| Polycyclic aromatic hydrocarbons（PAHs）are among the earliest detected and most abundant carcinogenic substances,posing severe toxicity to living organisms.PAHs are widely present in various environmental media and can accumulate through the food chain.For non-smokers with non-occupational exposure,dietary intake is the primary pathway of PAHs exposure.Lanzhou is rich in mineral resources,with many heavy industries such as metal smelting,coal mining,and petroleum refining,leading to increasingly severe PAHs contamination.Therefore,it is crucial to conduct dietary PAHs exposure and health risks assessment to explore the potential association between dietary PAHs exposure level and health indicators for implementing precise prevention and control measures and improving human health outcomes.This study selected Chengguan District and Yuzhong County in Lanzhou as representative urban and rural areas,respectively.A human exposure behavior survey and dietary were conducted to obtain exposure parameters and individual information.Daily dietary samples were collected using the duplicate-meal method in tracking and monitoring of PAHs exposure,and the contents of 16 priority PAHs were measured using Gas Chromatography-Mass Spectrometry（GC/MS）.Health examinations were also conducted for rural populations.By analyzing the relevant data,this study characterizes dietary PAHs concentrations of Lanzhou residents,and conducts exposure and health risk assessments.Furthermore,it explores the potential association between dietary PAHs exposure levels and health indicators.The main findings are as follows:（1）The occurrence levels of resident dietary PAHs in Lanzhou did not exceed the standard limits,and the pollution characteristics varied in terms of urban-rural areas,seasons,and food types.The concentration of PAH16 in the dietary samples of Lanzhou residents was12.79±0.39 ng/g,which was relatively low in China.The concentration of PAH4（0.98±0.06 ng/g）did not exceed the European Union standard（10 ng/g）.The differences in the occurrence levels mainly were:rural area（14.37±0.56 ng/g）was higher than urban area（11.79±0.53 ng/g）,heating period（14.54±0.65 ng/g）was higher than non-heating period（11.91±0.44 ng/g）,side dishes（18.23±0.56）ng/g)was higher than that of staple food（8.83±0.43 ng/g）,which were both higher than raw ingredients（2.31±0.22 ng/g）.The distribution of monomers and cycloidal number was mainly composed of 2～3 cycloidal compounds represented by Nap and Phe（76.4%）.The proportion of 4～6 cyclic compounds in rural areas（24.5%）was higher than that in urban areas（22.1%）,and the proportion of complementary food（24.8%）was higher than that of staple food（21.1%）.（2）The dietary PAHs exposure levels of Lanzhou residents showed urban-rural and seasonal differences.The daily dietary intakes（DDI）of PAH16 was 2.67×10-4 mg/（kg·d）,exhibiting a trend of higher levels in rural areas than in urban areas,higher during the heating period than the non-heating period,and higher in males than in females.In the non-heating period,the DDI level was highest for those aged 45～59 years.During the non-heating period,the DDI levels showed a pattern of 45～59 years old>18～44 years old,which was related to the dietary structure of different age groups,while this pattern may not exist during the heating season due to the influence of heating behaviors.The overall Ba P equivalent average daily exposure（ED）level was 7.34 ng/（kg·d）,and the same-sex population showed higher levels in rural areas than in urban areas and higher levels during the heating period than the non-heating period.Seasonal differences were more pronounced during the heating period in rural areas and during the non-heating period in urban areas,with no consistent patterns across different genders and age groups.（3）The health risks of dietary PAHs exposure among Lanzhou residents were within acceptable limits.For all classified population groups,the MOEs values of Ba P,PAH4,and PAH8levels were higher than 104,indicating that the impact of dietary PAHs exposure for the selected participants were still within controllable limits.The risk level in urban areas was slightly lower than rural areas,and the risk level during the heating season was slightly higher than the non-heating season.The increased lifetime cancer risk（ILCR）values for all population groups ranged from 10-6 to 10-4,suggesting that the carcinogenic risks from dietary PAHs exposure were within the acceptable range.The carcinogenic risk was lower in urban areas than in rural areas,and higher during the heating period than the non-heating period.Furthermore,individuals aged 45～59 in urban areas and those aged 18～44 in rural areas were found to have the highest health risks.Results of uncertainty analysis using Monte Carlo simulation showed that the health risk of the rural population may be underestimated,with higher risks among this population compared to urban dwellers.Sensitivity analysis revealed that PAHs concentration（C or TEQ）contributed the most to health risk,but the dietary intake（IR）and C（or TEQ）contributed equally to health risk among rural women.（4）There was a potential correlation between dietary PAHs exposure levels and health indicators,but it was not the primary influencing factor.There was no significant correlation between PAH16 and all health indicators.Results from the generalized linear model showed that the main effect of PAH16 had a significant negative impact on ALP,Lym,HGB and PDW,and a significant positive effect on TBIL,IBIL,p H and Eos.The interaction effect containing PAH16 did not have a uniform rule on health indicators,mainly manifesting as a positive effect on ALT,ALP,TBIL and IBIL,significant positive effect on UREA,UA and UREA/C of renal function,and significant positive effect on Eos and Mon of blood cell indicators.While there is a certain correlation between dietary PAHs exposure level and human health indicators,there is no significant correlation between the two.Low-dose PAHs exposure in the general population is not a significant factor causing bodily injury.In conclusion,the occurrence levels of dietary PAHs for Lanzhou residents did not exceed the standard limit.However,pollutions were relatively more severe in rural areas,during heating seasons,and for supplementary food.Additionally,there were urban-rural,seasonal,and gender differences in individual exposure levels,with males generally having higher levels than females.The health risks from dietary PAHs exposure in the Lanzhou were within acceptable limits,and dietary PAHs exposure had a certain degree of impact on health indicators but were not a significant factor causing bodily injury in the general population.Currently,the dietary PAHs exposure and associated health risks for Lanzhou residents were under control,but the prevention and control of dietary PAHs pollution should be given attention,particularly for key populations. |
