Homemade weaning foods as a source of lead and mercury exposure in Korean infants - A dietary risk assessment study.

Lead (Pb) and mercury (Hg) are neurodevelopmental toxicants that pose risks to cognitive and behavioral health. Given early childhood's vulnerability to these metals, understanding their sources and pathways of exposure during infancy is crucial for public health. During the weaning process, infants may be exposed to metals through the baby food they consume. We aimed to assess metal exposure through homemade weaning foods by analyzing 288 samples consumed by 157 Korean infants aged 6-, 9-, 12-, 15-, and 24-27 months. Pb was detected in 65 % of samples, with levels reaching up to 169 ng/g. Notably, 58 % exceeded the Maximum Level (ML) of 10 ng/g, with a median concentration of 14.7 ng/g fresh weight. Total Hg was found in 88 % of samples, with a median concentration of 4.56 ng/g fresh weight. Estimated median daily intakes of Pb and Hg were 0.29 and 0.09 µg/kg/d, respectively. Considering a benchmark dose for Pb (0.5 µg/kg/d by EFSA), 94 % (the margin of exposure <10) of all age groups was estimated to have a potential health concern associated with homemade baby food consumption. For Hg, only 6 % exceeded a hazard quotients of 1 compared to a provisional tolerable weekly intake for Hg (4 µg/kg/week by WHO). This study marks the first direct assessment of daily Pb and Hg intake through homemade baby food among Korean infants. Our findings underscore the urgent need for heightened awareness regarding metal exposure through homemade baby food.

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.

Urinary phthalate metabolites over the first 15months of life and risk assessment - CHECK cohort study.

Phthalates are important group of endocrine disruptors. Infants and young children are susceptible to phthalate exposure. However, information on the phthalate exposure during the early stages of life is very limited. This study was conducted to understand the temporal trend of exposure to major phthalates among infants of Korea during the first 15months after birth, and to estimate associated risks. A total of 286 urine samples were collected from 171 children at 3, 9, 12, or 15months of age, with 77 children sampled for two or more times. Four phthalates, i.e., di(2-ethylhexyl) phthalate (DEHP), di-isobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP), and diethyl phthalate (DEP) were chosen, and their major metabolites were analyzed in the urine. The DEHP metabolites were detected in 100% of the urine samples at relatively higher levels compared to those reported in other countries. The levels of mono-ethyl phthalate (MEP) were generally lower. Urinary concentrations of most phthalate metabolites, especially DEHP metabolites, increased as children grew older. Intra-class correlation coefficients (ICCs) calculated for DEHP metabolites over time were high (0.7-0.8), suggesting persistence of consistent exposure sources during this sensitive period of life. Hazard quotient (HQ) and hazard index (HI) were calculated from daily intake estimates divided by recommended toxicity thresholds. Among the study population, 4, 16, and 26% of the children showed HI >1 at 9, 12, and 15months of age, respectively. DEHP exposure explained most of the risk estimates. Considering vulnerability of young children to endocrine disruption, efforts to identify sources of exposure and to develop appropriate mitigation options are warranted.

Occurrence and exposure assessment of polychlorinated biphenyls and organochlorine pesticides from homemade baby food in Korea.

Data on the residue levels of persistent organic pollutants (POPs) in baby food samples are scarce. This is the first study to explore current contamination status and exposure assessment of organochlorines (OCs), including polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), in baby food from Korea. In this study, the concentrations of OCs were determined in homemade baby food samples (n=100) collected from 6-, 9-, 12- and 15-month-old infant groups. The average concentrations of PCBs, dichloro-diphenyl-trichloroethanes (DDTs), hexachlorocyclohexanes (HCHs) and chlordanes (CHLs) in baby food samples were 37.5, 96.6, 26.0, and 13.2 pg/g fresh weight, respectively. The major compounds were CBs 28, 153, 52, and 33 for PCBs and p,p'-DDE, p,p'-DDT and ß-HCH for OCPs. The contribution of DDTs to the total OC concentrations increased from 30% (6-month-old infants) to 67% (15-month-old infants) with increasing infant age, while the concentrations of PCBs, HCHs and CHLs gradually decreased with increasing infant age, suggesting that highest priority for risk reduction of DDTs. The estimated daily intakes (EDIs) of OCs in Korean infants from baby food consumption were lower than the thresholds proposed by the United States Environmental Protection Agency and Health Canada, implying limited potential health risks. However, considering simultaneous exposure from baby food and breast milk consumption, chlordanes and heptachlor epoxide posed potential health risks. Considering the importance of early development and the vulnerability of infants, it is essential to perform systematic monitoring and management programs of OCs in baby food for risk reduction in Korean infants.

Contamination of polychlorinated biphenyls and organochlorine pesticides in breast milk in Korea: time-course variation, influencing factors, and exposure assessment.

Breast milk is a noninvasive specimen to assess maternal and infant exposure to polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). In this study, 206 breast milk samples were collected from 87 participants during lactation, at <7, 15, 30, or 90 days postpartum in four cities in Korea. The total concentrations of PCBs (ΣPCB) and OCPs (ΣOCP) ranged from

Assessment of dermal exposure to benzene and toluene in shoe manufacturing by activated carbon cloth patches.

OBJECTIVES: The aim of this investigation was to use activated carbon cloth (ACC) patches to study the probability and extent of dermal exposure to benzene and toluene in a shoe factory. METHODS: Inhalation and dermal exposure loading were measured simultaneously in 70 subjects on multiple days resulting in 113 observations. Dermal exposure loading was assessed by ACC patches attached to likely exposed skin areas (e.g. the palm of the hand and abdomen). A control patch at the chest and an organic vapor monitor (OVM) were used to adjust the hand and abdomen patches for the contribution from the air through passive absorption of benzene and toluene on the ACC patches. Systemic exposure was assessed by quantification of unmetabolized benzene (UBz) and toluene (UTol) in urine. RESULTS: Mean air concentrations for the study population were 1.5 and 7.5 ppm for benzene and toluene, respectively. Iterative regression analyses between the control patch, OVM and the dermal patches showed that only a small proportion of the ACC patches at the hand had likely benzene (n = 4; mean 133 microg cm(-2) h(-1)) or toluene (n = 5; mean 256 microg cm(-2) h(-1)) contamination. Positive patches were exclusively observed among subjects performing the task of gluing. Significant dermal exposure loading to the abdomen was detected only for toluene (n = 2; mean 235 microg cm(-2) h(-1)). No relation was found between having a positive hand or abdomen ACC patch and UBz or UTol levels. In contrast a strong association was found between air levels of benzene (p = 0.0016) and toluene (p < 0.0001) and their respective urinary levels. CONCLUSIONS: ACC patches are shown to be a useful technique for quantifying the probability of dermal exposure to organic solvents and to provide estimates of the potential contribution of the dermal pathway to systemic exposure. Using ACC patches we show that dermal exposure to benzene and toluene in a shoe manufacturing factory is probably rare, and when it occurred exposures were relatively low and did not significantly contribute to systemic exposure.