Fan Yuchao, Sheng Xue, Xia Ruizhi, Dong Tingting, Zhang Shiwen, Feng Xiujuan, Zhou Jun, Fang Guodong, Cui Hongbiao
Joint National-Local Engineering Research Centre for Safe and Precise Coal Mining (Anhui University of Science and Technology), Huainan, 232001, China.
School of Earth and Environment, Anhui University of Science and Technology, Huainan, 232001, China.
Bull Environ Contam Toxicol. 2025 Jul 29;115(2):21. doi: 10.1007/s00128-025-04094-x.
Biochar is extensively used in environmental remediation, but the effects of aging on the immobilization of cadmium (Cd) in contaminated soils treated with biochars containing various endogenous Cd is unclear. This study investigated the effects of simulated acid rain (SAR) aging on the bioavailability of Cd in soil amended with two rice straw biochars (RSBs, marked as RS1 and RS2) and two sludge biochars (SSBs, marked as SS1 and SS2) under flooding condition. Results showed that SSBs had higher specific surface area, ash, silicate contents, and more functional groups than those of RSBs. The total Cd in the biochars followed the order of RS1 > RS2 > SS1 > SS2. SSBs applications significantly decreased soil CaCl-extractable and acid-soluble Cd by 51.3%-78.6% and 4.51%-5.44% after a 30-day incubation with 70% water holding capacity than the control. SAR aging significantly decreased the soluble, CaCl-extractable, and acid-soluble Cd in all treatments compared with those before aging. This may be due to the decreased effects from the formation of insoluble Cd sulfide and the adsorption of Cd by Fe-Mn (oxidro)oxides under continuous flooding condition was outweighed the increase in soluble Cd caused by SAR accumulation. Moreover, the soluble, CaCl-extractable, and acid-soluble Cd in RSBs treated soils were significantly higher than those of SSBs after SAR aging. The study indicated that the RSBs with high endogenous Cd posed greater environmental risks, thus the long-term effects of biochar application in soil need further study.
生物炭被广泛应用于环境修复，但老化对含有不同内源镉的生物炭处理的污染土壤中镉固定化的影响尚不清楚。本研究调查了模拟酸雨（SAR）老化对淹水条件下两种稻草生物炭（RSBs，标记为RS1和RS2）和两种污泥生物炭（SSBs，标记为SS1和SS2）改良土壤中镉生物有效性的影响。结果表明，SSBs比RSBs具有更高的比表面积、灰分、硅酸盐含量和更多的官能团。生物炭中的总镉含量顺序为RS1＞RS2＞SS1＞SS2。与对照相比，在持水量70%的条件下培养30天后，施用SSBs显著降低了土壤中氯化钙可提取态镉和酸溶态镉，分别降低了51.3%-78.6%和4.51%-5.44%。与老化前相比，SAR老化显著降低了所有处理中可溶态、氯化钙可提取态和酸溶态镉的含量。这可能是由于在连续淹水条件下，形成不溶性硫化镉的影响减弱，以及铁锰（氧化）氧化物对镉的吸附作用超过了SAR积累导致的可溶态镉增加。此外，SAR老化后，RSBs处理土壤中的可溶态、氯化钙可提取态和酸溶态镉显著高于SSBs处理土壤。该研究表明，具有高内源镉的RSBs带来了更大的环境风险，因此生物炭在土壤中应用的长期影响需要进一步研究。
