Fire-induced effects on the bioavailability of potentially toxic elements in a polluted agricultural soil: implications for Cr uptake by durum wheat plants

• Published in: Environmental science and pollution research international Vol. 30; no. 3; pp. 6358 - 6372
• Main Authors: Rascio, Ida, Gattullo, Concetta Eliana, Porfido, Carlo, Allegretta, Ignazio, Spagnuolo, Matteo, Tiziani, Raphael, Celletti, Silvia, Cesco, Stefano, Mimmo, Tanja, Terzano, Roberto
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-01-2023
• Subjects: Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Biological Availability; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental Monitoring - methods; Humans; Lead - analysis; Metals, Heavy - analysis; Research Article; Risk Assessment; Soil - chemistry; Soil Pollutants - analysis; Triticum; Waste Water Technology; Water Management; Water Pollution Control; Soil fire; Polluted soil; Cr(VI); Chromium translocation; Potentially toxic elements; Chromium uptake
• ISSN: 0944-1344; 1614-7499; 1614-7499
• DOI: 10.1007/s11356-022-22471-5

Fire events can modify the distribution and speciation of potentially toxic elements (PTEs) in soil, especially if they are associated to organic matter (OM). In fact, OM can undergo substantial structural modifications at high temperatures, up to the complete mineralization. The present study aims to investigate the changes of PTEs’ bioavailability to durum wheat (
Triticum durum
Desf.) plants after simulating fire events (up to 300 °C and 500 °C) in an agricultural soil polluted by Cr, Zn, Cu, and Pb. The PTEs’ uptake and allocation in plant tissues were assessed using the RHIZOtest system. After the fire simulations, no evident risk of accumulation and translocation in plants was observed for Zn, Pb, and Cu. Conversely, a high accumulation in roots and a significant translocation to shoots were observed for Cr, which reached concentrations of 829 mg kg
−1
in roots and 52 mg kg
−1
in shoots at 500 °C. Additional experimental evidence suggested that Cr was taken up by plants grown on heated soils as Cr(VI). Once acquired by roots, only a small part of Cr (up to 6%) was translocated to shoots where it was likely present as mobile forms, as evidenced by micro X-ray fluorescence (µ-XRF) analyses. Overall, the results obtained provide evidence that the high temperatures occurring during fire events can increase the mobility and bioavailability of certain PTEs transforming apparently safe environments into potentially dangerous sources of pollution. These processes can ultimately affect the human health through the food chain transfer of PTEs or their migration into surface water and groundwater.