River basin
Water pollution in the Hron basin
- Sites in the 2025 yearbook
- 50
- Failed the standard (72%)
- 36
- Counted in the score
- 25
River basin overview
In the Hron basin the SHMÚ yearbook has 50 monitoring sites; in 2025, 36 of them (72%) failed the standard for at least one indicator. 25 are counted in the scores of the fishing districts.
Watercourse profile of Hron
SHMÚ sites from source to mouth
Watercourse profile from source to mouthnumber of unmet indicators in 2025 at SHMÚ sites
Show sites in the table (23)
- Červená Skala, aboveriver km 269.61 indicator
- Bujakovoriver km 227.21 indicator
- Dubová, bridge (PTCHEM, above)river km 204.52 indicators
- Nemecká, bridge (PTCHEM, below)river km 202.33 indicators
- Medzibrod (bridge)river km 195.71 indicator
- Šalkováriver km 181.61 indicator
- Banská Bystricariver km 175.81 indicator
- Hronsekriver km 165.3no unmet standard
- Zvolen (weir Podharajch)river km 156.52 indicators
- Budčariver km 148.21 indicator
- Trnavá Hora – Jalnáriver km 140.1no unmet standard
- Žiar nad Hronomriver km 131.51 indicator
- Žarnovica, aboveriver km 112.01 indicator
- Banksriver km 93.91 indicator
- Tekovská Breznicariver km 88.9no unmet standard
- Kozárovceriver km 78.8no unmet standard
- Starý Tekov – bridge (below the small hydropower plant)river km 70.5no unmet standard
- Kalná nad Hronomriver km 63.7no unmet standard
- Želiezovce (road bridge Želiezovce – Sikenica)river km 35.6no unmet standard
- above Biotika (CO facility, below)river km 1.96 indicators
- Kamenica nad Hronomriver km 1.75 indicators
- Závadka nad Hronomriver km 0.52 indicators
- below Biotika (road bridge, below)river km 0.510 indicators
- standard not met
- no unmet standard
- site not in the yearbook
Year-by-year trend
Share of sites in the river basin that failed the standard
- 202225 of 2793%
- 202338 of 4486%
- 202438 of 5175%
- 202536 of 5072%
Fishing district map
Fishing districts in the “Hron river basin” by nearest SHMÚ site
Detailed filtersregion, district, riverbed, depth, shading, satellites, water chemistry and pollution, fish, geology
1445fishing districts
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The color of the fishing district line shows the number of indicators that failed the standard at the nearest SHMÚ site (2025). Gray fishing districts have no site with the same watercourse name nearby. You can also switch the color to groundwater and treatment plants.
Worst sites in the river basin
Click to expand the history by year
Kremnica, belowKremnický potok, river km 12.68 indicators in 2025
Indicator2022202320242025Oxygen and organic matterCOD (chemical oxygen demand)●standard not met–site not in the yearbook·standard met●standard not metBOD₅ (biochemical oxygen demand)·standard met–site not in the yearbook·standard met●standard not metNutrients and nitrogenammonium●standard not met–site not in the yearbook·standard met●standard not mettotal phosphorus●standard not met–site not in the yearbook·standard met●standard not metnitrites·standard met–site not in the yearbook·standard met●standard not metMetalscopper·standard met–site not in the yearbook●standard not met·standard metlead·standard met–site not in the yearbook●standard not met·standard metzinc·standard met–site not in the yearbook●standard not met·standard metHarmful organic substancesAOX (adsorbable organic halogens)·standard met–site not in the yearbook·standard met●standard not mettotal cyanides·standard met–site not in the yearbook●standard not met·standard metSalts, pH and mineralsS (according to the SHMÚ yearbook)·standard met–site not in the yearbook·standard met●standard not metaluminium·standard met–site not in the yearbook·standard met●standard not metNearest site for the fishing districts: Kremnický potok
Zolná, mouthZolná, river km 0.512 indicators in 2025
Indicator2022202320242025Oxygen and organic mattertotal organic carbon·standard met●standard not met●standard not met·standard metNutrients and nitrogenammonium·standard met·standard met·standard met●standard not metnitrites·standard met●standard not met·standard met·standard metMetalsmercury·standard met·standard met·standard met●standard not metHarmful organic substancesAOX (adsorbable organic halogens)·standard met·standard met●standard not met●standard not metoctylphenol·standard met●standard not met●standard not met·standard metpentachlorophenol●standard not met·standard met·standard met·standard metBiology and bacteriasaprobic index of biosestone·standard met●standard not met·standard met●standard not metPAHs: 9 substances (not counted in the score)
Indicator2022202320242025PAHs (combustion and deposition)benzo(a)pyrene●standard not met●standard not met●standard not met●standard not metfluoranthene·standard met●standard not met●standard not met●standard not metanthracene·standard met·standard met·standard met●standard not metbenzo(b)fluoranthene·standard met·standard met·standard met●standard not metbenzo(ghi)perylene·standard met·standard met●standard not met·standard metbenzo(k)fluoranthene·standard met·standard met·standard met●standard not metphenanthrene·standard met·standard met·standard met●standard not metnaphthalene·standard met·standard met·standard met●standard not metperylene·standard met·standard met·standard met●standard not metPolycyclic aromatic hydrocarbons. The standard for benzo(a)pyrene is extremely low (0.17 ng/l), so most streams exceed it; the main sources are combustion and atmospheric deposition.
Nearest site for the fishing districts: Zolná
The location of the site is only approximate (based on the water body).
Veľký Ďur, aboveĎurský potok, river km 8.16 indicators in 2025
Indicator2022202320242025Oxygen and organic matterBOD₅ (biochemical oxygen demand)–site not in the yearbook–site not in the yearbook·standard met●standard not metCOD (chemical oxygen demand)–site not in the yearbook–site not in the yearbook·standard met●standard not metNutrients and nitrogennitrates–site not in the yearbook–site not in the yearbook●standard not met●standard not mettotal nitrogen–site not in the yearbook–site not in the yearbook●standard not met●standard not metammonium–site not in the yearbook–site not in the yearbook·standard met●standard not metSalts, pH and mineralsconductivity–site not in the yearbook–site not in the yearbook·standard met●standard not metThe location of the site is only approximate (based on the water body).
BudčaHron, river km 148.21 indicator in 2025
Indicator2022202320242025Oxygen and organic mattertotal organic carbon·standard met●standard not met●standard not met·standard metNutrients and nitrogennitrites·standard met●standard not met·standard met·standard metHarmful organic substancesAOX (adsorbable organic halogens)·standard met●standard not met●standard not met●standard not metPAHs: 2 substances (not counted in the score)
Indicator2022202320242025PAHs (combustion and deposition)benzo(a)pyrene●standard not met·standard met●standard not met·standard metfluoranthene●standard not met·standard met●standard not met·standard metPolycyclic aromatic hydrocarbons. The standard for benzo(a)pyrene is extremely low (0.17 ng/l), so most streams exceed it; the main sources are combustion and atmospheric deposition.
Zvolen (near the gauging station)Slatina, river km 1.94 indicators in 2025
Indicator2022202320242025Oxygen and organic mattertotal organic carbon·standard met●standard not met●standard not met·standard metNutrients and nitrogennitrites●standard not met●standard not met●standard not met·standard metHarmful organic substancesoctylphenol·standard met●standard not met·standard met·standard metBiology and bacteriasaprobic index of biosestone·standard met●standard not met·standard met·standard metPAHs: 7 substances (not counted in the score)
Indicator2022202320242025PAHs (combustion and deposition)benzo(a)pyrene●standard not met●standard not met●standard not met·standard metfluoranthene●standard not met●standard not met●standard not met·standard metanthracene·standard met·standard met·standard met●standard not metbenzo(b)fluoranthene·standard met·standard met·standard met●standard not metbenzo(ghi)perylene·standard met·standard met●standard not met·standard metbenzo(k)fluoranthene·standard met·standard met·standard met●standard not metperylene·standard met·standard met·standard met●standard not metPolycyclic aromatic hydrocarbons. The standard for benzo(a)pyrene is extremely low (0.17 ng/l), so most streams exceed it; the main sources are combustion and atmospheric deposition.
The location of the site is only approximate (based on the water body).
Červená Skala, aboveHron, river km 269.61 indicator in 2025
Indicator2022202320242025Oxygen and organic mattertotal organic carbon·standard met●standard not met●standard not met·standard metNutrients and nitrogennitrites●standard not met·standard met·standard met·standard metHarmful organic substancesAOX (adsorbable organic halogens)·standard met●standard not met●standard not met●standard not metThe location of the site is only approximate (based on the water body).
Banská BystricaHron, river km 175.81 indicator in 2025
Indicator2022202320242025Oxygen and organic mattertotal organic carbon·standard met●standard not met●standard not met·standard metNutrients and nitrogennitrites●standard not met·standard met·standard met·standard metMetalsarsenic·standard met·standard met·standard met●standard not metHarmful organic substancesAOX (adsorbable organic halogens)·standard met●standard not met●standard not met·standard metPAHs: 1 substance (not counted in the score)
Indicator2022202320242025PAHs (combustion and deposition)benzo(a)pyrene·standard met·standard met●standard not met·standard metPolycyclic aromatic hydrocarbons. The standard for benzo(a)pyrene is extremely low (0.17 ng/l), so most streams exceed it; the main sources are combustion and atmospheric deposition.
Kvetnianka, mouth (Bíňa, above)Kvetnianka, river km 0.72 indicators in 2025
Indicator2022202320242025Oxygen and organic matterCOD (chemical oxygen demand)–site not in the yearbook●standard not met·standard met●standard not mettotal organic carbon–site not in the yearbook●standard not met·standard met·standard metNutrients and nitrogennitrates–site not in the yearbook●standard not met·standard met●standard not metSalts, pH and mineralspH–site not in the yearbook●standard not met·standard met·standard metconductivity–site not in the yearbook●standard not met·standard met·standard metcalcium–site not in the yearbook●standard not met·standard met·standard metPAHs: 1 substance (not counted in the score)
Indicator2022202320242025PAHs (combustion and deposition)benzo(a)pyrene–site not in the yearbook●standard not met·standard met·standard metPolycyclic aromatic hydrocarbons. The standard for benzo(a)pyrene is extremely low (0.17 ng/l), so most streams exceed it; the main sources are combustion and atmospheric deposition.
Slatina, mouthSlatina, river km 0.32 indicators in 2025
Indicator2022202320242025Oxygen and organic mattertotal organic carbon·standard met·standard met●standard not met·standard metNutrients and nitrogennitrites●standard not met●standard not met·standard met·standard metHarmful organic substancesAOX (adsorbable organic halogens)·standard met·standard met●standard not met●standard not metSalts, pH and mineralspH·standard met·standard met·standard met●standard not metPAHs: 3 substances (not counted in the score)
Indicator2022202320242025PAHs (combustion and deposition)benzo(a)pyrene●standard not met·standard met●standard not met·standard metfluoranthene●standard not met·standard met●standard not met·standard metbenzo(b)fluoranthene●standard not met·standard met·standard met·standard metPolycyclic aromatic hydrocarbons. The standard for benzo(a)pyrene is extremely low (0.17 ng/l), so most streams exceed it; the main sources are combustion and atmospheric deposition.
The location of the site is only approximate (based on the water body).
BP Hrona (Dúbrava), below Biotika (road bridge, below)BP Hrona (Dúbrava), river km 0.510 indicators in 2025
Indicator2022202320242025Nutrients and nitrogentotal nitrogen–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not mettotal phosphorus–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metMetalsarsenic–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metnickel–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metHarmful organic substancesAOX (adsorbable organic halogens)–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metSalts, pH and mineralschlorides–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metfluorides–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metdissolved solids, ignited (550 °C)–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metsulfates–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metcalcium–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metBP Hrona (Dúbrava), above Biotika (CO facility, below)BP Hrona (Dúbrava), river km 1.96 indicators in 2025
Indicator2022202320242025Oxygen and organic matterBOD₅ (biochemical oxygen demand)–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not mettotal organic carbon–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metNutrients and nitrogenammonium–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metSalts, pH and mineralsdissolved solids (105 °C)–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metconductivity–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metPAHs: 1 substance (not counted in the score)
Indicator2022202320242025PAHs (combustion and deposition)benzo(a)pyrene–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metPolycyclic aromatic hydrocarbons. The standard for benzo(a)pyrene is extremely low (0.17 ng/l), so most streams exceed it; the main sources are combustion and atmospheric deposition.
ŠalkováHron, river km 181.61 indicator in 2025
Indicator2022202320242025Oxygen and organic mattertotal organic carbon·standard met●standard not met●standard not met·standard metHarmful organic substancesAOX (adsorbable organic halogens)·standard met·standard met●standard not met●standard not metFarnáKvetnianka, river km 13.93 indicators in 2025
Indicator2022202320242025Oxygen and organic matterCOD (chemical oxygen demand)–site not in the yearbook–site not in the yearbook·standard met●standard not metNutrients and nitrogennitrates–site not in the yearbook–site not in the yearbook●standard not met●standard not metSalts, pH and mineralsconductivity–site not in the yearbook–site not in the yearbook·standard met●standard not metThe location of the site is only approximate (based on the water body).
Dubová, bridge (PTCHEM, above)Hron, river km 204.52 indicators in 2025
Indicator2022202320242025Oxygen and organic mattertotal organic carbon–site not in the yearbook●standard not met·standard met·standard metHarmful organic substancesAOX (adsorbable organic halogens)–site not in the yearbook●standard not met●standard not met·standard metheptachlor–site not in the yearbook·standard met·standard met●standard not metSalts, pH and mineralsS (according to the SHMÚ yearbook)–site not in the yearbook·standard met·standard met●standard not metpH–site not in the yearbook●standard not met·standard met·standard metNearest site for the fishing districts: Hron č. 8, Hron č. 9a, Hron č. 9b, Hron č. 9c
The location of the site is only approximate (based on the water body).
Vajskovský potok, mouthVajskovský potok, river km 0.21 indicator in 2025
Indicator2022202320242025Metalsarsenic●standard not met●standard not met●standard not met●standard not metNearest site for the fishing districts: Vajskovský potok
Nemecká, bridge (PTCHEM, below)Hron, river km 202.33 indicators in 2025
Indicator2022202320242025Oxygen and organic mattertotal organic carbon–site not in the yearbook●standard not met·standard met·standard metHarmful organic substancesAOX (adsorbable organic halogens)–site not in the yearbook·standard met●standard not met·standard metheptachlor–site not in the yearbook·standard met·standard met●standard not metSalts, pH and mineralsS (according to the SHMÚ yearbook)–site not in the yearbook·standard met·standard met●standard not metpH–site not in the yearbook●standard not met·standard met·standard metPAHs: 1 substance (not counted in the score)
Indicator2022202320242025PAHs (combustion and deposition)fluoranthene–site not in the yearbook·standard met·standard met●standard not metPolycyclic aromatic hydrocarbons. The standard for benzo(a)pyrene is extremely low (0.17 ng/l), so most streams exceed it; the main sources are combustion and atmospheric deposition.
Nearest site for the fishing districts: Hron č.10a, Hron č.10b, Hron č.11a
The location of the site is only approximate (based on the water body).
Banská BystricaBystrica, river km 2.10 indicators in 2025
Indicator2022202320242025Oxygen and organic mattertotal organic carbon·standard met●standard not met●standard not met·standard metNutrients and nitrogennitrites●standard not met·standard met·standard met·standard metHarmful organic substancesAOX (adsorbable organic halogens)·standard met·standard met●standard not met·standard metNearest site for the fishing districts: Bystrica (Ban. Bystrica)
The location of the site is only approximate (based on the water body).
Starý HrádokStará Podlužianka, river km 5.59 indicators in 2025
Indicator2022202320242025Oxygen and organic matterdissolved oxygen–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metNutrients and nitrogennitrates–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not mettotal phosphorus–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metSalts, pH and mineralspH–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metcalcium–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metPAHs: 4 substances (not counted in the score)
Indicator2022202320242025PAHs (combustion and deposition)benzo(a)pyrene–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metbenzo(b)fluoranthene–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metfluoranthene–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metperylene–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metPolycyclic aromatic hydrocarbons. The standard for benzo(a)pyrene is extremely low (0.17 ng/l), so most streams exceed it; the main sources are combustion and atmospheric deposition.
Veľký DvorMalianka, river km 6.34 indicators in 2025
Indicator2022202320242025Oxygen and organic matterCOD (chemical oxygen demand)–site not in the yearbook–site not in the yearbook·standard met●standard not metNutrients and nitrogennitrates–site not in the yearbook–site not in the yearbook·standard met●standard not mettotal nitrogen–site not in the yearbook–site not in the yearbook·standard met●standard not metSalts, pH and mineralsconductivity–site not in the yearbook–site not in the yearbook·standard met●standard not metNýrica, mouth, near Pohronský RuskovNýrica, river km 0.54 indicators in 2025
Indicator2022202320242025Nutrients and nitrogenammonium–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metnitrates–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not mettotal nitrogen–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not metSalts, pH and mineralsconductivity–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not met
- standard not met
- no unmet standard
- site not in the yearbook
Fishing districts near these sites
Fishing districts whose nearest SHMÚ site lies in this river basin
- Zolnásite Zolná, mouth · standard not met in 4 of 4 years · nitrates in the groundwater nearby 7.7 mg/l12 indicators
- VN Kalná n. Hronomsite Kalná nad Hronom · standard not met in 1 of 4 years · nitrates in the groundwater nearby 48.5 mg/l11 indicators
- Kremnický potoksite Kremnica, below · standard not met in 3 of 4 years · nitrates in the groundwater nearby 0.5 mg/l8 indicators
- Hron č. 1site Kamenica nad Hronom · standard not met in 4 of 4 years · nitrates in the groundwater nearby 55.3 mg/l5 indicators
- Hron č. 2site Kamenica nad Hronom · standard not met in 4 of 4 years · nitrates in the groundwater nearby 0.5 mg/l5 indicators
- Hron č.10asite Nemecká, bridge (PTCHEM, below) · standard not met in 3 of 4 years · nitrates in the groundwater nearby 4.5 mg/l3 indicators
- Hron č.10bsite Nemecká, bridge (PTCHEM, below) · standard not met in 3 of 4 years · nitrates in the groundwater nearby 8.0 mg/l3 indicators
- Hron č.11asite Nemecká, bridge (PTCHEM, below) · standard not met in 3 of 4 years · nitrates in the groundwater nearby 8.0 mg/l3 indicators
- Hučava (Zvolen)site Hučava, bridge (towards Zvolenská Slatina) · standard not met in 1 of 4 years · nitrates in the groundwater nearby 4.4 mg/l3 indicators
- Perec č. 1site Sikenička (Pavlová) · standard not met in 1 of 4 years · nitrates in the groundwater nearby 0.5 mg/l3 indicators
- Perec č. 2site Sikenička (Pavlová) · standard not met in 1 of 4 years · nitrates in the groundwater nearby 9.7 mg/l3 indicators
- Rohoznásite Rohozná pri Brezne (road bridge to Kozlovo) · standard not met in 1 of 4 years · nitrates in the groundwater nearby 6.4 mg/l3 indicators
- Tajovský potok č. 1site Banská Bystrica (indoor swimming pool, above) · standard not met in 1 of 4 years · nitrates in the groundwater nearby 3.2 mg/l3 indicators
- Hron č. 8site Dubová, bridge (PTCHEM, above) · standard not met in 3 of 4 years · nitrates in the groundwater nearby 5.1 mg/l2 indicators
- Hron č. 9asite Dubová, bridge (PTCHEM, above) · standard not met in 3 of 4 years · nitrates in the groundwater nearby 3.0 mg/l2 indicators
- Hron č. 9bsite Dubová, bridge (PTCHEM, above) · standard not met in 3 of 4 years · nitrates in the groundwater nearby 3.0 mg/l2 indicators
- Hron č. 9csite Dubová, bridge (PTCHEM, above) · standard not met in 3 of 4 years · nitrates in the groundwater nearby 1.5 mg/l2 indicators
- Bystrianka č. 1 (Štiavnička)site Valaská – Piesok part · standard not met in 1 of 4 years · nitrates in the groundwater nearby 4.4 mg/l2 indicators
- Bystrianka č. 2 (Trangoška)site Valaská – Piesok part · standard not met in 1 of 4 years · nitrates in the groundwater nearby 1.7 mg/l2 indicators
- Hron č.11bsite Závadka nad Hronom · standard not met in 1 of 4 years · nitrates in the groundwater nearby 28.2 mg/l2 indicators
- Hron č.12site Závadka nad Hronom · standard not met in 1 of 4 years · nitrates in the groundwater nearby 4.5 mg/l2 indicators
- Lukavicasite Lukavica, below · standard not met in 1 of 4 years · nitrates in the groundwater nearby 7.7 mg/l2 indicators
- Neresnicasite Breziny, below · standard not met in 1 of 4 years · nitrates in the groundwater nearby 4.1 mg/l2 indicators
- Sikenica č. 1site Horša · standard not met in 1 of 4 years · nitrates in the groundwater nearby 32.9 mg/l2 indicators
- Sikenica č. 2site Horša · standard not met in 1 of 4 years · nitrates in the groundwater nearby 9.7 mg/l2 indicators
- VN Tekovsite Nový Tekov, above · standard not met in 1 of 4 years · nitrates in the groundwater nearby 23.5 mg/l2 indicators
- VN Závadka nad Hronomsite Závadka nad Hronom · standard not met in 1 of 4 years · nitrates in the groundwater nearby 4.5 mg/l2 indicators
- Hron č. 6asite Žiar nad Hronom · standard not met in 4 of 4 years · nitrates in the groundwater nearby 0.5 mg/l1 indicator
- Hron č. 6bsite Žiar nad Hronom · standard not met in 4 of 4 years · nitrates in the groundwater nearby 0.5 mg/l1 indicator
- Vajskovský potoksite Vajskovský potok, mouth · standard not met in 4 of 4 years · nitrates in the groundwater nearby 1.5 mg/l1 indicator
- Lutilský potoksite Žiar nad Hronom – cottage area (footbridge over the stream) · standard not met in 2 of 4 years · nitrates in the groundwater nearby 0.5 mg/l1 indicator
- Slatina č. 1site VN Môťová, above · standard not met in 2 of 4 years · nitrates in the groundwater nearby 5.1 mg/l1 indicator
- VN Môťovásite VN Môťová, above · standard not met in 2 of 4 years · nitrates in the groundwater nearby 20.1 mg/l1 indicator
- VN Voznicasite Voznica, above · standard not met in 2 of 4 years1 indicator
- Brusniankasite Brusnianka, Brusno Spa, above · standard not met in 1 of 4 years · nitrates in the groundwater nearby 4.5 mg/l1 indicator
- Hron č. 5site Žarnovica, above · standard not met in 1 of 4 years · nitrates in the groundwater nearby 3.4 mg/l1 indicator
- Kľaksite Žarnovická Huta · standard not met in 1 of 4 years · nitrates in the groundwater nearby 4.1 mg/l1 indicator
- Moštenický potok č.1site Moštenica, above · standard not met in 1 of 4 years · nitrates in the groundwater nearby 3.6 mg/l1 indicator
- Pokutský potoksite Žliabok v Hlbokej doline, below · standard not met in 1 of 4 years · nitrates in the groundwater nearby 4.1 mg/l1 indicator
- Prochotský potoksite Horná Ždaňa, above (forester's lodge) · standard not met in 1 of 4 years · nitrates in the groundwater nearby 4.1 mg/l1 indicator
Showing 40 of 55 fishing districts, worst first.
What most often fails
Number of sites in the river basin that failed this indicator in 2025
- counted in the fishing district score
- shown, not counted in the score
Where the data come from and what they do not say
- Surface waters: yearbooks of the Slovak Hydrometeorological Institute (SHMÚ) Surface Water Quality for the years 2022 to 2025. We transcribed the list of sites and indicators that failed the standard under Government Regulation no. 269/2010 Coll. into a table in the plugin. Older yearbooks are in a different format and we did not include them.
- Groundwater: SHMÚ yearbooks Groundwater Quality, stations and indicators exceeded in 2017 to 2025 according to the drinking-water limits. The connection to the fishing district is only indirect.
- Groundwater, measured values: the public SHMÚ interface "Groundwater quality monitoring results". We have actually measured values (nitrates, ammonium, iron, chlorides, metals, pesticides, PFAS, solvents) for 758 stations; for each substance we take the highest value from the samples in 2025 (for stations without data for that year, from one of the two previous years). A value equal to the standard counts as an exceedance, as it does at SHMÚ.
- Treatment plants: register of wastewater treatment plants (VÚVH, EEA) from the "Points near fishing districts" file, that is, only plants within 2 km of the fishing district line. There are considerably more treatment plants in Slovakia.
What this data does not say. The yearbook lists the sites that failed the standard. A site missing from it is not proof of clean water, so the score of a fishing district is only ever lowered and never raised. We did not include industrial polluters (the National Pollution Register) in the list because the register was unavailable when the data was collected, and for wastewater treatment plants we list only those we found near the fishing districts. Only 31% of SHMÚ sites have an exact location, 47% have only an approximate location (based on the water body, so they count less near the districts) and 22% have no location at all, so we do not assign them to any district. We determine the distance, the match of the watercourse name and the ranking ourselves; the assignment is indicative.