| 1. |
- Lemieux, Christine, et al.
(författare)
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Mutagenic Hazards of Complex Polycyclic Aromatic Hydrocarbon Mixtures in Contaminated Soil
- 2008
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Ingår i: Environmental Toxicology and Chemistry. - : Society of Environmental Toxicology and Chemistry (SETAC). - 0730-7268 .- 1552-8618. ; 27:4, s. 978-990
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to evaluate hazard/risk assessment methods for complex environmental mixtures that involve a targeted, priority chemical approach based on the cumulative hazard/risk of known mixture components or analyses of sufficiently similar mixtures. Ten polycyclic aromatic hydrocarbon (PAH)-contaminated soils were separated into non-polar and semi-polar fractions, and both fractions elicited positive responses on the Salmonella reverse mutation assay. Targeted and non-targeted methods of hazard prediction routinely provided overestimations of observed mutagenic activities for the non-polar soil fractions, suggesting non-additive interactions of PAHs in complex mixtures. This suggests that current risk assessment methods for complex mixtures may provide conservative estimates for soils contaminated with priority PAHs alone. However, significant underestimations of total risk will be obtained if the soils also contain unidentified PAHs, as well as polycyclic aromatic compounds (PACs) and related compounds that contribute to the total mutagenic activity. Furthermore, estimates of excess lifetime cancer risk associated with the non-dietary ingestion of the PAH-contaminated soils studied here indicate that a traditional risk assessment model based on identified priority PAHs and an assumption of additivity, generally provides an underestimate of the risk associated with the non-polar soil fractions (in comparison with bioassay-derived risk estimates). Additional cancer risk may be associated with the more polar compounds that are also found at these contaminated sites, and that are rarely included in the standard risk assessment methodology.
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| 2. |
- Trindade, Mirta, et al.
(författare)
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Enzyme-Linked Immunosorbent Assay for Screening Dioxin Soil Contamination by Uncontrolled Combustion During Informal Recycling in Slums
- 2008
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Ingår i: Environmental Toxicology and Chemistry. - : John Wiley & Sons. - 0730-7268 .- 1552-8618. ; 27:11, s. 2224-2232
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Tidskriftsartikel (refereegranskat)abstract
- Uncontrolled combustion due to garbage recycling is a widespread activity among slum dwellers in distressed economy countries, and has been indicated as a major source of dioxin contamination. However, due to the high cost and complexity of gas chromatography-high resolution mass spectrometry (GC-HRMS) analysis, the magnitude of the problem remains largely unknown. This work describes a first approach towards the use of a dioxin antibody-based enzyme-linked immunosorbent assay (ELISA) as the basis for a sustainable, simple, and low cost monitoring program to assess the toxicological impact of uncontrolled combustion in slums. A panel of sixteen samples was analyzed by GC-HRMS and ELISA on split extracts. Close to 20 % of the analyzed samples showed dioxin concentrations up to almost twice the guidance level for residential soil in several countries, pointing out the need for performing a large-scale monitoring program. Despite the potential for variations in dioxin congener distribution due to the mixed nature of the incinerated material, there was a good correlation between the toxic equivalents as determined by GC-HRMS and ELISA. Furthermore, an inter-laboratory ELISA validation showed that the capacity to perform the dioxin ELISA was successfully transferred between laboratories. It was concluded that the ELISA method performed very well as a screening tool to prioritize samples for instrumental analysis, which allows cutting down costs significantly.
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| 3. |
- Törneman, Niklas, et al.
(författare)
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Spatial covariation of microbial community composition and polycyclic aromatic hydrocarbon concentration in a creosote-polluted soil
- 2008
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 27:5, s. 1039-1046
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Tidskriftsartikel (refereegranskat)abstract
- Little is known about the spatial connection between soil microbial community composition and polycyclic aromatic hydrocarbon (PAH) concentration. A spatially explicit survey at a creosote-contaminated site demonstrated that microbial biomass (total concentration of phospholipid fatty acids [PLFAs]) and microbial community composition (PLFA fingerprints) were spatially autocorrelated, mostly within a distance of 25 m, and covaried with PAH concentrations. The concentration of PLFAs indicative of gram-negative bacteria (16:1 omega 7c, 16:1 omega 7t, 18:1 omega 7, cy17:0, and cy19:0) increased in the PAH hot spots, whereas PLFAs representing fungi and gram-positive bacteria (including actinomycetes) were negatively correlated to PAH concentrations. Most PLFAs were spatially autocorrelated, with distances varying between 4 and 25 m. Those PLFAs that increased in PAH-contaminated soil had autocorrelation ranges between 4 and 16 m, whereas the fungal indicator PLEA 18:2 omega 6,9 had the largest autocorrelation range (25 in). Bacterial strains isolated using a spray-plate technique and with the same PLFA composition as that in contaminated soil samples were capable of degrading phenanthrene, fluoranthene, and pyrene, indicating that the main PAH degraders could be isolated.
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| 4. |
- Aldén, Louise, et al.
(författare)
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Use of pollution-induced community tolerance of the bacterial community to detect phenol toxicity in soil.
- 2008
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Ingår i: Environmental Toxicology and Chemistry. - 0730-7268. ; 27:2, s. 334-340
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Tidskriftsartikel (refereegranskat)abstract
- Pollution-induced community tolerance (PICT) was used to study effects of phenol on soil bacteria. Phenol was added to an agricultural soil in a microcosm experiment. The effects were studied for up to four months. Bacterial growth rates were estimated with the leucine incorporation technique. This technique was also used as detection method for PICT. Changes in community structure were studied using the phospholipid fatty acid (PLFA) pattern. Increased phenol PICT of the bacterial community was found at phenol concentrations above 1 micromol/g wet weight soil. Direct inhibiting effect on bacterial growth rates 1 d after adding phenol was correlated to PICT. Phenol toxicity was reflected by changes in the structure of the bacterial community, although PICT appeared more sensitive than the PLFA method. In soil amended with 1 to 10 micromol phenol/g soil, bacterial growth recovered within one week. In the soil amended with the highest phenol concentration (30 micromol/g soil), bacterial growth rate recovered from total inhibition after 27 d, eventually reaching values six times higher than in the control. However, PICT did not change during the four months the experiment was performed. The specificity of PICT was also studied by examining cotolerance to 2-chlorophenol, 2,4-dichlorophenol, 2,3,6-trichlorophenol, Cu, and Zn. Adding phenol induced cotolerance of the bacterial community to the other phenols, although always at a lover level than to phenol. No cotolerance was found to metals in phenol-polluted soil. We conclude that the PICT concept is a valuable tool in determining phenol toxicity to bacterial communities, especially in situations where bacterial growth has recovered. Cotolerance between different phenols can, however, make interpretations of PICT more complicated.
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