OCCURRENCE OF POLYBROMINATED DIPHENYL ETHERS (PBDEs) IN SURFACE SEDIMENTS OF AN URBAN ARTIFICIAL LAKE IN BRAZIL

Abstract

Polybrominated diphenyl ethers (PBDEs) are persistent flame retardants widely used in everyday materials, with the potential to leach out and contaminate indoors and receiving waters. Despite their well-documented ecological risks, there has been limited reporting on PBDE levels in sediments from Brazilian freshwaters, motivating the monitoring of sediments from Paranoá Lake, in the Brazilian capital. After sampling, extraction, and analysis of congeners BDE-28, -47, -66, -85, -99, -100, -138, -153, and -154 by gas chromatography with electron capture detection, Σ9PBDE levels ranged from 3.9 ± 0.2 to 19 ± 1 ng g-1 dw, with higher concentrations attributed to effluent discharge from wastewater treatment plants (WWTPs), followed by the influence of storm drainage water contamination. The distribution of PBDE congeners suggested a predominant influence of the commercial pentaBDE formulation, likely DE-71. However, in points influenced by WWTPs, the prevalence of BDE-66 suggests biotic reductive debromination of high-brominated PBDE, possibly BDE-209, indicating the possible influence of the decabrominated formulation. The distribution of PBDEs in the environment, estimated using the EQC (equilibrium criterion) model, level I, indicated low concentrations in the water column, but also noteworthy levels in biota and sediment precursor materials. Finally, preliminary ecological risk assessment indicated the need for future further surveys.