Estimating total Pb, Cd, and Zn in contaminated soils from NH₄HCO₃‐DTPA‐extractable levels

Twenty‐six garden soils from Aspen, Colorado, contaminated with old silver mine dumps, were extracted with diethylenetriamine pentaacetic acid (DTPA) and NH4HCO3‐DTPA (AB‐DTPA). Total soil digests (HNO3‐HClO4‐HF) were carried out on 21 highly contaminated soils. All soil extracts and digests were analyzed for Pb, Cd, and Zn using inductively‐coupled plasma atomic emission spectrometry (ICPS). Linear regression equations for DTPA versus AB‐DTPA values gave 0.96, 0.99 and 0.99 “r”; values for Pb, Cd, and Zn, respectively. Linear regression equations for total Pb, Cd, and Zn levels versus their respective AB‐DTPA extractable levels were developed with “r”; values of 0.92, 0.93, and 0.89, respectively. It was concluded that AB‐DTPA test can be used to screen soils contaminated with the above‐mentioned elements.