Biochar Assisted Phyto-stabilization of Cd and Pb Contaminated Mining Soil Using Kenaf (Hibiscus cannabinus L.)

Soil heavy metal pollution has become a worldwide environmental issue; however, remediation of contaminated soils using biochar could be an eco-friendly approach to rehabilitate these soils by reducing their adverse effects. A pot experiment was carried out to determine the effectiveness of biochar derived from corn straw (CSB) at different application rates (0% as control, 1%, 3%, and 5% w/w) on the plant growth, oxidative stress, Cd and Pb uptake and transfer, and the soil properties. Addition of CSB notably improved the plant growth in terms of fresh weight, dry weight, plant height, stem diameter, and chlorophyll (SPAD values), while reduced available Cd and Pb contents in the soil. Moreover, prominent reduction was detected in kenaf root and shoot Cd and Pb contents. The chlorophyll in leaves was significantly high at 3% CSB rate as compared to control. Furthermore, 3% CSB application caused a significant decrease in oxidative stress. CSB demonstrated positive results for Cd and Pb immobilization in mining soil by increasing soil pH and electrical conductivity as well as by reducing the Cd and Pb availability and uptake in plants. A negative correlation was recorded between DTPA extractable Cd/Pb and pH of soil that depend on CSB application rate. These results highlight the significance of kenaf cultivation using CSB in remediation of Cd and Pb contaminated mining soil and provide a scientific foundation to develop a practical strategy towards biochar application for contaminated lands.

Automated summary

Biochar is an effective method for remediating soil heavy metal pollution by improving plant growth and reducing metal availability in soil.