Study finds Cold War guilty for radioactive wild boars

What do Chernobyl and the Cold War have to do with reduced consumption of wild boars and venison meat? How concerning is their overpopulation?
Amal Jos Chacko
Representational image of a wild boar.jpg
Representational image of a wild boar.

ViktorCap/iStock 

In the enchanting woods of Germany and Austria roam shaggy-haired, tusked wild boars freely, embodying the picturesque charm of Europe's wilderness.

However, a recent press release reveals research that points to a hidden danger posing a threat to both wildlife and human health beneath their seemingly robust appearance. These majestic game animals— once considered a delicacy— carry a sinister secret in their meat - radioactive cesium.

Although the discovery of this unsettling reality left scientists blaming the Chernobyl disaster of 1986 initially, new research has suggested a startling revelation - the contamination of these wild boars can be traced back not only to Chernobyl but also to the nuclear weapons testing of the Cold War era 60 to 80 years ago, shedding new light on a radioactive mystery.

Uncovering the radioactive source

Radioactive cesium, a hazardous byproduct of both nuclear weapons explosions and nuclear energy production, is known to be a perilous threat to public health when it infiltrates the environment.

The catastrophe at Chernobyl, which occurred 37 years ago, released a significant pulse of radioactive cesium contamination across Europe. While most of this radioactivity originated from cesium-137, a more enduring form known as cesium-135 is also generated during nuclear fission.

Over time, cesium-137 levels have dwindled in most game animals, yet wild boars' radioactivity remains disturbingly unchanged. This persistent contamination has led to their meat exceeding regulatory limits for consumption in some areas, causing a decline in hunting and contributing to the overpopulation of these animals across Europe.

Curious about the unyielding radioactive cesium levels, a team of scientists, including Georg Steinhauser and Bin Feng, embarked on a quest for answers. They collaborated with local hunters and collected wild boar meat from various regions in Southern Germany.

Employing a gamma-ray detector, they meticulously measured the cesium-137 levels in the samples. To ascertain the source of this radioactivity, the team employed a sophisticated mass spectrometer to compare the ratios of cesium-135 to cesium-137, a clear indicator of the contamination source. A higher ratio implicated nuclear weapons explosions, whereas a lower ratio pointed to nuclear reactors.

The results were nothing short of astonishing.

A staggering 88 percent of the 48 meat samples observed exceeded German regulatory limits for radioactive cesium in food. For those samples with elevated levels, the researchers calculated that nuclear weapons testing from the mid-20th century contributed between 10 percent and 68 percent of the contamination.

In some cases, the amount of cesium solely from weapons testing exceeded regulatory limits. This revelation suggests that the nuclear tests conducted during the Cold War era were an underestimated source of radioactive cesium in German soil, further compounded by the uneven impact of the Chernobyl accident.

These contaminants, absorbed by the wild boars' favored food, underground truffles, have fueled their continued radioactivity, raising concerns about food safety for future decades.

Implications for the ecosystem

The implications of this research extend far beyond the seemingly innocent wild boars of Germany and Austria. As the study highlights, the contamination of these animals threatens their own well-being and the Bavarian forests they inhabit.

The fact that these animals are no longer hunted for their meat has led to unsustainable population growth, posing a severe ecological challenge. With radioactivity persisting in the environment and Chernobyl's legacy seeping further into the soil, truffles that serve as the primary food source for wild boars continue to be contaminated, perpetuating this disturbing cycle.

The study, published in the peer-reviewed journal Environmental Science and Technology, underscores the need for ongoing monitoring and remediation efforts to mitigate the risks posed to wildlife and humans.

It further warns that future nuclear accidents or explosions could exacerbate this contamination, jeopardizing food safety and the delicate balance of ecosystems for generations to come.

Study 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–1 137Cs, 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.

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