H-Area Seepage Basins groundwater monitoring report

During fourth quarter 1992, the groundwater at the H-Area Seepage Basins (HASB) was monitored in compliance with South Carolina Hazardous Waste Management Regulations, R61-79.265, Subpart F. Samples were collected from 130 wells that monitor the three separate hydrostratigraphic units that make up the uppermost aquifer beneath the HASB. A detailed description of the uppermost aquifer is included in the Resource Conservation and Recovery Act Part B Post-Closure Care Permit Application for the H-Area Hazardous Waste Management Facility submitted to the South Carolina Department of Health and Environmental Control in December 1990. Historically, as well as currently, tritium, nitrate, total alpha-emitting radium, gross alpha, and mercury have been the primary constituents observed above final Primary Drinking Water Standards (PDWS) in groundwater at the HASB. Isoconcentration/isoactivity maps included in this report indicate both the concentration/activity and extent of the primary contaminants in each of the three hydrostratigraphic units during first and fourth quarter 1992. Water-level maps indicate that the groundwater flow rates and directions at the HASB have remained relatively constant since the basins ceased to be active in 1988