Ozonização aplicada ao tratamento de diclofenaco e avaliação toxicológica utilizando bioensaios vegetais.

Abstract

Despite having represented an improvement in the quality of life and longevity of the population, the increase in the consumption and production of drugs has led to the presence of these compounds in various environmental matrices. The incorrect disposal of medications and their low metabolism, in addition to the inefficiency of conventional treatments for their removal, contribute for these compounds to assume a pseudo-persistence behavior in the environment. Treated as a priority substance in European Union monitoring actions, diclofenac has proven toxicity to terrestrial and aquatic species. Therefore, its treatment represents the protection of ecosystem and human health. Ozonation is the best studied and often adopted treatment process for the treatment of drugs. However, avoiding the generation of secondary pollution through compounds formed after treatment is as important as removing the pollution generated by drugs. It is also of great relevance to monitor the effectiveness of treatments through toxicity tests.Plant bioassays are good alternatives for assessing the in vivo effects of toxic agents. Allium cepa is one of the species best used in genotoxicity tests. In this study, the removal of diclofenac through ozonation was evaluated, taking into account the phytotoxic, genotoxic, cytotoxic and mutagenic effects produced by this compound before and after being subjected to treatment, in order to monitor the real effect of this compound in non-target organisms: Allium cepa and Lactuca sativa. A synthetic effluent containing diclofenac at 25mg/L was produced and subjected to the treatment of different doses of Ozone: 0, 29.4, 58.9, 88.2, 176.4 and 352.8 mg O3/L. The diclofenac removal efficiency reached 91.68%. However, given that the dose used in this study was much higher than environmentally relevant doses, the removal of said compound was considered successful. The mitotic index and the cytokinesis index of the products generated during ozonolysis seem to be related to the removal of diclofenac and the possible products formed during ozonolysis. The use of these parameters in similar works represents an alternative for monitoring the environmental pollution generated by emerging contaminants before and after being submitted to treatment systems, such as diclofenac. Ozonation led to a reduction in effluent toxicity in Allium cepa considering the presence of micronuclei and chromosomal alterations, although the frequencies of (AC%) and (MUT%) were very low. No phytotoxic effects were observed on Allium cepa and Lactuca sativa. The treatment with ozonation applied to the drug in question represented ecosystem and human protection.