Meta-analysis on the contents of trace elements in workers with occupational exposure to lead / 中华劳动卫生职业病杂志

Objective: To quantitatively evaluate the content differences of trace elements in workers with occupational exposure to lead. Methods: In January 2021, relevant literatures on the contents of trace elements in workers with occupational exposure to lead published from 1990 to 2020 were searched through CNKI, Wanfang, VIP, PubMed, web of science and Embase. Screened and extracted the literatures, and evaluated the quality of the included literatures with Newcastle Ottawa Scale. Meta analysis was performed with Review Manager 5.3 software, and standardized mean difference (SMD) and its 95% confidence interval were used as effect indicators. Results: A total of 20 literatures were included, and the quality scores were 5-7. The results of Meta-analysis showed that compared with the control group, the contents of blood zinc (SMD=-1.01, 95%CI: -1.53, -0.49) , hair zinc (SMD=-0.17, 95%CI: -0.33, -0.01) , hair copper (SMD=-0.50, 95%CI: -1.01, 0) , hair iron (SMD=-3.91, 95%CI: -5.80, -2.03) and hair manganese (SMD=-1.09, 95%CI: -2.02, -0.15) in occupational lead exposure group were significantly lower (P<0.05) . Compared with the control group, the content of cobalt in hair of occupational lead exposure group (SMD=1.41, 95%CI: 0.72, 2.10) was higher, and the difference was statistically significant (P<0.05) . There was no significant difference in the contents of blood chromium, blood copper, blood iron, blood manganese, blood selenium and hair nickel between the two groups (P>0.05) . Conclusion: Workers with occupational exposure to lead have abnormal trace elements.

Determination of methyl isobutyl ketone in urine by headspace coupled with gas chromatography-mass spectrometry / 中华劳动卫生职业病杂志

Objective: To establish a method for the determination of methyl isobutyl ketone (MIBK) in urine samples by headspace-gas chromatography-mass spectrometry. Methods: Automatic headspace sampling technique was adopted to optimize the headspace conditions (headspace bottle heating temperature and equilibration time) and gas chromatographic conditions. A total of 5 ml samples were taken and added with 3.0 g ammonium sulfate into a 20 ml headspace bottle. After heated at 60 ℃ for 30 mins, gas from the upper part of headspace bottle was injected into gas chromatography with an injection volume of 100 μl. The target was separated by HP-5MS UI (30 m×0.25 mm×0.25 μm) capillary column and then detected by mass spectrometry detector. The retention time and external standard method were used for qualitative and quantitative analysis of MIBK in samples, respectively. Results: The standard curve of MIBK showed significant linearity between 20.0-1 000.0 μg/L. The standard curve was y=62.9x-652.5, and the correlation coefficient r=0.9998. The detection limit of MIBK was 5.0 μg/L and the quantification limit of MIBK was 16.0 μg/L. The average recovery rate was 95.3%~100.2% at three spiked concentrations of low (50.0 μg/L) , medium (200.0 μg/L) and high (500.0 μg/L) . The intra-day and inter-day precisions were 1.7%~3.8% (n=6) and 1.2%~4.0% (n=6) respectively. This method was stable for the determination of MIBK, and the urine could be kept 14 d at -20 ℃ without significantly loss. Conclusion: This method is proved to be simple, practical and highly sensitive. It can satisfy the request for the determination of urine samples of workers exposed to MIBK.

A retrospective cohort study on abnormal blood lead levels in lead-exposed workers in a storage battery factory / 中国职业医学

OBJECTIVE: To analyze the influencing factors of high blood lead levels in lead-exposed workers of a storage battery factory. METHODS: By the typical sampling method,lead-exposed workers were chosen as study subjects for a three-year retrospective cohort study starting from September of 2011 and ending in September of 2014. The starting blood lead level was < 400. 0 μg / L and ending blood lead level was ≥400. 0 μg / L( abnormal level). The influencing factors of abnormal blood lead level were analyzed by the COX regression analysis method. RESULTS: There were 244 lead-exposed workers included in this study. The median( M) working years of baseline lead exposure was 6. 3( 0. 7-35. 9) years,the M of baseline blood lead level was 321. 5( 215. 7-398. 7) μg / L by September of 2011. During the 3 years,there were 78 workers found to have abnormal blood lead levels,with an abnormality rate of 32. 0%. The multivariable COX regression analysis indicated that the workers with following situations had relative higher incidences of abnormal blood lead level:working without masks,baseline blood lead level over 300. 0 μg / L,the air concentration of lead in workplace beyond the standard and the workers exposed to lead for over 5. 0 years,their relative risk ratios were 6. 89,4. 00,9. 02 and 2. 93 times of those workers with the opposite situations,respectively( P < 0. 01). CONCLUSION: Measures should be taken to prevent and control the occupational chronic lead poisoning especially in those lead-exposed workers who don't wear masks during work,whose baseline blood lead level was over 300. 0 μg / L,whose air concentrations of lead in workplace were beyond the standard and whose lead exposure year was over 5. 0 years.