BIOCHEMICAL BIOMARKERS IN ECOTOXICOLOGY - SOME RECENT DEVELOPMENTS

Biochemical biomarkers measure the exposure of organisms to environmen tal chemicals. They can also provide measures of toxic effect, e.g. wh ere they are based on molecular mechanisms which underly toxicity. Ide ally, biomarkers should be sensitive, specific, simple to use and suit able for the assay of material obtained by non-destructive sampling pr ocedures (e.g. of blood). Recently, there has been encouraging progres s in the development of several different types of biomarker assays: ( 1) The measurement of inhibition of serum 'B' esterases to monitor exp osure of birds to organophosphorus insecticides. (2) The measurement o f DNA damage caused by aromatic hydrocarbons. DNA adduct formation has been studied using the P-32-postlabelling technique. Several other te chniques are currently under investigation. (3) The measurement of dis turbances to the transthyretin-retinol binding protein complex caused by a metabolite of 3,4,3',4',tetrachlorobiphenyl. (4) The measurement of precursors of clotting proteins in blood following the inhibition o f the Vitamin K cycle by anticoagulant rodenticides. Of these examples , the first is only a biomarker of exposure but the remaining three ex amples are, in principle, biomarkers of toxic effect since they all re present measures of molecular mechanisms which underly toxicity. Bioch emical biomarkers have considerable potential for measuring effects of chemicals under field conditions - especially where carefully selecte d combinations of them are used.