Abundance and distribution of microplastics in the German bight – Do ships leave skid marks?

, Dibke Christopher, Fischer Marten, Scholz-Böttcher Barbara.

Microplastics (MP, particles from 1 µm to 5 mm) are a complex class of contaminants. They are highly diverse in polymer type with a multitude of potential sources and are ubiquitous pollutants in the marine environment. Here, abundance and distribution of MP are determined by its sources of entry and subsequent complex physical, chemical, and biological interactions. Mass related MP data provided by thermal methods enable polymer specific geospatial and/or temporal studies independent of any particle appearance or size. Data acquisition in defined regions gives insight into general horizontal and vertical MP composition and changes. Potential sources can be tracked and located within the area of interest. In this first mass related survey of MP in surface waters (2.5 m depth) of the German Bight, North Sea the spatial MP load, its potential sources and temporal variation were comprehensively examined. For this purpose the most relevant 10 consumer plastics were analyzed using Py-GCMS/thermochemolysis as an excellent method for qualitative and trace level polymer specific mass quantitative analysis [1, 2]. The overall MP concentration in surface waters of the German Bight ranges between 2 and 1400 µg m-³. Neither its concentration nor type distribution was homogenous. Besides meteorological and oceanographic conditions of substantial influence on spatial and temporal mass loads, this variability was attributed to the particulate nature of MP as well. While detected polymer distribution patterns of some areas were closely related to packaging waste others attracted attention by polymers closely related to marine (antifouling) coatings. First estimations of their abundance indicate that they as marine sourced MP invert the widely cited 80% terrestrial - to 20% marine based debris ratio for MP at least for the studied area. [1] Fischer M, Scholz-Böttcher BM. 2017. ES&T, 51, 5052–5060. [2] Fischer M, Scholz-Böttcher BM. 2019. Anal Meth, 11, 2489-2497

View online