Contamination des eaux pluviales d'un bassin versant résidentiel dense amont

Stormwater from a 0.8 ha watershed and atmospheric deposits were collected in a dense residential area to determine the levels of some micropollutants (PAHs, PCBs, nonylphenols, copper, lead, zinc). Atmospheric inputs account for 10 to 38% of contamination (except for PCBs which are at 100% atmospheric) showing a substantial production within the watershed. The runoff contamination at the scale of this small catchment area is however lower than observed on large urban watersheds (∼100 ha) with similar land use, indicating that stormwater source control is an interesting solution for stormwater management. It has also been shown that the contamination in some micropollutants evolves according to a given scale and is mainly dissolved, which is in contrast to what is classically considered. Consequently, the choice of the treatment devices must be adapted to the management scale and the type of contaminant of concern.