Tear Fluid as a Matrix for Biomonitoring Environmental and Chemical Exposures.

PURPOSE: Exposures to hazardous chemicals have been linked to many detrimental health effects and it is therefore critical to have effective biomonitoring methods to better evaluate key environmental exposures that increase the risk of chronic disease and death. Traditional biomonitoring utilizing blood and urine is limited due to the specialized skills and invasiveness of collecting these fluid samples. This systematic review focuses on tear fluid, which is largely under-researched, as a promising complementary matrix to the traditional fluids used for biomonitoring. The objective is to evaluate the practicability of using human tear fluid for biomonitoring environmental exposures, highlighting potential pitfalls and opportunities. RECENT FINDING: Tear fluid biomonitoring represents a promising method for assessing exposures because it can be collected with minimal invasiveness and tears contain exposure markers from both the external and internal environments. Tear fluid uniquely interfaces with the external environment at the air-tear interface, providing a surface for airborne chemicals to diffuse into the ocular environment and interact with biomolecules. Tear fluid also contains molecules from the internal environment that have travelled from the blood to tears by crossing the blood-tear barrier. This review demonstrates that tear fluid can be used to identify hazardous chemicals from the external environment and differentiate exposure groups.

Optimization of benzene exposure risk assessment: An integrated approach utilizing internal and external concentrations with a focus on biomarkers S-PMA & t, t-MA.

In the majority of occupational settings within China, the concentrations of benzene are observed to fall markedly below the demarcated detection thresholds. Employing traditional risk assessment models, the presence of exceptionally low airborne benzene exposure concentrations may infuse heightened degrees of uncertainty. Consequently, the necessity arises to investigate risk assessment methodologies more apt for the prevalent exposure environment among employees. In the present study, a pharmacokinetic model premised on urinary benzene metabolites (S-PMA and t, t-MA) was employed to ascertain a more precise daily airborne benzene exposure concentration per individual. This value was integrated into the linear multistage model as the 'internal exposure concentration'. In conjunction with the U.S National Environmental Protection Agency's (EPA) inhalation risk assessment model predicated on the external exposure concentration, the Singapore Ministry of Manpower's (MOM) model, and the linear multistage (LMS) model, the carcinogenic and non-carcinogenic effects of benzene were evaluated for 1781 benzene-exposed employees across 76 enterprises in Jiangsu Province. Findings suggest that in the linear multilevel model assessment, the cancer risk levels based on t, t-MA and S-PMA were higher in the printing and recording media reproduction industry, automobile manufacturing industry, general equipment manufacturing industry and the furniture manufacturing industry (median 2.842 × 10-4, 2.819 × 10-4, 2.809 × 10-4, and 2.678 × 10-4), which align more consistently with the actual benzene exposure circumstances of each industry's study participants, with overall risk levels calculated by the linear multistage model exceeding those of the EPA inhalation risk assessment model and the MOM model. This implies that the linear multistage model of internal exposure, based on the reciprocal of benzene biomarkers S-PMA and t, t-MA for airborne benzene exposure, presents enhanced sensitivity and suitability for the current occupational health risk assessment of workers. Without doubt, biomarker-based benzene exposure risk assessment emerges as the optimal choice.

What are exposure biomarkers of rare earth elements for the ionic rare earth occupational population?

Rare earth elements (REEs) are widely utilized in industries. However, The specific exposure features of REEs and potential biomarkers of exposure in occupational populations remain unclear. In this study, we evaluated the external and internal REEs exposure levels among the participants working in the ionic rare earth smelting plant. For the external exposure, the concentrations of 14 REEs and total rare earth elements (ΣREEs) in airborne particles were significantly elevated in the REEs-exposed versus non-exposed group (P < 0.05). Meanwhile, the levels of Yttrium (Y), Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy), Holmium (Ho), Thulium (Tm), Ytterbium (Yb), and ΣREEs in urine were higher in the REEs-exposed group compared to the non-exposed group (P < 0.05). Notably, a significant positive correlation was observed between Y in both the airborne particles and urine samples as well as Gd, and the Spearman correlation coefficient was 0.53 and 0.39 respectively, both P < 0.05. Conversely, no statistically significant differences were found in the levels of 15 REEs or ΣREEs in the blood samples between the REEs-exposed group and non-exposed group. Moreover, the concentrations of ΣREEs and 9 REEs in nail samples of the exposed group were significantly higher than those of the non-exposed group (P < 0.05), and the composition ratios of REEs in the nail samples closely resembled those found in individual airborne particles. Therefore, nail and urine samples were proposed to reflect long-term and short-term exposure to ionic rare earth respectively. Exposure biomarkers confirmed by external and internal exposure characteristics accurately provide the situation of human exposure to REEs environment, and have profound significance for monitoring and evaluating the level of REEs pollution in human body. It also provides a vital basis to find out the effect biomarkers, susceptible biomarkers and the health effects of rare earth environment for the future research.

Organophosphorus flame retardants and their metabolites in paired human blood and urine.

Organophosphorus flame retardants (OPFRs) have been shown to be carcinogenic, neurotoxic, and endocrine disruptive, so it is important to understand the levels of OPFRs in human body as well as the modes of external exposure. In this study, we investigated the levels of 13 OPFRs and 7 phosphodiester metabolites in paired human blood and urine, as well as the influencing factors (region, age and gender), and studied the relationship between OPFRs and oxidative stress by urinary metabolites. We found that the concentrations of triphenyl phosphate (TPhP) and tris-(2-ethylhexyl) phosphate (TEHP) in the blood of urban populations were higher than those of rural populations, and that younger populations suffered higher TPhP and 2-ethylhexyl diphenyl phosphate (EHDPP) exposures than older populations. In addition, we found that tris-(2-chloroethyl) phosphate (TCEP), tributyl phosphate (TnBP), TPhP and EHDPP exposure induced oxidative stress. The results of the internal load principal component analysis indicated that dust ingestion, skin exposure, respiration and dietary intake may be the most important sources of TCEP, tris(2-butoxyethyl) phosphate (TBOEP), tri(2-chloroisopropyl) phosphate (TCIPP) and TEHP, respectively, and dust ingestion and skin exposure may be the main sources of TPhP for humans.

Air kerma rate from radionuclides distributed in forest ecosystem.

This study evaluates the air kerma rate in radioactively contaminated forests. The air kerma rates created by plane sources of monoenergetic photons in the energy range 0.02-3 MeV located at different depths in soil up to 50 g cm-2 and at different heights in the forest medium from 0.05 to 50 m were calculated using numeric solution of the transport (Boltzmann) equation. To simplify the practical use of the results obtained by solving the Boltzmann equation, the study additionally includes approximation formulae for calculating air kerma rate separately from contaminated soil, crowns and trunks of trees in a forest ecosystem for 20 radionuclides - fission products that significantly contribute to the external dose. Biomaterial of trunks and crowns was modeled as uniformly distributed in corresponding layers and homogeneously mixed with air. Different distributions of radionuclides in soil were considered including plane source located at different depths, exponential and uniform distribution. Based on the results, the effect of forest biomass presence as an absorbing and scattering medium on the air kerma rate at 1 m above soil was evaluated. The estimated relative difference in air kerma rate at 1 m above soil in the forest medium and in free air for monoenergetic photon sources with energies 0.1 MeV, 0.66 MeV and 3 MeV did not correlate significantly with the energy of photons. Its maximum value in forest medium with biomass density of 5 kg m-3 was 15-20% for the source at soil depth ∼0.3 g cm-2, decreasing to less than 5% when it is at soil depth greater than 7 g cm-2. An example calculation of the air kerma rate dynamics is presented for the initial period after radioactive fallout considering weathering processes (rainfall and wind action) that contribute to the transfer of activity from the canopies to the forest floor. The differences in air kerma rate values, as an integral characteristic of the gamma radiation field from a radioactive cloud in the forest and in the open area, were evaluated.

Infantile Internal and External Exposure to Neonicotinoid Insecticides: A Comparison of Levels across Various Sources.

Little is known about exposure of infants to neonicotinoid insecticides (NEOs). In this study, concentrations of six parent NEOs (p-NEOs) and N-desmethyl-acetamiprid (N-dm-ACE) were measured in urine and whole blood samples from infants, in addition to breast milk, infant formula, and tap water collected in South China. The p-NEO with the highest median concentration in urine (0.25 ng/mL) and blood (1.30) samples was dinotefuran (DIN), while imidacloprid (IMI) was abundant in breast milk (median: 0.27 ng/mL), infant formula (0.22), and tap water (0.028). The older infants (181-360 days) might face higher NEO and N-dm-ACE exposure than younger infants (0-180 days). Blood samples contained a significantly (p < 0.01) higher median concentration of ∑6p-NEOs (2.03 ng/mL) than that of urine samples (0.41), similar to acetamiprid (ACE), IMI, thiacloprid (THD), DIN, and N-dm-ACE, suggesting that NEOs readily partition into blood. Furthermore, breast-fed infants tend to have higher exposure levels than formula-fed infants. Infant formula prepared with tap water augmented the daily intake of ∑NEOs. The external sources contributed 80% of the total dose to IMI and clothianidin (CLO) exposure, while other unknown sources contributed to ACE, THD, and DIN exposure in infants. To the best of our knowledge, this is the first study to assess levels and sources of infantile exposure to NEOs through internal and external exposure assessment.

External exposure assessment in the Fukushima accident area for governmental policy planning in Japan; Part 2. Matters to be attended for assessments of external exposure.

After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, individual exposure doses to residents have been assessed by many municipalities, governments and research institutes. Various methods including measurements with personal dosimeters and simulations have been used for this evaluation depending on purposes, but the information of assessments and methods has not been systematically organized. A comprehensive review of the knowledge and experiences of individual exposure doses assessments accumulated so far and understanding the characteristics of the assessment methods will be very useful for radiation protection and risk communication, following to governmental policy planning. We reviewed the efforts made by the Japanese government and research institutes to assess radiation doses to residents after the FDNPS accident in Part 1. On the other hand, each method of assessing individual exposure doses includes uncertainties and points to be considered for the appropriate assessment. These knowledge and experiences are important for the assessment implementation and applying the assessment results to the governmental policy planning, and are summarized in Part 2 of this article.

Analysis of individual dose monitoring results for medical radiation workers from occupational external exposure in Chongqing City, 2016-2020 / 中国热带医学

@#Abstract: Objective　To retrospectively analyze the individual dose monitoring of radiation workers in Chongqing City from 2016 to 2020, so as to provide scientific reference for occupational health monitoring and radiation protection. Methods　Radiation workers who performed individual dose monitoring in Chongqing Center for Disease Control and Prevention from 2016 to 2020 were selected as the research objects, and the monitoring data were collected and analyzed. Results　A total of 40 926 individuals were included in this study, with a total of 135 622 person-years. The average annual individual effective dose of radiation workers over the five-year period was 0.56 mSv. NR1 and NR5, the ratio of the number of works receiving annual individual does exceeding 1 and 5 mSv to the to the total monitor workers were 13.019% and 0.335%. The annual effective dose per capita in Chongqing City showed a trend of first decreasing, then increasing and then decreasing again over the study period, with significant differences between different years (F=971.754, P<0.001). Although there were some differences in the variation trend of annual effective dose among different occupational categories, the overall trend was decreasing year by year. The average annual effective dose of nuclear medicine and interventional radiology was relatively high, and the difference was not statistically significant (P>0.05). The average annual effective dose of industrial flaw detection and accelerator operator in industrial application was relatively higher, and the difference was not statistically significant (P>0.05). There were statistically significant differences in the per capita effective doses of different occupational categories of medical application in different years (F=8.892-682.852, P<0.001). Among them, the per capita annual effective doses of five occupational categories of medical application were the highest in 2016, and the per capita annual effective doses of interventional radiology were the highest in 2018 and 2019. Conclusions　The per capita annual effective dose of radiation staff in Chongqing has decreased year by year from 2016 to 2020, and remained at a relatively low level that meets national standards. The monitoring results suggest that the radiation staff of nuclear medicine, interventional radiology, industrial non-destructive testing and accelerator operator should give special attention to protect their occupational health and safety.

External exposure assessment in the Fukushima accident area for governmental policy planning in Japan: part 1. Methodologies for personal dosimetry applied after the accident.

The evacuation order areas established due to the accident at the Tokyo Electric Power Company Holdings' (TEPCO) Fukushima Daiichi Nuclear Power Plant (FDNPP) have been reorganized according to the decrease in ambient dose rates and the decontamination progress. The Japanese government decided to decontaminate the difficult-to-return areas and lift the evacuation order by 2030. This radiation protection strategy can be optimized by examining emergency exposure situations to date and the existing exposure after the accident. This article reviews the methods that can determine the individual radiation doses of residents who should return to their homes when the evacuation order is lifted in the specific reconstruction reproduction base area and the difficult-to-return areas outside this base area and summarizes the points to be considered when implementing these methods. In Part 1 of this article, we review the efforts made by the Japanese government and research institutes to assess radiation doses to residents after the FDNPP accident.

A new software for rapid estimation of external dose to the public due to environmental radioactive contamination / 中华放射医学与防护杂志

Objective:To develop a software for rapid estimation of external dose to the public due to environmental radioactive contamination.Methods:Based on the data provided by the International Commission on Radiological Protection (ICRP), a database of the conversion coefficients of external dose rates for the public (adult and children of different age groups) under different environmental exposure scenarios was created. The programs of data search and calculation were written using Python language, and the software interface was designed using PyQt toolkit. To test the calculation results, the differences in external doses to different age groups of the public caused by most likely produced radionuclides under three environmental exposure scenarios were calculated, and their rationalities were analyzed.Results:The software can immediately complete the estimation of the organ equivalent doses and the effective dose due to the external exposure form environmental contamination by using a personal computer with a Windows system, and its results are reasonable. The test results showed that the younger the public members, the larger the organ dose and effective dose. For soil surface and water contaminated with 90Sr with the same activity concentration reaching radioactive equilibrium, the effective dose to infants was about 6.08 times and 2.51 times those to adults, respectively. Conclusions:The software developed in this study has the advantages of simple operation and fast calculation, and is suitable for rapid estimation of external dose to the public members of different age groups in emergency situations such as nuclear accidents.

Pay attention to health hazards of diesel exhaust exposure, and strengthen occupational protection / 环境与职业医学

The air pollution related health hazards have been a major public health issue for a long time. As an important source of air pollution, diesel exhaust (DE) exposure associates with serious adverse health outcomes. Apart from the exposure in general population, extensive occupational DE exposure populations are reported in many industries, such as transportation, mining, shipping, and construction. Therefore, the studies for internal exposure levels, biomarkers, and toxic mechanisms of DE in occupational population are critical for protecting human from DE-posed health hazards. This special column published some novel findings involving DE exposure (internal & external exposure level), multiple biological effects, toxicity mechanisms, key molecular events, and crucial biomarkers. These studies will provide scientific data for controlling DE associated occupational health hazards, formulating effective DE pollution control strategies, and provide a new scientific perspective and evidence for health risk assessment and prevention.

Dietary Intake Contributed the Most to Chlorinated Paraffin Body Burden in a Norwegian Cohort.

Determining the major human exposure pathways is a prerequisite for the development of effective management strategies for environmental pollutants such as chlorinated paraffins (CPs). As a first step, the internal and external exposure to CPs were quantified for a well-defined human cohort. CPs in participants' plasma and diet samples were analyzed in the present study, and previous results on paired air, dust, and hand wipe samples were used for the total exposure assessment. Both one compartment pharmacokinetic modeling and forensic fingerprinting indicate that dietary intake contributed the most to body burden of CPs in this cohort, contributing a median of 60-88% of the total daily intakes. The contribution from dust ingestion and dermal exposure was greater for the intake of long-chain CPs (LCCPs) than short-chain CPs (SCCPs), while the contribution from inhalation was greater for the intake of SCCPs than medium-chain CPs (MCCPs) and LCCPs. Significantly higher concentrations of SCCPs and MCCPs were observed in diets containing butter and eggs, respectively (p < 0.05). Additionally, other exposure sources were correlated to plasma levels of CPs, including residence construction parameters such as the construction year (p < 0.05). This human exposure to CPs is not a local case. From a global perspective, there are major knowledge gaps in biomonitoring and exposure data for CPs from regions other than China and European countries.

Decreased hearing levels at frequencies for understanding speech in tannery workers exposed to a high level of trivalent chromium in Bangladesh.

Hexavalent chromium [Cr(VI)], which has a strong corrosive effect, has been reported to cause perforation of the eardrum. Trivalent chromium [Cr(III)] also has a weak corrosive effect. However, there has been no study on the effects of exposure to Cr, either Cr(VI) or Cr(III), on hearing levels in animals or humans. In this study, the effect of Cr(III) exposure on hearing levels was determined in a human study. Then the reproducibility of the results obtained in the human study and the etiology were investigated in an animal study. The mean levels of total chromium (t-Cr) in hair and toenails from 100 Bangladeshi tannery workers were >20-fold and >360-fold higher, respectively, than those in hair and toenails from 49 Bangladeshi non-tannery workers (office workers). Multivariate analysis revealed decreases of hearing levels (DHLs) at 1 k and 4 k Hz, frequencies that are crucial for understanding language, but not at 8 k and 12 k Hz, in the tannery workers. Since >99.99% of t-Cr in the wastewater that the workers were in direct contact with in the tanneries was Cr(III), the epidemiological results suggest Cr(III)-mediated DHLs in the tannery workers. The results of animal experiments in this study further showed that treatment with eardrops but not intraperitoneal injection with the same amount of Cr(III) that tannery workers might be exposed to resulted in DHL with a damaged eardrum in mice. Previous studies suggested that Cr(III) can directly reach the eardrums of tannery workers via droplets in the air. Cr(III) could also reach the eardrum via picking an ear canal with a finger contaminated with tannery wastewater including Cr(III). Taken together, the results of both human and animal studies suggest the risk of DHLs caused by damage of the eardrum through external exposure to Cr(III) via the ear canal.

Exposure of preschool-aged children to highly-concerned bisphenol analogues in Nanjing, East China.

Bisphenol analogues (BPs) have already attracted wide concern owing to the environmental and health risks they pose. The exposure pathways and health risk of preschool-aged children to BPs, however, are still poorly understood. In this study, we choose population survey with 184 preschool-age children from a suburb of Nanjing, eastern China, further reveal the internal and external exposures concentrations, distribution profiles, potential sources and eventually assess health risk of preschool-age children to eight kinds of BPs. The results verify that the 95th percentile (P95) concentrations of Æ©8BPs ranged from 0.27 to 41.6 ng/mL, with a median concentration of 7.83 ng/mL in the urine samples. BPA, and BPF were the predominant BPs in urine, accounting for 67.3%, and 18.0% of Æ©8BPs. The urine-based estimated daily intake (EDI) of Æ©8BPs was 187 ng/kg body weight/day. Similarly, BPA, and BPF were the main BPs in the environmental exposure sources, accounting for 80.8%, and 11.7% of the total BPs. Moreover, the total external exposure dose of Æ©8BPs via the environmental sources was 68.1 ng/kg body weight/day, including BPA (56 ng/kg body weight/day), BPF (7.68 ng/kg body weight/day) and BPB (2.62 ng/kg body weight/day). The oral intake of drinking water and food (vegetables and rice) was the main exposure pathways of BPs in preschool-age children. Furthermore, the hazard quotient (HQ) of BPs have been evaluated and the results show no occurrence of high risk. Additionally, the urine-based EDI was significantly higher than the total external exposure dose, suggesting the existence of other pathways of BP exposure to be further explored. To the best of our knowledge, this is the first study to conduct both an internal and external exposure assessment of BPs.

Environmental monitoring and external exposure to natural radiation in Canada.

External sources of radiation originate from cosmic rays and natural radioactive elements, principally 40K and decay products in the uranium and thorium decay series occurring in the ground. People are exposed to terrestrial radiation and cosmic rays everywhere and at all times. To assess Canadians' external exposure to natural radiation, five years (2016-2020) of real-time environment monitoring data recorded by Health Canada's Fixed Point Surveillance (FPS) network were analysed for 36 monitoring stations across Canada. Absorbed dose rates in air from terrestrial radiation vary geographically and seasonally. Absorbed dose rates due to cosmic rays depend strongly on the elevation and vary with solar activities. The population-weighted annual outdoor ambient dose equivalent rates are 20 nSv/h for terrestrial radiation and 52 nSv/h for cosmic rays. Considering that, on average, Canadians spend 89% of their time indoors and 11% of the time outdoors, the population-weighted annual effective doses were calculated as 443 µSv (54 µSv outdoors and 389 µSv indoors), with 20.6% (91 µSv) from terrestrial radiation and 79.4% (352 µSv) from cosmic rays.

Estimation of population exposure to terrestrial gamma rays in Canada.

Based on ground gamma ray spectrometry surveys conducted from 2007 to 2010 in populated areas across Canada (i.e. in southern Canada, excluding the northern territories), and with consideration of the exposure outdoors and indoors in various types of buildings as well as exposure to radionuclides in building materials (assuming most building materials are of local origin), the population-weighted annual effective dose from exposure to terrestrial gamma rays was estimated to be 167 ± 43µSv. Under Canadian-specific average occupancy times, indoor exposures at home contribute 69% of the total annual effective dose, followed by 19% from indoor exposures other than at home, 6.2% from outdoor exposures and 5.8% from exposures inside vehicles. This assessment with measurements in a total of 1057 sites in populated areas across Canada is in general agreement with earlier assessments based on airborne gamma surveys mostly over unpopulated areas of Canada and truck-borne radiometric surveys along paved urban roads in four cities.

External Exposure to BTEX, Internal Biomarker Response, and Health Risk Assessment of Nonoccupational Populations near a Coking Plant in Southwest China.

Benzene, toluene, ethylbenzene and xylene isomers (BTEX) have raised increasing concern due to their adverse effects on human health. In this study, a coking factory and four communities nearby were selected as the research area. Atmospheric BTEX samples were collected and determined by a preconcentrator GC-MS method. Four biomarkers in the morning urine samples of 174 participants from the communities were measured by LC-MS. The health risks of BTEX exposure via inhalation were estimated. This study aimed to investigate the influence of external BTEX exposure on the internal biomarker levels and quantitatively evaluate the health risk of populations near the coking industry. The results showed that the average total BTEX concentration in residential area was 7.17 ± 7.24 µg m-3. Trans,trans-muconic acid (T,T-MA) was the urinary biomarker with the greatest average level (127 ± 285 µg g-1 crt). Similar spatial trends can be observed between atmospheric benzene concentration and internal biomarker levels. The mean values of the LCR for male and female residents were 2.15 × 10-5 and 2.05 × 10-5, respectively. The results of the risk assessment indicated that special attention was required for the non-occupational residents around the area.

Research progress of the impact of the Fukushima Daiichi nuclear accident on childhood thyroid cancer / 中华放射医学与防护杂志

In March 2011, a nuclear accident happened and released a large amount of radionuclides into the environment in Fukushima, Japan. This review introduced the latest findings on the relationship between childhood thyroid cancer and radiation exposure after the accident in Fukushima. Many reports suggested that there was no accurate correlation between the incidence of childhood thyroid cancer and the local external dose due to the accident at the Fukushima Daiichi nuclear power, while the relationship between the two varied with method of dose calculation and statistics. Also there was no clear evidence that radiation exposure had a negative impact on children′s thyroid, and the increased incidence of thyroid cancer may be due to over-screening.

Monitoring on individual dose among radiation workers in medical institutions in Shanghai from 2015 to 2019 / 上海预防医学

ObjectiveTo determine the individual dose level and changing trend in the occupational external exposure of radiation workers in Shanghai， and provide scientific evidence for health risk assessment for radiation workers. MethodsIn the Occupational Health Management System for Radiation Workers of the National Health Commission-External Exposure Personal Monitoring and Management Subsystem， we retrieved the monitoring data of 38 077 external exposure individual dose of all medical radiation workers in Shanghai from 2015 to 2019. Using clustered sampling method， a total of 11 370 radiation workers in medical institutions （including tertiary， secondary， and primary hospitals） were selected in the study. Statistical analyses were conducted using SPSS 22.0. ResultsThe collective annual effective dose of 11 370 radiation workers was determined to be 4.340 person Sv， including 2.270 man·mSv in diagnostic radiology， 1.112 man·mSv in interventional radiology， and <0.5 man·mSv in other categories. The average annual effective dose was 0.382 mSv， which was 0.482 mSv in nuclear medicine， 0.431 mSv in radiotherapy， and <0.5 mSv in other categories. Moreover， the average annual effective dose of 6 workers （0.05%） was higher than 5 mSv， whereas that of 10 453 workers （92%） were less than 1 mSv； in addition， the annual dose of 911 workers （8.0%） was between 1‒5 mSv. All workers had average annual effctive dose lower than 20 mSv. The annual effective dose differed significantly by years （F=161.1， P<0.01）， by occupational groups （F=13.5， P<0.01）， and by hospital levels （F=264.5， P<0.01）. ConclusionThe average annual effective dose of radiation workers in medical institutions in Shanghai is lower than the national standard limit， suggesting proper and adequate radiation protection system and measures in medical institutions.

The Eco-Exposome Concept: Supporting an Integrated Assessment of Mixtures of Environmental Chemicals.

Organisms are exposed to ever-changing complex mixtures of chemicals over the course of their lifetime. The need to more comprehensively describe this exposure and relate it to adverse health effects has led to formulation of the exposome concept in human toxicology. Whether this concept has utility in the context of environmental hazard and risk assessment has not been discussed in detail. In this Critical Perspective, we propose-by analogy to the human exposome-to define the eco-exposome as the totality of the internal exposure (anthropogenic and natural chemicals, their biotransformation products or adducts, and endogenous signaling molecules that may be sensitive to an anthropogenic chemical exposure) over the lifetime of an ecologically relevant organism. We describe how targeted and nontargeted chemical analyses and bioassays can be employed to characterize this exposure and discuss how the adverse outcome pathway concept could be used to link this exposure to adverse effects. Available methods, their limitations, and/or requirement for improvements for practical application of the eco-exposome concept are discussed. Even though analysis of the eco-exposome can be resource-intensive and challenging, new approaches and technologies make this assessment increasingly feasible. Furthermore, an improved understanding of mechanistic relationships between external chemical exposure(s), internal chemical exposure(s), and biological effects could result in the development of proxies, that is, relatively simple chemical and biological measurements that could be used to complement internal exposure assessment or infer the internal exposure when it is difficult to measure. Environ Toxicol Chem 2022;41:30-45. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.