Assessing biological biomarkers is essential for evaluating the impact of environmental pollution. In this study we examine the effects of heavy metal contamination on erythrocyte genotoxicity, oxidative stress, and body condition of Perrin’s green toads (Bufotes perrini) collected from two aquatic habitats—Golestan National Park (GNP) and its adjacent agricultural area. A total of 72 toads were analyzed for concentrations of heavy metal ions, including Pb(II), Cd(II), As(V), Zn(II), Cr(III), and Cu(II), in liver tissue. The results showed significantly elevated concentrations of heavy metals in toads collected in the agricultural area compared to those collected within GNP (P < 0.05), with Zn and Cu being the primary contributors to the observed differences. Blood cell nuclear abnormalities, including micronuclei and apoptotic cells, were more prevalent in the agricultural area (P < 0.05). Additionally, increased malondialdehyde (MDA) levels, indicative of oxidative stress (P < 0.05), and a lower residual index in toads from the agricultural area were observed (P < 0.05). A significant positive correlation was found between heavy metal concentrations, nuclear abnormalities, MDA levels, and reduced body condition, indicating that heavy metal contamination negatively affects both the genetic health and physical condition of toads. Given that amphibians are bioindicators of polluted ecosystems, this study underscores the importance of physiological biomarkers in determining the pollution status of distinct habitats with different pollution levels, offering insights for conservation strategies.
