Several analytical methodologies are available to monitor agricultural chemicals such as parathion in environmental samples and extracts from food products. In addition, methods are available to monitor some pesticides in samples of biological fluids. However, these methods are generally based on the use of sophisticated instrumentation and the expense and time involved make them generally unsuitable for broad-scale epidemiological studies. In addition, the available technology is not generally adaptable to nonlaboratory environments.In contrast, immunochemical techniques provide reliable detection of specific antigens, are cost-effective, and can be used by relatively unskilled individuals in nonlaboratory settings. Moreover, immunochemical reagents can be used to detect and quantitate in situ via immunochemical staining of residue accumulation in tissues at the cellular or subcellular level. Finally, immunochemical methods can be designed to detect specific antigens or whole families of related antigens. In this regard, immunochemical methods are uniquely suited for broad-scale screening studies. Therefore, it is proposed that several approaches be explored to develop assays for the immunochemical detection of pesticide residues using parathion as a test model. An innovative approach to this problem will include the use of liposomes and adjuvants to prepare the desired immunochemical reagents. These new methods will complement protein conjugation as a tool for antibody production against low molecular weight pesticide haptenes.National Institute of Environmental Health Sciences (NIEHS)