§ Mr. ToddTo ask the Secretary of State for Environment, Food and Rural Affairs if she will publish the scientific advice she has received concerning the designation of nitrate vulnerable zones; and if she will make a statement. [28506]
§ Mr. MeacherThe Environment Agency has provided science-based advice on the methodology used to identify areas for designation. This is included as an annex in the consultation document "How should England implement the 1991 Nitrates Directive" published on 20 December 2001.
Nitrate vulnerable zones comprise land designated because it drains into nitrate polluted waters, or waters that could become nitrate polluted. Three methods are used to identify such waters.
247WFor surface waters, monitoring data for nitrates collected over recent years are analysed statistically to identify monitoring points exceeding the level of 50 mg per litre referred to in the directive. In addition, trend analysis methods will be used to identify any additional monitoring points that can be expected to exceed 50 mg per litre in the future.
For ground waters, monitoring data from existing boreholes are processed using mathematical modelling to predict where ground water can be expected to exceed the level of 50 mg per litre, either now or in the future, as a result of nitrate leaching from land.
For inland, coastal and estuarine waters the Environment Agency consider a variety of criteria to assess whether waters are eutrophic or may become eutrophic if no action is taken. These criteria include: nutrient concentrations; occurrence and duration of algal blooms; low dissolved oxygen concentrations; changes in fauna, plant growth and algal growth; and occurrence and magnitude of paralytic shellfish poisoning. Only those waters where nitrate is considered to be a factor causing eutrophication are included for the purposes of designating nitrate vulnerable zones.