ES&T GUEST EDITORIAL Drinking water contamination: Priorities for analysis of organics The ultimate aim of analyzing drinking water for organic contaminants is to provide qualitative and quantitative data that can be used to assess the potential for adverse health effects from consumption of the water. Because of the increasing sensitivity of analytical chemistry, the task of assessing the potential for human toxicity of all the trace organic contaminants in water is becoming unmanageable. Definitive judgments concerning the toxicity or lack of toxicity of these organic contaminants to humans can be made only from the results of animal tests or studies in human populations exposed to the compound(s) in question. To date, only the results of animal studies have been of value in assessing potential toxicity. The cost of evaluating the potential toxicity of each individual organic compound in finished drinking water would be prohibitive. Also, if we continue with our current approaches for determining the potential toxicity of these trace organics, we risk the inefficient use of limited resources. One solution would be to rank in a priority list the organic contaminants to be evaluated for potential toxicity. I propose that we concentrate initially on identifying and examining those compounds present in finished drinking water at concentrations >1 Mg/L. For those organic compounds in drinking water that have the potential to cause acute or chronic toxicity in humans, the concentrations at which there is concern almost invariably exceed 1 Mg/L. For example, the pesticide aldicarb, which has the greatest potential for acute toxicity of all the compounds currently identified in drinking water, does not pose a significant risk at a concentration of 1 Mg/L or less. For those compounds detected in drinking water that cause chronic toxicity, the concentration that poses a significant risk is almost always >1 Mg/L. For example, the World Health Organization considers concentrations of carbon tetrachloride, tetrachloroethylene, and trichloroethylene in drinking water in excess of 1 Mg/L to pose a significant risk. This finding is in agreement with the recent recommendations of the 0013-936X/83/0916-0113A$01.50/0
National Drinking Water Advisory Council of EPA concerning these and other compounds. The initial analyses should also be confined to the more lipid soluble compounds with molecular weights
