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Settled house dust (SHD) is a reservoir for various contaminants, including endocrine-disrupting chemicals (EDCs), trace metals, and house dust mite allergens. This study aimed to characterize various chemical and biological contaminants in SHD and identify determinants governing the indoor contaminants. In total, 106 SHD samples were collected from 106 houses in Seoul and Gyeonggi Province, Korea, in 2021. Bedding dust samples were collected from 30 of these 106 houses. All participants completed a questionnaire comprised of housing and lifestyle-related factors. The samples were analyzed for 18 organophosphate flame retardants (OPFRs), 16 phthalates, five alternative plasticizers (APs), seven trace metals, and two house dust mite allergens (Dermatophagoides farinae type 1 [Der f1] and Dermatophagoides pteronyssinus type 1 [Der p1]). A multiple regression analysis was conducted to identify the determinants governing the concentrations and profiles of various contaminants. OPFRs, phthalates, APs, and trace metals were detected in all SHD samples, indicating ubiquitous contamination in indoor environments. Among the three EDC groups, APs were detected at the highest concentrations (geometric mean [GM] (geometric standard deviation, [GSD]): 1452 (1.6) μg/g in total), followed by phthalates (GM (GSD): 676 (1.4) μg/g in total) and OPFRs (GM (GSD): 10 (1.4) μg/g in total). Der f1 was detected in all bedding dust samples with significantly higher levels than Der p1 (GM (GSD): 0.1 (1.8) μg/g vs. 1.4 × 10

Parabens are common chemicals used as preservatives in foods, cosmetics, and personal care products. Although transdermal exposure to parabens occurs, studies on human pharmacokinetics (PK) following dermal exposure to parabens are scarce. In this study, the PK following dermal exposure to parabens was determined and compared with our previous findings on oral exposure. A paraben mixture cream containing 0.8% deuterated methyl-, ethyl-, and propylparaben (MeP-d

Several studies have been conducted among South Korean to investigate effects of high blood mercury (Hg) levels. In this study fetal body burden of Hg in 344 pregnant women were estimated using a physiologically-based pharmacokinetic model (PBPK) and its associative effects on the growth of infants were analyzed. The association between cord blood Hg and growth variables at birth was analyzed based on parameters such as the sex of the newborn, living area, maternal age group, gestation day, maternal body mass index . We investigated the effects of Hg on infant growth through follow-ups, using a non-linear mixed model. The mean Hg levels in maternal and cord blood were 4.47 μg/L and 7.35 μg/L, respectively. Among the subjects, the corresponding fetal body burden for Methylmercury ranged between 26.3-86.9 mg. Cord blood Hg levels positively correlated with length at birth. Furthermore, the high cord blood group showed greater growth rates compared to the low cord blood group. Therefore, we suggest that pregnant women should make efforts to mitigate exposures to Hg, specifically from diet. Further research is suggested to investigate the relationship between the follow-up growth of the infants and Hg levels, considering fish consumption, diet information, and other environmental pollutants.

The Korean National Environmental Health Survey (KoNEHS) program provides useful information on chemical exposure, serves as the basis for environmental health policies, and suggests appropriate measures to protect public health. Initiated on a three-year cycle in 2009, it reports the concentrations of major environmental chemicals among the representative Korean population. KoNEHS Cycle 3 introduced children and adolescents into the analysis, where the blood and urine samples of 6167 participants were measured for major metals, phthalates, phenolics, and other organic compounds. Lead, mercury, cadmium, metabolites of DEHP and DnBP, and 3-phenoxybenzoic acid levels of the Korean adult population tended to decrease compared to previous survey cycles but remained higher than those observed in the US or Canada. Both bisphenol A (BPA) and trans,trans-muconic acid concentrations have increased over time. Heavy metal concentrations (blood lead, and cadmium) in children and adolescents were approximately half that of adults, while some organic substances (e.g., phthalates and BPA) were high. BPA showed higher levels than in the US or Canada, whereas BPF and BPS showed lower detection rates in this cycle; however, as these are increasingly used as a substitute for BPA, further research is necessary. As environmental chemicals may affect childhood health and development, additional analyses should assess exposure sources and routes through continuous observations.

Physicochemical properties between colloidal engineered nanomaterials (ENMs) and aerosols released from consumer spray products were characterized. A dynamic light scattering (DLS), transmission electron microscopy (TEM), and inductively coupled plasma mass spectrometer (ICP-MS) were used to evaluate the suspended ENMs in the products. Direct-reading instruments, TEM, and ICP-MS were used to characterize the properties of aerosolized ENMs. The aerosolized organic compounds with ENMs were assumed to be vaporized for a short time after spraying. The median diameter of ENMs in product solutions measured by DLS was about 200-350 nm, while individual particle was confirmed from 3 to 50 nm by TEM. The size of aerosolized ENMs was ranged from 7 to 44 nm, and their aggregates were about 100-1000 nm in near distance. Some inorganic substances including raw nanomaterials were also found in the aerosol. The particles released from the propellant sprays were identified in far distance, while they were not found in far distance when pump sprays were used. The number concentration from the propellant sprays increased up to 6000 particles/cm3 /g at near distance and dispersed to far distance, while the most of droplets emitted from pump sprays were settled down near sprayer's location. We found other metals besides labeled ENMs are included in each product and the characteristics of the particles are different when they are sprayed.

Chemicals such as phthalates and phenolics have been associated with metabolic markers in humans. However, most studies have only looked at a limited number of chemicals, and little is known about their potential effects on adipokines in humans. In the present study, the associations between dozens of urinary chemicals, including phthalate metabolites and phenolics, and markers related to insulin resistance as well as major adipokines, were assessed among the women of reproductive age (n = 459, between 20 and 48 years of age) recruited from major cities in Korea between 2015 and 2016. Adipokines such as adiponectin and leptin, and insulin resistance related markers such as glucose and insulin, were analyzed in serum. Associations between urinary chemicals and the adipokines or insulin resistance related markers were assessed in two steps. First, ordinary least squares (OLS) regression was used to assess the association of each urinary chemical with the adipokines or insulin resistance related markers (single-pollutant model). Second, several chemicals were selected using elastic net regression and were subsequently analyzed with OLS regression model (multi-pollutant model), considering simultaneous exposure to multiple chemicals. In both single- and multi-pollutant models, several urinary chemicals consistently showed significant associations with adipokines or the insulin resistance related markers. The sum of di-(2-ethylhexyl) phthalate metabolites (ΣDEHPm) and ethyl paraben (EtP) were associated with increased serum adiponectin levels. Urinary ΣDEHPm levels also showed positive associations with fasting glucose. Moreover, urinary mono-methyl phthalate (MMP), mono-isobutyl phthalate (MiBP), and bisphenol S (BPS) levels showed positive associations with the homeostasis model assessment for insulin resistance (HOMA-IR). Interestingly, urinary propyl paraben (PrP) levels showed a negative association with HOMA-IR, in both models. Our observations show that among many consumer chemicals, phthalates may affect serum adipokines, and thus glucose, and insulin resistance in adult females. Further confirmation is warranted in other populations.

Arsenic (As) exposure has been extensively studied by investigating As species (e.g., inorganic arsenic (iAs), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA)) in urine, yet recent research suggests that blood could be a possible biomarker of As exposure. These investigations, however, were conducted on iAs-contaminated areas, and evidence on populations exposed to low levels of iAs is limited. This study aimed to describe the levels and distributions of As species in urine and blood, as well as to estimate methylation efficiency and related factors in the Korean population. Biological samples were obtained by the Korean Ministry of Food and Drug Safety. A total of 2025 urine samples and 598 blood samples were utilized in this study. Six As species were measured using ultra-high-performance liquid chromatography with inductively coupled plasma mass spectrometry (UPLC-ICP-MS): As(V), As(III), MMA, DMA, arsenobetaine (AsB), and arsenocholine (AsC). Multiple linear regression models were used to examine the relationship between As species (concentrations and proportions) and covariates. AsB was the most prevalent species in urine and blood. The relative composition of iAs, MMA, DMA, and AsC in urine and blood differed significantly. Consumption of blue-backed fish was linked to higher levels of AsB in urine and blood. Type of drinking water and multigrain rice consumption were associated with increased iAs concentration in urine. Except for iAs, every species had correlations in urine and blood in both univariate and multivariate analyses. Adolescents and smokers presented a lower methylation efficiency (higher %MMA and lower %DMA in urine) and females presented a higher methylation efficiency (lower %iAs, %MMA, and higher %DMA in urine). In conclusion, blood iAs concentration cannot represent urinary iAs; nonetheless, different compositions of urine and blood might reflect distinct information about iAs exposure. Further investigations on exposure factors and health are needed using low-exposure groups.

Personal care products (PCPs) are considered as a major source of paraben exposure; however, the dietary contribution is not well known. We compared the urinary levels of methyl-, ethyl-, and propyl-paraben (MeP, EtP, and PrP), and investigated their associations with fasting status and contacts with other potential exposure sources among Korea and the US adult women. A group of fasting, non-pregnant adult women (n = 469) was recruited from Seoul, Ansan/Incheon, and Jeju, Korea in 2015-2016, and their urine was measured for parabens. Non-fasting Korean women of matching age (25-45 years) were chosen from the Korean National Environmental Health Survey (KoNEHS) Cycle 3 (n = 579). For the US women, both fasting (n = 154) and non-fasting (n = 201) females were chosen from the NHANES 2015-2016 participants. In fasting Korean women, the urinary MeP, EtP, and PrP concentrations (median) were measured at 47.30, 17.90, and 2.30 ng/mL, respectively. Urinary EtP and PrP levels in fasting Korean women were significantly lower than those in non-fasting women (EtP and PrP median of 26.40 and 3.57 ng/mL). On average, the difference in urinary EtP levels by fasting status was greater among the highly exposed groups. In the US population, EtP levels were significantly lower (median ranged 1.55-1.80 ng/mL depending on fasting status), but MeP levels were higher (67.90-84.35 ng/mL) than those of the Korean population. When only fasting women were considered, the median EtP levels of Korean women were 11.5-fold greater than those of US women, suggesting that the non-dietary contributions of EtP exposure could not be ignored among Korean women. Regardless of fasting status, MeP and PrP were significantly correlated, and their urinary levels in fasting Korean women were correlated with the use of several personal care products. The major dietary and non-dietary sources that may explain EtP exposure in Korean women warrant further investigation.

Chronic kidney disease (CKD) is a global health threat of growing concern. Recently, exposure to endocrine disrupting compounds (EDCs) such as phthalates and bisphenol A has been suggested as a risk factor for CKD. However, most epidemiological studies have focused on a limited number of urinary chemicals. This study aimed to identify chemical determinants of the urinary albumin-to-creatinine ratio (ACR), which is a kidney function marker, among multiple major EDCs including phthalate metabolites, bisphenols, and benzophenones in a Korean female population (20–45 years old, n = 441). First, the creatinine-adjusted urinary concentration of each urinary chemical was associated with ACR in a linear regression model (single-pollutant model). Then, compounds with a significant association with ACR in the single-pollutant model were added in a multi-pollutant model and evaluated for their association with ACR. Moreover, to prevent potential reverse causality due to impaired kidney function, quartile analyses were performed for the subjects with healthy renal function (ACR

Urine was used as a part of a human biomonitoring study based on the excretion kinetics of less-persistent contaminants, such as phthalates and bisphenol A (BPA). Despite the advantages of being non-invasive and easy to collect, urine can show a large variability of concentrations of phthalate metabolites and BPA within a person depending on sampling time. Therefore, it is essential to assess the variability of urinary concentrations for comprehensive sampling design in the context of exposure and risk assessments. In this study, 18 phthalate metabolites and eight BPs were measured in all spot urine (n = 401) collected from 12 participants for seven consecutive days to evaluate within- and between-person variabilities. The intraclass correlation coefficients (ICCs) for all spot urines were poor for monomethyl phthalate (ICC: 0.002) and BPA (0.121) but were moderate for monoethyl phthalate (0.514) and monobenzyl phthalate (0.462). Based on the results of di (2-ethylhexyl) phthalate (DEHP) metabolites, the half-life and differences in metabolic capability seem to affect the ICCs. Urinary mono (2-ethylhexyl) phthalate (MEHP), a primary metabolite of DEHP, was suggested as a short-term exposure marker of DEHP in our study. Creatinine- and specific gravity-adjusted concentrations of phthalate metabolites and BPs resulted in increased ICCs, implying requirements for randomly collected spot urine. Most analytes in the first morning voids (FMVs) were correlated significantly with those in the daily composites, suggesting the feasibility of FMVs to estimate the daily exposure dose. This study facilitates a more comprehensive sampling design and data interpretation strategy for human biomonitoring studies.

This study aimed to quantify both chloromethylisothiazolinone (CMIT) and methylisothiazolinone (MIT) dissolved in different product brands and to characterize the exposure to these chemicals among humidifier disinfectant-associated lung injury (HDLI) patients. Both CMIT and MIT dissolved in different humidifier disinfectant (HD) products were quantified using gas chromatography&ndash, mass spectrometry. The inhalation level of CMIT and MIT was estimated based on HD-associated factors as reported by HDLI patients. A total of eleven HD products marketed until the end of 2011 were found to contain CMIT and/or MIT. The level of combined CMIT and/or MIT dissolved in these HD products ranged from 12 to 353 ppm. The level varied among HD products and the year of manufacture. The average inhalation levels were estimated to be 7.5, 4.1, and 3.2 &mu, g/m3 for the definite, probable, and possible groups, respectively. If probable and possible groups were collapsed together, the inhalation level of the collapsed group was significantly different from that of the definite group (p &lt, 0.001). All HDLI patients responded as having used HD not only while sleeping, but also as having a humidifier treated with HD within close proximity every day in insufficiently ventilated spaces. These HD use characteristics of patients may be directly/indirectly linked to the HDLI development.

Phthalates and bisphenol A (BPA), widely applied in industrial and consumer products, can affect hormones associated with the human reproductive system. Because the incidence of reproductive diseases is increasing, a comprehensive exposure assessment of phthalates and bisphenol analogues (BPs) is required for childbearing-aged women. Phthalate metabolites and BPs were measured in urine samples collected from 509 childbearing-aged women (20–48 years) in Korea to investigate their current exposure status, profiles, influencing factors, and potential health risks. DEHP metabolites and BPA were the dominant compounds found, indicating that they are highly consumed in daily life. Bisphenol S (BPS), as an alternative to BPA, was detected in most urine samples. Total concentrations of phthalate metabolites and BPs ranged from 3.42 to 3570 (GM: 45.6) ng/mL and from

Phthalates and environmental phenols might be associated with some benign diseases that have been found to be hormone-sensitive. Current knowledge on adverse effects of these chemicals among reproductive women is limited and often controversial. Therefore, the purpose of this study was to investigate the association between the urinary concentration of phthalates and environmental phenols and gynecological disorders from 512 women of reproductive age. The association between chemical concentration and disease in the control and case groups was statistically determined with the questionnaire survey data and measurements using the LC–MS/MS. The results have shown that DEHP metabolites, ethyl paraben and 3,4-DHB showed significant direct associations with leiomyoma and benign ovarian tumors (p < 0.05). We found statistically significant positive relationships between exposure to chemicals (some DEHP metabolites, DHB) and prevalence of gynecologic disorders (p < 0.05). Furthermore, the ORs for leiomyoma associated with these compounds in always user for personal care products (PCPs) was higher than those of sometimes user. High levels of urinary concentrations of these compounds such as DEHP metabolites and parabens and their metabolites showed significant associations with leiomyoma and benign ovarian tumors.

Bisphenol A (BPA) is one of the most widely used chemicals in various consumer products. In thermal papers such as receipts and tickets, BPA is used as a heat-activated developer. Cashiers are therefore suspected to be a vulnerable group of exposure to BPA, but neither contribution of receipt handling to the total body burden of BPA among cashiers, nor related health effects are well characterized. Female cashiers (n = 54) were recruited from seven retail shops of a major supermarket chain in Korea, and urinary levels of BPA and metabolic syndrome (MetS) related biomarkers were measured. In order to estimate the contribution of receipt handling to the body burden of BPA, an intervention was designed on the use of gloves: the subjects were asked not to wear gloves during the work for one week, and in the following week, to wear gloves. Urine samples were collected at pre-shift and post-shift for the first two consecutive days in each week, and urinary BPA concentrations were measured. In cashiers without gloves, about a two-fold increase in urinary BPA concentrations was observed after work-shift. When the cashiers wore gloves, however, urinary BPA levels showed no changes. Higher urinary BPA concentrations were associated with greater levels of fasting insulin and insulin resistance. Our observation shows that receipt handling among the cashiers could double the BPA exposure levels at post-shift compared to those at pre-shift, and use of simple protective equipment such as gloves could effectively reduce the BPA exposure levels. Keywords: Bisphenol A, Receipt, Cashier, Dermal exposure, Metabolic syndrome

Bisphenol A (BPA) exposure during the perinatal and postnatal periods increases the susceptibility to disease over the life cycle. However, information on the BPA delivered to fetuses or infants via the placenta and breastfeeding is limited. We determined the BPA exposure levels in various bodily fluids and tissues of pregnant women and described fetus and infant exposures to BPA based on associations and BPA ratios in mother-neonate paired samples. Maternal serum, urine, placenta, breast milk, cord serum, and neonatal urine samples were collected from 318 mother-neonate pairs at six university hospitals in Korea. BPA levels were detected using liquid chromatography tandem mass spectrometry. The ratios of the BPA levels in the other sample types to the levels in maternal serum were calculated. BPA was detected in 79.5-100% of the maternal and fetal samples. The median BPA concentration in the samples decreased in the order of neonatal urine (4.75ng/mL), maternal urine (2.86ng/mL), cord serum (1.71ng/mL), maternal serum (1.56ng/mL), breast milk (0.74ng/mL), and the placenta (0.53ng/g). We estimated the ratios of BPA levels in the other sample types to those in maternal serum. The median (95th percentile) cord serum-to-maternal serum ratio was 1.12 (15.2) for 160 mother-fetal pairs, in which BPA was detected in both samples. The placenta-, maternal urine-, neonatal urine-, and breast milk-to-maternal serum ratios were 0.28 (5.31), 1.79 (29.9), 1.98 (28.2), and 0.51 (10.5), respectively. In addition, the median (95th percentile) cord serum-to-placenta ratio was 4.03 (45.8), and the neonatal urine-to-cord serum ratio was 1.95 (25.6). The 95th percentile values were 14-20-fold greater than the medians. Urine contained the highest BPA concentrations, followed by serum, breast milk, and the placenta. The variations of BPA ratio show individual differences in the amounts of BPA delivered from mother to fetus.

Parabens and triclosan have been widely used in many personal care products and cosmetics. The endocrine disrupting potential of these compounds is of increasing public health concern. The aim of this study is to understand the current exposure profile of these chemicals in last void before bedtime (night-time) and first-morning void (first-morning) urines among a Korean population and to characterize their exposure sources and pathways. A total of 261 people, including infants (0–2 years), toddlers (3–6 years), children (7–12 years), adolescents (13–18 years), and adults (≥19 years), were recruited, and sampled for night-time urine and first-morning urine of the following day. Methyl (MeP), ethyl (EtP), propyl (PrP) and butyl paraben (BuP), and triclosan were measured in urine. The demographic characteristics, use of personal care products, and food consumption were obtained through a questionnaire. Among the target compounds, EtP and MeP were most frequently detected at the highest concentrations. The median concentration of EtP in night-time urine was 32.4 μg/L (interquartile range: 8.37–82.8 μg/L), which is higher than previously reported worldwide. Unlike other test compounds, compared to those measured from first-morning urine, the EtP concentrations were significantly higher in night-time urine, suggesting the presence of different exposure sources. Among adults, the MeP and PrP concentrations in night-time urine were associated with frequent use of skin care products, colored cosmetics, bath products, toothpaste, vinyl food packaging, or consumption of canned food. The MeP and PrP concentrations were higher in females than in males, especially in night-time urine. The results of this study also show that multiple urine samples are necessary to capture the diurnal variation of non-occupational exposure to environmental chemicals, such as parabens.

Exposure of the developing fetus and infants to toxic substances can cause serious lifelong health consequences. Several chemicals have been associated with adverse neurodevelopmental disorders in the early life stages of humans. However, most epidemiological studies have focused on a limited number of chemicals, and hence may exclude important chemicals from consideration or result in conclusions built on associations by chance. In the present study, we investigated the chemical exposure profile of the women, and associated these with the early neurodevelopmental performance of their offspring at 13-24months of age. The chemicals assessed include four phthalates, bisphenol A, three heavy metals, 19 polychlorinated biphenyls (PCBs), 19 organochlorine pesticides, and 19 polybrominated diphenyl ethers, which were measured from urine, whole blood, serum, and/or breastmilk of the pregnant or lactating women. For neurodevelopmental performance, the Bayley Scales of Infant Development-II (BSID-II), Social Maturity Scale (SMS), and Child Behavior Checklist (CBCL) were measured from a total of 140 toddlers. Among the measured chemicals, monoethyl phthalate (MEP) in maternal urine was significantly associated with early mental, psychomotor, and social development. In addition, breast milk di-ethylhexyl phthalate (DEHP) metabolite and blood lead concentrations were inversely associated with mental and psychomotor development indices, respectively. Maternal blood PCB153, heavy metals, and urinary MEP levels were also higher among the children with behavioral problems, as indicated by the CBCL range. Taken together, maternal exposure to several EDCs such as PCBs and DEHP was associated with adverse neurodevelopmental performances among the children aged 1-2years. Confirmation of these association in larger populations, as well as longer-term consequences of such exposure warrant further investigation.

Many scientists made estimates of the body burden of PBDEs from breastmilk and house dust. Interestingly, they have not included the prenatal contribution to the body burden in young children after birth. In order to address how the prenatal contribution is important in the risk assessment of PBDEs in infants up to five years old, we used the median measurements of BDE-47 as a model chemical in 108 neonates in Korea, and made simulations of its disposition out of body from birth to five years. During the simulation periods, the environmental exposure was considered for house dust, babyfood, breastmilk consumption, etc., with assumption of typical exposure scenario applicable to general infants in Korea. About 22% of the total amounts of BDE-47 in newborn remained up to 5 years after birth. The relative amounts of BDE-47 from the prenatal source were 20%, 14%, 10%, 8%, 6%, and 4% of the total body burden for 1-, 2-, 3-, 4- and 5-year after birth, respectively. The contribution from breastfeeding was 95.2% and 92.2% of the total postnatal exposure amounts at 6-month and 1-year after birth, respectively. After cease of breastfeeding at 1-yr, house dust and food were the important sources of exposure up to 5-yr; however, their contributions to the bodyburden were negligible with consideration of the remaining amounts of the analytes from the breastmilk and prenatal exposure. Suggestively, the innate amounts and pharmacokinetics should be counted in estimating bodyburden of BDE-47.

Bisphenol S (BPS) has been introduced as a substitute for bisphenol A (BPA), and widely used in the manufacture of polycarbonate plastics, epoxy resins and thermal papers. Despite its adverse health outcomes and widespread exposure, pharmacokinetic data of BPS are not available for either animals or humans. The objective of the study is to describe pharmacokinetic characteristics of BPS in human body after a single oral administration with a compartmental pharmacokinetic model. Seven healthy young adults were orally exposed to 8.75μg/bw of d4-BPS, and serum and urine samples were collected for 48h. The concentrations of total and unconjugated d4-BPS in samples were measured using HPLC-MS/MS. Based on the time-concentration profiles in serum and urine, non-compartmental analysis was performed, and two-compartment model was constructed and validated. As a result of non-compartmental analysis, total d4-BPS was rapidly absorbed within 1h (0.7±0.3h) after oral administration, and excreted in urine with terminal half-life of

Breastfeeding is an important exposure pathway to perfluoroalkyl substances (PFASs) for newborn infants. Nevertheless, reports are limited on the occurrence and time-course of PFASs in breast milk, and most studies have focused on the analysis of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). In this study, 16 PFASs were analyzed in breast milk samples (n=293) collected from 128 mothers in Korea during various lactation periods to assess maternal exposure levels, contamination profiles, time-course variations, and infant health risks. The total concentrations of PFASs (ΣPFAS) ranged from 31.7 to 1004 (median: 188) ng/L, which was within the ranges recently reported for Asian and European populations. After a month of nursing, the concentrations of PFOS, PFOA, perfluorononanoic acid (PFNA), and ΣPFAS significantly increased. This could be due to changes in the dietary and behavior patterns of the mothers after the first month of lactation. The concentrations of PFOS and PFOA were significantly correlated with maternal age, body mass index, and parity. Certain types of diet (e.g. consuming snacks and milk) and eating-out frequency were significantly associated with increasing levels of PFAS. Significant correlations and similar time-course trends were found between PFASs and PCBs/DDTs, implying similar exposure sources and biokinetics for these contaminants. The estimated daily intakes of PFOS and PFOA via the consumption of breast milk were below the tolerable daily intakes for infants suggested by the European Food Safety Authority (EFSA).

Mercury and lead are naturally occurring toxicants and are responsible for various health issues including neurobehavioral and developmental disorders. Because of crucial synchronized developmental processes occurring at the early stage of life, infancy and childhood are considered as among the most susceptible windows to the exposure to these metals. Breastmilk is often the only source of nutrition during the first months of life. As breastmilk can be contaminated with these metals, breastfeeding may serve as a significant route of heavy metal exposure among infants. In order to understand current levels of exposure to mercury and lead through breastfeeding, and their associated risks, a total of 157 lactating mothers were recruited from Children's Health and Environmental Chemicals of Korea (CHECK) cohort, and breastmilk samples were collected at 15 and 30days after delivery (n=207). Mercury was detected from 100% of breastmilk with a median concentration of 0.59μg/L, and lead was detected in 77% of the samples with a median at 4.71μg/L. Higher concentrations of lead were found in the 30- day breastmilk than in the 15-day. Up to 45% of the breastmilk samples exceeded the normal range of the breastmilk lead suggested by WHO. Based on Monte Carlo simulation, about 71% of 15days old infants and 56% of 30days old infants were estimated at risk due to lead exposure through breastfeeding. Considering vulnerability of infants and well-known neurological toxicity of these metals, further studies to identify major exposure sources that contribute the lead concentration in breastmilk and health implication of early life stage exposure to lead among the breastfed infants are warranted.

Background: The environmental health of children is one of the great global health concerns. Exposures in utero and throughout development can have major consequences on later health. However, environmental risks or disease burdens vary from region to region. Birth cohort studies are ideal for investigating different environmental risks. Methods: The principal investigators of three birth cohorts in Asia including the Taiwan Birth Panel Study (TBPS), the Mothers and Children's Environmental Health Study (MOCEH), and the Hokkaido Study on Environment and Children' Health (Hokkaido Study) coestablished the Birth Cohort Consortium of Asia (BiCCA) in 2011. Through a series of five PI meetings, the enrolment criteria, aim of the consortium, and a first-phase inventory were confirmed. Results: To date, 23 birth cohorts have been established in 10 Asian countries, consisting of approximately 70,000 study subjects in the BiCCA. This article provides the study framework, environmental exposure and health outcome assessments, as well as maternal and infant characteristics of the participating cohorts. Conclusions: The BiCCA provides a unique and reliable source of birth cohort information in Asian countries. Further scientific cooperation is ongoing to identify specific regional environmental threats and improve the health of children in Asia.

We evaluated the spatial-temporal dispersion of airborne nanomaterials during the use of spray consumer products and estimated the level of consumer inhalation exposure. A total of eight spray products including five propellant and three pump types were selected to evaluate the dispersion of airborne nanoparticles across time and space in a cleanroom which could control the background particles. Four products were advertised to contain silver and one contained titanium nanoparticles, while three products were specified no ENM but as being manufactured through the use of nanotechnology. We used direct-reading instruments with a thermodesorber unit to measure the particles (number, mass, surface area), as well as filter sampling to examine physicochemical characteristics. Sampling was conducted simultaneously at each location (1 m, near-field; 2, 3 m, far-field) by distance from the source. We estimated the inhaled doses at the breathing zone, and the doses deposited in each part of the respiratory tract using the experimental data and mathematical models. Nanoparticles released from the propellant sprays persisted in the air and dispersed over a large distance due to their small size (1466-5565 particles/cm

Although several studies have conducted maternal transfer of individual PBDE congener in experimental animals, there is a paucity of research on differences in maternal transfer of PBDE congeners. The purpose of the study was to investigate and compare placental and lactational transfer of BDE 47, -209 and its metabolites in rat dam-offspring pairs following repeated administration of BDE 47 and -209. 13C-BDE 47, BDE 209 and its debrominated congeners were detected both in dam serum and offspring body, which indicates that PBDEs can be maternally transferred. In addition, BDE 196 and -197 appeared in offspring body earlier than in maternal serum, which suggests that debromination can be occur in offspring body. BDE 209 increased in both dam and offspring while levels of 13C-BDE 47 was not increased in dam serum. 13C-BDE 47 seems to be stored in breast milk rather than in maternal serum, which can be assumed through the drastic increase of the congener in suckling pups. The magnitude of lactational transfer of the administered congeners was greater than that of placental transfer. And 13C-BDE 47 was relatively more transferred to suckling pups than BDE 209 through breastfeeding.

National biomonitoring program can offer solid scientific evidence on exposure profiles of environmental chemicals at a national level, and provide a snapshot of changing exposure level over time. Therefore, several countries have maintained such programs for developing environmental health policies. The Korean National Environmental Health Survey (KoNEHS) was designed to understand the level of human exposure to environmental chemicals by time and location, and to identify possible sources of such exposure. The 2nd stage of KoNEHS, which was conducted between 2012 and 2014, examined a total of 6478 adult subjects over 19 years of age, and measured 21 environmental chemicals of major policy concern. Compared to the findings from the first stage monitoring (2009–2011), slightly higher levels of blood lead were observed, while those of mercury remained similar. Blood metal concentrations, however, were higher than those reported from national biomonitoring programs of United States, Germany and Canada. The urinary concentrations of phthalates metabolites were lower, but those of t,t-muconic acid and BPA were higher than those reported in the first stage survey. The urinary cotinine level decreased perhaps reflecting general declining patterns of first- and second-hand smoking. The results of the second stage survey were made available for public use since April 2016. Some policy efforts appear to be at least in part effective on mitigating chemical exposure among people, e.g., urinary phthalate metabolites and cotinine, while further confirmations are warranted. In-depth assessments will be conducted to identify vulnerable groups and important exposure pathways.

In an offshore platform, many modules and equipment are placed on the limited space called topside, so that the space should be used efficiently. Furthermore, a sufficient space between equipment should be provided for the operability, maintainability, and safety. To guarantee suitable arrangement design, there are many requirements to be considered such as international codes and standards, including owners’ own requirements. Meanwhile, the arrangement design of an offshore topside tends to rely on experts’ knowledge and experiences. Due to the heavy dependence on experts’ knowledge and experiences, consequently, a different arrangement can be derived according to a personal disposition, in spite of the same requirements. In addition, an unacceptable arrangement can be derived due to the omission of some requirements by a designer. To solve such problems, an expert system for the arrangement design of an offshore topside was proposed based on an arrangement evaluation model (AEM) in this study by expanding the previous study of authors for the arrangement design of a submarine. In addition, an arrangement template model (ATM) was proposed to store various data on the arrangement design of the offshore topside. To evaluate the applicability of the proposed expert system, a prototype program consisting of the AEM and the ATM was also developed here. Finally, this program was applied to a problem of a large FPSO topside. The results showed that the proposed system can be used to evaluate the given alternatives for the arrangement design of the offshore topside.

Exposure to persistent organic pollutants (POPs) during pregnancy is associated with a disruption in thyroid hormone balance. The placenta serves as an important environment for fetal development and also regulates thyroid hormone supply to the fetus. However, epigenetic changes of thyroid regulating genes in placenta have rarely been studied. This study was conducted to evaluate the association between several POP concentrations in maternal serum and DNA methylation of thyroid hormone-related genes in the placenta. The placenta samples were collected from 106 Korean mother at delivery, and the promoter methylation of the placental genes was measured by a bisulfite pyrosequencing. The deiodinase type 3 (DIO3), monocarboxylate transporter 8 (MCT8), and transthyretin (TTR) genes were selected as the target genes as they play an important role in the regulation of fetal thyroid balance. Because people are exposed to multiple chemicals at the same time, a multiple-POP model using principal component analysis (PCA) was applied to evaluate the association between the multiple POPs exposure and the epigenetic change in placenta. In addition, a single-POP model which includes one chemical each in the statistical model for association was conducted.Based on the single-POP models, serum concentrations of p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE) and brominated diphenyl ether-47 (BDE-47) were significantly associated with an increase in placental DIO3 methylation, but only among female infants. Among male infants, a positive association between serum p,p′-DDT and MCT8 methylation level was found. According to the multiple-POP models, serum DDTs were positively associated with DIO3 methylation in the placenta of female infants, while a positive association with MCT8 methylation was observed in those of the male infants. Our observation showed that in utero exposure to DDTs may influence the DNA methylation of DIO3 and MCT8 genes in the placenta, in a sexually dimorphic manner. These alterations in placental epigenetic regulation may in part explain the thyroid hormone disruption observed among the newborns or infants followed by in utero exposure to POPs. Keywords: Developmental origins of health and disease (DOHaD), Epigenetics, Persistent organic pollutant, Thyroid hormone, Multipollutant approach, Placenta

Parabens are commonly used as antimicrobial preservatives in consumer products. Because of their possible endocrine-disrupting activities, their safety has become a public concern. Although pharmacokinetic studies on parabens have been conducted in animals, limited information exists on their pharmacokinetic profiles in humans. In the present study, we determined the pharmacokinetic characteristics of propyl paraben (PP) in humans following a single oral administration of 0.6 mg/kg bw of deuterium labeled-PP. We also conducted experiment with similar design but different exposure amount (2.5 mg/kg bw) to verify the validity of the model to be developed. Blood and urine were collected at several intervals over the course of 48 h to measure levels of PP and its metabolites (conjugates and hydrolysates) in 12 male volunteers. The unconjugated parent compound (free PP), glucuronide and sulfate conjugates, p-hydroxybenzoic acid, and p-hydroxyhippuric acid were measured using HPLC-MS/MS. It was found that PP was rapidly absorbed via ingestion within 2 h and quickly eliminated (terminal half-life, 2.9 h). The fraction of administered dose excreted in the urine was 0.05% for free PP, 8.6% for total PP (free + conjugates), 23.2% for p-hydroxyhippuric acid, and 7.0% for p-hydroxybenzoic acid. Utilizing this pharmacokinetic profile, we successfully constructed a multi-compartment model where the disposition of PP was well described with two compartments and that of its metabolites was explained with first-order reactions. The present pharmacokinetic model provides insights into the kinetic properties of the disposition of PP and its metabolites in humans, and it can be used for risk assessment with biomonitoring of PP. Keywords: Propylparaben, Oral exposure, Pharmacokinetics, ADME, Urinary excretion fraction

Background Several studies have suggested potential links of phthalates to obesity in children and adults. Limited evidence, however, has been available for the relations between diethylhexyl phthalate (DEHP) and obesity-related markers or body mass change in early life. Methods 128 healthy pregnant women were recruited and, after delivery, their newborns’ first urine and umbilical cord blood samples were collected. We measured urinary levels of two DEHP metabolites, mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP). We also measured the levels of leptin, total cholesterol and triglyceride (TG) in cord serum, and used them along with weight, length, head circumference and ponderal index (PI, 100 g/cm 3 ) at birth, as obesity-related markers, and estimated the relations between DEHP metabolites and obesity-related markers using generalised linear models. For the evaluation of body mass increase by early life DEHP exposure, body mass index (BMI) z-score change during 3 months after birth by DEHP metabolites in the first urine samples of the newborns were evaluated using logistic regression. Results DEHP exposure was associated with decrease of PI and increase of TG (PI, β=−0.11, p=0.070 and TG, β=0.14, p=0.027), especially for boys (PI, β=−0.13, p=0.021; and TG, β=0.19, p=0.025). Moreover, DEHP exposure was positively associated with body mass increase during 3 months after birth (change of BMI z-scores, OR=4.35, p=0.025). Conclusions Our findings suggest that DEHP exposure may affect body mass change in early life through changes of obesity-related markers.

Objectives: The aim of this study is to investigate microbial contamination in the school food service environment for the assessment of microbial food safety. Methods: We collected both swab samples from tables and desks and airborne bacterial samples from an elementary school (School A) and a high school (School B). Heterotrophic plate count, total coliform, Staphylococcus aureus, and Bacillus cereus were measured with selective media to quantify microbial concentration. PCR assay targeting 16S rRNA genes was performed to identify the strains of S. aureus and B. cereus isolated. In addition, we made a food service checklist for the locations to evaluate the food service environment. A Wilcoxon test was employed to examine the differences in microbial concentration between before lunchtime and afterwards. Results: Heterotrophic plate counts showed higher levels after-lunch compared to before-lunch at School B. However, levels of S. aureus were higher in the after-lunch period (p

Bisphenol S (BPS) has been increasingly used as a substitute for bisphenol A (BPA), a known endocrine disruptor. Early-life exposure to BPA affects fetal development and the risk of obesity in adolescence and adulthood. However, the effects of fetal exposure BPS in later life are unknown. This study aimed to investigate the effects of prenatal BPS exposure on adiposity in adult F1 mice. Pregnant C57BL/6 N mice were exposed to BPS (0, 0.05, 0.5, 5, and 50 mg/kg/d) via drinking water from gestation day 9 until delivery. Thereafter, two groups of offspring (6 weeks old) were either administered a standard diet (STD) or a high-fat diet (HFD) for 4 weeks until euthanasia. The body weight and gonadal white adipose tissue (gWAT) mass were determined, and the energy expenditure for the adiposity phenotype was computed especially for male mice, followed by histological analysis of the gWAT. Thereafter, the expression levels of adipogenic marker genes (Pparg, Cebpa, Fabp4, Lpl, and Adipoq) were analyzed in the gWAT via reverse-transcription PCR analysis. BPS-exposed male mice displayed apparent gWAT hypertrophy, consistent with the significant increase in adipocyte size in the gWAT and upregulation of Pparg and its direct target genes among HFD mice in comparison with the control mice. These results suggest that prenatal BPS exposure potentially increases the susceptibility to HFD-induced adipogenesis in male adult mice.

Mercury (Hg) has obesogenic properties. However, the associated health outcomes of population-level mercury exposure were unclear. This study investigated the relationships between blood mercury levels and obesity-related outcomes such as hyperlipidemia and elevated liver enzymes. Using the second cycle of the Korean National Environmental Health Survey (n = 6454), we performed logistic regression to examine the effects of Hg on hyperlipidemia and elevated liver enzymes. The blood mercury levels were significantly higher in the hyperlipidemia group (n = 3699, male: 4.03 μg/L, female: 2.83 μg/L) compared to the non-hyperlipidemia group (n = 2755, male: 3.48 μg/L, female: 2.69 μg/L), and high blood mercury levels were associated with an 11% higher risk of hyperlipidemia. The elevated liver enzymes group had higher mean blood mercury levels (n = 1189, male: 4.38 μg/L, female: 3.25 μg/L) than the normal group (n = 5265, male: 3.64 μg/L, female: 2.70 μg/L), and elevated blood mercury was associated with a 35% higher risk of elevated liver enzymes. Moreover, the effect was constant after adjusting for personal medications. These results indicate that mercury exposure is significantly associated with hyperlipidemia and elevated liver enzymes.

Metals have been reported for possible associations with metabolic symptoms, but existing information remains contradictory. In the present study, the association between metal exposure and the met...