An integrated method for the simultaneous determination of alkylphenol ethoxylates and brominated flame retardants in sewage sludge samples by ultrasonic-assisted extraction, solid phase clean-up, and GC-MS analysis

Abstract

Generally, a major route of alkylphenol ethoxylates (APEs) and brominated flame retardants (BFRs) to enter the environment is via the wastewater treatment works (WWTW) facilities. Consequently, the levels of APEs and BFRs in sewage sludges may give an indication of the general use and exposure of these compounds. The present study was aimed at an integrated method for the analysis and quantification of APEs and BFRs in sewage sludge from selected wastewater treatment plants. The optimization of the extraction procedure included variation of the amount of extracted biomass, the duration, temperature during sonication as well as type of extraction solvent. Chromatographic determinations of APEs and BFRs were carried out with gas chromatography equipped with mass spectrometry detector after derivatization with heptafluorobutyric anhydride (HFBA). The mean percentage recoveries ranged from 39% to 79% (n=3) for sewage sludge after extracting 5g biomass sludge with hexane: acetone (4:1) at 55°C for 45min in two cycles. The mean concentrations of APEs obtained ranged from<LOQ to 365ngg−1, <LOQ to 166ngg−1, <LOQ to 642ngg−1 while the concentration of BFRs obtained range from<LOQ- 17ngg−1, <LOQ to 163ngg−1, <LOQ to 14ngg−1 for sludge samples from Leeuwkuil, Rietspruit, and Sebokeng, respectively. All compounds, except for nonylphenol (NP), BDE47, and BDE154, were detected from the Rietspruit WWTW. The presence of these pollutants in Rietspruit WWTW may be attributed by the fact that this treatment plants treat wastewater from domestic as well industrial discharges from the surrounding area.