Burial trenches at the Maxey Flats radioactive waste burial site cover an area of about 20 acres, and are located on a plateau, about 300 to 400 feet above surrounding valleys. All waste is buried in the Nancy Member of the Borden Formation, and most is in the weathered shale (regolith) part of this member. Recharge to the rocks is probably by infiltration of rainfall through regolith at the top of the hill. At least two water tables are present: near the base of the regolith, at a depth of about 25 feet and; in the Ohio Shale, at a depth of about 300 feet. About 95 percent of ground-water discharge to streams is from colluvium on hillsides and valley alluvium. The remaining 5 percent is discharge from bedrock, of which about 0.5 percent is from rocks underlying the burial area. Waste radionuclides in the subsurface, other than tritium, were observed only in the regolith of the Nancy Member. Only tritium was observed with certainty in deeper rocks and in the adjacent valley alluvium. Other waste radionuclides were in streamwater and stream sediment, and may have been transported with overland runoff from the surface of the burial site. (USGS)
