中文摘要：

采用1％、2％和5％的生物炭钝化污染沉积物中的重金属，并研究生物炭修复对水体的生态影响．结果表明，生物炭添加后水体的pH值显著增大，上覆水和间隙水中溶解态cu、zn和Cd浓度均显著降低．1％（彤形）生物炭添加量使上覆水中溶解态Cu比对照降低了82．4％；在不同添加量下间隙水溶解态Zn降低幅度为11．7％-62．8％．通过BCR重金属形态分级发现沉积物中酸溶态重金属均有向残渣态转化的趋势．在5％生物炭添加量时，酸溶态Cu降低了73．08mg·kg^-1，降低幅度达到32．1％，而可氧化态Pb增加幅度达到67．8％．通过生物可利用实验（PBET）发现，当生物炭添加量为5％时，生物可利用性cu降低9．8％，Zn、Pb和Cd的生物可利用性也有不同程度降低．生物炭添加到沉积物后，用于植物毒性试验的家独行菜（Lepidium sativum）茎长呈现19．5％-25．7％的增加，根长也随之增加，说明生物炭降低了沉积物重金属的植物毒性．

英文摘要：

Heavy metals in contaminated sediments were immobilized by biochar with application rates of 1%, 2% and 5%, and the ecological impact of biochar remediation on aquatic environment was evaluated. The results indicated that biochar application led to significant increase of pH but significant decrease of dissolved Cu, Zn and Cd concentrations in the overlying water. Compared to the control, dissolved Cu concentration in the overlying water at biochar application rate of 1% （W/W） was reduced by 82.4%. With different rates of biochar application, the reduction of dissolved Zn concentrations in the sediment pore water ranged from 11.7% to 62.8%. BCR sequential extraction showed that heavy metals in the sediments tended to transform from acid-soluble fraction to residual fraction. Acid-soluble fraction of Cu decreased by 73.08 mg. kg^-l（32.1%） at the biochar application rate of 5%, while oxidizable fraction of Pb increased by 67.8%. Physiologically based extraction test showed that, when 5% biochar was applied, bioavailable Cu was reduced by 9.8% with simultaneous decrease in bioavailable Zn, Pb and Cd. When the phytotoxicity test was carried out with sediments remediated by biochar, the stem length of Lepidium sativum significantly increased by 19.5% to 25.7%, and the root length increased as well. The result biochar application could reduce the phototoxicity of heavy metals in the sediments. suggested thatbiochar application could reduce the phototoxicity of heavy metals in the sediments.