Due to its size and variety of sources, the characterization of microplastic is even more complex than for large plastic debris. There are two types of microplastics particles: those which have been intentionally made (primary sources) and those that result from fragmentation and weathering of larger objects (secondary sources; GESAMP, 2015; Thompson, 2015; RIVM, 2014). For microplastics originating from primary sources it may be possible to identify the specific source and, therefore, identify mitigation measures to reduce their input into the environment (GESAMP, 2015). Small plastic particles, within the microplastic size class, are created for items such as personal care products (it is estimated that users of facial scrubs in the United States may be responsible for the discharge of 263 tonnes per year of polyethylene microplastic; Napper et al., 2015) or as abrasive media for cleaning applications. They also result from the unintentional release of intermediate plastic feedstock (i.e. pellets, nurdles or mermaid tears) and occur as by-products of production or other processes. The latter includes probably the largest variety of sources – from particulate emissions from industrial production or maintenance of plastic or plastic-based products, to the release of dust and fibres, to the wear and tear on any plastic products during normal use. This includes particles made by cutting, polishing or moulding during the production of a plastic-based product, emissions during application or maintenance of plastic-based paint, fibres released from synthetic textile products during washing, or rubber particles released from the wear of tyres on roads.
From collection: Marine Litter Vital Graphics
GRID-Arendal and Maphoto/Riccardo Pravettoni