خيارات البحث
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Prenatal methylmercury exposure through maternal rice ingestion: Insights from a feasibility pilot in Guizhou Province, China
2013
Rothenberg, Sarah E. | Yu, Xiaodan | Zhang, Yumei
Maternal hair and blood were investigated as biomarkers for prenatal methylmercury (MeHg) exposure among seventeen mothers recruited at parturition in Wanshan, Guizhou Province, China, where rice ingestion was the primary MeHg exposure pathway and atmospheric mercury (Hg) levels were elevated. For all three trimesters (n = 51), hair total Hg (THg) and MeHg concentrations ranged from 0.27 to 4.9 μg/g (median: 0.96 μg/g) and 0.077 to 2.3 μg/g (median: 0.43 μg/g), respectively, while blood THg levels ranged from 1.7 to 11 μg/L (median: 3.0 μg/L, n = 17). Despite adequate hair washing procedures, median %MeHg (of THg) was 37% (range: 14–89%, n = 51), indicating exogenous inorganic Hg(II) contamination or incorporation of elemental Hg (Hgo) into the hair shaft were important. Rice MeHg levels (n = 17) were highly correlated with blood THg (r2 = 0.66) compared to hair MeHg (r2 = 0.31) (when variables were log10-transformed), suggesting blood THg was a more preferable biomarker for prenatal MeHg exposure within this population.
اظهر المزيد [+] اقل [-]Bioremediation of benzene-, MTBE- and ammonia-contaminated groundwater with pilot-scale constructed wetlands
2011
Seeger, Eva M. | Kuschk, Peter | Fazekas, Helga | Grathwohl, Peter | Kaestner, Matthias
In this pilot-scale constructed wetland (CW) study for treating groundwater contaminated with benzene, MTBE, and ammonia-N, the performance of two types of CWs (a wetland with gravel matrix and a plant root mat) was investigated. Hypothesized stimulative effects of filter material additives (charcoal, iron(III)) on pollutant removal were also tested. Increased contaminant loss was found during summer; the best treatment performance was achieved by the plant root mat. Concentration decrease in the planted gravel filter/plant root mat, respectively, amounted to 81/99% for benzene, 17/82% for MTBE, and 54/41% for ammonia-N at calculated inflow loads of 525/603 mg/m²/d, 97/112 mg/m²/d, and 1167/1342 mg/m²/d for benzene, MTBE, and ammonia-N. Filter additives did not improve contaminant depletion, although sorption processes were observed and elevated iron(II) formation indicated iron reduction. Bacterial and stable isotope analysis provided evidence for microbial benzene degradation in the CW, emphasizing the promising potential of this treatment technique.
اظهر المزيد [+] اقل [-]Application of bioassays to evaluate a copper contaminated soil before and after a pilot-scale electrokinetic remediation
2009
Wang, Quan-Ying | Zhou, Dong-Mei | Cang, Long | Sun, Tian-Ran
Remediation programmes are considered to be complete when human risk-based criteria are met. However, these targets are often unsatisfied with the ecological parameters that may be important with regard to future soil use. Five soil subsamples, collecting along a pilot-scale soil column after electrokinetic treatment, were studied, from which about 42.0%-93.3% soil Cu had been successfully removed. A series of biological assays including soil microbial biomass carbon, basal soil respiration, soil urease activity, earthworm assays, and seed assays were used to evaluate their ecological risks. The results showed that the bioassay data from the treatment variants did not supposedly reflecting the decreased soil Cu concentrations after the electrokinetic treatment, but were highly correlated with some soil physicochemical characteristics. It suggests that bioassays are necessary to assess the ecotoxicity of soil after electrokinetic treatment.
اظهر المزيد [+] اقل [-]Occurrence and persistence of organic emerging contaminants and priority pollutants in five sewage treatment plants of Spain: Two years pilot survey monitoring
2012
Bueno, M.J Martínez | Gomez, M.J. | Herrera, S. | Hernando, M.D. | Agüera, A. | Fernández-Alba, A.R.
This work summarized all results obtained during almost two-years of a monitoring programme carried out in five municipal sewage treatment plants (STPs) located in the north, centre and south-east of Spain. The study evaluated the occurrence and persistence of a group of 100 organic compounds belonging to several chemical groups (pharmaceuticals, personal care products, pesticides and metabolites). The average removal efficiencies of the STPs studied varied from 20% (erythromycin) to 99% (acetaminophen). In analysed samples, we identified a large number of compounds at mean range concentrations between 7–59,495 ng/L and 5–32,720 ng/L for influent and effluent samples, respectively. This study also identified 20 of the mostly detected and persistent compounds in wastewater effluent, of which hydrochlorothiazide, atenolol, gemfibrozil, galaxolide and three metabolites (fenofibric acid, 4-AAA and 4-FAA), presented the highest average contribution percentages, in relation to the total load of contaminants for the different STPs effluent studied.
اظهر المزيد [+] اقل [-][Technology project: Interaction of plants and microorganisms in elimination of organic soil pollutants]
2000
Karlson, U.
[Technology project: Soil washing: A method for remediation of contaminated soil]
2000
Oemig, F. | Lindskov, C. | Joergensen, E.K.
[Technology project: Phytoremediation of metals: pilot project]
2000
Andersen, L. | Holm, P.E. | Joergensen, U. | Bruun, P.