title: Considerations for improving the accuracy of exposure to disinfection by-products by ingestion in epidemiologic studies.
abstract: Disinfection by-product (DBP) exposure characterization studies are often based on the analysis of a limited number of samples collected from a distribution system (DS) in which DBP levels are variable over time and space. A compositing technique was developed to simplify the sample collection procedures for integrating over temporal variations in DBPs measured in terms of trihalomethanes (THMs), haloacetic acids (HAAs), and total organic halogen (TOX). Over the course of 5 days analysis, the single composited sample was within 94-100% of the average THM concentration in all grab samples, 92-105% of HAAs, and 130% of the TOX concentration. Additionally, temporal variability factors such as timing of sample collection and the handling of tap water prior to consumption were found to influence DBP levels in consumers' drinking water. Included in our study of home water use are the effects of boiling which removed up to 98% of THMs and point of use (POU) devices which all showed DBP removal but differed depending on the device used. These factors should be taken into consideration in DBP exposure characterization for epidemiologic studies.
authors.affiliation: Department of Environmental Sciences and Engineering, University of North Carolina, School of Public Health, Rosenau Hall, South Columbia St., Chapel Hill, NC 27599-7431, USA. howard_weinberg@unc.edu
authors.forename: Howard S
authors.initials: HS
authors.lastname: Weinberg
authors.forename: Vanessa R P J
authors.initials: VR
authors.lastname: Pereira
authors.forename: Philip C
authors.initials: PC
authors.lastname: Singer
authors.forename: David A
authors.initials: DA
authors.lastname: Savitz
mesh_terms: D000085:Acetates / Q000032:analysis; D004203:Disinfection; D004326:Drinking; D004781:Environmental Exposure; D004784:Environmental Monitoring / Q000379:methods*; D016021:Epidemiologic Studies; D005374:Filtration; D006219:Halogens / Q000032:analysis; D006358:Hot Temperature; D013997:Time Factors; D022882:Trihalomethanes / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*; D014881:Water Supply / Q000032:analysis*
chemical_list: D000085:Acetates; D006219:Halogens; D022882:Trihalomethanes; D014874:Water Pollutants, Chemical