A peer-reviewed study published in the journal Marine Pollution Bulletin has identified South Africa’s coastline as among the most severely plastic-polluted in the southern hemisphere, with both the Atlantic and Indian Ocean shores recording plastic debris densities that exceed global average levels by a factor of more than three in the worst-affected zones.
The research, conducted by scientists from the South African Institute for Aquatic Biodiversity and the Oceanography Department at the University of Cape Town, identified river systems as the primary conduit for plastic pollution entering coastal waters. The study found that rivers flowing through major urban centres — particularly the Umgeni in KwaZulu-Natal and several smaller rivers in the Cape Flats — transport hundreds of tonnes of plastic waste into the sea annually, driven by inadequate municipal waste collection in informal settlement areas.
Marine biodiversity impacts identified in the research include entanglement of endangered species including the African penguin, Cape gannet and several shark species in discarded netting and packaging materials. Microplastic concentrations in the Benguela Current — one of the world’s most productive ocean upwelling systems that sustains South Africa’s fishing industry — were found to be higher than in comparable ocean systems globally, raising concerns about long-term ecosystem health.
The City of Cape Town and the eThekwini Municipality have both introduced plastic reduction policies in recent years, including levies on single-use plastics, extended producer responsibility programmes, and river mouth net-trap installations. Scientists say these measures are helping at the margins but that the root cause — inadequate waste infrastructure in high-density areas — requires urgent capital investment and sustained behaviour change intervention.
Environmental justice advocates have highlighted that communities nearest to polluted rivers and coastlines are predominantly low-income, reinforcing the intersection between environmental degradation and socioeconomic inequality in South Africa.
