Precursors for brominated haloacetic acids during chlorination and a new useful indicator for bromine substitution factor

Brominated haloacetic acids (HAAs) are much more cytotoxic and genotoxic than chlorinated one, yet little information is available for their organic precursors. In the present study, 8 water samples were collected in East China: 2 from lakes, 2 from rivers, 2 from reservoirs, a well and a mountain spring. Dissolved organic carbon (DOC), UV absorbance at 254 (UVA), specific UVA (SUVA) and chlorophyll a (Chl-a) were determined in raw water samples; formation of 9 HAA species as well as bromine substitution factor (BSF) were measured in chlorinated water samples. Results showed that water samples located in city generally contained higher levels of DOC (6.4–12.2mg/L) and UVA (0.124–0.194/cm), while those in the country side, low DOC (2.4–5.9mg/L) and UVA (0.061–0.109/cm) levels were observed. Negative relationship (p