United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R03-90/102
September 1990
EPA Superfund
Record of
Tyson Dump #1, PA
-------
50272.101
REPORT DOCUMENTA11ON 1" REPORTNO. I ~ S. A8cIpIent8 AcC88810n No.
PAGE EPA/ROD/R03-90/102
4. TItle end s..b1I1I8 So A8pw1 Da18
SUPERFUND RECORD OF DECISION 9/28/90
Tys on Dump # 1, PA
Third Remedial Action II.
7. AUlllor(8) II. Pwformlng Organlzadon R8pL No.
8. Pwformlng OrgaIniDdon ...... end AddN88 10. ProjltcllT8IiIIWorII Unit No.
1 t. ~ct(C) 01 Gt8lll(G) No.
(e)
(G)
12. Sp-..ring Orgeniutlon ...... end Addreu 1 S. Type 01 Report , Period Co-
U.S. Environmental Protection Agency 800/000
401 M Street, S.W.
Washington, D.C. 20460 14.
15. Suppf8m8nt8ly No,..
t 8. Abetr8ct (UnlIt: 2110 -..)
The 4-acre Tyson Dump '#1 site is an abandoned septic and chemical waste disposal area in
Upper Merion Township, Montgomery County, Pennsylvania. The site consists of a series
of abandoned unlined lagoons in a former sandstone quarry, and is bordered by unnamed
tributaries to the Schuylkill River on the east and west, and a railroad switching yard
to the north. Beyond the railroad yard is a floodplain/wetlands area and the Schuylkill
River, which flows southeast toward Philadelphia. The river is the main source of
drinking water in the area. Barbadoes Island lies in the center of the river in the
site vicinity and is used as an electrical substation. From 1960 until 1973, the
privately owned site was used for the disposal of liquid septic tank wastes, sludges,
and chemical wastes that were hauled onsite in bulk tank trucks. In 1973, the State
ordered the site owner to close the facility. In 1983, EPA required that immediate
removal measures be taken, including constructing a leachate collection and treatment
system with drainage controls, covering ,the site, and implementing site access
restrictions. In 1984, the first Record of Decision (ROD) for the site was issued for
Operable Unit 1 (OU1), which documented a remedy that included excavation and offsite
disposal of lag~o;rnaterials. In 1988, a second ROD was signed, which documented a
,
(See Attached Page)
17. Doco.ment An8fy8I8 .. D88atp8oIa
Record of Decision - Tyson Dump n, PA
Third Remedial Action
Contaminated Medium: gw
Key Contaminants: VOCs (toluene and xylenes)
b. IdentHl8r8/Op8n-&lc T-
Co COSA n Fl8lcl/Grcql
18. A¥IIII8bl1ty St8I8mInI II. 98curttr a- (TIde A8port) 21. No. of PI/I88
None 68
2D. 98curttr era. (ThIs Pege) 22. PrIo8
Non~
272(~77/
(See AI$.Z3I.18)
See~_onllt-
(Fonnorfy ~)
~t of Commerce
-------
EPA/ROD/R03-90/102
Tyson Dump *1, PA
Third Remedial Action
Abstract (Continued)
remedy for treating the ground water contamination under the offsite areas (OU2),
including the railroad yard and wetlands areas, using steam stripping followed by
liquid-phase carbon adsorption as a polishing step. This third ROD addresses OU3,
the further remediation of the contaminated ground water that has migrated under the
Schuylkill River. Additional qround water investigations will be conducted on the
north side of the river, and based on the results, a fourth operable unit may be
identified. The primary contaminants of concern affecting the ground water are VOCs
including toluene and xylenes.
The selected remedial action for this site includes installing additional recovery
wells on the south bank of the Schuylkill River and on Barbadoes Island, followed by
treating the contaminated ground water at the existing treatment facility on the
south bank of the river; expanding the capacity of the existing treatment facility;
investigating hydrogeologic conditions on the north side of the river to assess
environmental impact and the need for additional RODs; and implementing institutional
controls to restrict ground water use. The estimated present worth cost for this
remedial action is $10,100,000, which includes an annual O&M cost of $834,000 for 30
years.
PERFORMANCE STANDARDS OR GOALS: Discharge limits for treated ground water were
calculated by the State based on risk factors, dilution within the river, and State
and Federal standards. These limits are toluene 1.52 mg/l (based on a chronic WQC of
0.33 mg/l) and xylenes 0.97 mg/l (based on an MCL of 10.0 mg/l) .
,
-------
Declaration
por The
aecord of neci.ion
site Name and Location
Tyson's Superfund site
Upper Merion Township, Montqomery County, Pennsylvania
Operable Unit Three
statement of Basis and Pureose
This decision document represents the selected remedial
. action for the Operable Unit Three at the Tyson's Superfund Site,
in Upper Merion Township, Pennsylvania, developed in accordance
. with the comprehensive Environmental Response, compensation and
Liability Act of 1980, as amended by the Superfund Amendments and
Reauthorization Act of 1986 (SARA), 42 U.S.C. S S 9601 et sea.
and, to the extent practicable,. the National contingency Plan
(NCP), 40 C.r.R. Part 300. This decision is based on the
Administrative Record for this site.
The Commonwealth of Pennsylvania has concurred on the remedy.
Assessment of the site
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action
selected in this Record of Decision, may present an imminent and
substantial endangerment to public health, welfare, or the
environment.
DescriDtion of the Remedv
This remedy,addresses containment and remediation of contaminated
ground water by reducing the risks posed by the site through
engineering and institutional controls.
The selected remedy includes the following major component~
o
Installation of six additional recovery wells on the
80Uth bank of the Schuylkill River, expanding the
existing interim ground water recovery system from
seven recovery wells to thirteen recovery wells.
Installation of ground water recovery wells on
Barbadoes Island, unless a more suitable location for
pumping ground water is determined during the design of
this remedy.
o
I
/
-------
o Construction of a pipeline, if necessary, beneath the
Schuylkill River to transport contaminated ground
water, pumped from Barbadoes Island, or more suitable
locations as determined during design, to the existing
treatment facility located on the south bank of the
River.
o Investigation of hydrogeologic conditions on the north
side of the Schuylkill River.
o Operation and maintenance of the ground water recovery
system and ground water monitoring, for 30 years.
6 Initiation of institutional controls restricting ground
water use on Barbadoes Island and on the north side of
the river within the contaminated groundwater plume.
Statutory Determinations
The selected remedy is protective of human health and the
environment, attains Federal and State requirements that are
applicable or relevant and appropriate, and is cost-effective as
set forth in Section 121(d) of CERCLA. 42 U.S.C. § 9621(d) and
Section 300.68 of the NCP. This remedy satisfies the statutory
preferences as set forth in Section 121(b) of CERCLA, 42 U.S.C.
§ 9621(b), for remedies that employ treatment that reduce
toxicity, mobility or volume as a principle element. Finally, it
is determined that this remedy utilizes permanent solutions and
alternative treatment technologies to the maximum extent
practicable.
Because this remedy will result in hazardous substances remaining
in the ground water, a review will be conducted within five years
after commencement of remedial action to ensure that this remedy
continues to provide adequate protection of human health and the
environment.
Edwin B. Erickson Date
Regional Administrator
Region III
-------
flit* Description anq gMngarv °f Rem
Alternative fleleetiop for the
Tyson's fluperfflad flit*
Montgomery Count. P
Site Location and Description
The Tyson's Superfund site is an abandoned septic waste and
chemical waste disposal site located in Upper Merion Township,
Montgomery County, Pennsylvania (Figure 1) . The approximate 4-
acre plot, which constitutes a series of former unlined lagoons
in a former sandstone quarry, is bordered by unnamed tributaries
to the Schuylkill River on the east and west, a steep quarry high
wall to the south, and a Conrail railroad switching yard to the
north. The site is surrounded by residential areas to the south
and west. The former sandstone quarry was apparently excavated
into weathered and fractured bedrock along an east-west treading
ridge, forming two bowl-like depressions divided by a bedrock
ridge into eastern and western sides. The excavation can be
described as a large eastern pit and a less well-defined western
excavation that consists of a series of low benches. A high wall
of up to 40 feet separates the former lagoon area from the
Conrail tracks to the north, while the high wall to the south of
the former lagoon area is as high as 100 feet above the former
lagoons.
The Schuylkill River is the main source of drinking water in the
area and supplies Norristown and parts of Philadelphia with
intakes down river of the site. The River also has recreational
uses including fishing and boating. Except for a couple of wells
located upgradient from the site and in Norristown, groundwater
is not used as a potable source in the area surrounding the
Tyson's site. Groundwater flow is North towards the river.
The Schuylkill River flood plain and the wetlands area is located
north of the Conrail tracks and lies within the 100-year
floodplain. Barbadoes Island is situated in the middle of the
Schuylkill River directly north of the site. A former coal-
fired electric power generating station operated by the
Philadelphia" Electric Company (PECO) currently occupies the
island. The facility is currently used for company training, for
equipment storage, and as an electrical substation.
The Township of West Norriton and the City of Norristown are
located on the north side of the river. These areas are
primarily residential and light commercial with some small
manufacturing facilities.
Site History and Enforcement Activities
From 1960 to 1970 the site was owned and operated first by
unincorporated companies owned by Franklin P. Tyson and then by
-------
rigure 1
Location Map
Tyson's Site
-------
Fast Pollution Treatment, Inc. The stock of this corporation was
owned by the current owner of the land, General Devices, Inc.
(GDI), and by Franklin P. Tyson. GDI was active in the
management of Fast Pollution Treatment, Inc. The site was used
for disposal of liquid septic tank wastes and sludges and
chemical wastes that were hauled to the site in bulk tank trucks.
The major responsible parties using the site for disposal were
Ciba-Gcigy Corp., Wyeth Labs Inc., Smith, Kline, Beckman Corp.,
and Essex Group Inc. It appears that as the lagoons were filled
with wastes and subsequently covered, new lagoons were created.
In 1969, the property was purchased from Fast Pollution
Treatment, Inc. by GDI. In 1973, the Pennsylvania Department of
Environmental Resources (PADER) ordered the site owner, GDI, to
close the facility. During closure, the lagoons were reported to
be emptied of standing water, backfilled, and vegetated and the
contents transported off site.
In January, 1983, EPA investigated an anonymous citizen complaint
about conditions at Tyson's and subsequently determined that
immediate removal measures were required. These measures
included the construction of a leachate collection and treatment
system, drainage controls and cover over the site, and the
erection of a fence around the site.
Between January 1983 and August 1985, the U. S. Environmental
Protection Agency (EPA) and its subcontractors conducted a series
of investigations, primarily in what has been referred to as the
on-site area. The on-site area was defined as the area south of
the railroad tracks and within or immediately adjacent to the
security fence erected during the emergency response measures
(Figure 2). The on-site area encompasses the former lagoons.
The Tyson's site was placed on the National Priorities List on
September 21, 1984. In December 1984, EPA issued its Record of
Decision (ROD) for the on-site area. The ROD selected excavation
of the materials in the former lagoons and off-site disposal of
these materials.
s
Following issuance of the ROD, EPA began remedial design for the
selected alternative in January 1985. This design included
additional borings throughout the lagoon area to define the
volume of material to be excavated. In August 1985 through
November 1985 EPA performed additional borings and magnetometer
surveys throughout the lagoon area to better delineate the areas
to be excavated.
In the fall of 1985, Ciba-Geigy Corporation agreed to conduct
further investigations of the off-site area, the need for which
was described in the December 1984 ROD. The off-site area is
defined as the area outside the security fences that surround the
former quarry dump site, including the deep aquifer (bedrock
aquifer). The off-site area was subdivided into five sub-areas
-------
Figure .2,
O"-811e perable Units
Tyson's Site
SdII,U 1Ii~
""~"~~I~II""'~.,~~~ ~
...,-,1 . - -~"I~-
\ ~ "'~I ~ Ji~«.,
\. '..~ ~~
-- ~~
~ ....a..... ......... . ~
-- . 1- ---
~ --..:==-~~-:;.~-- '..~
' - - :"""""11..--..:-'- - .... -..... -- . . '.
\ qo:--~- - - =-~a:..~~-;.c:- .'
~ .~~~-~/~G-~~~~:;;r--- ...;' ')., ,~
~ ~ "..,-, -- - .
'J
C~""""""""""""""""""""""""""III#IIIIII~
\
~ RIIIInMId -.
\ . . ",
. .. ~'-' -~.. "
\ , .111.1. ~,,,4,U.~. L.oc88IDn, ...." I
~ \ ~ ".~~ :~-,
~..... '! ,-~.P (?J - -r 0. ~T - '" ~ '-', ,
' .~~ ':-1itfJ ,--~~ / "" -./.--
~""""'_'_~_~~-:'''' It - --- // \..~",-
- - -=:=... ~ . .~ "-...........
. I;' s.; ~ -- - ...1...................
I'" .
': .
II
h
,
EXPlANATION
----- Tpan". On-Sle 8aund8ry
o
100
Scale in feel
-------
5
(Fiqure-2), including the Deep Aquifer, Hillside Area, Railroad
Area, Floodplain/Wetlands and Seep Area.
In March 1986, Environmental Resources Management, Inc. (ERN)
prepared and submitted to EPA Region III on behalf of Ciba-Geigy
a draft of "The Work Plan for Remedial Investigation /Feasibility
study of Tyson's Site Off-Site Operable Unit." The final work
plan was attached by EPA Region III to an Administrative Consent
Order (ACO), siqned byEPA and Ciba-Geigy corporation on May 27
1986. Prior to submittal of the final version of the work plan,
EPA granted Ciba-Geigy and ERM permission to conduct certain
tasks of the Off-Site Operable Unit Remedial Investigation/
Feasibility Study (RI/FS) before the effective date of the ACO.
Activities completed durinq this time have been termed "interim
work" and consisted of monitorinq well installation, testinq, and
sampling.
Based upon field observations during drilling and samplinq and
the analysis of ground water samples collected during the interim
work, it was evident that the work as detailed in the March 1986
Work Plan would have to be amended prior to the completion of the
Off-Site Operable Unit Endanqerment Assessment (EA) and FS. The
first Addendum to the Off-Site Operable Unit RI/FS Work Plan was
prepared by ERN and submitted to EPA in July 1986. The scope of
work for the first addendum included the installation of
additional monitoring wells. Schuylkill River water and
samplinq, r8.idential and community well sampling on the
side of the River, dense nonaqueous phase liquid (DNAPL)
and additional soil borings.
In November 1986 Ciba-Geigy Corporation initiated an on-site
pilot study u.ing an innovative vacuum extraction technology
process. Due to zoning restriction., the pilot study operated
for only a .hort duration (less than 10 days). However, in May
1987, the pilot .tudy was permitted to operate for more than
three weeks.
sediment
north
testinq
On December, 8, 1986, ERM submitted to EPA the Draft Off-Site
Operable Unit RI and EA Reports for the Tyson's site. These
reports pre.ented the results of the investigation a. originally
detailed in the initial work plan and the first addendum to the.
work plan. ".ed on the results and conclusions of the Off-Site
Operable Oni~ RI and EA, it was recommended that the selection of
the potential r..edial measures for the Hillside Area, Railroad
Area, Floodplain/Wetlands Area, and the Seep Area Operable Unit
be addresaed in the Off-Site Operable Unit Feasibility Study
(FS), However, regarding the deep aquifer and schuylkill River
it was recommended that additional tests be conducted prior to
assessing potential remedial measures. The Off-Site Operable
Unit FS did address alternatives for the portion of the deep
aquifer which extends under the on-site area to the aouth bank of
the Schuylkill River.
-------
6
On March 24, 1987, a second addendum to the off-site RI
work plan va. submitted to EPA by Ciba-Geiqy corporation. This
addendum included a detailed investigation of the schuylkill
River and the installation of wells on the north side of the
river.
On July 29, 1987, Ciba-Geiqy corporation submitted the final
draft operable Unit. RI report to EPA which included the results
of the second addendum.. Tnis report concluded that much of the
site contamination, specifically the dense non-aqueous phase
liquids (DNAPLS), were in the underlying bedrock and aquifer.
The report also found that a dissolved portion of the DNAPLs was
discharging into the Schuylkill River.
In June and July 1987, four responsible partie., Ciba-Geiqy
Corporation, SmithKline Beckman, Wyeth Laboratorie., and Essex
Group .ubmitted a proposal to EPA for clean-up of the on-site
(lagoon) area., upgrading of the leachate collection system and
cleanup of the tributary sediments. Additionally, the parties
propo.ed to initiate groundwater remediation .ea.ure. since the
information contained in the draft Oft-Site Operable Units RI
report indicated that much of the contamination formerly in the
lagoon area. va. now in the aquifer syst.., down gradient of the
site, and was di.charging to the schuylkill River.
The partie.' propo.al was based on a Comprehensive Feasibility
Study (CFS) .ubmitted to the Agency on June 15, 1987. The CFS
was developed independently by Ciba-Geiqy corporation and was not
formally co...nted on by EPA. The CFS incorporated the results
of the innovative vacuum extraction proce.. for clean-up of the
lagoon .oil., preliainary result. of the Off-Site RI and
additional .tudie. for the installation of groundwater recovery
well.. Some of the re.ults of the CFS indicated that the
contaminant. in the bedrock underlying the lagoons would be a
source of continuing contamination of backfilled soil' used to
replace .0il'8 excavated pursuant to EPA'. ROD. The study raised
the po..ibility that the remedy selected in the December, ~984
ROD would be of liaite4 effectivene.. without the in.tallation of .
a barrier vhich vould limit upward movement of contamination 'from
the underlying bedrock.
As a re.u1~ of the partie. proposal based on the CFS, EPA
negotiated. Partial consent Decree with ciba-Geiqy corporation,
SmithKline B8ckaan, wyeth Laboratorie., and Es.ex Group to
implement an innovative technology, vacuum extraction, that would
be more effeetive than excavation in removing the contamination
from the .oil. and underlying bedrock at the on-site area. In
March, 1988 EPA revised the soil excavation ROD of December, 1984
to replace the excavation remedy with the innovative vacuum
extraction reaedy. The partial Consent Decree was .igned and
enter.d June 20, 1988. The vacuum Extraction process va. put in
-------
full operation in November, 1988 and to date has removed
approximately 100,000 pounds of organics from the contaminated
soils on-site.
On August 23, 1988, ERM submitted, on behalf of Ciba-Geigy, the
draft Off-Site Operable Unit FS to EPA. This report recommended
a no-action alternative for the Seep Area, Railroad Area,
Hillside Area, and Floodplain/Wetlands areas. The second ROD for
the site signed on September 29, 1988 and based upon the Off-
Site Operable Unit RI/FS Report, selected the no-action
alternative for those areas of this second operable unit.
With regard to the deep aquifer, the Off-Site Operable Unit FS
primarily focused on the recovery and treatment of contaminated
groundvater south of the Schuylkill River. A recovery veil
network was designed by S. S. Papadopulos and Associates, Inc.
(SSPA, 1988) to intercept contaminated groundvater along the
south bank of the river. Many treatment alternatives vere
examined by the Off-site Operable Unit FS a* to their
applicability for treatment of the contaminated ground vater.
Ground vater recovery from a line of veils along the south shore
of the River with treatment via steam stripping followed by
liquid-phase carbon, if required as a polishing step, was
selected as the ground vater alternative in the second ROD for
the Tyson's site.
At the conclusion of the Off-Site Operable Unit Feasibility Study
(FS), it was determined that additional investigation of the
extent of site-related compound migration in the deep aquifer
north of the south bank of the Schuylkill River vas required
before remediation of the ground vater affected by the Tyson's
site could be fully addressed. Specifically, the objectives of
the additional vork described in the Third Addendum to the Off-
site Operable Unit Remedial Investigation (RI) Work Plan vere to:
o Complete, to the extent possible, the delineation of the
extent of dissolved phase site-related compound migration in
ground; \
o Establish boundaries on the distribution of DNAPLS; and
o Obtain sufficient information relative to the mechanisms
controlling the movement of ground vater south, beneath, and
north of the Schuylkill River so that alternatives for
remediation of site-related compounds in the deep aquifer
could be properly evaluated.
The Third Addendum Investigation included the sequential
installation of additional monitoring veils on Barbados* Island
and on the north side of the River, along vith extensive
hydrogeologic testing and ground vater sampling. As a result of
-------
8
these activities, sufficient information was obtained on the
mechanisms of ground water flow and extent of site-related
compounds to permit completion of a focused Feasibility Study for
that portion of the deep aquifer that extended to the north bank
of the River. The off-site operable unit third addendum RI and
FS reports were submitted to EPA in May and June, 1990
respectively. Based on these reports it was determined that
addi tional information.. on the relationship of the ground water in
the deep aquifer no~h of the river to the river should be
obtained. .
Community Relations
The Third Addendum focused RIfFS, Proposed Plan and background
documentation for the Tyson's site were made available to the
public on July 24, 1990 in the local information and
administrative record repository at the Upper Merion Township.
Municipal Library located in the Upper Merion Township Municipal
Building, Upper Merion Township, Pennsylvania. Notice of the
availability of these documents, of a public comment period, and
a public meeting was published in both the Philadelchia Dailv
~ and the Norristown Times Herald on July 24, 1990. A public
comment period was held from July 24, 1990 through September 23,
1990. Additionally, a public meeting was held at 7:00 p.m. on
August 9, 1990, at the Upper Merion Township Municipal Building.
At this meeting, representatives from EPA and PADER answered
questions about the Tyson's site and the remedial alternative
under consideration. Written comments received during the public
comment period are addressed in the Responsiveness Summary which
is an attachment to this Record of Decision. The above actions
satisfy the requirements of Sections 113(k) (2) (i-v) and 117 of
CERCLA, 42 U.S.C. S S 9613(k) (2) (i-iv) and 9617.
A
ScoDe and Role ot ODerable Units
Between January 1983 and Auqust 1985, EPA conducted a. series of
investigati~ns, primarily in what had been referred to as the on-
site area (operable unit 1). The on-site area encompasses the
former lagoons (see figure 1). In March, 1988, EPA issued a
revised Record of Decision (ROD) for the on-site area (operable
unit '1) which selected a remedy proposed by Ciba-Geigy .
Corporation, namely soi1 vacuum extraction. This remedy, which
is perforainq an in-place cleanup of contaminated soils was
commenced at the site in November, 1988.
The second operable unit at the Site consist of contaminated
groundwater in the bedrock aquifer up to the south bank of the
Schuylkill River. This contaminated groundwater was di8charging
to the River. In September, 1988 EPA issued a second ROD to
address treatment of contaminated groundwater discharging to the
Schuylkill River along the south bank. This second ROD which was
-------
9
selected steam-stripping of the contaminated groundvater, as
commenced at the Site in March, 1990.
The current ROD for, Operable Unit 3, addresses further
remediation of the contaminated groundvater which has migrated
beneath, and as far as, the north bank of the Schuylkill River.
This contaminated groundvater is one of the primary concerns
posed by the site. Additional investigations vill be conducted
on the north side of the River as part of the alternative
selected for this opefabJLe unit. Based on the result of those
investigations, a fourth operable unit may be identified and
further remediation of the groundvater may be warranted.
Summary of Site Characteristics
Previous Groundwater Investigations
Conclusions from the groundvater investigations from the original
Off-site RI and first and second addenda (except for wells north
of the River) indicate that the deep bedrock aquifer betveen the
former lagoons and the Schuylkill River is contaminated vith a
DNAPL and a dissolved phase derived from the ONAPL. The DNAPL,
vhich is composed primarily of 1,2,3, trichloropropane, xylenes,
ethylbenzene and toluene most probably entered the bedrock system
through direct infiltration from the former lagoons, which were
situated directly on or in the highly weathered and fractured
bedrock. Once in the bedrock, the ONAPL flowed along the
weathered bedding planes and fracture zones in the Lower Stockton
Formation and coated and penetrated the walls of the fractures
and bedding planes. The ONAPL has migrated through the deep
aquifer as far as the south bank of the Schuylkill River to
depths as great as 140 feet. The presence of residual DNAPL will
continue to generate dissolved-phase contamination in the deep
aquifer and is the present source of ground water contamination
to the deep aquifer. The dissolved-phase contaimination consist
of dissolved organic constituts such as trichlopropane, toluene,
xylenes and ethylbenzene.
The groundwater flow direction in the deep aquifer is north
toward the river. An upward flow gradient exist in the deep
aquifer underlying the floodplain and indicates that both the
ground water and dissolved phase contamination is discharging to
the River within the regional ground water flow system.
Based upon the above conclusions, it was determined in the off-
site FS and subsequently included in the September 1988 ROD that
ground water recovery and treatment was necessary to address
contaminated ground water discharging to the Schuylkill River.
-------
10
Bedrock Geology
Based on the Third Addendum RI report, the bedrock underlying the
area being investigated has been arbitrarily subdivided into
three heterogeneous lithologic units as shown in Figure 3. A
description of each of these units is provided below. The three
units are, from deepest to .shallowest: a coarse green arkosic
sandstone; a purple arkosic sandstone; and a red siltstone and
fine sandstone.
Green Arkosic Sandstone
The lower, or deepest encountered, lithologic unit consists of
medium coarse and very coarse-grained green arkosic sandstone.
This unit will be arbitrarily called the lower unit of the Lower
Arkosic Member of Stockton Formation. This unit has an average
feldspar content greater than 25 percent. The feldspars vary in
color from cream to orange, especially in the upper part of this
unit. Lithic fragments observed in this unit include
amphibolite, talc, serpentinite, schist, and shale. This unit was
observed to be at least 330 feet thick at Deep Bedrock Well 1
(DB-1) on the north side of the river. In DB-2 this unit was
observed to have a thickness of about 178 feet. This unit has
also been encountered in wells on the south side of the
Schuylkill River where minimum thicknesses of about 200 feet were
observed. The overall color of this unit is pale greenish grey,
bright green, and dark green. It contains interbeds of shale and
sandstone, sometimes 10 to 30 feet thick, that do not appear to
be continuous across the area. The shale is usually red to
redbrown in color. Occasional dark green shales were also
observed. Rocks similar in description to this unit appear to be
fairly extensive laterally and have been encountered not only in
DB-1 and DB-2 but also in MW-l (the site background well on the
south side of the river) and Cored Well (CW-4) , CW-5, MW-15S, and
MW-15D on the north side of the river.
The strata of this unit are probably highly susceptible to
chemical weathering due to the instability of the feldspar
grains. In Horristown, an example of this weathering was
observed where a stone wall built upon an escarpment of this unit
has been undercut due to weathering. CW-5, located on Barbados
Island, was difficult to install due to the highly weathered
nature of this unit. This unit is referred to in the RI report
as the green arkosic sandstone.
Purple Arkosic Sandstone
The unit overlying the green arksic sandstone is arbitrarily
called the upper unit of the Lower Arkosic Member of the Stockton
Formation and consists of arkosic, medium to coarse grained and
-------
Figure 3
Stratigraphic Column
Tyson's Site
Red Sittstone
and
Fine Sandstone
Purpto Arttosic Sandstone
• • •••••;
Green Aitosic Sandstone
200 n.
MMnum
130 ft. ±
330 n.
Minimum
No Scale
-------
12
very coarse-grained sandstone and arkosic conqlomerate with a few
minor siltstone. This unit decreases in qrain size upward.
There is considerable variability in qrain size within this unit,
but qeneralizations can be described. Coarse qrain sizes occur
in this unit, includinq well rounded quartz pebbles near the
base, lithic fraqments, and red shale fraqments. Rip-up clasts
of red shale have been seen in conqlomerates with the clasts
within beddinq suqqestive of imbrication. True beddinq planes
are difficult to de~erm~ne,_and the unit occasionally contains
dark lamellae sugqestive of cross bedding. Cross beddinq with
lamellae is not visible in the underlyinq qreen arkosic
sandstone. Colors of this unit ranqe from dark qrey, dark
purple, pink, and reddish-brown, often with a distinctive salt-
and-pepper appearance due to the presence of feldspar. Usually
the individuai grains are quite well cemented as observed in hand
specimens. Drill rates were noticeably less in this unit in
comparison to the finer grained overlying unit.
Topographically, the unit appears to be a ridqe-former in
comparison with the less resistant qreen arkosic sandstone. The
thickness of this unit is estimated to be at least 100 feet and
perhaps as much as 150 feet within the area of investiqation.
This unit is referred to in the RI report as the purple arkosic
sandstone due to its purplish to qrayish-purple ~ints,
particularly towards the bottom of the unit.
Red Siltstone and Sandstone
Rocks at the site stratigraphically above the two units of the
Lower Arkosic Member of the Stockton Formation described above
have been identified as the Middle Arkosic Member of theStockton
Formation. Rocks of the Middle Arkosic Member has been mapped by
the Pennsylvania TOPographic and Geologic Survey as occurrinq
partially on the western end of Bardbadoes Island and also
extensiv.ly ~n the north side of the Schuylkill River startinq at
a point jus~ west of Haws Avenue and continuing westward.
Rocks in this upper unit were observed to be generally finer
qrained than those in the two underlying units and had a much-
qreater proportion of red siltstone and shale. The general
arkosic character of rocks, as observed in the Lower Arkosic
Member, tend. to disappear and the proportion of mica increases
with decreasing depth. Grains are qenerally loosely to
moderately cemented. Many shale-units appear to have white
discolored stringers and irregularly shaped spherical masses.
These may be the remains of animal burrows in what were at one
time muds at a shallow depth. Similar burrows occur less
frequently in stratigraphically lower rocks.
Individual rock layers in all three of the units appear to have a
hiqh deqree of variability, especially in the Middle Arkosic
Member.This is in keepinq with the probable alluvial fan
I
I-
I
I
-------
13
(fluvial) depositional environment of many of these rocks. Due
to this variability, units with thicknesses of 100 feet or more
have been chosen for correlation.
Bedrock Hvdroqeoloqry
The bedrock aquifer at the Tyson's site is the Lower Member of
the Stockton Formation. Recharge to the bedrock aquifer occurs
in the areas south of the site where the Lower member is exposed
or close to the surface. Both primary and secondary permeability
are apparent in all three zones monitored in the bedrock aquifer.
Primary permeability is contributed from the intergranular space
between grains of material comprising the matrix of the bedrock.
Primary permeability is variable depending on the competency of
the matrix between the coarser grains. The matrix experiences
variable degree of weathering observed at the site outcrops and
in cores obtained during previous investigations. Highly
weathered portions of the aquifer provide greater primary
permeability due to the decomposition and removal of the matrix.
In less weathered intervals, the argillaceous matrix fills the
space between coarse grained material, thus reducing
permeability.
Secondary permeability is contributed by discontinuities such as
joints, fractures, faults, and weathered bedding planes. The
occurrence of significant zones of enhanced secondary
permeability ia represented by fracture traces. The fracture
traces are indicative of vertical planes of fracture
concentration. These planes act as conduits for groundwater flow
and represent preferred paths for the migration of contaminants
in groundwater.
Groundwater and Schuylkill River water levels have been monitored
at the site as part of a number of investigations. As part of
the Third Addendum RI, water level elevations have been measured
on a regular basis for the completed monitoring wells on
Barbadoes Island and the north side of the river. Using the
groundwater elevation data, an attempt was made to describe the
occurrence of groundwater in the deep aquifer in the vicinity of
the Tyson's site, both prior to and following the start up of the
Interim Ground Water Recovery System (November 1988) An attempt
was also mad* to describe the seasonal variations in water
levels, the relationship of groundwater levels in the deep
aquifer to the Schuylkill River, and the horizonal and vertical
components of groundwater flow.
The potentiometric surface maps shown in figures 4, 5 and 6
reflect groundwater conditions on October 13, 1989 in the
shallow, intermediate, and deep zones of the deep aquifer on the
south side of the River prior to the initiation of pumping at the
Interim Ground Water Recovery System. Within the shallow zone,
the potentiometric surface reflects the surface topography with a
-------
Figure 4
Shallow Potentiometric Surface
- October 13. 1988
•»• W«iMmLoCMnn
It 06 Stalv* B«*oc» W«« WM«I («v*l of R'vti
Pt*ionw<«> Wjim i«vai (m Feel above M^L)
-------
Figure 5
Intermediate Potentlometrlc Surface .
Tyson's Site - October 13, 1988
• *. n «••• confraMs to
.». C«*aMMI.in*(DmiMl.
« E«iri Ofound Wuw Eltvalnni
(Mind W«« FkM O«eci Waiei I eve) 01 Ri»ei
ftttomav Wai« I evel |m reel above MS>)
-------
Figure 6
Deep Potentiometric Surface
I'B Site - October 13. 1988
EqufeMMM Lkw (Ocnoln Lin*
Wei Wai*. Levtf or Riw
-------
17
gentle mounding in the center of the site and flow northward,
towards the River. For the potentiometric surfaces of the
intermediate and deep zones, the orientation of the ground water
mound is skewed somewhat to the east. These potentiometric
surfaces are consistent with those presented in the Off-Site
Operable Unit RI Report. Hydraulic gradients within this portion
of the deep bedrock range from 0.032 to 0.073 (dimensionless).
Potentiometric surface maps were not constructed for the deep
aquifer beneath and north of the Schuylkill River. The greatly
increased spacing between wells beneath and the variable well
completion depths prevent construction of anything but a grossly
interpretative potentiometric surface map.
Water levels in the shallow zones of wells installed on the
island (CW-4 and CW-5) and Well Nest 15 (WN-15) on the north side
of the River are nearly the same as the water levels in the
Schuylkill River, indicating that there is a relationship between
water levels in the shallow zone and the River. Water levels at
installations north of the River (CW-3, CW-7, and CW-8) are
nearly equal to or slightly higher (water level differences range
between 0 to 4.7 feet) than the River, indicating that the
potential is present for shallow ground water flow toward the
River at these wells. The lack of monitoring points north of CW-
3, CW-7 and CW-8 prevents the development of a potentiometric
surface map extending north of the north bank of the Schuylkill
River.
Figures 7 and 8 present vertical gradients at selected locations
on April 17, 1990 (Interim Ground Water Recovery System
operating). Upward vertical gradients between shallow, deep, and
extra deep veils occur at well nests 3, 4, 5, 6, 8, 9, 10, and
11. These well nests are generally located in the central
portion of the site south of the River. Upward vertical
gradients in these well nests range from 0.09 to 0.21
(dimensionless). This upward vertical gradient adjacent to the
River would be expected as the River represents a regional ground
water discharge point.
An analysis of upward groundwater flow along the south bank of
the River was completed as part of the Off-Site Operable Unit FS.
Earlier, It had been predicted that the 1,2,3 trichloroprapane
mass discharge to the river should result in a 1,2,3-
trichloropropane concentration in the River of about 40 ug/1. In
this calculation, it was assumed that all horizonal groundwater
flow from south of the River discharged to the River. Historical
data showed that 1,2,3-trichloropropane concentrations in the
River were in the range of 0.5 to 2.0 ug/1, considerably less
than that predicted.
-------
Figure 7
North-South Trending Hydrogeologic Cross Section
I'B Site - April 2, 1990
-Sdw»M Mlvw
CW-J-.
T
J-4
I
rCW-4
• ZD
115
R«*raM
Out
«-D 77 •
10-1 flitl
10-XD 7161
C'OM Siclion OiKnlalion li N8*C
EMlanallon
CW i Cond «••» w»l) Muti> B.«oc» «¥••
CW • £.I.action W«ll
MW , Bl Monlloc.nq Writ
V»H .- Rl Manrlonng Will N«|l
-W«IN«IUic«ton
Jzse
23 6B
V
Ground WiM> Elevainn
(IMI Aov« MSL)
-------
Figure 8
East-West Trending Hydrogeologic Cross Section
Tyson s Site - April 17, 1990
EW
«•» . m M^IO.*,,--„.,
W* • m MMrilwIn, M.( N...
-------
20
To account for the disparity between the predicted and observed
1,2,3-trichloropropane concentration in the River, a new analysis
was completed considerinq spatial variations in permeability
across the site. This analysis is based on observed hydraulic
qradients near the River and an assumed 10:1 anisotropy of
permeability across geologic bedding (alonq bedding permeability
is ten times greater than permeability across bedding). The mass
discharge calculate4 usinq this new analysis resulted in
predicted concentrations of 1,2,3-trichloropropane in the River
of 0.7 ug/1 to 3 ug/1." These concentrations compared well with
the actual observed concentrations in the River. The results of
this analysis suggested that anisotropy along beddinq is very
important to consider when evaluating groundwater flow velocities
in the stockton Formation. Also, vertically upward components of
ground water flow in the River occur only alonq a limited area
(i.e., not all qround water discharges to the River, as was
initially anticipated). Downward vertical gradients exist
between the shallow and intermediate wells at well nests 7 and 12
on the south side of the River.
The ground water flow directions at the site have been determined
with a high degree of confidence south of the Schuylkill River.
This is a result of the extensive ground water investigations
conducted on this portion of the deep aquifer. Ground water flow
in the deep aquifer north of the south bank of the River is
described as follows.
Vertical hydraulic gradients beneath Barbados Island are very low
if present at all. Horizontal hydraulic gradients and directions
of ground water flow in the shallow bedrock aquifer beneath of
the river are low and poorly defined. Both strong upward
hydraulic gradients CW-7 and cw-a and strong downward hydraulic
gradients (CW-3) occur between shallow and deep intervals
monitored alonq the north bank of the River. Aquifer
transmissivitles determinations made durinq the installation of
CW-7 and cw~a indicate that aquifer transmissivities in the
bedrock aquifer on the north bank of the river are likely to be
similar to those seen previous testing south of the River.
Horizontal hydraulic qradients and directions of qround water
flow on the north side of the River could not be determined.
Shallow qround water may discharge toward or into the Schuylkill
River. Due to the presence of both strong upward and downward
vertical hydraulic qradient at wells north of the river, deeper
components of ground water flow are not well defined. A strong
upward qradient at depth suqgests that a portion of the qround
water flow is towards the River. Downward hydraulic qradients at
CW-3 suqgest that this feature may be actinq as a drain with
ground water possibly flowinq to the north. The potential for
ground water pumping, geologic structures i.e., faulting), and
hydraulic properties of the aquifer to affect ground water flow
near this well are not understood.
-------
21
Nature and Extent of Contamination
Deep Aquifer Ground Water Quality
The vertical distribution of site-related compounds was assessed
by installing the monitoring veils with sampling intervals that
roughly correspond to one another from near the former lagoons to
the north side of the Stfhuylkill River. In general, the
monitoring veils near the former lagoons had sampling intervals
(open hole completions) in the upper 50 feet, 75 to 150 feet, and
150 to 200 feet. These sampling interval depths vere then
projected so that veils could be installed north of the River
vith open intervals that correspond to those installed south of
the River. Eeep Bedrock Well l(DB-l) is an example of a downdip
veil installed on the north side of the River that corresponds to
a depth at vhich DNAPL vas found in veil nest 8 on the south side
of the River. Some of the shallower sampling intervals in the
Waterloo Multi-Level Piezometers (WMLPs) installed on the island
and north of the River do not correspond in depth to intervals
monitored on the south side of the River but do, hovever, provide
valuable information on the distribution of site-related
compounds and ground vater hydraulics.
The horizontal distribution of site-related compounds vas
determined by successive installations of additional monitoring
veils to the east and vest of existing veils in vhich site-
related compounds had been found. These lateral locations,
either multiple veils or WMLPs, vere used to further assess the
vertical distribution at depth.
Over 70 groundvater samples have been collected as part of the
Third Addendum Investigation. Most of these samples vere
analyzed for Toxic Compound List (TCL) volatile organic
compounds, TCL semi-volatile organic compounds, TCL inorganic
compounds, 1,2,3-trichloropropane, and the classic parameters of
total organic carbon, total suspended solids, hardness,
alkalinity, and total iron.
As per the Off-Site Operable Unit RI Report, the organic fraction
found in the highest concentration throughout the Third Addendum
Investigation vere the volatile organics. Of the volatile
organic*, 1,2,3-trichloropropane vas the organic compound found
most frequently and at the highest concentrations. Other
volatile organic compounds commonly detected at elevated
concentrations include xylenes, toluene, and ethylbenzene. These
are also the major compounds that constitute the site's DNAPL.
Because 1,2,3-trichloropropane vas the most commonly detected
compound in the ground vater samples and is a major component of
the DNAPL, it has served as the tracer compound for the Tyson's
-------
22
site. Table 1 presents a summary of analytical results for
1,2,3-trichloropropane and other commonly detected volatile
organic compounds in RI monitoring wells.
As described in the Off-Site Operable Unit RI Report, physical
evidence of DNAPL is not always easy to obtain, even if a ONAPL
is present near the yell or in sufficient concentration to impact
the water quality at a -well location. The rule of thumb is that
if dissolved-phase organic concentrations approach 10 percent of
the equilibrium solubility concentration for a particular organic
compound, then it is quite possible that a DNAPL is present. The
major component of the ONAPL, 1,2,3-trichloropropane, has a
solubility of 1,900 mg/1; therefore, dissolved-phase 1,2,3-
trichloropropane concentrations of about 190 mg/1 are considered
to be indicative of a ONAPL presence.
The bedrock aquifer is subdivided into shallow intermediate, and
deep zones, although, these are not to be considered as
distinguishable, individual flow zones. The following is a
summary of the ground water quality in each of these zones:
Shallow Zone
An isoconcentration map of the distribution of site-related
compounds in the shallow zone is presented in Figure 9. In the
upper 50 feet of bedrock, the center of the plume has migrated
from the former lagoons downdip (northwesterly) and at a 30
degree angle to strike (north) from the former lagoons.
Concentrations of volatile organic compounds in these wells (3-
S, 5-S, 6-S, and 11-S) are in the hundreds of mg/1, indicative of
a DNAPL influence on ground water quality. The lateral
boundaries (east and vest) of the plume in the shallow bedrock
south of the River are well defined by the results from samples
collected annually at well nests 9 and 12 and other samples
collected at extraction well 6 (EW-6) where site-related
compounds have not been detected or found at very low
concentrations (less than 5ug/l 1,2,3-trichloropropane). .
CW-4 is located on Barbadoes Island directly across from wells on
the south bank of the River where the highest concentrations of
site-related compounds have been detected (in well nests 8, 10,
and 11). At CW-4, site-related compounds were found at the 37-
to 58-foot interval. A second well installation (CH-5) on the
island to the east of CW-4 has had no detections of site-related
compounds, thus providing an eastern limit to the plume geometry
on the island for the shallow groundwater zone.
North of the river in the shallow zone, site-related compounds
have been detected at CW-i, cw-2, CW-3, and CW-8, due north of
CW-4 where the highest levels of site-related compounds were
found. The concentrations of 1,2,3-trichloropropane in CW-1 in
the shallow zone, as defined by intervals 4 and 3 (87 to 105 feet
-------
Table 1
-------
[-
Table 1 (Cont'd)
..... .... or J.- -
~ , .......
/ ~....
.... ...... 'P . ...A..
- a
CW.I . .,... 4 .. ....
. I". I. 4 10 ....
I ns..., 4 ID ..
I 4 ... 118 . .. ...... .. , II) t.'"
. IDal., . .. ....... .. Ie ....
J ........ . Ie ....... ID .. .....
..
~ CW., .. lID 10 .....
.. 'AII .. 10 '..2
CW-4 ''''''.14 ..- Ie .. .....
..... ..'''02 ."'7".18 Ie 11.'
...... I.""'. II '....02. ..... 218
CW.. ..
..
CW.' ID '..7
ID ID .....
ID .. ..81'
ID ''''1
.. lID .....
. ... ....
10 .....
lID
... . 18111 ...... ".
- . - .........
I -
.... .... ..... II ... 4d"'"
......
-------
Figure 9
Isoconcentratlon Map of Total
Volatile Organic Compounds in the
ou-11 —. Bedrock Zone
Norristow?i
-------
26
and 132 to 155 feet), ranges from 0.0031 mg/l to 0.43 mg/l.
1,2,3-trichloropropane was not detected in the shallow zones of
CW-2, CW-3, and CW-8. only low concentrations of toluene were
detected in the shallow intervals of these wells. Therefore, the
absence of detectable concentrations of site-related compounds in
the shallow intervals .at CW-2, CW-3, CW-7, CW-8 and well 15-5
allows the lateral boUndaries of the plume east and west along
the north bank of ttie river- to be approximated
Intermediate Zone
Fiqure 10 is an isoconcentration map of total volatile organics
in the intermediate zone. In general, the highest concentrations
of site-related compounds were detected in intervals completed in
the intermediate zone. South of the river at depths of 100 to
150 feet, the highest concentrations of site-related compounds
are present both in a downdip direction at a 30 degree angle to
strike. Concentrations of volatile organics in wells in this
central portion remain high, in the hundreds of mg/1, with the
observation of measurable quantities of ONAPLs at wells 81 and
31. Again, the lateral extent of the plume south of the River is
noted by the absence or near absence of detectable concentrations
of site-related compounds at well nests 9 and 12.
At CW-4, concentrations of 1,2,3-trichloropropane in the
intermediate intervals (intervals 2 and 3, 65 to 78 feet and 87
to 121 feet, re8pectively) range from 30 to 250 ppm. The
intermediate intervals at CW-5 to the east of CW-4 remain free of
site-related compounds. North of the River at CW-1, site-related
compounds were found at the intermediate intervals (3 and 2) with
concentrations higher than those found in the shallower
intervals. The highest 1,2,3-trichloropropane was 2.9 mg/1 in
interval 3. Again there were no detected concentrations of site-
related Qompound8 in the wells along the ~EOO right-of-way to the
east or west of CW-1.
DeeD Zone
Figure 11 i. an isoconcentration map of the total volatile
organic concentrations in the deep zone. In the deep zone south
of the river, the central portion of the contaminant plume has
shifted to the west and is centered around well nest 10 (10-0 and
10-XO). At this location, concentrations of 1,2,3-
trichloropropane ranged from 20 mg/1 to 120 mg/1. To the east at
well nests 8 and 11, ground water quality in these deeper
intervals is much improved (15.1 mg/1 and 35.2 mg/1 total
volatiles, respectively compared to overlying zones at these
locations. This water quality trend was confirmed by the
resampling of these wells in February and March 1990. Again,
with regard to the lateral boundaries of the plume, the low
levels of detected site-related compounds in well nests 9 and 12
-------
Figure 10
Isoconcentration Hap of Total Volatile
Organic Compounds in the Intermediate
•,_1 « » "
Norristown
x \/
PA
x
Woter Co /
OOOJ»,
WN - 15
-------
Figure 11
Isoconcentration Hap of Total Volatile
Organic Compounds In the Deep
Bedtoek Zone
Norristown
-------
29
and EW-6 confirm the lateral extent of contamination in the
deeper zone.
The highest concentrations of detected 1,2,3-trichloropropane
were found at CW-4 on Barbadoes Island at concentrations as high
at 1,200 mg/l. No site-related compounds were detected at CW-5
to the east of CW-4..
Similar to CW-4, the wells on the north side of the Schuylkill
River where site-related compounds were detected also showed a
consistent increase in concentration with depth from the shallow
to intermediate to deep bedrock zones. The highest concentration
of 1,2,3-trichloropropane (6 mg/1) was found at CW-1 in the 223-
to 250-foot interval. Significantly lower concentrations (0.006
mg/1) were detected at CW-8.
To determine the extent of site-related compound migration from
the former lagoons to the north side of the Schuylkill River at
depth, DB-2 was installed with an open interval of 350 to 450
feet. Concentrations of 1,2,3-trichloropropane in a sample
obtained from this well are much lower (0.12 mg/1) than the
1,2,3-trichloropropane concentrations detected in the deeper
intervals of the adjacent CW-1.
DNAPL
Figure 12 provides a conceptual schematic of the DNAPL movement
from the former lagoons in the deep aquifer. It is thought that
the DNAPL moved downward through joints along weathered bedding
planes in a downdip direction. In this manner, joints and
bedding planes become coated with ONAPL. In the past,
observations of ONAPL have been noted atop one of the secondary
porosity preferential paths, a thin, discontinuous shale unit
seen in the center of the site at well nests 3,6,11 and 8. This
unit, however, cannot be continuously mapped from the former
lagoons to the north side of the river. Based upon the physical
observation of DNAPLs and the "10 percent of solubility rule" of
thumb, the extent of the ONAPL plume has been characterized as
extending from beneath the former lagoons to a depth of
approxiaately 135 feet south of the Schuylkill River to at least
a depth of 200 feet beneath Barbados Island. There is no
indication from the data available that there is a DNAPL present
beneath the north bank of the Schuylkill River.
Community Well Investigation
A sample submitted for TCL volatiles and 1,2,3-trichloropropane
analysis was collected from a well at Morabito's Bakery at 757
Kohn Street in Norristown, on January 11, 1990. Nona of the TCL
volatile organic compounds were detected in this sample. Only
two other ground water receptors were identified on the north
side of the River during the Third Addendum Investigation. One
-------
Figure 12
Conceptual Schematic
off DNAPL Movement-
Cross Sectional View
Tyson's Site
« ONAPl ra ON»Pt t
IOMIW togoora «nl n nta JMd bf «l «MMd
0WM canc*MM«i« CW 4
SuifxcMO *•• ol ONAPI and ONAF1
imdMl in «n cn>«i McMiui »•«•
Ik* ln«n kiMtai How •• poiubto
-------
31
well, located at 49 Buttonwood Street, would not allow a sample
to be collected. This well is reportedly not used as a drinking
water supply. Another well located at the Norristown State
Hospital was sampled and the results indicate that site-related
compounds have not impacted the water quality used at the
hospital.
Summary of Site Risks
*
The risk assessment performed on the deep aquifer at the Tyson's
site during the third addendum RI/FS primarily reiterates
previous risk assessment conclusions on the deep aquifer found in
the off-site RI/FS report in 1987. Ground water and surface
water were identified as the media at the site to which human
exposure populations may be exposed.
In November 1987 a document entitled "Calculation of Cleanup
Levels for the Former Lagoon Area - Tyson's Site" was submitted
to EPA. This document was prepared in concert with USEPA for the
purpose of establishing soil cleanup levels for remediation by
vacuum extraction of the former lagoon area. To calculate
appropriate soil cleanup levels, health-based acceptable intake
levels for each compound in the former lagoons were first
identified. The health-based acceptable intake levels included
large safety factors or highly conservative assumptions and thus,
represented fully protective levels. The soil levels necessary
to achieve these acceptable intake levels were then calculated
using hypothetical exposure scenarios. The exposure scenaros
were jointly selected by USEPA and ERM and were intended to
result in soil levels that would be fully protective of human
health. One of these scenarios was hypothetical potable use well
at the boundary of the former lagoon area that assumed 1) any
residual soil contamination (i.e., remaining after vacuum
extraction) was released into the ground water from which the
well draws, and 2) a lifetime of exposure to the water from the
well for all uses.
\
Once the calculations were done for each of the exposure
scenarios, the scenario producing the most stringent cleanup
requirement was selected as the soil cleanup level. In almost
every instance, the most stringent level was the scenario which
assumed that soil contamination gives rise to ground water
contamination and that a residential well drawing only this
contaminated ground water was used for all household purposes for
a lifetime.
The health-based acceptable intake level for compounds detected
in the former lagoons for the hypothetical well scenario have
been the only calculations ever conducted for acceptable levels
of Tyson's site compounds in ground water. Table 2 provides the
acceptable chronic water exposure levels provided in the above
mentioned report.
-------
32
The complete text of the document "Calculation of Cleanup Levels
or former Lagoon Area - Tyson's Site" can be found attached to
the Memorandum of Understanding dated June 16, 1987 and the
Administrative Order of Consent for the vacuum extraction
technology dated February 17, 1988. Table 2 provides the
acceptable chronic water exposure levels provided in this report.
. -
The calculation of 1,2,3-trichloropropane's potency factor used
to derive the acceptable 1,2,3-trichloropropane chronic exposure
level shown in Table 1-1 was detailed in Appendix G of the Off-
Site Operable Unit Endangerment Assessment, (ERN, 1987). Since
toxicological information was not available for 1,2,3-
trichloropropane in 1987, and acceptable levels were not
available from USEPA, an oral and inhalation potency factor was
derived for this compound. The potency factors were based on
only those chloroalkanes and bromochloropropanes which were
classified as Group B and established carcinogenic potency
factors. The potency factor for 1,2,3-trichloropropane was
calculated to be 1.X10.' (mg/kg/day). This interim potency
factor was calculated specifically for the Tyson's site and was
to be used until new toxicological information becomes available.
To date, no new toxicology information for l,2,3-trichloropropane
has been released from the USEPA or National Toxicology Program.
This is important since l,2,3-trichloropropane is the most.
significant indicator compound for the site and is the compound
monitored in the Schuylkill River regarding the effectiveness of
the Interim Ground Water Recovery System.
On July 29, 1987 ERN submitted to USEPA on behalf of CIBA-GEIGY
the Off-Site Operable Unit RI Report which included as volume 5
the endangerment assessment for the off-site operable units
including the ground water in the deep aquifer to the south bank
of the Schuylkill River. This EA was focused on the river as
being th~only receptor of site-related compounds from the
Tyson's"site, specifically at the Pennsylvania American Water
Company crib intake in the south channel of the Schuylkill River
approximately 2,000 feet down river from the Tyson's site.. It
was determined that the most important compound for the site was
1,2,3-tr1chloropropane. The pathway of concern was from the
former 18900ns via the bedrock aquifer to the Schuylkill River.
At the ~18e that this report was prepared, it was considered that
all ground water in the bedrock aquifer containing site-related
compounds discharged to the Schuylkill River. The exposure
scenario or receptors of site-related compounds at the crib
intake included drinking and showering by humans. The EA for the
off-site operable units used as its basis for water quality the
limited river water and sediments data obtained during the Off-
Site Operable Unit RI and information made available from the
Philadelphia Water Company for its two downriver intakes
(approximately 12 to 13 miles down river from the site).
-------
Table 2
Tyson'* Sit*
Acceptable levels in Ground Water
CCMPCUC
ANILINE
ANTHRACENE
BENZENE
BENZOIC ACIO
BIS<2-ETHYLHEXYL)PHTHALATE
2-BUTANONE
CHLOROBENZENE
2-CHLORONAPHTHALENE
2-CHLOROPHENa
CHRYSENE
CYCLOHEPTATRIENE
CYCLOHEXANCNE
DI-N-BUTYL PHTHALATE
DI-OCTYL PHTHALATE
DCHLOROBENZENES
2.4-OIMETHYLPHENOL
N.N-DIMETHYL-1 ,3-PROPANEDIAMINE
POPPVr^F
ETHYLBENZENE
1 -ETHYL-2-METHYLBENZENE
FUJORANTHENE
HEXADECANE
HEXADECANOIC ACID
• •^•r^r^B^^B^P^^V v^p^^pr ^^%^'ejp*
METHYLENE CHLORIDE
2-METHYLNAPHTHALENE
2-METHYLPHENOU444ETHYL PHENOL
4-METHYL-2-PENTANONE
N-NITROSOOIPHENYLAMME
NAPHTHALENE
NJ 1 rkjbermEfiE
1 ,1 -OXYBISK2-ETHOXYETHANE)
PHENANTHRENE
PHENOL
PYRBC
TBBfTPA^M OQPCTUJC1UC
TETRAMETHYLUREA
TOLUENE
1 Z4-TRICHLOR06ENZENE
1 ,3.5-TRlCHLOROBENZENE
TRCHLOROETHENE
1 2>TRICHLOROPROPANE
1 ,2.4-TRIMETHYLBENZENE
TRIOECANE
UNOECANE
0-XYLENE
•* 1,2 Dichlordbenzene 3.1E+00
* 1,3 Dichlordbenzene 3.1E+00
* 1,4 Dichlordbenzene 1.5E-03
Chronic water
expsoure, mg/L
oral
6.1E-03
7.00E + 00
2.20E - 04
7.00E - 01
2.5E-03
1.80E + 00
6.00E • 02
1.10E - 01
1.00E - 01
1.50E - 06
2.00E - 02
2.30E + 01
3.50E * 00
6.30E • 01
* * * *
2.80E - 01
6.50E • 01
390E + 00
W* ~ W i
200E - 02
•Wwi We»
1.60E • 03
5.30E - 01
1.80E + 00
1.80E + 00
7.1 OE - 03
1.4E-01
1.80E - 02
8.50E - 01
2.50E • 01
1 . 4E+00
3.8E-05
23QC . 04
• WWb W^
7.80E • 01
2.00E 4- 00
2.30E • 01
2.30E • 01
1.10E • 03
3.50E • 04
3.00E * 00
4.10E • 01
1.80E • 01
1.20E - 01
-------
34
During the Off-Site Operable Unit RI and subsequent FS, the
approach was to focus on remediation at the receptor and not
aquifer restoration. This was done for two reasons:
*
There are no wells extracting ground water between the
site (no known or identified receptors) and the south
bank of the Schuylkill River, and
*
. -
The presence of a large volume of DNAPL at depth in the
fractured bedrock aquifer made it impossible to
reasonably consider any alternative for aquifer
restoration with means currently available. During the
five year review required under SARA, this will need to
be revisited. -
Considering the above, all subsequent analyses of risks
posed by ground water in the deep aquifer focused on the
ground water which discharged to the Schuylkill River and
the impacts of the discharged ground water on river water
quality. The Interim Ground Water Recovery System waa
designed and installed to ~aintain an acceptable level of
1,2,3-trichloropropane at the crib intake.
Excosure Assessment
The indicator compounds, pathways, receptors, and exposure
scenarios, addressed in the third addendum Focused FS remain
identical to those previously assessed in the off-site RIfFS.
That is, dis801ved phase 1,2,3-trichloropropane the major
component of the DNAPL, entering the river via discharge from the
bedrock aquifer with the ultimate receptor being the users of
surface water taken from the river at the crib intake.
The third addendum Focused FS is solely concerned with ground
water ~n 'the deep aquifer to the north bank of the Schuylkill
River. The receptor of this contamination is the Schuylkill
River. Although the presence of site-related compounds in
monitoring well. on the north side of the river has been
documented and will need to be addressed further, it p'resents an
excess human cancer risks presently estimated at 2X10.z. This
level of 2xlO.z means that no more than two out of one hundred
people exposed for their entire lifetimes are at risk of
developing cancer from ingesting this contaminated well water.
One ground water receptor, the Norristown State Hospital, has
been identified on the north side of the River. Sampling results
from this well indicate that site-related compounds have not
impacted the water quality used at the hospital.
Toxicitv Assessment
The relationship between the extent of exposure to a contaminant
and the potential for adverse ef~ects was evaluated during the
-------
35
toxicity assessment process in the off-site RI/FS. Cancer
potency factors (CPFs) were identified for potential carcinogenic
contaminants, and reference doses (RFDs) (which are labelled
'AIC', 'AIS', or 'ADI') were identified for chemicals
exhibiting noncarcinogenic effects. CPFs and RFDs used for the
toxicity assessment are presented in Table 3.
Cancer potency facto~s (CPFs) have been developed by EPA's
Carcinogenic Assessment ~roup for estimating excess lifetime
cancer risks associated with exposure to potentially carcinogenic
chemicals. CPFs, which are expressed in units of (mg/kg-day)-',
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 that 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.
Reference doses (RfDs) have been developed by EPA for indicating
the potential for adverse health effects from exposure expressed
in units of mg/kg-day, are estimates of lifetime daily exposure
levels for humans, including sensitive individuals which are
believed not to cause adverse health effects. Estimated intakes
of chemicals from environmental media (e.g., the amount of a
chemical ingested from contaminated drinking water) 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.
'.
ComDarison to ADDlicable or Relevant and ADDroDriate Reauirements
CARARs}
Groundwater Contaminant-specific ARARs
For the purposes of the Third Addendum Focused FS, effluent
limit. after groundwater treatment were derived in the Off-Site
Operable Unit FS from those ARARs applicable to the River. When
more than one effluent limit was available for a given compound,
the most stringent of the limits was employed. These include the
discharge limits assigned by PADER, MCLGs, and surface water
criteria (Table 4). As shown on Table 4, there are many
compounds detected in the groundwater in the deep aquifer that do
not have effluent limits. For these compounds, risk-based
concentrations were derived in the Off-Site Operable Unit FS.
Since these concentrations are derived based on human
-------
•tmttnwiraNaMjrvcMreMpujeKxxi
E - eOUNHUMT MMC •fMMI HmofFICC OF HUD MMmE
MTCPba
IME-OI)
-------
Table A
Tyawi'a Site
(AMAH.)
'•!•!»••
WtfwiFM
FMiOn*
(2)
Chronic
•otara
l!i
I1-1'' ""• ••!•!»• (tot*!
|'»°W*»«P.«M^
IT'teMoto.Niww
;i3;2±^«^-
»*I*UI«*
'••*0.««a3
1.9201+03
•.OOE
I.OOE
1006
I.OOE •
»ooe -
7006 •
• OOE
2006*
• OOE -
I OOE*
- 09
- 01
- Ot
01
03
01
03
00
03
01
1 flOC
• -VM^K
2 OOE
•* f OOE
3606
• TOE
1406
•.OOE
7 OOE
1.43 E
3 006 -
:4M
- OB
-Ot
-04
-01
- 02
»00
• 09
04
«OI
09
4JOE
t.OOE
• TOE
I40E
• OOE
1436 <
270E-
-04
- 01
-04
•02
• 09
04
>OI
03
4006
1.S7E
1 416
3 20E
• 056 -
4 246 *
• 07E -
• 02
-02
02
03
O3
02
02
• 406
t IOE
t04E
• 756 , —
• 01
*00
* oo
t
«oa
t.OOE « 01
309E Ot
2 OOE » 00
1 IOE *Ot
• 05E 01
IflSE «00
22SE »00
t2«E
: 2366
« JMftC
3.^PC
(<^c
Jftt
2IOE
• IOE
5606 -.
01
- 01
- 01
* 00
« 00
• 02
- OI
2 376 * 00
1 306 - 01
330E 01
4.606 - 01
a.4«««i
!•« OfeMMytplMnoi
-MM4 upon • PAO6R
••T
-------
38
consumption, they are applicable "at the tap", and were adjusted
to account for dilution that could occur between the crib intake
on the River and the effluent point of discharge to the River.
In addition to effluent limits and risk-based standards, there is
a reporting requirement for non-regulated organic compounds in
the River of 0.5 ppb. This value is being used as the acceptable
concentration at the River crib for 1,2,3-trichloropropane
against which the effectiveness of the Interim Ground Water
Recovery System is being monitored.
The Pennsylvania ARAR for groundwater for hazardous substances is
that all groundwater must be remediated to "background" quality
as specified by 25 PA code Sections 264.90 through 264.100,
formerly 25 PA Code Section 75.264(n). The Commonwealth of
Pennsylvania also maintains that the requirement to remediate to
"background" is also found in other legal authorities.
Risk Characterization
Excess lifetime cancer risks for the Tyson's Site were determined
by multiplying the daily intake of chemicals from environmental
media by the cancer potency factors. These risks are
probabilities expressed in scientific notation (i.e., 1x10* ).
An excess lifetime cancer risk of IxlO"6 indicates that an
individual has a one in a million chance of developing cancer as
a result of site-related exposure to a carcinogen over a 70-year
lifetime. The EPA recommended upper bound for lifetime cancer
risks is between IxlO*4 and 1x10 however, the point of
departure, as described in the NCP, is considered to be 1x10* .
See 40CFR 300.430.
The estimated excess lifetime cancer risks for ingestion by an
off-site adult is 2x10 .
Potential concern for noncarcinogenic effects of a single
contaminant in a single medium is expressed as the hazard
quotient (HQ) (i.e., the ratio of the estimated intake derived
from the contaminant concentration in a given medium to the
contaminant's reference dose). The HQs for all contaminants in a
medium are added to obtain the Hazard Index (HI). The Hi
provides a reference point for gauging the significance of
multiple contaminant exposures within a single medium or across
media. A hazard index less than or equal to 1 indicates that
there is no significant risk of adverse health effects.
The HI derived for the groundwater medium is summarized below:
Exposure to Ground Water
POPULATION INGESTION
Offsite Adult 28
-------
39
The results of the estimated excess lifetime cancer risks and
noncarcinogenic hazard indices indicate the primary adverse
health risk posed by the Tyson's Site is due to potential
ingestion of offsite contaminated ground water from the deep
aquifer. Cancer risks for exposure to surface water (i.e.
Schuylkill River are within the EPA recommended guidelines. Thus,
both the cancer risk and Hazard Index justify a remedial action
at this site.
Actual or threatened releases of hazardous substances from this
Site, if not addressed by implementing the response action
selected in the ROD, may present an imminent and substantial
endangerment to public health, welfare, or the environment.
Description of Alternatives
As described in the Third Addendum Investigation Report,
hydraulic gradients north of the Schuylkill River are not fully
defined and the potential for discharge of contaminated
groundwater to the River or further northward migration of site-
related compounds cannot be fully quantified. Therefore, this
discussion of remedial alternatives extends only to the north
bank of the river. Some further investigation of the north side
of the river will be performed as part of the design and
construction of any alternative selected. The alternatives
evaluated include the best demonstrated available technology
(BOAT) to achieve the primary treatment level as defined by
effuent limitations. The four remedial alternatives evaluated in
the Focused FS are briefly summarized below:
Alternative il Mo Action
The Superfund program is required to evaluate the "No Action"
Alternative. For the Tyson's site, the No Action Alternative
would consist of no additional remedial action beyond the
operation of the Interim Ground Water Recovery and Treatment
System on the south bank of the river, and continued monitoring
of its effectiveness. This alternative would be selected only if
the Site posed little or no risk to public health or the
environment from hazardous substances as addressed in the
Superfund lav. Long-term monitoring (30 years) of the
groundwater, surface water and sediment would be performed.
There are no capital costs associated with the No Action
Alternative. The annual operation and maintenance costs including
monitoring are estimated to be $330,000. Present net worth for
30 years, using a 10% discount rate, would be $3,100,000.
-------
40
fa Extension of Interim
Ground Water Recovery
System
This alternative expands the existing interim ground water
recovery system from seven ground water recovery wells to
thirteen ground water recovery wells. Under this alternative,
three additional recovery wells would be installed to depths of
185 feet and four of the existing wells would be deepened to the
same depth to extend the ground water capture zone on the south
side of the river to its full designed vertical and horizontal
extent. Also, a long term (30 year) monitoring program consisting
of groundwater, surface water and sediment sampling would be
implemented.
The implementation requirements for this alternative are minimal
and the estimated implementation timeframe is expected to be 8
months. The groundwater restoration timeframe is at least 30
years. Institutional controls would also be implemented as part
of this alternative.
The capital cost for installation of the additional wells and
deepening the existing wells is estimated to be $550,000. The
annual operation and maintenance costs including monitoring are
estimated to be $440,000. Present net worth cost for 30 years,
using a 10% discount rate, would be $4,700,000.
Alternative J3A oroundwmter Recovery on
Barbadoes Island
This alternative includes the installation of recovery wells on
Barbadoes Island in addition to the extended well network on the
south side of the Schuylkill River, as discussed in alternative
2. This alternative would be designed to capture ground water
affected by site-related compounds emanating from sources on the
south side of the River and beneath Barbadoes Island. Treatment
of ground water recovered from wells on Barbadoes Island would
require piping the recovered ground water beneath the Schuylkill
River to the existing treatment facility on the south side of the
River. The existing treatment facility would need to be upgraded
to accommodate the additional volume.
The implementation requirements for this alternative include
gaining access to Barbadoes Island and obtaining permits from
the Delaware River Basin Commission (ORBC). The estimated
timeframe to implement this alternative is expected to be at
least 2 years. The groundwater restoration timeframe is at least
30 years. Institutional controls would also be implemented as
part of this alternative.
The estimated capital cost for this alternative would be
$2,200,000. The annual operation and maintenance costs including
-------
41
monitoring are estimated to be $840,000. Present net worth costs
for 30 years using a 10% discount rate would be $10,100,000.
Alternative • 3B Groundvater Recovery and
Treatment on
Barbadoea island
This alternative includes the installation of recovery wells on
Barbadoes Island in addition to the extended well network on the
south side of the Schuylkill River as discussed in alternative 2.
This alternative would also require the construction of a ground
water treatment facility on Barbadoes Island. The treatment
facility would be similar to the existing treatment facility on
the south side of the River. This alternative would also be
designed to capture ground water affected by site-related
compounds emanating from sources on the south side of the River
and beneath Barbadoes Island.
The estimated capital cost for this alternative would be
$5,200,000. The annual operation and maintenance costs including
monitoring are estimated to be $890,000. Present net worth cost
using a 10% discount rate would be $13,500,000.
The implementation requirements for this alternative include
gaining access to Barbadoes Island and obtaining permits from the
ORBC and the Army Corps of Engineers. The estimated timeframe to
implement this alternative is expected to be at least 2 years.
The groundwater restoration timeframe is at least 30 years.
Institutional controls would be implemented as part of this
alternative.
Comparative Analysis of Alternative
A detailed analysis was performed on the four alternatives using
the nine evaluation criteria presented in Table 5 in order to
select a remedy. The following is a summary of the comparison of
each alternatives' strength and weakness with respect to the nine
evaluation criteria.
Overall Protection of Human Health and the Environment
It is anticipated that the effluent limits (Table 2) for the
discharge of treated ground water would be met for all four
alternatives. As reported in the Third Addendum Investigation
Report, there is no apparent impact to river water quality from
groundwater discharging to the River from the vicinity of the
Island. This was concluded since the pumping on the south side
of the River has no apparent impact at the monitoring wells on
the Island and since the concentration of 1,2,3-trichloropropane
in the River as noted above has been essentially reduced to below
the 0.5 ppb reporting limit. Apparently, any groundwater in the
-------
Table 5 . DMCIIPTIOM OF lYftLOaTZOM CRITIftIA
Overall Protection of Hmfln ffealth and the Environmental -
addressee whether or not a remedy will: cleanup a site to within
the risk range; result in any unacceptable impacts; control the
inherent hazard (e.g., toxicity and mobility) associated with a
site; and minimize the short-term impacts associated with
cleaning up .the site.
Compliance with ARAB'S - addresses whether or not a remedy will
meet all the applicable or relevant and appropriate requirements
of other environmental statues and/or provide grounds for
invoking a waiver.
Lono— tar* Effectiveness and Permanence • refers to the ability of
a remedy to maintain reliable protection of human health and the
environment over time, once cleanup goals have been met.
refers to the anticipated performance of the treatment
technologies that may be employed in a remedy.
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 period until cleanup goals are achieved.
Implement ability - describes the technical and administrative
feasibility of a remedy, including the availability of materials
and services needed to implement the chosen solution.
£oj£ - includes the capital for materials, equipment, etc. and
the operation and maintenance cost.
Support Ayenev Acceptance - indicates whether, based on its
review of the RI,FS and £he Proposed Plan, the State concurs
with, opposes, or has no comment on the preferred alternative.
Acceptance - will be assessed in the Record of Decision
following a review of the public comments received on the Rl, ?s,
and the Proposed Plan.
-------
43
vicinity of the Island which discharges to the River does not
have a measurable impact on River water quality.
Alternatives 3A and 3B protect human health and the environment
by capturing ground water affected by site-related compounds
emanating from sources on the south side of the River and beneath
Barbados Island, thereby reducing the potential for further
migration of contaminants to the north side of the River.
Effluent limits for the "discharge of treated ground water to the
River would be met for. all four alternatives.
ComDliance with ARARs
SARA requires that remedial actions meet applicable or relevant
and appropriate requirements (ARARs) of other environmental laws.
These laws may include: The Toxic Substances Control Act, the
Clean Water Act, the Resource Conservation and Recovery Act, 'nd
any state law which has stricter requirements than the
corresponding federal law.
A "legally applicable" requirement is one which would legally
apply to the response action if that action were not taken
pursuant to Sections 104, 106, or 122 of CERCLA. A "relevant"
and appropriate requirement is one that, while not "applicable",
is designed to apply to problems sufficiently similar that their
application is appropriate. A list of ARAR's for each of the
considered alternatives is presented in Table 6. All of the
alternatives will meet ARAR's, and no waivers will be required.
Lena-Term Effectiveness and Permanence
The presence of the DNAPL in the deep aquifer will require that
ground water recovery to minimize the discharge of site-related
compounds to the River be conducted for a prolonged period. The
length of time required cannot be predicted at this time, but can
be evaluat~d at each of the five-year effectiveness reviews as
more information on the occurrence, nature, and recoverability of
DNAPLs becomes available, both for the site and in the scientific
community.
For each of the alternatives, long-term management will be
required, including monitoring of the effectiveness of the
recovery and treatment system. During operation of the treatment
system(s), monitoring of the River water and ground water quality
and treatment system effluent will be required. contingencies
for modifyinq any of the alternatives and, therefore, providing
additional protection to the river water receptor~ will be
required for each of the alternatives.
Reduction in Mobility. Toxicitv. or Volume lMTV)
The need to recover qround water establishes from the outset the
-------
Standard, Requirement
Criteria, or Limitation
Standards Applicable
to Generators of
Hazardous Waste
Standards Applicable
to Transporters of
lIazardous Waste
Occupational Safety
& Health Act
TABLE 6
FEDERAL ACTION SPECIFIC ARARs
/
Citation/Description
.'
42 U.S.C
Part 262
Subparts
A-E
49 C.F.R.
Part 263
29 U.S.C.
1919 &
1926
Establishes standards
for generators of
hazardous waste
Establishes standards
which apply to trans-
porters of hazardous
waste within the U.S.
Requlates worker
health' safety in
industry' con-
struct ion.
Aplicable/
Relevant and
Appropriate
No/Yes
I'!o/Yes
Yes/No
Commei1t
ARAR for all alter-
natives if remedial
action alternative
involves offsite '
transportation of
either soi~ or "
source material for
treatment or
disposal.
ARAR for all alter-
natives. If re-
medial action in-
volves offsite
transportation
of soil or source
material for treat-
ment or disposal.
ARAR for alter'-
natives 2,3A &
3B. Under 49 C.F.R.
369.38, require-
ments of the Act
apply to all re-
sponse activities
under the NCP
-
$:'-
$:'-
-------
TABLE 6 cont'd
FEDERAL ACTION SPECIFIC ARARs
Standard,
Tr iter ia.
Requirement
or Limitation
Citation Description
Appl(cable/
Relevant and
Appropr iate
Comment
Occupational
S. Health Act
Safety
Hazardous Materials
Transportation Act
Hazardous Materials
Transportat ion
Regulations
29 CFR Health & Safety
1910- standards for
120 or employees en-
54 FR gaged in hazardous
9294 waste operations.
49 U.S Regulates Trans-
1801-1813 portation of
hazardous materials
49 C.F.R. Regulates transporation
Parts 107, of hazardous materials.
171-177
Yes/No Applies to all re-
spones activities.
ARAR for all alter-
natives.
Yes/No Only if an alter-
native developed
would involve
transportation of
hazardous
materials. ARAR
for all alter-
natives .
Yes/No (Same as above)
Construction
Requirement
Army Corps Regulates Construction
of Engineers on wetland/floodplains
Section
ARAR for alter-
natives 3A and
3D since these
involves con-
struction of a
pipeline under
the River & con-
struction of a
treatment facility
on Barbadoes
Island respectively
-------
Standard, Requirement
Cri~~ri~l o~ ~imiation
PA Air Quality Standards
PA Air Quality Standards
PA Air Quality
Standards
-Backqround-
Quality for
Ground Water
TABLE 6 cont'd
STATE ARARs
- _~it~~io!!
Appl icable/
. Relevant and
'Q~~cripti~~ - Appropriat~
Chemical Specific
25 PA Code
Section
127.1 ,
Section
127.11
25 PA Code
Sections
123.1,123.2,
l23.3,and
123.41
25 PA Code
Section
121. 7
25 PA Code
Chaper
Section
264.90
throuqh
264.100
/
Establishes air
emmission control
Establishes air
emmission limit-
ations for fuqitive
odor and visible
emmissions
Prohibition of air
pollution
Hazardous sub-
stances in
qround water must
be remediated to
-backqround-
qua Ii ty
Yes/No
Yes/No
Yes/No
Yes/No
Comment
ARAR for a 11
alternatives
since contam-
inants will:b~
stripped by .
steam.
ARAR for all
alternatives
since contam-
inants will be
stripped.
~
a-.
ARAR for all
since con-
taminants will
be air stripped.
ARARs for all
alternatives
since contam-
inants of con-
cern exceed
background.
-------
Standard, Requirement
CriteLia. or Limiation
National Pollution
Discharge Elimination
System (NPDES)
Wa ter Qua li ty
Standards
lIazardous waste
qeneration, trans-
portation, storage
& treatment
Residual waste
generat. ion,
t ran s po r tat ion,
~; lor aqe r. t r ca tment .
Citation
/
TA.BLE 6 cont I d
STATE ARARs
Description
Chemical Specific
25 PA Code Establish Discharqe
Sections 92.1 Limitations
throuqh 92.79
25 PA Code
Section 93.1
throuqh 93.9
25 PA Code
sect ions.
26"
throuqh
265 & 279
25 PA Code
Sections
75.21
throuqh
75. 38
,Establish Water
Quality Standards
ACTION-SPECIFIC ARARs
Regulates hazardous
waste qeneration,
transportations,
storaqe & treatment
Requlates residual
generation, trans-
portation, storaqe
6. treatment
Appl icable/
Relevant and
Appropriate
Yes/No
Yes/No
Yes/No
Yes/No
Comment
-
-..
. ARAR for
. all alter-
natives
treated
qroundwater
will b~
discharqE;d
to Rive r
ARAR for
all alter-
natives
treated
. qroundwater
will be
discharqed
to River
ARARs for all
alternatives
since they in-
vole trans-
portation of
source material
ARARs for all
alternatives
since they in-
volve qeneration
6. transportation
of source
material
-------
1____-
Standard, Requirement,
Criteria, or Limitation
Wetlands & Floodplain
regulations
Dam Safety and
Waterway Manaqement
Scenic Rivers Act
TAB ['E 6 con t I d
LOCATION-SPECIFIC ARARs
Citation,
2S PA Code'
Sections
269.22
and
269.2]
2S PA Code
Section
HJS .1
throuqh
105.42]
25 PA Code
Section
269.50
Description
Prohibit siting
of treatment
facilities in
the 100 year
floodplain &
in wetland
areas
Regulates water
obstruction,
encroachments
and wetlands
Requirement
for con-
structing a
facility within
a protected
river corridor
Appl icable/
Relevant and
Appropriate
Yes/No
Yes/No
Yes/No
Comment
...
...
ARRA for alter-
]8 since this
involves con-
struction of
treatment facility.
ARAR for alter-
natives 3A & )8
since these in-
volve construction
of pipeline and
treatment facility
respectively
ARAR for alter-
natives 38 since
this involves
construction of
a treatment
facility.
-------
49
need for reducing the toxicity and volume of the site-related
compounds in the SchuylJcill River. Site-related compound
toxicity and volume in the river are reduced by ground water
recovery as shown by the proven effectiveness of the Interim
Ground Water Recovery System. All four alternatives incorporate
treatment. For the purpose of this FFS, it is anticipated that
treatment for Alternatives 3A and 3B will be Aqua Detox/ as it is
for Alternatives 1 and 2. It is anticipated that Aqua Detox will
continue to meet the limits established for the site. Upon
completion of additional studies to be conducted during the
design of a potential recovery system on the island, it may be
determined that another treatment alternative would be more
suitable for Altebrnaative 3A and 3B. Information such as volume
and concentration of compounds to be treated could dictate
choosing a more appropriate treatment system of the ground water
recovered from the island wells.
According to AWD Technologies, Inc. Aqua Detox is capable of
removing 92 of the 110 volatile compounds listed in CFR 40, July
1, 1986, by the EPA. Further, such systems have the demonstrated
capability to remove these compounds to the very low parts per
billion ppb range. This represents remediation that goes several
orders of magnitude beyond that of conventional stripping
systems, since conventional strippers will normally achieve only
80 to 95 percent removal, thus requiring additional treatment.
Typically, carbon beds are added to attain final water effluent
levels in the ppb range that are required by current
environmental standards. With Aqua Detox, carbon beds are
typically not required.
Short-Term Effectiveness
Each of the alternatives described consists of pumping and
treating ground water such that the water quality at the
Pennsylvania American Water Company crib intake is maintained at
the acceptable levels currently achieved by Alternative 1. From
the data obtained, the Interim Ground Water Recovery System
(Alternative 1) had the immediate impact of improving the River
water quality at the crib intake by reducing the 1,2,3-
trichloropropane concentration to below the 0.5 ppb reporting
limit. Alternatives 3A and 3B would provide prevention of
further migration of contaminants beyond the north bank of the
River.
For Alternatives 3A and 3B ground water treatment would include
either the construction of a treatment facility on Barbadoes
Island or piping recovered ground water across a navigable
section of the Schuylkill River to the treatment system on the
south side of the river. Short-term risks for workers would be
associated with the construction of the pipe line, the upgraded
treatment facility or a new treatment facility, and the
installation of wells on Barbadoes Island. For Alternatives 1
-------
50
and 2, the treatment facility has already been constructed.
Alternative 2 would require the installation of additional
recovery wells and, thus, there would be a need to safeguard the
health and safety of site workers during drilling and well
installation.
The risk of exposure to residuals generated during water
treatment is expectedte be-minimal, as organic residuals would
be taken off-site in closed containers for all of the
alternatives. If contaminated ground water is piped across the
Schuylkill River for Alternative 3B, the pipe could potentially
fail and contaminated water could be released directly to the
Schuylkill River. Precautions against failure of th piping
monitoring for leak detection would be required. .
Imt)lementabilitv
The Interim Ground Water Recovery System has been on-line for
over a year and as described previously, has been shown to be
effective at reducing the discharge from the deep aquifer of
site-related compounds to the river. The treatment system for
the Interim Ground Water Recovery System was sized to handle
anticipated flows and concentrations for the 13 well Full Ground
Water Recovery System so implementability of bringing on line the
additional wells on the south side of the River (Alternative 2)
would only require the installation of the wells and associated
pumps, piping, and hardware.
Implementing Alternatives 3A and 3B will require gaining access
to Barbadoes Island from Pennsylvania Electric Power Company
(PECO) for installation of recovery wells and possibly a
treatment facility. If the recovered ground water were to be
treated at a facility on the south side of the River, the water
would have~o be piped either over or under the river (cost
estimate~ have only been developed for installing a pipe under
the River). This will require extensive permitting and
monitoring. Permit requirements, such as NPDES, may need to be
revisited for Alternatives 2 and 3. A permit must also be
secured from the Delaware River Basin Commission (DRBC) for
Alternative 3A and 3B. A permit from the Army Corps of Engineer
will be required from the construction of pipleine as discribed
in Alternative 3A.
~
For Alternative 1, the estimated O&M costs are $330,000. For
Alternative 2, the estimated capital and 0&" costs for $520,000
and $440,000, respectively. For Alternative 3 in which a pipe is
used to bring recovered ground water from Barbadoes Island to the
existing Aqua Detox treatment facility, the estimated capital
costs and 0'" costs are $2.2 ~illion and $840,000, respectively.
If Alternative 3 includes the construction of an Aqua Detox
-------
51
treatment facility on Barbadoes Island, the estimated capital and
O&M costs for this alternative are about $5.2 million and
$890,000, respectively. All three alternatives will require
similar levels of monitoring to determine short- and long-term
effectiveness.
State Acceptance
The Commonwealth of Pennsylvania has concurred with the selected
remedial alternative.
Community Acceptance
Community acceptance is assessed in the attached Responsiveness
Summary. The Responsiveness Summary provides a thorough review
of the public comments received on the RI/FS and the Proposed
Plan, and U.S. EPA's and PADER's responses to the comments
received.
Description of the Selected Remedy
After careful consideration of the proposed remedial
alternatives, EPA's preferred alternative for the Tyson's site is
Alternative 3A, Groundwater Recovery on Barbadoes Island. Under
this alternative, groundwater recovery wells would be installed
on Barbadoes Island and also on the south side of the River to
extend the existing well network to 13 recovery wells. This
alternative would be designed to capture groundwater affected by
site-related compounds emanating from sources on the south side
of the River and beneath Barbadoes Island. The point of
compliance will be throughout the contaminated plume outside the
areas overlying known or suspected DNAPL sources. Contaminated
groundwater recovered from the wells installed on Barbadoes
Island would be piped beneath the Riv-r to the existing interim
ground water treatment system. This existing treatment system
would need to be upgraded to accommodate the additional volume.
This alternative would also include groundwater and surface water
monitoring to ensure the effectiveness of the groundwater
recovery and treatment as measured against the ARAR's in table 6
and to monitor the concentrations of contaminants in the ground
water and surface water. Groundwater and surface water sampling
will be performed for a period up to five years with formal
review of the Site after 5 years, pursuant to Section 121 (c) of
CERCLA. If, during this time, additional contamination is
detected, the risk posed by that contamination would be
determined and appropriate action taken.
In order to contain the dissolved plume immediately overlying the
DNAPL sources and to restore the other contaminated portion of
the aquifer to its beneficial use, the remediation system
implemented in this alternatives would operate until site-
specific remediation goals are achieved. Thus the aquifer would
-------
52
be remediated until the contaminant levels reach the MCLs, Non-
zero MCLGs, or background, whichever are lower.
If implementation of the selected remedy demonstrates, in
corroboration with hydrogeological and chemical evidence that it
will be technically impracticable to achieve and maintain the
remediation goals throughout the area of attainment, the EPA in
consultation with the Commonwealth of pennsylvania, intends to
amend the ROD or issue an Explanation of Significant Differences
to inform the Public of alternative groundwater goals.
It should be noted, however, that while EPA has selected the
Barbadoes Island as the location of the recovery system, a public
comment submitted on behalf of Ciba Geigy Cooperation (see the
Responsiveness Summary attachment to this ROD) has suggested that
another location for pumping the groundwater would be more
appropriate. While EPA does not have sufficient data to agree
with that suggestion in its selection of the remedy, EPAis aware
that Ciba-Geiby is collecting more data concerning that issue.
If as a result of that data, EPA decides to locate the recovery
system at another location, EPA will publish an explanation of
significant difference at that time.
The rationale for selection of this alternative is based on four
factors:
1. The extension of the interim groundwater recovery
system to 13 wells on the south side of the River will
further prevent the discharge of contaminated
groundwater to the River.
2. The installation of. ground water recovery wells on
Barbadoes Island will prevent the northward migration of
contaminated ground water.
,
3. The treating of the recovered ground water beneath
Barbadoes Island and on the south side of the river will
help in restoring the bedrock aquifer. .
4. The selected remedy offers the most cost-effective
solu~ion while still providing adequate protection of human
health and the environment.
Cost Estimate for Alternative 3A
Bsti.ated In.talled capital Costs
Installation of 13-well recovery well systems south
of river (cost detailed in Alternative II).
$520,000
Installation of 6 wells/header system to pipeline
beneat~ Schuylkill River.
$916,000
-------
53
Design and permitting (note a minimum of 130
to 150 day Pennsylvania review period)
70,000
Installation of double-walled line beneath Schuylkill
River (350 qpm maximum" designed flow)
Installation of instrumentation, pumps,
holding tank, and pump station.
450,000
75,000
System Upgrades
(influent, effluent pumps, and hardware)
Contingency (30' for new capital costs)
20,000
$184.500
Estimated Total Installed capital Costs
Estimated O'M costs
$2,235,5~0
Annual Treatment System O&M, including
electric power
propane (steam)
labor
maintenance
two laboratory sample/month*
disposal of organics**
$710,000
Maintenance of recovery wells,
submersible pumps
well header
well rebabilitation
Estimated ~otal O'M Costs
including:
$124,000
---------
$834,000
* Analytical cost $2,000/sample.
** Organic condensate disposal cost is based on 15
gallons/day production", which has a disposal cost of $6/gallon
StatutorY Determinations
EPAls primary responsibility at Superfund sites is to implement
remedial actions that are protective of human health and the
environment. section 121 CERCLA also establishes se~eral other
statutory requirements and preferences. The selected remedy must
be cost effective and utilize a permanent solution to the maximum
extent practicable. The selected remedial action must comply
with all applicable or relevant and appropriate requirements set
forth by State and Federal environmental regulations, unless such
-------
54
requirements are waived in accordace with CERCLA Section 121.
Finally, EPA must consider the statutory preference for remedial
actions that permanently reduce the toxicity, mobility, and
volume of the site-related wastes. The following sections
discuss how the selected remedy meets the statutory requirements
and preferences set f~rth by Section 121 of CERCLA.
Protection of Human -Hea}th and the Environment
The risk as assigned by EPA and associated with the contaminated
ground water on the north side of the River identified ingestion
of this groundwater as the only significant exposure pathway
having an adverse effect on human health or the environment. The
selected remedy would protect human health and the environment by
containing the contaminated ground water and preventing it from
migrating further north towards Norristown. Also, the selected
remedy would further prevent discharge of contaminated ground
water to the river.
ComDliance With ApDlicable or Relevant and ApDroDriate
Req)1irements
The selected remedial action will comply with all applicable or
relevant and appropriate location-, action-, and chemical-
specific requirements (ARARs). The Pennsylvania ARAR for ground
water for hazardous substances is that all ground water must be
remediated to "background" quality as specified by 25 Pa. Code
Sections 264.90 through 264.100. The Commonwealth of
Pennsylvania also maintains that the requirement to remediate to
background is also found in other legal authorities. A complete
listing of ARARs developed during the comparative analysis of
alternatives is presented in Table the ARARs specific to the
selected remedy are presented below.
Chemical-sDecific ARARs
- 25 PA Code Section 264.90 through 264.100 "Background"
quality for ground water remediation
- 25 PA Code Section 127.1, and 127.11
Quality Standards
- 25 pa Code Section 123.1, 123.2, 123.31 and 123.41,
Pennsylvania Air Quality Standards for establishing
emission limitations for fugitive, odor and visible
emissions.
pennsylvania Air
air
- 25 PA Code Section 121.7, Prohibition of Air Pollution
- 25 PA Code Sections 92.1 through 92.79, National Pollution
Discharge Elimination System (NPDES) for treated groundwater
discharge limitations.
-------
55
- 25 PA Code Sections 93.1 through 93.9, Establish water
Quality Standards.
Location SDecific ARARs.
- 25 PA Code Sections 269.22 and 269.23, prohibits siting of
treatment facilities iri the 100-year floodplain and in
wetland areas, respectively.
- 25 PA Code Section 105.1 through 105.423 regulates water
obstruction, encroachments, and wetlands.
- Pennsylvania Scenic Rivers Act and 25 PA Code Section 269.50
requirements for constructing a facility within a protected
river corridor.
Action sDecific ARARs
- 25 PA Code Sections 260 through 265, and Section 270
regulates hazardous waste generation, transportation,
storage and treatment
- 25 PA Code Sections 75.21 through 75.38, regulates
residual waste generation, transportation, storage and
treatment
- 29 CFR Parts 1910 and 1926, Occupational Health and
Safety Act requ~rements are applicable to all response
activities
Cost-Effectiveness
The selected remedy is cost-effective because it has been
determined to provide overall effectiveness proportional to its
costs, thse net present worth value being $10,100,000. The.
selected remedy is less costly than alternative 38 and provides a
level of protection of human health comparable to that provided
by other remedies.
Utilization of Permanent Solutions to the Maximum Extent
Practicable
EPA has determined that the selected remedy represents the
maximum extent to which permanent treatment technologies can be
utilized in a cost effective manner for the Tyson's Site. Of
those alternatives that are protective of human health and the
environment and comply with ARARs, the EPA has determined that
the selected remedy provides the best balance in terms of short-
term effectiveness; imp1ementabi1ity: cost; reduction in
-------
56
The selected remedy does offer a high degree of long term
effectiveness and it will significantly reduce the risks to human
health posed by the contaminated ground water. The excess human
cancer risk at the North Bank of the Schuylkill river has been
estimated at 2xlO~2 which is above EPA's recommended upper bound
of IxlO"4 to 1X10"6 Due to the relative high risk associated with
the contaminated ground-water, EPA has determined that the use of
the selected remedy is justifiable. Although 3B offers a
comparable level of protection of human health and the
environment, the EPA has sleeted alternative 3A, which can be
implemented relatively quickly; will have little or no adverse
effects on the surrounding community; and will cost considerably
less than alternative 3B.
Preference for Treatment
By recovering and treating the ground water with steam-stripping
process the selected remedy addresses one of the principal
threats posed by the site threough the use of treatment
technologies. Therefore, the statutory preference for remedies
that employ treatment as a principal element is satisfied.
Documentation of Significant Changes
The preferred alternative originally proposed in the Proposed
Plan is also the preferred alternative selected in the ROD.
There have been no significant changes made to the selected
remedy in the time period between the issuance of the Proposed
Plan on July 23, 1990 and the signing of the ROD approximately
ten weeks later.
It should be noted, however that while EPA has selected the
Barbadoes Island as the location of the recovery system, a public
comment submitted on behalf of Ciba-Geigy Corporation (see the
Responsiveness Summary attachment to this ROD) has suggested that
another location for pumping the groundwater would be more
appropriate. While EPA does not have sufficient data to agree
with that suggestion in its selection of the remedy, EPA is aware
that Ciba-G«igy is collecting more data concerning that issue.
If as a result of that data, EPA decides to locate the recovery
system at another location, EPA will publish an explanation of
significant differences at that time.
-------
RESPONS:VENESS SU~~RY
OPERABLE UNIT :3 - TYSON'S DISPOSAL SITE
This community relations responsiveness summary is divided into t~e
following sections:
section I
overview - A discussion of EPA's prefer~ed remedial
alternative for Operable Unit #3 at Tyson's Disposal
Site and the public's response to this alternative.
Section II
Background of community Involvement and Concerns - A
discussion of the history of community interest ar:d
concerns raised during remedial planning activities at
Tyson's Disposal Site.
sectinn
III Summary of Major Comments Received During the PUblic
M.etinq, PUblic Comment Period and Aqency Responses -
A summary of comments and responses categorized by
topic.
I.
overview
EPA's preferred alternative for Operable Unit #3 of the Tyson's
Disposal Site (the Site) is alt~rnative ;3A, Ground Water Recove~y
on Barbados Island, outlined in the Proposed Remedial Action Plan.
Operable Unit #3 addresses further remediation of the contaminated
ground water which has migrated beneath, and as far as, the nort~
bank of the Schuylkill River.
The preferred alternative calls for the expansion of the grour:d
water recovery system on the south side of the Schuylkill River
from seven wells to thirteen wells and the installation of recovery
wells on Barbados Island. This alternative would be designed to
capture ground water affected by Site-related compounds emanating
from sources on the south side of the river and beneath Barbados
Island. Treatment of ground water recovered from wells on Barbados
Island would"require piping the recovered ground water beneath the
SChuylkill,River to the existing treatment facility on the south
side of the'river. The existing treatment facility would need to
be upgraded to accommodate the additional volume. This alternative
would also include ground water and surface water monitoring and
analysis to ensure the effectiveness of the ground water recovery
and treatment. Sampling will be performed for a period up to five
years with a formal review taking place after five years. If,
during this sampling, additional contamination is detected, the
risk posed by that contamination would be determined and the
appropriate action taken. '
Based on currently available information, EPA anticipates that this
alternative will be protective of human health and the environment.
1
-------
:u=:~; .:~~ ;c~:~= ==~=e~~ ;a=~=c, ~r~~~a~ ==~=e~~~ =a;~=~:~~ :~~
selec~ion of a =emedial al~e=~a~ive ~e=e =eceived t~ :?A. ~ =~~:::
~e~-~ng was also held on August 9, 1990. Generally, ~he =eside~~$
se~ ;d to be in agreement with the Proposed Plan. Four reside~~s
voiced their questions and concerns to EPA staff during the
meeting. These comments and EPA's answers will be summarized in
Section III of this report.
II.
BACKGROUND OF COHMUNITY INVOLVEMENT AND CONCERNS
Community interest in the Tyson's Disposal Site began in 1983 when
EPA received an anonymous complaint from a citizen regarding odors
emanating from the Site. This complaint prompted the ir.i~.:.al
investigation of the Site.
Since 1983, EPA has conducted a series of Remedial
Investigations/Feasibility Studies (RI/FS) on the Site's operable
units and has issued Records of Decision (RODs) for Operable Unit
;1, the on-Site area that encompasses the lagoons, and Operable
Uni t #2, which consists of contaminated ground water in the bee. :)ck
aquifer up to the south bank of the Schulykill River.
Upper Merion Township officials have been involved with all aspects
of the Site, although residents living near the Site have been
mostly interested in the former lagoon area of the Site. Public
meetings were held before the first ROD was issued in 1985
announcing soil excavation as the selected cleanup alternative for
the on-Site area. There was also community interest in 1987 when
EPA revised the ROD for Operable Unit #1 to include vacuum soil
extraction as the preferred alternative as opposed to soil
excavation. A public meeting was held at that time and a
responsiveness summary was written to answer the public's questions
and concerns.
There was not much community interest in the off-Site areas,
Operable Unit #2, when EPA placed newspaper advertisements
describing~he cleanup alternatives in September 1988. No
comments 'were received during the public comment period and
although t~e opportunity for a public meeting was provided, the
communi ty did not express interest in having a meeting. The
alternative selected tor the cleanup of Operable Unit #2 called for
air and steam stripping of contaminated ground water. The cleanup
commenced in November 1988.
However, since the construction of the air stripping tower
(Operable Unit #2) located near the Site on the south side of the
river, concerns have been voiced by members of the community who
live closest to the tower. These residents feel that the height 0:
the tower is unsightly and could reduce the real estate values of
their properties. EPA staff have met with the spokesperson for this
group and have agreed to review the specific complaints that have
been made, review EPA's past efforts to involve the community and
2
-------
=onsi::.e~
-....ha-:.
ac-:.:~~ -:.~ -:.ake ~~ ~esponse ~o ~he dissa-:.~s:=c~::~.
A public meeting on the cleanup alternatives selected for Operable
Unit ~3 was held on August 9, 1990. Approximately twenty people
attended the meeting.
The concerns voiced at the public meeting and the comments received
during the public comment period about EPA's preferred alternative,
other remedial alternative preferences and EPA' s responses are
described below. .
III.
SUMMARY OF KAJOR COMMENTS RECEIVED DURING THE PUBLIC MEETING,
OPEN PUBLIC COMMENT PERIOD AND AGENCY RESPONSES
EPA'S PREFERRED ALTERNATIVE
1. Comme.nts were made regarding the visual impact of the preferred
remedial alternative #3A. Could the air stripping tower perform
the same function if it were located on Barbados Island as opposed
to the south side of the river? Is there an alternative cleanup
technology available that would not require the 40-foot air
stripping tower already in place?
EPA Response: The implementation of the preferred al ternati ve will
not require an extension of the present tower, heightening of the
tower or the installation of another tower. The modification to
the present treatment facility will involve installing some
addi tional pumps on Barbados Island or on the south side of the
river which will not be noticeable.
It is reasonable to say that yes, the tower could be located on
Barbados Island and perform the same function. However, at this
time, everything is situated on the south side of the river because
when the tower was installed we did not know what was going on
beneath the river on the north side, and it was imperative that we
prevent any (urther discharge of ground water to the river.
There are 'other treatment technologies for contaminated ground
water. However, at the time, EPA felt that the air stripping tower
was the best alternative for Operable Unit #2.
2. A t:esic1ent asked if any ground water receptors other than
Norristown State Hospital have been identified in the area? And
have any other ground water receptors been identified that may have
contaminants associated with the Tyson Disposal Site?
EPA Response: There were a few residents on the south side of the
river who still have ground water wells. Those wells were sampled
and found to be clean. We have identified numerous wells on the
Norristown side, some of which were installed in the 1800s that do
not exist anymore. Norristown State Hospital and a bakery, who
3
-------
ie~:a~ ~~ !c=es~ ~: 3a~p:~ ~~a ~e::,
~ecep~=rs ~ha~ ~ave been iden~ified.
~-~ _._~ -."""..... --,1-
-- - --..- -.,,~.: '-of-
---..--
- - ... -..-
---.c ~ =:'
3. Do you have any idea by what mechanism the contarni~ation fro~
the Tyson's Disposal Site would have been drawn in the northeast
direction of the Site under and across from the river?
EPA Response: We believe that the DNAPLs and ground water are
following the fracture system in the bedrock that goes to several
hundred feet below the surface. There was a stronq gradient on the
south side that discharged ground water to the river and there was
some under flow beneath the river which continues to migrate tOward
the north. This was determined during the remedial investigation.
The contamination may have moved naturally towards the north side
of the river or may have been induced by pumping centers on the
north side of the river. Without additional wells it cannot be
definitively stated.
4. Is that flow going toward Norristown State Hospital?
EPA Response: We're not sure. Without wells placed further north,
we can't get flow patterns to see exactly where the ground water is
. flowing. We're going to put additional wells in between the north
bank of the river and Norristown State Hospital to see if ground
water is continuing to migrate northward or if there is some sort
of divide where ground water will actually move toward the river.
Until we install those additional wells north of the river, we
can't be sure where the hydraulic gradient is.
5. In a fractured rock system, isn't it possible that water might
flow for a distance in one direction and then, intercepting a
fracture, flow in another direction?
EPA Response: Yes, if there are major structural features.
definition of flow and fracture is very difficult.
6. Has there, been any attempt to identify any structural features
that flow from the Site or from an extension of this Site that goes
in another direction? And, is there any intention to look in any
other direction other than north for such fracture and migration.
The
EPA Response: Yes, a fracture trace analysis was conducted in 1987
and wells were located as best as possible to intercept these
fractures. One of the difficulties we've had with understanding
what is happening with the gradients and directions of ground water
flow north of the river is that our wells are installed in a line
on the north bank of the Schuylkill River. Therefore, we don't
have a three dimensional picture of what is happening. It is hoped
that this next round of well installation will be able to develop
that information.
.:.
-------
. .- » /=- --• / .. ...=
resident askac" fcr ar. axplar.aticn of hov the risk assessments
listed in the Prcposed Remedial Plan is derived and en whaz
particular contaminants they are based?
EPA Response: The risks at the Tyson's Disposal Site are
almost entirely attributable to 1,2,3 - Trichloropropane. Although
EPA has no high quality data indicating that this compound is a
carcinogen, EPA has assumed it has a carcinogenic potency similar
to that of analogous chlorinated solvents. EPA has applied this
carcinogenic potency factor to an assumed residential use of
contaminated ground -wate,r- involving ingestion of two liters per day
for a 70 year lifetime.
8. Have tests been taken on areas that lie south of the Site? If
so, has there been any migration of contaminants to the south?
EPA Response: The ground water flow direction is to the north on
the south side of the river. Upgradient wells (south of the Site)
do not indicate Site contamination.
The Upper Merion Township Advisory Committee had several comments
and questions regarding the alternatives described in EPA's
Proposed Remedial Action Plan. The committee found Alternative =1,
No Action, and Alternative #2, Extension of Interim Ground Water
Recovery System unacceptable. Also, before endorsing either
Alternative #3A or #3B, the committee would like answers to the
following questions:
1. What cautionary design and operation procedures have been
considered to minimize the possibility of a leak and/or rupture of
the proposed pipeline under the Schuylkill River in association
with Alternative #3A, and what type of monitoring will be
associated to ensure that a leak has not occurred?
EPA Response: During the pipeline design phase, we will look at
leak warning systems for the pipeline that will react if a rupture
or leak should occur.
2. Will the pipe under the river be constructed of double piping,
i.e., a pipe within a pipe?
EPA Response: We will also look into the feasibility and cost of
construction for double pipe during the design phase.
3. Will the ground water extracted from the wells be pushed
through the pipeline using pumps on Barbados Island, thereby
putting the transmitted fluid under positive pressure, or will
additional pumps be installed on the south side of the river to
pull the fluid through the pipeline, thereby putting the
transmitted fluid under negative pressure?
-------
ZPA ~esponsa: :~es~ :;~::~~
phase 0: ~~e =leanup.
"::_- =e ==~s:je=~~
. .
~l':= :::~ ~::;
.::.=s:~:-.
~. Have the costs of pe~it~:~g a pipeline under the Schuylkil:
River been included in the projected economic cost for Alternative
=3A?
EPA Response:
analysis.
5. Have the potentiai econQmic and environmental costs associated
with a potential leak and/or rupture of the pipeline been taken
into consideration in the development of the cost estimate? In
particular, do the potential economic and environmental costs of a
pipeline leak/rupture negate the $3,400,000 difference in projected
costs between Alternative #3A and #3B1
Yes, the permit costs were included in the cost
EPA Response:" Costs associated with leak and/or rupture have not
been developed at this time. This analysis can be performed dur ing
the design phase of the cleanup.
6. Is there a substantial difference in the estimated tiIte to
fully activate Alternative #3A versus Alternative #3B1 If so, what
are these projected times? Was estimated time to fully activate
treatment considered in EPA's recommendation of Alternative =3A?
EPA Response: No, there is not a substantial time difference
involved. Both of the Alternatives will take at least two years to
fully activate.
7. There is evidence indicating that pollutants have spread
northward, beyond Barbados Island. Was the possibility that
additional ground water treatment on the north side of the river
could eventually be necessary taken into consideration in EPA's
recommendation of Alternative .#3A? If so, what was the nature of
this analysis?
EPA ReapoDs.: EPA is interested in long-term control of the
dissolved plume associated with the DNAPL source under Barbados
Island. Ground water pumping and treatment on the north side of
the river may augment or replace pumping on Barbados Island as. long
as sufficient hydraulic control can be maintained over the
contaminant plume. Once the additional investigations on the north
side of the river have been completed, any necessary changes in the
location ot pumping wells can be made at that time.
REMEDIAL ALTERNATIVE PREFERENCE
Several comments were received stating a preference for Alternative
#2, Extension of Interim Ground Water Recovery System as opposed to
EPA's preferred Alternative #3A, Ground Water Recovery on Barbados
6
-------
Is:ar.c. These =ommen~3 =ea:
and are summarized below:
:-/:. ~::
=c-:::
;:c:':c::,
~r:= :=c:::::..=~-
. .- _0..- .
------
1. Comments were received stating that EPA' s selection 0: the
preferred al ternati ve for Operable Unit =#) is contrary to the
Na~ional Contingency Plan (NCP) because it does not u~ilize
containment and is inconsistent with or precludes implementation of
the expected final remedy.
EPA Response: It appears that the objectives of the selected
remedy to pump and ~reat ground water at Barbados Island may not be
fully understood. Th~ Remedial Investigation/Feasibility Study
documented ground water contamination in the deep portion of the
bedrock aquifer which is currently used as a potable water supply
source. EPA, in accordance with the NCP, intends to restore the
aquifer to its beneficial uses where technically feasible and
utilize containment in those ar~as where restoration is not
appropriate.
The notion of containment is the issue most central to the r:.~edy
selected by EPA. The Remedial Investigation reported that DNAPLs
exist under Barbados Island and that substantial quantities of the
DNAPL constituents are present as dissolved contaminants in the
ground water under the island and on the north banks of the
Schuylkill River. Present understanding of DNAPL existence
indicates that the DNAPL may be present in pools, or as coatings on
fractures and pore space and will continue to act as a source for
dissolved contaminants which may then move with ground water flow.
It is clear that the DNAPL residing in the aquifer may act as a
source for many, many years and restoration of that portion of the
aquifer is most probably unattainable.
However, management of the dissolved plume can be accomplished so
that further spreading is mitigated and areas of the aquifer which
may be actually or potentially down gradient of the DNAPL source
are protected. To best manage and confine the plume in the
aquifer, EPA chose a pumping location as close as possible to the
continual source area. Neither the hydraulics nor the limit of
contamination on the north side of the river have been adequately
defined. It is not known if a natural gradient or one artificially
induced has drawn contamination to the north side of the river.
However, as long as DNAPLs exist under Barbados Island and are not
present under the north side of the river (as reported in the RI/FS
document), a plume of dissolved contamination, which may move
naturally or could potentially move under pumping conditions,
exists in the aquifer. To adequately control this plume of
dissolved contaminants, EPA believes pumping and treating is best
managed closest to its source area at Barbados Island. This action
can thereby prevent the plume's further migration, reduce risk at
locations where the plume currently exists and restore and maintain
as much of the aquifer as possible to useable conditions.
7
-------
2. A =o~~en~ ~ues~ionec Nhethe~ pu~pi~g ~n 3a~bados :s:a~c
provide fur~her measures of protec~ion :or the ~iver Na~er.
."'---
EPA RespoDse:
Refer to the response given to question #1 above.
3. A comment was received which stated that there are no health
based risks or environmental reasons for taking any further action
to address the impact of ground water discharge into the river.
EPA RespoDse: One of EPA's primary objectives is to contain the
contaminant plume in 'the -aquifer. At this time, the extent of that
plume is still not entirely known. That being the case, potential
discharges to the river from the aquifer that we have not yet
discovered may raise these health based risks and environmental
concerns.
4. Several comments were made stating that the presence of DNAPLs
in the bedrock aquifer precludes restoration of the aquifer as a
goal that can be accomplished in the foreseeable future.
EPA RespoDse: As stated in response to Question #1, the goal of
this selected alternative is to manage the dissolved plume
associated with the DNAPL contamination. It is clear that the
presence of DNAPLs in the aquifer may act as a source of
contamination for a very long time and that restoration of that
part of the aquifer is most probably unattainable.
5. A comment was received which stated that the selected
alternative is unnecessary because the recovery well system on the
south side of the river has blocked the flow of contaminated water
to the river and there are no present uses of the ground water on
Barbados Island or on the north side of the river.
BPA aespoDse: This statement is incorrect. While the "south side"
recovery well system blocks flow from the "south side", there is
contaminated ground water that has already migrated beyond that
point in a" northerly direction under the river. Norristown State
Hospital.,located on the north side of the river is a ground water
receptor. '
6. A comment was received stating that the installation of ground
water recovery wells on Barbados Island prior to obtaining a more
complete understanding of the dynamics of ground water flow and its
impact on the presence of Site-related compounds beneath the island
and on the north side of the river would be premature and may
impact the overall effectiveness of an ultimate ground water
remedy. It was stated that disturbing the bedrock aquifer system
by pumping on Barbados Island could prevent us from ever
understanding the mechanisms responsible for the presence of Site-
related compounds north of the river.
8
-------
EPA Response: EPA believes that containment remedies can best be
managed by locating them closest to the source area; however, if
Ciba Geigy and their technical support staff can prove that
sufficient hydraulic control of the contaminant plume can be
maintained without pumping on Barbados Island, then the pumping
wells can be relocated during the design phase of the remedial
action.
Furthermore, if new information can be provided showing that
pumping on Barbados Island would be detrimental to our objectives
stated above, the pumping.we11s could then also be relocated during
the design phase of the remedial action. These considerations have
been included in the remedy selection in the Record of Decision.
As a final point, the selected preferred alternative was initially
presented and supported in the Feasibility Study provided to EPA by
Ciba Geigy.
7. A comment was made questioning whether pumping ground water
from the full recovery system on the south side of the river and/or
whether pumping ground water from wells on Barbados Island will
have an impact on the presence of Site-related compounds on the
island and north of the river.
EPA Response: As Dr. Cherry states in his comments to EPA, "The
lack of hydraulic response in piezometers on Barbados Island and on
the north side of the river due to the shutdown of the Interim
Ground Water Recovery System on the south side of the river
suggests poor hydraulic connection beneath the river."
8. A comment was received stating that ground water pumping
remedies should be currently focused on reducing the potential
effects on existing identified receptors and then on protection of
future possible receptors because we have been unable to identify
any ground water users north of the Schuylkill River except for the
Norristown State Hospital.
EPA Responses This approach is inconsistent with EPA's policy.and
the requirements under the Superfund Amendments and Reauthorization
Act (SARA) that state the cleanup goal is to restore the aquifer to
its current and future potential beneficial uses.
9. One reviewer provided hypothetical scenarios of flow on the
north side of the river either towards the river or away from the
river and indicated that the selected remedy is not appropriate for
either scenario. The review also stated that under flow conditions
toward the river, no further remedial action may be necessary.
EPA Response: Since these scenarios are merely speculative and
additional information will be gained during the investigations on
-------
the north side of the river, it is no~ feasible at this ~irne ~c
make any conclusions regarding the use of institutional controls or
pumping solely on the north side of the river.
10. Concerns have been raised that pumping near the DNAPL
previously identified under Barbados Island might destabilize the
DNAPL contamination in such a way as to cause contamination of the
Schulykill River.
EPA Response: This is a curious concern because Ciba Geigy is
currently pumping ~nd'planning to increase pumping on the south
side of the river where ~he 'presence of DNAPLs have been confirmed.
However, the reviewer.has referenced a document, prepared for the
reviewer, that describes the mechanisms of DNAPL destabilization
which has not yet been made available to EPA. Once this document
has been published any relevant implications for the Tyson's
Disposal Site will be evaluated at that time. -' ,', .
."
. '.
:t.~~
"
~
10
. . r. ~. ~ \. J' >
------- |