Daphnias spp. as bioindicator organisms of toxicity and environmental characterization of eutrophized aquatic systems

Abstract

The ecotoxicological study is a tool for determining the harmful effects of chemical agents on the environment, enabling the verification of the ecotoxicological characteristics of chemical substances, mechanisms of action on living organisms, definition of guidelines for controlling the quality of effluents and evaluation of efficiency of water treatment processes. Therefore, this article presents a review on the assessment of ecotoxicity as an environmental characterization tool in eutrophicated aquatic systems using Daphnias spp. as bioindicator organisms. The studies evaluated showed that cyanotoxins cause inhibition of feeding activity, decreased growth, low reproduction rate, poor offspring formation, decreased lifespan and increased tolerance to toxins throughout generations of this microcrustacean. Acute toxicity analyzes showed different toxic effects, as the results depended on the strain tested. Some factors are attributed to the toxicity of cyanobacteria extracts in zooplanktonic organisms, mainly nutritional inadequacy, decreased filtration activity, inhibition of digestive enzymes, bioaccumulation and oxidative stress.