Using Non-destructive Techniques to Measure Mercury (Hg) Concentrations in Gravid Blanding’s Turtles (Emydoidea blandingii) in Northeastern Illinois

Abstract

Aquatic turtles are suitable biomonitors of wetland ecosystem health because they are long-lived and occupy elevated trophic positions in wetland food webs. This study aimed to determine Hg exposure in adult Blanding’s turtles (Emydoidea blandingii), an imperiled prairie-wetland species endemic to the northern U.S. and southern Canada. Claw samples were collected from gravid females from four wetland sites in northeast Illinois. Claw Hg concentrations ranged from 654 to 3132 ng/g and we found no effect of body size (carapace length, CL) and some evidence for an effect of wetland site (WS) on mean Hg (i.e. weak effect of site on Hg, detected between WS1 and WS3). Claw Hg concentrations reported in this study were lower than claw concentrations published for other freshwater turtles (e.g. Chelydra serpentina, Sternotherus oderatus). This is the first Hg-related study on Blanding’s turtles and can serve as a reference for other Hg studies in Illinois wetlands.