AWWA WQTC56986

The objective of this study was to provide an improved exposure assessment for the reanalysis of two well-conducted, peer-reviewed epidemiology studies that reported an increased risk of bladder cancer associated with chlorinated drinking water and THMs in Iowa and Ontario. An improved exposure assessment would provide more complete information on THMs plus haloacetic acids (HAAs), including class sums and individual species, formed during chlorination and alternative disinfection processes. Because bladder cancer has a long latency period, up to several decades, historical DBP data (back to 1900 in Iowa and to 1940 in Ontario) were required for the reanalysis. Historical databases contain very limited DBP data, and there are no estimates for past DBP occurrence prior to the mid-1970s. Although THM data have been collected routinely since the 1980s, most utilities did not start measuring HAAs until the 1990s. Therefore, this research proposes that, through models and correlations, it is possible to estimate past DBP levels based on present trends and knowledge about changes in source water/treatment practices, in both the present and past. Such estimates can provide an improved exposure assessment for the reanalysis of epidemiology studies, such as the Iowa and Ontario studies. Includes 4 references, tables.

Product Details

Edition:

Vol. - No.

Published:

11/01/2002

Number of Pages:

9

File Size:

1 file , 270 KB