International audience | This study aimed at determining the fate of trace elements (TE) following soil organic waste (OW) application. We used a unique combination of X-ray absorption spectroscopy analyses, to determine TE speciation, with incubation experiments for in situ monitoring of TE availability patterns over a time course with the technique of the diffusive gradients in thin films (DGT). We showed that copper (Cu) and zinc (Zn) availability were both increased in OW-amended soil, but their release was controlled by distinct mechanisms. Zn speciation in OW was found to be dominated by an inorganic species, i.e. Zn sorbed on Fe oxides. Zn desorption from Fe oxides could explain the increase in Zn availability in OW amended soil. Cu speciation in OW was dominated by organic species. Cu release through the mineralization of organic carbon from OW was responsible for the increase in Cu availability. (C) 2016 Elsevier Ltd. All rights reserved.

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.

Microcystins (MCs) are cyanobacterial heptapeptides, produced by several genera and species of cyanobacteria, which have been involved in poisoning of animals throughout the world and have also been implicated in human health problems. They are regarded as the most frequently occurring and widespread of the cyanotoxins, with more than 100 MC variants reported to date including the present study. The lake des Oiseaux is a shallow permanent freshwater lake located in north-eastern Algeria. It is an important natural reserve playing a major role for the migratory birds after the crossing of the Mediterranean Sea and from the Sahara desert. In recent years, possibly related to increased eutrophication of the lake, massive blooms of cyanobacteria identified as Microcystis spp. have been observed. A bloom sample collected in September 2013 was analyzed by the serine/threonine phosphatase PP2A inhibition assay and liquid chromatography-mass spectrometry to determine respectively, the total concentration of MCs and the different variants of these toxins present. The results revealed that the Microcystis spp. bloom sample contained microcystins of which 21 putatively congeners were detected. Among these, 12 known microcystins (MC-RR, MC-LR, MC-FR, MC-WR, MC-YR, MC-LA, MC-(H4)YR, MC-HilR, [Asp3]MC-RAba, and [Glu(OCH3)6]MC-LR) and two new congeners ([Asp3]MC-HarAba and [Glu(OCH3)6]MC-FR) were characterized, considering their molecular mass and the fragment ions produced by collision-induced dissociation of the [M+H]+ ions. MC-RR was the major (43.4%) in the bloom sample.

International audience | In the present study, trace elements and persistent organic pollutants (POPs) were quantified from Magnificent frigatebirds (Fregata magnificens) breeding at a southern Atlantic island. Stable isotope ratio of carbon (δ13C) and nitrogen (δ15N) were also measured to infer the role of foraging habitat on the contamination. For another group from the same colony, GPS tracks were recorded to identify potential foraging areas where the birds may get contaminated. Fourteen trace elements were targeted as well as a total of 40 individual POPs, including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). The concentration of Hg in the blood was up to 6 times higher in adults (5.81 ± 1.27 mg g-1 dw.) than in nestlings (0.99 ± 0.23 mg g-1 dw.). A similar pattern was found for POPs. PPCBs was the prevalent group both in adults (median 673, range 336 -2801 pg g-1 ww.) and nestlings (median 41, range 19-232 pg g-1 ww.), followed by the sum of dichlorodiphenyltrichloroethanes and metabolites (∑DDTs), showing a median value of 220 (range 75-2342 pg g-1 ww.) in adults and 25 (range 13-206 pg g-1 ww.) in nestlings. The isotope data suggested that the accumulation of trace elements and POPs between adults and nestlings could be due to parental foraging in two different areas during incubation and chick rearing, respectively, or due to a shift in the feeding strategies along the breeding season. In conclusion, our work showed high Hg concentration in frigatebirds compared to non-contaminated seabird populations, while other trace elements showed lower values within the expected range in other seabird species. Finally, POP exposure was found generally lower than that previously measured in other seabird species.

International audience | A dynamic coupled biogeochemical-ecological model was used to simulate the effects of nitrogen deposition and climate change on plant communities at three forest sites in France. The three sites had different forest covers (sessile oak, Norway spruce and silver fir), three nitrogen loads ranging from relatively low to high, different climatic regions and different soil types. Both the availability of vegetation time series and the environmental niches of the understory species allowed to evaluate the model for predicting the composition of the three plant communities. The calibration of the environmental niches was successful, with a model performance consistently reasonably high throughout the three sites. The model simulations of two climatic and two deposition scenarios showed that climate change may entirely compromise the eventual recovery from eutrophication of the simulated plant communities in response to the reductions in nitrogen deposition. The interplay between climate and deposition was strongly governed by site characteristics and histories in the long term, while forest management remained the main driver of change in the short term.

International audience | Periurban areas, zone of transition between urban and rural areas, are submitted to several sources of pollution, both gaseous and particulate. These pollutions originate from local sources such as residential sector, traffic road and agricultural activities, but also from regional ones from adjacent urban and (pseudo-)natural areas. This paper presents a synthesis of the different sources affecting air quality in periurban areas. It is clear that pollutions from anthropogenic activities cannot be fully dissociated to those from (pseudo-)natural ecosystem functioning in these areas. Finally, the atmospheric pollution issues are discussed in emphasis with periurban agriculture, already present and under development in these areas due to the development of short food supply chains and local food consumptions. | Les territoires périurbains, zones de transition entre les zones urbaines et rurales, sont soumis à de nombreuses pollutions à la fois gazeuses et particulaires. Ces pollutions proviennent de sources locales comme les activités résidentielles, le trafic routier et les activités agricoles, mais également de sources régionales issues des activités urbaines et des émissions des zones (pseudo-)naturelles adjacentes. Cet article présente une synthèse des différentes sources de pollution affectant la qualité de l’air en milieu périurbain. Il est évident que les pollutions purement anthropiques ne peuvent être dissociées de celles issues du fonctionnement des écosystèmes (pseudo-)naturels dans ces espaces. Enfin, les enjeux vis-à-vis de l’agriculture périurbaine, fortement présente et en développement du fait d’une volonté de consommer des productions locales, sont discutés.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA | International audience | Passive sampling devices (PS) are widely used for pollutant monitoring in water, but estimation of measurement uncertainties by PS has seldom been undertaken. The aim of this work was to identify key parameters governing PS measurements of metals and their dispersion. We report the results of an in situ intercomparison exercise on diffusive gradient in thin films (DGT) in surface waters. Interlaboratory uncertainties of time-weighted average (TWA) concentrations were satisfactory (from 28% to 112%) given the number of participating laboratories (10) and ultra-trace metal concentrations involved. Data dispersion of TWA concentrations was mainly explained by uncertainties generated during DGT handling and analytical procedure steps. We highlight that DGT handling is critical for metals such as Cd, Cr and Zn, implying that DGT assembly/dismantling should be performed in very clean conditions. Using a unique dataset, we demonstrated that DGT markedly lowered the LOQ in comparison to spot sampling and stressed the need for accurate data calculation.

International audience | Cephalopod beaks found in the diet of predators have been amajor source of scientific information. In this study,we evaluated the usefulness of DNA and contaminants analysis (total mercury — T-Hg) in cephalopod beaks inorder to assess their applicability as tools in marine ecology studies. We concluded that, when applying DNAtechniques to cephalopod beaks from Antarctic squid species, when using flesh attached to those beaks, it waspossible to obtain DNA and to successfully identify cephalopod species; DNA was not found on the beaks themselves.This study also showed that it is possible to obtain information on T-Hg concentrations in beaks: the T-Hgconcentrations found in the beaks were 6 to 46 times lower than in the flesh of the same cephalopod species.More research on the relationships of mercury concentrations in cephalopod beaks (and other tissues), intraandinter-specifically, are needed in the future.

Interactions between climate change and air pollution in the context of agriculture. Agroecosystems are sources and sinks of atmospheric pollutants and greenhouse gases. They are therefore involved in climate change and air pollution and their cross-relations. This contribution can be positive or negative. It results from complex processes, both direct and indirect, which is related to a range of topics: increase or decrease of emission and deposition, increase in fire frequency, change in plant protection etc. As for most of biological processes, there are large uncertainties and knowledge is lacking over a range of fields. However it is necessary to have a global overview of the involved processes and drivers when trying to limit the contribution of agroecosystem both to climate change and air pollution, with attention to the economic sustainability of agriculture under global change. Moreover agriculture activities refer to public policies related not only to climate change and air pollution but also water pollution or protection of the environment. These policies may interact positively or be antagonist. | Les agroécosystèmes sont des sources et des puits de polluants atmosphériques et de gaz à effet de serre et, par là-même, ils interviennent dans les relations entre climat et pollution de l’air. Cette contribution, positive ou négative, résulte de processus complexes, à la fois directs et indirects, et prend des formes très diverses : augmentation ou diminution des émissions et dépôts, augmentation attendue de la fréquence des feux, modification de la protection phytosanitaire etc. Comme pour la plupart des processus biologiques, les incertitudes sont importantes et les verrous de connaissances restent nombreux, alors qu’une connaissance des différents facteurs d’influence, naturels et anthropiques est nécessaire pour limiter la contribution des agroécosystèmes à la fois au changement climatique et à la pollution de l’air, tout en préservant les performances économiques de l’activité agricole. Enfin, l’agriculture est concernée par tout un ensemble de politiques publiques relatives au changement climatique et à la pollution de l’air, mais également à la pollution des eaux et à la protection de l’environnement, politiques publiques qui peuvent interagir en synergie ou être antagonistes.

International audience | The replenishment and persistence of marine species is contingent on dispersing larvae locating suitable habitatand surviving to a reproductive stage. Pelagic larvae rely on environmental cues to make behavioural decisionswith chemical information being important for habitat selection at settlement. We explored the sensory worldof crustaceans and fishes focusing on the impact anthropogenic alterations (ocean acidification, red soil, pesti-cide) have on conspecific chemical signals used by larvae for habitat selection. Crustacean (Stenopus hispidus)and fish (Chromis viridis) larvae recognized their conspecifics via chemical signals under control conditions. Inthe presence of acidified water, red soil or pesticide, the ability of larvae to chemically recognize conspecificcues was altered. Our study highlights that recruitment potential on coral reefs may decrease due to anthropo-genic stressors. If so, populations of fishes and crustaceans will continue their rapid decline; larval recruitmentwill not replace and sustain the adult populations on degraded reefs