The Precision National Plating Site is located at 198 Ackerly Road, Clarks Summit, Pennsylvania, which is approximately 10 miles north of Scranton, Pennsylvania. The property measures 46 acres, approximately five acres of which were used for site operations and the remainder of which are undeveloped and largely wooded. A 45,000 square foot operations building was the principal structure on the site.
The site began operation as a chromium electroplating facility for locomotive crankshafts in 1956. This operation continued when Precision bought the facility in 1971. Precision operated an industrial component reconditioning facility on site from 1971 until 1999.
Site operations ceased in April 1999. With PADEP and USEPA oversight, the former plating building was demolished in the Fall of 2000.
EPA approved a Remedial Action Plan, submitted on behalf of Precision National Plating by the Retec Group in September of 2005. The Plan details procedures for use of calcium polysulfide to reduce the hexavalent chromium in the soils and groundwater to trivalent chromium, a less toxic form of chromium, which will precipitate and remain in the soil/bedrock matrix.
In July 2006, Precision injected calcium polysulfide into source areas at the site. The goal of the treatment was to reduce hexavalent chromium levels in soil to below 60 mg/Kg, and hexavalent chromium levels in Ackerly Creek to below 11 ug/L.
In March 2007, Precision began excavation of the basement of the former facility. The purpose of the removal was to mitigate impacts by potentially contaminated soils beneath the basement. Any visually contaminated soil and concrete unearthed during the excavation was taken to an appropriate disposal facility.
Further site investigation activities were performed in the Fall of 2007 and February/March 2008. The soil boring, rock coring and groundwater sampling activities completed in October 2007 and March 2008 confirmed that residual contaminant sources remain at the Site in the weathered rock and shallow competent bedrock (18 - 30 feet below the ground surface).
In August 2008, Precision began using calcium polysulfide in-situ chemical injections to treat these residual areas of contamination in the shallow bedrock. Hexavalent chromium levels have dropped in Ackerly Creek due to chemical injection treatments in July 2006 and the basement excavation in March 2007, and subsequent injection activities beginning in August 2008 and continuing through December 2011, however they still remain above the target ecological goal of 11 ug/L.
Precision contractors collected samples from groundwater wells throughout the site this week prior to the beginning of injection activities. Samples will be analyzed for total and hexavelent chromium concentrations to document current site conditions.
Maintenance was conducted on the injection system to prepare for injection activities. All flow meters within the injection manifold were replaced, lines were cleared and tested, air compressors were tested, and wellheads were cleaned. Air monitoring equipment was tested at the lagoon and along Arch Avenue. Communication issues were identified with the unit on Arch Avenue, but were corrected on Thursday. Both air monitoring units are now communicating properly with the system trailer.
Injections began on Thursday, September 6th, 2012. Approximately 1,000 gallons of 1% calcium polysulfide solution was injected this week. Injection occurred in four shallow bedrock points surrounding SB-15 in the area of the former building foundation on the Precision property. Sampling activities over the summer identified some rebounding of hexavalent chromium concentrations in SB-15.
Prior to, and during injection activities, hourly air monitoring readings were taken with a Jerome hydrogen sulfide meter along the perimeter of the site fence and along Arch Avenue. No concentrations of hydrogen sulfide were documented during injection activities above the instrument detection limit of 3 ug/m3.
Precision contractors will conduct packer testing on six monitoring wells. Packer testing consists of isolating specific fractures within a well identified during a geophysical investigation. Each fracture within these wells will be sampled for total and hexavalent chromium concentrations, and be tested to determine the amount of groundwater flow the fracture is capable of. Due to equipment issues, packer testing has been postponed and is expected to begin the week of September 17th.
The current round of injection activities began on September 6th, 2012. Injection activities are expected to continue through November 2012, injecting calcium polysulfide solution into overburden and shallow bedrock aquifers. During injection activities, air monitoring will be conducted for concentrations of hydrogen sulfide by two fixed point monitoring stations 24 hours a day at the lagoon and on Arch Avenue. In addition, during working hours, Precision contractor personnel will conduct hourly air monitoring using hand held instruments at predesignated locations.
During injection activities, Precision contractors will sample potable wells, currently in-use and directly adjacent to the site, once every two weeks for hexavalent chromium, total chromium, sulfides, sulfates, and pH. Additional groundwater and surface water locations will be monitored for pH, dissolved oxygen, oxidation-reduction potential, specific conductance, and concentrations of sulfide and sulfates on varying schedules. Additional details regarding the injection activities are documented in the Response Action Plan. EPA will have personnel onsite to document monitoring and progress throughout the injection activities.
Semi-annual groundwater monitoring activities will be conducted in October 2012. Select wells from the overburden, shallow, intermediate, and deep bedrock zones will be sampled by Precision contractors for hexavalent and total chromium analysis. Surface water samples from Ackerly Creek and the drainage swale along Ackerly Road will be collected and split by EPA and Precision contractors.
EPA is currently finalizing a web based data viewing tool to better provide access and easier understanding to the public of sampling activities and progress at the site. This is expected to be released to the public this Fall. EPA is currently scheduling a time with Glenburn Township to release the data viewer and provide a demonstration session to the public.