Bioanalytical tools for monitoring polar pollutants

Bioanalytical tools offer some advantages over classical analytical techniques in terms of selectivity, sensitivity, short assay times, and reduced cost of analysis. This makes them promising for use in monitoring and screening of environmental pollutants for the future. The present review will present an overview of primarily enzyme- and immune-based assay techniques presently developed for environmental purposes. In most cases, the principle of these methods is based on the correlation between the toxicity of a target compound and a decrease in the activity of a biomarker such as an enzyme. Organophosphorus (e.g. paraoxon, parathion, fonofos) and carbamate (e.g. aldicarb, carbofuran) insecticides selectively inhibit cholinesterases and imidazolinones and sulfonylureas affect the enzyme acetolactate synthase. Triazine herbicides and some phenol derivatives reduce the activity of tyrosinase and dithiocarbamate fungicides (i.e. maneb, zineb) inhibit aldehyde dehydrogenase. Some toxic compounds have the property of reducing the intensity of certain natural processes such as photosynthesis and bioluminescence. Certain phenolic compounds are specific substrates for the enzymes tyrosinase and laccase, and non-specific for e.g. peroxidases and dehydrogenases. Based on the above properties, both electrochemical and optical methods for detection of pesticides and phenols have been developed and will be presented. Determination of environmental pollutants using immunoassays is a continuously growing area. The advantages offered by these methods are again improved specificity, sensitivity, reduced cost, and the possibility for analysing real samples without pretreatment in a shorter time period than with classical methods. The most suitable analytes for immunoassay developments were triazine- and phenoxyacid herbicides, but phenols and other classes of pesticides represent promising targets for the future and will be discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.