Tartrate retention by a typic haplustoll

Abstract

Tartaric acid is a low‐molecular weight organic acid commonly present in the soil solutions of humic horizons. Tartrate anion forms relatively stable complexes with heavy metals, which may affect heavy metal mobility in the root zone and uptake by plants. However, no methods are available for determining its content in soils and there are no data on behavior of tartrate anion in soil media. This study was conducted to develop a technique to determine tartrate anion content in soils and to evaluate its retention by the silty clay Typic Haplustoll. The results indicated that tartrate anion interaction with soil consists of a fast stage of adsorption and calcium tartrate precipitation (about 2 hours), followed by a microbial degradation after a lag‐period of 30–40 hours. Tartrate anion retention reached a maximum at a pH from 4.2 to 4.5. Retained tartrate anion was effectively extracted from the soil by successive treatments with water and 0.1M HCl, and quantitatively determined by ion chromatography. The relation between added (Ga) and recovered (Gr) tartrate anion amounts in the range from 2.6 to 40 mmol kg‐1 was expressed by the equation Gr=0.991*(Ga‐1.1), where Gr and Ga are in mmol kg‐1 soil. The standard deviation of the recovered amount of tartrate anion was 1.5 mmol kg‐1 soil. The retention isotherms can be fitted by the Freundlich equation.