蚯蚓对土壤中铜、镉生物有效性的影响

以第四纪红黏土红壤和长江冲积物形成的高砂土为供试土壤、分别加入3个浓度的Cu^2 (100、200、400mg／kg)或Cd^2-(5.10、20mg/kg)模拟土壤污染．设置接种蚯蚓(Pheretima sp.)处理与不加蚯蚓对照．并种植黑麦草(Lolium multiflorum)、研究蚯蚓活动对土壤中Cu、Cd生物有效性的影响．以揭示蚯蚓在植物修复重金属污染土壤中的作用。结果表明：蚯蚓活动显著增加红黏中DTPA提取态Cu的含量、只有在浓度低于200mg／kgCu的处理中．才能增加CaCl2提取态Cu的含量．对H2O提取态Cu影响甚微；而对高砂土上Cu、Cd的各种形态影响均不显著；除红黏中浓度高于100mg／kgCu和10mg／kgCd处理外．蚯蚓活动显著提高了两种土壤上黑麦草地上部的生物量；接种蚯蚓后各种重金属处理中黑麦草对Cu的吸收量也显著增加，而Cd的吸收量变化不大。蚯蚓可能通过提高重金属的生物有效性而间接影响植物对重金属的修复效率。

Effect of earthworm on bio-availability of Cu and Cd in soils

Phytoremediation of heavy metals in contaminated soil has been widely accepted as a cost-effective, environmental-friendly technology. Metal-accumulating plants are usually planted to remove metals from soils by concentrating them in the harvestable parts, while the efficiency depends on the amount of aboveground biomass and the bioavailabililty of metals. Though addition of chelating agents has been shown to increase metal bioavailabililty and phytoremediation efficiency, it costs too much and shows enviro...