Mikroplast och reningsverk – en del av ett större miljöproblem

Sammanfattning: Microplastics are found in many different environments and they constitute a growing environmental problem. Although the studies into the subject are numerous, there are still several gaps in understanding the nature of the problem. There has been an increasing focus on microplastics from environmental protection agency’s around the world to identify the sources and pathways for the pollution, and the Swedish EPA has in a recent report addressed the lack of data for doing more accurate models and estimations on the microplastic problem. A known source for microplastic pollution is waste water treatment plants (WWTPs), which have been shown to receive microplastics from sources such as roads and washing of clothes. However, the data on microplastics in relation to WWTPs are limited to a few pilot studies and that along with the growing concern around the problem motivates more studies on the subject. The purpose of this study was to investigate microplastics in one step of the water treatment process at a Swedish WWTP in Lund. Water samples were collected at two different locations close to the WWTP and analysed in lab by filtering and microscopy. The results show that microplastic fibers were present at both locations and that smaller fractions, 20-300 μm, were present in a much higher concentration than larger fractions, >300 μm. Furthermore, the results indicate that there was a difference in concentration between the locations, meaning that some microplastics might be removed between the locations. The study shows that microplastics are indeed present in the studied WWTP, in line with results from similar studies, and that it is a source of microplastics to its recipient. Since the WWTPs is just one part of the microplastic pathway, further studies must be carried out to get a complete picture of this environmental problem, from the initial sources like roads and washing of clothes to the places were microplastics end up such as sediments and the sea.