Ecotoxicidade de acetona e etanol antes e após fotólise UVC e processo UVC/H2O2

Abstract

Some advanced oxidative degradation studies use organic solvents to solubilize poorly soluble compounds in aqueous media, without assessing possible toxic effects of by-products of these. The use of organic solvents for this purpose is a widely used method, but without analyzing the possible interferences of the same. This work evaluated the toxicity of solutions with acetone and ethanol 0.2% (v/v), before and after photolysis and UVC/H2O2 processes. Degradation tests were conducted in a 600 mL capacity bench reactor, using as a radiation source a high pressure mercury vapor lamp of 125W, depleted of its original bulb and immersed in the solution protected by a quartz bulb. Aliquots of the sample were taken, in times of up to 8 h of exposure. In the UVC/H2O2 process 100 mg L-1 of H2O2 was used, with reinjection when necessary. Acute toxicity was evaluated with seeds of Lactuca sativa (lettuce seeds), Daphnia magna and Aedes aegypti larvae. In the Lactuca sativa assays growth inhibition was observed for most of the degradation times tested, with both solvents. Similar results were also observed in the Daphnia magna tests. In the Aedes aegypti tests, for both processes, before and after treatment, no immobile individuals were observed. It was possible to observe that both solvents have toxicity during the treatment, but the acetone showed less interference when compared to the ethanol.