Guidelines for Canadian Recreational Water Quality

2. General Requirements for Recreational Water Quality

Waters used for recreational purposes should be sufficiently free from microbiological, physical, and chemical hazards to ensure that there is negligible risk to the health and safety of the user. The determination of the risk of disease or harm from microbiological, physical, or chemical hazards is based on a number of factors, including the following:

• environmental health assessments
• epidemiological evidence
• indicator organism limits
• presence of pathogens.

The decision to post a warning to users of recreational areas or to close an area for public use should be made by the Medical Health Officer or other appropriate authority in accordance with the statutes existing in each province. This decision will be based on an assessment of existing hazards using available information on the factors listed above.

2.1 Environmental Health Assessments

An annual environmental health assessment should be carried out prior to the bathing season on the watershed or the area from which water flows to a recreational area, as well as on the recreational area itself. This survey should identify all potential sources of contamination and physical hazards that could affect the recreational area. Appendix 1 provides a suggested checklist for the health inspector or other appropriate authority to use when making an assessment.

Attention should be paid to the following:

• the risk of inadequately treated sewage, fecal matter, or chemical substances entering the water, from either a discharge or a spill
• knowledge of all outfalls or drainage in the area that may contain sewage, including urban storm water and agricultural waste or runoff
• an inspection of the area for physical hazards
• an assessment of the seasonal variability of hazards, the density of bathers, the water temperature, the frequency of change or circulation of the water, changes in water depth, and the occurrence of algal blooms
• the fluctuation of water quality with rainfall (wet and dry conditions)
• a reporting mechanism to ensure that health authorities are informed of any malfunction or change to a municipal, private, or industrial waste treatment facility that might cause a deterioration of the water quality of a bathing area.

2.2 Epidemiological Evidence

The local health authorities responsible for making recommendations for a recreational area should, wherever possible, establish surveillance for bather illness or injuries. This can be established by comprehensive epidemiological studies or by formal and informal reporting from physicians and hospital emergency departments. This surveillance will be increased if there have been reports of suspected illness or injuries. The water quality may be considered impaired and appropriate recommendations made as a result of this surveil-lance. Procedures for the investigation of illness associated with recreational waters should adhere to the recommendations given in Procedures to Investigate Waterborne Illness (International Association of Milk, Food and Environmental Sanitarians, Inc. 1979).

2.3 Indicator Organism Limits

An indicator organism or organisms should be chosen by the local health authority in consultation with the laboratory microbiologists for each area. It is recommended that one of the following indicator organisms be used for routine monitoring of recreational water quality - enterococci, Escherichia coli, or fecal coliforms.

The choice of indicator organism and of enumeration procedures will be determined according to:

• whether the water is marine (salt), fresh, or estuarine (variable salinity)
• the presence of turbidity, which may interfere with microbiological methods
• any known correlation of illness with levels of indicator organisms
• the proportion of fecal coliforms in the area that are E. coli, if fecal coliforms are used as indicator organisms
• local experience of monitoring with a particular organism.

Later sections recommend the limits for each organism and the criteria to assist in the choice of that organism for routine monitoring. Guidelines for sampling and microbiological methods are also discussed.

The decision to carry out routine microbiological monitoring of a recreational area will be made by the local health authorities or other responsible agency, based on the usage of the area, the environmental health assessment, and epidemiological evidence.

2.4 Presence of Pathogens

Tests for pathogenic organisms may be carried out when there have been reports of illnesses of specific etiology, when there is suspected illness of undetermined cause, or when levels of an indicator organism demonstrate a continuous suspected hazard. The tests will help to determine the source of contamination (e.g., sewage pollution, agricultural or urban runoff, bather origin).

The local health authorities should take action when pathogenic organisms are identified in sufficient quantity or frequency to be considered a hazard. Such pathogenic organisms may be Aeromonas spp., Pseudomonas aeruginosa, Staphylococcus aureus, Shigella spp., Salmonella spp., Campylobacter spp., Giardia spp., human viruses, and toxic phytoplankton. An appropriate response should be based on the knowledge of the source of the organism and the probability of the hazard being temporary or continuous.