 | 1. For the purpose of designating and revising the designation of vulnerable
zones, Member States shall:
 | (a) within two years of notification of the Directive, monitor the nitrate
concentration in freshwaters over a period of one year:
 | (i) at surface water sampling stations, laid down in Article 5 (4) of Directive
75/440/EEC and/or at other sampling stations which are representative of surface
waters of Member States, at least monthly and more frequently during flood
periods; |
| (ii) at sampling stations which are representative of the groundwater aquifers
of Member States, at regular intervals and taking into account the provisions of
Directive 80/778/EEC; |
|
| (b) repeat the monitoring programme outlined in (a) at least every four years,
except for those sampling stations where the nitrate concentration in all
previous samples has been below 25 mg/l and no new factor likely to increase the
nitrage content has appeared, in which case the monitoring programme need be
repeated only every eight years; |
| (c) review the eutrophic state of their fresh surface waters, estuarial and
coastal waters every four years. |
|
