重金属污染土壤修复及其对作物效应

The Remediation of Heavy Metals Polluted Soil by Washing with Chemicals and its Effects on Crops

为了探讨不同的淋洗剂修复重金属污染的土壤效果,笔者研究利用水、石灰水、EDTA溶液、水+石灰水(即先用水淋洗后,再用石灰水淋洗)、水+石灰水+EDTA溶液(即先用水淋洗后,再用石灰水淋洗,最后用EDTA溶液淋洗)等5种淋洗方法处理尾矿重金属严重污染的土壤。结果表明:水、石灰水以及EDTA溶液等均能提取污染土壤中的重金属,其中EDTA提取的能力最强,水其次,而石灰水最弱;水稻、玉米、大豆和南瓜等4种作物在不经过修复的污染土壤上不能正常发芽生长,而在修复后的土壤上都能正常发芽,但水处理和EDTA溶液处理的土壤,种子发芽后很快死亡,而其他处理的作物仍可继续生长;石灰水或水+石灰水处理的土壤,作物生物量较高;在污染土壤上生长的作物均能吸收重金属,其中大豆和水稻吸收能力较强。这些结果表明,可以利用石灰来修复重金属尾矿污染的土壤,在修复的土壤上生长的大豆和水稻重金属含量较高,在作物布局上要尽量避免种植这2种作物。

In order to research the effects of remedying heavy metal polluted soil with washing chemicals,the heavy metal polluted soil,on where plants were not able to grow,was remedied by chemical washing.The washing chemicals of water,lime solution and EDTA solution were used single or combinational to sequential wash soil.Four crops of rice,soybean,corn and pumpkin were planted on treated soil in order to assess effects of chemical.The results indicated that water,lime solution and EDTA solution could extract heavy metals from soil,but their ability were different,with EDTA solutionwaterlime solution.The four crops were able to germinate on treated soils,but all crops were all phytotoxic and died after germination on the soil washed by water or EDTA solution.The biomass of plants grown on the soils washed by lime solution or water ＋lime solution was higher than that of other treatments.All crops accumulated more heavy metals from remedied soils than that from normal soil,but the accumulating ability of soybean and rice to heavy metals was higher than corn and pumpkin.The conclusion was that lime was able to reduce toxicity and was a good amender for remedying the polluted soil by heavy metals;the accumulating abilities to heavy metals of soybean and rice were higher than that of corn and pumpkin.