Mercury levels in wheat and other cereals, oilseed and biological samples

Abstract

Abstract Analyses of 80 samples of wheat showed a mean mercury content of 8 ng/g, with a range of 4 to 18 ng/g (ng = 10 −9 g). Wheat flour contained the same amount of mercury as wheat. Other cereals and oilseeds contained 4 to 29 ng/g of mercury. Levels of mercury varied for other organic materials analysed. The analytical method used is relatively rapid and simple when certain precautions are followed. The method consists of an oxygen‐bomb combustion of samples, reduction of the mercury in the bomb washings to elemental mercury and then analysis of the mercury by cold vapour atomic absorption spectrophotometry. The limit of detection of the method is approximately 1 to 2 ng of mercury/g of sample. The reliability of the method was verified by quantitative recoveries of added organic and inorganic mercury compounds from wheat and barley and by carrying out collaborative tests.