WPM-C - Environmental Monitoring Centennial Ballroom 300C 14:30 - 16:45
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| Chair(s): David Goodman and Jonathan Napier
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WPM-C.1
14:30 Quantifying Preferential Tissue Accumulation and Antioxidant Stress Response of a Marine Mussel After Exposure to Radium Paint SD Donaher*, Clemson University
; RP Dunn, University of South Carolina; BA Powell, Clemson University; P Van den Hurk, Clemson University; NE Martinez, Clemson University
Abstract: Radium-226 is a long-lived radionuclide which was a major component of radioluminescent paint that had widespread naval applications in the early 20th century. This paint was used to mark doorways or thresholds on ships or buildings, in deck markers for ships and docks, and on the faces of gauges, dials, and other vehicle instrumentation. This has led to contemporary contamination of coastal sediments with radioactive objects or paints chips. Risk assessments on such discrete radioactive material (RAM) are challenging due to the large amount of uncertainty in the bioavailability and ultimate toxicity of radium paint to marine biota. Bivalves in general, and mussels in particular, have a long ecotoxicological history as monitors of aquatic and marine contaminants; therefore, we utilized Geukensia demissa, the Atlantic ribbed mussel, as a representative estuarine species. Mussels were exposed to various concentrations of aqueous radium-226 in a laboratory setting over a range of exposure times. We examined the preferential uptake of radium in the soft tissue of the mussels as well as the effect of radium exposure on tissue antioxidant capacity, production of a stress-related enzyme, and mussel feeding behavior. This research will support the development of a cost-effective biomonitoring protocol to identify high priority remediation sites for legacy coastal contamination of radium paint.
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WPM-C.2
14:45 Use of 14C-PFOA to study uptake and effects of PFOA in Brassica juncea BD Wattier*, Clemson University
; AK Gonzales, Clemson University; S Donaher, Clemson University; TA DeVol, Clemson University; NE Martinez, Clemson University
Abstract: Perfluorooctanoic acid (PFOA), a surfactant, is a member of the perfluoroalkyl acids (PFAAs) family and is a contaminant of emerging concern for human and environmental health. PFOA is a persistent organic pollutant but currently little is known about (1) the potential ecological and toxicological effects of PFOA and (2) how PFOA moves in the environment. This study employs a radiotracer (14C-PFOA) to study the uptake and effects of PFOA in hydroponically grown Brassica juncea, a representative crop species. Plants were exposed in quadruplicate over the course of seven days (with plants sampled on day 4 and day 7) to PFOA concentrations of 0, 1, 5, 10, and 15 mg/L. Several biological endpoints were observed including chlorophyll content, biomass, height, and leaf number. Uptake was quantified via liquid scintillation counting of samples from the nutrient solution, roots, stems, and leaves. Preliminary results suggest that there are no adverse biological effects seen from this range of PFOA exposure with bioconcentration factors in leaves and roots ranging from 0.55 - 4.16 mL/g and 1.73 - 23.54 mL/g, respectively. Preliminary results also suggest that the average bioaccumulation factor for the leaves and roots increases with time at low concentrations but decreases with time at high concentrations of PFOA.
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WPM-C.3
15:00 Distribution and Radiological Impact Assessment of Natural Radionuclides in Nevada National Security Site X Liu*, MSTS
; RW Warren, MSTS
Abstract: According to the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) publications, contributions of terrestrial gamma doses are mainly from the presence of 40K and of 238U and 232Th together with their progeny in various rocks and soils. A survey of soil distributions of radionuclides 40K, 238U, and 232Th was performed in Nevada National Security Site (NNSS) using in situ gamma spectroscopy analysis. The average activity concentrations of 40K, 238U, and 232Th were 867 ± 38 Bq kg-1 (range from 150 to 1297 Bq kg-1), 50 ± 6 (range from 29 to 74 Bq kg-1), and 56 ± 8 Bq kg-1 (range from 11 to 96 Bq kg-1) respectively. The terrestrial gamma dose rates around NNSS was estimated from 26 to 144 nSv h-1 with mean value of 93 ± 9 nSv h-1. The results are compared with available published data and with results from soil samples from the NNSS. The radiological effects of the main naturally occurring radionuclides in NNSS are discussed.
This work was done by Mission Support and Test Services, LLC, under Contract No. DE-NA0003624 with the U.S. Department of Energy. DOE/NV/03624--0992.
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WPM-C.4
15:15 Lightweight, Low-Power, High-Resolution, Pixelated CdZnTe Detectors For Drone-Based Measurements DI Goodman*, H3D, Inc.
; DP Barron, Formally H3D, Inc., now Titan Robotics; JT Sowers, Formally H3D, Inc., now Skydio; AM Thomason, H3D, Inc.
Abstract: Advances in system design have led to lightweight (600g), low-power (5W), high-resolution (<1.0% energy resolution), pixelated CdZnTe detectors with ~20 cm3 active volume. These low-mass, pixelated CdZnTe systems represent the state-of-the-art in high-resolution, room-temperature gamma-ray detector instrumentation of drones. Practical engineering solutions to drone-based measurements problems, such as mitigating microphonics and thermal management, are discussed. Measured CdZnTe detector energy resolution and efficiency trends are compared against common drone-based instruments using NaI and LaBr3 detectors. CdZnTe detector capabilities are explored using real-world Technologically Enhanced Radioactive Material (TNORM) datasets collected via DJI drone at an abandoned natural gas site in northern Michigan. CdZnTe-generated site surveys are benchmarked against traditional NaI-based data. Survey hotspots were further studied using coded aperture and Compton gamma-ray imaging. First-order estimates of hotspot activities are made using a point-kernel-based quantitative analysis code. Potential corrections for spatially variant source attenuation, using 226Ra photopeak ratios from high-resolution gamma-ray spectroscopy, is explored. Subsequent developments into low-mass, drone-based CZT detectors with integrated optical cameras are discussed.
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WPM-C.5
15:30 Environmental Measurement of Gamma and Cosmic Radiation Using a Sensitive Spectroscopic Radiation Pager MA Iwatschenko-Borho*, Thermo Fisher Scientific Messtechnik GmbH
Abstract: The main purpose of spectroscopic personal radiation detectors according to ANSI 42.48 is to “detect changes in the radiation level, notify the user of these changes, and provide a means to determine if the alarm was caused by a radionuclide of interest that may require further evaluation.” Since this homeland security standard requires a fast response for these changes relative to a normal background radiation level, the detector must be very sensitive to gamma radiation. And, due to the spectroscopic properties that are necessary for the required nuclide identification, an energy compensated dose rate measurement at very low radiation levels can be achieved that is far superior to the minimum requirements in the standard. However, the dose rate reading at background level of such device may differ significantly compared to a pressurized ionization chamber or an energy compensate Geiger Mueller counter. This presentation will outline the physical reasons for these differences and provide an overview about the low level dose rate and detection capabilities of a radiation pagers using a CsI(Tl)-crystal.
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WPM-C.6
15:45 Break
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WPM-C.7
16:15 Spatial Representation of Determined Transfer Factors JB Napier*, Pacific Northwest National Laboratory
Abstract: Transfer factors are a conversion of the complex processes involved in molecular movement from a source to a target into a simple constant. For radionuclide transfer factors, factors like rainfall, growing season, and characteristics among others can impact the amount incorporated into a receptor. This leads to different values appearing in literature; however, many people who use transfer factors only use a single data point for calculations. Which leads to the question, how is a transfer factor selected to represent a location? The International Union of Radioecology curates a database for the International Atomic Energy Agency and International Council on Radiological Protection to create a centralized reference source of transfer factors. However, one item missing in this database is the physical location of each transfer factor. This presentation will analyze and compare the published collection locations of transfer factors. Visualization methods will show spatial data that relates to soil type, plant hardiness zones, and other location related characteristics that could impact the determined value of a transfer factor.
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WPM-C.8
16:30 Determination of Gross Alpha and Gross Beta Activity in recently imported organic fertilizer samples, Sri Lanka TL Weerakkody*, Sri Lanka Atomic Energy Board
; PR Dabare, Sri Lanka Atomic Energy Board; CK Dissanayake, Sri Lanka Atomic Energy Board
Abstract: Analysis of gross alpha and beta emitters by using iSolo alpha beta counting system is an important method to assess radioactivity levels in various sample matrices due to its simplicity and low cost. Twelve imported organic fertilizer samples (5 solid samples and 7 liquid samples) were measured by iSolo alpha beta counter (Model: SOLO300G) with solid state silicon PIPS detectors by using EPA 900.0 method. Only one liquid sample recorded 2616 Bq/l of gross beta activity and the others are below the minimum detectable activity (MDA) of 0.41Bq/l. Gross Alpha activities are well below the MDA of 0.0488 Bq/l. All the measured solid fertilizer samples having gross alpha and beta activities, lower than the MDA except two samples. The recorded gross beta activities are 2850 Bq/kg and 2760 Bq/kg respectively and the gross alpha activities are well below the MDA. This study will be continued further for environmental protection purposes.
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