Li Yao, Zhu Yulong, Liu Xingang, Wu Xiaohu, Dong Fengshou, Xu Jun, Zheng Yongquan
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, PR China.
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, PR China.
Chemosphere. 2017 Mar;171:185-191. doi: 10.1016/j.chemosphere.2016.12.071. Epub 2016 Dec 18.
Biochars can significantly sorb pesticides, and reduce their bioavailability in agricultural soils. In this study, the effects of a type of biochar (BC500) on the sorption, degradation, bioaccumulation and bioavailability of thiacloprid, which is a commonly used insecticide, were investigated. The thiacloprid sorption constant (K values) increased by 14 times after 2% BC500 application, and the degradation of the insecticide decreased with increasing amounts of the biochars in the soil. Coupled with the exhaustive extraction and single-point Tenax method, the bioavailability of thiacloprid was predicted in the presence of the biochar. In soils amended with BC500, the thiacloprid concentrations accumulated in Tenax correlated well with those observed in earthworms (R = 0.887), whereas the concentrations extracted by exhaustive method followed a less significant relationship with those in earthworms (R = 0.624). The results of Tenax extractions and earthworm bioassays indicate that biochar reduces the bioavailability of thiacloprid in soil, but the delayed degradation and increased earthworm accumulation in aged biochar-amended soil imply that the environmental risks of biochar application to earthworms remain.
生物炭能显著吸附农药，并降低其在农业土壤中的生物有效性。在本研究中，考察了一种生物炭（BC500）对常用杀虫剂噻虫啉的吸附、降解、生物累积及生物有效性的影响。施加2%的BC500后，噻虫啉的吸附常数（K值）增加了14倍，土壤中该杀虫剂的降解随生物炭施用量的增加而降低。结合 exhaustive提取法和单点Tenax法，预测了生物炭存在时噻虫啉的生物有效性。在用BC500改良的土壤中，Tenax中积累的噻虫啉浓度与蚯蚓体内观察到的浓度具有良好的相关性（R = 0.887），而通过exhaustive提取法提取的浓度与蚯蚓体内的浓度相关性较弱（R = 0.624）。Tenax提取和蚯蚓生物测定结果表明，生物炭降低了噻虫啉在土壤中的生物有效性，但老化生物炭改良土壤中噻虫啉降解延迟和蚯蚓体内累积增加表明，施用生物炭对蚯蚓仍存在环境风险。
