Use of biomarkers in environmental monitoring

Using specific examples, this paper discusses several key issues associated with the use of biomarkers, which could influence their effectiveness and usefulness. First, there are few biomarkers that are specific enough to allow an identification of the precise nature of environmental stressors. Second, biomarker studies conducted at molecular or subcellular levels tend to be more repeatable and predictable, but their ability to predict significant biological effects is limited. In contrast, biomarkers at physiological, organismic or higher levels are usually more ecologically relevant, but slower to respond and more difficult to detect. Third, some organisms have the ability to repair damage induced by initial toxic insults and make adjustments to their biological responses, thus increasing the chance of false negatives. Therefore, the selection of an appropriate biomarker for use under specific ecological circumstances will be a compromise that is determined by the precise question(s) asked and cost-benefit considerations. (C) 2009 Elsevier Ltd. All rights reserved.