[Distribution Characteristics and Health Risk Assessment of Heavy Metals in Surface Water Around Electroplating Factories].

To investigate the distribution characteristics and the human health risks of heavy metals in surface water samples, 30 samples were collected around electroplating factories of Machong, Shatian, Humen, Changan and Dalingshan towns in Dongguan city, 8 heavy metals(As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) contents were measured and analyzed by using multivariate statistical analysis method and human health risk assessment model. The results showed that the maximum concentrations of Cr, Pb and the average concentration of Hg exceeded Environmental Quality Standards for Surface Water(GB 3838-2002, Grade Ⅲ), the concentrations of Cr, Cu, Hg, Ni, Zn and Pb during rainy season were all higher than that those during dry season. Multivariate statistical analysis indicated that Cd, Cr, Cu, Ni and Zn mainly originated from the contaminated electroplating factories, Pb and Hg were mainly affected by the traffic sources, and As was significantly correlated with natural sources. Health risk assessment result of surface water indicated that heavy metal pollution would lead to high health risks especially for children, and the health risks of heavy metals through drinking pathway were 2-3 orders of magnitude higher than the values caused by dermal contact pathway. Moreover, carcinogenic risks caused by Cr and As were higher than the maximum allowance levels (5×10-5 a-1), and non-carcinogenic risks of the heavy metals (10-10-10-7 a-1) decreased in the order of Pb > Ni > Cu > Hg > Zn, which were 4-5 orders of magnitude lower than the maximum allowance levels.