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Background: The association between exposure to extremely low frequency-magnetic fields (ELF-MF) and childhood leukemia has been controversial. There is a need to clarify this relationship by summarizing key conclusions from systematic review articles.
Objectives: The major aim of this study is to summarize key conclusions from systematic review articles on the association between exposure to ELF-MF and childhood leukemia based on childhood exposure to ELFMF, proximity from childhood household to high voltage cables, and parental occupational exposure to ELFMF.
Methods: This study was conducted through a brief literature review focusing on systematic, meta-analysis, and pooled analysis methods. We conducted a literature search in PubMed using the key words “ELF-MF” and “childhood leukemia” singly or combined.
Results: In 2002, the World Health Organization (WHO)’s International Agency for Research on Cancer (IARC) reviewed two manuscripts to conduct pooled analysis and concluded that there is a significant association between exposure to >0.3 μT or 0.4 μT and childhood leukemia. We found a total of four manuscripts for systematic or pool analysis that have been published since the IARC’s conclusion. They consistently concluded that there was a significant association between exposure to >0.4 μT and childhood leukemia compared to ELF-MF exposure to below 0.1 μT. The proximity of children’s households to high voltage cable lines and occupational exposure by their parents to ELF-MF during certain periods prior to or during pregnancy were inconsistently associated with childhood leukemia. The study found that many EU countries have implemented precautionary policies to prevent potential childhood leukemia due to exposure to ELF-MF.
Conclusions: This study recommends implementing a precautionary policy that includes legal exposure limits for ELF-MF to minimize exposure to ELF-MF.

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Background: Along with the increase in consumer interest in and consumption of tattoo products, the controversy over harmful heavy metals associated with the use of tattoo cosmetics is also increasing. Therefore, investigation of hazardous metals in these tattoo products is needed.
Objectives: This study was performed to provide useful data for establishing reasonable standards to securely manage tattoo cosmetics, tattoo stickers, and tattoo inks distributed in the market.
Methods: Thirteen kinds of hazardous metal contents (Pb, As, Cd, Sb, Ni, Co, Cu, Cr, Se, Ba, Zn, Sn, and Hg) were analyzed for 23 tattoo cosmetics, ten tattoo stickers, and 16 tattoo inks. Hg was measured through the combustion-gold amalgamation method, and other hazardous metals were measured by inductively coupled plasma-mass spectrometry (ICP-MS) after acidic decomposition using a microwave apparatus.
Results: The detected ranges of Pb, As, Cd, Sb, Ni, and Hg in tattoo cosmetics were 0.07~1.18, 0.06~0.41, ND~0.07, 0.01~3.44, 0.12~2.75, and ND~0.01 μg/g, respectively. All of the hazardous metals detected were below the recommended maximum standards of the Ministry of Food and Drug Safety. The mean amount of Pb detected in tattoo stickers for children was 0.24 μg/kg and Cd was not detected, meaning both metals met the recommended criteria. There was no statistically significant difference in all measured metals between children’s tattoo stickers and adults’ tattoo stickers. In the results of the study on the hazardous metal content of tattoo inks, four products (25%) for Pb, one product (6%) for As, 13 products (81%) for Ni, four products (25%) for Cu, and five products (31%) for Zn exceeded the recommended standards approved by the government. The highest predicted exposure amount for hazardous metals exceeding the recommended level of tattoo inks in a single tattooing was 5.69 μg/kg for Ni, 8.51 μg/kg for Zn, 0.44 μg/kg for Pb, 8.07 μg/kg for Cu, 0.44 μg/kg for As, and 71.36 μg/kg for Ba.
Conclusions: It is necessary to prepare criteria for content limitation for the management of Co, Cr, Ba and Se tattoo cosmetics, and tattoo inks require thorough quality control.

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Background: Exposure to volatile organic compounds (VOCs) can have acute and chronic health effects on human beings in general and in working environments. In particular, VOCs are often emitted in large quantities in industrial settings. In such circumstances, there is a need to improve the indoor air quality at workplaces.
Objectives: The purposes of this study were to verify the effectiveness of air cleaning devices in workplaces and provide alternative solutions for improving working environments.
Methods: Personal exposure and area level of VOCs for workers were evaluated in a car-part adhesive process before and after installing an air cleaning device with a TiO2-coated filter. Passive samplers and direct reading instruments were used to collect and analyze the VOCs, and the removal efficiency and improvement of air quality were evaluated. We also calculated the exposure index (EI) to assess the risk level in the workplace.
Results: The removal efficiency for VOCs through the installation of the air cleaning device was approximately 26.9~69.0% as determined by the concentration levels before and after installation. The measured substances did not exceed the exposure limits for the work environment and the EI was less than 1. However, carcinogenic substances such as benzene, formaldehyde, carbon tetrachloride, and trichloroethylene were detected.
Conclusions: The application of an air cleaning device can be a solution for controlling the indoor air quality in a workplace, particularly in cases where ventilation systems cannot be installed due to process limitations.

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Background: Organophosphorus flame retardants (OPFRs) are a group of chemical substances used in building materials and plastic products to suppress or mitigate the combustion of materials. Although OPFRs are generally used in mixed form, information on their mixture toxicity is quite scarce.
Objectives: This study aims to elucidate the toxicity and determine the types of interaction (e.g., synergistic, additive, and antagonistic effect) of OPFRs mixtures.
Methods: Nine organophosphorus flame retardants, including TEHP (tris(2-ethylhexyl) phosphate) and TDCPP (tris(1,3-dichloro-2-propyl) phosphate), were selected based on indoor dust measurement data in South Korea. Nine OPFRs were exposed to the luminescent bacteria Aliivibrio fischeri for 30 minutes and the human hepatocyte cell line HepG2 for 48 hours. Chemicals with significant toxicity were only used for mixture toxicity tests in HepG2. In addition, the observed ECx values were compared with the predicted toxicity values in the CA (concentration addition) prediction model, and the MDR (model deviation ratio) was calculated to determine the type of interaction.
Results: Only four chemicals showed significant toxicity in the luminescent bacteria assays. However, EC₅₀ values were derived for seven out of nine OPFRs in the HepG2 assays. In the HepG2 assays, the highest to lowest EC₅₀ were in the order of the molecular weight of the target chemicals. In the further mixture tests, most binary mixtures show additive interactions except for the two combinations that have TPhP (triphenyl phosphate), i.e., TPhP and TDCPP, and TPhP and TBOEP (tris(2-butoxyethyl) phosphate).
Conclusions: Our data shows OPFR mixtures usually have additivity; however, more research is needed to find out the reason for the synergistic effect of TPhP. Also, the mixture experimental dataset can be used as a training and validation set for developing the mixture toxicity prediction model as a further step.

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Background: Excessive alcohol consumption is at the root of serious social problems such as hangovers, liver dysfunction, and alcoholism.
Objectives: This study was carried out to determine the hangover ameliorating effect of fermented rice extract and a combination of yeast-fermented powder and lysate containing aldehyde dehydrogenase (ALDH) (improved new ingredients) in an ethanol-induced rat study.
Methods: The concentrations of alcohol, acetaldehyde, and malondialdehye in serum were evaluated to assess the anti-alcohol and anti-aldehyde hangover effect in two experiments, one with fermented rice extract) and a second with yeast-fermented powder and lysate, using animal studies.
Results: Experiment 2 with yeast-fermented powder and lysate containing ALDH showed similar and higher activity, respectively, in reducing ethanol and acetaldehyde concentration compared with Experiment 1 with fermented rice extract. Experiment 2 also significantly reduced malondialdehyde, a type of lipid peroxide. The ALDH-related compound (ARC) lysate showed better hangover relief effect than ARC powder.
Conclusions: These results indicate that ALDH-related compounds exhibit a hangover relief effect, and fermented lysate is considered to be a better candidate for hangover relief.

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Background: When particles are absorbed into the human body, they penetrate deep into the lungs and interact with the tissues of the body. Heavy metals in PM_2.5 can cause various diseases. The main source of PM_2.5 emissions in South Korea’s atmosphere has been surveyed to be places of business.
Objectives: The concentration of heavy metals in PM_2.5 near the Ulsan Industrial Complex was measured and a health risk assessment was performed for residents near the industrial complex for exposure to heavy metals in PM_2.5.
Methods: Concentrations of heavy metals in PM_2.5 were measured at four measurement sites (Ulsan, Mipo, Onsan, Maegok) near the industrial complexes. Heavy metals were analyzed according to the Air Pollution Monitoring Network Installation and Operation Guidelines presented by the National Institute of Environmental Research. Among them, only five substances (Mn, Ni, As, Cd, Cr⁶⁺) were targeted. The risk assessment was conducted on inhalation exposure for five age groups, and the excess cancer risk and hazard quotient were calculated.
Results: In the risk assessment of exposure to heavy metals in PM_2.5, As, Cd, and Cr⁶⁺ exceeded the risk tolerance standard of 10^–6 for carcinogenic hazards. The highest hazard levels were observed in Onsan and Mipo industrial complexes. In the case of non-carcinogenic hazards, Mn was identified as exceeding the hazard tolerance of 1, and it showed the highest hazard in the Ulsan Industrial Complex.
Conclusions: This study presented a detailed health risk from exposure to heavy metals in PM_2.5 by industrial complexes located in Ulsan among five age groups. It is expected to be utilized as the basis for preparing damage control and industrial emission reduction measures against PM_2.5 exposure at the Ulsan Industrial Complex.

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Background: The use of heated tobacco products (HTP) causes many adverse health effects. Although the use of HTP by adolescents is prevalent worldwide, research related to it is very limited. There is a considerable lack of research related to the current HTP use rather than ever-HTP use. In particular, research related to predictive factors for current HTP use in adolescents is scarce.
Objectives: The purpose of this study was to analyze related characteristics according to the current use of HTP among South Korean adolescents.
Methods: This was a cross-sectional study that used data from the Seventeenth Korean Youth Risk Behavior Web-based Survey (KYRBWS). A total of 54,848 students in 2021 were included in this study. Chi-squaretest, multiple logistic regression analysis, and chi-square test for trend were used for analyzing related characteristics according to use of HTP.
Results: Overall, 715 (1.3%) students responded as having used HTP during the last 30 days among the 54,848 students. It was found that residence type, subjective body type recognition, subjective health recognition, alcohol use, habitual drug experience, close friend current smoking, and conventional cigarette smoking were significantly associated characteristics with the current use of heated tobacco products. Comparing ‘very thin recognition’ with ‘very fat recognition’, the adjusted odds ratio (OR) was 1.93 (95% confidence interval [CI]: 1.29~2.87) for current use of HTP. Additionally, comparing ‘very unhealthy recognition’ with ‘very healthy recognition’, the aOR was 3.82 (95% CI: 2.40~6.07) for current use of HTP.
Conclusions: Based on these results, residence type, subjective body type recognition, subjective health recognition, alcohol use, habitual drug experience, close friend current smoking, and conventional cigarette smoking were associated with significantly increased odds of current HTP use. Therefore, the results of this study can provide useful evidence about adolescent behaviors in predicting current HTP use.

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Low-dose radiation exposure has received considerable attention because it reflects the general public’s type and level of exposure. Still, controversy remains due to the relatively unclear results and uncertainty in risk estimation compared to high-dose radiation. However, recent epidemiological studies report direct evidence of health effects for various types of low-dose radiation exposure. In particular, international nuclear workers’ studies, CT exposure studies, and children’s cancer studies on natural radiation showed significantly increased cancer risk among the study populations despite their low-dose radiation exposure. These studies showed similar results even when the cumulative radiation dose was limited to an exposure group of less than 100 mGy, demonstrating that the observed excess risk was not affected by high exposure. A linear dose-response relationship between radiation exposure and cancer incidence has been observed, even at the low-dose interval. These recent epidemiological studies include relatively large populations, and findings are broadly consistent with previous studies on Japanese atomic bomb survivors. However, the health effects of low-dose radiation are assumed to be small compared to the risks that may arise from other lifestyle factors; therefore, the benefits of radiation use should be considered at the individual level through a balanced interpretation. Further low-dose radiation studies are essential to accurately determining the benefits and risks of radiation.

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Background: The need to develop alternative chemicals is increasing worldwide due to the strengthening of global chemical regulations and consumer safety awareness in the marketplace.
Objectives: We aimed to review domestic and foreign technology trends for exploring alternative candidate algorithms that can be used to develop safer alternatives to strengthen global market competitiveness and protect public health in the future.
Methods: We searched the current status of research trends, companies related to the development of alternative chemicals in domestic and foreign countries. For this, we referred to research papers and websites by companies and institutes related to such alternatives.
Results: Among the domestic and foreign research trends, more studies in South Korea were focused on predicting molecular-based physicochemical properties and toxicity than were reporting on research exploring alternative candidates. Three web-based databases and six tools were being developed. More studies in other countries predicted information to consider in alternative development than reported on research exploring alternative candidates, and four web-based databases and three tools were being developed. Among the companies related to the development of alternative chemicals, 286 alternatives classified as ‘EVALUATED ALTERNATIVE’ in MARKETPLACE accounted for the most significant proportion in Europe on a continent basis, and the largest number in the United States (US) on a national basis. In South Korea, only significant companies were registered.
Conclusions: In this study, it was found to be necessary to provide public technology support platforms to explore alternative candidates considering various aspects in order to support alternative development. In conclusion, exploring alternative candidate algorithms could contribute to the response to the global trends in the chemical industry and to supporting companies and researchers developing safer alternatives in the future.

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Background: The existing research results on the combined toxicity of these pollutants using mammals, such as rodents, are insufficient, especially in relation to changes in the immune system.
Objectives: This study aims at evaluating the cellular immune response to PE-MPs solely or when combined with Pb, which possess excellent adsorption capacity with PE-MPs and is commonly co-exposed in our daily lives.
Methods: The study investigated the cellular immune function of 9-week ICR mice with 28 days exposure to PE-MPs (2 mg/mouse/day) and Pb (0.1 mM in distilled water) individually and in combination. PE-MPs were administered via gastric intubation while the lead intake was conducted via the oral drinking water route. Cellular immunity was evaluated by analyzing the production for T_H1 cytokines namely, TNF-α and IFN-γ and T_H2 cytokines, IL-4 and IL-6 in culture supernatants from polyclonally activated splenic mononuclear cells ex vivo.
Results: Both the PE-MPs only and the PE-MPs+Pb exposure group revealed an increased T_H1 response with elevated TNF-α and IFN-γ levels and downregulated T_H2 response with low IL-4, and IL-6 production levels compared to the control group. Furthermore, an increased IFN-γ/IL-4 ratio was found in the PE-MPs only and PE-MPs+Pb exposure groups, which indicated the skewedness to T_H1 response. Meanwhile, reduced blood hemoglobin levels and increased levels of IL-4, the dominant T_H2 cytokine in the Pb-only exposure group, were observed.
Conclusions: Our current findings on the predominance of T_H1 immune response in the PE-MPs and PE-MPs+Pb groups suggest that PE-MPs could be responsible for the predominant induction of the cellular immune changes. This finding could be used as an important landmark in research related to T_H1 predominance, such as autoimmune diseases. It suggests that additional research on immune modulation using longer exposure durations or the same exposure route is required to elucidate stronger findings.

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Background: Among various pollutants, fine particle (PM_2.5, defined as particle less than 2.5 nm in aerodynamic diameter) shows the most consistent association with adverse health effects. There is scientific evidence documenting a variety of adverse health outcomes due to exposure to PM_2.5.
Objectives: This study aims to assess the health benefits of that would be achieved by meeting the World Health Organization’s air quality guidelines for PM_2.5 using AirQ+ and BenMAP.
Methods: We estimated PM_2.5 related health benefits in Korea from implementing the World Health Organization’s air quality guidelines (annual average 5 μg/m³ and 10 μg/m³) and Korea’s National Ambient Air Quality Standard (annual average 15 μg/m³). We used World Health Organization’s AirQ+ and U.S. Environmental Protection Agency’s Environmental Benefits Mapping and Analysis Program.
Results: The annual number of avoided PM_2.5 related premature deaths exceeding WHO guideline levels was assessed using both AirQ+ and BenMAP. We estimated that the health benefits of attaining the World Health Organization’s air quality guidelines for PM_2.5 (annual average 5 μg/m³) would suggest an annual reduction of 26,128 (95% confidence interval [CI]: 17,363~34,024) and 26,853 (95% CI: 18,527~34,944) premature deaths.
Conclusions: Our study provided useful information to policy makers and confirms that the reduction of PM_2.5 concentration would result in significant health benefits in Korea.

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Background: Paraben is a widely used substance with a preservative effect found in various materials such as food, medicine, personal care products, and cosmetics.
Objectives: This study was conducted to identify the level of urinary paraben concentrations (i.e., methyl-, ethyl-, and propyl-) among Korean adults and to explore the factors related with the exposure levels.
Methods: We analyzed the third period (2015~2017) of the Korean National Environmental Health Survey (KoNEHS). R statistical software (version 4.1.1) was used to estimate representative values for the whole population with weight variables to reflect sampling design. Whether urinary concentrations tended to increase as the level of paraben exposure-related characteristics increased was tested and P_trend was calculated using general linear models.
Results: Urinary concentrations of all three parabens (i.e., methyl-, ethyl- and propyl-) were higher in women than in men (P_trend<0.0001, 0.008, and <0.0001), and the values of methylparaben and propylparaben tended to increase as the age of subjects increased (P_trend<0.0001, and <0.0001). Urinary concentrations of methylparaben and propylparaben were associated with intensity of exercise (P_trend<0.001, and 0.004), and that of propylparaben was higher in non-smokers (P_trend=0.01). In terms of paraben exposure-related variables, urinary concentrations of parabens (i.e., methyl-, ethyl- and propyl-) increased as the daily average frequency of teeth-brushing (P_trend<0.0001, 0.03 and 0.0001), the frequency of use of hair products (P_trend=0.005, 0.05 and 0.04), the frequency of use of makeup products (P_trend<0.001, 0.001 and <0.001), and the frequency of use of antibacterial products (P_trend=0.005, 0.02 and 0.02) increased.
Conclusions: In our study, urinary concentrations of all three parabens are associated with gender, teethbrushing, hair products, make-up products, and antibacterial products. Methyl- and proyl-parabens were associated with age and intensity of exercise, and propyl-paraben was associated with smoking.

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Background: Few studies have assessed exposure to chemicals in the context of environmental vulnerability with a focus on exposure among populations living in certain geographical areas.
Objectives: This study aimed to investigate cadmium exposure levels and kidney damage indices in environmentally and socioeconomically vulnerable populations, with further subgrouping according to economic status.
Methods: Four areas were selected to represent geographical vulnerability (two environmentally vulnerable populations and two socioeconomically vulnerable populations). Among them, population groups with lower socioeconomic status (SES) were separately classified. Urinary cadmium (UCd), beta₂-microglobulin (β₂-MG), and N-acetyl-β-D-glucosaminidase (NAG) levels were analyzed in samples from 245 residents of these four areas.
Results: Geometric means of concentrations of UCd (0.97~2.02 μg/g creatinine) in all selected populations (N, 245; mean age, 67.8~70.9 years old) were higher than the national reference values (0.39 for adults and 0.78 μg/g creatinine for people in their 60s). Participants with a lower SES had higher UCd and NAG concentrations than did non-low SES participants. In the lower SES group, there was a significant association between UCd and NAG concentrations; however, there was no such correlation in the non-low SES group.
Conclusions: Consistent with the findings of previous studies evaluating chemical exposure and associated health effects in specific populations, the findings of this study suggest that individuals with a low SES may be more vulnerable to exposure and related health effects.