LINE 1 FORMER WASTE WATER IMPOUNDMENT

 

SITE DESCRIPTION

This site consists of the Line 1 Former Wastewater Impoundment and upgradient settling basins.  The Line 1 Former Wastewater Impoundment was formed by damming a portion of the upper reaches of Brush Creek. The primary function of the impoundment was to allow settling of particulate matter from explosives-contaminated wastewater from Line 1 (a former AEC and Army site) before it discharged downstream. This impoundment received large volumes of discharge from 1948 to 1957. The wastes included TNT, coal pile runoff, and condensate from the coal-fired power plant. Fly ash would be added to the impoundment liquid to absorb the explosives and reduce the color. It was estimated that the impoundment was 3.6 acres in size and as large as 7.5 acres (1,300 to 2,400 feet long) during periods of high flow. The embankment was breached after 1957; Brush Creek flowed through the breach and the former impounded area was allowed to re-vegetate naturally.

RI work for the Impoundment area was completed in 1991.

The Army Decision Document was approved in 1995, and the Action Memo was approved in 1996. A contaminated soils IRA was completed during 1997 when 8,270cy of explosives-contaminated soils were excavated from this area. The excavated soils contained greater than 3,900lbs. of explosives. This soil was taken to the Inert Disposal Area (IAAP-020) where it was separated by level of contamination. Approximately 1000cy of higher contaminated soil was placed in Trench 7 and will be treated as required by the ROD. The remainder was placed in a landfill without treatment.

This site has been converted into wetlands. Native plants containing the nitroreductase enzyme are being used to phytoremediate the surface water. Low levels of residual explosives remain in surface water within the impoundment, and they are treated with granular activated carbon prior to discharge into Brush Creek.

The FUSRAP PA identified this area as requiring additional investigation.  In August 2004, FUSRAP conducted a screening survey of this site to determine if radiological contaminates from AEC activites are present in soil.  Preliminary assessments of all screening results indicate no radiological contamination present at this area.  Groundwater contamination was discovered in 2004.

Phase progress will be tracked at this PBC Site, but funding requirements for groundwater will be tracked under Site PBC at Iowa.  Post PBC costs will be covered under Site IAAP-020.

 

CLEANUP STRATEGY

This site is included in the PBC awarded in 2004.  The remedial approach for groundwater at this site, as well as others in the Brush Creek watershed, will be assessed in the FS.  At present, it is presumed that localized areas of groundwater contamination will be remediated.  Surface water management will continue.

STATUS

RRSE RATING: High

CONTAMINANTS: Explosives

MEDIA OF CONCERN: Soil, Surface Water, Sediment, Groundwater

COMPLETED IRP PHASE: PA/SI, IRA, RI/FS, RA(C)

CURRENT IRP PHASE: RA(O)

FUTURE IRP PHASE: None