Health Department slammed over sea bathing risks

The Department of Health (DoH) has emerged with its scientific credibility badly dented from an inquiry by the House of Lords Select Committee on the European Communities into a proposal to amend the 1976 EC Directive on bathing water quality. The Committee's report concludes that the DoH unjustifiably rejected recent scientific evidence that bathing in water meeting both the existing and the proposed tighter standards will give rise to significant risks to public health. But the

Committee is waiting for the Government to complete a study of the extra spending on sewage treatment which may be required by the EC proposal before judging whether the investment would be worthwhile in public health terms.1The Lords inquiry was particularly interesting because it looked into the European Commission's first proposal to amend one of the existing Directives which the UK has placed on its subsidiarity "hit-list".

The UK has argued that both the bathing and drinking water Directives are in need of wholesale amendment because they lack a sound scientific basis. The consequences of this, the argument goes, were not foreseeable at the time the Directives were agreed, but now that the Commission has made it clear that they have to be implemented to the letter, the costs involved are disproportionate to the benefits they will bring.

After looking into the proposal to amend the bathing water Directive, the Committee concluded that this, too, lacks a proper scientific basis, and has criticised the Commission accordingly. But its tacit verdict on the UK's position on the proposal is that, in pursuit of deregulation and cost saving, the Government has also closed its eyes to the latest scientific evidence.

The Commission's proposal was summarised in ENDS Report 231 (pp 42-43 ), and the crucial evidence submitted to the Lords inquiry in ENDS Report 234 (pp 17-20 ).

The central issue aired at the hearings was how far the existing Directive protects public health, and whether the Commission's proposal would confer any additional safeguards.

The DoH maintained that the current rules will give a "very modest" health benefit for a capital investment of £2 billion, and rejected any idea that they should be drawn tighter because no additional health benefits would accrue. In contrast, two leading overseas public health specialists argued that neither the existing nor the proposed Directives would ensure that bathers do no fall ill.

The argument was particularly sharply polarised over the proposal for a new limit of 400/100ml for faecal streptococci. Complying with this would pose a major challenge. In 1993, only 41% of the designated bathing waters in England and Wales complied with the existing non-binding guideline value of 100/100ml for these organisms.

The Government opened its attack on the proposal by claiming in its written evidence that a major UK study of the health effects of sea bathing reported by WRc had "found no relationship between health and the level of faecal stretococci when sampled according to the Directive's requirements."

In fact, this was a deliberate evasion. Under the Directive, samples are taken 30 centimetres below the surface in water one metre deep. But, as the WRc report also pointed out, the only consistent relationship established in the study between any indicator of water quality and rates of gastro-intestinal symptoms occurred with faecal streptococci when measured at chest depth. Moreover, this relationship became apparent at levels of 35-40/100ml, well below both the current guideline and proposed mandatory standards.

When questioned about this finding, Dr Judith Hilton (Senior Medical Officer, DoH) sought to play down its significance by saying that the odds ratio - the relative risk of disease symptoms in a group of bathers compared to non-bathers - was only around 1.5 in waters meeting the current EC standards. In epidemiological terms, she insisted, this was not a "significant" but at worst a "borderline" risk. And in any event, the illnesses involved were "trivial and self-limiting."

However, a note prepared for the Committee by its specialist adviser, David Kay (Professor of Environmental Science, Leeds University), came to a quite different conclusion. One feature of his analysis deals with several of the studies reported by WRc in which healthy adult volunteers entered bathing waters meeting the existing EC standards for a fixed period. Their health was subsequently monitored and compared with that of a group which did not enter the waters.

It was this research which identified a relationship between exposure to faecal streptococci levels measures at chest depth and rates of gastro-intestinal illness. The odds ratio for the group with an exposure of 35-70/100ml was around 2.0, while that of the group with an exposure in excess of 70/100ml was over 5.0.

According to Professor Kay, the results of these studies were "the first to suggest a scientifically credible dose-response relationship linking water quality and disease outcome for any recreational activity in EU waters. The purpose of such relationships is to allow objective environmental standards to be set. These results are certainly at variance with the policy stance taken by DoH."

The Committee agreed, using the polite language of the House of Lords. Its report says: "the Committee regrets as unjustified by the latest scientific evidence that the Department is...not yet giving sufficient weight to what the Committee regards as one of the key findings of the most recent research which they, with others, commissioned."

Neither does the Committee accept Dr Hilton's description of the illnesses acquired from sea bathing as "trivial". Such illnesses, it says, "may well cause inconvenience and disruption to daily or holiday life and be regarded as serious by the individuals concerned."

The Committee is also clear that neither the existing nor the proposed Directives do or would provide protection from self-limiting illnesses. For bathing waters meeting the current guide value of 100/100ml for faecal streptococci, the risks, it believes, "are broadly in line with other virtually irreducible risks from normally acceptable eating and living habits." However, in the many UK bathing waters which do not meet this guideline, "the risk of gastro-intestinal symptoms is higher than the risks the public meet in their normal daily life."

The Committee itself has declined to recommend at what level a binding limit for faecal streptococci should be set. The decision, it says, should be taken only after a public debate on health risks and the costs of meeting a possible standard.

However, estimates of the cost of the new proposal are not yet available. The Commission is criticised for not carrying out a cost-benefit assessment of its own. The Committee will publish a further report once it has received a compliance cost assessment which is being prepared by the Department of the Environment (DoE).

The Committee, though, was impressed by the evidence it received on the effectiveness of ultra-violet (UV) irradiation of sewage effluent in reducing pathogenic organisms to low levels. Surfers Against Sewage argued that this should be the preferred technology rather than conventional treatment and dispersal through long sea outfalls.

The Jersey authorities told the inquiry that a UV plant at the island's sewage works has consistently kept coliform levels in its effluent well below the EC standards for bathing waters. The plant cost £1.8 million. The alternative, a long sea outfall, would have cost £11 million.

Welsh Water also told the Committee that it has adopted a policy of full treatment and disinfection for 236 coastal sewage discharges in its region. Installation of the first five plants - four using UV and one micro-filtration - is due by mid-1995, with the first major installation, in Swansea, following in 1997. In addition, South West Water has plans to install UK units at 12 locations. And Anglian Water has just commissioned its first UV disinfection plant.

These developments are posing interesting questions about whether the water industry's general preference for long sea outfalls is economically and environmentally the correct option. It remains to be seen whether the DoE's compliance cost assessment will answer these.

Meanwhile, the Committee's other recommendations cover:

  • Viruses: The present Directive contains a zero limit for enteroviruses. This has made little impact because monitoring for viruses is limited. The new proposal would require monthly analyses - and this would result in a significant increase in breaches of the limit.

    The Committee has recommended that the zero standard should be dropped because tests for enteroviruses are uncertain and complex. A standard for bacteriophages - viruses of bacteria which may prove to be a good indicator of the presence of enteroviruses of concern - should be introduced instead when there is scientific consensus on the best organism to test for and on suitable analytical techniques.

  • Analysis: The Committee was told by scientists that the Commission had made no apparent effort to replace the out-dated analytical methods prescribed by the 1976 Directive. Its report pans the Commission for displaying "regrettable disregard of current science." It also urges the Commission to require all laboratories engaged in analysing bathing water samples to have quality assurance programmes and participate in external quality assessment to ensure that results are comparable across the EC.

  • Inland waters: The UK is the only EC state which has not identified any inland waters under the Directive. The report urges the Government to explain what criteria it uses in identifying such waters and proceed to make formal designations of waters meeting these.

    However, the Committee has rejected pleas from recreational interests that coastal and other waters used for recreational purposes rather than bathing should also be protected by the Directive. It says that reducing at source the organisms which cause health risks by UV or other treatment offers a better solution.

    The report also suggests a new system for grading bathing water quality to help educate the public about the nature of the health risks involved in bathing. It rejects as "unworkable" the Commission's proposal that beaches should be closed when there are "significant" breaches of the mandatory EC limits.

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