ECOTOXICOLOGY AS A TOOL TO MONITORING AQUATIC ECOSYSTEMS

Abstract

Aquatic Ecotoxicology is a science created to solve problems with water contamination by toxic compounds. The analytical framework employed is capable of predicting biological responses to the toxicity of chemical compounds through concentration-effect and concentration-response curves, and also enables evaluating the ecotoxicity of disturbed environments. Employing ecotoxicological assays in environmental evaluations is germane, as some factors are not assessed through abiotic variables, e.g. the bioavailability and interactions between pollutants effects. The aim of this review was to demonstrate the suitability of traditional ecotoxicological tests for biomonitoring freshwater ecosystems, while listing the pros and cons of this approach. This way, we described desirable characteristics of bioindicators that should be considered for the application in ecotoxicological bioassays and the best way of analyzing their responses from exposure to toxics. Moreover, the present review also discusses a recent method known as Real-Time Automated Biomonitoring Systems, which makes use of sentinel organisms in trying to detect behavior or physiological alterations derived from exposure to contaminants or pollutants. The method is effi cient, because the sentinel organisms enable detecting sublethal concentrations of the toxic agents, thus working as true ‘biosensors' of water quality. Although ecotoxicology evaluation is of prime importance in analysing the environmental health of aquatic ecosystems, Brazilian legislation cares little for the ecotoxicity of pollutant discharges. Only in some Brazilian States, like Santa Catarina and Parana, present specific official rules stating accepted toxicity factors to each kind of discharge.In summary, ecotoxicology provides efficient analytical tools that should be used following specific criteria according with the water quality and kind of contamination to be evaluated.