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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.