Standards for Recreational Water Quality
November 2007

Bathing water has been recognised as carrying potential risks for decades. These risks, other than physical risks such as drowning, mostly arise as a consequence of the pollution of recreational water with micro-organisms that are present in faeces. Although there have been microbiological standards for recreational waters for many years in both North America and Europe, these have not been soundly based and they lacked epidemiological evidence that could support the argument that they were health-evidence-based. In order to improve this situation, epidemiological studies were carried out in the UK to quantify the potential health effects of bathing in recreational waters. These studies provide a scientific basis for developing standards based on practical measurements of contamination and the defined health risks which, mostly, relate to health outcomes with low levels of severity. The World Health Organization (WHO) has recognised that more information is needed from both fresh waters and from non-temperate conditions. However, the WHO has utilised the UK information to develop Guidelines for Safe Recreational Water Environments which were published in 2003. The approach used in those Guidelines offers a means of deriving standards that seek to limit health risks to clearly defined and acceptably low levels.

This approach has been the primary basis for the development of a new Bathing Water Directive for Europe. The new microbiological criteria for marine waters outlined in the 2006 Bathing Water Directive are, in part, based on the WHO criteria, but the derivation of the freshwater standards in the Directive is, at least partly, based on a German replication of the UK epidemiological research protocol.

Real time management of risk, through prediction of bathing water quality, has been suggested by the WHO in the 2003 Guidelines and is accommodated in the new Bathing Water Directive. Prototype systems, using electronic signs, are deployed in Scotland and this approach offers considerable scope particularly where microbiological pollution is episodically associated with rainfall causing runoff from livestock farming areas.

There is a review of the 2006 Bathing Water Directive criteria scheduled for 2008 and this may offer an opportunity to accommodate new scientific information from European Union (EU) studies coordinated by one of the authors of this report, from recently completed work and work underway, and to reconsider any inconsistencies identified.

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