Nitrate and water supplies in the United Kingdom

Abstract

Nitrate concentrations in UK waters are rising, with the highest levels occurring in the south and east of England, particularly Lincolnshire, Cambridgeshire and East Anglia. The source of the nitrate is arable agriculture where intensification in the last few decades has increased nitrate leaching from soils into both surface and underground waters. Concentrations in underground waters are expected to reach 150 to 200 mg litre −1 nitrate (i.e. NO 3) in the future, if agricultural losses remain stable. No widespread environmental deterioration due to nitrate has been observed in rivers or lakes. Excessive concentrations of nitrate in drinking waters can cause methaemoglobinaemia (blue-baby syndrome) in bottle-fed infants and the government Chief Medical Officer has recommended that a maximum concentration of 100 mg litre −1 is appropriate for public water supplies in the UK. This level has not been exceeded in public water supplies in the UK, but maintaining it has cost approximately £15m in borehole replacement and arrangements to blend high and low nitrate waters. Future capital costs are estimated as £37m over the next 20 years. The European Economic Community (EEC) Drinking Water Directive (80/778/EEC) sets a maximum admissible concentration of 50 mg litre −1 nitrate. Adherence to this standard will cost £199m over the same period.