Plastic fragments can also come from the use of plastic particles as abrasives in ‘sandblasting’ and exfoliants in cosmetics (Barnes et al., 2009; Andrady, 2011), from spillage of pre-production plastic pellets and powders used for moulding plastic objects, as well as from plastic items deliberately shredded on board ships to conceal plastic waste in food waste (Barnes et al., 2009). These sources are known as primary microplastic sources, whereas secondary microplastics are those formed from breakdown of larger plastic material (Arthur et al., 2009). The relative importance of primary and secondary sources of microplastics to the environment is unknown and addressing this gap could help inform measures to mitigate and prevent microplastic pollution (Arthur et al., 2009).
