Biomarcadores em populações de Kinosternon scorpioides (Linnaeus, 1766) (Testudines: Kinosternidae) como indicadores de impacto ambiental em uma área protegida na Amazônia maranhense, Sítio Ramsar Brasileiro

Abstract

Biomarkers are necessary in biomonitoring studies to detect biological responses based on the analysis of exposure levels of aquatic species to pollutants in their natural environment. The objective of the study was to analyze biochemical and mutagenic responses in Kinosternon scorpioides (Linnaeus, 1766) as indicators of environmental quality in an Environmental Protection Area located in the Eastern Amazon of Maranhão. We examined changes in the enzymes Glutathione S-Transferase (GST) and Catalase (CAT), as well as cytological analyzes of blood smears from K. scorpioides specimens collected in an urbanized (A1) and vegetated (A2) region in a protected area in the Maranhão Amazon, in addition to the scientific breeding site (A3). We found positive linear correlations between GST and CAT activities and biometrics. The GST concentration was higher in breeding individuals than in situ, with no statistical differences being observed between the enzyme activities of animals from areas A1 and A2. Unlike sex, environment and seasonal period simultaneously affected enzyme activities. Regarding mutagenic reactions, we recorded nuclear abnormalities such as micronuclei (n=91), binucleated erythrocytes (n=14), notched (n=81), lobulated (n=35), segmented (n=16) and displaced (n =253). Breeding animals did not present nuclear anomalies. The mean and standard deviation (1.13±0.47) of micronucleus were different from other species of chelonians from the natural environment. Displaced and binucleated nuclei had the highest frequency (51.63%) and lowest frequency (2.85%), respectively. The lobulated nucleus showed significant differences between environments (p=0.02839), while the segmented (p=0.02949) and displaced (p=0.0008336) showed significant differences in the dry and rainy periods. The amount of micronucleus found in K. scorpioides was not significant. Our study provided pioneering data on the biochemical and mutagenic responses of an Amazonian turtle species, demostrating that enzymatic responses and nuclear anomalies change depending on the type of environment and climatic season, indicating how maintaining protected areas is vital for turtle conservation freshwater in the Amazon.