Plastics and Microplastics: Impacts in the Marine Environment

Abstract

Accumulation of plastics and, more recently, microplastics, in the marine environment has become a global concern. Plastics are highly durable materials and this persistence coupled with increasing emissions to the environment has resulted in a wide-scale accumulation from shallow waters to the deep sea. However, it is important to recognise that plastic debris is a highly heterogeneous mix of different polymer types, sizes, shapes and sources, and all of these factors influence the type and probability of impact. A small proportion of these items is sufficiently large and they can be visualised by satellites from space, but it is now recognised that the most abundant size category are microplastics. Indeed, many scientists consider there will be even greater accumulations of plastic particles in the nano size range, but such particles are currently beyond the limit of analytical detection. There is clear evidence of impacts on wildlife, as well as economic harm, and there is growing concern about the potential for effects on human well-being. Over 700 species of marine organism are known to encounter plastics in the environment with clear evidence of physical harm from entanglement and ingestion. In addition, there is concern that plastics may present a toxicological hazard because they can transfer chemicals to organisms if ingested. However, there is currently little evidence that plastics provide an important vector for chemicals to wildlife compared to other pathways. There is also emerging evidence that plastic debris could have impacts on assemblages of organisms altering ecosystem processes. Despite this clear evidence of harm it is also clear that plastics as materials bring numerous societal benefits; however, unlike many of the challenges currently facing the ocean, the benefits of plastics could largely be achieved without emissions to the environment. In our view the solutions to this global environmental problem require a more responsible approach to the way we design, produce, use and dispose of plastics, so that we can realise the benefits of plastics without current levels of harm.