| Among the atmospheric particulate matter,fine particulate particles(PM2.5)with a diameter of≤2.5μm can cause lung disease,cardiovascular disease,and metabolic disease.In addition to PM2.5 itself,the PM2.5-bound pollutants cannot be ignored to human health.Polycyclic aromatic hydrocarbons（PAHs）and their derivatives in PM2.5,such as nitrated PAHs（NPAHs）and oxygenated PAHs（OPAHs）,have always been concerned because of the huge threat to human health.OPAHs are very toxic,some studies have fully proved that OPAHs have stronger endocrine disrupting effects,mutagenicity and DNA damage ability than parent PAHs.In China,the research on OPAHs in PM2.5 mainly focuses on the temporal and spatial distribution,emission characteristic spectrum and source analysis,while the research on the toxic effects of OPAHs is limited.What is notable is that aromatic hydrocarbon compounds mainly cause effects by binding to aromatic hydrocarbon receptors（Ah R）.When Ah R is activated by high-affinity aromatic hydrocarbon ligands,it can induce serious biochemical and toxic effects.Based on the above background,this study sampled PM2.5 in different areas of Nanjing city,and identified 10 OPAHs with a gas chromatography mass spectrometer.Then the simulated lung fluid was used in testing the bioavailability of OPAHs in PM2.5.Finally,we used human hepatoblastoma Hep G2 cells stably transfected with p G14.43 plasmid to discuss the binding effect of OPAHs and Ah R.The research content and results are as follows:（1）PM2.5 samples were collected in three areas of Nanjing city（Nanjing Chemical Industrial Park（CIP）,Nanjing Xuanwu Lake Tunnel（XLT）and Nanjing Gucheng Lake Ecological Observation Station（GLEOS））.The study analyzed 10 different PM2.5-bound OPAHs by gas chromatography mass spectrometer.The results showed that the average concentration of OPAHs in PM2.5 were:BEZO>ATQ>2-MAQ>1,2-ACQ>9-FL>BAQ>1-NLD>1,8-NAA>1-INDA>1,4-NQ.Among them,BEZO,ATQ and 2-MAQ had the highest concentrations,with average concentrations of 0.612 ng/m3,0.458 ng/m3 and 0.458ng/m3,respectively.The total concentration of OPAHs in PM2.5 in XLT was higher than the total concentrations of OPAHs in PM2.5 in the other two areas.（2）The bioavailability of OPAHs loaded on PM2.5 in simulated lung fluid was studied.The order of OPAHs bioavailability was as follows:ATQ>1,4-NQ>1-NLD>1,2-ACQ>9-FL>1-INDA>1,8-NAA>2-MAQ>BAQ>BEZO.The range of OPAHs bioavailability was:61.25±9.715%-99.20±3.363%.The result reflected that the bioavailability of OPAHs was related to the Log Kow and the number of benzene rings.（3）The study used human hepatocellular Hep G2 cells stably transfected with p G14.43plasmid,and the luciferase reporter gene assays,to explore the inducing effect of OPAHs on human Ah R.The results showed that BEZO and BAQ had high Ah R-mediated potency,while the other 7 OPAHs had low high Ah R-mediated potency.Exposure time had a significant effect on the binding effect of OPAHs and Ah R.OPAHs exposure for 6 h can induce more Ah R-mediated activity than exposure for 24 h.The study took the binding effect of benzopyrene and Ah R as a reference,then obtained the human Ah R-inducing relative potencies（REPs）of each OPAHs,and calculated the carcinogenic risk of PM2.5-bound OPAHs.The results showed that the three OPAHs with the highest carcinogenic risk were BEZO,BAQ and ATQ.The ILCR values of CIP,XLT and GLEOS were 1.024×10-7,1.351×10-7 and 5.368×10-8,respectively.The cancer risk in these three areas was low risk. |
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