The ecotoxicological impacts of microplastics on marine organisms, including species providing a source of food

Sammendrag

There is no doubt that wildlife is contaminated with microplastic (MP) debris. Several research papers demonstrate this in a wide range of marine species from most trophic levels (pelagic and benthic). Still, there is much less scientific evidence regarding effects from this contamination, especially in organisms relevant to the seafood industry and human consumption. Whilst laboratory experiments have provided some evidence of sub-organismal impacts from microplastic debris, there are still relatively limited studies and even fewer that can be considered ecologically relevant. Moreover, studies regarding impacts to species relevant to the seafood industry are especially limited and have typically focused on benthic invertebrates (e.g. shellfish). Some recent studies have shown MPs are ingested and can elicit negative effects in marine mussels (Mytilus edulis), marine oysters (Crassostrea gigas) and in the freshwater fish (Oryzias latipes). The role of MPs as vectors for transporting known environmental pollutants (e.g. persistent organic pollutants (POPs) and metals) has also been shown to be of significance in fish. Due to the current weight of evidence, there remains a need to address a number of knowledge gaps concerning effects from MP including (i) potential effects of MPs on aquatic (marine and freshwater) species at different life stages, including those providing a food source for humans, (ii) determination of MP uptake and internalisation (e.g. across the gut wall) and potential for trophic transfer, (iii) understanding the role of MPs as vectors for exposure and bioaccumulation of sorbed persistent organic pollutants and metals already present in the environment, (iv) the role of associated additive chemicals on the potential effects of MPs to aquatic species, and (v) identification of specific modes of toxic action for MPs and their relationship to those of conventional marine pollutants. A small number of projects recently funded under the European Union Joint Programming Initiative on Oceans (JPIO) are attempting to address some of these knowledge gaps and a project recently funded by the Norwegian Research Council is specifically looking at the impact of MPs and POPs associated with MPs on the commercially important Atlantic cod (Gadhus morhua). However, these ongoing studies will not answer all the necessary questions, and therefore it will be important to align international activities and further support research to address these knowledge gaps.