IMMUNOCHEMICAL METHODS TO MONITOR TOXIC SUBSTANCES IN HUMANS AND OTHER SPECIES

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A central problem to evaluating the risk posed by hazardous substances in humans and the environment is a lack of analytical techniques that can handle large sample loads with rapid turn around time. Immunoassays are finding their place among more established methods for measurement of toxic materials in the environment and have a predominant role in human monitoring. Advantages of immunoassays include speed of analysis, cost- effectiveness, sensitivity, specificity, applicability to a wide variety of compounds and adaptability to laboratory or field situations. This proposal has three objectives. The first is to develop rapid, inexpensive assays for hazardous substances and environmental degradation products. Lack of such assays affects site evaluation and limits the development of good models for groundwater movement, human exposure, and research on remediation systems. Several compound classes have been identified for assay development in this proposal. Triazine herbicides are good indicators of agricultural contamination. Assays previously development for parent and metabolic and environmental breakdown products will be used in monitoring studies. The pyrethroids, although of low mammalian toxicity, are toxic to other nontarget organisms such as fish and aquatic invertebrates. Low application rates, lead to very low (but potent) residues making this group of compounds particularly difficult to analyze. The impact of 2,3,7,8-tetrachlorodibenzodioxin on human and environmental health is still subject to debate and is a prime example of a compound for which analysis costs are extremely high. In collaboration with other investigators, assays for naphthalene, and nitronaphthalene will be developed. Heavy metals such as mercury, lead and copper have also been targeted. The second objective is to develop assays to assess human exposure and effect. These assays will be used to probe the mechanistic basis of toxicity. In collaboration with other workers markers for, and the mechanisms of; cellular toxicity will be addressed. Triazine mercapturate and p-nitrophenol (metabolites of some industrial intermediates, explosives and organophosphate insecticides) assays will continue to be validated. Newly proposed targets include a general assay for mercapturates as a marker of exposure to electrophiles, and protein bound species of naphthalene (an example of a target that may be specifically involved in cellular toxicity). Our third objective is the application of new immunochemical technologies to environmental field. The first techniques will interface immunoassay with classical analytical procedures such as utilizing antibodies for affinity separation and cleanup. Use of expert systems in technology transfer will be evaluated. Statistical considerations to address multianalyte problems will be developed. New reporter molecules (such as near IR fluorophores) to improve sensitivity and more robust enzymes to improve shelf life and portability will be evaluated. Finally training and support of other investigators in the use of immunoassay will be provided in collaboration with the Training Core.