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Background: The biggest concern when using household chemical products is the health risk from inhalation exposure.
Objectives: The purpose of this paper was to provide information necessary for estimating inhalation exposure factors in several countries/organizations and to present some examples.
Methods: We attempted to use PRISMA-ScR for a systematic review, but no major reports were found. We used the Google search function instead to find ‘exposure factor handbook’. As for the results, inhalation exposure factors from South Korea, the United States, Canada, the EU, Australia, Japan, and China were compared.
Results: The basic concept and origin of exposure factors was the US Environmental Protection Agency’s Exposure Factor Handbook. Its latest version is 2011, but several chapters have been updated in 2017, 2018, and 2019. South Korea’s Exposure Factor Handbook was updated in 2019, more recently than those of other countries, and was systematically investigated. In South Korea, the average daily respiratory rate is 14.62 m3/day for adults and 12.73 m3/day for children. It is difficult to compare breathing rate by country because each country divides age groups differently and uses different methods to estimate it. Information on household chemical products, space used, and ventilation rate are in the exposure factor handbook in some countries and not in others. It is not in the handbook in South Korea, but in the notice from the NIER (National Institute of Environmental Research), a sub-regulation of the Chemical Product Safety Act.
Conclusions: The exposure factors registered in South Korea’s exposure factor handbook have been systematically studied and reflect the most recent data. When using data not in the relevant handbook, data from other countries might be applied, but it should be determined whether the nature and quality of the original data have been managed.

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Background: Fragrance substances in consumer products can cause adverse health effects such as contact allergy. In South Korea, consumer chemical products must list 26 known fragrance allergens on product labels when they contain more than 0.01%. Fragrance substances are mostly used in combination, so co-exposure can occur via use of a consumer chemical product. Co-exposure to fragrance allergens may show a synergistic effect on the human body.
Objectives: The aims of the study were to analyze the characteristics of fragrance allergens in consumer chemical products available on public websites and to identify the co-occurrence patterns of fragrance allergens.
Methods: The chemicals in 1,443 ingredient disclosures for consumer chemical products were collected through the Ecolife database. The 26 labelled fragrance allergens were identified by category of consumer chemical product. The co-occurrence patterns of the 26 labelled fragrance allergens were analyzed by frequent pattern mining. The unlabelled fragrance allergens presented by European Union Scientific Committee on Consumer Safety were also identified.
Results: Consumer chemical products contained an average of 5.3±4.2 substances among the 26 labelled fragrance allergens. More than 85% of air fresheners, deodorizing agents, and fabric softeners contained at least one of the 26 labelled fragrance allergens. The most frequently contained fragrance allergens were limonene (50.5%), linalool (49.9%), hexyl cinnamal (34.0%), and citronellol (28.3%). 16.7% of consumer chemical products showed a co-occurrence of limonene, linalool, hexyl cinnamal, and citronellol. Thirty-eight unlabelled fragrance allergens were found in the consumer chemical products, with hexamethylindanopyran (25.2%) being the most frequently contained substance.
Conclusions: The characteristics and co-occurrence patterns of 26 labelled fragrance allergens would be useful information for the management of co-exposure to fragrance allergens in consumer chemical products. It is necessary for attention to be paid to unlabelled fragrance allergens.

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Background: The amount of smoking in adolescence increases with a younger age of smoking initiation and affects physical health. To establish and evaluate smoking-related policies, it is important to determine actual smoking status. Validation of self-reported questionnaires can identify the accuracy of the questionnaire data reflecting smoking status.
Objectives: The purpose of this study was to evaluate the validity of self-reported smoking status and identify factors affecting the accuracy of self-reported smoking in South Korean adolescents.
Methods: This study investigated the consistency between cotinine concentrations and self-reported questionnaire data through the analysis of urine samples collected from 922 adolescents aged 13~18 among the participants of Cycle 3 of the Korean National Environmental Health Survey. Smoking status was classified using the cotinine cut-off point of 39.85 μg/L in adolescents, and factors affecting the accuracy were analyzed through multiple logistic regression analysis.
Results: The smoking rates according to the self-reported questionnaire and cut-off point-based cotinine concentrations among adolescents were 3.1% and 5.1%, respectively. The results found 97.1% consistency between self-reported smokers and smokers according to cotinine concentration. Factors affecting the discrepancy showed a significant relationship, including gender, secondhand smoke, and use of e-cigarettes.
Conclusions: The results can be used as basic data to establish a smoking policy for adolescents through continuous monitoring and improvement of questionnaire items of factors affecting the discrepancy.

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Background: Abandoned metal mines are classified as vulnerable areas with the highest level of soil contamination among risk regions. People living near abandoned metal mines are at increased risk of exposure to toxic metals.
Objectives: This study aimed to evaluate the correlation between soil contamination levels in areas around abandoned metal mine and the blood lead levels of local residents. Moreover, we assess the possibility of using soil contamination levels as a predictive indicator for human exposure level.
Methods: Data from the Survey of Residents around Abandoned Metal Mines (2013~2017, n=4,421) and Investigation of Soil Pollution in Abandoned Metal Mines (2000~2011) were used. A random coefficient model was conducted for estimation of the lower level (micro data) of the local resident unit and the upper level (macro data) of the abandoned metal mine unit. Through a fitted model, the variation of blood lead levels among abandoned metal mines was confirmed and the effect of the operationally defined soil contamination level was estimated.
Results: Among the total variation in blood lead levels, the variation between abandoned mines was 18.6%, and the variation determined by the upper-level factors such as soil contamination and water contamination was 8.1%, which was statistically significant respectively. There was also a statistically significant difference in the least square mean of blood lead concentration according to the level of soil contamination (p=0.047, low: 2.32 μg/dL, middle: 2.38 μg/dL, high: 2.59 μg/dL).
Conclusions: The blood lead concentration of residents living near abandoned metal mines was significantly correlated with the level of soil contamination. Therefore, in biomonitoring for vulnerable areas, operationally defined soil contamination can be used as a predictor for human exposure level to hazardous substances and discrimination of high-risk abandoned metal mines.

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Background: In the case of multiple exposures to different types of heavy metals, such as the conditions faced by residents living near a smelter, it would be preferable to group hazardous substances with similar characteristics rather than individually related substances and evaluate the effects of each group on the human body.
Objectives: The purpose of this study is to evaluate the utility of factor analysis in the assessment of health effects caused by exposure to two or more hazardous substances with similar characteristics, such as in the case of residents living near a smelter.
Methods: Heavy metal concentration data for 572 people living in the vicinity of the Janghang smelter area were grouped based on several subfactors according to their characteristics using factor analysis. Using these factor scores as an independent variable, multiple regression analysis was performed on health effect markers.
Results: Through factor analysis, three subfactors were extracted. Factor 1 contained copper and zinc in serum and revealed a common characteristic of the enzyme co-factor in the human body. Factor 2 involved urinary cadmium and arsenic, which are harmful metals related to kidney damage. Factor 3 encompassed blood mercury and lead, which are classified as related to cardiovascular disease. As a result of multiple linear regression analysis, it was found that using the factor index derived through factor analysis as an independent variable is more advantageous in assessing the relevance to health effects than when analyzing the two heavy metals by including them in a single regression model.
Conclusions: The results of this study suggest that regression analysis linked with factor analysis is a good alternative in that it can simultaneously identify the effects of heavy metals with similar properties while overcoming multicollinearity that may occur in environmental epidemiologic studies on exposure to various types of heavy metals.

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Background: The indiscriminate use of pesticides in Nigeria may have harmful effects on reproductive health of farmers.
Objectives: This study assessed the awareness of reproductive health, serum follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, estradiol, progesterone and sperm characteristics of male farmers occupationally exposed to pesticides.
Methods: Eighty four male farmers were recruited for the study. Structured questionnaire was used to obtain the socio-demographic data. Blood and semen samples were collected from the subjects in the morning for hormonal assays and semen analysis using enzyme linked immunosorbent assay (ELISA) method and SQAV sperm quality analyzer. Data were analyzed using chi square, Student's-t-test, and Regression analysis.
Results: Serum FSH (p<0.01), LH (p<0.005) and Estradiol (p<0.001) were significantly higher while prolactin (p<0.02) and testosterone (p<0.001) were significantly lower among pesticides exposed farmers than nonexposed subjects. Some 34/84 (40.5%) of the pesticides exposed farmers had serum testosterone levels below the lower limit of the reference range. Those with low testosterone levels (p<0.001), also had FSH (p<0.05), LH (p<0.001) and Estradiol (p<0.002) significantly lower than those with normal testosterone levels. The sperm count among pesticides exposed farmers; total motility and percentage morphology were significantly lower than non-pesticides exposed subjects. Some 14/84 (16.7%) of the pesticides exposed farmers had sperm count below 15 million/mL (oligozoospermia). More than 70% of the farmers were not aware of the reproductive health risks associated with pesticides and only 23.8% of the farmers were using protective devices.
Conclusions: Deliberate efforts to improve awareness, knowledge, personal hygiene, and interventions necessary to lessen both pesticides exposure and health risks by adopting safe practices are suggested.

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Public interest has been increasing the focus on the management of exposure to pollutants and the related health effects. This study reviewed exposure assessment methodologies and addressed future directions. Exposure can be assessed by direct (exposure monitoring) or indirect approaches (exposure modelling). Exposure modelling is a cost-effective tool to assess exposure among individuals, but direct personal monitoring provides more accurate exposure data. There are several population exposure models: stochastic human exposure and dose simulation (SHEDS), air pollutants exposure (APEX), and air pollution exposure distributions within adult urban population in Europe (EXPOLIS). A South Korean population exposure model is needed since the resolution of ambient concentrations and time-activity patterns are country specific. Population exposure models could be useful to find the association between exposure to pollutants and adverse health effects in epidemiologic studies. With the advancement of sensor technology and the internet of things (IoT), exposure assessment could be applied in a real-time surveillance system. In the future, environmental health services will be useful to protect and promote human health from exposure to pollutants.

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Background: Epidemiology is a fundamental study of public health, including environmental health, since the features and causes of diseases discovered through epidemiology provide crucial information for developing successful disease prevention strategies.
Objectives: This paper tried to define the role and function of epidemiologic research in the field of environmental health, summarize examples of epidemiological studies with regard to selected environmental health events in South Korea, and address important issues that should be considered when conducting epidemiological research in the future.
Methods: Epidemiological studies of selected environmental health events were reviewed and summarized in terms of their contribution to environmental health in South Korea. Based on the information, important issues were suggested for future epidemiological studies in environmental health.
Results: The role and function of epidemiologic research in the field of environmental health includes the systematic description of the health effects caused by environmental exposure, verification of the causal relationship between environmental exposure and health effects, and provision of background data for conducting prevention strategies and developing policies. A number of epidemiological studies have contributed to characterizing and assessing the environmental risks involved in a series of environmental health events in South Korea.
Conclusions: Important issues for future epidemiological studies may include health effects from chronic low-level environmental exposure, application of analytical epidemiology to elucidate causal relationships, use of exposure/disease/susceptibility biomarkers, accurate reconstruction of past exposure status, cohort recruitment and long-term follow-up, and in-advance surveillance of diseases with environmental causes.

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Background: Chemical emissions in the environment have rapidly increased with the accelerated industrialization taking place in recent decades. Residents of industrial complexes are concerned about the health risks posed by chemical exposure.
Objectives: This study was performed to suggest modeling methods that take into account multimedia and multi-pathways in human exposure and risk assessment.
Methods: The concentration of benzene emitted at industrial complexes in Daesan, South Korea and the exposure of local residents was estimated using the Caltox model. The amount of human exposure based on inhalation rate was stochastically predicted for various activity stages such as resting, normal walking, and fast walking.
Results: The coefficient of determination (R²) for the CalTOX model efficiency was 0.9676 and the root-meansquare error (RMSE) was 0.0035, indicating good agreement between predictions and measurements. However, the efficiency index (EI) appeared to be a negative value at –1094.4997. This can be explained as the atmospheric concentration being calculated only from the emissions from industrial facilities in the study area. In the human exposure assessment, the higher the inhalation rate percentile value, the higher the inhalation rate and lifetime average daily dose (LADD) at each activity step.
Conclusions: Prediction using the Caltox model might be appropriate for comparing with actual measurements. The LADD of females was higher ratio with an increase in inhalation rate than those of males. This finding would imply that females may be more susceptible to benzene as their inhalation rate increases.

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Background: A quantitative structure-activity relationship (QSAR) model was adopted in the Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH, EU) regulations as well as the Act on Registration, Evaluation, etc. of Chemicals (AREC, Republic of Korea). It has been previously used in the registration of chemicals.
Objectives: In this study, we investigated the correlation between the predicted data provided by three prediction programs using a QSAR model and actual experimental results (acute fish, daphnia magna toxicity). Through this approach, we aimed to effectively conjecture on the performance and determine the most applicable programs when designating toxic substances through the AREC.
Methods: Chemicals that had been registered and evaluated in the Toxic Chemicals Control Act (TCCA, Republic of Korea) were selected for this study. Two prediction programs developed and operated by the U.S. EPA – the Ecological Structure-Activity Relationship (ECOSAR) and Toxicity Estimation Software Tool (T.E.S.T.) models – were utilized along with the TOPKAT (Toxicity Prediction by Komputer Assisted Technology) commercial program. The applicability of these three programs was evaluated according to three parameters: accuracy, sensitivity, and specificity.
Results: The prediction analysis on fish and daphnia magna in the three programs showed that the TOPKAT program had better sensitivity than the others.
Conclusions: Although the predictive performance of the TOPKAT program when using a single predictive program was found to perform well in toxic substance designation, using a single program involves many restrictions. It is necessary to validate the reliability of predictions by utilizing multiple methods when applying the prediction program to the regulation of chemicals.

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Background: Disinfection is essential to provide drinking water from a water source. The disinfection process mainly consists of the use of chlorine and ozone, but when chlorine is used as a disinfectant, the problem of disinfection by-products arises. In order to resolve the issue of disinfection by-products, electro-chlorination technology that produces chlorine-based disinfectants from salt water through electrochemical principles should be applied.
Objectives: This study surveys the possibility of optimally producing active chlorine from synthetic NaCl solutions using an electro-chlorination system through RSM.
Methods: Response surface methodology (RSM) has been used for modeling and optimizing a variety of water and wastewater treatment processes. This study surveys the possibility of optimally producing active chlorine from synthetic saline solutions using electrolysis through RSM. Various operating parameters, such as distance of electrodes, sodium chloride concentration, electrical potential, and electrolysis time were evaluated.
Results: Various operating parameters, such as distance of electrodes, sodium chloride concentration, electrical potential, and electrolysis time were evaluated. A central composite design (CCD) was applied to determine the optimal experimental factors for chlorine production.
Conclusions: The concentration of the synthetic NaCl solution and the distance between electrodes had the greatest influence on the generation of hypochlorite disinfectant. The closer the distance between the electrodes and the higher the concentration of the synthetic NaCl solution, the more hypochlorous acid disinfectant was produced.

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Background: The risk of imported infectious diseases has been increasing with the annual rise in the number of international travelers.
Objectives: This study aims to analyze the distribution and characteristics of intestinal bacteria isolated in 2019 from residents of Chungcheongnam-do Province with experience of travelling overseas.
Methods: Twenty-three former overseas travelers with diarrhea were analyzed to detect viruses and bacteria according to the Manual for Detection of Foodborne Pathogens at Outbreaks. Additionally, antibiotic susceptibility tests and 16s rRNA sequencing were performed.
Results: Twenty-five strains of ten pathogens were isolated from 18 samples. Pathogenic E. coli was the most common at 57.7%, followed by Clostridium perfringens (15.4%), Campylobacter spp. (7.7%), and Salmonella spp. (7.7%). The serotype of Salmonella was confirmed as Salmonella Braenderup, II 9,46:g,[m],[s],t:[e,n,x].
Conclusions: It was confirmed that the major enteric bacterial pathogens isolated from overseas travelers in Chungcheongnam-do Province were pathogenic E. coli, as found in other studies. The study on Plesiomonas shigelloides is meaningful in that it is reported as a rare case of infection in Korea. Antibiotic resistance and 16s rRNA analysis were performed, which is expected to provide important basic data for the prevention of traveler’s diarrhea.

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Background: No study has examined the regulatory factors associated with fatal health problems due to the use of humidified disinfectants (HD) in South Korea.
Objectives: This study aimed to identify and discuss the deficiencies and limitations found in the Toxic Chemical Control Acts (TCCA) that failed to prevent the health risk of chemicals in HD products.
Methods: The South Korean TCCA was reviewed focusing on acts in operation from 1994 through the end of 2011, the period when HD was allowed in manufacturing and marketing.
Results: The TCCA was the act intended to regulate the toxicity of chemicals in HD products. We found the TCCA to lack three key legal clauses which would have been essential to controlling the health risk of HD. First, there was the exemption of toxic and hazard testing for existing chemicals, including chloromethylisothiazolinone (CMIT), methylisothiazolinone (MIT), and benzalkonium chloride (BKC). Secondly, there were no articles requiring industry to provide animal inhalation test result for polymers such as polyhexamethylene guanidine (PHMG) and Oligo(2-)ethoxyethoxyethyl guanidine chloride (PGH). Finally, there was a lack of articles on examining the risk of products as well as on addressing changes in the usage of products. These articles were found to be generally provided in the US Toxic Substance Chemical Act (TSCA) and the EU Registration, Evaluation and Authorization of Chemicals (REACH).
Conclusions: In conclusion, the Ministry of Environment of South Korea had not updated key articles for regulating hazardous chemicals, causing large-scale health problems due to HD which had been fundamentally addressed in chemical-related acts in other countries.