Research Projects

Last revised: 28 June, 2004

Iowa Radon Lung Cancer Study Retrospective radon dosimetry Environmental  and building materials
Long-term indoor radon variations Radioactive material prospecting: Dating lake and river sediments:
Outdoor radon in central North America Outdoor radon in central Europe

Gamma attenuation of building materials:

Iowa Radon Lung Cancer Study

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) bd14565_.gif (183 bytes)TOP

Long-term indoor radon variations

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. bd14565_.gif (183 bytes)TOP

Outdoor radon in central North America

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). bd14565_.gif (183 bytes)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.bd14565_.gif (183 bytes)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. bd14565_.gif (183 bytes)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.bd14565_.gif (183 bytes)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.bd14565_.gif (183 bytes)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. bd14565_.gif (183 bytes)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. bd14565_.gif (183 bytes)TOP

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