Multivariate statistical relationships between routine water plant data and trihalomethane levels. Implications for studies of human health

Routine water treatment plant data were used to construct a mathematical/statistical model of trihalomethane formation during lime-soda ash softening. Chemical characteristics of the raw water, such as temperature and color, and several treatment parameters, including chlorine dose, were significant predictors for chloroform and total trihalomethanes. The pattern of prediction was notably different for the brominated species. The results of this preliminary study support the view that routine water plant data can be used to estimate retrospectively, and with accuracy, trihalomethane levels for past time periods in which only the routine plant data are available. Possible limitations of the approach and the prospects for improving epidemiologic health effects studies of trihalomethanes in drinking water are discussed.