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Ho Chun Choi 5 Articles
Concentrations of lead, iron and zinc in blood of coal workers' pneumoconiosis patients.
Ho Chun Choi, Ho Keun Chung, Hae Jeong Kim
Korean J Prev Med. 1989;22(4):486-494.
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AbstractAbstract PDF
Lead, iron, and zinc concentrations in whole blood were determined by atomic absorption spectrophotometry, using a simple one-step dilution procedure, which were measured in 3 groups, 98 officers unexposed to dust or to metal, 58 coal miners without pneumoconiosis, and 113 coal workers' pneumoconiosis (CWP) patients. The results were as follows; 1. The precisions (C. V.%) of lead, iron, and zinc in blood were 12.65+/-6.95%, 1.47+/-1.25% and 6.35+/-3.34%, respectively. 2. Lead and zinc in blood showed the log-normal distribution unlike iron in blood which showed normal distribution. 3. Lead, iron, and zinc concentrations in blood of 3 groups were follows. There was significant difference of concentration far zinc in blood by groups statistically. 4. The difference of lead, iron, and zinc concentrations in blood was not significant (p>0.05) by profusion on chest radiographs.
Summary
Quantitative Analysis of Quartz, Mica, and Feldspar in Respirable Coalmine Dust in Taebaek Area by Fourier Transform Infrared Spectrophotometry.
Ho Chun Choi, Yong Hee Cheon, Hae Jeong Kim, Jeong Joo Lee
Korean J Prev Med. 1988;21(2):271-283.
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AbstractAbstract PDF
A Fourier transform infrared spectrophotometric method was described for the determination of quartz, mica(sericite) and feldspar(potassium feldspar) in respirable dust in Taebaek area. The results were as follows; 1) The concentration of minerals were determined from the intensity of absorption peak of quartz at 799 cm-1, sericite at 539 cm-1, and potassium feldspar at 648 cm-1 respectively. 2) The precision(C. V. %) for the quartz determination was 7.70+/-2.68 % from 10 to 200 microgram of quartz. 3) The precision for the sericite determination was 16.34+/-6.82 % from 30 to 500 microgram of serictite. 4) The precision for the potassium feldspar determination was 5.28+/-1.74 % from 30 to 500 microgram of potassium feldspar. 5) The concentration of respirable dust in Taebaek area was 4.90+/-3.29 mg/m3(0.4-93.7%), percent quartz was 1.80+/-4.14% (0.01-20.56%), percent sericite was 11.37+/-6.43% (0.00-29.69%), percent potassium feldspar was 8.15 % (n=7, 3.41-19.70%). 6) The difference of respirable coal dust, quartz, and sericite concentration in drilling, coal cutting, hauling and separating was significant respectively (p<0.05).
Summary
Quartz Concentration and Respirable Dust of Coal Mines in Taeback and Kangneung Areas.
Ho Chun Choi, Yong Hee Cheon, Young No Yoon, Hae Jeong Kim
Korean J Prev Med. 1987;20(2):261-269.
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AbstractAbstract PDF
In order to investigate working conditions of underground coal mines, this work was undertaken to evaluate the respirable dust and the concentration of quartz in Taeback and Kangneung areas. The concentration of quartz was determined by Fourier Transform Infrared Spectrophotometry. The results were as follows; 1) The concentration of respirable dust of drilling and coal face in Taeback and Kangneung areas were as followed. 2) Distribution of respirable dust was well fitted to the long-normal distribution and geometric mean value was log(-1) 0.37+/-log(-1) 0.47 (2.34+/-2.95) mg/m3. 3) The difference of respirable dust concentrations in Taeback and Kangneung areas was not significant statistically (p>0.05). 4) The concentration of quartz of drilling and coal face in Taeback and Kangneung areas were as followed. 5) Distribution of quartz concentrations was well fitted to the log-normal distribution and geometric mean value was log(-1) 0.33+/-log(-1) 0.45 (2.14+/-2.82)%. 6) The difference of quartz concentrations in Taeback and Kangneung areas was not significant (p>0.05), but significant at drilling sites and coal faces (p<0.05).
Summary
Relationship between the Measurement Values of the Digitial Dust Indicator and Personal Dust Sampler.
Young No Yoon, Jeong Joo Lee, Ho Keun Chung, Ho Chun Choi
Korean J Prev Med. 1987;20(2):255-260.
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AbstractAbstract PDF
The digital dust indicator (Sibata P-5), one of the direct-reading instruments was evaluated for the respirable dust in the underground coal mine environments. As a reference, respirable dust was determined using three cyclones and/or impactors. All the tests were performed on aerosol in twenty underground coal mines. The coefficients of mass-relative concentration were 0.067+/-0.054 (Mean+/-Standard deviation) (range: 0.006-0.172). The relationship between relative concentration and temperature was not significant statistically. Also, the relationship of relative concentration and relative humidity was not significant. Mass concentration and relative concentration were 5.31+/-5.22 mg/m3 and 162+/-163 CPM (Mean+/-Standard deviation) respectively. The range of mass concentration was 1.22-22.69 mg/m3; relative concentration 16-628 CPM. The relationship of mass concentration and relative concentration was not significant in these ranges.
Summary
Measurement conditions for cadmium in urine by flame atomic absorption spectrophotometry.
Ho Chun Choi, Kyou Chull Chung
Korean J Prev Med. 1984;17(1):269-280.
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AbstractAbstract PDF
The optimum conditions for measuring cadmium content of less than 0.2ppm by flame atomic absorption spectrophotometry were investigated. The cadmium in urine was extracted by APDC-MIBK for the analysis by atomic absorption spectrophotometry after ashing them by a wet method. 1. Optimum conditions by APDC-MIBK and DDTC-MIBK extractions. The acidic aqueous solution was prepared with appropriate amount of 0.1N nitric acid, 5ml of 25% (W/V) sodium potasstum tartarate, 10ml of saturated ammonium sulfate, and 2ml of 2% APDC(or 1 ml of 5% DDTC) chelating agent. The total volume of solution was adjusted to 55ml and pH to 2~10 (or 7~10). The aqueous solution was extracted with 10ml MIBK. Concentration of Triton X-100 did not effect the absorbance for APDC-MIBK extraction of cadmium, but absorbance decreased as the concentration increased for DDTC-MIBK extraction. The sensitivity and detection limits for the cadmium determination from APDC-MIBK extraction were 0.0038ppm and 0.0102, 0.0022ppm and 0.0116 for DDTC-MIBK, and 0.0132ppm and 0.0034 for 0.1N nitric acid. APDC-MIBK and DDTC-MIBK extractions were 3 times higher than 0.1N nitric acid for the sensitivity. 2. Excretion of cadmium in 24-hour urine by APDC-MIBK extraction. Determination of cadmium in urine by atomic absorption spectrophotometry of A.A. (Cd=2 mA) mode and B.C. (Cd=4 mA) mode and B.C. (Cd=4mA, D2=20mA) mode showed some difference (p<0.05). The difference of cadmium determination and recovery according to method of standard additions and standard calibration curve method in urine was not significant (p>0.05, 93.48+/-11.78%, 94.83+/-22.00%). Excretion of cadmium in 24-hour urine collection from normal person and variance analysis within measurement variation was not significant (p>0.05), but between inter-individual was significant (0.05). Determination of cadmium content by two different methods of flame atomic absorption spectrophotometry and dithizone colorimetry showed that the results from the two methods can be described by a regression line with a good correlation (y=1.0153x-0.2927, x=Cd by D.C., y=Cd by A.A.S., r=0.8651*, p<0.01).
Summary

JPMPH : Journal of Preventive Medicine and Public Health