4 / 2021-05-06 16:15:57

Negative impacts of biochar on soil: Potential toxic chemical and controlling factors

biochar,negtive interaction,soil ecosystem,remdiation,toxic mechanism

Biochars are widely used for soil amendment, with benefits of reducing carbon emissions and improving the soil quality. However, the potential toxic chemicals in biochars (e.g., heavy metals, polycyclic aromatic hydrocarbons, volatile organic compounds, and environmentally persistent free radicals) may be harmful to the soil ecosystem. Furthermore, the formation mechanism and controlling factors of these potential toxic chemicals are complicated due to the complex nature of biomass and different production conditions. Understanding the formation process and ecotoxicity of the potential toxic chemicals in biochar is essential to avoiding the negative effects of biochar on soil. However, no comprehensive review of the potential toxic chemicals in biochars and their negative effects on soil has been conducted. Herein, we discussed the formation mechanism of potential toxic chemicals in biochars, particularly the environmentally persistent free radical because of its strong reducing or oxidizing property. We further reviewed the negative effects of biochar on flora, fauna, and microorganisms and discussed the underlying mechanism. This review provided useful information for producing an environment-friendly biochar and avoiding the negative effect of biochar application as soil amendment.