TOPLast revised: 28 June, 2004
Dr. Charles Lynch of the Department of Preventive Medicine at the University of Iowa is
the principal investigator in this case_control epidemiologic study of radon, diet, and
lung cancer among women in Iowa. . Dr. Steck is an co-investigator along with Drs.
R. William Field, and Robert Woolson ( U. Iowa), and Dr. John Neuberger ( U. Kansas-KC).
The data collection phase of the project began in 1992 and ended in 1997. The
analysis of the risk of lung cancer from radon gas exposure will be published in May 2000
in the American Journal of Epidemiology. The study found a significant
association between radon gas exposure and increased lung cancer rates in Iowa women. The
study also used integrating track registration dosimeters (called Retrospective
Reconstruction Detectors:RRD)that the Minnesota radon Project pioneered. These detectors
use the implanted 210Po activity in glass and the
deposited 218,214Po activity to reconstruct past
radon concentrations and radon-related dose. The analysis of the risk of lung cancer from
the radon progeny exposure reconstructed from RRDs is underway. ( CHEEC project) TOP
The annual average radon concentration in the two lowest levels in ~ 100 Minnesota
homes has been monitored during the 1990's in order to quantify the year-to-year
variations. Most of these homes were first measured in the mid 1980's. This project
is scheduled to run until 2000. Preliminary results are: average year-to-year variations
are approximately 25% in both the basement and first floor. The observed range of the
annual variation in the group of houses is from 5% to 150%. Some houses show a systematic
change in radon. Some houses show a dramatic change when they are renovated. We're
studying possible correlation with climatic changes. TOP
How good is the "rule of thumb" that the radon concentration outdoors is low,
0.4 pCi/L? We used ATD detectors in Minnesota and Iowa to measure, and map, outdoor
radon concentrations. We had about one measurement in every county in Iowa. In Minnesota,
we studied more localized variability and found it to be small. We found that there were
sections in the western part of both states where the outdoor radon concentration was
higher than it is indoors in most places in the world. . The outdoor radon map is quite
similar to the indoor radon maps (see NAOUTS). TOP
Outdoor
radon in central Europe
Dr. Pavel Szerbin and Zoslt Deri of the
"Frederic-Joloit-Curie" National Research Institute for Radiobiology and
Radiohygine are collaborating with us in a 100 point survey of the annual average outdoor
radon gas concentrations in Hungary. The project will run from Fall 1999 through the Fall
2000.TOP
Retrospective radon dosimetry using glass implanted 210Po
Past radon and radon progeny atmospheres can be reconstructed from 210Po
implanted in domestic glass surfaces See the Publications
page for technical references (Steck
and Lively, 93, Steck and Field, 99).This promising technique has a number of
possible limitations. Many of these possible limitations are difficult to study in the
laboratory since they depend on the variety of atmospheric conditions that can be found in
different homes. We are simulating some of these in the laboratory and also collecting and
measuring glass surfaces from our long-term radon houses since they will have a
well-documented long-term radon exposure in actual domestic atmospheric conditions.
Currently we are also studying the relationship between long-term integrated radon gas
exposure and implanted activity in houses in Minnesota and Finland. Other researchers from
the Swedish Radiation Institute and University College Dublin are collaborating in
these studies. We hope to have all the world's glass-based retrospective reconstruction
systems intercalibrated. TOP
Radioactivity
of environmental samples and building materials: rock, soil, water
Where's that radon and gamma radiation coming from? To assay the radionuclide content and
emanation rates, we've measured the natural and man-made gamma emitting radioisotope
contents of hundreds of samples of rock, soil, and water from throughout the upper
Midwest. We've also investigated a few kinds of cements, concretes, wood (and ash), and
building stones (mostly granites) to determine their contributions to the radon and gamma
ray exposure in homes. PS. Granites have an undeserved reputation for being a major source
of radon in our region. Currently we are measuring an extensive set of glass samples to
determine the range of intrinsic radioactivity in domestic glass.TOP
Dating
lake and river sediments:
The atmospheric testing of nuclear weapons has left one valuable legacy; sedimentation
rates can be determined in some modern bodies of water. 137Cs , generated by
the testing, began depositing in North America in 1954, reached a peak in 1964, and then
stopped. In Minnesota, 137Cs concentrations in sediment deposited after 1954
range from a few Bq/kg to over 100 Bq/kg in lakes and rivers. Thus, in a core sample one
can usually determine the depth of 1954, 1964, and the present and calculate the average
sedimentation rate for two recent intervals.TOP
Natural and anthropgenic radioactive material prospecting:
Looking for radioactive waste dumps created by Mother Nature or XYZ Inc. ? We've had some
experience looking. We've used simple and sophisticated instruments, some portable, some
carborne ( see Surface Radiation Maps), and some lab
analysis to prospect for enhanced concentrations of NORM materials such as veins of
pitchblende and uranium contaminated slag. PS . We've found some from both waste
generators. TOP
Gamma
attenuation of building materials:
Systems that isolate bulk quantities of high-level radioactive sources often rely on large
quantities of common building material like soil and rocks. These systems should be stable
against a variety of environmental attacks including earth quakes and floods. We tested
the shielding ability of a particular kind of building stone to quantify its gamma ray
attenuation coefficients for a company that was designing a radioactive waste storage
system. TOP
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