8. Storing samples in a way the preserves the integrity of the sample. 9. Transportation of the samples to a laboratory for off-site analysis

Transcription

1 Sampling Contents 1. An introduction to the science and art of sampling 2. Design of a sampling programme 3. Development of a sampling manual 4. Physically taking samples according to the sampling programme in the ways specified in the sampling manual 5. Sampling for physical and chemical parameters 6. Analysing samples on-site for specific parameters 7. Microbiological sampling 8. Storing samples in a way the preserves the integrity of the sample 9. Transportation of the samples to a laboratory for off-site analysis 10. Recording results of sampling 11. Additional Resources Annex A Best Practice: Operational Monitoring Requirements Annex B Draft Sampling Manual Annex C Example Field Log Sheet Annex D Sampling Taps Annex E The Provincial Laboratory for Public Health (ProvLab) Annex F References Page 1 of 40

2 1. An introduction to the science and art of sampling The production of drinking water (also known as potable water from the Latin potabilis meaning 'to drink'), relies on a complex series of interactions between the natural environment (the source of the drinking water) and the man-made environment (the systems developed to collect the raw water; the treatment of the raw water into potable water; the distribution system that conveys the treated water to consumers and the plumbing system inside an individual consumer's premises from where they take the water for consumption). The regulatory system that controls all these various elements relies on several "pillars" to ensure the drinking water being supplied meets the health-based quality targets that are specified in the regulations. Some of these "pillars" relate to specifying what treatment processes need to be used for certain types of source waters; some specify how individual unit treatment processes need to be engineered and operated; some specify the quality of the materials or chemicals used in treatment systems or piping or plumbing systems. There is one regulatory "pillar" that stands out above all others and that pillar relies on the testing of the quality of the final product that is being consumed by the people served by the drinking water systems (the municipal waterworks system as the regulations term it). This "end-of-pipe" testing measures a variety of parameters in the drinking water (chemical, microbiological, physical) against pre-determined quality standards which are derived to protect public health - the production of drinking water is, in reality, a public health activity after all. To determine if the drinking water meets the required quality standards, samples of the drinking water need to be taken and analysed either at the time of sampling (like chlorine residual) or in a laboratory specifically designed to undertake these specialised tests (like the bacteriological testing of drinking water for pathogenic bacteria). Most of us will have flown in a commercial aircraft at some point in our lives. We line-up to check-in; we line-up to go through security; we line-up to board the aircraft. Once on board we settle down to enjoy the flight and will munch on the snacks or have a drink while watching the on-board entertainment system until we are told to fold away our tray tables and put our seats in the upright position in preparation for landing. No matter how long or short the flight has been we will judge the competence of our pilot on one single event - how hard the wheels make contact with the runway on landing. A gentle touchdown will make us think of the pilot as an expert; a heavy, jolting landing will make us think poorly of the pilot. It doesn't matter how much preparation the pilot has made hours before we even checked-in; the years spent in training; how many potential in-flight disasters have been averted; our sole point of judgement is how hard that landing has been. The same is true for your regulatory samples - the preparation and operation of the treatment system; the years of training and experience; the disasters averted - all these count for nothing if your samples fail to meet the regulatory requirements set out for the system. Fairly, or unfairly, most of your customers (and your regulator) will judge you on the quality of the samples - good samples are your gentle landing; failed samples are you hitting Page 2 of 40

3 that runway hard enough to pop open a few overhead bins. Sampling is not just filling a bottle with water and sending it to the lab. Sampling is one of the key tasks you will undertake as an operator and one of the tasks least understood by anyone outside the drinking water community. Sampling is part of the science that controls the quality of drinking water and through the act of taking a drinking water sample you are the start and finishing point of a highly complex, technologically dazzling series of processes that almost defy belief. Yet sampling is also an art - it requires patience, careful preparation, diligent action and a complete immersion in the task at hand. Never believe anyone who tells you that sampling is easy - they have clearly never sampled, or if they have, they probably haven't been doing it properly. "Sampling" is actually a short-hand or jargon term that covers a whole list of activities: a) Design of a sampling programme b) Development of a sampling manual c) Physically taking samples according to the sampling programme in the ways specified in the sampling manual d) Sampling for physical and chemical parameters e) Analysing the samples on-site for specific parameters f) Microbiological sampling g) Storing samples in a way the preserves the integrity of the sample h) Transportation of the samples to a laboratory or laboratories off-site for analysis i) Receipt of results from either on-site or off-site testing j) Recording results of sampling We will look at each of these activities in turn. 2. Design of a sampling programme i Drinking water sampling programme strategies and designs can typically be considered as either 'directive' or 'probabilistic'. Directive sampling strategies are based on instructions laid out in approvals, Code of Practice, regulations or other legally-binding documents. This approach is used when there is an understanding of the system and its anticipated characteristics and is also referred to as the 'compliance' sampling programme. A probabilistic approach, when applied to drinking water systems, is used as an investigative tool to determine the source and/or extent of possible contamination of an area. This approach relies on field experience, historical documentation and knowledge of the behaviours of the contaminant under specific environmental conditions. Page 3 of 40

4 A drinking water system should also, whenever possible, have a pre-determined 'operational' sampling programme to check the quality of the raw water, the effectiveness of water treatment and the quality of water leaving the treatment works and/or service reservoirs/water towers that is not adequately covered by the compliance sampling programme. This 'best practice approach' should set out the number of samples to be taken for each parameter, the points at which the samples are to be taken and when the samples are to be taken. 3. Development of a sampling manual It is important to have a manual that sets out all the procedures and precautions that samplers should take for every aspect of the sampling process. A draft sampling manual has been provided as Annex A to this text. This draft will still require the operator to insert specific information (highlighted in the manual) that fits in with their own system and work arrangements. You can, of course, develop your own sampling manual and the following provides some guidance on what a sampling manual should include. As a minimum the sampling manual should contain information on the following ii : (i) the procedures and precautions to be taken when sampling for each parameter or groups of parameters; (ii) the pre-determined compliance sampling programme which may include taking samples from distribution; (iii) any pre-determined operational sampling programme to check the effectiveness of water treatment and the quality of water leaving the treatment works which is not covered by the compliance programme in (b) above; and (iv) any appropriate raw water sampling programme to enable the correct treatment to be applied and adjustments of treatment processes to be made when there are changes in raw water quality. Annex B provides some additional guidance on the development of operational sampling requirements for inclusion in the sampling manual. In conjunction with your laboratory service provider (for analysis of chemical parameters done off-site) or your instrument supplier (for analysis of chemical parameters done on-site such as chlorine residuals), the procedures and precautions to be taken at (i) should include: a) types of bottles/containers/lids; b) cleaning procedures for bottles/containers/lids; Page 4 of 40

5 c) preservatives to be added to bottles; d) type of sample (first draw, flushed etc) and the sequence for taking each sample from the sampling point; e) storage and transport conditions for each type of sample; and f) time allowed before analysis commences. The draft sampling manual provides detailed instructions with respect to microbiological samples using information provided by Alberta Health Services. In general, a sampling manual when discussing microbiological parameters should include details on the following: g) bottle type, bottle closure and bottle shelf life specification; h) method and conditions of bottle and bottle closure sterilization and incorporation of disinfectant neutralizing reagent; i) arrangements to avoid accidental contamination during sampling; j) sequence of taking samples when "non-microbiological" samples are also being taken; k) guidance for selection of taps for sampling (covering water treatment works, service reservoirs, water towers and consumer's taps) and in respect of consumer's taps any features to be avoided (such as tap inserts); l) precautions for sampling from taps at water treatment works, service reservoirs, water towers and in consumer's premises; m) preparation, cleaning, disinfection and flushing of taps for sampling; n) storage and transport conditions and arrangements for cooling/warming samples; o) cleaning of sample boxes; p) time limits for starting sample analysis; and q) arrangements for keeping samples cool in the laboratory if there are delays between receipt and examination. For all samples, the sampler should: r) have a written work list showing all samples to be taken and clearly identifying compliance samples and operational samples; s) have a log sheet that can be filed for record purposes (a specimen field log sheet is given in Annex C); t) record the reasons for postponing or cancelling compliance samples on the log sheet; u) fix securely a sample label with all required information to the sample container; v) record clearly the unique sample number, location (address or location on site), date, time and sampler identification on the log sheet; w) record all on-site measurements and observations at the time they are made on the log sheet and make sure they are associated with the correct samples and containers; and x) for samples to be taken from consumer's taps, the operator (sampler) should show his/her identification or otherwise establish his/her bona fides and should advise the consumer Page 5 of 40

6 that he/she can check the sampler's bona fides by telephoning the utility or municipality administrative offices. All samples should be transported as quickly as practical to the laboratory in a vehicle that, as a minimum, meets the following advice: y) it is clean and has adequate storage facilities for empty sample containers and for containers filled with samples; z) it has provision for keeping samples cool/warm and for cooling/warming samples, when necessary; aa) it is not used for any purpose that might cause contamination of samples; and bb) its interior and cool boxes/refrigerators are regularly cleaned and maintained. 4. Physically taking samples according to the sampling programme in the ways specified in the sampling manual Of principle concern when taking samples is the health and safety of the operator undertaking the sample - if you feel the conditions in which to take a sample are not appropriate then the golden rule is "Don't". Such conditions may be due to the physical state of the location where you have to sample (e.g. flooded treatment works); the nature of the environmental conditions (severe weather) or concern for personal safety due to the presence of other people (e.g. when requesting to gain entry to a property to take a sample). In circumstances where a sampling event is missed for reasons of your health and/or safety then make sure you record the details on the sampling log and in your operational diary. Once you have established that it is safe for you to being the sampling process the next priority is to ensure that all appropriate precautions to avoid contamination of the sample are taken. These will include the following iii : a) use taps that are accessible to users, preferably those intended only for sampling (e.g. in treatment works see Annex D); b) thoroughly wash hands and/or wear disposable gloves iii ; c) do not eat or drink while taking samples iii ; d) do not use reagents that have passed an expiry date or that have an abnormal colour iii ; e) make sure that cold water is used and that the hot tap is shut; f) avoid using single handle taps (flow and temperature), because it is more difficult to make sure the hot water tap is fully shut off; g) use taps located inside a building or in a location protected from wind and weather; h) avoid using outside taps that are used to connect water hoses; Page 6 of 40

7 i) take a water sample that is representative of the drinking water distribution system using a tap that is not connected to an individual water treatment appliance or system (e.g. water softener); j) remove all objects found under the spout, such as vents, screens, rose heads and hoses; if it is impossible to remove them then choose another tap; k) clean the outside and inside of the spout using a clean, single-use piece of cotton and commercial bleach (containing about 5% sodium hypochlorite) for all samples intended for microbiological analysis; l) let the tap run for 5 minutes before taking a sample in order to ensure that the sample is representative of the water in the distribution system; m) make sure water pressure at the tap is reasonable during sampling to avoid splashing and losing preservatives that are inside the sampling containers; n) remove the cap from a sample bottle immediately before sample collection and place the top in a clean/sterile bag or container while the sample is being collected iii ; o) never smoke while taking or transporting samples; p) avoid breathing on samples iii ; q) never take samples immediately after handling fuels, e.g. filling up a truck with gas; r) avoid taking water samples in a bathroom that may contain chemical deodorants whose composition is identical with certain organic compounds that are being measured; s) never use containers of unknown origin to store samples (use only containers provided by your laboratory or recommended by your analytical equipment supplier); t) never rinse laboratory-provided containers containing preservatives required for analyses; u) ensure that containers used for analyses by the people responsible for the distribution system (at sampling sites) are prepared so as to be contaminant free; v) avoid contamination of the outside of sample containers iii ; w) never use metal sampling devices if the analysis is meant to detect trace metals; x) store sampling materials in clean and well ventilated areas; y) ensure that all containers are closed airtight after sampling; z) if possible, cool samples in the refrigerator before sending them (especially during summer); aa) label all sample containers appropriately; bb) properly resister all samples taken using the appropriate forms (sample log sheet; laboratory requisition sheet; etc,); cc) carefully pack samples to avoid breakage or leakage, and use properly labelled shipping containers for adequate handling; dd) conduct business with a trustworthy transportation service for samples to be kept in good condition within the prescribed analytical timeframe. Accurate and complete labelling of samples ensures that the sample's identity is maintained iv. This is very important for sample tracking and data interpretation. Sample containers may have labels affixed to the container itself; alternately the label or sample tag may be provided Page 7 of 40

8 separately and attached to the container after the sample is collected. It is advisable to pre-label all sample containers prior to taking the sample or to label each container immediately after the sample has been taken to prevent confusion. An indelible (permanent) marker or pen should be used and the material from which the label is comprised should be able to withstand water. In most cases, the laboratory conducting the analysis will supply the sampling container. If the tags/labels are separate, the sampler should attach them prior to or immediately after taking the sample to prevent incorrect labelling. The sampling manual should provide guidance on the ordering of samples when more than one type of sample is to be collected. The International Standard (ISO 5667 Water quality - Sampling - Part 5: Guidance on sampling of drinking water from treated works and piped distribution systems iii ) provides the following advice: "The order in which samples are collected should be based on the purpose of the sampling and the potential for cross contamination or other adverse effects on sampling. For example, use of hypochlorite (bleach) solution to disinfect taps may adversely affect samples taken subsequently for trihalomethanes (THMs), chlorinated organics, residual chlorine, polycyclic aromatic hydrocarbons (PAHs) and any other determinand which may be produced, destroyed or changed by oxidation to a form which will not be determined." In other words the hypochlorite can significantly alter substances in the water to make the sample appear to be either failing or passing analyses for certain tests when the actual level may be completely different. Care has to be taken that when different parameters are being sampled that any actions taken by the operator do not adversely affect the integrity of the subsequent result. For routine sampling the following order of taking samples should be followed iii : a) first draw samples e.g. lead, copper; b) flush (if total organic carbon sample required); c) take total organic carbon samples; d) turn off tap; e) clean tap; f) flush g) take all other samples for physical and/or chemical parameters (including samples for onsite tests) in an order designed to minimise cross-contamination of samples by reagents; h) turn off tap; i) disinfect the tap; j) flush the tap; k) take samples for microbiological parameters Page 8 of 40

9 After the initial flush for 2 to 3 minutes (at step (b) or (f) depending on what samples are required to be taken at the sampling location), subsequent flushes should be sufficient to remove any residual cleaning or disinfecting agent and re-establish a steady flow. NOTE - when hypochlorite solution is used for disinfection, it is suggested that free chlorine levels are checked before samples are taken. 5. Sampling for physical and chemical parameters 5.1 General In addition to the advice provided in Section 4, some specific physical and chemical parameters require additional care to be taken when samples are collected. Specific advice on collection techniques, sample containers and sample transport conditions will be provide by the laboratory being used to undertake the analysis e.g. trace organics may require to be taken in ambercoloured glass bottles to prevent photo-destruction of the individual compounds of interest. 5.2 Lead The occurrence of lead in drinking water has been a concern to health authorities for a number of years 1. The latest guidance on what is required for lead sampling can be found on the Health Canada website in the document 'Guidance on Controlling Corrosion in Drinking Water Distribution Systems' v [ ] 6. Analysing samples on-site for specific parameters While it is possible to undertake the analysis of many chemical parameters on-site using field test kits, reference needs to be made to the purpose for which the analysis is being undertaken. If the analysis is for a compliance sample then the requirements set out on the drinking water system's approval conditions or Code of Practice around the analysis and reporting of samples needs to be considered. If the sample is being analysed for operational sampling then there are no regulatory requirements that limit the type of analytical process or method that is utilised, but the operator should satisfy themselves that the results that they obtain are appropriately accurate and precise for their needs. Details of how to undertake specific on-site analyses will be provided by the manufacturer or supplier of the test kit/test method in question and the instruction supplied should be followed precisely. 1 For those with a specific interest in this topic a good reference that sets the historical stage for the developing concern around lead in drinking water is 'The Great Lead Water Pipe Disaster' by Werner Troesken (MIT Press, 2006). Page 9 of 40

10 7. Microbiological sampling 7.1 Sampling water in treatment works and storage tanks/water towers vi In water treatment works and storage tanks/water towers, dedicated sampling taps should be provided on each outlet main and other sampling points. These should be capable of being sterilized by flaming, maintained in a clean state, labelled clearly and used exclusively for sampling. Flaming a metal tap intensely with a blowlamp ensures disinfection of the mouth if the temperature there reaches 80 o C or more. This is not the case if water remains in the heated portion. NOTE: Flaming with a lighter is only superficial (not sufficient) See Annex A for detailed step-by-step instruction on how to complete a microbiological sample. 7.2 Sampling water in the distribution main vii To determine the quality in the distribution main, sample in the distribution main or close to it (usually just after the water meter). Obtain permission from the building owner/occupier to enter the premises to take the sample, having explained the procedure (including the cleaning of the taps) to them. Ensure that no contamination from the outer surface of the tap reaches the sample. Do not sample taps with leaking spindles and avoid mixer taps, if possible. Take out any tap nozzle or other attachment or insert (spanners and pliers should be part of the sampling kit). Scrape off any dirt (scale, slime, grease or other extraneous matter) and fully open and close the tap repeatedly to rinse out the dirt from the tap. Disinfect the tap either by flaming (only if the sample point is a dedicated sample point with a sample tap capable of being flamed) or using a solution of sodium hypochlorite. Annex A provides details on how to disinfect dedicated sample taps and taps used for sampling. Once the tap has been sterilized, allow the water to flow long enough to minimize the influence of the plumbing network inside the building. It is necessary to know the detailed layout of the network (volume of tanks or softeners and retention time) to determine the flush time before sampling. Water temperature stabilization may be monitored to achieve the same effect for the same purpose. If you know the layout of the plumbing network then you can calculate how long you should be flushing the tap to ensure you are drawing water from the main. If we assume that 2 3 minutes of free flow (tap fully open) produces about 20 litres of water we can then calculate the length of time we need to flush based on the pipe volumes by substituting the pipe's radius (r, half the diameter) in the equation πr 2 and multiplying the result by the length of the pipe to the sampling point, then multiplying the second result by five (to give the necessary flushing volume). Page 10 of 40

11 Example viii : For a pipe that is 20mm in diameter and 300mm long: Use πr 2 x length, where r (half the diameter) = 10 mm π x (10) 2 x 300 = 94, litres Convert litres (L) to millilitres (ml) by dividing by , = ml The calculate the volume to flush out x 5 = 471 ml So flush out about 500 ml from the line An alternative method is to measure the temperature of the water emerging from the sampling tap as it is being flushed. The water temperature in the plumbing system inside the premise will be higher than the temperature of the water in the distribution system. Observe the temperature as it falls and once a steady temperature has been achieved you should be confident that you are now drawing water directly from the distribution main and not water that has been sitting in the internal plumbing system. Many water microorganisms result from disruption of biofilm and resuspension of deposits from joints or knees in case of peak flows and pressure jars. To minimize these effects, open the tap at maximum flow for 5 seconds to 10 seconds, then reduce to half flow for the time needed, and place the sample bottle under the tap without closing and re-opening the tap. See Annex A for detailed step-by-step instruction on how to complete a microbiological sample. 7.3 Sampling water as it is delivered to the consumers' tap ix,x In these circumstances we are not concerned with establishing flow from the distribution mains but are concerned about possible contamination within the premises and so it is not necessary to flush the sample tap, except during the normal cleaning routine, as we do not need to flush the internal plumbing system. Obtain permission from the building owner/occupier to enter the premises to take the sample, having explained the procedure (including the cleaning of the taps) to them. To determine the quality as it is delivered to the consumer's tap, ensure that no contamination from the outer surface of the tap reaches the sample. Scrape off any dirt (scale, slime, grease or other extraneous matter) which could fall off, before filling the bottles. Do not sample taps with Page 11 of 40

12 leaking spindles and avoid mixer taps, if possible. Take out any tap nozzle or other attachment or insert (spanners and pliers should be part of the sampling kit). Scrape off any dirty (scale, slime, grease or other extraneous matter) and fully open and close the tap repeatedly to rinse out the dirt from the tap. Disinfect the tap by using a solution of sodium hypochlorite. Never flame a tap inside a consumer's premise. Annex A provides details on how to disinfect taps used for sampling using a sodium hypochlorite solution. Allow the water to flow just long enough to ensure that the sample has no residual disinfectant effect. Place the sample bottle under the tap without closing and re-opening the tap. See Annex A for detailed step-by-step instruction on how to complete a microbiological sample. 7.4 Completing the sample requisition paperwork Once the sample bottles containing the water samples for microbiological examination have been filled, ensure that the appropriate documentation has also been provided to accompany the samples. Along with the sample labels (affixed to the individual sample bottles), the following information will also be required by The Provincial Laboratory for Public Health (ProvLab): Access number (if applicable) Alberta Environment and Sustainable Resource Development Approval Number (if applicable) Alberta Environment and Sustainable Resource Development Reference Number (if applicable) Date and Time of collection, including AM or PM Name and daytime contact phone number (including area code) of sample collector Water supply for: (Name and Address) Feature Code Number (FID number) (if applicable) Study Number (if applicable) Collection site Indicate if samples are required for compliance monitoring with Alberta Environment and Sustainable Resource Development (applies to Alberta Environment and Sustainable Resource Development approved facilities only) Indicate if re-sample is due to previous coliform contamination Name and address of Health Zone where the laboratory report is to be sent Ensure that only ONE sample category is marked and represents the type of water being submitted Indicate source as groundwater (well) or surface water (i.e. lake, river, etc.). See Annex E for detailed information on how to access the services of ProvLab. Page 12 of 40

13 8. Storing samples in a way that preserves the integrity of the sample Immediately after a sample has been collected there is potential for the quality of the water to change. These changes are a result of chemical and/or biological activity in the water. Some parameters such as ph or turbidity can change very quickly and significantly which means they need to be analysed immediately, typically using field test systems or field portable equipment. Other parameters will change more slowly and over a longer period of time but care still needs to be taken to ensure that the quality of the sample arriving for analysis is as close to the quality at the time of sampling as possible and this process is termed 'sample preservation'. Sample preservation usually involves one of two basic steps: refrigeration ph adjustment For example, organic parameters and some inorganic parameters (like nitrate) may be subject to biological deterioration and so refrigeration is used to slow the metabolic activity of microorganisms so that they cannot use these parameters of interest as a food source and so reduce or otherwise change the concentration of the parameter when it is analysed in the laboratory. Other parameters, principally metals, can be adsorbed on to the walls of the sample containers which would mean that any analysis would underestimate the real concentration of the metal of interest. This is combated by preserving the sample through lowering the ph by adding a specified amount of acid either to the container (usually by the laboratory) prior to sampling or in the field by the sampler immediately after the sample has been taken. The laboratory undertaking your analysis will be able to provide you with instructions on how best to preserve samples for individual parameters or suites of parameters. 9. Transportation of the samples to a laboratory for off-site analysis xi It is recommended that all samples be delivered to the laboratory as soon as possible after sampling. Samples should be kept cool (refrigerated) if immediate shipping is not possible. Samples should be packaged to avoid breakage during shipping. Samples must be shipped to arrive at the laboratory before the holding time for the samples has expired (e.g. microbiological samples must reach the laboratory within 24 hours of the sample being taken). The sample container should be sealed for shipping. Doing so will help make obvious any evidence of tampering. This may simply involve the use of a label or similar item that must be torn open to open the box/case. The sample information sheet, if used, must be included in the Page 13 of 40

14 shipping box/case. A written record of how the samples are shipped, the time, date, carrier and tracking numbers for the shipments should be kept by the sampler. 10. Recording results of sampling All results must be recorded and stored in a way that allows them to be easily located again. It is recommended that records are kept on formatted sheets, either paper or computer-based. On these sheets it is helpful to include the target levels so that all readings can be compared to them. These values may help you to identify the need to take corrective action, as appropriate. 11. Additional Resources In addition to the references in Annex F, the following may be found useful for providing additional information on various aspects of sampling: Environmental Public Health Manual for safe Drinking Water Guide for the auditing of water quality sampling BS 8558:20120 Drinking water quality monitoring manual: Physical and chemical parameters. The Microbiology of Drinking Water (2010) Part 2- Practices and procedures for sampling. Water quality Sampling Part 1: Guidance on the design of sampling programmes and sampling techniques. Water quality Sampling Part 21: Guidance on sampling of drinking water distributed by tankers or means other than distribution pipes. Sampling, storage and transportation of water samples. New England States Sample Collection and Preservation Guidance Manual for Drinking Water. Interactive Sampling Guide for Drinking Water System Operators. Alberta Health Services. 3 rd Edition British Standards Institution. May Department of Environment and Conservation. Water Resources Management Division. Newfoundland and Labrador. May Environment Agency. UK odw pdf ISO ISO Private Water Supplies Technical Manual. UK. ate_water/75.html?pmenuid=1&pelementid =28 US EPA Revision 4.2, May 1, States-Sample-Collection-Manual.pdf US EPA. EPA816-F March Page 14 of 40

15 Annex A 2 - Draft Sampling Manual xii Contents 1. General Sampling Procedures 2. Tap Sterilisation - Flaming 3. Tap Sterilisation - Chlorine Solution 4. Preparation of 1% (w/v) Chlorine Solution 5. On-site Determination of Free and Total Chlorine 6. On-site Determination of Chlorine Dioxide 7. Sample Storage and Transportation 8. References Appendix A Sampling Procedure Flow Chart Appendix B Sample Bottle Types and Descriptions Appendix C Sample Kit Appendix D - Field Sheet Records Appendix E Instructions For Use of Chlorine Meter Appendix F Validation of Chlorine Meter Appendix G Instructions For Use of Chlorine Dioxide Meter Appendix H - Validation of Chlorine Dioxide Meter Appendix I Material Safety Data Sheets Note: The relevant paperwork should be inserted into Appendices B, E, F, G, H and I. This information will be specific to the individuals using the manual. 2 Reproduced with grateful permission of the copyright holder Page 15 of 40

16 1. General Sampling Procedures Sample Point 1.1 A sample point should be after any treatment and representative of the water at point of use. 1.2 Remove any attachments (e.g. hoses) or plastic inserts where fitted to the tap which could contaminate the sample. Any issues with the sample point which may affect the sterilisation of the tap or the sample results should be noted on the field sheet. Chemical Sampling 1.3 If a sample is to be taken for first draw metal analysis (lead, copper and nickel) this sample bottle must be filled before the flushing step below (i.e. first issuance). This may be noted on the field sheet and bottle label. Adjust the flow to ensure a gentle and steady stream of water into the bottle. 1.4 The tap must then be flushed for at least 2 minutes to remove any standing water within the pipe work before other chemical samples are taken. (Flush time should be extended for longer service pipes). 1.5 If the private water supply has disinfection in place through chlorination or chlorine dioxide then a residual should be measured (see Section 5 or 6). 1.6 Fill the chemical sample bottles, following closely any instructions in Appendix B or on the labels of the bottles, and observing any expiry dates. Bacteriological Sampling 1.7 If no chemical samples are required, the tap must be flushed for at least 5 minutes (extend flush time for larger service pipes) and, where disinfection by chlorination or chlorine dioxide is in use, then a residual should be measured (see Section 5 or 6). 1.8 The tap will be sterilized by use of a chlorine solution (see Section 2). 1.9 After sterilisation, bacteriological samples should be taken in sterile bottles. Checks should be made that the expiry date is satisfactory and that the sterile seal has not been broken Care should be taken in bacteriological sampling: remove the top and hold with the open end downwards; the top should not be set down on any surface. Page 16 of 40

17 1.11 Place the bottle into a steady stream of water, ensuring it does not touch the tap, and fill to the base of the neck. The bottle should not be rinsed out or be allowed to overflow. A small air gap (2.5 cm) must be left at the top of the bottle If, in taking the sample, it is suspected the sample has been contaminated, the sample and the bottle should be discarded and the procedure restarted. Record Keeping 1.14 Field sheets should be completed with the details listed in Appendix D. If necessary the comments section should describe any changes from routine sampling procedures. If applicable, this should include reasons for samples not being lifted or extreme weather conditions Where pre-labelled bottles are not used, all the information contained on the field sheet should also be recorded on the bottle label and initialled by the sampler. 2. Tap Sterilisation - Flaming 2.1 Sterilisation of sample taps by flaming should only be carried out where it is deemed to be safe to do so and the tap is metal. Generally, in domestic situations, flaming is not recommended. Do not use gloves when handling a blowtorch. 2.2 Clean the outside of the tap, to remove any deposits of grease or dirt, with an alcohol wipe or paper towel moistened with 1% (w/v) chlorine solution. 2.3 Using a gas blowtorch, thoroughly flame around the mouth of the tap using a tight blue flame and work up the spout to the body of the tap until the water held in the spout boils. Care should be taken to ensure that hot water which may spurt out of the tap during flaming does not cause injury. 2.4 After flaming, care should be taken when turning on the tap. Run the water to waste for at least 30 seconds, adjust to a steady flow to avoid splashing and take the sample (refer to Step 1.10). Page 17 of 40

18 3. Tap Sterilisation Chlorine Solution 3.1 Disinfection of taps using chlorine solution (1% (w/v) available chlorine) can be carried out on taps where flaming is not appropriate. This method is suitable for both plastic and metal taps. [Note: A fresh 1% (w/v) chlorine solution should be prepared each day (see Section 4). Where the solution is purchased pre-prepared, ensure the shelf-life of the solution is satisfactory before use.] 3.2 WARNING: The chlorine solution used in this procedure is corrosive and should be handled with care and stored appropriately when transporting. Both gloves and eye protection should be worn when handling this solution. If the solution comes into contact with skin or clothing, the area should be immediately washed with copious amounts of water. 3.3 Clean the outside of the tap, to remove any deposits of grease or dirt, with an alcohol wipe or paper towel moistened with 1% (w/v) chlorine solution. 3.4 Using the wash bottle containing chlorine solution of 1% (w/v) available chlorine spray the outside of the tap and inject the inside of the tap spout. 3.5 Leave the tap for a minimum of 2 minutes to allow the chlorine to disinfect the tap. Then run the tap to waste for a further 2 minutes to ensure all the chlorine has been flushed away before taking the sample (refer to Step 1.10). 3.6 Consult relevant Material Data Safety Sheet (Appendix I) for precautions required in the handling of chlorine solution. 4. Preparation of 1% (w/v) Chlorine Solution 4.1 A chlorine solution, of 1% (w/v) available chlorine, must be prepared each day it is required. [Note: This procedure uses 2.5g Presept tablets and a 250ml wash bottle, if either item differs then refer to the manufacturer s instructions for the preparation of 1% (w/v) chlorine solution.] 4.2 Put on safety glasses and gloves and fill a 250 ml wash bottle to approximately 1/3 full with distilled water; if not available, then tap water may be used. 4.3 Slowly add two Presept tablets (2.5 grams), one at a time, into the wash bottle. Swirl the wash bottle until both tablets have dissolved. This should be carried out in a well ventilated area. As the tablets dissolve, gases will be given off; you should avoid inhaling these gases. Page 18 of 40

19 4.4 Make up to the 250ml mark on the wash bottle with distilled or tap water. Place the lid on the bottle and gently invert the bottle over a sink to mix the solution. Any spillages should be washed away with copious amounts of water. 4.5 The bottle must be labelled Chlorine Solution - 1% (w/v) available chlorine along with the date prepared and an appropriate hazard label. 4.6 To dispose of unused solution, flush down a drain or sink with copious amounts of water. 4.7 Consult relevant Material Data Safety Sheet (Appendix I) for precautions required in the handling of Presept tablets and chlorine solution. 5. On-site Determination of Free and Total Chlorine 5.1 Where treatment of the water at a site is by chlorination, the amount of free and total chlorine in the water should be determined as a measure of the level of disinfection. [Note: If the chlorine residuals measured differ significantly from the range expected at individual sites, the person responsible for the private supply should be informed.] 5.2 Commercial hand-held meters are available for the determination of free and total chlorine levels. 5.3 A copy of the manufacturer s instructions for the chlorine meter being used should be placed in Appendix E and these instructions should be followed in the measurement of free and total chlorine and for the maintenance and calibration of the meter. 5.4 Chlorine meters are calibrated by the manufacturer but check standards are available as a means to validate the calibration. 5.5 The meter should be validated as per manufacturer s instructions (ensure check standards are within expiry dates) and records of the validation kept in Appendix F. 5.6 Consult relevant Material Data Safety Sheet (Appendix I) for precautions required in handling reagents for use with chlorine meters. 6. On-site Determination of Chlorine Dioxide 6.1 Where treatment of the water at a site is by the addition of chlorine dioxide, the amount of chlorine dioxide in the water should be determined as a measure of the level of disinfection. Page 19 of 40

20 [Note: If the chlorine dioxide residuals measured differ significantly from the range expected at individual sites, further investigations will need to be made.] 6.2 Commercial hand-held meters are available for the determination of chlorine dioxide levels. 6.3 The manufacturer s instructions for the chlorine dioxide meter being used should be placed in Appendix G and these instructions should be followed in the measurement of chlorine dioxide and for the maintenance and calibration of the meter. 6.4 All chlorine dioxide meters are calibrated by the manufacturer but check standards are available as a means to validate the calibration. 6.5 The meter should be validated as per manufacturer s instructions (ensure check standards are within expiry dates) and records of the validation kept in Appendix H. 6.6 Consult relevant Material Data Safety Sheet (Appendix I) for precautions required in handling reagents for use with chlorine dioxide meters. 7. Sample Storage and Transportation 7.1 After the samples have been taken the bottles must be stored and transported correctly. 7.2 Bacteriological bottles should be stored upright in a cool box containing appropriate ice packs to retain a temperature, during transportation and storage, of between 2 and 8ºC. [Note: The inside of cool boxes should be cleaned down with a paper towel soaked in 1% (w/v) chlorine solution prior to use. Care should be taken as detailed in step 3.2.] 7.3 Chemical samples should be replaced in any protective wrapping provided with the bottles, and placed in the sample crate. 7.4 The samples should be returned as soon as possible to the laboratory to ensure analysis is undertaken within the timescales required by the laboratory. 7.5 If there is to be any significant delay between sampling and analysis, samples should be stored so as to ensure there is no material change which could significantly affect the sample results. For example, bacteriological samples should be kept in the dark between 2 and 8ºC and analysed within 24 hours. The laboratory should be contacted for advice as appropriate, as samples which have not been stored correctly may not be suitable for analysis. Page 20 of 40

21 Appendix A Sampling Procedure Flow Chart Page 21 of 40

22 Appendix B Sample Bottle Types and Descriptions These will be provided by your laboratory service provider Appendix C Sample Kit Protective gloves Safety glasses Alcohol wipes (70% isopropyl alcohol) 1% (w/v) chlorine solution in labelled 250ml wash bottle for tap sterilisation (Section 3) Gas blowtorch and lighter Digital thermometer capable of reading in 0.1 o C increments Assorted spanners and pliers for dismantling tap fittings Chlorine meter with reagents (if required) Chlorine dioxide meter with reagents (if required) Timer or watch with second hand Field sheets Waterproof pen Sample bottles and crate Cool box and ice packs Paper towels Garbage disposal bags Page 22 of 40

23 Appendix D Example Field Log Sheet Sheet Number Approval Number Name of Waterworks System Date of sampling event Time of sampling Field Measurement Results Total chlorine mg/l Free chlorine mg/l Others: Details of samples taken Bottle ID Bottle Type Bottle Volume Preservation Details Comments Observations Signature of sampler Date Sample received in the laboratory at (time/date) / By From Page 23 of 40

24 Appendix E Instructions For Use of Chlorine Meter This will be supplied by your instrument supplier Appendix F Validation of Chlorine Meter You should follow the manufacturer's requirements for calibration and validation of your meter. Appendix G Instructions For Use of Chlorine Dioxide Meter This will be supplied by your instrument supplier Appendix H - Validation of Chlorine Dioxide Meter You should follow the manufacturer's requirements for calibration and validation of your meter. Appendix I Material Safety Data Sheets These will be supplied by your instrument and chemicals supplier Page 24 of 40

25 Annex B - Best Practice: Operational Monitoring Requirements xiii B.1 Introduction To follow the 'best practice' model of operational sampling, the drinking water system's sampling manual (Section 3 (c) and (d)) should set out the pre-determined operational sampling programme for each year. This programme should set out the frequencies of sampling and how quickly the result is required for each relevant parameter at: each of the raw water sources (intakes to treatment works); each treatment works (or each part of the treatment process); suitable points in each distribution network including each service reservoir/water tower; and at consumer's taps or 'sentinel' taps to allow quality to be monitored at the same point over time. B.2 Operational sampling programme The frequency of sampling for each parameter will depend on how variable its concentration or value is likely to be in the raw water source, during treatment, in the water leaving the treatment works and in the distribution system and its importance or significance in relation to water quality. Drinking water systems may have to carry out additional operational sampling in response to incidents affecting drinking water quality or in emergencies, or may wish to carry out additional microbiological monitoring of the supply to ensure that contamination has not occurred. B.3 Operational sampling points Operational samples may need to be taken from the raw water sources, from individual treatment processes, from the water leaving treatment works, from points in the distribution system such as service reservoirs and water towers and from consumers' taps. B.3.1 The following is a suggested minimum that should be included in the sampling manual regarding sampling points for operational sampling from the raw water source: precise location of the point at which samples of the raw water source are to be taken; the sampling points should be reasonably accessible and if possible uniquely labelled; and a schematic diagram of each raw water source showing the location of the sampling point. Page 25 of 40

26 B.3.2 The following is a suggested minimum that should be included in the sampling manual regarding sampling points for operational sampling from the treatment works: the precise location of the points at which samples are to be taken of the water from the treatment processes and the water leaving the treatment works; sampling points should be reasonably accessible and uniquely labelled; sample point labels should provide information on the sample-line volume and/or recommended time for flushing the line to ensure a representative sample is obtained (see Section 7.2 for an example); a schematic diagram of each treatment works showing the location of each sampling point or points; and guidance on the sampling points. All treatment works sampling points should be fitted with metal sampling taps of a hygienic design that do not have attachments or inserts and that are made from materials that do not affect the concentrations of the parameters being monitored. Water should be supplied to the sampling tap through a sample line of a suitable material that should be as short as possible. The materials should meet NSF Standard 61. B.3.3 The following is a suggested minimum that should be included in the sampling manual regarding sampling points for operational sampling from service reservoirs, water towers and other points in the distribution network: the precise location of the point or points from which a representative sample or samples of the water flowing into the distribution network can be obtained. Where reservoirs/towers are divided into compartments and water does not mix freely between compartments, the sampling points should be located so that samples are representative of all the water leaving the service reservoir/water tower or, alternatively, each compartment or its outlet should have a separate sampling point. Similar sampling arrangements should apply where there are two or more service reservoirs on a site; sampling points should be reasonably accessible and uniquely labelled; sample point labels should provide information on the sample-line volume and/or recommended time for flushing the line to ensure a representative sample is obtained (see Section 7.2 for an example); a schematic diagram of each service reservoir/tower or service reservoir/tower complex showing the location of the sampling point or points; all service reservoirs/tower outlets should be fitted with metal sampling taps of a hygienic design that do not have attachments or inserts and that are made from materials that do not affect the concentrations of the parameters being monitored. Water should be supplied to the sampling tap through a sample line of a suitable material that should be as short as possible. The materials should meet NSF Standard 61. Where it is impracticable to provide a tap on the reservoir site, a tap should be provided on the outlet main at the Page 26 of 40

27 nearest point to the reservoir. Dip sampling should not be used. Break pressure tanks that do not provide a strategic reserve of water are not considered as service reservoirs/water towers; and other operational sampling points in the distribution system could be selected consumers' taps, or 'sentinel' taps (such as taps in public buildings). B.4 Treatment works Each drinking water system should, as best practice, have a treatment works operational sampling programme to check the overall effectiveness of the treatment processes and to check the operation of individual processes, in particular the effectiveness of disinfection and the minimisation of disinfection by-products. Sampling points for operational samples should be representative of water quality for the process to be monitored. Each drinking water system should specify the parameters and the frequency of sampling for each important process. Some parameters must be monitored continuously (e.g. turbidity or chlorine) and other parameters may be monitored continuously on-line (e.g. ph) depending on the terms set out in the system's approval conditions or Code of Practice. Other parameters will be monitored at appropriate intervals. The parameters will depend on raw water quality and the treatment processes used and should include monitoring for those parameters that the treatment processes are designed to remove (such as microbiological, pesticides, nitrate, etc.). Drinking water systems should also specify how quickly the samples should be analysed and the results sent to the operator of the treatment works. The following paragraphs give some examples for the common treatment processes. B.4.1. For works using coagulation the operational monitoring could include: jar tests to determine optimum coagulant dose and coagulation ph (for automatic coagulation controller); coagulant dose; coagulation ph; residual coagulant following clarification/settlement (e.g. aluminium or iron). B.4.2 For works using conventional filtration the operational monitoring could include: on-line continuous turbidity monitoring of the filtrate from each filter; on-line continuous turbidity monitoring of the combined filtrate from all filters; and ph value as it may be need adjusting for efficient disinfection. B.4.3 For works using granular activated carbon (GAC) either as a separate filtration process or incorporated into slow sand filters, the operational monitoring will depend on the purpose of the GAC (colour removal, general organics removal or specific organics removal such as individual pesticides) and could include: Page 27 of 40

28 total organic carbon (TOC); colour; turbidity; and specific organic compounds such as individual pesticides. B.4.4 For works using chlorination as the disinfectant: chlorine dose; ph value; and on-line continuous monitoring of chlorine residual in the final water. B.4.5 For the final water, before entering the distribution network, for a works using the above processes the operational monitoring could include: E. coli and total coliforms; colony counts at 22 o C; on-line continuous monitoring for chlorine residual; on-line continuous monitoring for turbidity; conductivity; ph value; colour; aluminium or iron residual; fluoride (when the supply is fluoridated); trihalomethanes; and any other parameter the works is specifically designed to remove. B.5 Distribution network Each drinking water system should, as best practice, have a distribution network operational sampling programme to check whether there has been any contamination or deterioration of quality within the network. Often this programme will consist of sampling from service reservoirs and water towers but may also include other points within the network. Each drinking water system should specify the parameters and the frequency of sampling. Drinking water systems should also specify how quickly the samples should be analysed and the results sent to the network operator. The following paragraphs give some examples for distribution networks. B.5.1 For service reservoirs and water towers the operational monitoring could include: E. coli and total coliforms colony counts at 22 o C; chlorine residual. Page 28 of 40

29 B.5.2 For the distribution network the operational monitoring could include, at appropriate points throughout the network that are representative of the whole network: chlorine residual; and ph value/conductivity. Page 29 of 40

30 Annex C - Example Field Log Sheet Sheet Number Approval Number Name of Waterworks System Date of sampling event Time of sampling Field Measurement Results Total chlorine mg/l Free chlorine mg/l Others: Details of Samples Taken Bottle ID Bottle Type Bottle Volume Preservation Details Comments Observations Signature of sampler Date Sample received in the laboratory at (time/date) / By From Page 30 of 40

31 Annex D - Sampling Taps If a sampling tap is to be installed or used specifically for sample collection the then following requirements (taken from ISO :2006 section 5.5.2) should be followed: a) the sampling line should be as short as possible, in good condition and capable of being flushed at full flow rate; b) the sampling line should not protrude inside the pipe wall of the water main; c) the sampling line should preferably connect to the main piping immediately downstream from a valve, elbow or fitting that causes turbulent flow; d) water from a mains spur should not be considered representative of water in the main; e) the sampling line should be of materials suitable for the conveyance of drinking water [meet the requirements of NSF 61]; f) the sampling line should not include T-junctions, which might result in stagnation; g) the sampling time and sample tap should be adequately protected against frost; h) the sample tap location should be protected from vandalism and contamination; i) if the sample tap is to be flame-disinfected, it is important that there are no flammable materials or fumes nearby; j) there should be adequate space to fill a variety of bottle sizes; k) there should be an adequate supply of water to the sample tap at all times; l) the site should have adequate drainage, i.e. water discharged by flushing should be able to run off freely; m) for each fixed location, the operator (sampler) should have a location plan, details of access, and any special flushing or collection instructions. It is recommended that a sample point chosen for frequent sampling (e.g. monitoring the working of a process in a treatment plant or sampling water entering distribution) should have a sample tap suitable for easy sampling for microbiological, physical and chemical analysis. An example is given in Figure D-1. Irrespective of absolute dimensions of the device illustrated in Figure D-1, it is important that the neck of the receiving vessel allows adequate passage of the water into the container. In addition, there should be sufficient space between the head of the waste funnel and the sample tap outlet to allow unhindered manipulation of each sample container. Page 31 of 40

32 Figure D-1 - Example of a sample tap suitable for frequent sampling Page 32 of 40

33 Annex E - The Provincial Laboratory for Public Health (ProvLab) CALGARY SITE SPECIFIC INFORMATION HOURS OF OPERATION 0700 to 2300 hours Monday to Friday 0700 to 1800 hours Saturday 0700 to 1700 hours Sunday and statutory holidays NOTE: Emergency service is available 24 hours daily. Please contact the Microbiologist/Virologist on call at (ask for MOC or VOC) to access this testing. SAMPLE DELIVERIES ProvLab 3030 Hospital Drive NW Calgary, Alberta T2N 4W4 Telephone The entrance is located on the West side of Foothills Hospital, Special Services Building. For Water Samples Only: HOURS OF OPERATION for Environmental Waters Laboratory: 0800 to 1630 hours 7 days a week and statutory holidays Samples submitted for routine testing, received in the laboratory after 1600 hours, are processed the next day; exceptions may apply for special investigative or follow-up sampling. If water samples must be processed after regular hours, on weekends or statutory holidays, contact the Environmental Waters Laboratory ( , press 5 ), during regular working hours to make special arrangements. Page 33 of 40

34 MAP: PROVLAB CALGARY SITE Provincial Laboratory for Public Health Calgary Site Page 34 of 40

35 EDMONTON SITE SPECIFIC INFORMATION HOURS OF OPERATION 24 Hour service available on a daily basis NOTE: For clinical consultation please contact the Microbiologist/Virologist On Call at (UAH Switchboard) or (Laboratory). SAMPLE DELIVERIES ProvLab and Medical Microbiology Laboratory, UAH Walter Mackenzie Health Sciences Centre University of Alberta Hospitals Street Edmonton, Alberta T6G 2J2 Telephone: Use the Provincial Laboratory Entrance, South end of Walter Mackenzie Health Sciences Centre (83 Avenue). For Water Samples Only: HOURS OF OPERATION for Environmental Microbiology Laboratory: 0700 to 1630 hours Monday to Friday 0745 to 1600 hours Saturday, Sunday and statutory holidays Samples submitted for routine testing received in the laboratory after 1600 hours are processed the next day; exceptions may apply for special investigative or follow-up sampling. If water samples must be processed after regular hours, on weekends or statutory holidays, contact the Environmental Microbiology Laboratory ( , press 4 ) during regular working hours to make special arrangements. Page 35 of 40

36 MAP: PROVLAB AND MEDICAL MICROBIOLOGY LABORATORY EDMONTON SITE Provincial Laboratory for Public Health Edmonton Site Page 36 of 40