{
  "url": "https://openlegislation.uk/surface-waters-abstraction-for-drinking-water-classification-regulations-1996/schedule-2/part-I",
  "json_url": "https://openlegislation.uk/surface-waters-abstraction-for-drinking-water-classification-regulations-1996/schedule-2/part-I.json",
  "legislation": "uksi/1996/3001",
  "legislation_title": "The Surface Waters (Abstraction for Drinking Water) (Classification) Regulations 1996",
  "legislation_url": "https://openlegislation.uk/surface-waters-abstraction-for-drinking-water-classification-regulations-1996",
  "path": "schedule/2/part/I",
  "kind": "part",
  "number": "I",
  "heading": "METHOD OF MEASURING THE VALUES OF PARAMETERS",
  "text": "No. in Annex II to 75/440/EEC\nParameters\nUnits\nLimit of detection\nPrecision\nAccuracy\nMethod of measurement\nMaterials recommended for the container\n1 “Limit of detection” means the minimum value of the parameter examined which it is possible to detect.\n2 “Precision” means the range within which 95% of the results of measurements made on a single sample, using the same method, are located.\n3 “Accuracy” means the difference between the true value of the parameter examined and the average experimental value obtained.\n4 If the samples contain so much suspended matter as to require special preliminary treatment, the accuracy values shown in the above Table may as an exception be exceeded and are to be regarded as a target. These samples must be treated so as to ensure that the analysis covers the largest quantity of substances to be measured.\n5 For waters classified as DW1 or DW2.\n6 For waters classified as DW3.\n7 For waters classified as DW1.\n8 For waters classified as DW2 or DW3.\n9 Mixture of six standard substances all of the same concentration to be taken into consideration: fluoranthene; 3,4-benzofluoranthene; 11, 12-benzofluoranthene; 3,4-benzopyrene; 1,12-benzoperylene; indeno (1,2,3-cd) pyrene.\n10 Mixture of three substances all of the same concentration to be taken into consideration: parathion, hexachlorocyclohexane, dieldrin.\n2\nColoration (after simple filtration)\nmg/l Pt Scale\n5\n10%\n20%\nFiltering through a glass fibre membrane.\nPhotometric method using platinum-cobalt scale.\n4\nTemperature\n°C\n—\n0.5\n1\nThermometry.\nMeasured in situ at the time of sampling without prior treatment of the sample.\n7\nNitrates\nmg/l NO3\n2\n10%\n20%\nMolecular absorption spectrophotometry.\n8\nFluorides\nmg/l F\n0.05\n10%\n20%\nMolecular absorption spectrophotometry after distillation if necessary.\nIon selective electrodes.\n10\nDissolved iron\nmg/l Fe\n0.02\n10%\n20%\nAtomic absorption spectrophotometry after filtering through 0.45 μm filter membrane.\nMolecular absorption spectrophotometry after filtering through 0.45 μm filter membrane.\n12\nCopper\nmg/l Cu\n0.005\n10%\n20%\nAtomic absorption spectrophotometry.\nPolarography.\n13\nZinc\nmg/l Zn\n0.02\n10%\n20%\nAtomic absorption spectrophotometry.\nMolecular absorption spectrophotometry.\n19\nArsenic\nmg/l As\n0.01\n10%\n20%\nAtomic absorption spectrophotometry.\nMolecular absorption spectrophotometry.\n20\nCadmium\nmg/l Cd\n0.001\n30%\n30%\nAtomic absorption spectrophotometry.\nPolarography.\n21\nTotal chromium\nmg/l Cr\n0.01\n20%\n30%\nAtomic absorption spectrophotometry.\nMolecular absorption spectrophotometry.\n22\nLead\nmg/l Pb\n0.01\n20%\n30%\nAtomic absorption spectrophotometry.\nPolarography.\n23\nSelenium\nmg/l Se\n0.005\n10%\n10%\nAtomic absorption spectrophotometry.\n24\nMercury\nmg/l Hg\n0.0002\n30%\n30%\nFlameless atomic absorption spectrophotometry (cold vaporisation).\n25\nBarium\nmg/l Ba\n0.02\n15%\n30%\nAtomic absorption spectrophotometry.\n26\nCyanide\nmg/l CN\n0.01\n20%\n30%\nMolecular absorption spectrophotometry.\n27\nSulphates\nmg/l SO4\n10\n10%\n10%\nGravimetric analysis.\nEDTA compleximetry.\nMolecular absorption spectrophotometry.\n31\nPhenols (phenol index) paranitraniline 4-aminoantipyrene\nmg/l C6H5OH\n0.0005 0.001\n0.0005 30%\n0.0005 50%\nMolecular absorption spectrophotometry 4-aminoantipyrene method.\nParanitraniline method.\nGlass.\n32\nDissolved or emulsified hydrocarbons\nmg/l\n0.01 0.04\n20% 20%\n30% 30%\nInfra-red spectrometry after extraction by carbon tetrachloride.\nGravimetry after extraction by petroleum ether.\nGlass\n33\nPolycyclic aromatic hydrocarbons\nmg/l\n0.00004\n50%\n50%\nMeasurement of fluorescence in the UV after thin layer chromatography.\nComparative measurements in relation to a mixture of six control substances with the same concentration.\nGlass or aluminium.\n34\nTotal pesticides (parathion, hexachloro-cyclohexane, dieldrin)\nmg/l\n0.0001\n50%\n50%\nGas or liquid chromatography after extraction by suitable solvents and purification.\nIdentification of the constituents of the mixture.\nQuantitative analysis.\nGlass.\n39\nAmmonium\nmg/l NH4\n0.1\n10%\n20%\nMolecular absorption spectrophotometry.",
  "extent": null,
  "status": null,
  "version": "current",
  "annotations": [
    {
      "type": "footnote",
      "label": "f1",
      "text": "1 “Limit of detection” means the minimum value of the parameter examined which it is possible to detect."
    },
    {
      "type": "footnote",
      "label": "f2",
      "text": "2 “Precision” means the range within which 95% of the results of measurements made on a single sample, using the same method, are located."
    },
    {
      "type": "footnote",
      "label": "f3",
      "text": "3 “Accuracy” means the difference between the true value of the parameter examined and the average experimental value obtained."
    },
    {
      "type": "footnote",
      "label": "f4",
      "text": "7 For waters classified as DW1."
    },
    {
      "type": "footnote",
      "label": "f5",
      "text": "5 For waters classified as DW1 or DW2."
    },
    {
      "type": "footnote",
      "label": "f6",
      "text": "4 If the samples contain so much suspended matter as to require special preliminary treatment, the accuracy values shown in the above Table may as an exception be exceeded and are to be regarded as a target. These samples must be treated so as to ensure that the analysis covers the largest quantity of substances to be measured."
    },
    {
      "type": "footnote",
      "label": "f7",
      "text": "8 For waters classified as DW2 or DW3."
    },
    {
      "type": "footnote",
      "label": "f8",
      "text": "10 Mixture of three substances all of the same concentration to be taken into consideration: parathion, hexachlorocyclohexane, dieldrin."
    }
  ],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/uksi/1996/3001/schedule/2/part/I",
    "retrieved_at": "2026-10-29T12:31:11.165973+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."
}