The effects of remediation under different substrate conditions and environmental behavior of heavy metals

This study analyzed changes in physicochemical properties of the soil under various substrate conditions, as well as the interactions between <i>ryegrass</i> and heavy metals. Results indicated that biochar significantly improved soil physicochemical properties, such as an increase in electrical conductivity by 34.8%, enhancement of pH from 7.13 to 7.32, and augmentation in organic matter by 152%. Moreover, readily available phosphorus and alkali-hydrolyzable nitrogen increased by 237% and 122% respectively, while soil cation exchange capacity rose by 135%. This contributes to plant growth and the maintenance of soil fertility. The biochar addition also led to a decrease in the proportion of fine soil particles by 20%, significantly enhancing structure and stability of soil aggregates and promoting the formation of larger aggregates, crucial for improving soil aeration, water retention, and root permeability. The addition of biochar notably altered the chemical forms of heavy metals in soil, promoting their transformation from bioavailable forms to more stable and less toxic forms, effectively reducing the bioavailability and mobility of heavy metals, and decreasing their environmental toxicity. The addition of biochar, by changing the chemical forms of heavy metals, not only enhanced germination rate of <i>ryegrass</i> seeds but also improved the overall growth state of <i>ryegrass</i>. This study introduces a novel biochar-ryegrass system for phytoremediation, effectively enhancing soil quality and reducing the bioavailability of heavy metals. By demonstrating significant improvements in soil properties and heavy metal stabilization, this research provides a practical and environmentally friendly approach to soil remediation, offering new insights and methods for managing soil contamination. Introduced a biochar-<i>ryegrass</i> system for enhanced heavy metal remediationExplored biochar’s impact on soil physicochemical properties and metal bioavailabilityAssessed heavy metal uptake of <i>ryegrass</i> in contaminated substrates with biochar additionProvided theoretical insights into biochar’s role in improving phytoremediation efficiency Introduced a biochar-<i>ryegrass</i> system for enhanced heavy metal remediation Explored biochar’s impact on soil physicochemical properties and metal bioavailability Assessed heavy metal uptake of <i>ryegrass</i> in contaminated substrates with biochar addition Provided theoretical insights into biochar’s role in improving phytoremediation efficiency