Influence of physicochemical and chemical parameters on polybrominated diphenyl ethers in selected landfill leachates, sediments and river sediments from Gauteng, South Africa

摘要

Polybrominated diphenyl ethers (PBDEs) are known to be persistent, endocrine disruptors and bioaccumulative and can cause adverse health effects in animals and humans. In this study, river and landfill sediment samples were collected from selected rivers and municipal solid waste landfill (MSWL) sites across Gauteng Province in South Africa to determine the levels of common PBDEs (BDE-17, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183 and BDE-209). The mean and median concentrations of Sigma(8) PBDEs from river sediment samples was 2.4 and 0.4 ng g(-1), respectively, and a range of 0.8-114 ng g(-1). The highest concentration of Sigma(8) PBDEs (43.6 ng g(-1)) was observed at Jukskei River with more than two orders of magnitude greater than the rest. The observed total PBDE concentrations in landfill sediment and leachate samples ranged from 0.8 to 8.4 ng g(-1) and 127-3,702 pg L-1 for the two matrices. BDE-209 was predominantly detected in most of the sediment samples. Two of the MSWLs which are lined with geomembranes gave the highest concentrations of Sigma(7) PBDEs (2,678 and 3,702 pg L-1). Correlation values for Sigma(7) PBDEs versus Co (r = 0.65), Cu (r = 0.52), Mn (r = 0.10), Mg (r = 0.76), Ca (r = 0.66) and Ni (r = 0.77) with a statistical significance (p < 0.05) were observed except for Na, Cr, Pb, K, Fe and Zn (p > 0.05). The observed positive correlation may suggest a possible influence of trace metals on PBDE concentrations in leachates. Furthermore, a test of relationship between major anions and PBDEs yielded positive relationship with Cl- (r = 0.94, p = 0.16), F- (r = 0.97, p = 0.21), Br- (r = 0.6, p = 0.29) and NO32- (r = 0.96, p = 0.08) with an insignificant statistical difference. However, evaluation of the relationship between some water quality parameters (pH, dissolved oxygen and electrical conductivity) gave negative correlation with PBDE concentrations.