Executive summary

Faecal indicator organism (FIO)

Intestinal enterococci in both marine water and fresh water^1,2

Guideline value

200/100 mL (upper 95th percentile)^3,4

System assessment and beach classification

• Classify beaches by combining water quality testing and sanitary surveys (refer to sections 4.1–4.3).

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  Undertake a sanitary survey to identify all sources and conditions leading to faecal pollution (refer to section 4.1.2).

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  Determine recreational water quality from an initial microbial water quality assessment (refer to section 4.2.1).

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  Combine results from the sanitary survey and the microbial water quality assessment to classify the recreational water environment as very good, good, fair, poor or very poor (refer to section 4.3).

• Undertake further assessment, and possibly on-site empirical investigations, if there is discrepancy between the results of the microbial water quality assessment and the sanitary survey.
• Consider upgrading the beach classification to a more favourable level if local management actions (e.g. advisories) are effective.

Operational and verification monitoring

• Undertake initial microbial water quality assessment to inform beach classification (as described above).
• When unacceptable levels of FIOs are detected and sewage is not the likely source, identify the faecal source(s) contributing FIOs (e.g. through sanitary surveys of the catchment or where resources permit microbial source tracking).
• Monitor the functioning of control measures using operational (microbial and nonmicrobial) parameters (e.g. warnings from release of poorly treated sewage or faecal sludge from a utility or service provider, rainfall that may affect runoff, changes in wind speed or direction, water temperature, water quality testing) and predictive modelling to allow timely warnings to water users.
• Conduct ongoing verification monitoring to check whether water quality is likely to be high enough to meet health-based targets (refer to Table 4.2 for recommended verification monitoring schedule).

Examples of management and communication

• Enforce compliance with regulations. For catchment pollution from human or nonhuman sources, identify major sources of pollution and develop a catchment-wide pollution abatement programme (refer to section 4.4).
• Manage pollution of recreational waters by human or animal wastes containing faecal bacteria or pathogens through system upgrades (e.g. tertiary treatment of human effluent for direct point-source pollution and/or appropriate disposal of human effluent through long outfalls to separate discharges from water users).
• Public health authorities should be engaged in defining water quality standards or appropriate triggers relevant to exceptional circumstances (e.g. sewer breaks, extreme floods and rainfall events with a recurrence interval of more than 5 years).
• Develop predictive models for real-time operational monitoring and public communications, where feasible (refer to section 4.2.3).
• Post advisory notices of likely adverse water quality if:

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  weather events, such as high rainfall, lead to elevation of FIOs in recreational waters;

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  a rare or extreme event causes gross pollution of the bathing water; or

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  sewage, septic tank effluent and/or faecal sludge discharges occur that are unrelated to weather events.

Indicators and guideline values

Freshwater and brackish water bodies⁵

Cyanobacterial biomass indicator values (thresholds in Fig. 5.1 alert level framework):

• Vigilance level – 1–4 mm³/L biovolume or 1–12 µg/L chlorophyll a (with dominance of cyanobacteria).
• Alert Level 1 – 4–8 mm³/L biovolume or 12–24 µg/L chlorophyll a (with dominance of cyanobacteria).
• Alert Level 2 – scum or transparency <0.5–1 m.

Note that clear water bodies with far lower plankton biomass may harbour toxic cyanobacteria growing on surfaces such as sediments and submerged plants as mats, which can detach and float in the water or be washed ashore.

Cyanotoxin guideline values (thresholds in Fig. 5.1. alert level framework):

• Microcystin GV_recreation – 24 µg/L (provisional).
• Cylindrospermopsin GV_recreation – 6 µg/L (provisional).
• Anatoxin-a GV_recreation – 60 µg/L (conservative health-based reference value due to lack of effects in chronic studies).
• Saxitoxin GV_recreation – 30 µg/L

System assessment

• Develop a surveillance strategy that gives priority to the highest-risk sites based on the likelihood of toxic blooms and patterns of recreational use (refer to Table 5.2).
• Develop an understanding of water body conditions (including under predicted local climate change scenarios), as the basis for assessing risks of bloom occurrence and thus of exposure during recreational activities (e.g. excluding fast-flowing rivers where blooms cannot form and lakewater aerosols).
• Compile an inventory of activities in the catchment causing nutrient loads that sup-port HABs.

Fresh water:

• Use total phosphorus concentrations above 20 µg/L and/or cyanobacterial occur-rence as a screening level for water bodies at risk of planktonic HABs, taking note of the possibility of HABs growing on surfaces in clear water bodies with lower total phosphorus concentrations.
• Choose parameters (e.g. biovolumes) that indicate potential levels of cyanotoxins, and define the levels that trigger specific actions.
• Interpret laboratory data in conjunction with visual information from site inspec-tion, observation of scums and water transparency, and qualitative microscopy.

Coastal and estuarine water:

• Assess the potential for bloom development based on nutrient input causing eu-trophication (i.e. nutrient enrichment that promotes blooms), water temperature and water flow dynamics (noting that most marine HABs primarily affect health through ingestion of contaminated seafood); adverse effects may occur from inha-lation of spray from marine water or scum containing algal species, or at tropical and subtropical beaches from skin contact with filamentous tropical cyanobacteria growing on surfaces causing severe skin lesions (Moorea, formerly called Lyngbya).

Operational and verification monitoring for fresh, coastal and estuarine waters

• For activities in the catchment causing nutrient-rich fluxes to water bodies used for recreation, work with relevant operators to develop methods to control and monitor nutrient release.
• Specify the aims of monitoring, and decide on the sampling sites, intensity of monitoring and analytical targets (refer to Table 5.4).
• Use long time series of data records on phytoplankton populations to improve understanding of the dynamics of HAB growth, predict the appearance of potentially toxic HABs, and allow recognition of new species in the area.
• Apply visual, biological, biochemical and physicochemical methods to determine the likelihood and presence of HABs and concentrations of cyanotoxins.
• Conduct water quality analysis based on visual examination (e.g. scum, coloured turbidity, biovolumes or chlorophyll a concentration, remote sensing) or toxin analysis in situations where health risks are likely (for fresh and brackish water, refer to Fig. 5.1 alert level framework).
• Mobilize citizen science for data collection, where feasible.
• Intensify monitoring activities when conditions favourable to HAB development are recognized.
• Document the occurrence of HABs and inform public health authorities when they occur.
• In the event of illness (including animal deaths) that is possibly associated with HABs, undertake verification monitoring. Establish communication lines for rapid water quality analyses of the recreational water body and toxin analysis to provide information for diagnosis and for immediate management actions.

Examples of management and communication

Fresh water and brackish water:

1. Implement an alert level framework (refer to Fig. 5.1).
2. Inform public health authorities when blooms occur. Lifeguards, where present, and beach managers can provide information on bloom occurrence.
3. Develop an incident response plan to ensure a rapid and coordinated reaction in the case of a heavy bloom or incident (e.g. death of pets or livestock, or human illness) caused by a bloom.
4. Ensure that users of recreational water bodies have sufficient information and are actively engaged in assessing whether it is safe to swim (e.g. through signs, social media and hotlines).
5. Reduce nutrient (often phosphorus) input from the catchment to the water body from human excreta from sewage and wastewater, fertilizers, manure and slurry spread on land, and wastewater from industries and manufacturing enterprises (refer to Fig. 5.4).
6. If HAB toxin concentrations or biomass volumes remain too high and blooms still occur, or if more immediate success is needed, consider implementing an internal measure that makes conditions less favourable for cyanobacteria, noting some may not be practical or may have adverse ecological effects (refer to Table 5.3).

Coastal and estuarine water:

• For planktonic HABs, implement points 2–4 above. Consider also developing a similar alert level framework.
• For tropical/subtropical beaches with filamentous cyanobacteria (Moorea, formerly called Lyngbya) growing on surfaces, removing detached filaments accumulating on beaches and providing information to site users (refer to point 4 above) are the only options known to be effective.

For health authorities and water managers:

• Develop outreach materials explaining causes of HABs, and options and responsibilities for controlling them.

For recreational water users:

• Inform the public and policy communities how to recognize HABs and avoid exposure – and who to notify in cases of concern.

For medical practitioners:

• Inform medical practitioners about the symptoms HAB toxins may cause, their often mild and self-limiting nature, the conditions under which severe illness needs to be considered, measures to take if exposure to HAB toxins may have been substantial, and the communication lines to use if an HAB is suspected as the cause of symptoms, to immediately trigger water sampling and analyses (which are crucial to confirm a diagnosis and to prevent further exposure).

Indicator

None (refer to “Operational and verification monitoring” below).

Guideline value

Not applicable – no dose–response relationship can be established for these organisms.

System assessment

Incorporate risk factors for the other microbial hazards of concern for the catchment within the RWSP system assessment by preparing an inventory of microbial hazards that have been observed or are likely to be present and incorporating risk factors likely to promote their proliferation.

Operational and verification monitoring

• For organisms whose prevalence is strongly dependent on environmental conditions, incorporate indirect operational monitoring of environmental conditions (e.g. temperature) into RWSPs.
• Undertake verification monitoring and surveillance of illness at a national level, to enable analysis of information on symptoms, severity, pre-existing conditions and the likely recreational source of infection.
• Regular pathogen monitoring is not recommended except under exceptional circumstances (and if site-specific guideline values are established) – for example, before and after a water sports event, or during heatwaves in locations with a history of Vibrio infections. Targeted screening can be used for investigative and research purposes.

Examples of management and communication

For health authorities and water managers:

• In catchments and bathing sites where severe infections (e.g. primary amoebic meningoencephalitis, severe leptospirosis) are suspected, incorporate pathogen-specific management and communication measures into the RWSP.
• Potential control measures include site management (e.g. control of vectors or macrophyton) and behaviour change approaches (e.g. hygiene measures for water users).
• Where non-native animal carriers play a role in disease transmission, manage the recreational site to control these animals.
• Where a site has been linked to infection or has conditions that are suitable for the causative organism, inform site users to allow them to make an informed decision.

For recreational water users:

• General precautions

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  Cover existing skin lesions with waterproof dressings before entering the water. If an injury is sustained while in the water or at the recreational site, wash the wound thoroughly with soap and water.

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  Remove wet swimwear; shower and towel dry after water exposure.

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  Remove contact lenses before bathing in warm fresh water.

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  For water sports, wear protective clothing where the risk of infection is high.

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  If an infection develops after recreational water exposure, seek medical advice.

• Specific precautions

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  Protect against swimmer’s itch by avoiding high-risk areas (shallow water with dense vegetation) and high-risk periods (early morning at some sites).

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  Reduce exposure to Naegleria fowleri by minimizing the amount of naturally warm fresh recreational water entering the nose (e.g. keeping the head above water, holding the nose shut, using a nose clip).

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  People with underlying medical conditions (especially hepatic disease or other chronic illness) should limit their exposure to brackish water or seawater.

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  Seek medical advice if planning to engage in recreational water activities in areas where human schistosomiasis and leptospirosis are endemic.

For medical practitioners:

• Pay attention to risk behaviours such as travel to endemic areas, adventure travel and extreme water sports.

Indicator

Intestinal enterococci in both marine water and fresh water (where justified by national or local risk assessment, and resource availability for monitoring and control measures).

Provisional guideline value

60 CFU/g^6,7

System assessment

Incorporate risk factors for pathogens of concern in beach sand into RWSP system assessment, paying particular attention to beaches that are vulnerable from a physical and geomorphological perspective (enclosed beaches with minimal wave action).

Operational and verification monitoring

• Undertake pathogen sampling and analysis (refer to section 7.2.3).
• Undertake operational monitoring of priority sources of sand pollution (e.g. dogs and birds on beaches).

Examples of management and communication

For health authorities and water managers:

• Limit access to the beach by dogs and feral animals, such as cats.
• Prepare management plans for birds.
• Provide properly designed solid waste disposal facilities.
• Provide toilet facilities, appropriate wastewater and sludge treatment, and stormwater drainage.
• Conduct beach grooming to eliminate visible solid waste (taking care to minimize impacts on sand ecology).
• Check the quality of source sand if beach sand renourishment is used to build artificial beaches or restore natural beaches.
• Apply additional strategies for beaches that are vulnerable from a physical and geomorphological perspective (enclosed beaches with minimal wave action).

For recreational water and beach users (in the absence of environmental measurements):

• Use a towel when sitting on the beach.
• Wear shoes to minimize cuts when walking on the beach.
• Protect open wounds from water and sand exposure.
• Beach clean-up workers may be encouraged to wear protective clothing, including gloves and possibly dust masks.
• Shower upon leaving the beach.

For public health authorities:

• Stay in contact with lifeguards for potential reports of on-site outbreaks.
• Proactively intervene by contacting medical centres – remind staff to be alert to possible beach-related outbreaks and ailments.

Indicator

None – except for specific chemicals where justified by national or local risk assessment, and resource availability for monitoring and control measures.

Guideline value

As a screening approach, investigate substances occurring in recreational water at a concentration 20 times higher than the guideline value in the WHO Guidelines for drinking-water quality.

Risk assessment

Incorporate assessment of chemical hazards in recreational waters into RWSPs, using information on potential sources of chemical hazards within the catchment, and the frequency, extent and likelihood of exposure.

Operational and verification monitoring

• Undertake operational monitoring for the highest-risk chemical discharges (e.g. discharge permit compliance, flow rate); monitor fencing and signage, if installed, to prevent access to water bodies (e.g. quarry lakes) that are permanently unsuitable for recreational use; monitor soil and groundwater downstream of contaminated sites.
• Use chemical analysis to support a quantitative risk assessment if contamination is present or suspected and there is significant exposure of users.

Examples of management and communication

For health authorities and water managers:

• Manage pollution events, and provide timely and effective information (e.g. issue media advice, communicate with community or resident groups, install warning signs) about recreational water environments affected by chemical hazards.

For recreational water users:

• Provide information about the nature of the contamination, potential health risks, activities to be avoided and planned remedial action.

Indicator

None (refer to “Operational and verification monitoring” below).

Guideline value

Not applicable.

System assessment

Incorporate aspects of aesthetics and nuisance into RWSP system assessment.

Operational and verification monitoring

Local authorities and/or citizen science can undertake periodic (e.g. daily, weekly) operational monitoring via visual inspection and data collection on priority aesthetic aspects of concern.

Examples of management and communication

For health authorities and water managers:

• Provide solid waste disposal facilities.
• Undertake beach grooming and litter clean-ups for beaches receiving litter or excessive macroalgae from offshore.
• Provide information to beach users on proper solid waste disposal, and avoiding nearshore nuisances such as jellyfish.
• Undertake insect control for sites with excessive mosquitoes, flies and other nuisance insects.
• Develop policies and management for non-native animals on the beach (e.g. discourage pets and feeding of birds, keep solid waste inaccessible). If dogs are permitted, put in place policies and procedures to minimize their impacts on the aesthetic quality of the beach.