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.

2.1.2.1  Under direction of the OSC, START conducted a review of various historical records including correspondence, inspections, investigations, photos, media reports, etc., compiled and provided to the OSC by Ms. P. Ameno, an informed local community activist.  The files were reviewed in response to concerns from Ms. Ameno that improper radioactive waste disposal practices were used at the Site during its years of operation as a radioactive research facility and disposal facility.  Review comments were provided to the OSC on 9/15/14.

2.1.2.2  February 2014 validated analytical results related to the second EPA Monitoring Wells sampling event were reviewed.  Organics and inorganics results were conservatively compared against federal and state drinking water standards and EPA regional screening levels and are briefly discussed below.

All Target Compound List (TCL) trace volatile organic compound (TVOC) concentrations were below Maximum Contaminant Levels (MCLs), Pennsylvania Medium Specific Concentrations for Residential-Use Aquifers with TDS < 2500 (MSCs), Regional Screening Levels for tap water (RSLs TR10-6, HQ=0.1) and Contract Required Quantitation Limits (CRQL).  

All TCL semi-volatile organic compounds (SVOC) including 1,4-dioxane were non-detected.  

The total and dissolved metals, mercury and uranium validation report indicated total lead was detected In EPA04 at 5.6 ug/L which slightly exceeded the MSC (5.0 ug/L).  Lead was not detected in the filtered sample.  Manganese was detected In EPA01 at 1,480 and 1,620 ug/L respectively for the total and filtered samples, and in EPA02 at 329 and 317 ug/L.  Manganese concentrations exceeded the MSC (300 ug/L) in both the filtered and unfiltered samples at EPA01 and EPA02.  Arsenic, barium, cobalt, and iron were also detected above the RSLs for tap water.

Alpha spec and gamma spec radionuclide results continue to be reviewed by EPA.

Laboratory data, including radionuclide results, were summarized and included with a summary letter report that was provided to the OSC on 12/23/14.

2.1.2.3  March 2014 validated analytical results related to the EPA/USACE split sampling event in the SLDA were received and reviewed.  Organic and inorganic results are briefly discussed below.

Trace concentrations of TCL TVOCs (e.g. < 2 ug/L) were detected in four of the nine samples collected in the SLDA (a.k.a. three of the eight wells sampled).  Low level or trace detections of 1,1-dichloroethane, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, cis-1,2-dichloroethene, m,p-xylene, and trichloroethene were below MSC and MCL benchmarks.  Trichloroethene (1.5 ug/L, 1.5 ug/L) was the only compound that exceeded the conservative RSL for tap water (0.28 ug/L) in the duplicate sample set collected at MW52.

Only low concentrations of diethylphthalate (2.1 J ug/L, 4.4 J ug/L) were detected in 10L31 and MW14; concentrations that are below benchmarks.  No other SVOCs were detected in the samples.  

There were no metals that exceeded MCLs.  In five of the seven wells sampled for metals, one or more detections exceeded MSC concentrations including (highest concentration, MSC are shown):  cobalt (20.6 ug/L, 11 ug/L), lead (8.8 ug/L, 5 ug/L), manganese (884 ug/L, 300 ug/L), and nickel (164 ug/L, 100 ug/L).  Aluminum, barium, beryllium, iron, were also detected at concentrations that exceeded RSLs for tap water.

Radionuclides, including alpha and gamma spec results, continue to be reviewed by EPA.

Laboratory data are being summarized and will be included with a summary letter report to be provided to the OSC.

2.1.2.4  On 10/26/14, START mobilized to the site area to conduct a groundwater, drinking water and mine outfall sampling event.  On 10/27/14, the OSC and SAO met START on site.  Sampling activities continued through 10/28/14 and demobilization occurred on 10/29/14.  In all, six samples were collected from four of the five EPA monitoring wells plus HW-15 (a non-functioning residential well).  Ten (10) samples including one duplicate pair were collected from nine residential wells where access was granted to EPA by property owners.  One duplicate set of surface water samples was collected from the mine outfall located above Carnahan Run (location 001).  One trip blank, one rinsate blank, and two field blank samples were also collected during this sampling event.  Sampling was conducted in accordance with the approved SAP.

Monitoring well EPA03D was not sampled due to having an insufficient storage and recharge rate.  EPA04 was sampled; however, it too had an insufficient recharge rate and the pumping water level dropped 4.5 feet prior to stabilization (purge rate = 80-100 ml/min).    

Drinking water samples from residential wells were collected from either indoor or outdoor faucets/spigots by START at locations agreed upon between the OSC and home owner.  The surface water duplicate sample was collected directly from the mine outfall located above Carnahan Run. 

The samples were packaged and sent to KAP Technologies, Inc. (organics), ChemTech Consulting (inorganics) and NAREL (rad).  Laboratory space was procured by the EPA Region III Client Services Team (CST).  Samples were analyzed for TCL TVOAs, SVOCs plus 1,4-Dioxane, TAL total and dissolved metals plus mercury and 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). 

2.1.2.5  On 12/10/14 and 12/17/14, respectively, validated organic and inorganic laboratory results related to the 10/27/14 sampling event were received.  START uploaded the data into SCRIBE and provided a draft summary of VOC and SVOC results for drinking water samples, including a sample location map, to the OSC on 12/16/14.