Environmental concern on biochar: capture, then what?

Biochar is receiving increasing attention as soil amendment. A booming expansion is expected to sharply increase the amount of biochar usage around the world. When we are on the way to change the environment by adding biochar into soil, it is worthwhile to evaluate comprehensively environmental considerations before making excessive use of it in soil. Biochar in soil can effectively retain a wide range of toxic substances through sorption and other physicochemical reactions. Nevertheless, this process usually includes decreased mobility rather than significant chemical reduction of target compounds. Biochar tends to become the sink of soil pollutants. The changing soil environment can result in the release of toxic compounds from biochar in the long term. Biochar can be deactivated by clogged pores or decreasing sorption capacity. Once biochar is mixed with soils, it is difficult to separate them again. It is important to make a deliberate decision before action.