Shawn Smallwood, PhD, of the University of California at Davis, came to the Rocky Flats site on three separate occasions, each of several days in length, to study “bioturbation” at Rocky Flats, that is, natural processes of wildlife and plant life that disturb the physical environment. He documented the presence of 18 species of burrowing animals present at the site, everything from harvester ants to pocket gophers, prairie dogs and pocket gophers.
Archive for April, 2011|Monthly archive page
Rocky Flats Nuclear Guardianship #6: Marco Kaltofen, Plutonium in Respirable Dust With Harvey Nichols & Gale Biggs 3-17-11In Environment, Nuclear Guardianship, Plutonium, Public Health, Rocky Flats, Wildlife Refuge on April 1, 2011 at 7:22 am
There has never been a program at Rocky Flats either on or off site to sample respirable dust in surface of the soil and to test discrete samples for their plutonium content. Once in the history of Rocky Flats Carl Johnson, then Director of the Jefferson County Health Dept., and two colleagues from USGS sampled respirable dust at an off-site location east of the site. The results of this sampling showed concentrations of plutonium in on average 44 times higher than whole soil samples collected at the same locations by the Colo Dept of Health. When the Jefferson County Commissioners saw the results they vetoed a residential development that the Colo Dept of Health had already approved. Johnson tried without success to get the State to adopt the method of sampling respirable dust for its assessment of plutonium in soil at off-site locations.
Before Marco Kaltofen spoke we heard from biologist Harvey Nichols and meteorologist Gale Biggs, both local scientists who did important research at Rocky Flats in the 1970s and 1980s. Nichols, who is a specialist on tracing the aerial migrations of very tiny materials, such as pollen and pine spores, was asked in the mid-1970s to research radioactive particles released from Rocky Flats. He determined that literally billions of minuscule particles were dispersed throughout the Rocky Flats site and beyond. In the process of his work he examined the air monitoring equipment used at Rocky Flats and found it grossly inadequate. In the 1980s Dr. Biggs was appointed by then-Governor Roy Romer to assess airborne radiation at RF. His presentation described quite methodically how he went about this task. For his study he focused primarily on releases from routine operations from the plant stacks. Monitors within the stacks failed to measure actual quantities of material passing through the stacks because they were improperly installed. Second, once particles of plutonium exited the stacks they likewise were not accurately recorded by air monitoring devices because the larger particles dropped to the ground before they could reach the monitors and the smaller particles, which made up the overwhelming majority of releases, were not detected because they were so small they passed right through the filters in any monitors they might reach. His research thus underscored the conclusion reached earlier by Dr. Nichols that the publicly reported results of monitoring of airborne Pu from Rocky Flats greatly misrepresented reality in a way that falsely assured the affected public rather than telling them the truth about airborne releases from the plant.
Marco Kaltofen of the Boston Chemical Data Corp. and the Worcester Institute of Technology has done sampling of respirable dust at several sites where plutonium is in the environment — Hanford, Los Alamos and Mayak in Russia. He analyzed a dust sample that was collected in April 2010 by Todd Margulies and myself in crawl space of a house about a mile east of Rocky Flats. His analysis showed that this sample contained hot particles with high concentrations of plutonium. In the talk he gave he described how when he has a sample of soil he spreads it out on a large piece of film in a dark room and leaves it there for about 48 hours. When he then looks at the film he can see where radioactive particles are present and which ones have the highest concentration of radioactivity. He then analyzes particular particles for the strength of the radioactivity and the specifics of the material — that is, identifying the particular isotope of a given radionuclide. He describes quite beautifully how particles break down, as if they were being sliced several times vertically, then several times horizontally. Though the result is many small particles, one of the features is that far more surface is exposed in the many particles than if they were compressed into one. My impression is that this meant there’d be more overall radiation given off than would happen with a single particle. His approach makes it possible to quantify very low-level environmental radiation. He can distinguish radiation produced by human activity from naturally occurring radiation. For instance, in two of the Rocky Flats samples that Todd and I collected and sent to Kaltofen for analysis he found thorium that most likely came from Rocky Flats because it lacked the characteristics of naturally occurring thorium, containing instead the characteristics of industrial processing. This was a surprise to me and others who have followed the RF issue closely for years because we never knew that processing with thorium had once happened at RF.
The import of Kaltofen’s work is that he signifies a type of sampling that needs to be established at Rocky Flats. One of the goals of RF Nuclear Guardianship project is to see a long-term program of testing respirable dust in surface soil for its Pu and americium content. The need for this is underscored by the findings of Nichols and Biggs as well as by the next speaker in our series, Shawn Smallwood, whose topic is burrowing animals in the environment at Rocky Flats.