International audienceParticulate heavy metals and hydrocarbons have been measured in Paris urban area during dry and wet weather periods. A 18 months campaign realised upstream Paris» in the river Seine, has evidenced higher heavy metals concentrations during summer than winter. Summer campaigns demonstrate a strong impact of Paris urban area and its discharges. The direct impact of highly polluted urban overflows into River Seine has been evidenced as a weak immediate but significant retarded discharge of particulate toxic metals. Ratios of significant PAH's allows a better understanding of sources and transport of hydrocarbon in urban areas. Furthermore, relation of these impacts to those observed for heavy metals brings useful informati...