§ Mr. Pardoeasked the Secretary of State for Education and Science (1) what was the average concentration of polychlorinated biphenyls found by the National Environmental Research Council in the livers and blubber of seals found dead around the Cornish coast in 1970; 298W how this differed from the levels found in North and East Anglia; what is her Department's estimate of a lethal concentration in seals; and what estimate she has made of the source of this pollution;
(2) what were the average concentrations of mercury found by the National Environmental Research Council in the livers and blubber of seals found dead around the Cornish coast, the northern coasts, and the East Anglian coast in 1971; what is her estimate of a lethal concentration in seals; and what estimate she has made of the sources of this pollution.
§ Mrs. ThatcherSeals found dead on the Cornish coast at the end of 1969 were analysed for polychlorinated biphenyls and mercury. The results from these and comparable samples from other parts of England are given in Natural Environment Research Council publications Series C: No. 1: 1970. I am sending a copy to the hon. Member and another has been placed in the Library.
The data so far obtained are not sufficient to indicate what level of contamination might be lethal to the animals. Material from seals is still being collected and further analyses are being made. The report concludes that the deaths were attributable to natural causes and particular sources of pollution are not known to be involved.