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Schedule 3 QUALITY AND ADDITIONAL SAMPLING REQUIREMENTS

Changes not yet applied. Later legislation changes this provision in ways not yet written into the text below:

ParameterParametric valueMinimum sampling frequencyMethods of analysis and inspection

Notes

  1. 1.

    Samples may be taken at intervals of four weeks where samples taken in previous years show that the waters are of an appreciably higher standard than that required for the classification in question and the quality of the waters has not subsequently deteriorated and is unlikely to do so.

  2. 2.

    Samples must be taken in relation to this parameter when there are grounds for suspecting that there has been a deterioration in the quality of the waters or the substance is likely to be present in the waters.
Micro-biological:
Total coliforms10,000/100mlFortnightly (see Note 1)Fermentation in multiple tubes. Sub-culturing of the positive tubes on a confirmation medium. Either counting according to MPN (most probable number) or membrane filtration, culturing on an appropriate medium, sub-culturing and identification of the suspect colonies.
Faecal coliforms2,000/100mlFortnightly (see Note 1)The incubation temperature is variable according to whether total or faecal coliforms are being investigated.
SalmonellaAbsent in 1 litre(see Note 2)Membrane filtration, culturing on an appropriate medium, sub-culturing and identification of the suspect colonies.
Entero virusesNo plaque forming units in 10 litres(see Note 2)Concentration (by filtration, flocculation or centrifuging) and confirmation.
Physico-chemical:
PH6 to 9(see Note 2)Electrometry with calibration at pH 7 and 9.
ColourNo abnormal change in colourFortnightly (see Note 1)Visual inspection or photometry with standards on the platinum cobalt scale.
Mineral oilsNo film visible on the surface of the water and no odourFortnightly (see Note 1)Visual and olfactory inspection.
Surface-active substances reacting with methylene blueNo lasting foamFortnightly (see Note 1)Visual inspection.
Phenols (phenol indices)No specific odourFortnightly (see Note 1)Olfactory inspection.
≤0.05 mg/litre (C6H5OH)(see Note 2)Absorption spectrophotometry 4-aminoantipyrine (4 AAP)
Transparency1 metreFortnightly (see Note 1)Secchi’s disc.