Characterization of polychlorinated biphenyl residues in the North End lake and Port Elizabeth harbour, South Africa

Persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs) are widespread in aquatic systems, they can bioaccumulate in the tissues of aquatic organisms, especially fish as they occupy a position near the top of the aquatic food web. PCBs are among the most toxic substances and have been shown to cause many adverse effects to humans and wildlife. High health risks are associated with populations that follow a diet high in fat content such as fish and shellfish in which PCBs bioaccumulate. Given the importance of industries and the potential health concerns of exposure to PCBs, the lack of information on environmental levels of PCBs in South Africa (SA) is significant and concerning. Less attention has been directed to analysis of PCBs in the South African environments due to high cost and lack of appropriate equipment. This study was the first conducted in order to assess the levels of PCBs in the environment of Nelson Mandela Bay Municipality (Port Elizabeth). The research was directed at determining the PCB levels in water, sediments, fish and mussels collected in the Nelson Mandela Bay Municipality. The sampling sites, North End Lake (NEL) and Port Elizabeth Harbour (PEH) were selected based on their location and the importance of activities taking place in these areas. In total 456 samples of water (dissolved and particulate phases), sediments, mussels and tissues of fish were analysed. Suitable analytical methods were based on the equipment and materials available at the Nelson Mandela Metropolitan University. Gas chromatography-mass spectrometry (GC/MS) was used to quantify PCBs in the samples using the internal standard method. Six indicator congeners (PCB nos. 28, 52, 101, 138, 153, 180) were chosen because they are mainly present in most PCB mixtures in environmental samples and they are recommended for regular monitoring. These congeners represent about 50% of the total non-dioxin like (NDL) PCBs in food. All these congeners were detected in the samples analysed. The total PCB concentrations in the sediments from the NEL and PEH ranged from 1.60 to 3.06 and from 0.56 to 2.35 ng g-1 dry weight, respectively. The concentrations of total PCBs in Mytilus galloprovincialis ranged from 14.48 to 21.37 ng g-1 wet weight and from 20.84 to 31.34 ng g-1 wet weight in Perna perna. Total PCBs in water ranged from 0.18 to 0.355 ng L-1. The concentrations of total PCBs in the liver, gonads, gills and muscle were 95.69, 57.49, 44.63, 34.14 ng g-1 lipid weight in Cyprinus carpio and 119.73, 59.21, 49.78, 34.63 ng g-1 in Oreochromis mossambicus, respectively. Fish liver was the most contaminated organ due to its high lipid content compared to other parts of fish analysed. The NEL was found to be more contaminated than the PEH. The main potential sources of PCB pollutants in both areas of this study are industrial and municipal discharges. The NEL is surrounded by many industries and serves as a potential pollutant sink due to wastewater and inflow entering into this lake. Four 0.227 kg meals of the edible part of fish (muscle) per month were recommended based on the non-cancer health endpoint and one 0.227 kg meal per month was recommended based on the cancer health endpoint. This research contributed to notify the public and relevant governmental departments on the PCB pollution status of sediments, water and aquatic life in the PEH and NEL