The effect of boiling water on disinfection by-product exposure.
Chloraminated and chlorinated waters containing bromide were used to determine the impact of boiling on disinfection by-product (DBP) concentrations. No significant changes were detected in the concentrations of the dihalogenated haloacetic acids (DXAAs) (i.e., dichloro-, bromochloro-, dibromoacetic acid) upon boiling of chloraminated water, whereas the levels of the trihalogenated haloacetic acids (TXAAs) (i.e., trichloro- (TCAA), bromodichloro- (BDCAA), dibromochloroacetic acid (DBCAA)) decreased over time (e.g., 9-37% for TCAA). Increased DXAA concentrations (58-68%) were detected in the boiled chlorinated sample, which likely resulted from residual chlorine reacting with DXAA precursors. TCAA concentration was unchanged after boiling chlorinated water for 1 min, but a 30% reduction was observed after 5 min of boiling. BDCAA concentrations decreased 57% upon boiling for 1 min and were completely removed after 2 min of boiling, whereas DBCAA was removed after boiling chlorinated water for 1 min. Trihalomethane concentrations were reduced in both chloraminated (74-98%) and chlorinated (64-98%) water upon boiling. Boiling chloraminated water for 1 min reduced chloroform concentration by 75%. Chloroform was reduced by only 34% in chlorinated water after a 1 min boil, which indicates that simultaneous formation and volatilization of chloroform was occurring. Most of the remaining DBPs (e.g. haloketones, chloral hydrate, haloacetonitriles) were removed by at least 90% after 1 min of boiling in both samples. These data suggest that other mechanisms (e.g., hydrolysis) may have been responsible for removal of the non-volatile DBPs and further highlight the importance of examining individual species when estimating thermal effects on DBP concentrations.
Krasner
Stuart W
SW
Metropolitan Water District of Southern California, 700 Moreno Avenue, LaVerne, CA 91750-3399, USA.
Wright
J Michael
JM
D000085:Acetates / Q000032:analysis / Q000633:toxicity; D000097:Acetonitriles / Q000032:analysis / Q000633:toxicity; D002697:Chloral Hydrate / Q000032:analysis / Q000633:toxicity; D004203:Disinfection / Q000379:methods*; D006219:Halogens / Q000737:chemistry; D006868:Hydrolysis; D007659:Ketones / Q000032:analysis / Q000633:toxicity; D044366:Transition Temperature; D022882:Trihalomethanes / Q000032:analysis / Q000633:toxicity; D014867:Water / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
D000085:Acetates; D000097:Acetonitriles; D006219:Halogens; D007659:Ketones; D022882:Trihalomethanes; D014867:Water; D002697:Chloral Hydrate