Analysis of 129I and 127I in soils of the Chernobyl Exclusion Zone, 29 years after the deposition of 129I

George Shaw*, Elizabeth Bailey, Neil Crout, Lorraine Field, Stewart Freeman, Sergey Gaschak, Xiaolin Hou, Maria Izquierdo, Claire Wells, Sheng Xu, Scott Young

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The Chernobyl Exclusion Zone (CEZ) represents a unique natural laboratory that received significant 129I contamination across a range of soils and land-use types in a short time period in 1986. Data are presented on 129I and 127I in soil samples collected from highly contaminated areas in the CEZ in 2015. The geometric mean (GM) total concentration of stable iodine (127I) was 6.7 × 10−7 g g−1 and the (GM) total concentration of 129I was 2.39 × 10−13 g g−1, equivalent to 1.56 mBq kg−1. GM total 127I concentration is below the European average soil concentration of 3.94 × 10−6 g g−1, while 129I is significantly higher than the pre-Chernobyl activity concentration for 129I of 0.094 mBq kg−1. Significant differences were found in the extractability of native, stable 127I and 129I almost 30 years after the introduction of 129I to the soils. Both 127I and 129I were predominantly associated with alkaline-extractable soil organic matter, established using a three-step sequential extraction procedure. Whereas 127I was significantly correlated with gross soil organic matter (measured by loss on ignition), however, 129I was not. The ratio of 129I/127I was significantly lower in extracts of soil organic matter than in more labile (soluble and adsorbed) fractions, indicating incomplete equilibration of 129I with native 127I in soil humic substances after 29 years residence time in the CEZ soils. The initial physico-chemical form of 129I in the CEZ soils is unknown, but the widespread presence of uranium oxide fuel particles is unlikely to have influenced the environmental behaviour of 129I. Our findings have implications for long-term radiation dose from 129I in contaminated soils and the use of native, stable 127I as a proxy for the long-term fate of 129I.
Original languageEnglish
JournalScience of the Total Environment
Volume692
Pages (from-to)966-974
ISSN0048-9697
DOIs
Publication statusPublished - 2019

Keywords

  • Chernobyl
  • Iodine-127
  • Iodine-129
  • Soil

Cite this

Shaw, George ; Bailey, Elizabeth ; Crout, Neil ; Field, Lorraine ; Freeman, Stewart ; Gaschak, Sergey ; Hou, Xiaolin ; Izquierdo, Maria ; Wells, Claire ; Xu, Sheng ; Young, Scott. / Analysis of 129I and 127I in soils of the Chernobyl Exclusion Zone, 29 years after the deposition of 129I. In: Science of the Total Environment. 2019 ; Vol. 692. pp. 966-974.
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title = "Analysis of 129I and 127I in soils of the Chernobyl Exclusion Zone, 29 years after the deposition of 129I",
abstract = "The Chernobyl Exclusion Zone (CEZ) represents a unique natural laboratory that received significant 129I contamination across a range of soils and land-use types in a short time period in 1986. Data are presented on 129I and 127I in soil samples collected from highly contaminated areas in the CEZ in 2015. The geometric mean (GM) total concentration of stable iodine (127I) was 6.7 × 10−7 g g−1 and the (GM) total concentration of 129I was 2.39 × 10−13 g g−1, equivalent to 1.56 mBq kg−1. GM total 127I concentration is below the European average soil concentration of 3.94 × 10−6 g g−1, while 129I is significantly higher than the pre-Chernobyl activity concentration for 129I of 0.094 mBq kg−1. Significant differences were found in the extractability of native, stable 127I and 129I almost 30 years after the introduction of 129I to the soils. Both 127I and 129I were predominantly associated with alkaline-extractable soil organic matter, established using a three-step sequential extraction procedure. Whereas 127I was significantly correlated with gross soil organic matter (measured by loss on ignition), however, 129I was not. The ratio of 129I/127I was significantly lower in extracts of soil organic matter than in more labile (soluble and adsorbed) fractions, indicating incomplete equilibration of 129I with native 127I in soil humic substances after 29 years residence time in the CEZ soils. The initial physico-chemical form of 129I in the CEZ soils is unknown, but the widespread presence of uranium oxide fuel particles is unlikely to have influenced the environmental behaviour of 129I. Our findings have implications for long-term radiation dose from 129I in contaminated soils and the use of native, stable 127I as a proxy for the long-term fate of 129I.",
keywords = "Chernobyl, Iodine-127, Iodine-129, Soil",
author = "George Shaw and Elizabeth Bailey and Neil Crout and Lorraine Field and Stewart Freeman and Sergey Gaschak and Xiaolin Hou and Maria Izquierdo and Claire Wells and Sheng Xu and Scott Young",
year = "2019",
doi = "10.1016/j.scitotenv.2019.07.319",
language = "English",
volume = "692",
pages = "966--974",
journal = "Science of the Total Environment",
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Shaw, G, Bailey, E, Crout, N, Field, L, Freeman, S, Gaschak, S, Hou, X, Izquierdo, M, Wells, C, Xu, S & Young, S 2019, 'Analysis of 129I and 127I in soils of the Chernobyl Exclusion Zone, 29 years after the deposition of 129I', Science of the Total Environment, vol. 692, pp. 966-974. https://doi.org/10.1016/j.scitotenv.2019.07.319

Analysis of 129I and 127I in soils of the Chernobyl Exclusion Zone, 29 years after the deposition of 129I. / Shaw, George; Bailey, Elizabeth; Crout, Neil; Field, Lorraine; Freeman, Stewart; Gaschak, Sergey; Hou, Xiaolin; Izquierdo, Maria; Wells, Claire; Xu, Sheng; Young, Scott.

In: Science of the Total Environment, Vol. 692, 2019, p. 966-974.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Analysis of 129I and 127I in soils of the Chernobyl Exclusion Zone, 29 years after the deposition of 129I

AU - Shaw, George

AU - Bailey, Elizabeth

AU - Crout, Neil

AU - Field, Lorraine

AU - Freeman, Stewart

AU - Gaschak, Sergey

AU - Hou, Xiaolin

AU - Izquierdo, Maria

AU - Wells, Claire

AU - Xu, Sheng

AU - Young, Scott

PY - 2019

Y1 - 2019

N2 - The Chernobyl Exclusion Zone (CEZ) represents a unique natural laboratory that received significant 129I contamination across a range of soils and land-use types in a short time period in 1986. Data are presented on 129I and 127I in soil samples collected from highly contaminated areas in the CEZ in 2015. The geometric mean (GM) total concentration of stable iodine (127I) was 6.7 × 10−7 g g−1 and the (GM) total concentration of 129I was 2.39 × 10−13 g g−1, equivalent to 1.56 mBq kg−1. GM total 127I concentration is below the European average soil concentration of 3.94 × 10−6 g g−1, while 129I is significantly higher than the pre-Chernobyl activity concentration for 129I of 0.094 mBq kg−1. Significant differences were found in the extractability of native, stable 127I and 129I almost 30 years after the introduction of 129I to the soils. Both 127I and 129I were predominantly associated with alkaline-extractable soil organic matter, established using a three-step sequential extraction procedure. Whereas 127I was significantly correlated with gross soil organic matter (measured by loss on ignition), however, 129I was not. The ratio of 129I/127I was significantly lower in extracts of soil organic matter than in more labile (soluble and adsorbed) fractions, indicating incomplete equilibration of 129I with native 127I in soil humic substances after 29 years residence time in the CEZ soils. The initial physico-chemical form of 129I in the CEZ soils is unknown, but the widespread presence of uranium oxide fuel particles is unlikely to have influenced the environmental behaviour of 129I. Our findings have implications for long-term radiation dose from 129I in contaminated soils and the use of native, stable 127I as a proxy for the long-term fate of 129I.

AB - The Chernobyl Exclusion Zone (CEZ) represents a unique natural laboratory that received significant 129I contamination across a range of soils and land-use types in a short time period in 1986. Data are presented on 129I and 127I in soil samples collected from highly contaminated areas in the CEZ in 2015. The geometric mean (GM) total concentration of stable iodine (127I) was 6.7 × 10−7 g g−1 and the (GM) total concentration of 129I was 2.39 × 10−13 g g−1, equivalent to 1.56 mBq kg−1. GM total 127I concentration is below the European average soil concentration of 3.94 × 10−6 g g−1, while 129I is significantly higher than the pre-Chernobyl activity concentration for 129I of 0.094 mBq kg−1. Significant differences were found in the extractability of native, stable 127I and 129I almost 30 years after the introduction of 129I to the soils. Both 127I and 129I were predominantly associated with alkaline-extractable soil organic matter, established using a three-step sequential extraction procedure. Whereas 127I was significantly correlated with gross soil organic matter (measured by loss on ignition), however, 129I was not. The ratio of 129I/127I was significantly lower in extracts of soil organic matter than in more labile (soluble and adsorbed) fractions, indicating incomplete equilibration of 129I with native 127I in soil humic substances after 29 years residence time in the CEZ soils. The initial physico-chemical form of 129I in the CEZ soils is unknown, but the widespread presence of uranium oxide fuel particles is unlikely to have influenced the environmental behaviour of 129I. Our findings have implications for long-term radiation dose from 129I in contaminated soils and the use of native, stable 127I as a proxy for the long-term fate of 129I.

KW - Chernobyl

KW - Iodine-127

KW - Iodine-129

KW - Soil

U2 - 10.1016/j.scitotenv.2019.07.319

DO - 10.1016/j.scitotenv.2019.07.319

M3 - Journal article

VL - 692

SP - 966

EP - 974

JO - Science of the Total Environment

JF - Science of the Total Environment

SN - 0048-9697

ER -