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River basin

Water pollution in the Hornád basin

Sites in the 2025 yearbook
20
Failed the standard (85%)
17
Counted in the score
17

River basin overview

In the Hornád basin the SHMÚ yearbook has 20 monitoring sites; in 2025, 17 of them (85%) failed the standard for at least one indicator. 17 are counted in the scores of the fishing districts.

Watercourse profile of Hornád

SHMÚ sites from source to mouth

Watercourse profile from source to mouthnumber of unmet indicators in 2025 at SHMÚ sites

012345Bystrá, above, river km 165.2: no failed standard (2024)Hranovnica, river km 159.4: 3 indicators (2025)Klčovský potok, below the tributary, river km 106.7: 1 indicator (2023)SEZ Krompachy, below, river km 96.4: no failed standard (2024)Kluknava, below, river km 92.1: 1 indicator (2025)Kluknava, below (Štefanská Huta), river km 90.0: 1 indicator (2023)ÚKČ Košice, below, river km 23.5: no failed standard (2024)Ždaňa, river km 17.0: 1 indicator (2023)Hidasnémeti, river km 0.0: 5 indicators (2025)river km 165 (upper course)river km 0 (towards the mouth)
Show sites in the table (9)
  • Bystrá, aboveriver km 165.2no unmet standard
  • Hranovnicariver km 159.43 indicators
  • Klčovský potok, below the tributaryriver km 106.71 indicator
  • SEZ Krompachy, belowriver km 96.4no unmet standard
  • Kluknava, belowriver km 92.11 indicator
  • Kluknava, below (Štefanská Huta)river km 90.01 indicator
  • ÚKČ Košice, belowriver km 23.5no unmet standard
  • Ždaňariver km 17.01 indicator
  • Hidasnémetiriver km 0.05 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
  1. 202224 of 2596%
  2. 202324 of 2789%
  3. 202425 of 3669%
  4. 202517 of 2085%

Fishing district map

Fishing districts of the “Bodrog and Hornád basin” by the nearest SHMÚ site

Detailed filtersregion, district, riverbed, depth, shading, satellites, water chemistry and pollution, fish, geology

1445fishing districts
Pick a category to narrow the selection. Next to each option you can see how many fishing districts remain.
Map color
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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 yearFailed a standard17 / 20
  1. HidasnémetiHornád, river km 0.05 indicators in 2025
    Indicator2022202320242025
    Oxygen and organic matter
    COD (chemical oxygen demand)●standard not met●standard not met●standard not met·standard met
    Nutrients and nitrogen
    nitrites●standard not met●standard not met●standard not met●standard not met
    total phosphorus·standard met·standard met●standard not met·standard met
    Harmful organic substances
    AOX (adsorbable organic halogens)●standard not met●standard not met●standard not met·standard met
    Biology and bacteria
    coliform bacteria●standard not met●standard not met●standard not met●standard not met
    culturable microorganisms (22 °C)●standard not met●standard not met●standard not met●standard not met
    thermotolerant coliform bacteria●standard not met●standard not met●standard not met●standard not met
    intestinal enterococci●standard not met●standard not met●standard not met●standard not met
    saprobic index of biosestone·standard met●standard not met·standard met·standard met

    Nearest site for the fishing districts: Hornád č. 1a

    The location of the site is only approximate (based on the water body).

  2. TornyosnémetiSokoliansky P., river km 0.012 indicators in 2025
    Indicator2022202320242025
    Nutrients and nitrogen
    nitrites●standard not met●standard not met·standard met●standard not met
    nitrates●standard not met●standard not met·standard met·standard met
    Harmful organic substances
    AOX (adsorbable organic halogens)●standard not met●standard not met●standard not met●standard not met
    total cyanides●standard not met●standard not met●standard not met●standard not met
    PFOS (perfluorooctane sulfonate)·standard met·standard met·standard met●standard not met
    Salts, pH and minerals
    fluorides●standard not met●standard not met●standard not met●standard not met
    conductivity●standard not met●standard not met●standard not met●standard not met
    Biology and bacteria
    coliform bacteria●standard not met●standard not met●standard not met●standard not met
    culturable microorganisms (22 °C)●standard not met●standard not met●standard not met●standard not met
    thermotolerant coliform bacteria●standard not met●standard not met●standard not met●standard not met
    intestinal enterococci●standard not met●standard not met●standard not met●standard not met
    saprobic index of biosestone·standard met●standard not met·standard met·standard met
    PAHs: 2 substances (not counted in the score)
    Indicator2022202320242025
    PAHs (combustion and deposition)
    benzo(a)pyrene●standard not met·standard met●standard not met●standard not met
    fluoranthene●standard not met·standard met·standard met●standard not met

    Polycyclic 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).

  3. HranovnicaHornád, river km 159.43 indicators in 2025
    Indicator2022202320242025
    Oxygen and organic matter
    COD (chemical oxygen demand)●standard not met·standard met·standard met●standard not met
    Nutrients and nitrogen
    nitrites●standard not met●standard not met●standard not met●standard not met
    total phosphorus·standard met·standard met·standard met●standard not met
    Harmful organic substances
    AOX (adsorbable organic halogens)●standard not met·standard met·standard met·standard met
    petroleum substances (NEL)●standard not met·standard met·standard met·standard met
    Biology and bacteria
    saprobic index of biosestone·standard met●standard not met·standard met·standard met

    The location of the site is only approximate (based on the water body).

  4. Šalgovický potok, belowSekčov, river km 2.02 indicators in 2025
    Indicator2022202320242025
    Oxygen and organic matter
    COD (chemical oxygen demand)·standard met●standard not met·standard met·standard met
    Nutrients and nitrogen
    nitrites●standard not met●standard not met●standard not met●standard not met
    Harmful organic substances
    petroleum substances (NEL)●standard not met·standard met·standard met●standard not met
    AOX (adsorbable organic halogens)●standard not met·standard met·standard met·standard met
    Biology and bacteria
    saprobic index of biosestone·standard met●standard not met·standard met·standard met

    Nearest site for the fishing districts: Sekčov č. 1

    The location of the site is only approximate (based on the water body).

  5. Košické OlšanyTorysa, river km 13.02 indicators in 2025
    Indicator2022202320242025
    Oxygen and organic matter
    COD (chemical oxygen demand)·standard met●standard not met●standard not met·standard met
    Nutrients and nitrogen
    nitrites●standard not met●standard not met●standard not met●standard not met
    Harmful organic substances
    AOX (adsorbable organic halogens)●standard not met●standard not met·standard met·standard met
    Salts, pH and minerals
    calcium●standard not met·standard met·standard met·standard met
    PAHs: 1 substance (not counted in the score)
    Indicator2022202320242025
    PAHs (combustion and deposition)
    benzo(a)pyrene·standard met·standard met·standard met●standard not met

    Polycyclic 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: Torysa č. 1

    The location of the site is only approximate (based on the water body).

  6. DrienovDrienovský potok, river km 0.57 indicators in 2025
    Indicator2022202320242025
    Oxygen and organic matter
    BOD₅ (biochemical oxygen demand)–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not met
    COD (chemical oxygen demand)–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not met
    Nutrients and nitrogen
    ammonium–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not met
    nitrites–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not met
    nitrates–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not met
    total nitrogen–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not met
    total phosphorus–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not met
  7. Ružin Reservoir, inflowHnilec, river km 4.12 indicators in 2025
    Indicator2022202320242025
    Nutrients and nitrogen
    nitrites●standard not met●standard not met●standard not met●standard not met
    Harmful organic substances
    AOX (adsorbable organic halogens)●standard not met●standard not met·standard met·standard met
    petroleum substances (NEL)●standard not met·standard met·standard met·standard met
    PAHs: 1 substance (not counted in the score)
    Indicator2022202320242025
    PAHs (combustion and deposition)
    benzo(a)pyrene·standard met●standard not met●standard not met●standard not met

    Polycyclic 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: Hnilec č. 1, Hnilec č. 2, Hnilec č. 3, VN Ružín

    The location of the site is only approximate (based on the water body).

  8. Veľký Šariš, mouthŠarišský potok, river km 0.17 indicators in 2024
    Indicator2022202320242025
    Oxygen and organic matter
    COD (chemical oxygen demand)–site not in the yearbook–site not in the yearbook●standard not met–site not in the yearbook
    dissolved oxygen–site not in the yearbook–site not in the yearbook●standard not met–site not in the yearbook
    Nutrients and nitrogen
    ammonium–site not in the yearbook–site not in the yearbook●standard not met–site not in the yearbook
    nitrites–site not in the yearbook–site not in the yearbook●standard not met–site not in the yearbook
    total nitrogen–site not in the yearbook–site not in the yearbook●standard not met–site not in the yearbook
    total phosphorus–site not in the yearbook–site not in the yearbook●standard not met–site not in the yearbook
    Salts, pH and minerals
    conductivity–site not in the yearbook–site not in the yearbook●standard not met–site not in the yearbook
  9. ObišovceSvinka, river km 2.04 indicators in 2025
    Indicator2022202320242025
    Oxygen and organic matter
    COD (chemical oxygen demand)–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not met
    dissolved oxygen–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not met
    Nutrients and nitrogen
    nitrites–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not met
    PAHs: 1 substance (not counted in the score)
    Indicator2022202320242025
    PAHs (combustion and deposition)
    benzo(a)pyrene–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not met

    Polycyclic 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.

  10. Nižná HutkaTorysa, river km 1.03 indicators in 2025
    Indicator2022202320242025
    Oxygen and organic matter
    BOD₅ (biochemical oxygen demand)–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not met
    COD (chemical oxygen demand)–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not met
    Nutrients and nitrogen
    nitrites–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not met

    The location of the site is only approximate (based on the water body).

  11. Smolník, mouthSmolník, river km 0.41 indicator in 2025
    Indicator2022202320242025
    Nutrients and nitrogen
    nitrites●standard not met·standard met·standard met·standard met
    Metals
    zinc●standard not met●standard not met●standard not met●standard not met
    PAHs: 1 substance (not counted in the score)
    Indicator2022202320242025
    PAHs (combustion and deposition)
    benzo(a)pyrene●standard not met·standard met●standard not met·standard met

    Polycyclic 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.

  12. Stará Voda, mouthStará Voda, river km 0.12 indicators in 2025
    Indicator2022202320242025
    Nutrients and nitrogen
    nitrites–site not in the yearbook●standard not met–site not in the yearbook●standard not met
    Metals
    copper–site not in the yearbook·standard met–site not in the yearbook●standard not met

    Nearest site for the fishing districts: Stará Voda

    The location of the site is only approximate (based on the water body).

  13. Kluknava, belowHornád, river km 92.11 indicator in 2025
    Indicator2022202320242025
    Nutrients and nitrogen
    nitrites●standard not met–site not in the yearbook●standard not met●standard not met
    Harmful organic substances
    AOX (adsorbable organic halogens)●standard not met–site not in the yearbook·standard met·standard met
    petroleum substances (NEL)●standard not met–site not in the yearbook·standard met·standard met
    Biology and bacteria
    saprobic index of biosestone●standard not met–site not in the yearbook·standard met·standard met
    PAHs: 2 substances (not counted in the score)
    Indicator2022202320242025
    PAHs (combustion and deposition)
    benzo(a)pyrene●standard not met–site not in the yearbook●standard not met·standard met
    fluoranthene·standard met–site not in the yearbook●standard not met·standard met

    Polycyclic 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).

  14. Veľký Šariš, aboveDzikov, river km 2.43 indicators in 2024
    Indicator2022202320242025
    Oxygen and organic matter
    COD (chemical oxygen demand)–site not in the yearbook–site not in the yearbook●standard not met–site not in the yearbook
    Nutrients and nitrogen
    nitrites–site not in the yearbook–site not in the yearbook●standard not met–site not in the yearbook
    total phosphorus–site not in the yearbook–site not in the yearbook●standard not met–site not in the yearbook

    Nearest site for the fishing districts: Dzikov, Štrkovisko Veľký Šariš č. 1, Štrkovisko Veľký Šariš č. 2, Štrkovisko Veľký Šariš č. 3 and more (1)

  15. Herliansky P., mouthHerliansky P., river km 0.32 indicators in 2025
    Indicator2022202320242025
    Oxygen and organic matter
    dissolved oxygen–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not met
    Nutrients and nitrogen
    nitrites–site not in the yearbook–site not in the yearbook–site not in the yearbook●standard not met
  16. Slavkovský P., mouthSlavkovský P., river km 0.00 indicators in 2025
    Indicator2022202320242025
    Oxygen and organic matter
    COD (chemical oxygen demand)●standard not met·standard met·standard met·standard met
    Nutrients and nitrogen
    nitrites●standard not met●standard not met●standard not met·standard met

    Nearest site for the fishing districts: Slavkovský potok (Sabinov)

  17. KendiceTorysa, river km 49.90 indicators in 2024
    Indicator2022202320242025
    Oxygen and organic matter
    COD (chemical oxygen demand)·standard met●standard not met·standard met–site not in the yearbook
    Nutrients and nitrogen
    nitrites●standard not met●standard not met·standard met–site not in the yearbook
    Harmful organic substances
    AOX (adsorbable organic halogens)●standard not met·standard met·standard met–site not in the yearbook
    petroleum substances (NEL)●standard not met·standard met·standard met–site not in the yearbook
    Biology and bacteria
    saprobic index of biosestone●standard not met·standard met·standard met–site not in the yearbook

    The location of the site is only approximate (based on the water body).

  18. Spišská Nová VesBrusník, river km 1.08 indicators in 2023
    Indicator2022202320242025
    Oxygen and organic matter
    COD (chemical oxygen demand)–site not in the yearbook●standard not met–site not in the yearbook–site not in the yearbook
    Nutrients and nitrogen
    ammonium–site not in the yearbook●standard not met–site not in the yearbook–site not in the yearbook
    nitrites–site not in the yearbook●standard not met–site not in the yearbook–site not in the yearbook
    total phosphorus–site not in the yearbook●standard not met–site not in the yearbook–site not in the yearbook
    Salts, pH and minerals
    conductivity–site not in the yearbook●standard not met–site not in the yearbook–site not in the yearbook
    calcium–site not in the yearbook●standard not met–site not in the yearbook–site not in the yearbook
    PAHs: 2 substances (not counted in the score)
    Indicator2022202320242025
    PAHs (combustion and deposition)
    benzo(a)pyrene–site not in the yearbook●standard not met–site not in the yearbook–site not in the yearbook
    fluoranthene–site not in the yearbook●standard not met–site not in the yearbook–site not in the yearbook

    Polycyclic 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.

  19. Veľký Šariš, mouthVeľký potok, river km 0.12 indicators in 2024
    Indicator2022202320242025
    Oxygen and organic matter
    COD (chemical oxygen demand)–site not in the yearbook–site not in the yearbook●standard not met–site not in the yearbook
    Nutrients and nitrogen
    nitrites–site not in the yearbook–site not in the yearbook●standard not met–site not in the yearbook
  20. Kluknava, below (Štefanská Huta)Hornád, river km 90.01 indicator in 2023
    Indicator2022202320242025
    Nutrients and nitrogen
    nitrites●standard not met●standard not met–site not in the yearbook–site not in the yearbook
    Harmful organic substances
    AOX (adsorbable organic halogens)●standard not met·standard met–site not in the yearbook–site not in the yearbook
    Biology and bacteria
    saprobic index of biosestone●standard not met·standard met–site not in the yearbook–site not in the yearbook

    The location of the site is only approximate (based on the water body).

  • 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
  • Hornád č. 1asite Hidasnémeti · standard not met in 4 of 4 years · nitrates in the groundwater nearby 1.1 mg/l5 indicators
  • Štrkovisko Kechnecsite Kechnec, behind the railway station · standard not met in 1 of 4 years · nitrates in the groundwater nearby 19.0 mg/l4 indicators
  • Dzikovsite Veľký Šariš, above · standard not met in 1 of 4 years · nitrates in the groundwater nearby 36.2 mg/l3 indicators
  • Malá Svinkasite Svinia · standard not met in 1 of 4 years · nitrates in the groundwater nearby 19.8 mg/l3 indicators
  • Sekčov č. 2site Fulianka · standard not met in 1 of 4 years · nitrates in the groundwater nearby 8.1 mg/l3 indicators
  • Štrkovisko Veľký Šariš č. 1site Veľký Šariš, above · standard not met in 1 of 4 years · nitrates in the groundwater nearby 36.2 mg/l3 indicators
  • Štrkovisko Veľký Šariš č. 2site Veľký Šariš, above · standard not met in 1 of 4 years · nitrates in the groundwater nearby 36.2 mg/l3 indicators
  • Štrkovisko Veľký Šariš č. 3site Veľký Šariš, above · standard not met in 1 of 4 years · nitrates in the groundwater nearby 36.2 mg/l3 indicators
  • Štrkovisko Veľký Šariš č. 4site Veľký Šariš, above · standard not met in 1 of 4 years · nitrates in the groundwater nearby 36.2 mg/l3 indicators
  • Hnilec č. 1site Ružin Reservoir, inflow · standard not met in 4 of 4 years · nitrates in the groundwater nearby 2.5 mg/l2 indicators
  • Hnilec č. 2site Ružin Reservoir, inflow · standard not met in 4 of 4 years · nitrates in the groundwater nearby 43.7 mg/l2 indicators
  • Hnilec č. 3site Ružin Reservoir, inflow · standard not met in 4 of 4 years · nitrates in the groundwater nearby 43.7 mg/l2 indicators
  • Sekčov č. 1site Šalgovický potok, below · standard not met in 4 of 4 years · nitrates in the groundwater nearby 40.2 mg/l2 indicators
  • Torysa č. 1site Košické Olšany · standard not met in 4 of 4 years · nitrates in the groundwater nearby 2.3 mg/l2 indicators
  • VN Ružínsite Ružin Reservoir, inflow · standard not met in 4 of 4 years · nitrates in the groundwater nearby 4.5 mg/l2 indicators
  • Stará Vodasite Stará Voda, mouth · standard not met in 2 of 4 years · nitrates in the groundwater nearby 3.9 mg/l2 indicators
  • Jakuboviansky potoksite Sabinov · standard not met in 1 of 4 years · nitrates in the groundwater nearby 7.6 mg/l2 indicators
  • Torysa č. 2asite Šarišské Michaľany · standard not met in 1 of 4 years · nitrates in the groundwater nearby 36.2 mg/l2 indicators
  • Torysa č. 3site Šarišské Michaľany · standard not met in 1 of 4 years · nitrates in the groundwater nearby 36.2 mg/l2 indicators
  • Torysa č. 4site Šarišské Michaľany · standard not met in 1 of 4 years · nitrates in the groundwater nearby 19.8 mg/l2 indicators
  • Torysa č. 5site Torysa, intake structure Tichý potok, above · standard not met in 1 of 4 years · nitrates in the groundwater nearby 10.1 mg/l2 indicators
  • Torysa č. 6site Torysa, intake structure Tichý potok, above · standard not met in 1 of 4 years · nitrates in the groundwater nearby 10.1 mg/l2 indicators
  • Torysa č. 7site Torysa, intake structure Tichý potok, above · standard not met in 1 of 4 years · nitrates in the groundwater nearby 10.1 mg/l2 indicators
  • Torysa č. 8site Torysa, intake structure Tichý potok, above · standard not met in 1 of 4 years · nitrates in the groundwater nearby 1.4 mg/l2 indicators
  • Gánovský potok č. 1site Gánovský potok, mouth · standard not met in 1 of 4 years · nitrates in the groundwater nearby 0.5 mg/l1 indicator
  • Hornád č. 1bsite Ždaňa · standard not met in 1 of 4 years · nitrates in the groundwater nearby 10.0 mg/l1 indicator
  • Hornád č. 4site Klčovský potok, below the tributary · standard not met in 1 of 4 years · nitrates in the groundwater nearby 24.3 mg/l1 indicator
  • Hornád č. 5asite Klčovský potok, below the tributary · standard not met in 1 of 4 years · nitrates in the groundwater nearby 2.8 mg/l1 indicator
  • Torysa č. 2site Prešov, above VK · standard not met in 1 of 4 years · nitrates in the groundwater nearby 13.5 mg/l1 indicator
  • Torysa č.2asite Prešov, above VK · standard not met in 1 of 4 years · nitrates in the groundwater nearby 40.2 mg/l1 indicator
  • Ľutinka č.1site Majdan, above · standard not met in 1 of 4 years · nitrates in the groundwater nearby 19.8 mg/l1 indicator
  • Slavkovský potok (Sabinov)site Slavkovský P., mouth · standard not met in 3 of 4 years · nitrates in the groundwater nearby 10.1 mg/lno unmet standard
  • Lipiansky potoksite Lipany · standard not met in 1 of 4 years · nitrates in the groundwater nearby 19.8 mg/lno unmet standard
  • Veľká Biela Voda (NP Slovak Paradise)site Podlesok · standard not met in 1 of 4 years · nitrates in the groundwater nearby 7.3 mg/lno unmet standard
  • Hnilec č. 4site ŽST Vernár, above · standard not met in 0 of 4 years · nitrates in the groundwater nearby 6.4 mg/lno unmet standard
  • Hornád č. 2asite ÚKČ Košice, below · standard not met in 0 of 4 years · nitrates in the groundwater nearby 9.1 mg/lno unmet standard
  • Hornád č. 2bsite ÚKČ Košice, below · standard not met in 0 of 4 years · nitrates in the groundwater nearby 9.1 mg/lno unmet standard
  • Hornád č. 2csite ÚKČ Košice, below · standard not met in 0 of 4 years · nitrates in the groundwater nearby 4.5 mg/lno unmet standard
  • Hornád č. 3site ÚKČ Košice, below · standard not met in 0 of 4 years · nitrates in the groundwater nearby 24.3 mg/lno unmet standard
  • Hornád č. 5bsite Bystrá, above · standard not met in 0 of 4 years · nitrates in the groundwater nearby 2.8 mg/lno unmet standard

Showing 40 of 48 fishing districts, worst first.

What most often fails

Number of sites in the river basin that failed this indicator in 2025
  1. nitritesNutrients and nitrogen16
  2. benzo(a)pyrenePAHs (combustion and deposition)5
  3. COD (chemical oxygen demand)Oxygen and organic matter4
  4. total phosphorusNutrients and nitrogen2
  5. dissolved oxygenOxygen and organic matter2
  6. conductivitySalts, pH and minerals2
  7. BOD₅ (biochemical oxygen demand)Oxygen and organic matter2
  8. coliform bacteriaBiology and bacteria2
  9. thermotolerant coliform bacteriaBiology and bacteria2
  10. intestinal enterococciBiology and bacteria2
  11. culturable microorganisms (22 °C)Biology and bacteria2
  12. copperMetals1
  • 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.