## 2 Results
### Suffide and Thiol Measurement in Plasma  
Based on the data presented in Figure 1, individuals characterized by low ferritin levels exhibited significantly lower levels of endogenous sulphide-H\({}_{2}\)S in their plasma in comparison to individuals with normal ferritin levels (* \(p\) < 0.05). Furthermore, individuals belonging to Group B, who reported frequent exposure to environmental H\({}_{2}\)S, demonstrated significantly higher levels of sulfide-H\({}_{2}\)S in their plasma compared to individuals in Group A, who reported sporadic exposure to H\({}_{2}\)S. Notably, it was observed that individuals with low ferritin levels residing in the surrounding area, who were frequently exposed to environmental H\({}_{2}\)S, exhibited significantly higher levels of sulfide-H\({}_{2}\)S in their plasma when compared to individuals with low ferritin levels in Group A, who had sporadic H\({}_{2}\)S exposure (# \(p\) < 0.05). According to the data shown in Figure 2, no significant difference in total thiol levels was observed between individuals with low and normal ferritin in group A, who had sporadic exposure to H\({}_{2}\)S. However, individuals with low- ferritin levels displayed significantly higher total thiol levels compared to those with normal ferritin levels (* \(p\) < 0.05). Additionally, a significant decrease in total thiol levels was observed when comparing Group B, characterized by frequent exposure to environmental H\({}_{2}\)S, to Group A (* \(p\) < 0.05). \begin{table}
\begin{tabular}{c c c c c} \hline  & \multicolumn{2}{c}{**Group A (Control Area)**} & \multicolumn{2}{c}{**Group B (Exposed to H\({}_{2}\)S Area)**} \\ \hline
**Age** & **37** & **38** & **40** & **40** \\ \hline
**Gender** & Female: 89 & Female: 81 & Female: 77 & Female: 86 \\  & Male: 11 & Male: 19 & Male: 23 & Male: 14 \\ \hline
**Ferritin levels (ng/mL)** & 6.57 \(\pm\) 0.22 & 87.51 \(\pm\) 4.99 & 6.18 \(\pm\) 0.32 & 91.65 \(\pm\) 0.22 \\ \hline
**Number of visits (times/year) *** & \(\sim\)2–3 & \(\sim\)2–3 & \(\sim\)10–12 & \(\sim\)10–12 \\ \hline
**Duration of each visit (hrs) *** & \(\sim\)2–3 & \(\sim\)2–3 & \(\sim\)2–3 & \(\sim\)2–3 \\ \hline \end{tabular}  
* Noting that exposed individuals live in the thermal spring’s surrounding area, the times represented in the table are the average number of visits to the spring spa to soak.  
\end{table} 
Table 1: Ferritin levels and visitation patterns to thermal springs for individuals who participated in this study. Figure 1: The impact of environmental H\({}_{2}\)S exposure on endogenous H\({}_{2}\)S plasma levels in individuals with low and normal ferritin status. The values are reported as the mean \(\pm\) standard deviation. The symbol “#” indicates a significant difference at \(p\) < 0.05 when comparing the low-ferritin group who were not exposed to H\({}_{2}\)S. The symbol “*” indicates a significant difference at \(p\) < 0.05 when comparing the normal ferritin group to the low-ferritin group in the group A, which had not been exposed to H\({}_{2}\)S. Group A refers to individuals who were not exposed to environmental H\({}_{2}\)S, while group B refers to individuals who were exposed to environmental H\({}_{2}\)S.  
Figure 2: The impact of environmental H\({}_{2}\)S exposure on plasma thiol (SH) levels in individuals with low and normal ferritin status. The values are reported as the mean \(\pm\) standard deviation.