03. ASSESSMENT OF HEAVY METAL CONTAMINATION IN WATER AND SURFACE SEDIMENTS OF THE BA CHE RIVER ESTUARY, BAI TU LONG BAY, QUANG NINH PROVINCE

Tóm tắt

Estuary sediments contain toxic heavy metals which can pollute coastal wetlands. Ba Che river estuary is a coastal wetland with an area of 2,844 ha, which is affected by wastes in Ba Che river water and aquacultures. In this study, the accumulation of heavy metals in the Ba Che river estuary was assessed based on the enrichment factor (EF), the geo-accumulation index (Igeo), and the ecological risk index (RI). Heavy metal concentrations were determined by the inductively coupled plasma mass spectrometry, after completing mineralization by microwave-assisted digestion. Results of the research, all heavy metals were detected in water samples with mean concentrations of As, Pb, Hg, Cd, Cr, and Zn in were range of 0.7-2.0; 0.7-2.2; 0.3-0.5; 0.2-0.6, 0.9-4.0; 4.3-13.9 µg/l; and in sediment were range of 4.01-11.24; 9.83-27.85; 0.42-0.46; 0.46-0.67; 4.73-18.25; and 42.49-129.17 mg/kg dry weight, respectively. Besides, the mean metal concentration in the water samples increased in the following order: Zn<Pb<Cu<As<Cd<Hg. Calculation of different ecological contamination factors showed that Hg is the primary contribution to ecological risk index (RI) origins from anthropogenic and urbanization sources.