Biochar Extracts Can Modulate the Toxicity of Persistent Free Radicals in the Nematode Caenorhabditis elegans

As an effective soil amendment, biochars require a comprehensive ecological evaluation before they can be widely used in agriculture because endogenous contaminants, such as environmentally persistent free radicals (EPFRs), certainly pose risk to invertebrates. In this study, Caenorhabditis elegans (C. elegans) was model organism investigate the neurotoxicity of two rice straw pyrolyzed at 500 and 700 °C. After 24 h exposure unwashed biochar, washed leaching fluids (supernatants), neurobehavioral parameters C. were determined liquid toxicity test. The results showed that °C biochar particles significantly impaired locomotion prolonged defecation interval concentration 4 g·well−1, while supernatants caused no apparent impairment. Supporting this, electron paramagnetic resonance (EPR) intensity EPFRs stronger than corresponding particles. This indicates that, test, EPR signal alone is not indicative particle toxicity. accessibility activity should considered. Dissolved organic matter (DOM) observed fluids. neurotoxic alleviated after re-addition suggesting dissolved materials modulate reactivity phase. study suggests process may increase when field environment.