Relationship Between Vibration Exposure Level And Damage Effect Of Hand-held Workpieces Grinding Workers In A Guangdong Enterprise

Objectives:This study aims at monitoring the hand-transmitted vibration(HAV)exposure level of workers exposed to vibration,determining the HAV exposure level and hazard level of different grinding positions,assessing the HAV cumulative exposure level hand-held workpiece grinding workers exposed to explore the relationship between HAV exposure characteristic and health effects,HAV exposure level and health effects of hand-held workpiece grinding and provide scientific basis for further prevention and control of HAV hazards.Methods:All grinding workers in a large sport equipment factory manufacturing golf club heads in Guangdong Province were involved as target population,among which 162 grinding workers were recruited by random sampling.This study conducted occupational epidemiological surveys(including workplace survey,subject survey,and HAV level measurement),assessed the HAV exposure level and identify the health evaluation(peripheral nerve injury assessment and peripheral vascular injury assessment).Results:1.HAV exposure characteristics of grinding positionThe average median(quartile)of the 8-hour energy equivalent total vibration value A(8)of 66 grinding positions was 4.42(3.20),among which 44 positions exceeded the occupational exposure limit of 3.5m/s2(the over-standard rate was 66.7%).The hand-transmitted vibration hazard classification is carried out for the grinding positions,including 0 hazardous position at level 0,21 hazardous positions at level I(31.8%of total grinding positions),33 level II hazardous positions(accounting for 66.0%),and 12 level III hazardous positions(accounting for 18.2%).The golf club heads were divided into rough grinding and fine grinding according to grinding style,and their A(8)value X±SD were 5.51±2.50m/s2 and 4.65±1.97m/s2,respectively,and the results showed that the mean values of these grinding style A(8)were statistically different(P<0.05).The golf club heads were divided into solid stainless steel club head,hollow stainless steel club head and hollow titanium alloy club head according to materials and type of club head,and their A(8)value X±SD were 3.16±0.84m/s2,4.94±2.03 m/s2 and 7.58d±1.97m/s2,respectively.These results showed that the mean values of these club head A(8)were statistically different(P<0.05).In the rough grinding operation,the mean value of A(8)between hollow titanium alloy club head,solid stainless steel club head and hollow stainless steel club head was statistically different(P<0.05),while there was no significant difference in the mean value of A(8)between solid stainless steel club head and hollow stainless steel club head(P>0.05).In fine grinding operation,the mean value of A(8)between hollow titanium alloy club head,solid stainless steel club head and hollow stainless steel club head was statistically different(P<0.05),and there was no significant difference in the mean value of A(8)between hollow titanium alloy club head and hollow stainless steel club head(P>0.05).The results of spectrum analysis showed that the characteristics of the three types of club head frequency curves were basically the same,and the trend of different axial directions of same type of club heads was basically the same.The main frequency range was mainly in the range of 200-1600 Hz,and the spectral components were mainly high frequency vibration.2.Grinding workers’ cumulative exposure levels and health statusThe 8-hour equivalent energy-weighted acceleration value A(8)of grinding workers’ daily vibration exposure ranged from 1.09 to 15.2 m/s2.The X±SD of cumulative vibration exposure level(CVEL)of grinding workers was 11.43± 1.04.The quartile spacing of CVEL of the grinding workers was divided into low-exposure group(CVEL<10.79),middle-exposure group(CVEL 10.79-11.50)and high-exposure group(CVEL>11.50).Among the 162 grinding workers,there were 130(80.2%)workers who had peripheral nerve injury,76(46.9%)workers who had peripheral vascular injuries,and 76(46.9%)workers who had peripheral vascular injury.The numbers of workers who complained symptoms such as finger numbness,finger pain,palm sweating,finger deformation,muscle atrophy,hand tremor,hand stiffness,and hand swelling were 127,69,59,69,7,54,65,62,accounting for 78.4%,42.6%,36.4%,42.6%,4.3%,33.3%,40.1%,and 38.3,respectively.There were significant differences in peripheral nerve injury between different cumulative exposure groups(P<0.05),and there was a statistical difference between the low-exposure group and the middle-exposure group and the high-exposure group(P<0.05).There were significant differences in peripheral vascular injury between different cumulative exposure groups(P<0.05),and there was a statistically significant difference between the low-exposure group and the high-exposure group(P<0.05).3.Dose-response relationship between CVEL and peripheral nerve injuryThe results of binary logistic regression model showed that age,smoking habits and drinking habits were less correlated with peripheral nerve injury in the workers(P>0.05);the values of OR in the CVEL exposure group compared with the CVEL low-exposure group(95%CI)was 4.559(1.404,14.80),the difference was statistically significant(P<0.05),while compared with the CVEL high-exposure group the CVEL low-exposure group,the OR value(95%CI)was 4.387(1.335,14.42),and the difference was statistically significant(P<0.05).4.Dose-response relationship between the CVEL and peripheral vascular injuryThe results of binary logistic regression model showed that age,smoking habits and drinking habits were less correlated with peripheral blood vessel damage in the workers(P>0.05);the values of OR in the CVEL exposure group compared with the CVEL low-exposure group(95%CI)was 1.859(1.606,9.708),the difference was not statistically significant(P>0.05),while compared with the CVEL high-exposure group the CVEL low-exposure group,the OR value(95%Cl)was 3.949(1.606,9.708),and the difference was statistically significant(P<0.05).Conclusions:1.The hand-held workpieces grinding positions of the sports factories have high HAV occupational exposure levels and high occupational health risks,among which the positions of grinding hollow titanium alloy golf club head and grinding hollow stainless steel are critical control point.2.There were effect relationships between the CVEL high-exposure group and the middle-exposure group and the low-exposure group’s peripheral nerve injury in the hand-held workpieces grinding workers of this sports factory,and there were effect relationships between the CVEL high-exposure group and the low-exposure group’s peripheral blood vessel damage.