Water and sewerage services are supplied by the Northern Ireland Water Service (NIWS) and regulated by the Northern Ireland Drinking Water Inspectorate (DWI).

UK's poor relation
In its 1998 annual report, the NIWS boasted 98.9% compliance with statutory drinking water standards. But these figures conceal areas where compliance is far from impressive.

For trihalomethanes, for example, 72.6% of the 106 Province's supply zones failed the standards, as did 9.4% for pH and 8.5% for polyaromatic hydrocarbons. For aluminium, 21.7% of zones failed - compared with 1.4% in England and Wales and 9.7% in Scotland. The figures suggest that the Government is presiding over three distinct tiers of water quality.

Compliance with the aluminium limit in Northern Ireland is even poorer than these figures suggest. Some 44 zones in Belfast and County Down supplied from Silent Valley in the Mourne Mountains have been granted derogations under the EC Directive on drinking water on the grounds of situations arising from the "nature and structure of the ground". This allows aluminium concentrations of up to 500µg/l because the source is held to be natural.

The DWI says that treatment processes are not a factor in the high aluminium levels in water from the Silent Valley sources.

A spokesman told ENDS that the metal is not used as a flocculant in these supplies, and all of the aluminium present is natural, organically bound and unlikely to be bioavailable.

However, other aluminium exceedances in the Province are due to the use of the metal in water treatment. Poorly controlled flocculation leaves excessive concentrations in the supply, and the evidence is that the NIWS has exceeded legal limits for many years.

Aluminium exceedances
An investigation by the New University of Ulster into water quality in the Banbridge and Newry and Mourne districts of County Down in 1983 and 1984 found that aluminium concentrations rarely fell below 200µg/l. Average levels in the two areas, both supplied from Foffanybane treatment works, were 437 and 680µg/l, respectively, with a peak of 930µg/l. The supplies do not have derogations, and the high metal levels were apparently due to poor treatment methods.

Local councillors have remained concerned about the quality of water from the Foffanybane works. At their request, Environmental Assistance prepared a report on compliance with the aluminium limit in the Ards, Banbridge, Down and Newry and Mourne areas in 1997. Concentrations exceeded the legal limit in 11 out of 21 supply zones, including three derogated zones where they exceeded 500µg/l.

In February 1997, Banbridge District councillors conducted their own monitoring and found that supplies from the Spelga reservoir exceeded 200µg/l. The findings have exacerbated concerns that the water supply is being polluted by dumping of aluminium-rich sludges from the water treatment process. The NIWS said that "sludge spreading" in the catchment had been "customary practice for many years, without any evidence to suggest either environmental damage or health risk."

Accidents with aluminium
The NIWS has also had Camelford-like incidents. In June 1989, 25 tonnes of aluminium sulphate solution leaked from a storage tank at the Foffanybane works. An investigation ordered by the Department of the Environment found that the incident followed the failure of a ballcock valve in a dosing tank. A supply tank emptied itself into the dosing tank, causing an overflow into the site drains.

A similar incident had apparently occurred at the works in 1985, causing a massive fish kill in the rivers Muddock and Upper Bann.

The 1989 incident resulted in an estimated 1.65 tonnes of concentrated aluminium sulphate solution entering the water supply. The impact was apparent on pH monitors at a remote control centre. As at Lowermoor, the problem was ascribed to a lime dosing failure. Not until the following day was the cause realised to be the aluminium leak.

Aluminium levels in the supply averaged 7,000µg/l, but peaks of 10,000µg/l were measured at customers' taps. Levels remained elevated for three days, and the public was warned not to drink the water. The works was shut down and flushed.

No health effects were reported - something the DoE inquiry later claimed to be evidence of "the minimal extent of the [aluminium] pollution in the supply system." But there were major complaints from anglers about the effect on the river, which received a discharge of some 1.5 million gallons of contaminated water. A fish kill was reported as aluminium concentrations reached 13,200µg/l.

Other treatment works have also had incidents involving the supply of aluminium-polluted water. The NIWS has admitted that water with "higher than normal dosage of aluminium" was supplied by Lough Macrory treatment works to customers in Omagh in October 1998, but refused to furnish ENDS with details. However, the levels were high enough to prompt consultations with the local health authority and to warrant systematic flushing of the supply system.

Environmental pollution
The Foffanybane works has regularly polluted rivers with aluminium and other compounds. In addition to the 1985 and 1989 incidents noted above, another spill occurred in March 1996.

At this time the works was using a chemical flocculant Magnafloc LT31, four tonnes of which leaked out of a storage tank. An investigation by Queens University, Belfast, found that about a tonne of the compound escaped to the river, causing a significant fish kill.

Aluminium levels in the river Muddock were measured at the time of the spillage. Concentrations of up to 48,000µg/l were measured downstream of the work's discharge point.

Dr Chris Exley, a specialist in aluminium toxicity, commented that the concentrations "recorded at all sites below the water treatment works are several orders of magnitude higher than those recorded in the worst affected acid [rain] sites in Scandinavia and North America.". He expects them to have repercussions for aquatic life "for many years to come".

Despite its numerous failures, the NIWS told ENDS that it does not consider it "objective or fair" to say that Foffanybane had a poor record on drinking water quality or pollution. Work to upgrade it is due to begin next summer and be completed in 2002.

Lack of investment
According to the NIWS, the poor compliance with drinking water quality standards in Northern Ireland compared to the rest of the UK could be explained by "a very significant backlog of investment and the need for a substantially increased level of funding." This was a conclusion of the Service's 1994 asset management plan. Although the NIWS says that more funds have now been provided, its intention is to address the backlog "over a 15-20 year period".

The painfully slow progress is apparent in the Service's latest drinking water quality report. Of nine projects listed, seven are subject to "programmed delays", one is under review and another subject to construction delays. NIWS commented that its capital programme was "subject to continuous review and revision arising from a complex of factors relating to planning approvals, land acquisition, design review, revised estimates, unforeseen difficulties and delays on site etcetera, and for the need to prioritise and maximise the benefit from a finite level of funding."

Despite these difficulties, the DWI reports that aluminium compliance is improving. In 1996, 9.8% of samples taken at customers' taps failed the standard - or derogated standard - compared with 5.24% in 1997. Last year's figure was 5.17%.

"Cavalier" officialdom
Much of Northern Ireland's population has clearly been exposed to unlawful levels of aluminium for many years. However, the Province's Department of Health does not consider exceedances of the 200µg/l limit to be an issue.

The Department has set a "discussion level" of 1,500µg/l intended to trigger dialogue between NIWS and the health authorities, but this is based purely on aesthetic grounds. A spokesman said that at this level "aluminium was so high that it would cause other problems such as discoloration and palatability." There was "no real science behind it and we are not concerned about aluminium levels from a health perspective."

Environmental Assistance has called for an epidemiological study to investigate the incidence of Alzheimer's disease in the Province. At the Craigavon conference, Professor Daniel Perl, a neuropathologist from the Mount Sinai Medical Center in New York, described NIWS as "much too cavalier" about levels of aluminium in water.

The UK is in clear breach of EC law. In failing to meet the 200µg/l aluminium standard it breaches Article 3, but since the failures are due to the presence of a compound used in water treatment which may be a threat to health it may also be in breach of Article 8.