SCHEDULE 10Sampling and analysis for parameters other than radioactive substances in water bottled and labelled as “spring water” and bottled drinking water

Regulation 25(1)(a)

PART 1General

Analysis of samples1

1

The district council must ensure that each sample is analysed in accordance with Annex III to Directive 98/83 and this Schedule.

2

For each parameter specified in the first column of Table 1 in Part 2 the method of analysis is specified in the second column of that table.

3

For each parameter specified in the first column of Table 2 in Part 2 the method of analysis is one that is capable of—

a

measuring concentrations and values with the trueness and precision specified in the second and third columns of that table; and

b

detecting the parameter at the limit of detection specified in the fourth column of that table.

4

For hydrogen ion, the method of analysis must be capable of measuring a value with a trueness of 0.2pH unit and a precision of 0.2 pH unit.

5

The method of analysis used for odour and taste parameters must be capable of measuring values equal to the parametric value with a precision of 1 dilution number at 25 ºC.

6

For the purpose of this paragraph—

  • “limit of detection” is—

    1. a

      three times the relative within-batch standard deviation of a natural sample containing a low concentration of the parameter; or

    2. b

      five times the relative within-batch standard deviation of a blank sample;

  • “precision” (the random error) is twice the standard deviation (within a batch and between batches) of the spread of results about the mean;

  • “trueness” (the systematic error) is the difference between the mean value of the large number of repeated measurements and the true value.

Authorisation of alternative methods of analysis2

1

The Agency may authorise a method different from that set out in Part 2 if satisfied that it is at least as reliable.

2

An authorisation may be time-limited and may be revoked at any time.

Sampling and analysis by persons other than district councils3

1

A district council may enter into an arrangement for any person to take and analyse samples on its behalf.

2

A district council must not enter into an arrangement under paragraph (1) unless—

a

it is satisfied that the task will be carried out promptly by a person competent to perform it; and

b

it has made arrangements that ensure that any breach of these Regulations is communicated to it immediately, and any other result is communicated to it within 28 days.

PART 2Methods of analysis and performance characteristics

Table 1Prescribed methods of analysis

Parameter

Method

Clostridium perfringens (including spores)

Membrane filtration followed by anaerobic incubation of the membrane on m-CP agar1 at 44 ±1ºC for 21± 3 hours. Count opaque yellow colonies that turn pink or red after exposure to ammonium hydroxide vapours for 20 to 30 seconds.

Coliform bacteria

BS-EN ISO 9308-1

Colony count 22ºC – enumeration of culturable microorganisms

BS-EN ISO 6222

Colony count 37ºC – enumeration of culturable microorganisms

BS-EN ISO 6222

Enterococci

BS-EN ISO 7899-2

Escherichia coli (E. Coli)

BS-EN ISO 9308-1

Pseudomonas aeruginosa

BS-EN ISO 12780

1 Use the following method to make m-CP agar:

Make a basal medium consisting of—

Tryptose

30.0g

Yeast extract

20.0g

Sucrose

5.0g

L-cysteine hydrochloride

1.0g

MgSO4.7H2O

0.1g

Bromocresol purple

40.0mg

Agar

15.0g

Water

1,000.0ml

Dissolve the ingredients of basal medium, adjust pH to 7.6 and autoclave at 121ºC for 15 minutes. Allow the medium to cool.

Dissolve—

D-cycloserine

400.0mg

Polymyxine-B sulphate

25.0mg

Indoxl-β-D-glucoside

60.0mg

into 8ml sterile water and add it to the medium.

Add to the medium—

Filter-sterilised 0.5% phenolphthalein diphosphate solution

20.0ml

Filter-sterilised 4.5% FeCl3.6H2O

2.0ml

Table 2Prescribed performance characteristics for methods of analysis

Parameters

Trueness % of prescribed concentration or value specification

Precision % of prescribed concentration or value or specification

Limit of detection % of prescribed concentration or value or specification

Aluminium

10

10

10

Ammonium

10

10

10

Antimony

25

25

25

Arsenic

10

10

10

Benzene

25

25

25

Benzo(a)pyrene

25

25

25

Boron

10

10

10

Bromate

25

25

25

Cadmium

10

10

10

Chloride

10

10

10

Chromium

10

10

10

Conductivity

10

10

10

Copper

10

10

10

Cyanide1

10

10

10

1,2-dichloroethane

25

25

10

Fluoride

10

10

10

Iron

10

10

10

Lead

10

10

10

Manganese

10

10

10

Mercury

20

10

20

Nickel

10

10

10

Nitrate

10

10

10

Nititre

10

10

10

Oxidisability2

25

25

10

Pesticides and related products3

25

25

25

Polycyclic aromatic hydrocarbons4

25

25

25

Selenium

10

10

10

Sodium

10

10

10

Sulphate

10

10

10

Tetrachloroethene5

25

25

10

Tetrachloromethane

20

20

20

Trichloroethene5

25

25

10

Trihalomethanes4

25

25

10

1 The method of analysis should determine total cyanide in all forms.

2 Oxidation should be carried out for 10 minutes at 100ºC under acid conditions using permanganate.

3 The performance characteristics apply to each individual pesticide and will depend on the pesticide concerned.

4 The performance characteristics apply to the individual substances specified at 25% of the parametric value in Table B in Part 2, Schedule 7.

5 The performance characteristics apply to the individual substance specified at 50% of the parametric value in Table B in Part 2, Schedule 7.