Estimation of the release and migration of lead through soils and groundwater at the Hanford Site 218-E-12B Burial Ground. Volume 2, Appendices

Abstract

from the ROCSAN database (WHC Iggl). The wells used and the characterization data associatedwith each well are listed in Table A.I. Figure A.3 is a location map of the boreholes In the vicinityof the burial ground. Cross sections,located in Figure A.3, that show the interpretedsubsurface stratigraphybased on the data from these wells are presentedin Figures A.4 and A. 5. In addition to borehole studies, detailed observations were made and samples were collected from the excavated exposures of the 218-E-12B Burial Ground itself. A geologic map (Plate A.1) of the exposed burial ground wall was prepared and samples of the different lithologic types present were collected for a variety of laboratory analyses. These analyses include grain-size distribution, moisture content, porosity, permeability, bulk density, clay mineralogy, and bulk geochemistry. The analyzed samples are listed in Tables A.2 and A.3 and were collected from locations shown in Plate A.1 and Figures A.6 and A.7. Data from the completed analyses are provided in Appendix B (Parts 1-5). For comparison with outcrop samples, similar analyses were performed on selected samples of borehole cuttings obtained from two wells immediately adjacent to the 218-E-12B Burial Ground (299-E35-1 and 299-E34-7, Figure A.4). Completed analyses are reported in Appendix B (Parts 4-6). A.2.1.1 Columbia River Basalt Grouo The Columbia River Basalt Group is an assemblage of tholeiittc, continental flood basalt flows of Hiocene age. These flows cover much of the Columbia Plateau, which includes an area greater than 163,700 km z (63,000 mi2) tn Washington, Oregon, and Idaho, and have an estimated volume of about 174,000 Ion a (40,800 mta) (Tolan et al. 1989). Isotopic age deteminations indicate that basalt flows were erupted from approximately 17 to 6 million years before present (Ha). More than 98%of thts volume was erupted in a 2.5million-year period between 17 and 14.5 Ma (Reidel et al. 1989). The youngest basalt flows in the vicinity of the 218-E-12B Burial Ground belong to the Elephant Mountain Memberof the Saddle Hountains Basalt, which is about 8.5 Ha (HcKee et al. 1977).

Saturation‐matric potential relations in gravel

“…These Hanford formation gravels and sandy gravels were deposited during cataclysmic floods released from Pleistocene ice‐dammed lakes. Samples were excavated from Site 218‐E‐12B, in the north‐east corner of the 200‐East Area [ Rhoades et al , 1992]. Gravels were sieved into 8.0–9.5, 4.8–5.3, and 2.0–2.4 mm size fractions for testing of approximately monodisperse media.…”

“…Gravels and coarse sands make up significant portions of some environmentally important sediments. For example, the Hanford formation vadose zone underlying radioactive waste tanks in south central Washington State contains substantial regions characterized as coarse sands, gravelly sands, and sandy gravels [ Rhoades et al , 1992]. Well‐sorted, coarse‐textured media are also main components in capillary barrier designs for minimizing seepage through wastes buried in the subsurface [ Conca et al , 1998].…”