§ Captain Kerbyasked the Minister of Agriculture, Fisheries and Food what precautions are being taken to ensure against primary poisoning to fish and secondary poisoning to man in the disposal of chemical residues in contaminated soil and sludge at sea.
§ Mr. SoamesI am advised that fluoroacetamide, while stable, is extremely soluble in water, and that the dumping of the soil and sludge from Smarden beyond the continental shelf would obviate any risk.
§ Captain Kerbyasked the Minister of Agriculture, Fisheries and Food, in view of the fact that the manufacturers of Tritox, used at the rate of 10 parts per million of fluoroacetamide, advised against using their product on edible plants, why his department advised the use of Megatox at the strength of 250 parts per million on edible crops such as sugar beet, brassicas, broad beans and strawberries; and what tests were carried out before the time interval of four weeks between spraying and harvesting was advised, in view of the fact that fluoroacetamide is now known to remain stable in soil and water for a number of years.
§ Mr. SoamesOn the recommendations of the Advisory Committee on Poisonous Substances used in Agriculture and Food Storage, the Government Departments concerned agreed to the use of Magatox on four out of the seven edible crops requested by the manufacturers, subject to recommendations for its safe use which stipulated the maximum rate and frequency of application for each crop and laid down a minimum interval of four weeks between spraying and harvest. These recommendations were based on the results of a series of studies carried out by the manufacturers, a consultant research centre and my Department which showed that the amount of fluoroacetamide in the crops four weeks after spraying was nil or barely detectable. While fluoroacetamide is very stable in pure water, in soil it is broken down by micro-organisms and soon loses its activity.