Bong-Ki Jang

A Study on the Optimal Analytical Method for the Determination of Urinary Arsenic by Hydride Generation-Atomic Absorption Spectrometry

This study was carried out to examine the optimal analytical method for determination of urinary toxic arsenic (inorganic arsenic and its metabolites) by HG-AAS (hydride generation-atomic absorption spectrometry). In the analysis of SRMs (standard reference materials), method E (addition of 0.4% L-cysteine to pre-reductant and use 0.04M HCl as carrier acid) showed the most accurate results compared with the reference values. In the analysis of 30 urinary samples, analytical results were significantly different depend on the component of pre-reductant and the concentration of carrier acid. When the concentration of carrier acid was higher, the analytical result was lower. The recovery rates of MMA (monomethylarsonic acid) and DMA (dimethylarsenic acid) were varied by the concentration of pre-treatment acid and carrier acid and hydride generation reagents. When the concentration of carrier acid was 1.62 M (5% HCl), the recovery rates of DMA was 1%. The recovery rates of MMA and DMA in method E (=V) were 102% and 100%, respectively. The results of this study suggest that the component and concentration of pre-reductant and carrier acid must be carefully adjusted in the analysis of urinary arsenic, and method E is recommendable as the most precise analytical method for determination of urinary toxic arsenic.

Relationship between Heavy Metal Concentrations in the Soil with the Blood and Urine of Residents around Abandoned Metal Mines

Objectives: This study was conducted in order to examine the relationship between heavy metal concentrations in the soil and the level of heavy metals in the blood or urine of 216 local residents living near abandoned metal mines. Methods: Residents around abandoned metal mines were interviewed about their dietary habits, including seafood consumption, medical history, cigarette smoking, and drug history. Metal concentrations in the soil were determined by atomic absorption spectrophotometer (AA-7000, Shimadzu, Japan). Lead (Pb) and cadmium (Cd) contents in the blood or urine were analyzed by GF-AAS (AA-6800, Shimadzu). Mercury (Hg) contents in the blood were determined by means of a mercury analyzer (SP-3DS, NIC). Arsenic (As) content in the soil and urine were measured by a HG-AAS (hydride vapor generation-atomic absorption spectrophotometer). Results: The heavy metal concentrations in the soil showed a log normal distribution and the geometric means of the four villages were 8.61 mg/kg for Pb, 0.19 mg/kg for Cd, 1.81 mg/kg for As and 0.035 mg/kg for Hg. The heavy metal levels of the 216 local residents showed a regular distribution for Pb, Cd, Hg in the blood and As in the urine. The arithmetic means were3.37 µg/dl for Pb, 3.07 µg/l for Cd and 2.32 µg/l for Hg, 10.41 µg/l for As, respectively. Conclusions: As a result of multi-variate analysis for the affecting factors on the bodily heavy metal concentrations, gender and concentration in the soil (each, p<0.01) for blood lead levels; gender and smoking status (each, p<0.01) for blood cadmium levels; gender (p<0.01) for urine arsenic levels; gender, age and concentration in the soil (p<0.01) for blood mercury levels were shown to be the affecting factors.

Investigation and Risk Assessment of Heavy Metals Contamination around an Abandoned Metal Mine in Korea

Recently, heavy metals contamination of the agricultural soil and crops surrounding mining areas has been identified as one of the most serious environmental problems in South Korea. The Ministry of the Environment in Korea conducted a Preliminary National Environmental Health Survey (PNEHS) in abandoned metal mines in 2007. The priority for a subsequent detailed examination was ranked from the results of PNEHS. The studied mine which was ranked as being of the highest priority is located in the midwestern part of Korea and was operated from 1911 to 1985. In this study, the contamination levels of the heavy metals in the abandoned metal mine were investigated. From the results, the average daily dose (ADD), target hazard quotient (THQ) and target cancer risk of the heavy metals were evaluated. The concentration of arsenic (As) in all of the tailings from the mine was higher than its countermeasure standard of Korea. In particular, the highest concentration of As, 330 ㎎/㎏, was up to 15 times higher than its countermeasure standard. The average concentration of As in agricultural soils was higher than the warning standard of Korea, and higher than its countermeasure standard at six sites. The average concentrations of the analyzed heavy metals in agricultural soil were below the warning standard, but concentrations of cadmium (Cd) and lead (Pb) at 4 sites were higher than its warning standard. The average concentration of As in surface water exceeded the warning standard of Korea. The value of the THQ of As for the tailings was higher than the health protection standard 1. The value of THQ of As for the farmlands was lower than the standard, while the hazard index (HI) of As was higher than the standard. The value of target cancer risk (TCR) of As, 6.44 × 10?⁴, were higher than the health protection standard of a lifetime risk for TCR at 1 × 10??. This suggests that the residents around the metal mines are exposed to As pollution with a carcinogenic risk.

Health Effect and Blood Lead Concentration among Residents in Gwangyang and Yeosu

Objectives: The objective of this study was to evaluate the distribution of blood lead concentrations of residents in the areas surrounding an industrial complex. Methods: During the three-month period from August to October 2012, informed consent was obtained from a total of 417 residents in Gwangyang and Yeosu. We collected blood samples from all subjects, and their demographic characteristics were acquired using a questionnaire. The blood samples were analyzed using an atomic absorption spectrometer and data analysis was conducted using IBM SPSS version 21.0. Results: The geometric mean concentration of blood lead in all subjects was 1.85 μg/dL. The highest (p<0.01) blood lead concentrations were in the current drinking group (2.24 μg/dL). Blood lead concentrations in the smoking group (0.59 μg/dL) were significantly (p<0.05) higher than those in the non-smoking group (0.24 μg/dL). Risk assessment was performe using the Korean National Environmental Health Survey (KNEHS) as a reference. The hazard indices of blood lead in males and females were 0.65 and 0.52, respectively Conclusion: We provided baseline data for reference values of toxicity and heavy lead concentrations. Our results might be useful for further evaluation of risks due to exposure to heavy metals via oral, air, and percutaneous routes.

Concentration of volatile organic compounds(VOCs) in ambient air and level of residents in industrial area

Objectives: The purpose of this study is to investigate the atmospheric concentration of VOCs and the urinary concentration of t,t-MA, HA, MA in the industrial complex of Yeosu, South Jeolla Province. Methods: In order to study seasonal patterns of air concentration of VOCs, measurements were taken at five sampling sites around Yeosu from June 2013 to June 2014. Urinary metabolite excretionsfrom 671 subjects, exposure and comparison area were analyzed. Results: The average concentration of VOCs in the air was 1.53ppb for benzene, 0.73ppb for toluene, 0.22ppb for ethylbenzene, 0.52ppb for xylene and 0.12ppb for styrene. The concentration of benzene was somewhat higher than the year-average standard (5 ㎍/㎥, about 1.5ppb) of the domestic air-environment criteria newly established in 2010.The metabolic concentration of VOCs in the urine of the entire sample was analyzed at 47.76µg/g cr., 213.07mg/g cr., and 290.09µg/g cr. for t,t-MA, HA, and MA, respectively. Compared with the average values for Korea as presented in the first basic survey of national environmental conservation (49.8µg/g cr. for t,t-MA, 0.17g/g cr. for HA, and 0.26mg/g cr. for MA), the metabolic concentrations of HA and MA in urine were higher than the average values. Conclusions: The concentration of VOCs in the air and urinary metabolites of the exposed and control areas showed that the concentrations of all substances were higher in the exposed area than in the control area.

Urinary Cadmium Concentration of Residents around Industrial Complex in Gwangyang and Yeosu

Objectives: The objective of this study was to evaluate the distribution of urine cadmium levels of residents in the surrounding areas of an industrial complex. Methods: During the period of three month from August to October 2012, informed consent was obtained from a total of 362 residents in Kwangyang and Yeosu. We collected urine sample from all subjects and their demographic characteristics, including alcohol drinks and smoking habits, using a questionnaire. The urine samples were analyzed using atomic absorption spectrometer. Results: The urinary cadmium geometric mean concentration of total participants was 0.87 μg/g cr. The results of this study showed that higher urine cadmium levels were observed in females and some subjects with a higher level of education level and a lower BMI. Also, those subjects who preferred to take vegetables and took fish 3 days before urine sampling procedure revealed higher urine cadmium concentrations. The urine cadmium concentrations of subjects in the exposed area(0.91 μg/g cr) were significantly higher than those in the control area(0.78 μg/g cr). Conclusions: An additional study is needed to assess health risks of residents in the vicinity of environment-unfriendly areas, coupled with endeavors to examine possible heavy metals contamination factors that may affect the human body.

Cerebral Activity by Motor Task in Welders Exposed to Manganese through fMRI

Objectives: The purpose of this study is to analyze the effects of chronic exposure by welders to manganese (Mn) through an analysis of the degree of brain activity in different activities such as cognition and motor activities using the neuroimaging technique of functional magnetic resonance imaging (fMRI). The neurotoxic effect that Mn has on the brain was examined as well as changes in the neuro-network in motor areas, and the usefulness of fMRI was evaluated as a tool to determine changes in brain function from occupational exposure to Mn. Methods: A survey was carried out from July 2010 to October 2010 targeting by means of a questionnaire 160 workers from the shipbuilding and other manufacturing industries. Among them, 14 welders with more than ten years of job-related exposure to Mn were recruited on a voluntary basis as an exposure group, and 13 workers from other manufacturing industries with corresponding gender and age were recruited as a control group. A questionnaire survey, a blood test, and an fMRI test were carried out with the study group as target. Results: Of 27 fMRI targets, blood Mn concentration of the exposure group was significantly higher than that of the control group (p