淹水对污染土壤镉形态转化的影响

研究了受铜冶炼厂“三废”污染的土壤在栽种小麦－水稻－小麦的过程中土壤镉形态的转化。结果表明，淹水后交换态镉形态所占比例明显下降，下降幅旗与土壤氧化铁活化度呈极显负相关。所下降的部分向着活性较低的紧结合有机态，晶形氧化铁结合态及石灰性土壤的碳酸盐结合态转化。

EFFECTS OF FLOODING ON THE TRANSFORMATION OF CADMIUM FRACTIONS IN CONTAMINATED SOILS

The transformatoin of cadmium fractions in soils contaminated by a copper smelter dur-ing the period of wheat-rice-wheat rotation was studied. The results showed that:1)Dry-ing of soil samples collected during the rice growth season had a significant effect on the dis-tribution of cadmium fractions, thus the fractionation of soil samples under flooded conditionmust be carried out in fresh state without drying;2) The amount of exchangeable cadmiumdecreased significantly and rapidly and transformed into fractions strongly bound to organicmatter,to crystalline iron oxide and to carbonate in calcareous soil after the soil was flooded;3) After the flooded soil was redried, the distriubtion of cadmium fractions was nearly asthe same as that before flooded, except of the fraction of cadmium strongly bound to organicmatter in former one was slightly higher than that in latter one,that is,flooding enhancedthe affinity of organic matter to bound cadmium.