2023-11-17 19:43:02
By heating the ground to more than 400°C, the fire modifies its chemistry, particularly that of the metals it contains. They can then become more toxic and pollute rivers when rain carries them to them…
When a fire ravages a forest, the ground is white hot. Its temperature can reach 800°C, and its chemistry can be modified. What happens if the earth contains metals? Researchers have asked this question in New Caledonia. In a third of soils, the concentration of metals is indeed high, particularly nickel and chromium. And human-caused fires burn constantly on the island, especially during the El Niño climatic phenomenon, through the tall grass and shrubs of the maquis.
« We took samples from three different soils, and the samples were heated to 200 °C, 400 °C and 600 °C in the laboratory », explains Farid Juillot, from the Research Institute for Development (IRD) in Nouméa. With Caledonian doctoral student Gaël Thery, researchers from the CNRS and four French universities, the geochemist coordinated a study, the results of which are published in the journal Applied Geochemistry .
We estimated from what quantity of suspended matter in a river, the drinking threshold is exceeded for chromium
Farid Juillot, from the Research Institute for Development (IRD) in Nouméa
When chrome…
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