| Mercury thermometer is one of the thermometers, with mercury column showing temperature, made of glass and mercury. With the widespread use of mercury thermometer in the medical field and the ordinary family, its adverse effects to human and environment are concerned by the governments and peoples. Considered of the hazards of mercury in the mercury thermometer, many countries have banned the production and use of mercury thermometers. At present, China does not prohibit the use of mercury thermometers and mercury thermometers manufacturing companies throughout the country, which is seriously harmful to the environment and peoples, especially mercury thermometers production workers.Mercury is a unique heavy metal presented in a liquid form. In the environments, mercury is found as a metallic or elemental form, inorganic compounds or organic compounds. Mercury is a non-essential element of the human body. Minute quantity is harmful to the body. All forms of mercury can cause multi-system damage, especially metallic mercury and methylmercury. Mercury is highly toxic to environment and human, including neurotoxicity, nephrotoxicity, hepatotoxicity, immunotoxicity, reproductive toxicity and genetic toxicity and so on. This study consists of two parts and investigated in two companies respectively. The objective of part one was to understand hazard status of occupational harmful factors in thermometer factory and investigate occupational health status and its influencing factors of workers exposed to mercury. The objective of part two was to understand the effects of mercury on urinary8-Hydroxydeoxy guano sine (8-OHdG) level, and the influencing factors of8-OHdG.Part I Analysis of Influencing Factors of Health Status about Workers Occupational Exposed to MercuryObjective To understand hazard status of occupational harmful factors in thermometer factory and investigate occupational health status and its influencing factors of workers exposed to mercury.Methods An occupational health survey was performed to workplace, occupational health examination and questionnaires were performed to workers exposed to mercury, according to relevant national standards and norms. Noise level of workplace was measured by Quest NoisePro sound level meter. Gas chromatography was used to measure LPG of workplace. Mercury concentration in the air of workplace was detected by atomic fluorescence spectrometry. Cold atomic absorption spectrometric mothed (II) acidic stannous chloride reduction method was used to detect urinary mercury concentration. Urinary β2-microglobulin (β2-MG) was detected using immunoturbidimetric method. Urinary retinol binding protein (RBP) was detected using immune turbidimetric method. Occupational health examination was complied according to Technical specifications for Occupational Health Surveillance (GBZ188-2007). Questionnaire survey included general, occupational history, personal history, prevalence of disease, past and family history, symptoms and signs. SPSS13.0software was used for statistical analysis. Results The main occupational hazard in the production process of thermometer factory was mercury vapor. Sixteen out of nineteen detection points described in STEL and TWA were out of limits and the disqualification rate was84.2%. Significant difference of mercury concentration in the air was showed in different post (F=17.389, P<0.001). Urinary mercury concentration detected in263workers, of whom46were males,217were females. The mean age was40.08±9.146years and the average workyear was8.42±7.631years. The geometric mean of urinary mercury concentration was194.28μg/gCr (range from7.9to2949.7μg/gCr), of which211workers were greater than35μg/gCr and the over standard rate was80.2%. Urinary mercury concentration were statistically significant difference in different posts (χ2=96.166, P<0.001) and in different working year groups (χ2=11.561, P=0.009). Neurasthenia, including dizziness, insomnia, fatigue, forgetfulness was observed in274mantime. Oral problems including brushing bleeding, mouth ulcer was observed in121mantime. There were14people tremor,5people irritability and5people anxiety. Quartile method was used to separate age, working years, urinary mercury concentration into four groups. Insomnia (P=0.034) and mouth ulcer (P=0.018) were significant difference in different age groups. It was easier to insomnia and suffering from mouth ulcer when older. Incidence of mouth ulcer (P=0.007) and tremor (P=0.002) were significant difference in different working year groups. It was easier to suffering from mouth ulcer and tremor when working year was longer. Statistically significant difference was found in incidence of mouth ulcer between different urinary mercury concentration groups. Urinary β2-MG detected in255workers, of whom46were males,209were females. The mean age was40±9.206years and the average workyear was8.22±7.424years. The median of urinary β2-MG was1.35μmol/molCr (range from0.12to46.29μmol/molCr). Urinary RBP detected in255workers, of whom46were males,209were females. The mean age was40.05±9.177years and the average workyear was 8.31±7.482years.The median of urinary RBP was1.59μmol/molCr (range from0.00to48.40umol/molCr). A positive correlation was exhibited between urinary β2-MG concentration and urinary mercury concentration (r=0.158, P=0.012). Urinary RBP level was significant difference in different urinary mercury concentration groups (χ2=15.297, P=0.002). A positive correlation was exhibited between urinary RBP concentration and urinary mercury concentration (r=0.214, P=0.001). A positive correlation was observed between urinary RBP concentration and urinary β2-MG concentration (r=0.313, P<0.001).Conclusion Mercury concentration in the air and in the urine seriously exceeded standard in this thermometer factory. It was severe harmful to workers. Older age, longer length of service and higher urinary mercury concentration were risk factors of mouth ulcer. Longer length of service was risk factor of tremor. Increasing RBP level was caused by exposed to mercury.Part II An Investigation of Urinary8-Hydroxy-deoxyguanosine Concentration and Its Influencing Factors of Workers Occupational Exposed to MercuryObjective To inverstigate the effects of mercury on urinary8-OHdG level, and the influencing factors of8-OHdG.Methods According to "Methods for Determination of Mercury and Its Compounds in the Air of Workplace"(GBZ/T160.14-2004) to determinate mercury concentration in the air of workplace. Questionnaires were performed to volunteers including general, occupational history, personal history, prevalence of disease, past and family history, symptoms and signs. Urinary8-OHdG level was detected by ultra-high performance liquid chromatography/tandem mass spectrometry. All statistical analyses were accomplished by SPSS13.0software.Results All detection points of mercury concentration in workplace were out of limits showed by TWA. Statistically significant difference of mercury concentration in the air of workplace (F=138.714, P<0.001) and in urinary mercury concentration (χ2=44.531, P<0.001) was found in different posts. A positive correlation was determined between mercury concentration of workplace and urinary mercury concentration (r=0.624, P<0.001). There were139workers exposed to mercury, of whom22were males,117were females. The mean age was38.49±8.097years and the average workyear was14.63±9.439years. The median of urinary8-OHdG was3.94μg/gCr (range from0.00to30.71μg/gCr). There were155non-exposed people, of whom31were males,124were females. The mean age was40.25±7.486years and the average length of service was15.34±7.921years. The median of urinary8-OHdG was2.60μg/gCr (range from0.00to10.94μg/gCr). Significant difference was found between this two groups (Z=-4.808, P<0.001). Increasing of urinary8-OHdG level was caused by exposed to mercury. Urinary8-OHdG concentration in female was higher than male, OR(95%CI) value was4.71(1.65～13.46). High urinary mercury concentration was risk factors of urinary8-OHdG concentration.8-OHdG concentration in urine of smokers was higher than non-smokers, OR(95%CI) value was6.65(1.71-25.82).Conclusion Exposure to mercury can cause oxidative DNA damage in vivo, increase urinary8-OHdG level. Sex, urinary mercury concentration, and smoking were influencing factors of oxidative DNA damage in vivo. |
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