Cornell University
Radiation Disposal Site
Feasibility Study
February 1999
EXECUTIVE SUMMARY
McLaren/Hart, at Cornell University’s request, has performed a feasibility study to
identify the most appropriate and cost-effective clean-up and containment approach for
Cornell’s radiation disposal site in Lansing, New York. The study was conducted in two
major phases:
1) a preliminary screening of alternatives based on their effectiveness and
implementability in meeting remedial goals and objectives for the site
2) a detailed comparison of the proposed alternatives to a list of seven criteria
specified in the New York State Technical and Administrative Guidance
Memorandum, for the selection of remedial actions at inactive hazardous waste
sites and numerical ranking of the alternatives using these criteria.
This process identified the approach that is consistent with regulatory requirements,
meets site-specific goals and objectives for remediation, and is cost effective. The final
remedy will be selected by the New York State Department of Environmental
Conservation (NYSDEC) in a formal process that seeks and considers public opinion.
Once selected, the NYSDEC will document the final remedy in a Record of Decision
(ROD) that will be implemented by Cornell.
The radiation disposal site is located north of Snyder Road in the Town of Lansing,
Tompkins County, New York. It is an approximately two-acre inactive low-level
radioactive waste landfill. The site was operational from the late 1950s through June
1978, during which time wastes generated during radiological research activities were
buried in trenches excavated at the site. Based on RDS site dimensions the estimated
maximum volume of the RDS waste material is 1,044,000 cu. ft. or 38,667 cu. yards of
which approximately 255,000 cubic feet (9,400 cubic yards) comprises low level radioactive waste. In 1996 an interim cap was installed over the disposal area, drainage was
improved, and access to the site was further restricted using improved fencing and
locking gates.
A remedial investigation and supplemental remedial investigation were performed at the
site from October 1995 through December 1997. The major conclusions from these
investigations, as they relate to the feasibility study, are:
1) both ground water and surface water are the media requiring remediation
2) tritium, strontium-90, paradioxane, dichloroethylene, and benzene are the
contaminants of concern in ground water
3) paradioxane is the contaminant of concern in surface water
4) the contaminant that is most widespread in the ground water plume is
paradioxane, which is used to define the maximum extent of ground water
contamination, and
5) cleaning and containing the ground water will also clean the surface water
The primary contaminant transport pathway is through the ground water via a shallow,
highly fractured bedrock zone. The highest concentrations of contaminants are observed
in monitoring wells immediately adjacent to the site. It is estimated that 96% (by mass) of
the paradioxane plume with concentrations greater than 50 parts per billion (ppb) is
within the bounds of the Cornell University property north of Snyder Road. NYSDEC
has set a preliminary clean-up criterion of 50 ppb for paradioxane for ground water at the
site.
Detection of paradioxane in surface waters generally has been limited to those sample
locations north of Snyder Road. Capping the site eliminated potential impacts from
runoff upon surface water. It also halted infiltration of surface water through waste
materials in the site disposal area.
The conceptual plan for an Interim Remedial Measure was approved by the NYS
Department of Environmental Conservation in August of 1998. This second interim
remedial measure is planned for 1999. A series of ground water extraction wells, located
just north of Snyder Road and downgradient of the disposal area, will be used to collect
and monitor ground water issuing from the radiation disposal site. Recovered ground
water will be pumped to the plant located next to Cornell’s chemical disposal site for
treatment by a specially designed mechanism. Discharge standards for the plant are
being modified by the NYSDEC to include the addition of the radiation disposal site’s
treated water; after treatment to meet these discharge standards the water will eventually
be discharged as surface water.
Procedures and criteria used in this feasibility study were designed to select the most
environmentally sound, technically feasible, and cost-effective remedial action alternative
for this site. This was accomplished through a phased evaluation that included defining
goals and objectives, identifying and screening appropriate remedial technologies and
alternatives, and conducting a detailed and comparative analysis of retained alternatives.
The site-specific goals and objectives that were developed for the site are as follows:
 Minimize future contaminant releases from the radiation disposal site
 Meet regulatory requirements
 Eliminate or minimize off-site migration of contaminated surface water and
ground water
 Minimize the generation of new radioactive and mixed (radioactive and
hazardous) wastes during the remediation process
As part of the preliminary remedial alternative evaluation, six alternatives were
developed for the site. These were:
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Alternative 1: No further action beyond capping and ground water interim
remedial measures
Alternative 2: Containment of source area with a slurry wall and a grout curtain;
ground water recovery, treatment, and discharge; and natural attenuation.
Alternative 3: Containment of source area with a slurry wall; source area ground
water and ground water recovery, treatment, and discharge; and natural
attenuation
Alternative 4: Containment of source area with a slurry wall, a grout curtain, and
bottom sealing; ground water recovery, treatment, and discharge; and natural
attenuation
Alternative 5: Excavation of source area and off-site disposal; ground water
recovery, treatment, and discharge; and natural attenuation
Alternative 6: Excavation of source area and on-site disposal in a new landfill;
ground water recovery, treatment, and discharge; and natural attenuation.
All of the alternatives evaluated as final remedies for the site incorporate both the
capping and ground water interim remedial measures, as appropriate. The capital costs of
the interim measures have not been included in the cost estimates for the alternatives. The
operation and maintenance costs of the interim measures have been included for each
alternative, as appropriate.
In the preliminary screening, the six alternatives were evaluated primarily on:
 their ability to meet site-and-medium-specific remedial goals
 their implementability, and
 their short-term and long-term effectiveness.
All alternatives except the first comply with all the requirements of the New York State
Standards, Criteria, and Guidelines and the site-specific remedial goals and objectives.
Based on the preliminary screening, only Alternative 4 was not retained for further
analysis; it involves placing a bottom seal of grout below the disposal area using
horizontal drilling. This technology would have been far more difficult to implement, and
no more effective than other alternatives screened (such as Alternative 2).
Following the preliminary screening, a detailed comparative analysis was performed for
the five remaining alternatives. Each was evaluated against the following seven factors,
together with an eighth non-weighted criteria of community acceptance:
 protection of human health and environment
 compliance with the New York State Standards, Criteria, and Guidelines
 short-term effectiveness (construction phase)
 long-term effectiveness (operations phase)
 reduction of contaminants’ toxicity, mobility, and volume
 implementability, and
 cost
With the exception of Alternative 1, the overall ratings of the alternatives were
comparable when evaluated against the first six criteria listed above. Generally, all the
alternatives provided overall protection of human health and environment, with
Alternative 1 providing the least protection. The estimated costs developed for
comparison of the alternatives ranged from $5,826,000 for Alternative 1 to $154,807,000
for Alternative 5.
With NYSDEC guidance, a numerical scoring was made for each of the alternatives
using the criteria identified above. The scores ranged from a low of 62 for Alternative 1
to a high of 79 for Alternative 2, with the higher value indicating greater compliance with
the evaluation criteria. Based upon this comparative analysis, Alternative 2,
containment with a slurry wall and a grout curtain; ground water recovery,
treatment, and discharge, and natural attenuation, is the recommended alter-native.
This alternative is capable of fulfilling all of the goals and objectives of the radiation
disposal site remediation in a cost-effective manner. This alternative also should be
favorably viewed by the community since it best complies with all state standards,
criteria, and guidelines and remedial goals.
This recommended alternative involves the installation of a vertical subsurface barrier
wall (a slurry of bentonite and soil) around the perimeter of the radiation disposal area,
and a subsurface grout curtain, at depth, to seal the fractured shale. The existing cap
would be extended over the slurry wall, thus eliminating direct contact with the waste
materials and preventing surface water from percolating through the waste. The ground
water recovery and treatment system would be operated to stop further movement of
contaminants past Snyder Road by capturing and treating ground water. The current
monitoring program will be revised to monitor both the effectiveness of the source and
plume containment measures and the plume south of Snyder Road that is not captured by
the ground water recovery system.
Thus, Alternative 2 will effectively isolate the source area and prevent further migration
of paradioxane in ground water above 50 ppb, thus meeting remedial goals and objectives
and complying with regulatory requirements.