[Environmental Health Risk Assessment of Contaminated Soil Based on Monte Carlo Method: A Case of PAHs]

In order to obtain more reasonable health risk values and get the most significant factors, probabilistic risk models based on Monte Carlo simulation were applied, the health risk level of 16 PAHs in soil was evaluated for a residential area in Shanghai, China. And, sensitivity analysis was conducted for each parameter. The results showed that, the health risks caused by PAHs followed lognormal distribution with 3.43×10^-5±2.63×10^-5 for carcinogenic risk, which was between 8.10×10^-7 and 2.39×10^-4 and the probabilities exceeding 10^-6, 10^-5 and 10^-4 were 95%, 75% and less than 5%. And the value was 4.74×10^-2±3.42×10^-2 for hazard quotient, which was between 1.38×10^-3 and 2.85×10^-1 and less than 1, so could be regarded negligible. As for total carcinogenic risk (TCR), the most influential PAHs were BaP, DBA and BaA, and their contribution rates were 60.41%, 26.84% and 6.56%, respectively. Among the three exposure pathways, the risk was mainly caused by oral intake with the contribution rate of 73.22%, followed by dermal contact with 26.51%. The most influential parameters were:intake amount of soil per day, exposure duration and exposed skin area with the sensitivity values of 58.35%, 50.21% and 20.51%, respectively. And body weight had a negative sensitivity with -11.66%. When it came to total hazard quotient (THQ), Pyr, FL and PA accounted for the most with 36.56%, 33.18% and 13.18%, respectively. And the oral intake and dermal contact were also primary exposure pathways with 72.21% and 26.36%. The most significant parameters were the same with TCR with the sensitivity values of 63.52%, 53.18%, 24.39% and -13.98%, respectively.