Geochemistry of microplastics

Abstract

On global basis, 300 millions tons of plastics are produced annually. Half of them are single-use plastics. Some of them escape from land-based activities and discharged into rivers through surface runoff, and finally into the ocean. The amount of plastics entering into the ocean is estimated at several millions tons per year (i.e., 5 ~13 millions tons/y, Jambeck et al., 2015). During their movement or floating on the sea surface and/or stranding on beaches, they are usually exposed to UV radiation and get fragmented into smaller plastics (Andrady, 2011). Fragments get smaller and smaller and finally they become microplastics (i.e., plastics less than 5 mm in diameter; Fig.1, Fig.2). In addition to fragmentation of plastic products, there are several other origins of microplastics in marine environments, i.e., resin pellets, microbeads in personal care products, chemical fibers from synthetic textile, shavings from sponge of synthetic fibers, etc. Consequently, huge amounts of plastics (i.e., 5 trillions pieces or 270,000 tons of plastics, Cózar et al., 2014; Eriksen et al., 2014) are floating on world ocean. Geochemical significance and role of microplastics will be discussed on the talk.