OBJECTIVETo investigate the possible effects of long-term exposure to dust containing thorium and thoron progeny on dust-exposed miners.

METHODSA negative, high voltage, exhaled thoron progeny measurement system was used to estimate the miners' thorium lung burden.

RESULTSThe highest thorium lung burden of 638 miners was 11.11 Bq. The incidence of stage 0(+) pneumoconiosis was higher among dust-exposed miners. Lung cancer mortality of the dust-exposed miners was significantly higher than that of controls (P < 0.005).

CONCLUSIONThere is a difference in cancer rates between those who have long-term exposure to dust containing thorium (in which carcinogenic ThO(2) and SiO(2) exist) and thoron progeny and those who have not.

Air Pollutants, Radioactive ; adverse effects ; Body Burden ; China ; epidemiology ; Dust ; Follow-Up Studies ; Humans ; Lung Neoplasms ; epidemiology ; Mining ; Occupational Diseases ; epidemiology ; Occupational Exposure ; adverse effects ; Thorium ; adverse effects

Air Pollutants, Occupational ; Humans ; Occupational Exposure ; Styrene

Air Pollutants, Occupational ; analysis ; Solvents ; analysis

Introduction: Air pollutants that possessed genotoxic properties have the potential to induce genetic damage. Micronuclei (MN) frequency is used as an indicator for identifying potential genotoxic exposures. A comparative cross-sectional study was carried out among primary school children in a petrochemical industrial area (N=111, Kemaman) and a rural (N=65, Dungun) area in Terengganu. Methods: Validated questionnaires were distributed to obtain the respondents’ socio-demographic data, previous exposure and reported respiratory illness. The frequency of micronuclei was assessed in collected buccal mucosa samples of children. The air monitoring was also carried out at 6 selected schools. Results: Results from the statistical analysis carried out showed significant differences with p=0.001 for all parameters assessed between areas, which included ultrafine particles, UFP (z = -4.842), PM2.5 (z = -10.392), PM10 (z= -11.074) NO2 (z = -11.868), SO2 (z = -5.667), relative humidity (z = -5.587). The MN frequency was statistically significant with PM2.5 (χ2= 17.78, p=0.001) and PM10 (χ2= 15.429, p =0.001). The statistical analysis also showed a significant association between UFP and coughing (PR=2.965, 95% CI=1.069-8.225). The multiple logistic regression analysis showed that the main pollutants influencing MN frequencies were UFP and NO2 with UFP (PR=1.877, 95%CI= 1.174-3.002) and NO2 (PR=1.008, 95%CI= 1.001-1.015). Conclusion: This study demonstrated that exposure to air pollutants may increase the risk of respiratory illness and may induce MN formation among children.
Air pollutants

OBJECTIVETo explore the quantitative relationship between the dust mass concentration and fiber number concentration of refractory ceramic fibres.

METHODSA typical refractory ceramic fiber plant was selected as the study site. Fifty-three paired samples of total dust mass concentration and fiber number concentration were collected using the long-time fixed site mode. The total dust mass concentration was measured according to the GBZ/T 192.1-2007 (Measurement of dust in the air of workplace, part 1: Total dust concentration). Membrane filter method/phase-contrast optical microscopy was used to determine the fiber number concentration. Univariate analysis was used to describe the distribution of the two concentrations and their ratio. Spearman rank correlation, as well as linear regression, logarithmic curve, polynomial, power function, and exponential curve model, were used to explore the relationship between the two concentrations. Results The range of the total dust mass concentration (x) was 0.45-13.82 mg/m3. The range of the fiber number concentration (y) was 0.01-1.04 f/ml. The range of the ratio (x/y) was 4-158. All of the three parameters did not follow normal distribution (P<0.000 1). The two concentrations showed a positive correlation (r,=0.705 22, P< 0.000 1). All the coefficients of determination (R2) of linear regression, logarithmic curve, polynomial, power function, and exponential curve model were relatively low. The trinomial curve model had the highest R2 (0.6848) and the fitted equation was y=-0.001, 1x+0.010 4x2+0.101 4x-0.055 1.

CONCLUSIONThere is a positive correlation between the total dust mass concentration and fiber number concentration of refractory ceramic fibers. However, there is no fixed regression relationship between the two concentrations, and neither is a definite coefficient which can be used to convert each other. The two concentrations cannot be replaced by each other.

Air Pollutants, Occupational ; analysis ; Ceramics ; Dust ; analysis ; Occupational Exposure

Air Pollutants, Occupational ; toxicity ; Humans ; Occupational Exposure ; adverse effects ; Welding

Objective: To establish a method for the determination of butyronitrile and isobutyronitrile in the air of workplace by gas chromatography. Methods: In March 2020, butyronitrile and isobutyronitrile in the air of workplace was collected by silica gel, eluted with methanol, separated and determined by gas chromatogram with flame ionization detector, the characteristics of determination of nitrile and isobutyronitrile by gas chromatography were analyzed. Results: The limit of detection for butyronitrile and isobutyronitrile was 0.33 μg/ml. The linear range of butyronitrile determined by this method was 1.60-1600.00 μg/ml, y=2.295x-3.480, and the coefficient correlation was 0.99998, and the minimum detection concentration was 0.22 mg/m(3) (collected sample volume was 1.50 L) . The within-run precisions were 2.43%-4.12%, the between-run precisions were 1.72%-3.70%, and the desorption rates were 93.26%-98.41%. The linear range of isobutyronitrile determined by this method was 1.52-1520.00 μg/ml, y=2.208x-0.102, and the coefficient correlation was 0.99998, and the minimum detection concentration was 0.22 mg/m(3) (collected sample volume was 1.50 L) . The within-run precisions were 2.52%-3.22%, the between-run precisions were 1.20%-3.82%, and the desorption rates were 96.85%-102.50%. The sealed samples could be stored at least 10 days at room temperature without significant loss. Conclusion: The method has the advantages of good precision, high sensitivity and simple operation. It is suitable for the simultaneous determination of butyronitrile and isobutyronitrile in the air of workplace.
Air Pollutants, Occupational/analysis* ; Chromatography, Gas/methods* ; Nitriles ; Workplace

Objective: To establish a method for the determination of acetylacetone in the air of workplace by gas chromatography. Methods: In August 2020, acetylacetone in the air of workplace was collected by silica gel tube, eluted with methanol, separated and detected by gas chromatography with flame ionization detector. The detection limit and precision of the method were also analyzed. Results: The linear range of acetylacetone was 1.95-1950.60 μg/ml with the regression equation of y=0.815x-3.667, and the correlation coefficient was 0.99993. The limit of detection of the method was 0.18 μg/ml and the minimum detection concentration was 0.12 mg/m(3) (collected sample volume was 1.50 L). The within-run precisions were 1.08%-4.11% and the between-run precisions were 1.98%-2.80%. The desorption rates were 99.68%-100.45%. The sealed samples could be kept at least 15 days at room temperature without significant loss. Conclusion: The solvent desorption-gas chromatography method for the determination of acetylacetone has good precision, high sensitivity and simple operation, and is suitable for the determination of acetylacetone in the air of the workplace.
Solvents ; Air Pollutants, Occupational/analysis* ; Chromatography, Gas/methods* ; Workplace

OBJECTIVETo develop a method for determining epichlorohydrin in the workplace air by gas chromatograph-electron capture detector (GC-ECD).

METHODSEpichlorohydrin in the workplace air was collected by activated charcoal tubes, desorbed using acetone, and analyzed by GC-ECD.

RESULTSA good linearity was obtained in the range of 1.0-50 µg/mL (r=0.999 7). The detection limit was 0.012 µg/ml, while the recovery rate was 88.1% and relative standard deviation ranged from 1.11% to 3.57%. The samples could be stored for seven days at room temperature.

CONCLUSIONThis method effectively eliminates the interferences of alkanes on determination of epichlorohydrin and improves the sensitivity by 1 to 2 orders of magnitude, which can solve the problem of detection limit above standard in GBZ/T 160.58-2004.

Air Pollutants, Occupational ; analysis ; Charcoal ; Chromatography, Gas ; Epichlorohydrin ; analysis ; Workplace

Air Pollutants, Occupational ; analysis ; Dust ; analysis ; Environmental Monitoring ; methods ; Workplace