More Plutonium Found in Park: Lab Says No Action Needed
by Marylia Kelley
Three times, soil samples have been collected from a city park near Livermore Lab and tested for plutonium.
Three times, the test results have come back positive. High levels of plutonium have been found - in the loose dirt in the park, along a baseball diamond that sits between the park and the adjacent elementary school and in a picnic area nearby.
And, three times, Lab officials have rushed to assert that there is no harm to human health or the environment from the plutonium, and that no cleanup or follow up action is warranted.
Plutonium is a man-made, radioactive metal used to create the atomic explosion that is at the core of a modern nuclear weapon. Plutonium 239, the bomb-grade isotope found in the park, has a radioactive half-life of 24,000 years. A material's hazardous life is generally calculated to be 10 times its half-life. Thus, plutonium is, in human terms, forever. The Lab has around 880 pounds of it on hand, enough for nearly 100 modern nuclear weapons.
There is no safe level of plutonium exposure. A microscopic particle, if inhaled, can cause cancer and other diseases.
A problem is discovered
Plutonium pollution was first discovered in Big Trees Park when the EPA analyzed a single dirt sample there. The EPA also took one sample each from two other Livermore parks. The agency expected all three to be at "background," and to use them as a comparison for known plutonium contamination at the Lab.
All 3 samples came up dirty, and the one from Big Trees Park contained the highest level of plutonium. Big Trees is about one-half mile west of Livermore Lab.
EPA uses a "background" range (representing global fallout levels from nuclear testing) of .001 to .01 picocuries of plutonium per gram of soil. The initial sample taken from Big Trees Park measured .164, between 16 and 160 times "background."
Amidst pressure from Tri-Valley CAREs and others, the Lab conducted a limited number of soil tests at Big Trees Park in 1995. Those test results turned up even higher levels of plutonium, including a finding of 1.02 picocuries per gram, up to 1,000 times higher than attributable to global fallout. The highest levels of plutonium were found in the top two inches of dirt in the park.
The EPA's "screening level" for plutonium in residential soil is 2.5 picocuries per gram. So, while elevated levels of plutonium have been found atop park soils in which children run, dig and play, the community has no regulatory mechanism to enforce cleanup. And, we still have questions about how the plutonium traveled to the parks and what the potential might be that other, undiscovered, "hot spots" are lurking within the community.
Health agencies come to town
Because the Lab is on the EPA's list of worst contaminated sites in the nation (the Superfund), the federal ATSDR (Agency for Toxic Substances Disease Registry) came to town to conduct a public health assessment. Working through a cooperative agreement, the California Department of Health Services and ATSDR together set up a "site team" to guide their assessment (which includes Tri-Valley CAREs' Stephanie Ericson), held public meetings and undertook to write a health consultation on plutonium in Livermore.
We shared our files with the agencies. In addition to data on plutonium in the parks, we had information about plutonium accidents at the Lab, including several where the radioactive metal had been washed down Lab drains and carried to the city sewage treatment plant. In a 1967 accident, the Lab estimated it sent a half-gram of plutonium to the sewage plant. >From '67 until the early '70s that plutonium-laden sludge was given to unknowing residents to use as fertilizer in their lawns and gardens.
The draft plutonium health consultation, released in 1998, discussed the sludge problem, pointing out that the Lab may have systematically underestimated the amount of plutonium in the sludge by failing to analyze the solids where it would likely concentrate. The consult also covered the plutonium pollution in Big Trees Park. Whether the health agencies will make final recommendations, and what those recommendations will be is the subject of a crucial public meeting on February 17. Your voice is needed. (See Citizen's Alerts on page 3.)
A third round of soil tests
Last year, again under pressure, Livermore Lab decided to undertake another, more thorough, series of soil tests at Big Trees Park. The sampling goal was two-fold: to find out whether there was more plutonium and to shed some light on how it got there.
Wind, water and contaminated sludge formed the three basic theories on how the plutonium got to the park. Airborne emissions from the Lab (due to accidents and/or routine operations) could have transported it there. If this is so, it is likely that other "hot spots" exist around Livermore. A second possibility is via the creek that cuts through the Lab before going past the park. Plutonium may have entered the creek as storm run-off and been tracked by kids and machines up into the park. Third, the Lab hypothesized, plutonium contaminated sludge could have been used on the ornamental trees when they were planted in the early 1970s. This was repeatedly denied by the sewage treatment plant and the parks district.
Late last month, Livermore Lab released the sampling results. High levels of plutonium were found at numerous sites in the park, near (but not in) the creek, along the ball field and by a little grassy hill between the park and the sidewalk. Somewhat elevated levels of plutonium were also found behind an apartment complex between the Lab and the park. The highest concentration of plutonium found was .774 picocuries per gram, up to 700 times "background," but below the EPA's screening level. Once again, most of the plutonium was found in the top two inches of dirt.
The Lab took samples in tree wells. No plutonium was found in samples about twenty inches deep, around the roots. So, the city was correct, and no contaminated sludge was used in their planting. The Lab took samples in the historic creek bed, covered over when the park was created and the creek was rechanneled. Again, no findings. The way the plutonium is distributed suggests that it may have traveled by air to the park. The hottest spots somewhat follow a line from the Lab's plutonium facility to the park, and in some cases, but not all, the highest concentrations fall out about forty inches or so away from the trees - which may have "captured" the airborne plutonium particles that then washed down when it rained.
Livermore Lab, however, is aggressively pushing a new sludge theory: Namely that an unknown resident had an unknown amount of contaminated sludge which he or she put around the trees at an unknown time after they were planted, for an assumed reason - to be helpful. The closer one looks at the Lab's "evidence" the more unlikely it seems. For example, the Lab found lower concentrations of other metals than you would expect to find if sewer sludge had been put on the trees. The Lab theorizes that the other metals washed away. One could go on. It's all possible, but not likely. In fact, the motivation seems political, not scientific. The Lab appears unwilling to consider that the pollution source may be the still-active plutonium facility and not a single, discrete occurrence from the distant past.
1. Sampling should be done of other likely "hot spots," including east of the Lab where plutonium has been found in off site air monitors. Samples should be analyzed for particle size to help determine the amounts of plutonium escaping through the filtering system. (More on filter problems in an upcoming issue.)
2. "Hot spots" should be cleaned up. There is no excuse for the Lab leaving elevated levels of plutonium in a park.
3. The Lab should institute changes in its filter maintenance and operational procedures in the plutonium facility to help minimize further releases.
4. The plutonium facility should rapidly be phased out of operation.
5. The California Dept. of Health Services should head up an investigation into where the contaminated sludge ended up. The Lab should pay for sampling on demand for any area residents who think they may have gotten plutonium-laden sludge for their home use.