Avaliação da degradação e dos níveis genotóxicos e citotóxicos de uma solução aquosa contendo Bisfenol A tratada pelo processo UV-solar/H2O2

Abstract

Bisphenol A (BPA) is a plasticizer widely used by industries in the manufacture of polycarbonate plastics and epoxy resins, as a result of which it has been detected in the environment in air, water, soil and sediments. BPA has received great attention from the scientific community, mainly due to the adverse effects that its exposure can cause to human health and living organisms, since it is a known endocrine disrupting chemical. Due to the occurrence in surface waters and its adverse effects, there is a need to develop treatment techniques that enable the effective degradation of BPA in water. In this context, this research investigated the degradation and mineralization of BPA by the UV-solar/H2O2 process on a laboratory scale. Initially, preliminary tests were performed varying the irradiation source, BPA/H2O2 ratio, temperature, initial H2O2 concentration, initial solution pH, and initial BPA concentration. The UVsolar/H2O2 process stood out for its efficiency and for its eco-friendly approach, since solar energy was used as an irradiation source. Through a response surface methodology, the experimental conditions of UV-solar/H2O2 were optimized, obtaining the following responses: pH 3.0, [BPA]0 = 25 mg L−1 , [H2O2] = 350 mg L−1 , T = 50 °C, reaching BPA degradation and mineralization of 77.4% and 38.2%, respectively, and a H2O2 consumption of 230 mg L−1 . From this optimized condition, different pH ranges (3.0; 5.0; 7.0; 9.0; and 11.0) were tested, resulting in better rates of BPA degradation (89.2%) and mineralization (49.0%) at pH 5.0. For greater reliability of the results, the identification of intermediate by-products of the reaction, performed by Gas Chromatography–Mass Spectrometry (GC–MS) analyzes, and the evaluation of genotoxicity and cytotoxicity were used to compare the solutions at pH 3.0 and 5.0. The solution at pH 5.0 showed a lower amount of identified by-products. In the genotoxicity tests with zebrafish (Danio rerio) and in the cytotoxicity tests with Allium cepa, it was possible to evaluate the cellular damage caused by the samples. For both tests, the BPA samples treated by the UV-solar/H2O2 were less toxic than the BPA raw sample and the solutions pH 5.0 provided lower levels of bio-toxicity when compared to the solutions pH 3.0. Therefore, the UV-solar/H2O2 process is efficient in the degradation and mineralization of BPA, in addition to reducing biotoxicity levels, being an efficient and eco-friendly alternative for the BPA degradation in aqueous solutions.