ABSTRACT
References ............................................................................................................. 252
Concerns over the contamination of water by pesticides generally arise from two scenarios, that is, concern over human health risks when water (e.g., groundwater) is used for drinking and concern over ecotoxicological effects when nontarget organisms (e.g., aquatic organisms and amphibians) are exposed to water in their habitats. Both the European Union (EU) and the United States have adopted stringent limits for pesticide presence in drinking water. For instance, EU regulations for drinking water quality set a limit of 0.5 mg=L for the sum of all pesticides and 0.1 mg=L for each compound. However, when acute or chronic toxicities or other ecological effects (e.g., bioaccumulation) are implied, water quality limits can be much lower than those for drinking water. For instance, in the total maximum daily loads (TMDL) established for diazinon and chlorpyrifos for a watershed in Orange County, California, the numerical targets for diazinon were set at 80 ng=L for acute toxicity and 50 ng=L for chronic toxicity, and those for chlorpyrifos at 20 ng=L for acute toxicity and 14 ng=L for chronic toxicity [1]. Regulatory requirements such as these have driven the development of increasingly more sensitive and rigorous methods for the analysis of pesticides in water.
