# Risk Assessment of Metals in Black Fungus and Culture Substrates Based on Monte Carlo Simulation
## 3 Results
### Risk Assessment of Dietary Exposure to Heavy Metals in Black Fungus
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{\begin{tabular}{c} **Sample** \\ **Class** \\ \end{tabular} } & \multirow{2}{*}{**Element**} & \multirow{2}{*}{**Average Content**} & \multirow{2}{*}{\begin{tabular}{c} **Minimum** \\ **Value** \\ **mg/kg** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Maximum** \\ **Value** \\ **mg/kg** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Median** \\ **mg/kg** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Limit** \\ **Value** \\ **mg/kg** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Detection** \\ **Ratio** \\ **mg/kg** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Over Standard** \\ **Ratio** \\ **\%** \\ \end{tabular} } \\ \hline \multirow{4}{*}{Medium} & As & 0.349 \(\pm\) 0.122 & 0.185 & 0.493 & 0.317 & 0.8 & 100 & 0 \\  & Pb & 0.380 \(\pm\) 0.278 & 0.030 & 1.053 & 0.329 & 35 & 100 & 0 \\  & Cd & 0.048 \(\pm\) 0.024 & 0.007 & 0.092 & 0.048 & 0.3 & 100 & 0 \\  & Cr & 2.078 \(\pm\) 2.046 & 0.489 & 7.352 & 1.434 & / & 100 & / \\ \hline \multirow{4}{*}{\begin{tabular}{c} Waste fungus \\ stick \\ \end{tabular} } & As & 0.522 \(\pm\) 0.215 & 0.110 & 0.868 & 0.540 & 0.8 & 100 & 6.25 \\  & Pb & 0.669 \(\pm\) 0.343 & 0.070 & 1.309 & 0.711 & 35 & 100 & 0 \\  & Cd & 0.146 \(\pm\) 0.103 & 0.052 & 0.455 & 0.095 & 0.3 & 100 & 9.38 \\  & Cr & 1.898 \(\pm\) 1.064 & 0.513 & 4.252 & 1.658 & / & 100 & / \\ \hline \multirow{4}{*}{\begin{tabular}{c} Saw dust \\ \end{tabular} } & As & 0.122 \(\pm\) 0.142 & 0.038 & 0.447 & 0.060 & 0.8 & 100 & 0 \\  & Pb & 0.783 \(\pm\) 0.430 & 0.053 & 1.583 & 0.835 & 35 & 100 & 0 \\  & Cd & 0.079 \(\pm\) 0.057 & 0.009 & 0.272 & 0.061 & 0.3 & 100 & 0 \\  & Cr & 2.797 \(\pm\) 2.935 & 0.894 & 14.788 & 1.696 & / & 100 & / \\ \hline \multirow{4}{*}{\
\begin{tabular}{c} Bean pulp \\ \end{tabular} } & As & 0.019 \(\pm\) 0.017 & 0.010 & 0.019 & 0.018 & 0.8 & 100 & 0 \\  & Pb & 0.097 \(\pm\) 0.101 & 0.016 & 0.372 & 0.055 & 35 & 100 & 0 \\  & Cd & 0.050 \(\pm\) 0.038 & 0.011 & 0.120 & 0.037 & 0.3 & 100 & 0 \\  & Cr & 0.504 \(\pm\) 0.345 & 0.133 & 1.329 & 0.338 & / & 100 & / \\ \hline \multirow{4}{*}{
\begin{tabular}{c} Rice chaff \\ \end{tabular} } & As & 0.736 \(\pm\) 0.106 & 0.647 & 0.905 & 0.684 & 0.8 & 100 & 20 \\  & Pb & 0.705 \(\pm\) 0.360 & 0.005 & 1.515 & 0.820 & 35 & 100 & 0 \\ \cline{1-1}  & Cd & 0.037 \(\pm\) 0.026 & 0.011 & 0.095 & 0.031 & 0.3 & 100 & 0 \\ \cline{1-1}  & Cr & 3.265 \(\pm\) 1.901 & 0.582 & 7.084 & 2.486 & / & 100 & / \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Concentrations of heavy metal residues in different culture substrates. 4.2 Comparative Analysis of Simulated Distribution of Heavy Metals in Black Fungus Cultivation Medium  
In this study, the distribution of residual heavy metals in the samples of different cultivation substrates was simulated, and each simulation process was cycled 10,000 times. The results of the simulation distribution of residual heavy metals in different cultivation substrates showed that the residual concentrations were low and some extreme values existed. Supplemental Figure S1 shows that the maximum, minimum and average As content in the simulated medium was 1.303 mg/kg, 0 mg/kg, and 0.132 mg/kg. The 90% confidence interval was mainly distributed in the range of 0.007-0.396 mg/kg. The maximum content of Pb was 1.147 mg/kg, the minimum value was 0.030 mg/kg, and the average value was 0.405 mg/kg. The 90% confidence interval was mainly distributed in the range of 0.059-0.902 mg/kg. The maximum value of Cd was 0.104 mg/kg, the minimum value was 0 mg/kg, and the average value was 0.047 mg/kg. The 90% confidence interval was mainly distributed in the range of 0.013-0.086 mg/kg. The maximum value of Cr was 13.665 mg/kg, the minimum value was 0 mg/kg, and the average value was 1.385 mg/kg. The 90% confidence interval was mainly distributed in the range of 0.020-4.250 mg/kg. And Cr > Pb > As > Cd.