HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Elliott, H. A. Articles by Linn, J. H. Search for Related Content PubMed Articles by Elliott, H. A. Articles by Linn, J. H. Agricola Articles by Elliott, H. A. Articles by Linn, J. H.

Effect of Calcium Magnesium Acetate on Heavy Metal Mobility in Soils¹

ABSTRACT

Calcium magnesium acetate (CMA) is a promising replacement for traditional roadway deicing salts. Prepared in a 3:7 Ca/Mg molar ratio, CMA was studied to assess its impact on the mobility of metals in contaminated soils. In batch soil suspensions (pH 3–7), 0.01 and 0.1 M CMA solutions substantially enhanced Zn and Cu desorption from a metal-enriched soil. In soil columns leached with acidified (pH 4) 0.01 M CaCl₂, a thin layer of CMA initially increased metal efflux. Preferential adsorption of Ca²⁺ and Mg²⁺ at exchange sites (i) displaced bound metal ions into solution and (ii) desorbed H⁺, which promoted dissolution of metal-containing solid phases. This was counteracted by the pH neutralizing effect of acetate ions, so that within 10 pore volume displacements, the presence of CMA resulted in a net suppression of leachate metal levels. In pH-controlled batch experiments, metal solubilization was not significantly different between equimolar amounts of CMA and the Cl^– or NO^–₃ salts. Thus, under the experimental conditions, acetate complexation played a minor role in metal mobilization. Highway deicing with CMA may temporarily increase translocation of metals in strongly buffered acid roadside soils. Input of acetate ions and an increase in exchangeable bases with sustained CMA use should render northeastern USA soils less vulnerable to acidification, thereby inhibiting conditions that promote metal solubilization.

Key Words: solubilization • complexation • highway deicing • adsorption

¹ This work was part of Regional Research Project NE-96: Soil Properties Affecting Sorption of Heavy Metals. Approved as Journal Series no. 7518 of the Pennsylvania Agric. Exp. Stn.

² Associate Professor and Research Assistant, respectively, Agricultural Engineering Dep., Pennsylvania State Univ., University Park, PA 16802.

Received for publication October 24, 1986.