Plastics in marine environments are degrading into smaller and smaller pieces, and the fates and impacts of microplastics and are not well understood. Estimates of floating plastics in the ocean come up short compared to estimates of global plastic loads into the ocean. (Cite Jambeck and Eriksen et. al 2014.) One possible fate of microplastics deposition onto and integration into beaches. Beaches have long been used to monitor trends and composition of macroplastic marine debris, and in this report, the prospect of conducting similar studies for beach microplastics is explored through a case study at two beaches in Roskilde fjord. The first beach was sampled strategically as a preliminary test to optimize the sampling strategy for the final study. The final sampling strategy was stratified random sampling by beach zone, with samples collected from homogenized quadrats to a depth of 5 cm, in addition to one transect of one 15 cm core per zone. Abundance of microplastic fragments and fibers in different beach zones was examined using density separa-tion with a Sediment-Microplastic Isolation (SMI) unit with zinc chloride as a floata-tion medium at a density of 1.5 g/cm3. Thereafter, the samples were digested with hydrogen peroxide to minimize organic debris, and quantified as microplastics / kg dry weight using visual inspection with low-power microscopy. The inspection and analysis was primarily assisted by mechanical destruction tests and a burning test, but high-power microscopy and Fourier Transform Infrared Spectroscopy (FTIR) were also used to evaluate the chemical nature of the microplastics, and resolve other uncertainties. Lastly, a loss-on-ignition test for organic weight percentage was performed on the homogenized samples. Microplastics were found to be prevalent in all zones of both beaches with difference abundances, but these differences were deemed statistically insignificant based on a single-factor ANOVA analysis of variance. Both correlation analysis and regression analysis found a moderate as-sociation between microplastic abundance and organic matter weight percentage of the samples.
|Uddannelser||Basis - International Naturvidenskabelig Bacheloruddannelse, (Bachelor uddannelse) Basis|
|Udgivelsesdato||28 maj 2018|
- Nationalpark Skjoldungernes Land