TOXICIDADE INDUZIDA PELA EXPOSIÇÃO DE Oreochromis niloticus AO EFLUENTE DE CURTUME: EFEITOS COMPORTAMENTAIS, BIOMÉTRICOS E MUTAGÊNICOS

Abstract

The environment is constantly impacted by human actions. The rapid development of the means of production and the lack of environmental awareness have led to the degradation of natural resources. One of the most impaired natural resources today is water resources. Pollution is the main cause of damage to aquatic ecosystems, with industrial effluents being the main source of contaminants. In this scenario, the tanning industries stand out, since the production of leather generates a highly toxic effluent due to its organic and non-organic components, such as heavy metals. In this way, the tanning effluent can cause environmental damage and impair the health and survival of exposed organisms. Thus, the objective of this study was to evaluate the effects of exposure to different concentrations of wet blue effluent on biometric parameters (growth, weight gain and Hepatosomatic Index - IHS), behavioral (feeding, movement, aggressiveness and response to the object strange) and mutagenic from Nile tilapia (Oreochromis niloticus). Two experiments were carried out: in experiment 1, fish were exposed to concentrations of 2.5% (0.005%) and 25% (0.05%) of the estimated environmental concentration (0.2%). In this study, Nile tilapia was exposed for a period of 96 hours and the effect of exposure to tannery effluent on biometric and behavioral parameters was evaluated. In the experiment 2, Nile tilapia was exposed to concentrations of 50% (0.1%) and 100% (0.2%) of the estimated environmental concentration of the tanning effluent for 96 hours and the biometric effects, behavioral and mutagenic. In the experiment 1 the tanning effluent caused an increase in IHS and aggressiveness in the fish exposed to the pollutant, without altering the other parameters evaluated. In the experiment 2 the tannery effluent married alteration in the foreign object response and increased frequencies of nuclear and micronuclei abnormalities in exposed fish. It was concluded that tannery effluent, even at concentrations below the estimated environmental concentration, presents toxicity to Nile tilapia and causes biometric, behavioral and mutagenic damages, which may imply ecological damages in fish survival and reproduction.