Study On The Relationship Between Integrated Exposure To Polycyclic Aromatic Hydrocarbons And Lung Cancer Mortality Rate

Polycyclic aromatic hydrocarbons(PAHs)are a group of carcinogenic organic pollutants widely existing in the environment.Human body can be exposed through respiratory tract,digestive tract and skin contact.As the PAHs exposure level of the general population is much lower than occupational exposure,and the proportion of lung cancer mortality relative to all-cause mortality is also low,it is difficult to establish the relationship between PAHs exposure level and lung cancer mortality of the general population.In this paper,the exposure assessment with the refined multi-media and multi-channel external comprehensive method and internal exposure assessment with biomarker were used.A certain coking industrial zone in southwestern China around three regions with a gradient distance to the coking industrial zone were selected as sampling regions in this study,that were high exposure region(Region H),middle exposure region(Region M),and low exposure region(Region L).Comprehensive external exposure assessment of PAHs and internal exposure assessment of OH-PAHs in urine were carried out.The results of large-scale lung cancer mortality study and resident questionnaire survey were analyzed.The relationships between population PAHs exposure and lung cancer mortality were discussed.The results could provide scientific basis for PAHs exposure evaluation and lung cancer mortality risk assessment.Through comprehensive external exposure evaluation of PAHs with multiple media and expose ways,it was found that the combined external exposure dose of benzoa(a)pyrene equivalent concentration(BaPeq)of residents in Regions H,M and L were 159 ± 14 ng/(kg·d),7.41 ± 2.76 ng/(kg·d)and 6.13±2.89 ng/(kg·d),respectively.The lifetime cancer risk increment(ILCR)of residents of Region H was one order of magnitude higher than that of the residents in Regions M and L.Inhalation exposure was the main factor of carcinogenic risk of PAHs in Region H(93.4%),indicating that high levels of PAHs pollution in the air could lead to higher concentration of BaPeq and higher carcinogenic risk in the population.Dietary exposure was the main factor of PAHs exposure in non-high environmental pollution areas,and would lead to a higher lifetime carcinogenic risk increment.The total concentrations of the nine OH-PAHs(∑OH-PAH)ranged from 1.48 to 22.6 μg/g crt,with an average of 8.39 ± 4.20 μg/g crt.Spearman one-tail correlation analysis result showed there were significant correlations between 1hydroxynaphthalene,2-hydroxynaphthalene,1-hydroxypyrene,2-hydroxyfluorene and ∑OH-PAH(p<0.01).While the combined exposure dose of OH-PAHs and most monomer OH-PAH had no significant correlation with BaPeq.The results of the study on lung cancer mortality showed that lung cancer was the leading cause of death among all malignancies,which account for 35.3%.The CASMR of lung cancer were 77.94 per 100 000 person-years,33.03 per 100 000 person-years and 14.67 per 100 000 person-years in Regions H,M and L,respectively.The mortality rate of lung cancer in Regions H and L were higher than the national average rate(20.24 per 100 000 person-years).The integrated external exposure doses of BaPeq,dietary exposure dose of BaPeq,inhalation exposure dose of BaPeq,all-cause CASMR,malignant tumor CASMR,and lung cancer CASMR were in the same order.The order from high to low was:Regions H,M and L.While the relationship between urine OH-PAHs exposure biomarkers and lung cancer mortality was not obvious.In conclusion,this paper established the integrated external exposure assessment method,which inclouding much mediums of ambient air,soil,drinking water and dietary,and much exposed ways of inhalation,skin contact and oral intake.It revealed that the BaPeq external integrated exposure dose in the study area has a relationship with lung cancer mortality.It indicated that PAHs exposure had certain health hazard to local residents.The relationship between urine OH-PAHs and lung cancer mortality was relatively weak,suggesting that comprehensive assessment of external exposure to PAHs might be more objective to reflect the risk of lung cancer death for non-professional population.The research results provided a scientific basis for the improvement of PAHs exposure evaluation methods and the analysis of carcinogenic risk.