La législation française demande, depuis 1992, l'établissement de schémas directeurs pour le traitement et l'évacuation des eaux usées. Des zones d'assainissement collectif et des zones d'assainissement non collectif (autonome) doivent être définies. Les autorités locales peuvent, sous certaines conditions, choisir de prendre en charge la responsabilité du contrôle et de la gestion de ces installations privées d'assainissement non collectif. Il devrait progressivement en résulter une augmentation considérable des quantités de matières de vidange issues des fosses septiques qu'il faudra traiter. Les grosses stations d'épuration sont généralement équipées de cuves de dépotage des matières de vidanges extraites et transportées par camions citernes à dépression.. Néanmoins, dans certaines zones rurales la densité de telles installations n'est pas suffisante. Le Cemagref a été sollicité pour étudier, en modèle réduit dans un 1er temps, la faisabilité de stations adaptées et spécialement dédiées au traitement des matières de vidange. La station pilote expérimentale est composée de 2 étages : - s'appuyant sur l'expérience acquise en déshydratation des boues sur lits de séchage plantés de roseaux, le 1er étage a été conçu essentiellement pour retenir, par simple filtration, les concentrations élevées de matières en suspension des matières de vidange. Il apparaît toutefois qu'un important traitement biologique aérobie se produit également dans la couche drainante de gravier, connectée à l'atmosphère et aérée. Des abattements de 70 % sur la DCO dissoute, 79 % sur NK et 66 % concentrations en sels ammoniacaux ont été obtenues. - le 2ème étage est composé de 4 colonnes PVC (0.1 m²), chacune remplie de 15 cm de sable en surface et de quantité croissante de gravier sous-jacent : 0, 20, 40 et 60 cm. Il a notamment été montré que des concentrations plus faibles en DCO (environ 150 mg l-1) peuvent être obtenues et conjointement des concentrations plus faibles en sels ammoniacaux (< 1 mg l-1) avec la colonne remplie de 60 cm de gravier. La contribution de roseaux à améliorer le traitement biologique n'a pu être établie et au plan hydraulique, leur efficacité est discutable au sein d'une période couvrant moins d'un an après leur plantation. / Since 1992, French legislation requires the creation of master plans for evacuation and treatment of wastewater. Zones of collective and individual (on-site) treatment have to be defined. Local authorities may take responsibility for controlling and operating private on-site treatment systems. This will result in a considerable increase in the amount of sludge from septic tanks (faecal sludge : FS) that needs to be treated. Large wastewater treatment plants are able to treat such FS transported and removed with vacuum trucks. Nevertheless, in some rural areas, there are fewer of these plants. Cemagref has been asked to study the feasibility of treatment plants specially designed for treating FS. The pilot plant is made up of 2 stages : - the 1st stage is designed mainly to achieve filtration of the high concentrations of suspended solids in the FS. It also appears that an important aerobic biological treatment process occurs in the drainage gravel layer connected to the atmosphere. Removal rates of 70 % for soluble COD, 79 % for KN and 66 % for ammonia concentrations have been obtained. - the 2nd stage consists of 4 PVC columns (0.1m2), each filled with 15 cm of sand on top of 0, 20, 40 and 60 cm of gravel. COD concentrations around 150 mg 1-1 and low ammonia concentrations (< 1 mg 1-1) can be achieved with columns filled with 60 cm of gravel. The extent to which the reeds improve the biological treatment has not been established and from a hydraulic point of view, their effectiveness is debatable over a period of less than one year after being planted.

L'intérêt croissant porté aux pollutions diffuses - notamment d'origine agricole - par les gestionnaires de la ressource en eau a rendu nécessaire la mise en oeuvre de méthodologies adaptées, pour prendre en compte les multiples facteurs qui interviennent "dans les transferts des polluants (agronomique, climatiques, hydrologiques etc ) et dégager les politiques à mettre en oeuvre pour en corriger les effets.

International audience | Climate change and human activities induce an increased frequency and intensity of cyanobacterial blooms which could release toxins to aquatic ecosystems. Zooplankton communities belong to the first affected organisms, but in tropical freshwater ecosystems, this issue has yet been poorly investigated. We tested two questions (i) if the tropical Daphnia lumholtzi is capable to develop tolerance to an ecologically relevant concentration of purified microcystin-LR and microcystins from cyanobacterial extract transferable to F1 and F2 generations? And (ii) would F1 and F2 generations recover if reared in toxin-free medium? To answer these questions, we conducted two full factorial mutigenerational experiments, in which D. lumholtzi was exposed to MC-LR and cyanobacterial extract at the concentration of 1 μg L microcystin continuously for three generations. After each generation, each treatment was spit into two one reared in the control (toxin free) while the other continued in the respective exposure. Fitness-related traits including survival, maturity age, body length, and fecundity of each D. lumholtzi generation were quantified. Though there were only some weak negative effects of the toxins on the first generation (F0), we found strong direct, accumulated and carried-over impacts of the toxins on life history traits of D. lumholtzi on the F1 and F2, including reductions of survival, and reproduction. The maturity age and body length showed some inconsistent patterns between generations and need further investigations. The survival, maturity age (for extract), and body length (for MC-LR) were only recovered when offspring from toxin exposed mothers were raised in clean medium for two generations. Chronic exposure to long lasting blooms, even at low density, evidently reduces survival of D. lumholtzi in tropical lakes and reservoirs with ecological consequences.

International audience

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

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.

New approach to identify and categorize pesticide metabolites in soil combining suspect screening metabolomics with in silico molecular typology. 5th International Conference on Environmental Pollution and Remediation (ICEPR). 5th International Conference on Environmental Pollution and Remediation (ICEPR)

[Departement_IRSTEA]Eaux [TR1_IRSTEA]GEUSI | Many articles have dealt with the advantages of spatially discriminating the abatement effort when the pollution is non-uniformly mixed. However, few authors have attempted to identify the impact of certain model parameters on the advantage of this discrimination. These parameters are the transfer coefficients, the parameters of the abatement cost function or the level of the quality standard. In this article, we studied the role of the slope of the environmental benefit function on the advantages of spatially discriminating pollution abatement efforts. It appears that the relative increase in the net social benefit between a uniform and a perfectly discriminated control is not affected by this slope. However, in the case of partial discrimination, a steeper benefit slope increases the optimal number of zones.

International audience | Organochlorinated compounds including PolyChloroBiphenyles, Dichloro-DiphenylTrichloroethan and metabolites are determinated in Stenella coeruleoalba (n = 37) stranded on the french Mediterranean coasts from 2007 till 2009. Studies are carried out on lung, muscle, kidney, liver, and blubber. The sought-after compounds are all detected to variable levels in each tissue and organ. In general, total PCBs are the most abondant, followed by total DDTs. The concentration (in ng g(-1) of lipid weight) in blubber of S. coeruleoalba, varied from 2,052 to 158,992 for PCBs and from 1,120 to 45,779 for DDTs. The ratios DDE/tDDTs are higher than 80% in almost all samples. The overall results of this work, compared to previous studies concerning the Mediterranean Sea, seems to confirm the tendency to a decrease of the contamination by organics compounds for the cetaceans in the Western Mediterranean Sea. (C) 2012 Elsevier Ltd. All rights reserved.