Présentations Colloques

Poster
7.03
Session 7.03: Agricultural and sanitation contaminants and implications for water services and health
Chevrol (orateur)
Needs of changes in agricultural practices to sustainably protect aquifers of Eocene age, exploited for drinking water supply, in the “Vexin Français” natural area.
In the Val d’Oise department, in the heart of the regional natural park of Vexin Français, twelve catchments supply now 42 000 inhabitants in drinking water. Wells abstract water from shallow aquifers in rough limestone of Lutetian age or sand of Ypresian. They provide flow rates superior to the needs. However, abstracted water contains nitrate concentrations exceeding the admitted maximum of 50 mg l and about 0.2 Ig l of Atrazine or its metabolites. Over the past few years, treatments with ion exchange resins (nitrates) and active coals filters (pesticides) have been implemented by local authorities. Nevertheless, these curative treatments do not constitute a lasting solution as shown by the constant increase in nitrate observed in raw waters and confirmed by the emergence of new molecules used as crop protection agents that are authorised in conventional agriculture.**In this context, these twelve catchments were included in the list of priority catchments under the Order of the 30 May 2008 (Grenelle I), then under the environmental Convention of the 22 September 2015 (Grenelle II). Aware of the resource protection issue, in February 2016, the ten local authorities concerned organized a public order grouping. Local elected officials, supported by technical assistance of the Val d’Oise department and the Seine Normandie water agency, gave themselves 2 years for delineating catchment feeding areas, assessing intrinsic vulnerability of the aquifers, making a diagnosis of hazardous practices and elaborating action programmes. This grouping is the first stage of a strategy which aims at driving a dynamic to promote the resource protection by the construction of a common territory. These authorities, by pooling financial resources, will be able to coordinate projects to help the emergence of new technical channels based on low level of farm inputs, to promote products from organic farming and adopt new land policies.**
France