Giant crater from the explosion of a Russian air bomb in the Kukhari village, Kyiv area, Ukraine, … [+]
In 2006, geographers Joseph Hupy and Randy Schaetzel introduced the term “bombturbation” to describe the geological features associated with bomb craters. The authors suggest that the common use of bombs and explosives in modern warfare will leave recognizable traces in Earth’s fossil record.
The two scientists visited World War I battlefields in France to investigate how explosive ammunition ranging from grenades to heavy artillery modified the landscape. Explosions fractured the shallow bedrock and redeposited soil and rock fragments on the outer rim of the crater, forming lenses of gravel-ejecta. With time, fine-grained clay and litter from the slowly returning vegetation was deposited inside the craters. Earthworms living in the litter and decaying plants release organic acids, accelerating the chemical weathering of the underlying bedrock. The changes in landscape morphology, soil thickness and erosion rate are significantly enough to be still recognizable centuries after the war ended.
For the new study, investigators examined soil in bomb craters in a small, wooded area in the Pas-de-Calais region in France that was subject to considerably less intense fire than previously studied battlefield areas. Despite the lack of classic bombturbation, the researchers still found traces of the battle.
They found that the bomb craters’ soil contains elevated levels of copper and lead in some cases. This contamination derives from fragments of metallic shells and exploded ammunition.
In addition to revealing potentially dangerous compounds in the soil of European areas involved in past wars, the findings may also have implications for the modern-day battlefields, such as those in Ukraine, a country that produces much of the world’s grain supply and has been subjected to widespread artillery damage from Russian attacks.
Military operations can contaminate the soil with lead and mercury released by burning fuel, organic compounds from oil spills, and metals like lithium, aluminum, and nickel from vehicles and other machinery. Together with metals and fragments from exploded ammunition, these fields may be dangerously contaminated in the long-term, and chemical traces of the ongoing war could be preserved in the fossil record for millions of years.
The paper “Legacy of war: pedogenesis divergence and heavy metal contamination on the WWI front line a century after battle” is published in the European Journal of Soil Science (2022).
