Small items of plastic under five millimetres in size are called microplastic. They are an important component of marine litter, being ubiquitous across all global marine environmental compartments.
To develop strategies for reducing plastic inputs into the ocean, it is essential to understand the distribution, degradation and transport of macroplastic (i.e. large plastic items) and microplastic particles. This report addresses these three topics, which are necessary for understanding the potential exposure of microplastic in the marine environment. Together with hazard identification, exposure is a fundamental component in conducting risk assessment.