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Abstract

Bisphenols are a group of industrial chemicals increasingly recognized as contaminants of emerging concern because of their presence in the environment and endocrine disrupting effects. They are used in the production of polycarbonate plastic, epoxy resins and thermal paper, in most cases without restriction. The global exception is bisphenol A, which is banned in infant bottles and is, together with bisphenol S, authorized under European regulation with a specific migration limit for plastic food contact materials. Bisphenol A is the most abundant and well-studied of the group, whereas for other bisphenols available studies do not adequately reflect their occurrence, fate and potential toxicity. This absence of data is a combination of the lack of awareness of bisphenol A analogues and related toxicity and validated analytical methods.
In this work, reliable, sensitive and accurate gas and liquid chromatography MS-based analytical methods for target analysis of 18 bisphenols and suspect and non-target based analysis of their metabolites/transformation products were developed. These methods were applied to determine trace amounts of bisphenols in the aqueous environment, which, in this thesis, includes surface and drinking water, wastewater and aqueous-based food simulants. With developed methods, their stability, removal efficiency, reaction kinetics, and the identification of metabolites/transformation products during biological and photochemical processes were addressed. The migration of bisphenols from food contact materials, a source of bisphenols to humans and environment, was also investigated, and their toxicity towards algae and bacteria studied.
The results showed that bisphenols are stable for up to four weeks under experimental conditions allowing the development of sampling and analytical protocols with assured stability of tested compounds. All tested bisphenols were present in wastewaters at ng L-1 levels, their removal efficiency and kinetic depended on the type of treatment, and mostly followed pseudo-first-order kinetics. Biological, UV photolysis and advance oxidation processes yielded high removal efficiencies. However, a single treatment did not lead to complete mineralization, and transformation products were confirmed: three new bisphenol S metabolites, 11 novel phototransformation products of bisphenol F, S and Z and 11 newly identified bisphenol F and S biotransformation products. Bisphenols were also shown to leach from food contact materials into food simulants for different beverages (ng L-1 ̶ μg L-1), and it was also shown that the degree of leaching was dependent on migration conditions. Linings of beverage cans and reusable steel bottles were identified as the source of bisphenol A and bisphenol F isomers. Moreover, toxicity models of bisphenol A and F towards algae and bacteria revealed an underestimation of mixture toxicity towards experimental data.
In summary, the confirmed presence of bisphenols in the aqueous environment emphasizes the need for new treatment technologies or combinations of the existing ones. The thesis delivers new insights into the stability of bisphenols during analysis and their fate during water treatment, addressing not only the parent compounds but also their metabolites/transformation products. It also provides new knowledge about the migration of bisphenols from food contact materials, which represent a significant source of human exposure.