ASSESSMENT OF TRACE-METAL TOXICITY USING MOLECULAR, PHYSIOLOGICAL ANDBEHAVIORAL BIOMARKERS

Laboratory-based assessments of the potentially damaging effects of tr ace metals in the natural environment are difficult to validate. This is a consequence of the diverse factors which in situ affect metal bio availability and the susceptibility of organisms to trace metal toxici ty. For several years, biomarkers (biochemical responses to contaminan t exposure) have been measured in the tissues, body fluids and excreta of a range of organisms to signal chemical exposure. More recently, h owever, the biomarker concept has been extended to include physiologic al and behavioural indices of both pollutant exposure and effect. In t his paper, a contemporary biomarker approach is outlined and new techn iques are described for measuring physiological and behavioural parame ters. In particular, biomarkers which indicate changes in Darwinian fi tness are discussed. Protocols are outlined concerning how simultaneou s measurements of molecular, physiological and behavioural biomarkers might be utilized in biological impact assessment of trace metals (and other pollutants). The potential use of biomarkers as laboratory scre ening tools and in bioremediation is also addressed.