Extractable Metals, 1 M HNO3

Metals are extracted by shaking 3 g of air dried soil in 30 mL of 1 N HNO3for 1 hour. After centrifugation, the supernatant analyzed for Al, Cd, Cr , Cu, Fe, Mn, Ni, Pb, and Zn by ICP-AES.

(See Method References No. 32 & 21)