A Guide To Hazard Identification Risk Assessment For Drinking Water Supplies

In 2004, the WHO Guidelines for Drinking Water Quality recommended that water suppliers develop and implement "Water Safety Plans" (WSPs) in order to systematically assess and manage risks. Since this time, governments and regulators, water suppliers and practitioners have increasingly embraced this approach, but they have also requested further guidance. This much-anticipated workbook answers this call by describing how to develop and implement a WSP in clear and practical terms. Stepwise advice is provided through 11 learning modules, each representing a key step in the WSP development and implementation process: 1. Assemble the WSP team; 2. Describe the water supply system; 3. Identify hazards and hazardous events and assess the risks; 4. Determine and validate control measures, reassess and prioritise the risks; 5. Develop, implement and maintain an improvement/upgrade plan; 6. Define monitoring of the control measures; 7. Verify the effectiveness of the WSP; 8. Prepare management procedures; 9. Develop supporting programmes; 10. Plan and carry out periodic review of the WSP; 11. Revise the WSP following an incident ; Every Module is divided into three sections: 'Overview', 'Examples and Tools', and 'Case studies'. The overview section provides a brief introduction to the Module, including why it is important and how it fits into the overall WSP development and implementation process. It outlines key activities that should be carried out, lists typical challenges that may be encountered, and summarizes the essential outputs to be produced. The examples and tools section provides resources which could be adapted to support the development and implementation of WSPs. These resources include example tables and checklists, template forms, diagrams, or practical tips to help a WSP team address specific challenges. These are often example outputs and methodologies adapted from recent WSP experiences. Each Module concludes with case studies so the reader can benefit from lessons-learned from real-life experiences. They are intended to make WSP concepts more concrete and to help readers anticipate issues and challenges that may arise. The descriptions were drawn from WSP initiatives in Australia, the Latin American and the Caribbean region (LAC), and the United Kingdom.

"The WHO Guidelines for Drinking-water Quality recommends the application of a comprehensive risk assessment and risk management approach called Water Safety Plans (WSPs) to most effectively ensure the safety of drinking-water supplies. The WSP approach is systematic, comprehensive, cost-effective and appropriate in a wide range of circumstances and thus are an important tool for small community water supplies. This manual is designed to engage, empower and guide communities in the WSP development and implementation process. Guidance is provided on how to develop and implement a WSP through six achievable tasks. By following the WSP approach as described in this manual, small communities can improve the management of their drinking-water systems to achieve incremental and sustainable improvements in their drinking-water quality."--Publisher's description.

Water risks and security are a major global hazard in the 21st century and it is essential that water professionals have a solid grounding in the principles of preventative risk management. This second edition of the key textbook, Risk Management for Water and Wastewater Utilities, extends beyond first principles and examines the practicalities of resilience and vulnerability assessment, strategic risk appraisal and the interconnectedness of water utility risks in a networked infrastructure. It provides an up-dated overview of tools and techniques for risk management in the context of the heightened expectations for sound risk governance that are being made of all water and wastewater utilities. Risk Management for Water and Wastewater Utilities provides a valuable starting point for newly appointed risk managers in the utility sector and offers MSc level self-paced study with self-assessment questions and abbreviated answers, key learning points, case studies and worked examples.

Contamination of drinking-water is a significant concern for public health throughout the world. Microbial hazards make the largest contribution to waterborne disease in developed and developing countries. Nevertheless, chemicals in water supplies can cause serious health problems--whether the chemicals are naturally occurring or derive from sources of pollution. At a global scale, fluoride and arsenic are the most significant chemicals, each affecting perhaps millions of people. However, many other chemicals can be important contaminants of drinking-water under specific local conditions. Often, identification and assessment of risks to health from drinking-water relies excessively on analysis of water samples. The limitations of this approach are well recognized, and contributed to the delay in recognizing arsenic in drinking-water as a significant health concern in Bangladesh and elsewhere. To overcome such limitations, the latest edition of the World Health Organization (WHO) Guidelines for Drinking-water Quality (WHO, 2004; WHO,2006) emphasizes effective preventive management through a 'framework for drinking-water safety' that incorporates 'water safety plans.' Effective preventive management of chemicals in drinking-water requires simple tools for distinguishing the few chemicals of potential local or national concern from the unmanageably long list of chemicals of possible significance. The aim is to identify and prioritize the chemicals of concern, to overcome the limitations of direct analysis of water quality, and ensure that limited resources are allocated towards the monitoring, assessment and control of the chemicals that pose the greatest health risks. Identifying and prioritizing chemical risks presents a challenge, especially in developing countries, because information on the presence of chemicals in water supplies is often lacking. This document provides guidance to help readers to meet that challenge. It shows how information on aspects such as geology and industrial and agricultural development, which is often readily available, can be used to identify potential chemical contaminants (and potential sources of chemicals), from catchment to consumer, and thus prioritize risks. As a supporting document to the Guidelines for Drinking-water Quality (WHO, 2004; WHO, 2006), this publication is aimed at policy-makers, regulators, managers and public health practitioners at national and local level. It is divided into three parts: Part A provides general guidance on using limited information in prioritizing chemicals in drinking-water for risk management. The need for such guidance is outlined in Chapter 1,which also describes the administrative and policy context. Chapter 2 describes the principles applied in prioritizing chemicals, provides information on some factors that affect chemical concentrations along pathways, and highlights several specific chemicals that are frequently considered priorities because of their widespread occurrence or significant health effects. Chapter 3 discusses the role of drinking-water standards and guidelines, and provides an overview of contemporary water quality management procedures. Part B provides practical guidance on identifying specific chemicals that are likely to be of concern in individual water supply systems. It groups chemical contaminants into five categories on the basis of their potential sources: naturally occurring, from agriculture activities, from human settlements, from industrial activities, and from water treatment and distribution processes themselves. Part C comprises the appendices. It includes guidance on the most likely sources of potential contaminants and on identifying chemicals that could be of concern in particular circumstances. The appendices address potential sources of chemicals considered in the WHO drinking-water guidelines (WHO, 2004; WHO, 2006), chemicals potentially discharged in effluents from industrial sources, and the association of pesticides with crops and crop types. This information is presented in an accessible format that will help users to determine the chemical hazards that can arise in the catchment, in treatment and in distribution, in large, medium and small water supplies. Many experts worldwide contributed to this work over a period of several years, beginning with the 1st Meeting of Experts on Monitoring Chemicals in Drinking Water, held in Bangkok, Thailand, in January 2001. This was followed by the 2nd Meeting of Experts on Monitoring Chemicals in Drinking Water, also held in Bangkok, in December 2001. Both meetings were sponsored by WHO and hosted by the Department of Health, Ministry of Public Health, Thailand. The draft guidance document was subsequently tested in a series of field trials in 2002-2003 in Indonesia, Fiji, Nepal, Mongolia, the Philippines and Thailand. Lessons learnt through the field trials provided feedback that was valuable in revising and finalizing the document. Readers should note that while this publication has been developed as a supporting document for, and with reference to, the Guidelines for Drinking-water Quality, the guidelines themselves are frequently updated and the latest information should always be sought by reference to relevant World Health Organization publications and web site. (http://www.who.int/water_sanitation_health/dwq/guidelines/en/index.html).

The management of small water supplies presents a unique challenge globally, in countries at all stages of development. A combination of lack of resources, limited understanding of the risks and poor expertise means that individuals and communities may face serious health risks from these supplies. This is not only due to microbiological contamination, but also from contamination by metals, either due to natural or man-made contamination of the source water or through leaching from plumbing materials due to inadequate conditioning and corrosion inhibition and use of inappropriate materials. This Best Practice Guide aims to share best practice and experience from around the world on a practical level. It looks at general issues relating to small supplies and ways of managing these, adopting a Water Safety Plan approach to deliver sound and lasting improvements to quality. Management techniques and treatment relating to specific metals will be covered, from a theoretical and practical perspective, to deliver a publication that will act as an authoritative guide for all those faced with the problem of ensuring the quality of a small water supply. Varied case-studies will help to illustrate issues and ways in which they have been resolved. Table of contents The Difficulties of Managing Water Quality in Small Water Supplies; What are Small Supplies?; The Management and Regulation of Small Water Supplies; The Vulnerability of Small Water Supplies to Contamination by Metals; Water Safety Plans for Small Water Supplies; Making WSPs Work for Small Supplies; Teamwork- The Value of a WSP Team; A Practical Guide to Developing a WSP for a Small Supply; Practical Guidance for Risk Assessments; Establishing the Metals Problem: Risk Assessment, Sampling and Analysis; The Range of Possible Problems; Metal Solubility and Influencing Factors; Risk Assessment of Small Water Supply Systems; Sampling and Analysis; Consumer Awareness; Sources of Metals in Small Water Supplies; Origin of Contaminants; Contamination of Surface Waters; Contamination of Ground Water; Contamination from Treatment Processes; Contamination in Distribution Pipework; Contamination from Plumbing Fittings; Water Treatment Processes Available for Use on Small Water Systems; Process Selection; Types of Treatment; Practical Considerations of Treatment for Metals in Small Water Supplies; Iron; Manganese; Conditioning of Water to Prevent Dissolution of Plumbing Materials or Post-treatment Contamination; Treatment is Only Part of the Story; Indications and Effects of Post-treatment Metal Contamination in Small Water Supplies; Establishing the Source of the Problem; Factors Controlling the Corrosion of Metals into Small Water Supplies; The Conditioning of Water to Minimise Corrosion; Manual of Individual Metals in Small Water Supplies, Aluminium, Antimony, Arsenic, Barium, Beryllium, Boron, Cadmium, Chromium, Cobalt, Copper, Iron, Lead, Manganese, Mercury, Nickel, Selenium, Tin, Tungsten, Uranium, Vanadium, Zinc; Case Studies; Arsenic removal in Small Supplies in Italy; A New Borehole Supply with Iron Removal for a Single Property in England, UK; Metals in Small Water Supplies in Areas of Water Scarcity in African Regions; Unexplained Lead Contamination of a Small Water Supply in Northern Scotland EDITORS Matt Bower, Drinking Water Quality Regulator for Scotland, UK Colin Hayes, Swansea University, UK