The Public Water Supplies (Scotland) Regulations 2014

[F1PART BSChemical and indicator parameters

1.(1) [F2For] a parameter in Table 1, the method of analysis used must, as a minimum, be capable of measuring concentrations equal to the prescribed concentration or value for the parameter with—

(a)a limit of quantification of 30 % or less of the prescribed concentration or value for the parameter; and

(b)an uncertainty of measurement as specified in Table 1 for the parameter.

(2) The result of the analysis for a parameter in Table B or Table C must be expressed using at least the same number of significant figures as the prescribed concentration or value for the parameter in the table.

2.  The uncertainty of measurement specified in Table 1 for a parameter must not be used as an additional tolerance to the prescribed concentration or value for the parameter.S

F33.  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S

[F4Minimum performance characteristic: uncertainty of measurement

ParameterUncertainty of measurement (% of prescribed concentration or value, except pH) (Note 1)Notes
Notes—
Note 1: Uncertainty of measurement is a non-negative parameter characterising the dispersion of the quantity values being attributed to a measurand, based on the information used. The performance criterion for measurement uncertainty (k = 2) is the percentage of the parametric value stated in the table or any stricter value. The uncertainty of measurement must be estimated at the level of the parametric value, unless otherwise specified.
Note 2: If the value of uncertainty of measurement cannot be met, the best available technique must be selected (up to 60%).
Note 3: The method determines total cyanide in all forms.
Note 4: The value for the uncertainty of measurement is expressed in pH units.
Note 5: Reference method European standard EN ISO 8467:1995 entitled “Water quality - Determination of permanganate index (ISO 8467:1993)”.
Note 6: The performance characteristics for individual pesticides are given as an indication. Values for the uncertainty of measurement as low as 30 % can be achieved for several pesticides, higher values up to 80% may be allowed for a number of pesticides.
Note 7: The performance characteristics apply to individual substances, specified at 25% of the prescribed concentration or value for the corresponding parameter in Table B.
Note 8: The performance characteristics apply to individual substances, specified at 50% of the prescribed concentration or value for the corresponding parameter in Table B.
Note 9: The uncertainty of measurement must be estimated at the level of 3 mg/l of the total organic carbon in accordance with European standard EN 1484:1997 entitled “Water analysis - Guidelines for the determination of total organic carbon and dissolved organic carbon”.
Note 10: The uncertainty of measurement must be estimated at the level of 1.0 nephelometric turbidity units in accordance with European standard EN ISO 7027-1:2016 entitled “Water quality - Determination of turbidity - Part 1: Quantitative methods (ISO 7027-1:2016)” or another equivalent standard method.]]
Aluminium25
Ammonium40
Acrylamide30
Antimony40
Arsenic30
Benzo(a)pyrene50Note 2
Benzene40
Bisphenol A50
Boron25
Bromate40
Cadmium25
Chloride15
Chlorate40
Chlorite40
Chromium30
Conductivity20
Copper25
Cyanide30Note 3
1,2-dichloroethane40
Epichlorohydrin30
Fluoride20
HAAs50
Hydrogen ion concentration (in pH)0.20Note 4
Iron30
Lead30
Manganese30
Mercury30
Microcystin-LR30
Nickel25
Nitrate15
Nitrite20
Oxidisability50Note 5
Pesticides30Note 6
PFAS50
Polycyclic aromatic hydrocarbons40Note 7
Selenium40
Sodium15
Sulphate15
Tetrachloroethene40Note 8
Trichloroethene40Note 8
Trihalomethanes – total40Note 7
Total organic carbon30Note 9
Turbidity30Note 10
Uranium30
Vinyl chloride50