Heavy Metal Pollution In Jinzhou Bay And Risk Assessment

Jinzhou Bay is a semi-enclosed sea facing ocean, and the dilution rate of pollutants is far less than the admission rate characteristics since its hydrological conditions of the geochemical characteristics. Several large enterprises distribute around Jinzhou Bay coastal,which includes Huludao Zinc smelting plants,a historical pollution source,and they pour large quantities of wastewater containing heavy metals continuously to the gulf. Heavy metals are particular concerned for their highly toxics, persistence, bio-magnification and other characteristics.In August 2009, 20 surface water samples, 20 surface sediment samples collected from Jinzhou Bay and 35 sediment samples in south of Huludao were determined with FAA, AFS, CVAFS,etc.. The water samples were filtered with 0.45μm cellulose acetate membrane and the sespended particulate samples were collected at the same time. Heavy metals dissolved in seawater, absorbed in particulate and sediments were measured and the extent, characteristics, influence factors and the sources of heavy metals were analysed. Finally,comprehensive assessment on pollution in Jinzhou Bay was taken.The results show that concentration of heavy metals in seawater of Jinzhou Bay is much higher than the background value. The distribution of Cd and Cu, Zn and As are similar, liqule performance in a low concentration level appeared, which suggest a same source of Cu, Pb, Zn, Cd and As, while some other elements impact them respectively. Heavy metals dissolved in seawater and particulate heavy metals act with no obvious correlation: dissolved Cu, Zn, Cd, As are higher than those suspended particles, but Hg content is almost the same in the two phases, while Pb content is lower in seawater than in the suspension.The concentrations of Cu, Pb, Zn, As, Hg and MeHg are highest in southwest and northwest of Jinzhou Bay surface sediments, and decrease towards to the mouth of the gulf, showing the impact of land-based pollution. Main factor of Cr in surface sediments is natural sources, what is less influnced by human impact. Compared with other gulf inboard and abroad, heavy metal content in Jinzhou Bay is on a higher pollution level. The results of EF also show serious heavy metal pollution in Jinzhou Bay, especially mercury and methylmercury polluted most seriously. Huludao southern area is also subjected to certain heavy metals, while it is limited impacted by Jinzhou Bay heavy metal pollution.We use geo-accumulation index method, potential ecological risk assessment method and Hakanson evaluation based on triangular fuzzy numbers to evaluate the heavy metal pollution situation of Jinzhou Bay respectively. The results show that Jinzhou Bay exist high potential ecological risk, of which the primary pollution is mercury. And the Hakanson evaluation based on triangular fuzzy numbers is better among the 3 metheds above.