The aim of this study was to identify primary flow paths involved in the chlordecone (CLD) river contamination and quantify the CLD fluxes to assess CLD pollution levels and duration according to a typical catchment of the banana cropping area in the French Indies (Guadeloupe): the Perou Catchment (12 km(2)) characterized by heavy rainfall (5686 mm year(-1)). Three sub-catchments (SC1, SC2 and SC3) were studied during the hydrological year 2009-2010: a pedological survey combined with a spatialized hydrochemical approach was conducted. The average soil concentration is higher in the Perou Catchment (3400 mu g kg(-1)) than in the entire banana cropping area in Guadeloupe (2100 mu g kg(-1)). The results showed that CLD stocks in soils vary largely among soil types and farming systems: the weakest stocks are located upstream in SC1 (5 kg ha(-1)), where a majority of the area is non-cultivated; medium stocks are located in Nitisols downstream in SC3 (9 kg ha(-1)); and the greatest stocks are observed in SC2 on Andosols (12 kg ha(-1)) characterized by large farms. The annual water balance and the hydro-chemical analysis revealed that the three sub-catchments exhibited different behaviors. Perou River contamination was high during low flows, which highlighted that contamination primarily originated from groundwater contributions. The results showed that only a small part of the catchment (SC2), contributing little to the water flow, comprises a major CLD contribution, which is in agreement with the highly contaminated andosol soils observed there. Another significant result considers that at least 50 years would be required to export the totality of the actual CLD soil stocks retained in the topsoil layer. The actual time for soil remediation will however be much longer considering (i) the necessary time for the chlordecone to percolate and be stored in the shallow aquifers and (ii) its travel time to reach the river.rights reserved.

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. | 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.

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L’azote, si cher à nos campagnes

International audience | Shipping noise is a threat to marine wildlife. Grey seals are benthic foragers, and thus experience acoustic noise throughout the water column, which makes them a good model species for a case study of the potential impacts of shipping noise. We used ship track data from the Celtic Sea, seal track data and a coupled ocean-acoustic modelling system to assess the noise exposure of grey seals along their tracks. It was found that the animals experience step changes in sound levels up to ~20dB at a frequency of 125Hz, and ~10dB on average over 10 1000Hz when they dive through the thermocline, particularly during summer. Our results showed large seasonal differences in the noise level experienced by the seals. These results reveal the actual noise exposure by the animals and could help in marine spatial planning. 2

La mesure des polluants…vers la démesure ?. Pollution chimique : la santé en jeu

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. | 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.

peer reviewed | Previous studies described high concentrations of mercury (Hg) and selenium (Se) in the blood of harbour seals, Phoca vitulina from the North Sea. In the present study, we evaluated the in vitro potential protective effects of sodium selenite (Na2SeO3) and selenomethionine (SeMet) on cell proliferation of harbour seal lymphocytes exposed to MeHgCl 0.75 µM. In vitro exposure of ConA-stimulated T lymphocytes resulted in severe inhibition of DNA synthesis, likely linked to severe loss of mitochondrial membrane potential at 0.75 µM. Neither selenite nor SeMet showed a protective effect against MeHg toxicity expressed at the T lymphocyte proliferation level for harbour seals. Selenite and SeMet did not show negative effects regarding lymphocyte proliferation and mitochondrial membrane potential. To conclude, our results clearly demonstrated that MeHg affected in vitro immune cells exposure with no protective effects of selenium at a molar ratio Hg:Se of 1:10 in harbour seals from the North Sea.