## 3 Results and Discussion
### Exposure Dose of Heavy Metals  
Table 3 presents the P50-P95 exposure dose of Cd in different age groups. The highest Cd exposure dose was found in water spinach in different age groups of the Taiwan population, except for 0-3 years old. However, the highest exposure dose for 0-3 years was in sweet potato (0.0027-0.0086 mg/kg b.w./day), because sweet potato can be used as a by-product formula for infants and young children and, so, for the intake of this age group, is larger when compared to other types of vegetable.  
Table 4 shows P50-P95 of Cu exposure doses from consuming vegetables in different age groups. The highest exposure dose for Cu was found in 0-3 years old for consuming sweet potato (0.0043-0.0137 mg/kg b.w./day). The highest exposure doses in the different age groups were not consistent, possibly because the Cu concentrations in water spinach, potato, and sweet potato are not significantly different.  
Table 5 shows the P50-P95 of hazard quotient (HQ) for Cd from consuming different vegetables. The levels for 0-3 years old were 4.80-11.6 (all HQs being >1), while all HQs for Cu were <1 (Table 6). The intake of water spinach was identified as a major contributor to the estimated daily intake of two metals by the residents. Many researchers have identified that vegetables that are cultivated in soil with metals can pose a potential health risk for consumers [20,49,57], but [PERSON] et al. [58] suggested that the concentrations of metals decreased in the order: leafy vegetables > stalk vegetables/root vegetables/solanaceous vegetables > legume vegetables/melon vegetables. The current study also provided evidence of the risk within the safe range when consuming sweet potato leaf, potato, or tomato, indicating that the high accumulators (leafy vegetables) were unsuitable for being planted on contaminated soil.  
\begin{table}
\begin{tabular}{c c c c c c} \hline
**Age** & **Water Spinach** & **Sweet Potato Leaf** & **Potato** & **Sweet Potato** & **Tomato** \\ \hline
0–3 & 0.0013–0.0042 & 0.0005–0.0017 & 0.0016–0.0051 & 0.0043–0.0137 & 0.0015–0.0049 \\
3–6 & 0.0013–0.0040 & 0.0005–0.0016 & 0.0011–0.0032 & 0.0008–0.0023 & 0.0020–0.0061 \\
6–12 & 0.0017–0.0057 & 0.0007–0.0022 & 0.0035–0.0113 & 0.0011–0.0037 & 0.0013–0.0042 \\
12–16 & 0.0008–0.0026 & 0.0003–0.0011 & 0.0024–0.0077 & 0.0004–0.0013 & 0.0010–0.0031 \\
16–18 & 0.0012–0.0038 & 0.0005–0.0015 & 0.0017–0.0052 & 0.0004–0.0014 & 0.0007–0.0022 \\
19–65 & 0.0023–0.0067 & 0.0009–0.0027 & 0.0009–0.0026 & 0.0006–0.0017 & 0.0015–0.0046 \\ >65 & 0.0031–0.0093 & 0.0012–0.0037 & 0.0011–0.0034 & 0.0008–0.0024 & 0.0011–0.0034 \\ \hline \end{tabular}
\end{table}
Table 4: 50 th–95 th percentile of dietary exposures (mg/kg b.w./day) to Cu by consuming vegetables in all age groups.  
\begin{table}
\begin{tabular}{c c c c c c} \hline
**Age** & **Water Spinach** & **Sweet Potato Leaf** & **Potato** & **Sweet Potato** & **Tomato** \\ \hline
0–3 & 0.0014–0.0043 & 0.0001–0.0003 & 0.0001–0.0003 & 0.0027–0.0086 & 0.0001–0.0005 \\
3–6 & 0.0014–0.0042 & 0.0001–0.0003 & 0.0001–0.0002 & 0.0005–0.0014 & 0.0002–0.0006 \\
6–12 & 0.0018–0.0058 & 0.0001–0.0004 & 0.0002–0.0006 & 0.0007–0.0022 & 0.0001–0.0004 \\
12–16 & 0.0009–0.0028 & 0.0001–0.0002 & 0.0001–0.0004 & 0.0003–0.0008 & 0.0001–0.0003 \\
16–18 & 0.0013–0.0039 & 0.0001–0.0003 & 0.0001–0.0003 & 0.0003–0.0008 & 0.0001–0.0002 \\
19–65 & 0.0024–0.0070 & 0.0002–0.0005 & 0.0000–0.0002 & 0.0004–0.0011 & 0.0001–0.0004 \\ >65 & 0.0033–0.0097 & 0.0002–0.0006 & 0.0001–0.0002 & 0.0005–0.0016 & 0.0001–0.0003 \\ \hline \end{tabular}
\end{table}
Table 3: 50 th–95 th percentile of dietary exposures (mg/kg b.w./day) to Cd by consuming vegetables in all age groups.