Friday, April 15, 2011
On Tuesday Japan raised the severity rating of the Fukushima nuclear crisis
to 7, putting it on a par with the 1986 Chernobyl disaster. Although Japan
is releasing few details, you can safely conclude that radiation is really
bad; beyond that you're on your own. The most up-to-date and comprehensive
risk estimates for cancer and other health effects from exposure to low-
level ionizing radiation are in the 2006 Biologic Effect of Ionizing
Radiation Report of the National Academies (BEIR VII). The only data base
we have is from victims of massive exposures at Hiroshima and Chernobyl.
The report relies on the linear-no-threshold model to estimate the risk
from multiple exposures at much lower levels, such as airliner crews. This
is not only wrong, they know it's wrong. A DNA repair process is
constantly at work in human cells repairing DNA damage from sources of
ionizing radiation, including UV light and cosmic radiation. There is not
much choice but to ignore the repair process and assume a linear model
which greatly overstates the risk from multiple exposures. A panel of
experts concluded that that, "the preponderance of evidence indicates that
there will be some risk even at low doses."
I've been living in the past, grousing about the failure of "the media" to
expose the public to the facts about cell phone radiation and cancer.
That used to mean a trusted figure like Walter Cronkite on the evening
news, a segment on 60 Minutes or Sunday Morning, and an in depth feature in
the New York Times. Television news is now kept busy keeping us informed
about celebrities checking into rehab; print news now means an army of
bloggers. The best coverage of the cell phone thing so far was an article
this week in the New York Times Magazine by Siddhartha Mukherjee, "Do Cell
Phones Cause Brain Cancer?" In the age of twittering I don't know if
anyone still reads 17 page articles, but Mukherjee remains calm through it
all and in the end concludes the evidence is far from convincing. That's
the way it is with epidemiology, always a little wishy-washy. It's like
deciding the winner of the Super Bowl by a show of hands from the crowd.
The authority of the Environmental Protection Agency (EPA) to regulate
greenhouse gas emissions under the Clean Air Act would have been stripped
by legislation that easily passed the Republican-controlled House a week
ago. The following day, however, the measure was defeated in the Senate.
But no one is celebrating yet. Republicans will now try to cut EPA funding
to prevent money from being spent on the measure.