How can we quantify and manage the impact of chemical pollution in the oceans?

Summary

Chemical pollution is ubiquitous in the world’s oceans and affects marine organisms. Pollutants in marine ecosystems include trace metals and organic pollutants such as pesticides, industrial chemicals, pharmaceuticals and personal care products, household chemicals, chemicals released from transport and chemicals associated with solid waste or effluents. The substances of major concern are persistent, bioaccumulative and/or have high or specific toxicity to marine organisms. Although the extent to which contaminants accumulate in organisms is clearly important, not least from the perspective of human consumption, the relationship between the concentration of one or more contaminants in tissues of an organism and health impact is not straightforward. To quantify the impact of chemical pollutants on marine organisms there is therefore a need to quantify their toxicity in the field. Chemical pollutants are known to cause effects on populations of marine organisms, e.g. endocrine disruption caused by the antifouling agent tributyltin in gastropods, reproductive failure in Baltic grey seal (Halichoerus grypus) and in European killer whale (Orcinus orca), the latter two associated with accumulation of polychlorinated biphenyls, PCBs. Important mechanisms of toxicity in marine organisms are carcinogenicity, genotoxicity, neurotoxicity, immunotoxicity, cardiotoxicity, endocrine disruption, reproductive toxicity and developmental toxicity. Methods to quantify carcinogenicity, genotoxicity, neurotoxicity, endocrine disruption, reproductive toxicity and developmental toxicity have to varying extents been included in monitoring programmes in European countries over the past decades. The methods in use have been chosen for their ability to distinguish between effects from contaminant exposure and the influence of other environmental processes. For most of them, there is an understanding of the mechanism of toxicity and the relationship between exposure and response is known. Over the past two decades, ICES working groups have developed a list of recommended methods, as well as criteria by which to assess data for the different methods and species. In parallel, activities have been established to ensure the quality and consistency of effect data from national and international monitoring programmes. The range of organisms used in monitoring programmes does not represent the full marine biodiversity. Progress has however been made to allow intercomparison of effect responses between species through developing species-specific assessment guidelines. Society needs to know the extent to which chemicals affect the oceans. New substances, for which there are no or limited effects data, are continuously being introduced, and a combination of methods will need to be used to identify and quantify health impacts caused by chemical pollutants. The following are recommendations for national and international monitoring programmes. 1. Full adoption of the ’biological effects methods’ monitoring approach within the integrated chemical-biological monitoring and assessment framework for accurate and realistic assessment of chemical pollution and its impacts, including the effects of chemical mixtures. 2. Inclusion of robust monitoring methods that quantify the most important toxicity mechanisms: carcinogenicity, genotoxicity, neurotoxicity, immunotoxicity, cardiotoxicity, and endocrine disruptiony. 3. Develop and implement quality assurance programs and intercalibration exercises to ensure comparability of data between laboratories, and to promote free accessibility of data. 4. Continue to bring in new evidence of biological effects of chemical pollution into national and international regulatory frameworks.