Aerobic degradation of tetramethyl bisphenol F (TMBPF) with activated sludge: Kinetics and biotransformation products.

This study investigated the bio-degradation kinetics of tetramethyl bisphenol F (TMBPF), a non-estrogenic alternative to bisphenol A (BPA). Batch biotransformation experiments were performed whereby samples were inoculated with activated sludge and analysed using liquid chromatography-Orbitrap-tandem mass spectrometry (LC-Orbitrap-MS) utilising two non-targeted workflows (commercial and freely available online) for biotransformation products (BTP) identification. The degradation of TMBPF followed single first-order reaction kinetics and depended on the initial concentration (ci) with faster degradation -kt = 0.16, (half-life = 4.4 days) at lower concentrations ci = 0.1 mg L-1, compared with -kt = 0.02 (half-live = 36.4 days) at ci = 10.0 mg L-1. After 18 days, only 8% of the original TMBPF remained at the lowest tested concentration (0.1 mg L-1). Twelve BTPs were identified, three of which were workflow and one condition-specific. The highest relative quantities of BTPs were observed in nutrient-mineral and mineral media after ten days, while after 14 days, 36 and 31% of TMBPF (ci = 1 mg L-1) remained in the nutrient-mineral and mineral media, respectively. Also, the kinetics of TMBPF and its BTPs were the same with and without an additional carbon source. A newly proposed biodegradation pathway for TMBPF involves cleavage of the methylene bridge, hydroxylation with further oxidation, sulphation, nitrification, nitro reduction with further oxidation, acetylation, and glycine conjugation, providing a deeper insight into the fate of TMBPF during biological wastewater treatment.

Degradation and toxicity of bisphenol A and S during cold atmospheric pressure plasma treatment.

Bisphenols are widely recognised as toxic compounds that potentially threaten the environment and public health. Here we report the use of cold atmospheric pressure plasma (CAP) to remove bisphenol A (BPA) and bisphenol S (BPS) from aqueous systems. Additionally, methanol was added as a radical scavenger to simulate environmental conditions. After 480 s of plasma treatment, 15-25 % of BPA remained, compared to > 80 % of BPS, with BPA being removed faster (-kt = 3.4 ms-1, half-life = 210 s) than BPS (-kt = 0.15 ms-1, half-life 4700 s). The characterisation of plasma species showed that adding a radical scavenger affects the formation of reactive oxygen and nitrogen species, resulting in a lower amount of ˙OH, H2O2, and NO2- but a similar amount of NO3-. In addition, a non-target approach enabled the elucidation of 11 BPA and five BPS transformation products. From this data, transformation pathways were proposed for both compounds, indicating nitrification with further cleavage, demethylation, and carboxylation, and the coupling of smaller bisphenol intermediates. The toxicological characterisation of the in vitro HepG2 cell model has shown that the mixture of transformation products formed during CAP is less toxic than BPA and BPS, indicating that CAP is effective in safely degrading bisphenols.

Kinetics and biotransformation products of bisphenol F and S during aerobic degradation with activated sludge.

Bisphenol F (BPF) and bisphenol S (BPS) are becoming widespread in the environment despite the lack of information regarding their fate during wastewater treatment and in the environment. This study assessed the biodegradation kinetics of BPF and BPS during biological wastewater treatment with activated sludge using GC-MS/MS, and the identification of biotransformation products (BTPs) using LC-QTOF-MS. The results showed that BPF and BPS degrade readily and unlikely accumulate in biosolids or wastewater effluent (ci = 0.1 mg L-1, half-lives <4.3 days). The first-order kinetic model revealed that BPF (kt = 0.20-0.38) degraded faster than BPS (kt = 0.04-0.16) and that degradation rate decreases with an increasing initial concentration of BPS (half-lives 17.3 days). The absence of any additional organic carbon source significantly slowed down degradation, in particular, that of BPS (lag phase on day 18 instead of day 7). The machine-learning algorithm adopted as part of the non-targeted workflow identified three known BTPs and one novel BTP of BPF, and one known and ten new BTPs of BPS. The data from this study support possible new biodegradation pathways, namely sulphation, methylation, cleavage and the coupling of smaller bisphenol moieties.

The migration of bisphenols from beverage cans and reusable sports bottles.

A precise and accurate GC-MS/MS method with ng L-1 LLOQs, acceptable recovery (78-107%) and estimated uncertainty (U > 20%, except at LLOQ) was developed following the Eurachem guidelines. We established the migration and stability of twelve bisphenols in two food simulants (C: 20% ethanol, and B: 3% acetic acid) from beverage cans (n = 16) and reusable metal and plastic sports bottles (n = 51). Bisphenols were stable in dried (eight weeks, -20 °C) and derivatised extracts (seven days, 21 °C). Cans leached BPA (<5865 ng L-1), three BPF isomers (8.2-1286 ng L-1) and BPAP (1.6 ng L-1), while bottles leached BPA (<222 ng L-1) and BPF, BPE, BPB and BPZ (1.1-4.6 ng L-1). Simulant C was more aggressive than simulant B, and concentrations of bisphenols decreased with consecutive exposure to simulants. Levels of BPA migrating from cans did not exceed the specific migration limits.