PART 4

Ground Water Quality

4.1. Hungarian territory

The subject of the joint ground water quality monitoring on the Hungarian side consists of 22 wells, from among 16 objects are ground water quality observation wells, situated in the upper layer of the gravel sediments, and 6 wells are used for drinking water supply (Tab. 4-1). Samples were taken 4 times during the year. In case of the Darnózseli I drinking water well only one sample was taken. Dissolved oxygen measurements in ground water quality observation wells were carried out again in 2002.

The water quality monitoring in observation wells was carried out by the North-Transdanubian Authority for the Environment Protection, the water quality monitoring in wells for drinking water supply were carried out by Regional Waterworks Companies. Wells included in the ground water quality monitoring are situated on the Fig. 4-1.

  Table 4-1: List of monitoring objects on the Hungarian territory

In compliance with the point 1 of the Recommendations of the Joint Annual Report in 1999 long-term evaluation of the ground water quality has been carried out in the Hungarian National Annual Report for the year 2002. The detailed evaluation as well as the data series and graphs were presented in the Hungarian National Annual Report for the year 2002. In the present Joint Report the ground water quality evaluation of four selected observation wells is given.

Well No. 9327, locality: Dunakiliti

On the basis of long-term data, seasonal, periodical variation of water quality was markedly observed in this ground water observation well. The water is of low salt content, similarly to the Danube water. Periodicity appears mainly in water temperature, conductivity as well as in the sodium, chloride and nitrate ion concentrations. From among ion composition slight increase of sodium and chloride concentrations, as well as phosphate concentration was recorded. Regarding the ground water quality limits (Tab. 4-3) the water of this well meets the requirements for drinking water.

Well No. 9413, locality: Sérfenyősziget

The temperature and pH of water showed similar fluctuation as in the previous year, with a peak in the summer. According to the conductivity measurements the salt concentration fluctuates slightly. The water is of medium salinity and according to the mean values decreasing tendency can be observed. Concerning the drinking water limit values the nitrite ion content was above the limit, while ammonium and nitrate concentrations, as well as the organic contamination stayed under the limit values. The iron content shows a decreasing tendency and is under the limit value, while the manganese content seasonally fluctuates and the values are above the limit value.

Well No. 9430, locality: Kisbodak

The temperature of the water is stable and does not follow changes in air temperature. The water has moderate salt content. The continuous decrease of salt content slowed down, even slightly increased in comparison to the previous year, which is followed by similar changes in calcium and hydro-carbonate concentrations. The quantity of different nitrogen forms and organic material is permanently low; concentrations are below the agreed limits. High iron and manganese concentrations do not meet the drinking water quality criteria. The iron concentration shows significant fluctuation from year to year, while the manganese concentration is slightly decreasing.

Well No. 9456, locality: Ásványráró

The slight increase of conductivity values since 1996 has stopped. The water temperature is stable and the water has a moderate salt content wit a slight seasonal fluctuation. From among the nitrogen forms the ammonium ion concentration was above the limit value and the increasing, unfavourable tendency continued. The nitrite and nitrate pollution was not characteristic in this water. The organic material content was under the limit value and showed a decreasing tendency. The manganese content in the water was under the limit value, however a slight increase was observed. The iron concentration, in contrary to the previous year, fluctuated above the limit value again.

Summarizing the results of long-term water quality observation on the selected 16 observation wells it can be stated that there were some changes in case of certain wells.

Regarding the salt content in case of wells No. 9368 at Rajka and No. 9430 at Kisbodak decreasing tendency has stopped and a slight increase was registered. Increasing tendency continued in case of wells No. 9536 at Püski, 9435 at Arak, 9475 at Győrzámoly, while some decline occurred at wells No. 9413 at Sérfenyősziget and No. 9418 at Mosonmagyaróvár.

Concerning the iron and manganese concentrations increase in case of wells No. 9418 at Mosonmagyaróvár, 9435 at Arak, 9456 and 9457 at Ásványráró, 9475 and 9480 at Győrzámoly and 9484 at Vámosszabadi was recorded, while decreasing tendency of the iron content continued at wells No. 9310 at Rajka, 9413 at Sérfenyősziget and in case of manganese content at the well No. 9430 at Kisbodak.

Some worsening concerning the organic material content was observed in wells No. 9310, 9368 and 9379 at Rajka, while improving tendency or no remarkable changes were detected in other wells in 2002.

Ammonium ion concentrations increased in wells No. 9331 at Dunakiliti, 9536 at Püski, 9456 at Ásványráró, 9475 at Győrzámoly and 9484 at Vámosszabadi, while they decreased in wells No. 9368 at Rajka, 9435 at Arak and 9457 at Ásványráró.

The nitrate concentrations further increased in wells No. 9310 and 9368 at Rajka, 9331 at Dunakiliti, 9435 at Arak, and 9484 at Vámosszabadi, while evenly decreasing tendency occurred in wells No. 9379 at Rajka and 9418 at Mosonmagyaróvár.

High ammonium ion concentration, along with nitrite, nitrate, phosphate and organic material pollution in the well No. 9368 at Rajka has local origin and probably comes from agricultural activity in this area. Similarly it is also probable that the high nitrite, nitrate, phosphate contents above the limit values in the well No. 9458 at Ásványráró are local and caused by agricultural pollution as well.

Except the wells having local ground water contamination it can be concluded that in nitrite and nitrate concentrations in examined wells are lower than in the surface water. The low dissolved oxygen; high iron and manganese concentration – sometimes above the limit value – are characteristic for the ground water of the area in general. The higher sulphate concentration might indicate anaerobic conditions in the ground water.

These changes in the water quality might reflect the integrated effect of the changes in the area, in which the varied ground water flow directions, affected by the water supply, might also play role.

Evaluating the ground water quality data from wells used for drinking water supply it can be stated that the wells in the area of Győr show some iron, manganese and ammonium pollution. The salt content, the iron and manganese concentrations are higher in wells at Győr-Révfalu water source, than in wells at Győr-Szőgye, which are deeper. The other monitored wells have invariably excellent ground water quality and the water compositions are characterised by high degree of stability.

4.2. Slovak territory

For the purposes of the Slovak-Hungarian monitoring data of the Western Slovakia’s Waterworks Enterprise (ZVS), the Waterworks Enterprise Bratislava (BVS), Slovak Hydro-meteorological Institute (SHMÚ) and Ground Water Consulting were used. The objects of Waterworks Enterprises are used for drinking water supply; the other objects are observation wells (Tab. 4-2).

The evaluation for every well included in the joint monitoring, similarly to the previous year, was done for period of ten years (1.10.1992-31.10.2002) in the National Annual Report. The evaluation in this report is focused mainly to the ground water quality in waterworks, which is more representative because of their continuous pumping. All data from each well were interpreted in relation to the agreed limits for drinking water presented in Tab. 4.3.

In the ground water quality monitoring in hydrological year 2002 there was one significant change. The drinking water supply well No. 906 was put out of operation and it was substituted by well No. 907, which has similar qualitative parameters in long term.

Since January 2002 there were some changes in ground water quality limits set by the Ordinance No. 29/2002 of the Slovak Ministry for Public Health. A notice “SK” in the table 4.3 labels parameters where the limits of Slovak standard differ from the EU limits.

  Table 4-2: List of monitoring objects on the Slovak territory

Short evaluation of the ground water quality in monitoring objects included in the data exchange

In comparison to the previous year there were no significant changes in the parameters observed during the hydrological year 2002. Long-term evaluation was done in the Slovak National Annual Report in 2002 for ten years period, comparing the data from all monitored objects with the agreed limit values for ground water quality. Ground water quality at drinking water sources is very stable in long term and satisfies the agreed ground water quality limits. The only exceptions are the waterworks Bodíky (No. 485), where manganese concentrations 15 times and ammonium concentration once exceeded the limit value during the whole observation period, and the waterworks Rusovce (No. 102), where sulphate concentration once exceeded the limit value. (For details look into the table “Exceedings of the Standard’s limits in ground water quality parameters” in the Graphical Appendix of the Slovak National Annual Report in 2002.)

The ground water quality in observation objects is more influenced by local impacts. From the table “Exceedings of the Standard’s limits in ground water quality parameters” in the Graphical Appendix of the Slovak National Annual Report in 2002 results, that agreed limits are exceeded in the case of ammonium concentration (objects No. 87, 329, 872, 888, 899), nitrite concentration (objects No. 170, 234, 872), manganese (objects No. 3, 170, 899), iron (objects No. 170, 872), sporadically magnesium concentration (objects No. 3, 899) and COD_Mn (objects No. 170, 888). Values of the basic physical and chemical parameters, cations and anions and the oxygen regime parameters at the remaining objects satisfy the agreed limits for ground water quality.

Ground water quality evaluation at waterworks for drinking water supply.

Right side of the Danube

(Waterworks No. 907 – Bratislava, 102 – Rusovce, 2559 – Čunovo)

The water quality at waterworks Rusovce and Čunovo is very similar. Damming the Danube had a great influence on the ground water quality due to the changed infiltration conditions and changed ground water flow direction, especially at the waterworks Rusovce. After the damming the concentration of cations (Na, Ca, Mg) and anions (Cl, SO₄, HCO₃) significantly decreased, which resulted in decreased of conductivity. Similar process, but in less extent was observed at the waterworks Čunovo. In the period of 1998-1999 the ground water quality has stabilised and the cations and anions fluctuate in a narrower range. On both waterworks the nitrate concentrations, as well as the organic contamination, expressed by COD_Mn and TOC, decreased and got stable.

The situation at the waterworks No. 907 – Bratislava differs. Values of respective parameters fluctuate a lot during the year. The waterworks is situated near the Danube and concentrations of observed parameters follow the fluctuation of these parameters in the Danube. Based on the measured values it can be stated that increase of magnesium concentration, and decrease of sulphates and organic contamination occurred.

Left side of the Danube

(Waterworks No. 116 – Kalinkovo, 105 – Šamorín, 467 – Dobrohošť, 485 – Bodíky, 103 – Gabčíkovo)

The ground water quality at waterworks situated on the left side of the Danube was not influenced to that extent like the quality at the waterworks on the right side. The ground water quality at the waterworks No. 116 - Kalinkovo and No. 105 - Šamorín is similar. Some differences (at Kalinkovo slight increase, at Šamorín slight decrease) exist in calcium, magnesium and hydrocarbonate concentrations. Manganese concentrations at Kalinkovo fluctuate around 0.2 mgl^-1. On both waterworks the concentrations of nitrates and sulphates decrease; the concentrations of silicates and COD_Mn slightly increase. TOC at Kalinkovo increases, at Šamorín the increase of TOC stopped in 2000 and the concentrations have begun to decrease.

The Gabčíkovo waterworks is situated in the area drained by the tailrace canal and the water comes to the wells from the inland area. The conductivity, content of dissolved solids, chlorides and sulphates slightly increase in long term. This fact shows that the amount of ground water coming from the inland area gradually increases. The oxygen content is low, but the nitrate concentration slightly increases and the TOC and COD_Mn values decreasing to 1 mgl^-1. From this point of view the oxidative capacity for organic carbon oxidation slightly improves. The iron content is below the detection limit, however the manganese content rarely exceeds the given limit.

The ground water quality at waterworks No. 467 – Dobrohošť and No. 485 – Bodíky is strongly influenced by the local conditions. Although the waterworks are close to each other, based on the measurements it can be stated that tendencies in ground water quality parameters are different: decrease of conductivity, calcium, sulphate and hydrocarbonate concentrations at Dobrohošť, increase of calcium, manganese, sulphate and hydrocarbonate concentrations at Bodíky. At waterworks Bodíky the ammonium concentrations fluctuate in a wide range from 0.05 to 0.57 mgl^-1, manganese concentrations fluctuate mainly from 0.2 to 0.8 mgl^-1. Nitrate concentrations decrease on both waterworks during the whole monitoring period, however since 2001 a slight increase is observed. COD_Mn and TOC concentrations slightly decrease on both waterworks.

4.3. Conclusions

In conclusion it can be stated that the basic physical and chemical parameters, cations, anions and oxygen regime parameters satisfies the agreed ground water quality limits at all monitoring objects. The nutrient content satisfies the agreed limits in long term as well, except the nitrates in object No. 170 and ammonium content in object No. 899. The iron and manganese contents satisfy the agreed limit on most of the monitored objects, however manganese content exceeds the given limit in objects No. 116, 485, 899 and 262 and the iron content exceeded the limit once in the year 2001 in objects 170, 262 and 234 and in object No. 872 in the period 1999-2001.

Limits for drinking water quality used for evaluation in the frame of joint monitoring are given in the following table:

Table 4-3: Ground water quality limits for drinking water.

EU-European standard, SK-Slovak standard, H-Hungarian standard

IV          – indicating value                  RV     – recommended value

LV         – limit value                            HLV    – highest limit value

	Fig. 4-1 Monitoring network of observation objects agreed in the frame of the Joint monitoring