Abstract
The world has reached an era where the dominance of anthropogenic activity has impacted the environment unlike no other time in history which has led to unfavourable environmental phenomena such as the diminishing quality of freshwater. Amongst others, a prevalent contaminant that threatens freshwater resources which is causing grave concern worldwide is microplastic pollution, which is now ubiquitous in terrestrial, freshwater, and marine ecosystems. This research investigated the concentration, temporal variation, spatial distribution and fluxes of microplastic particles in an urban river located in Klip River catchment to identify the potential catchment characteristics which influence the patterns mentioned above. This study used microscopy to enumerate microplastic particles and observed microplastic particles in all of the selected monitoring sites with mean annual microplastic concentrations which ranging from 0.70 particles L-1 to 1.84 particles L-1. Furthermore, this study reported the fluxes between at 2.51 × 108 MP/y to 1.21 x 1010 MP/y accumulating as you move downstream the catchment. Seasonality proved to be a significant factor affecting the concentration in microplastic contamination as the wet season observed higher microplastics than dry seasons. The monitoring sites which were in close proximity of residential and industrial land cover observed the highest concentrations of microplastics whereas monitoring sites which were predominately covered by natural land cover observed lower concentrations of microplastic particles. Based on these results, it is evident that catchment characteristics such as seasonality, rainfall, land cover, runoff and the presence of wetlands are influential factors which significantly control the pervasiveness of microplastic pollution in urban river catchments.