CLiP South Africa Microplastics in biota 2019

notPlanned

The Commonwealth Litter Project (CLiP) supported Belize to take action on plastics entering the oceans. The assessment of microplastics in biota was part of the action plan to define scientific baselines for future monitoring purposes and comparison. Samples of anchovies (Engraulis encrasicolus, 178 specimens), redeye round herring (Etrumeus whiteheadi, 188 specimens) and sardines (Sardinops sagax, 227 specimens) were collected during the 36th Pelagic recruit survey in 2019 carried out on board of the R.S. Africana by the South African Department of Agriculture, Forestry and Fisheries (DAFF). Samples were fished in an inshore area along the SA coastline limited by the Orange River mouth (West Coast) and George (South Coast) and divided in seven areas (strata). In the lab, stomachs were removed, rinsed and chemically digested by a 30 percent KOH:NaClO solution with an incubation period of 24 hours at 40 degrees centigrade. All samples were then filtered, stained with Red Nile dye and a digital image was acquired through a microscope. Number of particles was counted and corrected for particles count in blank samples. Visible particles were analysed using ATR-FT-IR to identify polymer composition, comparing their spectrum to a polymers library. ATR-FT-IR is the attenuated total reflection Fourier Transform infrared spectroscopy. A Thermo Fisher Scientific Nicolet iS5 ATR-FTIR with an OMNIC software (version 9.9.473) was used and polymers were identified based on the percentage match of IR spectra to a polymer library. Only spectra matched greater than 70 percent were accepted. Spectra were collected in the range 4000 – 650 1/cm at a resolution of 4 1/cm.