Risk-based approaches towards strengthening drinking water quality surveillance

Acknowledgements

Executive summary (short summary of the core principles and key messages for policy makers)

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ContentsForeword................................................................................................................................................3

Introduction...........................................................................................................................................4

Key message 1 – “Surveillance is a core public health function”............................................................7

Key message 2 – “Surveillance is a governmental responsibility”........................................................10

Key message 3 - “Know your system to know your threats”................................................................13

Key message 4 – “Protect rather than detect”.....................................................................................17

Key message 5 – “Don’t monitor what is not there”............................................................................23

Key message 6 – “Water quality monitoring is too little, too late”.......................................................25

Key message 7 – “Surveillance improve the preparedness of water supplies”....................................29

Key message 8 – “Trustful communication of risks is important to ensure water safety”....................33

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Foreword

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Introduction

Surveillance in the Protocol on water and healthThe Protocol on Water and Health to the 1992 Convention on the Protection and Use of Transboundary Water Courses and International Lakes, has the objective (Article 1):

‘…to protect human health and well-being, both individual and collective, within a framework of sustainable development, through improving water management, including the protection of water ecosystems, and by preventing, controlling and reducing water-related diseases’. (WHO/UNECE, 2000)

The Protocol is the first international agreement of its kind adopted specifically to attain an adequate supply of safe drinking water and adequate sanitation for everyone, and effectively protect water used as a source of drinking water.1 This requirement applies to both small and large water supplies, recognising that there is a difference, usually due to available resources.

The Protocol on Water and Health makes several references to drinking-water quality surveillance:

In accordance with Article 6 Paragraph 2 (a), the Parties shall establish targets for the standards and levels of performance that need to be achieved or maintained for a high level of protection against water-related disease, including on the quality of drinking-water supplied, taking into account the Guidelines for Drinking-water Quality (GDWQ) of the World Health Organization (WHO);

In accordance with Article 6 Paragraph 5 (c), Parties shall establish and maintain a legal and institutional framework for monitoring and enforcing standards for the quality of drinking-water;

In accordance with Article 14 (h) Parties shall promote the operation of effective networks to monitor and assess the provision and quality of water-related services, and development of integrated information systems.

Supporting countries in building effective systems for surveillance of drinking-water quality is a priority area of work under the Protocol. A regional meeting on effective approaches to drinking-water quality surveillance, held in Oslo in May 2015, recognized the importance and need for applying risk-based approaches in standard-setting and surveillance for both large and small-scale water supplies. It recommended the development of an advocacy document for decision makers to support uptake of risk-based approaches in regulations and practice2.

The WHO framework for safe drinking waterThe WHO framework for safe drinking-water recommended by the WHO Guidelines for Drinking Water Quality (GDWQ) consists of three components: health-based targets, set by the national

1 http://www.unece.org/fileadmin/DAM/env/documents/2000/wat/mp.wat.2000.1.e.pdf 2ttp://www.unece.org/?id=297523 For more details see http://www.euro.who.int/en/health-topics/environment-and-health/water-and-sanitation/publications/water-and-sanitation-in-the-who-european-region-2014-highlights/effective-approaches-to-drinking-water-quality-surveillance

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regulatory body; a risk-based preventive management approach to ensure safety of drinking-water (WHO, 2011) (e.g. Water Safety Plans, drawn up by the water supplier); and independent surveillance, carried out by a surveillance agency such as the ministry of health (WHO, 2015).

Drinking-water quality surveillance is defined in Chapter 5 of the GDWQ as: …the continuous and vigilant public health assessment and review of the safety and acceptability of drinking-water supplies (WHO, 2011). It is one of the core components of the framework, and is an essential public health function. However, to be effective, drinking-water quality surveillance needs to be aligned with risk-based principles; including prioritization of monitoring parameters and surveillance efforts based on Water Safety Plan (WSP) outcomes. Risk-based surveillance of drinking-water quality aims to provide an understanding of hazards, hazardous events and efficacy of control measures throughout the water supply system, from catchment/source through treatment and distribution to the consumer, based on the outcomes of using a risk assessment tool such as sanitary inspections or Water Safety Plans and drinking-water quality monitoring. This is recognised by the EU and by signatories to the Protocol on Water and Health to the Convention on the Protection and Use of Transboundary Watercourses and International Lakes.

The difference between water quality monitoring and surveillanceIt is important to understand that water quality monitoring is one small part of drinking-water surveillance, although it is an important part when used in the framework for safe drinking water. A risk-based approach to surveillance comprises of several choices and decisions made throughout the whole water supply system, including the management of the system. Surveillance includes the sources and activities in the catchment, abstraction, treatment, storage, distribution system and the consumer. Surveillance of drinking-water involves a systematic programme of data collection and surveys that may include water sampling and analysis, and sanitary inspection of the supply system. Hence, water quality monitoring and sanitary inspections are integral components of surveillance, not independent activities. Considering that water supply is a dynamic system under constant change, the risks in the water supply system also need to be continuously assessed. This requires the use of holistic approaches with a high degree of flexibility in order to foresee, and preferably prevent, the emerging and current risks to the supply.

The benefits of risk-based surveillanceIn order to protect human health, it is vital to have an overview of the potential hazards people may be exposed to through their drinking-water, and an understanding of how these hazards may be prevented. These are the core functions of a risk-based approach to surveillance. Thus, by concentrating on the protection of public health, drinking water surveillance contributes to the fulfilment of Sustainable Development Goals 3 and 6. Risk-based drinking water surveillance is effective both in terms of protecting public health, and in terms use of resources.

Drinking-water surveillance involves more than just water quality monitoring, it is “ …the external and periodic review of all aspects of water quality and public health safety”, (Rickert et al. 2016) in which water quality monitoring, risk and trend analysis are important components. The objectives of

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drinking water quality surveillance are to gain an understanding of hazards, hazardous events and efficacy of control measures throughout the water supply system. Risk-based approaches in drinking water surveillance is about using the available resources where it gives the best public health protection. In order to manage the potential risks, it is furthermore essential to understand how these hazards could be foreseen and prevented. Surveillance can be seen as a mindset and this document attempts to bring reflection and good examples in this regard.

Chemistry and microbiology laboratories are a vital resource of any water supply company, and of the public health agencies engaged in the monitoring of supplies. However, the costs of building, equipping, maintaining and resourcing laboratories are very high, and these costs rise even further when human resources, finance systems, quality control systems, and information systems are included. Some test methods are relatively simple to perform and relatively cheap to do, but there are many other tests that require sophisticated and expensive equipment as well as highly trained personnel. Hence, cost is a significant barrier to the introduction of new laboratories at any level, but particularly if they are to serve communities that rely on small water supplies. Where laboratories are available to take samples from small water supplies, it is not uncommon for them to serve multiple industries, in particular the lucrative food industry, and may not have a specialist knowledge of water chemistry or microbiology.

Recognised deficiencies in the value of monitoring, the limited availability of specialist laboratories, and the cost of monitoring can be partially overcome by introducing risk-based drinking-water quality surveillance. The tools that are available, which include sanitary surveys, provide vital information to inform decisions about the most significant risks to the supply and the measures that can be taken to manage the risks. Targeted monitoring, if considered necessary, can be used to confirm the risks and verify the efficacy of any interventions. Not only is this approach a more cost-effective use of resources, it is a potent stimulant for good management as an alternative to reliance on end-point testing.

Water safety plans and surveillance The World Health Organization (WHO) Guidelines for drinking-water quality (WHO, 2011) recommends water safety planning as the basis for the provision of safe and clean drinking-water in both urban and rural areas. Drinking water quality surveillance and Water Safety Plans have some overlapping intentions, and outcomes, which play an essential role in risk-based approach to surveillance.

The WHO/International Water Association (IWA) Water Safety Plan manual notes:

“There can be a tendency for the identification of hazards to be limited to thinking about those direct inputs to the water supply system impacting microbial and chemical parameters, as these are important in terms of compliance with water quality standards. However, the approach to ensure safe water must go much wider, with consideration of aspects such as potential for flood damage, sufficiency of source water and alternative supplies, availability and reliability of power supplies, the quality of treatment chemicals and materials, training programmes, the availability of trained staff,

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service reservoir cleaning, knowledge of the distribution system, security, emergency procedures, reliability of communication systems and availability of laboratory facilities all requiring risk assessment (WHO/IWA, 2009).”

Significant health gains are achieved by making the transition from the perspective of water supply as a basic piped water supply to the perspective of being a system that is systematically managed. As for risk-based surveillance, a Water Safety Plan is also a “way of thinking” and entails an iterative approach to identifying, assessing and managing the risks to a water supply system throughout all steps from catchment to tap.

A short reading guide for this documentThis document has been designed around a set of key messages that underlie the principles of risk-based approaches in drinking-water quality surveillance. The key messages of the document were formulated based on discussions with the Expert Group on Risk-Based Surveillance of Drinking-Water Quality, under the Protocol on Water and Health, and the WHO technical programme.

The purpose of each key message is explained to provide the context, and then its role in risk-based drinking-water quality surveillance is explained and reflected upon, illustrated by a case study. Using a clear and concise format the document aims to support decision makers, regulators and national and sub-national public health officials, to better understand and appreciate the added value of risk-based water-quality surveillance (including monitoring and identification of what to monitor) and thereby strengthen surveillance systems for better protection of public health. The document will provide a strong rationale for the application of risk-based approaches, to strengthen drinking-water quality surveillance and the prioritization of surveillance efforts considering local hazards and available resources.

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Key message 1 – “Surveillance is a core public health function”Risk-based drinking-water quality surveillance is a fundamental activity for the continuing protection of public health through the delivery of safe drinking-water. It utilizes the principles of Water Safety Plans (WSP) and risk management expressed in the framework for safe drinking-water.

BackgroundDrinking-water can be a vehicle for the transmission of disease, so the provision of safe drinking-water has a vital public health function. By providing drinking-water every supplier assumes the responsibility to protect public health. It is incumbent upon the supplier to apply current good practice to produce and supply drinking water that is as safe as can be achieved in particular circumstances. Risk-based drinking-water quality surveillance is accepted best practice within the framework of safe drinking-water directing the most efficient use of resources to ensure the protection of public health.

Water quality monitoring is an essential part of the verification of the water quality, and long-term follow up of a water supply system. However, this requires that the parameters and frequency of the sampling reflect the characteristics water supply system. For most of the 20 th Century the quality of drinking-water supply systems was assessed by testing water samples for compliance against a list of parameters for which standards had been set. Sampling frequencies, methodology, parameter values and compliance rates were tightly defined in regulations governing water supplies. Provided that the concentrations of parameters were within the specified limits the water was judged to be safe. Therefore, a rigid adherence to compliance monitoring as the sole measure of safety has substantial limitations.

Protection of public health from outbreaks of waterborne microbial diseases has been the motivation behind changes to the management and operation of drinking-water delivery systems (Stein 2000; Hrudey et al. 2003). Importantly, some waterborne outbreaks were shown to occur when water quality test results show compliance with standards (Barrell et al., 2000), demonstrating that infrequent testing of parameters is not always informative and may miss critical contamination events and information on potential contamination risks in supply systems. With few exceptions, the investigations set up in response to the most significant outbreaks identified operational failures that were compounded by an inadequate response to test results indicating the presence of contamination (for example: Stein 2000). Whether or not a Water Safety Plan was named specifically in the recommendations of these investigations, all were clear about the need for building an understanding of the risks from catchment through to the consumer, and about managing the risks, including operational monitoring to ensure that management options are optimised at all times: the core principles of a Water Safety Plan.

The third edition of the WHO Guidelines for Drinking-water Quality (2004) introduced a risk assessment and risk management approach that involves the management of drinking-water supplies using a comprehensive analysis of hazards that might adversely affect a water supply, and an

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assessment of the risks that the hazards will have an adverse impact. This concept, Water Safety Planns, forms the core of effective water quality management practices with the requirement to put in place barriers to mitigate the identified risks and to monitor the operation of the barriers (operational monitoring) on a continuous basis to ensure that they are working properly. The barriers can include management procedures as well as technology and operational monitoring includes parameters that are easy to measure and can be more or less sophisticated according to the resources available. Water quality monitoring has not been removed from the Guidelines, but the emphasis has been changed: it is now used to verify the successful operation of the Water Safety Plan rather than being the sole indicator of safety.

This value of risk-based surveillance has been recognised by the EU and has been adopted in the EU Drinking Water Directive (Council Directive 98/83/EC of 3 November 1998 on the quality of water intended for human consumption) (which allows member states to “[…] provide for the possibility to derogate from the parameters and sampling frequencies [laid down], provided that a risk assessment is carried out…” (EU, 1998; EU 2015)). It is contained in International Standard BS EN 15975-2. In that respect, one may say that a risk-based approach to managing safe water supplies has become an accepted best practice and risk-based water quality surveillance is a vital component of this approach. Indeed, the EU Drinking Water Directive obliges Member States to manage their water using a risk-based approach. The approach recognises the value of using existing monitoring data to show whether a parameter is consistently below the parametric value to demonstrate that compliance monitoring at the frequency specified would not be a good use of resources. It should be noted that no derogation is allowed for microbiological parameters. The approach is a valuable tool to verify the risk assessment/management approach and alerts the responsible authorities to the possibility of water becoming unsafe.

Implementation of a Water Safety Plan (or other risk assessment/risk management approaches) can bring substantial benefits in terms of increased compliance with national standards and reduced microbial and chemical contamination of drinking-water (Setty et al. 2018). Furthermore, a direct benefit to public health through a reduction in the incidence of diarrhoeal disease is reported (Gunnarsdottir et al. 2012; Jetoo et al. 2015). Risk-based water quality surveillance helps to protect the health of consumers in the most cost-effective way by identifying whether the hazards and risks are under proper and continuing control. However, risk-based water quality surveillance is not an independent activity; it takes place within the framework of an operational Water Safety Plan.

Case Example

Title: Incorporation of the risk-based surveillance into legislation - example of the European Drinking Water DirectiveCase study number: CS2

Location: European Union

Relevant principle:Risk-based water quality surveillance incorporates the principles of surveillance and risk management expressed in the WHO Guidelines for Drinking-Water Quality (4th Edition), the EU Commission Directive 2015/1787, and International Standard BS EN 15975-2.

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Background to the case study: The EU Commission Directive 2015/1787 amended the Annexes II and III of the EU Drinking Water Directive 98/83/EC. Annex II lays down the requirement of drinking water quality monitoring, including parameters to be monitored, monitoring frequency, and the point of sampling. The amendment replaced the previous rigid monitoring scheme by a more flexible, risk-based monitoring programme.Elements of monitoring programmes Monitoring frequency of various parameters

Description of case study:The amendment requires the EU member states to develop monitoring programmes to ensure that the delivered water is safe and meets the quality requirements laid down in Annex I of DWD. The monitoring programmes do not rely solely on end product testing, but may also include elements of operational monitoring and sanitary inspections (Fig. 1). The minimum frequency of water testing is set based on the volume of supplied water. Basic bacterial indicators, organoleptic properties and a limited number of other parameters (depending on the applied water treatment or the outcome of the risk assessment) are monitored with high frequency, while the “long list parameters” only with a lower frequency (Fig. 2). Sample numbers may be reduced further (even to zero) for those parameters which were not detected in previous measurements, or only present in low concentration, and the risk assessment indicates that the breach of compliance is unlikely. Though the point of compliance is the consumers’ tap, samples may be taken at other points in the water supply system if it is demonstrated to be equivalent. Lessons learned: The incorporation of important elements of risk-based approach into the EU drinking water directive can accelerate the uptake of risk-based supply operation as well as risk-based surveillance in the member states. Recommendations: Transition from end-product testing to risk-based surveillance should be gradual. Basic water quality testing should be maintained (simple, cost-effective measurements of high indicative value), while the frequency and scope of more sophisticated analysis should be

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Analysis of discrete water

samples

Online measurements

Functionality and

maintenance records

Inspection of catchment area and

infrastructure

Stable

parameters

<LLQStable parameters, <60 % of the limit

value

All other chemical and microbiological parameters listed in Annex I

E. coli, coliform bacteria, colony count 22°C, colour, turbidity , taste, odour, pH, conductivity + others

indicated by risk assessment

determined by risk assessment. ReferencesEU Commission Directive 2015/1787 amending the 98/83/EC directive

Bibliography and further readingEU (1998). Council Directive 98/83/EC of 3 November 1998 on the quality of water intended for human consumption. Official Journal L 330 , 05/12/1998 P. 0032 – 0054.

EU (2015). Commission Directive (EU) 2015/1787 of 6 October 2015 amending Annexes II and III to Council Directive 98/83/EC on the quality of water intended for human consumption.

Gunnarsdottir, M.J. et al., 2012. Benefits of Water Safety Plans: Microbiology, Compliance, and Public Health. Environmental Science and Technology, 46, pp.7782–7789.

Hrudey, S.E. et al., 2003. A fatal waterborne disease epidemic in Walkerton, Ontario: comparison with other waterborne outbreaks in the developed world. Water science and technology, 47(3), pp.7–14. Available at: http://www.ncbi.nlm.nih.gov/pubmed/12638998.

Jetoo, S., Grover, V.I. & Krantzberg, G., 2015. The toledo drinking water advisory: Suggested application of the water safety planning approach. Sustainability, 7(8), pp.9787–9808.

Rickert, E.B., Barrenberg, E. & Schmoll, O., 2016. TAKING POLICY ACTION TO IMPROVE SMALL-SCALE WATER SUPPLY AND SANITATION SYSTEMS: Tools and good practices from the pan-European region, Copenhagen.

Setty K.E. et al., 2018. Time series study of weather, water quality, and acute gastroenteritis at Water Safety Plan implementation sites in France and Spain, International Journal of Hygiene and Environmental Health 221 (2018) 714–726.

Stein, P.L., 2000. The great Sydney water crisis of 1998. Water, Air, and Soil Pollution, 123(1–4), pp.419–436. Available at: https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034302698&partnerID=40&md5=51d197255132dfeec16d04c7e2da7b50.

WHO (2015). Effective approaches to drinkingwater quality surveillance Meeting report, 6-7 May 2015, Oslo, Norway. World Health Organization.

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Key message 2 – “Surveillance is a governmental responsibility”Risk-based surveillance is critical to the protection of public health. It is a responsibility of the government to establish legal and regulatory requirements for implementation of risk-based drinking-water quality surveillance.

BackgroundDiseases related to contamination of drinking water constitute a major burden on human health (WHO, 2011). This is often demonstrated by outbreaks of disease caused by pathogens. A recent report by the WHO Regional Office for Europe and the United Nations Economic Commission for Europe (WHO, 2016), showed that approximately 18% of investigated outbreaks of gastrointestinal disease may be associated with water. Between 2010 and 2012 there was a total of 279 outbreaks reported under the Protocol on Water and Health, with over 70% of these outbreaks being caused by Hepatitis A virus. Between 2000 and 2014, 68 recorded outbreaks of waterborne disease occurred as a result of contaminated drinking-water supplies (Moreira & Bondelind 2017). Whilst the majority of waterborne diseases is due to microbial pathogens, there is a significant burden of disease that is due to high concentrations of waterborne arsenic and fluoride. Moreira & Bondelind (2017) have categorised the outbreaks according to the reported cause. Failures in integrity of the distribution system, in the form of cross-connections, pipe breaks and ingress of wastewater, was the most common cause of disease outbreaks, but the largest number of cases (over 60,000) was attributed to surface water contamination (Moreira & Bondelind 2017). A review of outbreaks and reported causes in private water supplies over a 40-year period has been compiled by the Drinking Water Inspectorate of England and Wales (DWI, 2014). Although the number of outbreaks was low it was noticeable that the number in public water systems was less than those in private supplies in spite of the vastly greater proportion of population being supplied from pubic supplies. Improvements in the quality of drinking water provide significant health benefits; hence, managing water supplies to protect the safety of drinking water is a vital public health function (WHO, 2011).

Water suppliers are at the forefront of protecting the health of consumers by ensuring that their water supplies are safe. The potential for harm, if safe water supplies fail, could be immense and the responsible for water supply systems need to be equipped with rules and regulations that ensure the safety of the water. Legislation and regulation are inextricably linked with management by establishing the requirements for effective surveillance. Risk assessments can be considered as a regulatory tool in as much as they deal with all types of hazards, including those that are covered by standards and monitoring, and those that are not. An example of the latter would be an irregular power supply that represents a risk to drinking-water quality, but is not controlled by testing. However, a risk assessment would identify the hazard and give the water supplier an opportunity to mitigate it. This would then serve as due diligence if an incident occurred. Ultimately, it is the responsibility of the water supplier to fulfil this function (WHO, 2011), but the supplier requires an appropriate regulatory framework within which to operate and the resources to carry out the work.

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A number of countries’ regulations for drinking-water quality now specify a requirement for water suppliers to implement a risk assessment and risk management approach (e.g. a Water Safety Plan) to the production and distribution of drinking water (Charles and Pond, 2015). The level of detail required varies, but for regulations requiring implementation of risk assessments/management to be effective it is essential that water suppliers fully understand the approach. This should be flexible to ensure that it is successfully adapted to individual supplies and it is important that regulations do not become so prescriptive as to prevent water suppliers from developing approaches that work well for them.

The risk assessment and management approach allows the regulator to gain insight into how well the supplier understands and protects the system by looking at the hazard assessment and control measures. Where there is a regulatory requirement, the regulator can become the external auditor.

Case Example Title: New risk-based Norwegian Drinking Water Regulation

Reference: HYPERLINK "https://lovdata.no/dokument/SF/forskrift/2016-12-22-1868?q=drikkevannsforskriften"https://lovdata.no/dokument/SF/forskrift/2016-12-22-1868?q=drikkevannsforskriften

https://www.mattilsynet.no/mat_og_vann/vann/vannforsyningssystem/de_viktigste_endringene_i_den_nye_drikkevannsforskriften.25148Sorry, these are both only in Norwegian.

Location: Norway

Relevant principle:Principle 1: Risk-based drinking-water quality surveillance is a fundamental activity for the protection of public health through the delivery of safe drinking-water.

Background to the case study: The previous Norwegian Drinking Water Regulation from December 2001 based on Council Directive 98/83/EC, did not have a risk-based approach. The annexes from the Directive was copied into the Regulation as a minimum set of parameters to be tested at minimum frequencies.

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Description of case study:A new Norwegian Drinking Water Regulation was approved December 2016 and brought into force 1st January 2017. The Regulation is based on Council Directive 98/83/EC latest amended by Commission Directive (EU) 2015/1787 and has a distinct risk-based approach.

Water supply undertakings are imposed to map potential hazards from catchment to consumer and systematically manage the risks. This is a main article (Article 6) of the regulation and many of the following articles are based on this article. E.g. according to article 19 the water supply undertaking has to draw up a plan for water sampling and analysis based on the mapping of potential hazards. Still there are minimum requirements according to the Directive, but the main effort is to ensure that potential risks are managed and monitored.

In addition several other paragraphs are based on the main principle of risk-based approach (Art. 6). E.g. Art. 12 requiring safeguards measures to protect the catchment area and Art. 13 requiring proper methods for water treatment.

The water supply undertakings are themselves responsible for monitoring the quality of the water and to notify the Norwegian Food Safety Authority (NFSA) if there are any irregularities. NFSA get yearly reports from the water supply undertakings and perform risk-based inspections and audits.

Lessons learned:The water supply undertakings are imposed to carry out a risk-based approach when dealing with safeguard measures, water treatment, water distribution and monitoring. The approach has been well received by the water works.

Recommendations:Make simple and distinct regulatory requirements in national law to ensure a risk-based approach.

Author:Stig Atle VangeSenior AdvisorNorwegian Ministry of Health and Care Services

Date: 03/07/2018

Bibliography and further readingAndersson, T. et al., 2014. Syndromic surveillance for local outbreak detection and awareness:

evaluating outbreak signals of acute gastroenteritis in telephone triage, web-based queries and over-the-counter pharmacy sales. Epidemiology and Infection, 142(2), pp.303–313. Available at: http://www.journals.cambridge.org/abstract_S0950268813001088.

Charles, K and Pond, K. (2015) Drinking water quality regulations. In: Bartram, J., Coclanis, PA., Gute, DM., Kay, D., McFadyen, S., Pond, K., Robertson, W. and Rouse, MJ (eds). Routledge Handbook of Water and Health. London and New Yorkl: Routledge.

DWI (2014). (http://www.dwi.gov.uk/research/completed-research/reports/DWI70-2-258.pdf)

EU (1998). Council Directive 98/83/EC of 3 November 1998 on the quality of water intended for human consumption. Official Journal L 330 , 05/12/1998 P. 0032 – 0054.

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EU (2015). Commission Directive (EU) 2015/1787 of 6 October 2015 amending Annexes II and III to Council Directive 98/83/EC on the quality of water intended for human consumption.EU (1998)

Hrudey, S.E. et al., 2003. A fatal waterborne disease epidemic in Walkerton, Ontario: comparison with other waterborne outbreaks in the developed world. Water science and technology, 47(3), pp.7–14. Available at: http://www.ncbi.nlm.nih.gov/pubmed/12638998.

Moreira, N.A. & Bondelind, M., 2017. Safe drinking water and waterborne outbreaks. Journal of Water and Health, 15(1), pp.83–96. Available at: http://jwh.iwaponline.com/lookup/doi/10.2166/wh.2016.103.

WHO 2011. Guidelines for drinking-water quality - 4th ed. World Health Organisation, Geneva.

WHO 2016. The situation of water-related infectious diseases in the pan-European region. Eds Alexandra V Kulinkina, Enkhtsetseg Shinee, Bernardo Rafael Guzmán Herrador, Karin Nygård and Oliver Schmoll. WHO Regional Office for Europe, Copenhagen. ISBN 9 789289 052023

Widerström, M. et al., 2014. Large outbreak of Cryptosporidium hominis infection transmitted through the public water supply, Sweden. Emerging Infectious Diseases, 20(4), pp.581–589.

Key message 3 - “Know your system”Risk-based drinking-water quality surveillance builds in-depth knowledge of the water system from catchment to consumer, identifying and monitoring the hazards that pose the greatest risks to the population and assessing how well risk mitigation measures work and continue to work.

BackgroundRisk-based water quality surveillance sits at the interface between the physical elements of the water supply system and the water quality monitoring and management activities. The identification of hazards and assessment of the risks in the system will provide a rationale for prioritizing strategies and improvement actions to control the hazards. This is represented in Figure 1 where the role of risk-based surveillance is symbolised by the red, dashed, vertical line, with the elements of the water system to the left and the monitoring activities to the right. The figure lacks feedback pathways, but the unidirectional flow is sufficient to explain this principle.

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Figure 1 The interface between water supply, risk-based surveillance, and monitoring to achieve safe drinking-water.

Risk-based surveillance drives the purpose of water quality monitoring and control measures to mitigate contamination risks, as shown in the column on the right of the surveillance activity in Figure 1 but is itself determined by the nature and condition of the water supply system. For example, the type of water source – groundwater or surface water – and the catchment that feeds it will determine the quality of the water. While the potential number of influencing factors in the catchment can be very large, an appropriate assessment of the catchment will identify the most important risks. Source water quality monitoring and the use of risk assessment tools such as sanitary inspections (see key message 4) can then be concentrated on verifying the levels of contaminants and the likely sources of pollution. This information, in turn, is an important driver to

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aid incremental improvement of supply quality where this is appropriate. Risk-based surveillance will help in identifying the most pressing needs for improvement which will be moderated by available resources and it will also help to identify improvements that give the greatest overall benefits for least cost.

The same reasoning can be applied to all other components of the water supply system. Thus, by implementing risk-based surveillance at each component of the water supply system, the operator will build an in-depth knowledge of the system. It is important to acknowledge that building such in-depth knowledge is not a “one-time” activity; it requires continuous engagement and developing awareness directed towards the water supply systems and factors influencing it.

Frequently, the operators of small water supplies have a limited knowledge of the systems that they operate and the vulnerability of their systems to contamination. Furthermore, some operators are unaware of the role of treatment systems and their modes of operation. This lack of knowledge and understanding compounds any natural and technical risks to the system, and leaves the consumers vulnerable to receiving unsafe water supplies. Numerous outbreaks of disease have occurred because of this type of complacency (see DWI, 2004; Anon, 2016) .

A core concept of water safety planning is to identify hazards. To do so, one needs to know the water supply system and hazards and events that may interfere with the distribution of safe water. Introducing WSPs, are in that regard, to move towards a risk-based surveillance. The process of implementing a WSP requires, at an early stage, “A detailed description of the water supply…to support the subsequent risk-assessment process.” (Bartram et al., 2009). Following this activity, the water supplier will have a reasonable familiarity with the water supply system. Hazards within the catchment and around the source will be mapped, and vulnerabilities within the water supply systems will have been identified. This information allows the water supplier to evaluate the risks to the system and plan their response in terms of interventions. Whilst having a detailed description of the water supply is a vital element of managing the system effectively, a deeper level of understanding will emerge from water quality surveillance. The risks identified in the WSP will inform the nature and scope of the monitoring activities, but it is the output from the monitoring activities that create a deeper understanding of the water supply system, its performance, and its vulnerabilities to surrounding hazards. As a simple example, the presence of high numbers of heterotrophic bacteria at points in the distribution system may indicate areas of stagnation that could lead to other water quality problems while rapid changes may indicate ingress or other problems associated with distribution system management and so the need for further investigation. This type of dynamic information would not be available from mapping the supply system, although it might be implied by the risk assessment.

Experience reveals the importance of an in-depth knowledge of the system to prevent outbreaks. The safe and effective operation of a water supply system requires a full understanding of the system. This understanding develops with the implementation of a Water Safety Plan and is refined by risk-based water quality surveillance.

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Case Example

Title: Development of an Inspectorate Guideline for Microbial Risk Assessment in the Netherlands by the Working group Infectious Risk: Deliberative steps towards risk-based monitoring and benefits of automated QMRA

Reference: RIVM report 2014-0020 explains how QMRA spot assesses the infection risks and addresses typical applications

Location: Netherlands

Relevant key message:Know your system

Background to the case study: The Dutch Drinking Water Act (2011), in line with the WHO GDWQ prescribes that 1. E. Coli and enterococci are absent in 100 ml drinking water and 2. The infection risk for (entero)viruses, Cryptospridium, Giardia and Campylobacter should not exceed 10.000 individuals per year due to the consumption of unboiled drinking water. However in the Drinking Water Act itself no specific directions are given on how to perform a risk assessment. In order to monitor these norms the Inspectorate Guideline 5318 (Anonymous, 2005) was drafted, describing the procedures for drinking water companies on how to conduct a Quantitative Microbial Risk Assessment for drinking water which is produced from surface water. This guideline has been developed in close collaboration with the government (Environmental Inspectorate), the Netherlands Institute for Public Health and the Environment (RIVM), the drinking water companies and drinking water laboratories, and consequently lead to the establishment of the Working group Infectious Risk (WIR) in 2000 in which all aforesaid parties are represented.

Description of case study:The main guideline provisions entail a QMRA every fourth year for the so-called index-pathogens (enterovirus, Cryptosporidium, Giardia and Campylobacter). The Guideline also defines monitoring frequencies for source waters, which depend on the drinking water production volume. In addition to regular monitoring, a number of incidental samples must be collected at moments when peak concentrations in pathogens count are assumed to occur, for example due to heavy rainfall.

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Furthermore, it describes the measurements to be done to estimate the treatment efficiencies for the four index-pathogens, based on indicator organism removal. Based on the concentration of index-pathogens in the source water combined with the reduction during treatment processes, the pathogen concentration in drinking water can be estimated. This information is required to conduct the actual quantitative microbial risk assessment, of which the procedure is also described in the Inspectorate Guideline 5318. The general principle of Inspectorate Guideline 5318 is to balance health protection and public funds. In order to standardize the QMRA process performed by the different drinking water companies, the computational tool QMRAspot has been developed by the RIVM to calculate infectious risks for the consumption of drinking water produced form surface water.

Lessons learned:It must be emphasized that risk assessment is an iterative process that is directed by practical and theoretical progress. At present, the Guideline is revised by the Working Groups Infectious Risk (WIR). The revision is based on ten years of experience in conducting QMRA for drinking water and some fundamental changes are envisioned. The most notifiable modification that is being proposed is to change the sampling scheme. In the current guideline, the number of samples is dependent on the production capacity. Proposed is to change this to a sampling schedule dedicated for individual locations. This would mean a change toward a more risk-based approach. In addition, the application of indicator organisms for the estimation of treatment efficiencies will be more flexible, since the strict application of indicator organisms as prescribed in the current Guideline does not seem to be applicable for all treatment processes. QMRA spot was adapted accordingly. A similar tool dedicated for QMRA for groundwater is currently being developed and tested with data obtained from the companies producing drinking water from groundwater, QMRA well. The revision of Inspectorate Guideline 5318 is aimed to be finished in 2019 and will be aligned with the recasted EU-DWD.

Recommendations:Risk-based monitoring and affiliated tools, like QMRA spot for drinking water produced from surface water, can systematically assess the safety and robustness of a drinking water production plant. Insights gained through QMRA can support cost-effective decision-making on treatment and corrective measures and thereby assist in keeping a balance between public funds and health protection. In the Netherlands, QMRAspot currently assists drinking water suppliers and aids policymakers and other stakeholders in prioritizing and evaluating preventive measures as an integral part of water safety plans. No extensive prior knowledge about QMRA is required by the user, because QMRA spot provides guidance on type and format of raw data, performs mathematical analysis on the raw data and then estimates the annual infectious risk for drinking water consumption. When internationally applied, these estimated risks can be compared with other e.g. production locations, the legislative standard or a local health based target. Raw data are stored in an Excel spreadsheet that can be read by the tool with Mathematica or Player Pro. A report can be automatically generated for each of the index pathogens and this report can be saved as a pdf file. The uniform approach that the tool provides promotes proper collection and usage of raw data, warrants quality of risk assessment and improves efficiency i.e. less time is required.

Author:Lieke Friederichs (contact), Saskia Rutjes, Harold van den Berg, Jack Schijven

Date: 13/04/2018

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Bibliography and further reading.Anon, (2016) Waterborne outbreak in Prague. Health Stream: Information and Analysis for Water Professionals. Issue 80, Jan 2016. P4.

Bartram, J Corrales, L., Davison, A., Deere, D., Drury, D., Gordon, B., Hoaward, G., Rhinehold, A., Stevens, M. (2009). Water Safety Plan Manual. Step-by-step management for drinking-water suppliers. World Health Organisation, Geneva.

Kozisek F. Waterborne outbreak in Prague. Public Health Bulletin of Water Research Australia Limited. Issue 80, January 2016, pages 4-6.

WHO (2017). Guidelines for drinking-water quality, 4th edition, incorporating the 1st addendum, World Health Organisation, Geneva.

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Key message 4 – “Protect rather than detect”Hazards and hazardous events represent threats to the quality of drinking water. Identifying hazards before they become a risk to public health is an essential part of surveillance.

BackgroundPublic health can be better protected by identifying and understanding of risk factors associated with the drinking-water supply. This may be particularly relevant for small water supplies. Small water supplies are often managed by communities or individuals, and are not supported financially, technically or politically in the same way as large utility-managed supplies. The costs associated with monitoring and management of water supplies are high, and therefore a robust low-cost risk assessment is invaluable for small supplies.

Small water supplies are widespread and pose a health-risk to users if not managed properly. Reports of outbreaks in Canada and the United States, for example, indicate that approximately 50% of all waterborne diseases occur in small, non-community drinking water systems (Pons et al., 2015). In Finland, outbreaks caused by norovirus and campylobacter were primarily associated with private wells and small groundwater supplies serving fewer than 500 people. In England, private water supplies serve approximately 0.5% of the population, but are responsible for 36% of waterborne disease outbreaks. Major risk factors include animals and agriculture in close proximity to rural small water systems, heavy rains and inadequate treatment (Said et.al., 2003).

Sanitary inspections (SIs) are one example of an easy-to-use tool that can be used to assist engineers, water supply manager and operators, public health officers, and regulators to identify the most important hazards, the potential for hazardous events, and pathways of contamination from catchment to consumer. Volume 3 of the WHO GDWQ, 1997, describes sanitary inspections as:

“On-site inspection and evaluation by qualified individuals of all conditions, devices, and practices in the water-supply system that pose an actual or potential danger to the health and well-being of the consumer. It is a fact-finding activity that should identify system deficiencies—not only sources of actual contamination but also inadequacies and lack of integrity in the system that could lead to contamination “(WHO, 1997).

Sanitary inspections provide an option to assess the catchment and water supply and identify the most important causes and pathways of contamination (even when there is no evidence of microbiological or chemical contamination). This information allows control options to be designed to prevent or minimize contamination to the supply. The approach can be applied more broadly to inform regional or national priorities for improving small and larger supplies. However, SIs are not the only means of identifying hazards, and particularly, hazardous events. For larger supplies where there are greater resoures and data from water quality analysis and operational monitoring, examination of the data in conjunction with different circumstances can be a valuable approach to identifying possibly hazardous events. Events, such as heavy rainfall may lead to deterioration of raw water quality that will result in a significant challenge to water treatment. Identifying such events is the first step in planning to mitigate the risks when the events happen.

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The specific functions of the sanitary inspections report, as set out in WHO (1997), are to:

- identify potential sources and points of contamination of the water supply;

- quantify the hazard (hazard score) attributable to the sources and supply;

- provide a clear, graphical means of explaining the hazards to the operator/user;

- provide clear guidance as to the remedial action required to protect and improve the supply;

- provide the raw data for use in systematic, strategic planning for improvement.

More specifically, the process of sanitary inspection is a systematic evaluation of:

1) hazards – e.g. pathogens that may have an adverse impact on the health of the people who drink the water;

2) hazardous events – e.g. rainfall - events that may introduce pathogens into the water supply or create circumstances where treatment is overwhelmed or point in distribution where rain events can cause pathogens to gain access;

3) the adequacy of the controls to prevent contamination – e.g. engineered controls, such as water treatment, non-engineered measures, such as hygiene protocols for repair works on the water distribution and simply carrying out timely repairs.

Sanitary surveying has many advantages. At its simplest, sanitary surveying is cheap, requires neither equipment nor highly-skilled staff, and may easily be performed regularly or routinely. It can reveal conditions or practices that may cause isolated pollution incidents or longer-term pollution, and the most obvious possible sources of contamination, but may not reveal all sources of contamination, for example, remote contamination of groundwater. Preventive tools, such as sanitary inspections, can form an integral part of a Water Safety Plan, particularly for small supplies, but sanitary inspection is not the only tool available. The principles of sanitary surveying can also be used to develop larger scale assessmets for larger water supplies but these are more easily supported by a range of other tools that are available because such supplies are generally better resourced. For larger supplies, with greater resources mapping the larger catchment an mapping the supply system from source to tap is also an important tool in identifying hazards, the nature of the hazardous event and where and how they occur.

Case Example Title: Rapid assessment of drinking water quality and prevailing sanitary conditions in small-scale water supply systems in rural areas in SerbiaCase study number: CS1

Location: The Republic of Serbia

Relevant principle: Risk-based drinking-water quality surveillance is a proactive approach to monitoring and controlling critical risks in the water supply. It directs water quality monitoring towards the most important, relevant parameters for system performance and public health protection. It also justifies derogation from regulated parameters and sampling frequencies.

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Risk-based drinking-water quality surveillance design tools, including sanitary surveys, partially compensate a lack of dedicated laboratory facilities and can improve overall water quality monitoring efforts where resources are limited.

Background to the case study:Drinking-water quality monitoring in rural areas in Serbia is an integral part of the national "Programme on the Protection of the Population Against Infectious Diseases". It is being conducted by the network of the institutes of public health under the Ministry of Health. The drinking water quality parameters and sampling frequency are regulated by the Rule on Hygienic Correctness of Drinking-water ("Official Gazette of SRJ", no. 42/98) for the water supplies that serve more than 20 people (or 5 households). However, the enforcement is weak in rural areas, which resulted in a lack of data on water quality and prevailing sanitary conditions in small-scale water supply systems (SSWSs). Existing challenges such as unregulated ownership of the numbers of rural small water supplies, the lack of responsibility for maintenance and monitoring of facilities, as well as for testing the quality of drinking water hamper the drinking-water quality surveillance.

Absence of a legal entity in managing these water supply systems prevents operation of the sanitary inspection. Maintenance is not supported by the necessary attention, double connections in some households and various illegal connections increase the risk of water contamination, which pose potential risk to health of rural population.

The Republic of Serbia has used the target setting framework under the Protocol on Water and Health to address SSWSs challenges and close the knowledge gaps risk-based drinking-water quality monitoring. Serbia’s national targets set under the Protocol include a specific target on undertaking a systematic assessment of drinking-water quality and prevailing conditions in rural water supplies in order to improve the evidence base on rural water supply and enable informed decision-making.

Description of case study:

A national-level systematic survey was conducted in rural areas of Serbia in 2016 based on a rapid assessment methodology developed by WHO. Two types of water supply technologies were investigated: (i) small piped systems serving up to 10 000 people; and (ii) individual supplies which, according to national standards, comprise systems serving less than five households or 20 inhabitants. In total, 1318 small-scale water supply systems were inspected (1136 piped systems and 182 individual supplies) and 1350 drinking-water samples were taken and analyzed for one microbiological parameter (i.e. Escherichia coli – E.coli) and 10 physico-chemical parameters (i.e. ammonia, arsenic, chlorine residual, colour, electrical conductivity, hydrogen ions – pH, manganese, nitrate, odour and turbidity). The survey findings clearly show a significant water-quality gap between urban and rural areas (Fig.1).

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Urban water supply systems Piped systems in rural areas Individual supplies in rural areas

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Urban water supply systems Piped systems in rural areas Individual supplies in rural areas

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Urban water supply systems Piped systems in rural areas Individual supplies in rural areas

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Fig. 1. Microbial and physico-chemical compliance with national water quality standards in rural and urban water supplies in Serbia

One third of all water samples taken from SSWSs in rural areas were found to be microbiologically contaminated, correlating with identified sanitary risks and unsolved ownership of the large number of small-scale water supply systems. The dominant sanitary risks revealed by sanitary inspection were: absence of regular chlorination, non-established and unmanaged sanitary protection zones, sources of pollution (latrines, sewers, animal breeding, cultivation, roads, industry, rubbish and other sources) placed nearby and unsatisfactory technical conditions.

Lessons learned: Rapid assessment methodology enabled the identification of the most important causes of

contamination and prioritization for the improvement. It served the public health authorities to identify systems that required increased attention and guidance.

This survey has helped the public health institutes to establish systematic baseline information on small-scale systems in their area of responsibility, increase attention to the challenges related to such systems, and leverage local action towards their improvement.

It provided useful baseline information on drinking water quality in local or national context, that can be utilized for national target setting and revising or for prioritizing surveillance efforts.

In the absence of national inventory of small-scale systems in rural areas, the data obtained through the rapid assessment, including development of study design, can complement the national data needed for investment and financial planning the implementation of Water Framework Directive, particularly EU Drinking Water Directive.

The survey has induced policy actions and measures for the improvement of rural water supplies. These are directed at amendment and enforcement of existing legislation and programmes, as well as development of new regulations.

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The survey makes a strong contribution for designing further education programmes in hygiene and sanitation.

Recommendations:The survey results point to the need for: (i) integration of the Water Safety Planning (WSP) approach in a regulation and its implementation to ensure safe drinking water from source to tap; (ii) increased enforcement of the regulation on foundation and ownership of water supply systems; (iii) development of national and local action plans for improving small-scale systems serving rural populations, and (iv) establishment of a national inventory of small-scale systems that would provide a systematic overview of water supplies in rural areas and effectively support programming of improvement interventions.

References1. Jovanović DD, Paunović KZ, Schmoll O, Shinee E, Rančić M, Ristanović-Ponjavić I, the National

Expert Group. Rapid assessment of drinking water quality in rural Serbia: overcoming the knowledge gaps and identifying the prevailing challenges. Public Health Panorama. 2017; 3(2):141-356.

2. Rapid assessment of drinking-water quality: a handbook for implementation. Geneva: World Health Organization; 2012

3. Jovanovic D, Veljkovic N (eds.). Implementation of the Protocol on Water and Health in the Republic of Serbia – situation analysis. Water and Sanitary Technology. 2015;2:5-10.

Author: Dragana Jovanovic Date: 10/07/2017

Bibliography and further reading.

Bartram, J. et al., (2009). Water safety plan manual. Step-by-step management for drinking-water suppliers. World Health Organisation. Geneva.

Lloyd, B and Helmer, R. (1991). Surveillance of drinking water quality in rural areas. Longman Scientific and Technical. England.

Pons W., Young, I., Truong, J., Jones-Bitton, A., McEwen, S., Pintar, K., Papadopoulos, A. (2015). A Systematic Review of Waterborne Disease Outbreaks Associated with Small Non-Community Drinking Water Systems in Canada and the United States. PLOS One 10(10): e0141646. https://doi.org/10.1371/journal.pone.0141646.

Said B. et.al., (2003). Outbreaks of infectious diseases associated with private drinking water supplies in England and Wales 1970-2000. Epidemiol Infect. 130:469-79

WHO (1997) Guidelines for drinking-water quality, volume 3, Surveillance and control of community supplies. 2nd edition. World Health Organisation, Geneva.

WHO Regional office for Europe (2016). The situation of water-related infectious diseases in the pan-European region. Copenhagen. Denmark

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Key message 5 – “Don’t monitor what is not there”Risk-based drinking-water quality surveillance directs water quality monitoring towards the most important, relevant parameters for system performance and public health protection.

BackgroundRisk-based drinking–water quality surveillance provides a systematic methodology for the identification, evaluation and control of risks in drinking-water supply systems.

There are inherent difficulties with relying on retrospective water quality measurements to assess water safety. For example, the assessment of microbiological safety based on indicator bacteria has limited value as indicators of health risk. Faecal indicator bacteria are not as robust as some pathogens and there is no direct correlation between numbers of indicators and enteric disease (Bartram and Godfrey, 2015; Taylor, 2015). By monitoring and reporting of chemical parameters, without a mapping or assessment of the presence of these parameters, there is a high risk of misusing resources, as the results will not add information that serves the purpose of protection the public health.

To avoid a misuse of resources, especially when they are scarce, it is needed to establish criteria for prioritizing core parameters that are of public health significance. To be effective, in this situation, requires that one focuses on the actual occurrence of substances representing a hazard to human health. For example, chemicals known to cause health effects should initially be considered in a monitoring program. However, it does not mean that they should necessarily be monitored. There needs to be consideration of criteria before including a list of parameters subject to routine monitoring, with the basis of health concern. The choice of parameters needs also to take account of variations in occurrence and concentration, as well as circumstances such as the use of chlorine and extraction of groundwater or surface water. Frequency of monitoring should reflect the risk of a breach of a standard or guideline value. Mitigation may reduce the need for monitoring, however, all decisions concerning choice of parameters and frequency of monitoring should be justified and documented. These considerations are key elements of risk-based approaches to surveillance.

A proactive approach prevents and controls the risk from harmful events and allows risk and control measures to be prioritised. If the contamination is prevented from reaching the source, failures in the drinking-water treatment plant, would be of less risk for contaminated water reaching the consumer. The identification and prioritisation of the risks also allows monitoring to be better directed towards those parameters which have been shown to be of particular relevance to the water supply being managed, rather than just monitoring for regulated parameters. More importantly, protection of raw water sources reduces the risks of contamination of the drinking water in case of failure in the water treatment. It is used to establish whether there is a risk of non-compliance with any relevant standards or indicator parameter values. The risk assessment should also be used as part of the information to consider whether it is possible to exclude parameters from the audit monitoring requirements. In the long term, this will contribute to a reduction in costs and the consistent safety and acceptability of drinking water throughout the supply chain in all supplies (Taylor, 2017).

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Case Example

Jersey (in the Channel Islands) primarily uses surface water as groundwater sources on the Island are very limited and there is a fluctuating population with a higher population during the summer holiday months when tourist numbers increase. The Island has limited heavy or manufacturing industry but does have an extensive agriculture, including dairy based around the famous Jersey cows and a significant distinctive early potato growing industry (Jersey Royals). The problems of raw water contamination relate to microbiological contamination from agriculture and also septic tanks and chemical contamination with nitrate and a range of pesticides. Most of the results of extensive chemical monitoring to meet the requirements of the UK Drinking Water Regulations adopted in Jersey Law resulted in non-detects or very low levels of chemicals, but the cost of monitoring was significant. A risk-based approach to monitoring was introduced, which reduced the number of determinations and the cost of carrying out that monitoring by over 50%. However, the problem of raw water contamination with pesticides remained and the reduction in cost of the monitoring programme released funds to increase the monitoring of raw water which allowed better management of quality by changing streams from which water was abstracted into reservoirs and also identification and management of historic contamination by pesticides that were no longer used. The data were also pivotal in persuading the agricultural industry to adopt better catchment practices to prevent or minimise contamination.

I was of the impression that we had an example of Hungary and chemicals – or not submitted?

England and Wales

While monitoring is a requirement of the Private Supply Regulations (England) 2016, sampling and analysis alone cannot provide assurance about the safety of a private water supply. A key aspect of the Regulations is the requirement placed on each local authority to carry out a risk assessment of each private water supply in its area at least every five years. The monitoring of each private water supply must be based on the outcome of the regulatory risk assessment carried out for that supply.

The relevant parameters and frequency of sampling should reflect the risk rating and the nature of the hazards identified in the risk assessment. In this regard, it is coliforms and E. coli (ingress into the network or poor hygienic conditions, especially tanks); colony counts (upward trend may indicate deterioration of water quality); conductivity, pHand turbidity; zinc and iron (from corrosion of galvanised steel or cast iron pipes), manganese, and odour (ingress and permeation of plastic pipes); trihalomethanes and bromate (disinfection by-products) (if there is chlorination within the private distribution network); lead, copperand nickel (from the pipe work or tap fittings in the private distribution network or within the premises. (DWI, 2016).

Bibliography and further reading.

Bain, R., Cronk, R., Wright, J., Yang, H., Slaymaker, T., and Bartram, J. (2014). Fecal contamination of drinking-water in low- and middle-income countries: A systematic review and meta-analysis. PLOS Medicine, 11(5), e1001644.

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Bartram, J. and Godfrey, S. (2015). Drinking water supply. In: Bartram, J., with Baum, R., Coclanis, PA., Gute, DM., Kay, D., McFayden, S., Pond, K., Robertson, W. and Rouse, MJ (eds). Routledge Handbook of Water and Health. London and New York: Routledge.

DWI (2016). http://dwi.defra.gov.uk/private-water-supply/regs-guidance/Guidance/info-notes/england/reg-6.pdf (accessed 08/05/2018)

Taylor, H. (2015). Water monitoring and testing. In: Bartram, J., with Baum, R., Coclanis, PA., Gute, DM., Kay, D., McFayden, S., Pond, K., Robertson, W. and Rouse, MJ (eds). Routledge Handbook of Water and Health. London and New York: Routledge.

 

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Key message 6 – “Water quality monitoring is too little, too late”Water quality monitoring is an essential part of surveillance. However, water quality monitoring alone cannot ensure safety of the water supply system.

BackgroundOne of the primary concerns of water suppliers is to ensure that the drinking water they supply does not pose an unacceptable risk to the health of consumers. To achieve this, suppliers monitor and refer to national standards or international guidelines that define the admissible concentrations of a range of biological, chemical and physical parameters.

Drinking-water quality monitoring refers to the sampling and analysis of water constituents and conditions. It is a measure of the physical, chemical, biological characteristics of water, which can provide practical evidence to support decision-making on health and environmental issues. The main reasons for monitoring drinking-water quality are:

• to determine that water supplied to consumers does not present a risk to health, by confirming that the supply system is being operated within pre-determined parameters; and

• to provide confirmatory evidence that the water was safe after it was supplied. This includes monitoring for compliance.

to alert us to current, ongoing, and emerging problems; to determine compliance with drinking water standards.

to protect other beneficial uses of water. Assessments based on monitoring data help to measure effectiveness of water policies,

determine if water quality is getting better or worse, and formulate new policies to better protect human health and the environment. (Myers, no date) Yet used in isolation, retrospective drinking water quality monitoring provides too little information too late. Therefore, although day-to-day monitoring is important, as the sole method for defining the performance and safety of a water supply system, this type of water quality monitoring is flawed. It is only when such monitoring is integrated into a comprehensive risk-based surveillance programme that its value is fully realised.

Alternatively, or in parallel with the comprehensive monitoring programme, indicators of water quality (such as turbidity) can be measured to assess the potential presence of a contaminant. If the water does not breach the admissible concentrations, or is free of indicators, water suppliers consider that the water is safe. In these circumstances, water quality monitoring is being used to define the performance of the water supply system. However, compliance to microbiological indicator bacteria does not imply free of contamination (Sobsey, 1989).

The regulatory framework that drives the activities of water suppliers frequently defines the number of samples taken and the frequency of sampling. The WHO GDWQ (WHO, 2011) and the EU Drinking-Water Directive (EU, 1998; 2015)), for example, recommend increasing the sampling frequency and the number of samples as the population supplied increases. For large water supplies under the control of water authorities, sample numbers are large, and the frequency of sampling is high. But at the opposite end of the scale populated by small water supplies, the number of samples can be small

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– often a single sample – and the frequency of sampling extremely low – often once every few years. In the interval between sampling events the quality of the water is unknown.

Water quality and treatment processes are often affected by seasonal changes or sudden operational shifts, such as a pipe break or flooding. By testing at intervals defined by regulations, intervening events such as seasonal sampling, are likely to be missed. For example, typical seasonal changes in a surface water source cause the turbidity to increase and represent a situation where one expects a high load of organic material, possible pathogenic, transferred to the source. E.g. in Norway, the requirements for monitoring the raw water source is in some cases a minimum of four times a year. However, despite the purpose being that these four samples should represent the changes over the year, it is likely that these events are missed if the sampling dates are fixed. This is illustrated in 2.

Figure 2 Seasonal changes in turbidity of a surface water source.

Another level of uncertainty occurs in the interval between the time the sample was taken and when the analytical results are returned to the water supplier. The time between taking the sample and receipt of the analytical result varies due to several factors, including the time it takes to carry out the test. For some chemical parameters analysis can be quite quick (less than one hour), but others can take longer. Of greater concern is the time taken to complete the tests for microbial parameters, which can be up to 48 hours for the routine indicators of faecal contamination. The implications of this delay are profound: by the time contamination has been identified, consumers will have been exposed to pathogens and may already be displaying signs of illness. Hence, monitoring in this context represents a retrospective check of quality, or provision of a long-term perspective of the water quality trend rather than a proactive demonstration of safety.

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Winter Spring Summer Autumn

Drinking-water quality surveillance driven solely by the imperative to demonstrate compliance with parameter values will always be subject to unforeseen circumstances resulting from fluctuating concentrations of parameters. A sample can only represent the quality of the water at the time and location the sample was taken. The quality of the water before and after the sample was taken can only be assumed. Given the long interval between sampling events for small water supplies, the sampling frequency is too little to be effective. Furthermore, the time taken for analytical results to be returned to the water supplier can result in consumers being exposed to the contamination before the contamination has been recognized. Analytical results are often received too late to protect public health.

In addition to the limitations imposed by rigid sampling regimes, making judgements from the presence or absence of certain parameters is not straightforward. The GDWQ prioritize the microbial safety of water, due to the immediate and potentially widespread consequences of pathogens being present in the supply. The pathogens that have been of greatest concern in drinking-water are those excreted in faeces, and are transmitted by the faecal-oral route. This group of pathogens includes microorganisms from all families: bacteria, viruses, and protozoa. Standard, routine methods for testing the microbial safety of water use a group of bacteria that are ubiquitous in faeces, but in themselves are not pathogens; namely, the coliform group of bacteria (which includes E.coli) and the enterococci. Their purpose is to indicate the presence of faecal contamination, and therefore the risk that pathogens may be present in the water.

Case Example

Any suggestion? If not, I think we could just leave to lay-out (picture)

Bibliography and further reading.EU (1998). Council Directive 98/83/EC of 3 November 1998 on the quality of water intended for human consumption .

Official Journal L 330 , 05/12/1998 P. 0032 – 0054.

EU (2015). Commission Directive (EU) 2015/1787 of 6 October 2015 amending Annexes II and III to Council Directive 98/83/EC on the quality of water intended for human consumption

Fleisher, J.M. 1985. Implications of coliform variability in the assessment of the sanitary quality of recreational waters. Journal of Hygiene 94(2):193-200.

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Fleisher, J.M. 1990. The effects of measurement error on previously reported mathematical relationships between indicator organism density and swimming-associated illness: A quantitative estimate of the resulting bias. International Journal of Epidemiology19(4):1100-1106.

Medema, G.J., Payment, P., Dufour, A., Robertson, W., Waite, M., Hunter, P., Kirby, R. and Anderson, Y. 2003. Safe drinking water: an ongoing challenge. In: Assessing Microbial Safety of Drinking Water - Improving approaches and methods, edited by Dufour, A., Snozzi, M., Koster, W., Bartram, J., Ronchi, E. and Fewtrell, L. London: IWA.

Myers, D (no date). Why monitor water quality? https://water.usgs.gov/owq/WhyMonitorWaterQuality.pdf

Payment, P. 1998. Distribution impact on microbial disease. Water Supply 16:113-119.

Sobsey, M.D. (1989) Inactivation of health related microorganisms in water by disinfection processes. Water Science and Technology. 21(3):179-195.

Stevens, M., Ashbolt, N. and Cunliffe, D. (2003). Recommendations to change the use of coliforms as microbial indicators of drinking water quality. National Health and Medical Research Council. ISBN: 1864961651, Online ISBN: 1864961597.

WHO (2011). Guidelines for Drinking-water Quality. Fourth Edn. World Health Organisation, Geneva.

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Key message 7 – “Surveillance improve the preparedness of water supplies”Risk-based surveillance increases the resilience of water supply systems to changing risks.

BackgroundGlobally, water-related disasters already account for 90% of all natural disasters (WWDR4, 2012). Due to climate change their frequency and intensity is rising. Damages attributed to water-related disasters can be up to 15% of annual GDP for certain countries (Vlaanderen, 2015). Flooding occurred in 50 of the 53 Member States in the in the WHO European Region during the past decade (Menne & Murray, 2013). Since 2000, 400 registered large-scale flood events caused deaths of more than 2000 people, affected 8.7 million others and generated 72 billion EUR losses (Guha-Sapir et.al., 2015).

Population growth, poverty, land shortages, urbanization, the poor condition of flood protection and drainage infrastructure, and water storage facilities, have increased the vulnerability of people to extreme weather events and, multiplied impacts on public health associated with water-borne epidemics. Climate change models predict decreases of renewable water resources in some regions and increases in others, with large uncertainty in many places.

Risk reduction, preparation and prevention are sensible investments that pay off in terms of reduced loss of life, avoided damage, and long-term economic growth and stability..

Risk-based surveillance supports both strategic and operational decision-making. Drinking-water technologies are potentially vulnerable to climate and environmental changes. Adaptive risk management systems such as Water Safety Plans can effectively assess and manage risks posed by climate change (Bartram et al. 2009). Those responsible for drinking-water safety need to have a good understanding of how climate change is affecting water resources and thus drinking-water supply systems to inform changes to policies, programmes and infrastructure to prepare for and cope with changing freshwater quantity and quality (WHO, 2017).

Adapting the WSP approach in order to incorporate the expertise of climatologists to help predict the conditions under which a water system may need to cope will help to increase the adaption and resilience of water supply systems to climate change. With climate change in mind, the WSP team should consider the types of hazards that might become more problematic within the local context with reference to general checklists of hazards, hazardous events and control measures.

Long-term planning is required for continuing access to freshwater sources; managing water demand among competing needs; reviewing the resilience of the supply system itself; addressing policy needs, such as for water storage and flood control; implementation of control measures to ensure water quality (and quantity). The WSP process provides an effective framework to systematically address these requirements (WHO, 2017).

Prioritising the development of risk-based surveillance programmes is likely to be critical to promoting more effective and resilient water supplies, but will require the development of new tools

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to support predicted trends in climate change and effects on drinking water quality and sufficiency. This would facilitate local level assessments that ultimately will be required to help build resilience and identify adaptations (Howard et al., 2010).

The principles and practice of water safety planning, requires risks to drinking-water safety and security to be identified, prioritized and managed before problems occur. It is therefore a useful tool to address the impacts of climate change.

Case Example

Title: Early warning systems in outbreak prevention – case example of a drinking water outbreak in Miskolc following an extreme precipitation eventCase study number: CS3

Location: Miskolc, Hungary

Relevant principle:Risk-based surveillance increases the resilience of water supply systems.Background to the case study: Miskolc is a city of approximately 80000 inhabitants located in North-Eastern Hungary. It relies on karstic water for its drinking water supply. Following an extreme precipitation event, it experienced a multi-etiological drinking water outbreak affecting over 3500 people.

Description of case study:The water of the karstic spring is generally delivered without treatment, except for safety chlorination. The water supply was monitored regularly according to the frequency defined in the drinking water legislation. Samples were tested routinely for turbidity, microbiological and chemical parameters. During a week of extreme precipitation, increased turbidity was observed, but as fecal indicators were not detected, normal operation was continued. Following the 3-day Pentecost holiday, the water supply was resampled, but by the time the results arrived (two days later), general practitioners already reported increased incidence of gastrointestinal illness. Boil water advice was given and the consumption of water restricted. The advice was upheld until the operation of the water supply returned to normal, and the whole system was disinfected. Epidemiological investigation confirmed the consumption of tap water as the source of infection.Lessons learned:The cause of the outbreak was the extreme precipitation that changed the underground current in

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the karst and washed contamination into the water source. Routine testing for faecal indicators was insufficient in preventing the outbreak. Turbidity was found to be indicative of events leading to the deterioration of water quality. Online turbidity monitors were installed, and a control value was assigned to the measurements as an early warning of potential contaminations. A rapid method for E. coli testing was also introduced. Recommendations:Supply operators should introduce simple operational control points for early detection and water incidents and appropriate interventions. Author: Márta Vargha Date: 23/05/2017

Bibliography and further reading.Bartram, J., Corrales, L., Davison, A., Deere, D., Drury, D., Howard, G., et al. (2009) Water safety plan manual: step-by-step risk management for drinking water suppliers. Geneva: World Health Organisation.

Howard, G., Calow, R., Macdonald, A. and Bartram J. (2016) Climate Change and Water and Sanitation: Likely Impacts and Emerging Trends for Action. Annual Review of Environment and Resources 2016 41:1, 253-276

Howard, G., Charles, K., Pond, K., Brookshaw, Houssain and Bartram, J. (2010) Securing 2020 vision for 2030: climate change and ensuring resilience in water and sanitation services. Journal of Water and Climate Change,

Menne B, Murray V (2013). Floods in the WHO European Region: health effects and their prevention. Copenhagen: WHO Regional Office for Europe

Vlaanderen, N. 2015. Water-related risk reduction: tools to implement a preventive approach. http://www.un.org/waterforlifedecade/waterandsustainabledevelopment2015/pdf/OP_Governments_Risks_Niels_Vlaanderen_FORMAT.pdf

WWDR4, 2012. http://unesdoc.unesco.org/images/0021/002156/215644e.pdf

WHO/IWA (2009). Water safety plan manual (WSP manual). Step-by-step risk management for drinking-water suppliers. World Health Organization; International Water Association.

WHO (2011). Guidelines for Drinking-water Quality. Fourth Edition. World Health Organisation, Geneva.

WHO (2017) Climate-resilient water safety plans: managing health risks associated with climate variability and change. WHO: Geneva. http://apps.who.int/iris/bitstream/handle/10665/258722/9789241512794-eng.pdf;jsessionid=B461FACB9FA87556D5EABF2A960272D7?sequence=1

WHO Regional Office for Europe (2017). Protecting health in Europe from climate change: 2017 update. Copenhagen WHO Regional Office for Europe; 2017

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(http://www.euro.who.int/__data/assets/pdf_file/0004/355792/ProtectingHealth EuropeFromClimateChange.pdf?ua=1)

WHO Regional Office for Europe (2017).Flooding: Managing Health Risks in WHO European Member States. Copenhagen WHO Regional Office for Europe; 2017 ( http://www.euro.who.int/__data/assets/pdf_file/0003/341616/Flooding-v11_ENG-web.pdf?ua=1)..

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Key message 8 – “Trustful communication of risks is important to ensure water safety”Strategies for effective communication at all levels is an integral element of surveillance. Trustful communications and involvement of the community serves to detect and inform about risks in the water supply.

BackgroundAn essential part of a surveillance programme is the reporting of results to stakeholders. This will support the development of effective mitigation and intervention strategies. Stakeholders may include public health officials, local administrations, communities and water users, local regional and national authorities responsible for development planning and investment.

Effective communication helps to increase awareness and knowledge of drinking-water issues and areas of responsibilities. This helps consumers to understand and contribute to decisions about the service provided by a drinking-water supplier or land-use constraints in a catchment. In addition, effective communication by consumers allows their expectations to be met.

Effective communication requires conveying or transmitting information between parties. Interested parties include government, agencies, corporations and industry groups, unions, the media, scientists, professional organisations, interested groups, and individual citizens (Covello et al. 1991). Its goal can vary. Communication can be used simply to share information, or to change people’s belief or change behaviour. To be adequate, communications must contain the information that users need, connect users with that information, and be understood by users (Fischhof, 2011).

It is vital to have an effective communication and coordination strategy, to report results back to stakeholders and is particularly important when investigating a possible drinking-water contamination incident, to mitigate significant public health and economic consequences. As detailed in the WHO Guidelines for Drinking-water Quality (2017), proper reporting and feedback will support the development of effective remedial strategies. The ability of the surveillance programme to identify and advocate interventions to improve water supply is highly dependent on the ability to analyse and present information in a meaningful way to different target audiences.

Communication strategies should include (list not exhaustive):

- Adequate training of staff to ensure that all members of the surveillance team are familiar and understand the significance of day-to-day activities as well as what to do in an emergency situation. Staff must be trained in and understand the significance of their roles.

- Reporting results and the significance of the results of monitoring activities to relevant stakeholders.

- Summary information to be made available to consumers – for example, through annual reports and on the Internet;

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- Procedures for rapidly advising stakeholders of any significant incidents within the drinking-water supply, including notification of the public health authority. This may be through the media or face-to face;

- Liaison with communities, suppliers media and regional authorities; - Establishment of mechanisms to receive and actively address community complaints in a

timely fashion. - The use of surveillance data for policy improvements

It may be appropriate to use community organizations such as local councils and community-based organizations, such as women's groups, religious groups and schools to provide a mechanism of relaying important information to a large number of people within the community. Furthermore, by using local organizations, it is often easier to initiate a process of discussion and decision-making within the community concerning water quality. The most important element in working with local organizations is to ensure that the organization selected can access the whole community and can initiate discussion on the results of surveillance (WHO, 2017).

If communication is not effective both within surveillance agencies and between the agencies and users, then there is danger of serious public health impacts and loss of consumer confidence. There is evidence of this occurring on numerous occasions.

As well as day-to-day running of water utilities, communication forms a key component of emergency plans which should be developed by water suppliers. These plans should consider potential natural disasters (e.g., earthquakes, floods, damage to electrical equipment by lightning strikes), accidents (e.g., spills in the watershed), damage to treatment plant and distribution system and human actions (e.g., strikes, sabotage). Emergency plans should clearly specify responsibilities for coordinating measures to be taken, a communication plan to alert and inform users of the drinking-water supply and plans for providing and distributing emergency supplies of drinking water (WHO, 2004).

Case Example

Any suggestions?

Bibliography and further reading.Barrell, RAE., Hunter, PR and Nichols, G. (2000). Microbiological standards for water and their relationship to health risk. Communicable Disease and Public Health; 3: 8-13.

Corvello, V.T. (1991) Risk comparison and risk communication: issues and problems in comparing health and environmental risk. In Communicating Risks to the Public (eds R.E. Kasperson and P.J.M. Stallen), pp. 79–118, Kluwer, Dordrecht.

Fischoff, B (2011). Communicating Risks and Benefits: An Evidence-Based User’s Guide. http://www.fda.gov/ScienceResearch/SpecialTopics/RiskCommunication/default.htm

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WHO (2004). Guidelines for Drinking-water Quality. Third Edition, vol 1 Recommendations. WHO: Geneva.

WHO (2017). Guidelines for Drinking-Water Quality: Fourth Edition Incorporating the First Addendum.

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