Análise de elementos traço em tartarugas marinhas da espécie Chelonia mydas encalhadas no Parque Nacional dos Lençóis Maranhenses

Abstract

Sea turtles found in Brazil face a high risk of extinction due to incidental fishing and marine pollution. They are classified on the Red List of the International Union for Conservation of Nature (IUCN) and on the National List of Endangered Species of Brazilian Fauna, of the Ministry of the Environment, in the categories “Vulnerable”, “Endangered” and “Critically Endangered”. Contamination by metals, for example, can cause significant effects on these species, compromising the balance of the ecosystems where they occur. In this context, stranded turtles can provide tissues for bioaccumulated metallic elements analysis, becoming important bioindicators of marine contamination. This study aimed to identify the concentrations of metals present in green turtles (Chelonia mydas) stranded in Lençóis Maranhenses, MA. Liver and muscle tissue samples were collected from individuals stranded on beaches between May and November 2016. The samples underwent drying and pulverizing processes at the Ecotoxicology Laboratory of UFMA, and were subsequently sent to the Environmental Sciences Laboratory of the Center for Biosciences and Biotechnology of UENF, RJ, and subjected to wet microwave digestion and analyzed by inductively coupled plasma optical emission spectrometry to quantify the elements Al, As, Cd, Cr n, Pb, Ni, Ba, Fe, Cu, Se, Zn, and Mn. The results indicated high levels of metals in the liver, evidencing a recent bioaccumulation process. The comparison of accumulated levels in C. mydas from other localities indicated that specimens stranded in Lençóis Maranhenses have elevated levels of Al in muscle and Cd in the liver. Furthermore, a positive correlation was observed between the concentration of Pb in the tissues (muscle and liver) and the biometric data. A protective effect of essential elements against non-essential ones in muscle (Fe:Al, Zn:Cd, and Cu:Pb) is suggested. These results highlight the importance of monitoring marine contamination through bioindicators and their implications for the conservation of endangered species.