A measurement of indoor microorganism using Reuter Centrifugal Air Sampler(RCS) was undertaken during October 1991-February 1999 and 6-Stage Cascade Air Sampler was undertaken during May 2001-June 2001 in Seoul. The results were as follows : 1. The average of total microorganism collected on the agar strip GK-A media were, in the order, subway station, hospital, underground shopping center, department store, book store, theater, sports facility, educational institution, office building in sites. 2. The average of staphylcocci collected on the agar strip GK-S media, in the order, were subway station, underground shopping center, hospital and department store, department store, theater, office building, sports facility and educational institution in sites. 3. The average of fungus collected on the agar strip GK-HS media, in the order, were Underground hospital, shopping center, theater, subway station, department store, book store, sports facility, educational institution, and office building in sites

Many adolescents stay long time in the PC game room and are exposed to much of tobacco smoke. To evaluate the effect of passive smoking in the PC game room, airborne nicotine concentrations and urinary cotinine concentrations were measured for 20 adolescents at 2 PC game rooms in Sung-nam city. And the subjects were interviewed for duration and time in PC game room and smoking pattern. Subjects are composed of each of 10 smokers(5 males and 5 females) and 10 non-smokers(5 males and 5 females). They stayed for three hours in the PC game room without smoking. Concentrations of nicotine in smokers and non-smokers were 129.72 $\mu\textrm{g}$/㎥ and 99.99 $\mu\textrm{g}$/㎥, respectively. Urinary cotinine concentrations were increased as time goes on after exposure to nicotine and showed maximum value at 9.45 hours after nicotine exposure and were 32.21 and 110.66 $\mu\textrm{g}$/L for non-smoker and smokers. Urinary cotinine has a tendency to be increased by passive smoking. Therefore, it is recommended that the effective control for indoor air quality and extensive research be needed to reduce nicotine concentration by passive smoking in the PC game room.

Diffusive transport of volatile organic compounds(VOCs) and their degradation by bacteria in unsaturated soils are couple by poorly understood mass transfer kinetics at the gas/water interface. Determination of the fate of VOCs in unsaturated soil is necessary to evaluate the feasibility of natural attenuation as a VOC remediation strategy. The objective of this study was to develop a mechanistically based mathematical model that would consider the interdependence of VOC transport, microbial activity, and sorptive interaction in a moist, unsaturated soil. Because the focus of the model was on description of natural attenuation, the advective VOC transport that is induced in engineered remediation processes such as vapor extraction was not considered. The utility of the model was assessed through its ability to describe experimental observations form diffusion experiments using toluene as a representative VOC in well-defined soil columns that contained a toluene degrading bacterium, Pseudomonas Putida, as the sole active microbial species. The coefficient for gas-liquid mass-transfer, K$\sub$LA/, was found to be a key parameter controlling the ability of bacteria to degrade VOCs. This finding indicates that soil size and geometry are likely to be important parameters in assessing the possible success of natural attenuation of VOCs in contaminated unsaturated soils.

This study was carried out to establish the standardized analysis method in order to decide accurate concentrations of hazardous metals in the air. Acid decomposition method used usually was compared to microwave digestion method. Comparing results of tested background concentration in blank filter, we found that the magnitude of element concentration was Na, Ca, K, Mg, Al and Ba by order. The element concentrations of Glass fiber filter were higher than those of Quartz fiber filter, and the number of undetected components in Glass fiber filter was lower than that in Quartz fiber filter. Thus it is supposed that the concentration of background elements in Glass fiber filter was higher than those in Quartz fiber filter The extraction rate of microwave digestion method was superior to those of acid decomposition method during the test of blank filter as well as SRM of NIST. In case of the SRM of NIST, the average extraction efficiency of acid decomposition Method and microwave pretreatment is 53.8∼82.7％, 81.3∼97.1％, respectively. This result might be caused by the closed system of Microwave, which make outflow and loss of components less. Also microwave digestion method has other merits such as the minimization of time, reagents, and contamination. Furthermore, if the extraction condition, extraction time and used acids are optimized, the better results will be represented.

Heavy metal level and distribution in sediments and bivalves from the tidal flats along the mid-western coast, Korea, were investigated. The averages of heavy metal concentrations in sediments from 5 sampling sites ranged from 86.35-187.77mg/kg for Mn, 13.25-17.73mg/kg for Zn, 6.80-11.85mg/kg for Cr, 4.28-6.25mg/kg for Ni, 1.85-3.09mg/kg for Cu, 0.004-0.020mg/kg for Cd and 5.70-10.41mg/kg for Pb, respectively. Among the mussels of the limited body size(8.5-11cm), heavy metal concentration both in the flesh and in the whole soft parts were not strongly related to the body size. It was shown that, in S. strictus, Cu moves fast into the flesh after absorption, but Pb and Fe move very slowly. Overally, the heavy metal concentration in the flesh tends to increase with that in the whole soft parts. The concentration factors(heavy metal concentration in S. strictus/heavy metal concentration in sediment) showed that, of the examined metals, Cd is the most cumulative in the body of S. strictus, followed by Zn and Cu, while Mn, Cr, Ni and Pb are not cumulative.

This study was conducted to understand characteristics of wastewater which is discharged from small-scale dyehouse located in Seoul downtown area and to Find the appliable treatment method on the spot. The results of this study were summarized as followings. 1. The method which is used at present is mostly flocculation by coagulant or fenton oxidation. But the treatment efficiency of them are not good. 2. The results of fenton oxidation experiment demonstrated that treatment efficiency of COD was limited, which showed the need of the additional process or the improvement of existing treatment method, while the color was reduced considerably in optimal condition. 3. The optimal condition of fenton oxidation are as followings. -Feasible pH was in the 3∼4 regardless of the kinds of iron ions, But the fluctuation of treatment efficiency with the change of pH was small - The mass ratio of H$_2$O/CODcr was used to evaluate the parameter of H$_2$O$_2$ The optimal range of this was in 0.7∼1,3 and it was observed that the ratio got higher as the quality got worse. -For iron ion, FeCl$_2$4H$_2$O turned out to be more effective for removal of color compared with was compared FeSO$_4$7H$_2$Oin. the mass ratio of Fe/H$_2$O$_2$ of 2.3∼2.8 for of FeSO$_4$7H$_2$O and 1.6∼1.8 for FeCl$_2$4H$_2$O resulted in good treatment efficiencies. 4. With adsorption process applied before fenton oxidation in order to treat the high concentration wastewater, the treatment efficiency increased by 61％ in CODcr, 55％ in color. and if the power activated carbon is injected in more than 2500mg/$\ell$, the wastewater can be treated within the effluent quality criteria.

In this study, comparison the removal efficiencies of organics, nitrogens and phosphorus from sewage using Ultrasonic apparatus were investigated. The concentration of SCODcr were respectively 16.3, 24.4, 48.8, 105.7, 260.3 mg/$\ell$ with time 0, 10, 30, 60, 120min respectively in 200W ultrasonic intensity. The concentration of SCODcr were respectively 124.4, 48.8, 73.2, 203.4, 374.2 mg/$\ell$ with time 0, 10, 30, 60, 120min respectively in 300W ultrasonic intensity. The concentration of SCODcr were respectively 24.4, 40.7, 81.4, 170.9, 439.3 mg/$\ell$ with time 0, 10, 30, 60, 120min respectively in 400W ultrasonic intensity.

This study was performed to investigate vibration generated from machines that were used at factories and construction works. Vibrations were measured at three points in a straight line based on distance from the vibration sources, and analyzed to assess the vibration levels. The average vibration level of factory machines was 65.4 dBV at 2 m, and that of construction machines was 74.0 dBV at 5m. Vibration attenuations was 4.0∼8.2 dBV by double distance. All such data were applied to gain coefficients of attenuation equations for predicting vibration level by distances from the vibration sources. Data recorded on tapes were analyzed to understand the characteristics of frequency because these characteristics are important factors to design a plan for installing the vibration-proof devices. Finally, considering results from these analysis, assessment, and prediction, the methods for reducing vibration generated from machines were discussed.

Geometric mean of airborne welding fume concentration at technical high schools was 4.80mg/㎥(N.D∼35.39mg/㎥) and the percentage of samples exceeded TLV of the Korean ministry of labor was 43.6％, Geometric mean of airborne Mn concentration was 0.06mg/㎥(N.D∼0.42mg/㎥) and the percentage of samples exceeded TLV of ACGIH was 15.4％. In case of airborne Mn concentration, there is a significant difference among schools (P＜0.05). Mn concentrations in blood of the exposed and control groups were 1.84$\mu\textrm{g}$/㎗ and 1.91$\mu\textrm{g}$/㎗, respectively. Mn concentrations in urine of the exposed and control groups were 1.36$\mu\textrm{g}$/$\ell$ and 0.57$\mu\textrm{g}$/$\ell$, respectively. In case of Mn concentrations in urine, there is a significant difference between both groups(P＜0.001) and among schools(P＜0.05). Mn concentrations in blood and urine of exposed group were not over BEIs of the Korean ministry of labor. Mn levels in blood and urine were not significantly affected by smoking, drinking and residence. There was no correlation between Mn concentration in air and blood, but there was a statistically significant correlation between Mn concentration in air and urine(r=0.323). There was no a Statistically significant correlation between Mn concentration in blood and urine.

This study was conducted to identify the proper analytical conditions regarding optical density for endotoxin analysis in the workplace using metalworking fludis. Our study found the "onset method" was more accurate than "time to Vmax" Reproducibility and accuracy analyzed by "onset method" was more greater than those by "time to Vmax""0.03"of optical density was the most appropriate analytical condition among onset method. Through this analytical condition, 0.998 of linearity was obtained and recovery rate ranged from 88％ to 105％ at endotoxin concentration below 5 EU/$m\ell$. No significant difference of endotoxins between "0.03"and "0.05" of optical density was observed from this study. Furthermore, correlation coefficients between them were statistically significant(p＜0.01). This study concluded that 0.03”or "0.05" of optical density is used to analyze endotoxin. Of these optical density value, value with higher linearity should be used to analyze endotoxin in environmental samples.

The purpose of this study was to investigate the metallothionein of acute cadmium poisoning mice as a Cadmium index. Forty male ICR mice were injected with cadmium chloride solution from 1/8LD$\sub$50/ to 1/2 LD$\sub$50/ dose. At 24 hours after exposed Cd, I examined Cd and metallothionein (MT) in tissues (liver and kidney) and fluids (whole blood and urine) and also measured low molecular proteins, N-acety1-${\beta}$-D-glucosaminidase (NAG) and ${\beta}$$\sub$2/- microglobuline (${\beta}$$\sub$2 /-MG) in urine. The concentration of Cd and MT of liver, kidney whole blood and urine were increased with dose dependent manner. Urinary Cd and urinary MT had very good significance (p＜0.01) and urinary MT had good significance with kidney Cd and NAG but not ${\beta}$$\sub$2/-MG. Conclusionally MT in urine was very correlated with kidney Cd and urine Cd. So MT maybe useful as a Cd poisoning index.

To identify and evaluate the dichlorobenzidine(DCB)-DNA adducts in liver cell and bladder epithelial cells by $^{32}$ P-postlabeling and GC/MS-SIM, we orally exposed the dichlorobenzidine (20mg/kh body wt.,/day)to male sprague-dawley rats for 14 days. Two kinds of DCB-DNA adduct were found at the same site of thin layer chromatogram of $^{32}$ P-postlabeling method in liver cells and bladder epithelial cells. In liver cells, relative adduct labeling(RAL) $\times$ 10$^{12}$ of DCB-DNA adduct A1 were 34.1$\pm$3.71 and 69.9$\pm$5.02, that of adduct A2 were 74.1$\pm$10.1 and 105.1$\pm$10.1 on 10 and 14 days after treatment, respectively. And in bladder epithelia cells, RAL $\times$ 10$^{12}$ of DCB-DNA adduct A1 were 5.92$\pm$1.60 and 15.9$\pm$1.31, that of adduct A2 were 9,81$\pm$2.81 and 22.8$\pm$1.79 on 10 and 14 days after treatment, respectively. DCB metabolites formed DNA adducts were monoacetyl-dichlorobenzidine(acDCB) and diacety1-dichlorobenzidine(di-acDCB), which was identify by gas chromatography/mass spectrometry-scan ionization mode(GC/MS-SIM), along with hydrolysis, extraction and TFA(trifluoroacetyl anhyride) derivatization with DCB-DNA adducts isolated from live cells and bladder epithelial cells. The base peak of acDCB were 252 and 294 m/z, and that of di-acDCB were 252, 294 and 336 m/z. In conclusion, the exposed DCB formed two kinds of DCB-DNA adduct, the proximate materials of that were acDCB and di-acDCB in liver and bladder epithlial cells. And the above GC/MS-SIM method was found the DCB-DNA adducts could be monitoring by gas chromatography.

Generally, inaccurate reports on environmental issues occur due to various factors. The purpose of this study was to find out a way to enhance accuracy of environmental reporting. So the reporters' career and college major had been compared to the accuracy of their articles. The by-lined environmental articles in nine dailies published in 1991 were checked. Results of this study were as follows. (1) Inaccuracy rate in environmental articles was 54.2％. Inaccuracies appeared 1.7 times per an article, while the average frequency of inaccuracies in overall articles was 0.9 time. (2) Errors in the articles consist of 65.8％ of subjective inaccuracies and 34.2％ of subjective inaccuracies. They derive from the false usage of terminology(15.8％), misquotation(14.5％), incorrect statistics(13％), exaggeration(13％), inaccurate title(7.9％), and false comparison(5％), (3) Inaccuracy rate by the type of articles was 66.7％ in columns, 60％ in feature stories, 54.5％ in-depth stories, 40.9％ in straight news, respectively. (4) Inaccuracy rate by the specific field was shown 71.4％ in environmental impacts (5) According to the result of chi-square test analysis, there were no statistically significant differences of inaccuracy rate and of subjective, and objective, and objective inaccuracies relevant to the period of reporters' career covering environmental reporting and the nature of articles, and college major.

This study evaluated advanced water treatment (AWT) system in Korea. There are currently 16 plants operating with AWT. However, no attempt has been made to evaluate AWT system. This study selected one water treatment plant with AWT (pre-ozonation ＋ BAC). Using the operation data from 1995 to 2001 and pilot study results, the post-evaluation of the AWT system has been conducted. The study found that AWT improved water qualities of organic, ammonia, and turbidity, as expected. However, the extent of the improvement was generally short of the pilot study expectations. Pre-ozonation failed to decrease coagulant consumption. The dosage increased rather than decreased. AWT was, however, successful to decrease chlorine consumption. The chlorine reduction was related to the change in raw water characteristics and AWT introduction. Pre-ozonation failed to decrease coagulant consumption. The dosage increased rather than decreased. AWT was, however, successful to decrease chlorine consumption. The chlorine reduction was related to the change in raw water characteristics and AWT introduction, Both operation of pre-ozonation and reduced ammonia loading were responsible for the reduction. AWT increased the operation cost. Maintenance, raw water, and power cost increased, while labor and chemical cost decreased. Manpower reduction resulting form automation caused the decrease of labor cost. The reduction of chlorine consumption caused the decrease of chemical cost.

Aflatoxin is a secondary fungal metabolite and is a public health hazard because it is a human carcinogenic and has many deleterious effects in men and animals. Rice is one of the better substrates for the fungus which can produce aflatoxins. This study was performed to investigate aflatoxin reduction during the cooking and processing of rice. Aflatoxin was produced by Aspergillus parasiticus ATCC 15517 on well-milled rice(Japonica type) at the level of 13.2 ppb. Cooked rice, rice cakes (baek-sol-gi, plain steamed rice bread), fermented rice (sik-hye, sweet rice beverage), and popped rice were prepared from the aflatoxin-contaminated rice. Aflatoxin content in the samples was determined by high performance liquid chromatography. The total aflatoxin level was decreased to 46.9％ in the cooked rice, 85.6％ in the rice cakes, 11.4％ in the fermented rice, and 7.6％ in the popped rice, respectively (p＜0.05). This reduction brought the level of aflatoxins down to below the Standard and Specification of Korea (10 ppb), except for the rice cakes. These results indicate that washing, steaming, fermentation, and popping of rice was helpful in reducing the aflatoxin level in the rice and the most helpful factors were high temperature & high pressure. More research is needed to understand why the preparation of rice cakes did not reduce the level of aflatoxin as much as the other cooking methods.

Because of the growing demand for protect and maintain one's health, population search for good water increase very rapid in recent. This study was performed to investigate the at 432 sites natural spring water quality in Seoul. Samples for analysis were collected form January to December in 2001. The quality of water was evaluated by analyzing fourty items of Korea drinking water criteria. The main results of this study were as follows 1. The rate of natural spring water was 26.6％ and the Total colony, E.Coli and Yersinia of the total incongruence cause was 67.9％ 2. The distribution of phisical-chemical item on the incongruence cause was Residues on evaporation 8.6％, Turbidity 4.3％, Nitrate nitrogen 2.5％, pH 2.5％ and F-1,2％ 3. The most population area of mean drinking population per one day was that man of Gangnam was 312.92 person. Next to Yangcheon Seocho Seodaemun and Dongjak was 229.6, 195.31, 190.50, 190,00 person. 4. The more person and the number of natural spring water, the more non passed drinking criteria natural spring water except for Gangnam and Gangbuk. 5. The corelationship of drinking population and results of the tests do not exist and the corelationship of results and Total colony, E.Coli, Color, Turbidity, KMNO4 consumption, Residues on evaporation, Fe, Mn, Zn and A1 are existed positive relationship.

Objectives : To estimate the correlation of blood lead level of families and environmental factors and infer its influence on blood lead levels in the Korean urban area in Seoul Korea. Methods : The study subjects comprised 499 men and 489 women from 366 families and we analyzed the blood lead level using induced coupled plasma/mass spectroscopy and had interviews. Results : The mean blood lead level of men was 3.00 $\mu\textrm{g}$/dL. The stastical analysis of this study used the tool of frequency rate and t-test between blood lead levels of families and environmental factors. Especially father's smoking and dusty workplace environment showed significancy to blood lead levels. Conclusion : There was positive relationship of blood lead level to several environmental factors. These facts show outdoor environment is more influential than home environment.

There have been few reports on the survey of pathological findings of cetaceans stranded on the coast of Japan. This is partly because of lack of the procedures and/or network of systemic sampling of fresh tissues for the pathological study of stranded marine mammals. In contrast, there are a numbers of reports on the cause of illness and death in wild, free-living cetaceans examined in other countries; the commonest cause of death was parasitic and bacterial pneumonia except for entanglement in fishing gear. Anthracosis, lung and hilar lymph nodes polluted by suspended particulate matter in the air, has been recently found in some cetaceans stranded on the coast of Japan. In addition to the data from the chemical analysis of tissues, scientific data obtained from pathological study of stranded marine mammals would be also one of the useful base for the assessment of global environment. Usefulness of metallothionein in the hepatopancreas of crabs as a biomarker of marine pollution monitoring was also discussed in this study.

In 1995 we licensed pyrolysis gas melting technology of indirect heating type (using kiln) from Siemens AG, and built its demonstration facility in 1998 at Clean-Park-East of Fukuoka City to demonstrate the technology for municipal solid waste (MSW). In 1997 we were awarded an order from Kanemura Co., Ltd. to build a pyrolysis gas melting and power generation plant, specifically for treating residue from car shredder. The latter was launched in 1998, and is currently in commercial operation. The operation of these plants have proven the following facts. (1) The system is capable for performing a stable operation with a wide variety of waste. (2) Pyrolysis is achieved steadily regardless of the variation in the quality of waste. (3) The system can be operated under low excess air ratio (1.2∼1.3). (4) The concentration of dioxins at the furnace outlet is 0.062ng-TEQ/㎥$\_$N/, and 0.002ng-TEQ/㎥$\_$N/, at the stack. (the value is corrected to dryO$_2$ 12％) (5) The purity of recovered metals exceeds 90%.

A recent survey investigated that there were over one thousand un-controlled closed landfills(1,072 sites) in Republic of Korea. Most of these landfills were constructed before 1986. Waste management act were not promulgated at that time, so they usually do not have dranage system and leachate treatment facility. Also, considerable attention has been received to landfill leachate pollution, leachate has an adverse impact on the surrounding environment such as soil, groundwater, and water supply source. According to the result of survey for closed landfill management, it was reported that 875 sites out of 1,072sites(81.6％) have no leachate treatment facility and 630 sites out of 1,072sites(58.7％) have been used for farm lands and residence. Consequently it is hard to do postclosure care continuously in most of cases and these uncontrolled landfills have contaminated farm lands and residence. The average age of these landfills are ranged mostly between 2 to 15 years. Much time and advanced technology are needed to remediate these uncontrolled landfills, therefore the survey for present status of closed landfill sites is required and suitable treatment processes should be prepared. With this point of view, We has been investigated to find out the present status of closed landfill, problems of post management and discussed plans for remediation and reuse. Remedial actions of un-controlled landfill have been carried out the many cities since 1997 upto now. Most frequently applied technology were reuse after excavation and there were several cases to capping in the surface of landfill and to construct subsurface barriers. It is considered that landfills in use have a possibility not to be controlled because of inadequate construction and improper management. Therefore remediation of uncontrolled landfills and recovery technology should be develop continuously Especially, it has been expected that resource technology of landfill gas as a energy has some advantages in controlling odors in the site area and accelerating stabilization of landfills with the energy.

Ultimate objective of industrial hygiene is the prevention of health impairment that may result from exposure to chemicals at workplaces. This implies the definition of permissible levels of exposure, that is, levels that according to the present status of knowledge are estimated to cause no adverse health effects during the lifetime of the workers, and the regular assessment of the possible health risk associated with exposure by comparing the current or the integrated exposure with the permissible exposure limits. Workers in solvent thinner-using occupation environment might be highly exposed to VOCs(volatile organic compounds) because solvent thinner has been used extensively such as painting, spraying, degreasing, coating and so on in Korea. The purpose of this study was to recognize, evaluate and propose the alternative control the VOCs from solvent thinner-using workplace.

Entrapped media with cellulous triacetate in which actived sludge was applied to induce operation factors and sewage treatment on site. The results are summarized as follows; The treatment efficiency of entrapped media is 92％, 90％ and 80％ at the size of 5mm, 7mm, and 12mm, respectively. Also, treatment efficient rate was increased by the packed amount of media in less than 30％ packed, while in more than 40％ packed that was decreased. It takes 10day to reach the steady states and it is less than the existing activated sludge method. The slopes of oxygen consumption rate are almost parallel both in the entrapped media and free sludge. When organic loading rate is less than 1.0 kg/㎥. d on site, it is achieved good removal rate independent of changes of loading rate.

Tan-Sui River Basin covers Taipei metropolitan area of 2,726 square kilometers with more than six million residents. Since 1988, Taiwan government started to plan and construct an integrated sewerage system, consisted by both separated and concentrated trunk sewers, wastewater treatment plants and ocean outfalls. This presentation will introduce the master plan and major facilities of Tan-Sui River Basin sewerage system. Other measures to protect general water quality and the environment of adjacent river basin area of Tan-Sui River and her tributaries by Taiwan EPA will be presented as well.

The purpose of this study was to evaluate a new sampling and analytical method for the determination of hexavalent chromium, Cr(VI) in mist from field plating operation. The Procedures of this new method (Shin & Paik's Method) are as the following: Airborne hexavalent chromium is collected on polyvinyl chloride (PVC) filter according to the National Institute for Occupational Safety and Health (NIOSH) Method 7600, and the filter sample is placed in a screw-capped vial and soaked with 2％ NaOH/3％ Na₂CO₃ solution immediately after sampling. The Cr(VI) sample is analyzed by ion chromatography/visible spectrophotometry (IC/VS) according to the U.S. Environmental Protection Agency (EPA) Method 218.6. The airborne Cr(VI) concentrations measured by this method were compared with those determined by three reference methods: One (NIOSH/EPA Method) consisted of sampling airborne Cr(VI) on PVC filters and storing the sample filters in screw-capped vials according to the NIOSH method, and analyzing Cr(VI) in samples using IC/VS according to the EPA method. The second method (Impinger Method/NaHCO₃) consisted of absorbing airborne Cr(VI) into 0.02 MN/sub a/Hco₃ solution in midget impinger, and analyzing the Cr(VI) in samples using IC/VS. The third method was the OSHA Method Id-215. Using these four different methods, four replicates of air samples were collected at an electroplating process and analyzed simultaneously. Two-way ANOVA and Paired t-test were used to test difference among values determined by the methods. There was no significant difference and a strong correlation (r/sup 2/=0.99) between Cr(VI) concentrations measured by the shin & Paik's Method and an impinger method (p＞0.05). However, Cr(VI) concentrations determined by Shin & Paik's Method were Significantly different form those by the NIOSH/EPA Method (p＜0.05) or the OSHA method (p＜0.05). The Cr(VI) concentrations of Shin & Paik's Method were Significantly higher than those of the NIOSH/EPA Method or the OSHA method. We concluded that the Shin & Paik's Method could prevent Cr(VI) losses caused by reduction and give more reliable results of airborne Cr(VI) concentrations in work environments.