It's not all about PFAS: Metal(loid)s are associated with physiological and metabolic changes in a native frog from conservation wetlands

Abstract

Urban wetlands provide essential habitats for wildlife but face increasing contamination from anthropogenic sources, including but not limited to per- and polyfluoroalkyl substances (PFAS) and metal(loid)s. Accumulation of these contaminants are known to impair organism biological functions. This study quantified PFAS and metal(loid) concentrations in liver tissue of motorbike frogs (Ranoidea moorei) along a contamination gradient of conservation significant urban wetlands in Perth, Western Australia, and assessed relationships of liver concentrations with whole-organism health metrics and metabolomic profiles in four tissues to evaluate biological effects. Of 61 accepted PFAS in frog livers, 22 had at least one individual above reporting limit. Linear perfluorooctane sulfonate (PFOS) was the most abundant PFAS compound in frog livers and males had higher PFAS concentrations at larger body sizes. The total PFAS concentrations in motorbike frog livers (range: 1.3–145.7, outlier: 364.3 μg/kg) were relatively low compared to tertiary consumer species or those inhabiting heavily contaminated sites. Total PFAS concentrations, or interactions between total PFAS and metal(loid)s, were not significantly correlated with body condition, liver mass, or gross health indicators; however, there were subtle tissue-specific metabolic perturbations linked to PFAS exposure, particularly in males. Biological responses showed stronger associations with liver concentrations of Zn (range: 13.7–90 mg/kg), Se (range: <0.05–4.1 mg/kg), and Cu (range: 11.3–248.5 mg/kg). Zinc concentrations were negatively associated with body condition, and females showed greater muscle metabolic perturbation while males had more metabolic associations in fat tissue. Selenium concentrations exhibited a biphasic relationship with body condition, with males showing Se-associated metabolic changes in the liver and fat. Copper concentrations were inversely associated with liver mass, with females exhibiting higher Cu levels and greater metabolic disruption. This study integrates metabolomics with traditional health assessments to better understand how anthropogenic and naturally occurring contaminants influence amphibian health.