Biochemical biomarker profiles of different organs of Phrynops geoffroanus freshwater turtle (Testudines, Chelidae) reveal pollutant effects from an anthropized aquatic environment

Aquatic organisms are often exposed to various chemicals, whose individual components are likely to produce different responses within the organisms and/or interact leading to toxic effects. The Phrynops geoffroanus species ("Geoffroy's side-necked turtle", Schweigger, 1812), a freshwater turtle endemic of South America, is commonly found in polluted rivers that cross the urban area and receive domestic and industrial wastewater effluents. In order to evaluate changes in biochemical biomarker profiles in different organs (liver, heart, lung, pancreas, small and large intestines) of P. geoffroanus from an anthropized aquatic environment, we analyzed the responses of enzymes involved in xenobiotic biotransformation, antioxidant enzymes, and lipid peroxidation levels. Acetylcholinesterase (AChE) activity was also assessed to check for neurotoxic effects. Results revealed that the poor water quality of a highly anthropized stream perturbed the biochemical parameters of free-living freshwater turtles. Compared to animals from the reference site (breeding farm), those from the polluted site presented increased biotransformation activity, antioxidant responses, and lipid peroxidation levels, indicative of oxidative stress. AChE activity was decreased in the pancreas. Alterations of different biomarkers in specific organs indicated differences in susceptibility among different organs of this species. These data contribute to a better understanding of how these animals respond to environmental pollutants, suggesting this species as good sentinel organisms for ecotoxicological studies.