{
  "url": "https://openlegislation.uk/surface-waters-fishlife-classification-regulations-northern-ireland-1997/schedule-2/part-I",
  "json_url": "https://openlegislation.uk/surface-waters-fishlife-classification-regulations-northern-ireland-1997/schedule-2/part-I.json",
  "legislation": "nisr/1997/488",
  "legislation_title": "The Surface Waters (Fishlife) (Classification) Regulations (Northern Ireland) 1997",
  "legislation_url": "https://openlegislation.uk/surface-waters-fishlife-classification-regulations-northern-ireland-1997",
  "path": "schedule/2/part/I",
  "kind": "part",
  "number": "I",
  "heading": "Guideline values in relation to the quality of salmonid and cyprinid waters",
  "text": "No in Annex 1 to 78/659/EEC\nParameter\nSalmonid waters (guideline values and comments)\nCyprinid waters (guideline values and comments)\nMethods of analysis or inspection\nMinimum sampling and measuring frequency\nObservations\n2.\nDissolved oxygen (mg/1O2)\n50%≥9\n100%≥7\n50%≥8\n100%≥5\nWinkler’s method or specific electrodes (electro- chemical method)\nMonthly, minimum sample represent- ative of low oxygen conditions on the day of sampling. However, where major daily variations are suspected, a minimum of 2 samples in 1 day shall be taken\n4.\nSuspended solids (mg/1)\n≤25(O)\nFiltration through a 0.45μm filtering membrane, or centrifugation (5 minutes minimum, average acceleration of 2,800 to 3,200g) drying at 105°C and weighing\nThe values shown are average concentrations and do not apply to suspended solids with harmful chemical properties Floods are liable to cause particularly high concentrations\n5.\nBOD5 (mg/1O2)\n≤3\n≤6\nDetermination of O2 by the Winkler method before and after 5 days incubation in complete darkness at 20°C ±1°C (nitrification should not be inhibited)\n7.\nNitrites (mg/1 NO2)\n≤0.01\n≤0.03\nMolecular absorption spectro- photometry\n10.\nNon-ionized ammonia (mg/1 NH3)\n≤0.005\n≤0.005\nMolecular absorption spectro- photometry using indophenol blue or Nessler’s method associated with pH and temperature determ-ination\nMonthly\nValues for non-ionized ammonia may be exceed in the form of minor peaks in the daytime.\n11.\nTotal ammonium (mg/1 NH4)\nIn order to diminish the risk of toxicity due to non-ionised ammonia, of oxygen consumption due to nitrification and of eutrophication, the concentrations of total ammonium should not exceed 0.04 mg/1 for salmonid waters and 0.2 mg/1 for cyprinid waters\n14.\nDissolved copper (mg/1 Cu)\n≤0.04\n≤0.04\nAtomic absorption spectrometry\nThe values correspond to a water hardness of 100 mg/1 CaCO3 For hardness levels between 10 and 300 mg/1 corresponding limit values can be found in Part II of this Schedule",
  "extent": "N.I.",
  "status": "prospective",
  "version": "current",
  "annotations": [
    {
      "type": "I",
      "label": "I1",
      "text": "Sch. 2 Pt. I in operation at 5.1.1998, see reg. 1"
    }
  ],
  "outstanding_effects": [
    {
      "type": "coming into force",
      "affecting": "nisr/1997/488",
      "affecting_title": "The Surface Waters (Fishlife) (Classification) Regulations (Northern Ireland) 1997"
    },
    {
      "type": "coming into force",
      "affecting": "nisr/1997/488",
      "affecting_title": "The Surface Waters (Fishlife) (Classification) Regulations (Northern Ireland) 1997"
    },
    {
      "type": "words substituted",
      "affecting": "nisr/2007/405",
      "affecting_title": "The Surface Waters (Fishlife) (Classification) (Amendment) Regulations (Northern Ireland) 2007 (revoked)"
    }
  ],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/nisr/1997/488/schedule/2/part/I",
    "retrieved_at": "2026-10-29T02:26:20.518764+00:00"
  },
  "licence": "Open Government Licence v3.0",
  "licence_url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
  "attribution": "Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives."
}