An assessment of land-based activities as inputs of microplastic pollution in South Africa’s aquatic environment: a case study of Durban Bay harbour and the Hennops River
Latcheman, Digambari Devi Sharma
Microplastics have been identified globally in a diverse range of environments. The extent of information on microplastic pollution in South Africa’s context is scarce and lacking. An investigation of microplastic pollution was conducted across the Durban Bay harbour in the KwaZulu Natal province and the Hennops River, Gauteng province in South Africa. Microplastics were detected in all surface water and sediment samples, with abundances up to 80.72 MP/ m3 detected in surface water samples and 1.76 MP/ g for sediment samples. Fibres and fragments were the most commonly observed morphologies in surface water and sediment samples; with fibres comprising up to 75.68 % in surface waters and 45.54 % in sediments, and fragments comprising up to 19.84 % in surface waters and 41.07 % in sediment samples. Polyethylene, polypropylene and polyester were the most dominant polymers observed in water and sediment samples, and both buoyant and non-buoyant polymers were observed of different morphologies for the study areas of Durban Bay and the Hennops River. Microplastic particles less than 1 mm in diameter were the most commonly observed size ranges relative to microplastic particles greater than 1 mm in diameter. Sites located nearby to river inflows and stormwater drains showed relatively higher microplastic abundances. A spatial analysis of the data showed the water bodies were subject to a wide array of anthropogenic activities which serve as inputs of microplastic pollution. The reporting of microplastic pollution in the selected aquatic systems substantiates real-time data which is required to implement policies to aid mitigating the risks associated with accumulating microplastic levels.
A dissertation submitted in fulfilment of the requirements for the degree of Master of Science to the Faculty of Science, School of Chemistry, University of the Witwatersrand, Johannesburg, 2023