Page 8: Guidelines for Canadian Recreational Water Quality – Third Edition
Part I: Management of Recreational Waters
Barriers are procedures or actions that collectively reduce the risk of human exposure to recreational water quality hazards. They can be physical actions, such as beach cleanup and grooming, or they can be processes or tools that improve the effectiveness of the recreational water management program, such as policies and legislation, guidelines and standards, and education and communication strategies.
Four major areas have been described from which barriers can be identified (WHO, 2003a): compliance monitoring; public awareness and communication; public health advice; and hazard control actions.
Monitoring is a broad concept and can serve many functions. It can be used to:
- determine whether water quality meets the Guidelines
- identify the impacts of water quality events;
- demonstrate long-term water quality trends;
- support EHSS findings or identify gaps;
- verify that barriers (e.g. notifications, corrective actions) are put in place;
- verify that these barriers are operating effectively.
Compliance monitoring is conducted to identify existing water quality hazards and to maintain a record of changes that may occur. Proper monitoring and reporting are essential for assessing and communicating information on the level of safety of recreational waters. Decisions regarding the areas to be monitored, choice of indicators and monitoring program design will be made by the appropriate regulatory and management authorities. The monitoring program should incorporate information derived from the EHSS, taking into account recommendations made regarding priority areas of concern. There should be a documented monitoring plan for all monitored beaches, providing, at a minimum, instructions on:
- the parameters to be analysed;
- the locations at which samples are to be collected; and
- the times and frequencies of sample collection.
Recreational waters should be routinely monitored for the presence of faecal contamination, using the following primary indicators of faecal contamination:
- Fresh water: E. coli;
- Marine water: Enterococci.
Guideline values have been established for the geometric mean and single-sample indicator concentrations for these parameters (see Table 1 [Guidelines for Canadian recreational water quality: summary table] and Section 4.0 [Recommended indicators of faecal contamination]).
Other organisms have also been described that may have potential value as indicators by providing supplemental information with respect to the faecal contamination of recreational waters. Such organisms may also be included as part of a recreational water monitoring program, provided they have been deemed appropriate by the responsible regulatory and management authorities.
Other water quality parameters related to the physical or aesthetic characteristics of a recreational water body and its surrounding environment have links to the health and safety of recreational water users and thus may be included in a monitoring program. Guideline values or aesthetic objectives have been specified for these parameters where they can be established (see Table 1 [Guidelines for Canadian recreational water quality: summary table] and Section 8.0 [Physical, aesthetic and chemical characteristics]).
Tests may also be carried out for specific water quality hazards when there is epidemiological or other evidence of their presence in water. Evidence may include:
- reports of a disease outbreak or illnesses of specific etiology;
- reports of a suspected illness of undetermined cause;
- reports of water-related injuries;
- levels of an indicator strongly suggesting the presence of a specific hazard;
- reports of a specific event such as a sewage or chemical spill; or
- the development of a cyanobacterial bloom.
Procedures may also be established for the monitoring of other barriers that may be utilized for recreational water management. Examples may include:
- public notification / warning signs posted;
- water quality hazard control actions implemented;
- health authorities notified; and
- policies, legislation, protocols and/or guidelines established and in place.
It is recognized that recreational water areas will each have unique characteristics and operational considerations. Decisions regarding the specific design of the recreational water monitoring program should be made by the appropriate authorities (e.g. local, regional, federal, provincial, territorial, as applicable). These should take into consideration the specific needs and conditions of the area, the types of users and recreational activities practised, and any relevant historical information.
Decisions regarding the frequency of water samples collected for microbiological analysis should be made by the appropriate local or regional authority. Guidance is provided on some of the factors to be considered when selecting sampling frequency. Published texts are available that can provide further information with respect to the design and implementation of recreational water monitoring programs (e.g., Bartram and Rees, 2000).
There are a number of factors that can influence the microbiological quality of a recreational water body at any given time. These can include the type and periodicity of contamination events (both point and non-point sources), the time of day, recent weather conditions, the number of users frequenting the swimming area and the physical characteristics of the area itself. The significant day-to-day (and within-day) variation in indicator organism densities observed for recreational waters has been well documented (Leecaster and Weisberg, 2001; Boehm et al., 2002; Whitman and Nevers, 2004; U.S. EPA, 2005a).
Results from the U.S. Environmental Protection Agency's (EPA) Environmental Monitoring for Public Access and Community Tracking (EMPACT) Project identified that it is the day-to-day variation that is the principal source of uncertainty when attempting to develop an estimate of the water quality for a recreational water area over a given period (U.S. EPA, 2005a). Correlations were shown to exist only relative to indicator levels measured on the very next day. Indicator levels demonstrated only a negligible correlation with those measured more than 2 days later.
More frequent monitoring (daily as opposed to weekly sampling; weekly as opposed to monthly sampling) will have several advantages. As a result of the significant day-to-day variation in faecal indicator counts that can be observed, even daily monitoring will not necessarily improve the ability of the current day's microbiological results to predict the next day's water quality. However, the additional information provided by increasing the number of samples will allow the responsible authorities to more easily observe water quality trends and to make more informed decisions regarding the area's overall suitability for recreation. Moreover, it will enable authorities to more quickly detect persistent water quality problems that may occur.
The Guidelines advocate the use of both a maximum limit for the geometric mean faecal indicator concentration and a single-sample maximum limit. The use of dual limits allows recreational water operators to better evaluate the water quality both in the short term and over the duration of the swimming season. The single-sample limit will alert management to any immediate water quality issues, whereas the geometric mean limit will alert management to chronic contamination problems. This dual approach represents good monitoring practice as part of an overall commitment to a strategy of risk management for recreational waters.
In order to ensure that human health is adequately protected, waters regularly used for primary contact recreational activities should be monitored at a minimum frequency of once per week during the swimming season. A weekly monitoring strategy is useful to alert managers and responsible authorities to more persistent contamination problems that may have developed and allows them to make the necessary decisions within a reasonable time frame. Weekly surveillance is consistent with recommendations made by the U.S. EPA in its 2002 Implementation Guidance for Ambient Water Quality Criteria for Bacteria.
When sampling, consideration should also be given to the collection of samples for the purpose of characterizing event-driven episodes of pollution that may affect recreational waters--for example, immediately following periods of heavy rainfall or at times of greatest swimmer activity.
In areas where high swimmer densities are expected, increased monitoring is recommended. In such situations, the number of samples may be increased to permit the calculation of a weekly or even daily geometric mean (based on a minimum of five samples), if so desired.
Similarly, certain circumstances may permit a reduction in the recommended sampling frequency. These may include the existence of beaches in remote locations or in areas where primary contact recreational activities are not a regular occurrence or beaches that have historically demonstrated good water quality. Once an understanding of water quality behaviour at a site has been achieved through relatively intensive monitoring and the use of an Environmental Health and Safety Survey, a reduction in sampling frequency may be justifiable and can help ease the burden of monitoring (Bartram and Rees, 2000; WHO, 2003a). Thus, if it can be determined that a recreational water area is of consistently good microbiological quality, does not have any obvious sources of faecal contamination and is not considered to present a significant risk to the health and safety of its users, monitoring may be reduced to a frequency sufficient to verify that the conditions have not deteriorated.
It may also be good to reduce monitoring frequencies for recreational water areas that consistently demonstrate poor water quality results, but only where appropriate management actions are taken to discourage recreational use, and provided that the risks are clearly communicated to the public.
Decisions regarding the most appropriate location and depth of water samples collected for microbiological analysis should be made by the appropriate local or regional authority. Guidance is provided below on some of the factors to be considered when selecting sampling locations and depths. Published texts are available that can provide further information with respect to the design and implementation of recreational water monitoring programs (e.g., Bartram and Rees, 2000)
Most bodies of water used for recreational purposes are not completely homogeneous with respect to their microbiological properties. In recreational water evaluations, the purpose of sampling is to obtain aliquots that are as representative as possible of microbiological quality of the area. A single water sample provides a quantitative estimate of the indicator bacteria present at a particular site and time. Whitman and Nevers (2004) observed that there can be significant variation between samples collected at multiple points along the beach, as well as among samples collected within close proximity to each other at nearly the same time. As the total number of samples increases, the more representative the data will be of the overall water quality.
Sites should be chosen to be representative of the water quality encountered throughout the entire swimming area. Consideration should be given to specific conditions that may influence the levels and distribution of indicator organisms and pathogens. The sampling sites should include points of greatest swimmer activity, as well as peripheral points subject to external faecal pollution. Stormwater, sewage or river outlets can give certain sections of a body of water microbiological qualities that are very different from those of the water body at large. The degree of heterogeneity can also be affected by rainfall, wind direction and velocity, currents and tides, or the presence of physical barriers, such as sandbars, natural or artificial wave breaks and piers.
The depth at which samples are collected can have a significant effect on the resulting estimates of water quality (for the purposes of these Guidelines, 'depth' refers to the vertical distance in the water extending from the bottom of the water to the surface). Where the water is very shallow, disturbances of the foreshore sand and sediment caused by wave swash and swimmer activity can result in the resuspension of microorganisms. Where the water is deeper, this effect has lesser influence on water quality measurements. In contrast, deeper waters are relatively more exposed to offshore faecal contamination sources than shallower waters (U.S. EPA, 2005a).
Adult chest depth (approximately 1.2-1.5 m) has historically been the most common sampling depth. Traditionally this has been considered to represent the depth of greatest swimmer activity and the location nearest to the point of head immersion, which would be indicative of the risk associated with accidentally swallowing water. Published epidemiological studies have typically found that only samples collected at this depth show evidence of a mathematical relationship between indicator organism density and swimmer illness.
Sampling at shallower depths (ankle or knee depth--approximately 0.15-0.5 m) may be more representative of water quality encountered by young children playing at the water's edge. It is expected that more frequent swimming advisories would be issued if this monitoring approach were used. Sand and sediment disturbances can result in increased microbiological numbers in shallower waters. Currently there is insufficient evidence to determine whether the expected increase in the number of swimming advisories at this monitoring depth would result in a proportionate reduction in the number of swimmer illnesses.
Another strategy for monitoring that has been proposed involves the attempt to strike a balance between the depth at which the majority of the health effects have been proven and the depth at which microbiological counts are thought to be the highest (U.S. EPA, 2005a). According to the recommendations outlined in the U.S. EPA's EMPACT report (U.S. EPA, 2005a), sampling in water of knee to waist depth may offer a reasonable, but still conservative, approach to monitoring.
Alternatively, another approach would be for authorities to sample at multiple depths--for example, at ankle to knee depth, as well as at waist to chest depth. Such a design could be used to produce separate estimates of the water quality in both shallow waters and waters of swimming depth. However, when comparing the results of water samples between shallow and deeper waters, samples collected at a specific depth should be analysed as a singular group in order to improve the precision of the data.
The sample depth (or depths) selected for an individual beach should be determined by the local or regional authority in order to obtain the best information for their particular recreational water area.
Composite sampling
The use of composite sampling techniques presents a possible means for increasing the area covered under a beach monitoring program, while potentially minimizing the costs associated with analysis. Composite sampling involves the collection of multiple samples from across a stretch of beach, combining them into one large composite, and then analysing a subsample of the resulting mixture.
There are obstacles to be overcome with the use of this technique. Increased sampling is required initially to validate whether composite sampling will be feasible at a given area. As well the area must be characterized to identify hot spots (sampling points having continuously poor water quality) that can disrupt the analysis. Some statistical knowledge is also required to analyse the data. Nevertheless, preliminary investigations have suggested that, if properly conducted, composite sampling can be used in making water quality decisions with a comparable degree of accuracy to that achieved by analysing the samples individually and averaging the results (Kinzelman et al., 2006). Further information on composite sampling can be found in Appendix C (Composite sampling for faecal contamination).
Predictive water quality models
An emerging area of research has been the development of predictive models that are able to make same-day predictions about the microbiological quality of the water. Researchers have developed and validated models for specific beaches to make predictions of water E. coli levels using data from various water- and weather-related parameters (e.g., rainfall, wave height, wind direction, turbidity, previous day's faecal indicator counts). There are a few models currently used in beach monitoring programs in the United States:
- SwimCast, in use at several Lake Michigan beaches in Lake County, Michigan uses air and water temperature, wind speed and direction, precipitation, relative humidity, wave height, lake stage, sunlight and other water quality parameters to predict whether current E. coli levels are suitable for swimming (Olyphant and Pfister, 2005; Lake County Health Department, 2010).
- Project S.A.F.E. (Swimming Advisory Forecast Estimate) in use at five Lake Michigan beaches in northern Indiana uses wind direction, gauge height of the nearby Burns Ditch, rainfall in the previous 48 hours and lake conditions such as chlorophyll and turbidity to make predictions about relative E. coli levels and swimmability (Whitman, 2005; U.S. Geological Survey, 2007).
- Nowcasting in use at Huntington and Edgewater beaches on Lake Erie in Ohio makes use of log10 turbidity data, wave height and radar rainfall from grids surrounding the respective beach areas during the previous 24 or 48 hours to estimate if E. coli levels are Good for swimming at these beaches (Francy, 2007).
Evidence generated to date suggests that a properly developed model can achieve a degree of accuracy comparable to that achieved by traditional approaches that use the previous day's indicator concentrations.
There are a number of challenges associated with model development. A significant level of technical expertise is required to develop the models and to analyse the data, and models may not work in all areas. Nevertheless, they do present a possible means for forecasting the quality of the water, thereby improving the timeliness of decisions of whether to open or close a beach. Beach operators, service providers or responsible authorities looking for an additional tool with which to potentially improve the timeliness of their water quality decisions may wish to investigate this approach.
In order to participate in safe, enjoyable recreational water activities, the public requires access to information on the quality of the area and its facilities, as well as notification of any existing water quality hazards. Beach operators, service providers and responsible authorities have a responsibility to inform and educate the public and provide adequate warnings about any hazards relevant to their recreational water areas.
Efforts to improve the public's awareness and understanding of water quality can have numerous benefits (Bartram and Rees, 2000; Pendleton et al., 2001). Communication tools can be used to:
- reduce the potential risk of swimmer illness or injury;
- improve the quality of the water;
- correct public misconceptions regarding water quality;
- improve public confidence; and
- increase beach attendance.
Posting of information at recreational water areas
Information on the quality of the water should be communicated to the user through the use of posted signs. Signs should be used to warn users when the water is unsafe for recreational use as well as to communicate when the water is safe for use.
Signs should be posted in locations that are highly visible to the public. The information provided should be easily understood and not open to misinterpretation. Ideally, signs should be standardized to permit comparisons across different locations. Warnings should be timely and should be promptly removed once the issuing authority has determined that the risk no longer exists.
The information provided on warning signs should include, at a minimum:
- a statement identifying the health or safety risk;
- recommended actions to be taken;
- the name of the authority responsible for issuing the warning; and
- contact information for the issuing authority.
Similarly, during periods in which the area is considered suitable for use, corresponding signs should be posted that clearly communicate this information to the public. One important concept to communicate to beach users through education is that even in waters considered of good quality for swimming, there is always some probability that swimmers may experience some adverse health effects.
Examples of informative beach signs are provided in Appendix F.
There are two main situations under which a warning sign may be posted--following the issuing of a swimming advisory and following the issuing of a beach closure. Issuing a swimming advisory or a beach closure should be made by the Medical Officer of Health or other appropriate authority in accordance with the statutes existing in each province or territory. This decision should be based on a thorough assessment of the situation with information provided by recreational water monitoring, the EHSS and existing public health surveillance.
A swimming advisory can be issued if the responsible authority identifies that the water is not suitable for recreational use. Under this situation, users are advised to refrain from whole body contact with the water. Contact with the beach is usually permissible, and access to the facilities is generally not restricted. Examples of scenarios that may trigger jurisdictions to decide to issue a swimming advisory include:
- exceedance of the guideline values for the recommended indicators of faecal contamination;
- exceedance of the guideline values for toxic cyanobacteria and their toxins, or in the event of the development of a cyanobacterial bloom;
- existence of evidence of the risk of swimmer's itch for recreational water users; and
- after periods of significant rainfall, which could trigger an advisory as a pre-emptive action.
A beach closure can be issued if the responsible authority identifies that a beach or body of water poses a serious risk to the health and safety of recreational water users, and that it is further necessary to restrict individuals from coming in contact with the area. Under a closure, the area is considered closed to all recreational activity. Users are advised to avoid contact with the beach and recreational water area, and access to the facilities may be restricted. Examples of situations in which jurisdictions may determine it necessary to warrant the issuing of a beach closure include:
- suspicion that the area is responsible for a waterborne disease outbreak;
- a sewage or chemical spill that is expected to affect the recreational water area;
- other conditions such that the area is judged to pose a significant risk to public health (e.g., persistently poor water quality); and
- detection of a cyanobacterial bloom.
Appropriate signs may also be posted at waters that have been deemed suitable for secondary contact activities (e.g., rowing, sailing, canoe touring, fishing), but not for primary contact uses (e.g., swimming, wading, windsurfing, waterskiing). In these instances, it may be necessary to expand the location of the signs beyond the beach area to improve their visibility. Suggested locations include relevant points of entry and launch areas.
The public can also do their part by: educating themselves on actions they can take to protect themselves and the beach; becoming aware of where the water quality monitoring results are posted; and, consulting this information before going to the beach.
Other tools for public education and communication
In addition to posted signs, other tools can be used for public education and the communication of information, including:
- printed materials (e.g., posters, information sheets, educational bulletins, pamphlets, brochures);
- media sources (e.g., local newspapers, television and radio announcements, Internet websites);
- participation in beach certification or award programs;
- educational events such as volunteer monitoring programs and beach cleanup days; and
- classification or grading systems for beaches.
Classification or grading systems for beaches have received interest as a tool to promote communication and understanding of water quality information. They are also thought to help encourage a sense of shared accountability and responsibility among the beach authorities and beach users. A number of jurisdictions and multinational organizations have adopted grading systems as part of their recreational water management recommendations (WHO, 2003a; MDDEP, 2004; NHMRC, 2008). Both the WHO and the Australian Guidelines (WHO, 2003a; NHMRC, 2008) make use of a grade-based format for faecal indicator density within their framework for assessing faecal pollution in recreational waters. These approaches use a microbiological assessment component along with a sanitary inspection categorization to produce a classification of an area's overall suitability for recreation. Under the Quebec framework for faecal pollution assessment (MDDEP, 2004), water quality grades are assigned to recreational waters based on average yearly faecal indicator monitoring results. This grade is used as a public communication tool and also dictates the sampling frequency requirements for the area.
There are advantages and disadvantages associated with the use of beach grading systems. Responsible authorities should be aware of the limitations of any system when investigating its use as a potential communication tool. For example, grading systems based on faecal indicator monitoring results provide information on only one aspect of recreational water safety. Moreover, the accuracy of any such grading system would be strongly affected by the limitations known to be associated with faecal indicator monitoring. Ideally, a successful beach grading system would involve criteria from a number of categories, capturing monitoring results, communication tools and water quality hazard control actions in place.
Consultation with public health authorities is another essential component of risk management. In the event of an incident (microbiological, chemical or physical) that represents a risk to public health or safety, health officials can play a key role by providing advice and determining what actions need to be taken. Local public health authorities should be promptly notified of any situation that threatens the health or safety of recreational water users. Similarly, as part of normal operations, local public health officials may be periodically consulted for information and advice on topics pertinent to safe recreational water use.
In assessing the risks associated with recreational water quality hazards, the local health authorities should, wherever possible, establish surveillance for swimmer illness or injuries. This can be established by consulting public health surveillance mechanisms currently in operation or by conducting specific investigations. Information sources include:
- federal, provincial/territorial or regional departments or agencies having surveillance programs or reporting systems;
- clinical reports from hospital emergency departments and local physicians;
- accident or incident reports held by recreational water area operators or service providers;
- formal epidemiological investigations; and
- other potential surveillance mechanisms (e.g., monitoring of over-the-counter medicine sales in pharmacies).
Procedures for the investigation of illness associated with recreational waters should adhere to the recommendations given in the second edition of Procedures to Investigate Waterborne Illness (International Association for Food Protection, 2002).
Hazard control actions are physical actions intended to reduce the impact of microbiological, chemical or physical water quality hazards on a particular recreational water site. A discussion on the numerous types of possible hazard control actions is outside the scope of this document. In addition, the types of hazard control actions required and their relative effectiveness will be specific to each beach and each situation. Authorities may wish to consult the following types of resources for information to help them address specific beach-related issues:
- Published texts: Texts are available which provide comprehensive discussion of larger topics like stormwater management, wastewater treatment and coastal water management.
- Searchable databases of journal articles: Keyword searches can direct the user to specific scientific studies, related articles, bibliographical citations and topic review papers.
- Proceedings from international conferences: Review of proceedings can identify accounts of actions evaluated in other communities, providing an indication of results and potential contacts; specific conferences include: Great Lakes Beach Association Conferences, and the U.S. EPA National Beach Conferences.
- Manuals or publications produced by stakeholder organizations (e.g., Griffiths, 1999).
Assessment may help identify smaller-scale actions that may provide good returns from a cost-benefit perspective. However, some issues may be more substantial in nature and thus may not be easily resolved without the application of more sophisticated control methods. Examples of small-scale control actions aimed at reducing faecal contamination can include beach cleanup or grooming procedures or installation of structures (fences, overhead wires) to discourage the presence of birds and other wildlife. Examples of larger-scale actions can include sewage treatment or storm drain waste retention. Any potential control action should be assessed from the perspectives of the effects on the health of the users and on the environment.
Water quality issues can cross over multiple boundaries (e.g., health, environment, agriculture, municipal infrastructure), and require cross-sectoral collaboration. Consultation with responsible authorities, other beach operators or service providers and recreational water quality professionals may help to identify actions that have proven to be successful in other communities.
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