Naomi Rintoul-Hynes, Senior Lecturer in Soil Science and Environmental Management at Canterbury Christ Church University, and MSc student Owain Williams, examined soil in bomb craters in the Pas-de-Calais region in France, with the study’s results published in the European Journal of Soil Science.

The findings uncovered long-term heavy metal contamination on the World War One front line, a century after battle and suggests bomb craters’ soil contains elevated levels of copper and lead.

British, French and German troops fired 1.45 billion bullets during World War One, and a great deal of these bullets – and other material associated with warfare - were left behind in the soil. More than 30 elements are associated with modern warfare, although the main heavy metals found in ammunition are lead, copper and zinc.

In addition to revealing potentially dangerous compounds in the soil of European areas involved in the past war, the findings may also have implications for the current war in Ukraine, a country that produces much of the world’s grain supply and has been subjected to widespread artillery damage from Russian attacks.

Shelling has also disrupted the ecosystems of microorganisms that turn soil materials into crop nutrients such as nitrogen while tanks have compressed the earth, making it harder for roots to flourish.

Dr Naomi Rintoul Hynes explained the implications for modern-day battlefields and is currently working with academic colleagues in Ukraine to examine soil that has been damaged from Russian artillery.

“As well as the short-term impacts in Ukraine to agriculture through crop supply chain issues, these fields may be dangerously contaminated by munitions in the long-term – possibly for 100 years or more,” she said.

“In Ukraine, my concern is that conflict will lead to higher concentrations of potentially harmful elements (i.e. lead, copper, zinc, antimony, uranium, arsenic and chromium) in the soils that could then bioaccumulate in the crops that are being eaten by Ukrainian people and are exported to other countries. However, it’s also important not to scaremonger without having the data to understand the extent of any contamination.

“Lead, for example, has a half-life of 700 years or more, meaning it may take that long for its concentration in the soil to decrease by half. Such toxins can accumulate so much in plants growing there that human health may become affected.”

Read the full research report here.