Associations Of Benzene,arsenic And Lead Exposure With Health Indices Among Coking Plant Employee

Objective:To explore the associations of occupational benzene,arsenic and lead exposure with pulmonary function,blood pressure,and blood biochemical indices,and to find out the potential health impacts of benzene,arsenic and lead exposure among coking plant employee,and provide evidence for potential protective measures.Methods:We investigated 617 workers from a coke plant in Taiyuan,Shanxi,P.R,China,categorized into benzene-exposed group and controls based on their working sites in workplace and urinary phenol concentrations.We also categorized participants into low,middle and high groups according to their arsenic and lead levels in urine,respectively.Post-shift urine samples were collected in the morning and were measured the phenol concentrations using gas chromatography equipped with a hydrogen flame ionization detector,determined arsenic and lead concentrations using atomic fluorescence spectrophotometer.And pulmonary function and blood pressure were measured by professional medical staffs.Fasting venous blood was drawn in the morning and was used to detect the levels of hematologic parameters and biochemical indices,including white blood cells(WBC),red blood cells(RBC),hemoglobin(HGB),platelets(PLT),fasting blood glucose(FPG),total cholesterol(TC),triglyceride(TG),high-density lipoprotein(HDL),low-density lipoprotein(LDL),aspartate aminotransferase(AST),alanine aminotransferase(ALT),serum uric acid(SUA),serum creatinine(SCR)and urea(URE).Covariance analysis and multiple linear regressions were used to test the associations of urinary phenol,arsenic and lead concentrations with various levels of health indices in coke oven workers.Results:The subjects were predominantly males(n=576,93%),with an average age of(44.4±7.9)years and an average working length of(25.1±8.9)years.The results of environmental monitoring show that the time-weighted average(TWA)and short-term exposure limits(STEL)of benzene and benzene homolog in the air of the coke plant were lower than occupational exposure limits specified in national standard.And the workers were categorized into benzene-exposed group and controls(unexposed group)based on their workplace.The median(interquartile interval)concentration of urinary phenol was 6.00(0.03,31.00)μg/mL in the benzene-exposed group,which was significantly higher than that in the controls(P<0.05).The results of health surveillance show that,compared with the control group,the levels of FVC and serum LDL were significantly decreased in the benzene exposed group,while the serum creatinine and uric acid concentrations were increased(P<0.10).Covariance analysis indicated that the levels of FVC and serum LDL in the exposed group were significantly reduced compared with the control group(P<0.05),and the serum ALT level was also decresed(P<0.10).After adjusting for covariates,multiple linear regression showed that,an increase of each natural logarithm(Ln)transformed urinary phenol concentration was significantly associated with increases in serum TC concentrations[0.10(95%CI:0.01,0.19)mmol/L].An increase of each Ln-transformed accumulated benzene exposure levels was significantly associated with an increase in serum TC levels[0.09(95%CI:0.01,0.17)mmol/L]and TG levels[0.14(95%CI:0.01,0.27)mmol/L].The median concentration(Inter-quartile range)of urinary arsenic among coke oven workers was 3.35μg/g Cr(1.88~4.65μg/g Cr).We categorized subjects into 3 subgroups according to the tertiles of urinary phenol concentrations:1st tertile(<2.32μg/g Cr),2nd tertile(2.32~4.26μg/g Cr),and 3rd tertile(≥4.26μg/g Cr).The levels of SBP,WBC counts,serum AST and ALT in the 3rd tertile were significantly lower than that in the 1st and 2nd tertiles.Multiple linear regression showed that,an increase of each natural logarithm(Ln)transformed urinary arsenic concentration was significantly associated with decreases in SBP levels[1.46(95%CI:-2.78,-0.14)mmHg](P<0.05),WBC counts[0.13(95%CI:-0.28,0.02)×10~9/L],PLT counts[4.40(95%CI:-9.26,0.46)×10~9/L],and serum SUA concentrations[6.92(95%CI:-10.95,0.12)μmol/L](P<0.10).With an increase of one unit of natural logarithm(Ln)transformed arsenic accumulation,WBC counts were marginally lower by0.12-×10~9/L(95%CI:-0.24,-0.01),and serum SUA concentration was marginally lower by9.01-μmol/L(95%CI:-14.44,-3.58)(P<0.05).The median(Inter-quartile range)concentration of urinary lead among coke oven workers was 0.74μg/g Cr(0.29~1.82μg/g Cr).The subjects were categorized into 3 groups according to the tertiles of urinary lead concentrations:lower tertile(<0.41μg/g Cr),middle tertile(0.41~1.15μg/g Cr),and higher tertile(≥1.15μg/g Cr).Compared to the lower tertile,the DBP level in the middle tertile was significantly decreased,while the serum LDL concentration was significantly increased.And the SBP level in the higher tertile was significantly lower than that in the lower tertile.Multiple linear regression showed that,an increase in natural logarithm(Ln)transformed urinary lead concentration was significantly associated with decreases in serum SUA level[-5.56(95%CI:-9.87,-1.24)],and was significantly associated with increases in serum concentrations of TC[0.02(95%CI:0.00,0.10)mmol/L]and LDL[0.05(95%CI:0.01,0.08)mmol/L].Moreover,our study found that benzene and arsenic co-exposure synergistically increased the concentrations of serum TC(P<0.10).Arsenic exposure showed a potentiation joint action on the increase of serum creatinine levels induced by benzene,while lead exposure enhanced the reduction of serum creatinine levels(P<0.05).And benzene,arsenic and lead co-exposure synergistically increased the SBP level(P<0.05).Conclusion:Our findings indicate that benzene,arsenic and lead exposure are possibly related to the variation of purine and total cholesterol metabolism,blood pressure,and hematologic parameters in coke oven workers.Benzene and arsenic co-exposure synergistically increased the concentrations of serum TC,and arsenic exposure showed a potentiation joint action on the increase of serum creatinine levels induced by benzene,while lead exposure enhanced the reduction of serum creatinine levels.And benzene,arsenic and lead co-exposure synergistically increased the SBP level...