§ Mr. Teddy Taylorasked the Secretary of State for the Environment what evidence is available about alterations in the level of nitrates in public water supplies since 1960; and if he will make a statement.
§ Mr. Giles ShawThe nitrate level in an individual public water supply varies according to the season and climate. If the source is derived from surface water these variations can be extreme with the variation from summer to winter more than an order of magnitude greater than that from year to year; in general the nitrate levels have not reached the heights they attained in the period following the 1976 drought. However, the underlying trend of both mean and maximum values has been upward, since 1960 in some areas, and rather later in others. Water authorities, health authorities and the Government are aware of the problems and have measures available to combat it.
§ Mr. Teddy Taylorasked the Secretary of State for the Environment what levels of nitrates exist in the public water supplies in Essex and in Southend-on-Sea; and what is the average for water supplies in England.
§ Mr. Giles ShawSouthend-on-Sea is supplied from two sources—Hanningfield and Langford—which mix in varying degrees in the distribution system. The current nitrate contents are 18 and 53mg/1 respectively, the averages for 1982 were 15 and 46mg/1. The public water supplies in the remainder of Essex vary widely in nitrate content but contain less than 50mg/1. The nitrate content of public water supplies in the rest of England also vary widely with source season and climate but for over 90 per cent. of those supplied remains below 50mg/1 all the year round. Environmental health officers and medical practitioners are notified should this level be exceeded. An average nitrate level for England is neither meaningful nor available.