Bamboo biochar helps minimize Brassica phytotoxicity driven by toxic metals in naturally polluted soils of four mine zones

Researchers have recently become interested in utilizing biochar amendment as an organic approach to enhance soil quality and minimize the mobility of toxic metals (TMs), which can help grow TM-tolerant plant species in polluted areas. A pot experiment was conducted to examine the efficacy of bamboo biochar (BB) in reducing the phytotoxicity of four unique mine-contaminated soil types. According to a completely randomized design (CRD), in four replications on Brassica juncea, a five-level bamboo biochar treatment (0 % Control, 2.5 % BB, 5 % BB, 7.5 % BB, and 10 % BB) was administered in naturally contaminated areas of Sarcheshmeh, Gol-Gohar, Chadormalu, and Anguran mines. The data show that Bamboo Biochar (BB) increased soil enzymatic activities (58 %), reformed soil structure, including pH (7 %) and electrical conductivity (EC) (51 %), and decreased the availability of TMs (Zn (37 %), Pb(34 %), Cd(51 %), Cu(34 %)), preventing accumulation in roots (42 %) and translocation to shoots (38 %). The phytochelatin (79 %), ascorbic acid (56 %), glutathione contents (57 %), and antioxidant (51 %) and glyoxalase activities (71 %) in B. juncea ultimately enhanced root-shoot dry biomass (44 %) and overall tolerance to TMs in mine-polluted soil (43 %). BB at 10 % might be used as a reliable soil amendment and natural metal immobilization adsorbent in the soil, as well as a suitable option for reducing oxidative stress caused by TMs in B. juncea plants, which are strong phytoremediation candidates in polluted soils. Future research endeavors might aim to discover cost-effective, efficient, and natural substances that can enhance and diminish environmental toxicity, eliminate soil contamination caused by heavy metals, and ultimately enhance human well-being. Keywords: Biochar Application; Soil amendment; Plant stress tolerance; Toxic metal; Phytoremediation