Risks of Disinfection Byproducts in Drinking Water: Comparative Mammalian Cell Cytotoxicity and Genotoxicity

Abstract

The drinking water community provides a public health service by generating of high-quality, safe, and palatable tap water. The disinfection of drinking water primarily employs chemical disinfectants. These disinfectants are oxidants that convert naturally occurring and synthetic organic materials, bromide, and iodide in the source water into chemical disinfection by-products (DBPs). DBPs are an unintended consequence of disinfection. Each disinfection method generates a different spectrum and distribution of DBPs; to date over 600 DBPs have been identified. Although reducing the public health risk of acute infection by waterborne pathogens, the unintended generation of DBPs poses a chronic health risk. DBPs represent an important class of environmentally hazardous chemicals that may carry long-term human health implications. A systematic in vitro mammalian cell analysis of the cytotoxicity and genotoxicity of emerging DBPs and related compounds has provided insight into their relative toxicities. These mammalian cell assays also allowed a comparison of the relative cytotoxicity and genotoxicity of the major DBP chemical classes. The impact of nitrogen-containing and iodinated DBPs was revealed by these cell toxicity assays. The use of alternative disinfectants generates new DBP compounds and alters the distribution of DBP chemical classes. The water supply community will be able to consider these factors when employing alternatives to chlorine disinfection. In addition, these data will be available to prioritize DBPs for future in vivo toxicological studies and risk assessment.