New York State Department of Environmental Conservation 93 Main Street Site

Posted on June 16, 2015

Client: New York State Department of Environmental Conservation
Location: 93 Main Street Site

Major Components

  • Remedial Design Work Plan
  • Pre-Design Investigation Report
  • Remedial Design

Project Description

Introduction

The 93 Main Street Site was a commercial pest control/extermination operation from the 1950’s to 1980’s that used Chlordane, Silvex, Aldrin, Dieldrin, DDT, 2,4,5-T and 2,4-D among other currently banned pesticides and herbicides. It is a 1-acre Class 2 Inactive Hazardous Waste Disposal site located in the City of Binghamton, New York.

D&B Engineers and Architects, P.C. was retained by the New York State Department of Environmental Conservation (NYSDEC) to undertake pre-design investigation activities; a comprehensive remedial design, including the preparation of remedial plans, specifications and contract documents; as well as provide pre-award services for the 93 Main Street Site.

Site Background

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  • The 93 Main Street Site was used from the 1950’s to 1980’s by the McMahon Brothers Pest Control Company as a pesticide and herbicide storage and handling facility.
  • In 1989, the New York State Department of Environmental Conservation (NYSDEC) investigated complaints that pesticide application equipment and drums containing pesticides were being stored at the site. A drum containing the herbicides Silvex and 2,4 dichlorophenol, as well as herbicide spraying equipment, were discovered on the property.
  • In 1995, a Phase 2 Environmental Site Assessment was conducted on the property. Analytical results of soil samples collected at the facility revealed elevated levels of banned herbicides and pesticides, including 2,4,5 trichlorophenol at 12,000 ug/kg, 2,4-dichlorophenol at 4,030 ug/kg and chlordane at 15,000 ug/kg. Aldrin, Dieldrin and DDT were subsequently detected at 46,000 ug/kg, 97,000 ug/kg and 69,000 ug/kg, respectively.
  • In 1995, the City of Binghamton entered into a Voluntary Cleanup Agreement (VCA) with the NYSDEC to perform a limited investigation of the site. The results of this investigation revealed elevated concentrations of pesticides and herbicides such as chlordane, aldrin, dieldrin, and 2,4,5-trichlorophenol in groundwater and soil at the site. Most of the pesticide/herbicide concentrations significantly exceeded NYSDEC groundwater standards. The presence of these pesticides or herbicides at elevated levels indicated a threat to the area’s Sole Source Aquifer and was the basis for the site being designed a Class 2 on NYSDEC’s Registry of Inactive Hazardous Waste Disposal Sites.
  • In October 1998, a Remedial Investigation/Feasibility Study defined and evaluated the nature and extent of contamination resulting from previous activities at the site.
  • The Record of Decision (ROD) was published in March 2000, and recommended that a remedial design program be performed to verify the components of the conceptual design and provide the details necessary for the construction, operation, maintenance and monitoring of the remedial program. The program included:
    • batch and/or pilot testing of oxidizing agents;
    • excavation of the area surrounding an on-site dry well to a depth of 6 feet and collection of confirmatory samples from the walls and floor of the excavation to ensure that all contaminated soil above remedial objectives was removed;
    • treatment of contaminated soil on-site by chemical oxidation and/or disposal of off-site, as appropriate;
    • backfill of the excavation with suitable fill material determined to be free of contamination;
    • treatment of the remaining areas of concern with oxidizing agents;
    • construction/installation of groundwater extraction wells to create a zone of hydraulic containment large enough to collect any leachate produced during treatment of contaminated soil; and
    • design and implementation of a long-term monitoring program for groundwater and leachate.
  • In 2004, D&B was issued a work assignment to provide a remedial design plan, perform a pre-design study, prepare plans and specifications, and provide pre-award services.
  • In 2007, the ROD was amended to mandate excavation and off-site disposal of approximately 1,059 cubic yards of contaminated soil. Localized groundwater contamination was treated on-site by a temporary treatment system as part of the dewatering process during soil excavation.

Pre-Design Investigation

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A pre-design study was performed prior to preparation of the remedial design to provide site-specific information for the design of the remediation system, including an aquifer pumping test, and a chemical oxidation soil treatment system pilot test. The pre-design field activities consisted of soil borings, monitoring well installation, subsurface soil vapor sampling, water level monitoring, groundwater and soil sampling and analysis, and a bench scale treatability study to determine the design parameters for the site. The bench scale groundwater treatability study evaluated chemical oxidation or carbon filtration for groundwater treatment and the viability of chemical oxidation to treat the soil.

D&B awarded a contract to Blue Lightning Underground Enterprises (BLUE) to conduct a 35 day chemical oxidation pilot test at the site as a means of treating pesticide-contaminated soil. BLUE installed four gas injection points, one soil vapor extraction well, and three vapor monitoring points in the designated pilot test area. Soil samples were collected for baseline analysis during the drilling activities. Ozone injection and soil vapor extraction operation began in November 2005, and continued for 35 days.

In January 2006, 38 days after completion of ozone injection, post-injection soil sampling was conducted. The analytical results were compared against the baseline soil sample results. Several of the post-test soil sample analytical results indicated an increase in pesticide compounds, resulting in an overall mass increase of contaminants from 1.5 lbs to 3.7 lbs. This increase was attributed to the influence of contamination outside the pilot test area, incomplete oxidation of absorbed contamination or different soil sampling depths. Based on the results of the total mass remaining in the test area, D&B concluded that chemical oxidation with ozone was not an effective remediation technology for the site. Based on the conclusions of this pilot test program, the ROD was amended in July 2007 to include excavation and off-site disposal of approximately 1,100 cubic yards of soil followed by the placement of certified clean backfill along with restoration of the site.93main3

In the Autumn of 2008, D&B conducted supplemental investigation activities at the site in support of the remedial design mandated by the amended ROD. In particular, soil sampling was conducted to confirm the limits of the excavation areas required to remove the contaminated soil and confirm that the cleanup objectives had been achieved. Soil samples were taken within each proposed excavation area, but also at discrete distances at the perimeter of each excavation area. One hundred-seventy soil samples were collected at the site over the course of three separate sampling events and were submitted for laboratory analysis for Target Compound List (TCL) pesticides in accordance with USEPA Method 8081A. In addition, samples collected near Excavation Area 2 were also analyzed for volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs) due to elevated PID readings and a petroleum-like odor during sampling. Based on the results of the soil sampling, two of the three excavation areas were expanded and it was discovered that only soil excavated from one of the three areas is considered hazardous when disposed of off-site.

Remedial Design

Contract Documents, consisting of design drawings and specifications, were prepared for the purpose of competitively bidding the remedial construction component of the project in conformance with the amended ROD. In addition, a groundwater monitoring program designed to document the attenuation of residual groundwater contamination was implemented. Lastly, a site management plan was developed that includes the implementation of a post-excavation groundwater monitoring program to assess the attenuation of residual groundwater contamination. In addition, D&B was retained to provide pre award services in conjunction with the competitive bidding of the remedial construction project. These services included assisting at a pre-bid conference, preparing written responses to questions from the conference, bid review and attendance at a public meeting.

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