| Site Type: Long Term/National Priorities List (NPL) |
SILRESIM CHEMICAL CORP.
Map this site in Cleanups in My Community
| Lowell,  Massachusetts|
| Middlesex County
| Street Address: ||86 TANNER ST |
| Zip Code: || 01853 |
| Congressional |
| EPA ID #: ||MAD000192393 |
| Site ID #: ||0100326 |
| Site Aliases: |
| Site Responsibility: ||Federal, Potentially Responsible Parties |
| NPL LISTING HISTORY |
| Proposed Date ||07/23/1982|
| Final Date ||09/08/1983 |
The Silresim Chemical Corporation Site is located at 86 Tanner Street and consists of the 4.5-acre Silresim property and soil and groundwater contamination that extends to other nearby properties. Starting in 1971, Silresim began reclaiming a variety of chemical wastes, waste oil, solvents, and sludges containing heavy metals. In 1977, Silresim declared bankruptcy and abandoned the property, leaving behind 30,000 decaying drums and several large storage tanks. The State began to clean up the Site in 1978. The Site is located in an industrial area approximately one mile south of the central business district of Lowell and several hundred feet from the nearest residential area. Approximately 10,000 people live within 1 mile, and an estimated 24,000 people live within 3 miles of the Site. Groundwater flows generally to the northwest towards River Meadow Brook, which drains into the Concord River and then into the Merrimack River.
Threats and Contaminants
Groundwater is contaminated with volatile organic compounds (VOCs), semi-volatile organic compounds, pesticides, polychlorinated biphenyls (PCBs), and heavy metals. Soil is contaminated with VOCs, semi-volatile organic compounds, pesticides, and PCBs. Low levels of dioxin also are present in the soil. Accidental ingestion or contact with contaminated soils and groundwater could pose a health risk.
The potentially responsible parties and EPA conducted numerous investigations of the extent of contamination - the results of which were subsequently utilized in the preparation of a Remedial Investigation (RI) report. Activities described in the RI Report include groundwater, surface water and sediments sampling; monitoring; well installation; and sampling vents for air contamination. Surface soil testing and sampling beneath the interim clay cap and outside the fence determined the extent of soil contamination. Based on the results of the RI, an assessment of various clean-up technologies was completed; these evaluations are contained in the Feasibility Study (FS). Based on the results of the FS, a final clean-up plan (the “remedy”) was selected in a September 1991 Record of Decision (ROD). Subsequent to the ROD, revised soil and groundwater clean-up goals were adopted in a 2003 Explanation of Significant Differences (ESD). The remedy was further modified via a 2008 ESD, described in more detail in other sections below.
In general, the 1991 ROD describes a comprehensive remedy for the site, once in which both a Management of Migration remedy as well as Source Control remedy were selected. In regard to the Management of Migration, a groundwater pump and treat system was selected as the preferred technology. In regard to Source Control, soil-vapor extraction (SVE) was selected to treat VOC-contaminated soils. The ROD also specified that other non-VOC contaminants in soil be excavated, stabilized and disposed of on site under a low permeability cap.
Response Action Status
|Interim Actions ||Prior to the Site’s listing on the NPL, the State removed all chemical wastes in above-ground storage containers, fenced a portion of the Site, and dismantled buildings. In 1983, EPA monitored the air and sampled soils, and found contamination both on and off the Silresim property. In 1984, EPA raised the height of the fence and covered highly-contaminated areas with gravel and an interim clay cap. Subsequent sampling revealed an additional area of soil contamination that EPA enclosed. In 1986, the EPA discovered dioxin; the fence was relocated to prevent public access, and a temporary gravel cover was placed over the dioxin-contaminated soil. |
|Management of Migration ||The groundwater extraction and treatment remedy described in the 1991 ROD included metals removal, air stripping, and vapor treatment prior to discharge to the City sewer system. The groundwater extraction system was also intended to drawdown the groundwater level at the Site to facilitate SVE activities. Construction of the groundwater treatment facility began in mid-1994 and has been in operation since November 1995. The Massachusetts Department of Environmental Protection (MassDEP) accepted transfer of the groundwater treatment plant and its operation beginning in September 2007. |
|Source Control ||Soil Vapor Extraction was selected as the Source Control remedy in the 1991 ROD. In March 1997, EPA completed an SVE pilot test. Following completion of the pilot test, the first phase of the SVE system was implemented over a portion of the Site and operated from October 1998 to December 1999. Although the SVE system removed approximately 12 tons of VOCs, EPA concluded that the SVE system would not be able to reach clean-up goals due to difficult site conditions such as high soil moisture and low soil permeability. Operation of the SVE system was terminated.|
As a result of the inability of traditional SVE to effectively reduce the VOC source, thermal-enhanced remedial technologies were evaluated. From October 2002 through January 2003, EPA conducted an electrical resistance heating (ERH) pilot test. ERH is an in-situ thermal remediation technology that uses electricity to heat the subsurface thereby liberating more VOCs. The results of the ERH pilot test indicate that a substantial reduction in total VOCs were attainable and its effectiveness is not limited by the relatively high groundwater table. In 2008, EPA memorialized its decision in an ESD to implement a thermal treatment remedy (i.e., ERH) and in 2010 began ERH construction. See added details below
Off-site soil excavation activities began in late September 2004 and were completed in November 2004. Soil on properties adjacent to the Silresim property that was contaminated as result of Silresim operations were excavated and placed under an interim cap on the Silresim property. A Remedial Design for the final protective cover was completed in 2008. In addition, based in part on the success of the 2003 Pilot Test for ERH, the Army Corps of Engineers completed a Remedial Design for the thermal treatment of up to 60,000 cubic yards of contaminated soil. Construction of the remaining remedy components, the final capping and thermal treatment of soil, were funded via the American Recovery and Reinvestment Act (ARRA).
|Enforcement Highlights||EPA negotiated with a group of potentially responsible parties to conduct studies to determine the nature and extent of contamination and develop alternative cleanup technologies. A Consent Decree was executed between EPA and potentially responsible parties in early 1993 through which provided funding for a portion of the remedial actions. |
Initial actions to fence the Site and cap or cover areas of contamination have reduced the potential for accidental exposure and the further migration of contamination from the Site. The interim cap was further improved during construction of the groundwater treatment facility and the Site has been secured since construction activity began in mid-1994. These actions have eliminated the immediate threats posed by the Site while final cleanup activities are underway. The groundwater treatment facility has been operating since November 1995.
Based on the reclassification of the groundwater at the Site, the collection of additional data, and current EPA risk assessment guidance, clean-up goals were modified in 2003 and again in 2008 via an Explanation of Significant Differences (ESD). The 2008 ESD can be viewed below via the link under “Links to Other Site Information” or at the Pollard Memorial Library or the EPA New England Record Center. Remedial Designs (RDs) for implementation of thermally-enhanced soil vapor extraction using Electrical Resistive Heating (ERH) technology and construction of the Final Cap were also completed in 2008. In April 2009, it was announced that these two final phases of cleanup would be funded via the American Recovery and Reinvestment Act (ARRA). In 2010, the Final Cover was constructed and ERH construction began. The site achieved a "Construction Completion" status in 2010 and all final site restoration activities following the completion of the ERH remedy were completed in 2012.
Current Site Status
The third Five-Year Review for the Site was completed in September 2009 and is available for review at the Lowell public library and in the EPA Record Center in Boston. The purpose of a Five-Year Review is to determine whether the cleanup action at a site is protective of human health and the environment. EPA requires a review no less than every five years at sites where any hazardous substances or pollutants remain after implementation of the cleanup action.
The main component of the cleanup to be completed is enhanced soil vapor extraction using electrical resistive heating (ERH). ERH utilizes electrical current passed through soil and groundwater to heat the subsurface which, in turn, releases more organic vapors. The vapors are then collected and treated. The second component of the final remedy is the construction of the final cap over a portion of the Silresim property. Improvements to the existing (interim) cap include increasing the thickness of the existing separation layer, the inclusion of a high-visibility "marker" layer, and the regrading of the rear portion of the Silresim property to support future redevelopment.
EPA issued a Remedial Action Statement of Work to Nobis Engineering, Inc., one of EPA's Remedial Action Contractors, for this $19 million project. In March 2010, Nobis awarded subcontracts for both the final cap construction and electrical resistive heating (ERH) components of the remedy. By October 2010, EPA completed substantial construction of the Final Cap. The cap improvements include increasing the thickness of the separation layer (from 14 to 48 inches), provide a visual demarcation layer, and “levels” the site so as not to preclude site redevelopment. As part of the ERH construction, EPA contractors installed 144 heater electrodes, 77 extraction wells, 55 temperature monitoring points, 8 pressure monitoring points, 48 vapor extraction wells, and 34 monitoring wells. Other construction activities included the mobilization of equipment such as the thermal oxidizer and the construction of above ground liquid and vapor phase plumbing (see pictures below). By July 2011, the ERH system was completed and operational. A Preliminary Close-Out Report was prepared (August 2011) thus documenting construction completion of all planned remedial components. The ERH system operated until February 2012 and was subsequently dismantled. Approximately 50,000 pounds of contaminants were removed during the ERH remedy. As of March 2013, the majority of site restoration activities (fence removal, top soil placement, drainage improvements) have been completed with only few "punch list" items to complete in the Spring 2013.
Proposed ERH Treatment zones.
Electrical Resistive Heating (ERH) Piping
Thermal Oxidizer for ERH Remedial Action
Links to Other Site Information
Maps and Photos:
Newsletters & Press Releases:
Federal Register Notices:
Reports and Studies:
|Administrative Record Index, Record of Decision (ROD), Operable Unit 01, September 19, 1991 (1,735 KB)   |
|Administrative Record Index, Explanation of Significant Differences (ESD), Operable Unit 01, September 1, 2003 (124KB)   |
|Administrative Record Index, Explanation of Significant Differences (ESD) Operable Unit 01, September 1, 2008 (601 KB)   |
Pollard Memorial Library, 401 Merrimack Street, Lowell, MA 01850
OSRR Records and Information Center, 1st Floor, 5 Post Office Square, Suite 100 (HSC), Boston, MA 02109-3912 (617) 918-1440
|EPA Remedial Project Manager: ||Daniel Keefe |
|Address: ||US Environmental Protection Agency|
5 Post Office Square, Suite 100
Mail Code OSRR07-1
Boston, MA 02109-1367
|Phone #: ||617-918-1327 |
|E-Mail Address: ||firstname.lastname@example.org |
|EPA Community Involvement Coordinator: ||Pamela Harting-Barrat |
|Address: ||US Environmental Protection Agency|
5 Post Office Square, Suite 100
Mail Code: ORA20-1
Boston, MA 02109-3912
|Phone #: ||617-918-1318 |
|E-Mail Address: ||email@example.com |
|State Agency Contact: ||Janet Waldron |
|Address: ||1 Winter Street|
Boston, MA 02108
|Phone #: ||617-556-1156 |
|E-Mail Address: ||firstname.lastname@example.org |