Environmental contaminant accumulation in freshwater turtles inhabiting three rivers of the permian Basin, New Mexico, USA

Abstract

Freshwater turtles are valuable sentinels of aquatic systems due to their long lifespans and resilience in environments impacted by contaminants. The Permian Basin, dominated by the oil and gas sector, spans western Texas and southeastern New Mexico, USA, including the Pecos River and its tributaries, the Delaware and Black Rivers. Our study assessed concentrations of eight environmental contaminants listed under the United States Environmental Protection Agency's Resource Conservation and Recovery Act of 1976 in the tissues of three turtle species from the rivers of the Permian Basin: the claws of the Texas spiny softshell (Apalone spinifera emoryi), and the claws and blood of the red-eared slider (Trachemys scripta elegans) and Rio Grande cooter (Pseudemys gorzugi). The Delaware River exhibited the highest levels of arsenic (As), mercury (Hg), selenium (Se), and chromium (Cr) in both claw and blood samples, potentially reflecting the industrial impact of oil and gas activities in the region. Contaminant concentrations reflected the trophic levels of different species, with carnivorous A. spinifera emoryi showing elevated levels of Se and Hg, and herbivorous P. gorzugi showing elevated levels of As and Ba. Linear regression analysis revealed a significant positive correlation between blood and claw contaminant concentrations for As, Ba, Se, and Pb. This study highlights turtles as effective sentinels, providing baseline data on contaminant concentrations in turtle tissue, identifying areas with elevated pollutants, and demonstrating their potential to track temporal trends in pollutant accumulation to inform resource management and pollution mitigation strategies.