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{L-End}Objective To analyze the spectrum characteristics of noise hazards in the metal products industry. {L-End}Methods A total of six metal product industries were selected as research subjects using stratified sampling method. The noise intensity (A/C-weighted) and noise spectrum (Z-weighted) of workplaces and job positions were detected. The characteristics of the noise spectrum of each job position were analyzed using the difference between equivalent continuous C-weighted sound pressure level (LCeq)-equivalent continuous A-weighted sound pressure level (LAeq), the dominant frequency of the noise spectrum, and cluster analysis methods. {L-End}Results The workplace noise and job position noise of 11 main noise positions in the metal products industry were exceeded national standard, with incidence of 69.2% and 78.1%, respectively. The average of normalization of equivalent continuous A-weighted sound pressure level to a normal 40 hours working week exceeded the national standard in 100.0% of hydraulic workers, welders, and ultrasonic cleaning workers. The result of spectrum analysis showed that the noise in the metal product industry was mainly broadband. The noise of the collision welder position was classified as low-frequency broadband noise, while the noise of the painter position was classified as low-frequency narrowband noise. The noise spectrum characteristics of other positions were similar and classified into one category, all of which were broadband noise. Among them, numerical control lathe workers, welders, threaders, machinists, and cutters were exposed to high-frequency broadband noise, while press workers were exposed to mid-frequency broadband noise, and grinders, hydraulic workers, and ultrasonic cleaning workers were exposed to low-frequency broadband noise. The detection rate of binaural high-frequency hearing threshold improvement among workers was 61.7%, and there was no statistical correlation between the detection rate of binaural high-frequency hearing threshold improvement and the noise level intensity of each spectrum. {L-End}Conclusion The level of noise hazards in the metal products industry is severe. Effective engineering control measures and hearing protection measures should be implemented based on the spectral characteristics of noises.
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Objective@#To develop a method for Simultaneous and rapid determination of 12 rodenticides including pindone, vacor, coumatetralyl, warfarin, diphacinone, coumachlor, chlorphacinon, difenacoum, brodifacoum, bromadiolone, difethialone and flocoumafen in whole blood and urine samples by high performance liquid chromatography-tandem mass (LC-MS-MS) .@*Methods@#The whole blood samples were precipitated with acetonitrile, purified by OstroTM 96-well plate, The urine samples were extracted by acetonitrile, and then separated on a ODS column, analyzed with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) . The external standard calibration were tested.@*Results@#A good linearity was observed in their respective concentration ranges of 12 rodenticides. The related coefficients were 0.993 0~0.999 8. The limit of detections were 0.05 μg/L~1.4 μg/L. The rates of recovery were 92.5%~118.0%. The relative standard deviations were between 0.8%~17.3%.@*Conclusion@#The method was simple, rapid, sensitive, accurate and suitable for simultaneous detection of the 12 rodenticides in whole blood and urine samples of intoxicated patients.
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<p><b>OBJECTIVE</b>To understand the exposed positions and levels of indium and its compounds in manufacture of liquid crystal displays, and to evaluate the degree of occupational hazard from indium and its compounds.</p><p><b>METHODS</b>On-site investigation of occupational health, occupational hazard monitoring, and occupational health examination were used to evaluate the degree of occupational hazard from indium and its compounds in three manufacturers of liquid crystal display panel in Shenzhen, Guangdong, China.</p><p><b>RESULTS</b>The time-weighted average (TWA) and short-term exposure limit (STEL) concentrations of indium and its compounds to which sputtering machine operating positions were exposed were less than 0.002~0.004 mg/m³ and 0.006~0.007 mg/m³, respectively, both of which complied with the National Hygienic Standard (PC-TWA = 0.1 mg/m³; PC-STEL = 0.3 mg/m³); the TWA and STEL concentrations of indium and its compounds to which grinding positions were exposed were 0.114~2.98 mg/m³ and 0.31~10.02 mg/m³, respectively, both of which exceeded the National Hygienic Standard with the highest concentration 33-fold higher than the standard. No significant health damages were found in exposed workers according to the results of occupational health examination.</p><p><b>CONCLUSION</b>The grinding positions are the key to the control of occupational hazard from indium and its compounds in manufacture of liquid crystal display panel. The workers should be equipped with the anti-particulate full-face respirator, which is an effective way to prevent occupational hazard from indium and its compounds.</p>