The assessment of organic pollutant exposure and effects along the KwaZulu-Natal coastline

Abstract

Marine pollution monitoring has been active in South Africa for the past 40 years, but with large periods of neglect where no research has been done. South Africa is ideally situated along the primary global shipping route, making its harbours, especially along the east coast, some of the largest and busiest ports in the world (Marshall et al. 2003). Several recent studies have been focussing on metal pollutants in Richards Bay Harbour (Greenfield et al. 2011, 2014; Degger et al. 2011b) and one study on the persistent organic pollutants polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in Richards Bay Harbour (Degger et al. 2011a). The aim of this study was to successfully implement passive and active bio-monitoring methods using semi-permeable membrane devices (SPMDs) and indicator organisms (mussels) for chemical and biochemical analyses in Durban Harbour and Richards Bay Harbour. Biomarker analyses were done to determine physiological effects to organic pollutant exposures and organochlorine pesticides (OCPs), PCBs and PAHs were analysed using QuEChERS extraction and GC-GC-TOFMS for chemical analyses of both SPMDs and mussel tissue. Significance was taken at p < 0.05. The results showed low levels of OCPs exposure in mussels, while the SPMDs were able to detect slightly higher levels in Durban Harbour. Both mussels and SPMDs were able to successfully accumulate PCBs and PAHs at all sites. Both harbours had higher levels of these pollutants than at Sheffield Beach, and Richards Bay Harbour had higher levels of PAHs during the dry season survey due to an oil spill a few weeks earlier. The bio-markers were able to confirm oxidative stress and exposure effects due to organic pollutant exposure, which were confirmed by chemical analyses. The bio-markers were also able to confirm oxidative stress due to other environmental factors (freshwater runoff from high rainfall, tidal influences, food scarcity) at Sheffield Beach, which are not associated with organic pollutant exposure. The data collected from this study will contribute to baseline data on the state of Durban- and Richards Bay Harbours concerning persistent organic pollutants, and therefore open the door to further marine pollution monitoring studies along the east coast of South Africa.