Infodoc : Sciences, Techniques et Culture

As part of the artWET LIFE environment project (06 ENV/F/000133), two buffer zones, an artificial wetland and a forest buffer, located at Bray (France) were assessed for their potential at reducing pesticide pollution coming from a 46-ha tile-drained watershed. Because of limited land availability, treating the entire volume was not possible but focusing on the most concentrated effluents appeared to be a good strategy to achieve pesticide abatement. The three-year results showed that both systems lowered down pesticide concentrations and loads by more than 40 %. However, a wide range of efficiencies was recorded. The most contrasted results were obtained for the fairly mobile herbicide isoproturon. On-site multi-tracer experiments concluded in a 66.5-h water residence time in the art[...]

As part of the artWET LIFE environment project (06 ENV/F/000133), two buffer zones, an artificial wetland and a forest buffer, located at Bray (France) were assessed for their potential at reducing pesticide pollution coming from a 46-ha tile-drained watershed. Because of limited land availability, treating the entire volume was not possible but focusing on the most concentrated effluents appeared to be a good strategy to achieve pesticide abatement. The three-year results showed that both systems lowered down pesticide concentrations and loads by more than 40 %. However, a wide range of efficiencies was recorded. The most contrasted results were obtained for the fairly mobile herbicide isoproturon. On-site multi-tracer experiments concluded in a 66.5-h water residence time in the artificial wetland. Delay was observed in pesticide transfer probably due to adsorption, but desorption was also suspected. Wetland sediments, wetland plants, forest soil and litter were sampled on-site. [...]
Dans le cadre du projet européen LIFE ArtWET (06 ENV/F/000133), deux zones tampons (ZTs), une zone humide artificielle (ZHA) et une zone tampon forestière (ZTF), situées à Bray (France), ont été évaluées pour leur efficacité à réduire la pollution par les pesticides venant d'un bassin versant agricole drainé de 46 ha. Traiter l'ensemble des volumes n'étant pas possible, une bonne stratégie de traitement semble être de cibler les volumes les plus concentrés en pesticides. Les trois ans de données indiquent en moyenne une réduction d'au moins 40 % des concentrations et des charges en pesticides dans les deux ZTs, bien q'une forte variabilité ait été notée. L'isoproturon, un herbicide mobile, a donné les résultats les plus contrastés. Des expérimentations de traçage ont permis d'estimer le temps de rétention hydraulique à 66.5 h dans la ZHA. Les retards observés sur le transfert des pesticides à travers des ZTs semblent dus à l'adsorption, bien que des phénomènes de désorption soient aussi suspectés. Des sédiments et des plantes de la ZHA ainsi que du sol et de la litière de la ZTF ont été prélevés. [...]