Dissolving Heavy-Metals From Soils With Acids In Order To Approximate Total Element Content

The average percentages of copper, zinc and nickel extracted with 2 N HNO 3 from typical slightly contaminated Swiss soils resulted in 59, 68 and 58% of the total, respectively. The amounts rose to 85% for zinc and to 69% for nickel using 3 N HCl. Copper, however, showed no higher solubility in this solvent. Possible reasons for the different solubility patterns of heavy metals are discussed on the basis of results obtained from X‐ray and infrared investigations of soil colloids.