Contaminação por metais e metaloides e sua destoxificação pela rota bioquímica da metalotioneína em raias Gymnura cf. micrura (Myliobatiformes: Gymnuridae) do Maranhão

Abstract

Metals and metalloids are noteworthy among aquatic pollutants as, in addition to their toxicity, they can bioaccumulate in marine ecosystems. Rays from the Gymnuridae family, being coastal animals and directly associated with the substrate, can present high metal and metalloid concentrations in their tissues. Furthermore, they are consumed in the state of Maranhão by vulnerable populations and sold freely, causing significant ecological and human risks. This dissertation aims to determine the concentrations of toxic and essential metals and metalloids by inductively coupled plasma spectrometry and of the metalloprotein metallothionein by UV-Visible spectrophotometry in stingrays of the species Gymnura cf. micrura collected in four areas of the state of Maranhão. All parameters were statistically correlated to evaluate the detoxification pathway of metallothionein and potential protective effects of essential elements against toxic elements. Calculations were also carried out to assess meat consumption risks of the studied species for the human population. No correlations between the determined elements with metallothionein in muscle were noted. The concentrations of As (5.250 ± 2.3872), MeHg (90% of total Hg - 0.55 ± 0.027), Mn (1.155 ± 0.454) and Pb (0.025 ± 0.0064) were above values allowed by various health inspection bodies, indicating risks regarding the contamination level in the consumption of this species. Furthermore, a risk for babies, children, young people, and adults, both female and male, in relation to As was observed. Therefore, the prohibition of the consumption of Gymnura cf. micrura is recommended, to avoid health problems for the human population and in view of this, use this as an indirect tool for conserving Maranhão's Biodiversity.