CLiP Vanuatu Microplastics in biota 2018

notPlanned

The Commonwealth Litter Project (CLiP) supported Solomon Islands to take action on plastics entering the oceans. The assessment of microplastics in seawater was part of the action plan to define scientific baselines for future monitoring purposes and comparison. Samples were acquired in different ways: tuna stomachs were received from local game fishing; land crabs were bought from the main food market in Port Vila; reef fish (mix of species) was collected with gillnets from local fishermen around the island. In the lab specimens were taxonomically identified and their digestive tracts were removed and weighted. For large stomachs, visible particles >5mm were removed. Stomachs content was then rinsed and chemically digested by a 30 percent KOH:NaClO solution with an incubation period of 24 hours at 50 degrees centigrade. Small stomachs (and crab digestive traits) were digested whole with a 30 percent KOH:NaClO solution with an incubation period of 3 days at 50 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 particle 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.