Development of a shower exposure model for benzene : background work for potential recommended update to the recently derived drinking water guidelines

Chloroform exposure was first identified in showers. Shower exposures were then examined for other volatile substances. This presentation discussed the development of a shower exposure model for benzene and included background work for potential recommended updates to the recently derived drinking water guidelines. Specifically, the presentation addressed the relevance for oil and gas sites and the influence on the drinking water guideline. Issues and limitation with Health Canada's Khrisnan model were identified. The advantages of an alternate model development were also presented. Model structure was examined with particular reference to how model exposures are modelled and the risk associated with taking showers with impacted water. Two general types of models were discussed, notably the simple model used to estimate exposures and the integrated physiologically-based pharmacokinetic model. The relevance of the drinking water guideline revision to the petroleum industry was addressed. It was concluded that future water quality guidelines will likely incorporate shower exposures. tabs., figs.