Multi-level modelling of chlorination by-product presence in drinking water distribution systems for human exposure assessment purposes.
During drinking water treatment and distribution, chlorine reacts with organic matter occurring in water to form various chlorination by-products (CBPs) such as trihalomethanes (THMs) and haloacetic acids (HAAs). This paper presents the occurrence of THMs and HAAs in different water distribution systems (DS) of the same region and their modelling for exposure assessment purposes. This study was conducted in eight DS supplying chlorinated water to the population of Québec City, Canada. These systems differ in type of water source (i.e. surface, ground or mixed water), in treatment applied at the plant, and in size and structure of the DS. Two spatio-temporal databases for THMs and HAAs were implemented, one for model development and the other for model validation. The analysis of the data demonstrates significant seasonal and spatial variations of these compounds. A multi-level statistical modelling approach was applied to estimate the ranges for occurrence of THMs and HAAs in the eight DS (i.e. a single model for the study region for each CBP species). The modelling approach integrates available or easily measurable parameters. For both THMs and HAAs, a two-level model considering a sampling-site random effect was selected among various models initially developed. The model capacity for estimating the presence of THMs and HAAs in drinking water and its usefulness for exposure assessment purposes in the studied region was demonstrated.
Legay
Christelle
C
École supérieure d'aménagement du territoire de l'Université Laval, Pavillon Antoine Savard, Université Laval, Québec City, Québec, Canada, G1K 7P4.
Rodriguez
Manuel J
MJ
Miranda-Moreno
Luis
L
Sérodes
Jean-Baptiste
JB
Levallois
Patrick
P
D019342:Acetic Acid / Q000032:analysis; D017606:Chlorine Compounds / Q000032:analysis*; D004202:Disinfectants / Q000032:analysis*; D004781:Environmental Exposure / Q000032:analysis / Q000706:statistics & numerical data*; D005618:Fresh Water / Q000737:chemistry; D054879:Halogenation; D006801:Humans; D008956:Models, Chemical; D012621:Seasons; D022882:Trihalomethanes / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification; D014881:Water Supply / Q000032:analysis* / Q000706:statistics & numerical data
D017606:Chlorine Compounds; D004202:Disinfectants; D022882:Trihalomethanes; D014874:Water Pollutants, Chemical; D019342:Acetic Acid