Delivering healthy water: building the science-policy interface to protect bathing water quality

The quality of UK bathing waters is assessed by enumerating bacteria known as faecal indicator organisms (FIOs) throughout the bathing season. Waters used to harvest shellfish are monitored for FIOs too. E. coli is a common FIO derived from the gut of warm blooded animals and is harmless, but its detection in environmental samples or shellfish flesh indicates the potential for the presence of disease causing microbes derived from faecal material. Their detection at designated bathing and shellfish harvesting waters at levels above standards specified within EU directives can lead to beach closures or shellfish stocks being classed as unfit for human consumption and can therefore have serious implications for local economies and social activity as well as human health.

From 2012 the number of UK beaches of poor microbiological status is set to rise because of the introduction of more stringent standards associated with the revised Bathing Waters Directive in Europe. Meeting these new standards and avoiding infraction (and therefore economic consequences) will be a challenge. However, parallel debates over the suitability of traditional versus novel quantification methods add an extra layer of complexity for regulators to grapple with. Recently the US has begun to consider molecular-based enumeration tools as an alternative to 'tried and tested' albeit slower methods that rely on our ability to grow bacteria. This is likely to lead to increased pressure in the UK to consider a methodological shift too. However, with the emergence of rapid novel approaches come difficult decisions for how best to translate technological innovation into up-to-date regulation. As cutting edge science delivers new and more efficient technologies for microbial detection and enumeration there comes a requirement for balanced evaluation of such approaches with regard to their operational utility given their associated limitations and uncertainties at current time. For example, while molecular approaches provide rapid bacterial counts they have yet to be properly evaluated for regulatory monitoring purposes and there is much uncertainty regarding their precision and accuracy for microbial enumeration in the bathing zone. Without careful evaluation the same innovative science could actually bring about negative societal and economic impacts if implemented in haste due to poor understanding of how new and emerging techniques map onto existing health-related water quality standards. With more stringent standards drawing ever closer it is critical that science users and providers do not gamble with a methodological transition that could add further complications to the UK's compliance record.

A Working Group (WG) concerned with emerging quantitative molecular tools for microbial water quality compliance parameters has been formed in response to this challenge. The WG brings together experts from across academic, regulatory and stakeholder organisations to build a knowledge-sharing community. Using a workshop series, and drawing on wider national and international expertise, the WG will build an agreed evidence base to underpin and guide future decision-making in the short to medium term. Molecular tools will be interrogated via three themed workshops focusing on (i) the underlying science and technology of molecular tools; (ii) their potential to inform catchment management; and (iii) their economic impact. Members of the WG are already aligned to inform the World Health Organisation (which has been responsible for the development of revisions to the Bathing Water Directive for Europe) of outputs and recommendations from the project. Protecting public health is a priority. By ensuring that the science underpinning regulation and management of microbial water quality is transparent and thoroughly evaluated we can guarantee that the necessary steps are taken to benefit public health through reduced microbial risk from bathing and shellfish consumption.