Fate of Ionic Thiocyanate (SCN−) in Soil

Abstract

Ionic thiocyanate (SCN−) additions to soil result from anthropogenic and natural sources; however, little is known concerning the fate of this anion in soil. Six soils were amended with SCN− at concentrations expected from Brassica tissues. Thiocyanate in 0.005 M CaCl2 extracts was quantified using ion chromatography. The decrease in SCN− concentrations with time for incubations conducted at or below 30 °C was positively correlated with soil organic carbon content in five of six soils. Autoclaving soils prior to incubation and adding NaN3 or allyl isothiocyanate slowed SCN− disappearance. Waterlogged conditions slowed disappearance initially, but the trend was not observed at 72 h. Extract concentrations of SCN− also decreased when the soils were incubated at higher temperatures of 50 or 60 °C. Microbial degradation of SCN− is the main factor responsible for SCN− disappearance at or below 30 °C. At higher temperatures decreases in extractable SCN− involve sorption or degradation by abiotic catalysis. © 1993, American Chemical Society. All rights reserved.