Study On Parameter Sensitivity Of Health Risk Assessment Model Of Contaminated Plot

In this paper,taking a chemical polluted land as an example,the revised parameters were used to carry out a stratified health risk assessment on the land,and the risk and control values before and after the parameter modification were compared and analyzed.The influence of parameter changes on risk level was analyzed by changing parameter values,and then the sensitivity of parameters was studied and the causes were analyzed.Specific research results are as follows:(1)After parameter modification,the risk ratio decreases and the risk control value increases.For risk,the change proportion of vinyl chloride was the smallest,7%,and the change proportion of benzene was the largest,93%.For the control value,the change proportion of ammonia was the smallest,which was 9.49%,and the change proportion of vinyl chloride was the largest,which was 372.11%.Before and after parameter modification,the main exposure pathway of each pollutant remained unchanged,and the change of contribution rate was small,indicating that the assessment results were credible.(2)The pollutants are divided into heavy metals,VOCs and SVOCs.With the increase of various parameters,there are three kinds of situations: rising,falling and no change.When the population and air parameters increased,the risk of heavy metals changed,while the risk of heavy metals did not change when the other parameters increased.As the population and pollution zone parameters increased,the risk increased overall.As soil,groundwater,buildings,and air parameters increase,risk decreases overall.(3)Compared with the sensitivity of similar parameters,the same parameter may have different sensitivity to the same type of pollutant.For example,the exposure frequency is sensitive to arsenic but not to cadmium.In addition,the sensitivity evaluation results may be different with different criteria,such as carcinogenic risk as the evaluation standard,exposure frequency is not sensitive to cadmium,and hazard quotient as the standard sensitivity.The reason is that the physical and chemical properties of various substances are different,which is reflected in parameters and calculation methods.(4)Comparing the sensitivity of various parameters,the sensitivity of parameters to different types of pollutants is different.For heavy metals,population parameters were sensitive,but the other five parameters were not sensitive.For VOCs,the population,soil and building parameters are sensitive,the polluted area and air parameters are not sensitive,and the groundwater parameters are generally sensitive.For SVOCs,the parameters of population,soil and groundwater are sensitive,the parameters of polluted areas and buildings are not sensitive,and the sensitivity of air parameters is general.(5)The sensitivity of the parameters was positively correlated with the risk contribution rate of the exposure route.The greater the risk contribution rate of the exposure path of a parameter is,the greater the probability of its sensitivity is;otherwise,it is not sensitive.For example,soil organic matter content is in the path of inhaling indoor lower layer soil steam,and the risk contribution rate of benzene from this path exceeds 80%,so soil organic matter content is sensitive to benzene.There are 38 figures,31 tables and 86 references in this paper.