Occurrence, time trends, and human exposure of siloxanes and synthetic musk compounds in indoor dust from Korean homes.

Siloxanes and synthetic musk compounds (SMCs) have been widely used as additives in household and personal care products. Humans are easily exposed to siloxanes and SMCs originating from these products through ingestion and dermal absorption of indoor dust. In the present study, indoor dust samples were analyzed for 19 siloxanes (cyclic and linear) and 12 SMCs (polycyclic, macrocyclic, and nitro musks) to assess their occurrence, time trends over time, source, and health risks. A total of 18 siloxanes and 10 SMCs were detected in all indoor dust samples obtained from 2011⎯2021, indicating widespread and long-term contamination. Higher detection frequencies and concentrations were associated with siloxanes and SMCs with higher use and strong resistance against degradation processes. Indoor dust samples were dominated by linear siloxanes (L11-L13), 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-(g)-2-benzopyran (HHCB), musk ketone (MK), and 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN). The frequent use of household and personal care products is likely an important source of siloxane and SMC contamination in indoor environments. The concentrations of siloxanes and SMCs in indoor dust increased from 2011 to 2021, particularly, those of linear siloxanes, reflecting the impact of regulatory actions addressing cyclic siloxanes. The profiles of siloxanes remained stable throughout the study period, whereas those of SMCs shifted from nitro to polycyclic musks. The estimated daily intakes (EDIs) of siloxanes and SMCs arising from ingestion were greater than from dermal absorption of indoor dust. The EDIs of siloxanes and SMCs associated with indoor dust indicated that children are exposed to these pollutants.

Urinary concentrations of organophosphate esters and associated health outcomes in Korean firefighters.

Although firefighters are at an increased risk of occupational exposure to chemicals, such as flame retardants, research on the exposure of Korean firefighters to organophosphate esters (OPEs)-a group of emerging flame retardants-remains limited. Therefore, in the present study, OPE metabolite concentrations in the urine samples of 149 former and current Korean firefighters were measured. Based on the data obtained, the estimated daily intakes (EDIs) of OPEs were calculated. Subsequently, the association between the urinary concentrations of OPE metabolites and the potential determinants of OPE exposure and health outcomes (e.g., obesity and serum lipids) was investigated. We found that bis(1-chloro-2-propyl) phosphate (BCIPP) and bis(2-chloroethyl) phosphate (BCEP) were the most prevalent urinary OPE metabolites, with median concentrations of 2.33 and 1.80 ng/mL, respectively; these concentrations were higher than those reported previously in other countries, such as the USA and China. Moreover, their parent compounds-tris(1-chloro-2-propyl) phosphate (TCIPP) and tris(2-chloroethyl) phosphate (TCEP)-exhibited EDIs of 126 and 94.8 ng/kg bw/day, respectively. Unlike the high detection rate of bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) in other populations, its detection rate in this study was low (6.7%), suggesting regional differences in the exposure pattern of OPEs among countries. Furthermore, occupational characteristics, such as recent participation in firefighting activity, were identified as determinants of the urinary concentrations of OPE metabolites. Total OPE metabolites were inversely associated with body mass index and positively associated with high-density lipoprotein cholesterol. Overall, our findings demonstrate that Korean firefighters are highly exposed to several occupation-related OPEs. Further prospective studies will help elucidate the potential health implications of occupational exposure to OPEs among firefighters.

Simultaneous assessment of organophosphate flame retardants, plasticizers, trace metals, and house dust mite allergens in settled house dust.

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 × 10-3 (2.3) µg/g). The concentrations of OPFRs, plasticizers, and trace metals in SHD were significantly associated with the type and number of electronic appliances and combustion activities. Der f1 was significantly associated with the number of occupants and water penetration. Ventilation, vacuum cleaning, and wet cleaning or dry mopping significantly reduced the levels of most contaminants in SHD. As residents are persistently exposed to a wide array of pollutants, comprehensive and adequate measures are required to prevent potential exposures.

Historical record of legacy and alternative halogenated flame retardants in dated sediment from a highly industrialized saltwater lake in Korea.

Legacy and alternative halogenated flame retardants (HFRs), such as polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), and dechlorane plus (DP), were measured in dated sediments from a highly industrialized lake in Korea. All HFRs were detected in almost all of the sediment depth layers for more than 70 years, indicating a history of long-term contamination. Similar historical trends in PBDEs, 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), and DP were observed in dated sediments, whereas decabromodiphenylethane (DBDPE), and 2-ethylhexyl-2,3,4,5-octabromo-1,3,3-trimethyl-1-phenylindane (OBIND) concentrations sharply increased since the 1990s. Moreover, the concentration ratios of DBDPE/BDE 209 increased from the early 1990s to the present. Our findings suggest that DBDPE and OBIND have been used as HFR alternatives. The historical record of the concentrations and profiles of legacy and alternative HFRs corresponded with industrial activities, consumption of FRs, and coastal development activities. Inventories of legacy and alternative HFRs were similar to those reported for highly industrialized regions around the globe.

Within- and between-person variability of urinary phthalate metabolites and bisphenol analogues over seven days: Considerations of biomonitoring study design.

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.

Assessment of regional and temporal trends in per- and polyfluoroalkyl substances using the Oriental Magpie (Pica serica) in Korea.

Per- and polyfluoroalkyl substances (PFASs) are used in industrial and commercial products due to their amphiphilic properties. Birds have been utilized as biomonitoring species due to their environmental pollutant vulnerability and wide distribution. The Oriental Magpie (Pica serica) is a representative residential species inhabiting terrestrial environments. In this study, we measured PFAS concentrations in Magpie liver tissue (n = 253) collected from 12 Korean regions in 2004 and 2017. The predominant compounds were perfluorooctanesulfonic acid (PFOS; mean: 23.8 ng/g wet weight), perfluorotridecanoic acid (PFTrDA; 2.79 ng/g), and perfluoroundecanoic acid (PFUnDA: 2.11 ng/g). We observed significant correlations between Magpie PFAS measurements, indicating similar sources and bioaccumulation processes. Adult females showed significantly lower PFOS concentrations than adult males and young males and females, indicating that avian sex is a crucial physiological factor of PFAS accumulation. PFOS, perfluorodecanoic acid (PFDA), and perfluorotetradecanoic acid (PFTeDA) concentrations in urban regions were significantly higher than rural regions. PFOS concentrations in Magpie livers increased significantly between sampling years, whereas C11-C13 carboxylic acids (PFCAs) decreased. This suggests that urbanization and population are major factors in Magpie PFAS accumulation. Almost all hepatic PFOS concentrations were below the threshold values proposed by previous studies, implying limited risks. Our findings suggest that the Oriental Magpies are PFAS sentinel in residential environments. This is the first comprehensive report on biomonitoring of PFASs using the Oriental Magpie.

Legacy and novel flame retardants in water and sediment from highly industrialized bays of Korea: Occurrence, source tracking, decadal time trend, and ecological risks.

Legacy and novel flame retardants (FRs) such as polybrominated diphenyl ethers (PBDEs), novel BFRs, and organophosphate flame retardants (OPFRs) were measured in water and sediment collected from highly industrialized bays of Korea. Predominant compounds in sediment were BDE 209, DBDPE, and BTBPE for BFRs, and TCPP and TBOEP for OPFRs, respectively. Higher alternative FR concentrations were observed compared to those reported for previous studies. The highest BFR concentrations were found in locations close to industrial complexes, while the OPFR concentrations were highest in locations close to domestic regions and a wastewater treatment plant. Different contamination sources were observed for BFRs and OPFRs. The ratio of DBDPE/BDE 209 in sediment ranged from 0.84 to 28, indicating a shift in consumption of BFRs. A significant decline in PBDEs suggests the effectiveness of domestic and global regulations. Despite this, sedimentary PBDE concentrations may pose adverse health risks to benthic organisms and humans.

Benefits of social cognitive skills training within routine community mental health services: Evidence from a non-randomized parallel controlled study.

Although social cognitive impairments are evident in patients with schizophrenia across many cultures, psychosocial interventions are less used in Eastern countries. Despite a growing emphasis on community care in mental health services in Eastern countries, the synergistic effects of social cognitive intervention strategies on routine community mental health services are not well documented. This study aimed to adapt a group-based social cognitive skills training (SCST) program for use in a Korean context and evaluate its feasibility and preliminary effects among community-dwelling individuals with schizophrenia. Forty-seven patients were assigned to either the SCST + treatment as usual (TAU) group (n = 21) or the TAU only group (n = 24). Participants completed tasks to assess social cognition, social functioning, neurocognition, and psychiatric symptoms before and after treatment. Over a period of approximately 12 weeks, drop-out rates were comparably low in both groups, and the attendance rates for the SCST program were high (85.7 %, mean sessions attended = 20.56/24 sessions). The SCST + TAU group demonstrated significant improvements in facial affect recognition, social functioning, and psychiatric symptoms compared to the TAU only group. A non-significant trend in theory of mind was observed, along with no improvements in social perception and neurocognition. The adapted version of the SCST program is feasible for implementation and demonstrates promise for enhancing social cognition and functioning in Korean outpatients with schizophrenia.

Exposure to organophosphate esters, phthalates, and alternative plasticizers in association with uterine fibroids.

Exposure to endocrine disrupting chemicals is suggested to be responsible for the development or progression of uterine fibroids. However, little is known about risks related to emerging chemicals, such as organophosphate esters (OPEs) and alternative plasticizers (APs). A case-control study was conducted to investigate whether exposures to OPEs, APs, and phthalates, were associated with uterine fibroids in women of reproductive age. For this purpose, the cases (n = 32) and the matching controls (n = 79) were chosen based on the results of gynecologic ultrasonography among premenopausal adult women in Korea and measured for metabolites of several OPEs, APs, and major phthalates. Logistic regression models were employed to assess the associations between chemical exposure and disease status. Factor analysis was conducted for multiple chemical exposure assessments as a secondary analysis. Among OPE metabolites, diphenyl phosphate (DPHP), 2-ethylhexyl phenyl phosphate (EHPHP), and 1-hydroxy-2-propyl bis(1-chloro-2-propyl) phosphate (BCIPHIPP) were detected in >80% of the subjects. Among APs, metabolites of di-isononyl phthalate (DINP) and di(2-propylheptyl) phthalate (DPrHpP) were detected in >75% of the urine samples. The odds ratios (ORs) of uterine fibroids were significantly higher among the women with higher exposures to tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and tris(2-butoxyethyl) phosphate (TBOEP), di(2-ethylhexyl) terephthalate (DEHTP), DPrHpP, and di-(iso-nonyl)-cyclohexane-1,2-dicarboxylate (DINCH). In addition, urinary concentrations of mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), a sum of five di(2-ethylhexyl) phthalate metabolites (∑5DEHP), and mono(4-methyl-7-hydroxyoctyl) phthalate (OH-MINP) were significantly higher in the cases. In factor analysis, a factor heavily loaded with DPrHpP and DEHP was significantly associated with uterine fibroids, supporting the observation from the single chemical regression model. We found for the first time that several metabolites of OPEs and APs are associated with increased risks of uterine fibroids among pre-menopausal women. Further epidemiological and mechanistic studies are warranted to validate the associations observed in the present study.

Dietary contribution to body burden of bisphenol A and bisphenol S among mother-children pairs.

Due to the health concerns over bisphenol A (BPA), bisphenol S (BPS) has been used as an alternative in greater quantity. Diet is considered as the major source of exposure to bisphenols; however, its contribution to the total body burden has not been fully understood. In the present study, a 3-day dietary intervention was carried out for a group of mother and child(ren) pairs (37 families, 93 subjects), and contribution of the dietary factors to body burden of both bisphenols was investigated. During the intervention, the participants were asked to refrain from the foods in cans and plastic containers, fast foods, and delivery foods. Urinary levels of BPA and BPS were measured before, during, and after the intervention. In addition, the questionnaire survey was conducted for potential contributors to BPA and BPS exposure. Following the intervention, urinary levels of BPA and BPS of the mothers decreased on average by 53.1% (95% CI: -30.0, -68.6), and 63.9% (95% CI: -37.1, -79.3), respectively. Among the children, urinary BPA concentrations decreased by 47.5% (95% CI: -25.6, -62.9) by the intervention. However, BPS levels in urine did not change in the children. Interestingly, urinary BPS concentrations of the children measured during the non-intervention period were greater than those of the mothers in the same period. Consumption frequencies of several food items, e.g., canned foods, take-out drinks, or fast foods, were significantly correlated with elevated levels of urinary BPA or BPS concentrations. The results of this intervention study emphasize the importance of dietary contribution to BPA exposure among the mothers and children. Our findings also show that non-dietary sources could be a more important contributor for certain people, especially to BPS exposure among children. Further studies are warranted to identify the sources of BPS exposure among children.

Legacy and emerging per- and polyfluoroalkyl substances (PFASs) in the coastal environment of Korea: Occurrence, spatial distribution, and bioaccumulation potential.

Contamination by per- and polyfluoroalkyl substances (PFASs) is of great concern in global environments. Due to strong regulation of legacy PFASs, emerging PFASs including alternatives and precursors have been introduced to the industrial market. In this study, legacy and emerging PFASs were measured in seawater, sediment, and bivalves collected along the Korean coast to investigate the occurrence, distribution, contamination sources, and bioaccumulation potential of PFASs. Wide concentration ranges of legacy PFASs were detected in multiple environmental samples, indicating widespread contamination. C8-based PFASs (e.g., PFOA and PFOS) were still major contaminants in all of the environmental samples. Some precursors, such as 8:2 fluorotelomer sulfonate (8:2 FTS) and N-ethyl-perfluorooctane sulfonamidoacetic acid (N-EtFOSAA), and perfluoro-2-propoxypropanoic potassium 9-chlorohexadecafluoro-3-oxanonane-1-sulfonate (F-53B), an alternative to PFOS, were detected in sediment or bivalve samples, implying a shift in consumption patterns from legacy to emerging PFASs. The highest concentrations of PFASs in environmental samples were found at the locations near industrial complexes, such as those for the semi-conductor, paper mill, automobile, and metal-plating industry. This result indicates that PFAS contamination is associated with intensive industrial activities in the coastal environment. Matrix-dependent contamination and profiles of PFASs were observed. Seawater was dominated by short-chained PFASs as a prompt reflection of regulation, while the sediment and bivalves were dominated by long-chained PFASs. Carbon-chain length was a major factor governing environmental behavior and bioaccumulation of PFASs. This was the first nation-wide survey on legacy and emerging PFASs in the coastal environment of Korea.

Phthalates and non-phthalate plasticizers in sediment from Korean coastal waters: Occurrence, spatial distribution, and ecological risks.

Due to regulations on phthalates, non-phthalate plasticizers (NPPs) are now used as an alternative. Limited studies have been conducted on the occurrence and distribution of NPPs. In this study, sediment samples were collected from 50 locations along the Korean coast to assess the occurrence, distribution, sources, and ecological risks of phthalates and NPPs. Phthalates and NPPs were detected in all sediments, indicating ubiquitous contamination of the coastal environment. Di(2-ethylhexyl)phthalate (DEHP) and di(2-ethylhexyl)terephthalate (DEHT) were dominant, suggesting that DEHT could be an emerging contaminant of concern. The highest concentrations of phthalates and NPPs were found in sediment samples from harbors, implying they are contaminated hotspots. Sedimentary organic carbon was a major factor governing the distribution of phthalates and NPPs. Significant correlations were observed among phthalates and NPPs, suggesting similar sources and geochemical behavior. DEHP concentration exceeded threshold values, indicating potential health risks to benthic organisms in sediments.

Occurrence and emission of phthalates and non-phthalate plasticizers in sludge from wastewater treatment plants in Korea.

Phthalates are endocrine-disrupting chemicals that cause adverse health effects in wildlife and humans. Due to domestic and global regulations of phthalates in commercial products, non-phthalate plasticizers (NPPs) have been introduced into industrial markets. Few studies have been conducted on the occurrence of phthalates and NPPs in sludge from wastewater treatment plants (WWTPs). In this study, sludge samples were collected from 40 WWTPs in Korea to investigate the occurrence, compositional profiles, and emission flux of phthalates and NPPs. Total concentrations of phthalates and NPPs in sludge ranged from 4.7 to 1400 (mean: 110) µg/g dry weight and from 0.17 to 780 (mean: 28.0) µg/g dry weight, respectively. Di(2-ethylhexyl)phthalate (DEHP) was a predominant compound, suggesting widespread consumption in Korea. Di(2-ethylhexyl)terephthalate (DEHT) was dominant in industrial sludge samples, whereas di-isononyl cyclohexane-1,2-dicarboxylate (DINCH) and trioctyl trimellitate (TOTM) were dominant in domestic sludge. This implies different consumption patterns of phthalate alternatives by industry and domestic activities. Concentrations of NPPs were significantly correlated with those of high-molecular-weight (HMW) phthalates, indicating that HMW phthalates were preferentially replaced by NPPs. The emission fluxes of phthalates via domestic WWTP activities were higher than those measured for industrial WWTPs, while the emission fluxes of NPPs via industrial WWTPs were higher than those found for domestic and industrial WWTPs. This indicates that phthalate emissions are associated with household activities, while NPP emissions are associated with industrial activities.

Receptor-based aggregate exposure assessment of phthalates based on individual's simultaneous use of multiple cosmetic products.

To estimate realistic exposure to a chemical, the aggregate exposure from multiple consumer products should be considered. A receptor-based aggregate exposure assessment was conducted according to individuals' exposure factors and simultaneous use patterns including co-use and non-use. A product-based aggregate exposure assessment was conducted by product usage rates of population and users' exposure factors. Two aggregate exposure assessments were compared. Exposure factors for 31 cosmetic products were collected by face-to-face interviews with 1001 members of the Korean population through national representative sampling. The concentrations of phthalates in 214 cosmetic products were analyzed by GC-MS-MS. The average aggregate exposure dose (AED) determined by the receptor-based method for di(2-ethylhexyl)phthalate (DEHP), di-n-butyl phthalate (DnBP), and diethyl phthalate (DEP) were 0.68 ±â€¯0.87, 1.08 ±â€¯5.71, and 2.47 ±â€¯9.05 µg/kg/day, respectively. The cosmetics that contributed most to the receptor-based AED were skin care and body care products for DEHP, nail care products for DnBP, and fragrance and hair care products for DEP. The young female group showed the highest exposure. The product-based aggregate exposure assessment method underestimated high exposure but overestimated average exposure for DnBP and DEP. The receptor-based aggregate exposure assessment method would be used to determine high exposure groups.

Bisphenol A exposure through receipt handling and its association with insulin resistance among female cashiers.

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.