The effectiveness of nanobiochar for reducing phytotoxicity and improving soil remediation in cadmium-contaminated soil

There is growing concern that Cd in soils can be transferred to plants, resulting in phytotoxicity and threats to human health via the food chain. Biochar has been reported to be a soil amendment capable of reducing the bioavailability of metals in soil by electrostatic interactions, ionic exchange and the specific binding of metal ions by surface ligands. To determine the effects of Cd contamination and nanobiochar on the growth characteristics of plants, the dynamics of Cd in soil were explored in Petri dish and pot experiments (0%, 0.2%, 0.5% and 1% nanobiochar), respectively. The diversity, distribution and composition of the bacterial community in treated soil were monitored by high-throughput sequencing. The results showed that the germination potential and height and weight of plants were significantly decreased in Cd-treated soil samples (P < 0.05). The Cd content of Brassica chinensis L. in the treated soil groups was lower than that in the untreated soil groups (P < 0.05) after nanobiochar application. The application of biochar significantly improved the microbial biomass, microorganism abundance and diversity of Actinobacteria and Bacteroidetes in Cd-contaminated soil and reduced the diversity of Proteobacteria, which was relatively more persistent than in the contaminated sites without biochar application. The results of this study provide theoretical and technical support for understanding the environmental behavior of nanopassivators, thus enhancing the role of biochar in the remediation of soil pollution.