Document NeOR75Zgk9gGpL8enOLr4Qx58

DEPARTMENT OF HEALTH. EDUCATION. AND WELFARE PUBLIC HEALTH SERVICE iATlQNA!. CEHTfB Pi anO Industrial health . EAST CENTRAL Parkway CINCINNATI. OH lO J5JQ2 Keren TO. December 7, 1967 Johns-Manvilie Company 22 East 40th Street Nev; York, New York 10016 . Gentlemen: We have had an inquiry from a local health officer about the carcinogenic effect of asbestos from A-C pipe in drinking water. We will decide about the effects of ingested asbestos, but would- like to know if you have any data about the amount of asbestos that might occur in drinking water. How much is introduced during pipe repairs and tapping? Does solution of the calcium out of the cement into the water release asbestos fiber? Do you know anything about a report "-that near Memphis, Tennessee, there was a pe riod in one locality where the pH in the \v-ater was 10 or 11 and this resulted in a solution in the cement compon ent of the pipes to such an extent that the water became milky-" that we have been asked about. I will appreciate your comments on this problem. r. Leland J. McCabe Chief, Disease Studies Water Supply and Sea Resources Program r P PNEUMOCONIOSIS KbSEAIiCll UNIT Visit by Medical and Science Correspondents Wednesday, 22nd February, 1967 mesotheliomas of the pleura and peritoneum. There is evidence that there is an increased incidence of cancers of the gastro-intestinnl tract; this has been produced by German and American investigators. The cancers of the lung occur in workers with severe asbestosis - fibrosis of the lung due to asbestos dust. In contrast to this the mesotheliomas enn occur in people with minimal fibrosis and, in some cases, asbestos is found in the lungs but insufficient to cause any scarring of tho lung tissue. In these people the exposure to asbestos dust is relatively slight, nnd may be nc little ns three months. In some cases, the exposure has been environmental, not occupational. The time between the exposure and tho development of the tumour jr> usually more than thirty yonrn. Those diseases are duo to the rthnlation of asbestos dust. There is no known dnngor through drinking water from sbestos pipes, or boor that has passed through asbcotoc filtorr,. Asbestos is a generic term applied to a number of fibrous silicates. Four types of this material are, and have been, used commercially in Britain. These arc chrysotile, crocidolite, nmosite and anthophyllite. Chrysotilc is by far the commonest type, the total world annual production being more than 5,000,000 to:i3; the main sources arc the SoviQt Union, Canada, South Africa, and Cyprus. Crocidolite (blue asbestos) is mined in South Africa and until recently in Western Australia the annual production is about 150,000 tons; the amount imported into Britain hap been reduced in recent years, audio now 7,500 ton3. Amocite is found only in South Africa where 100,000 tons are produced annually, the use of this fibre is increasing in Britain and about JO,000 tons was brought in last year. Anthonhvllite is mainly produced from a small mine in Finland, with an annual production of 15,000 tons; only a small amount of this is used in Britain. About 500 cases of cancer of the lung end mesothelioma are known to have occurred among people exposed .to asbestos dust in the United Kingdom, This is hardly significant when one realises that more than 25,000 casco of enreinnm of the lung are diagnosed each year. On current evidence from South Africa, Australia and Britain, it would appear that crocidolite is Eainly implicated in tho development of the mesotheliomas. However, cases have occurred in the United Stntco, Canada and a few in Britain in which the people concerned appear to have only been exposed to chrysotile. The ma.ior problem at the moment is to establish whether only one type of asbestos is responsible for the development of these tumours, and if other varieties can be exonerated. Exposure to only one type of asbestos is unusual in a manufacturing country such os Britain, therefore to find populations exposed to asinglc type of asbestos, surveys have to be undertaken in the mining areas. It is also hoped that information obtained from animal experiments may be valuable in the assessment of this hazard. Members of the staff of this Unit have played a prominent part in the discovery and investigation of the association between mesotheliomas and exposure to asbestos dust. They wero concerned in the original definition of the condition in South Africa, its recognition in Britain, nnd the dovolonmcnt of the international research programme which io now in operation. 1 jew/y 16.a.67 Pneumoconiosis Research Unit, Llundough Hospital, Penalth, Glamorgan.