Microplastics in the Oresund Region of the Baltic Sea - sources and effects

Sammanfattning: Plastic production is only increasing, and it‟s not showing any signs of slowing down. Microplastics are particles smaller than 5 mm, either produced intentionally, or created from items being withered into small particles. Microplastic contamination in marine environments is higher closer to cities, and most of the plastic litter eventually ends up in the oceans. Microplastics have been found in habitats all over the planet however, and are a huge environmental concern. This literary review study aims to assess the current knowledge concerning terrestrial sources of microplastics, and possible effects of microplastics in a marine environment. Specifically this study will focus on the Oresund, a shallow strait, in-between Denmark and Sweden, two densely populated areas. The literature reviewed in this study indicates that over 1100 tonnes of microplastics could come from the Swedish coastline and into the Oresund. Several major sources and pathways were identified: littering, artificial turfs, roads, runoff, wastewater treatment plants (WWTPs) and wastewater sludge. Most microplastics entering into WWTPs get caught in the wastewater sludge. A percentage. however escapes into water courses leading to the Oresund. The filtered out microplastics get retained in the waste sludge, which is spread on agricultural soils. Soils adjacent to Oresund receive approximately 139 tonnes microplastic via waste sludge every year. Trafficated roads in the Oresund region yearly release 798 tonnes of microplastic from tyres and markings, and artificial turfs release 145 – 248 tonnes of microplastic. In Oresund microplastics can be consumed by plankton, molluscs, echinoderms, crustaceans and vertebrates. Microplastics impact the entire ecosystem, proving toxic and lethal to many filterfeeders and disruptive and damaging to fish. Via Oresund, which also functions as a nursery to nearby fish populations, microplastics can negatively affect adjacent regions, but more research is needed to fully understand the potential effects of microplastics throughout Oresund.