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 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 adopted in the national legislation through Government Decision nr. 964/2000 for the approval of the Action Plan for the water protection against pollution with nitrates from agriculture sources.
The surveillance/monitoring of nitrates concentration 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 in order to identify the affected waters or those which could be affected by pollution with nitrates. This is necessary for establishing actions for ensuring reduction of pollution caused or induced by nitrates from agricultural sources and to prevent further such pollution in order to ensure human health and aquatic ecosystems protection. 
To identify the water affected or likely to be affected by nitrates from agricultural sources, the following criteria are used:

• whether surface freshwaters, in particular those used or intended for the abstraction of drinking water, contain or could contain, if action is not taken, more than the concentration of 50 mg/l;
• whether groundwaters contain more than 50 mg/l nitrates or could contain more than 50 mg/l nitrates if action is not taken;
• whether natural freshwater lakes, other freshwater bodies, estuaries, coastal waters and marine waters are found to be eutrophic or in the near future may become euthropic if action is not taken.

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). In order to identify the eutrophication phenomena, it is necessary to use the monitoring data obtained especially in summer period (chlorophyll a) .