Microplastics in South African Aquatic Environments: A Systematic Review of Spatial Distribution, Analytical Methods, and Research Trends (2012–2025)
摘要
Microplastic pollution has emerged as an important environmental concern in South Africa, yet research efforts remain spatially uneven and methodologically diverse. This systematic review synthesizes peer-reviewed studies published between 2012 and 2025 to evaluate the occurrence, spatial distribution, temporal trends, analytical approaches, and regulatory context of microplastics across South African environments. Studies conducted in marine, estuarine, freshwater, and wastewater systems were systematically examined. The spatial distribution of available studies reveals a pronounced coastal and urban bias, with most research concentrated in the Western Cape and KwaZulu-Natal provinces, while extensive inland regions remain comparatively underrepresented. Microplastics were reported in surface waters, sediments, wastewater effluents, and biological samples. In term of microplastic shape, fibres and fragments were dominant across environmental matrices. Polyethylene, polypropylene, and polyethylene terephthalate were the most frequently identified polymers. The majority of particles were inferred to be secondary microplastics generated through the fragmentation of larger plastic debris. Reported concentrations varied widely among studies, reflecting differences in sampling strategies, extraction procedures, analytical techniques, and reporting units. A total of 28 peer-reviewed studies published between 2012 and 2025 were included, comprising marine (43%), freshwater (36%), estuarine (14%), harbour (4%), and wastewater treatment plant (4%) investigations. Research output increased substantially after 2020, driven largely by expanding investigations in freshwater systems affected by urbanization and wastewater treatment processes. However, persistent inconsistencies in methodological approaches and quality assurance reporting continue to limit cross-study comparability. Despite growing evidence of widespread microplastic contamination, South Africa currently lacks dedicated regulatory frameworks addressing microplastics. This review identifies critical knowledge gaps and highlights the need for harmonised analytical methodologies and policy-relevant monitoring frameworks to support effective management and mitigation of microplastic pollution.