Average Exposure Dose Research Articles

Organophosphate ester exposure in nail salons: Health implications for workers

Organophosphates esters (OPEs) have become a preferred alternative in nail polish as plasticizers due to health concerns over previously used additives like dibutyl phthalate. However, the true extent of nail technicians' exposure to OPEs is largely unknown. This study shows that nail salon workers are significant exposed to OPEs, with varied concentrations found in air, dust, masks, and urine. The total concentrations of 11 OPEs in ultrasonic personal air samplers (UPAS) ranged from 251 to 1007 ng/m³, and in air conditioner filter dust from 371 to 14473 ng/g. Triphenyl phosphate (TPHP) was the most abundant compound found in the nail polishes used in these salons. On average, the concentrations of TPHP and diphenyl phosphate (DPHP) in workers' urine after work were 5.2 and 1.8 times higher than those before work, respectively. Two nail salons that had the highest nail polish usage also had very high concentrations of TPHP in surgical masks, dust, and UPAS. TPHP concentrations in workers’ urine after work were 19 and 13 times those before work, respectively, in these two salons. Human internal exposure assessment showed that the average exposure dose of TPHP after work was 1.8 times higher than that before work. On average, use of masks reduced OPEs in urine by 77%. In conclusion, frequent mask replacement is highly recommended, especially in long working circumstances. Without regular replacement, masks may accumulate OPEs from the air, potentially becoming another source of human exposure to OPEs. Therefore, more attention should be paid to the occupational exposure of nail salon workers to OPEs, particularly considering that most practitioners in this industry are young women of reproductive age.

Bioaccessibility characteristics of metals in welding fume and its application in exposure assessment

Objective: To explore the bioaccessibility of the main metal components in welding fume welding fume in simulated lung fluid, and to evaluate the exposure level of each metal component in combination with the EPA inhalation exposure risk assessment model. Methods: In November 2022, the microscopic morphology characteristics of welding fumes were analyzed by scanning electron microscopy, the bioaccessibility of each metal component in lung fluid simulated normal and lung inflammatory states was analyzed by in vitro simulation method, and the exposure level of each metal component was calculated in combination with the EPA inhalation exposure risk assessment model. Results: The main metal components in carbon dioxide gas shielded welding fumes were Fe, Mn, Zn, Ti, Al, Cu, Cr, Cd, Ni and As, and the bioaccessibility in simulated normal lung interstitial fluid was 0.82%-1.84%, 5.07%-9.41%, 4.52%-7.23%, 5.10%-8.67%, 20.48%-29.60%, 5.27%-9.83%, 4.80%-7.56%, 0.07%-1.08%, 6.48%-13.84% and 33.02%-42.81%. The bioaccessibility of the above metal components in the lung fluid under simulated lung inflammation was 14.79%-27.45%, 34.53%-46.11%, 35.31%-59.13%, 16.45%-22.51%, 60.78%-76.51%, 26.58%-34.12%, 15.32%-25.87%, 2.0%-5.7%, 34.77%-43.33% and 71.34%-88.36%, respectively. Compared with the simulated lurg interstitial fluid, the bioaccessibility of metal components in the lung fluid under the simulated inflammatory state was increased, and the difference was statistically significant (P<0.05). The average daily exposure dose Mn in the two simulated lung fluids exceeded the inhalation reference limit (>50 times), and the average daily exposure dose Ti and Cr in the simulated lung inflammation exceeded the reference limit (>1.3 times) . Conclusion: Attention should be paid to the bioaccessibility characteristics of metal components in the exposure level and hazard assessment of welding fumes.

Residual distribution and risk assessment of neonicotinoids in urban green space soils of the pearl river delta, South China: A socioeconomic analysis

Urban green spaces are the soil component in cities that interacts most closely with humans. This study investigated the residues of seven neonicotinoids (NEOs) in soils from urban green spaces within the Pearl River Delta (PRD) region and analyzed the correlation between the residue characteristics and the region's economic development. Notably, we introduced the Nemerow Index method, a comprehensive approach, to quantify the overall pollution level of NEOs in the soil of urban park green spaces and utilized this to assess the cumulative exposure probability risks for different populations in this scenario. We found that: (1) The soil of urban park green spaces exhibited varying degrees of NEOs contamination (Σ7NEOs: N.D.–137.31; 6.25 μg/kg), with imidacloprid and clothianidin constituting the highest proportions (89.46 % and 83.60 %); (2) The residual levels of NEOs in Children's Park were significantly higher than those in community parks within Guangzhou, with an average value of 13.30 μg/kg compared to 3.30 μg/kg; (3) The residual characteristics of NEOs exhibited a positive correlation with regional economic development; specifically, the per capita GDP well correlated with IMIRPF, a summation of seven NEOs in imidacloprid equivalents via relative potency factors (R2 =0.86). Regions with higher economic development typically exhibited elevated IMIRPF levels; (4) The fitted cumulative probability distributions for average daily exposure doses revealed that children's exposure was an order of magnitude higher than adults'. Despite this, the exposure risks for both groups remained within acceptable limits.

Investigation of radiation doses and dose constraint values of nonmedical planned exposure radiation practices in Taiwan

In Taiwan, the Nuclear Safety Commission (NUSC) is the competent authority responsible for ensuring the safety of ionizing radiation operations. In recent years, the NUSC has introduced the concepts of ALARA and dose constraints (as recommended by the International Commission on Radiological Protection), to control the radiation safety of various radiation sources, and to review the protective control measures. Consideration of these concepts can help ensure that industry operators optimize radiation protection in planned exposure situations. This study investigated the occupational exposure of facility operators using nonmedical planned exposure radiation sources in Taiwan. The NUSC provided a sampling roster, and survey respondents were randomly selected. An on-site radiation safety survey was conducted using a calibrated handheld radiation survey meter to measure the doses that radiation workers were exposed to during normal operations. In addition, the dose constraints of multiple radiation practices were evaluated through the statistical analysis of dose data. From 2020 to 2023, on-site radiation dose surveys were conducted on 1614 radiation sources. Additionally, the average occupational exposure doses of workers in relation to multiple nonmedical radiation operations were evaluated, and recommended dose constraints for these operations were proposed.

Occurrence, distribution characteristics and exposure assessment of perchlorate in the environment in China

Recognizing the extent of perchlorate pollution in the environment is critical to preventing and mitigating potential perchlorate harm to human health. The presence and distribution of perchlorate in Chinese environmental matrixes (water, atmosphere, and soil) were systematically investigated and comprehensively analyzed, and cumulative perchlorate exposure at the regional level was assessed using a combined aggregate exposure pathway method. The results showed that perchlorate is ubiquitous in the environment of China with significant regional differences. The total perchlorate exposure levels in each region of China ranked as South China > Southwest China > East China > North China > Northeast China > Northwest China. Although the average exposure dose of 0.588 (95 %CI: 0.142 −1.914) μg/kg bw/day being lower than the reference dose of 0.70 μg/kg bw/day, it was observed that the intake of perchlorate in some regions exceed this reference dose. Oral ingestion was the primary route of perchlorate exposure (89.97–96.57 % of the total intake), followed by dermal contact (3.21–9.16 %) and respiratory inhalation. Food and drinking water were the main sources of total perchlorate intake, contributing 52.54 % and 31.12 % respectively, with the latter contributing significantly more in southern China than in northern China. In addition, perchlorate exposure from dust sources was also noteworthy, as its contribution was as high as 23.18 % in some regions. These findings will improve understanding of the perchlorate risk and serve as a critical reference for policymakers in crafting improved environmental management and risk mitigation strategies in China and other nations.

원자력규제기관활동이 방사선작업종사자의 원자력규제정책 만족도에 미치는 매개효과(mediation effect) 분석

In order to prevent radiation-related disasters for radiation workers, the higher the average radiation exposure dose for each industry, the stronger the regulatory level of nuclear and radiation safety regulatory agencies is for its purpose and relevance. Therefore, nuclear regulatory agencies must apply radiation safety-related licensing and technical standards for nuclear power facilities differently for each type of nuclear business operator depending on the degree of risk of exposure to radiation. From the perspective of a nuclear regulatory agency with limited administrative and financial resources, this study was conducted to efficiently prioritize the regulated sectors of nuclear power operators and promote scientification of regulatory administration by incorporating evidence-based administration. Using the results of the 「2021 Nuclear Safety Survey」 conducted on 2,000 radiation workers, we investigated how radiation workers' satisfaction with nuclear regulation policy changes depending on the activities of nuclear regulatory agencies between independent, mediating, and dependent variables. Direct effects and indirect effects were measured and tested. Four exogenous factors, including the accident response human management system (ERHMS), accident response material management system (ERMMS), in-house safety culture (CISC), and recurrence prevention safety education system (RPSES) for radiation workers subject to nuclear regulation by the nuclear regulatory administrative agency. The regulatory agency activity satisfaction (RAAS), which is a mediating factor, and the endogenous factor 'nuclear energy and radiation safety' regulatory policy satisfaction (NRPS) were set as independent variables, mediators, and dependent variables, respectively. We examined whether the reliability, validity, and correlation between survey items and measurement variables were significant through reliability analysis, correlation analysis, and factor analysis. As a result of multiple regression analysis and structural equation modeling (SEM) mediation effect analysis, the 'activities of regulatory agencies' regarding the accident response human and material management system, in-house safety culture, and accident recurrence prevention education system are related to the nuclear and radiation safety regulatory policy of radiation workers. It was confirmed that it was an influential factor that made a significant difference in satisfaction. When comparing the sizes of standardization coefficients, the sizes of factors affecting satisfaction with nuclear regulation policy are: in-house safety culture (β=0.395), accident response human management system (β=0.080), accident response material management system (β=0.077), Relapse prevention safety education system (β=0.042) appeared in that order. The implications of this study are that the direction of the nuclear safety regulation policy of regulatory agencies that carry out nuclear regulation administration with limited administrative and financial resources is related to the in-house safety culture (CISC) and accident response human management system of nuclear power operators to prevent nuclear and radiation safety accidents. It can be said that it has been verified through quantitative research that strengthening nuclear safety through reinforcement is more effective and efficient

Health assessment based on exposure to microplastics in tropical agricultural soil

Microplastic (MP) pollution of agricultural soils has caused global alarm over its widespread distribution and potential risks to terrestrial ecosystems and human health. This study assessed human health based on exposure to soil MPs through a comprehensive investigation of the factors influencing their occurrence and spatial distribution on Hainan Island, South China. The results showed that the abundance of soil MPs was 1128.6 ± 391.5 items·kg−1, whereas the normalized abundance of MPs based on using a power-law function was 19,261.4 items·kg−1. Regarding the extent of population exposure to agricultural soil MPs, the average daily exposure dose (pADD) model revealed that using mass as an indicator to assess the health risks associated with MP intake is more reliable than using abundance. However, abundance-based exposure assessments are also relevant because MPs with smaller particle sizes are more harmful to human health. Moreover, for adults, the normalized pADD values based on abundance and mass were 1.68E-02 item MPs·kg BW−1·d−1 and 7.23E-02 mg MPs·kg BW−1·d−1, respectively. Although the multidimensionality of MPs should be further aligned and quantified, the preliminary findings of this study contribute to the development of human health risk assessment frameworks for soil MPs.

Fusion imaging for pulmonary artery embolization: impact on fluoroscopy duration and contrast agent exposure.

To assess the impact of fusion imaging guidance on fluoroscopy duration and volume of contrast agent used for pulmonary artery embolization. Thirty-four consecutive patients who underwent pulmonary artery embolization for pulmonary arterio-venous malformation (n = 28) or hemoptysis (n = 6) were retrospectively included. In the experimental group (n = 15), patients were treated using fusion imaging with 2D/3D registration. In the control group (n = 19), no fusion imaging has been used. Fluoroscopy duration and amount of contrast used were measured and intergroup comparison was performed. The average volume of contrast agent used for embolization in the fusion group (118.3 ml) was significantly lower than in the control group (285.3 ml) (p < 0.002). The mean fluoroscopy duration was not significantly different between both groups (19.5 min in the fusion group vs 31.4 min in the control group (p = 0.10)). No significant difference was observed regarding the average X-ray exposure (Air Kerma) (p = 0.68 in the univariate analysis). Technical success rate was 100% for both groups. Fusion imaging significantly reduces contrast medium volumes needed to perform pulmonary artery embolization. The fluoroscopy duration and the X-ray exposure did not vary significantly. CTA-based fusion imaging using 2D-3D registration is a valuable tool for performing pulmonary artery embolization, helpful for planning and guiding catheterization.Compared to the traditional imaging guidance, fusion imaging reduces the volume of contrast agent used.

Occupational lead exposure health risk assessment and heme biosynthesis: A study on batik artisans in yogyakarta, Indonesia

This study aims to assess dermal and inhalation lead exposure levels among batik industry workers and evaluate noncarcinogenic and carcinogenic health risks associated with lead exposure. We investigate potential relationships between lead exposure (dermal average daily dose and inhalation exposure concentration) and the workers' blood hemoglobin levels (Hb), as well as their urinary ALA (u-ALA) concentrations. Additionally, we explore any possible associations between Hb and u-ALA levels among the workers and identify various factors influencing lead exposure levels. A total of 30 workers were recruited for the study. Interviews and exposure sampling were conducted to measure dermal and inhaled lead exposure. Sample analysis methods include XRF for exposure samples, spectrophotometry for u-ALA, and HiCN colorimetric for Hb. Carcinogenic and noncarcinogenic risk assessments, correlation analysis, as well as ANOVA for factors analysis, were performed. The average dermal exposure dose and inhalation exposure concentration of lead were 6.53 ± 3.2 ng/kg/day and 0.021 ± 0.015 μg/m3, respectively. Hazard Index (HI) values for all workers were below 1 (average: 0.372 ± 0.155), indicating no expected noncarcinogenic health effects due to lead exposure. The average Excess Lifetime Cancer Risk (ELCR) was (5.18 ± 3.84) × 10−8, significantly below acceptable limits. Correlation analysis revealed a significant negative correlation between Hb and u-ALA (r = −0.519, p = 0.058 for male workers and r = −0.531, p = 0.034 for female workers), supporting their use as lead exposure biomarkers. The factors analysis demonstrated a significant impact of working conditions on inhalation exposure (p = 0.018), with outdoor workers experiencing lower lead inhalation. This research provides crucial insights into potential dangers faced by batik workers due to lead exposure, emphasizing the importance of targeted interventions. The strong correlation between Hb and u-ALA indicates their combined effectiveness in detecting lead exposure, even at low levels. The study underscores the significance of outdoor work as a protective measure against inhaling heavy metals, such as lead, present in the air. The assessment of health risks associated with lead exposure in the batik industry lays the groundwork for informed decision-making and interventions to protect workers' well-being, particularly in informal sectors workplaces where health risks are often overlooked.

From vaccine to pathogen: Modeling Sabin 2 vaccine virus reversion andevolutionary epidemiology inMatlab, Bangladesh.

The oral poliovirus vaccines (OPVs) are one of the most effective disease eradication tools in public health. However, the OPV strains are genetically unstable and can cause outbreaks of circulating, vaccine-derived Type 2 poliovirus (cVDPV2) that are clinically indistinguishable from wild poliovirus (WPV) outbreaks. Here, we developed a Sabin 2 reversion model that simulates the reversion of Sabin 2 to reacquire a WPV-like phenotype based on the clinical differences in shedding duration and infectiousness between individuals vaccinated with Sabin 2 and those infected with WPV. Genetic reversion is informed by a canonical reversion pathway defined by three gatekeeper mutations (A481G, U2909C, and U398C) and the accumulation of deleterious nonsynonymous mutations. Our model captures essential aspects of both phenotypic and molecular evolution and simulates transmission using a multiscale transmission model that consolidates the relationships among immunity, susceptibility, and transmission risk. Despite rapid Sabin 2 attenuation reversal, we show that the emergence of a revertant virus does not guarantee a cVDPV2 outbreak. When simulating outbreaks in Matlab, Bangladesh, we found that cVDPV2 outbreaks are most likely in areas with low population-level immunity and poor sanitation. In Matlab, our model predicted that declining immunity against Type 2 poliovirus following the cessation of routine OPV vaccination was not enough to promote cVDPV2 emergence. However, cVDPV2 emergencedepended on the average viral exposure dose per contact, which was modeled as a combination of the viral concentration per fecal gram and the average fecal-oral dose per contact. These results suggest that cVDPV2 emergence risk can be mitigated by reducing the amount of infectious fecal material individuals are exposed to. Thus, a combined strategy of assessing and improving sanitation levels in conjunction with high-coverage vaccination campaigns could limit the future cVDPV2 emergence.

Radiation safety and control in dental medical organizations

The authors analyzed the indicators of radiation exposure of dental medical workers of the Samara Region during medical procedures for the period from 2004 to 2019 in comparison with the quantitative dynamics of X-ray diagnostic studies. The main directions for improving the labor conditions of dental medical professionals when working with X-ray diagnostic equipment are de termined. The purpose of the study is to conduct a comparative analysis of indicators of the radiation exposure of dental medical workers of the Samara Region during medical procedures for the period from 2004 to 2019 in order to assess the radiation safety of personnel. The analytical work was carried out to assess the indicators of the average exposure dose in dental medical workers of the Samara Region during medical procedures according to the hygienic radiation certification of the ter ritory of the Samara Region for the period from 2004 to 2019. As part of this study, the number and demand for X-ray diagnostic procedures in dental medical institutions among the population were studied. A retrospective analysis of the dynamics of X-ray examinations and the values of the aver age individual dose of exposure of personnel working with X-ray dental devices in 10 large dental medical institutions of various forms of ownership in the territory of Samara and the Samara Region (S1‑S10) was carried out for the period from 2004 to 2019 based on the annual statistical reporting forms of the organization's hygienic radiation certificate. The decrease in radiation exposure is due to the replacement of outdated equipment with more modern devices, the transition from film types of examination to digital ones, and an increase in the personnel’s literacy in the field of radiation safety, which characterizes the improvement in the radiation safety indicators in dental workers in Samara and the Samara Region.

Exposure to airborne nickel and phenol and features of the immune response mediated by E and G immunoglobulins

Ambient air pollution with potentially allergenic technogenic haptens facilitates occurrence of atopic reactions and creates favorable conditions for future development of allergic pathologies in exposed population. The aim of this study was to estimate formation of an IgE-mediated and IgG-mediated specific immune response to low-molecular chemical compounds introduced into the body by inhalation (nickel and phenol used as examples). The test groups were made of children (n = 99) and adults (n = 57) who lived under exposure to airborne nickel and phenol in levels not exceeding maximum permissible ones (up to 0.7 MPL). The reference groups included children (n = 95) and adults (n = 53) who lived on a conventionally clean territory. In the test groups, average daily exposure doses of airborne nickel and phenol varied between 0.7•10-6 and 9.3•10-6 mg/(kg•day) for children and between 3.5•10-6 and 5.0•10-5 mg/(kg•day) for adults (the doses were created by emissions from a non-ferrous metallurgy plant); this was 1.5–3.0 times higher than the same indicators in the reference groups. Levels of IgG specific to nickel were more than two times higher in the exposed groups; the exposed children had elevated levels of IgG specific to phenol in their blood, practically three times higher than in the reference group (р &lt; 0.05). By using logistic regression models, we established a significant probabilistic cause-effect relation between elevated nickel levels in children’s blood and elevated levels of IgE-specific to nickel (R2 = 0.87; F = 468.58; р &lt; 0.05). The assessment of the odds ratio made it possible to verify the relationship between nickel levels in blood and the increase in the level of IgE specific to nickel in children (OR = 8.96; 95% CI = 2.00–40.15) and in adults from the test group (OR = 3.12; 95 % CI = 1.10–9.40). The study results indicate that exposure to low levels of airborne nickel and phenol induces hypersensitivity to technogenic haptens in the exposed children and adults. Its distinctive features are an IgE-mediated reaction to nickel and IgG-mediated reaction to phenol. Hyperproduction of immunoglobulin E specific to nickel as well as IgG-antibodies specific to phenol in the exposed children and adults reflects levels of exposure to airborne nickel and phenol and is a peculiarity of a hyperactive immune response developing in the analyzed children on the test territory.

Аэрогенная экспозиция никелем и фенолом и особенности иммунного ответа, опосредованного иммуноглобулинами класса E и G

Ambient air pollution with potentially allergenic technogenic haptens facilitates occurrence of atopic reactions and creates favorable conditions for future development of allergic pathologies in exposed population. The aim of this study was to estimate formation of an IgE-mediated and IgG-mediated specific immune response to low-molecular chemical compounds introduced into the body by inhalation (nickel and phenol used as examples). The test groups were made of children (n = 99) and adults (n = 57) who lived under exposure to airborne nickel and phenol in levels not exceeding maximum permissible ones (up to 0.7 MPL). The reference groups included children (n = 95) and adults (n = 53) who lived on a conventionally clean territory. In the test groups, average daily exposure doses of airborne nickel and phenol varied between 0.7•10-6 and 9.3•10-6 mg/(kg•day) for children and between 3.5•10-6 and 5.0•10-5 mg/(kg•day) for adults (the doses were created by emissions from a non-ferrous metallurgy plant); this was 1.5–3.0 times higher than the same indicators in the reference groups. Levels of IgG specific to nickel were more than two times higher in the exposed groups; the exposed children had elevated levels of IgG specific to phenol in their blood, practically three times higher than in the reference group (р &lt; 0.05). By using logistic regression models, we established a significant probabilistic cause-effect relation between elevated nickel levels in children’s blood and elevated levels of IgE-specific to nickel (R2 = 0.87; F = 468.58; р &lt; 0.05). The assessment of the odds ratio made it possible to verify the relationship between nickel levels in blood and the increase in the level of IgE specific to nickel in children (OR = 8.96; 95% CI = 2.00–40.15) and in adults from the test group (OR = 3.12; 95 % CI = 1.10–9.40). The study results indicate that exposure to low levels of airborne nickel and phenol induces hypersensitivity to technogenic haptens in the exposed children and adults. Its distinctive features are an IgE-mediated reaction to nickel and IgG-mediated reaction to phenol. Hyperproduction of immunoglobulin E specific to nickel as well as IgG-antibodies specific to phenol in the exposed children and adults reflects levels of exposure to airborne nickel and phenol and is a peculiarity of a hyperactive immune response developing in the analyzed children on the test territory.

Effects of low doses of gamma radiation on the human body

The purpose of this study was to investigate the incidence of additional cases of malignant neoplasms (MN) in a comparative aspect between the settlement living next to a radioactive waste disposal facility (RWDF) and the indicators of an environmentally clean area of the same territorial unit (region). Evaluation of radiation situation on the residential territory adjacent to the RAW disposal facility in settlement 1, and in settlement 2 (comparison settlement), as well as interpretation of the obtained data was performed in strict compliance with the requirements of regulatory documents specifying requirements to the research object. When performing measurements, the methodology described in the regulatory documents establishing these rules was used: MU 2.6.1.2398-08 "Radiation Monitoring and Sanitary-Epidemiological Assessment of Land Plots for Construction of Residential Buildings, Public and Industrial Buildings with Respect to Radiation Safety". The residents of the settlement 1 were found to be exposed to 3.7 mSv/year, i.e. 54.2% more than the average whole-year exposure dose received by the residents of the settlement 1 from natural background (2.4 mSv/year), which results in excessive risk of MHC development compared to the ecologically clean region. This indicates that excessive risk of MNS can occur even in conditions of radiation background within the considered safe dose of not more than 5 mSv/year. However, this risk is much lower than that from high doses of radiation. This makes it urgent to search for solutions that would allow implementation of the recommendations of the Chief State Sanitary Doctor of Russia regarding reduction of total radiation dose to 1 mSv per year or to develop measures allowing to neutralize harmful effects of radiation exposure on the human body.

Characterizing seasonal dynamics of indoor fungal exposure and its relations with allergic diseases/symptoms of children - A case-control based investigation in residences

While most epidemiological surveys reported the effects of indoor fungi on causing building materials deterioration, air quality problems and health risks on occupants, the temporal variations of indoor fungal exposure and verification of the adverse health effects are still not well understood. This study conducted a case-control survey and multiple measurements in 23 homes (11 case and 12 reference) in different seasons. Seasonal dynamics significantly affect the indoor airborne fungal concentrations, with the highest in summer (1467 ± 751 CFU/m3) and the lowest in winter (462 ± 356 CFU/m3). The proportions for the airborne fungi at respirable size <4.7 μm accounted for 82.8%, 87.9% and 89.8% in summer, autumn and winter respectively, indicating a higher inhalable fraction into the lower respiratory system of children. With the high-throughput sequencing, the Aspergillus was the dominant genus and the Aspergillus_penicillioides was the prevailing species without seasonal differences. While the logistic regression presented positive associations with exposing to high fungal concentrations (aORs >1), no significant differences were found of airborne fungal concentrations and relative abundance of dust fungi between case and reference groups. The average exposure doses by inhalation for reference and case children were higher in summer under sleeping state, about 263 CFU/kg·d and 321 CFU/kg·d. These findings reveal the seasonal dynamical characteristics of household fungi and the associations with children's allergic diseases/symptoms, providing practical information for future health-based guidelines/standards and effective protection measures in buildings.

Impact of Atmospheric Polycyclic Aromatic Hydrocarbons (PAHs) of Falling Dust in Urban Area Settings: Status, Chemical Composition, Sources and Potential Human Health Risks.

The present work is considered to investigate the sources, concentration, and composition of polycyclic aromatic hydrocarbons (PAHs) and associated health risk assessment of road dust in Riyadh City, Saudi Arabia. The study region included an urban area, strongly affected by traffic, a bare and an industrial area. A total of 50 locations were selected for sampling and 16 different PAHs were determined. The concentration of PAHs in road dust and their estimated lifetime average daily dose (LADD) for adults (human) ranged from 0.01 to 126 ng g−1 and 1950 to 16,010 mg kg−1 day−1, respectively. The ADDing was calculated separately for children (>6), teenagers (6−12), and adults (>12) for all PAHs with each collected sample. Moreover, the average daily exposure dose by ingestion (ADDing) and average daily exposure dose by dermal absorption (ADDder) were more in children (<6 years) as compared to teenagers (6−12 years) and adults (>12 years). Likewise, total equivalency factor based on BaP (TEQBaP) calculations pointed out that PAHs having more benzene rings or having high molecular weight showed high TEQBaP as compared to low molecular weight PAHs. The data revealed that the children population is at high risk for asthma, respiratory and cardiovascular diseases, and immunity suppression as compared to adults in the particular area of investigated region. These outcomes of this study can be used to deliver significant policy guidelines concerning habitants of the area for possible measures for controlling PAHs contamination in Riyadh City to protect human health and to ensure environmental sustainability.

Investigation on the cross-infection control performance of interactive cascade ventilation in multi-scenario of winter

With the wide spread of COVID-19, numerous cases demonstrate that proper ventilation method can reduce the cross-infection risk obviously. Interactive cascade ventilation (ICV) as a recently proposed ventilation method, the advantage of indoor environment construction has been proven. However, few studies are conducted to investigate the virus prevention and control characteristics of ICV, which is particularly important under epidemic normalizing. Hence, this study explored and compared the cross-infection control performance of three ventilation strategies, namely mixing ventilation (MV), stratum ventilation (SV), and interactive cascade ventilation (ICV), with a validated CFD model. A typical office was selected as the background scene, where an infected person coughs, sneezes with standing or sitting at different positions. Exposure doses, health infection risk, and disease burden (DB) were employed as the evaluation indicators under different ventilation methods of multi-scenario. The research results indicated that the average aerosol exposure dose among the human respiratory region under ICV was 0.29 g/day, which was reduced by 67 % and 50 % compared with MV and SV. In addition, only in ICV can the health infection risk meets the EPA standard. The average disease health burden for exposed persons under ICV was 0.93 × 10−6 DALYs pppy, which was 37 % and 70 % lower than SV and MV. The findings obtained from this study confirm that ICV performs excellently in reducing the cross-infection risk, providing the theoretical basis for future epidemic prevention and control.

Seasonal and source characteristics of organophosphorus flame retardants in air and house dust in Taiwan residential microenvironments: Implications for young children's exposure and risk assessment using a probabilistic approach

Organophosphate flame retardants (OPFRs) are prevalent in multiple industries. They have gradually replaced brominated flame retardants in recent years. Eleven OPFRs were collected from indoor air and house dust in two primary activity spaces––bedrooms and living rooms. The aim of the present study was to explore the potential sources of, and health risks associated with, OPFR exposure in young children using integrated and probabilistic approaches. The level of 11 indoor air OPFRs (466 ng/m3) in the bedroom was greater than that measured in the living room (379 ng/m3), and these values contrasted with those detected in dust. The air OPFRs in the warmer season were higher than those measured in the cold season; the inverse was true for those detected in house dust. In both activity spaces, the composition profiles indicated that tris(1-chloro-2-propyl)phosphate in indoor air (39%) and tris(2-butoxyethyl)phosphate in house dust (67%) were the dominant congeners. The average daily exposure dose (ADD) of OPFRs via air inhalation and dust ingestion did not differ significantly between preschool and school-aged children or based on sex. The Monte-Carlo-simulated 95th percentile ADD of the OPFRs in dust ingested by preschool children was 1.4 times higher. The OPFR exposure from air inhalation and dust ingestion in Taiwanese children is currently an acceptable non-carcinogenic risk and a negligible carcinogenic risk to Taiwan residents.

Вариация поглощенной дозы облучения дикого кабана, обитающего на территории радиоактивного загрязнения

The article presents the results of the assessment of the absorbed dose rate from incorporated radionuclides of 137Cs and 90Sr in the body of wild boar living in an area with different levels of radioactive contamination. The internal irradiation dose was evaluated for incorporated 137Cs in muscle and 90Sr in bone tissue of wild boar. During the assessment, it was assumed that radionuclides 137Cs uniformly distributed in the tissue and are in equilibrium conditions, and radionuclides are 90Sr concentrated in the bone tissue of the animal, during the year the concentration of radionuclides is assumed to be constant. In total, samples were obtained from 117 wild boar individuals, among which 87 animals were seized in the exclusion zone and 30 in the resettlement zone. From the animal carcass, spot samples of muscle tissue were taken according to 500 ± 50 g, the 137Cs content in the samples was determined for raw, natural mass. The activity of 90Sr in bone tissue was determined by radiochemical method. As a result of the studies, it was found that the average total exposure dose of wild boar seized in the exclusion zone is twice that of animals seized in the resettlement zone (p &lt; 0,05) and amounted to 653,6 ± 73,5 mGy/day for animals harvested in the exclusion zone and 328,8 ± 31,4 mGy/day for wild boar living in the zone resettlement. Analysis of the coefficients of variation showed that the maximum variation is observed among the values of the absorbed dose of radiation from the incorporated 137Cs in animals that were seized in the exclusion zone. The minimum variation rate occurs with respect to the external exposure dose in animals harvested in the resettlement zone. There is no significant difference (p &lt; 0,05) between the median absorbed dose of exposure of wild boars living in the exclusion zone and the resettlement zone. The result of our studies suggests that the density of contamination is not the main factor determining the formation of an animal’s radiation dose.

Analysis of Cosmic Radiation Exposure for Domestic Flight Crews in Korea

Cosmic radiation exposure of the flight crews in Korea has been managed by Radiation Safety Management around Living Life Act under Nuclear Safety and Security Commission. However, the domestic flight crews are excluded from the Act because of relatively low route dose exposure compared to that of international flight crews. But we found that the accumulated total annual dose of domestic flight crews is far from negligible because of relatively long total flight time and too many flights. In this study, to suggest the necessity of management of domestic flight crews’ radiation exposure, we statistically analyzed domestic flight crew’s accumulative annual dose by using cosmic radiation estimation models of the Civil Aviation Research Institute (CARI)-6M, Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS), and Korean Radiation Exposure Assessment Model (KREAM) and compared with in-situ measurements of Liulin-6K LET spectrometer. As a result, the average exposure dose of domestic flight crews was found to be 0.5–0.8 mSv. We also expect that our result might provide the basis to include the domestic flight crews as radiation workers, not just international flight attendants.