Chlorination By-Products

Drinking water comes from natural sources in the environment, with naturally occurring disease-causing microorganisms. Because of this, water must be disinfected in order to be [Page 104]potable and safe for human consumption. However, common disinfectants may also react with naturally occurring components of the water to create by-products that can have cancerous or other health effects.

Drinking water sources typically derive from either surface or ground waters. Surface water has naturally occurring pathogens, which are biological agents, such as bacteria, that cause human diseases. Some of the most dangerous of these pathogens originate from the gastrointestinal (GI) tracts of mammals. When animals or humans defecate near surface water, the water may become contaminated with these pathogens, which causes illness when humans drink the water. In countries ...