§ Mr. HoodTo ask the Secretary of State for the Environment what information he has as to the mean annual nitrate concentration in the River Thames, at Walton, since 1975.
§ Mr. MoynihanThe mean annual concentrations of total oxidised nitrogen in the river Thames at Walton are as follows:
Milligram per litre as NO Year 1975 26.8 1976 33.2 1977 34.2 1978 31.5 1979 33.2 1980 28.8 1981 31.1 1982 30.0 1983 29.7 1984 31.3 1985 34.4 1986 30.2 1987 30.0 1 1988 30.0 1 January to September.
§ Mr. HoodTo ask the Secretary of State for the Environment what steps his Department takes to ensure that the lowest possible methanol residual in denitrified water, is achieved; and if he will make a statement.
§ Mr. MoynihanDenitrification processes which use methanol are still at an experimental stage. One of the aims of these experiments, which are being partly funded by the Department, is to limit methanol residual in the denitrified water.