§ Mr. BradyTo ask the Secretary of State for Environment, Food and Rural Affairs what recent estimate she has made of the percentage of nitrate pollution in rivers which arises from discharges by sewage treatment plants. [48076]
§ Mr. MeacherThe Environment Agency's 2001 publication "Rivers and Estuaries—a decade of improvement" provides information on general trends in nitrate levels of rivers in England and Wales. Although this information does not identify the source of the nitrates, the Agency's assessment was that in 2000 some 32 per cent. of rivers had high average concentrations of nitrate (greater than 30mg/1), and about 50 per cent. moderate or high average concentrations (greater than 20mg/1). It is considered that the average nitrate contribution from sewage treatment works is likely to be less than 20 per cent., and in most cases less than 10 per cent. However, where relatively large works, such as Altrincham and Sale, discharge to small rivers and provide a significant proportion of their flow, the nitrate contribution is likely to be higher than 20 per cent. immediately downstream of the discharge.
Where surface freshwaters are used for the abstraction of drinking water the Environment Agency has on-going monitoring at numerous points. If sampling confirms the presence, or likelihood, of more than the permitted concentration of nitrates, and the source of the nitrates is sewage treatment works, then we identify the stretch of river as a Sensitive Area (Nitrate) under the Urban Waste Water Treatment Regulations, and reduce the amount of nitrates in the discharge from qualifying works.
On 5 March 2002 I announced the identification of stretches of the rivers Chelmer, Leam, Stour and Wissey as Sensitive Areas (Nitrate), and the requirement for two water companies to reduce the nitrate in discharges from six sewage treatment works by 2004.