Application Of QSAR-PBPK Model To Research Of Children's Health Risk Of Mixture Of Trihalomethanes From Reclaimed Water In Toilets

To solve the problem of water shortage,the application of reclaimed water is increasingly widespread and the potential health risk of using reclaimed water is paid more attention.Meanwhile,children are more vulnerable and susceptible than adults,and children are always ignored in study of health risk assessment.Therefore,it's extremely essential that establishing an available health risk assessment system of reclaimed water for children.This study built health risk assessment model of children using reclaimed water in toilets,and supported risk management of reclaimed water in method.Trihalomethanes(THMs)were detected termly,the results showed that concentrations of four different THMs obeyed logarithmic normal distribution,and concentration of trichloromethane was highest,followed by bromodichloromethane,dibromochloromethane,tribromethane.Then three-compartment model was adjusted and simplified to establishe the indoor contaminant volatilization model and physiologically based pharmacokinetic(PBPK)model for children.To evaluate some biochemical parameters and partition coefficients of children,quantitative structure-activity relationships(QSAR)models were established.Subsequently,using QSAR-PBPK model simulated distributing and metabolizing of THMs inside children.Then utilizing the simulation results of these models,children total health risk of THMs from reclaimed water in toilets was calculated by software named Crystal Ball which was based on Monte Carlo method.The total health risk of THMs based on QSAR-PBPK models was compared with risk estimated traditional method,we reached the following conclusions:1.Health risk of children from using reclaimed water was higher than the risk of adults according to some existed researches.So vulnerable and susceptible crowd such as children,oldster should be paid more attention in the field of health risk assessment.2.The children's total health risk of THMs calculated based on QSAR-PBPK models was higher than the risk calculated by traditional method,and the total health risk of THMs from children who used reclaimed water to flush toilets was higher than acceptable risk level.Finally,this paper gave some advices for health risk management of children using reclaimed water in toilets and proposed solution according to calculating and analyzing result.