Effect of biochar on tungsten bioavailability and uptake grown in a soil with artificially tungsten contaminated

Tungsten (W) is an emerging contaminant because of its potential toxicity to humans, and biochar (BC) is widely used for soil heavy metal remediation. However, W-biochar-plant interactions remain unknown. The objective of the study was to evaluate the effect of rice-husk BC on W uptake by lettuce. Different levels of BC (0%, 1%, 2% and 5% w/w) were incorporated into the soil and incubated for 60 days. The result shows that BC application immobilized W in soil, and transformed acid extractable fraction and reducible fraction to residual fraction with unstudied mechanism. Meanwhile, BC application increased the shoot height, root length, biomass, and chlorophyll of lettuce compared with control treatment. As compared to control, the accumulation of W in shoot and root was decreased, and the lowest translocation factor (root to shoot) was observed in 5% BC treatment. The results suggested that the main profit of BC to reduce mobilizing of W to proximal water. Besides, the application of BC was effective in W immobilization and reducing uptake to lettuce.