Origin and distribution of polyaromatic hydrocarbons and polychlorobiphenyls in urban effluents to wastewater treatment plants of the Paris area (France).

Polyaromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs), were investigated in urban effluents to wastewater treatment plants in the Paris area (France), under different meteorological conditions. The Achères plant was considered with special attention because of its particular features. Wastewater PAH concentration level was 6 fold higher than that of PCBs. In March, PCB concentrations did not vary whatever the meteorological conditions whereas, for PAHs, they were markedly higher during rainy episodes. In September, concentrations of both pollutants increased due to rainy weather. The rise was 30 fold stronger for PAHs. Daily fluxes displayed the same trends. This suggests that the contribution of atmospheric wet deposition to wastewater contamination prevails for PCBs. In contrast, PAHs appeared to originate mainly from urban runoff processes.