Representative Public Health Surveys Pose Several Challenges: Lessons Learned Across 9 Communities During the COVID-19 Pandemic.

Community surveillance surveys offer an opportunity to obtain important and timely public health information that may help local municipalities guide their response to public health threats. The objective of this paper is to present approaches, challenges, and solutions from SARS-CoV-2 surveillance surveys conducted in different settings by 2 research teams. For rapid assessment of a representative sample, a 2-stage cluster sampling design was developed by an interdisciplinary team of researchers at Oregon State University between April 2020 and June 2021 across 6 Oregon communities. In 2022, these methods were adapted for New York communities by a team of veterinary, medical, and public health practitioners. Partnerships were established with local medical facilities, health departments, COVID-19 testing sites, and health and public safety staff. Field staff were trained using online modules, field manuals describing survey methods and safety protocols, and in-person meetings with hands-on practice. Private and secure data integration systems and public awareness campaigns were implemented. Pilot surveys and field previews revealed challenges in survey processes that could be addressed before surveys proceeded. Strong leadership, robust trainings, and university-community partnerships proved critical to successful outcomes. Cultivating mutual trust and cooperation among stakeholders is essential to prepare for the next pandemic.

Evaluation of a Wastewater-Based Epidemiological Approach to Estimate the Prevalence of SARS-CoV-2 Infections and the Detection of Viral Variants in Disparate Oregon Communities at City and Neighborhood Scales.

BACKGROUND: Positive correlations have been reported between wastewater SARS-CoV-2 concentrations and a community's burden of infection, disease or both. However, previous studies mostly compared wastewater to clinical case counts or nonrepresentative convenience samples, limiting their quantitative potential. OBJECTIVES: This study examined whether wastewater SARS-CoV-2 concentrations could provide better estimations for SARS-CoV-2 community prevalence than reported cases of COVID-19. In addition, this study tested whether wastewater-based epidemiology methods could identify neighborhood-level COVID-19 hotspots and SARS-CoV-2 variants. METHODS: Community SARS-CoV-2 prevalence was estimated from eight randomized door-to-door nasal swab sampling events in six Oregon communities of disparate size, location, and demography over a 10-month period. Simultaneously, wastewater SARS-CoV-2 concentrations were quantified at each community's wastewater treatment plant and from 22 Newport, Oregon, neighborhoods. SARS-CoV-2 RNA was sequenced from all positive wastewater and nasal swab samples. Clinically reported case counts were obtained from the Oregon Health Authority. RESULTS: Estimated community SARS-CoV-2 prevalence ranged from 8 to 1,687/10,000 persons. Community wastewater SARS-CoV-2 concentrations ranged from 2.9 to 5.1 log10 gene copies per liter. Wastewater SARS-CoV-2 concentrations were more highly correlated (Pearson's r=0.96; R2=0.91) with community prevalence than were clinically reported cases of COVID-19 (Pearson's r=0.85; R2=0.73). Monte Carlo simulations indicated that wastewater SARS-CoV-2 concentrations were significantly better than clinically reported cases at estimating prevalence (p<0.05). In addition, wastewater analyses determined neighborhood-level COVID-19 hot spots and identified SARS-CoV-2 variants (B.1 and B.1.399) at the neighborhood and city scales. DISCUSSION: The greater reliability of wastewater SARS-CoV-2 concentrations over clinically reported case counts was likely due to systematic biases that affect reported case counts, including variations in access to testing and underreporting of asymptomatic cases. With these advantages, combined with scalability and low costs, wastewater-based epidemiology can be a key component in public health surveillance of COVID-19 and other communicable infections. https://doi.org/10.1289/EHP10289.

From tangled banks to toxic bunnies; a reflection on the issues involved in developing an ecosystem approach for environmental radiation protection.

The objective of this paper is to present the results of discussions at a workshop held as part of the International Congress of Radiation Research (Environmental Health stream) in Manchester UK, 2019. The main objective of the workshop was to provide a platform for radioecologists to engage with radiobiologists to address major questions around developing an Ecosystem approach in radioecology and radiation protection of the environment. The aim was to establish a critical framework to guide research that would permit integration of a pan-ecosystem approach into radiation protection guidelines and regulation for the environment. The conclusions were that the interaction between radioecologists and radiobiologists is useful in particular in addressing field versus laboratory issues where there are issues and challenges in designing good field experiments and a need to cross validate field data against laboratory data and vice versa. Other main conclusions were that there is a need to appreciate wider issues in ecology to design good approaches for an ecosystems approach in radioecology and that with the capture of 'Big Data', novel tools such as machine learning can now be applied to help with the complex issues involved in developing an ecosystem approach.

Development of a coupled simulation toolkit for computational radiation biology based on Geant4 and CompuCell3D.

Understanding and designing clinical radiation therapy is one of the most important areas of state-of-the-art oncological treatment regimens. Decades of research have gone into developing sophisticated treatment devices and optimization protocols for schedules and dosages. In this paper, we presented a comprehensive computational platform that facilitates building of the sophisticated multi-cell-based model of how radiation affects the biology of living tissue. We designed and implemented a coupled simulation method, including a radiation transport model, and a cell biology model, to simulate the tumor response after irradiation. The radiation transport simulation was implemented through Geant4 which is an open-source Monte Carlo simulation platform that provides many flexibilities for users, as well as low energy DNA damage simulation physics, Geant4-DNA. The cell biology simulation was implemented using CompuCell3D (CC3D) which is a cell biology simulation platform. In order to couple Geant4 solver with CC3D, we developed a 'bridging' module, RADCELL, that extracts tumor cellular geometry of the CC3D simulation (including specification of the individual cells) and ported it to the Geant4 for radiation transport simulation. The cell dose and cell DNA damage distribution in multicellular system were obtained using Geant4. The tumor response was simulated using cell-based tissue models based on CC3D, and the cell dose and cell DNA damage information were fed back through RADCELL to CC3D for updating the cell properties. By merging two powerful and widely used modeling platforms, CC3D and Geant4, we delivered a novel tool that can give us the ability to simulate the dynamics of biological tissue in the presence of ionizing radiation, which provides a framework for quantifying the biological consequences of radiation therapy. In this introductory methods paper, we described our modeling platform in detail and showed how it can be applied to study the application of radiotherapy to a vascularized tumor.

Development of computational model for cell dose and DNA damage quantification of multicellular system.

Purpose: The aim of this study is to build a computational model to investigate the cell dose and cell DNA damage distribution of a multicellular tissue system under the irradiation.Materials and methods: In this work, we developed a computational model for quantifying cell dose and double strand break (DSB) number in a multicellular system by simulating the radiation transport in 2D and 3D cell culture. The model was based on an open-source radiation transport package, Geant4 with Geant4-DNA physics. First, the computational multicellular system was created using a developed program, CelllMaker. Second, the radiation transport simulation for cells was conducted using Geant4 package with the Geant4-DNA physics to obtain the cellular dose and cellular DSB yield.Results: Using the method described in this work, it is possible to obtain the cellular dose and DNA damage simultaneously. The developed model provides a solution for quantifying the cellular dose and cellular DNA damage which are not easily determined in a radiobiological experiment.Conclusions: With limited validation data for the model, this preliminary study provides a roadmap for building a comprehensive toolkit for simulating cellular dose and DNA damage of multicellular tissue systems.

Education vs. Training: Does it Matter?

The National Council on Radiation Protection and Measurements' (NCRP) "Where are the Radiation Professionals?" initiative brought renewed attention to the declining numbers of individuals in radiation protection fields. This paper is an expanded version of the oral presentation by the author at the 2016 NCRP Annual Meeting. Health physics (HP) as a discipline and vocation is at a critical juncture. Perhaps less well recognized is the extreme peril facing academic HP programs. Higher education today is vastly different from what it was even 20 y ago. Every academic program must now make a budget case to justify its existence. Consequently, HP programs, which are by anyone's measure minuscule, are in very real danger of closing. Given that the country will continue to need radiation protection expertise, we must take immediate steps to reinvigorate the profession and preserve academic programs. We simply cannot train or short-course our way out of this problem. Under routine conditions, individuals trained in basic HP can be expected to safely manage daily operations. But life is full of the unexpected. When the unexpected event involves radiation, we need someone well-versed in radiological fundamentals to understand, assess and safely deal with the problem. A three-pronged approach to bolster academic programs was offered: (1) increase academic cooperation and provide an infusion of cash, (2) more formally recognize the discipline of HP and increase respect for its role in safety, and (3) regulate who can be designated as a health physicist while increasing retention of individuals within the discipline.

Organ Dose-Rate Calculations for Small Mammals at Maralinga, the Nevada Test Site, Hanford and Fukushima: A Comparison of Ellipsoidal and Voxelized Dosimetric Methodologies.

Radiological dosimetry for nonhuman biota typically relies on calculations that utilize the Monte Carlo simulations of simple, ellipsoidal geometries with internal radioactivity distributed homogeneously throughout. In this manner it is quick and easy to estimate whole-body dose rates to biota. Voxel models are detailed anatomical phantoms that were first used for calculating radiation dose to humans, which are now being extended to nonhuman biota dose calculations. However, if simple ellipsoidal models provide conservative dose-rate estimates, then the additional labor involved in creating voxel models may be unnecessary for most scenarios. Here we show that the ellipsoidal method provides conservative estimates of organ dose rates to small mammals. Organ dose rates were calculated for environmental source terms from Maralinga, the Nevada Test Site, Hanford and Fukushima using both the ellipsoidal and voxel techniques, and in all cases the ellipsoidal method yielded more conservative dose rates by factors of 1.2-1.4 for photons and 5.3 for beta particles. Dose rates for alpha-emitting radionuclides are identical for each method as full energy absorption in source tissue is assumed. The voxel procedure includes contributions to dose from organ-to-organ irradiation (shown here to comprise 2-50% of total dose from photons and 0-93% of total dose from beta particles) that is not specifically quantified in the ellipsoidal approach. Overall, the voxel models provide robust dosimetry for the nonhuman mammals considered in this study, and though the level of detail is likely extraneous to demonstrating regulatory compliance today, voxel models may nevertheless be advantageous in resolving ongoing questions regarding the effects of ionizing radiation on wildlife.

Trace levels of Fukushima disaster radionuclides in East Pacific albacore.

The Fukushima Daiichi power station released several radionuclides into the Pacific following the March 2011 earthquake and tsunami. A total of 26 Pacific albacore (Thunnus alalunga) caught off the Pacific Northwest U.S. coast between 2008 and 2012 were analyzed for (137)Cs and Fukushima-attributed (134)Cs. Both 2011 (2 of 2) and several 2012 (10 of 17) edible tissue samples exhibited increased activity concentrations of (137)Cs (234-824 mBq/kg of wet weight) and (134)Cs (18.2-356 mBq/kg of wet weight). The remaining 2012 samples and all pre-Fukushima (2008-2009) samples possessed lower (137)Cs activity concentrations (103-272 mBq/kg of wet weight) with no detectable (134)Cs activity. Age, as indicated by fork length, was a strong predictor for both the presence and concentration of (134)Cs (p < 0.001). Notably, many migration-aged fish did not exhibit any (134)Cs, suggesting that they had not recently migrated near Japan. None of the tested samples would represent a significant change in annual radiation dose if consumed by humans.

Site-specific reference person parameters and derived concentration standards for the Savannah River Site.

The U.S. Department of Energy Order 458.1 states that the compliance with the 1 mSv annual dose constraint to a member of the public may be demonstrated by calculating dose to the maximally exposed individual (MEI) or to a representative person. Historically, the MEI concept was used for dose compliance at the Savannah River Site (SRS) using adult dose coefficients and adult male usage parameters. For future compliance, SRS plans to use the representative person concept for dose estimates to members of the public. The representative person dose will be based on the reference person dose coefficients from the U.S. DOE Derived Concentration Technical Standard and on usage parameters specific to SRS for the reference and typical person. Usage parameters and dose coefficients were determined for inhalation, ingestion and external exposure pathways. The reference intake for air, water, meat, dairy, freshwater fish, saltwater invertebrates, produce (fruits and vegetables), and grains for the 95th percentile are 17.4 m d, 2.19 L d, 220.6 g d, 674 cm d, 66.4 g d, 23.0 g d, 633.4 g d (448.5 g dand 631.7 g d) and 251.3 g d, respectively. For the 50th percentile: 13.4 m d, 0.809 L d, 86.4 g d, 187 cm d, 8.97 g d, 3.04 g d, 169.5 g d (45.9 g d and 145.6 g d), 101.3 g d, respectively. These parameters for the representative person were used to calculate and tabulate SRS-specific derived concentration standards (DCSs) for the pathways not included in DOE-STD-1196-2011.

Estimating transfer parameters in the absence of data.

The calculation of transfer of radionuclides from the abiotic to the biotic environment is a well-established practice in radiological assessments. Concentration ratios provide simple means to estimate radionuclide activity in biota, from measured (or estimated) radionuclide concentrations in either a food source or an abiotic component such as soil or water. They are typically reported by element, and data compilations may include information such as soil type (e.g., sand, loam, clay) and species. The data may be for multiple species at a single location, single species at multiple locations, or represent compilations from multiple sources. Recently published guidance suggests that estimates are best made using data from the same ecosystem. This paper examines this recent guidance, in the context of using measured data from within a single ecosystem and comparing results to more generic values. Results suggest that generic values may be an adequate substitute for site-specific information. It illustrates how ionic potential may be used as an alternative to group chemical properties in estimating transfer factors. Lastly, limited evidence is found to support the concept of allometric scaling functions for elemental concentrations in plants.

Derivation of a screening methodology for evaluating radiation dose to aquatic and terrestrial biota.

The United States Department of Energy (DOE) currently has in place a radiation dose standard for the protection of aquatic animals, and is considering additional dose standards for terrestrial biota. These standards are: 10 mGy/d for aquatic animals, 10 mGy/d for terrestrial plants, and, 1 mGy/d for terrestrial animals. Guidance on suitable approaches to the implementation of these standards is needed. A screening methodology, developed through DOE's Biota Dose Assessment Committee (BDAC), serves as the principal element of DOE's graded approach for evaluating radiation doses to aquatic and terrestrial biota. Limiting concentrations of radionuclides in water, soil, and sediment were derived for 23 radionuclides. Four organism types (aquatic animals; riparian animals; terrestrial animals; and terrestrial plants) were selected as the basis for development of the screening method. Internal doses for each organism type were calculated as the product of contaminant concentration, bioaccumulation factor(s) and dose conversion factors. External doses were calculated based on the assumption of immersion of the organism in soil, sediment, or water. The assumptions and default parameters used provide for conservative screening values. The screening methodology within DOE's graded approach should prove useful in demonstrating compliance with biota dose limits and for conducting screening assessments of radioecological impact. It provides a needed evaluation tool that can be employed within a framework for protection of the environment.

A probabilistic approach to obtaining limiting estimates of radionuclide concentration in biota.

The US Department of Energy has developed a graded approach for evaluating radiation doses to biota. Limiting concentrations of radionuclides in water, soil, and sediment were derived for twenty-three radionuclides. Four organism types (aquatic animals, riparian animals, terrestrial animals, and terrestrial plants) were selected as the basis for method development. While environmental transfer data needed for deriving biota tissue concentrations are available for aquatic animals and terrestrial plants, less information is available for terrestrial and riparian organisms. Two methods were applied and examined for their ability to provide estimates of organism:soil or organism:water concentration factors in lieu of measured data. The kinetic/allometric approach combined with a parameter uncertainty analysis provides a needed method to estimate concentration factors across multiple species with limited input data.