Abstract |
Concerning the use of asbestos-cement (A/C) pipe for the distribution of drinking water, the status of the ingested asbestos health research underway in the U.S. Environmental Protection Agency is briefly described. At the present time there are no U.S. standards for asbestos in drinking water. The Agency has initiated regulatory proceedings to control A/C pipe as a result of a citizen's petition granted by the Administrator on Oct. 18, 1979. This means the Agency included A/C pipe in its overall assessment of asbestos as a toxic material. The primary reason for concern about drinking water containing asbestos fibers is the association between occupational asbestos exposure and gastrointestinal cancer shown in a number of occupational epidemiology studies. Although the asbestos worker is exposed to airborne asbestos it has been clearly demonstrated that a high percentage of inhaled fibers deposited in the lung are cleared and swallowed. So, they are also exposed to ingested fibers. There have been a number of recent studies which have shown that asbestos fibers can penetrate the digestive tract and even are excreted through the urine. Available studies and ongoing research are reviewed. |