Use and residues of mercury compounds in agriculture

Mercury compounds were first used in Germany as seed dressings to control seed-borne diseases of cereals about 1914. ‘Uspulun’, described as a ‘chlorophenolmercury’ compound was placed on the market in 1915 by Bayer A.G. as a liquid dressing and was soon widely used. Dusts, such as ‘Ceresan’, at first having phenylmercury acetate as the active ingredient and, subsequently, a methoxyethylmercury compound, and ‘Agrosan’, a tolylmercury acetate formulation, became more widely used ten years later. Liquid treatments, using alkylmercury active ingredients, were reintroduced about the time of World War II because of the reduced hazards and inconvenience to operators dressing the grain in specially designed machines, although alkylmercury compounds are more toxic than arylmercurials. In Sweden it has recently been found that the extensive use of alkylmercury compounds can lead to harmful contamination of the environment and there they have been replaced by other organomercury compounds. In most countries both liquid and dust treatments are commonly used. Formulations containing organo- mercurials have been found to give a better control of fungal diseases of grain than non-mercurial formulations.