Disproportionately High Contributions of 60 Year Old Weapons-¹³⁷Cs Explain the Persistence of Radioactive Contamination in Bavarian Wild Boars

authored by

Felix Stäger, Dorian Zok, Anna Katharina Schiller, Bin Feng, Georg Steinhauser

Abstract

Radionuclides released from nuclear accidents or explosions pose long-term threats to ecosystem health. A prominent example is wild boar contamination in central Europe, which is notorious for its persistently high ¹³⁷Cs levels. However, without reliable source identification, the origin of this decades old problem has been uncertain. Here, we target radiocesium contamination in wild boars from Bavaria. Our samples (2019-2021) range from 370 to 15,000 Bq·kg^-1137Cs, thus exceeding the regulatory limits (600 Bq·kg^-1) by a factor of up to 25. Using an emerging nuclear forensic fingerprint, ¹³⁵Cs/¹³⁷Cs, we distinguished various radiocesium source legacies in their source composition. All samples exhibit signatures of mixing of Chornobyl and nuclear weapons fallout, with ¹³⁵Cs/¹³⁷Cs ratios ranging from 0.67 to 1.97. Although Chornobyl has been widely believed to be the prime source of ¹³⁷Cs in wild boars, we find that “old” ¹³⁷Cs from weapons fallout significantly contributes to the total level (10-68%) in those specimens that exceeded the regulatory limit. In some cases, weapons-¹³⁷Cs alone can lead to exceedances of the regulatory limit, especially in samples with a relatively low total ¹³⁷Cs level. Our findings demonstrate that the superposition of older and newer legacies of ¹³⁷Cs can vastly surpass the impact of any singular yet dominant source and thus highlight the critical role of historical releases of ¹³⁷Cs in current environmental pollution challenges.

Organisation(s)

Centre for Radiation Protection and Radioecology

External Organisation(s)

TU Wien (TUW)

Type

Article

Journal

Environmental Science and Technology

Volume

57

Pages

13601–13611

No. of pages

11

ISSN

0013-936X

Publication date

12.09.2023

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

General Chemistry, Environmental Chemistry

Sustainable Development Goals

SDG 12 - Responsible Consumption and Production

Electronic version(s)

https://doi.org/10.1021/acs.est.3c03565 (Access: Open)