Avaliação ecotoxicológica da água por contaminantes metálicos em Danio rerio na bacia hidrográfica do rio Pedreira, Amapá: uma abordagem no ensino de química

Abstract

Water contamination in Amapá, particularly by heavy metals and organic pollutants from agriculture and lack of sanitation, threatens environmental health and traditional populations. The Pedreira River, vital for local communities, becomes the focus of study to assess these risks. To evaluate the occurrence of pollutants in the Pedreira River basin and study their toxicological impacts on the biological model Danio rerio (zebrafish) at different stages of development, proposing a didactic approach for chemistry teaching. Water and sediment samples were collected at seven points along the river. Physico-chemical analyses and toxicity bioassays were performed with adult and embryo zebrafish, following OECD 236 protocols and CONAMA standards. Genotoxicity parameters (micronuclei) and morphological alterations were evaluated. Physico-chemical analyses revealed acidic pH (4.71) and low dissolved oxygen levels, outside CONAMA Class 2 standards. Bioassays indicated significant frequencies of genotoxic damage, such as micronuclei (up to 18.9%) and blebbed nuclei, as well as vacuolated cytoplasm at critical points (P5 with 33.33%), suggesting a risk to cell survival and persistent environmental pressure.