Polybrominated diphenyl ethers (PBDEs) in sediment by salinity and land-use type from Australia

Brominated flame retardants, including polybrominated diphenyl ethers (PBDEs) have been incorporated in numerous products to reduce flammability. Depending on their bromination, PBDEs are relatively persistent in the environment and have the potential to bioaccumulate through the food web. The present study was initiated to provide a better understanding on the levels and possible origin of PBDEs in the aquatic environment of Australia. PBDEs were detected at 35 out of 46 sites and concentrations were relatively low in the majority of samples analysed. Mean+/-standard deviation and median SigmaPBDE concentrations across all sites were 4707+/-12,580 and 305 pg g(-1) dw, respectively, excluding the limit of detection. At 83% of sites, concentrations were below 1000 pg g(-1) dw, whereas elevated levels were found at sites downstream of STP outfalls and in areas dominated by industrial and urban land-use types. Concentrations of PBDEs differed significantly (p=0.007) among sites according to predominant type of land-use. Significantly (p=0.02) higher SigmaPBDE concentrations were also present in estuarine compared to freshwater environments, while PBDEs were below the limit of detection at the marine site. At most sites, BDE-209 contributed the highest proportion to the SigmaPBDE concentrations. The exception was one site with an elevated concentration of BDE-183. Sampling and analytical variability were investigated as part of this study. Results showed generally satisfactory results for repeat analysis at a different laboratory and low variability among samples collected within 1000 m at low contaminated sites. However, at sites with elevated PBDE levels, sampling variability was high, with several fold to magnitudes of higher concentrations present among replicate sites. Corresponding to findings from elsewhere, these results demonstrate that urban and industrial activities provide the key input sources of PBDEs to the aquatic environment and provide a baseline for further investigation into the specific origin of contamination, as well as information on the background status of aquatic sediment contamination with PBDEs.