Study On The Exposure Characteristics And Health Risk Of Polycyclic Aromatic Hydrocarbons In Coal Tar Pitch Occupational Exposure Population

【Objective】1.To understand the exposure characteristics of polycyclic aromatic hydrocar-bons(PAHs)in the coal tar pitch occupational exposure population.2.To evaluate the occupational health risks of coal tar pitch occupational exposure workers;3.To explore contact biomarkers in the urine of polycyclic aromatic hydrocar-bons(PAHs)in the coal tar pitch occupational exposure population.【Methods】1.The occupational hygienic investigation of coal tar pitch contact enterprise was carried out to understand the conditions of its technology and distribution,and then the detection scheme was formulated.2.The concentration of PAHs in the air of the workplace and the concentration of PAHs metabolites in the urine of the workers were detected by the test method.At the same time,two communities were selected to detect the concentration of PAHs in the air.3.The comprehensive analysis method was used to study the exposure characteristics and the contact biomarkers of polycyclic aromatic hydrocarbons in coal tar pitch contact population.4.Cumulative toxic equivalent dose,carcinogenic risk factor and life expectancy loss were used to assess occupational health risk of occupational exposure workers.5.IBM SPSS 22 was used to analyze the data.【Results】1.The results of field investigationThrough the investigation of production process,We know that there were four workshops and fifteen posts in the workplace which contact with coal tar pitch,such as molding workshop and batching operator,etc.2.The test results air samples.The concentrations of polycyclic aromatic hydrocarbons(PAHs)in the two communities and the coal tar pitch operation sites showed no significant difference(P<0.05),but significant differences were observed in the concentrations of benzo[k]fluoranthene and some other PAHs between remote industrial area and near industrial area(P<0.05).With respect to carcinogenic equivalent concentrations of PAHs,the equivalent concentrations of acenaphthylene(ACP)and other nine PAHs were as follows in reducing sequence:molding shop,calcination shop,and roasting shop,which showed significant differences in the three main contaminated workshops(P<0.05).The equivalent concentration of the near industrial community was larger than that of the remote industrial community.In the equivalent concentration of working-types,the overall concentrations of PAHs exposed in the molding shop and the calcination shop were the highest,in which the concentration of TEQ in operator,a working-type with the highest exposure,in vibro-stands was 1931.45 ng/m~3.3.Exposure characteristics of PAHs.The release of PAHs mainly come from traffic pollution and heat source combustion in the remote industrial community,and from traffic pollution,heat source combustion and emission of industrial exhaust in the near industrial community.In the workplace,PAHs with relatively high concentrations were mainly 4-ring PAHs in the molding workshop,4-5 ring PAHs in the calcination shop,2-4 ring PAHs in the roasting workshop,and 2-ring PAHs in the laboratory.4.Occupational health risk assessment.With the increase of average daily exposure concentration,the incidence of life-time excess risk limits of workers will enhance.The exposure dose of work posts in the industry was 17~1342 times more than that of two communities.The excess carcinogenic risk limit of each working-type in the industry was 10-100 times higher than the maximum acceptable value.Increasing of daily average exposure concentration and life-long excessive risk limit in workers induced higher loss of life expectancy in working-types(ranging from 18.30 hours to 1033.95 hours),which was37.5-1459 times higher than that of normal adults in the same area.5.Detection results of metabolites in PAHs.The workers had a similar tendency in OH-PAHs concentration changes of urinary samples compared with workers exposed to PAHs concentrations in working environment after confounding factors exclusion.What’s more,concentrations of1-+2-hydroxy naphthalene,2-hydroxyl phenanthrene and 1-hydroxypyrene were positively correlated with total concentration of PAHs(P<0.05),while 3-hydroxyl phenanthrene and 4-hydroxyl phenanthrene had no correlation with total concentration of PAHs,and there was a positive correlation between every two OH-PAHs(P<0.05).【Conclusions】1.The coal tar pitch volatiles and PAHs had a higher concentrations in the CTP workplace,which have exceeded occupational maximum limits generally.And the types of PAHs differ from different occupational workshops,such as phenanthrene in molding shop,acenaphthylene in the calcination shop,pyrene in the roasting shop,and fluoranthene in the laboratory.In conclusion,PAHs is the main strongly carcinogenic substance in workplaces with coal tar pitch using.2.Two-thirds of occupational workers,threatened by higher occupational carcinogenic risks,have 37.5-1459 times higher loss of life expectancy than the normal adults in the same area.3.There are positive correlations between PAHs and 1-+2-hydroxynaphthalene,2-hydroxyphenanthrene and 1-hydroxyanthraquinone,which can be used as contact biomarkers of PAHs in urine of CTP occupational workers.