United States
Environmental Protection
Agency
Off ice of
Emergency and
Remedial Response
EPA/ROD/R03-91/106
December 1990
&EPA
Superfund
Record of Decision
Mid-Atlantic Wood
Preservers, MD
-------
50272-101
REPORT DOCUMENTATION 1'. REPORTNO.
PAGE EPA/ROD/R03-91/106
1 ~
I. A8dpIenI'8 Acc:ea8Ion No.
.. 1188 8nd S&M8a
SUPERFUND RECORD OF DECISION
Mid-Atlantic Wood Preservers, MD
First Remedial Action - Final
7. AuIIor(8)
5. A8port D8Ie
12/30/90
..
I. P8rf0nnlng OrpnIDtIon Aept. No.
.. PilrflAntlllll OrpInIDton ..... ... AdIhu
10. PfoIectITalllWork Unit No.
. .
11. ConIr8d(C} or ~G) No.
(C)
.
(0)
12. SpoI..q 0rprUaII0n NIm8 ... AdIh88
U.S. Environmental Protection
401 M Street, S.W.
Washington, D.C. 20460
11. Type of ~ . P8t1ocI Covered
Agency
800/000
14.
-
15. Supplementary No,"
111. Ab81r8ct (UmIt: 200 _rcI8)
The 3-acre Mid-Atlantic Wood Preservers (MAWP) site is a wood treatment facility in
Harmans, Anne Arundel County, Maryland. Land use in the area is pr.edominantly
industrial and residential, and a wetland area traversed by Stony Run Creek lies 600
feet west of the site. Since 1974, the facility has been used for pressure treatment
of lumber using chromate copper arsenate (CCA) as the wood preservative. The site is
divided into two areas: a Treatment Yard on the eastern half of the site, and Storage
Yard on the western half. The Treatment Yard contains CCA storage tanks, a pressure
cylinder, and a drip pad area. In 1978, the county. determined that water in a shallow
residential well down gradient of the site was contaminated with high levels o£
hexavalent chromium. Subsequent investigations by the State in 1978 revealed that soil
and ground water contamination by chromium and arsenic was the result of an overflow
pipe from a CCA storage tank. Under an agreement with the State, MAWP removed 26 cubic
yards of contaminated soil beneath the overflow pipe, modified the CCA storage system,
and installed a concrete drainage pad to collect drippings and reduce future
contamination. However, offsite investigations by EPA in 1983 identified elevated
levels of arsenic and chromium in ground water. Further EPA and MAWP studies
(See Attached Page)
17. Document An8/y8I8 L D8acrIpCora
Record of Decision - Mid-Atlantic
First Remedial Action - Final
Contaminated Media: soil, gw
Key Contaminants: metals (arsenic,
Wood Preservers, MD
chromium)
b. Identlfler8lOpen-En Tenna
Co COSA TI FIeIdIOroup
11. AYIIIabIIty ~
18. Sea8ity C1888 (ThIa Repor1)
None
20. Sea8ity C1888 (ThIa P8ge)
Non4=!
21. No. of Pages
66
22. Price
(See AHSl-Z38.18)
See tn.IructIOM on ~-
272 (4-71)
(formetty NTlS-35)
Department 01 Commerce
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EPA/ROD/R03-91/106
Mid-Atlantic Wood Preservers, MD
First Remedial Action - Final
Abstract (Continued)
documented onsite arsenic-contaminated soil, the result of removing treated wood
prematurely from the drip area before it had dried, as the principal threat. In
addition, these studies identified approximately 5,200 cubic yards of degraded soil,
to an average depth of two feet, in the Treatment Yard drip pad area and in the
westernmost third of the Storage Yard. Residential ground water metal contamination
levels were found to be at much lower levels than detected in earlier investigations;
arsenic was not detected, and chromium was detected above the MCL in only one well.
This Record of Decision (ROD) addresses contaminated onsite soil and ground water.
The primary contaminants of concern affecting the soil and ground water are metals
including arsenic and chromium.
The selected remedial action for this site includes excavating and-stabilizing
approximately 20 cubic yards of onsite soil contaminated with arsenic levels. greater
than 1,000 mg/kg (referred to as hot spots), followed by offsite disposaL; capping the
remaining soil with arsenic concentrations between 10 mg/kg and-:l,OOO mq/kg. with an
asphalt/concrete cap; constructing an enlarged and roofed drip pad which is .consistent
with new wood treating regulations; allowing natural attenuation to lower chromium
levels in ground water; monitoring sediment, ground water, surface water, and air; and
implementing institutional controls including deed restrictions. The estimated -
present worth cost for this remedial action is $322,400,.:- which includes an annual O&M
cost of $6,500 for 30 years.
PERFORMANCE STANDARDS OR GOALS: Chemical-specific goals for soil are based on
achieving a 10-5 cancer risk level. The chemical-specific goals for ground water are
based on Federal MCLs including chromium 50 ug/l: EPA feels that MCLs will be
achieved by natural attenuation within 3 months after construction ,is completed.
.~
h" .
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RBCORD OP DBCISION
KID-ATLANTIC WOOD PRBSBRVERS SITE
DBCLARATION
site Name and Location
Mid-Atlantic Wood Preservers Site
Harmans, Anne Arundel County, Maryland
statement of Basis and Purpose
,.-.
.- ".
This decision document presents the selected remedial action
for the Mid-Atlantic Wood Preservers Site in Harmans, Anne
Arundel County, Maryland, which was chosen in accordance with the
requirements of the Comprehensive Environmental Response, .
Compensation, and Liability Act of 1980, as amended (CERCLA),
and, to the extent practicable, the National Oil and Hazardous
Substances Pollution Contingency Plan, 40 C. F .'R. Part 300 (NCP).
This decision document explains the factual and legal basis for
selecting the remedy for this Site.
The Maryland Department of the Environment (HOE) concurs
with the selected remedy. The information supporting.this
remedial action decision is contained in. the~administrative
record for this Site. ..
.
.":..: "i
'.
Assessment of the Site
Actual or threatened releases of hazardous substances,
pollutants or contaminants from this Site, if not addressed by
implementing the response action selected in this Record of
Decision (ROD), may present an imminent and substantial
endangerment to public health, welfare, or the environment.
DescriDtioD of the Selected Remedv
The remedial action selected in this document is presented
as the permanent remedy for reducing risks associated with human
contact with contaminated soils at the Site. This remedy is
comprised of the following major components:
Excavation, 'stabilization and offsite disposal of
"hot spots" of highly contaminated soils (greater
than 1,000 mg/kg. arsenic) which have been
determined to be a principal threat;
-------
capping of soils containing arsenic at .
. conc~ntrations greater than 10 mg/kg but less than
1,000 mg/kg with an asphalt/concrete cap;; .'
. . . - ..
Construction of an enlarged roofed drip ::pad, , ,
consistent with new wood treating regulations;
Environmental monitoring to ensure the
effectiveness of the remedial action; and
Implementation of a deed restriction.
. \.,~'. ~ -
1; 'J
,
,
o
Declaration of statutory Determinations
..'
~ :
. The selected remedial action is protective of human healtK~ .
and the environment, complies with Federal and State requirements:
that are legally applicable or relevant and appropriat~, to the ~ ;
remedial action, and is cost-effective. The remedy utiriz'es' .
permanent solutions and alternative treatment (or resou'rcei,. .'
recovery) technologies to the maximum extent practicable, and it'
satisfies the statutory preference for remedies that employ' . .
treatments that reduce toxicity, mobility or volume as their:
principal element. . : .
.,
'f
f
Because hazardous substances, pollutants or contaminants: ,.
will remain at the Site following remediation, a review of' th1s":
remedial action will be conducted in accordance with the.' .
requirements of section 121(c) of CERCLA,42 U.S.C. S ..9.6.21,'(c) ,to:
ensure that human health and the environment a~e being protected'
by the remedi~l action being implemented.' '. .
. ,:....
",.:'..
t
~~
,"",
rvh'/90'
Date, .
,.."
"
::
. .
"
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DECISION SUMMARY
I.
SIT. LOCATION AND DESCRIPTION
The Mid-Atlantic Wood Preservers Site (Site or MAWP) is located
in Harmans, Anne Arundel County, Maryland, approximately 17 miles
south of Baltimore. The Site, approximately 3.17 acres, is situated
west of the Penn Central Railroad tracks and approximately 1,000 feet
north of Maryland Route 176 (Dorsey Road) (see Figure 1).
The site is owned and operated by Mid-Atlantic Wood Preservers,
Inc., and has been used for the pressure treatme~' dof lumber since
the facility began operation in 1974. Chromated-~Dpper arsenate
(CCA) is used as the wood preservative, protecting the wood against
. weather and insect damage. The Site is divided-into two, nearly'
equal areas--one east (Treatment Yard~ and one west (Storage Yard) of
Shipley Avenue (Figure 2). Each area. is surrounded by a chain link
fence and has a gate that is locked when the facili~y is not
operating. The majority of the ground surface is covered by
-compacted gravel, though about one-quarter of the Treatment Yard is
paved. .
Actual processing of the wood occurs in the main puilding on the
eastern half of the Site. This building houses both the product
storage tanks and a pressure cylinder. A "charge" 'of wood is placed
in the cylinder through an overhead door in the east end of the
building. The cylinder is then filled with the CCA from the storage
tanks and pressurized. After the proper amount of time, the excess
solution is pumped back to the storage tanks, and the charge of wood'
is moved to a temporary storage area on the drip pad. The drip pad
is sloped toward a sump located inside the main building so that
drippings from the freshly treated wood can be recycled, into the
.system. After the wood has stopped dripping, it is transferred by
forklift to the Storage Yard on the west side of Shipley Avenue.
The Stony Run Creek flows north through a wetland area 600 feet
west of the Site, extending approximately 4 miles before discharging
into' the Patapsco River near Elkridge, Maryland. Low flow in Stony
'Run restricts it to minor recreational use. The ground, surface at
'Mid-Atlantic Wood Preservers slopes 3-5% to the northwest. storm
water runoff from the Treatment Yard flows to storm drains ,alo~g
Shipley Avenue which discharg,e into a flood plain approximate],y 400
feet from stony Run, while that from the Storage Yard flows toward
Stony Run. .
The surrounding land use is mixed industrial and residential.,
Immediately to the south of the Site, east of Shipley Avenue, is a
trucking company. To t~e north of the site, east of Shipley Avenue,
are two warehouse buildings. North of the.site;'west of.Shipley
Avenue, is the Edwards property, where an abandoned house,
construction 'rubble, and excavation equipment are found. North of
the Edwards property is a vacant lot zoned for 'industrial use. North
of the vacant lot is the Hall residence. There are a few other
-------
SOURCE: U.S.G.S. 7H' Quid., Rtlty, Md , 1974
SCALE
FIGURE 1
LOCATION MAP
Dam** & Moor*
-------
..'
. ~-""--"-------,-..---------.-r-,-,-,,----,----,~.--'--------------'--------'------'~-.-;-;--.-
-'-----;;~'Y-."'" '"
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.. ~:A...:~"; ~;, 6.e:.. --,":: "A: .'.."..-~ ~ . :t :..~.~- >,,"'-. ~~ .. :"~.~~..,; ':: -~..;.~_. ~4-~A'~: ~ ..:~::'->:~,,~. "'.:.:' ,
''''n...",- ...,~.. 6..."- .. - -. -,,_.:.."-,,"-,. . _...."'~ "_A''''''''''''''''. ."'A..-~. ,"",
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"...."..~~.:-.~,....:.. ~...-. ~ .-......... ~ .. ... ..60.......0-,+ .. ,".. ... ..'" ~ '.Ii.'''' ....,.~ ... ..... ' .,... .,...... ~ ...... ,. .,..,:".#&.......... -.
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1---
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STORAGEYARD~ I
. i""- I
I '
, ,
, ,
,
-.I
ABANDONED
C""'- OWE LUNG
t::Jt
~
...
o
FORME A
~ MORHEAD
TRAILER
t:::::J
~
OUTFALL?
.~../.
PENN
CENTRAL,
c:
RR.
LEGEND:
o BUILDINGS
APPROXIMATE BOUNDARY
OF MAWP FACILITY
STORM SEWER
WETLANDS
o
I
700
.
SCALE
400 Fee'
I
~~~..~.:
.-...: :"4.:
FIGURE 2
MID-ATLANTIC WOOD PRESERVERS SITE
D8mes & Moore
-------
residences and light industries along shipley Avenue.
Washington International Airport occupies most of the
of the site, while most of the property west of stony
by Baltimore Commons Industrial Park.
Since the Mid-Atlantic Wood Prese~vers site is cleared, fenced and
paved with either'asphalt or crushed stone, vegetation and wildlife
on the site is sparse to nonexistent. The surrounding area, however,
supports a variety of plant and animal species. Vegetation found
near'the Site is primarily grasslands, woodlands and forested
wetlands. The forested area is typical of Eastern deciduous and pine
forests found elsewhere in Maryland. A forested wetland occurs in a
belt approximately 1,000 feet wide along Stony Run that ,provides a '
good"quality habitat for birds and small mammals. 'One species of
special concern has been found in the vicinity of the Site. A
population of swamp pink (Helonias bullata), listed as a threatened!
plant species under the protection of the Endangered Species Act, is i .
located adjacent to Stony Run approximately 4,000 feet downstream :of '
the Site. ' ' , ,
The Baltimore
property east
Run is occupied
site Geoloqy
The Mid-Atlantic Wood Preservers site is located within the: ' ,
western edge of the Atlantic Coastal Plain Physiographic Province: '
This Province is characterized by subsurface material consisting ,of,
an eastward to southeastward dipping wedge of Cretaceous to' " ",' '
Pleistocene age sediments. The sediments generally consist' of '
unconsolidated beds of clay, silt, sand, and gravel. The basal
sediments' in the Maryland coastal plain are part of the Cretaceous' ,
Potomac Group. These sediments have been depos~ted directly on top
of the crystalline rock of the basement complex, and in the area of:~,
the Site the sediments are exposed at the' surface. The Potomac Group' .
is approximately 500 feet thick at the site, and dips aboutrdegree' d,
to the southeast.
The' Potomac Group can be divided into: three formation's., ',From"",
bottom to'top these are the Patuxent, the Arundel, and the' Patapsco'
Formations which are approximately 100, 250 and 150 feet thick, .
,respectively. The sediments of all three formations consist: ot '.
discontinuous beds of clay, silt, sand, and gravel. Although the,~' ,
, proportions of these materials differ in the three formations, it is:>
often ,difficult to define a sharp boundfary between forma'tions.\':The "
lower patuxent Formation is composed mainly of coarse :'channel'.":'
deposits (sands and gravels). The abundance of: fine materia.r{clays',<'.
silty clays, and fine sands) increase in the .upper Patuxent. The' ;',
, Arundel ,Formation is a nearly continuous clay layer. The Patapsco :
, Formation is comprised of sands interbedded ~ith clay layers which'
vary abruptly in thickness and lateral extent.
From 'a hydrogeo log ic perspective," the patuxent . and,,;':.Patapsco" ",
Formations are water-bearing formations (aquifers), and~the Arundel
Formation is considered a confining layer. Minor confining. layers',
may also be present within the two aquifers. The Arundel's
effectiveness as a confining' unit means that the Patuxent'. cannot' be
affected by the site.
.. .-.
, ,
1
-------
Site geology was characterized by the collection of split spoon
samples in 10 well borings within the upper Patapsco Formation. The
boring 1098 reveal that the predominant geologic material beneath the
Site is poorly sorted sand with varying amounts of silt and gravel.
Discontinuous silty clay and clay/silt lenses are also present.
Figure 3 provides a representative cross-section of the Site showing
the relationship and relative thickness of the various units. Figure
4 shows the location of the cross section with respect to the Site.
These lenses appear to dip toward the southeast as would be expected
from the dip of regional formations. The thickness and continuity of
the clay appears to become greater toward the western end of the
site. .
site Hydrogeology
The Patapsco Formation contains discontinuous lenses of silty
clay, and clay and silt interspersed with the water-bearing sands as
were discovered beneath the MAWP site. The saturated portion of the
Patapsco aquifer that is above the lenses is referred to here as the
shallow or upper portion of the aquifer, while the saturated portion.
of the Patapsco below the lenses is referred to as the deep or lower
portion of the aquifer. Groundwater monitoring' wells were installed
above and below the site lenses. The lenses are not continuous
beneath the site; therefore, there is. probably. not a,complete
separation between the shallow and deep portions of the Patapsco
aquifer. The shallow water table at the Site is 8-12 feet below the'
surface. The groundwater in both the upper and lower aquifer ~s
moving toward the north-northwest. The linear velocity of
groundwater in the upper aquifer is estimated at 95-~18 ft/yr; in the
lower aquifer it is estimated at 34-41 ft/yr. . .
. Soils
Most of the natural soil at 1::he MAWP site. has' been covered by a
compacted gravel pad. The natural soil in the vicinity of the Site
is Evesboro loamy sand. The soil has very low available moisture
capacity, low natural fertility and is generally well draining. The
soil in the wetland area adjacent to Stony Run is Bibb silt loam. In
contrast to the Evesboro loamy sand, this. soil is poorly drained.
II.
8I~. HI8TORY AND BNFORCBKBNT ACTIVITIB8
In August 1978, water in a shallow residential well hydraulically
downgradien~ of the Mid-Atlantic Wood. Preservers facility was found
to be contaminated. On August 15, 1978, the Anne Arundel Count.y
Health Department sampled Richard Morehead's well (located
approximately 300 feet northwest of the Treatment Yard), and found it
to contain 7,700 ug/l of hexavalen~ chromium. The Maryland Water.'
Resources Administration (Md. WRA) also tested this well and observed
. a total chromium concentration of 19,500 ug/l. These levels exceeded
the Federal and State drinking water standard of 50 ug/l for
chromium. SUbsequently, Md. WRA identified MAWP as a user of
chromium and a potential source of groundwater contamination.
1
-------
W~$T
,'~'
WEll No.
110
6,
100
S+G
~
90 S+St
I- 80
W
W
~
Z
~ 70
I-
«
>
W
..J
Woo
50
40
3()
I ,
o
. :",
SAND WITH GRAVEL
AND SOME SilT
UPPER PA T APSCO
CwSt,
St/S
CLAy' ~ITHSll T AND ,SAN~
SilT WITH SAND
",,' " :~ . 1-": '1: ; -' .. " : "
",'~,--,
--- SAND
--
LOWER PATAPSCO
CLAY WITH SILT
, 50
.'
, 100 FEET
I
, ,
HORIZONT AL S~A~~
, -~.' ,.. ~ 64' .'
VERTICAL ~C~LE
" 1",~ ~6' "
',," "
, "
, , ' FIGURE~,', , , ',~ .' A'
SITE GEOLOGIC: CROS$SEFnON ~,~ , ,
. " .' PATAP5.CO Aa~IF~.~ , "
". '. .. .. . '. ~ ._-~ -
- ~
' ~
~
2/4
S+G
S
,SilT WITH CLAY
StwC
S..ome G
C w St+G
- S w G+C
SAND
CwSt
S+G w St
~
GRAVEL
AND
-
"
. ',', .",~.
S+G
---
----
C w S+St AND SAND
--
SIC w St ' -.
',...~ ~"':,.:,~,: '.-'~,
--
SAND AND CLAY
. -,'"
, I ,~. .,o:'~. ~ ,'- .
" '
" - ., ~
,--
---
EAST
A'
5
S
.%.
S+G
GwC
GwS+St
CwTR.G
S+G
D.mea & 0.0..
._~-
-------
.1..'
LEGEND:
r::J Buildings
--- Approximate Bound.y o' MAWP Facility
(!) Monitoring Well <30 Feet (u~r Patapsco)
o Monitoring Well >30 Feet (lower Patapsco)
U'locatlon o' Geotogic Cross Section
...
en
o
.~
f
lU
Q
11
o
I
, 200 Fef!'
I
SC A u:
o
o
o
r- -10-
C
.
,D
, '.
,. . ," ,
f.: .:
,. ;.
,
B' L
FIGURE 4
BORING LOCATIONS USED TO CONSTRUCT CROSS SECTIONS
n.lse from Ar,ial Photo
7
,9 . C'
,Ave
.t.. .
.~
........ . ......
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Between October 1978 and January 1979, the Md. WRA performed a
more detailed field investigation in the vicinity of Mr. Morehead's
well and MAWP in an effort to identify the source of contamination.
Md. WRA determined that Mid-Atlantic Wood Preservers had discharged
CCA into the soil and that groundwater beneath the facility was
contaminated with chromium and arsenic. More specifically, Md. WRA
identified an overflow pipe from a tank used for storage of the
aqueous chromium, copper, and arsenic wood treating solution as the
probable primary source of contamination for the groundwater. The
overflow pipe was located at the southwest corner of the main
building.
Based on the findings of the investigation Md. WRA issued
Administrative Order C-0-79-145, requiring Mid-Atlantic Wood
Preservers to develop a plan to remedy the groundwater contamination
in the area of the Site. Three amendments to the original order,
issued between October 1979 and January 1980, detailed specific
remedial measures to be taken and a schedule for such actions: to take
place. These mandated actions included removal of 26 cubic yards of
contaminated soil beneath the overflow pipe; modification of rthe
product storage system to prevent the release of overflows;;1 andfev
installation of a concrete drainage pad designed to collect CCA
drippings. In August 1980, MAWP notified the U.S. Environmental
Protection Agency (EPA) of its status as a small quantity generator,;
pursuant to 40 C.F.R. § 261.5, and received an EPA I.D. Number (MDD-
064882889) to facilitate the proper disposal of their unreusable
process wastes. The facility was inspected by the Maryland
Department of Health and Mental Hygiene on November 29, 1980, and was;
determined to be in compliance with Md;. WRA Administrative Order ;
C-0-79-145. During this time period, a'private lawsuit regarding
contamination of Mr. Morehead's well was filed and settled out of •
court. ,
A Site Investigation was performed at the Mid-Atlantic Wood
Preservers site by EPA in January 1983. This"investigation' included
collection of environmental samples for organic and inorganic
laboratory analysis. Sampling locations included surface waters and
sediments in Stony Creek upstream and downstream of the Site, soil
borings upgradient and downgradient of the Site, and previously
existing Md. WRA groundwater monitoring wells upgradient and
downgradient of the Site. The Site Investigation found that although
the concentration of arsenic and chromium in the groundwater had
declined by nearly one order of magnitude since September 1978, the
levels remaining still exceeded drinking water standards. Surface
water sampling revealed no evidence of arsenic or chromium pollution:
in Stony Run; however, copper, which is a component in the wood r
preserving solution, was detected at 120 ug/1 in the downstream
aqueous sample. The Site Investigation did not; reveal soil
contamination (samples taken were from offsite locations)." !
Based on the analyses of the groundwater monitoring wells,'-the
Mid-Atlantic Wood Preservers Site was proposed for the .CERCLA, v•
National Priorities List (NPL) in October 1984 and was-; finalized on
the list in May 1986. In July 1986, Mid-Atlantic Wood Preservers,
Inc. entered into a Consent Order and Agreement with EPA and :MDE to
-------
perform a Remedial Investigation and Feasibility study (RIfFS) at the
Site. Mid-Atlantic wood Preservers, Inc. submitted the final draft
of the study in August 1990.
III.
HIGHLIGHTS OP COMMUHITY PARTICIPATION
-
The RIfFS and' Proposed Plan for the Mid-Atlantic Wood Preservers
site were released to the public for comment on October 15, 1990.
These two documents were made available to the public in both the
administrative record and an information repository maintained at the
.EPA Docket Room in Region III and at the Provinces Library, Severn
Square Shopping Center, 2624 Annapolis Road, Route 175, Severn,
Maryland, 21144. The notice of availability for these two documents
was published in the Marvland Gazette on October 13, 1990, and the
AnnaDolis CaDital on October 14th and 15th, 1990. A public comment
period on the documents was held from October 15, 1990, to November
14, 1990. In addition, a public meeting was held' on November 8,
1990. At this meeting, representatives from EPA and MDE answered
"questions about the Site and the remedial alternatives under
consideration. The comments received during the public comment
,period, including those expressed verbally at the public meeting, are
addressed in the Responsiveness Summary, which is part of this Record
of Decision. EPA has thus met the public participation requirements
of sections 113 (k) (2) (B) and 117 (d) of CERCLA" 42 U,. S. C,., SS 9613
, (k) (2) (B) . and 961 7 (d) . . . , .
"":-",.,-." .", .
. :-'.
.
I .-:
.,
IV. ,SCOPE OP RESPONSE AC'l'XON
The principal concerns posed by conditions at the site are
summarized below. The remedial action will address these concerns by
treating arsenic-contaminated soils that constitute a principal
threat and preventing human exposure to soils which present an
,.unacceptable health risk. In addition, the existing facility will be
modified to prevent the -introduction of new contamination to site
media (i.e., soil and groundwater) and comply with the new
requirements regulating wood preserving facilities. This is the only
planned response action for this Site. .
V.
SUMMARY OF SITE CBARACTBRXSTICS
The contaminants of concern for the Site are chromium and
arsenic, which are directly related to the past and present .use of
chromated copper arsenate for wood preservation by the Mid-Atlantic
Wood Preservers facility. Copper is another substance found
abundantly in site soils due to the wood treating operation. Copper
. is generally ~ot considered a contaminant of concern with respect to
human health at the levels detected at the Site., Copper is, however,
of special interest because of its potential toxicity to aquatic
life. .
The rel~tively large release of CCA.solution from the' storage
tank overflow pipe in the mid-1970's led to chromium and arsenic
contamination of the groundwater beneath and downgradient of the
Site; however, recent sampling results indicate that there is little
residual effect from that release. Arsenic was not detected at any
a
-------
of the ten groundwater sampling locations; chromium was detected in
one shallow well at a concentration exceeding the current drinking
water standard. All surface soils located in the Treatment Yard and
the'westernmost third of the storage Yard have been contaminated with
arsenic, and to a lesser degree, chromium. The soil contamination is
most likely the result of wood preserving solution leaching from wood,
which has been removed from the concrete drip pad before it~has:
completely dried. ~ '
" ~..':
soils
. ;., '."'! .
. .. ",.1...
:'.~ t
Surface (0-0.5') and subsurface (3-3.5' and at the groundwater"
table) soil samples were collected and analyzed from thirteen onsite
locations (Figure 5). The analyses identified concentrations of
total chromium (trivalent and hexavalent species), copper and arsenic
in surface soils located in the Treatment Yard significantly higher
than background concentrations (Table 1). As can be seen from
Figures 6-8, the distribution patterns between metals are nearly
identical, clearly implicating the CCA solution as the source of
contamination. The highest concentrations of contaminants. ,are; ,found;
in samples taken near the drip pad. One surface soil: sample "taken'
adjacent to the drip pad, contained an arsenic concent'ration';,'great,er'~'
than 1,000 mg/kg (Sample SC-9A=1200 mqtkg arsenic). "" '
The analyses of the subsurface samples reveal a sharp reduction.
in concentrations of these metals at depth. At the 3 to 3.5 foot ,:\',
depth, the metals concentrations begin to approach the concentrations: '
expected in background samples. The only exception is the sample'
taken adjacent to the northern edge of the drip pad. All soil'
samples taken deeper than 3.5 feet contained concentrations of '
chromium, copper and arsenic representative of background levels~
, The depth to which contamination extends is estimated, to: average' 2'" ': '
feet in the Treatment Yard and westernmost third of the'Storage ~Yard.,'
The total volume of degraded soils located onsite tis est'imatedto' be:: ?;
approximately 5,200 cubic yards in place.' ,
Consideration of the geochemical properties of arsenic/ chromium:, 2
and copper indicates that the latter two metals are'adsorbed by all
soil materials, while the first--arsenic--becomesadsorbed' ,:
preferentially to clay and humic acids. Theseadsorptiom"
characteristics provide the principal explanation for ;;the"",
environmental behavior of these metals in' soil a:t the <;MAWP',s;ite."""
vertical migration of the three metals' has been ':impeded','by'::the'i'r;'.",
adsorption to soils underlying the site. ' , .' " ' . '.,
:"
On May. 24, 1990, EPA collected additional: surface so'ilsamp,les
from five locations on the MAWP site (Fiqure' 9). This samplinq event;:
was undertaken to determine theconcentratton of hexavalent chromium
relative to' the total chromium concentration. The samples were'" "
. analyzed for hexavalent and total chromium, and arsenic: {(Tab1e2;)'.,',
All five samples contained less than 1 mg/kg of hexava'lent chromiunt.::'
Total chromium results ranged from 23.2 mg/kg in' the eastern porti'on '
of the storage Yard to 570 mg/kg in the Treatment Yard ,near the drip
pad. Arsenic results ranged from 10.8 mg/kg in the eastern>portion ;:';;
of the storage yard to 633 mg/kg in the treatment' yard 'near:'the:drip;'
~
-------
LEGEND:
. c:J Buildings
--- Approximate Boundary 0' MAWP F8Cility
m Soil Sample (D-O.S' and 3-3.6'.
~ Soil Sample (P.O.5', 3-3.5', end water table.
S Soil Sample (GO.5'. .
...
U)
.~
!
au
{)
o
I
200 Feel
I
SCALE
Base from Aerial Pho,to
.._~--
o
Q
"
o
o
-------
------
- ---.- u_-- - -
-- ----- --- ---- -
. \' .
o
r--
---
, III 1 13 "
, 0
, ,
I 3 I
1 BB ,
, ,
" m2 4 I
ffil
--1
c::J
c~
'---
--
r--
, --
--.....
em 5 em,
, ,
I ' " !
, m 8 12 . ,
, . ,
1 111
I 7 . .,
!~ ',' 10. 9 I
-- J
.--. --. -- -- --- .
I '
FIGURE 5
SOil SAMPLING LOCATIONS
.- -"". - - -
Shipley
014
1315
Ave
" .
~
....... . .....
-~-- - -------
--------~--
-------
Ta})le 1
COncentrations of Chromium, Copper, and
in Soil Samples
Mid-Atlantic Wood Preservers
January 1989
Arsenic, ,
"
Sample Depth Chromium Copper Arsenic ;
( ft. ) (mq/kq) (mq/kq) (mq/kq)
<
SC-1A 0-0.5 198: 104 9,6 ;
,
SC-1B 3-3.5 BDL BDL BDL
SC-2A 0-0.5 60 BDL 3.3
SC-2B 3-3.5 5~1 BDL ,BDL'"
SC-3A 0-0.5 9.7 BDL 'BDL,
SC-3B 3-3.5 3.6 BDL BDL .. '
SC-4A 0-0.5 9.6 , BDL 3.2.
: "',
SC-4B 3-3.5 5.3 BDL BDL
I
SC-5A 0-0.5 201 129 30
. SC-5B 3-3.5 10 6.8 5.'5
SC-6A 0-0.5 70 49 , > 18 .
, ,
.SC-6B 3-3.5 8.7 BDL 6.7
"
SC-7A 0-0.5 62 53 61
,'..
SC-7B 3-3.5 7.4 BDL BDL', ..
;
SC-8A 0-0.5 377 348 223
""".:
SC-8B ~-' . 3 - 3, . 5 28 23 '14>
" '
SC-9A 0-0.5 865 1,280 1,200* ' I;c
, I..,'
SC-9B 3-3.5 82 19 ' ' 133
..'
SC-10A 0-0.5 346 362 403
SC-10B 3 - 3, . 5 4.6 BDL BDL'
.:f. :. .
. ,
2
. .' ~
. ..
-------
Table 1 CCODlt)
concentrations of Chromium, Copper, and
. in Soil sample.
Mid-Atlantic .ood pre.erver.
January 1989
ArSeDic
Sample Depth Chromium Copper Arsenic
(ft.) fmg/kg) (mg/kg) (mg/kg)
SC-11A 0-0.5 277 216 251
,
SC-11B )-).5 5.2 BDL - - -BDL
SC-12A 0-0.5 252 351 204
SC-12B )-).5 6.9 BDL 27
SC-13A 0-0.5 293 185 242
-
SC-13B 3-3.5 4.5 BDL BDL
Detection 2 5 2
Limits
Acid digestion technique used for sample analysis.
BDL - Below detection limit. .
. Single location identified above 1,000 mg/kg arsenic.
containing greater than 1,000 mg/kg arsenic have been
determined to be a principal threat.
50i15
1i
-------
LEGEND:
c::J Buildings
--- Approximate Boundary 0' MAWP Facility.
m Soil Sample (().0.5' and 3-3.5')
~ Soil Sample (().0.6', 3-3.5', and water table)
S Soil Sample t().0.5')
o Soil Sample (12.15' If'Id 22.24')
BDL Below Contract Required Detection Limit 01 2 mg/kg
.' 0
...
CI)
.~
S'
w
o
I
SCALE
(""
~iI~" from At'rhl Ph'",,:-,
D
200 Feet'
I "
o
c
, ,
o
o
r--
I -----,
I m96242~ I
I I
I I
, BI~t I
I I
I 1113 I
I 1E31
..... -
.... ..... --..J
r:::J
L::J
. 'r-=-
,
"30
1lm/'8 204.
,
,
r,
!.~6~ 403 . I
. : ..--:- --~----.~~J
..
, '
---
-~
223 Ill'
,
,
I
I
,
FIGURE 6,',
CONCENTRATION OF ARSENIC IN soi l (Mg/Kg), 0.0.5'
;. ," . , .,\
Shiplev
o
S
BOL
Ave
~
. "".
-------
LEGEND:
(::J Buildings
--- Approximate Boundary of MAWP Facility
m Soil Sample (o-O.S' and 3-3.5')
~ Soil Sample (o-O.S', 3-3.5', and water table)
8 Soil Sample (O-O.S')
o Soil Sample (12-15' and 22-24')
r--_-
I /98 293 -,
,m ~I
I I
I I
I BB/o I
I I
/ EB60 IOEB /
'---
--- ..... ----.J
t:::::::::J
C:J
o
o
o 8/0
... ShiPley
(I)
r--- Ave
,0 ,
.~ am , .
..
E
iU
lJ I ffJ 70
0 ' .'
0 I
I
'ffJ62
o
L
200 Feet
I
SCALE
~ " '.~, > .,
, .
Base 'rom Aerial Photo
FIGURE 7
CONCENTRATION OF CHROMIUM IN SOIL (Mg/Kg). 0-0.5'
_T_- -
--- ---"
.".-~ - - ~=-----=-...,;- . ~~=.,;.....=--~
~
1:-;-.1,;:-,._",- .,
-., .- ---
-------
LEGEND: '
c::J Buildings
--- Approximate Boundwv o' MAWP F8Cility
m Soil Sample (Q.O.5' end ~3.5')
~ Soil Sample'«()'O.5',~15', and water table)
,(3 sOil Sample f().O.5')
o Soli Sample (12-15' and 22-24')
BDL Below Contract Required Detection Limit of 5 mg/kg
, 0
..
CI)
.~
E
'&;j
.0
I
SC~LE. . ,
n;iic.:,'~~ 'fJC-:(Ci:
o
o
{)
:"". '"
rI
200 Feet
I ' ,
o
o
r--
I 104 -- -;85"
,m ~I
I I
I I
, B~t I
I ,
"
, ~l I!) I
~--- ~~
I::J
c~
r--
. ,.... ... . ~--------~
1"129 ~!
IImJ 49 ,
, ,
I I
I . 216
! 1!)53 362.'" I
- --. ..".'
..... - -- --- . ". ", J
' --
. ,',' ';-: .,:~ ,~. '.'" .'~' . ~ t
"
, ,"':
. "
. FIGURE 8"', " '
CONCENTRATION OF COPPER IN SOIL (Mg/Kg), 0-0.5'
'. :"':.'" ,. "; .~~. ." -,-'
.' . .'..
Ship leV
o
13
BDl
Ave
~
C..i..:::...:..~_c_,,~-.: ,-
-------
'.'
"'-
~,~!;... R",' 5W-2
. '-'If'.J~'--.,,~-l'>-.@
-...---- S. SE-5 SEA SE.]
LEGEND:
CJ Buildings f MAWP Facility
B ndary 0
Approximate ou .
--- Sample
A Surface Water
@ Sediment Sample
e!> Soil Sample
Storm Sewer
-.-
c::::.
tJ~
..
CI)
..
.~
E
W
o
I
700
I
SCALE
ABANDONED
---- OWE LUNG
CJ
o
,0
a
{J Q 0
E 'bridge
PENN
CENTRAL
RR.
400 Feel
I
FIGUREE~IMEN_T,,~ND
RFACE WATER, S. '1-':'-'.'...,- -, "
SU .., ." .
~.~;,t' III, .1
~~...
~ 5£./
5W./~...
~ :
--'"
~
-------
Table 2
ADalytical Results for onsit. Soil sampling:
Mid-Atlantic Woodpreserv.rs . .; .
May 1990 .
Sample Depth Hexavalent Chromium Copper.; Arsenic. ,
Chromium ..
",'
( ft. ) (mg/kg) (mg/kg) (mg /kg) ,: ; (mgjkg) ,
EPA-1 0-0.5 0.40 23.2 NA 10.8"
EPA-2 0-0.5 0.40 56.6 NA -- " 13.0
EPA-3 0-0.5 0.50 127.6 NA 199.2
EPA-4 0-0.5 0.70 157.2 NA 20.3
EPA-5 0-0.5 0.62 570.0 NA 633.3
EPA-6 0-0.5 0.58 106.1 NA . 93:.3 . .-1-
'.
,
!; ;
NA - Not analyzed.
'.".. .
. '
2.
-------
pad. This is meaningful because trivalent chromium (chromium III) is
far less toxic (200X) than hexavalent chromium (chromium VI) with
respect to noncarcinogenic health hazards and is not a suspected
carcinogen. Chromium VI is a potential human carcinogen through
the inhalation exposure route. Arsenic is a potential carcinogen
through the ingestion and inhalation route. Human exposure to
contaminated soils can occur through both the inhalation and
inadvertent ingestion route considering current site conditions.
Ground.. tar.
Ten groundwater monitoring wells were installed and sampled
during the Remedial Investigation (Figure 10). Seven of the
monitoring wells were screened in the upper Patapsco aquifer (above
the discontinuous clay lenses) and three wells were screened in the
lower Patapsco. The monitoring wells were sam~ledduring February
and March 1989 and the analyses were performed on unfiltered water
samples (Table 3). Four of the monitoring wells (Nos. 2, 3, 4, and
,8) were analyzed for the Target Compound List (TCL) and the Total
.Analyte List (TAL). The other six monitoring wells were analyzed for
arsenic, copper and chromium only. .
Chromium concentrations were found not to exceed current federal
or state drinking water standards (50ug/I') at eight of the
monitoring well locations;. however, analyses of groundwater extracted
from monitoring well Nos. 1 and 8 identified elevated levels of .
chromium (62 and 151 ug/l, respectively). The high concentration of
aluminum that was also detected in well No.8 suggested that the well
may have been improperly developed prior to sample collection.
Aluminum is relatively insoluble in water and is frequently used as
an indicator of unusually high levels of particulates in unfiltered
'samples. The presence of particulates in a water sample extracted
from a newly installed well yield analytical results that are biased
high. The water sample extracted from monitoring well No. ~.was not
analyzed for aluminum. .'
Monitoring well Nos. 1 and 8 were resampledusing both filtered
and unfiltered methods to determine if the previous sampling results
were representative of water quality in the upper aquifer. A.
. comparison of filtered versus unfiltered samples at well Nos. 1 and 8
showed dissimilar results. At well No.1, the chromium.concentration
in the filtered sample was below detection, while the unfiltered
sample was 88 ug/l chromium. This result indicates that the chromium
present is likely adsorbed onto particulates and not dissolved in the
water. only dissolved metals would be.expected.to be found in a
. .developed residential well. However, at well No.8, the filtered and
unfiltered analyses are virtually identical, with .68 and 69 ug/l of
chromium ,detected, respectively.. Therefore, at well No.8 the
. ~ ~.-
. 'Based .on the most recent scientific information documenting the
toxicity of ~hromium, EPA has proposed that the Maximum Contaminant
Level (MCL or "drinking water standard") for chromium in drinking water
be increased from 50 to foe ug/l. The Final Rule is pending.
10
-------
lEGEND:
CJ Buildings
--- Approximate Boundary of MAWP Facility
@) Monitoring Well"30 Feet (upper Patapsco)
o Monitoring Well>30 Feet (lower Patapsco)
..
CI)
.~
f
au
a
{)
o
I
200 Fep..
I .
SCALI::
Base from Aerial Photo
o
'.,.'
o
o
.0
"
r--_-
I --..,
, ,
~6 I
I I
I I
, I
I I
L . I
..... --. .... --....J
t::J
L~
r -10~
, '(i)" -.-.:':....'~- ' .,.
"D 1]4/
, ,
, , ,
to " '., , . ,
, ~~"":, . '",', ' ",
L ~ -. ~ - ~-- .!..(i)J
, .
'" ,'FIGURE 10 '
MONITORING WEll locATIONS
8
Ave
'."",,':.,>
>' .~. ,
~-;.,
7-
'--1
0';-';' "...
-------
Table 3
conc.n~rations of chromium, Copper, Arsenic, and. Aluminum
in Groundwater Samples
Mid-Atlantic Wood Preservers
.
Monitoring Well Date Chromium Copper Arsenic Aluminum
DETECTION LIMITS 10 ug/l 25 ug/l 10 ug/l 200 ug/l
UNFILTERED SAMPLES
GW-1 02-27-89 62 76 BDL NA
GW-1 05-04-89. 88 63 BDL NA
GW-2 02-28-89 37 BDL BDL 4,060
GW-3 02-28-89 BDL 26 BDL 259
GW-4 02-28-89 16 BDL BDL 1,150
GW-5 02-27-89 BDL BDL .BDL NA
GW-6 02-27-89 39 BDL BDL NA
GW-7 02-27-89 27 BDL BDL NA
GW-8 02-28-89 151 39 BDL 11,000
GW-8 05-04-89 69 BDL BDL NA
GW-9 02-27-89 BDL BDL BDL NA
GW-10 03-01-89 21 25 BDL NA
. ,~
-
FILTERED SAMPLES
GW-1 05;"04-89 BDL BDL BDL NA
GW-8 05-04-89 68 BDL BDL NA
Notes: . BDL = Below Detection Limit.
. NA - Not Analyzed
11
-------
chromium present is dissolved in the groundwater. Dissolved metals
that are present in groundwater extracted at a residential well would
be. available to receptors at the well. .
Well No.8 was installed in the shallow portion of the aquifer
and is hydraulically downgradient of the site. However, chromium was
not detected in the adjacent well No.3, which was installed in the
deeper portion of the aquifer. Comparison of chromium levels in the
other two shallow and deep well pairs also shows chromium levels to
be higher in the shallow portion of. the aquifer.' This . : .
differentiation between the shallow and deeper portion of the aqubfer '
indicat~s that the clay lenses may be restricting the vertical
migration of the groundwater. . .
The Federal and state drinking water $tandard for arsenic is 50
ug/l; EPA has proposed that 1,300 ug/l be promulgated'ets' the drinking
water standard for copper (final rule pending). Arsenic was not
identified above the detection limit (10 ug/l) and copper was not
detected above 76 ug/l in any of the ten monitoring wellls,. nor were
any of the TCL/TAL substances identified above background: . . ,
concentrations. Therefore, chromium is the only contam'inant:~of' :. ;.' .
concern in the groundwater. . .
Analysis of the current metals concentrations compared to ;pa~t' . i.
results indicate that the concentrations of arsenic and ch.romium 'have ' :
been steadily decreasing in the shallow aquifer below;: and ~own- ,
gradient of, the MAWP site. This phenomenon is illustrated in Figure
11 in which arsenic and chromium concentrations, measured in 'MD WRA
well No.6 and its replacement, Dames & Moore well pair Nos. 2 and 4,
. are. plotted over time. The shape of the curves suggest alogarith- .
mic drop in the concentration of metals during the 11-year.per.iod." A'
model (solute transport in groundwater) generated in aneffor.t. to
predict the effectiveness of natural attenuation' on the.chromium;,:,.
concentration in the groundwater suggests that levels'shou'ld reced'e;"'.
to below 50 ug/l within three months, assuming that no additional '
chromium migrates into the aquiter. '
. surface Water and sediments
Stony Run is not currently being impacted by. the Mid~'At'1antic 't ,;'. ,
Wood Preservers site. Three surface water samples. ;and f:ive 'sediment- !'. :'-:.'
samples wer. collected from Stony Run JFigur.e: 9,). All. of th'e .' '
collected 'samples were. analyzed for chromium,' copper'and:arsenic~':,
. (Table 4).. These metals were not detected in any sur,face water -'." " .
samples. Copper and chromium were detected in $ediment sampl:es'at "
concentrations within the normal range expected as background- for: .',
this area. Copper concentrations ranged from below det'ection', (5 : . ."
mg/kg) to 45 mg/kg and chromium ranged from 4.3. to 20 Jng/kg.'.;:Arsenic' ,'.
was not detected in any sediment samples.
80ils Near storm Sever outfall
Surface water runoff from the Treatment Yard flows::' to a ,storm ".:'
drain that runs northward beneath Shipley Avenue. The storm water is., ' :.
released from an outfall into a flood plain approximat&lY. 400' feet." '.
12
-------
~
~
~
en
Z
o
i=
4(
a:
~
Z
w
U
Z
o
u
a:
w
~
4(
~
Q
Z
;:)
o
a:
I.-'
35
30
..'
25
20'
15
10
5
o
8179
7n9
TIME
PRE.1989 DATA SOURCE: Vrobl.ky.1979
. Chromium MCl is 0.05 ppm .
Arsenic MCl is 0.05 ppm .
FIGURE 11
DECREASE IN METAL CONCENTRATIONS
IN THE VICINITY OF MD WRA WELL No.6
8/79
'.
. .
. .
---.J\t
---m
t -;7s9
D8m.. & Moore
-------
Table ..
concenuation8 of Chromium, Copper, and Arsenic in stony Run
Mid-Atlantic Wood Preservers
December 1988
Surface Water.
Sample Chromium Copper Arsenic
Detection Limits 10 uq/l 25 uq/l TOuq/l
SW-1 BDL BDL BDL
SW-2 BDL , BDL BDL
SW-3 BDL BDL BDL
,.
Sediments..,
,:. .~. ',\
: ~
; ~:'
Sample Chromium Copper Arsenic, " .~~;.
Detection Lind ts 2 mq/kq: , 5,mq/kq , ' 2imq l:kq ~ - :'~ ::;: 1~1r
SE-1 9.5 10 BDL
SE-2 4.3 BDL BDL.,
c'
SE-3 10 14 BDL
"
SE-:4 16 22 BDL '
..
SE-5 20 45 BDL :
'.
,
, .
. Surface water samples were unfiltered.;', , ,
.., Acid :digestion technique. used, for' sample :analysis; <":.
BDL ',- Below detection limit.' " , .
13
-------
Ta]:)le 5
Analytical Results for Soil Bear storm Sewer outfall -
Mid-Atlantic Wood Preservers
March 1990
Sample Depth Hexavalent Chromium. Copper Arsenic
Chromium
( ft . ) (mq/kq) (mq/kq) (mq/kq) (mq/kg)
SC-20A 0-0.5 NA 59.7 21.3 15.6
SC-20B 3-3.5 NA 54.4 47.8 37.1
SC-21A 0-0.5 NA 40.0 27.3 27.5
SC.;...21B 3-3.5 NA 15.2 15.1 BDL
Detection Limits 5 4 2
BDL - Below detection limit
NA - Not analyzed
..
II
-------
east of stony Run.Four soil samples were collected from two locations
near the storm sewer outfall on March 12, 1990. At each location, a
sample was collected at the surface (0-0.5 feet) and at~ depth (3-3.5
feet). The sampling locations were at the mouth of the outfall and
at a spot approximately 33 feet downgradient of the outfall in the
flood plain (Figure 9). The samples were analyzed for arsenic, total
chromium and copper. The analytical results are presented in ,Table
5. Comparing these results to the local mean background,
concentrations presented in Table 6, chromium and copper appear to be
present at background concentrations. Arsenic concentrations in
three of the four samples collected appear elevated over 'the expected
background concentration, but within the range of naturally occurring
soils. '
: /'
VI. SUMMARY OP SITB RISKS
.!;-,
1" "'"
, ,
A primary component of the remedial investigation is the public
health and environmental risk assessment. In this instance,the'risk
assessment defined the potential and actual iisks to human health and
the environment resulting from the presence ~f hazardO,ussubstances '
at the Site. ' : ", '
To determine whether there is an actual exposure or :.a. potential.":;,
for exposure at this Site with respect ta surface soils ~nd " , ~'
groundwater, the most likely pathways of contaminant release and
transport, and the human and environmental; activity patterns in the
area were considered. A complete exposure) pathway' has three
components: i.' . ,
1. a source of contamination that cart be released into the
environment;
2. a route of contamination; and
3. an exposure or contact point for: humans 'or the environment'
(plants and animals). '
., ;.
-r"
. -).
.;
"> .
Potential sources of contamination were' determined~', to:be:<"
. .
1. onsite surface soils;
2. upper-Patapsco groundwater (lower:patapsco' has notbeen/'
impacted); and,
3~ surface soil near storm sewer: outfalL;. ,
~.". ".
" ".
The contaminants, of concern are arsenicand~ chromi1im;-in the'"
surface soils and chromium in the groundwater. 'Potentially exposed'
human and environmental receptors are:', .
1. onsiteand neighboring workers through"incidental'ingestion of '
s6il (e. g., hand-to-mouth conta,ct) ,and;:,inhalation~of fugitive: .
dust; ,
2. children and adolescents through' incidental ''ingestion of:soil '-,
, (e. g'~, while playing near the storm ,sewer' outfall"); and', .' "
3. local residents and workers through ingestion of groundwa.ter;:"
15
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Table'
RADV.. and Averaqe. of Ketals in Uncontaminated 80ils.
Kid-Atlantic Wood pre.ervers
Chemical Regional Mean' Local Mean2 Range of3 Comments
Concentration Concentration Concentrations
(mg/kg) (mg/kg) (mq/kq)
Arsenic 7.4 6.1 1-50 Usually 10 mg/kg
or less
Chromium 52 63 1-1000
Copper 22 33 ' 2-100
-
1 - Mean of concentrations for soils collected throughout the eastern
United States (USGS, 1984).
2 - Mean of three soil samples collected from: Maryland counties
surrounding MAWP (USGS, 1981). Used. for compar~son to MAWP soils
data.
3 - Brown and Associates (1983)
. .
...,-.
'.0"
.
16
-------
There are currently no drinking water wells located in the upper-
Patapsco formation in the proximity of the Site; therefore the
groundwater is not currently available for use. Potable water is
provided by the Anne Arundel County public water supply. Because there
is no current exposure to groundwater, the calculated risks posed by
groundwater ingestion apply only to potential future usage and are not
risks currently posed by present site conditions.
To calculate the risk to public health, certain exposure;estimates
were made based on human activity patterns.
The dust inhalation rate was set 2.45 m3/hr for a 70-kg adult..: The
ambient dust concentration is assumed to be completely derived from
onsite soils. The concentration of arsenic and hexavalent chromium
in the surface soil represents the concentration of the contaminants in
the dust. The absorption fraction was specified as 100%.
The incidental ingestion rate of soil by onsite and neighboring
workers was set at 100 mg/day for a 70-kg adult. The absorption
fraction was specified as 100%. ; , ...
Common to both evaluated scenarios for workers, the exposure 5
frequencies were 5 days a week, 48 weeks per year for 40 years. A *
lifetime was considered to be 70 years. Present and future site "use
sceneries were industrial.
The incidental ingestion rate of offsite soil by children playing
near the storm sewer was set at 100 mg/day .^ The absorption fraction
was specified as 100%. The exposure frequency for an 8-12* year old,
31-kg child was once a week, 39 weeks per year for 4 years. The ?
exposure frequency for a 13-18 year old, 56-kg adolescent was; once a
week for 13 weeks per year for 6 years.
The ingestion rate of groundwater by local residents «was set at 2
liters/day for a 70-kg adult. The absorption fraction was specified as
100%. The exposure duration was assumed to be 70 years out of a 70-
year lifetime. . > r .
Toxicity Assessment Summary
Cancer potency factors (CPFs); have been developed? by EPA's
Carcinogenic Assessment Group for estimating excess lifetime cancer
risks associated with exposure to potentially carcinogenic chemicals
(Table 7). CPFs, which are expressed in units of (mg/kg-day) ~1, are
multiplied by the estimated intake of a potential carcinogen, in mg/kg-
day, to provide an upper-bound estimate of the excess lifetime cancer
risk associated with exposure at the intake level. The term "upper
bound" reflects the conservative estimate of the risks calculated from
the CPF. Use of this approach makes underestimation of the actual
cancer risk highly unlikely. Cancer potency factors are derived from
the results of human epidemiological studies or chronic animal
bioassays to which animal-to-human extrapolation and uncertainty
factors have been applied.
II
-------
Table 7
~ozicity par..eters for contaminants of Concern
Kid-Atlantic Wood pr..erver.
Compound PFo PFf RfDo RfD.
(mg/kg/day) ", (mg/kg/day)"' I
(mg/kg/day) mg/kq/day)
Arsenic 1.7 S8 SOb -- --
Chromium (VI) -- 41b (S X-10"3)b-_, -- --
Chromium (III) -- -- 1.0b .. --
Copper -- -- (3.7 X 10"2)' (1 X 10"2)'
Manganese -- -- 0.22' --
PFo
PFj
Potency Factor for oral exposure, carcinogenic effects.
- Potency Factor for inhalation exposure, carcinogenic effects.
RfDo - Reference Dose for oral exposure, noncarcinogenic effects.
RfD; - Reference Dose for inhalation exposure, noncarcinogenic effects.
avalue derived from unit risk value (IRIS, 1989) using drinking water -
exposure scenario of ingestion of 2 liters/day by ]O-kilogram adult.
The unit risk value has recently been withdrawn by USEPA and is being
revised. It is still used here for lack of ano~herval1Je.
bsource:
(IRIS, 1989).
Public Health Risk Evaluation Database (USEPA,1988).
- 'Source:
18
-------
Reference doses (RfDs) have been developed by EPA for indicating
the potential for adverse health effects from exposure to chemicals
exhibiting noncarcinogenic effects (Table 7). RfDs, which are
expressed in units of mg/kg-day,are estimates of lifetim~ daily,
exposure levels for humans, including sensitive individuals. Estimated
intakes of chemicals from environmental media (e.g., the amount of a
chemical ingested from contaminated soil) can be compared ' to the RfD.
RfDs are derived from human epidemiological studies or animal. studies
to which uncertainty factors have been applied (e.g., to account for
the use of animal data to predict effects on humans). These"
uncertainty factors help ensure that the RfDs will not underestimate~;
the potential for adverse noncarcinogenic effects to occur." : ~ : :' ;
Risk Characterization summary
Excess lifetime cancer risks are determined by multiplying the
intake level with the cancer potency factor. These risks are
probabilities that are generally expressed in scientific: notation
(e.g., 1x10.s or 1E-5). An excess lifetime cancer risk of 1X10.s :,,'
indicates that as a plausible upper bound, an individual has a, ,one' in, '
one hundred thousand chance of developing cancer as a resul:tof '~site-;~
related ~xposure to a carcinogen over a 70-year 'lifetime under 'the ""
specific exposure conditions at a site. The summary of total potential
carcinogenic risks (Table 8) shows that the potential carcinogenic ri'sk;,
at this site is dominated by incidental ingestion of onsite surface,' '
soils by workers. 'The incidental ingestion of contaminated surface" ~
soils and inhalatio~ of dust generated from those soils,~present a
potential carcinogenic risk of 5. 3X10.4 and 4. OX10-S , respectively. The
combined risk to workers from both the incidental ingestion and
inhalation exposure routes is 5.7xlO.4, meaning that approximately one
additional person out of 2,000 exposed' is at risk of developinqcancer.:
. The calculated carcinogenic risk presented by exposure, o'f"children to "
offsite soils near the storm sewer outfall is 1.2X10-~~(app~oximately.
one additional person out of 875,000). ~'
The potential for health effects resulting from exposure ,to. .
noncarcinogenic compounds is estimated by comparing an estimat'ed daily'
dose presented by site conditions to the reference dose .('Le." the dose',~,",
at which no adverse impacts would be :expected):. ; If this ratio: ,exceeds. '!:;','
1.0, there is a potential health risk. associated: with exposure! to that""
particular chemical. These ratios can' be:,added for exposur.es to ," 'i,"".: '.,
multiple contaminants. The sum, known.'as 'a Ha:zard :'!'ndex,: ,i's'no.t::a" "
mathematical prediction of the severity of toxic effects',,\,'but, ,rather:' a":'
numerica'l indicator of the transition' fromacceptabl'e to; unacceptable '"
levels. Table 9 presents a summary of the total, potential Hazard " " .
Indices for the exposure scenarios previously discussed.; , None .of:the" ;',
total Hazard Indices exceeds, 1. 0 for the exposure scenar:ios d'escribed ',< '
in the Remedial Investigation. . Thus, there' is no caus'e of concern: :for' " , '
noncarcinogenic risk to human health at the 'Mid-Atlantiic;. Wood' ,"
'Preservers Site. 'Although the concen'tration of chromium"'in the:
groundwater exceeds the current regulatory standard, the "risk'
assessment determined that consumption of the water wou'ld :not.~ present, "
an unacceptable health hazard (HI = 0.&9).' "
.' .'
..'
19
-------
Table 8
8U8aary of Total -Potential carcinoqenic Risk
Media Scenario Risk
Onsite Surface Incidental Ingestion 5.3 x 10.4
Soil/Dust. 4.0 x 10'5
(workers) Inhalation
Soils Near Incidental Ingestion 1.2 x 10-6
Storm Sewer..
(children)
Groundwater Ingestion ",.-None
(residents) . . .J..
. '...-..:, :'
~ -.1". .
.~ -'J ~ ;..
.
Onsite soil/dust risks were calculated using the upper bound
confidence limits (95th percentile) derived from the-treatment
yard. -
Offsite soil risks were calculated using the highest pollutant
concentrations detected during sampling. -
..
Note: Chromium is not a known or suspected carcinogen through the oral
ingestion exposure route.
. -.;-.-..
, "-
.
" -
1Q
-------
Table 9
8n-.ry of 'rotal potential Hon-Carcinogenic Hazard Indices
Media Scenario Hazard Index
Onsite Surface Incidental Ingestion .016047
Soil/Dust.
(workers) Inhalation .000567
Soil Near Incidental Ingestion .0002988
Storm Sewer..
(children)
Groundwater, Ingestion .89
(residents)
.
Onsite soil/dust hazards were calculated using the upper' bound
limits for the treatment yard.
Offsite soil hazards were calculated using the highest: pollutant
,concentrations detected during sampling.
..
If the Hazard Index exceeds 1.0, there is a potential health~
hazard associated with exposure to the< medium. '
,< ,
:1 .~. .,.
, '
.., "
1.1
-------
The range within which EPA manages carcinogenic risk is 10.' to
10.6. Arsenic is a natural constituent of all soils and is commonly
found at 1..818 exceeding 10.6 risk. To achieve a 10.6 risk, the
arsenic concentration in the soil would have to be reduced" to" 1.1 ppm
for worker exposure onsite and 3.8 ppm for children living offsite who
may be exposed to storm sewer soils by incidental ingestiQn. However,
these levels are below local mean arsenic background concentration
. (approximately 6.1 mg/kg) in naturally occurring soils. EPA and" MDE
have determined that preventing exposure to onsite contaminated soil
exceeding 10 mg/kg of arsenic at the Mid-Atlantic Wood Preservers site
would reduce the excess lifetime cancer risk to less than 10.5. This
remediation target would reduce the probability of developing cancer as
a result of exposure to the contaminants in the soil from one in 2,000
to less than one additional person in 100,000. The concentration of
hexavalent chromium in soils associated with a 10-~'risk is 2.0 mg/kg
(trivalent chromium is not a suspected carcinogen)". The "highest
observed hexavalent chromium concentration in onsite soils was 0.7
mg/kgi hence, the presence of chromium in onsite soils does not drive
the remedial action. Because there are no federal or state "cleanup"
standards for contamination in soil, these targets (10 mg/kg arsenic
and 2.0 mg/kg hexavalent chromium) were established for this site as
part of the risk assessment conducted during the RI/FS. .
One soil sample taken adjacent to the drip pad contained "an arsenic
concentration greater than 1,000 mg/kg, which presents a carcinogenic
risk above lX10.3 (one in 1,000). Any soils containing 1,000 mq/kg
arsenic or greater were determined to be a principal threat at the site
because exposure would lead to a carcinogenic risk two orders of
magnitude greater than levels that allow for unrestricted use. The
objective of the remedial alternatives developed for this Site was to
reduce direct contact exposure to an acceptable level, as well as to
,ensure that the migration of chromium and arsenic into the groundwater
is minimized.
Actual or threatened releases of hazardous substances from this
Site, if not addressed by implementing the response selected in this
ROD, may present an imminent and substantial endangerment to public
health, welfare, or the environment. .." ..
VII.
DESCRIPTION OP ALTBRHATIVES
" Six remedial alternatives (including No Action) were developed as
possible reaponse actions to provide an appropriate level of protection
to human health and the environment.
Alternative 1:
No Action - Monitoring only
capital Cost:
Annual Operating and Maintenance (O'M) Costs:
Present Worth:
Months to Implement:
02
$ 4,000
$45,000
None
2 All costs and implementation times referenced in this record of
decision are estimates.
22
-------
section 300.430(~) (6) of the National oil and Hazardous Substances
Pollution Continge~cy Plan .(NCP), 55 Fed. Reg. 8,849 (March 8, 1990)
(to be codified at 40 C.F.R. S 300.430(e) (6», requires, that EPA
consider a "No Action" alternative for each and every site to establish
a baseline for comparison to alternatives that do require action. This
alternative involves taking no action at the Site to remove, remediate
or contain the contaminated soils, nor modify the existing facility.
Under the "No Action" scenario, periodic air, surface water and
groundwater monitoring.would be conducted throughout the area. A
review would be conducted every five years as required under Section
121(c) of CERCLA, 42 U.S.C. S 9621(C). Thisalternative:does not
result in the reduction of any risks associated with the Site.
Alternative 2: Cover contaminated Soil Areas In The Treatment Yard
with Gravel, Cover contaminated Soil Areas In The storage Yard With
Geotextile And Gravel, Construct ADd Roof An Bnlarged Drip Pad, Allow
Natural Attenuation Of Groundwater contamination, Conduct Long-Term .
Maintenance and Monitoring" ADd Implement Deed Restriction;,~, .
capital Cost:
Annual O'M cost:
Present Worth:
, Months to, Implement:
$189,000
$ 11,500
$318,400
3
'!i ;.
.,; »;.: .~~ ;.-...
: .f
. ,'.
. ., i
, , ,
1,This alternative involves enlarging the' existing drip 'pad ',from', ,
24x43 feet to about 79x91 feet and covering the entire pad ~itH a roof:
(Figure 12). The expansion of the concret'e drip pad would, in effect, ,
contain the most contaminated soil area (adjacent to existing pad) with"
a low-permeability cap. This cap would significantly reduce the
potential leaching of contaminants, the generation of airborne dust, and"
human contact with contaminated soils beneath the pad.: ' The dripped:,: ,
chemicals and limited precipitation on the pad would be: coTlected'in:'a: "
properly lined sump pit and recycled. ,:contaminated soils ; (.exceeding, 10;
mg/kg arsenic) on the remainder of the ,site would be covered wi.th a
compacted and graded gravel layer to reduce the genera:tion' of " :"
contaminated dust and human contact with degraded soils. . The" .
identified areas exhibiting contamination' ,in excess of: the'abov:e~, -,
mentioned level include the western third 'of .theStorageYard 'and alL:-
unpaved areas in the Treatment Yard. Because the~ western' :end of, th'e, .'
, Storage Yard is underlain 'by soft soils, a layer of geot'extile' would be
placed on the ground surface' prior to. gravelplac'ement; :to, reinforce the' .
layer of gravel and minimize damage from vehicular traf.f:ic' andnatura:l: .-,'
causes. .
A model (solute transport in groundwater) generated',;ln an'. effort to' .
predict the effectiveness of .natural attenuation'on the chromium " .
concentration in the groundwater suggests' that< 'levels should recede': to ,=
below 50' ug /1 wi thin three months' of construction comp:letion',;; This':.
model assumes that no additional chromium. migrate's into the aquifer.".
Although construction of an enlarged, roofed drip pad and modification.,
of the facility's standard operating procedures consistent witb the new.,';
wood treatment regulations (55 Fed. Rea. 50,450: (December 6 , 1,990» ..
should eliminate the release of any new., contamination into: the' ,soils, ",~
II
-------
1r ,.
I: I
.......................H...
.
.
I
1t
"
I tAli
-
.... .... IBM 1
8OGII' .., ..,. I8r ..,.
I IJIIIDIO 0 0
--
... -
~ I
!!'
,.
.
...
"
b
. ..
181M
.... -
...
._'
@
1 '.
,'..
,-
I
!;..
. . . . . ~ .
FIRST DAY
DRIP AREA
48-ff'
.....
IIIIPP.
:.r.,., "
. , FIGURE 12
PROPOSED DRIP PAD EXPANSION
IN RELATION TO MAIN BUILDING
SOURCE: Mid-Atlantic Wood Preterver1
--"-~---
SECOND DAY
DRIP AREA
/
~~~
oa:
oC
a:~
ii
t-O
. -ff'
\»
.
t
.,.~
M8I1!J ,.~
W4'
- - -. -.
~ . . \
I
'.
IXI'SIIN5
ftVE
...
..
.
5
O.mft9. . MotWft
-------
the installation of a compacted gravel cover will continue to allow
some chromium currently in the soil to leach from soi15 exposed to
rainfall.
Periodic air, surface water and groundwater monitoring' 'would be
conducted to gauge the effectiveness of the remedy. . A deed restriction
would be implemented to ensure that containment components would not be
compromised by future use of the property. .
Alternative 3: Pave Contaminated soil Areas with Asphait/concrete"
construct And Roof An Bnlarged Drip Pad, Allow .atural Attenuation Of
Groundwater Contamination, Conduct Long-Term Maintenance:' and""
Moni toring, And Implement Deed Restriction .' , '
capital Cost:
Annual O'M cost:
Present Worth:
Months to Implement:
$239,000
$ 6,500
$312,200
3
'"
: ~:'~';,".'
, -'
. "
.~.. ~ . .J'!'
'.. .
, '.
, .. ,
, .' ' . .
Alternative 3 is similar to Alternative 2 with respect'to~source i
control (enlarging and roofing the drip pad)". Therefore, reference ::
should be made to Alternative 2 for the description of these actions.?
, This alternative, differs from Alternative 2 in the containment action
for the remaining, contaminated soils. \An asphalt/concrete cap would 'be
placed over those portions of the Treatment, Yard that would not: be .~. .'
covered by the treatment plant, enlarged 'drip pad, or currentlyJ paved' ; .~"
parking area. Contaminated soil areas in, the Storage Yard would ,also; ,.:,
be paved with an asphalt/concrete cap. Any contaminated:.so'i'1's that".may
have eroded outside the perimeter of the facility, to be' determined . ;:
during pre-design activities, will be consolidated underthe.cap. < .
paving material will be selected during the remedial design'.~' Figure .13", '.
presents the locations. of the areas of the. different: actions:.:" . '
The construction of an asphalt/concrete cap over thencontaminated".' .
soils would prevent direct contact with, and' inhalation' of.,' potentially' .;.
harmful dust generated from those; soils; provide a durable .'. .', ,,'
. air,' surface water and 'groundwater monitoring would, be' "conducted to,.'; .~." :--
. gauge the effectiveness of the remedy.,' A'deed restriction "wou1d:: be'.-,-':'
:, . implemented to ensure that containment".components would 'not be~. <.. ',.,' '.,
, compromised by' future use of the property.'" . ,
. ~..
. Alternative 3A:
, .
capital Cost:
Annual.O'M Cost:
Present Worth:.
Months to Implement
$
$
$
249,:4001, ;.
6)5:00~ ~'~,
322, 600l ~.
3-6 ~.,
"
This is a hybrid alternative' that' was developed :by \incorporating.a:',""
provision for treatment of "hot spots, II' areas containiri'g greaterth'a'n. '..;'
:' 1,000 mg/kg arsenic which are determined: to be;.a princ.i!pal'threat..at.. '~' ,
24
-------
LEGEND:
I:J Buildings .nd StructUf81
--- ApproxllNt. Bound.., 0' MAWP F8Clllty
~ Arsenic Contaminated Soils
Currently P.wed Are.
IIIllI Proposed Drip P8d .
.. Present Drip Pad
..
en
I .
.~
!
w
{)
I
o
I
200 Feet
I
SCALE
o
o
0.'
o
o
r_-=- ~---
r:-------~. -,
~%-----%-s,
F- -:. -:. -:.---- ---- -:. -:. -:.---- -:. -:. -.
-- - -:.- ~
I . ,
I I
, ,
I ,
, '. .' I
'- .
-
.... ..... -- ...J
I:::J
L~
';'.
Ave
FIGURE 13
~...t rrTf:n nr:urntl\t tU'TtnPiI r:nn IMPI rM~JlJTI\TIO~J
~
0/
-------
this Site, into Alternative 3. This, modification involves excavation,
stabilization and offsite disposal of any soils containing greater than
1,000 mg/kq arsenic. All other provisions of Alternative 3, described
above, would remain unchanged (soils containing greater than 10 mg/kg
but less than 1,000 mg/kg arsenic would be contained in place).
, It is difficult to estimate the volume of soils likely to contain
greater than 1,000 mg/kg arsenic because the remedial investigation
only identified one location exceeding that level (directly adjacent to
the existing drip pad). A conservative estimate assumes that soils to
a depth of one foot and within a two yard perimeter of the drip pad
contain concentrations of arsenic in excess of 1,000 mg/kg. Excavation
of such soils around the 30-yard perimeter would yield approximately 20
cubic yards of highly contaminated soil. These soils would be
stabilized by blending with portland cement, water and a proprietary
chemical used to chemically bind the contaminants and subsequently:
disposed at an approved offsite location. Alternative 3A would achieve
substantial risk reduction and meet the preference for treatment :o.f, '; ;
principal threats through stabilization of the highly concEmtrate'd; ~" ,
areas and by providing for the effective containment of other soils"
that will remain on site.
Alternative 4: Excavate contaminated Soils, Treat Excavated Soils Via'
Stabilization and Dispose In An Offsite RCRALandfill, Replace
Excavated Soils with Clean Pill, Construct And Roof An Enlarged Drip
pad, Allow Natural ~ttenuation Of Groundwater Contamination, And
Conduct Long-Term Maintenance and Monitoring ,
capital Cost:
Annual O&M cost:
Present Worth:
Months to Implem~nt
$2,700,000
$ 5,000
$2,750,000
6-12
-, ,
This 'alternative involves demolition and removal of: the , present,
drip pad, the excavation and removal of the uppermost 2",feet of soils.
(approximately 5,200 cubic yards) in the contaminated areas, disposal'
of those soils in an offsite RCRA landfill" and construqtion of a new' .
roofed drip pad similar to that described in Alternative 2., The
excavated soils would have to be stabilized prior to disposal in a
permitted hazardous waste landfill to. comply with land disposal: " ,"
restriction.. The pad would be broken up and steam clea-nec}, to' remove'
any residual CCA. The concrete debris.~ould then be sampled and ' . ,
disposed of appropriately. Because soll directly beneath the exist~ing """
dr ip pad has not been analyzed, it would also be sampled and handled'"
appropriately (offsite disposal if contaminated or remain in place ,if'
not). The excavated material would be replaced by clean 'backfill.
Periodic air, surface water and, groundwater~, monitoring would be.
conducted to gauge the effectiveness of;.the'remedy~ ','.. '
Alternative 5: Excavate Contaminated 'Soils,Treat bcavated Soil":':">
Onsite Via S.tabilization, Replace Treated soils,' Regrad. 'Site, , .
Construct A1ld Roof An Bnlarged Drip Pad, Cover Treated Soils with 'Clean
Fill And Gravel, Allow Natural Attenuation Of Groundwater . ','"
Contamination, And Conduct Long-Term Maintenance and Monitoring;
25
-------
capital C08ta
AnDual 0'. C08t:
Present wort!u
Months to X8pl..ent:
$ 943,900
$ 12,200
$1,080,000
'-12
This alternative is similar to Alternative 4 with. respect to
demolition and removal of the existing drip pad and the excavation of
contaminated soils; however, the excavated soils.would be treated
onsite using a stabilization process. The stabilization process would
result in a volume increase in the range of 30 to 50 percent. A.
suitable onsite location for long-term storage/disposal of treated
soils would be selected during the remedial design phase. In
compliance withRCRA land disposal requirements, a' low permeability
liner would be installed to underlie the stabilized soils and a
hydraulic barrier, less permeable than the liner would be constructed
over the disposal area. A new, roofed drip pad would be constructed
similar to that described in Alternative 2 (Figure 12). A deed
restriction would be implemented to ensure that the integrity of the
, disposal area would not be compromised by future use of the property.
'Periodic air, surface water and groundwater monitoring would be
conducted to gauge the effectiveness of the remedy.
Costs associated with liner and cap installation are not included
in the cost estimate.
VIII.
SUMMARY OF COMPARATIVE AHALYSIS OF ALTBRDTIVES
, The following nine criteria were used in..the evaluation of the
remedial action alternatives for the Mid-Atlantic Wood Preservers Site:
~Threshold Criteria
2)
primary Balancing
criteria
3)
4)
5)
6) .
'Modifying criteria
7)
'8 )
9)
1)
Overall protection of human health and the
environment; and
Compliance with applicable or relevant and
appropriate requirements.
Long-term effectiveness and permanence;
Reduction of toxicity, mobility or volume
through treatment;
Short-term effectiveness;
Implementability; and
Cost.
State/support agency acceptance; and
Community acceP1::ance.
, 10.
A brief description of each of these criteria is provided in Table
26
-------
,6.
9.
Ta):)le 10
NINB EVALUATION CRITERIA
1.
Overall Protection of Human Health and the Environment: Addresses
whether the remedy provides adequate protection and describes how
risks posed through each pathway are eliminated, reduced or ,
controlled through treatment, engineering controls or institutional
controls. ' ,
2.
ComDliance with ARARs: Refers to whether or not'a remedy will meet
all Applicable or Relevant and Appropriate Requirements (ARARs) of
federal and state environmental statutes and/or provides gro~nds
for invoking a waiver. It also addresses whether or not the 'remedy
complies with advisories, criteria and guidance that EPA andMDE
have agreed to follow. : ' ;
~ i -
, I
Lana-Term Effectiveness and Permanence: The ability ofth~ remedy
to maintain reliable protection of human health and,the,environment
over time once the "clean-up" goals have been met.' ,
3.
4.
.. ~
Reduction of Toxicitv. Mobilitv or Volume Throuah Treatment::,.:' ",'
Relates to the anticipated performance of the treatment ' ,
technologies with respect to these criteria. '
5.
. ; . .
Short-Term Effectiveness: Refers to 'the period of time needed to
achieve protection, and any adverse impacts on human health; and', the
environment that may be posed during ,the construction and, ' '
implementation, until "clean-up" goals are achieved.
ImDlementability: The technical and administrative feasibility of .
a remedy, including the availability of materials and services'
needed to implement a particular option.' ' '" '
7.' Cost: The following costs are evaluated: estimated. capital,
operation and maintenance, and net present worth. ,", "
8.
State AcceDtance: This indicates' whether, based 'on :its'r.eview of,""',
theRI/FS and the Proposed Plan, the State concurs, with, 'oppose's'or, ,
has no comment regarding the preferred al.ternati ve., ~:,' ,
Community AcceDtance: This indicates;' whether ,based""on .. its 'review.
of the RI/FS and Proposed Plan, the, community concurs, with" opposes"
or has no comment on the previously" identified ,preferred' ",' ,,'
alternative. Community comments and the Agency's. responses have' ','
,been included in the Responsiveness Summary.
" ,
27
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overall Protection of Human Health and the Bnvironment .
All of the alternatives, with the exception of the "no action"
alternative, would provide adequate protection of human health and the
environment by eliminating, reducing or controlling risk through
treatment or engineering controls. Alternative 3 (paving) would
provide a stable low-permeability barrier over the contaminated surface
soil (exceeding 10 mg/kg arsenic), thus. reducing the risks from
inadvertent ingestion and inhalation of fugitive dust and the potential
for migration of contaminants to groundwater. Alternative 3A
(treatment of "hot spots", paving) would couple excavation and
stabilization of highly contaminated soils to the provisions
incorporated in Alternative 3. since' arsenic and chromium. III are
naturally bound to soil particles, excavation and 'stabilization of
soils (Alternative 5) would be only marginally more effective at ." '... :
immobilizing the contaminants. Alternativ~ 4 (stabilization, offsite
landfilling) also provides a high level of' overall protection.
,.Alternative 3 would provide greater reliability and permanence in
preventing human exposure than Alternative 2 (gravel cover).
Construction of the enlarged drip pad is expected to result in the
gradual decline of chromium concentrations in the groundwater to below
the MCL by natural attenuation in the aquifer. The "-no action".
alternative is not protective of human health and the environment,,,
. since it would allow exposure to arsenic concentrations which could
result in carcinogenic risks above EPA's acceptable risk range (i.e.,
10.4 to 10.6). Therefore, this alternative is not discussed further in
this comparative analysis as an option for this site.
. -
compliance with ARARs
;' All alternatives, with exception of Alternatives 1 and'2, would
meet their respective applicable or relevant and appropriate
requirements of federal and state environmental laws (ARARs).
Chromated copper arsenate was listed as. a RCRA hazardous waste on
November 15, 1990; therefore " RCRA landfill closure requirements and
. land disposal restrictions are applicable. By controlling the source
of contamination, natural attenuation modeling suggests that chromium
concentrations should recede to below 50 ug/l chromium within three
months of construction completion. Paving the relevant areas
(Alternative 3) and implementation of a long~term groundwater
monitoring plan would meet RCRA closure requirements. The excavation
alternative. would meet land disposal restrictions through
stabilizatlon of soils and placement in ari EPA-appr,oved facility. The
enlarged, roofed drip pad included in all the action alternatives is
consistent with the new regulations for wood treating facilities.
, .
. .'.'
Alternative .3A (treatment of "hot spots", paving), Alternative 3,
(paving), 'Alternative 4 (stabilization, offsite landfilling), and
Alternative 5 (onsite stabilization), would comply with their
respective ARARs.
28
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Lonq-T8ra Bff8ctiveness and Permanence
All of the action alternatives incorporate construction of an
enlarged, roofed drip pad which should be very effective in preventing
future releases of chromated copper arsenate solution to the
environment. Alternative 4 (stabilization, offsite landfilling) would
have the highest long-term effectiveness because all degraded soils
would be removed from the site and disposed of in anoffsite landfill.
: Alternative JA (treatment of "hot spots," paving) is a hybrid of
,Alternatives J and 4. Soils presenting a principal threat (soils
containing greater than 1,000 mg/kg arsenic) would be removed,
stabilized and disposed of in an offsite landfill and exposure to
remaining degraded soils would be eliminated by containing the
contaminated soils onsite under a permanent asphalt/concre,te cap. The
deed restriction will guarantee the permanence of the remedy by
ensuring that the property is utilized'in a manner consistent with the
containment remedial objective. Alternative J (paving) would eliminate
exposure through containment only and ensure permanance by"
'implementation of a deed restriction. 'Alternative 5 (onsite
stabilization) would also be effective;in eliminating long-term 'risks "
by binding contaminants within the soil and then storing",th-is~°inateria'l,;'
in an appropriate mctnn:er. Alternative'2 (gravel cover.) would:'require '
an extensive long-term maintenance program to maintain' "adequate"';,::,
performance. ; ~~~, "
..' --.'
Reduction of Toxicity, Mobili~y"or Volume of the Cont"inants~Through..
Treatment I '"
~ . . .
Alternatives 4 (stabilization,' offsite landfilling) ands 'Cons:ite ,"
stabilization) would treat the sofls to reduce the toxicity', :mobility
or volume of the contaminants. Alternative JA (trea'tment: of:, "'hot.
spots," paving) would treat soils determined to pr:e$ent a"'princJpa'l;:,..
threat. 'Stabilization would reduce the mobility. of .the' ;contami:nants'~ ~>:; "
, although'the volume of the stabili'zedsoil would increase' JOto 5'0' ;.<.. .
. percent and toxicity would be unchanged. Alternative J (paving;) would:'.
! also reduce the mobility of 'site contaminants by, virtually eliminating.
dust g'eneration and vertical infiltration of precipitat:fon" .through the
degraded soil, although this reduction .would" still be les's' 'than! that '" ",
achieved by the treatment technologies.: Alternative: 2 (gravel cover) , ; . ~
would also reduce dust generation and direct: contact with~ c'ontaminated{'"
soils through placement of clean gravel; over :the degraded: soils' but: it,;" "
would do little to prevent' the vertical> migration of- precip'itat'ion. 'A" ,
more stringent air 'monitoring program ,wou'ld, be\req:u-fre'd 'to"ensure~,that '
dust generated: is not' contamina:ted,.,;, . ,,", '
Short-Term Bff8ctiveness'
Current Si~e conditions pose a long;-termrisk' to~ onslte'P and; nearby"
workers, .but the short-term risk 1s' low,. . Capping the S:i~te',' . , .
(AI ternati ves 2 and J) would reduce' exposures by inadver'tent": ingestion'
and inhalation and could be implemented in appropriately~ three months .'-:; :.
Excavation of "hot spots" and 'containing th,e remaining d'egraded soils ':-'
onsite (Alternative JA) could be implemented within J to 6 months. . '
Complete excavation, stabilization and off-or-onsite placement . ,
(Alternatives 4 and 5) would take between'6:and 12 months;' to complete.::.
29
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Because stabilization involves soil excavation and handling, some
increased risk from exposure. to dust exists, although dust-control
procedures would minimize these risks. Excavation of less volume
(Alternative 3A) would present less short-term risk.
Imp1ementability
All action alternatives would be technically feasible to implement.
Services, equipment, trained personnel and supplies are readily
available. No difficulties are anticipated for Alternative 3. . An
adequate gravel cover (Alternative 2) may prove 'difficult to maintain.
due to vehicular traffic. Long-term air monitoring associated with the
gravel cover alternative would be extensive because contaminated and
uncontaminated soils would be indistinguishable by visual inspection.
The excavation and transport of contaminated soils (approximately 5,200
cubic yards associated with Alternative 4 or 20 cubic yardsass~~~ated
with Alternative 3A) would require extra care during handling
activities; the smaller volume associated with Alternative 3A makes
this alternative less burdensome in this regard. Alternative 5 (onsite
stabilization) would be the. most difficult to design and construct'
. because of the earthmoving that would be required and the increased
volume associated with the treated material. .In addition,
identification of an.acceptable onsite location for construction of the 1
disposal unit may be problematic due to a relatively 'high water table.
Cost
CERCLA requires selection of a cost-effective remedy (not merely
the lowest cost) that protects human health and. the environment and
meets other requirements of the statute. Project cost includes all
construction, monitoring and maintenance costs incurred over the life
. of the project. An analysis of the present"worth value of these costs
has been completed for each alternative described in this Record of
Decision, and is summarized in Table 11. capital costs include those
expenditures necessary to implement a remedial action. Annual'.
monitoring and maintenance costs are included in the present worth
cost. The cost, in order of most to least, is Alternative
Nos. 4, 5, 3A, 2 and 3.
. community Acceptance
The proposed Plan was released to solicit public comment regarding.
the proposed remedial alternatives on October 15, 1990.' At that time a
30-day comment period was opened. A public meeting on the Proposed
Plan was held November 8, 1990, in Hanover,' Maryland. Comments raised
. at the public 'meeting and. received during the comment period are
summarized in the Responsiveness Summary which is .included in this
Record of Deci.sion. In general,. the public did not object to any of
the remedial alternatives. .
30
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Table 11
cost-comparative ADalysis
Kid-Atlantic Wood Preservers
Capital Annual Present
Cost O&M Costa Worth Costb
Alternative 1 $ 0 $ 4,000' $ 45,000
Alternative 2 189,000 11,500 318,000
Alternative 3 239,000 6,500 312,000
Alternative 3A 249,400' 6,500 3,22,400
Alternative 4 2,700,000 5,000 2,150,00'0, '
Alternative 5d ,944,000 12,200 1,080,000
" ,-.':
a 'The costs associated with long term surface water and sediment~;'
sampling are not included in this cost summary.
b A discount factor of 8 percent per year;'was assumed with annual 'costs. .
incurred for 30 years. ' ' .
, The costs associated with the treatment?of' highly contaminated :sorls~
are based on the unit costs developed :for Alternative 4.<' Since"'"
significantly smaller volumes of soil will be handled under '.
Alternative 3A, the unit cost will likely be substantially higher.
, ' '
d Costs associated with liner and cap installation~' are' .not' incTuded -,in:;
this cost estimate. '
II
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stat. Acceptance
The State of Maryland has concurred with the selected Remedial.
Action for this site.
IX.
THE SELECTBD REDDY
After consid'eration of the requirements of CERCLA and an evaluation
of the alternatives and public comments, EPA has determined, in
consult~tion with the State of Maryland, that Alternative 3A is the
most appropriate remedy for the Mid-Atlantic Wood Preservers Site.
Highly concentrated areas of contaminated soil .(greater than 1,000
mg/kg arsenic) will be excavated, stabilized and disposed of offslte in
a permitted RCRA disposal facility. Soils containi~ greater than 10
mg/kg but less than 1,000 ~g/kg arsenic will be contained in.place.
.. .
. The existing concrete drip pad will be expanded to approximately
79x91 feet and roofed (see Figure 12). The enlarged drip pad will be
designed to provide adequate area where freshly treated wood can drip
for at least 72 hours prior to its removal and will ~e in compliance
with new RCRA regulations for wood treatment facilities. The curbed
drip pad will be sloped such that drippings and incidental rainfall can
be collected in a sump pit and recycled into the treatment system.
Runoff water from the roof will be directed away. from the drip pad.
The expansion of the concrete drip pad will contain remaining
underlying degraded soils in place, significantly reducing the
potential leaching of contaminants, the generatic;m of airborne dust,
and human contact with contaminated soils beneath the pad.
An asphalt/concrete cap will be placed over those portions of the
Treatment Yard that will not be covered by the treatment plant,
enlarged drip pad, or currently paved parking area. Contaminated soi1
areas in the Storage Yard (exceeding 10 mg/kg arsenic) will also be
paved with an asphalt/concrete cap. Any contaminated soils that may
have eroded outside the perimeter of the facility, to be determined
during pre-design activities, will be consolidated under the cap. The
paving material will be selected during the remedial design. Figure 13
represents the locations of the areas of the different. actions.
~
. .
. .
The construction of 'an asphalt/concrete cap over the contaminated
soils will prevent direct contact with, and inhalation of, potentially
harmful dust generated from those soils, provide a durable cover that
will resist deterioration due to vehicular traffic, prevent upward
migration of contaminants from. the underlying gravel and soils, and
reduce the potential for leaching of contaminants from..the'soils to the
groundwater. In addition to the development and implementation of a
long-term maintenance plan, periodic air, surface water, sediments a~d
groundwater monitoring will be conducted to gauge the effectiveness of
the remedy. It is anticipated that monitoring frequencies, to be .
determined during the remedial design, will decrease with time should
conditions warrant; however, the long-term ~aintenance plan shall
remain unchanged. A deed restriction will be executed to ensure that
the containment components. are not compromised by future use of the
property.
II
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Because hazardous substances, pollutants or contaminants will'
remain at the site following remediation, a review of this remedial
action, including site inspection reports and air, groundwater and
surface water data, will be conducted no less often than each five
years after the initiation of this alternative as required ' under
section 121(C) of CERCLA, 42 U.S.C. S 9621(c).
, ,
The goal of this remedial action is to provide treatment of soils
determined to be a principal threat and prevent human c~ntact with.
soils containing greater than 10 mg/kg arsenic, thereby reducing risk
to within EPA guidelines. The additional carcinogenic risk associated
with no action at this Site is approximately 5. 7X10-4, after'
implementation of the selected remedy, carcinogenic risk wilL b~ less
than 1.0X10.s. The construction of an enlarged, roofed drip pad :and
modification of standard operating procedures consistent with' the new
wood treatment regulations is required to reduce the potenti~lfor
future releases of chromated copper arsenate to the environment. If,
prior to construction of the enlarged roofed drip pad, it is determined
that the site will not be used as a wood treatment facility the area
will" be capped with an asphalt/co'Jicrete cap after removal and treatment
of soil which is determined to present a principal threat (this~will '
reduce the cost of the remedy). .
The cost summary for the selected alternative is shown in Table' '12.'
It should be recognized that minor changes to the selected :alternative ~
may be made during the remedial design. These changes 'in general will:
reflect the usual modification resulting ~rom the engineerin~process
and will not reduce the effectiveness ;of the selected remedY.:::~, ,
x.
STATUTORY DETERMINATIONS
Under its legal authorities, EPA's primary responsi;billty~at, .'
Superfund sites is to undertake remedial actions:that .ac~ieve~adeqUate:
protection of human health and the environment. 'In add;ition, 'secti'on .
121 of CERCLA, 42 U.S.C. S 9621, establishes 'several other statutory'"
requirements and preferences. These specify that 'when :complete,,; the ,
selected remedial action for a site must comply with applicable for ;,.
relevant and appropriate environmental standards 'establ'lshed under '; '.
federal and state environmental laws unless a statutory, waiver is .
justified. The selected remedy also ~ust becost~effectiveand utilize'
permanent solutions and' alternative' treatment technolog;i'es or, :resource '.
recovery technologies to the maximumext'ent' practicable'.,' ,.FlnaTly:" the'
,statute includes a preference for remedies' that employ treatment' th'at'.,
permanently and significantly reduce the volume, toxicity: or mobility',.> '
of hazardous wastes as their principle element. The fol'lowing: sect:i'ons:
discuss how the selected remedy for this Site meets these, sta.tutory; , . ;,:
requirements. '.
Protection of Human Health and the Environment' . .
..
By treating the prin~ipal threat; preventing: human"(co,ntact'; with~: ': ,
degraded soils; constructing an enlarged, roofed'drip pad;: and":' . ,
modifying the standard operating procedures utilized at ~the'ex1.sting, :~, ."
facility, the selected remedy is protective of, human health and, the' .:
environment. The baseline risk assessment: determined that,,, current. site' ,
II
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Table 12
B.~ima~e4 Cos~ Summary for Selec~e4 Reme4y.
Mi4-A~laDtic Wo04 pre.ervers
capital Co.t
. Cost . .
Cost Item Quantity Unit Price (1990$)
A. Removal of Contami-
nated Soils:
- Excavation and 20 c.y. . 8/C~y. 200
Loading of Con-
taminated Soils
- Hauling, Stabali- 27 c.y. 328/c~y... 8,900
zation, and Dis- "
posal at a RCRA
Landfill (swell
1. 35 for so i l)
- Backfill Excava- 20 c.y. 20/c.y. 400
ted Area
B. . Site Preparation:
- New Drip Pad and 4 c.d. 3,200/c:d. ." - 12,800
-
Graveling Areas "
C. New Drip Pad:
- Concrete Slab 6,200 s.f. 6.0/s.f. 37,200
- Roof 7,210 s.f. 9.0/s.f. 64,900
D. Asphalt Cover:
1. Treatment Yard
Gravel 83 c.y. 10/c.y. 800
Placement 5,000 s.y. 1.44/s.y. 7,200
Bituminous Pav-
ing
- 4" thick 4,000 s.y. 9.0/s!y. ',.36,000
- 2" thick 1,000 s.y. 6.0/s.y. ':.6,'000
2. storage Yard:
Geotextile 1,933 s.y. 1.4/s.y. 2,700
Gravel 215 c.y. 10/c.y. 2,200
Placement 1,933 s.y. 2.9ls.y. 5,600
Bituminous Pav- 1,933 s.y. 8.0 s..y. 15.500
inq (3" thick)
Subtotal: 200,400
E.. Construction Contin-
gencies (10 Percent) 20,000
F. Design, Engineering, and Construction
Mariageme.nt 29.000
Total Capital Costs: $249,400
Abbreviations:
c.y. = Cubic yardi c.d. = Crew daYi s.f. = Square footi
s.y. = Square yard
34
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Table 12 (con't)
.8timated cost summary for Selected Remedy
Mid-Atlantic Wood Preservers
Operation and Maintenance
Present. ",
Annual Cost Worth Cost ;
Cost Item (1990 $/Year) (1990 $)
Drip Pad $1,000 $11,30,0
Paved Areas 1,500 16:,:900, :.:
"
Groundwater Monitoring 1,500 16:',;.90,0"
"
Air Monitoring 2.500 28. 100 ~ '
Total , $6,500 $73,200
(
:
. "
, '.
a
Annual cost incurred for 30 years.
Discount of 8 percent', assumed'.
, Note: Quantities and materials to be determined durincf;the,remediaL./
. design. Specifics used for cost ,estimation .only.' ' ' " "
"
-
. .
-
: ;"
35
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conditions pres~nt an unacceptable carcinogenic risk (5~7X10-4). The
Haz~rd Indices were below 1.0, indicating no non-carcinogenic health
hazard. After implementation of .the selected remedy, the carcinogenic
risk will be reduced to less than 1.0X10-s, which is representative of
background conditions. There are no increased short-term risks or
cross-media impacts (e.g., release of contaminants in the soil into the
groundwater) associated with the selected remedy. . Air, surface water
and groundwater monitoring will be utilized to confirm the
effectiveness of the action taken. .
compliance with Applicable or Relevant anc!Appropriate Requirements
The selected remedy will attain all location, action and chemical-
specific applicable or relevant and appropriate requirements for the
site.' The major federal and state ARARs pertaining to the selected
alternative are summarized below. .
Action-specific ARARs ~
A) Hazardous Substances
state of Maryland requirements contained in COMAR 26.13.01-26.13.10
pertaining to excavation, handling and disposal of arsenic contam~nated
soils [applicable].
Resource Conservation and Recovery Act (RCRA).-Subtitle'C
requirements for closuie and post closure (40 C.F.R. Part 264, Subpart
G) [applicable]. Action must comply with closure and post closure
requirements because degraded soils will be left onsite. The
asphalt/concrete cap and long-term groundwater monitoring will be
. developed, installed and maintained in compliance with the
'aforementioned regulations. .
RCRA Land Disposal Restrictions pertaining to hazardous or .
hazardous characteristic wastes (40 C.F.R. P~rt 268) [applicable].
Soils that are excavated foroffsite disposal must receive pretreatment
prior to final land disposal. Land disposal restrictions do not apply
to consolidation of soils within a contaminated area.
Wood Preserving; Identification and Listing of Hazardous Waste;
Final Rule; 55 ~ ~ 50,450 (December 6, 1990) (to be codified at
40 C.F.R. Part 260) [applicable]. Drip pad construction and soil
handling shall be in compliance with recently promulgated regulations
concerning wood preserving facilities and materials handling.
. Transportation and disposal standards (40 C.F.R.~Parts 262-.2.65)
[applicable]. Any shipment. of contaminated soils offsite must comply
with aforementioned regulation.
B) OSHA
Occupational Safety and Health Administration (OSHA) requirements
for workers ~t remedial action sites 29 C.F.R. Part 1910 .[applicable]
36 .
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C) Air
state of Maryland requirements contained in COMAR 26.11 Sections
.01, .02, .03, .05, .06 and .15 pertaining to emmisions of arsenic and
chromium contaminated particulates [relevant and appropriate].
Sufficient air monitoring must be undertaken to ensure that dust
generated during const~ction activities is in compliance with
established regulations. '
D) Well Construction
, state of Maryland requirements contained in COMAR26.04.043
(applicable]. Installation and abandonment of monitoring wells must be
in compliance with aforementioned regulations. '
state of Maryland requirements contained in COMAR 26.05.01
pertaining to the selection of well drillers [applicable].
E) storm Water Management
state of Maryland requirements contained in COMAR 26.09~02 '
pertaining to storm water management (applicable)'. Remedial action'
must be designed in compliance with the aforementioned regulations.
F) Erosion and Sediment control
"
state of Maryland requirements c~ntainedin COMAR 26.09;01:
pertaining to the control of erosion, and :sedimentation [applicable].,
An erosion and sediment control plan must be developed and implemented:
during construction activities. ' ,
" '
Chemical-specific:: .AltARs
~> ';
'. ,,'
<", ."
A) Groundwater
a) Maximum Contaminant Levels (MCLs) and :non-zero Maximum, "',
Contaminant Level Goals (MCLGs) contained'in 40 C.F.R.parts"'14.F'and:s,
143 (relevant and appropriate]. "
b) state of Maryland requirements contained ,in COMAR:,2i6.04.01'
pertaining to drinking water quality standards' [relevant:; and ' '
appropriate]. '
Remedial action must prevent ,the release of, ;newpoLl~utants 'fnto. 'the: '
ground and reduce potential leaching' of those :contaminants' into the ?,; , ,: ' ,
groundwater to achieve and maintain water quality 'that meets federal: '
and state drinking water standards. Natural a,ttenuation;, 'coup 1 ed- .wi th.". ',.
the facility modifications identified in the'se~ected remedy, should, . ~
result in ground water quality meeting federal and state drinking water
quality standards within three months of construction completion..;, ' '
3 The substantive requirements of these, .sections will' be 'compiled
with. However, in accordance with section 121 (e) of CERCLA, 4,2,
U.S.C. ~ 9621(e), permits are notre~ir.ed for onsite,activities.' ~'
n'
-------
B) Surface Water
a) Federal Ambient Water Quality Criteria (relevant and
appropriate].
b) state of Maryland f-equirements contained.. in COMAR 26.08.01
through 26.08.04 pertaining to water pollution regulations [relavant
and appropr iate] . .'
Surface water runoff may not cause or contribute to the excursion of
federal or state surface water quality criteria in Stony Run.
other criteria, advisories orquidance to ~
considered for this remedial actioD (TBC's)
Federal Executive Order 11988, Floodplain Management, 40 C.F.R.
. Part 6, Appendix A. Action must avoid adverse effects, minimize
potential harm and restore and preserve natural beneficial value.
Federal Executive Order 11990, Protection of wetlands, 40 C.F.R.
Part 6, Appendix A. Action must minimize destruction, loss or
degradation of wetlands and preserve and enhance the natural and
beneficial values of wetlands. The erosion and sedimentation plan must
consider potential impacts of storm water runoff into wetlands
associated with Stony Creek.
Cost~Effectiveness
The selected remedy is cost-effective because it has been
determined to provide overall effectiveness proportional to its costs
(Net Present Worth being $322,000). The selected alternative is the
least costly remedy which will effectively provide for treatment of the
prinicipal threat and achieve the remedial objectives for the Mid-
Atlantic Wood Preservers site. .
utilization of Permanent Solutions and Alternative Treatment (or
Resource Recovery) Technologies to the Maximum BKtent Practicable
(MEP) .
EPA and MDE have dete~ined that the selected remedy (Alternative
3A) repre~ents the maximum extent to which permanent solutions and
treatment technoloqies can be utilized- in a cost-effective manner for
the Mid-Atlantic Wood Preservers site. . Of those alternatives that are
protective of human health and the environment and comply with ARARs,
EPA and MDE have determined that this selected remedy represents the
best balance of the nine evaluation criteria and the statutory'
preference for treatment as a principal element.
. Although the selected remedy does not offer the degree of
permanence ~ither Alternative 4 or 5 (lOot excavation, treatment and
on-or-offsite disposal) would offer, the excavation, treatment and
offsite disposal of only those soils determined to present a principal
threat, coupled with an asphalt/concrete cap on the remaining degraded
38
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soils to prevent human contact, does offer a very high degree of long-
term effectiveness and permanence. The cap will be inspected and
maintained ~o ensure long-term effectiveness and a deed restriction
will be implemented to ensure permanence. The stabilization treatment
technology will not reduce the volume or toxicity of the waste
material; however, it will reduce the mobility of arsenic from the most
. highly contaminated soils (ar.senic is not very mobile). Due to the
small volume of soils to be excavated, the selected remedy poses little
increased short-term threat to site workers or nearby residents.
Alternative 3 and 3A are the easiest of the protective alternatives to
implement, and offer the greatest reduction in risk in proportion to
cost. The selected remedy (Alternative 3A) meets the statutory
requirement to utilize permanent solutions and treatment technologies
to the maximum extent possible. .
preference for Treatment as a principal Element
The selected remedy does satisfy the statutory preference for
treatment as a principal element. As stated in the preamble of the'
NCP, EPA expects that treatment will be the preferred means by which.
principal threats posed by a site will be addressed. The preamble
characterizes principal threats as "waste that cannot be reliably.
controlled in place, such as liquids, highly mobile 1Daterials (e'.g'~;,;
solvents), and high concentrations of toxic compounds (e.g., several:
orders of magnitude above levels that allow for unrestricted use and;' :
unlimited exposure)" (55 Fed. Egg. 8,703 (March 8,1990». The waste..
material found at this Site is neither liquid nor highly mobile;,
however, a hot spot of highly concentrated arsenic in surface soils has
been identified adjacent to the drip pad. The selected remedy includes
. a provision for the excavation, stabilization and offsite disposal. of'
soils containing greater than 1,000 mg/kg' arsenic, which have' been': '
determined to be a principal threat. Soils containing greater. than' 1'0
mg/kg but less than 1,000 mg/kg arsenic: can be reliably:controlled:In' ,
place, do not present a principal threat and will, accordingly', be", ;, ,
contained in place. The selected remedy is consistent with program ~ , :
expectations to treat principal ,threats and use engineering controls'
for wastes that can be reliably controlled ,in place. EPA andMDE have, :
therefore determined that onsi te containment,' coupled with' treatment :of, '.'
hot spots, is an appropriate remedial action.
XI. SIGIfIPICANT CHAIIGBS,';.
The Proioaed Plan was released for' public comment in::"October"'19:90'. .
The Propos" Plan identified Alternative 3:, containment only, as the ;
preferred alternative. In consultation wi'th EPA :headquarters,lt, was
determined that Alternative 3, coupled with the excavation, "
stabilization and offsite disposal (a component of Alternative'4T of
hot spots only, represents a better balance of the nine evaluation :. -
criteria and satisfies the statutory preference for treatment .of
principal threats. This hybrid alternative. is designated as ',:
Alternative 3A. . .
Alternative 3A offers a reduction in mobility through treatment and
increased' long-term effectiveness and permanence by eliminating the"
most highly contaminated wastes. The limited excavation',entail'ed _,will :.
39
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not reduce the short-term effectiveness or implementability as would
the larqe scale excavation and treatment alternatives (Alternatives 4
and 5). The additional cost associated with the selected remedy is
estimated at less ~han 1J% above the costs associated with. Alternative
3 .
~~. -
. ~. 0" 4"'
"" '( J. .:" <' .~
- - ,
- .
- -
40
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. ,
RESPONSIVBNBBS SUMMARY
. FOR TBB
MID-ATLANTIC WOOD PRBSERVERS SUPERFUND
. ANNE ARUNDEL COUNTY, MARYLAND
! '
December 1990
. ~
, '
,
..
SITB.
., .~~
',.
(
-------
RBSPONSIVENESS SUMMARY
POR THB
KID-ATLANTIC WOOD PRBSERVERS SUPBRPmrD
AJf1fB ARtnmBL COONTY I IlARYLAIID
TABLE OF CONTENTS
. ~ .1-.
~ . ":.
section
I. Introduction
. . . . . . . .
. . . .
. .. . .
II. Public Meeting Comments
. . .
. . . . . .
A. storm Water Runoff
. . .
. . . .
. . .
B. Drip Pad
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C. Deed Restriction
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D. Long-term Monitoring
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E. Community Awareness. .
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F. RI Approach/Findings
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III. Written Comments. . .. . .
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RESPONSIVENESS SUMMARY
'. POR. THE PROPOSED REMEDIAL ACTION AT THE
MID-ATLANTIC WOOD PRESERVERS SUPBRPUHD SITE
ANNE ARtJNDEL COUNTY, MARYLAND
1.
INTRODUCTION
In accordance with the U.s. Environmental Protection
Agency's (EPA) community relations policy and guidance, the EPK
Region III office held a public comment period from October 15,'
1990 through November 14, 1990, to obtain comments on the'
Proposed Remedial Action Plan for Mid-Atlantic Wood Preservers'
Superfund Site in Anne Arundel County, Maryland. The remedial 0
action addresses onsite arsenic-contaminated soils and.
modification of the existing facility to prevent any future
release ofchromated copper arsenate wood treating solution. On
November 8, 1990, EPA and the Maryland Department .of the.
Environment (MDE) held a public meeting to obtain public ,comments
on the remedial investigation (RI), feasibility study (FS). and .<..
the proposed, remedy. Approximately 30 people attended the 'public ~,
meeting. Site information repositories contain the RIfFS, report,,:.!.,
Proposed Plan and other relevant documents. EPA maintained
contact with local officials and citizens throughout the remedy
selection process.
At the time of the public comment period, EPA's recommended
alternative addressed soil and groundwater contamination by
proposing to pave contaminated soils areas :with asphalt or
concrete; construct an enlarged, roofed drip pad in compliance' ': '.. .
wi th new RCRA regulations'; allow natural attenuation of ' . .
groundwater contamination; conduct long-term air and groundwater:",.
monitoring; and implement deed restrictions. The selected" ,...
remedy, Alternative 3A, adds a provision for the excavation,'"
stabilization and offsite' disposal of, highly contaminated soils:'~
(containing greater than 1,000, mgfkg' arsenic).
, ,
The selected alternative invo'l ves. enlarging the existing: ,. .,'
drip pad to approximately 79 x' 91 f.eet: 'and covering the :entire",,',
pad with a roo'f. Prior t'o expanding-,the'drip ,pad, soils:" '...
containing greater than 1,000 mg/kg arsenic must be. delineated, ".':-, , :"
excavated, stabilized and disposed offsite:. The excavated area ,""/ >
will then be backfilled with cle.an filIi. The expansion of the ,"v""
concrete drip pad would, in effect, contain, the remaining,
contaminated soils area with a low-permeability cap. This cap .
would reduce the potential leaching ',of :contaminants, the' ~',
generation of airborne dust and human' contact with contaminated' ':
soils beneath the pad., The dripped chemicals and limited ..
precipita~ion on the pad would be collected in'a properly lined'::
sump pit and recycled.
: ...
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'- .
.An asphalt or concrete cap would be placed on the remaining
portions of the treatment yard which would not be covered by the
treatment plant, enlarged drip pad, or currently paved 'parking
area. Contaminated soil areas in the storage yard would also be
paved with an asphalt/concrete cap. Any contaminated soils that
may have eroded, outside the perimeter of the facility would be
consolidated under the cap.
In addition to a long-term maintenance plan, periodic air
and groundwater monitoring would be conducted to gauge the.
effectiveness of the remedy. Deed restrictions would be
implemented to ensure that the containment components of the
remedy would hot be compromised by future use of the property.
All comments received during the public meeting and in"',:..: ,
writing are documented and summarized in this Responsiveness'
Summary. Section II presents a summary of questions and comments
expressed by the public at the November 8 public meeting.
Section III then contains a summary of written comments received
during the comment period. All questions and comments are
grouped into general categories, according to subject matter.
Each question or comment is followed by EPA's response. ,
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II.
PUBLIC MEETING COMMENTS" '
--
. 4'"t,.".
A.
storm Water Runoff
Several attendees expressed concern over the potential
impact of the increased volume of storm vater runoff that
vill be generated as a result of pavinq large portions of
the site. It vas stated that the area already has flooding
problems, partially due to storm vater runoff from the
Baltimore-..shington International (B.I) airport, and that
extensive land development is expected over the next several
years. '
EPA Response: The selected remedy will result in the paving
of approximately two acres. EPA will notify and cooperate
with the Anne Arundel County Department of Public Works
prior to initiating the paving activities to ensure .
compliance with any local storm water management '
requirements.
A resident, ,referring to the fact that storm vater
runoff from the eastern ~arcel flovs to a storm drain
located on Shipley Avenue, 'asked if the storm drains vere
used to discharge the" contaminants.
EPA Response: ~o; however, some exposed surface soils can
be transported (eroded) by storm water runoff into the
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drains. Sampling of surface' sO,ils near the storm sewer'
identified arsenic concentrations above background.
Implementation of the selected remedy will prevent the
continued erosion of degraded soils.
AD attendee recommended that concrete be installed on
the entire property and concrete retention basins be '
constructed to hold all site runoff.
EPA Response: All drippings will be collected on the
'expanded, roofed drip pad. Only wood that has been allowed; ~
to dry for a minimum of 72 hours will be removed from the
drip pad. Therefore, surface runoff from the long-term
storage areas will not be contaminated and mandatory
collection is not justified.
B.
Drip Pad
A resident asked where the drippings go.
~, .
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EPA Response: The drippings land on the concrete drip: pad."" '" ,
Any liquid that falls on the drip, pad drains back into the':, 0-
building where it is recycled back into the process. :
A resident asked if the drippings go back int~:the
building.
EPA Response: Yes. Drippings that land on the drip pad
, flow back into the building and into a sump pit.- It is :
pumped out of the pit and recycled back into the,~'storaqe"
tank. '
The producer of the copperchromated solution:, '
recommends that the wood be allowed to dry for '48 to 72" ':
hours before it is removed from the 'drip pad to prevent" ~':,'
potential leaching of solution constituents from the' ,freshly', ;; ,;
treated wood. CUrrently, based on the company's maximum ' .~.
production capability during a 72 hour period, there is not: ..: '
enough space to keep the treated wood on ',the drip pad, 'long' : "
enough. The selected remedied action includes the .. ,
construction of an enlarged roofed drip pad that wi'll be');, ,
large :enough to' safely handle the peak volume.;; The<"roof:" '
will minimize the volume of precipit.ation fall:ing.on th'e:",
p~. "
ODe attendee noted that the',wood treating operation ': ..: "
requires that all liquids that drip 'o-tf the wood be " '
collected in a swap pit'.' Be wanted'dto know:the capacity"of:"",
the storage tank that rece1ves this,cucess ,;solution:.: :"d, ':,~: '
, ,
EPA Response: There are two tanks;, '12,000 and 10;,,'OO,O~, "
gallons, respectively.
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A r..ident a.ked BPA what will happen if one of the
.torag8 tank .pring. a leak.
EPA Response: The interior of the building is basically a
containment system capable of managing leakage.
A re.ident asked what would be, placed around the drip
pad to contain the drippings. ' -' .~, ,',
EPA Response: A curb will be placed around the drip pad to
make sure that nothing flows off of it. The ~odified drip
pad, with a roof, a curb and a swale, will be constructed in
compliance with the new regulations governing drip pads at
wood preserving facilities.
AD attendee asked if the curb will be high enough to
prevent overflow in cases of extreme .fJ.Dod aDd:. wind'
conditions. '
EPA Response: Yes. These
during the remedial design
that the pad be capable of
event.
types of'. details will be defined
phase. The regulations require
handling a 24~hour, 25-year storm
A commenter asked what would happen to the Site should
Mid-Atlantic Wood Preservers file for.~Dkruptcy. ,-
EPA Response: EPA would likely access the .superfund to "
implement the selected remedy. Principal threats would be
excavated, treated and disposed of offsite.and soils
containing greater than 10 mg/kg but less than 1,000 mg/kg
, arsenic would be contained in place. " The long-term
maintenance and monitoring would remain unchanged. The
appropriateness of enforcement action would also be
evaluated. The remedy would not likely include, under these
circumstances, expansion of the drip pad. .
c.
Deed Re.triction
A re.ident a.ked who.e deed would be restricted and
whether the re.triction will be legally enforceable.
EPA Response: Mr. Liedman's, the owner of the facility.
The property records will contain a document restricting use
of the property in a manner consistent with the selected
remedy. '
D.
Long-term Monitoring
A re.ident wondered who would be doing the long-term
moni t.oring.
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EPA Response: Assuming a settlement is reached, 'the owner
will hire an environmental consultant to perform the long-
term monitoring with EPA and MOE performing oversight.
There' will be a long-term monitoring and maintenance plan
approved by EPA and the owner will have to implement that
plan.
A review of this remedial action, including site
inspection reports and air, groundwater and surface water
data, will be conducted no less often than each five years
after the initiation of this alternative as required under
Section 121(c) of CERCLA, 42 U.S.C. S 9621(c).
. .
A resident asked why BPA couldn' t perform the:.:Iong-
term monitoring. ~"" .'
EPA Response: The statute obligates EPA to give the, .
responsible party the opportunity' to conduct the long-ter~
monitoring. However, EPA is also charged with the. ,
responsibility of ensuring that the work is being unde~taken
in compliance with the terms and conditions of the resultant; '.:.'
consent decree and the Record of Decision. ' , ' .'
A resident wanted to know how long the deed restr'iction
!and lonq-term monitoring will ~e .in.effect.
, '\~
EPA Response: The long-term monitoring will be in' effect as. ,
long as it is appropriate. The 'deedirestriction would be'
attached indefinitely. ' '
.'
B.
community Awareness
:~ ..
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A resident asked if it was' possible to hOld'a,m.eting;::'
to discuss the remedial designs. .' .' "
EPA Response: An informal meeting: to discuss thedesigns/c,
once they are complete will. be scheduled into the':Community~ ~
Relations Plan. . '
.""
The site vas finali.ed on:'the' IJPL:. in. '198':ra';'resid'ent'.;<.,
asked wby tbe r..edy selection,' process (, took'so.'loDg..;. ",'
The process requires that we; evaluate the':universe..of:' "
possibilities forremediating the site. First".jwe have~:-to:. .
identify and evaluate any potential risks ,not 'just ,those '<,..':
that were identified in the site Investigation which ledto::\
the Site being listed on the 'NPL.:. . Then each poss'lble .means."
of reducing the' risk 'presented. to "human.healthand',the. ' "'.>
environment is evaluated: using the, nine !.criteriaIiidentif'ied
in the NCP. '
..;
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A reai4ent aske4 who is paying for the coat of
perforaing the site evaluation.
EPA Response: CERCLA establishes several categories of
persons potentially responsible for response ,costs incurred
by EPA. In this instance, Mid-Atlantic Wood Preservers,
Inc. is a potentially responsible party and may be required
to reimburse EPA for its response costs. MAWP has, pursuant
to a consent order with EPA and MDE, financed and performed
the RIfFS. .
Some attendees expressed concern that ~hey were
insufficiently informed a~outthe site activities. .
EPA Response: The community relations plan will be rescoped
to ensure that it meets the informational needs of the
community.
P.
..
RI Approach/Pindings
A resident asked if the community i8 using "county
Water". .
EPA Response: Yes. Everyone in the area',is, 'linked to the
Anne Arundel County public water supply. In addition to
public water, Mr. Hall maintains a private well which is
screened at approximately 60 feet and used by Mr. Hall for
lawn watering. Samples taken by MDE have revealed no ",:
contamination. -
- AD attendee asked if sediment and. water samples were
taken from stony RUD.
EPA Response: Yes.
background ranges.
And they were all within the normal
AD attendee asked what is the depth of 80il
contamination.
EPA Response: ' The contamination is confined to the surface.
Soils were sampled at 0-0.5 feet, 3-3.5 feet and at the
groundwater table. . All elevated concentrations, with one
exception, were found in the 0-0.5 feet range. Every sample
taken deeper than 3-3.5 feet was at background
concentrations. One sample that was taken adjacent to the
current drip pad, 3-3.5 feet, had a level of arsenic that
was greater than 10 mg/kg arsenic. -
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An attend** asked if off-sit* soil samples were taken.
EPA Response: Soil samples were taken from a single
location on Mr. Edward's property and a single location on
Mr. McLean's property, both topographically downgradient of
the Site, revealing concentrations at background levels.
Pre-design activities will include sampling around the
perimeter of the facility to identify any degraded soil that
may have eroded outside the facility.
A resident asked how far downstream the stony Run
discharges into the Patapsco River.
EPA Response: Four miles.
An attendee asked if EPA was satisfied with ten wells.
EPA Response: Yes. Especially given the size of the
facility (-3 acres). Ten wells give EPA a high degree of
confidence that any groundwater quality problem would have
been identified if it was present.
An attendee asked if the groundwater was tested for
pollutants other than arsenic and chromium.
EPA Response: Four of the ten wells were screened for the
full Total Analyte List, and Target Compound List, in
addition to cyanide and the pH level. The remaining six J
wells were sampled for chromium/ copper, arsenic and; the pH
level.
; A resident asked if EPA selected Alternative Three
because it provided maximum protection to the community from
exposure to sit* contaminants.
EPA Response: Alternative three meets the defined remedial-
objectives, and it balances favorably against the other
alternatives with respect to the;nine-evaluation criteria. •
III. WRITTEN COMMENTS. • •'. , --
The United states Department of the Interior (DOI)
not*4 that although onsite soils contamination is not a ''
significant pathway to its trust resources, th«r* remains 'a
possibility that storm water runoff and degraded groundwater
could potentially impact the waters and sediments of stony
Run and create a pathway to DOI'a trust: resources [migratory
birds, anadromous fish, and the swamp pink (Helonias ;; :.
bullata)1. DOI stated that their concerns would be ""
adequately addressed if the selected remedy included
provisions for monitoring the surface water and sediment.
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,.";
EPA Response: Surface water and sediment sampling results
evaluated during the remedial investigation suggest that
stony Run is not currently being impacted by conditions at
the Mid-Atlantic wood Preservers Site. Further, the
selected remedy is expected ~o improve the water quality of
storm runoff by preventing new releases of ch=omated copper
arsenate and erosion of existing degraded surface soils.
However, given the historical data indicating that Stony Run
has been impacted in the past and that storm water runoff
will continue to be discharged into the Stony Run flood
plain, a provision requiring long-term surface water and
sediment monitoring has been included as part. of the
selected. remedy. '
The united states Fish and Wildlife service (service)
questioned the accuracy of SPA's assertion that the
unvegetated, chain-link fence enclosed wood preserving
facility does not provide habitat to wildlife. The service
stated that transient use by migratory birds is available
and does occur.
'"
EPA Response: . It is accepted that transient use by
migratory birds may actually occur; however, EPA agrees with
DOI that onsite soils contamination is not currently a
significant exposure pathway to wildlife. The
implementation of the selected remedy will further reduce
the potential impact of site soils on wildlife. '
The u.s. Fish and Wildlife Service ~ote that the
statement about offsite sediment not being degraded is
premature. The Service strongly supports offsite sediment
sampling.
EPA Response: A provision for surface water and sediment
monitoring has been included as part of ,the selected remedy.
In addition, soil sampling around the perimeter of the
facility will be undertaken to confirm that degraded soils
have not eroded offsite.
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DEPARTMENT OF THE ENVIRONMENT
2500 Browing Highway, Baltimore, Maryland 21224
A/taCod*30l • 631- 3304
Roberc Perciasepe
WUtem Ootufd SchMfer MUM JMUMflUKXttX
a°"*mor Svcrvtvy
December 28, 1990
Mr. Thomas C. Voltaggio
Acting Division Director (3HWOO)
Hazardous Waste Management Division
U.S. Environmental Protection Agency
Region III
841 Chestnut Building
Philadelphia, PA 19107
Dear Mr. Voltaggio:
The Hazardous and Solid Waste Management Administration (HSWMA) has
completed its review of the Record of Decision for the Mid-
Atlantic Wood Preservers Site. HSWMA concurs with EPA 'a selected
remedy, alternative 3-A which involves excavation, stabilization
and off-aite disposal of any soils containing greater than ;1,000
mg/kg arsenic. Soils containing greater than 10 mg/kg but less
than 1,000 ng/kg arsenic would be contained in place. This will
require paving contaminated soil areas with asphalt/concrete,
constructing a roof and enlarging the drip pad, conducting long-
term monitoring, and implementing deed restrictions.
We look forward to continuing our cooperative relationship with EPA
on this project as we implement remediation at this site.
incerelY
Richard W. Collins
Acting Director
Hazardous and Solid Waste
Management Administration
RWC:klj
cc: Mr. James Pittman
Mr. Frank Henderson
Mr. Thomas Andrews
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