菜地土壤镉的表层淋洗-深层固化联合修复研究

Remediation of cadmium contaminated vegetable field via surface leaching-deep solidification combined technology

为探究表层淋洗-深层固化联合修复技术对重庆郊区菜地土壤及蔬菜镉(Cd)污染的修复效果,采用大田试验,研究了酒石酸表层淋洗-HAP深层固化和水表层淋洗-HAP深层固化处理对莴笋产量、品质及Cd的吸收和土壤全Cd及有效Cd含量的影响,并与传统修复剂腐植酸和HAP进行比较。结果表明,酒石酸淋洗-HAP固化使莴笋茎叶中的Cd含量显著降低22.89%、莴笋产量显著提高16.89%,且对莴笋的品质有促进作用。同时,酒石酸淋洗-HAP固化处理使0~20cm表层土壤的全Cd含量降低30.71%,40~60cm深层土壤的全Cd含量增加51.57%,在两种表层淋洗-深层固化处理下,土壤中有效Cd含量均在0~20cm土层减少,20~40cm土层略微增加,40~60cm土层明显降低,在60~80cm土层与对照接近。莴笋茎叶和根部的Cd含量与土壤有效Cd呈显著正相关,与土壤有机质呈显著负相关。表层淋洗-深层固化联合修复能够在进行土壤Cd污染修复的同时实现蔬菜的安全生产,适宜向轻度污染的蔬菜基地推广使用。

In order to study the effect of surface leaching-deep solidification combined technology on the remediation of cadmium-polluted soil and cadmium content in vegetables in Chongqing suburbs,field experiments were conducted to investigate the effects of tartaric acid surface leaching-hydroxyapatite(HAP)deep solidification and water surface leaching-HAP deep solidification treatments on lettuce yield,quality,cadmium uptake,soil total cadmium,and available cadmium content.The results were compared with those of treatment by tradi⁃tional repair agents such as humic acid and HAP.The final results showed that talc acid leaching-HAP solidification could significantly re⁃duce the cadmium content in lettuce stems and leaves by 22.89%;furthermore,the lettuce yield significantly increases by 16.89%accom⁃panied with the quality promotion.Meanwhile,the total cadmium content of the surface soil of 0~20 cm was reduced by 30.71%,while the total cadmium content of the deep soil of 40~60 cm increased by 51.57%.Under these two kinds of surface leaching-deep solidification treatments,the available cadmium content in soil at depths of 0~20 cm decreased,then slightly increased at depths of 20~40 cm,followed by a significant decline in the 40~60 cm soil layer.When the soil depth reaches 60~80 cm,the available cadmium content was closer in value to the control group.The cadmium content in the stems,leaves,and roots of the lettuce showed a positive correlation with the soil available cadmium,while it was negatively correlated with the soil organic matter.Surface leaching-deep solidification combined remediation can,therefore,realize the safe production of vegetables while remediating cadmium polluted soil,which is suitable for production and remediation at lightly polluted vegetable bases.