Impacto de contaminantes emergentes em estuários urbanizados: efeitos em organismos não-alvos e avaliação de risco ecológico

Abstract

Anthropic activities carried out on coastal regions result in the production and release of wastes, such as industrial, hospital and domestic effluents, which end up reaching the aquatic environment. Among the contaminants present in urban effluents, the so-called contaminants of emerging concern (CECs) have received great attention from the scientific community in recent years. CECs are substances from domestic, agricultural or industrial activities that have been found in multiple environmental compartments in trace concentrations. This group of substances includes pharmaceuticals and personal care products (PPCPs), hormones, disinfection products, antiseptics, some pesticides and biocides, flame retardants, stimulants (caffeine), among others. The present study aimed to evaluate the toxic effects of three CECs (the hormone ethinyl estradiol - EE2, the drug acetylsalicylic acid ASA and the bisphenol-A - BPA) on marine organisms and to quantify them, in addition to caffeine (CAF), in three estuaries from the metropolitan area of Fortaleza (RMF) to estimate the environmental risks associated to these substances. The toxicity of the studied CECs was measured by acute and chronic toxicity tests using marine invertebrates. LC50 values calculated in the acute toxicity tests with microcrustaceans showed that the compounds were more toxic to M. juniae than to Artemia sp. Among the three contaminants tested, EE2 was the most toxic (LC50-48h = 18.4 ± 2.7 mg.L-1 to Artemia sp.; LC50-96h = 0.36 ± 0.07 mg.L-1 to M. juniae). The three compounds significantly affected the embryonic development of the sea urchins at all concentrations tested, including the lowest and those of ecological relevance. The CECs, including also CAF, were quantified in water samples from the estuaries of the Ceará, Cocó and Pacoti rivers. The results indicated that the rivers analyzed presented CAF and BPA in the water column samples and that the concentrations of such compounds ranged between 231.1 – 427.1 µg.L-1 for CAF and from 71.6 – 188.9 µg.L-1 for BPA. Based on the environmental concentrations and the toxicity of these compounds to non-target organisms, ecological risk analysis was performed for the studied rivers, indicating that all of them are under high environmental risk, since the local biota is likely to suffer adverse effects due to CAF and BPA.