Microplastics: Occurrence, effects and sources of releases to the environment in Denmark

This report contains a review of existing knowledge on issues related to contamination by micro-plastic with a focus on the use and release of micro-plastics in Denmark and the occurrence of micro-plastics in the surrounding waters. Micro-plastic defined as small plastic pieces of 1µm to 5 mm. Micro Plastics are detected in organisms at all levels of the marine food chain as well as in water and sediment. There are potentially three types of adverse effects of the micro-plastic: (1) physical effects related to the intake, (2) toxic response by the release of hazardous substances in the plastic and, (3) toxic reaction to the pollutants which are adsorbed to micro plastic. These effects are shown in laboratory experiments but not proven to occur in the environment. Although the majority of the micro plastics in the waste water end up in the sewage sludge, wastewater treatment plants are important potential sources of emission of the micro-plastics in the ocean. The most important sources of release of micro-plastics to the environment are tires, paints, road markings, textiles, etc. The report estimates that only minor significance to micro plastic used directly in certain products (for example, in cosmetics or for use in blowing agents).