Plastic and Microplastic in the Environment. Группа авторов

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Plastic and Microplastic in the Environment - Группа авторов


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secondary sources. Primary MPs are produced in micro sizes, such as microbeads for personal care products and plastic resins. Secondary MPs are generated from the degradation of large plastics (Andrady 2011). Textile laundering facilities and sandblasting are other sources of MPs (Browne et al. 2011; Napper and Thompson 2016). The pollutants are washed down the drain along with wastewater and enters sewage systems, where they are too small to be removed by WWTPs and so end up in the river systems and finally in the oceans.

      1.2.1 Primary Sources

      1.2.1.1 Microplastics from Personal Care Products

      Source: Cheung 2016, p. 02 / With permission from Elsevier. (b), (c) Scanning electron microscopy (SEM) of microbeads utilized in cosmetic products

      Source: Napper 2015, p. 05 / With permission from Elsevier; Godoy 2019, p.06 / With permission from Elsevier.

      1.2.1.2 Microplastics from Plastic Resins

      Another major source of primary MPs are plastic resins (pellets or powders). The pellets or powder resin (≤ 0.5 mm) are generally cylindrical or disk shaped (Bergmann et al. 2015). These plastics are transported to factories for re‐melting and molding into a wide range of commercial plastic products. The plastics are released into the environment due to improper handling, such as accidents during transport or runoff from production processes.

      1.2.2 Secondary Sources

      1.2.2.1 Microplastics from Degradation of Plastic Debris

Photos depict (a) degradation and fragmentation of plastic under environmental factors; (b) and (c) the cracks seen at the surface are caused by photochemical degradation.

      Source: Ter Halle 2016, p. 15 / With permission from American Chemical Society.

Photos depict SEM of typical fibers: (a) polyester-cotton blend; (b) polyester; (c) acrylic.

      Source: Napper 2016, p. 03 / with permission from Elsevier.

      A pathway of primary MPs input to freshwater environments has been found through WWTPs and the utilization of sludge from WWTPs to agricultural lands. Previous studies depicted that 90% of MPs in domestic wastewater are retained within sludge (Magnusson and Norén 2014; Talvitie and Heinonen 2014). In Europe, sewage sludge is normally composted to produce agricultural fertilizer as well as dispose of the sludge to land. The EU countries apply about four to five million tonnes of sludge to agricultural lands, annually (Willén et al. 2017). MPs that cannot be removed in the treatment process will reach the freshwater environments via effluent (Horton et al. 2017). Another pathway of primary MPs could be from the release of industrial products or processes.

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