Water-Quality Diagnosis and Metal Distribution in a Strongly Polluted Zone of Deule River (Northern France)

摘要

Using ICP-AES and ICP-MS, several metals were analyzed in water and suspended particulate matter (SPM) samples collected under normal turbidity conditions at various stations from Deule river (in northern France) to assess the impact of a former smelting plant on the fate of paniculate elements and on the water quality in this aquatic environment. Compared to their regional background, particulatc Pb, Zn and Cd were found tornbe most enriched, suggesting anthropogenic inputs from bed sediments into the water column mainly due to physical disturbances induced by barges traffics. Conversely, no significant enrichments of particulate metals such as Cu, Cr and Ni were observed in Deule SPM. Characterization of SPM with analyses of mineralogical and chemical compositions-using environmental scanning electron microscopy equipped with an energy dispersive X-ray spectrometer (ESEM/ EDS)-indicated the presence of micro-specimens attributed to anthropogenic minerals, mostly PbS and ZnS. The calculated enrichment index (or the geo-accumulation index, I_(geo)), enrichment factor (EF) and the partition coefficient (K_d) confirmed that SPM was strongly polluted in cadmium, lead and zinc, moderately polluted in copper and unpolluted in chromium and nickel. Based on the analytical data obtained for SPM from the BCR (European Community Bureau of Reference) sequential extraction scheme, it was concluded that: (i) the reducible phases were largely more important for the binding of Pb and Cd than that of Zn and Ni and in a lesser extent Cu and Cr; (ii) copper was found to be mostly associated with the sulphides/ organics fraction; (iii) chromium with a lithogenic origin was extracted in the largest percentage in the residual phase; and (iv) zinc was bound to the exchangeable-carbonate phase in the largest percentage in the particles analysed, followed by nickel and cadmium, suggesting that these metals might be easily remobilized if changes in environmental conditions would occur.