模拟酸雨下土壤中铜、镉行为及急性毒性效应

本文论述模拟酸雨下红壤、黄棕壤和黑土中Cu、Cd行为及急性毒性效应.试验表明:(1)模拟酸雨对添加性土壤Cu、Cd的淋溶有一定的影响,随着降水酸度的增大,土壤中Cu、Cd的淋出量增加,但增加的程度与土壤类型、添加金属的浓度和种类有关,相同酸度下,红壤中Cu、Cd的淋出量远大于黄棕壤和黑土,淋出率随着沉降酸度而改变的程度也最显著,酸雨对黑土中Cu、Cd淋溶影响最小.Cd对酸雨淋溶的敏感性大于Cu.(2)模拟酸雨对土壤中Cu、Cd形态影响较为明显,随着酸雨pH的降低,黄棕壤和黑土中部分Cu、Cd形态明显地向着交换态转化,红壤中部分Cu、Cd形态明显地向着水溶态转化.(3)模拟酸雨对土壤中Cu、Cd的生物毒性影响很大,但这种影响同时又受土壤类型相当大的制约,红壤中毒性影响最大,黑土中毒性影响最小,表明三类土壤的抗酸能力顺序为黑土>黄棕壤>红壤.

The Effects of Simulated Acid Rain on the Be-havior of Cu and Cd in Soils and Their Acute Toxicity

The basic emphasis of this work is to research the behavior of Cu and Cd in red soil, yellow brown soil and black soil and their acute toxichy under simulated acid rain conditions. The experimental results were as follows: (1) The simulated acid rain had some influence upon lca-ching of Cu and Cd in soil. As the acidity of precipitation was increased, Cu- or Cd-leaching amounts were increasing. However, the increased level differed from variant soil and concentrations of the metals added to soil. Under the condition of same acidity, Cu or Cd amounts leached from red soil were much larger than those from yellow brown soil or black soil. Leaching of Cd was more sensitive than that of Cu.(2) The effects of simulated acid rain on speciations of Cu or Cd in soils were relatively obvious. With ,pH values of the precipitation reducing, a partial Cu and Cd in yellow brown soil and black soil were transformed into exchangeable speciation, and those in red soil transformed into water-soluble form.(3) Acid rain evidently affected biotoxicity of Cu or Cd in soil. The effect of Cu- or Cd-biotoxicity was high in red soil and low in black soil.In short,the acid resistant capacity of soils in order is black soil > yellow brown soil > red soil.