SPECIATION STUDY OF CHROMIUM, COPPER AND NICKEL IN COASTAL ESTUARINE SEDIMENTS POLLUTED BY DOMESTIC AND INDUSTRIAL EFFLUENTS

Speciation of Cr, Cu and Ni in coastal sediments of Hong Kong was stud ied by the sequential extraction scheme of Tessier et al, (1979). Surf ace sediment samples were retrieved from eleven sampling points locate d in Victoria and Tolo Harbours. Multivariate analysis of the speciati on data revealed significant differences in the speciation patterns am ong metals, and between the two water bodies. Speciation data for labi le Cr and Ni showed distinct spatial patterns, which can be attributed to the difference in sediment condition of the two water bodies and t he similar solubility of their corresponding sulphide compounds. The s peciation pattern for labile Cu, on the other hand, appeared to be inf luenced by the differences in pattern and degree of pollution, Multipl e regression analysis of the speciation pattern of individual metals a gainst four sediment parameters (Eh, TOC, Fe-total and TS) revealed th at total sulphide content in sediment was the most important factor co ntrolling the distribution of metal species among various geochemical phases. (C) 1997 Elsevier Science Ltd.