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Widespread waterborne pollution in central Swedish lakes and the Baltic Sea from pre-industrial mining and metallurgy Texto completo
2009
Bindler, Richard | Renberg, Ingemar | Rydberg, Johan | Andrén, Thomas
Metal pollution is viewed as a modern problem that began in the 19th century and accelerated through the 20th century; however, in many parts of the globe this view is wrong. Here, we studied past waterborne metal pollution in lake sediments from the Bergslagen region in central Sweden, one of many historically important mining regions in Europe. With a focus on lead (including isotopes), we trace mining impacts from a local scale, through a 120-km-long river system draining into Mälaren - Sweden's third largest lake, and finally also the Baltic Sea. Comparison of sediment and peat records shows that pollution from Swedish mining was largely waterborne and that atmospheric deposition was dominated by long-range transport from other regions. Swedish ore lead is detectable from the 10th century, but the greatest impact occurred during the 16th-18th centuries with improvements occurring over recent centuries, i.e., historical pollution > modern industrial pollution. Pollution in Sweden during AD 900-1900 was often greater than modern industrial pollution.
Mostrar más [+] Menos [-]Effects of chemical oxidation on sorption and desorption of PAHs in typical Chinese soils Texto completo
2009
Chen, Wei | Hou, Lei | Sitong. | Zhu, Lingyan
In situ chemical oxidation is a commonly applied soil and groundwater remediation technology, but can have significant effects on soil properties, which in turn might affect fate and transport of organic contaminants. In this study, it was found that oxidation treatment resulted mainly in breakdown of soil organic matter (SOM) components. Sorption of naphthalene and phenanthrene to the original soils and the KMnO₄-treated soils was linear, indicating that hydrophobic partitioning to SOM was the predominant mechanism for sorption. Desorption from the original and treated soils was highly resistant, and was well modeled with a biphasic desorption model. Desorption of residual naphthalene after treating naphthalene-contaminated soils with different doses of KMnO4 also followed the biphasic desorption model very well. It appears that neither changes of soil properties caused by chemical oxidation nor direct chemical oxidation of contaminated soils had a noticeable effect on the nature of PAH-SOM interactions. Chemical oxidation of soils had little effect on the mechanisms controlling sorption and desorption of PAHs.
Mostrar más [+] Menos [-]Degradation of a chiral nonylphenol isomer in two agricultural soils Texto completo
2009
Zhang, Haifeng | Spiteller, M (Michael) | Guenther, Klaus | Boehmler, Gabriele | Zuehlke, Sebastian
The degradation of a chiral nonylphenol isomer, 4-(1-ethyl-1,4-dimethylpentyl)phenol (NP₁₁₂), in two agricultural soils from Monheim and Dortmund, Germany has been studied. The degradation of NP₁₁₂ and the formation of a nitro-nonylphenol metabolite were determined by means of GC-MS analysis. The degradation followed bi-exponential order kinetics, with half-life of less than 5 days in both soils. The nitro-metabolite was found at different concentration levels in the two soils. The nitro-metabolite of NP₁₁₂ was more persistent than its parent compound. After 150 days about 13% of the initially applied NP₁₁₂ remained in the Monheim soil as its nitro-metabolite. Results of the E-screen assay revealed that the nitro-NP₁₁₂ has oestrogenic potency of 85% of that of NP₁₁₂. Furthermore, the results of chiral GC-MS analysis revealed that no chiral degradation of NP₁₁₂ occurred in this study. The degradation of a chiral nonylphenol isomer in agricultural soils followed bi-exponential order kinetics resulting in a more persistent nitro-metabolite.
Mostrar más [+] Menos [-]Sorption behavior of bensulfuron-methyl on andisols and ultisols volcanic ash-derived soils: Contribution of humic fractions and mineral–organic complexes Texto completo
2009
Espinoza, Jeannette | Fuentes, Edwar | Báez, Maria E.
Bensulfuron-methyl sorption was studied in Andisol and Ultisol soils in view of their characteristic physical and chemical properties, presenting acidic pH and variable charge. Humic and fulvic acids (HA and FA) and humin (HUM) contributions were established. Sorption was studied by using two synthetic sorbents, an aluminum-silicate with iron oxide coverage and the same sorbent coated with humic acid. Freundlich model described Bensulfuron-methyl behavior in all sorbents (R2 0.969–0.998). Kf for soils (8.3–20.7 μg1−1/n mL1/n g−1) were higher than those reported in the literature. Organic matter, halloysite or kaolinite, and specific surface area contributed to the global process. The highest Kf for HA, FA and HUM were 539.5, 82.9, and 98.7 μg1−1/n mL1/n g−1. Model sorbents described the participation of variable charge materials with high adsorption capacity. The constant capacitance model was used to assess effects of Bensulfuron-methyl adsorption on the distribution of SOH, SOH2+ and SO− sites of sorbents. Organic matter, phyllosilicates, variable charge minerals and organo-mineral complexes contribute to bensulfuron-methyl sorption on volcanic ash-derived soils.
Mostrar más [+] Menos [-]Predicting bioremediation of hydrocarbons: Laboratory to field scale Texto completo
2009
Diplock, E.E. | Mardlin, D.P. | Killham, K.S. | Paton, G.I.
There are strong drivers to increasingly adopt bioremediation as an effective technique for risk reduction of hydrocarbon impacted soils. Researchers often rely solely on chemical data to assess bioremediation efficiently, without making use of the numerous biological techniques for assessing microbial performance. Where used, laboratory experiments must be effectively extrapolated to the field scale. The aim of this research was to test laboratory derived data and move to the field scale. In this research, the remediation of over thirty hydrocarbon sites was studied in the laboratory using a range of analytical techniques. At elevated concentrations, the rate of degradation was best described by respiration and the total hydrocarbon concentration in soil. The number of bacterial degraders and heterotrophs as well as quantification of the bioavailable fraction allowed an estimation of how bioremediation would progress. The response of microbial biosensors proved a useful predictor of bioremediation in the absence of other microbial data. Field-scale trials on average took three times as long to reach the same endpoint as the laboratory trial. It is essential that practitioners justify the nature and frequency of sampling when managing remediation projects and estimations can be made using laboratory derived data. The value of bioremediation will be realised when those that practice the technology can offer transparent lines of evidence to explain their decisions. Detailed biological, chemical and physical characterisation reduces uncertainty in predicting bioremediation.
Mostrar más [+] Menos [-]Copper availability and bioavailability are controlled by rhizosphere pH in rape grown in an acidic Cu-contaminated soil Texto completo
2009
Chaignon, Valérie | Quesnoit, Marie | Hinsinger, Philippe
Copper availability and bioavailability are controlled by rhizosphere pH in rape grown in an acidic Cu-contaminated soil Texto completo
2009
Chaignon, Valérie | Quesnoit, Marie | Hinsinger, Philippe
We evaluated how root-induced changes in rhizosphere pH varied and interacted with Cu availability and bioavailability in an acidic soil. Rape was grown on a Cu-contaminated acidic soil, which had been limed at 10 rates. Soil Cu bioavailability was not influenced by liming. However, liming significantly decreased CaCl2–extracted Cu for pH between 3.7 and 5.1. Little effect was found for pH above 5.1. For soil pH < 4.4, CaCl2–Cu contents were smaller in rhizosphere than uncropped soil. Rhizosphere alkalisation occurred at pH < 4.8, while acidification occurred at greater pH. This explained the changes of CaCl2–Cu in the rhizosphere at low pH and the absence of pH dependency of Cu bioavailability to rape. In addition, apoplastic Cu in roots increased with increasing soil pH, most probably as a result of increased dissociation and affinity of cell wall compounds for Cu. Root-induced increase in pH reduces Cu availability in the rhizosphere and Cu bioavailability to rape.
Mostrar más [+] Menos [-]Copper availability and bioavailability are controlled by rhizosphere pH in rape grown in an acidic Cu-contaminated soil Texto completo
2009
Chaignon, Valérie | Quesnoit, Marie | Hinsinger, Philippe | Ecologie Fonctionnelle et Biogéochimie des Sols (Eco&Sols) ; Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Ecole Nationale Supérieure Agronomique de Montpellier (ENSA M)
Correspondance auteur: P. Hinsinger e-mail: [email protected] | International audience | We evaluated how root-induced changes in rhizosphere pH varied and interacted with Cu availability and bioavailability in an acidic soil. Rape was grown on a Cu-contaminated acidic soil, which had been limed at 10 rates. Soil Cu bioavailability was not influenced by liming. However, liming significantly decreased CaCl2-extracted Cu for pH between 3.7 and 5.1. Little effect was found for pH above 5.1. For soil pH < 4.4, CaCl2-Cu contents were smaller in rhizosphere than uncropped soil. Rhizosphere alkalisation occurred at pH < 4.8, while acidification occurred at greater pH. This explained the changes of CaCl2-Cu in the rhizosphere at low pH and the absence of pH dependency of Cu bioavailability to rape. In addition, apoplastic Cu in roots increased with increasing soil pH, most probably as a result of increased dissociation and affinity of cell wall compounds for Cu
Mostrar más [+] Menos [-]A coupled simulation-optimization approach for groundwater remediation design under uncertainty: An application to a petroleum-contaminated site Texto completo
2009
He, L. | Huang, G.H. | Lu, H.W.
This study provides a coupled simulation-optimization approach for optimal design of petroleum-contaminated groundwater remediation under uncertainty. Compared to the previous approaches, it has the advantages of: (1) addressing the stochasticity of the modeling parameters in simulating the flow and transport of NAPLs in groundwater, (2) providing a direct and response-rapid bridge between remediation strategies (pumping rates) and remediation performance (contaminant concentrations) through the created proxy models, (3) alleviating the computational cost in searching for optimal solutions, and (4) giving confidence levels for the obtained optimal remediation strategies. The approach is applied to a practical site in Canada for demonstrating its performance. The results show that mitigating the effects of uncertainty on optimal remediation strategies (through enhancing the confidence level) would lead to the rise of remediation cost due to the increase in the total pumping rate. This study provides a coupled simulation-optimization approach for optimal design of groundwater remediation under uncertainty.
Mostrar más [+] Menos [-]Gaseous mercury emissions from unsterilized and sterilized soils: The effect of temperature and UV radiation Texto completo
2009
Choi, Hyun-Deok | Holsen, Thomas M.
Mercury (Hg) emissions from the soils taken from two different sites (deciduous and coniferous forests) in the Adirondacks were measured in outdoor and laboratory experiments. Some of the soil samples were irradiated to eliminate biological activity. The result from the outdoor measurements with different soils suggests the Hg emission from the soils is partly limited by fallen leaves covering the soils which helps maintain relatively high soil moisture and limits the amount of heat and solar radiation reaching the soil surface. In laboratory experiments exposure to UV-A (365 nm) had no significant effect on the Hg emissions while the Hg emissions increased dramatically during exposure to UV-B (302 nm) light suggesting UV-B directly reduced soil-associated Hg. Overall these results indicate that for these soils biotic processes have a relatively constant and smaller influence on the Hg emission from the soil than the more variable abiotic processes. Hg emission measurements from soils indicate that abiotic processes were more important than biotic processes in reducing Hg and controlling emissions.
Mostrar más [+] Menos [-]Ozone exposure of field-grown winter wheat affects soil mesofauna in the rhizosphere Texto completo
2009
Schrader, Stefan | Bender, Jürgen | Weigel, Hans-Joachim
Ozone exposure of field-grown winter wheat affects soil mesofauna in the rhizosphere Texto completo
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.
Mostrar más [+] Menos [-]Ozone exposure of field-grown winter wheat affects soil mesofauna in the rhizosphere Texto completo
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.
Mostrar más [+] Menos [-]Regional trends in soil acidification and exchangeable metal concentrations in relation to acid deposition rates Texto completo
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.
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