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The adverse effect of biochar to aquatic algae- the role of free radicals

Zhang, Ying, Yang, Ruixin, Si, Xiaohui, Duan, Xingwei, Quan, Xie
Environmental pollution 2019 v.248 pp. 429-437
Photobacterium phosphoreum, Pinus, Scenedesmus obliquus, adverse effects, algae, biochar, cell growth, chlorophyll, conifer needles, free radicals, heavy metals, hydroxyl radicals, luminescence, remediation, risk, soil, soil pollution, superoxide dismutase, toxicity, water pollution
The application of biochar in remediation and recovery of heavy metals and/or organic contaminants in water and soil is increasing. However, the adverse effect of biochar to aquatic organisms has not received enough attention. In this study, we conducted a study on the biotoxicity of biochar pyrolyzed from pine needle under oxygen-limited conditions. The toxicity of biochar was expressed with the following endpoints: cell growth, chlorophyll-a (Chl-a), reactive oxygen species (ROS), superoxide dismutase (SOD) content of Scenedesmus obliquus (S. obliquus) and the luminescence of Photobacterium phosphoreum (P. phosphoreum). Here, the effect of free radicals (FRs) contained in biochar was stressed. Our results show that the toxicity of biochar is significantly correlated with the concentration of FRs in biochar particles. Meanwhile, we found the FRs-containing biochar could induce the production of acellular ROS (such as ·OH) in water, which would also induce the production of interior cellular ROS in aquatic organisms. Our findings provide a new insight into the mechanism of toxicity aroused by biochar applications and aid in understanding its potential ecological risk.