Polycyclic Aromatic Hydrocarbon Exposure And DNA Oxidative Damage Of Workers In Workshops Of A Petrochemical Group

Polycyclic aromatic hydrocarbons（PAHs）are a class of persistent organic pollutants in the environment,which have adverse health consequences on the human reproductive,endocrine,respiratory and nervous systems.Inhalation,dietary and dermal contact are mainly pathways for PAHs enter to human body.A large number of biomonitoring data have demonstrated that general and occupational populations are extensively exposed to PAHs and the exposure has a significant dose-response relationship with oxidative stress.The petrochemical industry is one of the key industries to promote the high-quality development of the Chinese economy.High-quality development of this industry is a great significance to establish the manufacturing power.The petrochemical industry has promoted the development of economy,while PAHs produced by the industry become a threat to environment and humans.However,the research on the petrochemical industry mainly focuses on the environmental media such as water environment,soil and ambient air,and the data using urinary polycyclic aromatic hydrocarbon metabolites（OH-PAHs）as biomarkers to evaluate PAH internal exposure of workers in petrochemical plants are limited.Therefore,we selected the workers from a petrochemical group in Northeast China as the research object to explore the relationship between PAH exposure,other potentially hazardous substances as well as noise and8-hydroxy-2’-deoxyguanosine（8-OHd G）,a biomarker of DNA oxidative damage.In May 2019,a total of 546 volunteers were recruited from a petrochemical plant.Urine samples and questionnaires were collected.Urinary OH-PAHs and 8-OHd G were measured.Combined with the information from the questionnaires,the effects of age,gender,work history,as well as job titles on levels of PAH exposure and DNA oxidative damages were investigated.And the effects of noise and exposure to other potential chemicals on levels of DNA oxidative damages were also investigated.The concentrations of∑₉OH-PAH in all workers were 0.25-175μg/g Cre with a median of4.41μg/g Cre.Except for 4-hydroxyphenanthrene（83%）and 6-hydroxychrysene（40%）,the detection rates of the other OH-PAHs were>94%.Moreover,metabolites of naphthalene were the predominant compounds,accounting for 64%of total amount.The concentration of∑₉OH-PAH showed differences among different jobs titles and the mean values of∑₉OH-PAH varied by job titles in the decreasing order:Recycling workers（13.7μg/g Cre）>Intermediate manufacturing workers（8.71μg/g Cre）and Spinning workers（8.39μg/g/g）g Cre)>Raw material manufacturing workers（7.83μg/g Cre）and Workshop supervisors（7.36μg/g Cre）>Technology and maintenance workers（6.16μg/g Cre）>Agency administration（5.12μg/g Cre）.The median concentration of∑₉OH-PAH in male workers（4.70μg/g Cre）was significantly higher than that in female workers（3.67μg/g Cre）.In addition,although no differences were observed in concentrations of OH-PAHs for workers of different gender or ages,higher levels of OH-PAHs were observed in the older workers（40-60 years old）,and concentrations of metabolites of naphthalene,fluorine and pyrene as well as∑₉OH-PAH showed a trend of increasing gradually with the increase of working history.Moreover,there was a dose-response relationship between levels of 8-OHd G and∑₉OH-PAHs（r=0.28,p<0.01）.The concentrations of 8-OHd G in all workers ranged from 0.50 to 90.7μg/g Cre（0.15 to83.0μg/L）,with a median value of 6.17μg/g Cre（8.18μg/L）.No difference was observed in concentrations of 8-OHd G for workers of different gender,ages or work history,but job titles.Besides,no connection was found between noise pollution and levels of 8-OHd G in present study,and there was no difference for concentration of 8-OHd G between the groups of noise exposure（median:6.13μg/g Cre）and no-noise exposure（median:6.28μg/g Cre）（p>0.05）.In addition to PAHs,exposure other potentially hazardous chemicals in the working environment can also cause oxidative stress in the human body.Taking 8-OHd G concentrations in the group of low-toxicity as reference,the adjusted odds ratios（OR）of participants for urinary 8-OHd G were 1.25（95%CI:0.67-2.32）,3.22（95%CI:1.63-6.33）,3.47（95%CI:1.64-7.33）,1.07（95%CI:0.60-1.89）and 1.71（95%CI:0.80-3.70）for workers in EAS（exposure to all toxicants）,ETT（exposure to three toxic substances）,EHCN（exposure to hydrogen cyanide and nitrile）,EA（exposure to acrylonitrile）and EHC（exposure to hydrogen cyanide）,respectively.Especially in the workers of ETT and EHCN showed higher OR values（3.22 and 3.47 respectively）,indicating that exposure to potentially toxic substances may elevate the level of urinary 8-OHd G.Furthermore,workers simultaneously exposed to low-toxicity pollutants and higher levels of∑₉OH-PAH had significantly higher levels of urinary 8-OHd G,and the value of OR was 29.8times higher than those in the corresponding subgroups.Our results suggested that exposure to PAHs or co-exposure to PAHs and potential toxics in the petrochemical plant may cause DNA damage.We call for more researches on the associations among noise,chemical pollution and oxidative stress to workers in the real working environment.