The United States Army Corps of Engineers (USACE) conducted an investigation of the radiological contamination at the SLDA site under the Formerly Utilized Sites Remedial Action Program (FUSRAP) consistent with guidance issued by the EPA.  The results of these investigations are presented in the RI report (USACE 2005).  To support preparation of the RI report, USACE conducted a number of field investigations from August 2003 through January 2004 to determine the nature and extent of radioactive contamination at the SLDA Site.  Prior to this fieldwork, in-depth historical record searches and analyses were conducted, and detailed interviews performed with individuals familiar with disposal operations at the SLDA.  In conducting the RI, USACE collected samples from surface and subsurface soils, trench waste, the five water-bearing geologic units, sediment, surface water, and groundwater seeps.  This sampling program indicated that surface water and sediment in Carnahan Run were uncontaminated, while low levels of radioactive contamination were present at on-site locations in Dry Run and groundwater seeps in the upper trench area.  Groundwater at the SLDA Site, outside of perched areas within the trenches, did not appear to be contaminated, other than some localized areas in the upper trench area in the upper shallow bedrock water-bearing zone down gradient of disposal trenches 1 and 2.  Some low levels of contamination were identified at this location, which may have been associated with the radioactive wastes in these two trenches.  In summary, the contaminated media identified at the SLDA Site were the trench wastes, surface and subsurface soils, and sediment in Dry Run. 

Residents from both the Community of Kiskimere and its adjacent neighboring towns (Vandergrift and Leechburg), have contacted EPA and expressed concern that their well water may have been and may currently be contaminated by leachate from the disposed materials at the SLDA and Parks clean-up Sites. During late August 2011, EPA conducted a focused Site Investigation to determine if residents were being exposed to radiological and chemical contaminants related to the nearby sites.  Samples were collected from residential wells, surface water and sediments and analyzed for gross alpha/beta, radium 226/228, gamma spec, metals, mercury, uranium, and volatile organic compounds (VOCs).  The results indicated that the radionuclides, metals, and organic contaminants in the private wells and environmental samples were within a normal range of background concentrations found in the Parks Township area.  Although sample results did not show levels of contamination that would cause a health concern, EPA determined that additional information was needed to further characterize the groundwater.

During September 2013, in accordance with the approved SAP, the OSC and START collected sediment and groundwater samples from the area of investigation.  Fifty-four (54) sediment samples were collected from the Kiskiminetas River to assess metals and radionuclide constituents that could be attributed to an offsite release from the SLDA.  Four areas of the river were sampled and include: 1) background locations located upstream from the former NUMEC nuclear facility in Apollo, PA; 2) upstream from the Site and Carnahan Run; 3) across from the Site; and 4) downstream near the Hyde Park footbridge in Leechburg, PA.  As samples were collected, the location was marked with a numbered buoy and the sample labeled and placed in a cooler.  After all the samples in an area were collected, GPS information was collected using a Trimble ProXH GPS receiver.  The buoy was removed from the river after the GPS coordinates were collected.  Sediment samples were shipped to off-site labs procured through the EPA CST.  Off-site laboratory analyses included TAL metals, mercury, uranium, and radionuclide analyses including Alpha Spec AM-241, Pu-238/239/240/242, Th-230/232, U-234/235/238 and Gamma Spec (incl: Co-60, Cs-137, Th-234, Bi-212, Pb-212, Pb-214, K-40, Ra-226, Ra-228). 

During September 2013, the OSC and START collected samples from the five EPA monitoring wells that were installed during July 2013.  A sample was also collected from the unused home well (HW15) that was inspected earlier.  Static water level measurements were collected prior to sampling.  Low Flow procedures were used to collect the samples at all but EPA03D where a bailer was used due to low volume and recharge rate.  Samples for metals analysis were field filtered and preserved by START.  A total of seven (7) samples were collected, including a duplicate sample. Requisite QA/QC samples (field blank, trip blank, rinsate blank) were collected.  The samples were packaged and sent laboratories procured through EPA.  The samples were analyzed for TCL TVOAs, 1,4-Dioxane, SVOCs, TAL metals, mercury, uranium, and radionuclide analyses including Alpha Spec AM-241, Pu-238/239/240/242, Th-230/232, U-234/235/238 and Gamma Spec (incl: Co-60, Cs-137, Th-234, Bi-212, Pb-212, Pb-214, K-40, Ra-226, Ra-228).  Validated data from this sampling event was received in November 2013 – March 2014.  The data was analyzed and a trip report prepared for the EPA OSC.