In August 2014, the last known occupant of the residence at 209 Shinkle Chapel Road contacted the Kentucky Department for Environmental Protection (KDEP) with a concern about an unknown white powdery substance at the Site. KDEP reported that the former occupant bred dogs at the Site and that the females were found to be sterile while others suffered from tumors. The former occupant was concerned about potential exposure to her family members while they lived at the property.
In September 2014, KDEP performed an initial visual investigation at the Site. They confirmed an area where the white substance was located in an area devoid of vegetation and approximately 30 feet in diameter. Samples were collected in October 2014, and analysis of the samples collected from this area revealed total arsenic at levels up to 525,000 milligrams/kilogram (mg/kg). The Toxicity Characteristic Leaching Procedure (TCLP) was performed on the sample with the highest total arsenic level and the result came back as 618 milligrams/liter (mg/L) leachable arsenic. Additional investigation and sampling in October 2014 documented that the arsenic contamination had migrated downhill a distance of approximately 120 feet to the north and west of the source area.
On November 14, 2104, the KDEP Superfund Branch formally requested that the U.S. EPA conduct a Removal Site Evaluation (RSE) at the Site.
On March 24, 2015, the Region 4 Superfund Technical Assessment and Response Team (START) contractor mobilized to the Site to collect samples. The purpose was to confirm the 2014 KDEP findings and to explore the potential for additional migration pathways at the Site. Also, a subset of samples were run for arsenic speciation in an attempt to identify the specific arsenic compound at the Site. The sample collected from the source area was analyzed for total arsenic and the analysis revealed the concentration of arsenic to be 747,000 mg/kg. The arsenic speciation determined that the arsenic is an arsenite compound (As+3).
Based on this information, the On-Scene Coordinator (OSC) completed the RSE under 40 CFR Section 300.410, and concluded that the Site meets the National Contingency Plan (NCP) criteria for a time-critical removal action.
On October 20 and 21, 2015, START’s Tetra Tech and OTIE contractors conducted the following sampling activities at the Site:
•X-ray fluorescence (XRF) soil and sediment screening
•Vacuum sampling and air sampling from within the interior of the single family residence
•Surface and subsurface soil sampling at various locations on-site
•Surface sediment sampling from a dry creek bed located directly down-gradient of the source area
All samples collected from the inside of the residence were analyzed for the presence of arsenic and were found to be non-detect. However, arsenic was detected in sediments along the entire 1,800-foot segment of the dry creek bed that was surveyed in concentrations ranging from 130 mg/kg to 4,200 mg/kg. Approximately 700 feet of the dry creek leading to the confluence with Little No Creek remains uncharacterized due to access issues encountered during the October 2015 sampling investigation.
In February 2016, the OSC directed the OTIE START contractor to collect samples of surface water runoff in the stream beds which drain the Site to the north and south. The surface water sample in the northern drainage feature was revealed to contain 0.507 milligrams per liter (mg/l) of arsenic. This exceeds the Water Quality Criteria (WQC) adopted by the Commonwealth of Kentucky of 0.340 mg/l, based on acute toxicity to aquatic species. The surface water feature in the southern drainage feature was discovered to be non-detect for arsenic.
On June 28, 2016, the EPA Region 4 Superfund Division Director signed an Action Memorandum for the Wiley Property Site, authorizing a project ceiling of $1,850,000 for removal of arsenic contamination. The proposed activities are as follows:
1.Remove stockpiled waste materials and dispose of at an approved hazardous waste management facility.
2.Excavate soils on the residential property to an approximate depth of 1.5 feet BLS where arsenic concentrations at the surface are at 68 mg/kg or above and dispose of at a permitted off-site facility.
3.Excavate soils on the non-residential property to an approximate depth of 1.5 feet BLS where arsenic concentrations at the surface are at 420 mg/kg or above and dispose of at a permitted off-site facility.
4.Excavate sediments along an 800-foot segment of the dry creek bed draining the Site along its northern boundary. Excavation will be carried out along this segment until a residual arsenic concentration of 50 mg/kg and compliance with the WQC of 0.340 mg/l for acute toxicity is achieved.
5.Backfill excavated areas on the residential property with clean soil to re-establish vegetative cover and re-grade the areas to promote positive drainage
6.Re-establish vegetative cover on the non-residential property and re-grade the area to promote positive drainage.
