§ Mr. Greville Jannerasked the Secretary of State for the Environment what percentage of British canals and waterways is subjected to environmental pollution.
§ Mr. Eldon GriffithsThe River Pollution Survey of England and Wales does not distinguish navigable waterways from other rivers. The survey updated to 1972, published last year, shows that the water was grossly polluted in 5.1 per cent. of the length of canals; of poor quality in 9.5 per cent.; and of doubtful quality in 39.7 per cent. The proportions for non-tidal rivers were respectively 3.7, 4.2 and 14.7 per cent.; and for tidal rivers 13.2, 14.2 and 23.2 per cent.