Abstract

MENDONGA, Jaísa Marília dos Santos; NAVONI, Julio Alejandro; MEDEIROS, Guilherme Fulgencio de  and  MINA, Isabel Maria Pinto. Toxicity tests for the evaluation of estuarine surface waters using Nitocra sp. as an alternative test organism. Acta toxicol. argent. [online]. 2022, vol.30, n.3, pp.5-5. ISSN 1851-3743.

Increasing pollution of marine and estuarine environments from wastewater discharge is a worldwide problem. Eco-toxicological tests are widely used to monitor the effects of this type of pollution and are currently being incorporated into the environmental legislation of several countries, including Brazil. However, few studies have been conducted in coastal areas, and standardization of methods with native organisms representative of local ecosystems is insufficient. Nitocra sp. has been efficiently used in ecotoxicological tests with sediments and interstitial waters, and its suitability for estuarine surface water analysis needs to be assessed. Point samples from the lower Jundiaí-Potengi estuary (JPE) in areas with (CE) and without (SE) discharge of treated effluents were collected monthly for 18 months. Nitocra sp. and Mysidopsis juniae (standardized species) were the test organisms used in the ecotoxicological assays. The lethal (mortality rate) and sublethal (reproduction rate) effects were analyzed considering the microbiological and physicochemical characterization of the tested samples. Dissolved oxygen, salinity, biochemical oxygen demand, ammoniacal and total ammoniacal nitrogen, total nitrogen, oils and greases, suspended and settleable solids, total potas-sium and thermotolerant coliform bacteria determined in samples from CE and SE, reflect varying levels of pollution at the sampled sites. The control charts of Nitoera sp. and M. juniae indicated good reproducibility in the laboratory, and although the test organisms had different ecotoxicological profiles, the mortality rate of both organisms was related to the discharge of treated wastewater. The use of different test organisms increases the representativeness of the ecotoxicological tests. Given the profile of Nitoera sp. in JPE monitoring, further studies, including the use of nauplii in bioassays, are needed to establish it as standardized test organism.

Keywords : Ecotoxicology; Copepods; Domestic effluents; Jundiaí Potengi Estuary.

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