Each year vast amounts of plastic are produced worldwide. When released to the environment, plastics accumulate, and the plastic debris in the world´s oceans is of particular environmental concern. Whereas macro plastics are unpleasant due to aesthetical reasons and have potential to cause physical harm, micro plastics present a range of poorly characterized chemical and ecological hazards. Since the early 1980´s the level of micro plastics floating in the world´s oceans has increased by approximately one order of magnitude.
This project will investigate the hypothesis that plastic is a source of low-molecular weight hydrocarbons and other organic chemicals to the environment, and that chemicals liberated from plastic may be hazardous to the marine ecosystem. Environmental hazards posed by chemicals liberated from plastic debris by leaching or degradation in the marine environment will be assessed by using laboratory experiments and computer modeling. Plastic debris collected from the surface of the Baltic Sea, and model plastic materials will be artificially aged in laboratory experiments designed to simulate years of photochemical, oxidative, and mechanical breakdown in the environment. The mixture of plastic breakdown products, chemical additives and sorbed pollutants collected in these ageing experiments will be studied for persistence, bioaccumulation and toxicity (PBT) properties using laboratory tests and computer modeling. The persistence and bioaccumulation potential of the mixture will first be estimated by characterizing the physical-chemical properties of the mixture and applying models, then more refined simulation tests of biodegradability and/or in-vivo bioaccumulation in fish will be performed, as necessary. Toxicity testing of the chemical mixture will be carried out using subchronic tests with marine species representative of the Baltic Sea. Results of this research project will provide valuable information about the sustainability of current practices with respect to production, use and disposal of plastics in society.