# Human Exposure to Toxic Metals (Cd, Pb, Hg) and Nitrates (NO3-) from Seaweed Consumption
## 3 Results and Discussion  
### Concentration and Dietary Intake of Toxic Metals (Cd, Pb, Hg)  
Tables 4-6 show the mean concentrations (mg/kg dry weight/dw), standard deviations (SD), and the dietary intake assessment of the toxic metals (Cd, Pb, Hg) in the analyzed algae. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Origin** & **Species** & **Concentration \(\pm\) SD (mg/kg)** & **EDI (\(\text{ug}\)/day)** &
\begin{tabular}{c} **Contribution to** \\ **TWI (\%)** \\ \end{tabular} \\ \hline \multirow{4}{*}{Asia} & _Hijiki_ & 1.196 \(\pm\) 0.234 & 4.78 & 19.6 \\  & _Nori_ & 1.005 \(\pm\) 0.897 & 4.02 & 16.4 \\  & _Kombu_ & 0.417 \(\pm\) 0.484 & 1.67 & 6.82 \\  & _Wakame_ & 0.753 \(\pm\) 0.463 & 3.01 & 12.3 \\ \hline \multirow{4}{*}{Europe} & _Sen spaghetti_ & 0.020 \(\pm\) 0.032 & 0.08 & 0.33 \\  & _Kombu_ & 0.085 \(\pm\) 0.096 & 0.34 & 1.39 \\  & _Sea lettuce_ & \textless{LOO} & & - \\  & _Starry moss_ & \textless{LOQ} & & - \\  & _Nori_ & 0.011 \(\pm\) 0.00 & 0.044 & 0.18 \\  & _Wakame_ & 0.070 \(\pm\) 0.096 & 0.28 & 1.14 \\  & _Arame_ & 0.082 \(\pm\) 0.125 & 0.328 & 1.34 \\  & _Mixed salad_ & 0.198 \(\pm\) 0.137 & 0.792 & 3.24 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Cadmium concentrations, estimated intake (EDI), and percentage contribution to the guideline value of the analyzed algae. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Origin** & **Species** & \
\begin{tabular}{c} **Concentration \(\pm\)** \\ **SD (mg/kg)** \\ \end{tabular} & **EDI (\(\text{ug}\)/day)** &
\begin{tabular}{c} **Contribution to** \\ **TWI (\%)** \\ \end{tabular} \\ \hline \multirow{4}{*}{Asia} & _Hijiki_ & 0.004 \(\pm\) 0.001 & 0.016 & 0.04 & 0.02 \\  & _Nori_ & 0.018 \(\pm\) 0.019 & 0.072 & 0.17 & 0.07 \\  & _Kombu_ & 0.071 \(\pm\) 0.070 & 0.284 & 0.66 & 0.28 \\  & _Wakame_ & 0.119 \(\pm\) 0.071 & 0.476 & 1.10 & 0.46 \\ \hline \multirow{4}{*}{Europe} & _Sea spaghetti_ & 0.020 \(\pm\) 0.032 & 0.08 & 0.19 & 0.08 \\  & _Kombu_ & 0.041 \(\pm\) 0.077 & 0.164 & 0.38 & 0.16 \\  & _Sea lettuce_ & \textless{LOQ} & & - & \\  & _Starry moss_ & \textless{LOQ} & & - & \\  & _Nori_ & 0.011 \(\pm\) 0.00 & 0.044 & 0.10 & 0.04 \\  & _Wakame_ & 0.007 \(\pm\) 0.007 & 0.028 & 0.06 & 0.03 \\  & _Arame_ & 0.047 \(\pm\) 0.008 & 0.188 & 0.44 & 0.18 \\  & _Mixed salad_ & 0.016 \(\pm\) 0.013 & 0.064 & 0.15 & 0.06 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Lead concentrations, estimated intake (EDI), and percentage contribution to the guideline value of the analyzed algae. Cd is noteworthy for its high concentrations, and its content in Asian algae is worth mentioning, especially in hiijki (1.196 mg/kg) and nori (1.005 mg/kg) (Table 4). According to the EFSA, the Cd levels in some seafoods are remarkable. The levels of Cd in oysters (0.2350 mg/kg), bivalve mollus (0.163 mg/kg), and limpets (0.180 mg/kg) stand out [10]. However, the Cd concentrations recorded in some seaweed samples are higher than the average Cd levels in some seafoods reported by EFSA. Regarding Pb, the highest concentrations obtained also correspond to algae from Asian countries, in this case, wakame algae (0.119 mg/kg) (Table 5). The case of Hg is not the same since the highest mean average content was found in European algae, arame algae (0.055 mg/kg) (Table 6). Figure 1 shows the comparison of the content of the three analyzed metals between Europe and Asia. It can clearly be seen that, in all cases, the concentrations of the three toxic metals are higher in Asia than in Europe (without differentiating between species). In addition, the statistical study revealed the existence of significant differences (\(p<0.05\)) in the content of these metals between both origins.