Environmental safety assessment on chlorination by-products in brine discharged from desalination plant

Concentration analysis was performed on five chlorination by-products (chloral, dichloroacetic acid, trichloroacetic acid, 2,4,6-trichlorophenol, and pentachloro-phenol) present in the brine discharged from desalination project of Dagang New Spring Co., Ltd. Moreover, toxic effects (L(E)C-50) analysis was performed on three basic levels of aquatic organisms, namely, Scenedesmus vacuolatus, Daphnia magna, and Oncorhynchus mykiss. Based on the analysis, the quotient method from the technical guidance document on safety assessment of chemical substances by the European Union was adopted to assess the ecological risks of five chlorination by-products in the brine discharged from desalination plant. The results showed that the rates of detection of five chlorination by-products were 100%. The quotients of PEC/PNEC of chloral, dichloroacetic acid, trichloroacetic acid and pentachlorophenol were higher than 1. Among the four pollutants, we must pay more attention to chloral which environmental concentration in the brine discharged from desalination plant is 17 times higher than the no effect concentrations.