Polybrominated diphenyl ethers (PBDEs) and hexabromobiphenyl in sediments of the Diep and Kuils Rivers in South Africa

This study reports the concentrations of polybrominated diphenyl ethers and hexabromobiphenyl in bottom sediment of two rivers within the city of Cape Town. Following the isolation of the target compounds by mechanical shaking technique, the routine analyses and structural elucidation of the target analytes were performed with high capillary gas chromatography with electron capture detection (GC-µECD) and gas chromatography-time-of-flight-mass spectrometry (GC-TOF-MS) techniques, respectively. The mean concentrations of the total PBDE varied in the range of 0.06 – 2.47 ng/g in the Diep River. These values were relatively higher in the Kuils River. The mean concentrations of BB 153 ranged from not detected (ND) –0.39 ng/g. Similarly, the mean concentrations of BB 153 in the Kuils River were in the range of ND –1.21 ng/g. The statistical analyses performed on these data showed that majority of the PBDE congeners, except BDE 209 had strong positive correlation with the total organic carbon (TOC). Although effluent discharges from nearby wastewater treatment plants were identified as important source of PBDEs, other notable sources, including grey water intrusion could contribute to the contamination of the upstream of both rivers.