You may be surprised to know that Wellesley College has been conducting a number of studies and clean-up activities at the former Henry Wood's Sons Paint Factory property since the 1970s. The former paint factory property borders the western portion of the college's campus on the eastern shore of Paintshop Pond and south of Route 135. Although we've been doing a lot of work at the property and in the surrounding wetlands and water bodies, we may not have done as much communication with people who may be interested. We think you should know what has been going on, the results of these studies, and what work is planned.
(Click to view the June 1999 Information Sheet)
(Click to view the May 1998 Information Sheet)
In the mid-1970's, the DEP informed the College of the presence of high levels of metals in paint pigments found in the soil of the paint factory site, which has been fenced and access restricted. Although the College did not cause the problem, as the owner of the property we have taken full responsibility for resolving it. This update provides information on the alternatives that the College has been considering for cleaning up soils and sediments at the site. Future updates will address alternatives for cleaning up groundwater and sediments in Lake Waban. The site area consists of some 24 acres of land. It includes the uplands - where the factory, formerly used for the manufacture of paint pigments, was located - as well as adjacent wetlands and bodies of water (Paintshop Pond, Waban Brook, Lake Waban). Its boundaries include: Route 135 to the north; the western shoreline of Paintshop Pond to the west; the walking path around the northern wetlands to the east; and the wetlands of Lake Waban, as well as the upland areas south of Waban Brook and Paintshop Pond to the south.
All monitoring and cleanup operations are subject to the Massachusetts Contingency Plan (MCP), administered by the DEP. The MCP outlines requirements for the investigation and cleanup of contaminated sites. During the course of more than two decades, we have worked hard to monitor and test the factory site and adjacent areas, taking and analyzing more than 6,000 samples of soil, sediments, groundwater and surface water. Wellesley College has also undertaken extensive cleanup and prevention efforts. These include the excavation and removal of 3,600 tons of paint pigment in 1991, thus eliminating what had been one of the largest sources of contamination at the paint factory site. Other important steps include:
After carefully investigating the type and extent of contamination at the site, assessments of potential risks to human health and the environment were performed. These results, discussed in separate updates, were used in the current Phase III study. Under Phase III of the MCP, the College has been evaluating possible clean up alternatives that will mitigate the risk from soils and sediments at the site, including:
After an extensive evaluation of the technologies and alternatives described on page two, the College has developed a proposed plan to clean up contaminated soils and sediments. As part of this plan, the College has secured capital project funding from the Massachusetts Higher Education Finance Authority for a "beneficial reuse" such as the creation of athletic fields. The proposed cleanup program involves excavating pigment and contaminated soil from the wetlands sediment from Paintshop Pond and Waban Brook, and pigment and soils from the uplands, and placing these materials in lined containment cells that fully isolate the material. The College would then restore the wetlands with clean soils, providing for re-vegetation of the area with a variety of plants. We would also reopen Paintshop Pond. Taking this action would enable the site to be reused.
The proposed containment cells would be built using two layers of synthetic membrane materials that would line the walls and bottom of the containment cells. The contaminated materials would then be placed in these cells and a second set of synthetic liners placed over the contaminated materials. Up to two feet of soil would be placed over the liners and the soils would be seeded. All areas outside these cells would also be filled with clean soils and planted with a variety of trees and shrubbery. Once cleaned, these areas would be reused. This recommended plan is later identified as Alternative #2 - Excavation and On-site Encapsulation - in the section titled "Alternatives We Considered."
Various technologies are available to address the paint pigment and contaminated soils at the former paint factory site, and the sediments from Paintshop Pond.
In this process, plants are used to absorb contaminants. Absorption takes place through the plants' roots structures, stems and bodies. Once the plants have fully grown, they are harvested, and the contaminants they contained are removed and disposed of as hazardous waste.
This process involves the in-place removal of contaminants from the soil, using water or solvents. The liquids used to flush the soil must be recovered to capture the contaminants. This requires the construction of a groundwater treatment system to collect the washwater. Once the contaminants have been removed, the wash water must be treated further before it can be discharged through the municipal sewer system.
This process involves "washing", in treatment containers, contaminated soil with acid-based or solvent washwater. Soil washing does not detoxify or significantly alter the contaminants, but does transfer the contaminants from a solid to a liquid state, making them easier to treat or dispose of. The contaminated washwater must then be treated on-site, and subsequently sent to a wastewater facility or shipped directly to a wastewater treatment facility.
This process is used to chemically convert the metal contaminants to non-hazardous or less toxic compounds that are more stable.
This process involves putting into the soil chemicals that cause the metal contaminants to be immobilized, thus preventing their movement.
In this process, an electrical current is used to melt the soil and turn it into a glass-like substance. The melting process immobilizes the metal contaminants.
Technologies were considered to address contamination in place (referred to as in-situ) or above ground in a central location (ex-situ).Each of the technologies was evaluated as a "stand-alone" solution, or as part of an integrated approach involving a mix of technologies.
Technologies were initially evaluated, using two criteria:
1. Technical Feasibility; and
2. The Viability of Implementation.
Technical feasibility examines the ability and effectiveness of the technologies to address the site's contamination problem, and looks at how successful the technology has been in the cleanup of other sites. The viability of implementation refers to whether there are people available who are experienced in implementing a particular technology.
Once these technologies were evaluated, the in-place technologies were eliminated because of existing site conditions, which include buried pigments at various depths throughout the property and buried construction and demolition debris which make these technologies infeasible. In addition, toxic concentrations of metals in the pigments and soils prohibit certain treatment processes.
ALTERNATIVES WE CONSIDERED
After screening the technologies, several alternatives were formed. Each alternative was evaluated, based on:
(1) how feasible its implementation would be under the current site conditions;
(2) the short and long term risks to people, animals and the environment associated with implementing the alternative, and
(3) the estimated present worth, including capital, annual operation and maintenance costs.
Based on this initial evaluation, five alternatives were considered for further examination:
1. Limited Capping
This alternative would meet the minimum requirements for compliance with the MCP.
The site would remain fenced and access restricted. The upland soils (where concentrations of lead and chromium are present to a depth of 15 feet, and exceed the Upper Concentration Limits established under the MCP) would be capped.
Waste pigment from the upper two feet of wetlands soil would be excavated, placed in the uplands and capped. The wetlands areas would then be reconstructed and restored (see text on right). Contaminated sediment in Paintshop Pond would be dredged and pigment would be removed from its banks. All dredged and/or excavated materials would then be moved to the uplands area and capped.
In each of the alternatives, the excavation of contaminated soils from the wetlands would also necessitate removing the existing vegetation. In Alternative #1, contaminated wetlands soil would be excavated and capped in the uplands, and the wetlands restored at their present location, which encompasses nearly seven acres. In Alternative #5, the wetlands would also be reconstructed at their present location after contaminated soil is excavated, treated and disposed off-site. In Alternatives #2, #3 and #4, new wetlands would be constructed adjacent to the current wetlands site and the new area would be one acre larger than the existing wetlands. In reconstructing the wetlands, the College would lay down new soils (loam and peat), then introduce a wide variety of vegetation, including bushes, plants and young trees. There would also be some seeding of the area to encourage additional plant growth.
2. Excavation and On-Site Encapsulation
This is the College's recommended alternative for implementation as described on page one.
3. Excavation, Stabilization, Reduction and On-Site Encapsulation
This alternative is similar to Alternative #2 except that pigment and soils with higher concentrations of metals would first be treated with a chemical that reduces the toxicity, then further treated with a stabilizing agent in order to reduce the mobility of the contaminated material. The treated and other excavated soils would then be placed in the lined cells and capped.
4. Excavation, Soil Washing and On-Site Encapsulation
This alternative is also similar to Alternative #2, except that the pigment and contaminated soil with higher metal concentrations would be washed with an acid solution to remove metals from the soil, before being placed in the lined cells and capped. The washwater used in treating the contaminants could either be transferred off-site to a hazardous waste facility, or further treated on-site with the cleaned water eventually discharged through the sewer system.
5. Excavation and Off-Site Disposal
In this alternative, pigment and contaminated soils and sediments from both the uplands and wetlands areas would be excavated and then shipped off-site for treatment and disposal at a licensed facility. Based on the concentrations of materials at the site - in order to meet the federal Environmental Protection Agencyís recently implemented Land Disposal Restrictions - the excavated material would have to be treated prior to its off-site disposal. Once the contaminated material has been removed off-site, the property can be restored and reused.
DETAILED EVALUATION OF ALTERNATIVES
Each alternative was evaluated in detail using criteria laid out in the MCP. A brief overview of the criteria follows.
1. Comparative Effectiveness
Whether the alternative will provide for a Permanent or Temporary solution to the problem (per the MCP) reuse, recycle, destroy, detoxify or treat hazardous materials on-site; reduce levels of hazardous materials at the site to achieve or approach what are considered "Background" levels.
2. Comparative Reliability
The degree of certainty that the alternative will be successful the effectiveness of any measures required to manage residues or remaining wastes, control emissions or discharges to the environment.
3. Comparative Implementability
The difficulty/ease in implementation, such as how technically complex each alternative is; how easily the alternative can be integrated with existing facility operations and other current or potential remedial actions; any necessary monitoring, maintenance or access requirements or limitations; the availability of necessary services, materials, equipment or specialists; the availability, capacity and location of necessary off-site treatment, storage and disposal facilities; and whether the alternative meets the regulatory requirements for any likely approvals, permits or licenses issued by the DEP, or other state, federal or local agencies.
4. Comparative Risks
Short term on-site and off-site risks posed during implementation of the alternative; on-site and off-site risks posed over the period of time it would take to meet the cleanup standards; and the potential risk to health, safety, public welfare or environment posed by hazardous material that may remain on-site after completion of the remedial action.
5. Cost Comparisons
The costs of implementing the alternative, including design, construction, equipment, site preparation, labor, permit, maintenance, operation and all other related costs; the costs of environmental restoration, potential damage to natural resources, including surface waters, wetlands, wildlife, fish and shellfish habitats; and how much energy is consumed during the operation of the alternative.
6. Comparative Benefits
- the benefit of restoring natural resources;
- whether it provides for productive reuse of the site;
- the avoided costs of relocating people and businesses or providing alternative water supplies; and
- the avoided lost value of the site.
7. Comparative Timelines
How long it will take to eliminate any uncontrolled sources of hazardous materials and achieve the MCP level of No Significant Risk.
8. Comparative Effectiveness and Non-Financial
Includes aesthetic values and public acceptance.
Based on consideration of all these criteria, the College recommends proceeding with Alternative #2 - Excavation and On-site Encapsulation.
WHERE DO WE GO FROM HERE?
Over the next several weeks, DEP will review and evaluate the College's recommended alternative. At the same time, the College will continue to evaluate alternatives for cleaning up groundwater at the site and sediments in Lake Waban.
We will continue to keep you informed by providing more updates and fact sheets. We also plan on holding a Public Information Session in early May, so we can meet with members of the public and talk about our plans for cleanup, and how it will benefit the College and the entire community.
This is one in a series of information sheets designed to answer some of the questions that you and your neighbors may have about the cleanup process. We recognize that keeping an open dialogue with you is an essential part of our commitment to safeguarding human health, the environment and community well-being.
(Click here to view the May 1998 Information Sheet)
Mary Ann Hill
Director of Public Information and Government Relations
Massachusetts Department of Environmental Protection
205A Lowell Street
Wilmington, MA 01887