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Arsenic mobility in brownfield soils amended with green waste compost or biochar and planted with Miscanthus Texte intégral
2009
Hartley, William | Dickinson, Nicholas M. | Riby, Philip | Lepp, N. W. (Nicholas W)
Degraded land that is historically contaminated from different sources of industrial waste provides an opportunity for conversion to bioenergy fuel production and also to increase sequestration of carbon in soil through organic amendments. In pot experiments, As mobility was investigated in three different brownfield soils amended with green waste compost (GWC, 30% v/v) or biochar (BC, 20% v/v), planted with Miscanthus. Using GWC improved crop yield but had little effect on foliar As uptake, although the proportion of As transferred from roots to foliage differed considerably between the three soils. It also increased dissolved carbon concentrations in soil pore water that influenced Fe and As mobility. Effects of BC were less pronounced, but the impacts of both amendments on SOC, Fe, P and pH are likely to be critical in the context of As leaching to ground water. Growing Miscanthus had no measurable effect on As mobility. Green waste compost enhances water-soluble iron, phosphorus and carbon, increasing arsenic mobility in soil pore water.
Afficher plus [+] Moins [-]Mitigation of two pyrethroid insecticides in a Mississippi Delta constructed wetland Texte intégral
2009
Moore, M.T. | Cooper, C.M. | Smith, S. Jr | Cullum, R.F. | Knight, S.S. | Locke, M.A. | Bennett, E.R.
Constructed wetlands are a suggested best management practice to help mitigate agricultural runoff before entering receiving aquatic ecosystems. A constructed wetland system (180 m x 30 m), comprising a sediment retention basin and two treatment cells, was used to determine the fate and transport of simulated runoff containing the pyrethroid insecticides lambda-cyhalothrin and cyfluthrin, as well as suspended sediment. Wetland water, sediment, and plant samples were collected spatially and temporally over 55 d. Results showed 49 and 76% of the study's measured lambda-cyhalothrin and cyfluthrin masses were associated with vegetation, respectively. Based on conservative effects concentrations for invertebrates and regression analyses of maximum observed wetland aqueous concentrations, a wetland length of 215 m x 30 m width would be required to adequately mitigate 1% pesticide runoff from a 14 ha contributing area. Results of this experiment can be used to model future design specifications for constructed wetland mitigation of pyrethroid insecticides. A wetland length of 215 m x 30 m mitigated pyrethroid runoff from a 14 ha field.
Afficher plus [+] Moins [-]Long-term trends in mercury and PCB congener concentrations in gannet (Morus bassanus) eggs in Britain Texte intégral
2009
Pereira, M Glória | Walker, Lee A. | Best, Jennifer | Shore, Richard F.
Gannet (Morus bassanus) eggs from Bass Rock (North Sea) and Ailsa Craig (eastern Atlantic) were monitored for PCB congeners (1990-2004) and total mercury (1974-2004). Congener profiles for both colonies were dominated by PCBs 153, 138, 180, 118 and 170. All declined in concentration at Ailsa Craig but some (153, 170, 180) remained stable or increased slightly at Bass Rock. Egg congener concentrations at Bass Rock were typically 10-fold higher than at Ailsa Craig by 2002, and Principal Component Analysis indicated that colony differences were driven by the dominant congeners. Egg mercury concentrations were significantly lower at Bass Rock than at Ailsa Craig and temporal trends differed, there being a significant decline at Ailsa Craig but a marginal increase at Bass Rock. Our results suggest there may be differences in contamination between the eastern Atlantic and North Sea and/or there are colony differences in prey selection and associated contaminant loads. Monitoring of PCBs and Hg in gannet eggs reveals contrasting temporal patterns between colonies on the eastern Atlantic and North Sea coasts of Britain.
Afficher plus [+] Moins [-]Pteris vittata - Revisited: Uptake of As and its speciation, impact of P, role of phytochelatins and S Texte intégral
2009
Vetterlein, Doris | Wesenberg, Dirk | Nathan, Petra | Bräutigam, Anja | Schierhorn, Angelika | Mattusch, Jürgen | Jahn, Reinhold
Pteris vittata is known to hyperaccumulate As but the mechanism is poorly understood. We found an increase of As concentration with increasing soil solution As concentrations, but P application had no impact, although plant P concentrations responded to different rates of P supply. As in fronds was dominantly (82-89%) present in the form of AsIII. In roots we detected 45% as AsIII which is higher than reported in previous studies and supports substantial As-reduction to take place in roots. We detected PC2/3GS-AsIII, PC2-GS-AsIII and (PC2)2-AsIII in increasing amounts with application of As. The total amount of PC was in the range reported previously and far too small to assign a significant role in As detoxification to PCs. The close correlation between S and As in fronds and the lack of data on sulphur uptake and metabolism indicates the need for a detailed investigation on sulphur nutritional status and As metabolism in P. vittata. As-PC complexes were detected in increasing amounts with increasing As availability, but total amounts were small and do not explain the close correlation between S and As in fronds.
Afficher plus [+] Moins [-]Assessment of human health risk related to metals by the use of biomonitors in the province of Córdoba, Argentina Texte intégral
2009
Carreras, Hebe A. | Wannaz, Eduardo D. | Pignata, María L.
The evaluation of metal contents in the environment is of vital importance for the assessment of human exposure. Thus the species Usnea amblyoclada, Ramalina celastri and Tillandsia capillaris were tested as bioaccumulators of transition metals in the urban area of Córdoba city, Argentina. The level of metals on biomonitors was compared to that of total deposition samples. All three species discriminated zones within the urban area of Córdoba city with different pollution levels; they revealed high levels of Zn in the downtown area and confirmed high levels of some transition metals in an industrial area. The correlation analysis revealed that the lichen R. celastri had the highest correlation rates with total deposition samples, suggesting it is a valuable biomonitor of atmospheric pollution. A significant relationship was also observed between respiratory diseases in children and the contents of metal accumulated in R. celastri and T. capillaris, indicating their usefulness when assessing human exposure to metals. Metal accumulation in epiphytes is correlated with human respiratory diseases.
Afficher plus [+] Moins [-]Bioaccumulation of glyphosate and its formulation Roundup Ultra in Lumbriculus variegatus and its effects on biotransformation and antioxidant enzymes Texte intégral
2009
Contardo-Jara, Valeska | Klingelmann, Eva | Wiegand, Claudia
The bioaccumulation potential of glyphosate and the formulation Roundup Ultra, as well as possible effects on biotransformation and antioxidant enzymes in Lumbriculus variegatus were compared by four days exposure to concentrations between 0.05 and 5 mg L-1 pure glyphosate and its formulation. Bioaccumulation was determined using 14C labeled glyphosate. The bioaccumulation factor (BCF) varied between 1.4 and 5.9 for the different concentrations, and was higher than estimated from log Pow. Glyphosate and its surfactant POEA caused elevation of biotransformation enzyme soluble glutathione S-transferase at non-toxic concentrations. Membrane bound glutathione S-transferase activity was significantly elevated in Roundup Ultra exposed worms, compared to treatment with equal glyphosate concentrations, but did not significantly differ from the control. Antioxidant enzyme superoxide dismutase was significantly increased by glyphosate but in particular by Roundup Ultra exposure indicating oxidative stress. The results show that the formulation Roundup Ultra is of more ecotoxicological relevance than the glyphosate itself. Roundup Ultra is of more ecotoxicological relevance than the active ingredient, glyphosate, to Lumbriculus variegatus regarding accumulation potential and enzymatic responses.
Afficher plus [+] Moins [-]Residential runoff as a source of pyrethroid pesticides to urban creeks Texte intégral
2009
Weston, D.P. | Holmes, R.W. | Lydy, M.J.
Pyrethroid pesticides occur in urban creek sediments at concentrations acutely toxic to sensitive aquatic life. To better understand the source of these residues, runoff from residential neighborhoods around Sacramento, California was monitored over the course of a year. Pyrethroids were present in every sample. Bifenthrin, found at up to 73 ng/L in the water and 1211 ng/g on suspended sediment, was the pyrethroid of greatest toxicological concern, with cypermethrin and cyfluthrin of secondary concern. The bifenthrin could have originated either from use by consumers or professional pest controllers, though the seasonal pattern of discharge from the drain was more consistent with professional use as the dominant source. Stormwater runoff was more important than dry season irrigation runoff in transporting pyrethroids to urban creeks. A single intense storm was capable of discharging as much bifenthrin to an urban creek in 3 h as that discharged over 6 months of irrigation runoff. Pyrethroid insecticides regularly detected in residential runoff at toxicologically significant concentrations.
Afficher plus [+] Moins [-]Regional trends in soil acidification and exchangeable metal concentrations in relation to acid deposition rates Texte intégral
2009
Stevens, Carly J. | Dise, Nancy B. | Gowing, David J.
The deposition of high levels of reactive nitrogen (N) and sulphur (S), or the legacy of that deposition, remain among the world's most important environmental problems. Although regional impacts of acid deposition in aquatic ecosystems have been well documented, quantitative evidence of wide-scale impacts on terrestrial ecosystems is not common. In this study we analysed surface and subsoil chemistry of 68 acid grassland sites across the UK along a gradient of acid deposition, and statistically related the concentrations of exchangeable soil metals (1 M KCl extraction) to a range of potential drivers. The deposition of N, S or acid deposition was the primary correlate for 8 of 13 exchangeable metals measured in the topsoil and 5 of 14 exchangeable metals in the subsoil. In particular, exchangeable aluminium and lead both show increased levels above a soil pH threshold of about 4.5, strongly related to the deposition flux of acid compounds. S and N deposition contribute to regional-scale soil acidification and metal mobilisation.
Afficher plus [+] Moins [-]Herbicides: A new threat to the Great Barrier Reef Texte intégral
2009
Lewis, Stephen E. | Brodie, J. E. (Jon E) | Bainbridge, Zoë T. | Rohde, Ken W. | Davis, Aaron M. | Masters, Bronwyn L. | Maughan, Mirjam | Devlin, Michelle J. | Mueller, Jochen F. | Schaffelke, Britta
The runoff of pesticides (insecticides, herbicides and fungicides) from agricultural lands is a key concern for the health of the iconic Great Barrier Reef, Australia. Relatively low levels of herbicide residues can reduce the productivity of marine plants and corals. However, the risk of these residues to Great Barrier Reef ecosystems has been poorly quantified due to a lack of large-scale datasets. Here we present results of a study tracing pesticide residues from rivers and creeks in three catchment regions to the adjacent marine environment. Several pesticides (mainly herbicides) were detected in both freshwater and coastal marine waters and were attributed to specific land uses in the catchment. Elevated herbicide concentrations were particularly associated with sugar cane cultivation in the adjacent catchment. We demonstrate that herbicides reach the Great Barrier Reef lagoon and may disturb sensitive marine ecosystems already affected by other pressures such as climate change. Herbicide residues have been detected in Great Barrier Reef catchment waterways and river water plumes which may affect marine ecosystems.
Afficher plus [+] Moins [-]Ozone exposure of field-grown winter wheat affects soil mesofauna in the rhizosphere Texte intégral
2009
Schrader, Stefan | Bender, Jürgen | Weigel, Hans-Joachim
Ozone exposure of field-grown winter wheat affects soil mesofauna in the rhizosphere Texte intégral
2009
Schrader, Stefan | Bender, Jürgen | Weigel, Hans-Joachim
A 2-year open-top chamber experiment with field-grown winter wheat (Triticum aestivum L. cv. Astron) was conducted to examine the effects of ozone on plant growth and selected groups of soil mesofauna in the rhizosphere. From May through June in each year, plants were exposed to two levels of O3: non-filtered (NF) ambient air or NF+ 40 ppb O3 (NF+). During O3 exposure, soil sampling was performed at two dates according to different plant growth stages. O3 exposure reduced above- and below-ground plant biomass in the first year, but had little effect in the second year. The individual density of enchytraeids, collembolans and soil mites decreased significantly in the rhizosphere of plants exposed to NF+ in both years. Differences were highest around anthesis, i.e. when plants are physiologically most active. The results suggest that elevated O3 concentrations may influence the dynamic of decomposition processes and the turnover of nutrients. Ozone reduced the individual densities of enchytraeids, collembolans and soil mites in the rhizosphere of winter wheat indirectly via the plant–soil-system.
Afficher plus [+] Moins [-]Ozone exposure of field-grown winter wheat affects soil mesofauna in the rhizosphere Texte intégral
2009
Schrader, Stefan | Bender, Jürgen | Weigel, Hans-Joachim
A 2-year open-top chamber experiment with field-grown winter wheat (Triticum aestivum L. cv. Astron) was conducted to examine the effects of ozone on plant growth and selected groups of soil mesofauna in the rhizosphere. From May through June in each year, plants were exposed to two levels of O3: nonfiltered (NF) ambient air or NFþ 40 ppb O3 (NFþ). During O3 exposure, soil sampling was performed at two dates according to different plant growth stages. O3 exposure reduced above- and below-ground plant biomass in the first year, but had little effect in the second year. The individual density of enchytraeids, collembolans and soil mites decreased significantly in the rhizosphere of plants exposed to NF+ in both years. Differences were highest around anthesis, i.e. when plants are physiologically most active. The results suggest that elevated O3 concentrations may influence the dynamic of decomposition processes and the turnover of nutrients.
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