Association of cadmium with diabetes in middle-aged residents of abandoned metal mines: the first health effect surveillance for residents in abandoned metal mines

OBJECTIVE: The aim of this study was to determine the association between urinary cadmium (U-cd) concentration and diabetes in middle-aged Korean residents of abandoned mines using the first Health Effect Surveillance for Residents in Abandoned Metal mines (HESRAM). METHODS: This study was cross-sectional study conducted on 719 residents between 40-70 years in 38 abandoned metal mines in Korea. Data was collected by HESRAM from 2008 to 2011. The correlation coefficient of U-cd and fasting blood glucose, odds ratio in urinary cadmium tertiles and diabetes prevalence was analyzed according to the sex category. RESULTS: The correlation coefficient U-cd concentration and fasting blood glucose was 0.182 in male. Logistic regression analysis in male revealed a third tertile odds ratio of U-cd (2 mug/g creatinine < U-cd) while diabetes prevalence was 1.81 (95 % CI 1.05-3.12) with adjusted age, BMI, smoking and alcohol consumption, region, family income. On the other hand, the odds ratio for third tertile of U-cd (3 mug/g creatinine < U-cd) between diabetes prevalence in female was 1.39 (95 % CI 0.52-3.72) in addition to adjusted menopausal status. CONCLUSIONS: Environmental exposure to cadmium in abandoned mine residents was associated with diabetes in male. Closed monitoring and periodic evaluation of the health effects of chronic environmental exposure on abandoned mines residents will be needed.

Blood Cadmium Concentration of Residents Living near Abandoned Metal Mines in Korea

The purpose of this study was to investigate demographic and lifestyle variables and blood cadmium concentrations in residents living near abandoned metal mines in Korea. Blood cadmium concentrations were measured in 15,161 subjects living around abandoned metal mines (exposed group, n = 14,464) and compared with those living in designated control areas (control group, n = 697). A questionnaire was provided to all subjects to determine age, gender, mine working history, times of residence, smoking habits and dietary water type. The geometric mean (95% confidence intervals) of blood cadmium concentration (1.25 [1.24-1.27] microg/L) in the exposed group was significantly higher than in the control group (1.17 [1.13-1.22] microg/L). Mean residence time and mine working history in the exposed group were significantly higher than in the control group. Blood cadmium concentrations increased with increasing age, and residence time in both groups, and blood cadmium concentrations were higher in current-smokers than in non-smokers in both groups. This study shows the geometric mean of blood cadmium concentration in abandoned mining areas are higher than in non-mining areas in the general adult Korean population.

Four Cases of Abnormal Neuropsychological Findings in Children with High Blood Methylmercury Concentrations

BACKGROUND: Methylmercury (MeHg) easily crosses the blood-brain barrier and accumulates in the brain. Accumulated MeHg will cause neurological symptoms. We report four pediatric cases of neuropsychological findings with high blood MeHg concentrations. CASE PRESENTATION: Four children were admitted for follow-up study because their total mercury (THg) concentration in the blood was found to be high during a national survey. Case 1 was a 9-year-old female with a 16.6 microg/l blood THg concentration in the survey. During admission, the blood THg, hair THg, and blood MeHg concentration(mercury indices) were 21.4 microg/l, 7.2 microg/g, and 20.1 microg/l, respectively. In our neuropsychological examination, cognitive impairment and attention deficit were observed. Her diet included fish intake 2-3 times per week, and she had been diagnosed with epilepsy at 3 years of age. Case 2 was a 12-year-old male with blood THg of 15.4 microg/l in the survey and the mercury indices were 12.7 microg/l, 5.7 microg/g, and 11.8 microg/l, respectively, on admission. He was also observed to have attention-deficit/hyperactivity disorder. Case 3 was a 10-year-old male child with blood THg of 17.4 microg/l in the survey, and the mercury indices on admission were 21.6 microg/l, 7.5 microg/g and 21.5 microg/l, respectively. In his case, mild attention deficit was observed. Case 4 was a 9-year-old male with blood THg of 20.6 microg/l in the survey and the mercury indices were 18.9 microg/l, 8.3 microg/g, and 14.4 microg/l, respectively, on admission. Mild attention difficulty was observed. CONCLUSION: We suggest that fish consumption may be the main source of MeHg exposure, and that MeHg may have been the cause of the neuropsychological deficits in these cases.

Association between Low-level Mercury Exposure and Neurobehavioral Functions in Korean Adults Living in a Coastal City

OBJECTIVES: The aim of this study was to determine the association between low-level mercury exposure and neurobehavioral functions in adults living in coastal regions of Korea. METHODS: We selected 172 adults aged 20-65 years living in a city in the coastal region of Korea. A sociodemographic survey was conducted, mercury levels in the blood, urine, and hair were measured, and the associations according to computerized neurobehavioral tests were determined using univariate analysis. After adjustment for associated variables, a multivariate linear regression analysis was performed. RESULTS: The geometric mean mercury levels in the blood, urine, and hair were 5.41 microg/L (range, 0.00-15.84 microg/L), 1.17 microg/g-creatinine (range, 0.00-32.86 microg/g-creatinine), and 1.37 mg/kg (range, 0.42-6.56 mg/kg), respectively. Variables that were associated with simple reaction time according to the neurobehavioral test results were age and urine mercury level. Variables associated with choice reaction time were the recent use of Korean traditional medicine and urine mercury level. Variables associated with the right-hand finger tapping speed test were age, gender, smoking behavior, education level, monthly household income, and urine mercury level. Variables associated with the left-hand finger tapping speed test were age, gender, education level, and urine mercury level. After adjustment for associated variables, there was no significant association between urine mercury level and simple reaction time (beta=25.96; p=0.47), choice reaction time (beta=50.37; p=0.32), or the number of left-hand finger taps (beta=-1.54; p=0.21). However, urine mercury level was significantly associated with the number of right-hand finger taps (beta=-3.86; p=0.01). CONCLUSIONS: We found no evidence that low-level mercury exposure in adults is associated with deficits in neurobehavioral functions. A longer follow-up study is required to confirm this conclusion.

The Relationship between Fish Consumption and Blood Mercury Levels in Residents of Busan Metropolitan City and Gyeongnam Province / 農村醫學 地域保健

OBJECTIVES: The objective of this study was to identify the relationship between fish consumption and blood mercury levels in a sample of adult Koreans. METHODS: The study subjects were 299 residents of Busan (male: 65, female: 234) and 185 residents of Namhae (male: 69, female: 116), South Korea. Demographic characteristics, current smoking, current drinking, fish consumption per week, past history of amalgam treatment, and residential district were recorded by trained interviewers in June and July, 2009. We considered a portion of fish to be equivalent to 70 gm weight, and calculated amounts of fish consumed per week. Using chi-square tests, t-tests, ANOVA, and multiple linear regression analysis, we estimated the relationships between blood mercury levels and amount of fish consumed per week and other factors. RESULTS: The mean blood mercury level of our subjects was 6.61 microgram/L, higher than the criterion defined by the United States Environmental Protection Agency (EPA) (5.8 microgram/L). In multiple linear regression analysis, residential district and amount of fish consumed per week were associated with blood mercury levels. However, marital status, current drinking, and gender, and age were not associated with blood mercury levels. CONCLUSIONS: In conclusion, we suggest the implementation of systematic and periodic population-based studies to decrease the risks of mercury poisoning among South Koreans who consume fish as a regular part of the diet.

Global Trends in Mercury Management / 예방의학회지

The United Nations Environmental Program Governing Council has regulated mercury as a global pollutant since 2001 and has been preparing the mercury convention, which will have a strongly binding force through Global Mercury Assessment, Global Mercury Partnership Activities, and establishment of the Open-Ended Working Group on Mercury. The European Union maintains an inclusive strategy on risks and contamination of mercury, and has executed the Mercury Export Ban Act since December in 2010. The US Environmental Protection Agency established the Mercury Action Plan (1998) and the Mercury Roadmap (2006) and has proposed systematic mercury management methods to reduce the health risks posed by mercury exposure. Japan, which experienced Minamata disease, aims vigorously at perfection in mercury management in several ways. In Korea, the Ministry of Environment established the Comprehensive Plan and Countermeasures for Mercury Management to prepare for the mercury convention and to reduce risks of mercury to protect public health.

Analysis of Methylmercury Concentration in the Blood of Koreans by Using Cold Vapor Atomic Fluorescence Spectrophotometry

BACKGROUND: Methylmercury is an organic form of mercury that is highly toxic to humans. Here, we present and establish a novel method to detect methylmercury concentrations in the blood of Koreans. METHODS: Methylmercury concentration was analyzed with an automated methylmercury analytic system (MERX, Brooks Rand Co., USA) using cold vapor atomic fluorescence spectrophotometry (CVAFS). A variety of biological materials were digested in methanolic potassium hydroxide solution. The analysis method was validated by examination of certified reference material (955c, National Institute of Standard and Technology, USA). We randomly selected 30 Korean adults (age 20 yr or older) to analyze total blood mercury and methylmercury concentrations. RESULTS: The detection limit and methylmercury recovery rate using this method were 0.1 pg/L and, 99.19% (range: 89.33-104.89%), respectively. The mean blood concentration of methylmercury was 4.54+/-2.15 microg/L (N=30). The mean proportion of methylmercury to the total mercury concentration was 78.27% (range: 41.37-98.80%). CONCLUSIONS: This study is the first report to analyze blood methylmercury concentration using CVAFS in Korea. We expect that this method will contribute to the evaluation of mercury exposure and the assessment of the toxicological impact of mercury in future studies.

The Effects of the Frequency of Fish Consumption on the Blood Mercury Levels in Koreans / 대한산업의학회지

OBJECTIVE: We studied two districts in Korea in order to investigate if the frequency of fish consumption has an effect on the blood mercury levels. METHODS: This survey was conducted on 164 fishing district residents in Geoje city and 219 agricultural district residents in Changwon city from July to August in 2008. The data on the demographic characteristics, the living environment, lifestyle habits and the frequency of fish consumption was collected by interviewers. We used ANOVA to estimate the particular relevance between the frequency of fish consumption and the blood mercury concentration, and other various factors. RESULTS: The mean total blood mercury level was 6.54+/-4.01 microgram/L for the total study population. Our results were even higher than that of the National Health and Nutrition Examination Survey (USA) in, 2001~2002 and the German Environmental Survey in, 1998. In this study, there was a significant difference for the frequency of eating fish between the groups. (p<0.01, The level of the groups that ate fish 3 to 4 times per week was significantly higher as compared with the level of the other groups that ate fish 2 to 3 times per month and 1 to 2 times per week, respectively). As the frequency of fish consumption increased, so did the blood mercury concentration. CONCLUSIONS: We found that the blood mercury concentration increases along with fish consumption and this was statistically significant and this fact reveals that fish consumption is positively related to the blood levels of mercury. Accordingly, we need systematic and periodic research on the general population to prevent mercury poisoning, which can be caused by low-level mercury exposure from dietary intake such as chronic fish consumption.

Blood and Urinary Cadmium Concentration of Residents around Abandoned Metal Mines in Busan and Gyeongsangnam-do / 대한산업의학회지

OBJECTIVES: To evaluate the blood and urinary cadmium concentration levels of around abandoned metal mines in comparison with a control group. METHODS: Blood and urinary cadmium concentration levels were analyzed through investigations of the dietary habits and dietary water of subjects living near abandoned metal mines (exposure group) (n=190) in comparison with those living in designated control areas (control group) (n=256). RESULTS: The blood cadmium (1.93 microgram/l) and urinary cadmium (2.41 microgram/g cr) concentrations of the exposure group were significantly higher than those of the control group (blood cadmium: 1.19 microgram/l, urinary cadmium: 1.94 microgram/g cr). Both concentrations were significantly higher in vegetarians in both groups. CONCLUSIONS: The exposure group had higher blood and urinary cadmium concentrations than the control group. We attributed the elevated blood and urine cadmium levels in the abandoned mine residents to the influence of the abandoned mine sites.

Health Effect Assessment on Volunteers Involved in the Cleanup Operation Following the Hebei Spirit Oil Spill Along the Taean Coast, Korea / 대한산업의학회지

OBJECTIVE: The objetive of this study is to assess the level of oxidative stress by the exposure to volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) in volunteers who cleaned up the crude oil spilled from the Hebei Spirit on the Coast of Taean County, Korea. METHODS: The study subjects were 46 volunteers and 37 controls from the National Institute of Environmental Research. A self-administered questionnaire was used for volunteers to examine their working environment and health effects. Urinary concentrations of hippuric acid, 1-hydroxypyrene, and 2-naphthol were measured as exposure markers for VOCs and PAHs, and urinary thiobarbituric acid reactive substances (TBARS) and 8-hydroxydeoxyguanosine (8-OHdG) levels were measured as oxidative stress markers. RESULTS: Sixty-four percent of the respondents presented a variety of symptoms, including sore eyes and throat, nausea, dizziness, headache, low back pain, and leg pain after participating in the cleanup operation. Urinary 2-naphthol and TBARS concentrations appeared higher in the volunteers. Univariate and multivariate analyses showed that urinary TBARS and 8-OHdG levels were positively correlated with urinary 2-naphthol and 1-hydroxypyrene concentrations respectively, especially among the volunteers. CONCLUSIONS: The result implies that participating in cleanup work of oil spills may have a possibility to induce oxidative damage by exposure to PAHs in crude oil.

Effects of the Exposure to Polycyclic Aromatic Hydrocarbons or Toluene on Thiobarbituric Acid Reactive Substance Level in Elementary School Children and the Elderly in a Rural Area / 예방의학회지

OBJECTIVES: Polycyclic aromatic hydrocarbons (PAH) and toluene have been reported to induce reactive oxygen species and oxidative stress. This study was performed to investigate the effects of low level exposure to PAHs or toluene on the lipid peroxidation level in elementary school children and the elderly in a rural area. METHODS: Forty seven elementary school children and 40 elderly people who were living in a rural area and not occupationally exposed to PAH or toluene were the subjects of this study. Information about active or passive smoking and diet was obtained using a self-administered questionnaire. The urinary 1-hydroxypyrene (1-OHP), 2-naphthol, hippuric acid and thiobarbituric acid reactive substance (TBARS) concentrations were measured, and these values were corrected with the urinary creatinine concentration. RESULTS: In school children, the geometric means of the urinary 1-OHP, 2-naphthol, hippuric acid and TBARS levels were 0.02 ymol/mol creatinine, 0.47 micron mol/mol creatinine, 0.14 g/g creatinine and 0.95 micron mol/g creatinine, respectively. Those values for the elderly were 0.07 micron mol/mol creatinine, 1.87 micron mol/mol creatinine, 0.11 g/g creatinine and 1.18 micron mol/g creatinine, respectively. The mean levels of urinary 1-OHP, 2-naphthol and TBARS were significantly higher in the elderly subjects than in the children. The urinary TBARS level was not correlated with the urinary 1-OHP, 2-naphthol and hippuric acid, but they were correlated with the age of the subjects. CONCLSIONS: These results suggest that low level inhalation exposure to PAH or toluene does not markedly increase lipid peroxidation, and age is a significant determinant of lipid peroxidation.

Investigation on Health Effects of an Abandoned Metal Mine

To investigate potential health risks associated with exposure to metals from an abandoned metal mine, the authors studied people living near an abandoned mine (n=102) and control groups (n=149). Levels of cadmium, copper, arsenic, lead, and zinc were measured in the air, soil, drinking water, and agricultural products. To assess individual exposure, biomarkers of each metal in blood and urine were measured. beta2-microglobulin, alpha1-microglobulin, and N-acetyl-beta-glucosaminidase and bone mineral density were measured. Surface soil in the study area showed 2-10 times higher levels of metals compared to that of the control area. Metal concentrations in the groundwater and air did not show any notable differences between groups. Mean concentrations of cadmium and copper in rice and barley from the study area were significantly higher than those of the control area (p<0.05). Geometric means of blood and urine cadmium in the study area were 2.9 microgram/L and 1.5 microgram/g Cr, respectively, significantly higher than those in the control area (p<0.05). There were no differences in the levels of urinary markers of early kidney dysfunction and bone mineral density. The authors conclude that the residents near the abandoned mine were exposed to higher levels of metals through various routes.

Mercury Concentrations of Maternal and Umbilical Cord Blood in Korean Pregnant Women: Preliminary Study / 대한산업의학회지

OBJECTIVES: To evaluate the level of maternal and prenatal mercury exposure and to analyze the related factors. METHODS: Fifty-nine pregnant women were recruited into this study after obtaining informed consent. Samples were collected at delivery from normal pregnant women who were living in the city of Busan, Korea. Mercury concentrations in maternal and umbilical cord blood samples were measured using a gold-amalgam collection method. The total and methyl mercury levels of 36 of the 59 pregnant women were analyzed after randomization, and the results were compared. RESULTS: The mean total mercury concentration was 3.16+/-1.21 ppb and 5.43+/-2.22 ppb in maternal and cord blood, respectively. The average, maternal blood mercury level was lower than the prescribed toxic limit for human (WHO, 5 ppb), whereas the cord blood mercury was higher. The mercury exposure level exceeded the WHO recommendation in 5 (8.47%) cases of maternal blood and 29 of (49.15%) cord blood. There was a significant correlation between maternal and cord blood mercury concentrations. Total mercury and methyl mercury concentrations of the 36 random pregnant women were 3.06+/-1.17 ppb, and 2.60+/-1.11 ppb in maternal blood, and 5.20+/-2.36 ppb, and 4.70+/-1.97 ppb in cord blood, respectively. Methyl mercury accounted for 85.0% of the total mercury in maternal blood and 90.4% in cord blood. There was a significant correlation between total and methyl mercury concentrations. CONCLUSIONS: The study results suggest that mercury concentrations of cord blood may be regarded as indicative of high prenatal mercury exposure. Therefore, further studies are necessary to explain the cause of high mercury concentrations in cord blood, and to examine its relationship with various health indices.