Application of immunological methods for the determination of environmental pollutants in human biomonitoring. A review

Human biomonitoring (HBM) is gaining increasing popularity in occupational and environmental health in order to assess individual chemical exposure. It involves the determination of an exposure marker such as a parent chemical and/or its metabolite(s) in selected tissues, expired breath, body fluids such as blood, or excreta. HBM can provide accurate information on absorption resulting from all routes of exposure. Because of the complexity of biological samples, in many cases tedious extraction and clean-up procedures are necessary to isolate analytes for classical wet chemical and instrumental analysis. In the clinical laboratory practice a modern approach is the use of immunochemical methods (immunoassays). These methods proved to be sensitive, fairly simple, and cost-effective alternatives or supplementations to existing highly sophisticated analytical methods. An increasing supply of commercialized immunoassay kits for environmental contaminants such as pesticides and industrial chemicals can be obtained. This paper reviews the application of immunochemical methods for the determination of environmental chemicals as exposure markers of internal dose in biological samples of human origin only. Applications have been reported for pesticides and trace contaminants. Both radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) formats have been applied, making use of polyclonal and monoclonal antibodies. Most of the reviewed methods are adequately sensitive for HBM. Validation of immunoassay performance is frequently made by intercomparison tests or fortification of samples. Usually, more polar analytes could be measured with reduced or no sample preparation. Especially with hydrophobic chemicals such as dioxins and PCBs extraction and sample clean-up were necessary to reduce interferences by matrix constituents. Only few assays have been applied to the measurement of pollutants in samples of occupationally or accidentally exposed human beings.