Phosphate Mineral Source Evaluation and Zone-of-Influence Estimates for Sediment Contaminant Amendments at the TNX Outfall Delta Operable Unit

摘要

The TNX pilot-scale research facility released processed waste, containing elevated concentrations of several metals and radionuclides into an unlined seepage basin between 1958 and 1980. The contents of this basin have entered the nearby swamp, the TNX Outfall Delta (TNX OD), by subsurface and overland flow. Studies were conducted to evaluate whether sediment amendments could be used to reduce contaminant mobility and bioavailability. Previous studies showed that the addition of a phosphate mineral, apatite, and zero-valent iron, Fe(0), were effective at immobilizing a broad range of contaminants at the site. It is anticipated that the sediment amendments will be broadcast on the ground surface and backfilled into drilled 2 cm diameter x 15 cm deep holes spaced across the contaminated area. The amendments' zone-of-influence of these two application methods was conducted to permit treatment design. The objective of this study was to determine (1) which source of phosphate mineral is most suitable for sediment-contaminant stabilization, and (2) what is the extent of the zone-of-influence of applied apatite and Fe(0).