Title: Evaluation of the relationship between microplastic pollution and landuse in the Rur catchment in North Rhine-Westphalia, Germany
Author: Kareen Mirembe
Supervising Institution: IHE Delft - Institute for Water Education
Microplastic pollution is a potential threat to aquatic ecosystems which are under anthropogenic pressure. Therefore, the purpose of the study was to determine the relationship between microplastic abundance and landuse in Wurm, Inde and Upper Rur subcatchments. Surface water samples were collected using a pump sediment samples using a metal scoop from a total of 32 sites. The microplastic particles of 300 μm -1000 μm size range were identified using a stereomicroscope. A subsample of the particles identified were further analysed using a Raman spectrometer to determine the chemical composition. The total mean abundance of microplastics in surface water and sediments differed significantly and showed no distribution pattern within the Upper Rur and Wurm subcatchments (p<0.05). The significant spatial variation in the distribution of microplastics in surface water increased with a trend from Upper Rur (0 to 7 particles KL-1), Inde (0 to 13 particles KL-1) and Wurm (2 to 25 particles KL-1). There was a positive significant relationship between the total abundance of microplastics in surface water with agriculture and urban landuses. However, no significant relationship observed between the total abundance of microplastics in the sediments (p>0.05). The polymers spectra obtained for microplastics in sediment showed that: copper pthalocyanine polymer spectrum predominated in Upper Rur (43%), polyethylene spectrum (PE, 50%) was common in the Wurm. In Inde, cellulose nitrate (23%) and copper pthalocyanine (30%) were commonly recoreded. The findings show the widespread distribution of microplastic particles in all the subcatchments. The results suggest the need for policy response to the management and monitoring of microplastics in the Rur catchment, North Rhine Westphalia, Germany.