Maxey Flats

FIGURE 1. Experimental study area at the Maxey Flats shallow-land burial site. A series of experimental trench sections (T1-T5) and inert atmosphere wells (e.g. WIN) were installed adjacent to waste trench 27 to permit concurrent sampling of water from the waste trench (sump or well point), experimental trenches, and wells. 

Results of several radiochemical studies at the experimental study area we installed at Maxey Flats have already been described in detail elsewhere (8-10). The areal distribution of radionuclides in the surface soil throughout the site has been mapped. Groundwater flow patterns near the experimental study area have also been mapped using tritium as a groundwater tracer. 

In addition to the above studies, radiochemical analyses were performed on water which flowed into the experimental trench during its construction. Initial radionuclide concentrations in the water were comparable to those in water from waste trench 27 (Table I), indicating that subsurface migration of radionuclides has occurred over short distances on site at Maxey Flats. When the experimental trench was resampled later, the radionuclide concentrations were much lower, perhaps because the trench design perturbed the migration of radionuclides. Consequently, we installed and sampled a series of inert atmosphere wells around the experimental trench. 

Quite a variety of hydrophilic and hydrophobic organics have been identified to date in groundwaters from the Maxey Flats site, as listed in Tables III - VI. The chelating agent EDTA is the most abundant of the hydrophilic species, appearing in groundwater from three locations at ppm levels (Tables III and IV). It was identified in water from both waste trenches 27 and 19S (Table III). Water from waste trench 27 sampled on April 7, 1981, contained 1000 ppb EDTA whereas a more recent sample... 

TABLE III, Hydrophilic Organic Compounds a In Groundwater from Trenches at Maxey Flats... 

Groundwater from Experimental Wells at Maxey Flats... 

FIGURE 3. Steric exclusion chromatography of water from waste trenches and inert atmosphere wells at Maxey Flats, sampled July, 1982. Water samples from waste trenches 27 and 19S (440 ml) and wells WIN (585 ml) and W2NA (238.5 ml) were concentrated to 10 ml, pH-adjusted to their original values and chromatographed on a Sephadex G-15 column at flow rates ranging from 28-33 ml/hr. Individual column fractions were collected every 10 min and analyzed for specific organic compounds and radionuclides. 

Kirby, L. J. Ed. "Radionuclide Distributions and Migration Mechanisms at Shallow-Land Burial Sites 1981 Annual Report of Research Investigations on the Distribution, Migration ad Containment of Radionuclides at Maxey Flats, Kentucky," NUREG/CR-2383, 1982. 

Cleveland J. M. and Rees T. F. (1981) Characterization of plutonium in Maxey Flats radioactive trench leachates. Science 212, 1506-1509. 

At Maxey Flats, Kentucky, radioactive waste was buried in trenches. As rainwater infiltrated the soil, the trenches became saturated, and water containing dissolved radioisotopes began to move through the soil as the trenches overflowed. Assume a disposal trench overflow scenario that looks like the following diagram ... 

Plutonium levels in soils at Rocky Flats, Colorado, were analyzed by Little and Whicker (1978). Plutonium concentrations in soil samples collected to a depth of 21 cm had plutonium concentrations ranging from 1,400 to 59,000 pCi/kg (52 to 2,200 Bq/kg). A recent study on particle size and radionuclide levels in Great Britain soils reported plutonium-238 levels detected at a range of 200 to 18,000 pCi/kg (7.4 to 676 Bq/kg) and plutonium-239, -240 levels detected at a range of 800 to 83,000 pCi/kg (29.6 to 3,070 Bq/kg) (Livens and Baxter 1988). Core samples of surface soil at the Maxey Flats facility, where radioactive wastes were buried, were reported to contain a mean concentration of 1.9x10 pCi//kg (67 Bq/kg) of plutonium-238 and 22,000 pCi kg (8 Bq/kg) of plutonium-239 and plutonium-240 (NEA/OECD 1981). 

Meyer G. 1976. Preliminary data on the occurrence of transuranium nuclides in the environment at the radioactive waste burial site Maxey Flats, Kentucky. IAEA-SM-199/105. In transuranium nuclides in the environment. Proceedings of a symposium on transuranium nuclides in the environment. Vienna International Atomic Energy Agency, 231-270. 

Some of the better studied sites contaminated with Sr and Cs include (i) The Nitrate Disposal Pit at Chalk River Nuclear Laboratory in Ontario, Canada (ii) The A Disposal area at Chalk River the 100-K and 100-N area at the Hanford Site in Washington the 200 East area at Hanford, the 600 area at Hanford the Maxey Flats Low Level Waste (LLW) Site in Kentucky the West Valley LLW Site in New York, the Sheffield LLW Site in Illinois and the Barnwell LLW site in South Carolina. Barnwell is the only active LLW disposal site among those listed above. Surface water and soil contamination by Sr and Cs exists at Oak Ridge National Laboratory in Tennessee. There also is an apparently stable Sr plume at Brookhaven National Laboratory on Long Island. 

Dayal, R., R.F. Pietrzak, and J.H. Clinton. 1986. Oxidation-induced geochemical changes in trench leachates from the Maxey Flats low-level radioactive waste sposal site. Nuclear Technol. 72 184-193. 

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