RESUMO
The behavior of organic UV filters in aquatic ecosystems and living organisms raises concern. For the first time, biochemical biomarkers were evaluated in the liver and brain of juvenile Oreochromis niloticus exposed to 0.001 and 0.5 mg L-1 of a benzophenone-3 (BP-3), octyl methoxycinnamate (EHMC), and octocrylene (OC) mixture for 29 days. Before the exposure, the stability of these UV filters was investigated using liquid chromatography. The experiment with aeration in the aquarium showed a high percentage of concentration reduction (%) after 24 h: 62 ± 2 for BP-3, 96 ± 6 for EHMC, and 88 ± 2 for OC versus 5 ± 4 for BP-3, 8 ± 7 for EHMC, and 2 ± 3 for OC when without aeration. These results defined the bioassay protocol. The stability of the filters concentrations after being stored in PET flasks and subjected to freezing and thawing cycles was also verified. In PET bottles, the BP-3, EHMC, and OC presented concentration reductions of 8 ± 1, 28 ± 7 and 25 ± 5 respectively, after 96 h storage and four freezing cycles. In falcon tubes the concentration reductions observed were 47 ± 2 for BP-3, >95 ± 1 for EHMC and 86 ± 2 for OC after 48 h and two cycles. The 29 days of sub-chronic exposure indicated the occurrence of oxidative stress through the enhanced lipid peroxidation (LPO) levels for the groups exposed to both bioassay concentrations. The catalase (CAT), glutathione-S-transferase (GST), and acetylcholinesterase (AChE) activities did not show significant alterations. The genetic adverse effects were analyzed in erythrocytes of fish exposed to 0.001 mg L-1 of the mixture by comet and micronucleus biomarkers and no significant damage was observed.
