Determination of total mercury in sediments and soils

Abstract

A highly sensitive and precise procedure has been developed for the quantitative determination of total mercury in sediments and soils. Undried samples are treated with concentrated nitric and sulphuric acids, potassium permanganate and potassium persulphate in order to digest and oxidise all forms of mercury to mercury (II) ions, which are subsequently determined by flameless atomic-absorption spectrophotometry. Recovery of mercury, added as mercury(II) chloride, methylmercury chloride, phenylmercury hydroxide or phenylmercury acetate to a lake sediment, ranged from 98 to 105 per cent. The procedure developed by us resulted in the extraction of more mercury from sediments and soils than did extraction with concentrated nitric acid. Drying at 60 °C caused a significant loss of organomercury compounds from a lake sediment.