First evaluation and ecological risk of potentially toxic elements in the formations of Akçakale cave (Gümüşhane-NE-Türkiye)

In this study, the potential toxic element levels (PTEs) and adverse health effects of Akçakale cave formations were evaluated using geochemical parameters such as enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF), ecological risk factor (\({E}_{r}^{i}\)), potential ecological risk index (PERI), and non-carcinogenic hazard index (HI). Water does not pose a pollution risk, as the concentrations of potentially toxic elements in all samples are within the permissible limits for drinking water. According to the calculated geochemical parameters, all the samples were polluted with As, Co, Ni, Cu, V, and Pb. Ni, As, Cu, and Pb show very high ecological risk (PER > 320) in all samples, except Cu and Pb in T2T. The PERI values of the PTEs were more than 600 in all samples, indicating a very high potential ecological risk. The HI > 1 values for Co and As in all samples for both adults and children suggested potential non-carcinogenic health risks from exposure to these elements in the cave environment. The PTEs in the Akçakale cave formation were most likely linked to lithogenic, geogenic (Pb–Zn-Cu mineralization), and anthropogenic (agricultural activities) processes, per the findings of the data analysis using multivariate statistics (PCA and PCC). These data obtained are the first findings regarding the potential toxic element content of Akçakale cave.