Research
The assessment of population exposure to chlorination by-products: a study on the influence of the water distribution system
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* Corresponding author: Manuel J Rodriguez manuel.rodriguez@esad.ulaval.ca
1 École supérieure d'aménagement du territoire, Université Laval, Pavillon Antoine Savard, Québec City, QC., G1K 7P4, Canada
2 Département de Génie Civil, Université Laval, 2917B Pavillon Pouliot, Québec City, QC., G1K 7P4, Canada
3 Institut National de Santé Publique du Québec, 945 Avenue Wolfe, Québec City, QC., G1V 5B3, Canada
Environmental Health 2010, 9:59 doi:10.1186/1476-069X-9-59
Published: 7 October 2010Abstract
Background
The relationship between chlorination by-products (CBPs) in drinking water and human health outcomes has been investigated in many epidemiological studies. In these studies, population exposure assessment to CBPs in drinking water is generally based on available CBP data (e.g., from regulatory monitoring, sampling campaigns specific to study area). Since trihalomethanes (THMs) and haloacetic acids (HAAs) are the most documented CBP classes in drinking water, they are generally used as indicators of CBP exposure.
Methods
In this paper, different approaches to spatially assign available THM and HAA concentrations in drinking water for population exposure assessment purposes are investigated. Six approaches integrating different considerations for spatial variability of CBP occurrence within different distribution systems are compared. For this purpose, a robust CBP database (i.e., high number of sampling locations selected according to system characteristics) corresponding to nine distribution systems was generated.
Results and conclusion
The results demonstrate the high impact of the structure of the distribution system (e.g., presence of intermediary water infrastructures such as re-chlorination stations or reservoirs) and the spatial variability of CBPs in the assigned levels for exposure assessment. Recommendations for improving the exposure assessment to CBPs in epidemiological studies using available CBP data from water utilities are also presented.