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DOCUMENT CONTROL

The only controlled version of this document can be accessed on the DWI Website – www.dwi.gov.uk/drinking-water-products/index.htm. Printed copies of this document, together with electronic copies held on local computers and other storage devices are uncontrolled. VVeerrssiioonn 55 –– OOccttoobbeerr 22001166

APPROVAL OF PRODUCTS FOR USE WITH DRINKING WATER

http://www.dwi.gov.uk/drinking-water-products/index.htm

UUNNCCOONNTTRROOLLLLEEDD IIFF PPRRIINNTTEEDD

Protocol 2 – General non-metallic products Page 2 of 25 Version 5 October 2016

INTRODUCTION This test protocol is one of a series prepared by the Drinking Water Inspectorate (DWI) on Products and Processes for use in Public Water Supply, to provide guidance to test laboratories on procedures to be used in evaluating the suitability of products for use in the treatment and distribution of water intended for human consumption. These procedures are designed to ensure a consistent approach to testing by the designated test laboratories. The protocols currently available are listed below.

NNuummbbeerr TTiittllee 0 Designated test laboratory requirements 1 Leaching of substances from products used in contact with water intended for

human consumption : Reporting requirements 2 Leaching of substances from products used in contact with water intended for

human consumption: General Methods 3 Leaching of substances from products used in contact with water intended for

human consumption : Admixtures for cementitious products 4 Leaching of substances from metallic products used in contact with water intended

for human consumption: General method – provisional 5 Leaching of substances from products used in contact with water intended for

human consumption : Water treatment membranes 6 Leaching of substances from non-metallic products used in contact with water

intended for human consumption : Filter media and ion exchange resins IMPACT OF EUROPEAN TECHNICAL REQUIREMENTS Currently a whole series of test methods are being prepared within CEN in support of the approval of products used with water intended for human consumption. As these are published any conflicting national test protocols will have to be withdrawn. It is currently anticipated that published EN standards will become available for most of the areas covered by these protocol during the next few years. AVAILABILITY Copies of these test protocols, together with information requirements for applicants, can be freely downloaded from our website – http://www.dwi.gov.uk/drinking-water-products/advice-and-approval/index.htm CONTACT For further information or help please contact us – Regulation 31 Enquiries, Tel +44 (0)300 068 6400 E-mail : [email protected] Revision notes – Version 2.0 – complete redraft to include BS EN 12873-1; 2.1 – correction of references in clause 6 to clauses in BS 6920-4, and clarification of clause 3.5.2 Version 3.0 – addition of Annex B; new table for factory made product leachates (new table 1) Version 4.0 – revision following publication of BS EN 12873-2; 4.1 – revision to cover pre-test commissioning and rinsing of test samples (clauses 2.2, 3.2, 4.4.1) and guidance on completion of the AQC checklist (Annex A); v4.2 – revisions to reflect new approval processes and requirements; v4.3 – reporting requirement for test water for leachate preparation (new section 7.2); v4.4 – clarification on test water in Section 2.3; v4.5 – changes in 2.1, correction in 3.3, additional requirement in 7.3 & 7.4; v4.6 – updating to cover all relevant regulations v4.7 Address change v4.8 Updated to include BS EN 15768 and Common Approach. v4.9 change to England and Wales Regulations. V5 - minor corrections.

http://www.dwi.gov.uk/drinking-water-products/advice-and-approval/index.htm

http://www.dwi.gov.uk/drinking-water-products/advice-and-approval/index.htm

mailto:[email protected]



CONTENTS

0 Introduction 5

1 Scope 5

2 Factory Made Products

2.1 Principle 7

2.2 Test sample pre-treatment 7

2.3 Leachate preparation 7

3. Site Applied products

3.1 Principle 8

3.2 Test sample pre-treatment 9


4 Cementitious products

4.1 Principle 9

4.2 Site Applied test sample preparation 10

4.3 Pipes 10

4.4 Pre-treatment of test samples 11


5 Analysis

5.1 Collection and storage of samples for analysis 12

5.2 Procedural spike control samples 13

5.3 Determination of TOC 13

5.4 GC-MS general survey analysis 13

5.5 Determination of specified substances 14

6 Expression of Test Results

6.1 Migration Rates 16

6.2 At Tap Concentrations 16

7 Reporting Requirements

7.1 General 17

7.2 Test water for leachate preparation 17

7.3 Analytical records 18

7.4 Test results 19

Annex A AQC checklist 20

Annex B Analytical performance and estimating uncertainty 22

Bibliography 25



GENERAL DEFINITIONS (for use with all Test Protocols) The relevant regulations (for public drinking water suppliers) The following regulations apply to the approval of substances and products used in the provision of public water supplies within the United Kingdom:

a) England - Regulation 31 of The Water Supply (Water Quality) Regulations 2016 (Statutory Instruments 2016 No 614): http://www.legislation.gov.uk/uksi/2016/614/pdfs/uksi_20160614_en.pdf

b) Wales – Regulation 31 of The Water Supply (Water Quality) Regulations 2016 (Welsh Statutory Instrument 2016 No 410 (W.128)): http://www.legislation.gov.uk/wsi/2016/410/pdfs/wsi_20160410_en.pdf

c) Scotland – Regulation 33 of The Public Water Supplies (Scotland) Regulations 2014 – http://www.legislation.gov.uk/ssi/2014/364/contents/made

d) Northern Ireland – Regulation 30 of The Water Supply (Water Quality) (Amendment) Regulations (Northern Ireland) 2009 (Statutory Rules of Northern Ireland 2009 No.246) - http://www.opsi.gov.uk/sr/sr2009/nisr_20090246_en_1

Where reference is required to specific regulatory requirements, these are given in footnotes.

http://www.legislation.gov.uk/uksi/2016/614/pdfs/uksi_20160614_en.pdf

http://www.legislation.gov.uk/wsi/2016/410/pdfs/wsi_20160410_en.pdf

http://www.legislation.gov.uk/ssi/2014/364/contents/made

http://www.opsi.gov.uk/sr/sr2009/nisr_20090246_en_1



PROCEDURE FOR THE DETERMINATION OF SUBSTANCES LEACHING FROM NON-METALLIC PRODUCTS 0. INTRODUCTION This protocol is intended for the use of designated laboratories testing factory made and site applied non-metallic products. Where possible British and European standard test methods have been referenced and interpretation of the test results are aligned with the 4MS Common Approach. Laboratories are reminded that deviations from the approach given in this document should be discussed and agreed with DWI before testing commences. 1. SCOPE This procedure is used to assess the leaching of substances from non-metallic products such as pipes, tanks and linings and coatings for tanks, reservoirs and pipes. The products may be factory-made or site-applied, i.e. the surface which is in contact with water, is produced on site, together with cementitious products. This Test Protocol is divided into three product type related sections – Section 2. Factory made and applied products – based upon BS EN 12873-1 and BS EN 15768. Section 3. Site applied products – based upon BS EN 12873-2, BS EN 15768 and BS 6920-2.2.1. Section 4. Cementitious products – based upon BS 6920-2.2.1 and BS EN 15768. Both sets of procedures include the following aspects of testing: • preparation and storage of test samples; • pre-treatment of test samples; • preparation of test leachates; • collection of leachate samples for analysis; • determination of total organic carbon (TOC); • identification of organic chemicals by general survey gas chromatography/ mass

spectrometry (GC-MS); • quantitative determination of specific compounds; • analytical quality control; and • calculation and reporting of test results. Where appropriate, references are made to relevant sections of British Standard BS 6920 Suitability of Non-Metallic Products for Use in Contact with Water Intended for Human Consumption with Regard to their Effect on the Quality of Water. Some aspects of the procedures will vary, depending on the type of the product to be tested and/or the material from which it is made. Details of the specific requirements for site-applied products and for cementitious materials are given where appropriate. The Drinking Water Inspectorate (DWI) will specify in writing any particular leaching test conditions to be used and the substances to be monitored.



This Test Protocol is not applicable to products used in water treatment, such as membrane filters, and adsorptive or filter media such as ion exchange resins and activated carbons - see 5 and 6 of this series of Test Protocols.



2. FACTORY MADE PRODUCTS 2.1 Principle. Test leachates are prepared from pre-treated test product samples in accordance with BS EN 12873-1. Samples of the product to be tested are soaked and rinsed and then immersed in, or filled with, test water and maintained at a temperature of 23oC for three sequential leaching periods of 72 hours (cold water use) over a period of 9 days. Portions of the leachate from each leaching period are collected and analysed for TOC, GC-MS general survey for unsuspected substances in accordance with BS EN 15768, and for target substances that have been specified by the DWI. The relevant control and blank samples shall be prepared and analysed at the same time as the samples. The GC-MS general survey provides information about the presence of other organic substances that may have leached from the product and can be extracted and identified under the test conditions used. Two leaching tests, one with chlorinated and one with unchlorinated test water, are normally carried out at the same time. In some cases, especially in the case of large heavy plant, or where large volumes of test water will be required, e.g. test rigs for reverse osmosis membranes, it is acceptable to carry out testing using one water type, followed by testing using the same test rig, but new membrane filter unit, for the other (different) test water type. In each case the appropriate control and blank samples should be prepared and analysed with each sample. Leaching rates are calculated from the estimated concentrations of the substances in the leachates (after corrections for blanks and recoveries, as appropriate). Leaching rates are normalised to a unit of surface area, taking into account the ratio of surface area of the test sample and volume of test water (S/V) and the duration of the leaching period. Leaching rate curves are then constructed for the duration of the test. The test report is assessed by the DWI and its advisers. 2.2 Test sample pre-treatment. Pre-treat test samples in accordance with section 8 of BS EN 12873-1. Where the product Instructions for Use include specific product related instructions for commissioning or special rinsing of the product, these should be undertaken before starting the pre-treatment procedures specified in BS EN 12873-1. Record any additional treatment undertaken and include details of this in the final test laboratory report. 2.3 Leachate preparation Prepare test leachates using the methods specified in BS EN 12873-1 with the following exceptions –

a) unless specifically instructed by the DWI use two types of test water: - unchlorinated test water – clause 5.1.2 of BS EN 12873-1 - chlorinated test water – clause 5.1.3 of BS EN 12873-1 Where a product will only be used in water collection or treatment up-stream of the first point of chlorination, DWI may specify that leachate preparation should be undertaken using test water with no addition of free-chlorine. In this case leachate preparation



shall be undertaken in duplicate, and the Inspectorate may specify that one of the sets of leachates shall be chlorinated before subsequent analysis.

b) do not undertake duplicate testing with each water type. This is not required under the relevant regulations – see Note 1 of clause 9.1.1 of BS EN 12873-1.

The sequence of leachate preparation for products designed for use with cold water applications is set out in Table 1, and the analytical requirements summarised in Table 4. Table 1. Schedule of leaching periods for factory made products (BS EN 12873-1)

Time from start of test

(days)

Leaching Period

Contact Time (hrs)

3 T1 72±1

6 T2 72±1

9 T3 72±1 3. SITE APPLIED PRODUCTS 3.1 Principle. Test leachates are prepared and cured in accordance with BS EN 12873-2:2005. Immediately after curing has been completed (in accordance with the Instructions for Use or DWI requirements), the samples of the product to be tested are soaked, rinsed and then immersed in, or filled with, test water and maintained at a temperature of 23oC for three sequential leaching periods of 72 hours over a period of 9 days. Portions of the leachate from each leaching period are collected and analysed for TOC, GC-MS general survey for unsuspected substances in accordance with BS EN 15768, and for target substances that have been specified by DWI. BS EN 12873-2:2 permits a break during the pre-treatment procedure between completion of sample curing and the start of leachate preparation. This is not acceptable to DWI and no break is permitted during sample preparation and leachate preparation. The GC-MS general survey provides information about the presence of other organic substances that may have leached from the product and can be extracted and identified under the test conditions used. Two leaching tests, one with chlorinated and one with unchlorinated test water, are carried out at the same time. Leaching rates are calculated from the estimated concentrations of the substances in the leachates (after corrections for blanks and recoveries, as appropriate). Leaching rates are normalised to a unit of surface area, taking into account the ratio of surface area of the test sample and volume of test water (S/V) and the duration of the leaching period. Leaching rate curves are then constructed for the duration of the test. The test report is assessed by the DWI and its advisers.



3.2 Test sample pre-treatment. Pre-treat test samples in accordance with section 8 of BS EN 12873-2. Where the product Instructions for Use include specific product related instructions for commissioning or special rinsing of the product, these should be undertaken before starting the pre-treatment procedures specified in BS EN 12873-2. Record any additional treatment undertaken and include details of this in the final test laboratory report. 3.3 Leachate preparation Prepare test leachates using the methods specified in BS EN 12873-2 with the following exceptions –

a) do not introduce a break in the sequence of sample curing and leachate preparation (whilst such a break is accepted in clause 8.1.4 of BS EN 12873-2, it is not acceptable for DWI leachate studies).

b) unless specifically instructed by DWI use two types of test water – • unchlorinated test water – clause 5.2.2 of BS EN 12873-2 • chlorinated test water – clause 5.2.3 of BS EN 12873-2

c) do not undertake the stagnation with disinfection treatment water (clause 8.2.3 of BS EN 12873-2:2005). This is not required under the relevant regulations – see Note 2 of clause 4 of BS 12873-2:2005.

d) do not undertake duplicate testing with each water type. This is not required under the relevant regulations – see Note 1 of clause 9.1.1 of BS EN 12873-2:2005.

The sequence of leachate preparation for products designed for use with cold water applications is set out in Table 2, and the analytical requirements summarised in Table 4. Table 2. Schedule of leaching periods for site applied products (BS EN 12873-2)


(days)

Leaching Period Contact Time (hrs)

3 T1 72±1

6 T2 72±1

9 T3 72±1

4. CEMENTITIOUS PRODUCTS. Pending the completion of EN standards covering the preparation of leachates from cementitious products, the following procedures shall be used for both factory made or site applied polymer modified cementitious coatings, repair materials, and other related products. 4.1. Principle a. Factory made cementitious products Test leachates are prepared from pre-treated test product samples in accordance with BS EN 12873-1. Samples of the product to be tested are soaked, rinsed and pre-conditioned in accordance with 4.4 of this test protocol. They are then immersed in, or filled with, test water and maintained at a temperature of 23oC for three sequential leaching periods of 72 hours (cold water use) over a period of 9 days. Portions of the leachate from each leaching period are collected and analysed for TOC, GC-MS general survey for unsuspected substances in accordance with BS EN 15768, and for target substances that have been specified by DWI.



b. Site applied cementitious products Test leachates are prepared and cured in accordance with BS EN 12873-2. Immediately after curing has been completed (in accordance with the Instructions for Use or DWI requirements), the samples of the product are pre-conditioned in accordance with 4.5 of this test protocol. They are then soaked and rinsed and then immersed in, or filled with, test water and maintained at a temperature of 23oC for three sequential leaching periods of 72 hours (cold water use) over a period of 9 days. Portions of the leachate from each leaching period are collected and analysed for TOC, GC-MS general survey for unsuspected substances in accordance with BS EN 15768, and for target substances that have been specified by the DWI. Clause 8.1.4 of BS EN 12873-2:2005 permits a break between completion of sample curing and the start of leachate preparation. This is not acceptable to DWI and no break is permitted during sample preparation and leachate preparation. c. Leachate analysis The GC-MS general survey provides information about the presence of other organic substances that may have leached from the product and can be extracted and identified under the test conditions used. Two leaching tests, one with chlorinated and one with unchlorinated test water, are carried out at the same time. Leaching rates are calculated from the estimated concentrations of the substances in the leachates (after corrections for blanks and recoveries, as appropriate). Leaching rates are normalised to a unit of surface area, taking into account the ratio of surface area of the test sample and volume of test water (S/V) and the duration of the leaching period. Leaching rate curves are then constructed for the duration of the test. The test report is assessed by the DWI and its advisers. 4.2 Site Applied test sample preparation The preparation, shape, size and storage of the test sample will depend on the type of product, the material from which it is made and its method of testing. Prepare, cure test samples in accordance with BS EN 12873-2 and in accordance with the Instructions for Use or DWI requirements. Pre-condition samples in accordance with 4.4.2 of this test protocol. Start leachate preparation immediately after curing and pre-conditioning is completed. 4.3 Pipes 4.3.1 Preparation Leaching tests on cementitious coated pipes shall be carried out by filling the pipes with test water. Test the pipe that has the smallest diameter for which approval is sought. Details on the preparation of test samples of pipes are given in Clause A.4.3.1 and A.4.3.2 of BS EN 15768 . 4.3.2 Curing and Storage Depending on the type of pipe and pipe lining, cure and store the test samples as given in the relevant Sections 3.1 to 3.3. To prevent contamination, insert stoppers or cover the pipe ends with aluminium foil or plates made of inert material, e.g. PTFE, stainless steel or glass.



4.3.3 Surface area to volume ratio requirements The S/V ratio for pipes with internal diameter of 100 mm or less is determined by the internal diameter of the pipe. When pipes of smaller diameters are not available, pipes with internal diameter above 100 mm may be used as test samples. The S/V ratio may then be increased to about 1 cm2 cm-3 (and not less than 0.4 cm2 cm-3) by using one of the test sample designs given in Annex B of BS EN 12873-1. 4.4 Pre-treatment of test samples 4.4.1 General Rinse the test samples with laboratory tap water for 60 minutes at a flow rate giving a total volume of the rinse water equivalent to 40 ± 2 volumes of test water in contact with the test sample during each leaching period. Where the product Instructions for Use include specific product related instructions for commissioning or special rinsing of the product, these should be undertaken before starting the rinsing specified above. Record details of this additional treatment and include these in the final test laboratory report. 4.4.2 Pre-conditioning Soak test samples as described in clause 6.14.1.3 of BS 6920-2.1, except that for pre-conditioning, irrespective of the pH in the third soak water, limit the sequential 24 hours soak periods in contact with non-aggressive water to three. Adjust the volume of the soak tap water according to the total surface area of the test sample so that the S/V ratio is the same as for the leaching test (Section 4.5). Measure the pH of the soak water at the end of each of the three contact periods with the test pieces and record the information, together with the characteristics of the soak tap water, i.e. alkalinity, hardness and aggressivity (see clause 6.14.1.3 of BS6920-2.1). At this stage samples may be stored in accordance with clause 7.8.2.3 of BS 6920-2.1. Rinse the cementitious product test samples in accordance with 3.5.1. 4.5 Leachate preparation Prepare test leachates using the methods specified in BS EN 12873-2 with the following exceptions:

a) for site-applied cementitious products do not introduce a break in the sequence of sample curing, pre-conditioning and leachate preparation (whilst such a break is accepted in clause 8.1.5 of BS EN 12873-2, it is not acceptable for DWI leachate studies).

b) unless specifically instructed by DWI use two types of test water: • unchlorinated test water – clause 5.1.2 of BS EN 12873-1 or 2 • chlorinated test water – clause 5.1.3 of BS EN 12873-1 or 2

c) do not undertake the stagnation with disinfection treatment water (clause 8.2.3 of BS EN 12873-1 or 2). This is not required under the relevant regulations – see Note 2 of clause 4 of BS 12873-1 or 2.

d) do not undertake duplicate testing with each water type. This is not required under the relevant regulations – see Note 1 of clause 9.1.1 of BS EN 12873-1 or 2.



The sequence of leachate preparation for products designed for use with cold water applications is set out in Table 3, and the analytical requirements summarised in Table 4. Table 3. Schedule of leaching periods for cementitious products (BS EN 12873-1 & 2)


(days)

Leaching

Period

Contact Time (hrs)

3 T1 72±1

6 T2 72±1

9 T3 72±1

5. ANALYSIS 5.1 Collection and storage of samples for analysis Collect appropriate samples for analysis, making use of schedules shown in tables 1-3, whilst undertaking analysis in accordance with table 4. Table 4. Sampling schedule and analytical requirements (BS EN 12873-1 & 2). Leaching Leachate Procedural blank Spiked procedural control

Period no chlorine chlorinated no chlorine Chlorinated

T1 SD/TOC/GCMS SD/TOC/GCMS SD/TOC/GCMS SD/TOC/GCMS

As specified in clause 5.2 of this test protocol

T2 SD/TOC/GCMS SD/TOC/GCMS SD/TOC/GCMS SD/TOC/GCMS

T3 SD/TOC/GCMS SD/TOC/GCMS SD/TOC/GCMS SD/TOC/GCMS SD = specific substances; GCMS = general survey GC-MS analysis Totals: SD/TOC/GCMS 12 determinations (6 leachates and 6 procedural blank controls) Sampling volumes, sampling vessels, methods of preservation and methods of storage will be governed by the analytical requirements. The requirements of samples for general survey GC-MS are given in BS EN 15768. For TOC analysis, completely fill a suitable bottle with a portion of the leachate or procedural control sample, so that there is no headspace above the sample. Seal the bottle with a glass stopper or an inert screw cap, store at (4±2)°C and analyse within one week. When collecting samples prepared with chlorinated test water remove the residual chlorine by the addition of a solution of sodium thiosulphate solution or ascorbic acid solution. Note: ascorbic acid is not suitable for dechlorinating test samples for TOC analysis. Normally, aqueous samples for the determination of organic compounds shall be tested within 48 hours of collection unless the stability of the appropriate substance has been established during the validation of the analytical method; in this case extract the test leachate(s) before any deterioration occurs.



5.2 Procedural spiked control samples During the stagnation period the concentration of some substances of interest arising from the test sample could be reduced by e.g. adsorption on the test vessel, volatilisation, or by reaction with chlorine. Spiked procedural controls therefore need to be prepared and analysed in order to assess the significance of any such losses. Prepare procedural blanks in accordance with the appropriate test method, including an appropriate surface area of any material in contact with the test water, which is not derived from the test sample. Half-fill the stoppered glass bottle. Add to the bottle a solution of the substance(s) of interest in a water soluble organic solvent (normally methanol) and then fill the bottle with more test water. The prepared concentration of each substance in the spiked sample should normally be 10 to 20 µg l-1 (50 to 100 µg l-1 when testing site-applied pipe linings). When the leaching test is carried out in a pipe, procedural blank samples should be kept in stoppered glass bottles in the dark. As a minimum requirement, for frequently measured substances for which no significant losses occurred during previous tests, prepare one procedural spiked sample with test water and another with chlorinated test water with leachates from one of the 72-hours stagnation periods. For substances that have not been measured before and substances that are known to be subject to potential losses during the stagnation periods, more frequent procedural spiked samples will need to be prepared and analysed. More frequent procedural spikes are also needed when substances are determined using an analytical method with poor accuracy. Note: The required frequency of the additional procedural spiked samples will increase with decreasing accuracy of the analytical results and with increasing variation in the losses of the substance during the stagnation periods. 5.3 Determination of TOC The method shall be capable of detecting 0.1 mg C l-1 with a relative standard deviation of 10%. The AQC procedure shall include the analysis of at least two spiked AQC samples with each batch of samples from the test and the results should be included in the report. Note: samples should be analysed in accordance with a standard analytical method, e.g. the method described in BS EN 1484:1997. 5.4 GC-MS General Survey analysis Analyse test leachates in accordance with BS EN 15768. Methods of expressing the results, i.e. the identification and quantification of compounds detected and quality control procedures are given in BS EN 15768. The performance of the method is considered acceptable providing that:

a) all of the 9 specified internal standards, which have been added to the aqueous sample are detected in the GC-MS total ion chromatogram (TIC); and b) the recoveries of the internal standards d8-naphthalene, d10-phenanthrene and d62-squalane are above 50%.

Levels of background contamination in procedural blanks should be as low as practicably possible and should not interfere with the identification or qualification of any substances identified as coming from the test sample. Every effort should be made to obtain “clean”



solvents, but where contamination of the solvent is high and unavoidable, additional measures will be required to establish the adequacy of the analysis. 5.5 Determination of specified substances 5.5.1 General Concentrations in the leachates may vary from >1 mg l-1 (for site-applied products, at the beginning of the test) to <1 µg l-1. Generally the analytical methods should be capable of detecting 1 µg l-1 of each substance. The DWI may accept methods with higher limits of detection (LoD) when the concentrations are at least 5 to 10 times higher than the LoD in all leachates or where achievement of the target LoD of 1 µg l-1 is not practicable. NOTE. If the target LoD cannot be achieved the DWI should be consulted before commencing the leaching test. For the set of substances specified by DWI (for each product to be tested) the testing laboratory may select any of the following: a substance specific analytical method, a multi-residue method or a combination of methods capable of the selectivity, sensitivity and/or accuracy required. More than one analytical method may be required for determination of the same substance where the concentration in the leachates decreases by several orders of magnitude during the leaching test. Evidence (from testing) of the performance of analytical methods shall be included in the report. The required evidence will depend on the previous uses of method(s) by the laboratory, i.e. whether the method is: used routinely, been validated and used before, or it is a new method. In order to provide the DWI with acceptably accurate, leaching data , decisions on the selection of the appropriate analytical methods and the extent of the validation and analytical quality control (AQC) shall be made by a responsible laboratory analyst, with experience in the determination of organic substances at low concentrations. 5.5.2 Analytical Quality Control 5.5.2.1 Routine analytical methods Routine analytical methods, for example, for the determination of metals or volatile organochlorine compounds, shall have established AQC procedures. The AQC procedure shall include the analysis of at least two spiked AQC samples with each batch of samples from the test, and the results from this analysis shall be included in the report. The concentrations of the spiked AQC samples shall correspond with the product leachate data. For example, when ‘not detected’ (i.e. less than 1 µg l-1) concentrations in the product’s leachates are reported, the AQC data shall be provided in the concentration range of 1 to 10 µg l-1 . In the case of unexpectedly high concentrations of the substance in the leachates, additional spiked AQC samples of comparable concentration shall be prepared and analysed in the same manner as the leachates. 5.5.2.2 Validated analytical methods Substances for which the analytical method has been satisfactorily validated during previous tests (such as common antioxidants or bisphenols A and F diglycidyl ethers), no further preliminary validation is required. The number of AQC blank and spiked samples to be included with the test samples will depend on the known performance of the analytical method. As a minimum requirement the following AQC samples shall be prepared and analysed:



• duplicate analytical method AQC blank samples, using test water (5.1), on two separate occasions

• duplicate AQC spiked samples, using test water, on two separate occasions at low concentration (5 to 10 times above LoD of the analytical method)

• duplicate AQC spiked samples on one occasion at high concentration (50 to 100 times above LoD of the analytical method)

• in case of unexpectedly high concentrations of the substance in the leachates, additional spiked AQC samples of comparable concentration shall be prepared and analysed in the same manner as the leachates.

The above AQC should be adequate for specific methods such as selective ion monitoring (SIM) GC-MS when using an internal standard. More control samples will be needed for methods such as high performance liquid chromatography with ultra violet detection (HPLC UV) or gas chromatography with flame ionisation detection (GC FID), particularly when derivatisation is involved. All AQC sample results shall be included in the report together with information on the concentration range, for which the method has been calibrated. The data shall be reported in both table and chart formats. 5.5.2.3 New analytical methods Substances for which the test laboratory does not have satisfactory validation data, preliminary validation shall be carried out before the start of the leaching tests, and the results shall be included in the report. The main objectives of the validation are to check that -

• the substance would be detected if present at the lowest concentration of interest • the recovery (where appropriate) is adequately high and consistent over the

concentration range of interest • the method does not suffer from serious interferences • the substance is stable under the conditions and over the intended period of storage

between sampling and analysis. As a minimum requirement prepare a batch consisting of duplicate analytical method blank samples (using test water), along with duplicate samples of test water spiked at the lowest concentration of interest and duplicate spiked samples at the maximum expected concentration. Analyse these samples using the analytical method intended for the analysis of samples from the leaching tests. For substances from site applied tests at least three concentration levels should be analysed because the concentrations in the leachates could change from >1 mg l-1 to < 10 µg l-1 over the period of the leaching test. If the aqueous samples from the leaching tests are not to be processed on the day of sampling, estimate the stability of the substances during storage. As a minimum, prepare two further duplicate spiked samples at concentrations of 20 to 50 times above the LoD- one duplicate in test water and the other in chlorinated test water. De-chlorinate the latter, using the selected procedure and store all four samples under the conditions to be used for the test samples before the analysis. If any of the above objectives is not satisfied, then the analytical method needs to be modified, or a different method selected, and the validation procedure repeated.



Provided that the results of the preliminary validation are satisfactory or where a new substance is analysed using a method that is well established for a similar substance, the minimum requirements for AQC during the leaching test (as described above for validated analytical methods) shall be sufficient for some simple new methods. Normally, however, for a new analytical method at least one AQC blank and at least one AQC spiked sample should be analysed with each batch of samples from the leaching test. Results for the AQC samples analysed with samples from the leaching tests shall be included in the report together with information on the concentration range for which the method has been calibrated. NOTE General guidance on the analytical performance requirements such as detection limit and accuracy is contained in DD ENV ISO 13530. 6. EXPRESSION OF TEST RESULTS The concentrations measured in samples from the tests shall be corrected for blanks and adjusted for recoveries, as appropriate. Any calculations, and the values used to arrive at the reported concentrations, shall be included in the report. Results for the spiked procedural controls shall be treated in the same way as those for the leachates, including any corrections for blanks and/or recoveries. 6.1 Migration Rates The normalised leaching rate Mn (migration rate) for the stagnation period n is calculated using equation 1: Mn = cn / ( S / V x t) µg dm-2 day-1 (1) where: cn = concentration in the leachate i ( µg l-1), corrected for blank and recoveries S = surface area of the test sample in contact with 1 litre of test water (normally 10 dm2), V = volume of water in contact with the test sample, t = duration of the stagnation period (days). The calculated normalised leaching rates represent average leaching rates for the period between the start and the end of each stagnation period. The values should be plotted against the time of the test. 6.2 At Tap Concentrations Migration rate shall be used to calculate “at tap” concentrations using the principles laid down in the Positive Lists for Organic Materials, 4MS Common Approach, Part B – Assessment of products for compliance with Positive List requirements (Conversion Factors - CFs) Section 5. The use of the standardised conversion factors CF allows the DWI (and other members of the 4MS) to use leaching test results to produce a measure of actual human exposure to chemicals derived from materials in contact with water and to compare the exposure with toxicological information to assess the risks posed by the product tested. Conversion Factors (CF) are given in Table 1 of the Common Approach document and are based on the surface area of a product under normal use, the volume of water the product is in contact with and the length of time that water is in contact with the product. Hence:



CF = ( S / V ) x t days dm-1

Where S is the surface area of a product under normal use, V is the volume of water the product is in contact with under normal use, and T is the length of time that water is in contact with the product under normal use. Therefore the “at tap” concentration CTap can be calculated as: CTap = Mn x CF µg l-1 The calculated “at tap” concentrations for the sequential leaching periods (in µg/l) shall be shown in the report in a table and in a graph plotted against time. 7. REPORTING REQUIREMENTS Note: general reporting requirements are given in Protocol 1 of this series. Submit the results of testing in the following formats:

a. an electronic report (MS Word or Adobe Acrobat PDF file format), including all the information set out in Protocol 1 (and below), with the exception of chromatograms, charts and computerised analytical print-outs; this report will be made available to DWI members

b. a full, signed and dated report, including all supporting chromatograms, charts and computerised analytical print-outs; this report will be made available to the DWI’s advisors. Wherever possible, please submit this final report electronically (MS Word or Adobe Acrobat PDF file format).

With each signed and dated report (including electronic versions), include a completed copy of the AQC checklist – see Annex A. Ensure that all relevant analytical performance and uncertainty data (see Annex B) are included in each report. The test report shall include the following particulars: 7.1 General

a. a reference to the written leaching test specification from the DWI; b. a reference to this document; c. details of any amendments to the above, requested in writing by the DWI; d. any deviations the test laboratory has made to the test protocol; information in

accordance with the requirements of the standard. e. the identity of the production batch of the test samples f. details of actual temperatures, relative humidity and duration of curing g. a chain of custody if test samples have been prepared by a third party or off-site.

7.2 Test water for leachate preparation

a. nature and source of the test water, including method(s) of preparation b. analytical results for the specific test water used for the leachate preparation

demonstrating conformity with the requirements of Clause 5.1 (Water to be used for testing) of BS EN 12873-1, including conductivity and TOC.

7.3 Analytical records



7.3.1 For all substances: a. dates of extraction of analytical samples from the tests (where relevant) b. dates of analysis of samples from the tests c. source of the standard or reference material d. the limit of detection of each method, basis of its estimation and results for analytical

method AQC blank samples analysed with the batches of the leaching test samples e. any recovery factors used in the calculation of the reported analytical results and basis

of their estimation; f. estimates of the accuracy of the analytical results over the range of concentrations of

interest and basis of their estimation g. results for AQC spiked samples analysed with the batches of the leaching test samples h. details of the treatment of the samples and/or the results where the concentration of the

substance was outside the calibrated range of the analytical method. i. No information shall be included in the report that would allow any possible identification

of anonymised compounds. Where necessary, submit this information, in confidence, separately to the Inspectorate (see Section 1.7 of Test Protocol 1).

In addition to a) to h) above the following information shall be provided:

7.3.2 For routine analytical methods: a. outline of the analytical method and reference to a written procedure b. principles of routine AQC in operation.

7.3.3 For validated analytical methods

a. outline of the analytical method and reference to a written procedure; b. estimates of the method performance based on data from previous tests and the basis of

the estimates; c. a description of the standards and calibration procedures used for the analysis of the

batches of samples from the leaching test d. calibration curves.

7.3.4 For new analytical methods

a. a full description of the analytical method used b. description of the preliminary performance testing including the results and assessment

of the performance of the analytical method c. a description of the standards and calibration procedures used for the analysis of the

batches of samples from the leaching test d. calibration curves.

7.3.5 General survey GC-MS analysis

a. an outline of the analytical method with references to the appropriate sections of BS EN 15768.

b. information in accordance with the requirements listed in BS EN 15768 c. assessment of the internal standards in test samples in relation to the criteria of

acceptance of the method performance (see Section 9) d. assessment of quality of procedural and laboratory blank samples in relation to

compliance with the target set by the DWI (see Section 9) 7.4 Test results 7.4.1 For specified substances and TOC



a. concentrations found in the leachates (corrected for blanks and recoveries, as appropriate), as well as results for procedural blanks and procedural spiked control samples (µg l-1)

b. normalised daily leaching (migration) rates calculated for all leachates (see Section 11.11)

c. for each substance, leaching rate curves over the period of the test (for both tests, with test water and with chlorinated test water)

d. for each substance, illustrative chromatograms (GC, GC-MS, HPLC, LC-MS, MS-MS etc.) for a standard solution, procedural blank samples, AQC spiked controls and leachates (e.g. from the first leaching period, with test water and with chlorinated test water).

e. No information shall be included in the report that would allow any possible identification of anonymised compounds. Where necessary, submit this information, in confidence, separately to the Inspectorate (see Section 1.7 of Test Protocol 1).

7.4.2 For the GC-MS General survey Report the results in accordance with BS EN 15768.



ANNEX A (Normative)

AQC Checklist

Guidance on Completing the AQC Checklist. Please ensure that all relevant sections are completed, including relevant comments and confirmatory evidence for each category – these comments should refer to the appropriate section(s) and page number(s) of the test report.



TEST LABORATORY: REPORT REF: ISSUED:

PRODUCT: DWI REF: 56.4.

We confirm that this report conforms with the appropriate requirements as set out below. Date:

AQC checklist Limits BS EN 12873 Clause

Test Protocols

Comment or confirmatory reference

Test conditions

Cementitious material, area tested 15 000 mm²

Ratio of surface area to volume is close to 1 cm²/cm³ > 0.4 cm²/cm³ 2: 3.1

The test water is RO or distilled of low conductivity EC < 20µS/cm

The test water has low TOC < 0.2mg/l

Chlorinated test water with a free chlorine concentration 1±0.2 mg/l

AQC general

There is an outline of the analytical method † 2: 5.5.2

Established methods have validated performance data † 2: 5.5.2.2

New methods have a preliminary performance data 2: 5.5.2.3

Calibration procedures and curves are provided 2: 7.2

There are two samples spiked at low level with each batch 2: 5.5.2

Performance of GC-MS system

Method validation for the GC-MS and description † 11.2

Limit of detection for the deuterated standards and their derivation † 11.2

The internal standards in the GC test solution are not saturated

GC-MS can resolve a difference in m/z of 1 at highest mass resolution 650

The temperature ramp is not too fast < 12 ºC/min

Benzene is separated from the solvent

The RT for squalane is within spec. 35 - 45 min

All internal standards are detected in the TIC chromatogram 9 standards 9.3 Recoveries for deuterated naphthalene, phenanthrene & squalane are satisfactory >50 % 9.3

Intensity of internal standards in the test solution is close to the set up values within 30 % 8.3 The absolute values of the deuterated standards are tabulated and graphically plotted

Asymmetry factors of phenol & naphthalene peaks in the test solution are satisfactory 0.67 - 2.0 8.3

Mass calibration is satisfactory, or the spectrometer has been recalibrated 9.1

There is an AQC standard every 6 samples

Reporting GC-MS An annotated TIC chromatogram of the GC test solution for each analytical occasion 11.2

An annotated TIC chromatogram for each solvent extract 11.2

The basis on which peaks are identified is described † 11.2 All peaks on the TIC chromatogram with a peak area >50% of naphthalene have a retention time or scan no. cross-referenced to its MS scan 10.3, 11.2

Each compound detected is identified positively, tentatively or if unknown or no identification, with the four largest MS peaks listed 10.3, 11.2

Each compound detected is quantified by reference to the appropriate internal standard 10.1

Conversion factor for migration rates is recorded Indications of the origin of all peaks considered not to originate from the test piece 11.2

A mass spectrum of each compound originating from the test piece, along with the corresponding nearest matching library spectrum 11.2

Chlorine

Chlorine demand

Chlorine AQC †

TOC

The method is sensitive † lod ≤ 0.1 mg/l 2: 5.3

The method is precise, with a standard deviation of <0.1 mg/l or rsd < 10% † rsd < 10% 2: 5.3

TOC control chart † and results of AQC standards for the batches reported † The DWI will accept reference to a separate report, so long as they are provided with a controlled copy that is less than 5 years old and subject to annual review



ANNEX B (Normative)

ANALYTICAL PERFORMANCE AND ESTIMATING UNCERTAINTY B.1 ANALYTICAL PERFORMANCE The performance of an analytical method should be characterised by four measures:

• precision • bias • limit of detection • recovery

The precision and bias should be estimated over the range of the analysis. When a method is first introduced it must be validated, e.g. the laboratory must demonstrate that the performance is acceptable by estimating these four parameters. Thereafter, confirmation of this performance must be demonstrated in routine analysis. This is commonly achieved by analysing an AQC standard with every batch of samples and plotting the result on a control chart. There have been many ways of calculating these parameters, but the DWI requires them to be estimated in conformity with ENV ISO 13530. The following notes briefly describe what is expected. B.2 PRECISION The random error, also called precision, is characterised by the standard deviation of an analytical result. This will have been estimated during validation of the method, but the best value for estimating the uncertainty of a particular result is probably the standard deviation of the AQC standard. It will:

• be representative of current work • will have many degrees of freedom • include all sources of variance within the laboratory

In any event, there should be at least 10 degrees of freedom and ideally the precision should be estimated at a concentration close to the reported values. B.3 BIAS The systematic error or trueness is the difference between a result and the true value. This should be reduced to zero when setting up the method by taking account of interference and matrix effects, but inevitably some residual is left. The precision will indicate whether this is an insignificant amount. B.4 LIMIT OF DETECTION The smallest amount of determinand that can be quantified with an acceptable precision is calculated from the within batch variance of replicated determinations of a blank. If this is zero, an estimate of within batch variance of a solution with a low concentration should be used. The formula is: 2 × √2 × t0.05 × Sw (or 4.653 × Sw for large degrees of freedom) where: t0.05 is the single sided value of Student’s t, and Sw is the within batch standard deviation of blanks.



B.5 RECOVERY The recovery should be calculated from the difference between spiked and unspiked samples. It is usually expressed as a percentage and calculated as the quotient of the mean of the amounts recovered from a number of tests and the amount spiked. B.6 CONTROL CHART The DWI expects reports to contain evidence that the batches of samples were analysed satisfactorily. This usually takes the form of the results of the AQC standards and a section of the control chart. B.7 ESTIMATING UNCERTAINTY The parameters of analytical method, of course, only quantify the sources of variances within the analytical laboratory. There are likely to be significant variances arising from the choice of sample to test (representative of the production), how it is kept before starting the leaching tests and the leaching process itself. In most cases the DWI requires the combined uncertainty, not an expanded uncertainty. The DWI needs an estimate of the uncertainty in the concentrations of leachates and hence the migration rates of contaminants into the water supply. External sources of uncertainty can be ‘added’ to the analytical precision to produce a combined uncertainty as described in the Eurachem Guide. This is the method UKAS expect accredited laboratories to employ when conforming with ISO/IEC 17025, although other schemes would be acceptable in particular circumstances. Each test is different, but an example is set out below. Example: TOC Suppose TOC can be measured with a precision of 0.05 mg/l at 2mg/l. The value used to estimate the leaching rate is likely to be blank corrected, i.e. the difference between two determinations. In table 1 are suggested values (as standard deviations of a Gaussian distribution) for the sources of variation. Table 1.

Source of uncertainty s.d. unit The test piece is a representative sample of the production 5 % Measurement of the size of test piece 1 % Variation in leachate preparation 2 % Test piece storage between selection and leaching 5 % Test piece transportation 1 % Precision of analytical measurement 0.05 mg/l Allowance for blank correction, or calculation of change 0.05 mg/l

In this example, if the measured concentration is 2mg/l and the procedural blank is 0.1, the combined uncertainty will be 0.17mg/l, or 8.6%. This is over three times as much as 0.05, the precision of a single analytical measurement. It is instructive to investigate the relative contribution made by each source of uncertainty (figure 1). Note that the analytical laboratory only accounts for 26% of the combined uncertainty, roughly the same as the choice of a representative item from the production line and of its subsequent storage.



Figure 1.

Whilst some of the variances in table 1 have been measured, others are estimates based on experience. Calculation of the variance from measurements should be used wherever possible.



BIBLIOGRAPHY BS EN 1420-1:2016 Influence of organic materials on water intended for human

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BS EN 1484:1997 Water analysis – Guidelines for the determination of total organic carbon (TOC) and dissolved organic carbon (DOC)

BS 3900:Part C5:1992, ISO 2808:1991

Methods of test for paints. Tests associated with paint film formation. Determination of film thickness

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Suitability of non-metallic products for use in contact with water intended for human consumption with regard to their effect on the quality of the water —

Part 4: Method for the GC-MS identification of water leachable organic substances

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Part 2: Test method for non-metallic and non-cementitious site-applied materials

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General requirements for the competence of testing and calibration laboratories

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Documents

P otocol 2 N m P ducts Ge methods · 2020. 11. 26. · Pre-treat test samples in accordance with section 8 of BS EN 12873-1. Where the product Instructions for Use include specific