# The Surface Waters (Abstraction for Drinking Water) (Classification) (Scotland) Regulations 1996, Part 1: METHOD OF MEASURING THE VALUES OF PARAMETERS


No. in Annex I to the 1975 Directive
Parameters
Limit of detection
Precision
Accuracy
Method of measurement
Materials recommended for the container
General note: Samples taken at the abstraction point are analysed and measured after sieving (wire mesh sieve) to remove any floating debris such as wood or plastic.
1For waters classified as DW1, Schedule 2 limit.
2For waters classified as DW2 and DW3.
3For waters classified as DW3.
4For waters classified as DW1, DW2 and DW3, Schedule 1 limit.
5For waters classified as DW2, Schedule 1 limit, and DW3.
6For waters classified as DW2 and DW3, Schedule 2 limit.
7Mixture of six standard substances all of the same concentration to be taken into consideration: fluoranthene; 3, 4-benzofluoranthene; 11, 12-benzofluranthene; 3, 4-benzopyrene; 1, 12-benzoperylene; indano/1, 2, 3-ed/pyrene.
8Mixture of three substances all of the same concentration to be taken into consideration: parathion, hexachlorocyclohexane, dieldrin.
9If the samples contain so much suspended matter as to require special preliminary treatment, the accuracy values shown in this Part of Schedule 3 may as an exception be exceeded and will 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.
10As this method is not in current use in all Member States it is not certain that the limit of detection required for checking values in the 1975 Directive can be attained.
11Absence in 5,000 m1 (for waters classified DW1, Schedule 2 limit) and absence in 1,000 m1 (for waters classified DW2, Schedule 2 limit).
12“Limit of detection” means the minimum value of the parameter examined which it is possible to detect.
13“Precision” means the range within which 95% of the results of measurements made on a single sample, using the same method, are located.
14“Accuracy” means the difference between the true value of the parameter examined and the average experimental value obtained.
1
pH
pH unit
–
0.1
0.2
– Electrometry. Measured in situ at the time of sampling without prior treatment of the sample.
2
Coloration (after simple filtration)
mg/1 Pt Scale
5
10%
20%
– Filtering through a glass fibre membrane. Photometric method using platinum-cobalt scale.
3
Total suspended solids
mg/1 SS
–
5%
10%
– Filtering through a 0.45μm filter membrane, drying at 105°C and weighing
– Centrifuging (for at least 5 mins with mean acceleration of 2,800 to 3,200g) drying at 105°C and weighing.
4
Temperature
°C
–
0.5
1
– Thermometry. Measured in situ at the time of sampling without prior treatment of the sample.
5
Conductivity at 20°C
μs/cm
–
5%
10%
– Electrometry.
No. in Annex I to the 1975 Directive
Parameters
Limit of
Precision detection
Accuracy
Method of measurement recommended for the container
Materials
6
Odour
dilution factor at 25 °C
–
–
–
– By successive dilutions.
Glass.
7
Nitrates
mg/1 NO3
2
10%
20%
– Molecular absorption spectrophotometry.
8
Fluorides
mg/1 F
0.05
10%
20%
Molecular absorption spectrophotometry after distillation if necessary.
Ion selective electrodes.
10
Dissolved iron
mg/1 Fe
0.02
10%
20%
Atomic absorption spectrophotometry after filtering through a filter membrane (0.45μm).
Molecular absorption spectrophotometry after filtering through a 0.45μm filter membrane.
11
Manganese
mg/1 Mn
0.01
0.02
10%
10%
20%
20%
Atomic absorption spectrophotometry
Atomic absorption spectrophotometry
Molecular absorption spectrophotometry.
12
Copper
mg/1 Cu
0.005
0.02
10%
10%
20%
20%
Atomic absorption spectrophotometry
Polarography
Atomic absorption spectrophotometry
Molecular absorption spectrophotometry
Polarography.
No. in Annex I to the 1975 Directive
Parameters
Limit of detection
Precision
Accuracy
Method of measurement
Materials recommended for the container
13
Zinc
mg/1 Zn
0.01
0.02
10%
10%
20%
20%
Atomic absorption spectrophotometry
Atomic absorption spectrophotometry
Molecular absorption spectrophotometry.
14
Boron
mg/1 B
0.1
10%
20%
Molecular absorption spectrophotometry
Atomic absorption spectrophotometry
Materials not containing boron in any significant quantities.
19
Arsenic
mg/1 As
0.002
0.01
20%
20%
Atomic absorption spectrophotometry
Atomic absorption spectrophotometry
Molecular absorption spectrophotometry.
20
Cadmium
mg/1 Cd
0.0002
0.0015
30%
30%
Atomic absorption spectrophotometry
Polarography.
21
Total Chromium
mg/1 Cr
0.01
20%
30%
Atomic Absorption spectrophotometry
Molecular absorption spectrophotometry.
22
Lead
mg/1 Pb
0.01
20%
30%
Atomic absorption spectrophotometry
Polarography.
23
Selenium
mg/1 Se
0.005
– Atomic absorption spectrophotometry.
24
Mercury
mg/1 Hg
0.0001
0.0002
30%
30%
– Flameless atomic absorption spectrophotometry (cold vaporisation).
25
Barium
mg/1 Ba
0.02
15%
30%
– Atomic absorption spectrophotometry.
26
Cyanide
mg/1 CN
0.01
20%
30%
– Molecular absorption spectrophotometry.
27
Sulphates
mg/1 SO4
10
10%
10%
Gravimetric analysis.
EDTA compleximetry.
Molecular absorption spectrophotometry.
28
Chlorides
mg/1 C1
10
10%
10%
Titration (Mohr’s method).
Molecular absorption spectrophotometry.
29
Surfactants (reacting with methylene blue)
mg/1 (laury1 sulphate)
0.05
20%
– Molecular absorption spectrophotometry.
30
Phosphates
mg/1 P2O5
0.02
10%
20%
– Molecular absorption spectrophotometry.
31
Phenols (phenol Index)
mg/1 C6H5OH
0.0005
0.0015
0.0005
30%
0.0005
50%
Molecular absorption spectrophotometry 4-aminoantipyrine method.
Paranitraniline method.
Glass.
32
Dissolved or emulsified hydrocarbons
mg/1
0.01
0.04
20%
30%
Infra-red spectrometry after extraction by carbon tetrachloride
Gravimetry after extraction by petroleum ether.
Glass.
33
Polycyclic aromatic hydrocarbons
mg/1
0.00004
50%
50%
– Measurement of fluorescence in the UV after thin layer chromatography.
Comparative measurement in relation to a mixture of six control substances with the same concentration.
Glass or aluminium.
34
Total pesticides (parathion, hexachlorocyclohexane, dieldrin)
mg/1
0.0001
50%
50%
– Gas or liquid chromatography after extraction by suitable solvents and purification. Identification of the constituents of the mixture. Quantitative analysis.
Glass.
35
Chemical oxygen demand (COD)
mg/1 02
15
20%
20%
– Potassium dichromate method.
36
Dissolved oxygen saturation rate
%
5
10%
10%
Winkler’s method
Electrochemical method.
Glass.
37
Biochemical oxygen demand (BOD5) at 20°C without nitrification
mg/1 02
2
1.5
2
– Determination of dissolved oxygen before and after five day incubation at 20 °C ± 1°C in complete darkness. Addition of a nitrification inhibitor.
38
Nitrogen by Kjeldahl method (except in NO2 and NO3)
mg/1 N
0.3
0.5
0.5
– Mineralisation, distillation by Kjeldahl method and ammonium determination by means of molecular absorption spectrophotometry or titration.
39
Ammonium
mg/1 NH4
0.01
0.1
0.03
10%
0.03
20%
– Molecular absorption spectrophotometry.
40
Substances extractable with chloroform
mg/l
– Extraction at neutral pH value by purified chloroform, evaporation in vacuo at room temperature, weighing of residue.
43
Total coliforms
/100ml
5
500
Culture at 37 °C on an appropriate specific solid medium (such as Tergitol lactose agar, Endo agar, 0.4% Teepol broth) with filtration or without filtration and colony count. Samples must be diluted or, where appropriate, concentrated in such a way as to contain between 10 and 100 colonies. If necessary, identification by gasification.
Method of dilution with fermentation in liquid substrates in at least three tubes in three dilutions. Sub-culturing of the positive tubes on a confirmation medium. Count according to MPN (most probable number). Incubation temperature: 37°C ± 1 °C.
Sterilised glass.
44
Faecal coliforms
/100ml
2
200
Culture at 44 °C on an appropriate specific solid medium (such as Tergitol lactose agar, Endo agar, 0.4% Teepol broth) with filtration or without filtration and colony count. Samples must be diluted or, where appropriate, concentrated in such a way as to contain between 10 and 100 colonies. If necessary, identification by gasification.
Method of dilution with fermentation in liquid substrates in at least three tubes in three dilutions. Sub-culturing of the positive tubes on a confirmation medium. Count according to MPN (most probable number). Incubation temperature 44 °C ± 0.5 °C.
Sterilised glass.
45
Faecal streptococci
/100 ml
2
200
Culture at 37 °C on an appropriate solid medium (such as sodium azide) with filtration or without filtration and colony count. Samples must be diluted or, where appropriate concentrated in such a way as to contain between 10 and 100 colonies.
Method of dilution in sodium azide broth in at least three tubes in three dilutions. Count according to MPN (most probable number).
Sterilised glass.
46
Salmonella
1/5,000ml
1/1,000ml
Concentration by filtration (on membrane or appropriate filter).
Inoculation into pre-enrichment medium. Enrichment and transfer into isolating gelese – Identification.
Sterilised glass.

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Source: https://www.legislation.gov.uk/uksi/1996/3047/schedule/3/part/1 (the official version)
Page: https://openlegislation.uk/surface-waters-abstraction-for-drinking-water-classification-scotland-regulations-1996/schedule-3/part-1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.