Atmospheric deposition of toxics onto the Seine Estuary, France: example of polycyclic aromatic hydrocarbons

Abstract. Concentrations of Polycyclic Aromatic Hydrocarbons (PAH) were measured in precipitation samples on a weekly basis between March and October 2001, at four sites in the Seine Estuary (France). Mean concentrations of total PAHs (S 14 PAHs) ranged from 38 to 141 ng L^-1. Fluoranthene, phenanthrene and pyrene were the dominant PAH compounds and were detected in each sample. The six potential carcinogenic PAHs accounted for 20 to 25% of the total PAH concentration in bulk deposition. The PAH signatures in bulk (wet and dry) deposition and surface water were also compared to investigate source/sink relationships. Seasonal patterns were observed with maximum loading occurring during the colder months of the studied period (March and April). Mean values of daily flux reported for S 14 PAHs ranged from 108 to 267 ng m^-2 d^-1. Spatial influences were also observed, indicating both localized and long-range atmospheric source inputs (controlled by hydroclimatic parameters).