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Factors influencing aquatic-to-terrestrial contaminant transport to terrestrial arthropod consumers in a multiuse river system Texte intégral
2016
Alberts, Jeremy M. | Sullivan, Mažeika
Emerging aquatic insects are important vectors of contaminant transfer from aquatic to terrestrial food webs. However, the environmental factors that regulate contaminant body burdens in nearshore terrestrial consumers remain largely unexplored. We investigated the relative influences of riparian landscape composition (i.e., land use and nearshore vegetation structure) and contaminant flux via the emergent aquatic insect subsidy on selenium (Se) and mercury (Hg) body burdens of riparian ants (Formica subsericea) and spiders of the family Tetragnathidae along 11 river reaches spanning an urban-rural land-use gradient in Ohio, USA. Model-selection results indicated that fine-scale land cover (e.g., riparian zone width, shrub cover) in the riparian zone was positively associated with reach-wide body burdens of Se and Hg in both riparian F. subsericea and tetragnathid spiders (i.e., total magnitude of Hg and Se concentrations in ant and spider populations, respectively, for each reach). River distance downstream of Columbus, Ohio – where study reaches were impounded and flow through a large urban center – was also implicated as an important factor. Although stable-isotope analysis suggested that emergent aquatic insects were likely vectors of Se and Hg to tetragnathid spiders (but not to F. subsericea), emergent insect contaminant flux did not emerge as a significant predictor for either reach-wide body burdens of spider Hg or Se. Improved understanding of the pathways and influences that control aquatic-to-terrestrial contaminant transport will be critical for effective risk management and remediation.
Afficher plus [+] Moins [-]Exposure to pyrethroid pesticides and the risk of childhood brain tumors in East China Texte intégral
2016
Chen, Sheng | Gu, Shuo | Wang, Yue | Yao, Yongliang | Wang, Guoquan | Jin, Yue | Wu, Yeming
Pesticide exposure is hypothesized as one of the risk factors for the development of childhood brain tumors (CBT). This hospital-based case–control study evaluated the association of pyrethroid pesticide exposure with the risk for CBT in a children population in East China. In total, 161 CBT cases and 170 controls were recruited from 2 children's medical centers in Shanghai (Xinhua Hospital and Shanghai Children's Medical Center) between September 2012 and June 2015. The cases and controls were matched for age, sex, and province of residence. Pyrethroid pesticide exposure was evaluated by urinalysis of 3 nonspecific metabolites of pyrethroids (cis-DCCA, trans-DCCA, and 3-PBA) using gas chromatography-mass spectrometry (GC-MS) detection and by administering a questionnaire. Unconditional logistic regression showed that trans-DCCA, 3-PBA, and total metabolites (sum of the 3 metabolites) were positively associated with the increased risk of CBT. Children in the highest quartile had a nearly 3-fold increased risk of CBT compared with those in the lowest quartile after adjusting for confounding factors (trans-DCCA, odds ratio (OR) = 2.58, 95% confidence interval (CI), 1.38–4.80, p = 0.003; 3-PBA, OR = 3.26, 95% CI, 1.73–6.14, p < 0.0001; total metabolites, OR = 3.60, 95% CI, 1.87–6.93, p < 0.0001). We also found that exposure to both mosquitocide and cockroach killer was related to the increased risk of CBT (mosquitocide, OR = 1.68, 95% CI, 1.06–2.67, p = 0.027; cockroach killer, OR = 1.83, 95% CI, 1.13–2.95, p = 0.013). These findings indicate that exposure to pyrethroid pesticides might be associated with increased risk of CBT. Prospective cohort studies with larger sample sizes are required to confirm this conclusion.
Afficher plus [+] Moins [-]Mercury remediation in wetland sediment using zero-valent iron and granular activated carbon Texte intégral
2016
Lewis, Ariel S. | Huntington, Thomas G. | Marvin-DiPasquale, Mark C. | Amirbahman, Aria
Wetlands are hotspots for production of toxic methylmercury (MeHg) that can bioaccumulate in the food web. The objective of this study was to determine whether the application of zero-valent iron (ZVI) or granular activated carbon (GAC) to wetland sediment could reduce MeHg production and bioavailability to benthic organisms. Field mesocosms were installed in a wetland fringing Hodgdon Pond (Maine, USA), and ZVI and GAC were applied. Pore-water MeHg concentrations were lower in treated compared with untreated mesocosms; however, sediment MeHg, as well as total Hg (THg), concentrations were not significantly different between treated and untreated mesocosms, suggesting that smaller pore-water MeHg concentrations in treated sediment were likely due to adsorption to ZVI and GAC, rather than inhibition of MeHg production. In laboratory experiments with intact vegetated sediment clumps, amendments did not significantly change sediment THg and MeHg concentrations; however, the mean pore-water MeHg and MeHg:THg ratios were lower in the amended sediment than the control. In the laboratory microcosms, snails (Lymnaea stagnalis) accumulated less MeHg in sediment treated with ZVI or GAC. The study results suggest that both GAC and ZVI have potential for reducing MeHg bioaccumulation in wetland sediment.
Afficher plus [+] Moins [-]Mercury risk assessment combining internal and external exposure methods for a population living near a municipal solid waste incinerator Texte intégral
2016
Deng, Chunyan | Xie, Han | Ye, Xuejie | Zhang, Haoran | Liu, Maodian | Tong, Yindong | Ou, Langbo | Yuan, Wen | Zhang, Wei | Wang, Xuejun
Risk assessments for human health have been conducted for municipal solid waste incinerators (MSWIs) in many western countries, whereas only a few risk assessments have been performed for MSWIs in developing countries such as China where the use of waste incineration is increasing rapidly. To assess the mercury exposure risks of a population living near the largest MSWI in South China, we combined internal exposure and external exposure assessment with an individual–specific questionnaire. The mercury concentrations in air, soil, and locally collected food around the MSWI were assessed. The total mercury (T-Hg) and methylmercury (MeHg) of 447 blood samples from a control group, residential exposure group, and MSWI workers were measured. The internal and external exposures of the subject population were analyzed. Significant difference in MeHg concentrations was observed between the control group and the exposed group, between the control group and the MSWI workers, and between the exposed group and the MSWI workers (median levels: 0.70 μg/L, 0.81 μg/L, and 1.02 μg/L for the control group, exposed group, and MSWI workers, respectively). The MeHg/T-Hg ratio was 0.51 ± 0.19, 0.59 ± 0.17 and 0.58 ± 0.25, respectively. Multiple linear regression analysis indicated that MeHg concentrations were positively correlated with the gaseous mercury in the air. Combining internal and external exposure assessment showed that the direct contribution of MSWI emissions was minor compared with the dietary contribution. The external and internal exposures were well matched with each other. This study also suggested that an integrated method combining internal and external exposure assessment with an individual–specific questionnaire is feasible to assess the risks for a population living near a MSWI.
Afficher plus [+] Moins [-]Palaeo-pollution from mining activities in the Vosges Mountains: 1000 years and still bioavailable Texte intégral
2016
Mariet, Anne-Lise | de Vaufleury, Annette | Bégeot, Carole | Walter-Simonnet, Anne-Véronique | Gimbert, Frédéric
Palaeo-pollution from mining activities in the Vosges Mountains: 1000 years and still bioavailable Texte intégral
2016
Mariet, Anne-Lise | de Vaufleury, Annette | Bégeot, Carole | Walter-Simonnet, Anne-Véronique | Gimbert, Frédéric
Mining and smelting activities have contaminated the environment with trace metals (TMs) at a worldwide scale for at least two millennia. A combination of chemical approaches and active biomonitoring was performed to analyse the environmental availability and bioavailability of TM palaeo-pollution in a former PbAg mining district in the Vosges Mountains, France. Along a soil TM contamination gradient that covered eight stations, including two archaeological mining sites, the toxicokinetics of six TMs (Pb, Cd, As, Ag, Co, Sb) in the snail Cantareus aspersus revealed that palaeo-pollution from the studied sites remains bioavailable. This study provides the first data on the accumulation kinetics of Ag and Co for C. aspersus. The environmental availability of the TMs was estimated with three chemical extraction methods (aqua regia, EDTA 50 mM, CaCl2 10 mM). Univariate regression analyses showed that EDTA extraction is the best method for estimating the bioavailability of Pb, As, Ag, Co and Sb to snails. None of the three extractants was efficient for Cd. A multivariate analysis of bioaccumulation data revealed that TM bioavailability and transfer were modulated by exposure sources (soil, humus and vegetation) rather than by soil physico-chemical characteristics. Hence, although the deposition of mining wastes dates back several centuries, these wastes still represent a source of contamination that must be considered to develop relevant site management and environmental risk assessment.
Afficher plus [+] Moins [-]Palaeo-pollution from mining activities in the Vosges Mountains: 1000 years and still bioavailable Texte intégral
2016
Mariet, Anne-Lise | de Vaufleury, Annette | Bégeot, Carole | Walter-Simonnet, Anne-Véronique | Gimbert, Frédéric | Université Bourgogne Franche-Comté [COMUE] (UBFC) | Funding Agency and Grant Number : French "Agence de l'Environnement et de la Maitrise de l'Energie" (ADEME); Conseil Regional de Franche-Comte; University of Franche-Comte (BQR PRES); French national program EC2CO-Ecodyn (POLMIN); University of Bourgogne (BQR PRES)
International audience | Mining and smelting activities have contaminated the environment with trace metals (TMs) at a worldwide scale for at least two millennia. A combination of chemical approaches and active biomonitoring was performed to analyse the environmental availability and bioavailability of TM palaeo-pollution in a former Pb-Ag mining district in the Vosges Mountains, France. Along a soil TM contamination gradient that covered eight stations, including two archaeological mining sites, the toxicokinetics of six TMs (Pb, Cd, As, Ag, Co, Sb) in the snail Cantareus aspersus revealed that palaeo-pollution from the studied sites remains bioavailable. This study provides the first data on the accumulation kinetics of Ag and Co for C. aspersus. The environmental availability of the TMs was estimated with three chemical extraction methods (aqua regia, EDTA 50 mM, CaCl2 10 mM). Univariate regression analyses showed that EDTA extraction is the best method for estimating the bioavailability of Pb, As, Ag, Co and Sb to snails. None of the three extractants was efficient for Cd. A multivariate analysis of bioaccumulation data revealed that TM bioavailability and transfer were modulated by exposure sources (soil, humus and vegetation) rather than by soil physico-chemical characteristics. Hence, although the deposition of mining wastes dates back several centuries, these wastes still represent a source of contamination that must be considered to develop relevant site management and environmental risk assessment. (C) 2016 Elsevier Ltd. All rights reserved.
Afficher plus [+] Moins [-]Alterations in juvenile diploid and triploid African catfish skin gelatin yield and amino acid composition: Effects of chlorpyrifos and butachlor exposures Texte intégral
2016
Karamī, ʻAlī | Karbalaei, Samaneh | Zad Bagher, Fariba | Ismail, Amin | Simpson, Stuart L. | Courtenay, Simon C.
Skin is a major by-product of the fisheries and aquaculture industries and is a valuable source of gelatin. This study examined the effect of triploidization on gelatin yield and proximate composition of the skin of African catfish (Clarias gariepinus). We further investigated the effects of two commonly used pesticides, chlorpyrifos (CPF) and butachlor (BUC), on the skin gelatin yield and amino acid composition in juvenile full-sibling diploid and triploid African catfish. In two separate experiments, diploid and triploid C. gariepinus were exposed for 21 days to graded CPF [mean measured: 10, 16, or 31 μg/L] or BUC concentrations [Mean measured: 22, 44, or 60 μg/L]. No differences in skin gelatin yield, amino acid or proximate compositions were observed between diploid and triploid control groups. None of the pesticide treatments affected the measured parameters in diploid fish. In triploids, however, gelatin yield was affected by CPF treatments while amino acid composition remained unchanged. Butachlor treatments did not alter any of the measured variables in triploid fish. To our knowledge, this study is the first to investigate changes in the skin gelatin yield and amino acid composition in any animal as a response to polyploidization and/or contaminant exposure.
Afficher plus [+] Moins [-]Industrial water pollution, water environment treatment, and health risks in China Texte intégral
2016
Wang, Qing | Yang, Zhiming
The negative health effects of water pollution remain a major source of morbidity and mortality in China. The Chinese government is making great efforts to strengthen water environment treatment; however, no studies have evaluated the effects of water treatment on human health by water pollution in China. This study evaluated the association between water pollution and health outcomes, and determined the extent to which environmental regulations on water pollution may lead to health benefits. Data were extracted from the 2011 and 2013 China Health and Retirement Longitudinal Study (CHARLS). Random effects model and random effects Logit model were applied to study the relationship between health and water pollution, while a Mediator model was used to estimate the effects of environmental water treatment on health outcomes by the intensity of water pollution. Unsurprisingly, water pollution was negatively associated with health outcomes, and the common pollutants in industrial wastewater had differential impacts on health outcomes. The effects were stronger for low-income respondents. Water environment treatment led to improved health outcomes among Chinese people. Reduced water pollution mediated the associations between water environment treatment and health outcomes. The results of this study offer compelling evidence to support treatment of water pollution in China.
Afficher plus [+] Moins [-]Dissolved organic carbon content and characteristics in relation to carbon dioxide partial pressure across Poyang Lake wetlands and adjacent aquatic systems in the Changjiang basin Texte intégral
2016
Wang, Huaxin | Jiao, Ruyuan | Wang, Fang | Zhang, Lu | Yan, Weijin
Dissolved organic carbon (DOC) plays diverse roles in carbon biogeochemical cycles. Here, we explored the link between DOC and pCO2 using high-performance size-exclusion chromatography (HPSEC) with UV254 detection and excitation emission matrix (EEM) fluorescence spectroscopy to determine the molecular weight distribution (MW) and the spectral characteristics of DOC, respectively. The relationship between DOC and pCO2 was investigated in the Poyang Lake wetlands and their adjacent aquatic systems. The results indicated significant spatial variation in the DOC concentrations, MW distributions, and pCO2. The DOC concentration was higher in the wetlands than in the rivers and lakes. pCO2 was high in wetlands in which the dominant vegetation was Phragmites australis, whereas it was low in wetlands in which Carex tristachya was the dominant species. DOC was divided into five fractions according to MW, as follows: super-low MW (SLMW, <1 kDa); low MW (LMW, 1–2.5 kDa); intermediate MW (IMW, 2.5–3.5 kDa); high MW (HMW, 3.5–6 kDa); and super-high MW (SMW, > 40 kDa). Rivers contained high proportions of HMW and extremely low amounts of SLMW, whereas wetlands had relatively high proportions of SLMW. The proportion of SMW (SMWp) was particularly high in wetlands. We found that pCO2 significantly positively correlated with the proportion of IMW, and significantly negatively correlated with SMWp. These data improve our understanding of the MW of bioavailable DOC and its conversion to CO2. The present results demonstrate that both the content and characteristics of DOC significantly affect pCO2. pCO2 and DOC must be studied further to help understanding the role of the wetland on the regional CO2 budget.
Afficher plus [+] Moins [-]Winter monsoon variability and its impact on aerosol concentrations in East Asia Texte intégral
2016
Jeong, Jaein I. | Park, Rokjin J.
We investigate the relationship between winter aerosol concentrations over East Asia and variability in the East Asian winter monsoon (EAWM) using GEOS-Chem 3-D global chemical transport model simulations and ground-based aerosol concentration data. We find that both observed and modeled surface aerosol concentrations have strong relationships with the intensity of the EAWM over northern (30–50°N, 100–140°E) and southern (20–30°N, 100–140°E) East Asia. In strong winter monsoon years, compared to weak winter monsoon years, lower and higher surface PM2.5 concentrations by up to 25% are shown over northern and southern East Asia, respectively. Analysis of the simulated results indicates that the southward transport of aerosols is a key process controlling changes in aerosol concentrations over East Asia associated with the EAWM. Variability in the EAWM is found to play a major role in interannual variations in aerosol concentrations; consequently, changes in the EAWM will be important for understanding future changes in wintertime air quality over East Asia.
Afficher plus [+] Moins [-]Towards the suitable monitoring of ingestion of microplastics by marine biota: A review Texte intégral
2016
Wesch, Charlotte | Bredimus, Katja | Paulus, Martin | Klein, Roland
Monitoring plastic ingestion in marine biota is a difficult task, especially regarding ubiquitous microplastics (particles of <5 mm). Due to their microscopic size, evidence for microplastic ingestion is often limited to laboratory studies. The following review provides a comparison and assessment of different microplastic ingestion monitoring procedures. Emphasis is given to the most important steps of current monitoring practice: (1) selecting suitable indicator species, (2) sampling and sample processing, (3) analytical procedures and (4) the prevention of secondary contamination of the sample. Moreover, an overview on ingestion records of microplastics by different marine feeding guilds is presented, including filter, suspension and deposit feeders as well as predators and scavengers. Lastly, monitoring processes are addressed critically in terms of their suitability for achieving the aims of an appropriate monitoring programme. Recommendations for future research priorities are presented with a focus on the necessity of standardised and comparable monitoring procedures in microplastic detection.
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