POLYCHLORINATED-BIPHENYLS PARTITIONING IN WATERS FROM RIVER, FILTRATION PLANT AND WASTE-WATER PLANT - THE CASE FOR PARIS (FRANCE)

The partitioning of PCBs between the aqueous and particulate phases was studied from January to December 1987 in the Seine river at Paris, as well as the quality of the drinking water produced in the Orly plant. At the same time the concentrations in the influent and the effluent of the wastewater plant of Achéres were measured. Mean concentration in the Seine river at Paris was 115 ng 1-1 in 1986, and 130 ng l-1 at Orly (upstream Paris) in 1987, which corresponds to the "heavily polluted" class of the WHO. Evolution of PCB concentration and speciation in waters were studied following the hydrological cycle, the suspended matter content, its mineralogy and particulate organic carbon content. At variance with the commonly accepted opinion, about three quarters of PCBs (73%) in the Seine were carried by the aqueous phase, with no notable influence of the hydrological cycle: suspended matters were insufficient (25 mg l-1 mean value) to adsorb the majority of PCBs and their adsorption capacity varied in opposition with their concentration. Therefore 67% of PCBs of the source water were not retained by the treatment plant, and the mean concentration of the drinking water was 79 ng l-1. However in most samples the concentration of PCBs was below the 100 ng 1-1 norm of the EEC. In wastewaters the proportion of "particulate" PCBs was only 55%, probably due to their dissolution in greases and oils. The removal rate varied from 18 to 83% (mean 54%). Mean concentrations were 650 in wastewaters and 280 ng 1-1 at the outlet of the secondary settling basin. The annual estimated flux was 95 mg per capita. © 1990.