Environmental Health Perspectives 105, Supplement 6, December 1997

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Radon Exposures in a Jerusalem Public School

Elihu D. Richter,1 Ehud Neeman,2 Irwin Fischer,3,4 Mona Berdugo,1 Jerome B. Westin,1 Jackie Kleinstern,5 and Menahem Margaliot6

1Unit of Occupational and Environmental Medicine, Hebrew University-Hadassah School of Public Health and Community Medicine, Jerusalem, Israel
2Radiation Protection Division, Ministry of Environmental Quality, Tel Aviv, Israel
3Bar Ilan University, Ramat Gan, Israel
4Sanz Laniado Medical Center, Netanya, Israel
5Parents' Committee, East Talpiot Public School, Jerusalem, Israel
6Soreq Nuclear Center, Israel Atomic Energy Commission, Nahal Soreq, Israel

Abstract
In December 1995, ambient radon levels exceeding 10,000 Bq/m3 were measured in a basement shelter workroom of a multilevel East Talpiot, Jerusalem, public elementary school (six grades, 600 students). The measurements were taken after cancers (breast and multiple myeloma) were diagnosed in two workers who spent their workdays in basement rooms. The school was located on a hill that geologic maps show to be rich in phosphate deposits, which are a recognized source for radon gas and its daughter products. Levels exceeding 100,000 Bq/m3 were measured at the mouth of a pipe in the basement shelter workroom, the major point of radon entry. The school was closed and charcoal and electret ion chamber detectors were used to carry out repeated 5-day measurements in all rooms in the multilevel building over a period of several months. Radon concentrations were generally higher in rooms in the four levels of the building that were below ground level. There were some ground-level rooms in the building in which levels reached up to 1300 Bq/m3. In rooms above ground level, however, peak levels did not exceed 300 Bq/m3. Exposure control based on sealing and positive pressure ventilation was inadequate. These findings suggested that radon diffused from highly contaminated basement and ground-floor rooms to other areas of the building and that sealing off the source may have led to reaccumulation of radon beneath the building. Later, subslab venting of below-ground radon pockets to the outside air was followed by more sustained reductions in indoor radon levels to levels below 75 Bq/m3. Even so, radon accumulated in certain rooms when the building was closed. This sentinel episode called attention to the need for a national radon policy requiring threshold exposure levels for response and control. A uniform nationwide standard for school buildings below 75 Bq/m3 level was suggested after considering prudent avoidance, the controversies over risk assessment of prolonged low-level exposures in children, and the fact that exposures in most locations in the Talpiot school could be reduced below this level. Proposal of this stringent standard stimulated the search for a strategy of risk control and management based on control at the source. This strategy was more effective and probably more cost effective than one based on suppression of exposure based on sealing and ventilation. Because many Israeli areas and much of the West Bank area of the Palestinian National Authority sit on the same phosphate deposits, regional joint projects for surveillance and control may be indicated. -- Environ Health Perspect 105(Suppl 6):1411-1416 (1997)

Key words: radiation, radon, school, exposure standards, exposure control

This paper is based on a presentation at the International Conference on Radiation and Health held 3-7 November 1996 in Beer Sheva, Israel. Abstracts of these papers were previously published in Public Health Reviews 24(3-4):205-431 (1996). Manuscript received at EHP 2 May 1997; accepted 18 August 1997.

Address correspondence to Dr. E.D. Richter, Unit of Occupational and Environmental Medicine, Hebrew University-Hadassah School of Public Health and Community Medicine, P.O. Box 12272, Jerusalem, 911120 Israel. Telephone: 972 2 6758147. Fax: 972 2 6437219. E-mail: elir@cc.huji.ac.il

Abbreviations used: Bq, becquerels; pCi, picocurie; U.S. EPA, U.S. Environmental Protection Agency.

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