NORTHERN ARIZONA UNIVERSITY
Wayne State University
To: Parties Concerned about the Industrial Excess Landfill, Uniontown, OH
The intent of this letter is to clarify several matters relating to the apparent presence of plutonium (Pu) in the Industrial Excess Landfill Site. It is apparent that EPA and other government agencies have focused mainly on the drinking water standards for gross alpha activity, and have not considered the true underlying issue, namely, whether the presence of Pu in the IEL groundwaters represents a non-natural situation. As scientists who have specifically studied and researched numerous issues relevant to environmental Pu, we would like to discuss several points. Our hope is that members of the public community will consider all technical view points that have been expressed to date.
1) There appears to be a lot of attention paid to whether Pu can or does contribute to the gross alpha activity drinking water standard or not. First of all, the gross alpha standard is designed as a crude evaluator of the general presence of naturally occurring 238 U series radionuclides, and was never intended to evaluate the activities of anthropogenic alpha emitters such as 238+240 Pu. To apply this gross standard to a: specific, non-naturally occurring radionuclide such as Pa, while neglecting to set an ; appropriate activity standard for 239+240 Pu (that is meaningful in the context of background), is fraudulent in both the scientific and regulatory senses.
2) EPA has long maintained the position that, since 239+240 Pu activities are less than this gross alpha standard, it must represent a “background” occurrence rather than a situation that is locally unusual. One must first consider the origin of background plutonium, namely, 1950’s-1960’s atmospheric testing of nuclear weapons. These tests have globally distributed Pu in surface soils at activities on the order of 1 Bq/kg 239+240 Pu It is not reasonable to expect that these activities in surface soils, and even lower activities in the subsurface environment, can account for any significant concentrations of 239+240 Pu in water. Indeed, many studies of 239+240 Pu in water have determined “background” 239+240 Pu activities several orders of magnitude lower than EPA’s gross alpha standard. There are two reasons why 239+240 Pu activities in “background” waters are so low: 1) the activities in soil are very low to begin with,, and B) 239+240 Pu is highly particle reactive, and it tends to stay associated with solid phases and dissolves to only a very limited extent.
3) When 239+240 Pu is found in groundwater at levels above “background”, it has been found: to originate from some specific local source. While the analytical data produced by: — USEPA and Ohio EPA over the past >10 years do not adequately address whether Pu is present or not, there is at least the indication of the possible presence of 239+24O Pu at ~ elevated levels, which is not disproved by the collective data.
4) Since the IEL data do not disprove, and to some extent suggest, that 239 Pu is present at elevated activities in JEL vicinity groundwater, the key unaddressed questions are:
A) Is non-background Pu present in soils and groundwaters at IEL?
B) Where is it present and in what physicochemical and isotopic forms?
C) How did it get there?
5) The situation at another site, the Nevada Test Site (NTS), are relevant to the present questions about IEL. At NTS, 828 underground nuclear tests were conducted between 1956 and 1992 and as a result, NITS contains a large inventory (>100 million curies) of radioactive material deposited in the subsurface ( Kersting et al., 1999). Kersting et al. (1999) reported Pu concentration in the groundwater samples to be -0.2 to 0.5 pCi/L (data extracted from the figure showing the Pu concentration in unfiltered water in Kersting et al_, 1999). Kersting et al. (1999) showed that Pu and other radionuclides are transported as colloidal material in the groundwater samples collected from the Nevada Test Site. They suggested that Pu is sorbed onto the colloidal sized clays in the ground water. These workers clearly demonstrated that the Pu found in the groundwater is only a very small portion of the total Pu associated with the nuclear test site.
6) If the highest 239+240 Pu activity reported at the IEL site (0.31 pCilL) is taken at face value, then, it behooves us to ask how much 239+240 Pu is contained in the subsurface environment at the IEL site. This should be a major concern to everyone and the public stakeholders deserve a valid, scientifically defensible answer to this question.
7)It is hence our opinion that this question can only be answered by new high-volume water sampling, tests for the presence of colloidal Pu, and mass spectrometric measurements of activities and isotopic fingerprints of the Pu’s origin.
In view of the gravity of the situation, we believe that responsible agencies need to focus, in a definitive manner, on the possible presence of non-background Pu in IEL soils and subsurface waters. It is irrelevant to focus meaningless attention on whether Pu significantly contributes to the gross alpha activity. In our opinion, in the near future, Pu will not contribute significantly to the gross alpha activity in drinking water, while the not-disproved subsurface Pu will remain a buried threat to humans and biota for future millennia.
Michael E. Ketterer, Ph.D.
Associate Professor of Chemistry
Northern Arizona University Flagstaff, AZ 86011-5698
[email protected]
Phone (928) 523-7055
Mark M. Baskaran, Ph.D.
Associate Professor of Geology
Wayne State University Detroit, MI 48202
[email protected]
Phone (313) 577-3262
Reference: Kersting, A. B., Efurd, D.W. ; Finnegan, D. L. ; Rokop, D. J. ; Smith, D. K. ; Thompson, J. L. , Nature 1999, 397, 56-59.