Blood lead concentration and exposure related factors in Korea from the National Environmental Health Survey (KoNEHS) II (2012-2014).

This study evaluated lead concentrations in blood and related factors among the South Korean population based on data from the Korea National Environmental Health Survey (KoNEHS) II (2012-2014) conducted by the National Institute of Environmental Research and the Ministry of Environment. Personal data were obtained from non-institutionalized civilian Korean individuals in an interview with trained community surveyors using a structured questionnaire (n = 6,455, aged 19 or older, mean age 49.7 years). The lead concentrations in whole blood were analyzed by atomic absorption spectrophotometry (AAS) with a Zeeman-effect-based background corrector. The precision and accuracy of the analytical methods were verified by internal and external quality controls (G-EQUAS, Germany). Statistical analysis was performed using weighted KoNEHS II data separated by sex, and the lead concentration was expressed as a geometric mean (GM). Multiple linear regression was performed using the SPSS 23.0 software package (SPSS Inc., Chicago, IL, USA). The total GM of lead concentrations was 19.5 µg/L. Lead concentrations increased with age and were higher in males (22.8 µg/L) than in females (16.6 µg/L). Smokers and drinkers had higher concentrations than non-smokers and non-drinkers of both sexes. People who used herbal medications had higher concentrations than those who did not among females. People of both sexes living in rural areas had higher lead concentrations than those in urban areas. Lead concentrations also varied with educational level, total family income, the type of water regularly consumed, and occupation. The average lead concentration of the general adult population in Korea has rapidly decreased over time from 45.8 µg/L (1999) to 19.45 µg/L (2012-2014); however, it remains higher than that of the United States, Germany, and Canada. The factors significantly related to lead concentration in South Korea were age, sex, smoking and alcohol drinking status, herbal medication usage by females, residential area, drinking water at home, and occupation. These factors could be used to improve occupational and environmental hygiene among the Korean population.

Serum concentrations of per- and poly-fluoroalkyl substances and factors associated with exposure in the general adult population in South Korea.

Per- and polyfluoroalkyl substances (PFASs) are ubiquitous contaminants found worldwide, including in South Korea. As a result, they are frequently detected in Koreans. However, there is limited representative data and information on potential sources in Korea. Therefore, we measured the serum concentrations of ten PFASs in nationally representative samples of the Korean population (n=1874, 18-69 years) and evaluated the factors associated with their exposure. Serum PFOS, PFDA, PFOA, and PFNA were detected in nearly all participants (83.1-99.9%). However, serum PFPA, PFHxA, and PFHpA were almost undetected (<0.5% of participants). PFOS had the highest population-weighted geometric mean of 10.23ng/mL (95% CI: 9.99-10.47), which was followed by PFOA with 2.85ng/mL (95% CI: 2.73-2.97) and PFDA with 2.17ng/mL (95% CI: 2.12-2.23). PFNA, PFDA, PFHxS, PFOA, and PFOS concentrations were higher in males (p<0.001) and older adults (p<0.001). PFNA was higher in those who used wax, polish, and water-resistant materials (adjusted proportional change=1.14; 95% CI: 1.08-1.22), and those who ate cooked fish (1.16; 95% CI: 1.03-1.31) compared to those who ate nearly no fish. PFDA was higher in those who used herbicides and pesticides (1.05; 95% CI: 1.02-1.09), those who drank beverages in a plastic bag on a daily basis (1.10; 95% CI: 1.03-1.19), and those who ate raw fish (1.15; 95% CI: 1.03-1.29) or cooked fish (1.13; 95% CI: 1.05-1.23) compared to those who ate nearly no fish. PFHxS was higher in those who used traditional Korean health supplement foods (1.08; 95% CI: 1.01-1.15). PFOA was higher in those who used plastic wrap in a microwave daily or weekly (1.08; 95% CI: 1.00-1.16), and those who used disposable paper cups (1.07; 95% CI: 1.01-1.13). PFOS was lower in underweight participants (0.84; 95%CI: 0.75-0.93) compared to those who were obese, and higher in those who exercised regularly (1.08; 95% CI: 1.03-1.14) or irregularly (1.06, 95% CI: 1.01-1.12) compared to those who did not exercise. Subjects who used severely damaged Teflon appliances had lower concentrations of PFOA (0.78, 95% CI: 0.65-0.95), while regular use of Gore-Tex goods was related to higher PFNA (1.15, 95% CI: 1.03-1.28) and PFDA (1.11; 95% CI: 1.02-1.20) levels. These findings suggest that most Koreans are frequently exposed to PFASs, and that serum concentrations of PFASs vary with age, sex, and exposure factors.

Decrease in the urine cotinine concentrations of Korean non-smokers between 2009 and 2011 following implementation of stricter smoking regulations.

This study aimed to determine if there was an association between the implementation of smoking regulation policies and the urine cotinine concentrations of Korean non-smokers. The subjects of this study were 4612 non-smoking Korean citizens (aged 19 or older) selected from the first stage of the Korean National Environmental Health Survey conducted by the National Institute of Environmental Research from 2009 to 2011. Cotinine concentrations in urine were measured by GC-MS (limit of detection: 0.05 ng/mL). Changes in the urine cotinine concentration were analyzed using a weighted general linear model and linear regression and values were shown as geometric mean (GM). The GM urine cotinine concentration decreased over time (2.92 ng/mL in 2009, 1.93 ng/mL in 2010, and 1.25 ng/mL in 2011). The total decrease in the subjects' urine cotinine concentration between 2009 and 2011 was 2.79 ng/mL, representing a relative decrease of 54.7%. The decrease in GM urine cotinine concentration in each subgroup ranged from 2.17 ng/mL to 3.29 ng/mL (relative decreases of 46.4% and 62.8%, respectively), with the largest absolute reductions in subjects in the following groups: females, aged 40-49 years, detached residence type, no alcohol consumption, employed, secondhand smoke exposure. All groups had negative regression coefficients, all of which were significant (p < 0.001). Our results provide indirect indicators of the effectiveness of smoking regulation policies including the revision of the National Health Promotion Act in Korea.

Effects of perfluorooctane sulfuric acid on placental PRL-family hormone production and fetal growth retardation in mice.

Perfluorooctane sulfuric acid (PFOS) is a persistent organic pollutant, causes fetal growth retardation but the mechanism is still unclear. This study focused on PFOS-induced toxicity such as placental trophoblast cell histopathological changes, endocrine function (i.e., prolactin (PRL)-family hormone production) and subsequent fetal growth retardation in mice. Maternal body weight gain, placental and fetal weights were significantly decreased in proportion to PFOS dosage. Placental efficiency (fetal weight/placental weight) was significantly reduced dose-dependently. Necrotic changes were observed in PFOS-treated placental tissues, and the area of injury increased dose-dependently. Finally, mRNA levels and maternal serum concentrations of the PRL-family hormones (mPL-II, mPLP-Cα, mPLP-K) were significantly reduced dose-dependently. In addition, the changing pattern between PRL-family hormone concentrations and fetal body weight was positively correlated. These results suggest that gestational PFOS treatment induces placental histopathological changes and disruption of endocrine function, finally may lead to fetal growth retardation in mice.

Blood lead concentration and related factors in Korea from the 2008 National Survey for Environmental Pollutants in the Human Body.

This study evaluated blood lead concentrations in the Korean general population and the correlation between various exposure sources using data from the 2008 Korea National Survey for Environmental Pollutants in the Human Body (National Institute of Environmental Research, Korea). The general and occupational characteristics were gathered from 5136 participants who were 20 years of age and older using a structured questionnaire. Blood lead concentrations were analyzed using an atomic absorption spectrophotometer. Statistical analysis was performed using multiple linear regressions of the log lead concentrations to the independent variables such as age, gender, smoke, herbal medication and drug consumption, drinking water, and living area. Geometric mean (GM) blood lead concentrations in Korean adults were 19.7 µg/l. The blood lead concentrations increased with age; the highest concentrations were found in the 50-69-year age group (p<0.001). Males were higher than in females (p<0.001). Current smokers and drinkers had higher concentrations than nonsmokers (p<0.001) and nondrinkers (p<0.001), respectively. People who took herbal medication and drug consumption were higher than those who did not (p<0.001). Education level was negatively associated with blood lead concentration (p<0.001). People living in or around industrial areas had elevated blood lead concentration (p<0.001). Family income was also negatively associated with lead concentration, but not significantly. For drinking water, the underground water (spring or well water) drinking group had higher concentrations than other types of water drinking groups, but not significantly (p=0.063). The blood lead concentrations by occupation were significant (p<0.034): the highest was in laborer and Agricultural-Fishery-Forestry and the lowest in office workers. In women, blood lead concentrations tended to decrease with increasing delivery times, but not significantly. The blood lead concentration (GM) of the general adult population in Korea has decreased over time from 45.8 µg/l (1999) to 19.7 µg/l (2008). Although it is still higher than in other countries such as the United States and Canada, it is rapidly decreasing. Gender, age, smoking and alcohol drinking status, herbal medication and drug consumption, education level, living area and occupation were significantly related to the blood lead concentrations in Korea.

Secondhand smoke exposure and urine cotinine concentrations by occupation among Korean workers: results from the 2008 Korea National Survey for Environmental Pollutants in the Human Body.

This study aimed to estimate the status of secondhand smoke (SHS) exposure through urine cotinine analysis among nonsmoking workers in Korea and to analyze factors affecting urine cotinine concentrations. Data were based on "The 2008 Korea National Survey for Environmental Pollutants in the Human Body," a cross-sectional study of the National Institute of Environmental Research of Korea. We selected 1448 nonsmoking adult workers from 200 localities to participate in this survey. Urine cotinine concentrations were analyzed using a gas chromatograph-mass selective detector. We calculated separate covariate-adjusted geometric means for socio-demographic variables for males, females, and total subjects by analysis of covariance (ANCOVA). Statistical analyses were performed using SPSS version 18.0 (SPSS Inc., Chicago, Ill.). The prevalence of self-reported exposure to SHS was 36.9%. The geometric mean (95% confidence interval) of urine cotinine concentrations among all participants was 16.50 (14.48-18.80) µg/L. Gender, living area, education, and SHS exposure showed significant differences in urine cotinine concentrations. The urine cotinine concentrations of farmworkers and blue-collar workers such as skilled agricultural, forestry, and fishery workers, and elementary occupations were higher than those of white-collar workers such as clerical support workers, technicians, and associate professionals. Such a high proportion of the population having high urine cotinine levels indicates widespread exposure to SHS among nonsmoking workers in Korea. Furthermore, the urine cotinine levels among nonsmoking workers exposed to SHS varied by occupation. The measured urine cotinine concentration is suggested to be a valuable indication of SHS exposure in Korea.

Perfluorooctanoic acid-induced inhibition of placental prolactin-family hormone and fetal growth retardation in mice.

Perfluorooctanoic acid (PFOA) is a persistent pollutant worldwide and even found in human cord blood and breast milk. Some animal studies have reported that PFOA causes developmental toxicity such as fetal weight loss, but the mechanism is still unclear. This study focused on developmental toxicity of PFOA, particularly impacts of PFOA on placental endocrine function such as placental prolactin (PRL)-family hormone gene expression and fetal growth in mouse. Time-mated CD-1 mice were dosed by gavage with 0, 2, 10 and 25 mg/kg B.W/day of PFOA (n-10) dissolved with de-ionized water from gestational day (GD) 11-16. During treatment, body weight of each pregnant mouse was measured daily. On day 16, caesarean sections were performed and developmental data were observed. Three placentas from three different pregnant mice were assigned to each of the following experiments. The mRNA levels of mouse placental lactogen (mPL)-II, prolactin like protein (mPLP)-E, -F and Pit-1α and ß isotype mRNAs, a transacting factor of mPLs and mPLPs genes, were analyzed using northern blot, in situ hybridization and RT-PCR, respectively. Maternal body weight gain was significantly declined from GD 13 in the PFOA treated groups compared to control. Developmental data such as fetal and placental weights were significantly decreased in accordance with PFOA dosage. Number of dead fetuses and post-implantation losses were significantly increased in the PFOA-exposed groups. In addition, placental efficiency (fetal weight/placental weight) was significantly reduced in PFOA treated groups in accordance with PFOA dosage. Histopathologic changes were observed in placenta. Dose dependent necrotic changes were observed in both 10 mg and 25 mg PFOA treated groups. Cell frequency of glycogen trophoblast cell and parietal trophoblast giant cell were decreased dose dependently in the junctional zone. In the labyrinth zone, sinusoidal trophoblast giant cell frequency was decreased in the 25 mg PFOA treated group. Also, morphological change such as crushed nuclear (atrophy) of trophoblast cells was observed in 25 mg PFOA treated group. Finally, mRNA levels of the mPL-II, mPLP-E, -F and Pit-1α and ß were significantly reduced in the PFOA treated groups dose dependently. In addition, the changing pattern between mPL-II, mPLP-E, -F mRNA levels and fetal body weight showed positive relationship. In conclusion, the inhibitory effects of PFOA on the placental prolactin-family hormone genes expression may be secondary effects to insufficient trophoblast cell type differentiation and/or increased trophoblast cell necrosis. The impacts of PFOA on placental development and endocrine function reduced the placental efficiency and partly contributed to the fetal growth retardation in the mouse.