Written Answers. - Drinking Water Quality Standards.


asked the Minister for the Environment if his attention has been drawn to studies which have recently been completed and published in Great Britain and Ireland on the relationship between the presence of aluminium in drinking water and the incidence of Alzheimer's Disease, with particular reference to the aluminium concentrations in Dublin's drinking water; whether Dublin Corporation monitor aluminium levels in drinking water; if the EC recommended levels and maximum levels have been breached; if so, the number of occasions on which they have been breached, if he will initiate a study of the number of occasions on which they have been breached, if he will initiate a study of (1) these results, (2) the reasons for them and (3) the possible implications of them in relation to Alzheimer's Disease; and if he will make a statement on the matter.


asked the Minister for the Environment if he will outline the Government's policy on acid rain; the effects of such pollution; the steps being taken by him and the Government to bring an end to this form of pollution; if his attention has been drawn to a report (details supplied) which links acidification and aluminium in drinking water with senile dementia and to further reports which linked various diseases to the intake of aluminium in drinking water; and the steps he proposes to take to bring this threat to an end in view of the clear link between acidification, the release of aluminium into ground water and diseases such as the aforementioned.

I propose to take Questions Nos. 22 and 115 together. I am aware of the studies referred to by the Deputies. The causes of Alzheimer's Disease have been under investigation for a number of years. One area of investigation involves a possible association between the disease and aluminium in drinking water. However, the recent studies published in Great Britain and Ireland have not established a casual relationship between the two.

Aluminium sulphate has been used worldwide for the past 50 years to clarify water and this method of treatment is the most common source of residual aluminium in water. Aluminium is also one of the commonest metals in the earth's surface and another area of investigation relates to the influence of acid rain in causing the metal to leach from soil into the environment and water.

In the case of Dublin's drinking water, Dublin Corporation monitor levels of residual aluminium on a daily basis, having regard to the quality standard set in the European Communities (Quality of Water Intended for Human Consumption) Regulations, 1988, which gave legal effect to the mandatory limit set by the EC. This limit is difficult to maintain where water treatment works are over-loaded or where filters are in poor condition. In Dublin, the Ballymore Eustace water supply cannot always be kept within the statutory limit for these reasons and slight breaches occur frequently, particularly in winter time.

Last month, however, I approved the acceptance of tenders by Dublin Corporation for major improvement works costing £14 millions at Ballymore Eustace Treatment Works. In addition to providing an extra 40 million gallons of water a day to the Dublin area, this major investment will ensure that the quality standards in the Drinking Water Regulations are consistently met.

In general, Ireland does not experience significant acid deposition, although elevated levels occur from time to time along the eastern seaboard when winds from the east predominate. Irish emissions of the principal primary pollutants involved in the creation of acid deposition, i.e. SO 2 and NO x, are relatively small and do not give rise to significant acidification problems here or elsewhere. Ireland supports moves at international level to deal with the pollutants in question through active participation in the EC Action Programme on the Environment and as a signatory to the 1979 Geneva Convention on Long Range Transboundary Air Pollution which aims to limit and, as far as possible, gradually reduce and prevent air pollution including long range air pollution. At national level, implementation of the Air Pollution Act, 1987, will contribute to the reduction of the emissions in question.

There is no evidence to suggest that acidification is effecting a release of aluminium into waters used for abstraction of drinking water in Ireland. Studies on acidification are being carried out by the Environmental Research Unit, and the issues involved will be kept under close review.


asked the Minister for the Environment if he will give details of the extent of monitoring of the quality of water in the Shannon Estuary; and if he is satisfied that the quality is within required safety limits.

In accordance with the provisions of the Local Government (Water Pollution) Act, 1977, monitoring or water quality in the Shannon Estuary is primarily a matter for the local authorities in the area of the estuary. In this case it is a matter for Limerick, Clare and Kerry County Councils and Limerick Corporation to draw up appropriate monitoring arrangements and to have them implemented. These local authorities have been co-operating in the preparation of a water quality management plan for the estuary and, in this context, a biennial water quality monitoring programme was carried out on a commissioned basis by An Foras Forbartha in 1983, 1985 and 1987. It is open to the local authorities concerned to make appropriate arrangements with the Environmental Research Unit or otherwise to carry out any further programmes of this kind which may be needed.

The studies carried out to date have shown a high water quality. The reportWater Quality in Ireland — the Current Position published in 1987 states that water quality was unimpaired in the estuary at the times of sampling, with the exception of some minor deterioration in the vicinity of Limerick. I am satisfied that water in the estuary is of a high quality and poses no danger to public health.