International audience | The bioavailability of trace elements (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Zn) in lowly to moderately contaminated coastal sediments from the Berre lagoon, France, was assessed by comparing their potentially bioavailable concentrations and bioaccumulated concentrations in the polychaete Alitta succinea. No linear correlations were observed contrarily to what is generally observed in similar works in areas with highly contaminated sediment. Correlations between trace and major elements (Fe, Ca, S, Mg, P, Al) in Alitta succinea tissues and their distribution in organism tissues show that, in such lowly to moderately contaminated sediments, biological variabilities should be considered. Normalization procedures allow to take into account these variabilities and to identify that sediment contamination is partly involved in the benthic ecosystem degradation of the Berre lagoon. Alitta succinea cannot be used as relevant bioindicator for Zn and Co bioavailability in sediment, since these elements are regulated by this organism.

Sediment samples were randomly taken in March and August 2017 at the strandlines of nine locations along the coast of Slovenia (Adriatic Sea, Mediterranean). Microparticles were isolated by density separation in saturated aqueous NaCl-solutions and analysed by infrared spectroscopy (ATR-FTIR). 11.3% of these particles were unambiguously confirmed as microplastics. Another 8.2% showed plastic characteristics but failed ATR-FTIR validation. 4.3% were naturally organic. The rest was unidentified material (76.2%). The average microplastic densities were 0.5 ± 0.5 MP kg−1 in March and 1.0 ± 0.8 MP kg−1 in August. The microplastics comprised fragments, fibres, films, and foams. The characteristics of the microplastics suggest origin from single-used plastic products and from aquaculture. Compared to other studies and sites, the microplastic pollution of the Slovenian coast appeared low. The validity of the results is discussed with respect to microplastic distribution and patchiness, sampling strategies, methodology, and scientific claims.

National audience

Benzene, toluene, ethylbenzene, xylenes, naphthalene and n-hexane evaporating from a thin oil film was measured for 30 min in a small-scale test system at 2 and 13 °C and the impact of physicochemical properties on airborne benzene with time after bulk oil release was studied. Linear mixed-effects models for airborne benzene in three time periods; first 5, first 15 and last 15 min of sampling, indicated that benzene content in fresh oil, oil group (condensate/light crude oil) and pour point were significant determinants explaining 63–73% of the total variance in the outcome variables. Oils with a high pour point evaporated considerably slower than oils with a low pour point. The mean air concentration of total volatile organic compounds was significatly higher at 13 °C (735 ppm) compared to 2 °C (386 ppm) immediately after release of oil, but at both temperatures the concentration rapidly declined. | acceptedVersion

The evaluation of the content of metals and metalloids in particulate matter (PM) and in atmospheric deposition in areas impacted by local industries is essential from an environmental and health risk perspective. In this study, the PM10 levels and atmospheric deposition fluxes of potentially toxic metals and metalloids were quantified at three urban sites of the Cantabrian region (northern Spain), located at different distances downwind of a Mn alloy plant. The content of Mn, V, Fe, Ni, Cu, Zn, As, Mo, Cd, Sb and Pb in PM10 and in the water-soluble and insoluble fractions of the deposition was determined by ICP-MS. Among the studied elements, the highest concentrations in PM10 and deposition rates were found for Mn, Fe, Zn and Pb, associated with the Mn alloy industry, and for Cu, related to non-exhaust traffic emissions. The levels of Mn, Fe, Zn and Pb in PM10 were higher in autumn, when the most frequent winds blow from the S-SW, whereas their highest deposition rates were found in winter and autumn, which are characterized by high monthly average precipitations. The water-soluble fraction of the atmospheric deposition of most metals increased with distance from the Mn alloy plant. The highest water-soluble fractions were found for Ni (72%), Zn (62%), Cu (60%) and Mn (49%). These results will be useful for the health risk assessment of the metal exposure associated with Mn alloy plants, as well as for the evaluation of the metal burden to soil, water and ecosystems related to this industrial activity. | This work was financially supported by the Spanish Ministry of Economy and Competitiveness (MINECO) through the CTM2013-43904R Project. Ana Hernández-Pellón would like to thank the Ministry of Economy and Competitiveness (MINECO) for the FPI grant awarded, reference number BES-2014-068790.

International audience | Mercury pollution is currently a major public health concern, given the adverse effects of mercury on wildlife and humans. Soil plays an essential role in speciation of mercury and its global cycling, while being a habitat for a wide range of terrestrial fauna. Soil fauna, primarily soil-feeding taxa that are in intimate contact with soil pollutants are key contributors in the cycling of soil mercury and might provide relevant indications about soil pollution. We studied the enrichment of various mercury species in the nests and bodies of soil-feeding termites Silvestritermes spp. in French Guiana. Soil-feeding termites are the only social insects using soil as both shelter and food and are major decomposers of organic matter in neotropical forests. Nests of S. minutus were depleted in total and mobile mercury compared to nearby soil. In contrast, they were enriched 17 times in methylmercury. The highest concentrations of methylmercury were found in body of both studied termite species, with mean bioconcentration factors of 58 for S. minutus and 179 for S. holmgreni relative to the soil. The assessment of the body distribution of methylmercury in S. minutus showed concentrations of 221 ng g−1 for the guts and even higher for the gut-free carcasses (683 ng g−1), suggesting that methylmercury is not confined to the gut where it was likely produced, but rather stored in various tissues. This enrichment in the most toxic form of Hg in termites may be of concern on termite predators and the higher levels in the food chain that may be endangered through prey-to-predator transfers and bioaccumulation. Soil-feeding termites appear to be promising candidates as bio-indicators of mercury pollution in soils of neotropical rainforest ecosystems.

This is the post-print version of the following article: "Massive plastic pollution in a mega-river of a developing country: Sediment deposition and ingestion by fish (Prochilodus lineatus)", which has been published in final form at https://www.sciencedirect.com/science/article/pii/S0269749119328520 | International audience | The aim of this study was to determine the amount, composition and origin of plastic debris in one of the world largest river, the Paraná River in Argentina (South America), focusing on the impact of urban rivers, relationships among macro, meso and microplastic, socio-political issues and microplastic ingestion by fish.

International audience | Mercury pollution is currently a major public health concern, given the adverse effects of mercury on wildlife and humans. Soil plays an essential role in speciation of mercury and its global cycling, while being a habitat for a wide range of terrestrial fauna. Soil fauna, primarily soil-feeding taxa that are in intimate contact with soil pollutants are key contributors in the cycling of soil mercury and might provide relevant indications about soil pollution. We studied the enrichment of various mercury species in the nests and bodies of soil-feeding termites Silvestritermes spp. in French Guiana. Soil-feeding termites are the only social insects using soil as both shelter and food and are major decomposers of organic matter in neotropical forests. Nests of S. minutus were depleted in total and mobile mercury compared to nearby soil. In contrast, they were enriched 17 times in methylmercury. The highest concentrations of methylmercury were found in body of both studied termite species, with mean bioconcentration factors of 58 for S. minutus and 179 for S. holmgreni relative to the soil. The assessment of the body distribution of methylmercury in S. minutus showed concentrations of 221 ng g−1 for the guts and even higher for the gut-free carcasses (683 ng g−1), suggesting that methylmercury is not confined to the gut where it was likely produced, but rather stored in various tissues. This enrichment in the most toxic form of Hg in termites may be of concern on termite predators and the higher levels in the food chain that may be endangered through prey-to-predator transfers and bioaccumulation. Soil-feeding termites appear to be promising candidates as bio-indicators of mercury pollution in soils of neotropical rainforest ecosystems.

International audience | Assessing the ecological risk of combined pollution, especially from a holistic perspective with the consideration of the overarching functions of soil ecosystem, is crucial and beneficial to the improvement of ecological risk assessment (ERA) framework. In this study, four soils with similar physicochemical properties but contrasting heavy metals contamination levels were selected to explore changes in the integrated functional sensitivity (MSI), resistance (MRS) and resilience (MRL) of soil microbial communities subjected to herbicide siduron, based on which the ecological risk of the accumulation of siduron in the four studied soils were evaluated. The results suggested that the microbial biomass carbon, activity of denitrification enzyme and nitrogenase were indicative of MSI and MRS, and the same three parameters plus soil basal respiration were indicative of MRL. Significant dose-effect relationships between siduron residues in soils and MSI, MRS and MRL under combined pollution were observed. Heavy metal polluted soils showed higher sensitivity and lower resistance to the additional disturbance of herbicide siduron due to the lower microbial biomass, while the resilience of heavy metal polluted soils was much higher due to the pre-adaption to the chemical stresses. The quantifiable indicator microbial functional stability was incorporated in the framework of ERA and the results showed that the accumulation of siduron in the studied soils could exhibit potential harm to the integrated functional stability of soil microbial community. Thus, this work provides insights into the application of integrated function of soil microbial community into the framework of ERA.