## 3 Results and Discussion
### Assessing the Health Risks Associated with the PTEs
#### 3.4.2 Carcinogenic Risks to Humans  
Only the carcinogenic risks of As, Cd, Cr, Ni, and Pb to humans is examined in this chapter because only the carcinogenic slope factors of these researched PTEs have been previously determined in the literature. Table 8 shows the median values of carcinogenic risk assessment indictors, such as CDI and CR, for individually documented PTEs by individual routes, TCR for individual PTEs by total pathways, and CTCR for the cumulative values of these recorded PTEs by the total three pathways. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & & **As** & **Cd** & **Cr** & **Cu** & **Hg** & **Ni** & **Pb** & **Zn** \\ \  
Similar to non-carcinogenic risk, the median values of the carcinogenic CDI for all of the studied PTEs by direct oral ingestion was much higher than that by dermal contact and respiratory inhalation. The median values of the daily carcinogenic exposure of the three different pathways were ranked as follows: \(\mathrm{CDI}_{\mathrm{ingestion}}>\mathrm{CDI}_{\mathrm{dermal}}>\mathrm{CDI}_{ \mathrm{inhalation}}\). Only the carcinogenic slope factors of As and Cr were provided by direct oral ingestion. Children have a substantially higher carcinogenic risk from As and Cr exposure than adults. Adults have higher carcinogenic hazards than children when it comes to respiratory inhalation and dermal contact. For children, the order of the median values of carcinogenic risk for the sum of the documented PTEs from the three overall pathways was as follows: As \(>\) Cr \(>\) Pb \(>\)Ni \(>\) Cd, and for adults, it was As \(>\) Cr \(>\) Ni \(>\)Pb \(>\) Cd. The carcinogenic risk of children to all of the documented PTEs by the total pathways were higher than that of adults. When considering all of the sample points of the study area, the carcinogenic risk by oral ingestion were considered to be acceptable for As (1532 sites, counting for 97.33%) and Ni (1571 sites, counting for 99.81%) for children and As (1561 sites, counting for 99.17%) and Ni (1569 sites, counting for 99.68%) for adults, respectively. Additionally, the carcinogenic risks of one site for As and three sites for Cr to children, and two sites for As and five sites for Cr to adults were considered to be negligible. For As, only 41 sites (2.60%) and 11 sites (0.70%) represented an unacceptable carcinogenic risk to children and adults via the oral ingestion pathway, respectively. For inhalation, all of the sites represented a negligible carcinogenic risk to both children and adults. With the exception of 2.67% (42 sites) and 0.76% (12 sites) of As, which pose a carcinogenic risk to children and adults, respectively, all of the other known PTEs pose a negligible or acceptable carcinogenic risk through all three pathways. In terms of the cumulative carcinogenic risk of all of the recorded PTEs via the three total pathways, 3.24% (51 sites) and 0.83% (13 sites) were considered to be unacceptable for children and adults, respectively. Arsenic contributed the most to the carcinogenic risk of all of the PTEs (Table 9). Contour maps determined by IDW interpolation are presented to find the carcinogenic risk distributions of As and all of the PTEs via the three pathways (Figure 8). The distribution of places with unacceptable carcinogenic risk coincides with the distribution of Hg and Cu-Pb-Zn deposits, just as it does with non-carcinogenic risk. In addition, As had the highest slope factor of all of the examined PTEs, meaning that it poses the highest carcinogenic risk to humans. Although the overall carcinogenic risk in the study area is acceptable, residents living near the mine should be aware of the potential carcinogenic risk of all of the PTEs.