Risk Assessment of Biochar in Soil and Aquatic Ecosystem

Biochar as a promising environmental remediation technology can be inevitably diffused into environment, posing a threat to soil and aquatic ecological ecosystem. Therefore, it is necessary to summarize the negative effect of biochar on soil and aquatic organisms, which is beneficial for understanding the potential risks of biochar. In this chapter, negative impacts of biochar on terrestrial plants, soil organisms, and soil microorganisms are firstly introduced. As for aquatic ecosystem, how exposure conditions (exposure concentration and time) and physiochemical properties of biochar caused toxicity of phytoplankton is mainly discussed. It is found that pyrolysis temperature, biomass source, particle size, and fractions of biochar are main factors to influence phytoplankton (i.e., algae) growth, photosynthesis, and oxidative stress. In addition to single effect, the combined effects of biochar and pollutants are also reviewed due to the high absorption ability of biochar. Finally, the potential measurements for risk avoidance of biochar are suggested to design safe biochar for large application in environmental remediation.