Effects of iron plaque and fatty acids on the transfer of BDE-209 from soil to rice under iron mineral Fenton-like oxidation condition

To understand the effect mechanisms of iron plaque and fatty acids on the migration of PBDEs from soil to rice (Oryza sativa), pot experiments were conducted in the soil spiked with decabromodiphenyl ether (BDE-209) under the conditions of tourmaline and nano-goethite Fenton-like treatments. The results showed that iron mineral Fenton-like oxidation could effectively remove BDE-209 from rhizosphere soil, the highest removal rate obtained 89.29% with the addition of 0.4 mmol/L H₂O₂ and 8 g nano-goethite (G + 3H group). Iron mineral Fenton-like oxidation could produce iron plaque (IP) on rice roots and accumulate a part of contaminants on the surface of IP, further weakening BDE-209 uptake in the plants. Additionally, the occurrence of fatty acid variation induced by BDE-209 stress, iron mineral Fenton-like oxidation at high concentrations of H₂O₂ with 0.4 mmol/L affected the distribution of fatty acids in plant tissues, especially for C_18:0 fatty acid. While the IP on rice roots prevented the BDE-209 into plant, it was also closely related to the distribution of fatty acids in rice, altering BDE-209 accumulation in the rice. To safely use the iron mineral Fenton-like oxidation in the agricultural soil remediation, the safety of plant cells treated by mineral Fenton-like oxidation was evaluated using the transmission electron microscopy (TEM) and enzyme activity determination, which indicated that iron mineral Fenton-like oxidation would destroy the inner structures of plant cells, especially for G + 3H group.