HC Deb 22 February 1977 vol 926 cc533-4W
Mr. Skeet

asked the Secretary of State for the Environment why Bedford has more nitrate in its drinking water than other areas in the United Kingdom although nitrate fertilisers are used generally all over Great Britain.

Mr. Marks

Leaching of artificial fertilisers is only one source of nitrate. Other sources are bacteriological action in the soil and sewage effluent in the rivers. The concentration of nitrates is also dependent on intensity and distribution of rainfall, land usage patterns and the geology of the catchments. There are in fact other areas in the United Kingdom which have more nitrate in their water supplies than does Bedford.

Mr. Skeet

asked the Secretary of State for the Environment if the concentration of nitrates in water should exceed an accepted safety level, what action is open to the appropriate authority in the public interest to neutralise its injurious effects.

Mr. Marks

Water authorities in the United Kingdom usually follow the World Health Organisation's European Standards for Drinking Water. If the nitrate level in a water authority's intake exceeds the acceptable level, then the nitrate concentration is reduced by blending with water of low nitrate content. Where water supplies are known to be liable to high nitrate levels, medical officers and practitioners have been alerted and contingency plans have been prepared to supply low nitrate content water for infant feeding should the nitrate level rise to a level where this is deemed desirable.

Mr. Skeet

asked the Secretary of State for the Environment what is the effect of nitrates in water on various age groups in humans and its biological impact.

Mr. Marks

The only known effect of nitrates in water on humans is that a small number of cases of cyanosis in babies under six months old have been associated with high nitrate levels in the water used for preparing their feeds. The condition is reversible if the infant's feeds are subsequently made with low nitrate water. No cases were reported during the recent drought.