Condition of the groundwater. Economic and social consequences of the deterioration of groundwater quality

The assessment of phreatic groundwater quality is carried out within large hydrographical basins, by morphological units and aquifer (underground) structures, using hydrogeological plants including one or more prospecting drillings.
Several types of hydrogeological stations have been developed and used to monitor the phreatic aquifers, such as:

• category 1, located on the fluviatile valleys of the main rivers and nearby the lakes intended to survey the link between groundwater and surface water;
• category 2, located on the plain in between river areas, intended to survey the groundwater regime in relation with climate factors;
• located in the main groundwater tapping areas to survey the effect of utilization on the groundwater regime;
• experimental stations for special purposes i.e. groundwater research related to the balance assessment, pollution propagation, etc;
• located around important industrial units.

The deep drillings within the National hydrogeological network investigate unknown areas from the deep groundwater layers taking into account the information obtained from previously performed research or use oriented hydrogeological drillings. These assess the behaviour of groundwater under natural conditions. Some stations are located in deep groundwater catchment areas aiming to assess the effect of utilization on the condition of groundwater.

The measurement programme within the National hydrogeological network consists in: measurements of the water level – each 3 days, 6 days or 15 days, depending on the level fluctuation amplitude; temperature measurements each 6 days in specific drillings; experimental pumping in order to determine the characteristics of the hydrogeological layer; and periodical sampling in order to determine the physico-chemical characteristics of the water.

At present, the state owned hydrogeological networks drillings are used to monitor the quality of phreatic water.

However, a reconsideration of the spatial structure of the phreatic groundwater sub-system is going to be developed under the management of the "Romanian Water Authority" Company in order to optimise the activity of acknowledging the quality of groundwater at basin compartment level, aiming to improve the methodology as well.

Moreover, measurements and periodical surveys are undertaken in the pollution drillings located around highly polluting sources, in every hydrographical basin, in order to survey the pollution of the phreatic groundwater due to anthropogenic activities, and ascertain the impact that pollution sources may have on the groundwater.

Groundwater quality at national level

Upon a global assessment of the available information, by hydrographical basins, a first finding should be mentioned concerning the critical condition of the groundwater quality in many regions of Romania, i.e. the severe exogene anthropogenic impact, in spite of the decline of industrial activity and consequent decrease of the discharge of pollutants in the natural receivers. A number of quantitative and qualitative changes have occurred in the natural groundwater regime due to the execution of some hydro-improvement and hydrotechnical works, including tapping, as well as owing to the pollution of phreatic water in particular. In some regions, significant increases of the piezometric levels occurred e.g. in the Bailesti, Romanati and Baragan plains (2-15 m), and southern Dobrogea (3-10 m). These phenomena are due to the inadequate design, execution and use of the irrigation systems located in these areas.

In other areas, significant decreases of the piezometric level occurred due to excessive groundwater catchment (e.g. Bucharest – "Fratesti Layers": 20–50 m decrease of the level) or owing to mining area drying (e.g. Rovinari: over 80 m decrease). The most severe danger in this case is the accelerated flow of polluting water into depression areas, and drastic reduction of the used flows in the affected areas.

Another important finding relates to the qualitative changes in the groundwater layers, as generated by polluting substances which spoil the physical, chemical and biological characteristics of the water.

Consequently, the main hydrostructures have been subject in the long run to a water contamination process by nitrates (NO₃). But the pollution levels are not similar in all affected areas, e.g. there are regions where the groundwater is highly polluted, the concentrations exceeding the limits specified by the STAS 1342-91 standard for this indicator (Somes lower plain, Crasna corridor, middle area of the Banat Plain; Mures corridor on the Reghin – Ludus stretch; Tarnava Mare corridor downstream of Sighisoara); mountain and under-mountain depression areas drained by Olt-Ciuc, Brasov, Fagaras and Cibin; lower Danube Plain, piedmountaneous Ploiesti Plain; Ialomita corridor on the Urziceni-Tandarei corridor; northern Baragan Plain; Siret corridor on the downstream Roman-upstream Adjud stretch; Bistrita corridor downstream of Piatra Neamt; Trotus corridor on the downstream Onesti-upstream Adjud stretch; Sitna depression - downstream of Botosani; Bahlui corridor downstream of Podu Iloaiei; Prut corridor downstream of Ungheni; eastern Covurlui Plain, lower Siret Plain as well as the eastern half of southern Dobrogea. There are regions where the value is below the maximum admissible concentration as specified by STAS 1342-91, i.e. 45 mg/l.

The causes that generated the phreatic water contamination by nitrates are manifold and cumulative.

Thus, a significant pollution source is the permanent soil washing by the atmospheric rainfall contaminated by nitrogen oxides (NO₂).

Another pollution source is the surface water (rivers, lakes) in which nitrates loaded wastewater was discharged. The alleatory sources generated by the use of fertilizers may be added to the above-mentioned permanent sources. On the agricultural lands, the nitrate concentrations range frequently around the value of 100 mg/l and may reach values of about 300 mg/l. Such contaminated groundwater is of an insular type and the use of water for domestic and farming purposes has contributed to maintaining the polluted lands within the limits of the localities.

Concerning the phreatic groundwater contamination by phosphates (PO₄^3-), the damaged surfaces are less extended, and there are many aquifer layers where this parameter has not been ascertained by the measurements performed in 2000. Moreover, for this quality indicator, the phreatic groundwater pollution conditions are generally similar to those assessed in the case of the nitrates.

A very different situation occurs in the case of intensive aquifer layer contamination by organic matter, ammonia and bacteria.

The most severe quality depreciation has been identified in the rural built-up area, where the lack of minimum public facilities allow for the liquid waste to reach directly into the groundwater (by means of pervious privies or stretch ditches); or indirectly (from manure deposits, improvised landfills etc).

Depending on the factors generating the groundwater pollution, analysing the existing data within each hydrographical basin, the following types of pollution have been assessed: by oil products, products resulting from industrial process, chemical products, used in agriculture, domestic products, zootechnics products, mixed products e.g.

• pollution by oil products and phenol compounds of the groundwater within the Prahova-Teleajen alluvial cone on a surface of about 70 km², due to Petrobrazi, Astra and Petrotel Ploiesti refineries;
• pollution by products used in agriculture such as fertilizers or pest killers (nitrogen compounds – NH₄, NO₂ and NO₃, phosphates, pesticides etc), either on the areas where such producers are located (AZOMURES, ARCHIM Arad, DOLJCHIM Craiova, OLTCHIM Rm.Valcea, AZOCHIM Roznov etc) or in the fields, due to inadequate use. Such diffuse pollution mainly damaged the individual wells in the rural areas, but also groundwater catchments;
• pollution by products resulting from industrial process, including a high number of pollutants that contaminate the areas around large industrial platforms such as: VICTORIA, Fagaras, Codlea, Tohanu Vechi, Zarnesti, Bod, Isalnita Craiova etc);
• pollution by domestic and zootechnics products (organic substances, nitrogen compounds, bacteria etc) that contaminate the areas around big cities (Pitesti, Oradea, Bucharest, Cluj, Suceava etc) and large animal breeding farms (Carei, Palota, Cefa, Halciu, Bontida, Bailesti).

Upon performing an analysis at national level, relying on the data presented by the basin Water Departments in 2000, concerning the deep and phreatic layer drilling pollution excluding the pollution drilling located around large industrial platforms, and referring to 4 of the pollutants included in the undesirable parameters class i.e. ammonia, nitrates, organic matter such as CCO-Mn and phosphates, the following may be concluded:

Concerning the STAS 1342/91 standard for drinking water, used as a base for the interpretation of the results acquired from the monitoring and analysis of the water samples obtained by drilling, the cases of exceeding STAS admissible limits (as percentage) are a follows:

• phreatic layer: for NH₄ in 77.78 % of the drillings; for NO₃ in 47.7%; for CCO-Mn in 80.78% of the total analysed drillings and for PO₄ in 51% of the drillings;
• deep layer: for NH₄ in 68.47% of the studied drillings; for CCO-Mn in 53.26% of the drillings; for NO₃ in 36.1% and for PO₄ in 38% of the drillings.

These data show that mainly phreatic aquipher resources hold a high risk of pollution, both on the long and short term. For this reason, in many areas these cannot be used as sources of water supply for the population.

It should be mentioned that the pollution of the phreatic resource is often an almost irreversible phenomenon and the treatment of such water is extremely difficult or even impossible, with serious consequences when it is used as drinking water.

Thus some water catchments in the phreatic aquifer were discarded, and new topping fronts had to be found and put into operation, all of which involved significant efforts and costs.

For this reason, within the water quality management policy, measures to prevent the quality degradation of the water resources should be a priority.