recovered in the 3rd wash

Environmental and occupational exposures to mercury among indigenous people in Dunkwa-On-Offin, a small scale gold mining area in the South-West of Ghana.

Science.gov (United States)

Kwaansa-Ansah, E E; Basu, N; Nriagu, J O

2010-11-01

Total mercury concentrations in human hair and urine samples were determined to ascertain the extent of environmental and occupational mercury exposure in Dunkwa-On-Offin, a small scale gold mining area of the central-west region of Ghana. In all ninety-four (94) hair and urine samples comprising of forty (40) small scale miners and fifty-four (54) farmers were collected and analyzed for their total mercury levels using the cold vapour atomic absorption spectrometry. The hair total mercury concentrations ranged from 0.63 to 7.19 ug/g with a mean of 2.35 ± 1.58 ug/g for the farmers and 0.57-6.07 ug/g with a mean of 2.14 ± 1.53 ug/g for the small scale gold miners. There was no significant correlation between the total mercury concentration and the average weekly fish diet. The total mercury concentrations in urine of the miners were higher than those of the farmers and ranged from 0.32 to 3.62 ug/L with a mean of 1.23 ± 0.86 ug/L. The urine concentrations of farmers ranged from 0.075 to 2.31 ug/L with a mean of 0.69 ± 0.39 ug/L. Although the results indicate elevated internal dose of mercury the current levels of exposures do not appear to pose a significant health threat to the people.

Organic carbon accumulation in Brazilian mangal sediments

Science.gov (United States)

Sanders, Christian J.; Smoak, Joseph M.; Sanders, Luciana M.; Sathy Naidu, A.; Patchineelam, Sambasiva R.

2010-12-01

This study reviews the organic carbon (OC) accumulation rates in mangrove forests, margins and intertidal mudflats in geographically distinct areas along the Brazilian coastline (Northeastern to Southern). Our initial results indicate that the mangrove forests in the Northeastern region of Brazil are accumulating more OC (353 g/m 2/y) than in the Southeastern areas (192 g/m 2/y) being that the sediment accumulation rates, 2.8 and 2.5 mm/y, and OC content ˜7.1% and ˜5.8% (dry sediment weight) were contributing factors to the discrepancies between the forests. The intertidal mudflats on the other hand showed substantially greater OC accumulation rates, sedimentation rates and content 1129 g/m 2/y and 234 g/m 2/y; 7.3 and 3.4 mm/y; 10.3% and ˜2.7% (OC of dry sediment weight content), respectively, in the Northeastern compared to the Southeastern region. Mangrove forests in the South-Southeastern regions of Brazil may be more susceptible to the rising sea level, as they are geographically constricted by the vast mountain ranges along the coastline.

Aromatic hydrocarbon concentrations in sediments of Placentia Bay, Newfoundland

International Nuclear Information System (INIS)

Kiceniuk, J.W.

1992-01-01

A study was conducted to examine the potential for contamination of recent sediments with polycyclic aromatic hydrocarbons due to tanker and refinery activity in Placentia Bay, Newfoundland, an area without large local anthropogenic sources of aromatics. Sediment samples were taken from the vicinity of the Come By Chance refinery, Woody Island, Wild Cove, and Port Royal Arm, all in the north end of the bay. The samples were extracted by two methods, dichloromethane extraction of dried sediment for determination of total aromatic hydrocarbon content and hexane extraction of wet sediment for estimation of the bioavailability of hydrocarbons and determination of more volatile compounds. Class analysis of aromatic hydrocarbons was conducted on a NH 2 column with detection at 255 nm. Total concentrations of di-tricyclic aromatics were highest at the Woody Island site (0.6 μg/g). The sediments from the Come By Chance site, Wild Cove, and Port Royal Arm sediments contained 0.3, 0.1, and 0.2 μg/g respectively. The hexane extracts from Come By Chance were lowest in di-tricyclic aromatics (0.007 μg/g), with the other sites being equal in concentration (0.01 μg/g). It is evident from the study that aromatic hydrocarbon concentrations in Placentia Bay are elevated in some parts of the bay in the absence of local combustion sources, and that the most likely source is petroleum. 12 refs., 5 figs., 2 tabs

Resistance to stem rust Ug99 in six bread wheat cultivars maps to chromosome 6DS.

Science.gov (United States)

Lopez-Vera, Eric E; Nelson, Sarah; Singh, Ravi P; Basnet, Bhoja R; Haley, Scott D; Bhavani, Sridhar; Huerta-Espino, Julio; Xoconostle-Cazares, Beatriz G; Ruiz-Medrano, Roberto; Rouse, Matthew N; Singh, Sukhwinder

2014-01-01

Identified SSR markers ( Xcfd49 and Xbarc183 ) linked with stem rust resistance for efficient use in marker-assisted selection and stacking of resistance genes in wheat breeding programs. More than 80 % of the worldwide wheat (Triticum aestivum L.) area is currently sown with varieties susceptible to the Ug99 race group of stem rust fungus. However, wheat lines Niini, Tinkio, Coni, Pfunye, Blouk, and Ripper have demonstrated Ug99 resistance at the seedling and adult plant stages. We mapped stem rust resistance in populations derived from crosses of a susceptible parent with each of the resistant lines. The segregation of resistance in each population indicated the presence of a single gene. The resistance gene in Niini mapped to short arm of chromosome 6D and was flanked by SSR markers Xcfd49 at distances of 3.9 cM proximal and Xbarc183 8.4 cM distal, respectively. The chromosome location of this resistance was validated in three other populations: PBW343/Coni, PBW343/Tinkio, and Cacuke/Pfunye. Resistance initially postulated to be conferred by the SrTmp gene in Blouk and Ripper was also linked to Xcfd49 and Xbarc183 on 6DS, but it was mapped proximal to Xbarc183 at a similar position to previously mapped genes Sr42 and SrCad. Based on the variation in diagnostic marker alleles, it is possible that Niini and Pfunye may carry different resistance genes/alleles. Further studies are needed to determine the allelic relationships between various genes located on chromosome arm 6DS. Our results provide valuable molecular marker and genetic information for developing Ug99 resistant wheat varieties in diverse germplasm and using these markers to tag the resistance genes in wheat breeding.

Acceleration of selenium volatilization in seleniferous agricultural drainage sediments amended with methionine and casein

Energy Technology Data Exchange (ETDEWEB)

Banuelos, G.S. [USDA-ARS, Water Management Research Laboratory, Parlier, CA 93648 (United States)], E-mail: gbanuelos@fresno.ars.usda.gov; Lin, Z.-Q. [Department of Biological Sciences and Environmental Sciences Program, Southern Illinois University Edwardsville, Edwardsville, IL 62026-1651 (United States)

2007-12-15

Phytoremediation is potentially effective for managing excessive selenium (Se) in drainage sediment residing in the San Luis Drain in central California. This 2-year field study examined the feasibility of amending drainage sediment (containing 4.78 {mu}g Se g{sup -1}) with methionine and casein to enhance volatilization without or with vegetation of Sporobolus airoides. Results show that without organic amendments, rates of Se volatilization were less than 25 {mu}g m{sup -2} d{sup -1} in all plots. After amending the sediment with 71.4 mg methionine kg{sup -1} soil, Se volatilization rates were 434 {+-} 107 {mu}g m{sup -2} d{sup -1} in vegetated plots and 289 {+-} 117 {mu}g m{sup -2} d{sup -1} in irrigated bare plots. With the amendment of 572 mg casein kg{sup -1} soil, rates increased to 346 {+-} 103 {mu}g m{sup -2} d{sup -1} in irrigated bare plots and to 114 {+-} 55 {mu}g m{sup -2} d{sup -1} in vegetated plots. Both methionine and casein promoted biological remediation of Se via volatilization most effectively during the warmest months. - Amending drainage sediment with either methionine or casein promotes the volatilization of selenium.

Acceleration of selenium volatilization in seleniferous agricultural drainage sediments amended with methionine and casein

International Nuclear Information System (INIS)

Banuelos, G.S.; Lin, Z.-Q.

2007-01-01

Phytoremediation is potentially effective for managing excessive selenium (Se) in drainage sediment residing in the San Luis Drain in central California. This 2-year field study examined the feasibility of amending drainage sediment (containing 4.78 μg Se g -1 ) with methionine and casein to enhance volatilization without or with vegetation of Sporobolus airoides. Results show that without organic amendments, rates of Se volatilization were less than 25 μg m -2 d -1 in all plots. After amending the sediment with 71.4 mg methionine kg -1 soil, Se volatilization rates were 434 ± 107 μg m -2 d -1 in vegetated plots and 289 ± 117 μg m -2 d -1 in irrigated bare plots. With the amendment of 572 mg casein kg -1 soil, rates increased to 346 ± 103 μg m -2 d -1 in irrigated bare plots and to 114 ± 55 μg m -2 d -1 in vegetated plots. Both methionine and casein promoted biological remediation of Se via volatilization most effectively during the warmest months. - Amending drainage sediment with either methionine or casein promotes the volatilization of selenium

On star-critical and upper size Ramsey numbers

NARCIS (Netherlands)

Zhang, Yanbo; Broersma, Haitze J.; Chen, Yaojun

2016-01-01

In this paper, we study the upper size Ramsey number u(G1,G2)u(G1,G2), defined by Erdős and Faudree, as well as the star-critical Ramsey number r∗(G1,G2)r∗(G1,G2), defined by Hook and Isaak. We define Ramsey-full graphs and size Ramsey good graphs, and perform a detailed study on these graphs. We

Metal concentrations in sediments from tourist beaches of Miri City, Sarawak, Malaysia (Borneo Island).

Science.gov (United States)

Nagarajan, R; Jonathan, M P; Roy, Priyadarsi D; Wai-Hwa, L; Prasanna, M V; Sarkar, S K; Navarrete-López, M

2013-08-15

Forty-three sediment samples were collected from the beaches of Miri City, Sarawak, Malaysia to identify the enrichment of partially leached trace metals (PLTMs) from six different tourist beaches. The samples were analyzed for PLTMs Fe, Mn, Cr, Co, Cu, Ni, Pb, Sr and Zn. The concentration pattern suggest that the southern side of the study area is enriched with Fe (1821-6097 μg g(-1)), Mn (11.57-90.22 μg g(-1)), Cr (51.50-311 μg g(-1)), Ni (18-51 μg g(-1)), Pb (8.81-84.05 μg g(-1)), Sr (25.95-140.49 μg g(-1)) and Zn (12.46-35.04 μg g(-1)). Compared to the eco-toxicological values, Cr>Effects range low (ERL), Lowest effect level (LEL), Severe effect level (SEL); Cu>Unpolluted sediments, ERL, LEL; Pb>Unpolluted sediments and Ni>ERL and LEL. Comparative results with other regions indicate that Co, Cr, Cu, Ni and Zn are higher, indicating an external input rather than natural process. Copyright © 2013 Elsevier Ltd. All rights reserved.

Assessment of sediment quality based on acid-volatile sulfide and simultaneously extracted metals in heavily industrialized area of Asaluyeh, Persian Gulf: concentrations, spatial distributions, and sediment bioavailability/toxicity.

Science.gov (United States)

Arfaeinia, Hossein; Nabipour, Iraj; Ostovar, Afshin; Asadgol, Zahra; Abuee, Ehsan; Keshtkar, Mozhgan; Dobaradaran, Sina

2016-05-01

Sediment samples from the coastal area of Asaluyeh harbor were collected during autumn and spring 2015. The acid-volatile sulfide (AVS) and simultaneously extracted metals (SEMs) were measured to assess the sediment quality and potential ecological risks. The average concentrations (and relative standard deviation (RSD)) of AVS in the industrial sediments were 12.32 μmol/g (36.91) and 6.34 μmol/g (80.05) in autumn and spring, respectively, while in the urban area, these values were 0.44 μmol/g (123.50) and 0.31 μmol/g (160.0) in autumn and spring, respectively. The average concentrations of SEM (and RSD) in the industrial sediments were 15.02 μmol/g (14.38) and 12.34 μmol/g (20.65) in autumn and spring, respectively, while in the urban area, these values were 1.10 μmol/g (43.03) and 1.06 μmol/g (55.59) in autumn and spring, respectively. Zn was the predominant component (34.25-86.24 %) of SEM, while the corresponding value for Cd, much more toxic ingredient, was less than 1 %. Some of the coastal sediments in the harbor of Asaluyeh (20 and 47 % in autumn and spring, respectively) had expected adverse biological effects based on the suggested criterion by United States Environmental Protection Agency (USEPA), while most stations (80 and 53 % in autumn and spring, respectively) had uncertain adverse effects.

Response of Vallisneria natans to Increasing Nitrogen Loading Depends on Sediment Nutrient Characteristics

Directory of Open Access Journals (Sweden)

Jiao Gu

2016-11-01

Full Text Available High nitrogen (N loading may contribute to recession of submerged macrophytes in shallow lakes; yet, its influences vary depending on environmental conditions. In August 2013, we conducted a 28-day factorial-designed field mesocosm experiment in Lake Taihu at the Taihu Laboratory for Lake Ecosystem Research (TLLER to examine the effects of high N loading on the growth of Vallisneria natans in systems with contrasting sediment types. We ran the experiments with two levels of nutrient loading—present-day external nutrient loading (average P: 5 μg·L−1·day−1, N: 130 μg·L−1·day−1 and P: 5 μg·L−1·day−1, and with three times higher N loading (N: 390 μg·L−1·day−1 and used sediment with two contrasting nutrient levels. V. natans growth decreased significantly with increasing N loading, the effect being dependent, however, on the nutrient status of the sediment. In low nutrient sediment, relative growth rates, leaf biomass and root biomass decreased by 11.9%, 18.2% and 23.3%, respectively, at high rather than low N loading, while the decline was larger (44.0%, 32.7% and 41.8%, respectively when using high nutrient sediment. The larger effect in the nutrient-rich sediment may reflect an observed higher shading of phytoplankton and excess nutrient accumulation in plant tissue, though potential toxic effects of the high-nutrient sediment may also have contributed. Our study confirms the occurrence of a negative effect of increasing N loading on submerged plant growth in shallow nutrient-enriched lakes and further shows that this effect is augmented when the plants grow in nutrient-rich sediment. External N control may, therefore, help to protect or restore submerged macrophytes, especially when the sediment is enriched with nutrients and organic matter.

Significance of flow clustering and sequencing on sediment transport: 1D sediment transport modelling

Science.gov (United States)

Hassan, Kazi; Allen, Deonie; Haynes, Heather

2016-04-01

This paper considers 1D hydraulic model data on the effect of high flow clusters and sequencing on sediment transport. Using observed flow gauge data from the River Caldew, England, a novel stochastic modelling approach was developed in order to create alternative 50 year flow sequences. Whilst the observed probability density of gauge data was preserved in all sequences, the order in which those flows occurred was varied using the output from a Hidden Markov Model (HMM) with generalised Pareto distribution (GP). In total, one hundred 50 year synthetic flow series were generated and used as the inflow boundary conditions for individual flow series model runs using the 1D sediment transport model HEC-RAS. The model routed graded sediment through the case study river reach to define the long-term morphological changes. Comparison of individual simulations provided a detailed understanding of the sensitivity of channel capacity to flow sequence. Specifically, each 50 year synthetic flow sequence was analysed using a 3-month, 6-month or 12-month rolling window approach and classified for clusters in peak discharge. As a cluster is described as a temporal grouping of flow events above a specified threshold, the threshold condition used herein is considered as a morphologically active channel forming discharge event. Thus, clusters were identified for peak discharges in excess of 10%, 20%, 50%, 100% and 150% of the 1 year Return Period (RP) event. The window of above-peak flows also required cluster definition and was tested for timeframes 1, 2, 10 and 30 days. Subsequently, clusters could be described in terms of the number of events, maximum peak flow discharge, cumulative flow discharge and skewness (i.e. a description of the flow sequence). The model output for each cluster was analysed for the cumulative flow volume and cumulative sediment transport (mass). This was then compared to the total sediment transport of a single flow event of equivalent flow volume

Sediment accumulation on the Southern California Bight continental margin during the twentieth century

Science.gov (United States)

Alexander, C.R.; Lee, H.J.

2009-01-01

Sediment discharged into the portion of the Southern California Bight extending from Santa Barbara to Dana Point enters a complex system of semi-isolated coastal cells, narrow continental shelves, submarine canyons, and offshore basins. On both the Santa Monica and San Pedro margins, 210Pb accumulation rates decrease in an offshore direction (from ??0.5 g cm-2yr-1 to 0.02 g cm-2yr -1), in concert with a fining in sediment grain size (from 4.5?? to 8.5??), suggesting that offshore transport of wave-resuspended material occurs as relatively dilute nepheloid layers and that hemiplegic sedimentation dominates the supply of sediment to the outer shelf, slope, and basins. Together, these areas are effectively sequestering up to 100% of the annual fluvial input. In contrast to the Santa Monica margin, which does not display evidence of mass wasting as an important process of sediment delivery and redistribution, the San Pedro margin does provide numerous examples of failures and mass wasting, suggesting that intraslope sediment redistribution may play a more important role there. Basin deposits in both areas exhibit evidence of turbidites tentatively associated with both major floods and earthquakes, sourced from either the Redondo Canyon (San Pedro Basin) or Dume Canyon (Santa Monica Basin). On the Palos Verdes shelf, sediment-accumulation rates decrease along and across the shelf away from the White's Point outfall, which has been a major source of contaminants to the shelf deposits. Accumulation rates prior to the construction of the outfall were ??0.2 g cm-2yr-1 and increased 1.5-3.7 times during peak discharges from the outfall in 1971. The distal rate of accumulation has decreased by ??50%, from 0.63 g cm -2yr-1 during the period 1971-1992 to 0.29 g cm -2yr-1 during the period 1992-2003. The proximal rate of accumulation, however, has only decreased ??10%, from 0.83 g cm -2yr-1 during the period 1971-1992 to 0.73 g cm -2yr-1 during the period 1992-2003. Effluent

Assessment of Energetic Compounds, Semi-volatile Organic Compounds, and Trace Elements in Streambed Sediment and Stream Water from Streams Draining Munitions Firing Points and Impact Areas, Fort Riley, Kansas, 2007-08

Science.gov (United States)

Coiner, R.L.; Pope, L.M.; Mehl, H.E.

2010-01-01

An assessment of energetic compounds (explosive and propellant residues) and associated semi-volatile organic compounds (SVOCs) and trace elements in streambed sediment and stream water from streams draining munitions firing points and impact areas at Fort Riley, northeast Kansas, was performed during 2007-08 by the U.S. Geological Survey (USGS) in cooperation with the U.S. Army. Streambed sediment from 16 sampling sites and stream-water samples from 5 sites were collected at or near Fort Riley and analyzed for as many as 17 energetic compounds, 65 SVOCs, and 27 trace elements. None of the energetic compounds or SVOCs were detected in streambed sediment collected from sites within the Fort Riley Military Reservation. This may indicate that these compounds either are not transported from dispersal areas or that analytical methods are not sensitive enough to detect the small concentrations that may be transported. Concentrations of munitions-associated trace elements did not exceed sediment-quality guidelines recommended by the U.S. Environmental Protection Agency (USEPA) and are not indicative of contamination of streambed sediment at selected streambed sampling sites, at least in regards to movement from dispersal areas. Analytical results of stream-water samples provided little evidence of contamination by energetic compounds, SVOCs, or associated trace elements. Perchlorate was detected in 19 of 20 stream-water samples at concentrations ranging from an estimated 0.057 to an estimated 0.236 ug/L (micrograms per liter) with a median concentration of an estimated 0.114 ug/L, substantially less than the USEPA Interim Health Advisory criterion (15 ug/L), and is in the range of documented background concentrations. Because of these small concentrations and possible natural sources (precipitation and groundwater), it is likely that the occurrence of perchlorate in stream water is naturally occurring, although a definitive identification of the source of perchlorate in

Dicty_cDB: Contig-U15201-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available 2e-04 2 ( EX698640 ) GF_AW109651c08 AW1 Schistosoma mansoni cDNA clone... 44 2e-04 2 ( CD147...-0107T-L395-E12-U.B MG1-0107 Schistosoma manso... 44 2e-04 2 ( CD147233 ) ML1-0002T-M131-E11-U.G ML1-0002 Sc

Polycyclic aromatic hydrocarbons (PAHs) in surface sediments of two lakes of the Dongting Lake district in Hunan, China

Science.gov (United States)

He, Jiang; Yang, Yajing; Zhang, Lugang; Luo, Yushuang; Liu, Fei; Yang, Pinhong

2018-04-01

In this paper, 18 and 12 surface sediment samples were collected from Datong Lake and Shanpo Lake, respectively, and the 16 USEPA priority Polycyclic aromatic hydrocarbons (PAHs) in these samples were detected. The result indicated that the Σ16PAHs ranged from 206.56 to 1058.98 ng.g-1 with an average concentration of 667.22 ng.g-1 in sediments from Datong Lake, whereas it ranged from 90.62 to 900.70 ng.g-1 with an average concentration of 364.97 ng.g-1 in sediments from Shanpo Lake. The concentrations of individual PAHs in sediments ranged from 5.50 to 85.23 and from 4.39 to 52.74 ng.g-1 in Datong Lake and Shanpo Lake, respectively. According to the indexes such as HMW/LMW, Ant/(Ant+Phe), Flua/(Flua+Pyr), IcdP/(IcdP+BghiP), and BaA/(BaA+Chr), the PAHs in sediments from both lakes are mainly of pyrogenic origin. The total BaP equivalent in the surface sediment samples from Datong Lake and Shanpo Lake is 42.77 and 33.35 ng.g-1, respectively.

Persistent organic pollutants in soils and sediments from James Ross Island, Antarctica

International Nuclear Information System (INIS)

Klanova, Jana; Matykiewiczova, Nina; Macka, Zdenek; Prosek, Pavel; Laska, Kamil; Klan, Petr

2008-01-01

Soil and sediment samples from James Ross Island were analyzed for their PCB, OCP and PAH contents. Soil concentrations ranged between 0.51 and 1.82 ng g -1 for seven indicator PCB congeners, between 0.49 and 1.34 ng g -1 for HCH congeners, between 0.51 and 3.68 ng g -1 for the sum of p,p'-DDT, DDE, and DDD, and between 34.9 and 171 ng g -1 for the sum of 16 EPA PAHs. Sediment levels from 0.32 to 0.83 ng g -1 were found for PCBs, from 0.14 to 0.76 ng g -1 for HCHs, from 0.19 to 1.15 ng g -1 for DDTs, and from 1.4 to 205 ng g -1 for PAHs. A prevalence of low-mass PAHs, less chlorinated PCBs, and more volatile chemicals indicates that the long-range atmospheric transport from populated areas of Africa, South America, and Australia is the most probable contamination source for the solid matrices in James Ross Island. - A survey of soil, sediment and air contamination in James Ross Island, Antarctica serves as a baseline study for evaluation of an anthropogenic impact of the new research facility

Geochemistry of Fluvial Sediments from Geregu, Southwest Nigeria

Directory of Open Access Journals (Sweden)

Adiotomre Emmanuel E.

2017-03-01

Full Text Available Geochemical analysis of fluvial sediments on the banks of River Ero using inductively coupled plasma mass spectrometry illustrates their maturity, provenance and tectonic setting. The analysed sediment samples show low SiO2/Al2O3 ratios of 2.92-2.99 (units FL_A, FL_B and FL_E and high SiO2/Al2O3 ratios of 4.064-4.852 (units FL_C, FL_D, FL_F and FL_G. Sediments were geochemically classified as shales (units FL_A, FL_B and FL_E and greywackes (units FL_C, FL_D, FL_F and FL_G. Variability in sediment maturity (FL_F > FL_G >FL_C >FL_D >FL_A > FL_B > FL_E parallels a decreasing order in the ratios of SiO2/Al2O3 and K2O/Al2O3, as well as the proportion of quartz grains and matrix components. Evidence from Al2O3/TiO2, K2O, Rb, La/Co, Th/Co, Cr/ Th, Th/Cr, La/Th-Hf, Th-Hf-Co and rare earth element contents of sediment samples suggest felsic protoliths of upper continental crust in a passive margin tectonic setting. An insignificant contribution of mafic components from the source is, however, inferred based on the Ni and Cr contents of the sediment samples. Combined Eu anomalies <0.85 and (Gd/Ybn ratios <2.0 (1.53- 1.82, average 1.65 suggest post-Archean protoliths.

Distribution, enrichment and sources of thallium in the surface sediments of the southwestern coastal Laizhou Bay, Bohai Sea.

Science.gov (United States)

Zhuang, Wen; Gao, Xuelu

2015-07-15

The concentrations of thallium (Tl) in the surface sediments of the southwestern coastal Laizhou Bay and the rivers it connects were determined. In riverine sediments, the Tl concentrations ranged from 0.34 to 0.76 μg g(-1) in summer; in autumn, the corresponding data were 0.35-1.08 μg g(-1). In marine sediments, the Tl concentrations ranged from 0.36 to 0.58 μg g(-1) in summer; and from 0.30 to 0.56 μg g(-1) in autumn. The grain size, Al and Fe oxides were major factors affecting Tl distribution. Tl in the surface sediments of the studied area was mainly from the natural input with the non-natural input as a subsidiary source. The low concentrations of Tl made it hard to cause potential negative environmental effects in this area. Copyright © 2015 Elsevier Ltd. All rights reserved.

Accumulation and effects of sediment-associated silver nanoparticles to sediment-dwelling invertebrates

DEFF Research Database (Denmark)

Ramskov, Tina; Forbes, Valery E; Gilliland, Douglas

2015-01-01

are in high demand. Here, we examine the effects of exposure to sediment mixed with either aqueous Ag (administered as AgNO3) or Ag NPs (13 nm, citrate-capped) at a nominal exposure concentration of 100 μg Ag/g dry weight sediment on four benthic invertebrates: two clones of the gastropod Potamopyrgus...

Polybrominated diphenyl ethers in fish and sediment from river polluted by electronic waste

Energy Technology Data Exchange (ETDEWEB)

Luo Qian [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong (China); Croucher Institute for Environmental Sciences and Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong (China); Cai Zongwei [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong (China)]. E-mail: zwcai@hkbu.edu.hk; Wong Minghung [Croucher Institute for Environmental Sciences and Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong (China)]. E-mail: mhwong@hkbu.edu.hk

2007-09-20

The present study investigated contamination of polybrominated diphenyl ethers (PBDEs) in sediment and fish samples collected from rivers in Guiyu, China where electronic waste (e-waste) is recycled and disposed. PBDE congeners with mono-to hepta-brominated and deca-brominated substitutions were detected using {sup 13}C{sub 12} isotope dilution GC/MS/MS and GC/MS methods, respectively. The total PBDE concentrations ranged from 4434 to 16088 ng/g (dry weight) in Nanyang River bank sediment, from 55 to 445 ng/g in Nanyang River bottom sediment and 51.3 to 365 ng/g in Lianjiang River bottom sediment in Guiyu compared with those from 16.1 to 21.4 ng/g in wastewater discharged from a vehicle repairing workshop in Lo Uk Tsuen in Hong Kong. No PBDE congeners were detected in bottom sediment and fish from Mai Po Marshes in Hong Kong. The mean concentrations of total PBDEs in mixed muscles of tilapia (Oreochromis spp) from Lianjiang River were 115 ng/g wet weight (ww) and from wastewater in Hong Kong were 4.1 ng/g ww. Highest mean PBDE concentration was obtained in liver (2687 ng/g ww), followed by abdomen muscle (1088 ng/g ww) of bighead carp (Aristichthys nobilis) collected from Nanyang River. A significant correlation of concentration of each PBDE congener between sediment and muscle from Guiyu was observed. The present results of total PBDEs in sediment and fish were 10 and 1000 times higher than other studies. Open burning and dumping of e-waste are the major causes of PBDE contamination.

Application of instrumental neutron activation analysis to assess dietary intake of selenium in Korean adults from meat and eggs

International Nuclear Information System (INIS)

Moon, Jong-Hwa; Kim, Sun-Ha; Chung, Yong-Sam; Lee, Ok-Hee

2013-01-01

Selenium is a key constituent of enzyme in glutathione peroxidase, which is effective in decreasing various types of oxidative stress, Thus, the adequacy of selenium intake is very important in decreasing the risks of various degenerating diseases such as cardiovascular disease, or certain cancers. Lately, the intake of animal foods is increasing among Koreans owing to a dietary transition toward a western style. This study was conducted to measure the selenium content in meat and eggs, and then assessed the selenium intake from these foods. Forty frequently eaten items among meat and eggs were analyzed using an Instrumental Neutron Activation Analysis. The selenium content in 100g of raw meat and eggs ranged from 8.1ug to 50.9ug. In particular, 100g of beef contained 12.4ug to 50.9ug of selenium; pork, 11.2ug to 22.6ug chicken, 10.2ug to 13.7ug and eggs, 28.6ug to 43.0ug. Thus, beef viscera and chicken eggs contain the highest amounts of selenium among these groups. 100g of Pork belly, the most frequently eaten meat type among Koreans, contains 14.6ug of selenium. An evaluation of dietary selenium intake shows that the total selenium supply from meats and eggs was 28.4ug/day and 27.5 ug/day in adult men and women, respectively. These are over one-half of the Korean RNI (Recommended Daily Intake) of 55ug/day. (author)

Effects of sediment-spiked lufenuron on benthic macroinvertebrates in outdoor microcosms and single-species toxicity tests

Energy Technology Data Exchange (ETDEWEB)

Brock, T.C.M., E-mail: theo.brock@wur.nl [Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen (Netherlands); Bas, D.A. [Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam (Netherlands); Belgers, J.D.M. [Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen (Netherlands); Bibbe, L. [Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam (Netherlands); Boerwinkel, M-C.; Crum, S.J.H. [Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen (Netherlands); Diepens, N.J. [Department of Aquatic Ecology and Water Quality Management, Wageningen University, P.O. Box 47, 6700 AA Wageningen (Netherlands); Kraak, M.H.S.; Vonk, J.A. [Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam (Netherlands); Roessink, I. [Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen (Netherlands)

2016-08-15

Highlights: • In outdoor microcosms constructed with lufenuron-spiked sediment we observed that this insecticide persistent in the sediment compartment. • Sediment exposure to lufenuron caused population-level declines (insects and crustaceans) and increases (mainly oligochaete worms) of benthic invertebrates. • The direct and indirect effects observed in the microcosms were supported by results of sediment-spiked single species tests with Chironomus riparius, Hyalella azteca and Lumbriculus variegatus. • The tier-1 effect assessment procedure for sediment organisms recommended by the European Food Safety Authority is protective for the treatment-related responses observed in the microcosm test. - Abstract: Sediment ecotoxicity studies were conducted with lufenuron to (i) complement the results of a water-spiked mesocosm experiment with this lipophilic benzoylurea insecticide, (ii) to explore the predictive value of laboratory single-species tests for population and community-level responses of benthic macroinvertebrates, and (iii) to calibrate the tier-1 effect assessment procedure for sediment organisms. For this purpose the concentration-response relationships for macroinvertebrates between sediment-spiked microcosms and those of 28-d sediment-spiked single-species toxicity tests with Chironomus riparius, Hyalella azteca and Lumbriculus variegatus were compared. Lufenuron persisted in the sediment of the microcosms. On average, 87.7% of the initial lufenuron concentration could still be detected in the sediment after 12 weeks. Overall, benthic insects and crustaceans showed treatment-related declines and oligochaetes treatment-related increases. The lowest population-level NOEC in the microcosms was 0.79 μg lufenuron/g organic carbon in dry sediment (μg a.s./g OC) for Tanytarsini, Chironomini and Dero sp. Multivariate analysis of the responses of benthic macroinvertebrates revealed a community-level NOEC of 0.79 μg a.s./g OC. The treatment

The Effect of Source Suspended Sediment Concentration on the Sediment Dynamics of a Macrotidal Creek and Salt Marsh

Science.gov (United States)

Poirier, E.; van Proosdij, D.; Milligan, T. G.

2017-12-01

Seasonal variability in the sediment dynamics of a Bay of Fundy tidal creek and salt marsh system was analyzed to better understand the ecomorphodynamics of a high suspended sediment concentration intertidal habitat. Data were collected over 62 tides for velocity, suspended sediment concentration, deposition, and grain size at four stations from the creek thalweg to the marsh surface. Five topographic surveys were also conducted throughout the 14-month study. Deposition rates per tide varied spatially from 56.4 g·m-2 at the creek thalweg to 15.3 g·m-2 at the marsh surface. Seasonal variations in deposition in the creek and marsh surface were from 38.0 g·m-2 to 97.7 g·m-2 and from 12.2 g·m-2 to 19.6 g·m-2 respectively. Deposition and erosion were greatest in late fall and winter. This seasonal change, led by higher suspended sediment concentrations, was observed in the creek and at the marsh bank but notably absent from the marsh edge and marsh surface. Sediments were predominantly deposited in floc form (76-83%). Because of high floc content, higher suspended sediment concentrations led to more rapid loss of sediment from suspension. With increasing sediment concentration, deposition increased in the tidal creek and at the marsh bank but not at the marsh edge or marsh surface. This suggests that in highly flocculated environments the water column clears fast enough that very little sediment remains in suspension when the water reaches the marsh and that the sediment concentration during marsh inundation is independent of the initial concentration in the creek.

Identification and validation of single nucleotide polymorphic markers linked to Ug99 stem rust resistance in spring wheat

Science.gov (United States)

Wheat stem rust (Puccinia graminis f. sp. tritici Eriks. and E. Henn.) is one of the most destructive diseases world-wide. Races belonging to Ug99 (or TTKSK) continue to cause crop losses in East Africa and threaten global wheat production. Developing and deploying wheat varieties with multiple race...

Genomic analysis of a novel gene conferring resistance to Ug99 stem rust in Triticum turgidum ssp. dicoccum

Science.gov (United States)

Wheat production is threatened by the disease stem rust, which is caused by the biotrophic fungal pathogen Puccinia graminis Pers.:Pers. f. sp. tritici (Pgt). Among all known Pgt races, TTKSK (Ug99) and TRTTF are significant threats to North American wheat production due to their virulence against f...

Balanced Sediment Fluxes in Southern California's Mediterranean-climate Zone Salt Marshes

Science.gov (United States)

Rosencranz, J. A.; Dickhudt, P.; Ganju, N. K.; Thorne, K.; Takekawa, J.; Ambrose, R. F.; Guntenspergen, G. R.; Brosnahan, S.; MacDonald, G. M.

2015-12-01

Salt marsh elevation and geomorphic stability depends on mineral sedimentation. Many southern California, USA salt marshes import sediment during El Niño storm events, but sediment fluxes and mechanisms during dry weather are also potentially important for marsh stability. We calculated tidal creek sediment fluxes within a sediment starved 1.5 km2 salt marsh (Seal Beach) and a less modified 1 km2 marsh (Mugu) with a watershed sediment supply. We measured salt marsh plain suspended sediment concentration and vertical accretion using single stage samplers and marker horizons. At Seal Beach, a 2014 storm yielded 39 and 28 g/s mean sediment fluxes and imported 12000 and 8800 kg in a western channel. This offset 8700 kg export during two months of dry weather, while landward net fluxes in the eastern channel accounted for 33% of the import. During the storm, suspended sediment concentrations on the marsh plain increased by a factor of four; accretion was 1-2 mm near creek levees. An exceptionally high tide sequence at Mugu yielded 4.4 g/s mean sediment flux, importing 1700 kg, accounting for 20% of dry weather fluxes. Overall, low sediment fluxes were observed, suggesting that these salt marshes are currently geomorphically stable. Our results suggest that storms and exceptionally high lunar tides may play large roles, importing sediment and maintaining dry weather sediment flux balances for southern California salt marshes. However, under future climate change and sea-level rise scenarios, results suggest that balanced sediment fluxes may lead to marsh elevational instability, based on estimated mineral sediment deficits.

Effects of nutrient loading on the carbon balance of coastal wetland sediments

Science.gov (United States)

Morris, J.T.; Bradley, P.M.

1999-01-01

Results of a 12-yr study in an oligotrophic South Carolina salt marsh demonstrate that soil respiration increased by 795 g C m-2 yr-1 and that carbon inventories decreased in sediments fertilized with nitrogen and phosphorus. Fertilized plots became net sources of carbon to the atmosphere, and sediment respiration continues in these plots at an accelerated pace. After 12 yr of treatment, soil macroorganic matter in the top 5 cm of sediment was 475 g C m-2 lower in fertilized plots than in controls, which is equivalent to a constant loss rate of 40 g C m-2 yr-1. It is not known whether soil carbon in fertilized plots has reached a new equilibrium or continues to decline. The increase in soil respiration in the fertilized plots was far greater than the loss of sediment organic matter, which indicates that the increase in soil respiration was largely due to an increase in primary production. Sediment respiration in laboratory incubations also demonstrated positive effects of nutrients. Thus, the results indicate that increased nutrient loading of oligotrophic wetlands can lead to an increased rate of sediment carbon turnover and a net loss of carbon from sediments.

Special Issue ;Sediment cascades in cold climate geosystems;

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Morche, David; Krautblatter, Michael; Beylich, Achim A.

2017-06-01

This Editorial introduces the Special Issue on sediment cascades in cold climate geosystems that evolved from the eighth I.A.G./A.I.G. SEDIBUD (Sediment Budgets in Cold Environments; http://www.geomorph.org/sedibud-working-group/) workshop. The workshop was held from 1st to 4th September 2014 at the Environmental Research Station ;Schneefernerhaus; (http://www.schneefernerhaus.de/en/home.html) located at Mt. Zugspitze, the highest peak of Germany, (2962 m asl). Paper and poster presentations focused on observations, measurements and modeling of geomorphological processes in sediment cascades in cold climate geosystems. This resulting Special Issue brings together ten selected contributions from arctic and alpine environments.

INTERACTIONS AMONG PHOSPHATE AMENDMENTS, MICROBES AND URANIUM MOBILITY IN CONTAMINATED SEDIMENTS

Energy Technology Data Exchange (ETDEWEB)

Knox, A

2007-08-30

The use of sequestering agents for the transformation of radionuclides in low concentrations in contaminated soils/sediments offers considerable potential for long-term environmental cleanup. This study evaluated the influence of four phosphate amendments and two microbial amendments on U availability. The synchrotron X-ray fluorescence mapping of the untreated U-contaminated sediment showed that U was closely associated with Mn. All tested phosphate amendments reduced aqueous U concentration more than 90%, likely due to formation of insoluble phosphate precipitates. The addition of A. piechaudii and P. putida alone were found to reduce U concentrations 63% and 31% respectively. Uranium sorption in phosphate treatments was significantly reduced in the presence of microbes. However, increased microbial activity in the treated sediment led to reduction of phosphate effectiveness. The average U concentration in 1 M MgCl{sub 2} extract from U amended sediment was 437 {micro}g/kg, but in the same sediment without microbes (autoclaved sediment), the extractable U concentration was only 103 {micro}g/kg. When the autoclaved amended sediment was treated with autoclaved biological apatite, U concentration in the 1 M MgCl{sub 2} extract was {approx}0 {micro}g/kg. Together these tests suggest that microbes may enhance U leaching and reduce phosphate amendment remedial effectiveness.

A study of arsenic and chromium contamination in freshwater sediments

International Nuclear Information System (INIS)

Nazaratul Ashifa Abdullah Salim; Abdul Khalik Wood; Alias Mohd Yusof; Mohd Suhaimi Hamzah; Md Suhaimi Elias; Shamsiah Abdul Rahman

2008-08-01

Arsenic (As) is generally known for its toxicity while chromium (Cr) at the appropriate amount is an essential element to man and becomes quite toxic in excessive amount. Anthropogenic activities such as industrialization, agricultural and urbanization have led to the contamination of toxic elements into aquatic that finally end up in the sediment system. Environmental process like diagenetic process causes the toxic metals to migrate from the bedrock materials into the sediment surface and lastly into the water column. This process has been recognized to be the factor of arsenic contamination in well water in several countries such as Bangladesh, Taiwan, USA and Canada. A number of samples of freshwater sediments from identified rivers and lakes at Johor Bharu area had been analyzed to determine the concentration level of As and Cr using neutron activation analysis (NAA) technique. Certified Reference Material (CRM) namely BCSS-1 and IAEA Soil-7 were applied to provide good quality assurance control. The results obtained show that the concentrations of As in the rivers and lakes are 10-33 mg/g and 18-62 mg/g, respectively. The concentrations of Cr in the rivers range between 25 mg/g to125 mg/g, while in the lake sediments the concentrations range between 173 mg/g to 301 mg/g. The lakes sediments have higher As and Cr contents than the river sediment. The results of the As and Cr concentrations were then compared to the background value proposed by National Oceanic and Atmospheric Administration (NOAA), USA and interim freshwater sediment quality guidelines value established by Canadian Sediment Quality Guidelines for The Protection of Aquatic Life. (Author)

Butiltins Compound in Seawater and Sediment of Banten Bay

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Hamidah Razak

2004-08-01

Full Text Available bservation on butiltin (BTs compound content in seawater and sediments from Banten Bay were conducted in August 2003 and October 2003. Butiltin content including TBT, DBT and MBT on August 2003 respectively range between <2ng Sn/l, <2 to 9 ng Sn/l and < 5 to 17 ng Sn/l and on October 2003 was found respectively nd to <2 ng Sn/l, <0.5 to 12 ng Sn/g, 0.5 to 2.7 ng Sn/g and <0.5 to 2.2 ng Sn/g, and on October 2003 was found varied from <0.5 to 4.2ng Sn/g, <0.5 to 1.1ng Sn/g and <0.5 to 1 ng Sn/g. Content of TBT was found on August 2003 higher than October 03 and also the content of TBT compound in sediments was high compared to waters. It indicated that there was accumulation of TBT in sediment. The minimal risk of TBT in seaport and for marine life according to Minister of environment in Keputusan Menteri Negara Kependudukan dan Lingkungan Hidup No.51 tahun 2004 is 10 ng/l. The results showed that Banten Bay is still appropiate for seaport and marine life.

Effects of composition of labile organic matter on biogenic production of methane in the coastal sediments of the Arabian Sea.

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Gonsalves, Maria-Judith; Fernandes, Christabelle E G; Fernandes, Sheryl Oliveira; Kirchman, David L; Bharathi, P A Loka

2011-11-01

Coastal regions are potential zones for production of methane which could be governed by ecological/environmental differences or even sediment properties of a niche. In order to test the hypothesis that methanogenesis in most marine sediments could be driven more by proteins than by carbohydrates and lipid content of labile organic matter (LOM), incubation experiments were carried out with sediments from different environmental niches to measure methane production. The methane production rates were examined in relationship to the sediment biochemistry, i.e., carbohydrates, proteins, and lipids. The gas production measured by head space method ranged from 216 ng g( -1) day( -1) in the mangrove sediments to 3.1 μg g( -1) day( -1) in the shallow Arabian Sea. LOM ranged from 1.56 to 2.85 mg g( -1) in the shallow Arabian Sea, from 3.35 to 5.43 mg g( -1) in the mangrove estuary, and from 0.66 to 0.70 mg g( -1) in the sandy sediments with proteins contributing maximum to the LOM pool. Proteins influenced methane production in the clayey sediments of shallow depths of the Arabian Sea (r = 0.933, p methane production. The gas production was more pronounced in shallow and surface sediments and it decreased with depth apparently governed by the decrease in lability index. Thus, the lability index and protein content are important factors that determine methane production rates in these coastal ecosystems.

Microplastic particles in sediments from Danish waters

DEFF Research Database (Denmark)

Strand, Jakob; Lassen, Pia; Shashoua, Yvonne

. In some samples, several hundred particles consisting of fibres, flakes, spherules, and/or granules were identified per 100 g sediment, and also in sediments from open waters. Relationships to sediment characteristics (e.g. dry weight, TOC, grain size) and inorganic and organic contaminants including...

Aliphatic hydrocarbons in surface sediments from South China Sea off Kuching Division, Sarawak

International Nuclear Information System (INIS)

Hafidz Yusoff; Zaini Assim; Samsur Mohamad

2012-01-01

Eighteen surface sediment samples collected from South China Sea off Kuching Division, Sarawak were analyzed for aliphatic hydrocarbons. These hydrocarbons were recovered from sediment by Soxhlet extraction method and then analyzed using gas chromatography equipped with mass spectrometer (GC/ MS). Total concentrations of aliphatic hydrocarbons in surface sediments from South China Sea off Kuching division are ranged from 35.6 μg/ g to 1466.1 μg/ g dry weights. The sediments collected from Bako Bay, Kuching showed high concentrations of total aliphatic hydrocarbons. Several molecular indices were used to predict the predominant sources of hydrocarbons. Carbon preference index (CPI) value revealed widespread anthropogenic input in this study area (CPI= 0 to 4.1). The ratio of C 31 / C 19 and C 29 / C 31 indicated that major input of aliphatic hydrocarbon mostly transfer by lateral input to the marine environment than atmospheric movements. Generally, the concentrations of aliphatic hydrocarbons in sediment from South China Sea off Kuching division are generally higher compare to other area in the world. (author)

Use of a simplified spectrophotometric method for quantitative determination of glucose-6-phosphate dehydrogenase activity in normal children from two day-care centers of the city of São Paulo

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Roberto Muller

2003-06-01

Full Text Available Objective: To evaluate the applicability of a simplified method forquantitative determination of glucose-6-phosphate dehydrogenaseactivity in normal children; to determine the mean, standarddeviation and threshold value under which the enzyme activity isconsidered deficient. Methods: Blood samples were collected from201 children from two day-care centers in the city of São Paulo.The subjects were considered normal based on physicalexamination and laboratory tests. The enzyme activity wasdetermined in red blood cells of normal children using the “TestCombination G-6-PDH®” kit. The following statistical analyses werecarried out: the results were submitted to Student’s t test,Kolmogorov-Smirnov test, lower confidence interval (one-tailedtest and Spearman’s correlation coefficient. Results: The meanhemoglobin value for girls was slightly higher than the mean valuefor boys, but this difference was not statistically significant. Therewas no statistical difference in mean enzyme activities for Caucasianand non-Caucasian children. There was no significant correlation amongenzyme activity levels, red blood cells, hemoglobin levels,hematocrit, reticulocytes, white blood cells and age of patients.The mean enzyme activity for boys was 4.448 U/g Hb, standarddeviation = 1.380 U/g Hb. For girls, the mean enzyme activity was4.531 U/g Hb, standard deviation = 1.386 U/g Hb, and the differencewas not statistically significant. Therefore, the two populationgroups were considered as one single population, presenting amean enzyme activity of 4.490 U/g Hb, standard deviation = 1.380 U/g Hb.Since the distribution curve of enzyme activity values was normal,a lower confidence interval was determined (one-tailed test, witha cutoff point of 2.227 U/g Hb. Conclusion: The method used bySolem proved to be simple, fast, very accurate and useful to detectglucose-6-phosphate dehydrogenase activity and to identifychildren with enzyme deficiency.

Runoff and sediment transport in a degraded area

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Edivaldo Lopes Thomaz

2012-02-01

Full Text Available Gully erosion occurs by the combined action of splash, sheetwash and rill-wash (interrill and rill erosion. These erosion processes have a great capacity for both sediment production and sediment transport. The objectives of this experiment were to evaluate hydrological and sediment transport in a degraded area, severely dissected by gullies; to assess the hydraulic flow characteristics and their aggregate transport capacity; and to measure the initial splash erosion rate. In the study area in Guarapuava, State of Paraná, Brazil (lat 25º 24' S; long 51º24' W; 1034 m asl, the soil was classified as Cambissolo Húmico alumínico, with the following particle-size composition: sand 0.116 kg kg-1; silt 0.180 kg kg-1; and clay 0.704 kg kg-1. The approach of this research was based on microcatchments formed in the ground, to study the hydrological response and sediment transport. A total of eight rill systems were simulated with dry and wet soil. An average rainfall of 33.7 ± 4.0 mm was produced for 35 to 54 min by a rainfall simulator. The equipment was installed, and a trough was placed at the end of the rill to collect sediments and water. During the simulation, the following variables were measured: time to runoff, time to ponding, time of recession, flow velocity, depth, ratio of the initial splash and grain size. The rainsplash of dry topsoil was more than twice as high as under moist conditions (5 g m-2 min-1 and 2 g m-2 min-1, respectively. The characteristics of the flow hydraulics indicate transition from laminar to turbulent flow [Re (Reynolds number 1000-2000]. In addition, it was observed that a flow velocity of 0.12 m s-1 was the threshold for turbulent flow (Re > 2000, especially at the end of the rainfall simulation. The rill flow tended to be subcritical [Fr (Froude Number < 1.0]. The variation in hydrological attributes (infiltration and runoff was lower, while the sediment yield was variable. The erosion in the rill systems was

Benzene and MTBE Sorption in Fine Grain Sediments

Science.gov (United States)

Leal-Bautista, R. M.; Lenczewski, M. E.

2003-12-01

The practice of adding methyl tert-butyl ether (MTBE) to gasoline started in the late 1970s and increased dramatically in the 1990s. MTBE first was added as a substitute for tetra-ethyl lead then later as a fuel oxygenate. Although the use of MTBE has resulted in significant reduction in air pollution, it has become a significant groundwater contaminant due to its high solubility in water, high environmental mobility, and low potential for biodegradation. A recent report (1999-2001) by the Metropolitan Water District of Southern California in collaboration with United State Geological Survey and the Oregon Health and Science University found that MTBE was the second most frequent detected volatile organic compound in groundwater. In Illinois, MTBE has been found in 26 of the 1,800 public water supplies. MTBE has also been blended in Mexico into two types of gasoline sold in the country by the state oil company (PEMEX) but is not monitored in groundwater at this time. Early research on MTBE considered it unable to adsorb to soils and sediments, however, by increasing the organic matter and decreasing the size of the grains (silts or clays) this may increase sorption. The objective of this study is to determine if fine grained materials have the potential for sorption of MTBE due to its high specific surface area (10-700 m 2/g) and potentially high organic matter (0.5-3.8%). The experiment consisted of sorption isotherms to glacial tills from DeKalb, Illinois and lacustrine clays from Chalco, Mexico. Experiments were performed with various concentrations of MTBE and benzene (10, 50, 100, 500 and 1000 ug/L) at 10° C and 25° C. Results showed a range of values for the distribution coefficient (Kd, linear model). At 10° C the Kd value for MTBE was 0.187 mL/g for lacustrine clay while the glacial loess had a value of 0.009 mL/g. The highest Kd values with MTBE were 0.2859 mL/g for organic rich lacustrine clays and 0.014 mL/g for glacial loess at 25° C. The highest

Biochemical Effects of six Ti02 and four Ce02 Nanomaterials in HepG2 cells

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Abstract The potential mammalian hepatotoxicity of nanomaterials were explored in dose-response and structure-activity studies with human hepatic HepG2 cells exposed to between 10 and 1000 ug/ml of six different TiO2 and four CeO2 nanomaterials for 3 days. Var...

Carbon Tetrachloride Partition Coefficients Measured by Aqueous Sorption to Hanford Sediments from Operable Units 200-UP-1 and 200-ZP-1

International Nuclear Information System (INIS)

Wellman, Dawn M.; Riley, Robert G.; Cordova, Elsa A.; Parker, Kent E.; Mitroshkov, Alexandre V.

2007-01-01

Kd values obtained on sediment samples from 200-UP-1 and 10-ZP-1 contribute to a larger Kd database that exists for other Hanford sediments, and contains significant desorption data for CCl4. Adsorption results presented here validate the use of a linear adsorption isotherm (Kd) to predict short contact time CCl4 adsorption to sediments in 200-UP-1 groundwater plume for a distinct ranges in CCl4 concentration. However, this does not imply that values of Kd will be constant if the groundwater chemical composition at 200-UP-1 changes with space or time. Additionally, results presented here suggest the potential significance of slower intraparticle diffusion on the long-term fate of CCl4 within the subsurface Hanford environment. Such behavior could afford prolonged desorption of CCl4 and serve as a long-term source of contaminant CCl4 to the aquifer. Further evaluation of possible bimodal sorption behavior for CCl4 and the mechanism of CCl4 sequestration should be the subject of future investigations to provide a thorough, mechanistic understanding of the retention and long-term fate of CCl4. Comparison of previous data with new results (e.g., from this study) will allow inferences to be made on how the 200-UP-1 Kd values for CCl4 may compare with sediments from other Hanford locations. This site-specific sorption data, when complemented by the chemical, geologic, mineralogic, hydrologic, and physical characterization data that are also being collected (see Sampling and Analysis Plan for the 200-UP-1 Groundwater Monitoring Well Network, DOE 2002) can be used to develop a robust, scientifically defensible data base to allow risk predictions to be generated and to aid in future remediation decisions for the 200-UP-1 and 200-ZP-1 operable units

Source characterization using compound composition and stable carbon isotope ratio of PAHs in sediments from lakes, harbor, and shipping waterway

International Nuclear Information System (INIS)

Kim, Moonkoo; Kennicutt, Mahlon C.; Qian, Yaorong

2008-01-01

Molecular compositions and compound specific stable carbon isotope ratios of polycyclic aromatic hydrocarbons (PAH) isolated from sediments were used to characterize possible sources of contamination at an urban lake, a harbor, a shipping waterway, and a relatively undisturbed remote lake in the northwest United States. Total PAH concentrations in urban lake sediments ranged from 66.0 to 16,500 μg g -1 dry wt. with an average of 2600 μg g -1 , which is ∼ 50, 100, and 400 times higher on average than PAH in harbor (48 μg g -1 on average), shipping waterway (26 μg g -1 ), and remote lake (7 μg g -1 ) sediments, respectively. The PAH distribution patterns, methyl phenanthrene/phenanthrene ratios, and a pyrogenic index at the sites suggest a pyrogenic origin for PAHs. Source characterization using principal component analysis and various molecular indices including C2-dibenzothiophenes/C2-phenanthrenes, C3-dibenzothiophenes/C3-phenanthrenes, and C2-chrysenes/C2-phenanthrenes ratios, was able to differentiate PAH deposited in sediments from the four sites. The uniqueness of the source of the sediment PAHs from urban lake was also illustrated by compound specific stable carbon isotope analysis. It was concluded that urban lake sediments are accumulating PAH from sources that are unique from contamination detected at nearby sites in the same watershed

Evaluation of the sedimentation rate in a sediment profile of Bortolan Dam, MG, Brazil

International Nuclear Information System (INIS)

Almeida, Heleine C. de; Soares, Flávio V.T.S.; Taddei, Maria Helena T.; Mazzilli, Barbara P.

2017-01-01

Volcanic extrusion is one of the main causes for the high levels of environmental radioactivity in the region of Poços de Caldas (MG, Brazil). Uranium mining during the 80's further increased the background radiation in the region, especially in the Ribeirao das Antas watershed, where Bortolan Dam is located. Besides the uranium mining facility operating in the region, other activities, such as agriculture, were also responsible for the enhancement of the levels of radioactivity. The dam sediment profile provides an appropriate compartment for the study of the temporal variation of these radionuclides and for the evaluation of anthropogenic contamination. The main aim of this study is to evaluate the sedimentation rate and the dating of a profile collected in Bortolan Dam, by using the geochronology method. The activity concentration of "2"2"6Ra and "2"1"0Pb were measured in the sediment profile by gamma spectrometry. The concentration of "2"2"6Ra and "2"1"0Pb varied from (217 ± 9) Bq kg"-"1 to (286 ± 12) Bq kg"-"1 and from (262 ± 11) Bq kg"-"1 to (322 ± 34) Bq·kg"-"1 respectively; and the sedimentation rates varied from 0.021 to 0.144 g cm"-"2y"-"1. (author)

Hydrocarbon pollution in the sediment from the Jarzouna-Bizerte coastal area of Tunisia (Mediterranean Sea).

Science.gov (United States)

Zrafi-Nouira, I; Khedir-Ghenim, Z; Zrafi, F; Bahri, R; Cheraeif, I; Rouabhia, M; Saidane-Mosbahi, D

2008-06-01

This study investigated the presence and origin of hydrocarbon pollution in industrial waste water sediments found near the Jarzouna (Bizerte, Tunisia) oil refinery. Analyses of surface sediments (layer 1) and deep sediments (layer 2) showed that Total Hydrocarbon (TH) concentrations ranged from 602 +/- 7.638 microg/g in layer-1 to 1270 +/- 2.176 microg/g in layer-2. The results suggest that the deeper the sediment, the higher the level of total hydrocarbon found. The sedimentary Non Aromatic Hydrocarbon (NAH) and Aromatic Hydrocarbon (AH) concentrations ranged from 66.22 +/- 1.516 to 211.82 +/- 10.670 microg/g for NAH, and from 13.84 +/- 0.180 to 115.60 +/- 2.479 microg/g for AH. The high variability of these concentrations was associated with the location of the sediment collection sites. Aliphatic biomarker analysis revealed petroleum contamination close to the refinery rejection site, and biogenic sources further away. Petroleum contamination may be associated with increased industrial activity in the area of Jarzouna-Bizerte in the Mediterranean Sea.

Spatial distribution of heavy metals in sediments from the Gulf of Paria, Trinidad

International Nuclear Information System (INIS)

Norville, W.

2005-01-01

The Gulf of Paria receives heavy metal input from urban runoff, industrial and agricultural activity, sewage and domestic wastes: both from the west coast and from inland areas of Trinidad. Non-residual concentrations of nine metals, as well as total mercury concentrations, were used to determine spatial distributions of heavy metals in sediments in the Gulf of Paria. Surficial sediment samples were collected at 37 stations, which included the mouths of 11 major rivers that flow into the Gulf of Paria. Stations were sampled twice during the wet season (July 1998 and November/ December 1998) and twice during the dry season (March 1999 and April 1999). Sediments were analyzed for aluminium (Al), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), nickel (Ni), zinc (Zn) and mercury (Hg). Total Organic Carbon (TOC) and grain size analyses were also performed on the sediments. Principal component analysis showed that sediments from river mouths subject to greatest land use and anthropogenic input, were distinct from other sediments in the Gulf of Paria. This was due to higher Pb, Zn, Cu and Hg concentrations (3.53-73.30 μ g-', 45.8-313.9 μg g-', 8.43-39.71 μg g' and 0.03-0.10 μg g-', respectively). Sediments further from the coast were also distinct due to their higher Al, Fe, Cr and Mn concentrations (1.37-3.16 mg g-', 9.51-18.91 mg g-',17.22-28.41 μg g-' and 323.6--1,564.2 pg g-', respectively). Cd and Pb were higher in the wet season while Ni was higher in the dry season. Pb, Zn, Cu and Hg were correlated with each other and with TOC. Correlation was also observed between Al, Fe, Cr, Mn and Ni. Al, Fe, Cr and Mn were correlated with percentage clay in sediments. The results suggest that Pb, Zn, Cu and Hg are preferentially removed by organic matter, which settles at the river-mouths, while Al, Fe, Cr, Mn, and Ni become associated with clay minerals and are transported away from the coast.(From the author) [es

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in sediments from the Gulf of Batabanó, Cuba.

Science.gov (United States)

Alonso-Hernandez, C M; Mesa-Albernas, M; Tolosa, I

2014-01-01

The spatial distribution of various organochlorinated compounds, e.g. PCBs, DDTs, HCB and HCHs, were investigated in sediments of the Gulf of Batabanó, Cuba. Among the target organochlorine compounds measured, ΣDDT isomers were the predominant contaminant with concentrations ranging from 0.019 to 1.27 ng g(-1)dry wt. Lindane was present at very low concentrations in the range n.d. to 0.05 ng g(-1), while PCBs and other organochlorine pesticide residues, such as HCB, Heptaclor, Aldrin and Mirex were lower than detection limits (∼0.010 ng g(-1)). According to established sediment quality guidelines, the OCPs concentrations encountered in the surface sediments are probably not having an adverse effect on sediment dwelling organisms. Compared to concentrations reported in coastal environments from other parts of the world, PCBs and OCs concentrations in surface sediments of Batabanó Gulf were low and similar to the reported for remote and pristine environments. These results contribute to the sparse regional database for organochlorinated compounds in the Caribbean marine environment. Copyright © 2013. Published by Elsevier Ltd.

Modeling Aeolian Transport of Contaminated Sediments at Los Alamos National Laboratory, Technical Area 54, Area G: Sensitivities to Succession, Disturbance, and Future Climate

Energy Technology Data Exchange (ETDEWEB)

Whicker, Jeffrey J. [Los Alamos National Laboratory; Kirchner, Thomas B. [New Mexico State University; Breshears, David D. [University of Arizona; Field, Jason P. [University of Arizona

2012-03-27

The Technical Area 54 (TA-54) Area G disposal facility is used for the disposal of radioactive waste at Los Alamos National Laboratory (LANL). U.S. Department of Energy (DOE) Order 435.1 (DOE, 2001) requires that radioactive waste be managed in a manner that protects public health and safety and the environment. In compliance with that requirement, DOE field sites must prepare and maintain site-specific radiological performance assessments for facilities that receive waste after September 26, 1988. Sites are also required to conduct composite analyses for facilities that receive waste after this date; these analyses account for the cumulative impacts of all waste that has been (and will be) disposed of at the facilities and other sources of radioactive material that may interact with these facilities. LANL issued Revision 4 of the Area G performance assessment and composite analysis in 2008. In support of those analyses, vertical and horizontal sediment flux data were collected at two analog sites, each with different dominant vegetation characteristics, and used to estimate rates of vertical resuspension and wind erosion for Area G. The results of that investigation indicated that there was no net loss of soil at the disposal site due to wind erosion, and suggested minimal impacts of wind on the long-term performance of the facility. However, that study did not evaluate the potential for contaminant transport caused by the horizontal movement of soil particles over long time frames. Since that time, additional field data have been collected to estimate wind threshold velocities for initiating sediment transport due to saltation and rates of sediment transport once those thresholds are reached. Data such as these have been used in the development of the Vegetation Modified Transport (VMTran) model. This model is designed to estimate patterns and long-term rates of contaminant redistribution caused by winds at the site, taking into account the impacts of plant

Modeling Aeolian Transport of Contaminated Sediments at Los Alamos National Laboratory, Technical Area 54, Area G: Sensitivities to Succession, Disturbance, and Future Climate

International Nuclear Information System (INIS)

Whicker, Jeffrey J.; Kirchner, Thomas B.; Breshears, David D.; Field, Jason P.

2012-01-01

The Technical Area 54 (TA-54) Area G disposal facility is used for the disposal of radioactive waste at Los Alamos National Laboratory (LANL). U.S. Department of Energy (DOE) Order 435.1 (DOE, 2001) requires that radioactive waste be managed in a manner that protects public health and safety and the environment. In compliance with that requirement, DOE field sites must prepare and maintain site-specific radiological performance assessments for facilities that receive waste after September 26, 1988. Sites are also required to conduct composite analyses for facilities that receive waste after this date; these analyses account for the cumulative impacts of all waste that has been (and will be) disposed of at the facilities and other sources of radioactive material that may interact with these facilities. LANL issued Revision 4 of the Area G performance assessment and composite analysis in 2008. In support of those analyses, vertical and horizontal sediment flux data were collected at two analog sites, each with different dominant vegetation characteristics, and used to estimate rates of vertical resuspension and wind erosion for Area G. The results of that investigation indicated that there was no net loss of soil at the disposal site due to wind erosion, and suggested minimal impacts of wind on the long-term performance of the facility. However, that study did not evaluate the potential for contaminant transport caused by the horizontal movement of soil particles over long time frames. Since that time, additional field data have been collected to estimate wind threshold velocities for initiating sediment transport due to saltation and rates of sediment transport once those thresholds are reached. Data such as these have been used in the development of the Vegetation Modified Transport (VMTran) model. This model is designed to estimate patterns and long-term rates of contaminant redistribution caused by winds at the site, taking into account the impacts of plant

Underground gas storage Uelsen: Findings from planning, building and commissioning the surface buildings and structures; Untertagegasspeicher (UGS) Uelsen: Erkenntnisse aus Planung, Bau und Inbetriebnahme der obertaegigen Anlagen

Energy Technology Data Exchange (ETDEWEB)

Focke, H.; Brueggmann, R.; Mende, F.; Steinkraus, D.; Wauer, R. [BEB Erdgas und Erdoel GmbH, Hannover (Germany)

1998-12-31

The article describes the concepts of the plants and equipment and the specific features of the underground storage at Uelsen. The underground storage will be purpose-built as an H-gas storage in a nearly depleted sandstone deposit. At a nominal deliverability of 250.000 cubic m/h (Vn) the storage at Uelsen has more potential for expansion. This potential was taken into account by designing appropriate pressure stages, capacities, performance characteristics and space. (orig.). [Deutsch] Die nachfolgende Veroeffentlichung stellt das anlagentechnische Grundkonzept und die spezifischen Besonderheiten des UGS Uelsen dar. Der im suedwestlichen Niedersachsen als H-Gasspeicher in einer nahezu ausgefoerderten Buntsandsteinlagerstaette eingerichtete UGS Uelsen wird in mehreren Ausbaustufen bedarfsgerecht fertiggestellt. Bei einer Nennentnahmekapazitaet von 450.000 m{sup 3}/h (Vn) und einer Nenninjektionsleistung von 250.000 m{sup 3}/h (Vn) weist der UGS Uelsen noch weiteres Potential fuer Erweiterungen auf. Dieses Ausbaupotential wurde bei der Planung und dem Bau der bestehenden Anlagen durch Festlegung entsprechender Druckstufen, Kapazitaeten, Leistungsgroessen und Platzanordnungen beruecksichtigt. (orig.)

The Effects of Zebra Mussels on Nitrogen Cycling and Sediment Physiochemical Characteristics: A Laboratory Experiment.

Science.gov (United States)

Bruesewitz, D. A.; Tank, J. L.; Bernot, M. J.

2005-05-01

Many ecosystems experiencing anthropogenic nitrogen loading have also been invaded by zebra mussels (ZM), therefore it is important to understand how these human-induced changes interact. In particular, ZM may impact biogeochemical transformations. We hypothesized that high NH4+ waste from ZM will increase sediment nitrification rates, and increase NO3--N available for denitrification. To test this prediction, aquaria were stocked with either no ZM or 10,000 individuals m-2. Sediment nitrification (via nitrapyrin-inhibition technique), denitrification (via chloramphenicol-amended acetylene block technique), and sediment O2 profiles (using microelectrodes) were measured weekly for 1 month. The presence of ZM increased nitrification and denitrification rates over initial conditions throughout all weeks (RM ANOVA, p<0.05). Sediment nitrification in the ZM aquaria increased to 47 ± 2.1 μ g NH4+ -NgAFDM-1h-1 by the 3rd week in comparison to 24 ± 4.4 μ g NH4+ -NgAFDM-1h-1 in control aquaria. Sediment denitrification peaked at week 2 in the ZM aquaria at 330 ± 24 μ g N2O gAFDM-1h-1 but remained low in control aquaria throughout. There was a stronger correlation between nitrification and denitrification rates in the presence of ZM (R=0.32, 0.12 respectively). These results, in addition to more frequent hypoxia in sediment oxygen profiles, suggest closer coupling between nitrification and denitrification when ZM are present.

Alkane and polycyclic aromatic hydrocarbons in sediments and benthic invertebrates of the northern Chukchi Sea

Science.gov (United States)

Harvey, H. Rodger; Taylor, Karen A.

2017-10-01

The Hanna Shoal region represents an important northern gateway for transport and deposition in the Chukchi Sea. This study determined the concentration and distribution of organic contaminants (aliphatic hydrocarbon and polycyclic aromatic hydrocarbons, PAHs) in surface sediments from 34 sites across Hanna Shoal. Up to 31 total PAHs, including parent and alkyl homologues were detected with total concentrations ranging from a low of 168 ng g-1 the western flank of Hanna Shoal (station H34) to 1147 ng g-1 at station in Barrow Canyon (station BarC5). Alkyl PAHs were more abundant than parent structures and accounted for 53-64% of the summed concentrations suggesting overall at background levels (< 1600 ng g-1) in sediments. Alkane (C15-C33) hydrocarbons ranged from 4.3 μg g-1 on the southern flank of Hanna shoal to 31 μg g-1 at a northern station. Sediments were often dominated by short chain (C15-C22) alkanes with overall terrestrial aquatic ratios (TAR) for the region averaging 0.20. Based on the ratio of Fl/(Fl+ Py) and BaF/(Baf+BeP) verses (BA/BA+Ch) in sediments, PAHs are largely derived from petrogenic sources with minor amounts of mixed combustion sources. A diversity of PAHs were detected in the northern whelk Neptunea heros foot muscle with total concentrations ranging from 0.14 to 1.5 μg g-1 dry tissue wt. Larger (and presumably older) animals showed higher levels of PAH per unit muscle tissue, suggesting that animals may bioaccumulate PAHs over time, with low but increasing concentrations also present in internal and external eggs. Alkane hydrocarbons were also higher in whelks with distributions similar to that seen in sediments. The mussel Muscularus discors collected in Barrow Canyon showed constrained distributions and substantially lower concentrations of both PAHs and alkanes than the surrounding surface sediments.

Thallium in fractions of sediments formed during the 2004 tsunami in Thailand.

Science.gov (United States)

Lukaszewski, Zenon; Karbowska, Bozena; Zembrzuski, Wlodzimierz; Siepak, Marcin

2012-06-01

Thallium is a highly toxic element. Its concentration in sediment fractions from the 2004 tsunami in Thailand was investigated. A modified BCR procedure was used for sequential extraction. Tl was determined by flow injection differential pulse anodic stripping voltammetry. It was found that the majority of thallium in the investigated tsunami sediments (86-97 percent) is entrapped in the alumosilicate parent matter i.e. it is entirely immovable. Only the total destruction of this residual fraction with hydrofluoric acid made this thallium available. The conclusion strongly supports the hypothesis that thallium is mainly entrapped in alumosilicate parent matter. Total thallium concentration in the investigated tsunami sediments was divergent in various samples from 0.37 to 1.13 μg g(-1) and significantly different from the reference area (0.05 μg g(-1)). Tsunami sediment fractions from different sampling points are divergent in terms of total thallium concentration and concentration of mobile thallium. Generally, mobile thallium concentration was growing in sequence: water soluble fractionthallium concentration in the reducible fraction was higher than in the oxidizable fraction. Copyright © 2012 Elsevier Inc. All rights reserved.

Creation of a magnetic barrier at a noble q close to physical midpoint between two resonant surfaces in the ASDEX UG tokamak

Science.gov (United States)

Vazquez, Justin; Ali, Halima; Punjabi, Alkesh

2009-11-01

Ciraolo, Vittot and Chandre method of building invariant manifolds inside chaos in Hamiltonian systems [Ali H. and Punjabi A, Plasma Phys. Control. Fusion, 49, 1565--1582 (2007)] is used in the ASDEX UG tokamak. In this method, a second order perturbation is added to the perturbed Hamiltonian [op cit]. It creates an invariant torus inside the chaos, and reduces the plasma transport. The perturbation that is added to the equilibrium Hamiltonian is at least an order of magnitude smaller than the perturbation that causes chaos. This additional term has a finite, limited number of Fourier modes. Resonant magnetic perturbations (m,n) = (3,2)+(4,3) are added to the field line Hamiltonian for the ASDEX UG. An area-preserving map for the field line trajectories in the ASDEX UG is used. The common amplitude δ of these modes that gives complete chaos between the resonant surfaces ψ43 and ψ32 is determined. A magnetic barrier is built at a surface with noble q that is very nearly equals to the q at the physical midpoint between the two resonant surfaces. The maximum amplitude of magnetic perturbation for which this barrier can be sustained is determined. This work is supported by US Department of Energy grants DE-FG02-07ER54937, DE-FG02-01ER54624 and DE-FG02-04ER54793.

Tracking paraglacial sediment with cosmogenic 10Be using an example from the northwest Scottish Highlands

Science.gov (United States)

Fame, Michelle L.; Owen, Lewis A.; Spotila, James A.; Dortch, Jason M.; Caffee, Marc W.

2018-02-01

Beryllium-10 concentrations in samples of sediment and bedrock from five study sites across the Scottish Highlands trace paraglacial sediment sources and define the nature of glacial erosion for the late Quaternary. Exposure ages derived from 10Be concentrations in ridge and lower elevation bedrock range from 10 to 33 ka, which suggest that polythermal ice and warm based ice were primarily responsible for producing glacial sediment. Comparisons of 10Be concentrations between catchment-wide sediment (2.06 ± 0.34 × 104 to 11.24 ± 1.54 × 104 atoms g-1 SiO2; n = 33), near surface deposits (2.71 ± 0.33 × 104 to 3.48 ± 0.49 × 104 atoms g-1 SiO2; n = 6), 4-m-thick deep till (0.68 × 10410Be atoms g-1 SiO2; n = 1), ridge bedrock (8.93 ± 0.47 × 104 to 34.05 ± 1.66 × 104 atoms g-1 SiO2; n = 20), and lower elevation polished bedrock (6.74 ± 0.67 × 104 to 12.65 ± 0.7 × 104 atoms g-1 SiO2, n = 5) indicate that most sand fluxing through catchments in the Scottish Highlands is sourced from the remobilization and vertical mixing of near surface deposits. These findings indicate that glaciogenic material continues to dominate paraglacial sediment budgets more than 11 ka after deglaciation.

Evaluation of the sedimentation rate in a sediment profile of Bortolan Dam, MG, Brazil

Energy Technology Data Exchange (ETDEWEB)

Almeida, Heleine C. de; Soares, Flávio V.T.S.; Taddei, Maria Helena T.; Mazzilli, Barbara P., E-mail: heleine.almeida@ipen.br, E-mail: mhtaddei@cnen.gov.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Laboratório de Poços de Caldas (LAPOC/CNEN-MG), Pocos de Caldas, MG (Brazil)

2017-11-01

Volcanic extrusion is one of the main causes for the high levels of environmental radioactivity in the region of Poços de Caldas (MG, Brazil). Uranium mining during the 80's further increased the background radiation in the region, especially in the Ribeirao das Antas watershed, where Bortolan Dam is located. Besides the uranium mining facility operating in the region, other activities, such as agriculture, were also responsible for the enhancement of the levels of radioactivity. The dam sediment profile provides an appropriate compartment for the study of the temporal variation of these radionuclides and for the evaluation of anthropogenic contamination. The main aim of this study is to evaluate the sedimentation rate and the dating of a profile collected in Bortolan Dam, by using the geochronology method. The activity concentration of {sup 226}Ra and {sup 210}Pb were measured in the sediment profile by gamma spectrometry. The concentration of {sup 226}Ra and {sup 210}Pb varied from (217 ± 9) Bq kg{sup -1} to (286 ± 12) Bq kg{sup -1} and from (262 ± 11) Bq kg{sup -1} to (322 ± 34) Bq·kg{sup -1} respectively; and the sedimentation rates varied from 0.021 to 0.144 g cm{sup -2}y{sup -1}. (author)

Root cause analysis of the fatigue failures of the pulsation dampers of a large underground gas storage (UGS) system

NARCIS (Netherlands)

Eijk, A.; Lange, D. de; Maljaars, J.; Tenbrock-Ingenhorst, A.; Gottmer, A.

2014-01-01

Two large identical 6-cylinder Ariel JGB/6 reciprocating compressors each of 7.5 MW, are used for an underground gas storage system (UGS) plant of RWE Gasspeicher GmbH located in Epe, Germany. The system is in operation since 2005. In 2011 several internals parts (baffle plates and baffle choke

Marine sediments as a sink, and contaminated sediments as a diffuse source of radionuclides

International Nuclear Information System (INIS)

Salbu, B.; Borretzen, P.

1997-01-01

Full text: Marine sediments may act as a sink for radionuclides originating from atmospheric fallout (e.g. Chernobyl accident), for radionuclides in discharges from nuclear installations (e.g. Sellafield, UK) for river transported radionuclides, and radionuclides released from nuclear waste dumped at sea (e.g. fjords at Novaya Zemlya). In order to assess short and long term consequences of radionuclides entering the marine ecosystem, the role of sediments as a relatively permanent sink and the potential for contaminated sediments to act as a diffuse source should be focused. The retention of radionuclides in sediments will depend on the source term, i.e. the physico-chemical forms of radionuclides entering the system and on interactions with various sediment components. Radionuclides associated with particles or aggregating polymers are removed from the water phase by sedimentation, while sorption to surface sediment layers is of relevance for ionic radionuclide species including negatively charged colloids. With time, transformation processes will influence the mobility of radionuclides in sediments. The diffusion into mineral lattices will increase fixation, while the influence of for instance red/ox conditions and bio-erosion may mobilize radionuclides originally fixed in radioactive particles. Thus, information of radionuclides species, surface interactions, transformation processes and kinetics is essential for reducing the uncertainties in marine transfer models. Dynamic model experiments where chemically well defined tracers are added to a sea water-marine sediment system are useful for providing information on time dependent interactions and distribution coefficients. When combined with sequential extraction techniques, information on mobility and rate of fixation is subsequently attained. In the present work experimental results from the Irish Sea and the Kara Sea will be discussed

Covalent immobilization of penicillin G acylase on aminopropyl-functionalized mesostructured cellular foams.

Science.gov (United States)

Zhao, Junqi; Wang, Yujun; Luo, Guangsheng; Zhu, Shenlin

2010-10-01

Mesostructured cellular foams (MCFs) are suitable for biomolecular immobilization because of their relatively large-pore diameter and pore volume. Penicillin G acylase (PGA) was immobilized on aminopropyl-functionalized MCFs through Schiff base reaction. It is shown that PGA could be fixed more firmly through the covalent immobilization on aminopropyl-functionalized MCFs support than through the adsorption immobilization on blank MCFs. The PGA loading amount on the aminopropyl-functionalized MCFs could reach 443 mg/g (dry support), and the apparent activity could achieve up to 4138 U/g (dry support). The influence of the amount of grafted aminopropyl group was studied, and it is found that the optimal molar ratio of MCFs to APTS was 15/1; in addition, the suitable enzyme distribution density for the specific activity of the immobilized PGA was 0.7 mg enzyme per m(2) of specific area of MCFs. Copyright 2010 Elsevier Ltd. All rights reserved.

Balanced sediment fluxes in southern California’s Mediterranean-climate zone salt marshes

Science.gov (United States)

Rosencranz, Jordan A.; Ganju, Neil K.; Ambrose, Richard F.; Brosnahan, Sandra M.; Dickhudt, Patrick J.; Guntenspergen, Glenn R.; MacDonald, Glen M.; Takekawa, John Y.; Thorne, Karen M.

2016-01-01

Salt marsh elevation and geomorphic stability depends on mineral sedimentation. Many Mediterranean-climate salt marshes along southern California, USA coast import sediment during El Niño storm events, but sediment fluxes and mechanisms during dry weather are potentially important for marsh stability. We calculated tidal creek sediment fluxes within a highly modified, sediment-starved, 1.5-km2 salt marsh (Seal Beach) and a less modified 1-km2marsh (Mugu) with fluvial sediment supply. We measured salt marsh plain suspended sediment concentration and vertical accretion using single stage samplers and marker horizons. At Seal Beach, a 2014 storm yielded 39 and 28 g/s mean sediment fluxes and imported 12,000 and 8800 kg in a western and eastern channel. Western channel storm imports offset 8700 kg exported during 2 months of dry weather, while eastern channel storm imports augmented 9200 kg imported during dry weather. During the storm at Mugu, suspended sediment concentrations on the marsh plain increased by a factor of four; accretion was 1–2 mm near creek levees. An exceptionally high tide sequence yielded 4.4 g/s mean sediment flux, importing 1700 kg: 20 % of Mugu’s dry weather fluxes. Overall, low sediment fluxes were observed, suggesting that these salt marshes are geomorphically stable during dry weather conditions. Results suggest storms and high lunar tides may play large roles, importing sediment and maintaining dry weather sediment flux balances for southern California salt marshes. However, under future climate change and sea level rise scenarios, results suggest that balanced sediment fluxes lead to marsh elevational instability based on estimated mineral sediment deficits.

Distribution and abundance of archaeal and bacterial ammonia oxidizers in the sediments of the Dongjiang River, a drinking water supply for Hong Kong.

Science.gov (United States)

Sun, Wei; Xia, Chunyu; Xu, Meiying; Guo, Jun; Wang, Aijie; Sun, Guoping

2013-01-01

Ammonia-oxidizing archaea (AOA) and bacteria (AOB) play important roles in nitrification. However, limited information about the characteristics of AOA and AOB in the river ecosystem is available. The distribution and abundance of AOA and AOB in the sediments of the Dongjiang River, a drinking water source for Hong Kong, were investigated by clone library analysis and quantitative real-time PCR. Phylogenetic analysis showed that Group 1.1b- and Group 1.1b-associated sequences of AOA predominated in sediments with comparatively high carbon and nitrogen contents (e.g. total carbon (TC) >13 g kg(-1) sediment, NH4(+)-N >144 mg kg(-1) sediment), while Group 1.1a- and Group 1.1a-associated sequences were dominant in sediments with opposite conditions (e.g. TC <4 g kg(-1) sediment, NH4(+)-N <93 mg kg(-1) sediment). Although Nitrosomonas- and Nitrosospira-related sequences of AOB were detected in the sediments, nearly 70% of the sequences fell into the Nitrosomonas-like B cluster, suggesting similar sediment AOB communities along the river. Higher abundance of AOB than AOA was observed in almost all of the sediments in the Dongjiang River, while significant correlations were only detected between the distribution of AOA and the sediment pH and TC, which suggested that AOA responded more sensitively than AOB to variations of environmental factors. These results extend our knowledge about the environmental responses of ammonia oxidizers in the river ecosystem.

Distribution of butyltins in the waters and sediments along the coast of India

Digital Repository Service at National Institute of Oceanography (India)

Garg, A.; Meena, R; Jadhav, S.; Bhosle, N.B.

for sediments it varied between below detection limit to 14861 ng Sn g sup(-1) dry weight of sediment. On an average Chennai port recorded the highest level of butyltins in the sediments while Paradip recorded the highest level of butylins in the waters. A...

Polycyclic aromatic hydrocarbons in sediments and mussels of Corral Bay, south central Chile.

Science.gov (United States)

Palma-Fleming, Hernan; P, Adalberto J Asencio; Gutierrez, Elena

2004-03-01

PAHs were measured in sediments and mussels (Mytilus chilensis) from Carboneros and Puerto Claro, located in Corral Bay, Valdivia. According to the ratio of phenanthrene/anthracene and fluoranthene/pyrene concentrations, these sites are medium polluted with PAHs originating mainly from pyrolytic sources. Fluoranthene was the major component measured in mussels (3.1-390 ng g(-1) dry weight) and sediments (6.9-74.1 ng g(-1) dry weight). In general, mussels were mainly exposed to the dissolved fraction of the lower molecular weight PAHs (tri- and tetra-aromatics) while the higher molecular ring systems (penta- and hexa-aromatics) were more bioavailable to sediments. Mussel PAHs content was relatively constant, with the exception of the 1999 summer season (March), when higher concentration values were found in both sites; however, PAHs residues in sediments showed a temporal variation.

Development of a sample preparation method for the analysis of current-use pesticides in sediment using gas chromatography.

Science.gov (United States)

Wang, Dongli; Weston, Donald P; Ding, Yuping; Lydy, Michael J

2010-02-01

Pyrethroid insecticides have been implicated as the cause of sediment toxicity to Hyalella azteca in both agricultural and urban areas of California; however, for a subset of these toxic sediments (approximately 30%), the cause of toxicity remains unidentified. This article describes the analytical method development for seven additional pesticides that are being examined to determine if they might play a role in the unexplained toxicity. A pressurized liquid extraction method was optimized to simultaneously extract diazinon, methyl parathion, oxyfluorfen, dicofol, fenpropathrin, pyraclostrobin, and indoxacarb from sediment, and the extracts were cleaned using a two-step solid-phase extraction procedure. The final extract was analyzed for the target pesticides by gas chromatography/nitrogen-phosphorus detector (GC/NPD), and gas chromatography/electron capture detector (GC/ECD), after sulfur was removed by shaking with copper and cold crystallization. Three sediments were used as reference matrices to assess method accuracy and precision. Method detection limits were 0.23-1.8 ng/g dry sediment using seven replicates of sediment spiked at 1.0 ng/g dry sediment. Recoveries ranged from 61.6 to 118% with relative standard deviations of 2.1-17% when spiked at 5.0 and 50 ng/g dry sediment. The three reference sediments, spiked with 50 ng/g dry weight of the pesticide mixture, were aged for 0.25, 1, 4, 7, and 14 days. Recoveries of the pesticides in the sediments generally decreased with increased aging time, but the magnitude of the decline was pesticide and sediment dependent. The developed method was applied to field-collected sediments from the Central Valley of California.

PAHs concentration and toxicity in organic solvent extracts of atmospheric particulate matter and sea sediments.

Science.gov (United States)

Ozaki, Noriatsu; Takeuchi, Shin-ya; Kojima, Keisuke; Kindaichi, Tomonori; Komatsu, Toshiko; Fukushima, Takehiko

2012-01-01

The concentration of polycyclic aromatic hydrocarbons (PAHs) and the toxicity to marine bacteria (Vibrio fischeri) were measured for the organic solvent extracts of sea sediments collected from an urban watershed area (Hiroshima Bay) of Japan and compared with the concentrations and toxicity of atmospheric particulate matter (PM). In atmospheric PM, the PAHs concentration was highest in fine particulate matter (FPM) collected during cold seasons. The concentrations of sea sediments were 0.01-0.001 times those of atmospheric PM. 1/EC50 was 1-10 L g(-1) PM for atmospheric PM and 0.1-1 L g(-1) dry solids for sea sediments. These results imply that toxic substances from atmospheric PM are diluted several tens or hundreds of times in sea sediments. The ratio of the 1/EC50 to PAHs concentration ((1/EC50)/16PAHs) was stable for all sea sediments (0.1-1 L μg(-1) 16PAHs) and was the same order of magnitude as that of FPM and coarse particulate matter (CPM). The ratio of sediments collected from the west was more similar to that of CPM while that from the east was more similar to FPM, possibly because of hydraulic differences among water bodies. The PAHs concentration pattern analyses (principal component analysis and isomer ratio analysis) were conducted and the results showed that the PAHs pattern in sea sediments was quite different to that of FPM and CPM. Comparison with previously conducted PAHs analyses suggested that biomass burning residues comprised a major portion of these other sources.

Problems of Gas Pressure Build-up in Casing String of UGS and Gas Wells

Directory of Open Access Journals (Sweden)

Peter Sovius

2006-10-01

Full Text Available This paper consists of three basic parts. The opening part is a brief description of problems associated with the secondary untightness of UGS wells (Underground Gas Storages and gas wells generally.The main part of the paper is composed of some cases that we have met in our company. Solution proposals of various cases are also supplied in this part. Separate problem situations are described in terms of finding out an untight point and also a testing result and consequential removing of untightness.The conclusion includes knowledge summary that were taken by solution of complicatedsituations connected with well non-hermeticity.

Association of glucose-6-phosphate dehydrogenase deficiency and X-linked chronic granulomatous disease in a child with anemia and recurrent infections

OpenAIRE

Agudelo-Florez, P.; Costa-Carvalho, Beatriz Tavares [UNIFESP; Lopez, J. A.; Redher, J.; Newburger, P. E.; Alla-Saad, S. T.; Condino-Neto, A.

2004-01-01

Patients with severe leukocyte G6PD deficiency may present with impairment of NADPH oxidase activity and a history of recurrent infections, mimicking the phenotype of chronic granulomatous disease. We report herein a child with recurrent infections who initially received the diagnosis of G6PD deficiency. His erythrocyte G6PD activity was reduced: 1.8 U/g Hb (normal: 12.1 +/- 2.1 U/g Hb). Further studies revealed that G6PD activity in neutrophils, mononuclear leukocytes, and Epstein-Barr virus...

The concentration of cadmium in hepatoma among Filipinos

International Nuclear Information System (INIS)

Alejandrino, A.L.; Goze, C.B.; Paradero, R.R.

1977-08-01

The concentration of cadmium in liver hepatoma and in normal liver in Filipinos was determined by atomic absorption spectrophotometry. Using NBS Bovine Liver (SRM1577) as reference material, a value of 0.28+-0.025 ug/g dry weight was obtained for cadmium which is close to the certified NBS value of 0.27+-0.04 ug/g. The mean percentage recovery for cadmium determination by AAS was 98.38%. A mean value of 2.14+-1.58 ug Cd/g liver hepatoma was observed for the 12 cases investigated, showing decreased cadmium levels in the cancerous liver compared to the mean value of 12.62 ug Cd/g observed for normal liver obtained from 10 cases of accidental deaths. The values are expressed on a dry weight basis

Tributyltin distribution and producing androgenic activity in water, sediment, and fish muscle.

Science.gov (United States)

Shue, Meei-Fang; Chen, Ting-Chien; Bellotindos, Luzvisminda M; Lu, Ming-Chun

2014-01-01

This study investigated the concentrations of Tributyltin (TBT) in water, sediment, and fish muscle samples taken from Kaohsiung Harbor and Kaoping River estuary, Taiwan. TBT concentrations in water and sediment samples ranged from less than 18.5 to 34.1 ng Sn L(-1) and from 2.44 to 29.7 ng Sn g(-1) weight per weight (w/w), respectively. Concentrations in the TBT-contaminated fish muscle samples ranged from 10.8 to 79.6 ng Sn g(-1) w/w. The TBT concentrations in fish muscle were higher than those in water and sediment samples. The fish muscle/water TBT bioconcentration factor (BCF) ranged from 590 to 3363 L kg(-1). Additionally, the water samples were assessed for androgenic activity with an MCF7-AR1 human breast cancer cell line. The androgenic activity ranged from 0.94 to 3.1 ng-dihydrotestosterone per litre water (ng-DHT L(-1)). Higher concentrations of TBT in water and sediment samples occurred in the dry season, but the androgenic activity had higher values in the rainy season.

Pesticide sorption by low organic carbon sediments: A sceening for seven herbicides

DEFF Research Database (Denmark)

Madsen, Lene; Lindhardt, Bo; Rosenberg, Per

2000-01-01

The sorption of seven pesticides in 10 Danish aquifer sediments has been studied. These sediments all have a total organic carbon (TOC) content below 1 g kg(-1), and include carbonate-bearing and carbonate-free Quatenary sand deposits and a Cretaceous chalk aquifer. Batch experiments were carried...

Spatial distributions and temporal trends in polybrominated diphenyl ethers in Detroit River suspended sediments.

Science.gov (United States)

Marvin, Chris; Waltho, Jasmine; Jia, Julia; Burniston, Debbie

2013-05-01

Suspended sediments from the Detroit River were collected using sediment traps at sites ranging from western Lake Erie to southern Lake St. Clair to assess spatial distributions and temporal trends of polybrominated diphenyl ethers (PBDEs). The distribution of PBDEs in suspended sediments in the Detroit River appeared influenced by shoreline-based contemporary urban and industrial activities, which stood in contrast to PCBs that were associated with areas of historic industrial activity. Temporal trend data indicate that total PBDE concentrations decreased in the period after 2000 in response to cessation of production of the penta- and octa BDE formulations. Concentrations of total PBDEs ranged from roughly 7 ng g(-1) (4 ng g(-1) BDE 209) in southern Lake St. Clair to several hundred ng g(-1) (60-180 ng g(-1) BDE 209) in the lower reaches of the Detroit River. The widespread occurrence of PBDEs in Detroit River suspended sediments suggests that large urban areas can act as diffuse sources of these chemicals that are used in modern industrial applications and consumer products. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Antifoulant (butyltin and copper) concentrations in sediments from the Great Barrier Reef World Heritage Area, Australia

International Nuclear Information System (INIS)

Haynes, David; Loong, Dominica

2002-01-01

Antifoulant concentrations are generally low in the Great Barrier Reef, although ship grounding sites present a previously unidentified significant source of antifoulant pollutants in the Great Barrier Reef. - Antifoulant concentrations were determined in marine sediments collected from commercial harbours, marinas, mooring locations on mid-shelf continental islands, and outer reef sites in four regions within the Great Barrier Reef World Heritage Area in 1999. Highest copper concentrations were present in sediments collected from commercial harbour sampling sites (28-233 μg Cu g -1 dry wt.). In contrast, copper concentrations in sediments collected from boat mooring sites on mid-shelf continental islands and outer reef sites were at background concentrations (i.e. -1 dry wt.). Butyltin was only detectable in four of the 42 sediments sampled for analysis, and was only present in sediments collected from commercial harbours (18-1275 ng Sn g -1 dry wt.) and from marinas (4-5 ng Sn g -1 dry wt.). The detection of tributyltin at marina sites implies that this antifoulant may continue to be used illegally on the hulls of smaller recreational vessels. Sediment samples were also collected opportunistically from the site of a 22,000 t cargo ship grounding in May 1999 at Heath Reef, in the far northern Great Barrier Reef. Butyltin concentrations were grossly elevated (660-340,000 ng Sn g -1 dry wt.) at the grounding site. The impact of residual antifoulants at large ship grounding sites should be recognised as a significant, long-term environmental problem unless antfoulant clean-up strategies are undertaken

Trace element distributions in aquatic sediments of Danang - Hoian area, Vietnam

Energy Technology Data Exchange (ETDEWEB)

Thuy, H.T.T.; Tobschall, H.J. [Erlangen-Nuernberg Univ., Erlangen (Germany). Inst. fuer Geologie und Mineralogie; An, P.V. [University of Mining and Geology, Hanoi (Viet Nam)

2000-05-01

Distribution of the trace elements Cr, Cu, Ni, Pb and Zn in surficial sediments of the river/sea environment in Danang - Hoian area (Vietnam) was investigated to examine the degree of metal pollution caused by anthropogenic activities. Point sources from domestic and industrial wastes are identified as dominant contributors of trace element accumulation. Surficial sediments of Hoian River show extremely high total concentrations of Cu (Average Concentration 295 {mu}g/g), Ni (AC 112 {mu}g/g), Pb (AC 396 {mu}g/g) and Zn (AC 429 mug/g) that exceed assigned safety levels ER-M. Similarly, the sediments of Han River show high Pb (AC 188 {mu}g/g) and Zn (AC 282 {mu}g/g) contents. In marine sediments of Thanhbinh beach Pb is also enriched (138 {mu}g/g) above guideline levels. In contrast the sediments of the Cude River are dominated by trace element concentrations close to background values. (orig.)

Sediment dynamics in Alpine basins

Science.gov (United States)

Habersack, Helmut; Liébault, Fred; Comiti, Francesco

2017-08-01

In rivers and streams and of the European Alps, sediment transport processes are of great relevance due to their ecological (e.g. aquatic habitats), energy (e.g. reservoir sedimentation) and risk-related (floods and debris flows) consequences. In fact, sediment fluxes are crucial to maintain a good ecological status of watercourses (required by the EU ;Water Framework Directive;, WFD, 2000), as they provide the hydromorphological conditions supporting dynamic aquatic ecosystems (Fryirs and Brierley, 2013; Wohl et al., 2015; Gurnell et al., 2016). Indeed, the key issue to ameliorate river hydrogeomorphological - and thus ecological - status and to comply with WFD provisions lies in allowing the natural processes of sediment and wood supply and transport to take place as much as possible, given the constraints imposed by the non-eliminable uses of each river (Comiti, 2012; Liébault et al., 2013). Specifically river continuity is mentioned in the WFD not only for biota but also sediments, which is hardly discussed in river management so far and almost no concrete measures to improve sediment continuity have been implemented so far (Habersack et al., 2016).

Urinary continence following repair of intermediate and high urogenital sinus in CAH. Experience with 55 cases.

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Maria Marcela Bailez

2014-07-01

Full Text Available Aim :Evaluate postoperative urinary continence in patients withcongenital adrenal hyperplasia(CAHwith intermediate (ITand high urogenital sinus (UGS who underwent a UGS mobilization maneuver .Methods: We called IT to those that although needing an aggressive dissection to get to the vagina, still have enough urethra proximal to the vaginal confluence. Very low variants are excluded from this analysis. Dissection always started in the posterior wall of the UGS with an aggressive separation from the anterior rectal wall. If the wide portion of the vagina was reached dissection stopped and the UGS opened ventrally widening to the introitus. Nineteen patients were treated using this maneuver (Group1. When more dissection was required the anterior wall of the UGS was dissected and carefully freed from the low retropubic space. Then the UGS was opened either ventrally or dorsally. Thirty three patients required this approach (Group 2 .Combined procedures were used in 3 patients with high UGS (Group 3. Results : Mean age at the time of the repair and length of the UGS were 12.2 years (4 months to 18 years and 3.75 cm (3 -8 cmfor G 1; 8 years (5 months to 17 years and 6.34 cm ( 4-12 cm in G2 and 8,3 years (2 -14 y and 11.5cm (11-12cm in G3. All patients had been regularly followed. Mean age at last follow up of 14.3y, 17y and 9.9y for groups 1, 2 and 3 respectively. All patients continue to void normally and are continent. All patients have 2 separate visible orifices in the vulva. Only 3 are sexually active.Conclusion: UGS mobilization for vaginoplasty in girls with CAH does not compromise voiding function or urinary continence,

Evaluación del efecto del ácido nalidíxico, ampicilina, kanamicina, penicilina G y polimixina B en los cultivos de promastigotes de leishmania

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Sofía Duque Beltrán

1992-06-01

Full Text Available Se evaluó el efecto de diferentes concentraciones de ácido nalidíxico, ampicilina, kanarnicina, penicilina G y polimixina B, sobre la población de promastigotes de Leishmania braziliensis braziliensis , Leishmania donovani chagasi y Leishmania mexicana amazonensis in vitro. La penicilina G y la ampicilina se pueden utilizar hasta concentraciones de 1000 ug/ml y 500 ug/ml respectivamente en cultivo de promastigotes de cualquier cepa de Leishmania sin que éstos se afecten. La polimixina B disminuye la población de prosmastigotes por lo cual es preferible no usarse en cultivos de Leishmania. El ácido nalidíxico y kanamicina pueden ser utilizados in vitro pero teniéndose en cuenta la especie de Leishmania y la concentración de anfimicrobiano recomendado para la misma.

Effects of the antibiotic ciprofloxacin on the bacterial community structure and degradation of pyrene in marine sediment

International Nuclear Information System (INIS)

Naeslund, Johan; Hedman, Jenny E.; Agestrand, Cecilia

2008-01-01

The ecological consequences of antibiotics in the aquatic environment have been an issue of concern over the past years due to the potential risk for negative effects on indigenous microorganisms. Microorganisms provide important ecosystem services, such as nutrient recycling, organic matter mineralization and degradation of pollutants. In this study, effects of exposure to the antibiotic ciprofloxacin on the bacterial diversity and pollutant degradation in natural marine sediments were studied using molecular methods (T-RFLP) in combination with radiorespirometry. In a microcosm experiment, sediment spiked with 14 C-labelled pyrene was exposed to five concentrations of ciprofloxacin (0, 20, 200, 1000 and 2000 μg L -1 ) in a single dose to the overlying water. The production of 14 CO 2 (i.e. complete mineralization of pyrene) was measured during 11 weeks. Sediment samples for bacterial community structure analysis were taken after 7 weeks. Results showed a significant dose-dependent inhibition of pyrene mineralization measured as the total 14 CO 2 production. The nominal EC 50 was calculated to 560 μg L -1 , corresponding to 0.4 μg/kg d.w. sediment. The lowest effect concentration on the bacterial community structure was 200 μg L -1 , which corresponds to 0.1 μg/kg d.w. sediment. Our results show that antibiotic pollution can be a potential threat to both bacterial diversity and an essential ecosystem service they perform in marine sediment

Mercury, zinc, and copper accumulation in mangrove sediments surrounding a large landfill in southeast Brazil

Energy Technology Data Exchange (ETDEWEB)

Machado, W.; Moscatelli, M.; Rezende, L.G.; Lacerda, L.D

2002-12-01

Mangrove sediments may prevent movement of metals to adjacent bodies of water. - The accumulation of Hg, Zn, and Cu was evaluated in mangrove sediments located between a large, 20-years-old landfill and waters of Guanabara Bay (southeast Brazil). The contamination history of the area provides substantial evidence that metal accumulation in the study site is influenced by past metal emissions from multiple sources (e.g. contaminated rivers and the landfill surrounding the site). At the southern part of the site, metal levels are up to 890 ng g{sup -1} Hg, 850 {mu}g g{sup -1} Zn, and 58 {mu}g g{sup -1} Cu. Enrichment factors and excess (background-deducted) concentration inventories show a high spatial variability of metal contamination and storage in the site, with differences often by a factor higher than two within a sampling station and higher than five between sampling stations. These contrasts are attributable to a coupling between spatial variability of anthropogenic metal input and metal behavior and retention within the sediments. Results indicate that during the last few decades mangrove sediments retained a substantial part of metal emissions to the site, probably reducing the metal transport to Guanabara Bay waters, and suggest the suitability of mangrove ecosystems as physical and biogeochemical barriers to metal contaminant transport.

Mercury, zinc, and copper accumulation in mangrove sediments surrounding a large landfill in southeast Brazil

International Nuclear Information System (INIS)

Machado, W.; Moscatelli, M.; Rezende, L.G.; Lacerda, L.D.

2002-01-01

Mangrove sediments may prevent movement of metals to adjacent bodies of water. - The accumulation of Hg, Zn, and Cu was evaluated in mangrove sediments located between a large, 20-years-old landfill and waters of Guanabara Bay (southeast Brazil). The contamination history of the area provides substantial evidence that metal accumulation in the study site is influenced by past metal emissions from multiple sources (e.g. contaminated rivers and the landfill surrounding the site). At the southern part of the site, metal levels are up to 890 ng g -1 Hg, 850 μg g -1 Zn, and 58 μg g -1 Cu. Enrichment factors and excess (background-deducted) concentration inventories show a high spatial variability of metal contamination and storage in the site, with differences often by a factor higher than two within a sampling station and higher than five between sampling stations. These contrasts are attributable to a coupling between spatial variability of anthropogenic metal input and metal behavior and retention within the sediments. Results indicate that during the last few decades mangrove sediments retained a substantial part of metal emissions to the site, probably reducing the metal transport to Guanabara Bay waters, and suggest the suitability of mangrove ecosystems as physical and biogeochemical barriers to metal contaminant transport

Watershed sediment losses to lakes accelerating despite agricultural soil conservation efforts.

Science.gov (United States)

Heathcote, Adam J; Filstrup, Christopher T; Downing, John A

2013-01-01

Agricultural soil loss and deposition in aquatic ecosystems is a problem that impairs water quality worldwide and is costly to agriculture and food supplies. In the US, for example, billions of dollars have subsidized soil and water conservation practices in agricultural landscapes over the past decades. We used paleolimnological methods to reconstruct trends in sedimentation related to human-induced landscape change in 32 lakes in the intensively agricultural region of the Midwestern United States. Despite erosion control efforts, we found accelerating increases in sediment deposition from erosion; median erosion loss since 1800 has been 15.4 tons ha(-1). Sediment deposition from erosion increased >6-fold, from 149 g m(-2) yr(-1) in 1850 to 986 g m(-2) yr(-1) by 2010. Average time to accumulate one mm of sediment decreased from 631 days before European settlement (ca. 1850) to 59 days mm(-1) at present. Most of this sediment was deposited in the last 50 years and is related to agricultural intensification rather than land clearance or predominance of agricultural lands. In the face of these intensive agricultural practices, traditional soil conservation programs have not decelerated downstream losses. Despite large erosion control subsidies, erosion and declining water quality continue, thus new approaches are needed to mitigate erosion and water degradation.

Mapping resistance to the Ug99 race group of the stem rust pathogen in a spring wheat landrace.

Science.gov (United States)

Babiker, E M; Gordon, T C; Chao, S; Newcomb, M; Rouse, M N; Jin, Y; Wanyera, R; Acevedo, M; Brown-Guedira, G; Williamson, S; Bonman, J M

2015-04-01

A new gene for Ug99 resistance from wheat landrace PI 374670 was detected on the long arm of chromosome 7A. Wheat landrace PI 374670 has seedling and field resistance to stem rust caused by Puccinia graminis f. sp tritici Eriks. & E. Henn (Pgt) race TTKSK. To elucidate the inheritance of resistance, 216 BC1F2 families, 192 double haploid (DH) lines, and 185 recombinant inbred lines (RILs) were developed by crossing PI 374670 and the susceptible line LMPG-6. The parents and progeny were evaluated for seedling resistance to Pgt races TTKSK, MCCFC, and TPMKC. The DH lines were tested in field stem rust nurseries in Kenya and Ethiopia. The DH lines were genotyped with the 90K wheat iSelect SNP genotyping platform. Goodness-of-fit tests indicated that a single dominant gene in PI 374670 conditioned seedling resistance to the three Pgt races. The seedling resistance locus mapped to the long arm of chromosome 7A and this result was verified in the RIL population screened with the flanking SNP markers using KASP assays. In the same region, a major QTL for field resistance was detected in a 7.7 cM interval and explained 34-54 and 29-36% of the variation in Kenya and Ethiopia, respectively. Results from tests with specific Pgt races and the csIH81 marker showed that the resistance was not due to Sr22. Thus, a new stem rust resistance gene or allele, either closely linked or allelic to Sr15, is responsible for the seedling and field resistance of PI 374670 to Ug99.

Phosphorus fractions and its potential release in the sediments of Koycegiz Lake, Turkey

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Yalçın Şahin

2012-12-01

Full Text Available This study was conducted to find out the seasonal and spatial patterns of the phosphorus in the littoral sediment and its potential release into the Koycegiz Lake, south west Turkey, between November 2011 and March 2012 at two months intervals. The scanning electron microscopy was used for elemental compositions of the sediment. The amounts and forms of phosphorus (P in surface sediments of Koycegiz Lake were examined using a not sequential chemical extraction procedure. Four fractions of sedimentary P, including organic bound phosphorus fraction (Org≈P, calcium bound phosphorus fraction (Ca≈P, iron+aluminium bound phosphorus fraction (Fe+Al≈P and carbonate bound phosphorus fraction (CO3≈P were separately quantified. The results indicated that the contents of different phosphorus fractions in the sediments varied greatly. The proportion of phosphorus fractions was estimated as Org≈P (90.20 %, this fraction was followed by Ca≈P (9.06 %, Fe+Al≈P (0.47 % and CO3≈P (0.27 % in this study. The level of phosphorus release from the sediment to the lake is calculated as low. The sediment phosphorus release fluctuated between -6.647–75.883 μg/m2.d-1 and the total phosphorus (TP concentrations of the sediment samples were changed between 980.39 μg/gDW (Dry Weight - 1990.81 μg/gDW. The results show that it can be evaluation as eutrophic for Koycegiz Lake.

The effect of river pulsing on sedimentation and nutrients in created riparian wetlands.

Science.gov (United States)

Nahlik, Amanda M; Mitsch, William J

2008-01-01

Sedimentation under pulsed and steady-flow conditions was investigated in two created flow-through riparian wetlands in central Ohio over 2 yr. Hydrologic pulses of river water lasting for 6 to 8 d were imposed on each wetland from January through June during 2004. Mean inflow rates during pulses averaged 52 and 7 cm d(-1) between pulses. In 2005, the wetlands received a steady-flow regime of 11 cm d(-1) with no major hydrologic fluctuations. Thirty-two sediment traps were deployed and sampled once per month in April, May, June, and July for two consecutive years in each wetland. January through March were not sampled in either year due to frozen water surfaces in the wetlands. Gross sedimentation (sedimentation without normalizing for differences between years) was significantly greater in the pulsing study period (90 kg m(-2)) than in the steady-flow study period (64 kg m(-2)). When normalized for different hydrologic and total suspended solid inputs between years, sedimentation for April through July was not significantly different between pulsing and steady-flow study periods. Sedimentation for the 3 mo that received hydrologic pulses (April, May, and June) was significantly lower during pulsing months than in the corresponding steady-flow months. Large fractions of inorganic matter in collected sediments indicated that allochthonous inputs were the main contributor to sedimentation in these wetlands. Organic matter fractions of collected sediments were consistently greater in the steady-flow study period (1.8 g kg(-1)) than in the pulsed study period (1.5 g kg(-1)), consistent with greater primary productivity in the water column during steady-flow conditions.

Dicty_cDB: Contig-U04426-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available MMBB... 32 2.9 5 ( AC174151 ) Homo sapiens chromosome 4 clone WI2-1953O14, comp... 42 2.9 2 ( CD147127 ) ML1...1-734E9, WORKI... 42 2.8 3 ( CC262481 ) CH261-167M9_Sp6.1 CH261 Gallus gallus gen...omic clo... 32 2.8 3 ( CD147117 ) ML1-0002T-M115-B10-U.G ML1-0002 Schistosoma manso... 38 2.8 2 ( BX842699 )

Excess unsupported sup(210)Pb in lake sediment from Rocky Mountain lakes

International Nuclear Information System (INIS)

Norton, S.A.; Hess, C.T.; Blake, G.M.; Morrison, M.L.; Baron, J.

1985-01-01

Sediment cores from four high-altitude (approximately 3200 m) lakes in Rocky Mountain National Park, Colorado, were dated by sup(210)Pb chronology. Background (supported) sup(210)Pb activities for the four cores range from 0.26 to 0.93 Beq/g dry weight, high for typical oligotrophic lakes. Integrated unsupported sup(210)Pb ranges from 0.81 (a typical value for most lakes) to 11.0 Beq/cmsup(2). The sup(210)Pb activity in the surface sediments ranges from 1.48 to 22.2 Beq/g dry weight. Sedimentation from Lake Louise, the most unusual of the four, has 22.2 Beq/g dry weight at the sediment surface, an integrated unsupported sup(210)Pb=11.0 Beq/cmsup(2), and supported sup(210)Pb=0.74 Beq/g dry weight. sup(226)Ra content of the sediment is insufficient to explain either the high unsupported sup(210)Pb or the sup(222)Rn content of the water column of Lake Louise, which averaged 96.2 Beq/L. We concluded that sup(222)Rn-rich groundwater entering the lake is the source of the high sup(222)Rn in the water column. This, in turn, is capable of supporting the unusually high sup(210)Pb flux to the sediment surface. Groundwater with high sup(222)Rn may control the sup(210)Pb budget of lakes where sediment cores have integrated unsupported sup(210)Pb greater than 2 Beq/cmsup(2)

The Effect of Nitrogen Enrichment on C1-Cycling Microorganisms and Methane Flux in Salt Marsh Sediments

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Irina Catherine Irvine

2012-03-01

Full Text Available Methane (CH4 flux from ecosystems is driven by C1-cycling microorganisms – the methanogens and the methylotrophs. Little is understood about what regulates these communities, complicating predictions about how global change drivers such as nitrogen enrichment will affect methane cycling. Using a nitrogen addition gradient experiment in three Southern California salt marshes, we show that sediment CH4 flux increased linearly with increasing nitrogen addition (1.23 µg CH4 m-2 d-1 for each g N m-2 yr-1 applied after seven months of fertilization. To test the reason behind this increased CH4 flux, we conducted a microcosm experiment altering both nitrogen and carbon availability under aerobic and anaerobic conditions. Methanogenesis appeared to be both nitrogen and carbon (acetate limited. N and C each increased methanogenesis by 18%, and together by 44%. In contrast, methanotrophy was stimulated by carbon (methane addition (830%, but was unchanged by nitrogen addition. Sequence analysis of the sediment methylotroph community with the methanol dehydrogenase gene (mxaF revealed three distinct clades that fall outside of known lineages. However, in agreement with the microcosm results, methylotroph abundance (assayed by qPCR and composition (assayed by T-RFLP did not vary across the experimental nitrogen gradient in the field. Together, these results suggest that nitrogen enrichment to salt marsh sediments increases methane flux by stimulating the methanogen community.

Characterization of sediment trapped by macroalgae on a Hawaiian reef flat

Science.gov (United States)

Stamski, Rebecca E.; Field, Michael E.

2006-01-01

Reef researchers studying community shifts in the balance between corals and fleshy macroalgae have noted that algae are often covered with sediment. This study characterizes sediment trapping by macroalgae within a Hawaiian reef habitat and constrains the controls on this process. Sediment-laden macroalgae were sampled and macroalgal cover was assessed on a wide (˜1 km) reef flat off south-central Molokai. Macroalgae trapped a mean of 1.26 (±0.91 SD) grams of sediment per gram of dry weight biomass and that sediment was dominantly terrigenous mud (59% by weight). It was determined that biomass, as a proxy for algal size, and morphology were not strict controls on the sediment trapping process. Over 300 metric tons of sediment were estimated to be retained by macroalgae across 5.75 km 2 of reef flat (54 g m -2), suggesting that this process is an important component of sediment budgets. In addition, understanding the character of sediment trapped by macroalgae may help constrain suspended sediment flux and has implications for nutrient dynamics in reef flat environments.

The MAP, M/G1,G2/1 queue with preemptive priority

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Bong Dae Choi

1997-01-01

Full Text Available We consider the MAP, M/G1,G2/1 queue with preemptive resume priority, where low priority customers arrive to the system according to a Markovian arrival process (MAP and high priority customers according to a Poisson process. The service time density function of low (respectively: high priority customers is g1(x (respectively: g2(x. We use the supplementary variable method with Extended Laplace Transforms to obtain the joint transform of the number of customers in each priority queue, as well as the remaining service time for the customer in service in the steady state. We also derive the probability generating function for the number of customers of low (respectively, high priority in the system just after the service completion epochs for customers of low (respectively, high priority.

Pectinase production by Penicillium viridicatum RFC3 by solid state fermentation using agricultural wastes and agro-industrial by-products

Directory of Open Access Journals (Sweden)

Silva Dênis

2002-01-01

Full Text Available Pectin lyase and polygalacturonase production by newly isolated Penicillium viridicatum strain Rfc3 was carried out by means of solid state fermentation using orange bagasse, corn tegument, wheat bran and mango and banana peels as carbon sources. The maximal activity value of polygalacturonase (Pg (30U.g-1 was obtained using wheat bran as carbon source while maximal pectin lyase (Pl (2000 U.g-1 activity value was obtained in medium composed of orange bagasse. Mixtures of banana or mango peels with sugar cane bagasse resulted in increased Pg and Pl production compared to fermentations in which this residue was not used. The mixture of orange bagasse and wheat bran (50% increased the production of Pg and Pl to 55 U.g-1 and 3540 U.g -1 respectively. Fractions of Pg and Pl, isolated by gel filtration in Sephadex G50, presented optimum activity at pH 5.0 and 10.5 respectively. Maximal activity of Pg and Pl fractions was determined at 55ºC and 50ºC respectively. Pg was stable in neutral pH range and at 40ºC whereas Pl was stable in acidic pH and at 35ºC, for 1 h.

Wind-enhanced resuspension in the shallow waters of South San Francisco Bay: Mechanisms and potential implications for cohesive sediment transport

Science.gov (United States)

Brand, Andreas; Lacy, Jessica R.; Hsu, Kevin; Hoover, Daniel; Gladding, Steve; Stacey, Mark T.

2010-01-01

We investigated the driving forces of sediment dynamics at the shoals in South San Francisco Bay. Two stations were deployed along a line perpendicular to a 14 m deep channel, 1000 and 2000 m from the middle of the channel. Station depths were 2.59 and 2.19 m below mean lower low water, respectively. We used acoustic Doppler velocimeters for the simultaneous determination of current velocities, turbulence, sediment concentration and fluxes. Maximum current shear velocities were 0.015 m s−1 at the station further from the channel (closer to the shore) and 0.02 m s−1 at the station closer to the channel. Peak wave-induced shear velocities exceeded 0.015 m s−1 at both stations. Maximum sediment concentrations were around 30 g m−3 during calm periods (root mean square wave height −3 and sediment fluxes were 5 times higher than in calm conditions (0.02 g m−2 s−1 versus >0.10 g m−2 s−1) at the station further from the channel 0.36 m above the bed. Closer to the channel, sediment concentrations and vertical fluxes due to wind wave resuspension were persistently lower (maximum concentrations around 50 g m−3 and maximum fluxes around 0.04 g m−2 s−1). Most resuspension events occurred during flood tides that followed wave events during low water. Although wave motions are able to resuspend sediment into the wave boundary layer at low tide, the observed large increases in sediment fluxes are due to the nonlinear interaction of wind waves and the tidal currents.

Wpływ informatyzacji Biblioteki Uniwersyteckiej w Poznaniu na zmiany organizacyjne i rozwój usług bibliotecznych

Directory of Open Access Journals (Sweden)

Piotr Karwasiński

2015-12-01

Full Text Available W artykule omówiono zagadnienia związane z procesami informatyzacji Biblioteki Uniwersyteckiej w Poznaniu. W celu dokładnego scharakteryzowania przemian, prócz rysu historycznego, przedstawiono obszary, które wyraźnie poprawiły jakość pracy personelu i obsługę czytelników oraz przyczyniły się do poznania, upowszechniania i wdrażania nowoczesnych rozwiązań technologicznych. Zaprezentowano proces zmian w zakresie funkcjonowania systemu biblioteczno-informacyjnego Horizon i współpracy z narodowym katalogiem centralnym NUKAT. Opisano etapy rozwoju elektronicznej przestrzeni informacyjnej, w tym budowania elektronicznych zasobów wiedzy i tworzenia narzędzi do ich obsługi i wykorzystania w procesach wyszukiwania źródeł informacji. Zaprezentowano Bibliotekę Uniwersytecką jako partnera w aranżowaniu instytucjonalnych platform cyfrowych do deponowania i udostępniania dorobku intelektualnego społeczności naukowej Uniwersytetu im. Adama Mickiewicza w Poznaniu. Wskazano także funkcjonalność zaprojektowanych i wdrożonych innowacyjnych usług wirtualnych pakietu Libsmart, optymalizujących funkcjonowanie Biblioteki Uniwersyteckiej.

A novel preconcentration technique for the PIXE analysis of water

International Nuclear Information System (INIS)

Savage, J.M.; Robertson, J.D.; Majidi, V.

1994-01-01

The potential of using dried algae as a novel preconcentration technique for the analysis of water samples by PIXE was examined. 5 mg of dried algae powder were mixed with 5 mL of single- and multi-metal solutions. The algae cells were then collected by filtration on 0.6 um polycarbonate membranes and analyzed by PIXE using a dual energy irradiation. When C. vulgatis was used on mixed metal solutions, linear responses were observed for Ag + , Ba 2+ , and Cd 2+ in the concentration range from 10 ng/g to 1 ug/g; for Cu 2+ and Pb 2+ from 10 ng/g to 5 ug/g; and for Hg 2+ from 10 ng/g to 10 ug/g. When S. bacillaris was used, linear responses were observed from 10 ng/g up to 10 ug/g for all of the metal cations investigated. The PIXE results demonstrated that metal binding at low concentrations involves replacement of sodium on the cell wall and that at high concentrations magnesium is also replaced

Optimization of sedimentation of tungsten on copper substrate for production of {sup 186g}Re via {sup 186}W(p,n) nuclear reaction: Feasibility of using high current, long irradiation

Energy Technology Data Exchange (ETDEWEB)

Kakavand, T., E-mail: Tayeb@znu.ac.ir [Department of Physics, Faculty of Science, Imam Khomeini International University, Qazvin (Iran, Islamic Republic of); Mirzaii, M.; Khaleghi, M. [Agricultural, Medical and Industrial Research School, Nuclear Science and Technology Research Institute, AEOI, Karaj (Iran, Islamic Republic of); Eslami, M. [Department of Physics, Faculty of Science, University of Zanjan, Zanjan (Iran, Islamic Republic of)

2016-01-01

Highlights: • Optimization of tungsten sedimentation for bulk production of {sup 186}Re. • Influence of targetry parameters on stress-bearing of the target during proton irradiation. • Activity measurement for {sup 186}Re produced via {sup nat}W(p,xn) reaction. - Abstract: Tungsten is recognized as one of the important metals used in cyclotron targets for production of several vital radioisotopes. Adequate adhesion of the prepared targets to its substrate is a significant parameter that makes them optimized for high current beam collisions. The target morphology should be paid special attention as another important parameter. In this work, a rather thick layer of tungsten is deposited on a copper substrate by sedimentation technique to produce {sup 186g}Re radionuclide via {sup 186}W(p,n) reaction. Consecutive sedimentation experiments are carried out to determine the best suspension solution. The prepared targets are evaluated in morphology by scanning electron microscope. A mixture of 1 g tungsten powder, 250 mg ethyl cellulose and 5 mL acetone is concluded for desirable target adhesion. Irradiation of the targets by 20 μA proton current (15 MeV energy) for 5 h shows that they can withstand the proton beam.

Near-bed observations of high-concentration sediment transport in the Changjiang Estuary

Science.gov (United States)

Zhou, Z.; Ge, J.; Ding, P.

2017-12-01

The North Passage, the core of turbidity maximum in the Changjiang Estuary, is now under the strong sedimentation due to the abundant sediment supply from the upstream Changjiang River and the river-tide interacted dynamics. Recent studies suggested that strong siltation could be attributed to bottom high-concentration sediment transport, which however is very difficult to be detected and observed by vessel-anchored survey methods. To better understand the mechanisms of sediment transport and deposition in the channel region of the North Passage and its adjacent areas, we conducted continuous field observations which covered spring and neap tide period in the wintertime of 2016, the summertime of 2015 and 2017, focusing on near-bottom sediment transport. Tripods mounted with multiple instruments, including up-looking and down-looking Acoustic Doppler Current Profilers(ADCP), Vector Current Meter(ADV), Optical Backscatter Sensor(OBS), ASM, ALEC and RBR were used to observe the near-bottom physical process and its induced sediment dynamics. Results of these observations clearly described the current-wave-sediment interaction, which produced different patterns of bottom mud suspension at different tripods. Both hydrodynamic features and suspended sediment showed variations between spring and neap tide. Taking data of 2016 as an example, averaged suspended sediment concentration(SSC) at two tripods was 1.52 g/L and 2.13 g/L during the neap tide, 4.51 g/L and 5.75 g/L with the peak value reaching 25 g/L during the spring tide. At the tripod which was closer to the channel region, three peaks of SSC during the spring tide occurred near the flood slack with notable salinity increase, indicating the impact of saltwater intrusion on the bottom hydrodynamics. The results showed the occurrence of high-concentration suspended sediment was probably related to combined effects of bottom salinity intrusion, turbulent kinetic energy(TKE) and local stratification due to density

Procedure for plutonium analysis of large (100g) soil and sediment samples

International Nuclear Information System (INIS)

Meadows, J.W.T.; Schweiger, J.S.; Mendoza, B.; Stone, R.

1975-01-01

A method for the complete dissolution of large soil or sediment samples is described. This method is in routine usage at Lawrence Livermore Laboratory for the analysis of fall-out levels of Pu in soils and sediments. Intercomparison with partial dissolution (leach) techniques shows the complete dissolution method to be superior for the determination of plutonium in a wide variety of environmental samples. (author)

Effect of ship locking on sediment oxygen uptake in impounded rivers

DEFF Research Database (Denmark)

Lorke, A.; McGinnis, D. F.; Maeck, A.

2012-01-01

In the majority of large river systems, flow is regulated and/or otherwise affected by operational and management activities, such as ship locking. The effect of lock operation on sediment-water oxygen fluxes was studied within a 12.9 km long impoundment at the Saar River (Germany) using eddy....... Additional means by which the oxygen budget of the impoundment is affected by lock-induced flow variations are discussed. Citation: Lorke, A., D. F. McGinnis, A. Maeck, and H. Fischer (2012), Effect of ship locking on sediment oxygen uptake in impounded rivers, Water Resour. Res., 48, W12514, doi: 10....... These wave-induced flow variations cause variations in sediment-water oxygen fluxes. While the mean flux during time periods without lock operation was 0.5 +/- 0.1 g m(-2) d(-1), it increased by about a factor of 2 to 1.0 +/- 0.5 g m(-2) d(-1) within time periods with ship locking. Following the daily...

Phylogenetically distinct bacteria involve extensive dechlorination of aroclor 1260 in sediment-free cultures.

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Shanquan Wang

Full Text Available Microbial reductive dechlorination of the persistent polychlorinated biphenyls (PCBs is attracting much attention in cleanup of the contaminated environment. Nevertheless, most PCB dechlorinating cultures require presence of sediment or sediment substitutes to maintain their dechlorination activities which hinders subsequent bacterial enrichment and isolation processes. The information on enriching sediment-free PCB dechlorinating cultures is still limited. In this study, 18 microcosms established with soils and sediments were screened for their dechlorination activities on a PCB mixture - Aroclor 1260. After one year of incubation, 10 out of 18 microcosms showed significant PCB dechlorination with distinct dechlorination patterns (e.g., Process H, N and T classified based on profiles of PCB congeners loss and new congeners formation. Through serial transfers in defined medium, six sediment-free PCB dechlorinating cultures (i.e., CW-4, CG-1, CG-3, CG-4, CG-5 and SG-1 were obtained without amending any sediment or sediment-substitutes. PCB dechlorination Process H was the most frequently observed dechlorination pattern, which was found in four sediment-free cultures (CW-4, CG-3, CG-4 and SG-1. Sediment-free culture CG-5 showed the most extensive PCB dechlorination among the six cultures, which was mediated by Process N, resulting in the accumulation of penta- (e.g., 236-24-CB and tetra-chlorobiphenyls (tetra-CBs (e.g., 24-24-CB, 24-25-CB, 24-26-CB and 25-26-CB via dechlorinating 30.44% hepta-CBs and 59.12% hexa-CBs after three months of incubation. For culture CG-1, dechlorinators mainly attacked double flanked meta-chlorines and partially ortho-chlorines, which might represent a novel dechlorination pattern. Phylogenetic analysis showed distinct affiliation of PCB dechlorinators in the microcosms, including Dehalogenimonas and Dehalococcoides species. This study broadens our knowledge in microbial reductive dechlorination of PCBs, and provides

Concentration of arsenic in water, sediments and fish species from naturally contaminated rivers.

Science.gov (United States)

Rosso, Juan José; Schenone, Nahuel F; Pérez Carrera, Alejo; Fernández Cirelli, Alicia

2013-04-01

Arsenic (As) may occur in surface freshwater ecosystems as a consequence of both natural contamination and anthropogenic activities. In this paper, As concentrations in muscle samples of 10 fish species, sediments and surface water from three naturally contaminated rivers in a central region of Argentina are reported. The study area is one of the largest regions in the world with high As concentrations in groundwater. However, information of As in freshwater ecosystems and associated biota is scarce. An extensive spatial variability of As concentrations in water and sediments of sampled ecosystems was observed. Geochemical indices indicated that sediments ranged from mostly unpolluted to strongly polluted. The concentration of As in sediments averaged 6.58 μg/g ranging from 0.23 to 59.53 μg/g. Arsenic in sediments barely followed (r = 0.361; p = 0.118) the level of contamination of water. All rivers showed high concentrations of As in surface waters, ranging from 55 to 195 μg/L. The average concentration of As in fish was 1.76 μg/g. The level of contamination with As differed significantly between species. Moreover, the level of bioaccumulation of As in fish species related to the concentration of As in water and sediments also differed between species. Whilst some fish species seemed to be able to regulate the uptake of this metalloid, the concentration of As in the large catfish Rhamdia quelen mostly followed the concentration of As in abiotic compartments. The erratic pattern of As concentrations in fish and sediments regardless of the invariable high levels in surface waters suggests the existence of complex biogeochemical processes behind the distribution patterns of As in these naturally contaminated ecosystems.

Hydroxyatrazine in soils and sediments

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Lerch, R.N.; Thurman, E.M.; Blanchard, P.E.

1999-01-01

Hydroxyatrazine (HA) is the major metabolite of atrazine in most surface soils. Knowledge of HA sorption to soils, and its pattern of stream water contamination suggest that it is persistent in the environment. Soils with different atrazine use histories were collected from four sites, and sediments were collected from an agricultural watershed. Samples were exhaustively extracted with a mixed-mode extractant, and HA was quantitated using high performance liquid chromatography with UV detection. Atrazine, deethylatrazine (DEA), and deisopropylatrazine (DIA) were also measured in all samples. Concentrations of HA were considerably greater than concentrations of atrazine, DEA, and DIA in all soils and sediments studied. Soil concentrations of HA ranged from 14 to 640 ??g/kg with a median concentration of 84 ??g/kg. Sediment concentrations of HA ranged from 11 to 96 ??g/kg, with a median concentration of 14 ??g/kg. Correlations of HA and atrazine concentrations to soil properties indicated that HA levels in soils were controlled by sorption of atrazine. Because atrazine hydrolysis is known to be enhanced by sorption and pH extremes, soils with high organic matter (OM) and clay content and low pH will result in greater atrazine sorption and subsequent hydrolysis. Significant correlation of HA concentrations to OM, pH, and cation exchange capacity of sediments indicated that mixed-mode sorption (i.e., binding by cation exchange and hydrophobic interactions) was the mechanism controlling HA levels in sediment. The presence of HA in soils and stream sediments at the levels observed support existing hypotheses regarding its transport in surface runoff. These results also indicated that persistence of HA in terrestrial and aquatic ecosystems is an additional risk factor associated with atrazine usage.

Mercury contamination history of an estuarine floodplain reconstructed from a 210Pb-dated sediment core (Berg River, South Africa)

CSIR Research Space (South Africa)

Kading, TJ

2009-01-01

Full Text Available in this 210Pb-dated sediment core at <50 ng g_1 HgT throughout the core, but with 1.3 ng g_1 methylmercury in surface sediments. The 210Pb dating of the core provides a first record of mercury deposition to the site and reveals the onset of enhanced mercury...

Intercomparison of natural radionuclide measurements in marine sediment sample SD-N-1/2

International Nuclear Information System (INIS)

1985-06-01

This intercomparison exercise was organized with the aim of providing to the participating laboratories a possibility of testing the performance of their analytical methods and to acquire basic data for establishing reference values for a number of natural radionuclides in the sediment material SD-N-1/2 from the North Sea floor. In tables are presented results expressed in mBq.g -1 on potassium, uranium isotopes, thorium-232 with the respective decay products, thorium-230, radium-226 and lead-210. Altogether 98 laboratories from 42 Member States joined this intercomparison. The results show generally good agreement, but more analytical work is needed to improve the present status of the lead-210 certification. Gamma and alpha spectroscopy were the most frequently used as the analytical techniques

Potential denitrification and nitrous oxide production in the sediments of the Seine River Drainage Network (France).

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Garnier, Josette A; Mounier, Emmanuelle M; Laverman, Anniet M; Billen, Gilles F

2010-01-01

To investigate bottom sediment denitrification at the scale of the Seine drainage network, a semi-potential denitrification assay was used in which river sediments (and riparian soils) were incubated for a few hours under anaerobic conditions with non limiting nitrate concentrations. This method allowed the nitrous oxide (N(2)O) concentration in the headspace, as well as the nitrate, nitrite, and ammonium concentrations to be determined during incubation. The rates at which nitrate decreased and N(2)O increased were then used to assess the potential denitrification activity and associated N(2)O production in the Seine River Basin. We observed a longitudinal pattern characterized by a significant increase of the potential rate of denitrification from upstream sectors to large downstream rivers (orders 7-8), from approximately 3.3 to 9.1 microg NO(3)(-)-N g(-1) h(-1), respectively, while the N(2)O production rates was the highest both in headwaters and in large order rivers (0.14 and 0.09 N(2)O-N g(-1) h(-1), respectively) and significantly lower in the intermediate sectors (0.01 and 0.03 N(2)O-N g(-1) h(-1)). Consequently, the ratio N(2)O production:NO(3) reduction was found to reach 5% in headstreams, whereas it averaged 1.2% in the rest of the drainage network, an intermediate percentage being found for the riparian soils. Finally, the ignition loss of sediments, together with other redundant variables (particulate organic carbon content: g C 100 g(-1) dry weight [dw], moisture: g water 100 g(-1) dw, sediment size production.

Surface-sediment and hermit-crab contamination by butyltins in southeastern Atlantic estuaries after ban of TBT-based antifouling paints.

Science.gov (United States)

Sant'Anna, B S; Santos, D M; Marchi, M R R; Zara, F J; Turra, A

2014-05-01

Butyltin (BT) contamination was evaluated in hermit crabs from 25 estuaries and in sediments from 13 of these estuaries along about 2,000 km of the Brazilian coast. BT contamination in hermit crabs ranged from 2.22 to 1,746 ng Sn g(-1) of DBT and 1.32 to 318 ng Sn g(-1) of TBT. In sediment samples, the concentration also varied widely, from 25 to 1,304 ng Sn g(-1) of MBT, from 7 to 158 ng Sn g(-1) of DBT, and from 8 to 565 ng Sn g(-1) of TBT. BTs are still being found in surface sediments and biota of the estuaries after the international and Brazilian bans, showing heterogeneous distribution among and within estuaries. Although hermit crabs were previously tested as an indicator of recent BT contamination, the results indicate the presence of contamination, probably from resuspension of BTs from deeper water of the estuary.

Bacteriological study of the superficial sediments of Guanabara bay, RJ, Brazil

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Frederico Sobrinho da Silva

2008-03-01

Full Text Available Thirty sediment samples were collected in Guanabara Bay in August, November and December 2005. The material was analyzed for organic matter, total and faecal coliforms, heterotrophic bacteria, bacterial respiratory activity, esterase activity and electron transport system activity. The organic matter in the superficial sediments (2 cm ranged from 4 to 6%. The highest level of total coliforms and faecal coliforms were 1.7 x 10(5 MPN/g and 1.1 x 10³ MPN/g, respectively. Heterotrophic bacteria presented the highest values at station 7 (4.1 x 10(6 CFU/g and the lowest values at station 3 (7 x 10(4 CFU/g (northwestern part of Guanabara Bay. Esterase enzyme activity showed activity in the sediment of all 30 stations. Electron transport system activity ranged between 0.047 muL O2/h/g and 0.366 muL O2/h/g at six stations. The benthic microbial foodweb is anaerobic. Anaerobic processes such as fermentation, denitrification and sulphate-reduction are responsible for the biogeochemical cycles in the sediment of Guanabara Bay. The input of untreated sewage in the Mangue Channel outflow in Guanabara Bay has favored the increase of the organic load, and the maintenance of the total coliforms and faecal coliforms in the sediment. Faecal coliforms have been reported to be a good indicator of aquatic pollution and organic contamination in the water column, but total coliforms may be an ideal candidate group for sediment quality tests as well.Trinta amostras de sedimento foram coletadas na Baía de Guanabara em agosto, novembro e dezembro de 2005. Foram analisados matéria orgânica, coliformes totais e fecais, bactéria heterotrófica, atividade respiratória bacteriana, atividade de esterase e do sistema transportador de elétrons. A matéria orgânica no sedimento superficial variou entre 4 e 6%. O maior nível de coliformes totais e fecais foi 1.7 x 10(5 MPN/g e 1.1 x 10³ MPN/g, respectivamente. Bactérias heterótrofas mostraram o maior valor na esta

Butyltins and phenyltins in biota and sediments from the Lagoon of Venice

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Angelo Bortoli

2003-03-01

Full Text Available Sediments and organisms were sampled to determine organotin contents - butyltins (BTs and phenyltins (PhTs - at 12 locations in an estuarine ecosystem, the Lagoon of Venice, characterised by varying contamination impacts. The results showed that organotin contamination in sediments is at lower levels, ranging from 2.5 ± 0.1 to 84 ± 1 ng g-1 (d.w. for SigmaBTs and from 0.8 ± 0.2 to 7 ± 1 ng g-1 (d.w., for SigmaPHTs, than in organisms, where the highest concentrations were found infilter feeders like mussels - from 60 ± 3 to 7632 ± 148 ng g-1 (d.w. for SigmaBTs and from 0.80 ± 0.01 to 4005 ± 121 ng g-1 (d.w. for SigmaPHTs. The possible risk to human health was assessed on the basis of the consumption of edible species sampled in some areas of the lagoon.

OIL DECONTAMINATION OF BOTTOM SEDIMENTS EXPERIMENTAL WORK RESULTS

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Lushnikov Sergey V.

2006-08-01

Full Text Available This article presents the results of experimental work during 2004-2005 on oil decontamination of bottom sediments of Lake Schuchye, situated in the Komi Republic (Northern Russia. The cause of thecontamination were huge oil spills occurred after a series of accidental ruptures on the Harjaga-Usinsk and Vozej-Usinsk oil-pipe lines in 1994. Flotation technology was used for the cleaning of bottom sediments.157 tons of crude oil were removed during the course of 2-year experimental work from an area of 4,1 ha.The content of aliphatic and alicyclic oil hydrocarbons was reduced from 53,3 g/kg to 2,2 g/kg, on average.Hydrobiological investigations revealed that bottom sediments started to be inhabited by benthos organisms, dominantly Oligochaeta. Besides Oligochaeta, Chironomidae maggots and Bivalvia were detected. Theappearance of Macrozoobenthos organisms can serve as a bioindicator of water quality.

The I.A.G. / A.I.G. SEDIBUD (Sediment Budgets in Cold Environments) Programme: Current and future activities

Science.gov (United States)

Beylich, Achim A.; Lamoureux, Scott; Decaulne, Armelle

2013-04-01

Projected climate change in cold regions is expected to alter melt season duration and intensity, along with the number of extreme rainfall events, total annual precipitation and the balance between snowfall and rainfall. Similarly, changes to the thermal balance are expected to reduce the extent of permafrost and seasonal ground frost and increase active layer depths. These effects will undoubtedly change surface environments in cold regions and alter the fluxes of sediments, nutrients and solutes, but the absence of quantitative data and coordinated geomorphic process monitoring and analysis to understand the sensitivity of the Earth surface environment is acute in cold climate environments. The International Association of Geomorphologists (I.A.G. / A.I.G. ) SEDIBUD (Sediment Budgets in Cold Environments) Programme was formed in 2005 to address this existing key knowledge gap. SEDIBUD currently has about 400 members worldwide and the Steering Committee of this international programme is composed of ten scientists from eight different countries: Achim A. Beylich (Chair) (Norway), Armelle Decaulne (Secretary) (France), John C. Dixon (USA), Scott F. Lamoureux (Vice-Chair) (Canada), John F. Orwin (Canada), Jan-Christoph Otto (Austria), Irina Overeem (USA), Thorsteinn Sæmundsson (Iceland), Jeff Warburton (UK) and Zbigniew Zwolinski (Poland). The central research question of this global group of scientists is to: Assess and model the contemporary sedimentary fluxes in cold climates, with emphasis on both particulate and dissolved components. Initially formed as European Science Foundation (ESF) Network SEDIFLUX (Sedimentary Source-to-Sink Fluxes in Cold Environments) (2004 - ), SEDIBUD has further expanded to a global group of researchers with field research sites located in polar and alpine regions in the northern and southern hemisphere. Research carried out at each of the close to 50 defined SEDIBUD key test sites varies by programme, logistics and available

The distribution of plutonium, americium and curium isotopes in pond and stream sediments of the Savannah River Plant, South Carolina, USA

International Nuclear Information System (INIS)

Alberts, J.J.; Halverson, J.E.; Orlandini, K.A.

1986-01-01

The concentrations of 238 Pu, 239 , 240 Pu, 241 Am and 244 Cm were determined in sediment samples from five streams and two ponds on the Savannah River Plant (SRP) and in four sediment samples from the Savannah River above and below the plant site. The following concentration ranges were determined: 238 Pu, 0.07-386 fCi g -1 ; 239 , 240 Pu, 0.37-1410 fCi g -1 ; 241 Am, 0.1-4360 fCi g -1 ; 244 Cm, -1 . Comparisons of the elemental and isotopic ratios of the sediments show that the majority of the sediments studied have been impacted upon by plant operations and that sediments outside the plant boundary in the Savannah River have only been influenced by aerial releases. Atom ratios of 240 Pu/ 239 Pu indicate that up to 86% of the Pu in these sediments is derived from plant operations. However, comparisons of the concentration data with values for other impacted sediments near nuclear facilities indicate that the levels are relatively small. Finally, <13% of the Pu, Am or Cm in pond sediments is associated with humic or fulvic acids, indicating that little of the material should be remobilized in oxic environments through organic complexation. (author)

Biosorption of U(VI) by the green algae Chlorella vulgaris in dependence of pH value and cell activity

Energy Technology Data Exchange (ETDEWEB)

Vogel, M., E-mail: M.Vogel@fzd.de; Guenther, A.; Rossberg, A.; Li, B.; Bernhard, G.; Raff, J.

2010-12-15

Biosorption of uranium(VI) by the green alga Chlorella vulgaris was studied at varying uranium concentrations from 5 {mu}M to 1 mM, and in the environmentally relevant pH range of 4.4 to 7.0. Living cells bind in a 0.1 mM uranium solution at pH 4.4 within 5 min 14.3 {+-} 5.5 mg U/g dry biomass and dead cells 28.3 {+-} 0.6 mg U/g dry biomass which corresponds to 45% and 90% of total uranium in solution, respectively. During 96 h of incubation with uranium initially living cells died off and with 26.6 {+-} 2.1 mg U/g dry biomass bound similar amounts of uranium compared to dead cells, binding 27.0 {+-} 0.7 mg U/g dry biomass. In both cases, these amounts correspond to around 85% of the initially applied uranium. Interestingly, at a lower and more environmentally relevant uranium concentration of 5 {mu}M, living cells firstly bind with 1.3 {+-} 0.2 mg U/g dry biomass to 1.4 {+-} 0.1 mg U/g dry biomass almost all uranium within the first 5 min of incubation. But then algal cells again mobilize up to 80% of the bound uranium during ongoing incubation in the time from 48 h to 96 h. The release of metabolism related substances is suggested to cause this mobilization of uranium. As potential leachates for algal-bound uranium oxalate, citrate and ATP were tested and found to be able to mobilize more than 50% of the algal-bound uranium within 24 h. Differences in complexation of uranium by active and inactive algae cells were investigated with a combination of time-resolved laser-induced fluorescence spectroscopy (TRLFS), extended X-ray absorption fine structure (EXAFS) spectroscopy and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Obtained results demonstrated an involvement of carboxylic and organic/inorganic phosphate groups in the uranium complexation with varying contributions dependent on cell status, uranium concentration and pH.

Biosorption of U(VI) by the green algae Chlorella vulgaris in dependence of pH value and cell activity

International Nuclear Information System (INIS)

Vogel, M.; Guenther, A.; Rossberg, A.; Li, B.; Bernhard, G.; Raff, J.

2010-01-01

Biosorption of uranium(VI) by the green alga Chlorella vulgaris was studied at varying uranium concentrations from 5 μM to 1 mM, and in the environmentally relevant pH range of 4.4 to 7.0. Living cells bind in a 0.1 mM uranium solution at pH 4.4 within 5 min 14.3 ± 5.5 mg U/g dry biomass and dead cells 28.3 ± 0.6 mg U/g dry biomass which corresponds to 45% and 90% of total uranium in solution, respectively. During 96 h of incubation with uranium initially living cells died off and with 26.6 ± 2.1 mg U/g dry biomass bound similar amounts of uranium compared to dead cells, binding 27.0 ± 0.7 mg U/g dry biomass. In both cases, these amounts correspond to around 85% of the initially applied uranium. Interestingly, at a lower and more environmentally relevant uranium concentration of 5 μM, living cells firstly bind with 1.3 ± 0.2 mg U/g dry biomass to 1.4 ± 0.1 mg U/g dry biomass almost all uranium within the first 5 min of incubation. But then algal cells again mobilize up to 80% of the bound uranium during ongoing incubation in the time from 48 h to 96 h. The release of metabolism related substances is suggested to cause this mobilization of uranium. As potential leachates for algal-bound uranium oxalate, citrate and ATP were tested and found to be able to mobilize more than 50% of the algal-bound uranium within 24 h. Differences in complexation of uranium by active and inactive algae cells were investigated with a combination of time-resolved laser-induced fluorescence spectroscopy (TRLFS), extended X-ray absorption fine structure (EXAFS) spectroscopy and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Obtained results demonstrated an involvement of carboxylic and organic/inorganic phosphate groups in the uranium complexation with varying contributions dependent on cell status, uranium concentration and pH.

Transport of perfluoroalkyl acids in a water-saturated sediment column investigated under near-natural conditions

International Nuclear Information System (INIS)

Vierke, Lena; Möller, Axel; Klitzke, Sondra

2014-01-01

The aim of this study was to gain an understanding of the transport of C 4–10 perfluoroalkyl carboxylic acids (PFCAs) and C 4,6,8 perfluoroalkyl sulfonic acids (PFSAs) in a water-saturated sediment column representing a riverbank filtration scenario under near-natural conditions. Short-chain PFCAs and PFSAs with up to six C-atoms showed complete tracer-like breakthrough. Longer chain ones were retarded due to sorption to the sediment or due to other processes in the aqueous phase. The study reports the first column derived sediment–water partition coefficients ranging from 0.01 cm 3 g −1 to 0.41 cm 3 g −1 for C 4,6 PFSAs and from 0.0 cm 3 g −1 to 6.5 cm 3 g −1 for C 4,5,6,8,9 PFCAs. The results clearly indicate that short-chain PFCAs and PFSAs may pose a problem if contaminated surface waters are used for drinking water production via riverbank filtration. Highlights: • Transport of per- and polyfluorinated compounds in a riverbank filtration scenario. • Investigations under near-natural conditions with a water-saturated sediment column. • Processes in water and sediment control the transport of analytes. • Short chain PFCAs and PFSAs are not retarded in the water-saturated sediment column. • First column derived sediment–water partition coefficients. -- Quantification of breakthrough of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) under conditions simulating a riverbank filtration scenario

Effects of Cuban Crude Oil on the Process of Leach, Sedimentation and Distillation in Nicaro

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Ing. María Elena Magaña-Haynes

2015-11-01

Full Text Available ine"> sedimentation and distillation ofthe processed minerals at “René Ramos Latour” Company was evaluated. Two periods of testswere performed; one when oil was introduced into the furnace by spear and the other when itwas introduced by spear and chamber. The results demonstrated the feasibility of using theCuban crude in reduction and leaching process of mineral by the use of spear and chamber aswell. Nickel and cobalt extractions achieved by stepwise exceed values found in the relatedliterature. Deposition of mineral was good reaching values of 1,736 -1,745 kg/m3 at the bottomof the sedimentation stage leach and 1,774 -1,807 kg/m3 in the washing stage. The thickenerswere maintained with high clear liquor level throughout the test with values between 28,0-30,0ppm. The sedimentation rate achieved low values both in the first and in the second leachingstage. Sedimentation unit area was 0,23 m2 /T day, so that no sedimentation problems werepresented. It was observed an increase in the sulfur content up to values of 6,52 g/L for a nickelcontent of 12,0g/L, which caused that the dissolved nickel in downloading stills were of 0,392 g/L and 2,58 g/L of ammonia. The sulfur content in the nickel carbonate was increased upto 6,30 %, which is 2,5 % higher than conventional.

Contamination of nonylphenolic compounds in creek water, wastewater treatment plant effluents, and sediments from Lake Shihwa and vicinity, Korea: Comparison with fecal pollution

Science.gov (United States)

Choi, Minkyu; Furlong, Edward T.; Moon, Hyo-Bang; Yu, Jun; Choi, Hee-Gu

2011-01-01

Nonylphenolic compounds (NPs), coprostanol (COP), and cholestanol, major contaminants in industrial and domestic wastewaters, were analyzed in creek water, wastewater treatment plant (WWTP) effluent, and sediment samples from artificial Lake Shihwa and its vicinity, one of the most industrialized regions in Korea. We also determined mass discharge of NPs and COP, a fecal sterol, into the lake, to understand the linkage between discharge and sediment contamination. Total NP (the sum of nonylphenol, and nonylphenol mono- and di-ethoxylates) were 0.32–875 μg L-1 in creeks, 0.61–87.0 μg L-1 in WWTP effluents, and 29.3–230 μg g-1 TOC in sediments. Concentrations of COP were 0.09–19.0 μg L-1 in creeks, 0.11–44.0 μg L-1 in WWTP effluents, and 2.51–438 μg g-1 TOC in sediments. The spatial distributions of NPs in creeks and sediments from the inshore region were different from those of COP, suggesting that Lake Shihwa contamination patterns from industrial effluents differ from those from domestic effluents. The mass discharge from the combined outfall of the WWTPs, located in the offshore region, was 2.27 kg d-1 for NPs and 1.00 kg d-1 for COP, accounting for 91% and 95% of the total discharge into Lake Shihwa, respectively. The highest concentrations of NPs and COP in sediments were found in samples at sites near the submarine outfall of the WWTPs, indicating that the submarine outfall is an important point source of wastewater pollution in Lake Shihwa.

Mercury in litterfall and sediment using elemental and isotopic composition of carbon and nitrogen in the mangrove of Southeastern Brazil

Science.gov (United States)

Fragoso, Cynara Pedrosa; Bernini, Elaine; Araújo, Beatriz Ferreira; Almeida, Marcelo Gomes de; Rezende, Carlos Eduardo de

2018-03-01

Mercury and elemental and isotopic compositions of carbon and nitrogen were determined in litterfall and sediments from the mangrove of the Paraíba do Sul River, Rio de Janeiro, Brazil. Total mercury (THg) and monomethylmercury (MMHg) concentrations in sediment ranged from 33 to 123 ng g-1 and 0.20-1.38 ng g-1, respectively. The δ13C in sediment varied from -29.4 to -26.5‰ and from 2.4 to 5.8‰ in δ15N. The THg concentration in litterfall and its annual input to the mangrove was 21 ± 2 ng g-1 and 16 ± 4 μg m-2 for the species Laguncularia racemosa, 18 ± 1 ng g-1 and 17 ± 3 μg m-2 for Rhizophora mangle, and 53 ± 4 ng g-1 and 33 ± 4 μg m-2 for Avicennia germinans, respectively. The isotopic composition of leaf litter ranged from -28.6 to -26.9‰ for δ13C and 4.5-7.2‰ for δ15N. Both the highest annual Hg input via litterfall and highest sediment Hg concentration were observed in areas dominated by A. germinans. These results suggest that the rate of litterfall of plant species and the atmospheric deposition have played an important role in the Hg biogeochemical cycle in the mangrove ecosystem.

Spatial distribution of heavy metals in sediments from the Gulf of Paria,Trinidad

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Wendy Norville

2005-05-01

Full Text Available The Gulf of Paria receives heavy metal input from urban runoff,industrial and agricultural activity, sewage and domestic wastes:both from the west coast and from inland areas of Trinidad.Non-residual concentrations of nine metals,as well as total mercury concentrations,were used to determine spatial distributions of heavy metals in sediments in the Gulf of Paria.Surficial sediment samples were collected at 37 stations,which included the mouths of 11 major rivers that flow into the Gulf of Paria.Stations were sampled twice during the wet season (July 1998 and November/December 1998and twice during the dry season (March 1999 and April 1999.Sediments were analyzed for aluminium (Al,cadmium (Cd,chromium (Cr,copper (Cu,iron (Fe, lead (Pb,manganese (Mn,nickel (Ni,zinc (Znand mercury (Hg.Total Organic Carbon (TOCand grain size analyses were also performed on the sediments.Principal component analysis showed that sediments from river mouths subject to greatest land use and anthropogenic input,were distinct from other sediments in the Gulf of Paria.This was due to higher Pb,Zn,Cu and Hg concentrations (3.53-73.30 µg g-1 ,45.8-313.9 µg g-1 ,8.43-39.71 µg g-1 and 0.03-0.10 µg g-1 ,respectively.Sediments further from the coast were also distinct due to their higher Al,Fe,Cr and Mn concentrations (1.37-3.16 mg g-1 ,9.51-18.91 mg g-1 ,17.22-28.41 µg g-1 and 323.6 -1,564.2 µg g-1 ,respectively.Cd and Pb were higher in the wet season while Ni was higher in the dry season.Pb,Zn,Cu and Hg were correlated with each other and with TOC.Correlation was also observed between Al,Fe,Cr,Mn and Ni.Al,Fe,Cr and Mn were correlated with percentage clay in sediments.The results suggest that Pb,Zn, Cu and Hg are preferentially removed by organic matter,which settles at the river-mouths,while Al,Fe,Cr,Mn, and Ni become associated with clay minerals and are transported away from the coast.El Golfo de Paria recibe metales pesados de zonas urbanas,industriales y agr

Temporal shifts in reef lagoon sediment composition, Discovery Bay, Jamaica

Science.gov (United States)

Perry, Christopher T.; Taylor, Kevin G.; Machent, Philip G.

2006-03-01

Discovery Bay, north Jamaica, forms a large (1.5 km wide), deep (up to 56 m) embayment that acts as a sink for reef-derived and lagoonal carbonate sediments. Since the mid-1960s, the bay has also provided a sink for inputs of bauxite sediment that are spilled during loading at a boat terminal constructed within Discovery Bay. Bauxite has accumulated across much of the southern section of the bay with surficial sediments presently composed of up to 35 weight% non-carbonate. Cores recovered from sites on the western side of the bay provide a stratigraphic record of this history of bauxite contamination across water depths from 5 to 25 m. The bauxite-influenced upper sediment horizons are clearly visible in each core from the distinctive red-brown colouration of the sediment. These sediments are composed of approximately 10% non-carbonate (bauxite) and have Fe contents of around 2-3000 μg/g (up to 7000 μg/g). The thickness of this upper bauxite-contaminated sequence increases down transect (approximately 18 cm in the shallowest core, to around 47 cm in the deepest core), and in each core overlies a sequence of 'clean' lagoon carbonates. These typically are poorly sorted carbonate sands with variable amounts of coral rubble. Down-core data on CaCO 3 and Fe content provide a chemical record of decreasing sediment contamination with depth, with the lower 'clean' carbonates composed of only around 2% non-carbonate and coral, mollusc, Amphiroa and Halimeda in the clean lagoon sands, to assemblages dominated by Halimeda and Amphiroa within the surficial sediments. At the deeper sites, no major down-core shifts in sediment constituents occur. These sites thus record a rather complex history of changes in sediment composition and chemistry. Clear shifts in chemistry and stratigraphy occur in all the cores and reflect progressive bauxite contamination in the near-surface horizons. These inputs, however, do not appear to have directly affected carbonate production, since the

Contamination assessment of heavy metal in surface sediments of the Wuding River, northern China

International Nuclear Information System (INIS)

Longjiang, M.; Qiang, F.; Duowen, M.; Ke, H.; Jinghong, Y.

2011-01-01

The heavy metal contents and the contamination levels of the surface sediments of the Wuding River, northern China, were investigated. Heavy metal concentration ranged in μg g -1 : 50.15 - 71.91 for Cr, 408.1 - 442.9 for Mn, 20.11 - 43.59 for Ni, 17.51 - 20.1 for Cu, 68.32 - 89.57 for Zn, 0.2 - 0.38 for Cd and 15.08 - 16.14 for Pb in the Wuding River sediments. The enrichment factor (EF) and the geo-accumulation index (Igeo) demonstrated that the sediments of the Wuding River had been polluted by Cd, Cr and Ni, which mainly originated from anthropogenic sources, whereas the sediments had not been polluted by Zn, Pb, Cu and Mn, which were derived from the crust. In addition, the assessment results of EF and Igeo suggested that the sediments of the Wuding River was 'moderately' polluted by Cd and 'unpolluted to moderately' polluted by Cr and Ni. The elevated urban sewage discharges and agriculture fertilizers usage in river basin are the anthropogenic sources of these heavy metals in river. (author)

Sediment nickel bioavailability and toxicity to estuarine crustaceans of contrasting bioturbative behaviors--an evaluation of the SEM-AVS paradigm.

Science.gov (United States)

Chandler, G Thomas; Schlekat, Christian E; Garman, Emily R; He, Lijian; Washburn, Katherine M; Stewart, Emily R; Ferry, John L

2014-11-04

Robust sediment quality criteria require chemistry and toxicity data predictive of concentrations where population/community response should occur under known geochemical conditions. Understanding kinetic and geochemical effects on toxicant bioavailability is key, and these are influenced by infaunal sediment bioturbation. This study used fine-scale sediment and porewater measurement of contrasting infaunal effects on carbon-normalized SEM-AVS to evaluate safe or potentially toxic nickel concentrations in a high-binding Spartina saltmarsh sediment (4%TOC; 35-45 μmol-S2-·g(-1)). Two crustaceans producing sharply contrasting bioturbation--the copepod Amphiascus tenuiremis and amphipod Leptocheirus plumulosus--were cultured in oxic to anoxic sediments with SEM[Ni]-AVS, TOC, porewater [Ni], and porewater DOC measured weekly. From 180 to 750 μg-Ni·g(-1) sediment, amphipod bioturbation reduced [AVS] and enhanced porewater [Ni]. Significant amphipod uptake, mortality, and growth-depression occurred at the higher sediment [Ni] even when [SEM-AVS]/foc suggested acceptable risk. Less bioturbative copepods produced higher AVS and porewater DOC but exhibited net population growth despite porewater [Ni] 1.3-1.7× their aqueous [Ni] LOEC. Copepod aqueous tests with/without dissolved organic matter showed significant aqueous DOC protection, which suggests porewater DOC attenuates sediment Ni toxicity. The SEM[Ni]-AVS relationship was predictive of acceptable risk for copepods at the important population-growth level.

The phosphorus content of fluvial sediment in rural and industrialized river basins.

Science.gov (United States)

Owens, Philip N; Walling, Desmond E

2002-02-01

The phosphorus content of fluvial sediment (suspended sediment and the sediment) has been examined in contrasting rural (moorland and agricultural) and industrialized catchments in Yorkshire, UK. The River Swale drains a rural catchment with no major urban and industrial areas, and the total phosphorus (TP) content of fluvial sediment is generally within the range 500-1,500 microg g(-1). There is little evidence of any major downstream increase in TP content. In contrast, fluvial sediment from the industrialized catchments of the Rivers Aire and Calder exhibits both higher levels of TP content and marked downstream increases, with values of TP content ranging from 7,000 microg g(-1) at downstream sites. These elevated levels reflect P inputs from point sources, such as sewage treatment works (STWs) and combined sewer overflows. The influence of STWs is further demonstrated by the downstream increase in the inorganic P/organic P ratio from 4 in the lower reaches. Comparison of the P content of suspended sediment with that of the sediment and both discharge and suspended sediment concentration, reflecting changes in sediment and P sources during high flow events. Spatial variations in the P contents of the sediment evidence a similar pattern as those for suspended sediment, with relatively low levels of TP in the River Swale and elevated levels in the middle and downstream reaches of the Rivers Aire and Calder. The PP concentrations associated with floodplain and channel bed sediment are, however, lower than equivalent values for suspended sediment, and this primarily reflects the differences in the particle size composition between the three types of sediments. Rates of floodplain deposition and the amounts of fine-grained sediment stored in the river channels are relatively high, and suggest that such environments may represent important sinks for PP. Based on the sediment samples collected from the study basins, a simple four-fold classification which relates the

Concentration of "1"3"4Cs + "1"3"7Cs bonded to the organic fraction of sediments offshore Fukushima, Japan

International Nuclear Information System (INIS)

Ono, Tsuneo; Ambe, Daisuke; Kaeriyama, Hideki

2015-01-01

We conducted a sequential chemical extraction experiment for radiocesium ("1"3"4Cs + "1"3"7Cs) using 21 surface sediment samples and two sets of size-fractionated surface sediment samples collected offshore Fukushima. Our results support earlier reports in this area that organic substances in marine sediments have an apparently higher preference for radiocesium than mineral substances. Observations suggest that mineral and organic substances in the marine sediments offshore Fukushima have the same order of preference for radiocesium, primarily because of the existence of ionic competitors in seawater. The apparent preference of radiocesium for organic material is greater because of the partial coverage of sediment mineral surfaces by organic substances. By using these relationships, we created a 2-D map of radiocesium concentration in sediment organic fraction in offshore-Fukushima region. Combining our results with existing monitoring data of marine benthos in offshore-Fukushima sediments, we estimated a transfer coefficient of radiocesium from sediment organic materials to benthic polychaetes as less than 0.03-0.008. (author)

[Composition and Environmental Effects of LFOM and HFOM in "Incense-Ash" Sediments of West Lake, Hangzhou, China].

Science.gov (United States)

Li, Jing; Zhu, Guang-wei; Zhu, Meng-yuan; Gong, Zhi-jun; Xu, Hai; Yang, Gui-jun

2015-06-01

To understand the organic matter pollution characteristic and its relationship with nitrogen, phosphorus and other nutrients in sediments of high organic matter type of urban shallow lakes, the organic matter content, light fraction organic matter (LFOM), heavy fraction organic matter (HFOM), and nitrogen and phosphorus contents were investigated in eight different regions of West Lake, Hangzhou. The results showed that, the organic matter content of the west lake sediment was 28-251 g x kg(-1), belonging to typical high organic matter sediment. The difference of organic matter content in different lake sediments was very big. The sediments located at the input site of water diversion engineering had significantly lower organic content than the rest regions. The LFOM content of West Lake sediment ranged 0.57-9.17 g x kg(-1), which averagely occupied 2.83% of the total organic matter, and the HFOM content ranged 5.35-347.41 g x kg(-1), which occupied more than 90% of the total organic matter. Compared to other shallow lakes located in China, sediments of West Lake had significantly high percentage of HFOM/LFOM ratio. But the HFOM content was obviously on the high side, reflecting the west lake as an urban lake with a long history, as well as high organic matter pollution load and sediment humification degree. Both the content and the ratio of LFOM/HFOM in sediment were related to nitrogen and phosphorus contents in sediment. This suggested that the composition of organic matter in West Lake sediments had potential control ability for the internal loading of N and P of the lake.

Copper clean-up procedure for ultrasonic extraction and analysis of pyrethroid and phenylpyrazole pesticides in sediments by gas chromatography-electron capture detection

Energy Technology Data Exchange (ETDEWEB)

Wu Jun; Lin Youjian; Lu Jian; Wilson, Chris, E-mail: pcwilson@ufl.edu

2011-08-15

A rapid ultrasonic extraction method coupled with a heated-copper clean-up procedure for removing interfering constituents was developed for analyzing pyrethroid and phenylpyrazole pesticides in sediments. Incubation of the 60 mL extract with 12 g copper granules at 60 {sup o}C for 2 h was determined to be the optimal conditions for removing the interfering constituents. Eleven pyrethroid and phenylpyrazole pesticides were spiked into sediment samples to determine the effectiveness of the ultrasonic extraction method. The average recoveries of pyrethroids and phenylpyrazoles in sediment at 4 {sup o}C storage on day 0, 1, 7, 14, and 21 ranged from 98.6 to 120.0%, 79.2 to 116.0%, 85.0 to 119.7%, 93.6 to 118.7%, and 92.1 to 118.2%, respectively, with all percent relative standard deviations less than 10% (most < 6%). This illustrated the stability of pyrethroids and phenylpyrazoles in sediment during sediment aging at 4 {sup o}C. Recoveries of the pesticides ranged from 98.6% to 120.0% for lowest fortification level (2-16 {mu}g kg{sup -1}), from 97.8% to 117.9% for middle fortification level (10-80 {mu}g kg{sup -1}), and from 94.3% to 118.1% for highest fortification level (20-160 {mu}g kg{sup -1}). Relative standard deviations of pesticide recoveries were usually less than 7%. Method detection limits of target pesticides ranged from 0.22 {mu}g kg{sup -1} to 3.72 {mu}g kg{sup -1}. Furthermore, field sediment samples collected from four residential lakes during a three-month monitoring period were analyzed to evaluate the effectiveness of this method. Bifenthrin was detected in all of sediment samples (highest concentration 260.33 {+-} 41.71 {mu}g kg{sup -1}, lowest concentration 5.68 {+-} 0.38 {mu}g kg{sup -1}), and fipronil sulfone was detected at least once in sediment samples collected from three sites with concentrations ranging from 1.73 {+-} 0.53 to 7.53 {+-} 0.01 {mu}g kg{sup -1}. - Highlights: {yields} A rapid extraction and copper-based clean-up method was

Elucidation of 10Be accumulation mechanism to sea floor with the marine sediment

International Nuclear Information System (INIS)

Yoshida, T.; Yamagata, T.; Saito, T.; Nagai, H.; Matsuzaki, H.

2006-01-01

Marine sediment samples (0-30 cm in depth) were collected in the Northwest Pacific Ocean, and South Pacific Ocean during KH00-3 (BO, 7 samples) and KH04-5 (SX, 8 samples) cruise of R/V Hakuho-Maru. The 10 Be concentration in the marine sediment samples range between 0.9x10 9 and 6.5x10 9 atoms/g, and most of the red clay sediment in the Northwest Pacific Ocean showed uniform distribution. The 9 Be concentration in the red clay sediment samples range between 2.3 and 2.6 ppm, which showed a value almost the same as measured 9 Be concentration (1.6-2.3 ppm) in the Chinese loess. The 10 Be concentration in the marine sediment were 20 times higher than the 10 Be concentration (0.2x10 9 atoms/g) in the Chinese loess. These results were suggested that most of 10 Be in the marine sediment were regarded seawater as the origin. (author)

Synergistic effects of diuron and sedimentation on photosynthesis and survival of crustose coralline algae

International Nuclear Information System (INIS)

Harrington, Lindsay; Fabricius, Katharina; Eaglesham, Geoff; Negri, Andrew

2005-01-01

Effects of short-term exposure to sedimentation and diuron, separately and in combination, on the photophysiology and survival of crustose coralline algae (CCA) were examined in controlled time-course experiments, using pulse-amplitude modulation (PAM) chlorophyll fluorometry. These experiments indicated that the effects of sediments and diuron, when applied in isolation, were often reversible, with recovery time dependant upon sediment type and diuron concentration. Exposure to fine ( m' ) of photosystem II in CCA species more than exposure to the same amount of fine ( m' ) was also observed at diuron concentrations 2.9 μg L -1 . Fine estuarine sediments in combination with 0.79 μg L -1 dissolved diuron, caused yields (ΔF/F m' ) to drop by 60% compared with controls after 24 h. The combined exposure to sediments and diuron also retarded recovery, thus ΔF/F m' values were still only 60% of the controls after 9 days recovery in clean seawater. Mortality of CCA was observed in some fragments treated with combinations of sediment and diuron. Our results suggest that sediment deposition and exposure to diuron can negatively affect the photosynthetic activity of CCA, with sedimentation stress being significantly enhanced by the presence of trace concentrations of diuron

Distribution, Source, and Ecological Risk Assessment of Polycyclic Aromatic Hydrocarbons in Surface Sediment of Liaodong Bay, Northeast China

Science.gov (United States)

Xu, Shuang; Tao, Ping; Li, Yuxia; Guo, Qi; Zhang, Yan; Wang, Man; Jia, Hongliang; Shao, Mihua

2018-01-01

Sixteen polycyclic aromatic hydrocarbons (PAHs) were determined in surface sediments from Liaodong Bay, northeast China. The concentration levels of total PAHs (Σ16PAHs) in sediment were 11.0˜249.6 ng·g-1 dry weight (dw), with a mean value of 89.9 ng·g-1 dry weight (dw). From the point of the spatial distribution, high PAHs levels were found in the western areas of Liaodong Bay. In the paper, sources of PAHs were investigated by diagnostic ratios, which indicated that pyrogenic sources were the main sources of PAHs in the sediment of Liaodong Bay. Therefore, selected PAH levels in sediments were compared with Sediments Quality Guidelines (ERM-ERL indexes) for evaluation probable toxic effects on marine organism.

Atmospheric lead fallout over the last century recorded in Gulf of Lions sediments (Mediterranean Sea)

International Nuclear Information System (INIS)

Miralles, J. . E-mail jmiralles@wanadoo.fr; Veron, A.J.; Radakovitch, O.; Deschamps, P.; Tremblay, T.; Hamelin, B.

2006-01-01

Six marine sediment cores from the Gulf of Lions continental slope (700-1700 m water depth) were analyzed for stable lead isotopes and 21 Pb geochronology in order to reconstruct lead atmospheric fallout pattern during the last century. The detrital lead contribution is 25 μg g -1 and the mean sediment anthropogenic inventory is 110 ± 7 μg cm -2 , a little bit higher than atmospheric deposition estimate. Anthropogenic lead accumulation in sediments peaked in early 1970s (1973 ± 2) in agreement with lead emissions features. For the period 1986-1997, the sediment signal also reflect the decrease of atmospheric lead described by independent atmospheric fallout investigations. The anthropogenic Pb deposition in the late 1990s was similar to the 1950s deposition, attesting thus of the output of European environmental policies

Coupling of bacterial nitrification with denitrification and anammox supports N removal in intertidal sediments (Arcachon Bay, France)

Digital Repository Service at National Institute of Oceanography (India)

Fernandes, S.O.; Javanaud, C.; Michotey, V.D.; Guasco, S.; Anschutz, P.; Bonin, P.

> equivalent cell per g^-1 dry weight sediment and were overall more abundant in muddy sediments. Archaeal equivalent cell varied between 0.5 and 6.5% of the total prokaryotes, with extreme values observed in muddy sediment during October and January...

Aliphatic hydrocarbons and hopanes as biomarkers of the past 120 years sediment inputs in a coral reef lagoon (Tahiti, French Polynesia)

International Nuclear Information System (INIS)

Harris, P.A.; Fichez, R.; Fernandez, J.M.; Saliot, A.

1999-01-01

Sediment cores were sampled in four sites in the coral reef lagoon surrounding the city of Papeete, Tahiti, French Polynesia. Sediment cores were dated by mean of 210 Pb activity counting in order to reconstruct past trends in environmental changes. This paper focuses on the historical evolution of NAH and hopanes in a sediment core sampled in the harbour which yielded results over a period covering 120 years. Geochronoly results evidenced a large increase in sedimentation rates from 0.33 g.cm -2 .y -1 to 1.33 g.cm -2 .y -1 since 1967 ± 4 y

Heavy Metal Contents of Municipal and Rural Dumpsite Soils and Rate of Accumulation by Carica papaya and Talinum triangulare in Uyo, Nigeria

Directory of Open Access Journals (Sweden)

G. A. Ebong

2008-01-01

Full Text Available Dumpsites in Uyo and most cities in Nigeria are used nutrients rich soils for cultivating fruits and vegetables without regards to the risk of toxic metal pollution by the wastes. This development necessitated the research on the assessment of the impact of municipal and rural dumpsites on the metal levels of the underlying soils, the relationship between the dumpsite- soil metal content and the rate of bio-accumulation by plants, the effect of plant specie and plant part on the rate of metal uptake. Atomic absorption spectrophotometer was employed for the analysis of the samples and results obtained from municipal dumpsite soil indicated the following mean concentrations: Fe, 1711.20 μg/g; Pb, 43.28 ug/g; Zn, 88.34 ug/g; Ni, 12.18 ug/g; Cd, 14.10 ug/g and Cu, 56.33 ug/g. These concentrations were relatively higher than the following concentrations: Fe, 1016.98 ug/g; Pb, 18.57 ug/g; Zn, 57.90 ug/g; Ni, 7.98 ug/g; Cd, 9.25 ug/g and Cu, 33.70 ug/g recorded for the rural dumpsite soil. Consequently, plants grown on municipal dumpsites soil accumulated higher concentrations of the metals than those on rural dumpsites. Results obtained from this study also revealed that plants grown on dumpsite soils bio-accumulated higher metal concentrations than their counterparts obtained from normal agricultural soils. The ability of plants to bioaccumulate these metals were also observed as being different from one plant to the other and from one plant parts to the other. And apart from Fe and Zn which recorded higher concentrations in the leaves of the plants studied, other metals recorded higher concentrations in the roots. The general results obtained revealed that the levels of Cd in dumpsite-soil were above the standard while the levels of Cd and Pb in plants were also above the recommended levels in plants. The implications of these high concentrations of these metals in soil and plants have been discussed. Some useful recommendations on the proper

PBDD/Fs in surface sediments from the East River, China.

Science.gov (United States)

Ren, M; Peng, P A; Chen, D Y; Chen, P; Zhou, L

2009-09-01

The contamination status of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) was preliminarily investigated in surface sediments from the East River. The concentrations of eight 2,3,7,8-substituted tetra- to hexa- PBDD/Fs were found to be in the range of 0.32-110 (mean 13) pg g(-1) and the corresponding TEQ concentrations were 0.087-18 (mean 2) pg I-TEQ g(-1). All sediments were characterized by the dominant PBDFs. 2,3,4,7,8-PeBDF was the most important TEQ contributor, accounting for 47%-77% of the total I-TEQ of PBDD/Fs. PCDD/Fs contributed dominantly to the total TEQs of PCDD/Fs, PBDD/Fs and dioxin-like PCBs in most samples except of the sediment from the Shima River. The higher PBDD/F concentrations in the Shima River may be attributed to the use of BFRs in the electrical and electronics industries, which posed a potential risk of dioxins on ecological system.

Non-aromatic hydrocarbons in surface sediments near the Pearl River estuary in the South China Sea

International Nuclear Information System (INIS)

Gao Xuelu; Chen Shaoyong; Xie Xueliang; Long Aimin; Ma Fujun

2007-01-01

Surface sediment samples at 4 sites along an offshore transect from outer continental shelf off the Pearl River estuary to the shelf slope region of the northern South China Sea, have been analyzed for total organic carbon (TOC), total nitrogen (TN), solvent extractable organic matter (EOM) and non-aromatic hydrocarbons. TOC, TN and EOM show distinct spatial variations. Their highest values are all recorded at the shelf slope region. EOM varies from 18.70-38.58 μg g -1 dry sediment and accounts for 0.20-0.72% of the TOC contents. The non-aromatic hydrocarbons are an important fraction of EOM. Their contents range from 3.43-7.06 μg g -1 dry sediment. n-Alkanes with carbon number ranging from 15-38 are identified. They derive from both biogenic and petrogenic sources in different proportions. Results of isoprenoid hydrocarbons, hopanes and steranes also suggest possible petroleum contamination. - Anthropogenic activities have influences on the composition of non-aromatic hydrocarbons in the surface sediments of the northern South China Sea outer continental shelf

Quantification of methylmercury and geochemistry of mercury in sediments from a contaminated area of Descoberto (MG), Brazil

International Nuclear Information System (INIS)

Mendes, Louise Aparecida; Carvalho de Lena, Jorge; Magalhães do Valle, Cláudia; Fleming, Peter Marshall; Windmöller, Cláudia Carvalhinho

2016-01-01

In 2002, metallic Hg was found buried in a rural area of Descoberto city, Brazil. The origin of the Hg was a gold mining explotation plant established nearly one century ago. Although a number of studies have been conducted in order to assess the contamination of the area, none of them investigated the presence of methylated Hg in the hydric system. In this work methylmercury (CH_3Hg"+) was determined using gas chromatography-pyrolysis-atomic fluorescence detection (CG-pyro-AFS) in material from rain sedimentation boxes and stream sediments near the contaminated area. Total Hg concentration (HgT) along with the chemical speciation by thermo-desorption were performed. HgT in material from the sedimentation boxes was found to be very high, up to 41,580 μg kg"−"1, even in the rainy season, when in general HgT were much lower than in dry season. The samples from the Grama and Rico streams show a range of HgT from 5.8 to 266 μg kg"−"1. The thermo-desorption analysis showed predominance of Hg"2"+, possibly linked to organic sulfur, suggested by a good positive correlation between Hg"2"+, HgT, organic mater (OM) and total S. The CH_3Hg"+ concentration in stream sediment samples ranged from <0.07 to 1.87 μg kg"−"1 and in the samples of sedimentation boxes the concentrations were 1.33 and 8.0 μg kg"−"1 during dry season. The sample with the highest percentage of HgT as Hg"2"+ (98%) presented also the highest percentage of CH_3Hg"+ (0.7%). These are high values, showing that care should be taken to avoid the transport of this material to the hydrological system. Further studies on the transfer through the food chain would be very important. - Highlights: • Hg at concentrations that exceed quality values in sediments from Descoberto (MG-Brazil) has been confirmed. • Chemical speciation showed the predominance of Hg"2"+ species in the sediment samples. • It was observed the presence of CH_3Hg"+ in sedimentation boxes at concentrations up 8.0 μg

Toxicity of silicon carbide nanowires to sediment-dwelling invertebrates in water or sediment exposures

Science.gov (United States)

Mwangi, Joseph N.; Wang, Ning; Ritts, Andrew; Kunz, James L.; Ingersoll, Christopher G.; Li, Hao; Deng, Baolin

2011-01-01

Silicon carbide nanowires (SiCNW) are insoluble in water. When released into an aquatic environment, SiCNW would likely accumulate in sediment. The objective of this study was to assess the toxicity of SiCNW to four freshwater sediment-dwelling organisms: amphipods (Hyalella azteca), midges (Chironomus dilutus), oligochaetes (Lumbriculus variegatus), and mussels (Lampsilis siliquoidea). Amphipods were exposed to either sonicated or nonsonicated SiCNW in water (1.0 g/L) for 48 h. Midges, mussels, and oligochaetes were exposed only to sonicated SiCNW in water for 96 h. In addition, amphipods were exposed to sonicated SiCNW in whole sediment for 10 d (44% SiCNW on dry wt basis). Mean 48-h survival of amphipods exposed to nonsonicated SiCNW in water was not significantly different from the control, whereas mean survival of amphipods exposed to sonicated SiCNW in two 48-h exposures (0 or 15% survival) was significantly different from the control (90 or 98% survival). In contrast, no effect of sonicated SiCNW was observed on survival of midges, mussels, or oligochaetes. Survival of amphipods was not significantly reduced in 10-d exposures to sonicated SiCNW either mixed in the sediment or layered on the sediment surface. However, significant reduction in amphipod biomass was observed with the SiCNW either mixed in sediment or layered on the sediment surface, and the reduction was more pronounced for SiCNW layered on the sediment. These results indicated that, under the experimental conditions, nonsonicated SiCNW in water were not acutely toxic to amphipods, sonicated SiCNW in water were acutely toxic to the amphipods, but not to other organisms tested, and sonicated SiCNW in sediment affected the growth but not the survival of amphipods.

Application and expression of HSV gG1 protein from a recombinant strain.

Science.gov (United States)

Yan, Hua; Yan, Huishen; Huang, Tao; Li, Guocai; Gong, Weijuan; Jiao, Hongmei; Chen, Hongju; Ji, Mingchun

2010-11-01

According to the homologous sequence of glycoprotein G1 (gG1) genes from different strains of herpes simplex virus type 1 (HSV-1), a pair of primers was designed to amplify the gG1 gene fragment by PCR. Both the PCR product and the pGEX-4T-1 vector were digested with EcoR I and Sal I. The gG1 gene fragment was subcloned into the digested pGEX-4T-1 vector to construct a recombinant plasmid (pGEX-4T-1-gG1). The resultant plasmid was identified by dual-enzyme digestion and sequence analysis, and then transformed into Escherichia coli BL21 for expression under the induction of isopropyl β-D-1-thiogalactoside (IPTG). The expressed GST-gG1 fragment was detected by SDS-PAGE and purified by affinity chromatography. The properties of GST-gG1 fragment were evaluated by immunoblot analysis. Enzyme-linked immunosorbent assays (ELISAs) based on the GST-gG1 fragment were used for determining IgG or IgM to HSV-1. The GST-gG1 fragment-specific ELISA was also compared with ELISA with whole-HSV-1 antigen and commercial ELISA kits. The gG1-specific IgG and IFN-γ producing CD8+ T cells were induced in mice immunized with the GST-gG1 fragment. These results indicated that the GST-gG1 fragment could be used for replacing whole-virus antigen to detect IgM and IgG to HSV-1 in human sera, which provided a strategy for developing vaccines to protect HSV-1 infection using gG1 fragment. Copyright © 2010 Elsevier B.V. All rights reserved.

Bioleaching of heavy metal polluted sediment: influence of sediment properties. Pt. 2

Energy Technology Data Exchange (ETDEWEB)

Loeser, C. [Technische Universitaet Dresden, Institut fuer Lebensmittel- und Bioverfahrenstechnik, Bergstrasse 120, D-01062 Dresden (Germany); Zehnsdorf, A. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Umwelt- und Biotechnologisches Zentrum, Permoserstrasse 15, D-04318 Leipzig (Germany); Hoffmann, P.; Seidel, H. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Department Bioremediation, Permoserstrasse 15, D-04318 Leipzig (Germany)

2006-08-15

A remediation process for heavy metal polluted sediment has previously been developed, in which the heavy metals are removed from the sediment by solid-bed bioleaching using sulfuric acid as a leaching agent arising from added elemental sulfur (S{sup 0}). This process has been engineered with Weisse Elster River sediment (dredged near Leipzig, Germany), as an example. Here, six heavy metal polluted sediments originating from various bodies of water in Germany were subjected to bioleaching to evaluate the applicability of the developed process on sediment of different nature: each sediment was mixed with 2 % S{sup 0}, suspended in water and then leached under identical conditions. The buffer characteristics of each sediment were mainly governed by its carbonate and Ca content, i.e., by its geological background, the redox potential and oxidation state depended on its pre-treatment (e.g., on land disposal), while the pH value was influenced by both. The added S{sup 0} was quickly oxidized by the indigenous microbes even in slightly alkaline sediment. The microbially generated H{sub 2}SO{sub 4} accumulated in the aqueous phase and was in part precipitated as gypsum. Significant acidification and heavy metal solubilization only occurred with sediment poor in buffer substances. With the exception of one sediment, the behavior in bioleaching correlated well with the behavior in titration with H{sub 2}SO{sub 4}. Since the content in carbonate seemed to be the most important factor deciding on the leachability of a sediment, oxic Weisse Elster River sediment was mixed with 2 % S{sup 0} and 0 to 100 g/kg of ground limestone to simulate various buffer capacities, suspended in water and then leached. The lime did not inhibit microbial S{sup 0} oxidation but generated a delay in acidification due to neutralization of formed H{sub 2}SO{sub 4}, where the pH only started to decrease when the lime was completely consumed. The more lime the sediment contained, the longer this lag

Analyzing the variability of sediment yield: A case study from paired watersheds in the Upper Blue Nile basin, Ethiopia

Science.gov (United States)

Ebabu, Kindiye; Tsunekawa, Atsushi; Haregeweyn, Nigussie; Adgo, Enyew; Meshesha, Derege Tsegaye; Aklog, Dagnachew; Masunaga, Tsugiyuki; Tsubo, Mitsuru; Sultan, Dagnenet; Fenta, Ayele Almaw; Yibeltal, Mesenbet

2018-02-01

Improved knowledge of watershed-scale spatial and temporal variability of sediment yields (SY) is needed to design erosion control strategies, particularly in the most severely eroded areas. The present study was conducted to provide this knowledge for the humid tropical highlands of Ethiopia using the Akusity and Kasiry paired watersheds in the Guder portion of the Upper Blue Nile basin. Discharge and suspended sediment concentration data were monitored during the rainy season of 2014 and 2015 using automatic flow stage sensors, manual staff gauges and a depth-integrated sediment sampler. The SY was calculated using empirical discharge-sediment curves for different parts of each rainy season. The measured mean daily sediment concentration differed greatly between years and watersheds (0.51 g L- 1 in 2014 and 0.92 g L- 1 in 2015 for Kasiry, and 1.04 g L- 1 in 2014 and 2.20 g L- 1 in 2015 for Akusity). Sediment concentrations at both sites decreased as the rainy season progressed, regardless of the rainfall pattern, owing to depletion of the sediment supply and limited transport capacity of the flows caused by increased vegetation cover. Rainy season SYs for Kasiry were 7.6 t ha- 1 in 2014 and 27.2 t ha- 1 in 2015, while in Akusity SYs were 25.7 t ha- 1 in 2014 and 71.2 t ha- 1 in 2015. The much larger values in 2015 can be partly explained by increased rainfall and larger peak flow events. The magnitude and timing of peak flow events are major determinants of the amount and variability of SYs. Thus, site-specific assessment of such events is crucial to reveal SY dynamics of small watersheds in tropical highland environments.

Study of cadmium, lead and tin distribution in surface marine sediment samples from Ria de Arousa (NW of Spain)

International Nuclear Information System (INIS)

Barciela-Alonso, M.C.; Pazos-Capeans, P.; Regueira-Miguens, M.E.; Bermejo-Barrera, A.; Bermejo-Barrera, P.

2004-01-01

In this work a study of the Cd, Pb and Sn content in marine surface sediment from the Ria de Arousa has been realised. For this, 21 sediment samples were taken in triplicate, lyophilised and sieved, and the fraction -1 Cd, 26.5-91.3 μg g -1 Pb and 5.0-20.8 μg g -1 Sn. The highest concentrations of these metals are in the inner part of the Ria, near to the port and urban nucleus such as Vilagarcia or Rianxo, and decrease toward the mouth of the Ria

Are styrene oligomers in coastal sediments of an industrial area aryl hydrocarbon-receptor agonists?

Science.gov (United States)

Hong, Seongjin; Lee, Junghyun; Lee, Changkeun; Yoon, Seo Joon; Jeon, Seungyeon; Kwon, Bong-Oh; Lee, Jong-Hyeon; Giesy, John P; Khim, Jong Seong

2016-06-01

Effect-directed analysis (EDA) was performed to identify the major aryl hydrocarbon receptor (AhR) agonists in sediments collected from a highly industrialized area (Lake Shihwa, Korea). Great AhR-mediated potencies were found in fractions containing aromatic compounds with log Kow values of 5-8, and relatively great concentrations of styrene oligomers (SOs) and polycyclic aromatic hydrocarbons (PAHs) were detected in those fractions. Until now, there was little information on occurrences and toxic relative potencies (RePs) of SOs in coastal environments. In the present study; i) distributions and compositions, ii) AhR binding affinities, and iii) contributions of SOs to total AhR-mediated potencies were determined in coastal sediments. Elevated concentrations of 10 SOs were detected in sediments of inland creeks ranging from 61 to 740 ng g(-1) dry mass (dm), while lesser concentrations were found in inner (mean = 33 ng g(-1) dm) and outer regions (mean = 25 ng g(-1) dm) of the lake. Concentrations of PAHs in sediments were comparable to those of SOs. 2,4-diphenyl-1-butene (SD3) was the predominant SO analogue in sediments. SOs and PAHs were accumulated in sediments near sources, and could not be transported to remote regions due to their hydrophobicity. RePs of 3 SOs could be derived, which were 1000- to 10,000-fold less than that of one representative potent AhR active PAH, benzo[a]pyrene. Although concentrations of SOs in sediments were comparable to those of PAHs, the collective contribution of SOs to total AhR-mediated potencies were rather small (coastal environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Current status and historical variations of phthalate ester (PAE) contamination in the sediments from a large Chinese lake (Lake Chaohu).

Science.gov (United States)

Kang, Lei; Wang, Qing-Mei; He, Qi-Shuang; He, Wei; Liu, Wen-Xiu; Kong, Xiang-Zhen; Yang, Bin; Yang, Chen; Jiang, Yu-Jiao; Xu, Fu-Liu

2016-06-01

The residual levels of phthalate esters (PAEs) in the surface and two core sediments from Lake Chaohu were measured with a gas chromatograph-mass spectrometer (GC-MS). The temporal-spatial distributions, compositions of PAEs, and their effecting factors were investigated. The results indicated that di-n-butyl phthalate (DnBP), diisobutyl phthalate (DIBP), and di(2-ethylhexyl) phthalate (DEHP) were three dominant PAE components in both the surface and core sediments. The residual level of total detected PAEs (∑PAEs) in the surface sediments (2.146 ± 2.255 μg/g dw) was lower than that in the western core sediments (10.615 ± 9.733 μg/g) and in the eastern core sediments (5.109 ± 4.741 μg/g). The average content of ∑PAEs in the surface sediments from the inflow rivers (4.128 ± 1.738 μg/g dw) was an order of magnitude higher than those from the lake (0.323 ± 0.093 μg/g dw), and there were similar PAE compositions between the lake and inflow rivers. This finding means that there were important effects of PAE input from the inflow rivers on the compositions and distributions of PAEs in the surface sediments. An increasing trend was found for the residual levels of ΣPAEs, DnBP, and DIBP from the bottom to the surface in both the western and eastern core sediments. Increasing PAE usage with the population growth, urbanization, and industrial and agricultural development in Lake Chaohu watershed would result in the increasing production of PAEs and their resulting presence in the sediments. The significant positive relationships were also found between the PAE contents and the percentage of sand particles, as well as TOC contents in the sediment cores.

Phenyltins in Surface Sediments of the Visakhapatnam Harbour, India

Digital Repository Service at National Institute of Oceanography (India)

Jadhav, S.S.; Bhosle, S.N.; Venkat, K.; Sawant, S.S.

and TPT varied between 1–26, 3–28, and 0.31–145 ng Sn g sup(-1) dry wt, respectively. Phenyltin concentrations were influenced by ship related activities, agricultural waste and sewage. These phenyltin concentrations indicate sediments are contaminated...

Synergistic effects of diuron and sedimentation on photosynthesis and survival of crustose coralline algae

Energy Technology Data Exchange (ETDEWEB)

Harrington, Lindsay [Australian Institute of Marine Science, Townsville, QLD 4810 (Australia) and James Cook University, Townsville, QLD 4811 (Australia)]. E-mail: l.harrington@aims.gov.au; Fabricius, Katharina [Australian Institute of Marine Science, Townsville, QLD 4810 (Australia)]. E-mail: k.fabricius@aims.gov.au; Eaglesham, Geoff [Queensland Health Scientific Services, 39 Kessels Road, Coopers Plains 4108 (Australia); Negri, Andrew [Australian Institute of Marine Science, Townsville, QLD 4810 (Australia)

2005-07-01

Effects of short-term exposure to sedimentation and diuron, separately and in combination, on the photophysiology and survival of crustose coralline algae (CCA) were examined in controlled time-course experiments, using pulse-amplitude modulation (PAM) chlorophyll fluorometry. These experiments indicated that the effects of sediments and diuron, when applied in isolation, were often reversible, with recovery time dependant upon sediment type and diuron concentration. Exposure to fine (<63 {mu}m grain size), nutrient-rich estuarine sediments reduced effective quantum yields ({delta}F/F {sub m'}) of photosystem II in CCA species more than exposure to the same amount of fine (<63 {mu}m grain size) calcareous sediments. Significant inhibition of photosynthesis ({delta}F/F {sub m'}) was also observed at diuron concentrations 2.9 {mu}g L{sup -1}. Fine estuarine sediments in combination with 0.79 {mu}g L{sup -1} dissolved diuron, caused yields ({delta}F/F {sub m'}) to drop by 60% compared with controls after 24 h. The combined exposure to sediments and diuron also retarded recovery, thus {delta}F/F {sub m'} values were still only 60% of the controls after 9 days recovery in clean seawater. Mortality of CCA was observed in some fragments treated with combinations of sediment and diuron. Our results suggest that sediment deposition and exposure to diuron can negatively affect the photosynthetic activity of CCA, with sedimentation stress being significantly enhanced by the presence of trace concentrations of diuron.

Heavy metal contaminant remediation study of western Xiamen Bay sediment, China: laboratory bench scale testing results.

Science.gov (United States)

Zhang, Luoping; Feng, Huan; Li, Xiaoxia; Ye, Xin; Jing, Youhai; Ouyang, Tong; Yu, Xingtian; Liang, Rongyuan; Chen, Weiqi

2009-12-15

A surface sediment sample (metal removal, whereas agitation, aeration and rotation of the samples in chemical complexation solutions yield much better metal removal efficiency (up to 90%). A low pH condition (e.g., pHliquid ratio (e.g., S:L=1:50) could increase metal removal efficiency. The experimental results suggest that 0.20 M (NH4)2C2O4+0.025 M EDTA combination with solid:liquid ratio=1:50 and 0.50 M ammonium acetate (NH4Ac)+0.025 M EDTA combination with solid:liquid ratio=1:50 are the most effective methods for metal removal from the contaminated sediments. This research provides additional useful information for sediment metal remediation technology development.

Sorption of alkylphenols on Ebro River sediments: Comparing isotherms with field observations in river water and sediments

International Nuclear Information System (INIS)

Navarro, Alicia; Endo, Satoshi; Gocht, Tilman; Barth, Johannes A.C.; Lacorte, Silvia; Barcelo, Damia; Grathwohl, Peter

2009-01-01

This study reports sorption isotherms of the endocrine disruptors nonylphenol (NP) and octylphenol (OP) in three sediment samples from the Ebro River basin (NE Spain), with organic carbon fractions (f OC ) ranging from 0.0035 to 0.082 g OC g -1 . All isotherms were fitted to the Freundlich model with slightly nonlinear exponents ranging from 0.80 to 0.94. The solubility of the compounds as well as the organic carbon (OC) content had the strongest influences on the sorption behavior of these compounds. Comparison of the laboratory-spiked samples with the native contamination of NP of 45 water and concurrent sediment samples resulted in reasonable matches between both data sets, even though the lowest concentrations in the field were not completely reached in laboratory tests. This good agreement indicates that sorption laboratory data can be extrapolated to environmental levels and therefore the distribution of nonylphenol between sediments and water can be predicted with a precision of one order of magnitude. Furthermore, laboratory experiments with simultaneous loading of NP and OP revealed negligible competition for sorption sites at low concentrations. - Laboratory sorption of nonylphenol compared to field concentrations showed good agreements

Sorption of alkylphenols on Ebro River sediments: Comparing isotherms with field observations in river water and sediments

Energy Technology Data Exchange (ETDEWEB)

Navarro, Alicia [Center of Applied Geoscience, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen (Germany); Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, 08034 Barcelona (Spain)], E-mail: anoqam@iiqab.csic.es; Endo, Satoshi; Gocht, Tilman [Center of Applied Geoscience, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen (Germany); Barth, Johannes A.C. [Center of Applied Geoscience, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen (Germany); Lehrstuhl fuer Angewandte Geologie, GeoZentrum Nordbayern, Universitaet Erlangen-Nuernberg, Schlossgarten 5, 91054 Erlangen (Germany); Lacorte, Silvia [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, 08034 Barcelona (Spain); Barcelo, Damia [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, 08034 Barcelona (Spain); Institut Catala de Recerca de l' Aigua (ICRA), Parc Cientific i Tecnologic de la Universitat de Girona, Pic de Peguera, 15, 17003 Girona (Spain); Grathwohl, Peter [Center of Applied Geoscience, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen (Germany)

2009-02-15

This study reports sorption isotherms of the endocrine disruptors nonylphenol (NP) and octylphenol (OP) in three sediment samples from the Ebro River basin (NE Spain), with organic carbon fractions (f{sub OC}) ranging from 0.0035 to 0.082 g{sub OC} g{sup -1}. All isotherms were fitted to the Freundlich model with slightly nonlinear exponents ranging from 0.80 to 0.94. The solubility of the compounds as well as the organic carbon (OC) content had the strongest influences on the sorption behavior of these compounds. Comparison of the laboratory-spiked samples with the native contamination of NP of 45 water and concurrent sediment samples resulted in reasonable matches between both data sets, even though the lowest concentrations in the field were not completely reached in laboratory tests. This good agreement indicates that sorption laboratory data can be extrapolated to environmental levels and therefore the distribution of nonylphenol between sediments and water can be predicted with a precision of one order of magnitude. Furthermore, laboratory experiments with simultaneous loading of NP and OP revealed negligible competition for sorption sites at low concentrations. - Laboratory sorption of nonylphenol compared to field concentrations showed good agreements.

Distribution of nutrients in fluvial sediment of the Itajai-Açu river, Blumenau, SC, Brazil

Directory of Open Access Journals (Sweden)

Joseane Susin

2010-04-01

Full Text Available This study verified the occurrence of nitrogen (Ntotal, NH4+, NO3- e NO2- and phosphorus (Ptotal in fluvial sediments of the Itajaí-Açu River, on the river's course in the urban area of Blumenau city. At the eight sites where the samples were collected, the total nitrogen presented values below those recommended in the CONAMA nº 344/2004 Resolution for sediments which is 4,800.00 µg g-1, with values of 350.00 µg g-1 to 2,100.00 µg g-1. The total phosphorus also presented values below the one recommended by the CONAMA nº 344/2004 Resolution for sediments which is 2,000.00 µg g-1. The values found for total phosphorus varied from 61.50 µg g-1 to 378.00 µg g-1, and were determined as the addition of the organic and the inorganic phosphorus. As for the summation of the NH4+, NO3- and NO2- ions at the eight sites where the sample were collected, it can be observed a greater quantity of these ions in any collecting site and in the other sites the values were low. The content values for the NO2- ions for the studied eight sites were low when compared to the values observed for the NH4+ ion.

Gelatin methacrylamide as coating material in cell culture.

Science.gov (United States)

Egger, Michael; Tovar, Günter E M; Hoch, Eva; Southan, Alexander

2016-06-13

Unmodified gelatin (uG) is widely used as a coating material in cell culture for improving surface properties. In this study, the authors investigated if gelatin methacrylamide (GM) with a medium degree of methacrylamide modification (GM1.5) and a high degree of methacrylamide modification (GM4) are equally suitable for this purpose. Therefore, gold surfaces were coated with uG, GM1.5, and GM4 by adsorption of the polymers on the surfaces. Coating success was confirmed by spectroscopic ellipsometry, contact angle measurements, surface plasmon resonance spectroscopy (SPRS), and atomic force microscopy (AFM). The authors found that upon adsorption of uG, GM1.5, a nd GM4 on gold, thin films with thicknesses of 2.95 nm, 2.50 nm, and 2.26 nm were formed. The coated surfaces showed advancing contact angles of 46° (uG and GM1.5) and 52° (GM4) without alteration of the surface roughness determined by AFM. Protein adsorption taking place on the coated surfaces was measured during contact of the surfaces with fetal calf serum by SPRS. Protein adsorption on the coated surfaces was reduced by the factor of 6.4 (uG), 5.4 (GM1.5), and 4.6 (GM4) compared to gold surfaces. Human fibroblasts cultured on the surfaces showed excellent viability shown by water soluble tetrazolium salt assay as well as live/dead staining with propidium iodide and fluorescein diacetate. No cytotoxic effects of the GM coated surfaces were observed, giving rise to the conclusion that GMs are suitable materials as coatings in cell culture.

Environmental risk assessment of triclosan and ibuprofen in marine sediments using individual and sub-individual endpoints.

Science.gov (United States)

Pusceddu, F H; Choueri, R B; Pereira, C D S; Cortez, F S; Santos, D R A; Moreno, B B; Santos, A R; Rogero, J R; Cesar, A

2018-01-01

The guidelines for the Environmental Risk Assessment (ERA) of pharmaceuticals and personal care products (PPCP) recommend the use of standard ecotoxicity assays and the assessment of endpoints at the individual level to evaluate potential effects of PPCP on biota. However, effects at the sub-individual level can also affect the ecological fitness of marine organisms chronically exposed to PPCP. The aim of the current study was to evaluate the environmental risk of two PPCP in marine sediments: triclosan (TCS) and ibuprofen (IBU), using sub-individual and developmental endpoints. The environmental levels of TCS and IBU were quantified in marine sediments from the vicinities of the Santos submarine sewage outfall (Santos Bay, São Paulo, Brazil) at 15.14 and 49.0 ng g -1 , respectively. A battery (n = 3) of chronic bioassays (embryo-larval development) with a sea urchin (Lytechinus variegatus) and a bivalve (Perna perna) were performed using two exposure conditions: sediment-water interface and elutriates. Moreover, physiological stress through the Neutral Red Retention Time Assay (NRRT) was assessed in the estuarine bivalve Mytella charruana exposed to TCS and IBU spiked sediments. These compounds affected the development of L. variegatus and P. perna (75 ng g -1 for TCS and 15 ng g -1 for IBU), and caused a significant decrease in M. charruana lysosomal membrane stability at environmentally relevant concentrations (0.08 ng g -1 for TCS and 0.15 ng g -1 for IBU). Chemical and ecotoxicological data were integrated and the risk quotient estimated for TCS and IBU were higher than 1.0, indicating a high environmental risk of these compounds in sediments. These are the first data of sediment risk assessment of pharmaceuticals and personal care products of Latin America. In addition, the results suggest that the ERA based only on individual-level and standard toxicity tests may overlook other biological effects that can affect the health of marine organisms

Microbial diversity on sedimentated rice fields due to coal mining activities in Tenggarong Seberang subdistrict of Kutai Kartanegara

Science.gov (United States)

Rosfiansyah; Sopialena

2018-04-01

The results showed that on upland rice fields with sediment found five genus of fungus with number of colonies 4.0 x 103 cfu/g to 9.3 x 104 cfu/g; three bacterial families with number of colonies 7,1 x 104 cfu/g to 2,8 x 105 cfu/g; and five genera of nematodes with the amount of 2.6 x 102/kg of soil to 1.1 x103/kg of soil. In unpolished upland rice fields were found four genus of fungus with colonies of 2.4 x 103 cfu/g to 8.4 x 104 cfu/g, three bacterial families with number of colonies 1.2 x 105 cfu/g to 2.7 x 105 cfu/g and four genera of nematodes with the amount of 9.6 x 102/kg of soil to 1.1 x103/kg of soil. The most common microbes are Aspergillus, Cladosporium, Penicillium, Phytium and Trichoderma (fungi), Achromobacteraceae, Brevibacteriaceae, Micrococcaceae (Bacteria), as well as Dorylaimus, Hemicycliophora, Mononchus, Meloidogyne, Paratrichodorus, Radopholus, Rotylenchulus, Rhabditis, Seinura and Trichodorus (Nematodes). Fungi, bacteria and nematodes have a good role in the process of soil decomposition. The results of soil chemical analysis showed that soil fertility is lower in upland rice fields with sediments compare to those without sediment.

Uranium geochemistry on the Amazon shelf: Evidence for uranium release from bottom sediments

International Nuclear Information System (INIS)

McKee, B.A.; DeMaster, D.J.; Nittrouer, C.A.

1987-01-01

In Amazon-shelf waters, as salinity increases to 36.5 x 10 -3 , dissolved uranium activities increase to a maximum of 4.60 dpm 1 -1 . This value is much higher than the open-ocean value (2.50 dpm 1 -1 ), indicating a source of dissolved uranium to shelf waters in addition to that supplied from open-ocean and riverine waters. Uranium activities are much lower for surface sediments in the Amazon-shelf sea bed (mean: 0.69 ± .09 dpm g -1 ) than for suspended sediments in the Amazon river (1.82 dpm g -1 ). Data suggest that the loss of particulate uranium from riverine sediments is probably the result of uranium desorption from the ferric-oxyhydroxide coatings on sediment particles, and/or uranium release by mobilization of the ferric oxyhydroxides. The total flux of dissolved 238 U from the Amazon shelf (about 1.2 x 10 15 dpm yr -1 ) constitutes about 15% of uranium input to the world ocean, commensurate to the Amazon River's contribution to world river-water discharge. Measurement of only the riverine flux of dissolved 238 U underestimates, by a factor of about 5, the flux of dissolved 238 U from the Amazon shelf to the open ocean

Copper clean-up procedure for ultrasonic extraction and analysis of pyrethroid and phenylpyrazole pesticides in sediments by gas chromatography-electron capture detection

International Nuclear Information System (INIS)

Wu Jun; Lin Youjian; Lu Jian; Wilson, Chris

2011-01-01

A rapid ultrasonic extraction method coupled with a heated-copper clean-up procedure for removing interfering constituents was developed for analyzing pyrethroid and phenylpyrazole pesticides in sediments. Incubation of the 60 mL extract with 12 g copper granules at 60 o C for 2 h was determined to be the optimal conditions for removing the interfering constituents. Eleven pyrethroid and phenylpyrazole pesticides were spiked into sediment samples to determine the effectiveness of the ultrasonic extraction method. The average recoveries of pyrethroids and phenylpyrazoles in sediment at 4 o C storage on day 0, 1, 7, 14, and 21 ranged from 98.6 to 120.0%, 79.2 to 116.0%, 85.0 to 119.7%, 93.6 to 118.7%, and 92.1 to 118.2%, respectively, with all percent relative standard deviations less than 10% (most o C. Recoveries of the pesticides ranged from 98.6% to 120.0% for lowest fortification level (2-16 μg kg -1 ), from 97.8% to 117.9% for middle fortification level (10-80 μg kg -1 ), and from 94.3% to 118.1% for highest fortification level (20-160 μg kg -1 ). Relative standard deviations of pesticide recoveries were usually less than 7%. Method detection limits of target pesticides ranged from 0.22 μg kg -1 to 3.72 μg kg -1 . Furthermore, field sediment samples collected from four residential lakes during a three-month monitoring period were analyzed to evaluate the effectiveness of this method. Bifenthrin was detected in all of sediment samples (highest concentration 260.33 ± 41.71 μg kg -1 , lowest concentration 5.68 ± 0.38 μg kg -1 ), and fipronil sulfone was detected at least once in sediment samples collected from three sites with concentrations ranging from 1.73 ± 0.53 to 7.53 ± 0.01 μg kg -1 . - Highlights: → A rapid extraction and copper-based clean-up method was developed. → Recoveries after storage at 4 o C for 21 d ranged from 79.2 to 120.0%. → Percent relative standard deviations less than 10% (most -1 to 3.72 μg kg -1 .

Determination of DDT and metabolites in surface water and sediment using LLE, SPE, ACE and SE.

Science.gov (United States)

Sibali, Linda L; Okonkwo, Jonathan O; Zvinowanda, Caliphs

2009-12-01

Surface water and sediment samples collected from Jukskei River in South Africa, were subjected to different extraction techniques, liquid-liquid (LLE), solid-phase extraction (SPE), activated carbon extraction (ACE) and soxhlet extraction (SE) for sediment. The samples were extracted with dichloromethane, cleaned in a silica gel column and the extracts quantified using a Varian 3800 GC-ECD. The percentage recovery test for 2,4'DDT, DDE and DDD and 4,4'DDT, DDE and DDD in water ranged from 80%-96% and 76%-95% (LLE); 56%-76% and 56%-70% (SPE) and 75%-84% (ACE), respectively; while that recoveries for sediment samples varied from 65%-95% for 2,4'DDT, DDE and DDD and 80%-91% for 4,4'DDT, DDE and DDD. The high recoveries exhibited by ACE compared very well with LLE and SE. This was not the case with SPE which exhibited the lowest value of recoveries for both 2,4 and 4,4'DDD, DDE and DDT standard samples. The mean concentrations of DDT and metabolites ranged from nd-1.10 μg/L, nd-0.80 μg/L, nd-1.21 μg/L and 1.92 μg/L for LLE, SPE, ACE and SE, respectively. The total DDT (2,4' and 4,4'-DDT) in water and sediment samples ranged from 1.20-3.25 μg/L and 1.82-5.24 μg/L, respectively. The low concentrations of the DDT metabolites obtained in the present study may suggest a recent contamination of the river by DDT.

Sediment exchange to mitigate pollutant exposure in urban soil.

Science.gov (United States)

Walsh, Daniel; Glass, Katherine; Morris, Samantha; Zhang, Horace; McRae, Isabel; Anderson, Noel; Alfieri, Alysha; Egendorf, Sara Perl; Holberton, Shana; Owrang, Shahandeh; Cheng, Zhongqi

2018-05-15

Urban soil is an ongoing source for lead (Pb) and other pollutant exposure. Sources of clean soil that are locally-available, abundant and inexpensive are needed to place a protective cover layer over degraded urban soil to eliminate direct and indirect pollutant exposures. This study evaluates a novel sediment exchange program recently established in New York City (NYC Clean Soil Bank, CSB) and found that direct exchange of surplus sediment extracted from urban construction projects satisfies these criteria. The CSB has high total yield with 4.2 × 10 5  t of sediment exchanged in five years. Average annual yield (8.5 × 10 4  t yr -1 ) would be sufficient to place a 15-cm (6-in.) sediment cover layer over 3.2 × 10 5  m 2 (80 acres) of impacted urban soil or 1380 community gardens. In a case study of sediment exchange to mitigate community garden soil contamination, Pb content in sediment ranged from 2 to 5 mg kg -1 . This sediment would reduce surface Pb concentrations more than 98% if it was used to encapsulate soil with Pb content exceeding USEPA residential soil standards (400 mg kg -1 ). The maximum observed sediment Pb content is a factor of 42 and 71 lower than median surface soil and garden soil in NYC, respectively. All costs (transportation, chemical testing, etc.) in the CSB are paid by the donor indicating that urban sediment exchange could be an ultra-low-cost source for urban soil mitigation. Urban-scale sediment exchange has advantages over existing national- or provincial-scale sediment exchanges because it can retain and upcycle local sediment resources to attain their highest and best use (e.g. lowering pollutant exposure), achieve circular urban materials metabolism, improve livability and maximize urban sustainability. Published by Elsevier Ltd.

New Seeds are Resistant to Wheat Stem Rust (Ug99) Multinational Programme Supported by FAO and IAEA

International Nuclear Information System (INIS)

2013-01-01

Full text: A multinational effort supported by the International Atomic Energy Agency and the U.N. Food and Agriculture Organization marked a key milestone this week when a Kenyan university debuted two new varieties of disease-resistant wheat to the nation's farmers. Over the past two days, thousands of Kenyan farmers have visited Eldoret University in western Kenya for a two-day agriculture fair highlighting the latest farming technologies. Supporting the development of the new varieties were the IAEA's Technical Cooperation Department and the Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture. They manage an interregional Technical Cooperation project to develop varieties of wheat that are resistant to a devastating type of fungus, causing a disease known as wheat stem rust. Wheat stem rust under control for over 30 years, but a resurgence of the disease was discovered in 1999 in Uganda that swiftly spread to neighbouring Kenya. The wheat stem rust, caused by the strain of the fungus known as Ug99, named after its place and year of origin, has since spread to Iran, Yemen and South Africa and threatens crops as far away as India as spores are carried by wind. Parasitic rusts threaten global wheat production, reducing plant growth and crop yields. The disease can destroy up to 70-100 percent of the yield of wheat crop if not prevented. 'Improving food security in developing countries through the use of nuclear techniques is an important priority of the IAEA', said IAEA Director General Yukiya Amano. 'I am pleased that we have been able to make an important contribution to fighting wheat rust'. 'Wheat rusts, particularly the Ug99 strain, are a major threat to food security because rust epidemics can result in devastating yield losses. This international project involving affected countries, plant scientists and breeders and international organizations is a major breakthrough. It clearly shows the benefits of FAO/IAEA collaboration and that

Hourly and daily variation of sediment redox potential in tidal wetland sediments

Science.gov (United States)

Catallo, W. James

1999-01-01

Variation of electrochemical oxidation-reduction (redox) potential was examined in surface salt march sediments under conditions of flooding and tidal simulation in mesocosms and field sites. Time series were generated of redox potential measured in sediment profiles at 2-10 cm depth using combination Pt-Ag/AgCl (ORP) electrodes. Redox potential data were acquired at rapid rates (1-55 samples/h) over extended periods (3-104 days) along with similar times series of temperature (water, air, soil) and pH. It was found that redox potential vaired as a result of water level changes and was unrelated to diurnal changes in temperature or pH, the latter of which changed by 370 mV redox potential decrease in under 48 hours). Attenuatoin of microbial activity by [gamma] y-radiation and toxic chemicals elimintated this response. In tidal salt marsh mesocosms where the sediment-plant assemblages were exposed to a simulated diurnal tide, redox potenial oscillations of 40-300 mV amplitude were recoded that has the same periodicity as the flood-drain cycle. Periodic redoc potential time series were observed repeatedly in sediments receiving tidal pulsing but not in those sediments exposed to static hydrological conditions. Data collected over 12 days from a coastal marsh site experiencing diurnal tides showed similar fluctuations in redox potential. Data from the experimentents indicated that (a) redox potential can be a dynamic, nonlinear variable in coastal and estuarine wetland sediments over hourly and daily scales, and the designs of biogeochemical experiments should reflect this, (b) redox potential can change rapidly and signigicantly in coastal wetland sediments in response of flooding and draining, (c) microbial community processes are primarily determinants of the time course of redox potential in wetland sediments, and elimination of inhibition of microbial activity (e.g. by pollutants) can significantly alter that behavior, and (d) fast redox potential dynamics appear

Diurnal variation in rates of calcification and carbonate sediment dissolution in Florida Bay

Science.gov (United States)

Yates, K.K.; Halley, R.B.

2006-01-01

Water quality and circulation in Florida Bay (a shallow, subtropical estuary in south Florida) are highly dependent upon the development and evolution of carbonate mud banks distributed throughout the Bay. Predicting the effect of natural and anthropogenic perturbations on carbonate sedimentation requires an understanding of annual, seasonal, and daily variations in the biogenic and inorganic processes affecting carbonate sediment precipitation and dissolution. In this study, net calcification rates were measured over diurnal cycles on 27 d during summer and winter from 1999 to 2003 on mud banks and four representative substrate types located within basins between mud banks. Substrate types that were measured in basins include seagrass beds of sparse and intermediate density Thalassia sp., mud bottom, and hard bottom communities. Changes in total alkalinity were used as a proxy for calcification and dissolution. On 22 d (81%), diurnal variation in rates of net calcification was observed. The highest rates of net carbonate sediment production (or lowest rates of net dissolution) generally occurred during daylight hours and ranged from 2.900 to -0.410 g CaCO3 m-2 d-1. The lowest rates of carbonate sediment production (or net sediment dissolution) occurred at night and ranged from 0.210 to -1.900 g CaCO3 m -2 night-1. During typical diurnal cycles, dissolution during the night consumed an average of 29% of sediment produced during the day on banks and 68% of sediment produced during the day in basins. Net sediment dissolution also occurred during daylight, but only when there was total cloud cover, high turbidity, or hypersalinity. Diurnal variation in calcification and dissolution in surface waters and surface sediments of Florida Bay is linked to cycling of carbon dioxide through photosynthesis and respiration. Estimation of long-term sediment accumulation rates from diurnal rates of carbonate sediment production measured in this study indicates an overall average

Analytical study on U/G coal mine CPT and inferences

Energy Technology Data Exchange (ETDEWEB)

Dey, N.C.; Mukhopadhyay, S. [Bengal Engineering College, Howrath (India). Dept. of Mining and Geology

1999-08-01

The analytical aspects of underground CPT (coal mine cost per tonne), which varies from mine to mine due to the different weightages of various contributing factors, are described. The CPT is not only dictated by the increasing wages but also by the availability of man-hour and accountability of machine utilization. An optimal blend of labour-intensive and machine-intensive methods involving least investment and operating cost, is a challenge for the coal industry. Technology upgradation and implementation, higher skill and morale, excellence in planning and monitoring, optimization in capacity utilization, and better consumer acceptability of coal will consistently improve the financial health of the coal mining sector. Other factors which will help improve the financial health of coal mining industries are (1) cost propaganda like safety week celebration; (2) cost consciousness at all levels; (3) noticeboard comprising the cost of man-hour and machine- hour; (4) no idle time for men as well as machine; (5) care to increase the life of machines; (6) scope of target amendment in a year; (7) prior to introducing costly machines, due weightage to be given on coal grade, mine life, geo-mining conditions; and (8) award to most economic mine and punishment to others rated below the BEP (break- even point). 2 refs., 3 figs.

Accelerated Rates of Nitrogen Cycling and N2O Production in Salt Marsh Sediments due to Long-Term Fertilization

Science.gov (United States)

Peng, X.; Ji, Q.; Angell, J.; Kearns, P.; Bowen, J. L.; Ward, B. B.

2014-12-01

Intensified sedimentary production of nitrous oxide (N2O), one of the most potent greenhouse gases, is one of the many possible environmental consequences of elevated nitrogen (N) loading into estuarine ecosystems. This study investigates the response to over 40 years of fertilization of nitrogen removal processes in the sediments of the Great Sippewissett Marsh in Falmouth, MA. Sediment slurries were incubated (1.5 hr) with trace amounts (fertilized sediments (0.89 nmol hr-1 g-1 wet weight) was 30-fold higher than in unfertilized sediments. The ratio of N2O to N2 production was also significantly higher in fertilized sediments (2.9%) than in unfertilized sediments (1.2%). This highlights the disproportionally large effect of long-term fertilization on N2O production in salt marsh sediments. The reduced oxygen level and higher ammonium concentrations in situ probably contributed to the significant rise in N2O production as a result of long-term fertilization. When detected, anammox and coupled nitrification-denitrification accounted for 10% and 14% of the total N2 production in fertilized sediments (30.5 nmol hr-1 g-1 wet weight), respectively, whereas neither was detected in unfertilized sediments. Thus these experiments indicate that N loading has important effects on multiple N cycle processes that result in N loss and N2O production.

Mercury pollution in sediments, benthic organisms and inshore fishes of Haifa Bay, Israel

Energy Technology Data Exchange (ETDEWEB)

Hornung, H; Krumgalz, B S; Cohen, Y

1984-01-01

Total mercury concentrations were determined in surficial sediments, eleven species of benthic organisms and six species of fish from Haifa Bay, Israel. The results show that essentially all of the shallow water zone of the Bay receives anthropogenic mercury. A mercury-cell chlor-alkali plant was identified as the source of pollution. Surficial sediments in vicinity of the plant, containing up to 0.99 micro-g Hg/g dry weight, were up to 157 times enriched in mercury relative to an unpolluted area. Mercury levels in the benthic organisms reflected the levels in the sediments. Maximal concentrations reaching 38.7 and 18.2 micro-g Hg/g dry weight were found in the carnivorous gastropod mollusks Arcularia circumcinta and Arcularia gibbosula, respectively. In all fish species, specimens caught in Haifa Bay had higher mercury concentrations in the muscle tissue than specimens caught south of the Bay. A maximal value of 1.66 micro-g Hg/g wet weight was recorded in Diplodus sargus. 17 references, 3 figures, 3 tables.

Reduction of angiocidin contributes to decreased HepG2 cell ...

African Journals Online (AJOL)

EB

2013-09-03

Sep 3, 2013 ... Tris, 5 mM EDTA pH7.5, 1% Triton X-100, and supplemented with 1mM PMSF). BCA Protein. Assay Reagent kit (Pierce) was used to determine the protein concentration. Equal amounts of protein. (10ug) were separated by SDS-PAGE and transferred to PVDF membranes. The membranes were blocked in ...

[Distribution of polycyclic aromatic hydrocarbons in water and sediment from Zhoushan coastal area, China].

Science.gov (United States)

Jiang, Min; Tuan, Le Huy; Mei, Wei-Ping; Ruan, Hui-Hui; Wu, Hao

2014-07-01

The spatial and temporal distribution of 16 polycyclic aromatic hydrocarbons (PAHs) has been investigated in water and sediments of Zhoushan coastal area every two months in 2012. The concentrations of total PAHs ranged from 382.3 to 816.9 ng x L(-1), with the mean value of 552.5 ng x L(-1) in water; whereas it ranged from 1017.9 to 3047.1 ng x g(-1), with the mean value of 2 022.4 ng x g(-1) in sediment. Spatial distribution showed that Yangshan and Yanwoshan offshore area had the maximum and minimum of total PAHs contents in water, while the maximum and minimum occurred at Yangshan and Zhujiajian Nansha offshore area in sediment. Temporal distribution revealed that total PAHs contents in water reached the maximum and minimum values in October and June, however in sediments these values were found in August and June, respectively. The PAHs pollution was affected by oil emission, charcoal and coal combustion. Using the biological threshold and exceeded coefficient method to assess the ecological risk of PAHs in Zhoushan coastal area, the result showed that sigma PAHs had a lower probability of potential risk, while there was a higher probability of potential risk for acenaphthylene monomer, and there might be ecological risk for acenaphthene and fluorene. Distribution of PAHs between sediment and water showed that Zhoushan coastal sediment enriched a lot of PAHs, meanwhile the enrichment coefficient (K(d) value) of sediment in Daishan island was larger than that in Zhoushan main island.

Planar algebra of the subgroup-subfactor

Indian Academy of Sciences (India)

We think of R α G as the II1-factor (R ∪{ug: g ∈ G}) ⊂ L(L2(R)), where ug(ˆx) ..... define a global trace on P, where for 0± the trace for P0± ∼= C is the obvious identity .... function for strings is either a local maximum or a local minimum. ..... In order to understand how the inclusion tangles act on the subgroup-subfactor planar.

Eighteen years experience of granulocyte donations-acceptable donor safety?

Science.gov (United States)

Axdorph Nygell, Ulla; Sollén-Nilsson, Agneta; Lundahl, Joachim

2015-10-01

Granulocyte transfusions are given to patients with life-threatening infections, refractory to treatment. The donors are stimulated with corticosteroids ± granulocyte colony stimulating factor (G-CSF). However, data regarding the donors' safety is sparse. The objective was therefore to evaluate short- and long-term adverse events (AE) in G-CSF stimulated donors. All consecutive granulocyte donors from 1994 to 2012 were identified through our registry. From the donation records, the number of aphereses, stimulation therapy, AE, blood values post donation, and recent status were evaluated. One hundred fifty-four volunteer donors were mobilized for 359 collections. Age at first granulocyte donation was 43 years (median; range 19-64 years). Follow-up was 60 months (median; range 0-229 months). The dose of G-CSF per collection was 3.8 ug/kg body weight (median; range 1.6-6.0 ug/kg). Sedimentation agent was HES. Short-term AE were mild. Blood values 4 weeks post donation with minor reductions/elevations mostly resolved in later donations. Fourteen donors were excluded from the registry due to hypertension (4), diabetes (2), atrial flutter (1), breast carcinoma (1), urethral carcinoma in situ (1), MGUS (1), thrombosis (1), anaphylaxis (1), primary biliary cirrhosis (1), and unknown (1). Three donors are deceased due to diabetes, acute myocardial infarction, and unknown cause. All excluded/deceased donors except one were excluded/died at least 6 months after first granulocyte donation. No serious short-term AE were observed. Due to the variability of diagnoses among excluded/deceased donors, we propose that it is less likely that granulocyte donations have a causative impact on these donors' exclusion or death. © 2014 Wiley Periodicals, Inc.

Dynamics of arsenic-containing compounds' sorption on sediments

Energy Technology Data Exchange (ETDEWEB)

Reczynski, W.; Posmyk, G.; Nowak, K. [AGH Univ. of Science and Technology, Faculty of Material Science and Ceramics, Dept. of Analytical Chemistry, Krakow (Poland)

2004-07-01

.015 {mu}g/ml). Less distinct sorption effects were noted at pH 7 and 9. Vistula river. At all pH values, a very significant decrease of inorganic As concentration up to 80% of the initial value, as well as a short time of achieving an equilibrium state (1 - 2.5 hours), was found. Dobczyce lake. Inorganic As was distinctly accumulated in sediments at pH 3 (decrease of As concentration in solution from 0.052 to 0.007 {mu}g/ml after 7.5 hours of the experiment) and at pH 5. At pH 7, about 40% of As was accumulated in sediments (solution As concentration decrease from 0.050 to 0.030). Only 20% of As adsorbed on sediments at pH 9. Very weak accumulation of organic form of As (DMAA) was found in all examined sediments at pH 3 and 5. At higher pH values no sorption was registered. (orig.)

Effects of sediment organic matter quality on bioaccumulation, degradation, and distribution of pyrene in two macrofaunal species and their surrounding sediment

DEFF Research Database (Denmark)

Granberg, Maria E.; Selck, Henriette

2007-01-01

Sediment dwelling macrofauna (infauna) are important vectors for the transfer of sediment-associated contaminants to higher trophic levels. Sedimenting organic matter constitutes an important food source for all benthic organisms and changes seasonally in terms of quantity and quality. Sediment...... imply that bioaccumulation and trophic transfer of sediment-associated PAH should increase following fresh organic matter input, e.g. after sedimentation of phytoplankton blooms. We stress the importance of considering behavioural characteristics of infauna and the trophic situation of the system when...

Speciation of phosphorus in the sediments of Lake Bini (Ngaoundere-Cameroon).

Science.gov (United States)

Sieliechi, Joseph Marie; Dangwang Dikdim, Jean-Marie; Noumi, Guy Bertrand

2014-08-01

In this study, spatial and seasonal variations of phosphorus fractions in Lake Bini sediments were evaluated using a sequential extraction method. The sampling of water and sediments (surface and coring) was carried out at seven sites around the lake during the dry season and the rainy season. The results showed that phosphorus is mainly in the inorganic form (L-P+Ca-P+Fe-P) in the sediments whatever the season may be. The rank order of phosphorus extracts obtained was Fe-P>Ca-P>OM-P>L-P>Res-P. The maximum values of phosphorus (sum of each fraction) were obtained in the rainy season at the sites D6 (298.12 +/- 12.37 microg P/g) and D4 (244.93 +/- 11.06 microg P/g) located beside water source 2 and farmland 2, respectively. The average values of the phosphorus content vary from 05.29 +/- 1.05 microg P/g to 102.58 +/- 4.62 microg P/g for the upper layer (0-5 cm depth); 04.67 +/- 0.66 microg P/g to 70.06 +/- 2.82 microg P/g for the medium layer (5-10 cm depth) and finally 04.63 +/- 0.98 microg P/g to 55.24 +/- 5.17 microg P/g for the deep layer (10-15 cm depth). The results of principal component analysis showed that processes which enhance Ca-P and Fe-P accumulation are probably related to the same factor and the origin of P depends on the source of pollution. The nature of the season plays a significant role in the geochemical composition of the sediments in phosphorus and on the eutrophication level of Lake Bini.

Tracking sedimentation from the historic A.D. 2011 Mississippi River flood in the deltaic wetlands of Louisiana, USA

Science.gov (United States)

Khan, Nicole S.; Horton, Benjamin P.; McKee, Karen L.; Jerolmack, Douglas; Falcini, Federico; Enache, Mihaela D.; Vane, Christopher H.

2013-01-01

Management and restoration of the Mississippi River deltaic plain (southern United States) and associated wetlands require a quantitative understanding of sediment delivery during large flood events, past and present. Here, we investigate the sedimentary fingerprint of the 2011 Mississippi River flood across the Louisiana coast (Atchafalaya Delta, Terrebonne, Barataria, and Mississippi River Delta basins) to assess spatial patterns of sedimentation and to identify key indicators of sediment provenance. The sediment deposited in wetlands during the 2011 flood was distinguished from earlier deposits based on biological characteristics, primarily absence of plant roots and increased presence of centric (planktonic) diatoms indicative of riverine origin. By comparison, the lithological (bulk density, organic matter content, and grain size) and chemical (stable carbon isotopes of bulk organic matter) properties of flood sediments were nearly identical to the underlying deposit. Flood sediment deposition was greatest in wetlands near the Atchafalaya and Mississippi Rivers and accounted for a substantial portion (37% to 85%) of the annual accretion measured at nearby monitoring stations. The amount of sediment delivered to those basins (1.1–1.6 g cm−2) was comparable to that reported previously for hurricane sedimentation along the Louisiana coast (0.8–2.1 g cm−2). Our findings not only provide insight into how large-scale river floods influence wetland sedimentation, they lay the groundwork for identifying previous flood events in the stratigraphic record.

Chlorinated polycyclic aromatic hydrocarbons in sediments from industrial areas in Japan and the United States.

Science.gov (United States)

Horii, Yuichi; Ohura, Takeshi; Yamashita, Nobuyoshi; Kannan, Kurunthachalam

2009-11-01

Chlorinated polycyclic aromatic hydrocarbons (ClPAHs) are widespread environmental pollutants in the urban environment. Nevertheless, there is little information available regarding the occurrence and profiles of ClPAHs in environmental matrices. In this study, residual concentrations and profiles of 20 individual ClPAHs and 16 US EPA-priority PAHs were determined using high- resolution gas chromatography-high-resolution mass spectrometry in sediments from water bodies near industrialized areas: Tokyo Bay, Japan; the Saginaw River watershed, Michigan, USA; a former chlor-alkali plant, Georgia, USA; and the New Bedford Harbor Superfund site, Massachusetts, USA. A sediment core from Tokyo Bay showed temporal patterns in the distribution of ClPAHs from the 1950s through 2004. The fluxes of ClPAHs and 16 priority PAHs in Tokyo Bay sediment core were 0.029-0.57 ng/cm(2)/year and 85-609 ng/cm(2)/year, respectively; fluxes were lowest in the 1950s and highest in 1989-1990. In the United States, a high mean concentration of ClPAHs was found in sediment collected near a former chlor-alkali plant [8820 pg/g dry weight (dry wt)], and lower mean concentrations were found for New Bedford Harbor (1880 pg/g dry wt) and the Saginaw River watershed (1140 pg/g dry wt). Among individual ClPAHs, 6-ClBaP and 1-ClPyr were the dominant compounds in sediments; this pattern is similar to the pattern reported in the literature for waste incineration and ambient urban air samples. Significant correlation between SigmaClPAH concentrations and Sigmaparent-PAH concentrations in Tokyo Bay sediment implies that the sources and distribution of ClPAHs are directly related to those of parent PAHs. We also analyzed ClPAHs and parent PAHs in blue mussels from New Bedford Harbor. The mean concentration of ClPAHs in mussels from New Bedford Harbor was 21 ng/g lipid weight, a concentration three orders of magnitude lower than the mean concentration of parent PAHs. Low-molecular-weight ClPAHs predominated

Oil spill in the Rio de la Plata estuary, Argentina: 2-hydrocarbon disappearance rates in sediments and soils

International Nuclear Information System (INIS)

Colombo, J.C.; Barreda, A.; Bilos, C.; Cappelletti, N.; Migoya, M.C.; Skorupka, C.

2005-01-01

The 6-month assessment of the oil spill impact in the Rio de la Plata described in the preceding paper [Colombo, J.C., Barreda, A., Bilos, C., Cappelletti, N., Demichelis, S., Lombardi, P., Migoya, M.C., Skorupka, C., Suarez, G., 2004. Oil spill in the Rio de la Plata estuary, Argentina: 1 - biogeochemical assessment of waters, sediments, soils and biota. Environmental Pollution] was followed by a 13- and 42-month campaigns to evaluate the progress of hydrocarbon decay. Average sediment hydrocarbon concentrations in each sampling include high variability (85-260%) due to contrasting site conditions, but reflect a significant overall decrease after 3 years of the spill: 17 ± 27, 18 ± 39 to 0.54 ± 1.4 μg g -1 for aliphatics; 0.44 ± 0.49, 0.99 ± 1.6 to 0.04 ± 0.03 μg g -1 for aromatics at 6, 13 and 42 months, respectively. Average soil hydrocarbon levels are 100-1000 times higher and less variable (61-169%) than sediment values, but display a clear attenuation: 3678 ± 2369, 1880 ± 1141 to 6.0 ± 10 μg g -1 for aliphatics and 38 ± 26, 49 ± 32 to 0.06 ± 0.04 μg g -1 for aromatics. Hydrocarbon concentrations modeled to first-order rate equations yield average rate constants of total loss (biotic + abiotic) twice as higher in soils (k = 0.18-0.19 month -1 ) relative to sediments (0.08-0.10 month -1 ). Individual aliphatic rate constants decrease with increasing molecular weight from 0.21 ± 0.07 month -1 for isoprenoids and -1 for >n-C27, similar to hopanes (0.10 ± 0.05 month -1 ). Aromatics disappearance rates were more homogeneous with higher values for methylated relative to unsubstituted species (0.17 ± 0.05 vs. 0.12 ± 0.05 months -1 ). Continued hydrocarbon inputs, either from biogenic (algal n-C15,17; vascular plant n-C27,29) or combustion related sources (fluoranthene and pyrene), appear to contribute to reduced disappearance rate. According to the different loss rates, hydrocarbons showed clear compositional changes from 6-13 to 42 months

Modeling subglacial sediment discharge in 1-dimension: comparison with measurments and implications for glacial retreat

Science.gov (United States)

Delaney, I. A.; Werder, M.; Farinotti, D.

2017-12-01

In recent decades increased sedimentation rates have been observed in reservoirs downstream of some retreating glaciers. This material either originates from slopes recently exposed by glacier retreat and no longer stabilized by ice, or subglacially, where pressurized melt water transports sediments from the glacier bed. Some evidence suggests that recently exposed periglacial areas can stablize relatively quickly and in some catchments provides a smaller precentage of the total sediment compared to the subglacial environment. As a result, in order predict and forecast sediment yield from glaciated catchments as glaciers thin and thier hydrology evolves, a subglacial sediment transport model must be implemented. Here a simple 1-dimensional glacio-hydraulic model uses the Darcy-Weissbach relationship to determine shear-stress of presurized water on the glacier bed. This is coupled with a sediment transport relationship to determine quantity of discharged material from the glacier snout. Several tuning factors allow calibration and the model to reproduces processes known to occur subglacially, including seasonal evolution of sediment expulsion and deposition of sediment on adverse slopes of overdeepenings. To asses the model's application to real glaciers, sediment flux data has been collected from Gornergletscher, Aletschgletscher and Griesgletscher in the Swiss Alps over time-scales of up to decades. By calibrating to these data, the skill of the model in recreating sediment trends and volumes is assesed. The outputs capture annual erosion quanities relatively well, however, challenges exist in capturing inter-annual variations in sediment discharge. Many of the model's short comings relate to caputuring the spatial distribution of sediment throughout the glacier bed, which is particularing difficult in 1-dimension. However, this work suggests that a simple models can be used to predict subglacial sediment transport with reasonable ability. Additionally, further

Unigene BLAST: CBRC-DMEL-03-0012 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-DMEL-03-0012 gnl|UG|Dm#S40593121 DMG1C.2_1.G07.C1 MODENCODE_DM_A Drosophila melanogaster cDNA clone DMG...1-chr3R.3.082.a, mRNA sequence /clone=DMG1-chr3R.3.082.a /gb=EW713160 /gi=156142114 /ug=Dm.27906 /len=1533 0.64 34% ...

Unigene BLAST: CBRC-DMEL-08-0015 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-DMEL-08-0015 gnl|UG|Dm#S40593121 DMG1C.2_1.G07.C1 MODENCODE_DM_A Drosophila melanogaster cDNA clone DMG...1-chr3R.3.082.a, mRNA sequence /clone=DMG1-chr3R.3.082.a /gb=EW713160 /gi=156142114 /ug=Dm.27906 /len=1533 4e-07 35% ...

Unigene BLAST: CBRC-DMEL-08-0038 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-DMEL-08-0038 gnl|UG|Dm#S40593121 DMG1C.2_1.G07.C1 MODENCODE_DM_A Drosophila melanogaster cDNA clone DMG...1-chr3R.3.082.a, mRNA sequence /clone=DMG1-chr3R.3.082.a /gb=EW713160 /gi=156142114 /ug=Dm.27906 /len=1533 6e-10 32% ...

Unigene BLAST: CBRC-DMEL-08-0039 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-DMEL-08-0039 gnl|UG|Dm#S40593121 DMG1C.2_1.G07.C1 MODENCODE_DM_A Drosophila melanogaster cDNA clone DMG...1-chr3R.3.082.a, mRNA sequence /clone=DMG1-chr3R.3.082.a /gb=EW713160 /gi=156142114 /ug=Dm.27906 /len=1533 4e-07 39% ...

Unigene BLAST: CBRC-DMEL-03-0071 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-DMEL-03-0071 gnl|UG|Dm#S40593121 DMG1C.2_1.G07.C1 MODENCODE_DM_A Drosophila melanogaster cDNA clone DMG...1-chr3R.3.082.a, mRNA sequence /clone=DMG1-chr3R.3.082.a /gb=EW713160 /gi=156142114 /ug=Dm.27906 /len=1533 3e-07 47% ...

Unigene BLAST: CBRC-DMEL-08-0057 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-DMEL-08-0057 gnl|UG|Dm#S40593121 DMG1C.2_1.G07.C1 MODENCODE_DM_A Drosophila melanogaster cDNA clone DMG...1-chr3R.3.082.a, mRNA sequence /clone=DMG1-chr3R.3.082.a /gb=EW713160 /gi=156142114 /ug=Dm.27906 /len=1533 2e-06 22% ...

Differential response of oyster shell powder on enzyme profile and nutritional value of oyster mushroom Pleurotus florida PF05.

Science.gov (United States)

Naraian, Ram; Narayan, Om Prakash; Srivastava, Jatin

2014-01-01

Oyster mushroom Pleurotus florida was cultivated on different combinations of wheat straw (WS) as basal substrate and oyster shell powder (OSP) supplement. The OSP supplementation considerably responded to different cultivation phases. The mycelium grew fast and showed rapid growth rate (8.91 mmd(-1)) in WS + OSP (97 + 3) combination while WS + OSP (92 + 8) showed maximum laccase (3.133 U/g) and Mn peroxidase (MnP) activities (0.091 U/g). The climax level of laccase (5.433 U/g) and MnP (0.097 U/g) was recorded during fruit body initiation in WS + OSP (97 + 3) and WS + OSP (98 + 2) combinations, respectively. The WS + OSP (97 + 3) combination represented the best condition for mushroom cultivation and produced the highest biological efficiency (147%). In addition, protein and lipid contents in fruit bodies were slightly improved in response to OSP. The carbohydrate was significantly increased by raising concentration of OSP. The highest values of protein, carbohydrate, and lipid noted were 31.3 μg/g, 0.0639 (g/g), and 0.373 (g/g) correspondingly. Conclusively it was evident that lower concentrations of OSP acted positively and relatively to higher concentrations and improved nutritional content which may suitably be used to enhance both yield and nutritional values of mushroom.

Influence of tubificid worms on nutrient fluxes across water-sediment interface in fish farm settling ponds

Directory of Open Access Journals (Sweden)

Puigagut J.

2014-04-01

Full Text Available The influence of tubificid worms on nutrient translocation from water to fish farm sediments accumulating in settling ponds was addressed under laboratory conditions. Small microcosms of 0.5 L were filled up with 35 g of sludge from a fish farm settling pond and 0.15 L of filtered settling pond water. The experimental set up consisted of one control line (no worms added, a second experimental line with 1 mg of tubificid worms·g-1 fresh sediment (550 individuals·m-2 and a third experimental line with 40 mg of tubificid worms·g-1 fresh sediment (22 000 individuals·m-2. Nutrients translocation was determined by monitoring overlaying water concentration of ammonia, nitrate and phosphate for ten days. Results showed that abundances of 550 individuals·m-2 had no significant influence on the fluxes of nutrients here considered. However, the influence of higher abundances of tubificids (22 000 individuals·m-2 was of significant extent on the translocation of nitrate and phosphate. Accordingly, bioturbation of tubificids caused 55% lower nitrate uptake by the sediment when compared to control conditions. Phosphorus released by the sediments of the control condition was ca. 90% higher than that recorded under abundances of tubificids (22 000 individuals·m-2. Results obtained allowed us to estimate that fish farm settling ponds highly colonized by tubificid worms (22 000 individuals·m-2 may contribute to decrease phosphorus discharge (in terms of soluble phosphorus in ca. 5 g of P·ton-1 of fish produced.

Congener-specific distribution and bioaccumulation of short-chain chlorinated paraffins in sediments and bivalves of the Bohai Sea, China.

Science.gov (United States)

Ma, Xindong; Chen, Chen; Zhang, Haijun; Gao, Yuan; Wang, Zhen; Yao, Ziwei; Chen, Jiping; Chen, Jingwen

2014-02-15

Short-chain chlorinated paraffins (SCCPs) are a new type of persistent organic pollutants that are of great environmental concern because of their wide distribution. In this study, surface sediments and bivalve samples were collected from the coastal area of the Bohai Sea in China. Total SCCP (ΣSCCP) concentrations in surface sediments and bivalves ranged from 97.4 ng g(-1) dry weight (dw) to 1756.7 ng g(-1) dw and 476.4-3269.5 ng g(-1) dw, respectively. C10-CPs and C11-CPs were the predominant homologue groups in all sediments and bivalves. Specific congener composition analysis and correspondence analysis indicated that the local SCCP source mainly came from CP-42 and CP-52 products, and riverine input had an important function. The biota-sediment accumulation factors of ΣSCCPs for bivalves ranged from 1.08 to 1.61, and a significant correlation indicated that the SCCP congener with higher chlorination degree was more likely to be accumulated in bivalves. Copyright © 2014. Published by Elsevier Ltd.

Geochemistry records from laminated sediments of Shira Lake (Russian Asia)

Science.gov (United States)

Phedorin, M.; Vologina, E.; Drebuschak, M.; Tolomeev, A.; Kirichenko, I.; Toyabin, A.

2009-04-01

We measured downcore elements distributions in five cores collected across the Shira Lake situated in Central part of Asia (E90o12', N54o30'). The lake is small (32km2), saline (ca.20g/l SO4-, Cl-, Na+, Mg+, K+), being filled with regional precipitation of about 300mm/year (mainly through one major tributary, river Son) and has no surface outflow. The aim of our study was to reconstruct history of changes in the regime of the lake that happened both before and during period of instrumental meteorological observations. In particular, we were interested in lake-level changes due to evaporation, water supply from surface and from underground sources, and in changes of bioproduction in the lake as well. To construct depth-age model for the cores, we measured Cs-137 and unsupported Pb-210 in top layers of the cores. The sedimentation rate thus identified varied in the range of 1-2 mm/year for different cores. We visually observed fine sedimentation ‘rhythms' having thickness of about 0.x-2.x mm: these layers may now be reliably identified as annual lamination. We also determined concentrations of elements in the sediments by recording x-ray fluorescence (XRF) spectra when continuously scanning the halves of the cores under sharp synchrotron radiation (SR) beam, using an instrument described in (Zolotarev et al., 2001). The resolution of the scanning was 0.1 mm. After processing of the measured XRF-SR data as in (Phedorin and Goldberg, 2005) we obtained downcore records of 20 elements. We correlated all five cores employing elements patterns. We qualitatively identified variations in surface-water supply treating markers of ‘clastic' material (Ti, Rb, Zr). We identified downcore variations in authgenic mineralization, which appeared to have different kinds: Ca-related, Sr-related, Ba-related, Fe-related. We tried to assess biogenic production changes from Br distribution, admitting analogy of Br in Shira sediments to Br in Lake Baikal sediments (Phedorin et al., 2000

Bioleaching of heavy metal polluted sediment: influence of temperature and oxygen. Pt. 1

Energy Technology Data Exchange (ETDEWEB)

Loeser, C. [Technische Universitaet Dresden, Institut fuer Lebensmittel- und Bioverfahrenstechnik, Bergstrasse 120, 01062 Dresden (Germany); Zehnsdorf, A. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Umwelt- und Biotechnologisches Zentrum, Permoserstrasse 15, 04318 Leipzig (Germany); Goersch, K.; Seidel, H. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Department Bioremediation, Permoserstrasse 15, 04318 Leipzig (Germany)

2006-08-15

half-saturation constant of about 0.01 mg/L. Stoichiometric coefficients describing the relationship between the mass of S{sup 0}, O{sub 2} and CO{sub 2} consumed are scarcely available. The growth of S{sup 0}-oxidizing, obligate aerobic, autotrophic bacteria was, therefore, stoichiometrically balanced (by using a yield coefficient of Y{sub X/S} = 0.146 g cells/g S{sup 0}, calculated with data from the literature): 24.14 S{sup 0} + 29.21 O{sub 2} + 27.14 H{sub 2}O + 5 CO{sub 2} + NO{sub 3}{sup -}{yields} C{sub 5}H{sub 7}O{sub 2}N + 24.14 SO{sub 4}{sup 2-} + 47.28 H{sup +}, which resulted in Y{sub O{sub 2}}{sub /S} = 1.21 g O{sub 2}/g S{sup 0} and Y{sub CO{sub 2}}{sub /S} = 0.28 g CO{sub 2}/g S{sup 0}. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

Geology of the U12n.07 UG-3 drill hole, area 12, Nevada Test Site

International Nuclear Information System (INIS)

Terry, S.S.; Cunningham, M.J.

1975-11-01

The U12n.07 UG-3 horizontal drill hole, located near the eastern edge of the center of Rainier Mesa, Nevada Test Site, was drilled to a total depth of 809 m (2,653 ft). This hole was drilled to further evaluate the tunnel-level stratigraph, and structure southwest of the U12n tunnel complex. The drill hole is collared in the middle of Tertiary tunnel bed 3A and penetrates upsection through tunnel beds 3 and 4 and terminates in subunit 4K, all of Tertiary age. Stratigraphy, structure, engineering geology, and physical properties and their relation to tunnel engineering are discussed

4G/5G polymorphism modulates PAI-1 circulating levels in obese women.

Science.gov (United States)

Fernandes, Karla S; Sandrim, Valéria C

2012-05-01

The increase in plasminogen activator inhibitor type 1 (PAI-1) has been described as a risk factor to thrombosis-related diseases. In addition, it has been demonstrated that the variant 4G of polymorphism 4G/5G located in promoter region of PAI-1 gene is associated with higher PAI-1 levels. We investigate the role of this polymorphism on circulating PAI-1 concentration in a population of 57 obese women (23%, 4G/4G; 49%, 4G/5G and 28%, 5G/5G genotypes). Our results demonstrate a genotype-specific modulation on PAI-1 levels in obese women, thus 5G/5G genotype presented significantly lower levels of plasma PAI-1 when compared to 4G/4G group (46 ± 19 ng/mL vs. 63 ± 13 ng/mL, respectively). Our findings indicate that obese carriers of 4G/4G genotype may have increased risk to develop thrombotic diseases.

Metal concentrations of river water and sediments in West Java, Indonesia.

Science.gov (United States)

Yasuda, Masaomi; Yustiawati; Syawal, M Suhaemi; Sikder, Md Tajuddin; Hosokawa, Toshiyuki; Saito, Takeshi; Tanaka, Shunitz; Kurasaki, Masaaki

2011-12-01

To determine the water environment and pollutants in West Java, the contents of metals and general water quality of the Ciliwung River in the Jakarta area were measured. High Escherichia coli number (116-149/mL) was detected downstream in the Ciliwung River. In addition to evaluate mercury pollution caused by gold mining, mercury contents of water and sediment samples from the Cikaniki River, and from paddy samples were determined. The water was not badly polluted. However, toxic metals such as mercury were detected at levels close to the baseline environmental standard of Indonesia (0.83-1.07 μg/g of sediments in the Cikaniki River). From analyses of the paddy samples (0.08 μg/g), it is considered that there is a health risk caused by mercury.

Lithogenic fluxes to the deep Arabian Sea measurEd. by sediment traps

Digital Repository Service at National Institute of Oceanography (India)

Ramaswamy, V.; Nair, R.R; Manganini, S.J.; Haake, B.; Ittekkot, V.

. 38. No. 2. pp 1~g-\\[~44 It,lqt. fllC~g...4)i49tql $31~) 4- 0.till Pnnted m Great Britain. ~ lg~t Pergamon Press pie Lithogenic fluxes to the deep Arabian Sea measured by sediment traps V. RAMASWAMY,* R. R. NAIR,* S. MANGANINI,# B. HAAKE~. and V... (MIct, lrdAN et al., 1984). Most of the present suspended sediment discharge is in July and August, during the peak of the southwest monsoon period, with negligible discharge during other times (I'rrEKKO'r and ARAIN, 1986). The Narmada and Tapti...

Geomicrobiology of High Level Nuclear Waste-Contaminated Vadose Sediments at the Hanford Site, Washington State

International Nuclear Information System (INIS)

Fredrickson, Jim K.; Zachara, John M.; Balkwill, David L.; Kennedy, David W.; Li, Shu-Mei W.; Kostandarithes, Heather M.; Daly, Michael J.; Romine, Margaret F.; Brockman, Fred J.

2004-01-01

Sediments from a high-level nuclear waste plume were collected as part of investigations to evaluate the potential fate and migration of contaminants in the subsurface. The plume originated from a leak that occurred in 1962 from a waste tank consisting of high concentrations of alkali, nitrate, aluminate, Cr(VI), 137Cs, and 99Tc. Investigations were initiated to determine the distribution of viable microorganisms in the vadose sediment samples, probe the phylogeny of cultivated and uncultivated members, and evaluate the ability of the cultivated organisms to survive acute doses of ionizing radiation. The populations of viable aerobic heterotrophic bacteria were generally low, from below detection to ∼104 7 CFU g-1 but viable microorganisms were recovered from 11 of 16 samples including several of the most radioactive ones (e.g., > 10 ?Ci/g 137Cs). The isolates from the contaminated sediments and clone libraries from sediment DNA extracts were dominated by members related to known Gram-positive bacteria. Gram-positive bacteria most closely related to Arthrobacter species were the most common isolates among all samples but other high G+C phyla were also represented including Rhodococcus and Nocardia. Two isolates from the second most radioactive sample (>20 ?Ci 137Cs g-1) were closely related to Deinococcus radiodurans and were able to survive acute doses of ionizing radiation approaching 20kGy. Many of the Gram-positive isolates were resistant to lower levels of gamma radiation. These results demonstrate that Gram-positive bacteria, predominantly high G+C phyla, are indigenous to Hanford vadose sediments and some are effective at surviving the extreme physical and chemical stress associated with radioactive waste

Comparison of GC-ICP-MS and HPLC-ICP-MS for species-specific isotope dilution analysis of tributyltin in sediment after accelerated solvent extraction

International Nuclear Information System (INIS)

Wahlen, Raimund; Wolff-Briche, Celine

2003-01-01

This study describes a direct comparison of GC and HPLC hyphenated to ICP-MS determination of tributyltin (TBT) in sediment by species-specific isotope dilution analysis (SS-IDMS). The certified reference sediment PACS-2 (NRC, Canada) and a candidate reference sediment (P-18/HIPA-1) were extracted using an accelerated solvent extraction (ASE) procedure. For comparison of GC and LC methods an older bottle of PACS-2 was used, whilst a fresh bottle was taken for demonstration of the accuracy of the methods. The data obtained show good agreement between both methods for both the PACS-2 sediment (LC-ICP-IDMS 828±87 ng g -1 TBT as Sn, GC-ICP-IDMS 848±39 ng g -1 TBT as Sn) and the P-18/ HIPA-1 sediment (LC-ICP-IDMS 78.0±9.7 ng g -1 TBT as Sn, GC-ICP-IDMS 79.2±3.8 ng g -1 TBT as Sn). The analysis by GC-ICP-IDMS offers a greater signal-to-noise ratio and hence a superior detection limit of 0.03 pg TBT as Sn, in the sediment extracts compared to HPLC-ICP-IDMS (3 pg TBT as Sn). A comparison of the uncertainties associated with both methods indicates superior precision of the GC approach. This is related to the better reproducibility of the peak integration, which affects the isotope ratio measurements used for IDMS. The accuracy of the ASE method combined with HPLC-ICP-IDMS was demonstrated during the international interlaboratory comparison P-18 organised by the Comite Consultatif pour la Quantite de Matiere (CCQM). The results obtained by GC-ICP-IDMS for a newly opened bottle of PACS-2 were 1087±77 ng g -1 Sn for DBT and 876±51 ng g -1 Sn for TBT (expanded uncertainties with a coverage factor of 2), which are in good agreement with the certified values of 1090±150 ng g -1 Sn and 980±130 ng g -1 Sn, respectively. (orig.)

Children’s residential exposure to selected allergens and microbial indicators: endotoxins and (1→3-β-D-glucans

Directory of Open Access Journals (Sweden)

Anna Kozajda

2013-12-01

Full Text Available Objectives: The study was aimed at assessment of exposure to endotoxins, (1→3-β-D-glucans and mite, cockroach, cat, dog allergens present in settled dust in premises of children as agents which may be significantly correlated with the occurrence of allergic symptoms and diseases in children. Materials and Methods: The study covered 50 homes of one- or two-year-old children in Poland. Samples of settled dust were taken from the floor and the child's bed. The levels of (1→3-β-D-glucans (floor, endotoxins (floor and allergens of mite, cat, dog and cockroach (floor and bed were analyzed. Results: Average geometric concentrations (geometric standard deviation of endotoxins, (1→3-β-D-glucans, Der p1, Fel d1, Can f1 and Bla g1 in children homes were on the floor 42 166.0 EU/g (3.2, 20 478.4 ng/g (2.38, 93.9 ng/g (6.58, 119.8 ng/g (13.0, 288.9 ng/g (3.4, 0.72 U/g (4.4 and in their beds (only allergens 597.8 ng/g (14.2, 54.1 ng/g (4.4, 158.6 ng/g (3.1 0.6 U/g (2.9, respectively. When the floor was covered with the carpet, higher concentrations of endotoxins, (1→3-β-D-glucans and allergens (each type were found in the settled dust (p < 0.05. The trend was opposite in case of allergens (except dog analyzed from bed dust and significantly higher concentrations were found in the rooms with smooth floor (p < 0.05. Conclusions: Among the analyzed factors only the type of floor significantly modified both the level of biological indicators and allergens. The results of this study could be the base for verifying a hypothesis that carpeting may have a protective role against high levels of cockroach, dog and cat allergens.

[Correlation and interconversion between erythrocyte cholinesterase values obtained by the Michel and the EQM techniques].

Science.gov (United States)

Carmona-Fonseca, Jaime

2006-12-01

Several techniques are available to measure red cell cholinesterase; therefore, evaluations with several methods provide a measure of concordance. An equation was formulated to transform native data of reference values to reference units of cholinesterase activity as measured by Michel and EQM tests. The experimental design was descriptive, transversal and prospective. The group sampled was a representative adult working population, aged 18-75, without previous exposure to cholinesterase inhibitors pesticides. The individuals were affiliated to the Social Security System and resided in Valle de Aburrá and Cercano Oriente Antioqueño (Antioquia Province, northwestern Colombia). Of 827 individuals, quantitative erythrocytes (Michel y EQM) tests exhibited "r" coefficients between 0.67 and R2 coefficient of 44%.,This indicated that one test explained the results in other test in 44% of the cases. The corelation was higher in Aburrá than in Oriente. The linear model for the 827 individuals was as follows: EQM U/g oxy-hemoglobin = 9.575 U/ g oxy-hemoglobin + 29.791 (Michel delta pH/hour). Michel delta pH/hr = 0.3312 delta pH/hour + 0.0149 (EQM U/g oxy-hemoglobin), where EQM was expressed in U/g oxy-hemoglobin and Michel pH change/hr. Inter-sections (coefficient a) and inclines (coefficient b) were significant in this model. In the adjusted equations, after exclusion of 12 extreme data (1.5% of 827), the r coefficient increased from 0.67 to 0.72 The adjusted equations were as follows: EQM U/g oxy-hemoglobin = 8.1884 U/g oxy-hemoglobin + 31.3920 (Michel delta pH/hour); Michel delta pH/hr = 0.2925 delta pH/hr + 0.0161 (EQM U/g oxy-hemoglobin). This system of linear equations permitted the transformation of Michel (delta PH/ hr) units to EQM (U/g oxy-hemoglobin) units and vice versa. This will facilitate data comparisons by clinicians and epidemiologists who are using these methods of cholinesterase measurement.

Cytokinetically quiescent (G0/G1) human multiple myeloma cells are susceptible to simultaneous inhibition of Chk1 and MEK1/2.

Science.gov (United States)

Pei, Xin-Yan; Dai, Yun; Youssefian, Leena E; Chen, Shuang; Bodie, Wesley W; Takabatake, Yukie; Felthousen, Jessica; Almenara, Jorge A; Kramer, Lora B; Dent, Paul; Grant, Steven

2011-11-10

Effects of Chk1 and MEK1/2 inhibition were investigated in cytokinetically quiescent multiple myeloma (MM) and primary CD138(+) cells. Coexposure to the Chk1 and MEK1/2 inhibitors AZD7762 and selumetinib (AZD6244) robustly induced apoptosis in various MM cells and CD138(+) primary samples, but spared normal CD138(-) and CD34(+) cells. Furthermore, Chk1/MEK1/2 inhibitor treatment of asynchronized cells induced G(0)/G(1) arrest and increased apoptosis in all cell-cycle phases, including G(0)/G(1). To determine whether this regimen is active against quiescent G(0)/G(1) MM cells, cells were cultured in low-serum medium to enrich the G(0)/G(1) population. G(0)/G(1)-enriched cells exhibited diminished sensitivity to conventional agents (eg, Taxol and VP-16) but significantly increased susceptibility to Chk1 ± MEK1/2 inhibitors or Chk1 shRNA knock-down. These events were associated with increased γH2A.X expression/foci formation and Bim up-regulation, whereas Bim shRNA knock-down markedly attenuated lethality. Immunofluorescent analysis of G(0)/G(1)-enriched or primary MM cells demonstrated colocalization of activated caspase-3 and the quiescent (G(0)) marker statin, a nuclear envelope protein. Finally, Chk1/MEK1/2 inhibition increased cell death in the Hoechst-positive (Hst(+)), low pyronin Y (PY)-staining (2N Hst(+)/PY(-)) G(0) population and in sorted small side-population (SSP) MM cells. These findings provide evidence that cytokinetically quiescent MM cells are highly susceptible to simultaneous Chk1 and MEK1/2 inhibition.

Error-free versus mutagenic processing of genomic uracil--relevance to cancer.

Science.gov (United States)

Krokan, Hans E; Sætrom, Pål; Aas, Per Arne; Pettersen, Henrik Sahlin; Kavli, Bodil; Slupphaug, Geir

2014-07-01

Genomic uracil is normally processed essentially error-free by base excision repair (BER), with mismatch repair (MMR) as an apparent backup for U:G mismatches. Nuclear uracil-DNA glycosylase UNG2 is the major enzyme initiating BER of uracil of U:A pairs as well as U:G mismatches. Deficiency in UNG2 results in several-fold increases in genomic uracil in mammalian cells. Thus, the alternative uracil-removing glycosylases, SMUG1, TDG and MBD4 cannot efficiently complement UNG2-deficiency. A major function of SMUG1 is probably to remove 5-hydroxymethyluracil from DNA with general back-up for UNG2 as a minor function. TDG and MBD4 remove deamination products U or T mismatched to G in CpG/mCpG contexts, but may have equally or more important functions in development, epigenetics and gene regulation. Genomic uracil was previously thought to arise only from spontaneous cytosine deamination and incorporation of dUMP, generating U:G mismatches and U:A pairs, respectively. However, the identification of activation-induced cytidine deaminase (AID) and other APOBEC family members as DNA-cytosine deaminases has spurred renewed interest in the processing of genomic uracil. Importantly, AID triggers the adaptive immune response involving error-prone processing of U:G mismatches, but also contributes to B-cell lymphomagenesis. Furthermore, mutational signatures in a substantial fraction of other human cancers are consistent with APOBEC-induced mutagenesis, with U:G mismatches as prime suspects. Mutations can be caused by replicative polymerases copying uracil in U:G mismatches, or by translesion polymerases that insert incorrect bases opposite abasic sites after uracil-removal. In addition, kataegis, localized hypermutations in one strand in the vicinity of genomic rearrangements, requires APOBEC protein, UNG2 and translesion polymerase REV1. What mechanisms govern error-free versus error prone processing of uracil in DNA remains unclear. In conclusion, genomic uracil is an

Plasminogen Activator Inhibitor-1 (PAI-1) gene 4G/5G alleles frequency distribution in the Lebanese population.

Science.gov (United States)

Shammaa, Dina M R; Sabbagh, Amira S; Taher, Ali T; Zaatari, Ghazi S; Mahfouz, Rami A R

2008-09-01

Plasminogen activator inhibitor-1 (PAI-1) is an inhibitor of fibrinolysis. Increased plasma PAI-1 levels play an essential role in the pathogenesis of cardiovascular risk and other diseases associated with thrombosis. The 4G/5G polymorphism of the PAI-1 promoter region has been extensively studied in different populations. We studied 160 healthy unrelated Lebanese individuals using a reverse hybridization PCR assay to detect the 5G/5G, 4G/5G and, 4G/4G genotypes of the PAI-1 gene and the frequencies of the 4G and 5G alleles. We found that 4G/5G genotype was the most prevalent (45.6%) followed by 5G/5G (36.9%) and 4G/4G (17.5%). The frequencies of the 4G and 5G alleles were calculated to be 0.403 and 0.597, respectively. Compared to other ethnic communities, the Lebanese population was found to harbour a relatively high prevalence of the rare 4G allele. This, in turn, may predispose this population to develop cardiovascular diseases and other thrombotic clinical conditions. This study aids to enhance our understanding of the genetic features of the Lebanese population.

Sediment Transport Over Run-of-River Dams

Science.gov (United States)

O'Brien, M.; Magilligan, F. J.; Renshaw, C. E.

2016-12-01

Dams have numerous documented effects that can degrade river habitat downstream. One significant effect of large dams is their ability to trap sediment delivered from upstream. This trapping can alter sediment transport and grain size downstream - effects that often motivate dam removal decisions. However, recent indirect observations and modeling studies indicate that small, run-of-river (ROR) dams, which do not impede discharge, may actually leak sediment downstream. However, there are no direct measurements of sediment flux over ROR dams. This study investigates flow and sediment transport over four to six different New England ROR dams over a summer-fall field season. Sediment flux was measured using turbidity meters and tracer (RFID) cobbles. Sediment transport was also monitored through an undammed control site and through a river where two ROR dams were recently removed. These data were used to predict the conditions that contribute to sediment transport and trapping. Year 1 data show that tracer rocks of up to 61 mm were transported over a 3 m ROR dam in peak flows of 84% of bankfull stage. These tracer rocks were transported over and 10 m beyond the dam and continue to move downstream. During the same event, comparable suspended sediment fluxes of up to 81 g/s were recorded both upstream and downstream of the dam at near-synchronous timestamps. These results demonstrate the potential for sediment transport through dammed rivers, even in discharge events that do not exceed bankfull. This research elucidates the effects of ROR dams and the controls on sediment transport and trapping, contributions that may aid in dam management decisions.

Sediment quality and ecorisk assessment factors for a major river system

International Nuclear Information System (INIS)

Johnson, V.G.; Wagner, J.J.; Cutshall, N.H.

1993-08-01

Sediment-related water quality and risk assessment parameters for the Columbia River were developed using heavy metal loading and concentration data from Lake Roosevelt (river km 1120) to the mouth and adjacent coastal zone. Correlation of Pb, Zn, Hg, and Cd concentrations in downstream sediments with refinery operations in British Columbia suggest that solutes with K d 's > 10 5 reach about 1 to 5 μg/g per metric ton/year of input. A low-suspended load (upriver avg. <10 mg/L) and high particle-surface reactivity account for the high clay-fraction contaminant concentrations. In addition, a sediment exposure path was demonstrated based on analysis of post-shutdown biodynamics of a heavy metal radiotracer. The slow decline in sediment was attributed to resuspension, bioturbation, and anthropogenic disturbances. The above findings suggest that conservative sediment quality criteria should be used to restrict additional contaminant loading in the upper drainage basin. The issuance of an advisory for Lake Roosevelt, due in part to Hg accumulation in large sport fish, suggests more restrictive controls are needed. A monitoring strategy for assessing human exposure potential and the ecological health of the river is proposed

Perswazyjność komunikatów reklamowych w Internecie na podstawie analizy usług finansowych SKOK-ów

OpenAIRE

Idzik, Beata

2014-01-01

Praca jest wynikiem kilkuletnich obserwacji praktycznej strony funkcjonowania reklamy w zakresie usług finansowych. Autorka starała się oddać wyraz swojemu zainteresowaniu psychologią konsumenta, marketingiem w sektorze finansowym a także fascynacji możliwościom, jakie stwarzają w tym zakresie nowe technologie oparte na Internecie. Praca ma charakter teoretyczno - badawczy. W założeniach metodologicznych sformułowano problem badawczy, cele oraz cztery hipotezy badawcze, które poddano wery...

Polychlorinated naphthalenes (PCNs) in riverine and marine sediments of the Laizhou Bay area, North China

International Nuclear Information System (INIS)

Pan Xiaohui; Tang Jianhui; Chen Yingjun; Li Jun; Zhang Gan

2011-01-01

PCN congeners were analyzed in marine and riverine sediments of the Laizhou Bay area, North China. Concentrations of PCNs ranged from 0.12 to 5.1 ng g -1 dry weight (dw) with a mean value of 1.1 ng g -1 dw. The levels of PCNs varied largely, with industrial group approximately ten folds higher than those of the rural in riverine sediment. A strong impact by direct discharge from local factories was suggested. Similar compositional profiles were found within groups. High resemblance of compositional profiles between industrial samples and Halowax 1014 was observed. It was indicated that PCNs in riverine sediments were mainly from release of industrial usage, with additional contributions from industrial thermal process at certain sites. In marine sediments, it was suggested that PCNs along the coast of Laizhou Bay were mainly controlled by riverine input. While in the central bay, PCN distributions were possibly impacted by combined multiple factors. - Highlights: → We investigated the PCN levels both in the riverine and marine surface sediments of Laizhou Bay. → PCN concentrations in the river sediments of industrial group were ten times higher than in the rural group. → Leakage from industrial materials and thermal processes were the major sources. → PCNs in the coastal sites were more influenced by the river discharge. → In the centre bay, PCN distributions were possibly impacted by combined multiple factors. - A systematic sampling of riverine and marine sediments was conducted in Laizhou Bay area to investigate the distribution and possible sources of PCNs.

Microbially catalyzed nitrate-dependent metal/radionuclide oxidation in shallow subsurface sediments

Science.gov (United States)

Weber, K.; Healy, O.; Spanbauer, T. L.; Snow, D. D.

2011-12-01

enumeration of nitrate-dependent U(IV) oxidizing microorganisms demonstrated an abundant community ranging from 1.61x104 to 2.74x104 cells g-1 sediment. Enrichments initiated verified microbial U reduction and U oxidation coupled to nitrate reduction. Sediment slurries were serially diluted and incubated over a period of eight weeks and compared to uninoculated controls. Oxidation (0-4,554 μg/L) and reduction (0-55 μg/L) of U exceeded uninoculated controls further providing evidence of a U biogeochemical cycling in these subsurface sediments. The oxidation of U(IV) could contribute to U mobilization in the groundwater and result in decreased water quality. Not only could nitrate serve as an oxidant, but Fe(III) could also contribute to U mobilization. Nitrate-dependent Fe(II) oxidation is an environmentally ubiquitous process facilitated by a diversity of microorganisms. Additional research is necessary in order to establish a role of biogenic Fe(III) oxides in U geochemical cycling at this site. These microbially mediated processes could also have a confounding effect on uranium mobility in subsurface environments.

Sediment accumulation rates and geochronologies measured in the Saguenay Fjord using the Pb-210 dating method

Energy Technology Data Exchange (ETDEWEB)

Smith, J N; Walton, A [Department of Fisheries and Oceans, Dartmouth, N.S. (Canada). Atlantic Oceanographic Lab., Bedford Inst. of Oceanography

1980-02-01

Sediment accumulation rates were estimated from the vertical distribution of excess Pb-210 measured in sediment cores collected at seven stations in the Saguenay Fjord, Quebec. These rates decrease with increasing water depth and distance from the mouth of the Saguenay River, ranging from 4.0 g cm/sup -2/yr/sup -1/ (approximately = 7 cm yr/sup -1/) near the head of the fjord to 0.07 g cm/sup -2/yr/sup -1/ (approximately 0.1 cm yr/sup -1/) in the deep inner basin of the fjord. In one core from the head of the fjord, layered sediment structures, having different physical characteristics and composition, appear related to recent pulsed inputs of older raised marine deposits displaced by a landslide in 1971. Synchronous depositional anomalies in several cores provide evidence of other large scale sediment redistribution processes in the fjord. Pb-210 geochronologies are generally in good agreement with time-stratigraphic horizons inferred both from Cs-137 activity profiles and from the analysis of pollen assemblages in one core. (author).

The plasminogen activator inhibitor-1 (PAI-1) gene -844 A/G and -675 4G/5G promoter polymorphism significantly influences plasma PAI-1 levels in women with polycystic ovary syndrome.

Science.gov (United States)

Lin, Sun; Huiya, Zhang; Bo, Liu; Wei, Wei; Yongmei, Guan

2009-12-01

Mutations in the plasminogen activator inhibitor-1 (PAI-1) gene, along with increased PAI-1 levels, have been implicated in the pathogenesis of polycystic ovarian syndrome (PCOS). We investigated a possible influence of the promoter polymorphism (-844 A/G and -675 4G/5G) in the PAI-1 gene on plasma PAI-1 levels in 126 PCOS patients and 97 healthy controls. Levels of total testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH), fasting plasma glucose (FPG), fasting insulin, and PAI-1 were measured, and body mass index (BMI), waist-to-hip ratio (WHR), LH/FSH ratio, and homeostasis model assessment for insulin resistance (HOMA-IR) were calculated. PAI-1 -675 4G/5G and -844 A/G gene polymorphisms were also performed. Total testosterone, fasting insulin, and PAI-1 levels; BMI, LH/FSH, and HOMA-IR were significantly higher in PCOS patients than controls (P 5G or 5G/5G genotype. The plasma PAI-1 levels of the combination of the PAI-1 -844 A/A and -675 4G/4G or 4G/5G genotypes, or the coadunation of 4G/4G and -844 non-G/G (A/A + A/G) genotypes were significantly high in PCOS women compared with controls. A trend to a positive interaction between PAI-1 -675 4G/5G and -844 A/G gene polymorphism may elevate plasma PAI-1 levels and hypofibrinolysis, which is probably an important hereditary risk factor in PCOS.

[Limnology of high mountain tropical lake, in Ecuador: characteristics of sediments and rate of sedimentation].

Science.gov (United States)

Gunkel, Günter

2003-06-01

Equatorial high mountain lakes are a special type of lake occurring mainly in the South American Andes as well as in Central Africa and Asia. They occur at altitudes of a few thousand meters above sea level and are cold-water lakes (limnological study was therefore undertaken at Lake San Pablo, Ecuador, to analyze the basic limnological processes of the lake, which has a tendency for eutrophication. Sediment quality of San Pablo Lake is given under consideration of horizontal and vertical distribution using sediment cores. Significance of sediments for eutrophication process of lakes is demonstrated using phosphorus concentration of sediments as well as the phosphorus retention capacity of the sediments by ratio Fe/P. Dating of the sediments is done using 137Cs and 210Pb, but the activity of 137Cs in the sediment was very low nearly at the detection level. Sedimentation rate is determined to be 3.5 mm/year and the sediment cores represent about 110 years. P concentration of the sediments is high (approximately 5 g/kg dry substance), and P retention capacity by Fe is insufficient (Fe/P = 4). The sediment quality did not change significantly during the past decades, and the trophic state of San Pablo Lake was already less or more eutrophic 110 years ago. The contamination of the lake sediments by heavy metals is insignificant.

Irradiated graphite studies prior to decommissioning of G1, G2 and G3 reactors

International Nuclear Information System (INIS)

Bonal, J.P.; Vistoli, J.Ph.; Combes, C.

2005-01-01

G1 (46 MW th ), G2 (250 MW th ) and G3 (250 MW th ) are the first French plutonium production reactors owned by CEA (Commissariat a l'Energie Atomique). They started to be operated in 1956 (G1), 1959 (G2) and 1960 (G3); their final shutdown occurred in 1968, 1980 and 1984 respectively. Each reactor used about 1200 tons of graphite as moderator, moreover in G2 and G3, a 95 tons graphite wall is used to shield the rear side concrete from neutron irradiation. G1 is an air cooled reactor operated at a graphite temperature ranging from 30 C to 230 C; G2 and G3 are CO 2 cooled reactors and during operation the graphite temperature is higher (140 C to 400 C). These reactors are now partly decommissioned, but the graphite stacks are still inside the reactors. The graphite core radioactivity has decreased enough so that a full decommissioning stage may be considered. Conceming this decommissioning, the studies reported here are: (i) stored energy in graphite, (ii) graphite radioactivity measurements, (iii) leaching of radionuclide ( 14 C, 36 Cl, 63 Ni, 60 Co, 3 H) from graphite, (iv) chlorine diffusion through graphite. (authors)

Fodder radish cake (Raphanus sativus L. as an alternative biomass for the production of cellulases and xylanases in solid-state cultivation

Directory of Open Access Journals (Sweden)

L. Zukovski

Full Text Available Abstract Fodder radish (FR is an oilseed crop with a high potential for biodiesel production due to its high productivity and the quality of its seed oil. FR oil extraction results in a residue that is rich in protein and fiber. In this study, FR cake (FRC was evaluated as carbon and nitrogen source for the production of cellulases and xylanases using Penicillium echinulatum S1M29 during solid-state cultivation. It was determined that it is possible to partially replace wheat bran (WB by FRC, resulting in 24.22 ± 0.25U/g Filter Paper Activity (144 hours, 210.5 ± 5.8U/g endoglucanase activity (144 hours, 22.62 ± 0.01U/g (-glucosidase activity (96 hours and 784.7 ± 70.19U/g xylanase activity (120 hours. These values are equal or higher than the enzymatic activity obtained using WB. These results may contribute to the reduction of the cost of enzymes used in the production of cellulosic ethanol or other biotechnological applications.

Plasminogen activator inhibitor 1 4G/5G and -844G/A variants in idiopathic recurrent pregnancy loss.

Science.gov (United States)

Magdoud, Kalthoum; Herbepin, Viviana G; Touraine, Renaud; Almawi, Wassim Y; Mahjoub, Touhami

2013-09-01

Plasminogen activator inhibitor type 1 (PAI-1) regulates fibrinolysis, and the common promoter region variants -675G/A (4G/5G) and -844G/A are associated with increased thrombotic risk. Despite evidence linking altered fibrinolysis with adverse pregnancy events, including idiopathic recurrent pregnancy loss (RPL), the contribution of PAI-1 variants to RPL risk remains controversial. We investigated the association between the PAI-1 -844G/A and 4G/5G (-675G/A) variants with altered risk of RPL. This was a case-control study involving 304 women with confirmed RPL and 371 age- and ethnically matched control women. PAI-1 genotyping was performed by PCR single-specific primer -675 (G/A) and real-time PCR (-844G/A) analysis. Minor allele frequency (MAF) of 4G/5G (P 5G single-nucleotide polymorphism (SNP) was significantly associated with RPL under additive, dominant, and recessive genetic models; no association of -844G/A with RPL was seen irrespective of the genetic model tested. Taking common -844G/5G haplotype as reference (OR = 1.00), multivariate analysis confirmed the association of 4G-containing -844A/4G (P 5G, but not -844G/A, PAI-1 variant is associated with an increased risk of RPL. © 2013 John Wiley & Sons Ltd.

Spatial Variability of Metals in Surface Water and Sediment in the Langat River and Geochemical Factors That Influence Their Water-Sediment Interactions

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Wan Ying Lim

2012-01-01

Full Text Available This paper determines the controlling factors that influence the metals’ behavior water-sediment interaction facies and distribution of elemental content (75As, 111Cd, 59Co, 52Cr, 60Ni, and 208Pb in water and sediment samples in order to assess the metal pollution status in the Langat River. A total of 90 water and sediment samples were collected simultaneously in triplicate at 30 sampling stations. Selected metals were analyzed using ICP-MS, and the metals’ concentration varied among stations. Metal concentrations of water ranged between 0.08–24.71 μg/L for As, <0.01–0.53 μg/L for Cd, 0.06–6.22 μg/L for Co, 0.32–4.67 μg/L for Cr, 0.80–24.72 μg/L for Ni, and <0.005–6.99 μg/L for Pb. Meanwhile, for sediment, it ranged between 4.47–30.04 mg/kg for As, 0.02–0.18 mg/kg for Cd, 0.87–4.66 mg/kg for Co, 4.31–29.04 mg/kg for Cr, 2.33–8.25 mg/kg for Ni and 5.57–55.71 mg/kg for Pb. The average concentration of studied metals in the water was lower than the Malaysian National Standard for Drinking Water Quality proposed by the Ministry of Health. The average concentration for As in sediment was exceeding ISQG standards as proposed by the Canadian Sediment Quality Guidelines. Statistical analyses revealed that certain metals (As, Co, Ni, and Pb were generally influenced by pH and conductivity. These results are important when making crucial decisions in determining potential hazardous levels of these metals toward humans.

Occurrence of perfluorinated alkyl substances in sediment from estuarine and coastal areas of the East China Sea.

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Yan, Hong; Zhang, Chaojie; Zhou, Qi; Yang, Shouye

2015-02-01

Perfluorinated alkyl substances (PFAS) have drawn much attention due to their environmental persistence, ubiquitous existence, and bioaccumulation potential. The occurrence and spatial variation of PFAS were investigated through collection of riverine and marine sediments from estuarine and coastal areas of the East China Sea. Among them, perfluorooctanesulfonic acid (PFOS), perfluoroheptanoic acid (PFHpA), and perfluorooctanoic acid (PFOA) were the three predominant PFAS with the highest detection frequencies in the sediment. PFOS up to 32.4 ng g(-1) dw and ∑PFAS up to 34.8 ng g(-1) dw were detected. Compared to other studies, high levels of PFOS were found in sediments from the East China Sea. PFHpA was also detected at higher frequency and concentration than those of other studies, which suggests point sources in this area. Concentrations of PFAS in riverine sediments were much higher than in marine sediments. Analysis of spatial variations presented overall decreasing trends of PFAS from inshore to offshore areas.

Nitrogen Fixation in the Intertidal Sediments of the Yangtze Estuary: Occurrence and Environmental Implications

Science.gov (United States)

Hou, Lijun; Wang, Rong; Yin, Guoyu; Liu, Min; Zheng, Yanling

2018-03-01

Nitrogen fixation is a microbial-mediated process converting atmospheric dinitrogen gas to biologically available ammonia or other molecules, and it plays an important role in regulating nitrogen budgets in coastal marine ecosystems. In this study, nitrogen fixation in the intertidal sediments of the Yangtze Estuary was investigated using nitrogen isotope tracing technique. The abundance of nitrogen fixation functional gene (nifH) was also quantified. The measured rates of sediment nitrogen fixation ranged from 0.37 to 7.91 nmol N g-1 hr-1, while the abundance of nifH gene varied from 2.28 × 106 to 1.28 × 108 copies g-1 in the study area. The benthic nitrogen fixation was correlated closely to the abundance of nifH gene and was affected significantly by salinity, pH, and availability of sediment organic carbon and ammonium. It is estimated that sediment nitrogen fixation contributed approximately 9.3% of the total terrigenous inorganic nitrogen transported annually into the Yangtze estuarine and coastal environment. This result implies that the occurrence of benthic nitrogen fixation acts as an important internal source of reactive nitrogen and to some extent exacerbates nitrogen pollution in this aquatic ecosystem.

Regeneration dynamics of potassium-based sediment sorbents for CO{sub 2} capture

Energy Technology Data Exchange (ETDEWEB)

Wang, Li-wei; Diao, Yong-fa; Wang, Lin-lin; Shi, Xiao-fang; Tai, Xiao-yan [Donghua University, Shanghai (China)

2013-08-15

Simulating regeneration tests of Potassium-Based sorbents that supported by Suzhou River Channel Sediment were carried out in order to obtain parameters of regeneration reaction. Potassium-based sediment sorbents have a better morphology with the surface area of 156.73 m{sup 2}·g{sup −1}, the pore volume of 357.5x10{sup −3} cm{sup 3}·g{sup −1} and the distribution of pore diameters about 2-20 nm. As a comparison, those of hexagonal potassium-based sorbents are only 2.83 m{sup 2}g{sup −1}, 7.45x10{sup −3} cm{sup 3}g{sup −1} and 1.72-5.4 nm, respectively. TGA analysis shows that the optimum final temperature of regeneration is 200 and the optimum loading is about 40%, with the best heating rate of 10 .deg. C·min{sup −1}. By the modified Coats-Redfern integral method, the activation energy of 40% KHCO{sub 3} sorbents is 102.43 kJ·mol{sup −1}. The results obtained can be used as basic data for designing and operating CO{sub 2} capture process.

Distribution of Linear Alkylbenzenes (LABs in Sediments of Sarawak and Sembulan Rivers, Malaysia

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Sami Muhsen Magam

2012-01-01

Full Text Available The current study is one of the first studies evaluating the levels of linear alkylbenzenes (LABs in surface sediments of Sarawak and Sembulan rivers which are located in the east coast of Malaysia. The LABs, which are molecular tracers of sewage contamination, were measured in 15 surface sediment samples collected from these rivers. The samples were extracted, fractioned and analyzed by gas chromatography mass spectrometry (GC-MS. The findings revealed that the concentrations of ∑LABs ranged from 156.47 to 7386.19 ng/g dry weight (dw in the sediments of Sarawak River and from 643.18 to 5567.12 ng/g dw in the sediments of Sembulan River. The highest LABs levels were detected in the sediments collected from the sampling location SS9 in Sembulan River whereas the lowest levels were observed in the SS1 sampling location in Sarawak River. The I/E ratios (ratio of internal to external isomers of LABs for Sarawak River sediments ranged from 0.52 to 0.98 while for Sembulan River they fell within the range 0.87-1.79. The I/E ratio at the sampling station SS4 was much lower than the I/E ratios at the other stations, thus indicating that the wastewater discharged into Sarawak River from the areas surrounding station SS4 was poorly treated.

Cadmium distribution in coastal sediments and mollusks of the US

International Nuclear Information System (INIS)

Apeti, Dennis A.; Lauenstein, Gunnar G.; Riedel, Gerhardt F.

2009-01-01

Cadmium (Cd) concentrations in the coastal United States were assessed using the National Status and Trends (NS and T) Mussel Watch dataset, which is based on the analysis of sediments and bivalves collected from 280 sites since 1986. Using the 1997 sediment data, Pearson correlation (r = 0.44, p < 0.0001) suggested that Cd distributions in sediment can, be to some extent, explained by the proximity of sites to population centers. The 2003 tissue data indicated that 'high' Cd concentrations (greater than 5.6 μg/g dry weights [dw] for mussel and 5.4 μg/g dw for oysters) were related to salinity along the East and Gulf coasts. Along the West coast, however, these 'high' sites appeared to be related to upwelling phenomenon. Additionally, sedimentary diagenesis was found to be the most likely explanation of why sediment and mollusk Cd content were not well correlated.

Petroleum hydrocarbon assessment in the sediments of the northeastern Havana littoral, Cuba

Energy Technology Data Exchange (ETDEWEB)

Companioni Dams, Eloy Yordad; Nunez Clemente, Ana Catalina; Cora Medina, Miriam Odette [Laboratorio de Quimica Ambiental, Centro de Investigaciones del Petroleo, Habana (Cuba)]. E-mail: elocompa@yahoo.com; Gonzalez Brovo, Luis [Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear, Habana, (Cuba); Marbot Ramada, Rolando [Laboratorio de Quimica Analitica, Centro de Investigaciones del Petroleo, Habana (Cuba); Montes de Oca Porto, Rodny [Laboratorio Antidoping, Habana (Cuba); Rosabal Rodriguez, Maikel [Centro de Ingenieria y Manejo Ambiental de Bahias y Costas, Habana (Cuba); Diaz Diaz, Miguel angel [Laboratorio de Quimica Ambiental, Centro de Investigaciones del Petroleo, Habana (Cuba)

2009-02-15

As a part of a geochemical study, aliphatic and aromatic hydrocarbons were determined in surficial sediments, from a Cuban coastal zone located in the Northeastern Havana Littoral. Sediment samples were collected at 15 sites in this area, and then extracted and analyzed by gas chromatography with flame ionization and mass spectrometry detectors. Total concentration of both, aliphatic (AH) and aromatic (ArH) hydrocarbons, varied from 2.4 {+-} 0.2 to 105.1 {+-} 5.9 {mu}g/g (dry weight) and from 1.1 {+-} 0.2 to 38.4 {+-} 7.6 {mu}g/g (dry weight), respectively. The chromatography profile of AH was dominated by an unresolved complex mixture (UCM), and the presence of isoprenoid hydrocarbons, steranes and hopanes, indicated petroleum - related hydrocarbon inputs. The predominant concentration of phytoplanktonic molecular markers (pristane and nC17) in collected sediments, revealed the marine productivity in this sites. The anthropogenic contribution detected showed the impact of the petroleum exploration along this coastal area. [Spanish] Como parte de un estudio geoquimico se determinaron hidrocarburos alifaticos y aromaticos en sedimentos superficiales, de una zona costera situada en el Litoral Nordeste de La Habana. Las muestras de sedimento se colectaron en 15 estaciones de muestreo en esta area, y posteriormente se extrajeron y analizaron mediante cromatografia gaseosa con detectores de ionizacion a la llama y espectrometria de masas. Las concentraciones totales de hidrocarburos alifaticos (HA) e hidrocarburos aromaticos (HAr) variaron desde 2.4 {+-} 0.2 a 105.1 {+-} 5.9 {mu}g/g (peso eco) y desde 1.1 {+-} 0.2 a 38.4 {+-} 7.6 {mu}g/g (peso eco), respectivamente. El perfil cromatografico de los hidrocarburos alifaticos estuvo dominado por una mezcla compleja no resuelta (MCNR), y la presencia de hidrocarburos isoprenoides, esteranos y hopanos, indico el aporte de hidrocarburos derivados del petroleo. La concentracion predominante de marcadores moleculares

The sediment budget of an urban coastal lagoon (Jamaica Bay, NY) determined using 234Th and 210Pb

Science.gov (United States)

Renfro, Alisha A.; Cochran, J. Kirk; Hirschberg, David J.; Bokuniewicz, Henry J.; Goodbred, Steven L.

2016-10-01

The sediment budget of Jamaica Bay (New York, USA) has been determined using the natural particle-reactive radionuclides 234Th and 210Pb. Inventories of excess thorium-234 (234Thxs, half-life = 24.1 d) were measured in bottom sediments of the Bay during four cruises from September 2004 to July 2006. The mean bay-wide inventory for the four sampling periods ranged from 3.5 to 5.0 dpm cm-2, four to six times that expected from 234Th production in the overlying water column. The presence of dissolved 234Th and a high specific activity of 234Thxs on particles at the bay inlet (∼30 dpm g-1) indicated that both dissolved and particulate 234Th could be imported into the bay from the ocean. Based on these observations, a mass balance of 234Th yields an annual input of ∼39 ± 14 × 1010 g sediment into the bay. Mass accumulation rates determined from profiles of excess 210Pb (half-life = 22.3 y) in sediment cores require annual sediment import of 7.4 ± 4.5 × 1010 g. Both radionuclides indicate that there is considerable marine-derived sediment import to Jamaica Bay, consistent with earlier work using 210Pb. Such sediment input may be important in sustaining longer-term accretion rates of salt marshes in the bay.

Age-dependent mixing of deep-sea sediments

International Nuclear Information System (INIS)

Smith, C.R.; Maggaard, L.; Pope, R.H.; DeMaster, D.J.

1993-01-01

Rates of bioturbation measured in deep-sea sediments commonly are tracer dependent; in particular, shorter lived radiotracers (such as 234 Th) often yield markedly higher diffusive mixing coefficients than their longer-lived counterparts (e.g., 210 Pb). At a single station in the 1,240-m deep Santa Catalina Basin, the authors document a strong negative correlation between bioturbation rate and tracer half-life. Sediment profiles of 234 Th (half-life = 24 days) yield an average mixing coefficient (60 cm 2 y -1 ) two orders of magnitude greater than that for 210 Pb (half-life = 22 y, mean mixing coefficient = 0.4 cm 2 y -1 ). A similar negative relationship between mixing rate and tracer time scale is observed at thirteen other deep-sea sites in which multiple radiotracers have been used to assess diffusive mixing rates. This relationship holds across a variety of radiotracer types and time scales. The authors hypothesize that this negative relationship results from age-dependent mixing, a process in which recently sedimented, food-rich particles are ingested and mixed at higher rates by deposit feeders than are older, food-poor particles. Results from an age-dependent mixing model demonstrate that this process indeed can yield the bioturbation-rate vs. tracer-time-scale correlations observed in deep-sea sediments. Field data on mixing rates of recently sedimented particles, as well as the radiotracer activity of deep-sea deposit feeders, provide strong support for the age-dependent mixing model. The presence of age-dependent mixing in deep-sea sediments may have major implications for diagenetic modeling, requiring a match between the characteristic time scales of mixing tracers and modeled reactants. 102 refs., 6 figs., 5 tabs

Concentrations of Mn and Fe in the Sediment Cores of Sarawak and Sabah Coastal Waters

International Nuclear Information System (INIS)

Zal Uyun Wan Mahmood; Zaharudin Ahmad; Che Abdul Rahim Mohamed

2010-01-01

Sediment cores were taken at eight stations along Sarawak and Sabah coastal waters using a gravity box corer on July 2004. The sediment cores were cut into 2 cm interval for measurement of Mn and Fe concentration using the Inductive Couple Plasma-Mass Spectrometer (ICP-MS). Overall, the sediment cores contained much mud which include a mixture of silt (46 - 67 %) and clay (18 - 53 %) compared to sand (0.4 - 16 %). The concentrations of Mn and Fe were in the range of 154 - 366 μg/ g and 0.9 - 3.4 %, respectively. The variation was studied by ANOVA, which showed a significant difference (p = 0.000) for both of Mn and Fe concentrations at all sampling stations. In those ranges, Fe concentration was higher compared to Mn. It is believed that dissolving and diluting process influenced the concentration of Mn in the water column and sediment. Fe showed a significant correlation (r > 0.5, p geo < 1 and classification 0 - 1. (author)

Distribution and accumulation of polybrominated diphenyl ethers (PBDEs) in Hong Kong mangrove sediments.

Science.gov (United States)

Zhu, Haowen; Wang, Ying; Wang, Xiaowei; Luan, Tiangang; Tam, Nora F Y

2014-01-15

Polybrominated diphenyl ethers (PBDEs) have been used extensively as brominated flame retardants in various polymers, and have become serious environmental contaminants, particularly in coastal sediments. Mangrove wetlands are important coastal ecosystems in tropical and subtropical regions, and mangrove sediments are often the pollutant sinks due to their close proximity with human activities. In Hong Kong, sediment samples collected from five mangrove swamps were found to be contaminated with PBDEs and the eight measured BDE congeners, including BDE-28, -47, -99, -100, -153, -154, -183 and -209 were detected in all mangrove sediments, indicating that these pollutants were widespread in Hong Kong mangrove wetlands. Among the five swamps, relatively high concentrations of PBDEs were recorded in Mai Po mangrove swamp in the northwestern Hong Kong, which is part of the RAMSAR site but is severely influenced by the pollution from the Pearl River Delta. The depth profile of PBDEs in sediment cores collected from Mai Po also showed the inputs of PBDEs in this mangrove swamp increased year by year. In all sediments, the concentrations of BDE-209 were 1-2 orders of magnitude higher than the other congeners in the same sediment. The concentrations of BDE-209 and ∑PBDEs (defined as the sum of seven targeted BDE congeners except BDE-209) ranged from 1.53 to 75.9 ng g(-1) and from 0.57 to 14.4 ng g(-1), respectively. Among the targeted BDE congeners except BDE-209, slightly different composition was recorded among samples collected from different locations, with BDE-153 and -183 being the pre-dominated congeners. In all mangrove swamps, except Tai O in the southwest of Hong Kong, ∑PBDEs concentrations showed a common trend of landward>seaward>mudflat. The concentrations of ∑PBDEs were significantly correlated with total organic matter (TOM) content in sediments but not with the sediment particle sizes in each mangrove swamp. © 2013.

Transport and inventory of mercury from point sources in Haifa Bay. Final report for the period 15 April 1995 - 15 April 1996

International Nuclear Information System (INIS)

Herut, B.

1996-09-01

The purpose of this study was to examine the main sinks and transport mechanisms of anthropogenic mercury in the Northern part of Haifa Bay. Haifa Bay is located at the Northern Mediterranean coast of Israel. Mercury has been constantly introduced into the Northern part of the Bay since the opening of a chlor-alkali plant in 1956. Between 1975-79 the flux was drastically reduced after installation of pollution abatements and in 1981 it was reduced further to its present level of 30 kg yr- 1 . The total calculated amount of mercury introduced to the Bay during the last 38 years is about 19,300 kg. Mercury inventory in sediments of the inner Northern part of Haifa bay was calculated by backwards extrapolation of the total amount of mercury which could have been present in the top 50 cm sediments if only accumulation processes occurred. The amount trapped in the sediments accounted for only approximately 10% of the total estimated amount of anthropogenic mercury. Part of the missing mercury settled in the sediments of the outer Bay and a significant part was transported seaward by mercury-laden particles and as resuspended near shore sediments. Indeed, relatively high concentrations of suspended particulate matter (1-3 mg 1- 1 ) with mercury concentrations (1-10 ug g- 1 ) of one order of magnitude higher than in the surface sediments were sampled in the area opposite the chlor-alkali plant. The total amount of mercury in the samples was measured by cold vapor atomic absorption spectrometry on a Coleman Mercury Analyser MAS-50A. 2 figs

234Th/238U disequilibrium in near-shore sediment: particle reworking and diagenetic time scales

International Nuclear Information System (INIS)

Aller, R.C.; Cochran, J.K.

1976-01-01

The distribution of 234 Th (tsub(1.2)=24.1 days) in excess of its parent 238 U in the upper layers of near-shore sediment makes possible the evaluation of short-term sediment reworking and diagenetic rates. 234 Th has a maximum residence time in Long Island Sound water of 1.4 days. Seasonal measurement of 234 Th/ 238 U disequilibrium in sediment at a single station in central Long Island Sound demonstrates rapid particle reworking and high 234 Thsub(XS)(>1 dpm/g) in the upper 4 cm of sediment with slower, irregular reworking and low 234 Thsub(XS) to at least 12 cm. The rate of rapid particle reworking varies seasonally and is highest in the fall. The rapidly mixed zone is characterized by steep gradients in sediment chemistry implying fast reactions spanned by 234 Th decay time scales. 238 U is depleted in the upper mixed zone and shows addition in reducing sediment at depth. (Auth.)

Evaluation of the effect of temperature, pH, and bioproduction on Hg concentration in sediments, water, molluscs and algae of the delta of the Ebro river.

Science.gov (United States)

Schuhmacher, M; Domingo, J L; Llobet, J M; Corbella, J

1993-01-01

The effects of temperature, pH, and bioproduction on mercury levels in sediments, water, molluscs and algae from the delta of the Ebro river (NE Spain) were determined in this study. Mercury concentrations were measured in a cold-vapor atomic absorption spectrophotometer. The ranges of mercury concentrations were the following: sediments, 0.014-0.185 microgram g-1; water, 0.001-0.018 microgram g-1; molluscs, 0.118-0.861 microgram g-1; and algae 0.008-0.026 microgram g-1. Although not statistically significant, a decrease in the pH of the water corresponded with a diminution in the content of mercury in sediments and molluscs, while the mercury levels in water and algae were lower in the areas with high levels of bioproduction. The concentrations of mercury in water significantly decreased with temperature. However, the differences with temperature of the mercury concentrations in sediments did not reach the level of significance. Consequently, water would not be an adequate indicator to determine the levels of mercury contamination, although both sediments and molluscs can be used for this purpose.

Spatial distribution and source apportionment of PFASs in surface sediments from five lake regions, China.

Science.gov (United States)

Qi, Yanjie; Huo, Shouliang; Xi, Beidou; Hu, Shibin; Zhang, Jingtian; He, Zhuoshi

2016-03-07

Perfluoroalkyl substances (PFASs) have been found in environment globally. However, studies on PFAS occurrence in sediments of lakes or reservoirs remain relatively scarce. In this study, two hundred and sixty-two surface sediment samples were collected from forty-eight lakes and two reservoirs all over China. Average PFAS concentrations in surface sediments from each lake or reservoir varied from 0.086 ng/g dw to 5.79 ng/g dw with an average of 1.15 ng/g dw. Among five lake regions, average PFAS concentrations for the lakes from Eastern Plain Region were the highest. Perfluorooctanoic acid, perfluoroundecanoic acid and perfluorooctane sulfonic acid (PFOS) were the predominant PFASs in surface sediments. The significant positive correlations between PFAS concentrations and total organic carbon, total nitrogen and total phosphorus contents in sediments revealed the influences of sedimentary characteristics on PFAS occurrence. A two-dimensional hierarchical cluster analysis heat map was depicted to analyze the possible origins of sediments and individual PFAS. The food-packaging, textile, electroplating, firefighting and semiconductor industry emission sources and the precious metals and coating industry emission sources were identified as the main sources by two receptor models, with contributions of 77.7 and 22.3% to the total concentrations of C4-C14- perfluoroalkyl carboxylic acids and PFOS, respectively.

Impacts of Sediments on Coral Energetics: Partitioning the Effects of Turbidity and Settling Particles

Science.gov (United States)

Junjie, Reef K.; Browne, Nicola K.; Erftemeijer, Paul L. A.; Todd, Peter A.

2014-01-01

Sediment loads have long been known to be deleterious to corals, but the effects of turbidity and settling particles have not previously been partitioned. This study provides a novel approach using inert silicon carbide powder to partition and quantify the mechanical effects of sediment settling versus reduced light under a chronically high sedimentary regime on two turbid water corals commonly found in Singapore (Galaxea fascicularis and Goniopora somaliensis). Coral fragments were evenly distributed among three treatments: an open control (30% ambient PAR), a shaded control (15% ambient PAR) and sediment treatment (15% ambient PAR; 26.4 mg cm−2 day−1). The rate of photosynthesis and respiration, and the dark-adapted quantum yield were measured once a week for four weeks. By week four, the photosynthesis to respiration ratio (P/R ratio) and the photosynthetic yield (Fv/Fm) had fallen by 14% and 3–17% respectively in the shaded control, contrasting with corals exposed to sediments whose P/R ratio and yield had declined by 21% and 18–34% respectively. The differences in rates between the shaded control and the sediment treatment were attributed to the mechanical effects of sediment deposition. The physiological response to sediment stress differed between species with G. fascicularis experiencing a greater decline in the net photosynthetic yield (13%) than G. somaliensis (9.5%), but a smaller increase in the respiration rates (G. fascicularis = 9.9%, G. somaliensis = 14.2%). These different physiological responses were attributed, in part, to coral morphology and highlighted key physiological processes that drive species distribution along high to low turbidity and depositional gradients. PMID:25197883

Impacts of sediments on coral energetics: partitioning the effects of turbidity and settling particles.

Directory of Open Access Journals (Sweden)

Reef K Junjie

Full Text Available Sediment loads have long been known to be deleterious to corals, but the effects of turbidity and settling particles have not previously been partitioned. This study provides a novel approach using inert silicon carbide powder to partition and quantify the mechanical effects of sediment settling versus reduced light under a chronically high sedimentary regime on two turbid water corals commonly found in Singapore (Galaxea fascicularis and Goniopora somaliensis. Coral fragments were evenly distributed among three treatments: an open control (30% ambient PAR, a shaded control (15% ambient PAR and sediment treatment (15% ambient PAR; 26.4 mg cm(-2 day(-1. The rate of photosynthesis and respiration, and the dark-adapted quantum yield were measured once a week for four weeks. By week four, the photosynthesis to respiration ratio (P/R ratio and the photosynthetic yield (Fv/Fm had fallen by 14% and 3-17% respectively in the shaded control, contrasting with corals exposed to sediments whose P/R ratio and yield had declined by 21% and 18-34% respectively. The differences in rates between the shaded control and the sediment treatment were attributed to the mechanical effects of sediment deposition. The physiological response to sediment stress differed between species with G. fascicularis experiencing a greater decline in the net photosynthetic yield (13% than G. somaliensis (9.5%, but a smaller increase in the respiration rates (G. fascicularis = 9.9%, G. somaliensis  = 14.2%. These different physiological responses were attributed, in part, to coral morphology and highlighted key physiological processes that drive species distribution along high to low turbidity and depositional gradients.

Toxicity of smelter slag-contaminated sediments from Upper Lake Roosevelt and associated metals to early life stage White Sturgeon (Acipenser transmontanus Richardson, 1836)

Science.gov (United States)

Little, E.E.; Calfee, R.D.; Linder, G.

2014-01-01

The toxicity of five smelter slag-contaminated sediments from the upper Columbia River and metals associated with those slags (cadmium, copper, zinc) was evaluated in 96-h exposures of White Sturgeon (Acipenser transmontanus Richardson, 1836) at 8 and 30 days post-hatch. Leachates prepared from slag-contaminated sediments were evaluated for toxicity. Leachates yielded a maximum aqueous copper concentration of 11.8 μg L−1 observed in sediment collected at Dead Man's Eddy (DME), the sampling site nearest the smelter. All leachates were nonlethal to sturgeon that were 8 day post-hatch (dph), but leachates from three of the five sediments were toxic to fish that were 30 dph, suggesting that the latter life stage is highly vulnerable to metals exposure. Fish maintained consistent and prolonged contact with sediments and did not avoid contaminated sediments when provided a choice between contaminated and uncontaminated sediments. White Sturgeon also failed to avoid aqueous copper (1.5–20 μg L−1). In water-only 96-h exposures of 35 dph sturgeon with the three metals, similar toxicity was observed during exposure to water spiked with copper alone and in combination with cadmium and zinc. Cadmium ranging from 3.2 to 41 μg L−1 or zinc ranging from 21 to 275 μg L−1 was not lethal, but induced adverse behavioral changes including a loss of equilibrium. These results suggest that metals associated with smelter slags may pose an increased exposure risk to early life stage sturgeon if fish occupy areas contaminated by slags.

Influence of anthropogenic activities on PAHs in sediments in a significant gulf of low-latitude developing regions, the Beibu Gulf, South China Sea: distribution, sources, inventory and probability risk.

Science.gov (United States)

Li, Pingyang; Xue, Rui; Wang, Yinghui; Zhang, Ruijie; Zhang, Gan

2015-01-15

Fifteen polycyclic aromatic hydrocarbons (PAHs) in 41 surface sediment samples and a sediment core (50 cm) from the Beibu Gulf, a significant low-latitude developing gulf, were analyzed. PAHs concentrations were 3.01-388 ng g(-)(1) (mean 95.5 ng g(-)(1)) in the surface sediments and 10.5-87.1 ng g(-)(1) (average 41.1 ng g(-)(1)) in the sediment core. Source apportionment indicated that PAHs were generated from coke production and vehicular emissions (39.4%), coal and biomass combustion (35.8%), and petrogenic sources (24.8%). PAHs were mainly concentrated in the industrialized and urbanized regions and the harbor, and were transported by atmospheric deposition to the marine matrix. The mass inventory (1.57-2.62t) and probability risk showed sediments here served as an important reservoir but low PAH risk. Different from oil and natural gas in developed regions, coal combustion has always been a significant energy consumption pattern in this developing region for the past 30 years (56 ± 5%). Copyright © 2014 Elsevier Ltd. All rights reserved.

Butyltin compounds in sediment and molluscs from the shipping strait between Denmark and Sweden

International Nuclear Information System (INIS)

Strand, Jakob; Jacobsen, Jens A.; Pedersen, Britta; Granmo, Aake

2003-01-01

The deposit feeding bivalve Nuculana pernula is a suitable for monitoring bioavailability of TBT in sediment along a major shipping route. - The distribution of tributyltin (TBT) contamination in the subtidal zone of the waters between Denmark and Sweden was investigated in relation to major international shipping lanes. Sediment and different benthic molluscs were sampled in transects along and perpendicularly to the shipping lanes in the Sound (Oresund) and the Kattegat/Skagerrak region. The samples were analysed for TBT and its degradation products, dibutyltin (DBT) and monobutyltin (MBT), using GC-PFPD. In sediments, the TBT concentration ranged from -1 dry weight (dw) with a strong correlation between the TBT concentration and the organic fraction in sediment (r 2 =0.90) in the samples collected in the Sound, where the highest concentrations were found. This relationship was not observed in the samples from the Kattegat because the TBT concentration in most sediment samples was below the limit of detection. In the molluscs, TBT and its degradation products were detected in all samples from the entire area with concentrations ranging from 8.1 ng g -1 dw in Buccinum undatum to 1316 ng g -1 dw in Nuculana pernula. The deposit-feeding bivalve N. pernula was found to have a particularly high accumulation potential for TBT. In addition, a strong correlation between TBT concentrations in sediment and N. pernula was found. Therefore this species seems to be an ideal organism for monitoring sediment contamination. The TBT concentration in N. pernula was found to decrease gradually along the shipping lanes from the Sound, through the Kattegat and into the Skagerrak

Copper effects on bacterial activity of estuarine silty sediments

Science.gov (United States)

Almeida, Adelaide; Cunha, Ângela; Fernandes, Sandra; Sobral, Paula; Alcântara, Fernanda

2007-07-01

Bacteria of silty estuarine sediments were spiked with copper to 200 μg Cu g -1 dry weight sediment in order to assess the impact of copper on bacterial degradation of organic matter and on bacterial biomass production. Bacterial density was determined by direct counting under epifluorescence microscopy and bacterial production by the incorporation of 3H-Leucine. Leucine turnover rate was evaluated by 14C-leucine incorporation and ectoenzymatic activities were estimated as the hydrolysis rate of model substrates for β-glucosidase and leucine-aminopeptidase. The presence of added copper in the microcosms elicited, after 21 days of incubation, generalised anoxia and a decrease in organic matter content. The non-eroded surface of the copper-spiked sediment showed, when compared to the control, a decrease in bacterial abundance and significant lower levels of bacterial production and of leucine turnover rate. Bacterial production and leucine turnover rate decreased to 1.4% and 13% of the control values, respectively. Ectoenzymatic activities were also negatively affected but by smaller factors. After erosion by the water current in laboratory flume conditions, the eroded surface of the control sediment showed a generalised decline in all bacterial activities. The erosion of the copper-spiked sediment showed, however, two types of responses with respect to bacterial activities at the exposed surface: positive responses of bacterial production and leucine turnover rate contrasting with slight negative responses of ectoenzymatic activities. The effects of experimental erosion in the suspended cells were also different in the control and in the copper-spiked sediment. Bacterial cells in the control microcosm exhibited, when compared to the non-eroded sediment cells, decreases in all activities after the 6-h suspension. The response of the average suspended copper-spiked sediment cell differed from the control by a less sharp decrease in ectoenzymatic activities and

Promotion of hepatic preneoplastic lesions in male B6C3F1 mice by unleaded gasoline.

Science.gov (United States)

Standeven, A M; Wolf, D C; Goldsworthy, T L

1995-01-01

In previous studies, unleaded gasoline (UG) vapor was found to be a liver tumor promoter and hepatocarcinogen in female mice, but UG was not a hepatocarcinogen in male mice. However, UG vapor had similar transient mitogenic effects in nonlesioned liver of both male and female mice under the conditions of the cancer bioassay. We used an initiation-promotion protocol to determine whether UG vapor acts as a liver tumor promoter in male mice and to examine proliferative effects that may be critical to tumor development. Twelve-day-old male B6C3F1 mice were injected with N-nitrosodiethylamine (DEN; 5 mg/kg, intraperitoneally) or vehicle. Starting at 5-7 weeks of age, mice were exposed by inhalation 6 hr/day, 5 days/week for 16 weeks to 0 or 2046 ppm of PS-6 blend UG. UG treatment caused a significant 2.3-fold increase in the number of macroscopic hepatic masses in DEN-initiated mice, whereas no macroscopic masses were observed in non-initiated mice. Altered hepatic foci (AHF), which were predominantly basophilic in phenotype, were found almost exclusively in DEN-initiated mice. UG treatment significantly increased both the mean volume (threefold) and the volume fraction (twofold) of the AHF without increasing the number of AHF per unit area. UG also induced hepatic pentoxyresorufin-O-dealkylase (PROD) activity, a marker of CYP2B, by more than 12-fold over control with or without DEN cotreatment. To study hepatocyte proliferative effects of UG, we treated mice with 5-bromo-2'-deoxyuridine (BrdU) via osmotic pump for 3 days before necropsy and measured hepatocyte BrdU labeling index (LI) in AHF and nonlesioned liver.(ABSTRACT TRUNCATED AT 250 WORDS) Images Figure 1. PMID:7588481

The geochemistry of coprostanol in waters and surface sediments from Narragansett Bay

Science.gov (United States)

LeBlanc, Lawrence A.; Latimer, James S.; Ellis, John T.; Quinn, James G.

1992-05-01

1 -1) and surface sediments (0·22-33 μg g -1) were as high or higher than values reported in the literature, indicating that the estuary is impacted by sewage.

Ultrasonic destruction of albumin microbubbles enhances gene transfection and expression in cardiac myocytes.

Science.gov (United States)

Wang, Guo-zhong; Liu, Jing-hua; Lü, Shu-zheng; Lü, Yun; Guo, Cheng-jun; Zhao, Dong-hui; Fang, Dong-ping; He, Dong-fang; Zhou, Yuan; Ge, Chang-jiang

2011-05-01

It has been proven that ultrasonic destruction of microbubbles can enhance gene transfection efficiency into the noncardiac cells, but there are few reports about cardiac myocytes. Moreover, the exact mechanisms are not yet clear; whether the characteristic of microbubbles can affect the gene transfection efficiency or not is still controversial. This study was designed to investigate whether the ultrasound destruction of gene-loaded microbubbles could enhance the plasmids carried reporter gene transfection in primary cultured myocardial cell, and evaluate the effects of microbubbles characteristics on the transgene expression in cardiac myocytes. The β-galactosidase plasmids attached to the two types of microbubbles, air-contained sonicated dextrose albumin (ASDA) and perfluoropropane-exposed sonicated dextrose albumin (PESDA) were prepared. The gene transfection into cardiac myocytes was performed in vitro by naked plasmids, ultrasound exposure, ultrasonic destruction of gene-loaded microbubbles and calcium phosphate precipitation, and then the gene expression and cell viability were analyzed. The ultrasonic destruction of gene-loaded microbubbles enhanced gene expression in cardiac myocytes compared with naked plasmid transfection ((51.95 ± 2.41) U/g or (29.28 ± 3.65) U/g vs. (0.84 ± 0.21) U/g, P ASDA ((51.95 ± 2.41) U/g vs. (29.28 ± 3.65) U/g, P < 0.05). Ultrasonic destruction of microbubbles during calcium phosphate precipitation gene transfection enhanced β-galactosidase activity nearly 8-fold compared with calcium phosphate precipitation gene transfection alone ((111.35 ± 11.21) U/g protein vs. (14.13 ± 2.58) U/g protein, P < 0.01). Even 6 hours after calcium phosphate precipitation gene transfection, ultrasound-mediated microbubbles destruction resulted in more intense gene expression ((35.63 ± 7.65) U/g vs. (14.13 ± 2.58) U/g, P < 0.05). Ultrasonic destruction of microbubbles might be a promising method for the delivery of non-viral DNA into

Accumulation of Sellafield-derived radiocarbon ("1"4C) in Irish Sea and West of Scotland intertidal shells and sediments

International Nuclear Information System (INIS)

Tierney, Kieran M.; Muir, Graham K.P.; Cook, Gordon T.; MacKinnon, Gillian; Howe, John A.; Heymans, Johanna J.; Xu, Sheng

2016-01-01

The nuclear energy industry produces radioactive waste at various stages of the fuel cycle. In the United Kingdom, spent fuel is reprocessed at the Sellafield facility in Cumbria on the North West coast of England. Waste generated at the site comprises a wide range of radionuclides including radiocarbon ("1"4C) which is disposed of in various forms including highly soluble inorganic carbon within the low level liquid radioactive effluent, via pipelines into the Irish Sea. This "1"4C is rapidly incorporated into the dissolved inorganic carbon (DIC) reservoir and marine calcifying organisms, e.g. molluscs, readily utilise DIC for shell formation. This study investigated a number of sites located in Irish Sea and West of Scotland intertidal zones. Results indicate "1"4C enrichment above ambient background levels in shell material at least as far as Port Appin, 265 km north of Sellafield. Of the commonly found species (blue mussel (Mytilus edulis), common cockle (Cerastoderma edule) and common periwinkle (Littorina littorea)), mussels were found to be the most highly enriched in "1"4C due to the surface environment they inhabit and their feeding behaviour. Whole mussel shell activities appear to have been decreasing in response to reduced discharge activities since the early 2000s but in contrast, there is evidence of continuing enrichment of the carbonate sediment component due to in-situ shell erosion, as well as indications of particle transport of fine "1"4C-enriched material close to Sellafield. - Highlights: • We measure "1"4C activity in shells and sediment at sites on the UK west coast. • Mussel shell activity varies in response to average "1"4C discharges from Sellafield. • Shell activities reflect species feeding habits and ecological niche. • NE Irish Sea inorganic sediment activity will gradually increase. • Increases in sediment activity will occur at remote sites on the Scottish west coast.

Aliphatic and aromatic hydrocarbons in tropical recent sediments of Campos dos Goytacazes, RJ, Brazil

Directory of Open Access Journals (Sweden)

Gomes Alexandre de O.

2003-01-01

Full Text Available Sediment samples from the Imbé, the Urubu and the Ururaí rivers and from Lake de Cima were studied. These sites are located in the county of Campos dos Goytacazes, Rio de Janeiro, Brazil. Aliphatic and aromatic fractions were analyzed by GC-FID and GC-MS in order to gather information on the degree of contamination by anthropogenic activities and other biogenic contributions. Concentrations of total aliphatic and aromatic hydrocarbons were 1.2, 2.8, 5.8 and 4.3 mug g-1 and 74, 30, 722 and 340 ng g-1 in the Imbé, Ururaí, Urubu rivers and Lake de Cima, respectively. The C20 highly branched isoprenoid alkane was identified in the Urubu sediment. There were no hopanes or steranes in any sample. Anthropogenic aromatic compounds, detected at trace levels, were observed only in the Imbé and in Lake de Cima (227 ng g-1. The fluoranthene/pyrene rate for Lake de Cima was 4.2, suggesting a combustion origin for the PAH. This data is consistent with the frequently sugar cane burning practice that occurs in this region. A greater input from higher plants was observed in the Urubu, Imbé and Lake de Cima sediments; on the other hand, the aquatic input predominates for Ururaí. In summary, Lake de Cima sediment is considered very slightly polluted, while the others are unpolluted.

The prevalence of PAI-1 4G/5G gene variant in Serbian population

Directory of Open Access Journals (Sweden)

Đorđević Valentina

2013-01-01

Full Text Available Introduction: Plasminogen activator inhibitor 1 (PAI-1 has a major role in inhibition of firinolysis and normal haemostasis. The presence of the PAI-1 4G/4G genotype leads to increased expression of PAI-1. High blood level of PAI-1 is associated with many diseases such as thrombosis, cerebral insult, myocardial infarction, pregnancy loss, preeclampsia, insulin resistance, type 2 diabetes, breast cancer and asthma. In this study, the prevalence of PAI-1 4G/5G gene variant was determined in healthy subjects from Serbian population. Methods: The study was carried out in a group of 210 healthy subjects (105 women and 105 men. The presence of PAI-1 4G/5G gene variant was detected by PCR-RFLP analysis. Results: The prevalence of PAI-1 4G/4G genotype was 34.76% and it was increased compared to PAI-1 5G/5G genotype (19.05%. The most frequent was PAI-1 4G/5G genotype (46.19%. Allelic frequency for 4G allele was higher (0.58 compared to 5G allele (0.42. Conclusions: The prevalence of PAI-1 4G/5G gene variant in Serbian population is similar to the neighboring populations. Results of this study represent the first data for Serbian population. This study could be useful for further research where the role of PAI-1 4G/5G gene variant will be assessed in the pathogenesis of many diseases.

Lake sediment records of Quaternary climate change

International Nuclear Information System (INIS)

Moy, C.

2012-01-01

Lake sediment records provide an excellent means to reconstruct past climate and environmental change because they typically provide long, high-resolution and continuous archives of environmental change. Lake sediment records typically exhibit high sedimentation rates (centennial to millennial scale variability is common and annual resolution is possible in some sites), contain sedimentary components well-suited for a multi-proxy approach, multiple dating methods can be applied, tend to exhibit a broad geographic distribution, and are relatively accessible. Furthermore, a number of geochemical techniques can be applied to reconstruct components of the climate system based on the stable isotope geochemistry of carbonate or organic phases preserved and exposed in lacustrine sediment cores. Various stable isotope methods can be applied to lacustrine systems and these are a valuable tool that can be used to monitor physical processes (e.g. evaporation), vegetation dynamics within the watershed (C 3 vs C 4 plant distributions), biologic processes (aquatic productivity), all of which can be driven by a regional climate forcing. (author). 31 refs., 11 figs., 1 tab.

The influence of permanently submerged macrophytes on sediment mercury distribution, mobility and methylation potential in a brackish Norwegian fjord.

Science.gov (United States)

Olsen, Marianne; Schaanning, Morten Thorne; Braaten, Hans Fredrik Veiteberg; Eek, Espen; Moy, Frithjof E; Lydersen, Espen

2018-01-01

Macrophytes are shown to affect the microbial activity in different aqueous environments, with an altering of the sediment cycling of mercury (Hg) as a potential effect. Here, we investigated how a meadow with permanently submerged macrophytes in a contaminated brackish fjord in southern Norway influenced the conditions for sulfate reducing microbial activity, the methyl-Hg (MeHg) production and the availability of MeHg. Historically discharged Hg from a chlor-alkali plant (60-80tons, 1947-1987) was evident through high Hg concentrations (491mgTot-Hgkg -1 , 268μgMeHgkg -1 ) in intermediate sediment depths (10-20cm) outside of the meadow, with reduced concentrations within the meadow. Natural recovery of the fjord was revealed by lower sediment surface concentrations (1.9-15.5mgTot-Hgkg -1 , 1.3-3.2μgMeHgkg -1 ). Within the meadow, vertical gradients of sediment hydrogen sulfide (H 2 S) E h and pH suggested microbial sulfate reduction in 2-5cm depths, coinciding with peak values of relative MeHg levels (0.5% MeHg). We assume that MeHg production rates was stimulated by the supply and availability of organic carbon, microbial activity and a sulfide oxidizing agent (e.g. O 2 ) within the rhizosphere. Following this, % MeHg in sediment (0-5cm) within the meadow was approximately 10× higher compared to outside the meadow. Further, enhanced availability of MeHg within the meadow was demonstrated by significantly higher fluxes (p<0.01) from sediment to overlying water (0.1-0.6ngm -2 d -1 ) compared to sediment without macrophytes (0.02-0.2ngm -2 d -1 ). Considering the productivity and species richness typical for such habitats, submerged macrophyte meadows located within legacy Hg contaminated sediment sites may constitute important entry points for MeHg into food webs. Copyright © 2017 Elsevier B.V. All rights reserved.

Microbial and biochemical alterations due to storage of deep-sea sediments under ambient tropical conditions

Digital Repository Service at National Institute of Oceanography (India)

Das, A.; Fernandes, C.E.G.; Naik, S.S.; Mourya, B.S.; Sujith, P.P.; Sharma, R; LokaBharathi, P.A.

-tight polythene containers. Changes in microbial and biochemical parameters were monitored once in every two months for a year. Bacterial counts and ATP decreased from ~108 to ~107 g-1 and ~103 to ~101 ng g-1 dry sediment respectively, within 8-10 months before...

Assessment of heavy metals pollution using AVS-SEM and fractionation techniques in Edku Lagoon sediments, Mediterranean Sea, Egypt.

Science.gov (United States)

El Zokm, Gehan M; Okbah, Mohamed A; Younis, Alaa M

2015-01-01

A method is presented to evaluate the fractionation of metals (Fe, Zn, Cu, Pb, Cd and Ni), acid volatile sulfide (AVS) and simultaneously extracted metals (SEM) in Edku lagoon sediments. Thirteen sediment samples were collected from the study area in the period of 2010-2011 to assess the potential bioavailability and toxicity of the selected metals. According to classification of the Interim Sediment Quality Quidelines (ISQG), five stations near the drains exhibited 10% toxic probability. The high AVS and low ∑SEM ranges in Summer were identified as 6-138 and 0.86-3.3 µmol g(-1) dry wet, respectively which are referring to the low mobility of heavy metals in this season and vice versa for winter (2.5-23.9 and 1.16-3.82 µmol g(-1) dry wet, respectively). According to the evaluation of USEPA, all sediment samples showed ∑SEM/AVS heavy metals in Edku lagoon sediments posed a low risk of adverse biological effects due to cadmium, copper, lead, nickel and zinc in all evaluated stations.

Chemical speciation and transformation of mercury in contaminated sediments

OpenAIRE

Drott, Andreas

2009-01-01

Biomagnification of mercury (Hg) in aquatic food webs occurs almost exclusively as mono-methyl Hg (MeHg). In this thesis, the influence of chemical speciation and environmental conditions on transformations of inorganic Hg (HgII) and MeHg was studied at eight sites in Sweden with Hg contaminated sediments. The source of contamination was either Hg0(l) or phenyl-Hg, and total Hg concentrations ranged between 1.0-1100 nmol g-1. The environmental conditions, e.g. salinity, temperature climate, p...

OSL dating of fine-grained quartz from Holocene Yangtze delta sediments

DEFF Research Database (Denmark)

Sugisaki, Saiko; Buylaert, Jan-Pieter; Murray, Andrew

2015-01-01

Holocene flood events in the Yangtze River are associated with variations in East Asian Summer Monsoon (EASM) precipitation, and so Yangtze delta sediments may preserve information about the frequency and magnitude of EASM precipitation. These flood/drought cycles of the EASM directly affect...... the living standards of East Asian population. However, despite its importance, little chronological control is available for the Yangtze Delta sediments; because biogenic carbonate only occurs sporadically, it has proved the difficulty to discuss sedimentation mechanisms and rates in any detail. In 2013 two...... sediment cores (YD13-G3 and H1) were taken from the Yangtze subaqueous delta to investigate precipitation history. In this study, we investigate the potential of quartz OSL dating of the fine silt fraction (fine-grained quartz; 4-11 μm) from these cores to estimate the depositional age of the sediments. We...

Sediment-water distribution of perfluorooctane sulfonate (PFOS) in Yangtze River Estuary

International Nuclear Information System (INIS)

Pan Gang; You Chun

2010-01-01

Analysis of Perfluorooctane sulfonate (PFOS) distribution in water and sediment in Yangtze River Estuary showed that the estuary was a sink for PFOS. Salinity was an important parameter in controlling the sediment-water interactions and the fate or transport of PFOS in the aquatic environment. As the salinity (S per mille ) increased from 0.18 to 3.31, the distribution coefficient (K d ) between sediment and water linearly increased from 0.76 to 4.70 L g -1 . The study suggests that PFOS may be carried with the river water and transported for long distances before it reaches to the sea and largely scavenged to the sediment in the estuaries due to the dramatic change in salinity. - PFOS may be largely scavenged to the sediment in estuaries due to the dramatic change in salinity during its transport from lands to oceans.

Lower concentrations of blueberry polyphenolic-rich extract differentially alter HepG2 cell proliferation and expression of genes related to cell-cycle, oxidation and epigenetic machinery

Science.gov (United States)

In vitro cancer models have been used to study the effect of relatively high concentrations (>200 ug/ml) of phenolic plant extracts upon cell proliferation. In this study we report that the treatment of human hepatocarcinoma HepG2 cells with lower concentrations of blueberry phenolic extract (6.5-10...

Biofilms' contribution to organic carbon in salt marsh sediments

Science.gov (United States)

Valentine, K.; Quirk, T. E.; Mariotti, G.; Hotard, A.

2017-12-01

Coastal salt marshes are productive environments with high potential for carbon (C) accumulation. Organic C in salt marsh sediment is typically attributed to plant biomass. Recent field measurements, however, suggest that biofilms - mainly composed of benthic diatoms and their secretion - also contribute to basal C in these environments and can be important contributors to marsh productivity, C cycling, and potentially, C sequestration. The potential for biofilms to soil organic C and the influence of mineral sedimentation of biofilm-based C accumulation is unknown. We conducted controlled laboratory experiments to test (1) whether biofilms add measurable amounts of organic C to the sediment and (2) the effect of mineral sedimentation rate on the amount of biofilm-based C accumulation. Settled beds of pure bentonite mud were created in 10-cm-wide cylinders. Each cylinder was inoculated with biofilms collected from a marsh in Louisiana. A small amount of mud was added weekly for 11 weeks. Control experiments without biofilms were also performed. Biofilms were grown with a 12/12 hours cycle, with a gentle mixing of the water column that did not cause sediment resuspension, with a nutrient-rich medium that was exchanged weekly, and in the absence of metazoan grazing. At the end of the experiment, the sediment columns were analyzed for depth-integrated chl-a, loss on ignition (LOI), and total organic carbon (TOC). Chl-a values ranged from 26-113 mg/cm2, LOI values ranged from 86-456 g/m2/yr, and TOC values ranged from 31-211 g/m2/yr. All three of these metrics (chl-a, LOI, and TOC) increased with the rate of mineral sedimentation. These results show that biofilms, in the absence of erosion and grazing, can significantly contribute to C accumulation in salt marshes, especially with high rates of mineral sedimentation. Given the short time scale of the experiment, the increase in organic C accumulation with the rate of sedimentation is attributed to stimulated biofilm

The H,G_1,G_2 photometric system with scarce observational data

Science.gov (United States)

Penttilä, A.; Granvik, M.; Muinonen, K.; Wilkman, O.

2014-07-01

The H,G_1,G_2 photometric system was officially adopted at the IAU General Assembly in Beijing, 2012. The system replaced the H,G system from 1985. The 'photometric system' is a parametrized model V(α; params) for the magnitude-phase relation of small Solar System bodies, and the main purpose is to predict the magnitude at backscattering, H := V(0°), i.e., the (absolute) magnitude of the object. The original H,G system was designed using the best available data in 1985, but since then new observations have been made showing certain features, especially near backscattering, to which the H,G function has troubles adjusting to. The H,G_1,G_2 system was developed especially to address these issues [1]. With a sufficient number of high-accuracy observations and with a wide phase-angle coverage, the H,G_1,G_2 system performs well. However, with scarce low-accuracy data the system has troubles producing a reliable fit, as would any other three-parameter nonlinear function. Therefore, simultaneously with the H,G_1,G_2 system, a two-parameter version of the model, the H,G_{12} system, was introduced [1]. The two-parameter version ties the parameters G_1,G_2 into a single parameter G_{12} by a linear relation, and still uses the H,G_1,G_2 system in the background. This version dramatically improves the possibility to receive a reliable phase-curve fit to scarce data. The amount of observed small bodies is increasing all the time, and so is the need to produce estimates for the absolute magnitude/diameter/albedo and other size/composition related parameters. The lack of small-phase-angle observations is especially topical for near-Earth objects (NEOs). With these, even the two- parameter version faces problems. The previous procedure with the H,G system in such circumstances has been that the G-parameter has been fixed to some constant value, thus only fitting a single-parameter function. In conclusion, there is a definitive need for a reliable procedure to produce

LC-H-1 NMR used for determination of the elution order of S-naproxen glucuronide isomers in two isocratic reversed-phase LC-systems

DEFF Research Database (Denmark)

Mortensen, R. W.; Corcoran, O.; Cornett, Claus

2001-01-01

. In both systems the elution order for the 2-, 3- and 4-O-acyl isomers corresponded with previously published results for 2-, 3-, and 4-fluorobenzoic acid glucuronide isomers determined by reversed phase HPLC-H-1 NMR [U.G. Sidelmann, S.H. Hansen, C. Gavaghan, A.W. Nicholls, H.A.J. Carless, J.C. Lindon, I...

Incidência de fumonisina B1, aflatoxinas B1, B2, G1 e G2, ocratoxina A e zearalenona em produtos de milho Occurrence of fumonisin B1, aflatoxins B1, B2, G1, and G2, ochratoxin A and zearalenone in corn products

Directory of Open Access Journals (Sweden)

Luciane Mie Kawashima

2006-09-01

Full Text Available Levantamentos de ocorrência de micotoxinas em alimentos foram realizados nas últimas duas décadas nas regiões Sudeste e Sul do Brasil. Levantamentos em alimentos comercializados em outras regiões têm-se limitado a aflatoxinas em amendoim e castanhas do Brasil. O presente trabalho pesquisou a presença de fumonisina B1, aflatoxinas B1, B2, G1 e G2, ocratoxina A e zearalenona em 74 amostras de produtos a base de milho adquiridas no comércio da cidade de Recife, PE, durante o período de 1999 a 2001. Fumonisina B1 foi determinada por cromatografia líquida de alta eficiência com detecção por fluorescência e as demais toxinas foram determinadas por cromatografia em camada delgada. Fumonisina B1 foi encontrada em 94,6% das amostras em concentrações variando de 20 a 8600 µg/kg. Apenas 5 amostras continham aflatoxina B1 e o teor máximo encontrado foi 20 µg/kg. Duas amostras ultrapassaram o limite de 20 µg/kg para a somatória das aflatoxinas B1, B2, G1 e G2 (farinha de milho pré-cozida com 21,5 µg/kg e quirera (xerém com 23,3 µg/kg. As aflatoxinas G1 e G2, ocratoxina A e zearalenona não foram detectadas em nenhuma das amostras. Todas as amostras contaminadas com aflatoxinas também apresentaram fumonisina B1.Research concerning the presence of mycotoxin in food has been conducted in the Southwest and South regions of Brazil over the last two decades. Research in other regions has been limited to aflatoxin in peanuts and Brazil nuts. The aim of this work is to study the presence of fumonisin B1, aflatoxins B1, B2, G1, and G2, ochratoxin A and zearalenone in 74 samples of corn products acquired in shops and food markets in the city of Recife (PE from 1999 to 2001. Fumonisin B1 was determined by high performance liquid chromatography and fluorescence was detected. The other toxins were determined by thin layer chromatography. Fumonisin B1 was found in 94.6% of the samples in levels from 20 to 8600 µg/kg. Only 5 samples contained

Geochemical distribution of polycyclic aromatic hydrocarbons in soils and sediments of El-Tabbin, Egypt.

Science.gov (United States)

Havelcová, Martina; Melegy, Ahmed; Rapant, Stanislav

2014-01-01

Polycyclic aromatic hydrocarbons (PAHs) were extracted from 30 samples (24 soils and 6 stream sediments) collected in El-Tabbin area in the southern part of Greater Cairo, Egypt. Isopleth maps of PAHs clarified the regional variability and identified the most affected regions in the area suffering from high pollution. The total PAH concentrations were 53.4-5558.0 ng g(-1) in the sample extracts. The highest values were found in a soil sample near a coke factory, with the highest concentration of single PAHs, which were 1064.8 ng g(-1) of fluoranthene and 1286.4 ng g(-1) of phenanthrene. The calculated ratios and indexes allowed to elucidate origin of the organic compounds and to identify emission sources. The overall molecular patterns are signatures of pyrolysis of fossil fuels and biomass. Petrogenic contamination was recognised in the sediment samples due to petroleum products deliveries from ships. Also perylene was prominent especially in samples of the River Nile sediments as a diagenetic product of fungi. Other detailed information on petrogenic sources was provided by analysis of alkanes and calculation of alkane ratios. Copyright © 2013 Elsevier Ltd. All rights reserved.

Structural practices for controlling sediment transport from erosion

Science.gov (United States)

Gabriels, Donald; Verbist, Koen; Van de Linden, Bruno

2013-04-01

Erosion on agricultural fields in the hilly regions of Flanders, Belgium has been recognized as an important economical and ecological problem that requires effective control measures. This has led to the implementation of on-site and off-site measures such as reduced tillage and the installation of grass buffers trips, and dams made of vegetative materials. Dams made out of coir (coconut) and wood chips were evaluated on three different levels of complexity. Under laboratory conditions, one meter long dams were submitted to two different discharges and three sediment concentrations under two different slopes, to assess the sediment delivery ratios under variable conditions. At the field scale, discharge and sediment concentrations were monitored under natural rainfall conditions on six 3 m wide plots, of which three were equipped with coir dams, while the other three served as control plots. The same plots were also used for rainfall simulations, which allowed controlling sediment delivery boundary conditions more precisely. Results show a clear advantage of these dams to reduce discharge by minimum 49% under both field and laboratory conditions. Sediment delivery ratios (SDR) were very small under laboratory and field rainfall simulations (4-9% and 2% respectively), while larger SDRs were observed under natural conditions (43%), probably due to the small sediment concentrations (1-5 g l-1) observed and as such a larger influence of boundary effects. Also a clear enrichment of larger sand particles (+167%) could be observed behind the dams, showing a significant selective filtering effect.

Modified finite element transport model, FETRA, for sediment and radionuclide migration in open coastal waters

International Nuclear Information System (INIS)

Onishi, Y.; Arnold, E.M.; Mayer, D.W.

1979-08-01

The finite element model, FETRA, simulates transport of sediment and radionuclides (and other contaminants, such as heavy metals, pesticides, and other toxic substances) in surface water bodies. The model is an unsteady, two-dimensional (longitudinal and lateral) model which consists of the following three submodels coupled to include sediment-contaminant interactions: (1) sediment transport submodel, (2) dissolved contaminant transport submodel, and (3) particulate contaminant (contaminant adsorbed by sediment) transport submodel. Under the current phase of the study, FETRA was modified to include sediment-wave interaction in order to extend the applicability of the model to coastal zones and large lakes (e.g., the Great Lakes) where wave actions can be one of the dominant mechanisms to transport sediment and toxic contaminant. FETRA was further modified to handle both linear and quadratic approximations to velocity and depth distributions in order to be compatible with various finite element hydrodynamic models (e.g., RMA II and CAFE) which supply hydrodynamic input data to FETRA. The next step is to apply FETRA to coastal zones to simulate transport of sediment and radionuclides with their interactions in order to test and verify the model under marine and large lacustrine environments

Sediments of a retting yard

Digital Repository Service at National Institute of Oceanography (India)

Remani, K.N.; Venugopal, P.; Devi, K.S.; Unnithan, R.V.

(av. 46.8 and 92.3 mg/g respectively) compared to the reference station (20.6 and 48.9 mg/g) and published data on estuarine sediments.C/N ratios were consistently higher in the retting yard. Organic nitrogen, however,did not show this trend. Annual...

An examination of historic inorganic sedimentation and organic matter accumulation in several marsh types within the Mobile Bay and and Mobile-Tensaw River Delta region

Science.gov (United States)

Smith, Christopher G.; Osterman, Lisa E.; Poore, Richard Z.

2013-01-01

Mass accumulation rates (MAR; g cm-2 y-1), linear sedimentation rates (LSR; cm y-1), and core geochronology derived from excess lead-210 (210Pb) profiles and inventories measured in six sediment cores collected from marsh sites from the MobileTensaw River Delta and Mobile Bay region record the importance of both continuous and event-driven inorganic sedimentation over the last 120 years. MAR in freshwater marshes varied considerably between sites and through time (0.24 and 1.31 g cm-2 y-1). The highest MARs occurred in the 1950s and 1960s and correspond to record discharge events along the Mobile and Tensaw Rivers. In comparison, MAR at salt marsh sites increased almost threefold over the last 120 years (0.05 to 0.18 g cm-2 y-1 or 0.23 to 0.48 cm y-1). From 1880 to 1960, organic accumulation remained fairly constant (20%), while intermittent pulses of high inorganic sedimentation were observed following 1960. The pulses in inorganic sedimentation coincide with several major hurricanes (e.g., Hurricanes Camille, Fredric, Georges, and Ivan). The nearly threefold increase in MAR in salt marshes during the last 120 years would thus appear to be partially dependent on inorganic sedimentation from storm events. This study shows that while hurricanes, floods, and other natural hazards are well-known threats to human infrastructure and coastal ecosystems, these events also transport sediment to marshes that help abate other pressures such as sea-level rise (SLR) and subsidence.

PAI-1 4G/5G polymorphism contributes to cancer susceptibility: evidence from meta-analysis.

Science.gov (United States)

Wang, Shangqian; Cao, Qiang; Wang, Xiaoxiang; Li, Bingjie; Tang, Min; Yuan, Wanqing; Fang, Jianzheng; Qian, Jian; Qin, Chao; Zhang, Wei

2013-01-01

The plasminogen activator inhibitor-1 (PAI-1) is expressed in many cancer cell types and allows the modulation of cancer growth, invasion and angiogenesis. To date, studies investigated the association between a functional polymorphism in PAI-1 (4G/5G) and risk of cancer have shown inclusive results. A meta-analysis based on 25 case-control studies was performed to address this issue. Odds ratios (OR) with corresponding 95% confidence intervals (CIs) were used to assess the association. The statistical heterogeneity across studies was examined with I(2) test. Overall, a significant increased risk of cancer was associated with the PAI-1 4G/4G polymorphism for the allele contrast (4G vs. 5G: OR = 1.10, CI = 1.03-1.18, I(2) = 49.5%), the additive genetic model (4G/4G vs. 5G/5G: OR = 1.21, CI = 1.06-1.39, I(2) = 51.9%), the recessive genetic model (4G/4G vs. 4G/5G+5G/5G: OR = 1.11, CI = 1.04-1.18, I(2) = 20.8%). In the subgroup analysis by ethnicity, the results indicated that individuals with 4G/4G genotype had a significantly higher cancer risk among Caucasians (4G/4G vs. 5G/5G: OR = 1.31, 95%CI = 1.09-1.59, I(2) = 59.6%; 4G/4G vs. 4G/5G: OR = 1.12, 95%CI = 1.04-1.21, I(2) = 3.6%; recessive model: OR = 1.12, 95%CI = 1.05-1.21, I(2) = 25.3%). The results of the present meta-analysis support an association between the PAI-1 4G/5G polymorphism and increasing cancer risk, especially among Caucasians, and those with 4G allele have a high risk to develop colorectal cancer and endometrial cancer.

Flame retardants, surfactants and organotins in sediment and mysid shrimp of the Scheldt estuary (The Netherlands)

International Nuclear Information System (INIS)

Verslycke, Tim A.; Vethaak, A. Dick; Arijs, Katrien; Janssen, Colin R.

2005-01-01

Sediment and mysids from the Scheldt estuary, one of the largest and most polluted estuaries in Western Europe, were analyzed for a number of contaminants that have been shown to possess endocrine-disrupting activity, i.e. organotins, polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBPA), nonylphenol ethoxylates (NPE) and transformation products, nonylphenol (NP) and nonylphenol ether carboxylates (NPEC). In addition, in vitro estrogenic and androgenic potencies of water and sediment extracts were determined. Total organotin concentrations ranged from 84 to 348 ng/g dw in sediment and 1110 to 1370 ng/g dw in mysid. Total PBDE (excluding BDE-209) concentrations ranged from 14 to 22 ng/g dw in sediment and from 1765 to 2962 ng/g lipid in mysid. High concentrations of BDE-209 (240-1650 ng/g dw) were detected in sediment and mysid (269-600 ng/g lipid). Total HBCD concentrations in sediment and mysid were 14-71 ng/g dw and 562-727 ng/g lipid, respectively. Total NPE concentrations in sediment were 1422 ng/g dw, 1222 ng/g dw for NP and 80 ng/g dw for NPEC and ranged from 430 to 1119 ng/g dw for total NPE and from 206 to 435 ng/g dw for NP in mysid. Significant estrogenic potency, as analyzed using the yeast estrogen assay, was detected in sediment and water samples from the Scheldt estuary, but no androgenic activity was found. This study is the first to report high levels of endocrine disruptors in estuarine mysids. - Field populations of mysid shrimp (Neomysis integer) of the Scheldt estuary (The Netherlands) are exposed to high concentrations of endocrine disruptors

Life cycle assessment for dredged sediment placement strategies.

Science.gov (United States)

Bates, Matthew E; Fox-Lent, Cate; Seymour, Linda; Wender, Ben A; Linkov, Igor

2015-04-01