AWWA WQTC57175

This study utilized drinking water analysis and household surveys to address actual trihalomethane (THM) exposure conditions and to consider their potential impact in assessing human health risk. Total THM (TTHM) concentrations and coliform contamination were measured in distribution tanks and in household tap water in one region of the Mexico City Metropolitan Area (MCMA). The TTHM concentrations in the tanks and households ranged from 62 to 135 ug/L and from none detected to 142 ug/L, respectively. Total coliforms were found in one of the four tanks and in the tap water of four of 32 households; fecal coliforms were confirmed in the tank and in tap water from one of the homes. Household interviews were conducted to collect data useful for assessing population exposure. The survey results highlight the importance of measuring actual exposure in determining more realistic estimates of health risks due to TTHMs in drinking water because the default assumptions usually made would not be accurate nor complete. Such assessments could ultimately impact regulatory policy and water quality management, especially when comparing THM risk with microbial risk. In this region of the MCMA the greater concern was the presence of coliforms in one tank and in some of the households. Stronger pathogen control measures prior to water consumption are necessary in this area of the MCMA but can be done with consideration to control THM formation. An exposure assessment, followed by a risk analysis, can assist in evaluating the actual risk of THM exposure relative to bacterial contamination. Includes 19 references, tables, figure.

Product Details

Edition:

Vol. - No.

Published:

11/01/2002

Number of Pages:

13

File Size:

1 file , 330 KB