石灰修复重金属污染土壤及其对水稻效应

[目的]探讨石灰对实际污染土壤的修复效果,为重金属污染土壤的治理提供科学依据。[方法]研究不同浓度石灰水溶液(0.025%和0.050%)淋洗受铅锌矿尾矿严重污染的水稻土对水稻的影响。[结果]石灰水溶液可以将土壤中的Cu、Zn和Pb等重金属淋洗出来,淋洗次数越多,土壤中重金属含量越低。土壤中Pb的含量降幅最大,其次是Zn,最低为Cu。低浓度石灰溶液(0.025%)淋洗6次以上、高浓度(0.05%)淋洗5次以上对去除土壤中的Pb、Cu、Zn重金属效果明显。水稻能在经石灰淋洗过的土壤上生长,发芽率和生物量随着淋洗次数的增多而增加,但石灰水溶液浓度过高或淋洗次数过多则降低水稻发芽率和生物量,还导致植株Pb含量升高。[结论]利用石灰修复铅锌尾矿污染的农田土壤是可行的,但石灰用量要适当。

Remedying Soil Contaminated by Heavy Metal with Lime and Its Effect on Rice

[Objective] The research aimed to discuss the remediation effect of lime on practically polluted soil so as to provide scientific basis for the control of soil contaminated by heavy metal.[Method] The effect of paddy soil severely contaminated by lead-zinc tailings and leached by lime aqueous solution with different concentrations(0.025% and 0.050%) on rice was studied.[Result] Heavy metals of Cu,Zn and Pb etc.in soil could be leached out with lime aqueous solution and the more the leaching times,the lower the heavy metal content in soil was.The decrement of Pb content in soil was biggest,that of Zn was secondary and that of Cu was lowest.The effects of eliminating heavy metals of Pb,Zn and Cu in soil by leaching with low concentration lime aqueous solution(0.025%) for more than 6 times or with high concentration lime aqueous solution(0.05%) for more than 5 times were obvious.Rice could grew on the soil leached with lime aqueous solution and the germination rate and biomass increased along with the increment of leaching times,but the lime aqueous solution with too high concentration or leaching for too many times would reduce rice germination rate and biomass and cause Pb content in plant to increase.[Conclusion] Using lime to remedy farmland soil contaminated by lead-zinc tailings was feasible,but the lime dosage should be suitable.