Avaliação da qualidade da água da Lagoa do Mocambinho, zona urbana de Teresina-PI

Abstract

This study aimed to evaluate the water quality of the Mocambinho Lagoon, loca-ted in Teresina-PI, considering the impact of untreated urban effluents. For ecotoxicolo-gical analysis, bioassays were conducted with Allium cepaL. (phytotoxicity test) and Ar-temia salina (acute toxicity test) to detect lethal effects. Sampling was carried out at two strategic points: Point 1 (upstream) and Point 2 (downstream), with visual differences in effluent load.The results of the bioassays with Allium cepa L. indicated statistically signi-ficant variations in the increase of bulb weight at Point 1, attributed to the greater avai-lability of organic nutrients. However, no significant differences were observed in root length and quantity between the sampled points, suggesting limited chronic toxicity at sublethal levels. For the Artemia salina assay, lethal concentration values were 0.96% for Point 1 (classified as highly toxic) and 1.96% for Point 2 (moderately toxic),indicating higher toxicity associated with areas of greater effluent discharge.It is concluded that the water quality of the Mocambinho Lagoon is compromised, with evidence of organic pollution and nutrient enrichment, favoring eutrophication and the proliferation of aquatic macrophytes. These findings highlight the need for the implementation of environmental management strategies, systematic water quality monitoring, and control of effluent dis-charge to mitigate the observed ecotoxicological impacts.