Time series study of weather, water quality, and acute gastroenteritis at Water Safety Plan implementation sites in France and Spain

Bacterial accumulation dynamics in runoff from extreme precipitation

Extreme precipitation can significantly influence the water quality of surface waters. However, the total amount of bacteria carried by rainfall runoff is poorly understood. Here, thirty rainfall scenarios were simulated by artificial rainfall simulators, with designed rainfall intensity ranging from 19.3 to 250 mm/h. The instantaneous concentration ranges of R2A, nutrient agar (NA) culturable bacteria, and viable bacteria in runoff depended on the types of underlying surfaces. The instantaneous bacterial concentrations in runoff generated by forest lands, grasslands and bare soil were: R2A culturable bacteria = 104.5-6.3, 104.5-6.1, 104.0-5.3 colony-forming units (CFU)/mL, NA culturable bacteria = 104.0-6.0, 103.9-5.8, 103.2-4.9 CFU/mL, and viable bacteria = 106.4-8.0, 107.0-8.9, 106.4-7.6 cells/mL. Based on the measured bacterial instantaneous concentration in runoff, cumulative dynamic models were established, and the maximum amount of culturable bacteria and viable bacteria entering water sources were estimated to be 109.38-11.31 CFU/m2 and 1011.84-13.25 cells/m2, respectively. The model fitting and the bacterial accumulation dynamics were influenced by the rainfall types (p < 0.01). Surface runoff from the underlying surface of forest lands and grasslands had a high microbial risk that persisted even during the "Drought-to-Deluge Transition". Bacterial accumulation models provide valuable insight for predicting microbial risks in catchments during precipitation and can serve as theoretical support for further ensuring the safety of drinking water under the challenge of climate change.

Dual system of water safety plan auditing in Hungary: benefits and lessons learnt

A risk-based approach is recognised worldwide as the most reliable means for the provision of safe drinking water. Efficient implementation of the water safety plan (WSP) approach, recommended by the World Health Organization (WHO), is facilitated by an auditing framework. In Hungary, development of WSPs is a legal obligation for water suppliers. WSPs are subject to a two-stage regulatory audit, a consultative central technical audit and a formal local audit. In 2019, a survey was conducted in cooperation with WHO to evaluate audit experiences of over 1,200 WSPs. Recommendations from the central audit significantly improved coherence and compliance of WSPs, confirming the efficiency of the dual approach. The use of a WSP template provided by the national authority further increased consistency and reduced time and work demand of the audit. Both water suppliers and public health authorities indicated a need for further capacity building on WSP development and auditing. The main challenge for water suppliers is the identification and risk assessment of hazards associated with the water source and distribution within premises. The recast European Union drinking water regulation is expected to accelerate the uptake of WSP and strengthen linkages to water catchment management and water safety in buildings.

Water safety plans and risk assessment: A novel procedure applied to treated water turbidity and gastrointestinal diseases

Water Safety Plans (WSPs), as recommended by the World Health Organization (WHO), can help drinking water suppliers to identify potential hazards related to drinking water and enable improvements in public health outcomes. In this study we propose a procedure to evaluate the health risk related to turbidity in finished water by determining the cases of drinking water-related gastrointestinal diseases. The results of several epidemiological studies and three-year time series turbidity data, coming from three different drinking water treatment plants (WTPs) located in Tuscany (Italy), have been used to determine the relationship between drinking water turbidity and gastroenteritis incidence and to assess the health risk attributable to the turbidity of tap water. The turbidity variation occurring in the treated water during the monitored period showed an incremental risk compared to the baseline value from 9% to 27% in the three WTPs. Risk reduction due to each treatment step was also evaluated and it was found that a complete treatment train (clari-flocculation, sand filtration, activated carbon filtration and multi-step disinfection) reduces risk by over 600 times. Our approach is a useful tool for water suppliers to quantify health risks by considering time series data on turbidity at WTPs and to make decisions regarding risk management measures.

Including aspects of climate change into water safety planning: Literature review of global experience and case studies from Ethiopian urban supplies

In recent years, the water safety plan approach has been extended towards climate-resilient water safety planning. This happened in response to increasing insight into impacts of climate on drinking-water and required adaptation to anticipated climate change. Literature was reviewed for published guidance and case examples, documenting how to consider climate in water safety planning to support future uptake. Climate-resilient water safety plans were piloted within a project in the water supplies of Addis Ababa and Adama, Ethiopia. Case examples have been published in four of six WHO regions with a focus on urban supplies. Integration of climate aspects focused mostly on the steps of establishing the team, system description, hazard analysis and risk assessment, improvement planning and development of management procedures. While the traditional framework focuses on drinking-water quality, considering climate change augments aspects of water quantity. Therefore, other factors affecting water quantity such as population development and demand of other sectors need to be considered as well. Local climate information and tools should be employed as a significant success factor for future uptake. Such information should be incorporated as it becomes available, and may - depending on the setting - be incrementally integrated into existing water safety plans or used to develop new ones.

Faster and safer: Research priorities in water and health

The United Nations' Sustainable Development Goals initiated in 2016 reiterated the need for safe water and healthy lives across the globe. The tenth anniversary meeting of the International Water and Health Seminar in 2018 brought together experts, students, and practitioners, setting the stage for development of an inclusive and evidence-based research agenda on water and health. Data collection relied on a nominal group technique gathering perceived research priorities as well as underlying drivers and adaptation needs. Under a common driver of public health protection, primary research priorities included the socioeconomy of water, risk assessment and management, and improved monitoring methods and intelligence. Adaptations stemming from these drivers included translating existing knowledge to providing safe and timely services to support the diversity of human water needs. Our findings present a comprehensive agenda of topics at the forefront of water and health research. This information can frame and inform collective efforts of water and health researchers over the coming decades, contributing to improved water services, public health, and socioeconomic outcomes.

Assessing operational performance benefits of a Water Safety Plan implemented in Southwestern France

AIMS

The World Health Organization (WHO) has recommended Water Safety Plans (WSPs) since 2004 as a means to reduce drinking water contamination and risks to human health. These risk management programs have shown promise across several potential areas of evaluation, such as economic benefits and regulatory compliance. Since WSPs are largely carried out by people who interact with water treatment equipment and processes, operational performance indicators may be key to understanding the mechanisms behind desirable WSP impacts such as water quality and public health improvement.

METHOD

This study reports performance measures collected at a WSP implementation location in southwestern France over several years.

RESULTS

Quantitative assessment of performance measures supported qualitative reports from utility managers. Results indicate significantly reduced duration of low-chlorine events at one production facility and a significant decrease in customer complaints related to water quality, manifesting reported improvements in operational performance and the customer service culture.

CONCLUSION

The findings demonstrate some success stories and potential areas of future performance tracking. Cyclical iteration of the WSP can help to achieve continuous quality improvement. Successfully applied evaluation criteria such as the number of water quality complaints or alarm resolution time might be useful across other locations.