§ Mr. John Evans
asked the Secretary of State for the Environment if he is yet in a position to make a statement on the survey of lead in water being undertaken by his Department.
§ Mr. Denis Howell
It has been known for many years that the level of lead in tap water varies from house to house. The present upper limit for lead in drinking water recommended by the World Health Organisation is 0.1 milligrammes per litre. This limit was fixed in 1971 on the basis that people had lived with water at this level for many years without apparent ill effects. There is no evidence that lead at 0.1mg/1 in water is of itself harmful.
The WHO and the European Commission are proposing to halve this limit in a general desire to reduce exposure to lead from all sources, and the Government therefore decided, after consultation with the water industry, that it would set up a survey of the current levels of lead in water to ascertain the implications of this step; 2,400 households in England and Wales were included in the survey and we were grateful for their co-operation.
The first results of the lead in water survey show a varied picture. This is not surprising because, while water supplied by water authorities in this country has levels of lead well below the recommended and proposed limits, lead can be picked up before it reaches the tap. For example, the levels can be affected by such factors as the length of time for which water has been standing in pipes in or leading to the property. From these first results it appears that less than 3 per cent. of households in England and Wales have water lead levels higher than the present WHO limit in samples taken during the day. These are to be found in both hard and soft water areas.
While the detailed results are being analysed to obtain the full picture the 629W Government consider it is desirable to proceed to an examination of what is the key issue—the levels of lead in tap water in relation to the levels of lead in blood of the human body.
The Government, therefore, propose to establish an epidemiological survey to examine the relationship between lead in water and lead in blood and it is hoped that this will be completed towards the end of the coming year. Meanwhile a pilot study of lead in water and lead in blood is being put in train to help shape the epidemiological survey. This pilot study will involve asking a sample of the participants in the 2,400 survey to undergo a simple test. The Government hope that all those invited to take part in this pilot study will feel able to do so. Water authorities and participating water companies undertook at the beginning of the survey to notify householders in the households samples where water levels have been shown to be high and they will be advising them about the action that is desirable. Usually this will simply mean not drinking water which has been standing for some hours. The individual results of the water survey will, of course, be communicated to the local authorities concerned, because of their statutory responsibility for the wholesomeness of water in their areas, and to medical officers for environmental health.
It is hoped that the detailed results of the water survey together with those from the pilot study of blood lead levels, will 630W be published in about three months' time. The results of the epidemiological survey will also be published as soon as they are available.
The survey of the lead content of water extended to Scotland where over 500 households were sampled and the follow-up action will also extend to Scotland. Preliminary results suggest that some 20 per cent. of the samples had lead levels above WHO limits.