Freshwater - State and impacts (Slovakia)
Figure 1 - The surface water bodies in SR 2007
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In 2009, the natural resources of groundwater in Slovakia were set at 11 042 l.s-1. More than 50 % of this volume represented documented usable volumes of groundwater.
A significant part of the Slovak surface water flows in from the neighbouring states and the usability of this fund is limited. In total, the long-term inflow average is approximately 2 514 m3.s-1 of water, which is about 86 % of our total surface water. In the long term, there is approximately 398 m3.s-1 of water springing in Slovakia, which represents 14 % of the water fund. In 2009, the annual inflow to Slovakia was 71 767 million m3. Run-off from the territory was 85 546 million m3.
The groundwater quality is, in the long-term, favourable in Slovakia. In 2009, groundwater pollution observed in objects situated near strong pollution sources was, in most cases, caused by over-limit concentrations of Fe, Mn, NH4, NO3-, Cl-, and SO42-. Sporadically, excessive concentrations of trace elements Al, As, Pb, Hg and Sb occur in the groundwater.
Good chemical status has been classified in 82.7 % of groundwater bodies representing 76.4 % of the total area of groundwater bodies in Slovakia. The major pollutants are sulphates, chlorides, nitrates, ammonia, pesticides, trichloroethene, and tetrachloroethylene.
Anthropogenic activities realised in river basins may result in a deterioration of surface water quality with detrimental effects on ecosystems.
On the basis of the preliminary evaluation of the monitoring results of surface water status performed in 2007, it is possible to state that 1 139 water bodies out of the total number of 1 761 water bodies (circa 65 %) have been classified as having high or good ecological status (or potential). The remaining water bodies have been classified as having worse than good status. Figure 1 shows the water bodies by number classified into the individual ecological status classes.
The chemical status of surface water bodies has been evaluated on the basis of monitoring results at 67 sampling sites covering 46 surface water bodies in 2007. Sampling sites were situated at the localities of their assumed source and at the borders with neighbouring countries. Twenty-four surface water bodies out of the total number of 46 surface water bodies have been evaluated as failing to achieve good chemical status and 22 surface water bodies have been classified into the good chemical status class.
(see Figure 1): The ecological status/potential assessment of surface water bodies in the Slovak Republic expressed by water body quantities (2007)
Link to SEA information: http://www.sazp.sk/public/index/go.php?id=1779&lang=sk
Link to SHMI information: http://www.shmu.sk/sk/?page=1542
Link to WRI information: http://www.vuvh.sk/rsv2/index.php?option=com_content&view=article&id=67&Itemid=87
State and trends of nutrient concentration
In vulnerable zones, nitrates were observed in the network of 560 groundwater objects. During the period 2004–07, there were observations of exceedances in the nitrate limit value (50 mg /l) in 49 objects, i.e. 8.75 % of objects (Table 1).
Table 1: Groundwater nitrate pollution in vulnerable zones of Slovakia
Source: SHMI, WRI
Link to Enviroportal - Environmental Indicators (in Slovak):
Link to SEA information: http://www.sazp.sk/public/index/go.php?id=1167&idl=1167&idf=638&lang=sk
In the case of surface waters in sensitive areas, including vulnerable zones, nitrates were observed in 224 surface water sampling sites and chlorophyll a, as an indicator of trophic status, was observed in 49 sampling sites. During the period 2004–07, the annual average nitrate concentration in the highest number of sampling sites (74 %) ranged from 2–9.99 mg/l. Exceedances over 50 mg/l were observed in none of the sampling sites. As for chlorophyll a, the results showed that the highest numbers of sampling sites were classified into mesotrophic status (46.9 %), eutrophic status was observed in 18.36 % sites. There were no sampling sites classified as having hypertrophic status.
Link to Enviroportal - Environmental Indicators (in Slovak): http://enviroportal.sk/indikatory/detail.php?id_indikator=1827#