不同类型固化材料对Cu污染水稻土的修复效果差异

Effects of four types immobilizers on Cu immobilization in contaminated paddy soil

通过室内实验,比较有机肥、钙镁磷肥、海泡石和石灰石等4种固化剂对铜污染土壤的pH和铜赋存形态的影响,从而筛选出最优的固化剂及其添加量.实验结果表明,添加钙镁磷肥、有机肥与石灰石均能显著提高土壤pH值,提高幅度依次为石灰石>钙镁磷肥>有机肥,海泡石对土壤pH值几乎无影响.依据作物生长最适pH值,石灰石和钙镁磷肥的添加量分别控制在4 g·kg^(-1)、8 g·kg^(-1)以下为宜;钙镁磷肥、有机肥和石灰石对土壤中Cu赋存形态的影响均表现出可交换态比例下降,有机结合态比例升高;3种固化剂的固化效果为:4 g·kg^(-1)石灰石>8 g·kg^(-1)钙镁磷肥≈8 g·kg^(-1)有机肥,而海泡石的固化效果较差,不宜用于改良该Cu污染的土壤.

As an effective measure for remediation of heavy metal contaminated soil,heavy metal immobilization can ease the contradiction between pollution and safety of agricultural products in a certain degree. Organic fertilizer（ OF）,calcium magnesium phosphate fertilizer（ CMPF）,sepiolite（ SP） and limestone（ LS） are common heavy metal immobilizers. In laboratory with pot experiments,their remediation efficiency in Cu contaminated paddy soil was investigated,in order to screen out the best one and the suitable dosage of the four immobilizers. The results showed that CMPF,OF and LS significantly increased soil pH,with the order of LS,CMPF and OF,SP had no effect. From the perspective of the optimal pH adjusting crop growth,the additive level of LS and CMPF were not exceeding 4 g·kg^（-1）,8 g·kg^（-1）,respectively. CMPF,OF and LS decreased exchangeable Cu content,and increased organically bonded state. The order of the solidification effect was 4 g·kg^（-1）LS 8 g·kg^（-1）CMPF≈ 8 g·kg^（-1）OF. SP was worst of all,and is not suitable for remediating the Cu contaminated paddy soil.