§ Mr. DalyellTo ask the Secretary of State for the Environment what study he is making of the problems of leakage of polychlorinated biphenyls from hydraulic irrigation made available to him by Dr. Chris Mason of the Department of Biology in the university of Essex, and consequent dangers to others.
§ Mr. Heathcoat-AmoryNeither I, nor my right hon. Friend the Minister of Agriculture, Fisheries and Food, have any record of receiving copies of a report from Dr. Mason on the problems of leakage of polychlorinated biphenyls (PCBs) from hydraulic irrigation pumps.
My officials have written to Dr. Mason to obtain a copy of the report and when I have studied it, I shall write to the hon. Member.
§ Mr. DalyellTo ask the Secretary of State for the Environment what research is available to him on the concentration of polychlorinated biphenyls in large oily fish favoured by marine mammals.
§ Mr. Heathcoat-AmoryMarine mammals show considerable variation in their feeding patterns and movements as illustrated in research on seals monitored around the Isle of May in the Firth of Forth and commissioned by my Department from the Natural Environment Research Council's sea mammal research unit. In some localities, marine mammals show a preference for oily fish such as herring, mackerel and sandeel.
As part of their general monitoring programme of commercial 'species consumed by humans, both the Ministry of Agriculture, Fisheries and Food, and in Scotland, the Department of Agriculture and Fisheries monitor PCB levels in herring and mackerel. These show generally that concentrations of lipophilic contaminants such as PCBs are higher in the tissues of oily fish than in other fish with a lower natural lipid content, but not so high in edible tissues as to affect human health. As yet no comparable data are available for sandeels, but DAFS is currently considering new work on the food chains of marine mammals and this will address in particular the bio-accumulation of persistent organochlorines such as PCBs.