Study On The Pollution Characteristics Of Polycyclic Aromatic Hydrocarbons And Organochlorine Pesticides In Vegetables Sold In Xuzhou And The Risk Of Population Exposure

Polycyclic aromatic hydrocarbons(PAHs)and organochlorine pesticides(OCPs)are two types of typical persistent organic pollutants(POPs),which are mainly derived from incomplete combustion or pyrolysis of organic matter.OCPs have been widely used in agricultural production,with DDTs and HCHs being the most representative organochlorine insecticides.PAHs,DDTs and HCHs are widely found in environmental media,which are carcinogenic,teratogenic and mutagenic.They can enter the human body through diet,breathing and skin,posing a threat to the health of the population.From this point of view,it has become one of the important research topics to analyze the PAHs,DDTs and HCHs pollution in the environment.Xuzhou,a typical central plain city in China,has a strong economic reliance on petrochemical,steel,and heavy industries.However,when it comes to the PAHs,DDTs and HCHs in vegetables,no practical efforts have been made in Xuzhou.In this study,we research on the PAHs?DDTs and HCHs in vegetables in Xuzhou.Several kinds of vegetables(leaf vegetables,rhizome vegetables and fruits vegetables),which are widely consumed by local residents,were sampled.Concentrations of PAHs,DDTs and HCHs in vegetables were determined by GC-MS,and the pollution sources,ingestion and inhalation exposure,and the induced health risk of DDTs and HCHs were further analyzed in this study.The total concentration of 16 PAHs in 14 kinds of vegetables sold in Xuzhou ranged from 29.77 to 58.57 ng/g,with an average concentration of 42.93 ng/g.The concentrations for different categories of vegetables in decreasing order was:leafy vegetables,rhizome vegetables,and fruit vegetables.The BaP concentration is ranging from 0.13 to 0.28 ng/g,and the concentration of BaP is much lower than the limit of BaP in food in China.The five compounds that contribute the most to ∑PAHs in vegetables are NAP,PHE,FLO,FLA and PYR.Residual concentrations of ∑10OCPs in different kinds of vegetables:leafy vegetables rhizome vegetables>fruits and vegetables.The total concentration of DDTs in vegetables was between 0.01 and 0.45 ng/g,with a mean of 0.28 ng/g,and the total concentration of HCHs was between 0.04 and 1.10 ng/g,with a mean of 0.40 ng/g.The contribution of DDTs compounds in decreasing order was is:o,p’-DDT>p,p’-DDD>p,p’-DDT>o,p’-DDD>p,p’-DDE>o,p’-DDE,while HCHs compound monomer contribution to ∑HCHs:β-HCH>α-HCH>δ-HCH>γ-HCH.The pollution levels of PAHs,DDTs and HCHs in vegetables sold in Xuzhou are at a low level compared with other cities in China,but still higher than those in developed countries.According to the ratio of ANT/(ANT+PHE),BaA/(BaA+CHR),FLA/(FLA+PYR),IcdP/(IcdP+BghiP),BaP/BghiP and FLO/(FLO+PYR),the PAHs source analysis was carried out.It was found that the main source of from oil,coal combustion and gasoline diesel exhaust emissions.The OCPs source analysis found that the WDDD/WDDT value was less than 1,indicating that DDTs were derived from the input of new pollution sources,and Wβ/(α+γ)-HCH were less than 0.5,indicating that HCHs in vegetables mainly originated from historical residues.The dietary exposure of PAH4 and PAH 16 for different population groups in Xuzhou in decreasing order was:adult>seniors>adolescents>children,while the order of DDTs exposure in each group was:children>adolescents>adults>seniors,the order of HCHs exposure is:children>adolescents>Seniors>Adults,and in terms of gender,the exposure of men was always higher than that of women.What’s more,the exposure of DDTs was higher than than of the HCHs.The lifetime carcinogenic risk of PAHs produced by ingestion exposure showed that the ILCR values of the eight groups were lower than the acceptable risk level(10-6),indicating no potential cancer risk at the current dietary exposure level.The median values of MOE for both PAH4 and PAH16 exposure were greater than 10 000 for all population groups in Xuzhou,indicating that there is no additional risk associated with the consumption of vegetables with the current ingestion rate.The residual carcinogenic risk of DDTs and HCHs in vegetables is between 10-6 and 10-4,indicating potential cancer risk.The risk of HCHs is always higher than the risk of DDTs.The non-cancer risk of DDTs and HCHs in vegetables for different age and gender groups in Xuzhou were all less than 1,indicating there was no non-cancer risk for local residents.For cancer risk,The major contributors of compounds for DDTs induced cancer risk were o,p’-DDD(46.60%～48.81%),δ-HCH contributed the highest total carcinogenic risk of HCHs,with an average contribution rate of 59.32%.For non-oncogenic risk,p,p’-DDE is the most important isomer of non-cancer risk produced by DDTs,while δ-HCH is the most important contributor to the non-carcinogenic risk of HCHs.The total cancer risk of PAHs,DDTs and HCHs is between 10-6 and 10-4,indicating that there is potential cancer risk.