Soil & Land

Lethal discovery in soil affected by bushfire

Professor Ed Burton of Southern Cross Geoscience is looking at the levels of a toxic element in bushfire affected soil.

Geoscientists from Southern Cross University in northern NSW have made a world-first discovery in revealing the lethal legacy of soils scorched by bushfires.

The team, led by Professor Ed Burton, found the naturally occurring metal chromium-3 can be converted by extreme bushfire heat into the highly toxic and cancerous chromium-6.

American environmentalist Erin Brockovich achieved international prominence when she discovered high concentrations of chromium-6 in the water supply of her home town in southern California.

Professor Burton’s breakthrough research has confirmed bushfire temperatures of up to 1,000 degrees can create a real danger to human health long after the flames are extinguished.

“We’ve seen bushfires create conditions in the surface soil that transform the safe, naturally occurring chromium-3 into the toxic, cancer-causing chromium-6,” Professor Burton said.

“Chromium-6 can cause lung cancer and leach into waterways.”

Professor Burton, an expert on the geochemistry and mineralogy of soils, sediments and groundwater systems, said frontline firefighters are immediately at risk, but the contamination of water within catchment areas posed a wider threat.

“We know that firefighters have higher incidences of chromium in their urine and are more susceptible to cancer than other groups.

“This research is trying to predict with greater accuracy the potential harm of this carcinogenic toxin and to mitigate the risk to human health by seeking to determine the reach and duration of the post-fire danger zone.

“The role of high temperatures in potential chemical contamination has been underplayed, so it’s also important to learn which soils are most prone to contamination, and for how long.”

While chromium-3 is a healthy nutrient in humans for insulin, sugar and lipid metabolism, its transformation into the DNA-damaging chromium-6 in bushfires was discovered when Professor Burton’s team used the Australian Synchrotron particle separator in Melbourne to shine a highly-focussed light – millions of times brighter than the sun – on a series of soil and mineral samples.

Source: Southern Cross University