HC Deb 30 January 1963 vol 670 cc195-6W
Captain Kerby

asked the Minister of Agriculture, Fisheries and Food whether his scientific advisers are satisfied that rodent control at ports is more effectively carried out by the use of sodium fluoroacetate than by fumigation; how this poison is administered; what quantities are used; and what steps are taken to prevent the contamination of foods and beverages intended for human consumption.

Mr. Scott-Hopkins

Sodium fluoroacetate baits and fumigation are not simple alternatives. At the ports, the method used depends on the circumstances. On ships, where either method is possible, there has been a trend towards baits, because they are cheaper and present less risk to man.

As a rodenticide, sodium fluoroacetate is usually used in liquid form at a dilution of 1 in 400. Information on total quantities used is not available.

The sale and distribution of sodium fluoroacetate in England, Wales and Scotland is restricted by the Poisons Rules, which require purchasers to have an authority certificate signed by a Medical Officer of Health or by certain officers of one of the Agricultural Departments. The poison must be coloured and stored under lock and key. All containers must be labelled "Poison". Detailed precautions designed to prevent any possibility of contamination, are set out in a Ministry leaflet entitled "Use of Sodium Fluoroacetate as a Rodenticide".

Captain Kerby

asked the Minister of Agriculture, Fisheries and Food what is the minimum dosage of fluoroacetamide or sodium fluoroacetate recommended by his scientific advisers for the destruction of rats in sewers; whether vegetation growth on this public effluent after treatment contains fluoride in any form; what advice he has received on the cumulative danger of this chemical to browsing sheep and cattle; and, in those cases where the effluent finds it way into rivers or the sea, what effect fluoride in any form has on fish.

Mr. Scott-Hopkins

The recommended concentrations of sodium fluoroacetate and fluoroacetamide for use as rodenticides are one part in 400 and one part in 50 respectively.

The maximum resulting concentration of fluoride in vegetation is infinitesimally small and presents no cumulative danger to cattle or sheep. Such concentrations are very much less than those sometimes occurring naturally in soils and also very much less that the smallest concentration of fluorides known to be toxic to fish.