Analysis On The Heavy Metals And Arsenic Exposure And 8-OHdG And Cystatin C Levels Of Workers In Lead-Zinc Mining And Smelting And Steel Smelting Foundry In Liaoning Province

Objective: Lead-zinc mines are rich in mineral metals such as lead(Pb),cadmium(Cd),copper(Cu),and nickel(Ni),which are widely used in the electronics,mechanical and military industries.The emission of metals caused by mining and smelting in lead-zinc mines polluted the surrounding atmosphere,water,and soil.The pollution is harmful not only to the occupational populations but also to the residents living in the vicinity of the emissions.Environmental and occupational exposure to heavy metals induce several adverse health effects.These heavy metals are not readily degradable in the environment and easily accumulate in human bodies to a very high amount.Although many metals are necessary for human bodies,they can produce adverse effects to human bodies after more than a certain threshold value.Several metals,such as Cd,Ni,and As,are known human carcinogens,and the carcinogenic potential of these heavy metals has been widely studied in humans and experimental animals.Lead-zinc mining and smelting is often accompanied by Pb,Cd,Zn and As release,which can caused adverse health effects to occupational populations.In this study,we conducted a cross-sectional study of an occupational population in a lead-zinc mining and smelting foundry in Liaoning province(China)and simultaneously chose workers from one steel smelting foundry in the same region.The present study aimed at investigating the levels of urinary Pb,Cd,Cu,Ni,and As in the two groups and the influence factors on urinary Pb,Cd,Cu,Ni,and As.In addition,we chose cystatin C as an early renal damage biomarker to compare the degree of kidney damage in the two groups.Finally,we also evaluated oxidative damage(urinary 8-OHdG)in the study populations.Methods: This study was conducted in two foundries with a total of 307 workers: 145 exposed workers from a lead-zinc mining and smelting and 162 controls from a steel smelting foundry,both located in the northeastern part of China.A questionnaire was given to all subjects to obtain information about their age,weight,height,occupational history,disease history,dietary status(including consumption of seafood in the 3 days preceding the start of the study),alcohol consumption,smoking habits,and other lifestyle parameters.Blood pressure was measured after the questionnaire was completed.All subjects with urinary creatinine beyond the range of 0.3-3.0 g/l were excluded according to the World Health Organization criteria for the acceptability of urine samples for biological monitoring.Spot urine samples from all subjects were collected in PVC bottles and kept on ice;urine samples were stored at-20℃,then transported to the China Medical University Laboratory and stored at-80℃ before being analyzed.Determination of urinary Pb,Cd,Cu,and Ni was performed with a graphite furnace atomic absorption spectrophotometer.The urine samples and nitric acid were mixed at a ratio of 100:1(v:v),then digested the urine samples.Standard solutions of Pb,Cd,Cu,and Ni were diluted with normal human urine and used to prepare standard curves.Cold trap hydtide genetation-atomic absorption spectrometry was applied to determine the concentration of iAs,monomethylation arsenic(MMA),dimethylated arsenic(DMA).The total arsnic(TAs)concentration was caculated by summing up the concentrations of iAs,MMA and DMA.The urinary concentrations of 8-OHdG were determined according to the manufacturer’s instructions by using the ELISA kit of Abcam.Urinary cystatin C kits were applied to determine the urinary cystatin C.The levels of urinary creatinine(Cr)determined with jaffe assay were used to adjust the concentrations of Pb,Cd,Cu,Ni,As,8-OHdG and cystatin C in the urine.The concentrations of urinary Pb,Cd,Cu,Ni,8-OHdG and cystatin C were calibrated on the basis of urinary Cr and reported asμg/g Cr.Results: 1.The general state: a total of 307 male workers,including 145 lead-zinc mining and smelting workers and 162 steel smelting workers were recruited in this study.The average age of lead-zinc mining and smelting workers was higher than steel smelting workers.So did the average engagement years.The level of BMI has no difference between the two foundry workers.The smoking rate of both foundry workers were high,lead-zinc mining and smelting workers’ smoking rate was higher than that of steel smelting workers.The seafood intake amount of steel smelting workers was significantly higher than that of lead-zinc mining and smelting workers.The alcohol intake of lead-zinc mining and smelting workers was higher than that of steel smelting workers.2.The levels of urinary heavy metals,iAs and MMA oflead-zinc mining and smelting workers were higher than that of steel smelting workers.3.The workers’ urinary Cd level can be affected by the daily smoking.4.There was no statistical difference between the concentration of 8-OHdG among the two factory workers.Logistic regression analysis of urinary 8-OHdG found that urinary Pb and Cd were statistically significant factors.5.The urinary cystatin C level of lead-zinc mining and smelting workers was higher than that of steel smelting workers.Logistic regression analysis of urinary cystatin C found that age,urinary Cd levels were statistically significant factors.Conclusion: 1.Compared with steel smelting workers,lead-zinc mining and smelting workers had a higher exposure extent of Pb,Cd,Cu,Ni and As.2.The level of urinary8-OHdG may be affected by Pb and Cd.3.The urinary cystatin C level of lead-zinc mining and smelting workers was higher than that of steel smelting workers.Increased age and Cd exposure may be responsible for kidney damage.