Recreational water: natural and artificial bathing sites

In France, bathing is the most common water-based recreational activity. The two main types of areas for bathing and related activities are 1) public swimming pools, in which the water is treated in order to disinfect it and to provide it with disinfectant properties so as to ensure its compliance with microbiologic standards, and 2) natural and artificial bathing sites which sometimes benefit from specific improvements for the general public, but whose water is not treated. ANSES assesses the potential health risks associated with these two types of bathing areas. Read more about the Agency’s work on natural and artificial bathing sites here.

Bathing is the most popular recreational activity. It is not however free of risks such as drowning and various traumatic injuries but also chemical or biological risks due to the poor quality of bathing water or the surrounding environment.

The quality of bathing water is governed by the European Directive 2006/7/EC [1], transposed into French law in the Public Health Code in September 2008. It aims to improve the way the quality of bathing water is managed by 2015 while at the same time raising the awareness of the public. This regulation does not apply to the following classes of bathing area:

  • swimming pools or spa pools;
  • confined waters which are subject to treatment or used for therapeutic purposes;
  • artificially confined waters separated from surface water and groundwater.

Natural bathing sites may be contaminated by more or less purified grey water from collective or individual sewage plants, by run-off water or by point or temporary sources of pollution such as contamination by domestic or wild animals. The efficacy of natural purification which consists in filtering by plants and soil in particular, varies from one site to another.

The pollution risk is mostly microbiological, in other words related to the presence of pathogenic microorganisms in the water. These organisms, such as bacteria and viruses, following ingestion by humans or direct contact with their skin and mucous membranes, are likely to cause disorders (gastroenteritis, respiratory or skin ailments).

Through the season, water samples are taken at each bathing site at least twice a month. The results of these microbiological measurements are compared to the quality limits laid down by Directive 2006/7/EC. Physico-chemical quality markers are also measured. At the end of the season, départemental (county) reports are drawn up, following which the French Directorate General for Health (Ministry of Health) issues a national review and sends it to the European Commission. The results are communicated to the general public before the beginning of the next year’s bathing season. 

Artificial bathing sites

The Agency published a report by a group of experts in July 2009 following their assessment of health risks related to bathing in artificially confined waters that are not subject to the regulations in force. This report was in response to a formal request from the Ministries for Health, Ecology and Sustainable Development. Special attention was paid during the study to facilities that are marketed under the name of "biological or ecological swimming pools" whose number has increased significantly over the last 10 years.

The expert group classified existing artificially confined bathing waters on the basis of the three following criteria: nature of the body of water, quality of the hydraulic management and whether or not the water was treated. On this basis the experts suggested that’ artificial bathing be defined as: "bathing in diverted and confined water, treated or otherwise, but neither disinfected nor disinfecting".  This definition covers a wide range of very varied bathing areas such as lakes, sea pools, artificial ponds, water holes, diverted rivers, gravel pits, etc.

The Agency emphasises that the classifications "biological swimming pool" or "ecological swimming pool" are not correct since they do not correspond to swimming pools in the sense that mandatory regulations require that public swimming pools maintain "disinfected and disinfecting" water. The Agency recommended using the classification "bathing water treated by biological filtering".

The expert group identified a number of health risks, in particular:

  • pathogenic microorganisms introduced by bathers, which might contaminate other bathers and be responsible for most of the outbreaks declared for recreational waters;
  • toxins from micro-algae and cyanobacteria, whose proliferation is amplified in this type of water by particularly favourable conditions;
  • microorganisms and chemical pollution from the environment, via the water used for filling the bathing area, run-off of polluted water, intrusion of animals, etc.

The routes of exposure of bathers to the hazards mentioned above are ingestion, inhaling of water and contact with skin or mucous membranes.

All populations likely to use artificial confined waters may be affected by such exposure and in particular certain vulnerable populations such as children, pregnant women, the elderly and other people vulnerable to infections, as well as the professionals who work regularly at artificially confined bathing sites.

While the level of risk varies according to the efficacy of the hydraulic system and treatment of water in the facility, the risk of microbiological contamination appears, however, to be the predominant one, no matter what the type of artificially confined waters. The risk level will be directly proportional to the number of bathers and inversely proportional to the level of hygiene (i.e. the poorer the hygiene, the higher the risk).

The Agency underlined in this report the need to supervise and then monitor the development of artificially confined waters, by introducing specific procedures for managing health risks, including: 

  • the monitoring of specific microbiological parameters; 
  • the enforcement of strict hygiene measures and limiting the number of bathers per confined bathing area;
  • drawing up a profile of vulnerability to bathing and enforcing renewal of bathing water at prescribed intervals;
  • compliance with minimum technical specifications for operating such waters;
  • making marketing authorisation conditional on compliance with an approved list of treatment systems or processes;
  • implementing a system for managing non-compliant situations;
  • implementing a provisional management system pending specific regulations.

[1] Directive 2006/7/EC of the European Parliament and Council of 15 February 2006 concerning the management of bathing water quality and repealing Directive 76/160/EEC.