Contaminants in marine ecosystems: developing an integrated indicator framework using biological-effect techniques

Input of contaminants is an important pressure in most urbanized coastal areas, but establishing appropriate indicators of their presence and effects has been challenging. Such indicators would, at the very least, have to integrate chemical and biological data. One difficulty has arisen because the measurements provide information on different levels of biological organization (gene level up to community), although it is not obvious how this information could be conceptually linked. In addition, there are complicating factors, such as the differing ecological relevance of measurements, natural variation, confounding factors, and knowledge of background level or responses for each method. The challenge of how to take these issues forwards is discussed in light of current scientific thinking and of meeting international obligations. First, an integrated approach must be developed to using biological-effect techniques with chemical measurements, and second, assessment tools are required. Proposals for both of these have been initiated by ICES and OSPAR working groups and workshops. Concomitantly, steps have been taken to develop integrated assessment tools on a national basis. These show promise but highlight the difficulties of using biological-effect measures as indicators of ecosystem health.