Assessing 134Cs & 137Cs levels in abiotic and biotic samples in British Columbia following the Fukushima Nuclear Accident
Presentation Abstract
The Fukushima nuclear power plant accident on March 11, 2011 raised global concerns due to the uncontrolled release of radioisotopes into the atmosphere and Pacific Ocean. With the aim to investigate potential Fukushima-associated radioactive contamination in British Columbia, detailed analysis of 134Cs and 137Cs activity levels in abiotic (soil and clay) and biotic (wild Pacific salmon including, Chinook, Oncorhynchus tshawytscha; chum, O. keta; and sockeye, O. nerka, as well as roof plant-material) samples collected in British Columbia was performed using gamma-ray spectroscopy. The extended source shape of each sample was modeled using the GEANT4 software package, previously developed to model the Germanium Detector for Elemental Analysis and Radioactivity Studies (GEARS), in order to measure the larger environmental samples. 134Cs and 137Cs activity levels were compared relative to 40K, a (Naturally Occuring Radioactive Material (NORM), to examine the impact of anthropogenic radiation relative to existing natural background radiation. In abiotic samples, the maximum 134Cs and 137Cs activity concentrations measured were 1.33(17) and 155.6(19) Bq/kg respectively while in the salmon biotic samples, the maximum 137Cs activity concentrations measured was 2.8(4) Bq/kg. 134Cs was not detected in any of the salmon samples. In the single plant biotic sample, the activiy concentrations for 134Cs and 137Cs were measured to be 13.1(2) and 54.4(8) Bq/kg. The Minimum Detection Limit (MDL) was calculated for samples where neither 134Cs and 137Cs were detected to provide an upper limit for the amount of each radioisotope present. The maximum ratio of anthropogenic activity to naturally occurring activity in all of the samples measured was 0.0336(9) and 0.68(2) for 134Cs/40K and 137Cs/40K respectively, though the required ratios to give equal dose contributions from man-made and naturally occurring radioactivity would be 3.17 and 2.67. It was observed that in the samples where 134Cs was positively identified, 7Be was also detected suggesting the contribution of 134Cs into these samples may have been through the atmospheric deposition rather then through ocean currents. For all samples, the measured activity concentration of 134Cs and 137Cs were below 1000 Bq/kg, the 134Cs and 137Cs action level for commercial food and beverages established by the Canadian Guidelines for the Restriction of Radioactively Contaminated Food and Water Following a Nuclear Emergency
Session Title
Fossil Fuel Export Panel
Conference Track
Fate and Effects of Pollutants
Conference Name
Salish Sea Ecosystem Conference (2016 : Vancouver, B.C.)
Document Type
Event
Location
2016SSEC
Type of Presentation
Poster
Genre/Form
presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Fukushima Nuclear Disaster, Japan, 2011; Radioactivity--Measurement; Fishes—Radioactive contamination--Salish Sea (B.C. and Wash.); Plants—Radioactive contamination--Salish Sea (B.C. and Wash.)
Geographic Coverage
Salish Sea (B.C. and Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
Assessing 134Cs & 137Cs levels in abiotic and biotic samples in British Columbia following the Fukushima Nuclear Accident
2016SSEC
The Fukushima nuclear power plant accident on March 11, 2011 raised global concerns due to the uncontrolled release of radioisotopes into the atmosphere and Pacific Ocean. With the aim to investigate potential Fukushima-associated radioactive contamination in British Columbia, detailed analysis of 134Cs and 137Cs activity levels in abiotic (soil and clay) and biotic (wild Pacific salmon including, Chinook, Oncorhynchus tshawytscha; chum, O. keta; and sockeye, O. nerka, as well as roof plant-material) samples collected in British Columbia was performed using gamma-ray spectroscopy. The extended source shape of each sample was modeled using the GEANT4 software package, previously developed to model the Germanium Detector for Elemental Analysis and Radioactivity Studies (GEARS), in order to measure the larger environmental samples. 134Cs and 137Cs activity levels were compared relative to 40K, a (Naturally Occuring Radioactive Material (NORM), to examine the impact of anthropogenic radiation relative to existing natural background radiation. In abiotic samples, the maximum 134Cs and 137Cs activity concentrations measured were 1.33(17) and 155.6(19) Bq/kg respectively while in the salmon biotic samples, the maximum 137Cs activity concentrations measured was 2.8(4) Bq/kg. 134Cs was not detected in any of the salmon samples. In the single plant biotic sample, the activiy concentrations for 134Cs and 137Cs were measured to be 13.1(2) and 54.4(8) Bq/kg. The Minimum Detection Limit (MDL) was calculated for samples where neither 134Cs and 137Cs were detected to provide an upper limit for the amount of each radioisotope present. The maximum ratio of anthropogenic activity to naturally occurring activity in all of the samples measured was 0.0336(9) and 0.68(2) for 134Cs/40K and 137Cs/40K respectively, though the required ratios to give equal dose contributions from man-made and naturally occurring radioactivity would be 3.17 and 2.67. It was observed that in the samples where 134Cs was positively identified, 7Be was also detected suggesting the contribution of 134Cs into these samples may have been through the atmospheric deposition rather then through ocean currents. For all samples, the measured activity concentration of 134Cs and 137Cs were below 1000 Bq/kg, the 134Cs and 137Cs action level for commercial food and beverages established by the Canadian Guidelines for the Restriction of Radioactively Contaminated Food and Water Following a Nuclear Emergency
