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Genotoxicity of Swimming Pool Water and Carcinogenicity of Drinking Water
Citation:
DEMARINI, D. M. Genotoxicity of Swimming Pool Water and Carcinogenicity of Drinking Water. Presented at Departmental Lecture, Biology Department, University of Pisa, Pisa, ITALY, September 28, 2011.
Impact/Purpose:
Collectively, these studies indicate that a sub-population with the "at-risk" genotype and who are exposed to the brominated THMs and halo-acids in disinfected water primarily via the dermal/inhalation routes have the potential for increased risk for bladder cancer.
Description:
Among the 11 disinfection by-products (DBPs) in drinking water that are regulated by the U.S. EPA, (a) 2 DBPs (chloroaceticacid and chlorite) are not carcinogenic-in either of2 species; (b) chlorite is not carcinogenic in 3 rodent assays and has never been tested for genotoxicity; (c) 1 DBP (bromoacetic acid) has never been tested for carcinogenicity; (d) 2 DBPs, chloroform and trichloroacetic acid, are carcinogenic via nongenotoxic mechanisms; (e) 6 DBPs have significant genotoxicity data gaps; and (f) 5 DBPs have been assessed as possible or probable human carcinogens. Among 74 unregulated DBPs, 29 that occur at::;1 ug/L levels are genotoxic; and another 14 that occur at this level have no toxicological data except for 2, which are carcinogenic. The toxicity ofhalogenated DBPs is iodo > bromo> chloro, and 50% ofthe organic carbon and organic halogens ofdrinking water are not yet chemically characterized. A recent case-control bladder cancer study in Spain showed that the 28% ofthose who used water containing >49 ug/L ofthe 4 trihalomethanes (THMs) combined and who had a specific genotype (GSTTl + and aSNP in GSTZ) had a 6-fold risk for bladder cancer. Additional studies have found that dermal/inhalation exposure to DBPs via swimming in a chlorinated pool for 40 min produced micronuclei in the blood and mutagenic urine that were associated with the concentration ofbrominated THMs (not chloroform) in exhaled breath. Collectively, these studies indicate that a sub-population with the "at-risk" genotype and who are exposed to the brominated THMs and halo-acids in disinfected water primarily via the dermal/inhalation routes have the potential for increased risk for bladder cancer. [Abstract does not necessarily reflect the policy ofthe U.S. EPA.]