A Survey Of Hand-arm Vibration Hazards Of Iron Miners And The Mechanism Of Miners' Capillary Injury

BackgroundIn 1911 Loriga first reported the"white finger"phenomenon in workes who using pneumatic tools, after that we have made a great progress on the mechanism of vibration injury, the dose-effect relationship and hazard of hand-arm transmitted vibration. Miners in china have many opportunities to accept high intensity vibration, and combine with adverse factors such as noise, dust, bad meteorology, and insufficient prevention which can promote hand-arm vibration hazards, the occupational hazards are more complicated and more serious.ObjectiveTo survey the hand-transmitted vibration hazards and other occupational hazards in Cheng Chao iron mine, provide evidence to make occupational hazard evaluation; Invest the workers'health state and influencing factors, understand the feature of vibration hazards; Study the correlation of hand-transmitted vibration and it's hazards, provide epidemiology evidence for risk evaluation of vibration; seek earlier index of capillary injury, provide evidence to verify capillary injury mechanism and to find early diagnostic criteria.Methods1. Occupational hygiene survey of Cheng Chao iron mine.2. Choose male rock drillers as exposure group, and divided to three groups depending on exposure time; choose workers who don't exposure to hand-transmitted vibration as control group.3. Carry on routine examination and special examination to objects, special examination including cool-rewarming test, fingers'microcirculation, hand nerves's function, electrocardiography, X-ray examination of fingers and articulatio carpi, examination of hearing loss.4. Carry out endothelium factors analysis, determin the serum level of endothelin, thromboxane B2,6-KetoPGF1α, angiotensin II, calcitonin gene-related peptide, and nitrogen monoxidum.5. Use spss12.0 statistics software to make t-test,χ2- test, ANOVA.Results 1. Occupational hygiene survey results: The rock drill type that workers use were 76-55, the acceleration of 4 hours energy weighting was 21.4~26.9 m/s2, noise level of working place was 115~118 dB(A), the meteorology of work place in middle November was: temperature 19.6℃, humidity 95%, workers wear ordinary gloves but not wear anti-vibration gloves, no anti-noise and anti-dust prevention, worker have 10 minutes rest within 1 hour work.2. In this survey, there have more incidence of hand numbness, hand pain, headache, insomnia, waist soreness in exposure group than control group (P<0.05), the more exposure time, the high incidence of symptoms.3. Specificity examination: The cold water rewarming test shows that exposure group have higher positive ratio than that of control (P<0.05). Fingers'microcirculation examination shows that exposure group had more abnormality than control (P<0.05). The examination of nerve sensory function result shows that exposure had more abnormality than control (P<0.05). X-ray examination of phalanges and articulatio carpi found that there were more widen basilar part of phalanges and hyperosteogeny in exposure group than control (P<0.05). Hearing loss examination shows that hearing loss were more obviously in exposure group than control (P<0.05).4. Serology result: The serum level of endothelin, thromboxane B2,angiotensin II in exposure group were more higher than that of control, The serum level of 6-KetoPGF1α, calcitonin gene-related peptide, nitrogen monoxidum in exposure group were more lower than that of control, and the more exposure time the more obvious changes.Conclusions1. Workers in Cheng Chao iron mine had a high intensity exposure to hand-transmitted vibration, the magnitude is 4~5 times higher than nation hygienic standard, combine with noise and bad meteorology, and insufficient self protective which can advance vibration hazards.2. Long time exposure to hand-transmitted vibration may injury workers'health, appear dysfunction of cardiovascular system, nervous system, skeletal system, auditory system.3. Long time exposure to hand-transmitted vibration can change workers'serum concentration of endothelium factors, shows that the increase of ET, TXB2, AngⅡ,and the decrease of NO, CGRP, 6-Keto-PGF1α, this changes probably is the mechanism of capillary injury, is still need further study to identify whether it can make as a diagnostic criteria.4. There were dose-effect relationship between hand-transmitted vibration and hazards, with the increased exposure time, the workers appear more symptoms, and endothelium factors change more obviously.5. According to the feature of iron mine vibration, improve work condition, reduce work time, enhance health surveillance, equip with personal protective articles, can reduce the harm of vibration.