Legacy and novel brominated flame-retardants in different fish types from inland freshwaters of South Africa: levels, distribution and implications for human health.

This study report the presence of polybrominated biphenyls (PBBs), polybrominated diphenyl ethers (PBDEs) and novel brominated flame-retardants (NBFRs) in muscle tissues of Labeo capensis (mudfish), Labeo umbratus (moggel), Cyprinus carpio (carp) and Clarias gariepinus (catfish) from Vaal River, South Africa. The concentrations (in ng g-1 wet weight (ww)) of these contaminants ranged from LOQ to 12.8 ng g-1 ww in catfish, with lowest concentrations found for mudfish ranging from

Concentrations and human exposure assessment of per and polyfluoroalkyl substances in farmed marine shellfish in South Africa.

Although the consumption of seafood is a major route of human exposure to perfluoroalkyl substances (PFAS), data on their concentrations in marine shellfish and the exposure of the African population to PFAS through the consumption of shellfish is lacking. In this study, the concentrations of 15 PFAS were measured in four species of farmed marine shellfish by using a validated UHPLC-MS/MS method. These concentrations were used to determine the human daily intake of PFAS through the consumption of marine shellfish and the hazard quotient thereof. PFPeA, PFOS, PFHxA and PFTeDA were the most prevalent compounds with detection frequencies of 94, 88, 76 and 71%, respectively. The Σ11PFAS concentrations (in ng g-1 wet weight (ww)) ranged from 0.12 to 0.49, 4.83-6.43, 0.64-0.66 and 0.22 ng g-1 ww in abalone, mussel, oyster and lobster, respectively. The prevalence of PFCAs reflects the current contamination profile of PFAS in farmed shellfish. The estimated daily intake for Σ10 PFAS through the consumption of marine shellfish ranged from 0.05 to 1.58 ng kg-1 bw d-1. Overall, the hazard quotients for these compounds were low, indicating that these compounds do not pose a health risk to the South African population through shellfish consumption. This study provides background data for future studies on the occurrence of PFAS and other emerging contaminants in the African coastal environment.

Levels, distributions, and ecological risk assessments of polybrominated diphenyl ethers and alternative flame retardants in river sediments from Vaal River, South Africa.

Sediments are known to be the ultimate sink for most pollutants in the aquatic environment. In this study, the concentrations of both legacy polybrominated diphenyl ethers (PBDEs) and alternative halogenated flame retardants (AHFRs) were measured in sediments samples from the Vaal River catchment. The concentrations of Σ7BDE-congeners ranged from 20 to 78 ng g-1 dry weight (dw) with BDE-209, -99, and -153 as the dominant congeners. The concentrations observed ranged from 9.4-56, 4-32, and 1-10.6 ng g-1 for BDE-209, -99, and -153, respectively. The concentrations of AHFRs, mainly contributed by decabromodiphenyl ethane (DBDPE) at approximately 95% of total AHFRs, ranged from 64 to 359 ng g-1 dw while the concentration of polybrominated biphenyls (PBBs), mainly PBB-209, ranged from 3.3-7.1 ng g-1 dw. The ratios of AHFRs to PBDEs observed in this study were 0.76, 1.17, and 7.3 for 2-ethyl-1-hexyl-2,3,4,5-tetrabromobenzoate and bis-(2-ethylhexyl)-tetrabromophthalate (EH-TBB & BEH-TEBP)/penta-BDE; 1,2-bis-(2,4,6-tribromophenoxy) ethane (BTBPE)/octa-BDE; and DBDPE/BDE209, respectively. These results indicate dominance of some AHFRs compared to PBDEs. Our results indicates that BDE-99 poses high risk (RQ > 1) while BDE-209 posed medium risk (0.1 < RQ < 1). Though the concentration of DBDPE was several orders of magnitude higher than BDE209, its ecological risk was found to be negligible (RQ < 0.01). Thus, more attention is required to regulate the input (especially the e-waste recycling sites) of brominated flame retardants into the environment.

Development and validation of a confirmatory method for the determination of stilbene estrogens in ostrich serum.

A simple and accurate ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the first time as a confirmatory method for the simultaneous determination of stilbenes - hexestrol and diethylstibestrol in serum. Extraction was based on a simple acid denaturation of protein followed by liquid-liquid extraction using methyl tert butyl ether. Extracts were directly injected into the UHPLC-MS/MS without further purification. Excellent recoveries in the range 82-99% and 91-128% were obtained for hexestrol and diethylstibestrol, respectively. Both within-day repeatability and between-day reproducibility were generally satisfactory with RSD <20%. The linearity of the internal standard based matrix-matched calibration curve measured as the coefficient of regression (r2) was generally >0.99 for both hexestrol and diethylstibestrol. Both matrix effect and uncertainties associated with sample preparation and instrumental analysis were significantly reduced with the use of a deuterated compound (hexestrol-d4) as internal standard. The LOD and LOQ were 0.09 and 0.08 ng/ml, and 0.28 and 0.25 ng/ml, respectively, for hexestrol and diethylstibestrol. The method was found to be suitable for the simultaneous determination of hexestrol and diethylstibestrol in serum.

Optimization and Simultaneous Determination of Alkyl Phenol Ethoxylates and Brominated Flame Retardants in Water after SPE and Heptafluorobutyric Anhydride Derivatization followed by GC/MS.

A gas chromatography-mass spectrometry (GC-MS) method was investigated for the simultaneous analysis of two types of endocrine disrupting compounds (EDCs), i.e., alkylphenol ethoxylates and brominated flame retardants (BFRs), by extraction and derivatization followed by GC-MS. Different solid phase extraction (SPE) cartridges (Cleanert PestiCarb, C18, Cleanert-SAX and Florosil), solvents (toluene, tetrahydrofuran, acetone, acetonitrile and ethyl acetate) and bases (NaHCO3, triethylamine and pyridine) were tested and the best chromatographic analysis was achieved by extraction with Strata-X (33 µm, Reverse Phase) cartridge and derivatization with heptafluorobutyric anhydride at 55 °C under Na2CO3 base in hexane. It was observed that APE together with lower substituted PBBs (PBB1, PBB10, PBB18 and PBB49), HBCD and TBBPA can be determined simultaneously under the same GC conditions. This simple and reliable analytical method was applied to determining trace amounts of these compounds from wastewater treatment plant samples. The recoveries of the target compounds from simulated water were above 60 %. The limit of detection ranged from 0.01 to 0.15 µg L-1 and the limit of quantification ranged from 0.05 to 0.66 µg L-1. There were no appreciable differences between filtered and unfiltered wastewater samples from Leeuwkil treatment plant although concentration of target analytes in filtered influent was slightly lower than the concentration of target analytes in unfiltered influent water. The concentrations of the target compounds from the wastewater treatment were determined from LOQ upwards.