In situ assessment of genetic and epigenetic alterations in frog Rana plancyi and Rana limnocharis inhabiting aquatic ecosystems associated with Pb/Zn/Cu mining

Exploration for metallic minerals leads to severe trace metal contamination, thus the ecological risk to aquatic organisms near mining regions has attracted widespread attention. In this study, two species of frog Rana plancyi and Rana limnocharis were collected as amphibian models to explore the genetic and epigenetic effects of trace metals in Dexing mining region. The results indicated that the surface water was heavily contaminated with trace metals and the two species of frog have high bioconcentration of trace metals in the liver. Trace metals disrupted the redox balance and increased reactive oxygen species levels. DNA strand breaks and increased 8hydroxy-2 '-deoxyguanosine levels were observed in the genomic DNA of frogs. Global DNA hypomethylation was found in the liver, which indicated adverse epigenetic effects on frogs. Overall, the study demonstrated that there was significant genotoxicity and epigenotoxicity of aquatic organisms living around the mining region. DNA damage and global DNA methylation are promising biomarkers for assessment of the ecological risk of trace metal pollution in aquatic amphibian frogs. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study showed that surface water in the Dexing mining region is heavily contaminated with trace metals, resulting in bioaccumulation of trace metals in the liver of two frog species. Genotoxic and epigenotoxic effects were observed in the genetic and epigenetic levels, indicating significant ecological risks for aquatic organisms near the mining region. DNA damage and global DNA methylation levels can serve as promising biomarkers for assessing the ecological risk of trace metal pollution in aquatic amphibian frogs.