You may recall that Andy Karam is the author of the 1999 paper "Calculations of background beta and gamma radiation levels over geologic time" in Health Physics 77(6):662-667 (in which he calculates that the early radiation background dose rate, during which life on earth evolved, was ~ 7 times today's...). He also wrote the paper "Gamma and Neutrino Radiation Dose from Gamma Ray Bursts and Nearby Supernovae" (not sure where that was published, although I do have an MS Word copy of it...).
The fear that Andy is talking about (below) is similar to what was experienced in the 1987 Goiania Cs-137 radiation incident (details of which appeared in the January 1991 special issue Health Physics journal, a 100-plus page (solid text) volume subtitled "The Goiania Radiation Accident" ).
As the specialist physicians of the Instituo de Radioprotecao e Dosimetria of Brazil explained, "participation of the doctors of the city of Goiania and the Hospital's medical staff itself... was greatly reduced due to fear or misinformation... instead of helping us by explaining exactly what was happening, and printing integral interviews with scientists working on the project... irresponsible yellow journalism stirred fear in the population ...hysteria instigated by the media was very expensive for the government and extremely painful to those involved... the victims of Cesium 137 were rejected by an entire city and its population... as much discriminated against by society (as are) AIDS patients."
Sent: Monday March 18, 2002 10:30 AM
To: 'RadSafe Listserver'
Subject: ENN repost from Inside Science News Service
A dirty bomb "would probably not lead to many, if any, cancer deaths," says
Andrew Karam, radiation safety officer of the University of Rochester in
Rochester, NY. ...
Health Physicist Says 'Dirty' Bomb's Greatest Danger Is Fear
From Inside Science News Service Friday, March 15, 2002
ROCHESTER, NY - The latest post-9/11 disaster scenario making news headlines is the "dirty bomb." The theoretical situation occurs when terrorists get hold of radioactive material from a hospital or food-irradiation plant, attach it to an explosive, and detonate the bomb in an urban area. The explosion spreads the radioactive material all over a city and exposes the population to radiation. Yet according to a health physicist, the biggest health risk from a dirty bomb would not, reassuringly, be cancer, but something more preventable: panic.
A dirty bomb "would probably not lead to many, if any, cancer deaths," says Andrew Karam, radiation safety officer of the University of Rochester in Rochester, NY. But if the public receives unreliable or exaggerated information about dirty bombs, Karam worries that "the use of a radiological weapon would result in many deaths in traffic accidents as people flee the scene, and possibly stress- and anxiety-induced heart attacks." [ comment: you have two guesses about who does the exaggeration & indirectly causes these deaths...]
The radiation dose from a dirty bomb would likely be relatively small, says the Rochester health scientist. Even a potent dirty bomb, consisting of a radioactive cobalt-60 rod used for food irradiation, for example, would deliver an average dose of a few tenths of a rem for people within a half-mile radius, he says. (A rem is a unit of radiation dose.) This compares to the 0.3-0.4 rem average dose per year that a person receives from natural sources, and 5 rem, the typical annual dose limit for nuclear and radiation workers (most radiation workers receive less than 1 rem of exposure annually).
Some recent news accounts have predicted that dirty bombs would cause a small amount of additional cancer cases. However, Karam says these estimates are all based on a faulty assumption.
"They are based on the use of a concept called 'collective dose,' the concept that exposing a large number of people to very low levels of radiation will result in a certain number of cancer deaths," he explains. "By analogy, we can say that throwing one small stone at each of a million people will result in crushing one or two people because the combined weight of all the stones adds up to a ton, which is enough to crush someone."
Karam notes that the Health Physics Society, a professional organization comprised of over 6,000 radiation safety professionals, has advised against calculating risk from exposure to low levels of radiation (less than10 rem). The International Council on Radiation Protection (ICRP) has similarly advised against calculating risk to populations when the highest-exposed person in that population receives a small dose.
"The radiation exposure to people in the wake of a radiological attack is much less than the doses to which both the Health Physics Society and the ICRP refer," Karam says. "The best way to protect ourselves against radiological terrorism," he adds, "is to make sure the public and emergency responders are provided with the best information."
Andrew Karam, Radiation Safety Officer, University of Rochester, 585-275-1473, Andrew_karam@urmc.rochester.edu
Health Physics Society Papers (select "Radiation Risks in Perspective")
For more information, contact:
Ben Stein, Science Writer, Inside Science News Service. (301) 209-3091 firstname.lastname@example.org
Web site: http://www.insidescience.org