IntroductionMost remedial technologies currently being used at hazardous waste sites (e.g., containment, excavation, soil washing, or incineration) are expensive. Further, in some locations technologies involving excavation could increase off-site releases of hazardous materials by destabilizing the site. Thus, interest in the development of in situ bioremediation technologies has grown substantially over the last decade. The idea of phytoremediation (Le., using plants to clean up toxic wastes) is generating increasing attention from scientists, industry, and government agencies. The attractiveness of phytoremediation stems from its potential (1) to be less expensive than technologies involving the human engineering costs of soil manipulation, and (2) to initiate simultaneously both the clean up of hazardous materials and site restoration (Stomp et al., 1993).The ability of plants to colonize and tolerate metalliferous soils has been known for some time (Antonovics et al., 197 1). Metal tolerant plants have evolved physiological mechanisms that generally do not suppress metal uptake but rather result in internal detoxification via two basic strategies (Baker, 198 1). In accumulators, metals are concentrated in aboveground parts regardless of soil concentrations. In contrast, excluders maintain aboveground concentrations that are constant and low over a wide range of soil concentrations by restricting transport from roots to shoots. Thus, the two strategies differ in their sites of detoxification (Le., roots in excluders and shoots in accumulators) (Baker, 198 1 the form of metal contamination to edaphic factors affecting soil sorption capacities (Miller et al, 1975;Barry and Clark, 1978).Most phytoremediation strategies will likely require metal tolerant plants of the accumulator type. The accumulation of metal contaminants in aboveground tissue facilitates plant harvest and, thus, cost-effective removal and disposal of the accumulated contaminants.Further, the identification or selection of "hyperaccumulator" plants (Baker et al., 1988) and the potential for similar genetically engineered capabilities (Stomp et al., 1993) offer some promise for the feasibility of such phytoremediation technologies. However, successful phytoremediation will also require species that (1) produce significant amounts of aboveground biomass, and (2) possess root systems capable of proliferating throughout and, thereby, extracting contaminants from the entire volumetric extent of the contaminated area.The purpose of this project was to investigate the potential for using plants to remediate J-Field soils contaminated with heavy metals. Phrugmites australis, one of the dominant species in the Toxic Burning Pits (TBP) area and other contaminated sites within J-Field, appears to be both tolerant of heavy metal contaminated soil conditions and capable of producing large amounts of biomass. Consequently, this project has concentrated on characterizing heavy metal accumulation by Phragmites australis growing in the TBP area relative to soi...

DISCLAIMERNUREGKR-5229 is not a substitute for NRC regulations and compliance is not required. The approaches andor methods described in this NUREGKR are provided for information only. Publication of this report does not necessarily constitute NRC approval or agreement with the information contained herein.

DISCLAIMERNUREGKR-5229 is not a substitute for NRC regulations and compliance is not required. The approaches andor methods described in this NUREGKR are provided for information only. Publication of this report does not necessarily constitute NRC approval or agreement with the information contained herein.

DISCLAIMERNUREGKR-5229 is not a substitute for NRC regulations and compliance is not required. The approaches andor methods described in this NUREGKR are provided for information only. Publication of this report does not necessarily constitute NRC approval or agreement with the information contained herein.

The Field Lysimeter Investigations: Low-Level Waste Data Base Development Program is obtaining information on the performance of radioactive waste forms. Ion-exchange resins from a nuclear power station were solidified into waste forms using Portland cement and vinyl esterstyrene. These waste forms are being tested to obtain information on survivability of waste forms in a disposal environment and to develop a low-level waste data base. Radionuclide releases from those waste forms during the first 9 years of sampling have been evaluated. Also, upward migration of radionuclides was recently discovered. Lastly, lysimeter data are applied to a performance assessment source term model.