Seasonal variation in airborne endotoxin levels in indoor environments with different micro-environmental factors in Seoul, South Korea.

This study evaluated the variation over a year in airborne endotoxin levels in the indoor environment of five university laboratories in Seoul, South Korea, and examined the micro-environmental factors that influenced endotoxin levels. These included temperature, relative humidity, CO2, CO, illumination, and wind velocity. A total of 174 air samples were collected and analyzed using the kinetic limulus amebocyte lysate assay. Endotoxin levels ranged from <0.001 to 8.90EU/m(3), with an overall geometric mean of 0.240EU/m(3). Endotoxin levels showed significantly negative correlation with temperature (r=-0.529, p<0.001), CO2 (r=-0.213, p<0.001) and illumination (r=-0.538, p<0.001). Endotoxin levels tended to be higher in winter. Endotoxin levels in laboratories with rabbits were significantly higher than those of laboratories with mice. Multivariate regression analysis showed that the environmental factors affecting endotoxin levels were temperature (coefficient=-0.388, p<0.001) and illumination (coefficient=-0.370, p<0.001). Strategies aimed at reducing airborne endotoxin levels in the indoor environments may be most effective if they focus on illumination.

Hearing among male firefighters: a comparison with hearing data from screened and unscreened male population.

We investigated whether hearing loss is associated with firefighting. We conducted cross-sectional study comparing hearing threshold levels (HTLs) of 912 male firefighters with two hearing databases obtained from an otologically normal male Korean population (KONP) and a non-industrial noise-exposed male Korean population (KNINEP), considering age and the main roles of firefighters. Firefighters' age-adjusted HTLs were significantly worse than those of KONP (prevalence ratio (PR)=5.29, P<0.001)but not different from those of KNINEP (PR=0.99, P=0.550). Rescuers (PR=1.005, P<0.001) had worse hearing than the KNINEP after age adjustment. Comparison of firefighters' HTLs (50th and 90th percentiles) with those of KONP and KNINEP by age and frequency showed that firefighters' HTLs had significant increases (poorer hearing) across most age groups and frequencies compared with KONP. Compared with KNINEP, firefighters' HTLs were worse in the younger age groups (<45 years) but not different in the older age groups (>45 years). In conclusion, the hearing thresholds of younger firefighters and rescuers were worse than expected by normal aging alone. Future research should include longitudinal studies to consider variable risk factors, such as military service, smoking, and so on.

Analysis of variation in total airborne bacteria concentration to assess the performance of biological safety cabinets in microbial laboratories.

BACKGROUND: The purpose of this study was to compare the concentration of total airborne bacteria (TAB) in biosafety cabinets (BSCs) at universities and hospital microbial laboratories to assess the performance of BSCs. METHODS: TAB was determined by using the single-stage Anderson sampler (BioStage Viable Cascade Impactor). The samples were obtained three times (with the BSC turned off and the shield open; with the BSC turned off and the shield closed; and with the BSC tuned on and operating) from the areas in front of 11 BSCs. RESULTS: TAB concentrations of accredited and nonaccredited BSCs were determined. No significant differences were observed in the TAB concentrations of the accredited BSCs and the nonaccredited BSCs for the areas outside the BSCs in the laboratories (p > 0.05). TAB concentrations for the BSCs sampled with the shield open and the instrument turned off showed differences based on the sampling site outside the BSC in each laboratory. CONCLUSION: These results imply that TAB concentration is not altered by the performance of the BSCs or TAB itself and/or concentration of TAB outside the BSC is not a good index of BSC performance.

Outdoor (1→3)-ß-D-glucan levels and related climatic factors.

OBJECTIVES: To evaluate the monthly variation in the airborne (1→3)-ß-D-glucan level throughout one year and its relationship with climatic factors (temperature, relative humidity, wind speed, hours of daylight, cloud cover, and pollen counts). METHODS: A total of 106 samples were collected using a two-stage cyclone sampler at five outdoor sampling locations (on top of 5 university buildings). The kinetic limulus amebocyte lysate assay was used to obtain (1→3)-ß-D-glucan levels. RESULTS: Airborne (1→3)-ß-D-glucan levels were significantly higher in the spring, particularly in April, and temperature was significantly related to (1→3)-ß-D-glucan levels (r =0.339, p<0.05). CONCLUSIONS: (1→3)-ß-D-glucan levels may be highest in the spring, and outdoor temperature may influence (1→3)-ß-D-glucan levels.

Assessment of noise measurements made with a continuous monitoring in time.

The World Health Organization has stated that hearing loss is one of the top 10 health problems worldwide and that noise-induced hearing loss is the leading occupational disease. This work evaluated the noise exposure levels of several job categories for 24-h periods over 7 days to determine the contribution of each microenvironment to total noise exposure. The noise exposure levels of 47 individuals were continuously measured using personal noise dosimeters in metropolitan Seoul, Korea. Participants ranged in age from 20 to 50 yr and represented eight occupational groups. Participants were asked to attach the noise dosimeters and complete a time-activity diary 24 h a day for 7 days. The average Leq 24 h,w among these individuals was 74 dBA, which ranged from 64 to 96 dBA. The average Leq 24 h,w was highest for Korean traditional music apprentices, followed by heavy equipment operators, firefighters, service workers, office workers, industrial hygienists, graduate and undergraduate students, and housewives (89, 77, 76, 76, 75, 71, 71, and 71 dBA, respectively, p < 0.001). 38 (80.9%) were exposed to noise levels greater than 70 dBA, which corresponds to the World Health Organization's exposure limit.

Characterization of the monthly variation in (1 → 3)-ß-D-glucan concentrations in university laboratories.

We characterize the monthly variation in (1 → 3)-ß-D-glucan concentration measured over the course of 1 year, and we evaluate the characteristics of size selection using a two-stage cyclone sampler. The (1 → 3)-ß-D-glucan concentrations were measured in four bio-related laboratories. A total of 156 samples were collected using a new two-stage cyclone sampler. Analysis of (1 → 3)-ß-D-glucan was performed using the kinetic Limulus amebocyte lysate assay. The study showed that airborne (1 → 3)-ß-D-glucan concentrations were significantly higher in laboratory D (mean ± SD 1,105 ± 1,893 pg/m(3)) and in the spring (5,458 pg/m(3)). The highest concentration of (1 → 3)-ß-D-glucan occurred in the spring, particularly in May.

Workplace field testing of the pressure drop of particulate respirators using welding fumes.

In a previous study, we concluded that respirator testing with a sodium chloride aerosol gave a conservative estimate of filter penetration for welding fume aerosols. A rapid increase in the pressure drop (PD) of some respirators was observed as fumes accumulated on the filters. The present study evaluated particulate respirator PD based on workplace field tests. A field PD tester was designed and validated using the TSI 8130 Automatic Filter Tester, designed in compliance with National Institute for Occupational and Safety and Health regulation 42 CFR part 84. Three models (two replaceable dual-type filters and one replaceable single-type filter) were evaluated against CO(2) gas arc welding on mild steel in confined booths in the workplace. Field tests were performed under four airborne concentrations (27.5, 15.4, 7.9, and 2.1 mg m(-3)). The mass concentration was measured by the gravimetric method, and number concentration was monitored using P-Trak (Model 8525, TSI, USA). Additionally, photos and scanning electron microscopy-energy dispersive X-ray spectroscopy were used to visualize and analyze the composition of welding fumes trapped in the filters. The field PD tester showed no significant difference compared with the TSI tester. There was no significant difference in the initial PD between laboratory and field results. The PD increased as a function of fume load on the respirator filters for all tested models. The increasing PD trend differed by models, and PD increased rapidly at high concentrations because greater amount of fumes accumulated on the filters in a given time. The increase in PD as a function of fume load on the filters showed a similar pattern as fume load varied for a particular model, but different patterns were observed for different models. Images and elemental analyses of fumes trapped on the respirator filters showed that most welding fumes were trapped within the first layer, outer web cover, and second layer, in order, while no fumes were observed beneath the fourth layer of the tested respirators. The current findings contribute substantially to our understanding of respirator PD in the presence of welding fumes.

Residential environmental risk factors for childhood asthma prevalence in metropolitan and semirural cities in Korea.

To identify the association between residential environmental risk factors and the prevalence of childhood asthma, the authors surveyed the prevalence of asthma, the residential environmental risk factors of 1819 elementary school students, and air pollution in metropolitan (Seongbuk), and semirural (Andong) areas. Although there was no significant difference in the prevalence of self-reported asthma (SA) between the 2 geographic areas (12.8% vs 13.6%), the prevalence of physician-diagnosed asthma (PDA) in Andong (15.0%) was significantly higher than that in Seongbuk (6.8%). After adjusting for confounding factors, logistic regression suggested that there were significant differences in size of the house (adjusted odds ratio [aOR] = 1.82), medical insurance (aOR = 2.59), and number of residents in the household (aOR = 1.54) between the SA and non-SA groups. There was a significant difference in the area of residence (aOR = 2.12) between the PDA and non-PDA groups. In conclusion, residential environmental risk factors and the area of residence affect the prevalence of childhood asthma.

Comparison of endotoxin levels and gram-negative bacteria under different conditions in microbial laboratories and a biowaste site.

In this study, we assessed airborne endotoxin levels in university laboratories, hospital diagnostic laboratories, and a biowaste site. We also investigated indoor and outdoor sampling, sampling site, type of ventilation system, presence of open biowaste boxes, weather, and detection of Gram-negative bacteria (GNB). A total of 69 air samples were collected from 11 facilities in three institutions. Average total airborne endotoxin levels ranged from <0.01 to 10.02 EU m(-3), with an overall mean of 1.03 EU m(-3). Endotoxin levels were high in window-ventilated facilities, in facilities in which GNB were detected; levels were also high when it was rainy (all ps<0.05). Endotoxin levels were significantly correlated with humidity (r=0.70, p<0.01). The presence of HVAC; humidity; and the presence of open biowaste boxes affect endotoxin levels in laboratories.

Comparison of pressure drop and filtration efficiency of particulate respirators using welding fumes and sodium chloride.

Respirators are used to help reduce exposure to a variety of contaminants in workplaces. Test aerosols used for certification of particulate respirators (PRs) include sodium chloride (NaCl), dioctyl phthalate, and paraffin oil. These aerosols are generally assumed to be worst case surrogates for aerosols found in the workplace. No data have been published to date on the performance of PRs with welding fumes, a hazardous aerosol that exists in real workplace settings. The aim of this study was to compare the performance of respirators and filters against a NaCl aerosol and a welding fume aerosol and determine whether or not a correlation between the two could be made. Fifteen commercial PRs and filters (seven filtering facepiece, two replaceable single-type filters, and six replaceable dual-type filters) were chosen for investigation. Four of the filtering facepiece respirators, one of the single-type filters, and all of the dual-type filters contained carbon to help reduce exposure to ozone and other vapors generated during the welding process. For the NaCl test, a modified National Institute for Occupational Safety and Health protocol was adopted for use with the TSI Model 8130 automated filter tester. For the welding fume test, welding fumes from mild steel flux-cored arcs were generated and measured with a SIBATA filter tester (AP-634A, Japan) and a manometer in the upstream and downstream sections of the test chamber. Size distributions of the two aerosols were measured using a scanning mobility particle sizer. Penetration and pressure drop were measured over a period of aerosol loading onto the respirator or filter. Photos and scanning electron microscope images of clean and exposed respirators were taken. The count median diameter (CMD) and mass median diameter (MMD) for the NaCl aerosol were smaller than the welding fumes (CMD: 74 versus 216 nm; MMD: 198 versus 528 nm, respectively). Initial penetration and peak penetration were higher with the NaCl aerosol. However, pressure drop increased much more rapidly in the welding fume test than the NaCl aerosol test. The data and images clearly show differences in performance trends between respirator models. Therefore, general correlations between NaCl and weld fume data could not be made. These findings suggest that respirators certified with a surrogate test aerosol such as NaCl are appropriate for filtering welding fume (based on penetration). However, some respirators may have a more rapid increase in pressure drop from the welding fume accumulating on the filter. Therefore, welders will need to choose which models are easier to breathe through for the duration of their use and replace respirators or filters according to the user instructions and local regulations.

An assessment of dust, endotoxin, and microorganism exposure during waste collection and sorting.

This study was conducted to assess inhalation exposure to dust, endotoxin, and microorganisms (including viable bacteria, Gram-negative bacteria [GNB], and fungi) during waste collection and sorting; to identify factors affecting this exposure; and to estimate the gastrointestinal exposure to microorganisms. A total of 48 or 49 workers involved in collecting and sorting waste from households or the street were studied. Each worker carried two personal samplers in which filters were placed in the breathing zone for estimation of inhalation exposure. To assess the possibility of gastrointestinal exposure, microorganisms on the workers' faces were collected before and after work and compared with those collected from office workers. Inhalation exposure levels were categorized according to job title, waste type handled, and working conditions and were compared using analysis of variance. Multiple regression models were developed to identify those factors that substantially affected inhalation exposure. The average exposure level to total dust was 0.9 mg/m3 (range = 0.05 to 4.51 mg/m3), and the average exposure to endotoxin was 1123 EU/m3. The average respective exposure levels to bacteria, GNB, and fungi each exceeded 10(4) colony forming units (CFU)/m3. The multiple regression models found several factors that significantly explained the variation in levels of inhalation exposure to endotoxin and microorganisms; namely, sex (dust, bacteria, and GNB), job title (GNB and fungi), collection day (dust, bacteria, and GNB), temperature (endotoxin and GNB), humidity (endotoxin and fungi), and region (endotoxin) were significantly associated with exposure to these agents. In addition, the workers' faces were highly contaminated with microorganisms. In conclusion, inhalation exposure to endotoxin and microorganisms was high during waste collection and sorting, which may place workers at risk of developing various health problems, including respiratory complaints.

Airborne bacteria concentrations and related factors at university laboratories, hospital diagnostic laboratories and a biowaste site.

AIMS: To evaluate concentrations of airborne bacteria in university laboratories, hospital diagnostic laboratories, and a biowaste site in Seoul, Korea. To measure total airborne bacteria (TAB), the authors assessed sampling site, type of ventilation system, weather and detection of Gram-negative bacteria (GNB), indoors and outdoors. METHOD: An Andersen one-stage sampler (Quick Take 30; SKC Inc) was used to sample air at a flow rate of 28.3 l/min for 5 min on nutrient medium in Petri dishes located on the impactor. A total of 236 samples (TAB, 109 indoor and nine outdoor; GNB, 109 indoor and nine outdoor) were collected three times in each spot from the 11 facilities to compare airborne bacteria concentrations. RESULTS: TAB concentrations ranged from undetectable to 3451 CFU/m³ (mean 384 CFU/m³), and GNB concentrations from undetectable to 394 CFU/m³ (mean 17 CFU/m³). TAB concentrations were high in window-ventilated facilities and facilities in which GNB were detected; concentrations were also high when it was rainy (all p values <0.05). TAB concentrations correlated significantly with GNB (r=0.548, p<0.01), number of bacteria species (r=0.351, p<0.01) and temperature (r=0.297, p<0.01). The presence of heating, ventilating, and air conditioning (HVAC), the number of TAB species and the detection of GNB affect TAB concentrations in laboratories. CONCLUSIONS: It is recommended that special attention be given to regular control of indoor environments to improve the air quality of university and hospital laboratories.

Phototoxicity of CdSe/ZnSe quantum dots with surface coatings of 3-mercaptopropionic acid or tri-n-octylphosphine oxide/gum arabic in Daphnia magna under environmentally relevant UV-B light.

The potential ecotoxicological consequences about semiconductor crystal nanoparticles (NPs) are a growing concern. However, our understanding of the mechanism of toxicity in NPs is very limited, especially under varying environmental conditions such as ultraviolet (UV) light. We performed an in vivo study employing Daphnia magna to evaluate the mechanism involved in toxicity of cadmium selenide/zinc selenide quantum dots (QDs) with two different organic coatings under an environmental level of UV-B light. We used QDs with mercaptopropionic acid (MPA) and tri-n-octylphosphine oxide/gum arabic (GA) and measured their toxicities under an environmental level of UV-B light. Whole-body reactive oxygen species (ROS) generation and mRNA expression level biomarkers, as well as acute toxicity, were measured in D. magna. With UV-B light, both cadmium (Cd) and GA-QD became more toxic in daphnids. The levels of small Cd molecules (<10kDa cutoff) increased for GA-QD under UV-B; however, the observed acute lethal toxicity could not be explained by the measured Cd level. Under UV-B light, both Cd and GA-QD generated more ROS. In addition, the expression pattern of mRNAs specific to Cd exposure was not observed from GA-QD with or without UV-B light. These observations suggest that the phototoxicity of QDs may be explained not only by Cd release from the QD core but also by stability of surface coating characteristics and other potential causes such as ROS generation.

Vaporization and Conversion of Ethanolamines used in Metalworking Operations.

OBJECTIVES: This study examined how ethanolamines (EAs) with the same functional alcohol group (HOCH(2)CH(2)), such as mono-EA (MEA), di-EA (DEA), and tri-EA (TEA), in water-based metalworking fluids (wbMWFs) are vaporized, condensed, and transformed by heat generated during metalworking. METHODS: Two types of experimental apparatus were manufactured to achieve these objectives. RESULTS: Vaporization tests using a water bath showed that the vaporization rate increased markedly from 0.19 mg/m(2)·min at 23.5℃ to 8.04 mg/m(2)·min at 60℃. Chamber tests with a heat bulb revealed that "spiked" MEA was fully recovered, while only 13.32% of DEA and no TEA were recovered. Interestingly, non-spiked types of EAs were detected, indicating that heat could convert EAs with more alcohol groups (TEA or DEA) into other EAs with fewer group(s) (DEA or MEA). The EA composition in fresh fluid was 4% DEA, 66% TEA, and 30% MEA, and in used fluids (n = 5) was 12.4% DEA, 68% TEA, and 23% MEA. Conversion from TEA into DEA may therefore contribute to the DEA increment. Airborne TEA was not detected in 13 samples taken from the central coolant system and near a conveyor belt where no machining work was performed. The DEA concentration was 0.45 mg/m(3) in the only two samples from those locations. In contrast, airborne MEA was found in all samples (n = 53) regardless of the operation type. CONCLUSION: MEAs easily evaporated even when MWFs were applied, cleaned, refilled, and when they were in fluid storage tanks without any metalworking being performed. The conversion of TEA to DEA and MEA was found in the machining operations.

Whole blood and red blood cell manganese reflected signal intensities of T1-weighted magnetic resonance images better than plasma manganese in liver cirrhotics.

We examined whole blood (MnB), red blood cell (MnRBC), plasma (MnP) and urinary Mn (MnU) concentrations in 22 liver cirrhotics and 10 healthy controls to evaluate Mn concentration in which a fraction of biological samples best reflects pallidal signal intensities (pallidal index; PI) on T1-weighted magnetic resonance images (MRI) in liver cirrhotics. Increased signal intensity in the globus pallidus was observed in 18 (81.8%) of the 22 patients with liver cirrhosis. In a transplanted patient, increased pallidal signals also resolved as his liver function tests normalized after liver transplantation. There were significant correlations between MnB/MnRBC and PI (rho=0.529, rho=0.573, respectively) in liver cirrhotics, although no significant correlation was observed between MnP/MnU and PI. According to a multiple linear regression, MnB and MnRBC reflected the signal intensities of T1-weighted MRI better than MnP or MnU.

Blood manganese concentration is elevated in iron deficiency anemia patients, whereas globus pallidus signal intensity is minimally affected.

OBJECTIVES: To determine whether blood manganese (Mn) concentration is elevated in patients with iron deficiency anemia (IDA), and whether this affects signal intensities in the globus pallidus. METHODS: Twenty-seven patients with IDA and 10 control subjects were tested for blood Mn, and brain magnetic resonance images (MRI) were also examined. Seventeen of the 27 patients were followed-up after iron therapy. RESULTS: IDA patients had a mean blood Mn concentration of 2.05 +/- 0.44 microg/dl, which was higher than controls. The mean pallidal index (PI) of anemic patients was not different from that of controls. There was a correlation between log blood Mn and PI (rho = 0.384, P = 0.048; n = 27) in IDA patients. None of the patients showed increased signals in the globus pallidus in T1-weighted MRI. Blood Mn levels decreased and hemoglobin levels increased after iron therapy (P < 0.05). CONCLUSION: Although blood Mn is elevated in IDA patients, there is no increase in globus pallidus MRI signal intensity. These findings stand in contrast to those of our other studies showing patients with chronic liver disease or occupational Mn exposure have elevated signal intensities remarkably.

Loss of straight metalworking fluid samples from evaporation during sampling and desiccation.

Straight metalworking fluids (MWFs) were used to evaluate the potential for the loss of MWF mass from filters. Two methods were used to study the stability of MWF mass on filter media. The first was to spike known amounts of MWF onto polyvinyl chloride (PVC) filters, store the filters over silica gel desiccant, and take repeated gravimetric measurements of the filters at intervals of 1, 2, and 3 days. An MWF aerosol mist was generated in a test chamber and collected on PVC filters for the second experimental method. Additional clean air was drawn through a subset of filters (range 0.02-0.48 m(3)), which were then stored over silica gel prior to weighing. Losses due to desiccation were found in filters that had not been exposed to airflow, as well as for filters after aspiration. The losses occurring in spiked filters (range of mean 2.6-15.2%) were higher than those in collected filters (range 0.7-8.1%). The MWF aerosol mass collected on PVC filters decreased with the increasing volume of clean air passing through the filter. In a multiple regression model, to predict the loss of collected MWF due to desiccation, loading mass, fresh MWF, and air passing time of 10 min were significant predictors (p=.0001, R(2)=.374). In particular, only air passage of 10 min was significantly higher (2.13%) than the reference air passage (p=.0054). The investigators concluded that MWF aerosol collected on PVC filters may be lost to evaporation under conditions typical of shipment, storage, and desiccation of sample filters, and with airflow through the filter.

Calcification mimicking manganese-induced increased signal intensities in T1-weighted MR images in a patient taking herbal medicine: case report.

Characteristic high signal intensities confined to the globus pallidus on T1-weighted magnetic resonance image (MRI) can be observed in manganese (Mn)-exposed workers, however, these high signals should be differentiated from those due to other causes such as fat, hemoglobin breakdown products, melanoma, neurofibromatosis, and calcification. A 39-year-old woman was admitted with mutism and involuntary movements which had developed the day before. She had ingested two packs of liquid herbal medicine containing 0.53 mg of Mn daily for 4 months prior to visiting our hospital. Her MRI showed high signals, confined mainly to the globus pallidus on T1-weighted images. Follow-up brain MRI at an interval of 11 months showed no interval change. Brain computed tomography (CT) at the time of the second MRI showed symmetric calcification on both globus pallidus. Blood levels of liver function tests, calcium, phosphorus, and parathyroid hormone were within normal ranges. The increased signals, which were first presumed to be induced by Mn, were concluded to be due to calcification based on the following reasons. First, follow-up brain MRI at an interval of 11 months did not show any interval change. Second, the ingested amount of 1.06 mg Mn daily for 4 months is even less than that added to mineral supplements for adults. Third, Mn-induced high signals in T1-weighted MRI do not show any abnormal findings in brain CT. The present case report suggests that brain CT should be performed to rule out symmetric calcification on basal ganglia in patients showing increased signals in T1-weighted MRI, but who do not have a significant exposure history to Mn. The present report also showed that the amount of 1.06 mg Mn daily ingested for 4 months did not cause the high signal in brain MRI.

Whole blood manganese correlates with high signal intensities on T1-weighted MRI in patients with liver cirrhosis.

We examined whole blood (MnB), plasma (MnP) and urinary Mn (MnU) concentrations in 33 cirrhotics and 11 healthy controls to clarify: (1) whether, in chronic liver diseases, MnB or MnP reflects pallidal signal intensities in magnetic resonance imaging (MRI); and (2) which factors in chronic liver diseases correlate with pallidal signal intensities in T1-weighted MRI. Increased signal intensity in the pallidum was observed in 27 (81.8%) of 33 patients with liver cirrhosis in T1-weighted MRI. There was a significant correlation between MnB and pallidal index (PI) (gamma = 0.559, P < 0.01) in the patients. However, no significant correlation was observed between MnP and PI (gamma = 0.353, P > 0.05). According to a multiple linear regression, MnB reflected the signal intensities of T1-weighted MRI better than MnP or MnU. Child/Pugh score and total bilirubin level also correlated with PI. However, the hemoglobin level did not correlate with PI significantly.

Fume generation and content of total chromium and hexavalent chromium in flux-cored arc welding.

This study was performed to investigate the fume generation rates (FGRs) and the concentrations of total chromium and hexavalent chromium when stainless steel was welded using flux-cored arc welding (FCAW) with CO2 gas. FGRs and concentrations of total chromium and hexavalent chromium were quantified using a method recommended by the American Welding Society, inductively coupled plasma-atomic emission spectroscopy (NIOSH Method 7300) and ion chromatography (modified NIOSH Method 7604), respectively. The amount of total fume generated was significantly related to the level of input power. The ranges of FGR were 189-344, 389-698 and 682-1157 mg/min at low, optimal and high input power, respectively. It was found that the FGRs increased with input power by an exponent of 1.19, and increased with current by an exponent of 1.75. The ranges of total chromium fume generation rate (FGRCr) were 3.83-8.27, 12.75-37.25 and 38.79-76.46 mg/min at low, optimal and high input power, respectively. The ranges of hexavalent chromium fume generation rate (FGRCr6+) were 0.46-2.89, 0.76-6.28 and 1.70-11.21 mg/min at low, optimal and high input power, respectively. Thus, hexavalent chromium, which is known to be a carcinogen, generated 1.9 (1.0-2.7) times and 3.7 (2.4-5.0) times as the input power increased from low to optimal and low to high, respectively. As a function of input power, the concentration of total chromium in the fume increased from 1.57-2.65 to 5.45-8.13% while the concentration of hexavalent chromium ranged from 0.15 to 1.08%. The soluble fraction of hexavalent chromium produced by FCAW was approximately 80-90% of total hexavalent chromium. The concentration of total chromium and the solubility of hexavalent chromium were similar to those reported from other studies of shielded metal arc welding fumes, and the concentration of hexavalent chromium was similar to that obtained for metal inert gas-welding fumes.