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Результаты 141-150 из 775
VOC in an urban and industrial harbor on the French North Sea coast during two contrasted meteorological situations
2009
Roukos, Joelle | Riffault, Véronique | Locoge, Nadine | Plaisance, Hervé
Two measurement campaigns of volatile organic compounds (VOC) were carried out in the industrial city of Dunkerque, using Radiello passive samplers during winter (16-23 January) and summer (6-13 June) 2007. 174 compounds were identified belonging to six chemical families. Classifying sampling sites with similar chemical profiles by hierarchical ascending classification resulted in 4 groups that reflected the influence of the main industrial and urban sources of pollution. Also, the BTEX (Benzene, Toluene, Ethylbenzene and Xylenes) quantification allowed us to map their levels of concentration. Benzene and toluene (BT) showed high concentrations in Northern Dunkerque reflecting the influence of two industrial plants. Differences among spatial distributions of the BT concentrations over contrasted meteorological conditions were also observed. An atypical ratio of T/B in the summer samples led us to investigate the BTEX origins shedding light on the contribution of pollutants transported across various zones of VOC emissions situated in Europe. This study was devoted for screening of VOC and investigation of local and regional source contributions to BTEX concentration in a French industrialized harbor.
Показать больше [+] Меньше [-]Polycyclic aromatic hydrocarbon (PAH) contamination of surface sediments and oysters from the inter-tidal areas of Dar es Salaam, Tanzania
2009
Gaspare, Lydia | Machiwa, John F. | Mdachi, S.J.M. | Streck, Georg | Brack, Werner
Surface sediment and oyster samples from the inter-tidal areas of Dar es Salaam were analyzed for 23 polycyclic aromatic hydrocarbons (PAHs) including the 16 compounds prioritized by US-EPA using GC/MS. The total concentration of PAHs in the sediment ranged from 78 to 25,000 ng/g dry weight, while oyster concentrations ranged from 170 to 650 ng/g dry weight. Hazards due to sediment contamination were assessed using Equilibrium Partitioning Sediment Benchmarks and Threshold Effect Levels. Diagnostic indices and principle component analysis were used to identify possible sources. Interestingly, no correlation between sediment and oyster concentrations at the same sites was found. This is supported by completely different contamination patterns, suggesting different sources for both matrices. Hazard assessment revealed possible effects at six out of eight sites on the benthic communities and oyster populations. The contribution of PAH intake via oyster consumption to carcinogenic risks in humans seems to be low. PAH contamination may pose hazards to benthos but limited risks to humans
Показать больше [+] Меньше [-]Occurrence and effects of tire wear particles in the environment - A critical review and an initial risk assessment
2009
Wik, Anna | Dave, Göran
This review summarizes the existing knowledge on the occurrence of tire wear particles in the environment, and their ecotoxicological effects. A meta-analysis on tire components in the environment revealed that tire wear particles are present in all environmental compartments, including air, water, soils/sediments, and biota. The maximum Predicted Environmental Concentrations (PECs) of tire wear particles in surface waters range from 0.03 to 56 mg l-1 and the maximum PECs in sediments range from 0.3 to 155 g kg-1 d.w. The results from our previous long-term studies with Ceriodaphnia dubia and Pseudokirchneriella subcapitata were used to derive Predicted No Effect Concentrations (PNECs). The upper ranges for PEC/PNEC ratios in water and sediment were >1, meaning that tire wear particles present potential risks for aquatic organisms. We suggest that management should be directed towards development and production of more environmentally friendly tires and improved road runoff treatment.
Показать больше [+] Меньше [-]Residential runoff as a source of pyrethroid pesticides to urban creeks
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.
Показать больше [+] Меньше [-]The growth response of Alternanthera philoxeroides in a simulated post-combustion emission with ultrahigh [CO2] and acidic pollutants
2009
Xu, Cheng-Yuan | Griffin, Kevin L. | Blazier, John C. | Craig, Elizabeth C. | Gilbert, Dominique S. | Sritrairat, Sanpisa | Anderson, O Roger | Castaldi, Marco J. | Beaumont, E. Larry
Although post-combustion emissions from power plants are a major source of air pollution, they contain excess CO₂ that could be used to fertilize commercial greenhouses and stimulate plant growth. We addressed the combined effects of ultrahigh [CO₂] and acidic pollutants in flue gas on the growth of Alternanthera philoxeroides. When acidic pollutants were excluded, the biomass yield of A. philoxeroides saturated near 2000 μmol mol⁻¹ [CO₂] with doubled biomass accumulation relative to the ambient control. The growth enhancement was maintained at 5000 μmol mol⁻¹ [CO₂], but declined when [CO₂ rose above 1%, in association with a strong photosynthetic inhibition. Although acidic components (SO₂ and NO₂) significantly offset the CO2 enhancement, the aboveground yield increased considerably when the concentration of pollutants was moderate (200 times dilution). Our results indicate that using excess CO₂ from the power plant emissions to optimize growth in commercial green house could be viable. Diluted post-combustion emission gas from fossil fuel fired power plants stimulate the growth of C₃ plant.
Показать больше [+] Меньше [-]Glutathione transferase (GST) as a candidate molecular-based biomarker for soil toxin exposure in the earthworm Lumbricus rubellus
2009
LaCourse, E James | Hernandez-Viadel, Mariluz | Jefferies, James R. | Svendsen, Claus | Spurgeon, David J. | Barrett, John | Morgan, A John | Kille, Peter | Brophy, Peter M.
The earthworm Lumbricus rubellus (Hoffmeister, 1843) is a terrestrial pollution sentinel. Enzyme activity and transcription of phase II detoxification superfamily glutathione transferases (GST) is known to respond in earthworms after soil toxin exposure, suggesting GST as a candidate molecular-based pollution biomarker. This study combined sub-proteomics, bioinformatics and biochemical assay to characterise the L. rubellus GST complement as pre-requisite to initialise assessment of the applicability of GST as a biomarker. L. rubellus possesses a range of GSTs related to known classes, with evidence of tissue-specific synthesis. Two affinity-purified GSTs dominating GST protein synthesis (Sigma and Pi class) were cloned, expressed and characterised for enzyme activity with various substrates. Electrospray ionisation mass spectrometry (ESI-MS) and tandem mass spectrometry (MS/MS) following SDS-PAGE were superior in retaining subunit stability relative to two-dimensional gel electrophoresis (2-DE). This study provides greater understanding of Phase II detoxification GST superfamily status of an important environmental pollution sentinel organism. This study currently provides the most comprehensive view of the Phase II detoxification enzyme superfamily of glutathione transferases within the important environmental pollution sentinel earthworm Lumbricus rubellus.
Показать больше [+] Меньше [-]Long-term air monitoring of organochlorine pesticides using Semi Permeable Membrane Devices (SPMDs) in the Alps
2009
Levy, W. | Henkelmann, B. | Pfister, G. | Bernhöft, S. | Kirchner, M. | Jakobi, G. | Bassan, R. | Kräuchi, N. | Schramm, K.W.
Atmospheric sampling of organochlorine pesticides (OCPs) was conducted using Semi Permeable Membrane Devices (SPMDs) deployed in the Alps at different altitudinal transects for two consecutive exposure periods of half a year and a third simultaneous year-long period. Along all the altitude profiles, the sequestered amounts of OCPs increased in general with altitude. SPMDs were still working as kinetic samplers after half a year for the majority of the OCPs. However, compounds with the lowest octanol-air partition coefficient (Koa), reached equilibrium within six months. This change in the SPMD uptake was determined for the temperature gradient along the altitude profile influencing Koa, OCPs availability in the gaseous phase, and SPMD performance. In sum, it seems two effects are working in parallel along the altitude profiles: the change in SPMD performance and the different availability of OCPs along the altitudinal transects determined by their compound properties and concentrations in air. SPMDs were in different uptake stages regarding OCPs, as they were influenced by the temperature (season, triolein state, and altitude) and Koa.
Показать больше [+] Меньше [-]Organochlorine pesticide air-water exchange and bioconcentration in krill in the Ross Sea
2009
Cincinelli, Alessandra | Martellini, Tania | Del Bubba, Massimo | Lepri, Luciano | Corsolini, Simonetta | Borghesi, Nicoletta | King, Martin D. | Dickhut, Rebecca M.
Mean hexachlorobenzene (HCB) and hexachlorocyclohexane (HCH) concentrations, measured in seawater and air samples, confirmed the decline in levels of these compounds in Antarctic air and water. However, low α/γ-HCH ratios in air at the beginning of the sampling period suggest a predominance of fresh lindane entering the Antarctic atmosphere during the Austral spring probably due to current use in the Southern Hemisphere. Water-air fugacity ratios demonstrate the potential for HCH gas deposition to coastal Antarctic seas, while the water-air fugacity ratios for HCB imply that volatilization does not account for the observed decrease of HCB in surface seawater. HCH concentrations found in krill samples were correlated with seawater concentrations indicative of bioconcentration of HCHs from seawater. Hexachlorocyclohexanes (HCHs) continue to decline in Antarctic air, but fugacity ratios demonstrate that Antarctic coastal waters remain a sink for HCHs, which bioconcentrate in krill via direct uptake from water.
Показать больше [+] Меньше [-]Expression of alkane monooxygenase (alkB) genes by plant-associated bacteria in the rhizosphere and endosphere of Italian ryegrass (Lolium multiflorum L.) grown in diesel contaminated soil
2009
Andria, Verania | Reichenauer, Thomas G. | Sessitsch, Angela
For phytoremediation of organic contaminants, plants have to host an efficiently degrading microflora. To assess the role of endophytes in alkane degradation, Italian ryegrass was grown in sterile soil with 0, 1 or 2% diesel and inoculated either with an alkane degrading bacterial strain originally derived from the rhizosphere of Italian ryegrass or with an endophyte. We studied plant colonization of these strains as well as the abundance and expression of alkane monooxygenase (alkB) genes in the rhizosphere, shoot and root interior. Results showed that the endophyte strain better colonized the plant, particularly the plant interior, and also showed higher expression of alkB genes suggesting a more efficient degradation of the pollutant. Furthermore, plants inoculated with the endophyte were better able to grow in the presence of diesel. The rhizosphere strain colonized primarily the rhizosphere and showed low alkB gene expression in the plant interior. Bacterial alkane degradation genes are expressed in the rhizosphere and in the plant interior.
Показать больше [+] Меньше [-]Genotoxicity of water from the Songhua River, China, in 1994-1995 and 2002-2003: Potential risks for human health
2009
Liu, Jia-Ren | Dong, Hong-Wei | Tang, Xuan-Le | Sun, Xiang-Rong | Han, Xiao-Hui | Chen, Bing-Qing | Sun, Chang-Hao | Yang, Bao-Feng
A previous study showed that the cancer mortalities are higher for residents who lived nearby the Songhua River heavily polluted by organic contamination. It is important to determine its risk of carcinogenic potential. Short-term genotoxic bio-assays using Salmonella, Sister Chromatid Exchange (SCE), and Micronuclei (MN) assays were employed to examine the genotoxic activity of ether extracts of water samples taken from the Songhua River. The results of the Salmonella bioassay indicated that there were indirect frame-shift mutagens in the water samples. A dose-response relationship for the SCE and MN assays was obtained. These results showed that organic extracts of water samples have genotoxic activity and the risk of carcinogenic potential to human health. The mutagenesis of water samples had changed compared to the results in 1994-1995. An increasing trend of risk of carcinogenic potential in the Songhua River after ten years should be noted and needs to be studied further.
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