Maximum Allowable Concentration ; Occupational Exposure

Maximum Allowable Concentration ; Mineral Fibers ; analysis ; Occupational Exposure ; analysis

China ; Humans ; Maximum Allowable Concentration ; Occupational Exposure ; prevention & control

Dust ; Humans ; Maximum Allowable Concentration ; Occupational Exposure ; adverse effects ; Research Report ; Silicon Dioxide ; toxicity

Air Pollutants, Occupational ; adverse effects ; analysis ; Dust ; analysis ; Environmental Monitoring ; instrumentation ; methods ; Humans ; Industry ; Inhalation Exposure ; statistics & numerical data ; Maximum Allowable Concentration ; Occupational Exposure ; statistics & numerical data ; Quartz

OBJECTIVETo study the effects of carbon disulfide exposure within the national maximum allowable concentration(MAC) on blood pressure and electrocardiogram, and associations with selected factors.

METHODSWorkers in a chemical fiber factory were divided into two groups based on the type of work: a high exposure group (HEG) of 821 individuals and a low exposure group (LEG) of 259. The CS2 concentration at workplace was controlled under the national MAC. A set of 250 randomly selected people taking routine physical check-ups in the same period and hospital constituted the control group. The systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured on the arm, and the pulse pressure (PP) and mean arterial blood pressure (MABP) were calculated based on SBP and DBP. The blood pressure data, along with the results of the routine 12-lead electrocardiography taken at rest and records on gender, age, years of work, type of work, and concentrations of triglycerol, cholesterol, and glucose in blood, were compiled for analyses. Risk factors upon CS2 exposure for the increase of blood pressure and occurrence of electrocardiogram abnormalities were identified and rationalized.

RESULTSSignificant difference (P < 0.01) in the average values of SBP, DBP, MABP, and the corresponding abnormality incident rates was found between HEG and LEG, and between HEG and the control group. For both HEG and LEG, the incident rate of DBP abnormality (high DBP) is nearly two times as high as that of SBP. Type of work is the largest risk factor in both the high SBP and high DBP subgroups, with odds ratios (OR) of 2.086 and 2.331 respectively, and high CS2 exposure presents more than double the risk than low exposure. On the incident rate of ECG abnormalities, both exposure groups are significantly different (P < 0.01) to the control group. High SBP in LEG and high DBP in HEG were found to be significant risk factors (OR = 3.531 and 1.638 respectively), while blood glucose appears to be a protective factor (OR = 0.747), appealing to further investigation. Meanwhile, factors like years of work and cholesterol were found to be risk factors in the high SBP subgroup with low exposure, and in the high DBP subgroup with high exposure. Within HEG, high DBP is the only blood pressure-related risk factor found for the incident of left ventricular high voltage (OR = 4.140), as is high SBP for LEG (OR = 4.776). High PP is the only risk factor found for repolarization disturbances within LEG (OR = 20.417). While blood sugar is a risk factor for origin disturbances, it is a protection factor for left ventricular high voltage (OR = 0.633).

CONCLUSIONThe damage of CS2 done to the cardiovascular system is a gradual process. Both early and very low level exposures are detrimental to the human circulatory system. Below the National MAC limit, the toxic effect of CS2 to the cardiovascular system increases with time and level of exposure. The effect of CS2 on DBP is more significant than on SBP, which indicates that CS2 may affect peripheral resistant blood vessels more than the artery. The abnormalities of ECG of workers exposed to CS2 are not only the result of high blood pressure on the heart, but also of the direct toxicity of CS2 on heart and blood vessels.

Adult ; Blood Pressure ; drug effects ; Carbon Disulfide ; administration & dosage ; adverse effects ; Electrocardiography ; drug effects ; Female ; Humans ; Male ; Maximum Allowable Concentration ; Middle Aged ; Occupational Exposure ; adverse effects ; Retrospective Studies ; Young Adult

Introduction: Water-based metalworking fluid (MWF) provides a suitable environment for microbes to grow. This study aimed at identifying the level and species of microbial contamination of MWF in a metal machining factory and to determine the corresponding Immunoglobulin G (IgG) levels in the workers’ blood samples. Methods: Total of 298 workers in the production section of a metal machining factory, the production section using MWF as coolant fluid, were involved in this study. The Analytical Profile Index system was used to identify the species of microbes isolated from MWF bulk and air samples. Tryptone soya agar was used to incubate unknown bacteria, and sabouraud dextrose agar was used for unknown fungi. The level of IgG antibodies in workers’ blood were measured as an indicator of the exposure to the microbes isolated from MWF, corresponded to the microbial species isolated from MWF. Results: The most dominant microbes isolated from the channels were Candida albicans, Klebsiella pneumoniae, E. coli and Pseudomonas aeruginosa. A total of 21 (34.4%) workers were positively exposed to E. coli, 30 (42.2%) to Pseudomonas aeruginosa, and 45(75%) exposed to Candida albicans. Also, the mean level of optic density of IgG to Klebsiella pneumoniae was 0.415 (0.02). Conclusion: Water-based metalworking fluid in this metal machining factory was contaminated with bacteria and fungi. The workers in the production section were exposed to MWF as well as the microbes present in MWF. The level of IgG in blood was the biomarkers for occupational exposure to microbial contaminant MWF.
Occupational exposure

OBJECTIVES: The level of benzene exposure in the petrochemical industry during regular operation has been well established, but not in turnaround (TA), where high exposure may occur. In this study, the characteristics of occupational exposure to benzene during TA in the petrochemical companies were investigated in order to determine the best management strategies and improve the working environment. This was accomplished by evaluating the exposure level for the workers working in environments where benzene was being produced or used as an ingredient during the unit process. METHODS: From 2003 to 2008, a total of 705 workers in three petrochemical companies in Korea were studied. Long- and short-term (< 1 hr) samples were taken during TAs. TA was classified into three stages: shut-down, maintenance and start-up. All works were classified into 12 occupation categories. RESULTS: The long-term geometric mean (GM) benzene exposure level was 0.025 (5.82) ppm (0.005-42.120 ppm) and the short-term exposure concentration during TA was 0.020 (17.42) ppm (0.005-61.855 ppm). The proportions of TA samples exceeding the time-weighted average, occupational exposure level (TWA-OEL in Korea, 1 ppm) and the short-term exposure limit (STEL-OEL, 5 ppm) were 4.1% (20 samples of 488) and 6.0% (13 samples of 217), respectively. The results for the benzene exposure levels and the rates of exceeding the OEL were both statistically significant (p < 0.05). Among the 12 job categories of petrochemical workers, mechanical engineers, plumbers, welders, fieldman and scaffolding workers exhibited long-term samples that exceeded the OEL of benzene, and the rate of exceeding the OEL was statistically significant for the first two occupations (p < 0.05). CONCLUSION: These findings suggest that the periodic work environment must be assessed during non-routine works such as TA.
Benzene ; Korea ; Occupational Exposure ; Occupations ; Threshold Limit Values

OBJECTIVES: The level of benzene exposure in the petrochemical industry during regular operation has been well established, but not in turnaround (TA), where high exposure may occur. In this study, the characteristics of occupational exposure to benzene during TA in the petrochemical companies were investigated in order to determine the best management strategies and improve the working environment. This was accomplished by evaluating the exposure level for the workers working in environments where benzene was being produced or used as an ingredient during the unit process. METHODS: From 2003 to 2008, a total of 705 workers in three petrochemical companies in Korea were studied. Long- and short-term (< 1 hr) samples were taken during TAs. TA was classified into three stages: shut-down, maintenance and start-up. All works were classified into 12 occupation categories. RESULTS: The long-term geometric mean (GM) benzene exposure level was 0.025 (5.82) ppm (0.005-42.120 ppm) and the short-term exposure concentration during TA was 0.020 (17.42) ppm (0.005-61.855 ppm). The proportions of TA samples exceeding the time-weighted average, occupational exposure level (TWA-OEL in Korea, 1 ppm) and the short-term exposure limit (STEL-OEL, 5 ppm) were 4.1% (20 samples of 488) and 6.0% (13 samples of 217), respectively. The results for the benzene exposure levels and the rates of exceeding the OEL were both statistically significant (p < 0.05). Among the 12 job categories of petrochemical workers, mechanical engineers, plumbers, welders, fieldman and scaffolding workers exhibited long-term samples that exceeded the OEL of benzene, and the rate of exceeding the OEL was statistically significant for the first two occupations (p < 0.05). CONCLUSION: These findings suggest that the periodic work environment must be assessed during non-routine works such as TA.
Benzene ; Korea ; Occupational Exposure ; Occupations ; Threshold Limit Values

China ; Occupational Exposure ; Threshold Limit Values ; Ultraviolet Rays