• Journal of Environmental Health Sciences
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• v.45 no.3
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• pp.258-266
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• 2019

Objectives: In this study, blood lead was analyzed using graphite furnace atomic absorption spectrometry (GF-AAs) and inductively coupled plasma mass spectrometry (ICP-MS). We tried to examine the difference and consistency of the analytical values and the applicability of the analytical method. Methods: We selected 57 people who agreed to participate in this study. After confirming the linearity of the calibration standard curves in GF-AAs and ICP-MS, the concentrations of lead in quality control material and samples were measured, and the degree of agreement was compared. Results: The detection limit of the ICP-MS was lower than that of GF-AAs. The coefficient of variation of reference materials was shown to be stable in the ICP-MS and GF-AAs. When the correspondence between the two equipments was verified by bias of the analysis values, a concordance was shown, and approximately 98% of the ideal reference lines were present within ${\pm}40%$ of the deflection. Conclusion: GF-AAs showed high sensitivity to single heavy metal analysis, but it took much time and showed higher detection limit than ICP-MS. Therefore, it would be considered necessary to switch to ICP-MS analysis method, considering that the level of lead exposure is gradually decreasing.

• Journal of Environmental Science International
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• v.8 no.4
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• pp.457-464
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• 1999

To develop managing guidance of occupational noise exposure for metal working facility, we have studied about drafting contour map of noise exposure, methods of noise assessment and actual calculation method of time weighted noise exposure. Therefore we have suggested that contour maps of noisy workplace are very important for controlling metal working fluid facility and two kinds of noise assessment method, so called, personal andstatic exposure are necessary to avoid argument between workers and managing group. Finally we would like recommend that the Korean specification of noise exposure should be modified to protect ONIHL(oocupational noise induced hearing loss).

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.23.1-23.14
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• 2023

Background: Exposure to heavy metals is a public health concern worldwide. Previous studies on the association between heavy metal exposure and neurobehavioral functions in children have focused on single exposures and clinical manifestations. However, the present study evaluated the effects of heavy metal complex exposure on subclinical neurobehavioral function using a Korean Computerized Neurobehavior Test (KCNT). Methods: Urinary mercury, lead, cadmium analyses as well as symbol digit substitution (SDS) and choice reaction time (CRT) tests of the KCNT were conducted in children aged between 10 and 12 years. Reaction time and urinary heavy metal levels were analyzed using partial correlation, linear regression, Bayesian kernel machine regression (BKMR), the weighted quantile sum (WQS) regression and quantile G-computation analysis. Results: Participants of 203 SDS tests and 198 CRT tests were analyzed, excluding poor cooperation and inappropriate urine sample. Partial correlation analysis revealed no association between neurobehavioral function and exposure to individual heavy metals. The result of multiple linear regression shows significant positive association between urinary lead, mercury, and CRT. BMKR, WQS regression and quantile G-computation analysis showed a statistically significant positive association between complex urinary heavy metal concentrations, especially lead and mercury, and reaction time. Conclusions: Assuming complex exposures, urinary heavy metal concentrations showed a statistically significant positive association with CRT. These results suggest that heavy metal complex exposure during childhood should be evaluated and managed strictly.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.2
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• pp.87-98
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• 2020

Objective: The purpose of this study was to propose a sequential procedure for the simultaneous analysis of soluble and insoluble metal compounds. Methods: Methods for sampling and analyzing metal compounds such as ISO standards, NIOSH methods, HSE methods, and OSHA methods were reviewed. Results: Some metals have different OELs depending on the solubility of the compound. Therefore, we should take into account these characteristics and perform an exposure assessment. Soluble metal compounds are first extracted from the filter, and then the filter is digested by acids to analyze residual insoluble components. The extraction of soluble compounds can be completed by agitation for about 60 minutes with a leach solution (water) in a water bath at 37℃. For the analysis of insoluble compounds, the sample filter and the filtration filter remaining after the extraction of the soluble compounds are analyzed. This allows simultaneous determination of soluble and insoluble metal compounds. For hexavalent chromium compounds, soluble hexavalent chromium can first be extracted from the filter by using sulfate buffer. The insoluble hexavalent chromium remaining in the filter can then be extracted using carbonate buffer. Conclusion: Workers are often exposed to many hazardous substances with different exposure limits at industrial sites. The OELs for compounds of the same metal can be set differently depending on solubility. This study can help evaluate a worker's exposure to metal compounds by suggesting methods for the simultaneous determination of soluble and insoluble metal compounds.

• Safety and Health at Work
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• v.10 no.4
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• pp.518-526
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• 2019

Background: Additive manufacturing (AM) is a rapidly expanding new technology involving challenges to occupational health. Here, metal exposure in an AM facility with large-scale metallic component production was investigated during two consecutive years with preventive actions in between. Methods: Gravimetric analyzes measured airborne particle concentrations, and filters were analyzed for metal content. In addition, concentrations of airborne particles <300 nm were investigated. Particles from recycled powder were characterized. Biomonitoring of urine and dermal contamination among AM operators, office personnel, and welders was performed. Results: Total and inhalable dust levels were almost all below occupational exposure limits, but inductively coupled plasma mass spectrometry showed that AM operators had a significant increase in cobalt exposure compared with welders. Airborne particle concentrations (<300 nm) showed transient peaks in the AM facility but were lower than those of the welding facility. Particle characterization of recycled powder showed fragmentation and condensates enriched in volatile metals. Biomonitoring showed a nonsignificant increase in the level of metals in urine in AM operators. Dermal cobalt and a trend for increasing urine metals during Workweek Year 1, but not in Year 2, indicated reduced exposure after preventive actions. Conclusion: Gravimetric analyses showed low total and inhalable dust exposure in AM operators. However, transient emission of smaller particles constitutes exposure risks. Preventive actions implemented by the company reduced the workers' metal exposure despite unchanged emissions of particles, indicating a need for careful design and regulation of the AM environments. It also emphasizes the need for relevant exposure markers and biomonitoring of health risks.

• Journal of Environmental Health Sciences
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• v.40 no.4
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• pp.279-293
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• 2014

Objectives: Children are more susceptible to heavy metal toxicity than adults. The purpose of this study was to evaluate heavy metal concentrations in the blood of Korean preschoolers and investigate the association between metals in blood and related factors. Methods: A total of 512 subjects from 36 to 83 months of age were sampled. A questionnaire survey was performed and the levels of lead, mercury and cadmium were measured in the blood samples of all subjects. Their parents were interviewed in order to obtain information on basic characteristics, dietary patterns, socio-economic factors, and indoor/outdoor environment of the preschoolers. Multiple linear regression was used to analyze the association between the above factors and lead, mercury or cadmium concentrations. Results: The geometric mean concentrations of lead, mercury and cadmium in the blood were $1.45{\pm}1.58{\mu}g/dL$, $2.14{\pm}1.74{\mu}g/dL$ and $0.23{\pm}1.91{\mu}g/dL$, respectively. Results from multiple linear regression analysis showed that blood lead levels were associated with birth weight and paternal smoking status. Daily mercury intake from food and maternal education were also shown to influence mercury concentrations in blood. Also, blood cadmium concentrations were associated with maternal age and having a bus garage near the place of residence. Conclusion: This study suggests that smoking status, dietary patterns and the environmental status near the residence should be considered as important factors for preventable sources of heavy metal exposure in preschoolers.

• Korean Journal of Ecology and Environment
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• v.40 no.4
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• pp.489-494
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• 2007

Transcriptional modulation of metallothionein (MT) during acute metal exposures (cadmium, copper or zinc) was examined in fry of Hemibarbus mylodon, a threatened fish species in Korean peninsula. Viability of H. mylodon fry was most affected by copper exposure (up to 79% of mortality at 1 ppm for 48 hours) and considerably by cadmium exposure (21 to 54% of mortality). On the other hand, Zn showed the least adverse effect on the viability (0 to 13% of mortality) of this species. Based on the semi-quantitative RT-PCR analysis, the stimulation of MT mRNA in response to metal exposures followed generally in a dose-dependent fashion where cadmium was the most potent inducer for the induction of MT transcripts in fry (up to more than 5-fold) while the lowest response was observed in zinc-exposed group (2-fold at maximum). From the exposure using environmentally realistic doses of cadmium (0 to 0.05 ppm for 24 hours), MT expression at mRNA level was also sensitively modulated toward upregulation up to more than 3-fold as relative to non-exposed control. Results from the present study would be a good basis for understanding the adaptive capacity and stress physiology of this endangered fish species during metal pollution.

• Journal of the Korean Vacuum Society
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• v.6 no.1
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• pp.1-8
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• 1997

The contamination structure and process on SUS 316 under various exposure conditions were investigated using x-ray photoelectron spectroscopy. The metal-oxide, metal-H-oxides, CO, COH, and $C_xH_y$ are the main components of contaminants on the SUS surface. The compositional profiles of the contaminants are shown to be $C_xH_y$/CO(COH)/metal-oxide on SUS. The contamination proceeds in two steps. The oxidation of the metallic constituents followed by adsorption of hydrocarbons. Under UHV conditions the contamination is mainly due to the oxidation, and, as the exposure time increases, the oxidation continues. In HV or higher pressure, most of the oxides are formed almost immediately after exposure and as the exposure time increases the contamination of hydrocarbons continues to grow. For the SUS sample exposed to atmosphere, the metal oxide is distributed deep inside the surface with an exponentially decreasing concentration, and its thickness is nearly in the order of photoelectron mean free path. It is also seen that the Fe oxide is segregated over Cr oxide in the highly oxidized samples.

• Journal of Environmental Health Sciences
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• v.44 no.5
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• pp.491-501
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• 2018

Objectives: The aims of this study were to compare concentrations and the correspondence of human blood cadmium by using graphite furnace atomic absorption spectrometry (GF-AAS) and inductively coupled plasma-mass spectrometry (ICP-MS), which are representative methods of heavy metal analysis. Methods: We randomly selected 79 people who agreed to participate in the research project. After confirming the linearity of the calibration curves for GF-AAS and ICP-MS, the concentrations of cadmium in a quality control standard material and blood samples were measured, and the correlation and the degree of agreement were compared. Results: The detection limit of ICP-MS (IDL: $0.000{\mu}g/L$, MDL: $0.06{\mu}g/L$) was lower than that of GF-AAS (IDL: $0.085{\mu}g/L$, MDL: $0.327{\mu}g/L$). The coefficient of variation of the quality control standard material showed stable values for both ICP-MS (clinchek-1: 5.35%, clinchek-2: 6.22%) and GF-AAS (clinchek-1: 7.92%, clinchek-2: 5.22%). Recovery was relatively high for both ICP-MS (clinchek-1: 95.1%, clinchek-2: 92.8%) and GF-AAS (clinchek-1: 91.4%, clinchek-2: 98.8%), with more than 90%. The geometric mean, median, and percentile of blood samples were all similar. The agreement of the two instruments compared with the bias of the analytical values found that about 81% of the analytical values were within ${\pm}30%$ of the deviation from the ideal reference line (y=0). As a result of the agreement limit, the value included in the confidence interval was about 94%, which shows high agreement. Conclusion: In this study, we confirmed there was no significant difference in concentrations of a quality control standard material and blood samples. Since ICP-MS showed lower concentrations than GF-AAS at concentrations below the method detection limit of GF-AAS, it is expected that more precise results will be obtained by analyzing blood cadmium with ICP-MS.

• Fisheries and Aquatic Sciences
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• v.12 no.3
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• pp.179-184
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• 2009

Hemibarbus mylodon (Cypriniformes) is an endemic freshwater fish species in the Korean peninsula, for which urgent conservation efforts are needed. To understand their stress responses in relation to metal toxicity and thermal elevation, we performed a real-time RT-PCR-based expression assay of hepatic copper/zinc-superoxide dismutase (Cu/Zn-SOD), a key antioxidant enzyme, in response to experimental heavy metal exposure or heat treatment. The transcription of hepatic Cu/Zn-SOD was differentially modulated by acute exposure to Cu, cadmium (Cd), or Zn. Exposure to each metal at $5{\mu}M$ for 24 h revealed that Cu stimulated the mRNA expression of Cu/Zn-SOD to a greater extent than the other two heavy metals. The elevation in Cu/Zn-SOD transcripts in response to Cu exposure was dose-dependent (0.5 to $5{\mu}M$). Time course analysis of Cu/Zn-SOD expression in response to Cd exposure ($5{\mu}M$) revealed a transient pattern up to day 7. Exposure to thermal stress (an increase from 22 to $30^{\circ}C$ at a rate of $1^{\circ}C/h$ followed by $30^{\circ}C$ for 18 h) did not significantly alter SOD transcription, although heat shock protein 90 kDa (HSP90) transcription was positively correlated with an increase in temperature.