Pesquisa e quantificação de metais em quatis (nasua nasua) e em gambás (didelphis sp.) de vida livre que coabitam diferentes parques urbanos de belo horizonte - minas gerais.

Abstract

Metals are divided into two classes: essential and non-essential or toxic, the latter of which can accumulate in the food chain and cause harm to organisms. Human activities are the main sources of release of various metals into the environment, whether toxic or essential. In this context, the state of Minas Gerais is considered the largest producer of minerals in Brazil, and the main mining site in the capital of Minas Gerais is Serra do Curral, an important conservation area in Belo Horizonte. The site is home to several species of wild animals, including coatis (Nasua nasua) and opossums (Didelphis sp.), which roam the region. The impact that metals can have on urban environments, especially on wild animals, is still unknown. The aim of this research was to identify and quantify, for the first time, the presence of toxic and essential metals in free-living coatis (Nasua nasua), white-eared opossums (Didelphis albiventris) and black-eared opossums (Didelphis aurita) that cohabit different urban parks in Belo Horizonte, Minas Gerais. For this purpose, free-living coatis and opossums were captured in six urban parks in Belo Horizonte, from 2022 to 2024, covering dry and rainy seasons. Blood and hair samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). A total of 160 coatis were captured, of which 148 hair samples and 61 blood samples were analyzed for toxicological analysis. Regarding opossums, 99 individuals were captured, of which 90 fur samples and 13 blood samples were analyzed for toxicological analysis. The results of the analyses from coati samples revealed that concentrations of copper, molybdenum, manganese and iron were higher in the blood of animals captured during the dry season, while in the fur, copper, zinc, molybdenum and selenium were higher in animals captured during the rainy season; and lead concentrations were higher in animals captured during the dry season. Adult coatis presented higher concentrations of manganese and nickel in the blood, and lead, selenium and molybdenum in the fur. Analyses between the sexes revealed higher concentrations of cadmium and mercury in the fur and blood of females, respectively, while males presented higher concentrations of selenium and copper in the fur and blood, respectively. Coatis with greater weight presented higher concentrations of lead, selenium, manganese and arsenic in the fur. Regarding opossums, the study showed that in the fur samples, mercury and molybdenum were higher in animals captured during the dry season. Age also influenced the concentrations of metals, with adults presenting higher values ​​of chromium, lead, manganese and molybdenum, while infants and juveniles presented higher concentrations of copper. Females presented higher concentrations of zinc in their fur and lead in their blood. Heavier opossums presented higher concentrations of arsenic in their blood and of lead and iron in their fur. Finally, the comparison between the capture sites demonstrated relationships between different concentrations of metals in coatis and opossums. In coatis, differences were identified in the levels of iron, selenium and manganese in the fur and selenium in the blood. In opossums, the variations included the metals chromium, arsenic, iron, zinc, uranium, lead, selenium and manganese in the fur and aluminum in the blood. These differences may be related to proximity to sources of industrial or mining pollution, as well as to different patterns of land use and species habits, which influence exposure to contaminated areas. The results obtained showed complex and specific patterns that associate the presence of metals with the environmental, biological and geographic conditions analyzed, showing that the species studied can be considered bioindicators of environmental quality due to their sensitivity to variations in contamination concentrations, without presenting clinical signs suggestive of intoxication by the elements. In addition, the quantification of metals in wildlife proved to be an effective tool for assessing the impacts of mining and industrial activities on urban ecosystems.