Phytostabilizing Effect of Biochars on Remediating Heavy Metals in Mine Spoil Soils.

Biochars ability to sequester metals has caught the attention of the mine reclamation sector. Biochar has gained global interest as an amendment to improve the fertility, chemical, and physical properties of degraded agricultural soils. Numerous research investigations have confirmed that biochars can increase soil carbon sequestration, contain critical plant nutrients, and have binding mechanisms to sequester metals. It is proposed that biochar is a suitable amendment to remediate heavy metals in mine spoils, as well as improve chemical conditions for enhanced plant growth. Better plant growth will improve phytostabilization, increase containment of metal-laden sediment, while also reducing potential metal uptake by plants. As such, utilization of a biochar with appropriate chemical and physical characteristics is crucial for effective binding of heavy metals while also improving plant growth conditions in the mine spoils. Using mine spoils, we conducted laboratory and greenhouse experiments to determine the ability of biochar specifically designed to improve their pH, nutrient content, and sequestration of heavy metals. Moreover, we examined the capacity of designer biochars to limit heavy metal uptake by a grass (e.g., wild blue rye) grown in mine spoils. Preliminary results showed that our designer biochars did increase pH of acid mine spoils, improved the content of critical plant nutrients (e.g., phosphorus and potassium), and reduced heavy metal (e.g. zinc, manganese, etc.) plant uptake.