Determination of mercury in soil

Abstract

An analytical procedure for the determination of mercury in soil is described. After the digestion of organic matter, the mercury is removed from the soil by distillation in hydrochloric acid gas, extracted from the distillate with dithizone and measured spectrophotometrically. IntroductionAn earlier report1 described a method for the determination of mercury in plant material. In work on the uptake of mercury by plants2? a method was required for the determination of mercury in soil. Stock and his c o -w o r k e r~~-~ heated powdered minerals at 800' for several hours, and the 'volatilised mercury was collected and electrolytically deposited on copper, from which it was distilled to condense as droplets whose sizes were measured. Substances such as coal which gave interfering distillates were wet-digested to bring the mercury into solution. Arable and forest soils showed 0.01-0.3 p.p.m. and compost from gardens contained 0.8 p.p.m. of Hg. Stock' also used the electrolytic deposition procedure to examine soils and other materials ; soils showed 0.03-0.3 p.p.m., coal 0,02 p.p.m., street dust 0.9 p.p.m. and soot up to 28 p.p.m. Hg.