Radiocesium concentrations and GPS-coupled dosimetry in Fukushima snakes

Hannah C Gerke; Thomas G Hinton; Tsugiko Takase; Donovan Anderson; Kenji Nanba; James C Beasley

doi:10.1016/j.scitotenv.2020.139389

Radiocesium concentrations and GPS-coupled dosimetry in Fukushima snakes

Sci Total Environ. 2020 Sep 10:734:139389. doi: 10.1016/j.scitotenv.2020.139389. Epub 2020 May 14.

Authors

Hannah C Gerke¹, Thomas G Hinton², Tsugiko Takase³, Donovan Anderson³, Kenji Nanba³, James C Beasley⁴

Affiliations

¹ University of Georgia, Savannah River Ecology Laboratory, Aiken, SC 29802, USA; University of Georgia, Warnell School of Forestry and Natural Resources, Athens, GA 30602, USA. Electronic address: hgerke.23@gmail.com.
² Institute of Environmental Radioactivity, Fukushima University, 960-1248, Kanayagawa, Fukushima Prefecture, Fukushima, Japan; CERAD CoE, Norwegian University of Life Sciences, Faculty for Environmental Sciences and Nature Research Management, Aas, Norway.
³ Institute of Environmental Radioactivity, Fukushima University, 960-1248, Kanayagawa, Fukushima Prefecture, Fukushima, Japan.
⁴ University of Georgia, Savannah River Ecology Laboratory, Aiken, SC 29802, USA; University of Georgia, Warnell School of Forestry and Natural Resources, Athens, GA 30602, USA.

PMID: 32464388
DOI: 10.1016/j.scitotenv.2020.139389

Abstract

One of the largest releases of radioactive contamination in history occurred at Japan's Fukushima Daiichi Nuclear Power Plant (FDNPP). Although the accident happened in 2011, questions still persist regarding its ecological impacts. For example, relatively little is known about radiocesium accumulation in snakes, despite their high trophic status, limited home range sizes, and close association with soil where many radionuclides accumulate. This study presents one of the most comprehensive radioecological studies of snakes published to date using a combination of whole-body radiocesium analyses, GPS transmitters, and optically stimulated luminescence (OSL) dosimeters. The objectives were to: 1) quantify whole-body radiocesium activity concentrations and internal dose rates among several common species of snakes within and around the Fukushima Exclusion Zone (FEZ), 2) determine effects of species, sex, and body size on radiocesium activity concentrations, 3) measure external dose rates using GPS-coupled dosimeters deployed on free-ranging snakes, 4) compare field-derived empirical dose rates to those generated by computer simulation software (i.e., the ERICA tool), and 5) determine if incorporating snake behavior into computer models improve simulated estimates of external dose. Whole-body radiocesium levels for snakes were highly variable among individuals (16 to 25,000 Bq/kg, FW), but were influenced more by levels of local contamination than species, sex, or size. Doses recorded by OSL dosimeters on snakes, as well as modeling in ERICA, suggest that individual movements and behavior have a substantial influence on dose rates to snakes. However, dose estimates produced with ERICA were comparable to dose received by tracked snakes. The average external plus internal dose rate for snakes captured in the FEZ was 3.6-3.9 μGy/h, with external dose contributing 80% to the total. Further research regarding reptile-specific benchmark dose rates would improve risk assessment for reptiles in radiologically contaminated areas.

Keywords: Behavior; Concentration ratio; Fukushima; Radiation dose; Radiocesium; Reptile.

MeSH terms

Animals
Cesium Radioisotopes
Computer Simulation
Fukushima Nuclear Accident*
Japan
Radiation Monitoring*
Snakes
Soil Pollutants, Radioactive
Water Pollutants, Radioactive

Substances

Cesium Radioisotopes
Soil Pollutants, Radioactive
Water Pollutants, Radioactive