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Guidelines on Recreational Water Quality: Volume 1 Coastal and Fresh Waters [Internet]. Geneva: World Health Organization; 2021.
The World Health Organization (WHO) Guidelines on recreational water quality: volume 1 – coastal and fresh waters aims to protect public health by ensuring that the quality of recreational waters is safely managed. These guidelines update substantial content from the 2003 WHO Guidelines for safe recreational water environments: volume 1 – coastal and fresh waters and its 2009 addendum.
emphasis on preventive risk management through recreational water safety plans (RWSPs) at the centre of a water safety framework (Fig. 1.1); and
an exclusive focus on water quality, meaning that hazards that are not related to water quality (drowning; exposure to sun, heat and cold; and dangerous aquatic organisms) are outside the scope of this guideline. References to relevant guidance, including other WHO guidelines, on these topics have been added.
Use of coastal and freshwater recreational water environments has significant benefits for health and well-being, including rest, relaxation, exercise, cultural and religious practices, and aesthetic pleasure (Crouse et al., 2018; White et al., 2020). It also brings substantial local, regional and national economic benefits from tourism. However, recreational water environments contain potential hazards, which must be weighed against the benefits.
The benefits of recreational water use have increased competition for use of coastal waters and beach areas, leading to the need for clear regulations and codes of conduct. Management of recreational waters must carefully balance possible hazards against the benefits.
Recreational water sites are ecosystems that support a range of aquatic organisms, including fish and shellfish, insects and birds. Some of these organisms can be a nuisance or cause injury (e.g. jellyfish) or other health hazards (e.g. bird excreta, dangerous aquatic animals) to humans. Protecting human health may need to be balanced against environmental protection targets. Application of these guidelines therefore needs to consider targets and measures for the protection of coastal and aquatic ecosystems.
describe the current state of knowledge about the possible adverse health impacts of recreational use of coastal and freshwater environments; and
provide recommendations for setting national health-based targets, conducting risk assessments, and putting in place management approaches to identify, monitor and control these hazards, and associated public health surveillance and communication.
To apply the guidelines to local conditions, the social, cultural, environmental and economic characteristics of the country and recreational water site should be considered, as well as the activities undertaken, routes of exposure, and the nature and severity of hazards. Because these factors differ between sites, local, national and international standard-setting bodies may develop standards that differ between and within regions.
Recognizing the diversity of recreational water environments and users, these guidelines emphasize a flexible, proactive risk management approach that can be adapted to local hazards, conditions and priorities. This version has also been streamlined to focus more directly on hazards associated with (and near) water.
These guidelines focus on water quality management for public health protection for coastal and fresh water. Other WHO guidelines address treatment of swimming pools and spas, and recreational water hazards such as drowning; exposure to sun, heat and cold; and dangerous aquatic organisms. Resources for hazards that are not addressed in the guidelines are listed in Table 1.1.
References for hazards indirectly related to coastal and fresh water quality for recreational water users.
In these guidelines, coastal and freshwater recreational water environments are defined as any coastal, estuarine or freshwater area where any type of recreational use of the water is made by a significant number of users. Sporadic yet significant recreational use may also occur in water bodies not usually considered recreational sites; for example, sporting events may occur in rivers or even canals (Russo et al., 2020). Management of these types of events can still be governed and informed through the RWSP framework (Chapter 2).
Many different types of recreational, athletic and leisure activities occur in recreational water environments. These include both activities that involve water contact and activities that take place in the sand or near the water’s edge. These guidelines apply to all types of use entailing direct water contact, inhalation of sea spray and beach use.
Competition for suitable waters and the popularity of recreation may create conflicts between activities. For example, recreational use of drinking-water reservoirs can result in contamination of drinking-water sources by faeces, litter, oil and fuel. Dog walking and horse riding on beaches can result in faecal contamination of the beach, and potential transmission of zoonotic pathogens (e.g. Toxocara roundworms in dog faeces, dermatophytes in dog and horse hair) from the animals. Water resources management for hydropower and dams may prohibit recreational uses or lead to hazards associated with seasonal pollution due to the management of sediments. These conflicts can be resolved by supervision, regulation, codes of good practice and voluntary agreements. Approaches to developing control measures and management approaches for these types of conflicts can be designed as part of an RWSP (Chapter 2).
Users of coastal and freshwater recreational water environments include local residents; seasonal or sporadic users, such as tourists; and specialist sporting users, including competitive swimmers, surfers, anglers, canoeists, boaters and scuba divers.
The water quality guideline values recommended are for the general population. Hazards for particularly susceptible individuals and groups are also discussed.
Users can differ in their susceptibility to potential hazards. Children, for example, may be at greater risk because of their general reluctance to observe formal rules to ensure safety and hygiene. They are also likely to play for longer in recreational waters and are more likely to intentionally or accidentally swallow water (Schets, Schijven & de Roda Husman, 2011; DeFlorio-Barker et al., 2018). The elderly and people with disabilities may have lower strength, agility and stamina, which might limit their ability to recover from problems encountered in recreational water environments. Older and immunocompromised individuals may also be more susceptible to pathogenic organisms and therefore at higher risk of adverse health effects from microbial contamination of water. On the other hand, the elderly are likely to swallow less water during swimming, and may be more likely to heed rules and posted warnings about water quality and adverse conditions. Immunocompromised individuals should seek medical advice on their individual ability to tolerate exposure to surface recreational waters.
Traumatic events such as near drowning, when large volumes of water are aspirated, can also increase susceptibility to water quality hazards and result in rare adverse health outcomes such as severe pneumonia (Ender & Dolan, 1997). Extensive exposure to recreational waters by more susceptible populations should be considered in the management of recreational waters and as part of an RWSP.
Routes of exposure to infectious and toxic agents in water depend on the degree of water contact (Russo et al., 2020). The degrees of water contact encountered in coastal and freshwater recreational environments may be classified as follows.
No contact – recreational activity in which there is normally no contact with water or where water is secondary to enjoyment of the activity (such as sunbathing on a beach with exposure to beach sand and inhalation of sea spray; refer to Chapter 7).
Incidental contact – recreational activity in which only the limbs are regularly wetted and greater contact (including swallowing water) is unusual (e.g. boating, fishing, wading).
Whole-body contact – recreational activity in which the whole body or the face and trunk are frequently immersed, or the face is frequently wetted by spray, and where it is likely that some water will be swallowed (e.g. swimming, diving, surfing, sailboarding, kiteboarding, whitewater canoeing). Inadvertent immersion, through being swept into the water by a wave or slipping, would also result in whole-body contact.
These categories do not necessarily capture exposure to all potential hazards in the recreational water environment. For example, even no-contact activities can result in inhalation of sea spray containing algal toxins and exposure to potential hazards associated with sand.
Generally, exposure of skin and mucous membranes during recreational water activities is the most common route of exposure to hazards. The probability of ingestion of water is greater for whole-body contact activities. Inhalation can be important where there is a significant amount of spray, such as in waterskiing and jet-skiing. The skill of the individual in water recreation is also important in determining the extent of involuntary exposure, particularly water ingestion. Children ingest more water than adults during recreation, as a result of more vigorous activity and longer time spent in the water. Studies have also suggested that males tend to ingest more water during recreational swimming than females (Schets, Schijven & de Roda Husman, 2011; Dufour et al., 2017; DeFlorio-Barker et al., 2018).
These guidelines inform the development of regional and national approaches to manage recreational water quality and reduce health risks, based on a water safety framework (Fig. 1.1) to support setting of national health-based targets for water quality and public health surveillance (Chapter 2).
These guidelines place preventive risk management through RWSPs at the centre of the water safety framework in accordance with the harmonized Stockholm framework for risk assessment and management adopted for WHO guidelines on water and sanitation (Bartram, Fewtrell & Stenström, 2001). This leads to a comprehensive and proactive approach for local decision-making to assure water safety based on the severity and frequency of health risks. RWSPs emphasize common sense and practical preventive measures, and reduce reliance on water quality testing. Detailed guidance on development of RWSPs is provided in Chapter 3, and supporting technical information for each type of hazard is in Chapters 4–9.
A risk management approach can often lead to the adoption of standards that can be measured, implemented and enforced – for example, dealing with water quality, dissemination of information, education of children and adults, and the obligation to prepare and disseminate comparative studies of the safety of locations for recreational water use. In developing strategies to protect public health, competent government authorities should consider the general education of both adults and children, and the efforts and initiatives of nongovernmental organizations (NGOs) and industry operators in this area.
Clearly, a broad-based policy approach will be required that may include legislation, positive and negative incentives to alter behaviour, and monitoring of conditions. Such an approach will require intersectoral coordination and cooperation at national and local levels. Successful implementation will require development of suitable skills and expertise, and elaboration of a coherent policy and legislative framework.
Outline of the guidelines according to a recreational water safety framework.
These guidelines are primarily targeted at entities with responsibility for ensuring recreational water safety at several levels.
National and local agencies working in recreational water use – such as health, environmental and natural resource management bodies – have a responsibility to promote and ensure a safe environment.
Owners or service providers of recreational water areas may have a legal obligation to exercise due diligence relating to the safety of water or beaches.
NGOs and special interest groups with an important role to play in advocacy, communication and education; and
recreational water users seeking information in addition to readily available public communications advising of health risks associated with recreational water quality.
Mutually supportive actions are needed at local, national and regional levels to reduce risks encountered during recreational water use.
Many interdisciplinary experts and stakeholders are involved in the assessment, use and protection of recreational waters. If not already established, clear roles and responsibilities should be defined, and stakeholders’ efforts should be harnessed through an integrated planning framework. Fig. 1.2 illustrates the variety of stakeholders, and their roles in assessing and using recreational waters, and taking remedial action to limit health hazards.
Stakeholders in recreational water environments.
Agencies responsible for public health and/or environmental regulation will often take a leading and coordinating role in the application of recreational water guidelines. The coordinating authority should ensure the active participation of the other key stakeholders shown in Fig. 1.2. A wide variety of legislation and other regulation may contribute to ensuring and improving the safety of the recreational water environment. The potential actors and functions involved in improving safety are outlined in Table 1.2.
Examples of actors and functions for management of recreational water quality.
Antimicrobial resistance is an increasingly serious threat to global public health. Infections with bacteria and fungi that express antimicrobial resistance genes can be difficult or even impossible to treat. Antimicrobial resistance genes can transfer rapidly among bacteria and their bacteriophages in aquatic environments. Antimicrobial agents, detergents, disinfectants and residues from industrial processes may be present in recreational waters, leading to evolution and spread of resistance. Major sources of antimicrobial-resistant microorganisms include wastewater and sludges from municipal treatment plants, hospitals, agricultural runoff, and pharmaceutical manufacturing sites. Antibiotic-resistant strains of heterotrophic bacteria and of Enterococcus and Escherichia coli – bacteria that indicate faecal contamination – have been identified in recreational waters and beach sands (Huijbers et al., 2015; Leonard et al., 2015; Jorgenson et al., 2017). Surfers, who are frequent water users, have been found to be more than 3 times as likely as non-swimmers to carry resistant E. coli in their digestive systems (Leonard et al., 2018a).
The potential health impacts associated with antimicrobial-resistant organisms in recreational waters and beach sands are currently not well understood, and more research is needed to provide a better understanding of these hazards (Sanseverino et al., 2018).
The increasing impact of global climate change on recreational water environments and water quality is not well understood. However, climate change is expected to increase the frequency of severe weather events (e.g. extreme precipitation, floods, hurricanes, droughts) and cause rising sea levels. These conditions can damage sewerage infrastructure and overwhelm wastewater treatment plants (typically sited close to sea level), resulting in treatment bypasses, particularly in combined sewer and stormwater systems. They can also flood on-site sanitation systems such as septic tanks and pit toilets. All of these events can cause discharges of inadequately treated human excreta into surface waters and nearby recreational areas. In some water bodies, extreme climate events could cause increased blooms of harmful algae (cyanobacteria) and other water-based pathogens during periods of low flow and warm weather (refer to Chapter 5). Major storm events could increase runoff of domestic, industrial and agricultural waste from non-point sources into surface waters (refer to Chapter 4). A warming climate, in combination with increased levels of nutrient runoff, may also make conditions in some areas more favourable for naturally occurring opportunistic waterborne pathogens (e.g. Vibrio species) (Weiskerger et al., 2019).
Effects of climate change may also lead to positive consequences for health. For example, limited evidence suggests that summer rainstorms, which can reduce water quality at northern European and Mediterranean beaches (Spain and the United Kingdom), will be less likely in the period to 2100 under climate change scenarios (Figueras et al., 2011), leading to improvements in water quality during the summer bathing season.
Climate change impacts on recreational water will certainly vary locally, depending on the hydrological characteristics of a water body, and potential local scenarios should be considered as part of an RWSP (refer to Chapter 3).
Microplastics are plastics less than 5 mm in diameter that are either manufactured for use in cosmetics, facial cleansers and abrasives, or formed as a result of degradation of larger plastic items. Microplastics can enter water sources through wastewater treatment plant discharges, landfill leachate and sewage sludge, as well as through physical and chemical degradation of plastic wastes and litter. Chemical risks from microplastics are discussed in Chapter 8. Aesthetic and nuisance aspects of macroplastic litter are discussed in Chapter 9.
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