{
  "url": "https://openlegislation.uk/surface-waters-shellfish-classification-regulations-northern-ireland-1997/schedule-1",
  "json_url": "https://openlegislation.uk/surface-waters-shellfish-classification-regulations-northern-ireland-1997/schedule-1.json",
  "legislation": "nisr/1997/489",
  "legislation_title": "The Surface Waters (Shellfish) (Classification) Regulations (Northern Ireland) 1997",
  "legislation_url": "https://openlegislation.uk/surface-waters-shellfish-classification-regulations-northern-ireland-1997",
  "path": "schedule/1",
  "kind": "schedule",
  "number": "1",
  "heading": "Criteria for classification of waters as shellfish waters",
  "text": "No in Annex 1 to 79/923/EEC\nParameter\nUnits\nRequirements to be satisfied\nReference methods of analysis\nMinimum sampling and measuring frequency\n1.\npH\npH unit\n≥7 and ≤9\n— electrometry\nMeasured in situ at the time of sampling\nQuarterly\n3.\nColoration (after filtration)\nmg Pt/1\nA discharge affecting shell- fish waters must not cause the colour of the waters after filtration to deviate by more than 10 mg Pt/1 from the colour of waters not so affected.\n— Filter through a 0.45 um membrane\nPhotometric method, using the platinum/cobalt scale\nQuarterly\n4.\nSuspended solids\nmg/1\nA discharge affecting shell- fish waters must not cause the suspended solids content of the water to exceed by more than 30% the content of waters not so affected\nFiltration through a 0.45 μm membrane, drying at 105°C and weighing\n— Centrifuging (for at least 5 minutes, with mean acceleration 2,800 to 3,200g), drying at 105°C and weighing\nQuarterly\n5.\nSalinity\n‰\n≤40‰\n— A discharge affecting shellfish waters must not cause their salinity to exceed by more than 10% the salinity of waters not so affected\nConductivity\nMonthly\n6.\nDissolved oxygen\nsaturation %\n≥70% (average value) Should an individual measurement indicate a value lower than 70%, measurements shall be repeated\nAn individual measurement may not indicate a value of less than 60% unless there are no harmful consequences for the development of shellfish colonies\n— Winkler’s method\n— Electrochemical method\nMonthly, with a minimum of 1 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\n7.\nPetroleum hydrocarbons\nHydrocarbons must not be present in the shellfish water in such quantities as to:\nproduce a visible film on the surface of the water and/ or a deposit on the shellfish\nhave harmful effects on shellfish\nVisual examination\nQuarterly\n8.\nOrganohalo- genated substances\nThe concentration of each substance in the shellfish waters or in shellfish flesh must not reach or exceed a level which has harmful effects on the shellfish and their larvae\nGas chromatography after extraction with suitable solvents and purification\nHalf-yearly\n9.\nMetals\nSilver Ag\nArsenic As\nCadmium Cd\nChromium Cr\nCopper Cu\nMercury Hg\nNickel Ni\nLead Pb\nZinc Zn\nmg/1\nThe concentration of each substance in the shellfish waters or in the shellfish flesh must not exceed a level which gives rise to harmful effects on the shellfish and their larvae\nThe synergic effects of these metals must be taken into consideration\nSpectrometry of atomic absorption preceded, where appropriate, by concentration and/or extraction\nHalf-yearly\n11.\nSubstances affecting the taste of shellfish\nConcentration should be lower than that which is liable to impair the taste of the shellfish\nExamination of the shellfish by tasting where the presence of one of these substances is presumed",
  "extent": "N.I.",
  "status": "prospective",
  "version": "current",
  "annotations": [
    {
      "type": "I",
      "label": "I1",
      "text": "Sch. 1 in operation at 5.1.1998, see reg. 1"
    }
  ],
  "outstanding_effects": [
    {
      "type": "coming into force",
      "affecting": "nisr/1997/489",
      "affecting_title": "The Surface Waters (Shellfish) (Classification) Regulations (Northern Ireland) 1997"
    },
    {
      "type": "words substituted",
      "affecting": "nisr/2009/61",
      "affecting_title": "The Surface Waters (Shellfish) (Classification) (Amendment) Regulations (Northern Ireland) 2009"
    }
  ],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/nisr/1997/489/schedule/1",
    "retrieved_at": "2026-10-29T02:26:19.805844+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."
}