A newly published environmental study has found traces of pharmaceuticals, agricultural chemicals and metals throughout False Bay, raising concerns about the long-term accumulation of pollutants in one of the Western Cape’s most important coastal ecosystems.
The research, conducted by scientists from two Cape Town universities and published in the Marine Pollution Bulletin, identified a range of contaminants linked to human activity, including wastewater discharge, urban expansion and harbour operations.
Although researchers stressed that current contamination levels remain below internationally recognised ecological risk thresholds, they warned that the long-term presence of these substances requires continued monitoring.
Seabed Sediments Emerging As Pollution Storage Sites
One of the study’s most significant findings is that pollutant concentrations are considerably higher in seabed sediments than in surrounding seawater.
According to the researchers, this suggests that the ocean floor is acting as a long-term sink where contaminants accumulate over time rather than dispersing quickly.
Professor Leslie Petrik, head of the Environmental and Nano Science Group in the Department of Chemistry at the University of the Western Cape, said many of the pollutants detected originated from everyday products used by households and the agricultural sector.
Scientists found residues of pharmaceuticals and pesticides commonly used on land, indicating that these substances are entering marine environments through wastewater systems, runoff and coastal activities.
The accumulation of pollutants within sediments is particularly important because sediments can gradually release contaminants back into the marine environment, potentially exposing marine organisms over extended periods.
Researchers Call For Continued Monitoring
Environmental experts caution that pollutants stored in seabed sediments may eventually move through the marine food chain, affecting fish, shellfish and other marine species.
While the current study found no evidence of immediate ecological harm, researchers say understanding long-term exposure risks remains essential.
The findings come as coastal cities around the world face growing challenges linked to wastewater management, urbanisation and industrial activity, all of which can introduce contaminants into marine ecosystems.
Cape Town Deputy Mayor and Mayoral Committee Member for Spatial Planning and Environment Eddie Andrews noted that the report found contamination levels remained below thresholds typically associated with ecological damage.
According to Andrews, researchers did not identify adverse ecological effects linked to the pollutants at the concentrations currently recorded.
Nevertheless, scientists involved in the project believe regular environmental assessments are necessary to track future changes and identify emerging risks before they become more serious.
The study highlights the importance of ongoing marine conservation efforts and improved understanding of how pollutants move from urban environments into coastal ecosystems.
As environmental pressures continue to increase globally, researchers argue that long-term monitoring will be critical in protecting the ecological health of False Bay and ensuring informed management decisions in the years ahead.
Source: Marine Pollution Bulletin / University of the Western Cape