Analysing Microplastics Sinks and Sources from a typical Catchment area to the open Baltic
Microplastic pollution in the oceans is increasing worldwide. High concentrations found at the mouth of rivers suggest a substantial contribution of contamination from inland. To what extent is agriculture responsible for these inputs?
To date, microplastic research is mainly restricted to oceans. Studies are missing that elucidate the connections between contaminations across multiple ecosystems. Plastic tarps used in agriculture, or microplastic entering the field with application of sewage sludge and fermentation residues, can accumulate in the soil and erode into surface waters.
In the exemplary Warnow river catchment (Mecklenburg-Vorpommern), this collaborative project funded by the Federal Mistry of Education and Research will identify microplastic sources and sinks on land and in surface waters. The use of models will help quantify relevant pathways into the open Baltic. In a sub-project, the Thünen Institute approaches the aim to estimate spatial distributions of microplastics on fields and field margins and to identify pollution hot spots. Eventually these results will be used to infer potential mitigation measures.
In a first step, a land use analysis will identify areas that qualify for microplastic sources due to their historical land use. Remote sensing images, statistic data and expert information will be used amongst others. Then, we will analyse selected soil samples from the catchment area on their microplastic amounts and characteristics. This analysis serves as the basis to estimate microplastic amounts for the entire catchment area. The results will feed into a hydrogeological model that quantifies the pathways into surface waters.
What are the relevant sources and sinks of microplastic associated with agriculture?
Do non-agricultural sources, such as plastic litter in road side ditches, play a role?
How can input pathways be characterized, e.g., do lakes act as a sink?
8.2017 - 7.2020
Project status: ongoing