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River basin

Water pollution in the Ipeľ basin

Sites in the 2025 yearbook
24
Failed the standard (67%)
16
Counted in the score
10

River basin overview

In the Ipeľ basin the SHMÚ yearbook has 24 monitoring sites; in 2025, 16 of them (67%) failed the standard for at least one indicator. 10 are counted in the scores of the fishing districts.

Watercourse profile of Ipeľ

SHMÚ sites from source to mouth

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

012345VN Málinec, above, river km 197.6: 2 indicators (2025)bridge Bystrička – Hrabovská, river km 187.8: no failed standard (2025)Breznička (below Banský potok), river km 176.4: 2 indicators (2025)Kalonda, river km 144.5: 3 indicators (2025)Vrbovka, river km 106.2: 2 indicators (2023)Kubáňovo, river km 38.3: no failed standard (2025)Salka, river km 12.0: 5 indicators (2025)river km 198 (upper course)river km 12 (towards the mouth)
Show sites in the table (7)
  • VN Málinec, aboveriver km 197.62 indicators
  • bridge Bystrička – Hrabovskáriver km 187.8no unmet standard
  • Breznička (below Banský potok)river km 176.42 indicators
  • Kalondariver km 144.53 indicators
  • Vrbovkariver km 106.22 indicators
  • Kubáňovoriver km 38.3no unmet standard
  • Salkariver km 12.05 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. 202227 of 3187%
  2. 202320 of 2291%
  3. 202424 of 3177%
  4. 202516 of 2467%

Fishing district map

Fishing districts in the “Danube river basin” by 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.
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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

  1. PršaSuchá, river km 3.14 indicators in 2025
    Indicator2022202320242025
    Oxygen and organic matter
    total organic carbon●standard not met●standard not met●standard not met·standard met
    dissolved oxygen●standard not met·standard met●standard not met●standard not met
    Nutrients and nitrogen
    total phosphorus●standard not met●standard not met●standard not met●standard not met
    nitrites●standard not met●standard not met·standard met·standard met
    ammonium●standard not met·standard met·standard met·standard met
    Metals
    nickel●standard not met·standard met·standard met·standard met
    Harmful organic substances
    AOX (adsorbable organic halogens)●standard not met●standard not met●standard not met●standard not met
    Salts, pH and minerals
    calcium●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 not met·standard 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).

  2. KalondaIpeľ, river km 144.53 indicators in 2025
    Indicator2022202320242025
    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 not met●standard not met
  3. Štiavnica, mouthŠtiavnica, river km 1.12 indicators in 2025
    Indicator2022202320242025
    Oxygen and organic matter
    total organic carbon·standard met●standard not met●standard not met·standard met
    Nutrients and nitrogen
    nitrites●standard not met●standard not met·standard met·standard met
    Harmful organic substances
    AOX (adsorbable organic halogens)·standard met●standard not met●standard not met●standard not met
    Biology and bacteria
    saprobic index of biosestone·standard met●standard not 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 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: Štiavnica č. 1 (Šahy)

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

  4. Šahy, above (road bridge Šahy – Hrkovce)Krupinica, river km 1.12 indicators in 2025
    Indicator2022202320242025
    Oxygen and organic matter
    total organic carbon·standard met●standard not met●standard not met·standard met
    Nutrients and nitrogen
    nitrites●standard not met●standard not met·standard met·standard met
    Harmful organic substances
    AOX (adsorbable organic halogens)·standard 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 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: Krupinica č. 1, Štrkovisko Šahy

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

  5. SalkaIpeľ, river km 12.05 indicators in 2025
    Indicator2022202320242025
    Nutrients and nitrogen
    nitrites●standard not met●standard not met●standard not met●standard not met
    total phosphorus●standard not met·standard met·standard met·standard met
    Harmful organic substances
    AOX (adsorbable organic halogens)·standard met·standard met·standard met●standard not met
    PFOS (perfluorooctane sulfonate)·standard met·standard met·standard met●standard not met
    Biology and bacteria
    culturable microorganisms (22 °C)●standard not met●standard not met●standard not met●standard not met
    intestinal enterococci·standard met●standard not met●standard not met·standard met
    chlorophyll a●standard not met·standard met·standard met·standard met
    thermotolerant coliform bacteria·standard met·standard met●standard not 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: Ipeľ č. 1

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

  6. TrebeľovceBabský potok, river km 1.36 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
    total organic carbon–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
    total phosphorus–site not in the yearbook–site not in the yearbook●standard not met–site not in the yearbook
    Salts, pH and minerals
    calcium–site not in the yearbook–site not in the yearbook●standard not met–site not in the yearbook
    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●standard not met–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.

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

  7. Stracinský potok, mouthStracinský potok, river km 1.13 indicators in 2025
    Indicator2022202320242025
    Oxygen and organic matter
    COD (chemical oxygen demand)●standard not met–site not in the yearbook·standard met·standard met
    total organic carbon●standard not met–site not in the yearbook·standard met·standard met
    dissolved oxygen●standard not met–site not in the yearbook·standard met·standard met
    Nutrients and nitrogen
    total phosphorus●standard not met–site not in the yearbook●standard not met●standard not met
    nitrates●standard not met–site not in the yearbook·standard met●standard not met
    ammonium●standard not met–site not in the yearbook·standard met·standard met
    nitrites●standard not met–site not in the yearbook·standard met·standard met
    total nitrogen●standard not met–site not in the yearbook·standard met·standard met
    Salts, pH and minerals
    conductivity●standard not met–site not in the yearbook·standard met●standard not met
    calcium●standard not met–site not in the yearbook·standard met·standard met
  8. VN Málinec, aboveIpeľ, river km 197.62 indicators in 2025
    Indicator2022202320242025
    Harmful organic substances
    AOX (adsorbable organic halogens)·standard met●standard not met●standard not met●standard not met
    Biology and bacteria
    saprobic index of biosestone●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.

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

  9. Slatinka, road bridge Lučenec – Boľkovce, aboveSlatinka, river km 4.04 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
    total organic carbon–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
    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●standard not met–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.

  10. Opatovská Nová Ves, belowČebovský potok, river km 2.66 indicators in 2023
    Indicator2022202320242025
    Oxygen and organic matter
    total organic carbon–site not in the yearbook●standard not met–site not in the yearbook–site not in the yearbook
    dissolved oxygen–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
    total phosphorus–site not in the yearbook●standard not met–site not in the yearbook–site not in the yearbook
    Salts, pH and minerals
    calcium–site not in the yearbook●standard not met–site not in the yearbook–site not in the yearbook
    PAHs: 1 substance (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

    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.

  11. Selce, below (Hrnčiarska Ves, above)Selčiansky potok, river km 4.13 indicators in 2024
    Indicator2022202320242025
    Oxygen and organic matter
    total organic carbon–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
    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●standard not met–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.

  12. Dolná Telka (below Halič, above the Ľadovo Reservoir)Tuhársky potok, river km 6.53 indicators in 2024
    Indicator2022202320242025
    Oxygen and organic matter
    total organic carbon–site not in the yearbook–site not in the yearbook●standard not met–site not in the yearbook
    Nutrients and nitrogen
    total phosphorus–site not in the yearbook–site not in the yearbook●standard not met–site not in the yearbook
    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●standard not met–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.

    Nearest site for the fishing districts: VN Ľadovo

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

  13. Záhorský potok, belowKrtíš, river km 2.32 indicators in 2024
    Indicator2022202320242025
    Oxygen and organic matter
    total organic carbon·standard met–site not in the yearbook●standard not met–site not in the yearbook
    dissolved oxygen●standard not met–site not in the yearbook·standard met–site not in the yearbook
    Nutrients and nitrogen
    nitrites●standard not met–site not in the yearbook·standard met–site not in the yearbook
    total phosphorus●standard not met–site not in the yearbook·standard met–site not in the yearbook
    PAHs: 1 substance (not counted in the score)
    Indicator2022202320242025
    PAHs (combustion and deposition)
    benzo(a)pyrene●standard not met–site not in the yearbook●standard not met–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.

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

  14. Domaníky, belowŠtiavnica, river km 22.52 indicators in 2025
    Indicator2022202320242025
    Metals
    zinc–site not in the yearbook●standard not met–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·standard met–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.

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

  15. Uňatín, bridge – upper end of the villageČekovský potok, river km 3.29 indicators in 2022
    Indicator2022202320242025
    Oxygen and organic matter
    BOD₅ (biochemical oxygen demand)●standard not met–site not in the yearbook–site not in the yearbook–site not in the yearbook
    COD (chemical oxygen demand)●standard not met–site not in the yearbook–site not in the yearbook–site not in the yearbook
    total organic carbon●standard not met–site not in the yearbook–site not in the yearbook–site not in the yearbook
    Nutrients and nitrogen
    ammonium●standard not met–site not in the yearbook–site not in the yearbook–site not in the yearbook
    nitrites●standard not met–site not in the yearbook–site not in the yearbook–site not in the yearbook
    nitrates●standard not met–site not in the yearbook–site not in the yearbook–site not in the yearbook
    total nitrogen●standard not met–site not in the yearbook–site not in the yearbook–site not in the yearbook
    total phosphorus●standard not met–site not in the yearbook–site not in the yearbook–site not in the yearbook
    PAHs: 1 substance (not counted in the score)
    Indicator2022202320242025
    PAHs (combustion and deposition)
    benzo(a)pyrene●standard not met–site not in the yearbook–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.

  16. Stará Halič, aboveTuhársky potok, river km 12.60 indicators in 2025
    Indicator2022202320242025
    Oxygen and organic matter
    total organic carbon·standard met●standard not met·standard met·standard met
    Harmful organic substances
    AOX (adsorbable organic halogens)·standard met·standard met●standard not met·standard met

    Nearest site for the fishing districts: Tuhársky potok

  17. Lučenec, belowKrivánsky potok, river km 4.20 indicators in 2025
    Indicator2022202320242025
    Nutrients and nitrogen
    nitrites·standard met●standard not met–site not in the yearbook·standard met
    nitrates●standard not met·standard met–site not in the yearbook·standard met
    total phosphorus●standard not met·standard met–site not in the yearbook·standard met
    Biology and bacteria
    saprobic index of biosestone·standard met●standard not met–site not in the yearbook·standard met

    Nearest site for the fishing districts: Krivánsky potok

  18. BrezničkaBanský potok, river km 1.83 indicators in 2023
    Indicator2022202320242025
    Oxygen and organic matter
    total organic carbon–site not in the yearbook●standard not met–site not in the yearbook–site not in the yearbook
    Harmful organic substances
    octylphenol–site not in the yearbook●standard not met–site not in the yearbook–site not in the yearbook
    PAHs: 1 substance (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

    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: Banský potok

  19. Šipice, aboveBelujský potok, river km 2.03 indicators in 2023
    Indicator2022202320242025
    Oxygen and organic matter
    total organic carbon–site not in the yearbook●standard not met–site not in the yearbook–site not in the yearbook
    Nutrients and nitrogen
    total phosphorus–site not in the yearbook●standard not met–site not in the yearbook–site not in the yearbook
    PAHs: 1 substance (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

    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: Belujský potok

  20. Breznička (below Banský potok)Ipeľ, river km 176.42 indicators in 2025
    Indicator2022202320242025
    Metals
    lead–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.

    Nearest site for the fishing districts: Ipeľ č. 6, Ipeľ č. 7

  • 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

  • Štiavnica č. 3 (Ban. Štiavnica)site Svätý Anton, above · standard not met in 1 of 4 years · nitrates in the groundwater nearby 0.5 mg/l6 indicators
  • Ipeľ č. 1site Salka · standard not met in 4 of 4 years · nitrates in the groundwater nearby 54.1 mg/l5 indicators
  • Štrkovisko Rapovcesite Mučínsky potok, cestný most Rapovce – Trebeľovce · standard not met in 1 of 4 years5 indicators
  • Banský potoksite Breznička · standard not met in 1 of 4 years · nitrates in the groundwater nearby 2.4 mg/l3 indicators
  • Belujský potoksite Šipice, above · standard not met in 1 of 4 years3 indicators
  • VN Ľadovosite Dolná Telka (below Halič, above the Ľadovo Reservoir) · standard not met in 1 of 4 years · nitrates in the groundwater nearby 0.5 mg/l3 indicators
  • Krupinica č. 1site Šahy, above (road bridge Šahy – Hrkovce) · standard not met in 4 of 4 years · nitrates in the groundwater nearby 0.5 mg/l2 indicators
  • Štiavnica č. 1 (Šahy)site Štiavnica, mouth · standard not met in 4 of 4 years · nitrates in the groundwater nearby 0.5 mg/l2 indicators
  • Štrkovisko Šahysite Šahy, above (road bridge Šahy – Hrkovce) · standard not met in 4 of 4 years · nitrates in the groundwater nearby 13.9 mg/l2 indicators
  • Bebrava (Krupina)site Seliko Krupina, above · standard not met in 1 of 4 years2 indicators
  • Ipeľ č. 6site Breznička (below Banský potok) · standard not met in 1 of 4 years · nitrates in the groundwater nearby 0.5 mg/l2 indicators
  • Ipeľ č. 7site Breznička (below Banský potok) · standard not met in 1 of 4 years · nitrates in the groundwater nearby 5.1 mg/l2 indicators
  • Krupinica č. 2site Plášťovce, above · standard not met in 1 of 4 years · nitrates in the groundwater nearby 0.5 mg/l2 indicators
  • Litava č. 1site Cerovo, below · standard not met in 1 of 4 years · nitrates in the groundwater nearby 0.5 mg/l2 indicators
  • VN Krupinasite Seliko Krupina, above · standard not met in 1 of 4 years2 indicators
  • Krupinica č. 3site Vĺčok, near · standard not met in 1 of 4 years · nitrates in the groundwater nearby 4.1 mg/l1 indicator
  • VN Nenincesite Nenince · standard not met in 1 of 4 years · nitrates in the groundwater nearby 0.5 mg/l1 indicator
  • VN Ožďanysite VN Ožďany, above · standard not met in 1 of 4 years1 indicator
  • Krivánsky potoksite Lučenec, below · standard not met in 2 of 4 years · nitrates in the groundwater nearby 2.4 mg/lno unmet standard
  • Tuhársky potoksite Stará Halič, above · standard not met in 2 of 4 years · nitrates in the groundwater nearby 2.4 mg/lno unmet standard
  • Štiavnica č. 2 (Krupina)site Štiavnica, below the mouth of the Ilijský potok · standard not met in 1 of 4 years · nitrates in the groundwater nearby 0.5 mg/lno unmet standard
  • Ipeľ č. 2site Kubáňovo · standard not met in 0 of 4 years · nitrates in the groundwater nearby 9.7 mg/lno unmet standard
  • Ipeľ č. 3site Kubáňovo · standard not met in 0 of 4 years · nitrates in the groundwater nearby 13.9 mg/lno unmet standard
  • Ipeľ č. 4site Ipeľ, bridge Bystrička – Hrabovská · standard not met in 0 of 4 years · nitrates in the groundwater nearby 8.8 mg/lno unmet standard
  • Ipeľ č. 5site Ipeľ, bridge Bystrička – Hrabovská · standard not met in 0 of 4 yearsno unmet standard
  • Tisovníksite Vieska · standard not met in 0 of 4 yearsno unmet standard
  • VN Veľké Dravcesite VN Veľké Dravce, above · standard not met in 0 of 4 yearsno unmet standard
  • VN Ľuborečsite Ľuboreč, above · standard not met in 0 of 4 yearsno unmet standard
  • Ľuborečský potoksite Ľuboreč, above · standard not met in 0 of 4 years · nitrates in the groundwater nearby 0.5 mg/lno unmet standard

What most often fails

Number of sites in the river basin that failed this indicator in 2025

  1. benzo(a)pyrenePAHs (combustion and deposition)12
  2. AOX (adsorbable organic halogens)Harmful organic substances6
  3. total phosphorusNutrients and nitrogen3
  4. calciumSalts, pH and minerals2
  5. nitritesNutrients and nitrogen2
  6. conductivitySalts, pH and minerals2
  7. zincMetals2
  8. leadMetals1
  9. dissolved oxygenOxygen and organic matter1
  10. nitratesNutrients and nitrogen1
  11. pHSalts, pH and minerals1
  12. PFOS (perfluorooctane sulfonate)Harmful organic substances1
  • 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.