SCIENCE / Counting the cost of cleaner water: The EC is being lobbied to lower its standards for tap water. Are they unnecessarily high, asks Fred Pearce, or too expensive to implement?

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SCIENTISTS from privatised water companies in England and Wales are at the forefront of an unusual campaign - to persuade the EC to lower the standards that govern the cleanliness of tap water. They say the standards, which the Government has committed the companies to meeting in full by 1995, are often unnecessarily high, alarm the public and are causing growing anger as water rates soar to meet the cost of the clean-up.

Eureau, an international organisation of scientists that hopes to alter the EC's drinking water directive, held its first campaigning seminar in London in July. It was attended by EC officials and Mike Healey, Britain's chief drinking-water inspector. Other seminars will follow in other European capitals this winter.

The directive contains more than 50 individual standards covering everything from farm chemicals such as pesticides and nitrates, which percolate through the soil into once-clean underground water reserves, to iron from rusting water mains and chlorine, which is added at water treatment plants to kill bacteria.

'Some standards may need tightening, but others are unrealistic and unnecessary,' says Colin Skellett, managing director of Wessex Water in Bristol, who helped to organise the London seminar. It is not just the British who want to lower standards, he says. 'The French are very much involved, too. The whole European water industry is coming together on this.' But it is in Britain that the political pressure to cut the cost of keeping tap water clean is growing very quickly. The Government receives more complaints about rising water charges than about dirty water.

In July, Ian Byatt, the director of Ofwat - which regulates water charges - warned that meeting existing EC standards for drinking water could cost England and Wales an extra pounds 30bn between 1995 and 2005. Along with higher bills for cleaning up sewage in rivers, this will cause a 50 per cent rise in water charges before inflation, he said. Even tighter standards to produce what he called 'pure and green' water could cost a further pounds 20bn.

But Eureau's members claim that science as much as prudent housekeeping lies behind their call to revise the directive. Bob Breach, a senior water scientist at Severn Trent Water, told the London seminar that 'there had been an increase in scientific knowledge in the past 15 years,' since the directive was drafted.

The directive is undoubtedly tough in some areas. But are they the right areas? Derek Miller, of the industry's Water Research Centre at Medmenham, says money is being spent on unproven threats, at the expense of meeting known health hazards, such as lead (see box). He is particularly critical of the rules on pesticides, which the directive limits to one ten-millionth of a gram of any individual pesticide in a litre of water, or five times that amount for all pesticides combined. 'The pesticide standard is effectively a surrogate zero,' says Miller. 'Often you cannot even measure such low amounts.' The limit amounted to a 2-litre jugful of any pesticides in the entire daily water supply of England and Wales, which amounts to 20 billion litres.

Tap water in large areas of south and east England regularly exceeds the pesticides limit, most frequently because of the presence of the weedkillers atrazine and simazine. Peter Matthews, director of water services at Anglian Water, which pumps water from beneath Norfolk and Suffolk fields, said two years ago that 'about half our water supply exceeds the EC limit'.

Friends of the Earth says that the best way to tackle the pesticides problem is by not pouring so many toxic chemicals on to the land in the first place. Water industry scientists agree. 'We don't see why we and our customers should have to pay fortunes to clean up pesticides when the farmers don't pay a penny,' said one.

Meanwhile they say there is no scientific basis for building expensive new water treatment plants to meet the EC standards. 'The directive amounts to a statement that we do not want any pesticides in our water,' Miller says. 'But that is not practical at present, and there is no toxicological basis for trying to do it.' Critics at Friends of the Earth, such as water campaigner Liana Stupples, say that safety must come first. Many pesticides have not been on the market long enough for scientists to know their long-term toxic properties. Her view is supported by independent researchers. According to the UN's World Health Organisation, the effects of many pesticides 'will not be fully appreciated within the span of a generation'.

Stupples is involved in a propaganda war with the water companies about the cleanliness of British water. Last month, the Advertising Standards Authority upheld her complaint against the Water Services Association that a media campaign which called British drinking water 'the best in Europe' could not be substantiated.

Another imponderable for water scientists is the presence of trihalomethanes, or THMs, which are found quite widely in British tap water at above the EC limit. THMs form when chlorine, the standard disinfectant added in small doses to most British water supplies, reacts with tiny amounts of organic material in the water, such as peat.

A number of studies in the US in recent years have found what Robert Morris, biochemical statistician at the University of Wisconsin, recently called 'a consistent pattern of association between the consumption of chlorinated drinking water and both bladder and rectal cancers'. The main culprit appears to be chloroform, one form of THM, which according to Morris may cause 10,000 cancers a year in the US.

British water scientists stoutly defend the use of chlorine against alternative disinfectants such as ozone, though the latter has the added advantage of cleaning pesticides from water. 'Less chlorine has always been used here, compared with the US,' Miller says. 'And since 1974, when the Dutch discovered by-products, we've developed ways of minimising them.'

But German authorities have adopted a domestic standard for THMs that is four times tougher than the current EC limit of 100 micrograms per litre, which Britain still cannot meet. Eureau has yet to reveal its attitude to THMs, but it may suggest the adoption of a specific standard for chloroform, rather than tougher limits for all THMs. Critics argue that this may allow increasing amounts of other, perhaps no less dangerous, THMs to find their way into our taps.

A prime bugbear of the water scientists is the confusion in the directive between limits set on health grounds and those imposed for aesthetic reasons, such as removing the browny-red stain caused by bits of iron breaking loose from corroding water mains. 'It is very difficult for customers to understand that the current 1 per cent non-compliance with the directive mostly relates to aesthetics,' Skellett says.

Scientists wonder how much customers in the 'brown water' regions such as Yorkshire and the North West are prepared to pay for the stains to be removed. 'Replacing water mains is an immensely costly business,' Miller says.

Banishing iron can easily become a major part of the total cost of water supply. 'Obviously where there are chronic problems, we need to sort them out. But meeting the 100 per cent compliance required by the directive may not be a proper way of spending customers' money.'

Eureau says it wants to end the 100 per cent rule for so-called aesthetic standards. And it wants cutbacks in the three million tests made on drinking water each year, at a cost put as high as pounds 40m. Many tests are for chemicals, such as potassium and silica, that pose no hazard, are invisible and for which the limits are rarely if ever exceeded.

But those sums pale beside the billions of pounds being earmarked for the coming decade to meet a directive which, the water industry's scientists argue, is out of date and lacks scientific validity in crucial areas. The entire enterprise, they fear, could save only a handful of lives.

'We are not trying to weaken the directive,' Derek Miller says, 'but only to bring it up to date with current scientific knowledge. We want to weed out the redundant bits, add new parameters in some places - for example, to include bromine compounds - and to make others more specific. We want to spend money where there is good evidence of a risk to health.'

But the biggest problem for the scientists is that the directive includes no mechanism for updating its standards, whether to toughen or loosen them. Only a new initiative, approved by EC Commissioners and environment ministers, can bring about a revision. Above all, they fear bureaucratic inertia and a failure of ministers to grasp that nettle. Skellett says: 'We are sure of our case, but we are not sure that the political will is there.'-

(Photograph omitted)