Characteristics of microplastics in different media in Jiaozhou Bay, China

In the current global environmental problems, marine plastic pollution, ozone depletion and ocean acidification are included. With the development of research on microplastics, we have obtained important understandings on the temporal variation of the spatial distribution characteristics and the spatial variation of the temporal distribution characteristics of microplastics in China’s coastal waters. However, due to the complexity of microplastics features, the study of microplastic sources is in a relatively preliminary stage. Based on topographic features and chemical composition, an integrated index for microplastics complexity (MCI) was developed, and was applied in reflecting microplastics complexity in different media in Jiaozhou Bay. We compared the differences in microplastic complexity in wastewater treatment plants (WWTPs) and seawater, sediments and biota by in Jiaozhou Bay. MCI range from 0.35 to 57, with the average of 0.49 in wastewater in WWTPs. The MCI in zooplankton, which was 0.3 in average. The MCI in zooplankton is rather lower than that in the seawater, as zooplankton are so small as not to ingest large size particles of microplastics. The MCI of benthic shellfish was 0.46, which was higher than that in zooplankton, indicating that the complexity of microplastics in benthic shellfish were higher. The results of the study suggest that the value of MCI can be used for quantitative analysis of microplastic source apportionment. The MCI in wastewater in WWTPs, seawater, sediments, shellfish, and zooplankton showed the complexity of microplastic contamination in each phase and the connection between different media. Quantitative source apportionment is continuing to further promote the accomplishment of goal 14.1 in SDGs and decision support.