ANALYSES OF THE NITRATES CONCENTRATIONS EVOLUTION IN WATER RESOURCES ACCORDING WITH THE EUROPEAN DIRECTIVES REQUIREMENTS

Elena Tuchiu, Elvira Marchidan

National Administration “Apele Romane”

Abstract

One of the most significant water management issues is water pollution with nitrates. Council Directive 91/676/EEC (Nitrates Directive) concerning the protection of waters against pollution caused by nitrates from agricultural sources was fully transposed in the national legislation through Government Decision nr. 964/2000 on the approval of the Action Plan for the water protection against pollution with nitrates from agriculture sources. The surveillance of nitrates level in surface waters and in groundwater in the monitoring sites and checking the surface waters trophic status (both fresh and marine/coastal waters) are done for identification and mapping the affected waters or those which could be affected by pollution with nitrates. This is necessary, in order to protect human health and aquatic ecosystems to reduce water pollution caused or induced by nitrates from agricultural sources and to prevent further such pollution. Maximum value for nitrates in drinking water (Law no. 458/2002 which transpose Drinking Water Directive), in surface water (GD 100/2002 which transpose the European Directive 75/440/EEC) and in groundwater (GD 53/2009 that transpose European Directive 2006/118/EC) is 50 mg/l NO3. In order to identify the water affected or likely to be affected by nitrates from agricultural sources, the following criteria are used:
- Exceeding of the limits set by legislation for surface water used for drinking purposes;
- Exceeding of the limits set by legislation for groundwater used for drinking water abstraction;
- Freshwater sources (natural lakes, reservoirs, canals), coastal and marine waters are eutrophic or may become eutrophic in the near future.Based on analytical data (average, minimum and maximum values) obtained in each monitoring section, the surface water and groundwater quality assessment should be done. Very important is also the trend assessment of the nitrates concentrations both in surface and groundwater. For this purpose, the monitoring data considered are physico-chemical parameters: nitrates, nitrites, total nitrogen, phosphates and total phosphorous, dissolved oxygen and organic substances (measured through BOD5), chlorophyll “a” (in those stations were the risk of eutrophication exists). To identify the eutrophication phenomena, is necessary to use the monitoring data obtained especially in summer period.

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