PB95-963124
                            EPA/AMD/R05-94/261
                            March 1995
EPA  Superfund
      Record of Decision Amendment:
      Arrowhead Refinery Co.,
      Hermantown, MN
      2/9/1994

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                Amendment To The Record of Decision
                            Declaration


Site Name and Location

Arrowhead Refinery Superfund Site
St. Louis County
Hermantown, Minnesota

Statement of Basis and Purpose

This decision document amends the selected remedial action for the
Arrowhead Refinery Superfund Site (Arrowhead) developed in
accordance with the Comprehensive Environmental Response,
Compensation and Liability Act of 1980  (CERCIA) , as amended by the
Superfund Amendments and Reauthorization Act of 1986  (SARA) and,
to the extent practicable, the National Oil and Hazardous
Substances Pollution Contingency Plan  (NCP).  This amendment to
the Record of Decision (AROD) makes fundamental changes to the
remedy selected in the 1986 Record of Decision (ROD).

This AROD does not make  " fundamental changes*  (within the meaning
of the Environmental Protection Agency's Office of Solid Waste and
Emergency Response Directive 9355.3-02FS-4,  "Guide to Addressing
Pre-ROD and Post ROD Changes", April 1991) to the groundwater
remedy selected in the ROD.  Therefore, this AROD does not
constitute an amendment of that* groundwater remedy.  However, this
AROD does document minor differences in the groundwater remedy
which the Agency intends to implement.

This AROD is based on the administrative record file for the
Arrowhead Site.

The State of Minnesota, through the Minnesota Pollution Control
Agency (MPCA), has verbally concurred with the amended remedy.

Assessment of the Site
                    •

Actual or threatened releases of hazardous substances from this
Site, if not addressed by implementing the response action
selected in this AROD, may present an imminent and substantial
endangerment to the public health, welfare and/or the environment.

Description of the 19*6 BOD Remedy
           »
The site contaminated media were originally divided into three
parts: 1) groundwater, 2) sludge,.filter cake and oil saturated
peat  (source material) and 3) contaminated soils and sediment?.

The 1986 ROD specified that the following remedial actions be
implemented:

     e Extend the nearby municipal water system to replace private

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water supplies  to  ten residences  most  likely to be affected by
groundwater  contamination from Arrowhead.   Abandon individual
wells formerly  used  as drinking water  supplies in accordance with
state well codes.

     • Design and  install a  groundwater  extraction and  treatment
system to capture  and restore  the contaminated groundwater beneath
the site and to prevent off-site  migration  of the contaminated
plume.  Discharge  extracted  contaminated groundwater to the
Western Lake Superior Sanitary District  waste water treatment
facility  (WLSSD).  Potential ingeetion of on-site groundwater has
an excess lifetime cancer risk of 10'2  for either a residential or
a commercial/industrial setting.   Operate the extraction and
treatment system until 10"6 lifetime cancer  risk levels are
achieved  (estimated  at 25-50 years).

     • Excavate and  incinerate on-site,  4,600 yds' of  source
material and 20/500  yds3 of contaminated soils and sediments  with
concentrations  of  carcinogenic Po?"nucl«»T  Aromatic Hydrocarbons
(PAHs) and Volatile  Organic  Compounds  (VOCs)  that exceed
the 10"* excess  lifetime cancer risk in a commercial/industrial
setting and/or  concentrations  of  lead  and other non-carcinogens
that exceed  adult  chronic acceptable intake levels (AIC).
Determine the leaching characteristics of the resulting ash. If
the ash is non-hazardous by  the EP toxicity test, place it back
on-site. if  hazardous,  stabilize  and place  in a subtitle D
landfill.

     • Conduct  further field studies to  ennance site
characterization.  In response to a request from the Minnesota
Pollution Control  Agency (MPCA),  the ROD stated that the
technologies eliminated early  in  the FS  - vitrification, chemical
fixation, and cementation •  would be reevaluated and that bench-
scale studies would  be considered.

The total cost  of  this remedy  was estimated at $23,000,000 in
1986.

The groundtfatex remedial design and construction have been
completed.   Minor  change* in the  operation  and maintenance of the
extraction and  treatment system,  which do not constitute
fundamental  or  significant change** including point of  compliance
and cleanup  levels,  are discussed.

Explanation  of  Fundamental Remedy Change

EPA conducted a solvent extraction study which indicated that this
technology would not be a suitable technology for the Arrowhead
Site.  MPCA  and the  Minnesota  Arrowhead  Site Committee  (MASC), a
group of  PRPs,  each  conducted  treatability  studies in an effort to
find  a  less  costly alternative to incineration for both source

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material, soils and sediments.  Technologies evaluated included
solid phase and slurry phase bioremediation,
stabilization/solidification, soil washing with lead removal,
thermal destruction in a cement kiln or other boilers and
industrial furnaces, and chemical dissociation with lead recovery.
With respect to the source material, the results of these studies
indicated that chemical disassociation of source material would be
the optimal method of remediation.  This technology removes lead
from the source material and provides a saleable 'off-spec* fuel.
Additionally, the lead may be recovered in a smelting operation.

Another very important discovery resulting from these studies was
that as soil samples were obtained and analyzed, PAH and voc
levels were consistently found to be below health based levels of
concern.  This .was verified in a separate field sampling study
conducted in June 1993.  Upon review of the early field studies,
it was found that there were only two PAH "hot spots" in the soil
and that these were likely due to cross contamination with filter
caka.  As a consequence of these findings, the soil and sediment
contaminant of concern is now only lead.  Therefore, treatment
technologies which targeted organic compounds in soils and
sediments, including incineration, have been discounted from
further consideration.

Description of Amended Remedy

The major elements of the selected amended remedy include:

     • Excavation of sludge and filter cake using a visually
contaminated standard; total volume approximately 4,600 - 6,100
cubic yards.

     • On-site treatment of sludge and filter cake by chemical
disassociation (re-refining) of the toxic compounds within the
sludge/filter cake matrix to produce a saleable "off-
specification" fuel and to recover lead in a smelting operation or
to stabilize and place in a permitted RCRA Subtitle D facility.

     •  Excavation of visually contaminated soils and sediments,
followed by placement of soils and sediments in a permitted RCRA
Subtitle D facility.

Discussion of Change in Grovmdwater Rowdy

     •  Operation and maintenance of the ground-water extraction
and treatment system until groundwater at the site perimeter meets
Maximum Contamination Limits  (MCLs) .

Statutory Determinations

     The selected remedy is protective of human health and the
environment, attains Federal and State requirements that are

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applicable or relevant and appropriate for this remedial action
and Is cost effective.  This remedy satisfies the statutory
preference for remedies that employ treatment: that reduces
mobility, toxicity or volume (MTV) as a principle element and
utilizes permanent solutions and alternative treatment  (or
resource recovery) technologies to the magimnn extent possible.

Because this remedy will not result in hazardous substances
remaining on-site above health-based levels, the five-year review
will not apply to this action.
   ^ Approved        	Disapproved
Regional Administrator

Date

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