In this study, the exposure risk of characteristic pollutants in contaminated soil entering human body through three main exposure routes was considered, including oral exposure [TCRo, mg/(kg d)], skin exposure [TCRd, mg/(kg d)] and respiratory exposure [TCRi, mg/(kg d)], which can be expressed by the following formula: (/kloc-
CDI soil = TCRO+TCRD+TCRI (12.15)
Study on the protection and sustainable utilization of water resources under changing environmental conditions
Study on the protection and sustainable utilization of water resources under changing environmental conditions
Study on the protection and sustainable utilization of water resources under changing environmental conditions
See table 12.4 1 and table 12.42 for the meanings of each factor in the formula. The concentration of characteristic pollutants in the site soil should be determined according to the test results of the highest concentration of soil sampled at the site during this exploration and construction period; According to the weight and height, the total skin surface area of children and adults is 6 127cm2 and 16603cm2 respectively (total skin surface area /m2=0.0239× height /cm0.4 17× weight /kg0.5 17). For industrial land, 26% of the total skin surface area (head 6%, upper limbs and arms 6%, hands 4%, legs and feet 10%) may be exposed to soil characteristic pollutants, and the skin areas of children and adults are 1593cm2 and 43 17cm2 respectively.
Table 12.4 1 Evaluation Parameter Table of Soil Pollution Health Risk Assessment Model
The daily air respiration of respiratory intake exposure route refers to the values of the United States and Canada, and the air intake of children and adults is defined as 10 and 20m3/d respectively. Other exposure parameters, such as skin adhesion factors (AFa and AFc) of adults and children, skin absorption factors (ABS) of characteristic pollutants and soil particle diffusion factors (PEF), refer to the default values of the US Environmental Protection Agency and some states.
12.6.3.2 evaluation coefficient
The selection of groundwater pollution risk assessment factors in this work refers to the initial value specified in Appendix A of Technical Guidelines for Risk Assessment of Contaminated Sites (draft for approval) and the factors detected in this work, namely naphthalene, acenaphthene, fluorene, anthracene, fluoranthene, pyrene, benzo [a] anthracene, aniline, benzo [b] fluoranthene and benzo [b] fluoranthene.
The detection value of the highest evaluation substance in each hole is taken as the reference value of this risk assessment (Table 12.42).
Table 12.42 Determination Table of Soil Pollution Risk Assessment Value
Analysis of evaluation results
Input the key parameter values into the MMSOILS model, and calculate the health risk value of soil pollution in the gas station site between (2.4 ~ 1.6) × 10-3, in which the health risk value at ZK 1 is the largest, with 2.4, and that at ZK4 is the smallest, with13. Figure 12.60).
Table 12.43 Soil Pollution Risk Assessment Results Table
Figure 12.60 histogram of contribution value of comprehensive soil pollution risk in gas station
At the same time, the source analysis of health risk values at each point (Figure 12.6 1 ~ Figure 12.65) shows that the main cause of cancer caused by soil pollution comes from oral contaminated soil, and the risk of cancer caused by inhalation of soil particles and skin contact with contaminated soil is relatively low.
Figure 12.6 1 gas station ZK 1 hole soil pollution risk contribution value histogram
Figure 12.62 Histogram of soil pollution risk contribution value in ZK2 hole of gas station
Figure 12.63 Histogram of soil pollution risk contribution value in ZK3 hole of gas station
Figure 12.64 Histogram of soil pollution risk contribution value in ZK4 hole of gas station
Figure 12.65 Histogram of soil pollution risk contribution value in ZK5 hole of gas station
At the same time, the source analysis of health risk values at each point (Figure 12.66 ~ Figure 12.70) shows that the main cause of cancer caused by soil pollution is oral inhalation of contaminated soil, and the risk of cancer caused by inhalation of soil particles and skin contact with contaminated soil is relatively low.
Figure 12.66 Pie Diagram of Soil Pollution Risk Structure of Gas Station ZK 1 Hole
Figure 12.67 Pie Diagram of Soil Pollution Risk Structure in ZK2 Hole of Gas Station
Figure 12.68 Pie Diagram of Soil Pollution Risk Structure in ZK3 Hole of Gas Station
The maximum total health risk of site soil pollution to this area is 2.4, which is far greater than the human health risk value 10-6 recommended by the US Environmental Protection Agency. It also exceeds the upper limit of the risk level 10-4 that the US Environmental Protection Agency thinks can be tolerated when repairing contaminated sites. Therefore, according to the carcinogenic risk assessment, the contaminated site is in the stage of urgent need of environmental treatment.
Figure 12.69 Pie Diagram of Soil Pollution Risk Structure in ZK4 Hole of Gas Station
Figure 12.70 Pie Diagram of Soil Pollution Risk Structure in ZK5 Hole of Gas Station
From the above analysis, it can be concluded that the soil in this site has been seriously polluted, and it is urgent to treat the contaminated soil.