United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R06-87/016
November 1986
SEP A
Superfund
Record of Decision:
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TeCHNICAL REPORT DATA
(Please read Insrructlons all the revene berOTe complering)
,. REIIORT NO. 12. 3. RECIPIENT'S ACCESSION NO.
EPA/ROD/R06-86/0l6
.. TITLe AND SU8TITLE 15. RepORT DATE
SUPERFUND RECORD OF DECISION November 14, 1986
Bayou Sorrel, LA 8. PERFORMING ORGANIZATION CODE
First Remedial Action
7. AUTHOR IS) 8. PERFORMING ORGANIZATION REPORT NO.
9. peRFORMING ORGANIZATION NAMe AND ADDRess 10. PROGRAM ELEMENT NO.
11. I;ONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORT AND PERIOD COVEREC
U.S. Environmental Protection Agency Final ROD ReDort
401 M Street, S.W. 1.. SPONSORING AGeNCY CODE
Washington, D.C. 20460 800/00
115. SUPIILEMENTARY NOTES
18. A8STRACT
The Bayou Sorrel site is located in Iberville Parish, Louisiana approximately 20
miles southwest of Baton Rouge, LA. Fifty acres of the 265-acre site have been used for
waste disposal. The waste disposal areas consist of four landfills: a spent lime cell,
a crushed drum cell, four covered liquid waste ponds, and a land farm. The remaining
acres are covered by dense brush and trees. The enti~e site has a marshy, bayou-type
environment and is prone to flooding and poor drainage. Early in 1977, the
Enviionmental Purification Advancement Corporation (EPAC) began operating the Bayou
Sorrel site. A sister firm, Clean Land Air Water, Inc. (CLAW) operated an injection well
approximately six miles south of the site. EPAC operations included landfarming, open
liquid impoundments, drum burial and landfilling of chemically fixated wastes. The
fixation process is unknown but may have included lime, cement, and native soils. EPAC
and CLAW were two separate operations, however, it was suggested that wastes from the
injection well were diverted to EPAC when process problems at the well caused a
bottleneck. In the summer of 1978, a truck driver died at the site. It is suspected he
died as a result of inhaling hydrogen sulfide gas created when liquid wastes were dumped
into the receiving pond. State and Federal regulatory officials inspected the site
following this incident. Unknown materials were found in large, open unpermitted ponds
and the site was ordered closed. Approximately 36,400 cubic yards of wastes remain
(See Attached Sheet)
17. . KEY WORDS AND DOCUMENT ANALYSIS
DISC..II"TO... b.IDeNTIFIERS/OPEN ENDED TERMS C. CDSATI Field/Croup
Record of Decision
Bayou Sorrel, LA
First Remedial Action
Contaminated Media: gw, surface soils,
Key contaminants: hydrogen sulfide, pesticid :!s,
herbicides, organics, VOCs
18. CISTRI8UTIDN STATEMENT 19. SECURITY CLASS IT/lis Reporr} 21. NO. OF PAGES
None 58
20. seCURITY CLASS ITllis ptlgel 22. PRICE
I None
e,. '.,111 2220-1 (Rn. .-71)
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EPA/ROD/R06-86/0l6
Bayou Sorrel, LA
First Remedial Action
16.
ABSTRACT (continued)
onsite following the September 1978 closure activities. The primary
contaminants of concern include: sulfide wastes: process wastes from
pesticide/herbicide manufacture: and spent wash solutions. Some localized
surface soil contamination with herbicides and other organic compounds was
found at the south end of the site.
The selected remedial action includes: regrading the site to control
runoff, limit cap erosion, limit surface water ponding and divert storm
water from waste areas: covering former disposal areas with RCRA
top-soil/geomembrane/clay caps: installing a sand/geofabric pore water
drainage layer above the wastes and below the cap, and including a venting
system to reduce buildup of methane and other gases beneath the cap:
consolidating all miscellaneous wastes outside currently capped areas under
the new caps for grading and fill purposes or disposing of wastes at an
offsite facility: installing a 30-feet deep slurry wall around the former
landfill area and constructing a shallow slurry wall around the former Pond
4 area: fencing all capped areas to restrict access to disposal areas and
constructing gravel access roads around fenced areas to allow continued
recreational use of adjacent lands and borrow lake while diverting traffic
around and away from the disposal areas; and installing a ground water
monitoring system. The estimated capital cost for this remedy is
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'41 MIf1I~C.
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION VI,
120' ELM STREET
DALLAS. TEXA. 75270
RECORD OF DECISION
, Site
.
Bayou Sorrel Site located in Iberville Parish, Louisiana, approximately
6 miles north of Bayou Sorrel, Louisiana. .
DOCUMENTS REVIEWED
I 'am basing my decision primarily on the following documents describing
the analysis of the cost and effectiveness of the Remedial Alternatives
for tne Bayou Sorrel site.
Environmental Protection Agency, 1985. "Remedial Investigation Report,
Bayou Sorrel Site, Bayou Sorrel, Louisiana.1I Volumes I and II. Prepared
by CHZM Hi 'II .
Environmental Protection Agency, 1986.
Sorrel Site. Bayou Sorrel, Louisiana."
"Endangerment Assessment, Bayou
Prepared by Life Systems, Inc.
Environmental Protection Agency, 1986.
Sorrel Site, Bayou Sorrel, Louisiana."
Inc.
IIFe-asibility Study Report, Bayou
Prepared by CHZM Hill and SRW,
Summary of Remedial Alternative Sp.lection (Attached)
Summary of Public Comments Received During Public Comment Period and
Agency Response (Attached)
DESCRIPTION OF THE REMEDY
The Feasibility Study evaluated alternative treatment technologies
including incineration and biological treatment. These technologies
were not retained ~ue to engineering impracticability (a detailed
discussion can be found in the Summary of Remedial Alternative Selection).
o Regrading of the site to control runoff, limit cap erosion, limit
surface water ponding and divert storm water from waste areas.
o Former disposal areas will be covered with RCRA top-soil/geomembrane/clay
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2
o
A sand/geofabric pore water drainage layer will be installed above
the wastes and below the cap. This layer will be connected to a
system of pipes, manholes, pumps and tanks which will collect an0
store the liquids from this drainage layer.
o A venting system will be included in the cap to reduce the buildup
of methane and other gases beneath the cap.
o
All miscellaneous wastes outside currently capped areas would be
consolidated under the new caps for grading and fill purposes or
disposed of at an off-site facility.
A slurry wall approximately 30 feet deep (actual depth to be determined
during final design) would be installed around the former landfill
area. Also, a shallow slurry wall will be constructed around the
former pond 4 area.
o
o
All cap~ed areas will be fenced to restrict access to disposal areas.
Gravel access roads will be constructed around fenced areas to allow
continued recreational use of adjacent lands and borrow lake while
diverting traffic around and away from the disposal areas.
o
Installation of a groundwater monitoring system to monitor the
effectiveness of the remedy.
Decision
Consistent with the Comprehensive Environmental Response, Compensation,
and Liability Act of 1980 and the National Oil and Hazardous Substances
Contingency Plan (40 CFR Part 300), I select the remedy described above
for the Bayou Sorrel site. I have determined that this remedy is cost-
eff~ctive and is protective of public health and welfare and the
environment. The action will require operation and maintenance to
maintain the effectiveness of the remedy. Since wastes will be left on-
site, the remedial action will be reviewed every five years to assure
that th~ remedy is still protecting public health and the environment.
The State of Louisiana has been consulted on the remedy. I have
considered Section 121 of the Superfund Amendments and Reauthorization
Act of 1986 (SARA), including the cleanup standards thereof, and certify
that the portion of the remedial action covered'by this Record of
Decision (ROD) complies to the maximum extent practicable with Section
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I
"
3
If negotiations are successful I potentially responsible parties (PRPs)
will enter into a Consent Decree with EPA authorizing the PRPs to
im~lement the remedial action. In the event that negotiations are
unsuccessful, litigation wi11 be pursued by EPA and the Department of
Justice in an effort to secure perform~~~~a~~. ,
olfr./i J9?,6 a ces Eo P ,~
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. .
Summary of Remedial Alternative Selection
BAYOU SORREL SITE
Iberville Parish, Louisiana
March 1986
s~i~' Lbt~tibh:~hd' Dest~i~tibri
The ~ayou Sorrel Site is located in Iberville Parish, Louisiana, approximately
20 miles southwest of Baton Rouge, Louisiana, about six miles ~orthwest of
the town of Bayou Sorrel (Figure 1). The west border of the site is bound by
a man-made drainage feature called "Borrow River". About 100 yards west of
Borrow River is the Atchafalaya Basin Protection Levee, while the north and
east sides of the site are bound by the Upper Grand River and Pat Bayou,
respectively. Undeveloped swamp land is adjacent to the site on the south
(Figure 1). Access to the site from the north is along the unpaved levee
road 14 miles south of its intersection with Interstate 10 at Ramah, Louisiana,
while access from the south is along the same unpaved levee road six miles
north of the town of Bayou Sorrel. The Upper Grand River provides barge
access to the site.
The Bayou Sorrel Site, as shown on Figure 2 is a "Tn shaped, relatively flat
parcel of land encompassing about 265 acres. Approximateiy 50 of the 265
acres were actually used for waste disposal. The waste disposal areas consist
bf four landfills including the spent lime cell and the crushed drum
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EPAC operations included landfarming, open liquid impoundments, drum
burial, and landfilling of "chemically fixated" wastes. Louisiana Department
of Environmental Quality (LDEQ) officials report that all of these except
the open pond were permitted by the State. The fixation process is
unknown but may have included lime, cement, and native soils. EPAC was
supposedly a separate operation from CLAW. However, court testimony
by former employees suggests that wastes were diverted from the injection
w~ll to the EPAC site when process problems at the well caused a bottleneck.
Therefore, both injection-well waste records and EPAC records were included
in summarizing wastes possibly present at the site.
In the summer of 1978, a truck driver died at the site. The coroner's
report stated the likely cause of death as hydrogen sulfide inhalation.
Apparently the liquid wastes he was unloading were incompatible with
wastes in the receiving pond, thus creating hydrogen sulfide gas. State
and Federal regulatory officials inspected the site following the above
incident. The investigation revealed the presence of large open, unpermitted
ponds containing unknown materials. As a result of the governmental
investigation, the 18th Judicial District Court ordered the closure of
the site to eliminate all health hazards.
Closure activities began in September 1978, and were overseen by the
State. Closure activities consisted of the following:
1.
Dewatering by spr~y evaporation
2. Transfer of residues from Ponds 1 through ~ to Pond 4 (LDEO officials
report that this activity may have been a partial removal only).
3.
Filling in the ponds with native soils and an admixture to Pond 4.
Contouring the filled ponds.
4.
During the transfer of material to Pond 4 from Ponds 1-3, there may have
been some spill-over of material to the periphery of Pond 4. Closure
activities were completed in the spring of 1979, and the site was placed
on inactive status by EPA later that year. The quantity of wastes remaining
on site was estimated to be 1 million cubic feet (36,400 cubic yards) (RI
report) .
After closure, the State received complaints about odor and surface
contamination in the swamp south of the site. The State contracted
Resource Technology, Inc. in 1981 for a preliminary site investigation,
and a further investigation by Woodward-Clyde Consultants was completed
in 1982. These studies included installation of a total of 12 groundwater
monitoring wells, although only three of these were sampled. Groundwater
data were inconclusivp.. Some evidence of surface pesticide contamination
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I'
3
Based on the information obtained during these site investigations, the
Bayou Sorrel Site was added to the National Priority List of Superfund
sites on December 20, 1982. The listing action provided the mechanism
for the Environmental Protection Agency (EPA) to perform a Remedial
Investigation (RI) to determine the nature and extent of wastes at the
site.
The final Remedial Investigation Report was completed in December 1985,
and the Feasibility Study Report completed in February 1986.
Current" S'te" Status
The Remedial Investigation (RI) field activities at the Bayou Sorrel site
were conducted in two phases. Phase I activities from March to May 1984
inc1uded co11ecting groundwater, surface water, sediment, soil, and
biological samples. Phase II activities were conducted in March 1985 and
consisted of resamp1ing of onsite monitoring wells. .
The results of the RI along with reviews of site operating records, State
files and Potentially Responsible Parties (PRP) 104(e) responses
allowed the' site to be characterized in terms of:
- Wastes present
- magnitude and extent of contamination;
- rate and direction of waste migration;
- target receptors including population at risk, threatened
resources, and sensitive ecosystems;
- site geology, and
- site surface water and ground water hydrology.
The following is a summary of the site investigation. The top stratum of
the site is approximately 70 feet thick and consist mainly of silts and
clays with hydraulic conductivity ranging from 10-ato 10-4 cm/sec. One
lenticular silt sand bed has been identified within the top stratum with
hydraulic conductivity ranging from 10-5 to 10-3 cm/sec.
Beneath the top stratum are thick deposits of sand, gravel, and silt
which may extend to 700 feet below land surface. These coarser sediments
comprise the only regional aquifer in the parish and are referred to as
the Plaquemine aquifer. Groundwater withdrawals from the Plaquemine
aquifer in the vicinity of the site are minimal due to the low population
density and marginal. groundwater quality. The Office of Public Works of
the Department of the State of Louisiana maintains a computer file of
water wells in the area including those wells on file by the U. S.
Geological Survey. This inventory shows no wells within two miles of the
waste site. ERM-Southwest (1984) conducted a field survey of water wells
and located two wells within a two-mile radius of the site. These wells
were used at local fishing camps for washing only and not for potable
supply. Water sample analyses from these two wells exhibited poor water
quality with TDS of about 2,000 mg/1, most of which was dissolved chlorides
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4
The Plaquemine aquifer is hydraulically connected to the main channel of
the Mississippi River which cuts through the confining top stratum.
Stage fluctuation in the river controls head distributions and consequently
flow direction in the aquifer. During most of the year, heads in the
aquifer are above land surface in the vicinity of the site.
The primary surface water features in the area include the following:
- The Upper Grand River which borders the Bayou Sorrel Site on the north
and flows to the west and empties into an unnamed borrow river which
flows to the south. The borrow river borders the site on the west.
- Pat Bayou borders the Bayou Sorrel site on the east and drains in a
southerly direction into Pat Bayou.
- The southern portion of the site is bordered by back water swamp which
covers portions of the site much of the year.
- There are an unnamed borrow lake (approximately 50 acres) and pond
(approximately 1 acre) located on the northern portion of the site.
None of these features appear to have been impacted by the Bayou Sorrel
site. Runoff generally flows to the south and east, mostly to Pat Bayou
and from there to Pat Bay. Most of the site would be inundated by the 100
year flood caused by backwater from the Borrow River and Upper Grand River.
To evaluate the nature and distribution of waste at the site~ soil and
core samples, groundwater samples, surface water samples, sediment samples,
and biological samples were collected for laboratory analyses. Based on
104(e} responses and other site records, wastes disposed at the site
during its active life were of the following types:
o
Process wastes from pesticide/herbicide manufacture; these include
distillation residues, contaminated packaging, and miscellaneous
wastes;
o Sulfide-containing wastes (scrubber blowdown and spent caustic) from
hydrocarbon processing and exploration activity;
o Spent wash solutions from boiler-cleaning and process equipment-cleaning
contractors.
The relative quantities of wastes disposed of at the site is unknown, but
the total quantity was estimated to be approximately 1,000,000 ft3 from
Louisiana Department of Natural Resources files.
Some localized surface soil contamination has been found at the site,
especially at the south end of the site. This contamination includes
herbicide and other organic compounds. Some waste materials, including
some which may liberate hydrogen sulfide gas, were found under a thin
layer of soil outside of the capped area over pond number 4. Similar
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5
During the 1978-79 closure activities the volume of on-site ponds was
reduced by enchanced evaporation and landfarming of the pond supernatant.
The remaining contents were then solidified with soil and other additives,
and the ponds were covered with on-site soil. Because of these closure
techniques, there is estimated to be close to 1,000,000 yd3 of contaminated
soil and waste at the site.
So~e inconsistent data indicate the possibility of organic contamination
of shallow groundwater but at very low levels. No organic constituents
were noted in GC/MS analyses of samples from the Plaquemine aquifer
beneath the site, except for a single unknown compound at 12ppb from a
sample from well 11-D. Contamination of this aquifer by the site appears
very unlikely due to the upward hydraulic gradient.
Organic compounds were reported from seven onsite shallow wells for
compounds not readily explainable as being derived from laboratory
contamination or well construction materials. All of the reported
compounds are either reported at very low ppb levels, were present in
laboratory blanks at low levels, and/or were not detected in duplicate
samples or analyses by ERM-Southwest.
In a study completed in November 1984, by the Bayou Sorrel Task Force
(BSTF), 30 buildings were located within two miles ~f the site. Only
three of these buildings were found to be year-round residences. Most
buildings in the area are hunting or fishing camps. The closest community
to the site is the town of Bayou.Sorrel, approximately six mile$.southeast
of the site.
The population potentially at risk is:
- Hunters or fishermen at or near the site.
- Petrochemical workers using the site to gain access to their wells.
Enforcement
State and Federal regulatory officials inspected the Bayou Sorrel site
following the death of a truck driver at the site in the summer of 1978.
The inspection revealed the presence of large, open, unpermitted ponds
containing unknown materials.
As a result of the governmental investigation, the 18th Judicial District
Court ordered the closure of the site to eliminate all health hazards.
In the fall of 1982, EPA identified approximately 20 Potentially
Responsible Parties (PRPs) for the Bayou Sorrel site. T~ese 20 PRPs were
notified of their potential liability and offered the opportunity to
participate in remedial activities. In the spring of 1983, approximately
70 additional PRPs were identified and also sent notice letters. None of
the PRPs would agree to conduct the necessary studies and implement the
resultant remedial activities that were identified by these studies. A group
of PRPs did, however, offer to conduct the Remedial Investigation and
FeasibilHy Study (RIIFS) at the site but would not agree "up-front" to
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6
Independent of the EPA investigation, representatives of the PRPs began
remedial investigation activities in October 1983. The PRP activities
are described in other reports. To the extent possible, the EPA activi-
ties were coordinated with those of the PRP's to minimize duplication of
effort.
A FS completed by the Bayou Sorrel Task Force in February 1985, recommended
a -remedy similar to EPA's clay cap alternative, which the PRPs offered to
implement.
Alternatives Evaluation
Site specific remedial objectives were established prior to the collection
of RI data for the receptor media indentified at the site. The FS
developed by CH2M Hill and SRW Inc. developed these objectives which
follow:
- Minimize the threat to public health, if any, from use of or contact
with onsite surface water bodies which include the lake and small
pond, as well as the back swamp in the wet season. Protect the
environmental quality of these water bodies from degradation due to
. contaminants.
- Minimize the threat to public health from use of or contact with off-
site surface wateT bodies which include the back .swamp, the Upper
Grand River, Grand River, Pat Bay, and Pat Bayou, and protect the
environmental quality of these water bodies from degradation due to
contaminants.
- Minimize the threat to public health from direct use of the shallow
groundwater and protect the quality of the Plaquemine Aquifer and
surface water bodies which might receive discharges from the shallow
groundwater.
- Minimize adverse effects of present and potential users of the
Plaquemine Aquifer from contaminants migrating from the site.
- Isolate contaminated materials from direct contact with surface
50115 and sed1ments to min1mize migration of contamination.
- Limit the potential for air releases from the site which would have
adverse effects on human health and limit onsite concentrations of
hydrogen sulfide, cyanide, and other hazardous air pollutants to
within OSHA standards.
Based on the data collected to date, active remediation will not be
required to meet all of the objectives. The objectives serve as the
basis for the environmental assessment in the remedial alternatives
evaluation. By combining the applicable remedial action technologies and
considering the pathways of migration in accordance with 40 CFR 300.68(f),
13 remedial alternatives were developed for the Bayou Sorrel Site. Table
1 lists the alternatives, along with the technologies they include, and
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7
The remedial action alternatives developed included the follJwing
categories:
- No Action/Limited Action Alternatives
- Alternatives that Meet the Objectives of CERCLA
. - Alternatives that Exceed All Applicable Standards
- Alternatives that Meet All Applicable Standards
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8
TABLE 1
BAYOU SORREL SITE
LIST OF REMEDIAL ALTERNATIVES DEVELOPED FOR SCREENING
Pathway of
. , 'Cohtami "aht . Hi grist ion' , .
Soil/Sediment Shallow
A lternati ve .: . Oeser; pt; Oh' , . , . . . . . ilaste' . . . . . , . Grouhdwater' ., Remedial' Techno' ogH~s' the' lice,!' . .;,
1
2
No Action
Umited Action
N/A
X
N/A
None
Regrading, topsoil, seeding, offsite
disposal of surface waste, fencing,
burrowing animal control, groundwater
monitoring, construction of diversion
roadway to direct traffic around dis-
posal areas.
3
Clay Cap (Ons i te
Materials)
x
Regrading, cap, gas venting, topsoil,
seeding, offsite/onsite disposal of
surface waste, onsite disposal of
contaminated soils, fencing, burrowing
animal control, groundwater monitoring
construction of diversion roadway to
direct traffic around disposal areas.
Regrading, cap, gas venting, topso
seeding, offsite/onsite disposal of
surface waste, ons1te disposal of
contaminated soils, fencing, burrowing
animal control, groundwater monitoring
construction of diversion roadway to
direct traffic around disposal areas.
4
Clay Cap (Offsite
Materials)
x
5
Geomembrane Cap
x
x
Regrading, cap, synthetic membrane,
drainage layer, gas venting, topsoil,
seeding, offsite/onsite disposal of
surface waste, onsite disposal of
contaminated s011s, fencing, burrowing
animal control, groundwater monitoring
construction of diversion roadway to
direct traffic around disposal areas.
6
. Geomembrane Cap
with Slurry Wall
x
x
Slurry wall, regrading, pressure
relief trench, seepage collection sys-
te~, off-site disposal of seepage,
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Table 1
(cont'd)
9
Pathway of
.,' Contamihant Mifiration"
SOll/Sedlment Sallow
. ". '" 'Waste'" "', . Groundwate'r'" Remeaial' Technologies
terhatiVe' ... Description
7
8
9
10
11
12
13
1hcliJoed' , .
Offsite Material
Cap with Slurry
Wall'
layer, gas venting, topsoil, seeding,
offsite/onsite disposal of surface
waste, onsite disposal of contaminatec
soils, fencing, burrowing animal con-
trol, groundwater monitoring, con-
struction of diversion roadway to
direct .traffic around disposal areas.
Slurry wall, regrading, pressure re-
lief trench, seepage collection
system, off-site disposal of seepage,
cap, gas venting, topsoil, seeding,
offsite/onsite disposal of surface
waste, onsite disposal of contaminatec
soils, fencing, burrowing animal
control, groundwater monitoring. con-
struction of diversion roadway to
direct traffic around disposal 'areas.
x
Ons ite RCRA
Landf; 11
x
x
Waste removal, fill placement. m~mbrar
liner, leachate collection/detection
system, cap, gas venting, topsoil,
seeding, groundwater monitoring.
Waste removal, haul to existing per~
mitted offsite disposal facility,
backfill, top soil, seeding, ground-
water monitoring, slurry wall,
injection well disposal.
Offsite RCRA
Landfi 11
x
x
Onsite Inci ner-
ation
x
Waste removal, incineration, backfill,
topsoil, seeding, groundwater
monitoring, slurry wall, injection
we 11 di sposa 1.
x
Offsite Inciner-
ation
x
x
Waste removal, haul to existing per-
mitted incinerator, backfill, topsoil,
seeding, groundwater monitoring,
slurry wall, injection well disposal.
Waste removal, biological treatment of
waste, sl~dge disposal, topsoil, seed-
ing, groundwater monitoring, slurry
wall, injection well disposal.
Onsite Biotreat-
ment
x
Land Treatment
x
Waste removal, landfarming, backfill
with treated soils, topsoil, seeding,
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10
1NITIAL' ALTERNATIVE SCREENING
Each remedial action alternative developed was evaluated and screened in
accordance with the NCP 40 CFR 300.68 (g) and (h). The initial screening
was based on the following criteria:
EffeCt; vehess
Each alternative was evaluated for its effectiveness in protecting public
health, welfare and the environment.
Eng1heering' Feasibility
Each alternative was evaluated in terms of the site specific waste
characteristics and the feasibility of the alternative to mitigate the
site specific problems. '
Cost
Comparative cost estimates were prepared to assess the relative order-
of-magnitude cost for each of the remedial alternatives.
Based on the initial screening of alternatives, the following alternatives
were retainea for detailed evaluation in accordance with the NCP, 40 CFR
300.68 (h).
- No Act ion,
- Clay cap with onsite materials
- Geomembrane cap
- Geomembrane cap with slurry wall
- Source Removal with onsite inc,ineration
- Source Removal with offsite disposal in
a secure landfill
In addition to their alternatives listed above, the alternative recommended
by ERM Southwest in the FS Report prepared for the BSTF was evaluated in
detai 1.
Following the establishment of remedial objectives and development of
general response actions to meet the objectives, remedial action technologies
were developed within the general response actions. The general response
actions and associated remedial technologies were evaluated primarily for
technical feasibility relative to site characteristics, applicability, and
also for the following criteria: .,
- Environmental
- Public health
- Institutional
- Cost
criteri a
Table 2 lists the general response actions considered and the associated
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11
TABLE 2
BAYOU SORREL SITE
GENERAL RESPONSE ACTIONS AND ASSOCIATED REMEDIAL TECHNOLOGIES
Response Action
No Action
Technologies
None
Limitea Action
Some monitoring and regrading
Containment
Capping; groundwater containment barrier walls;
bulkheads; gas barriers
Groundwater pumping; liquid removal; dredging
Pumping
Collection
Sedimentation basins; French drain; gas vents;
gas collection system
Diversion
Grading; dikes and berms; stream diversion
ditches; trenches; terraces and benches; chutes
and downpipes; levees; seepage basins
Complete Removal
Drum grappling; excavation of soils, sediments
and buried waste, pumping of surface wa~er,
removal of waste transport pipes
Partial Removal
Drum grappling; excavation of soils and sediments;
removal of waste transport pipes
Incineration; solidification; land treatment;
biological, chemical, and physical treatment
Onsite Treatment
Offsite Treatment
Incineration; biological, chemical, and physical
treatment
In-Situ Treatment
Permeable treatment beds; bioreclamation; soil
flushing; neutralization; landfarming
Temporary storage structures
Storage
Onsite Disposal
Landfills; land application
Landfills; surface impoundments; land application;
deep well injection 0"
Offsite Disposal
Alternative Water
Supply
Relocation
Cisterns; above-ground tanks; municipal water
system; individual treatment devices
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12
TABLE 3
BAYOU SORREL SITE
APPLICABLE REMEDIAL ACTION TECHNOLOGIES
Genera 1
Response" ,. . .".. Techno10gy"
" . . . , . .". ' . " ; ~ . ~ ,
.. .' " . , . ,'. ,. ( ,. . t , . .", . . .,
1. No Action
None
Moni tori n9 '
2. Containment
CAPPING:
Onsite Clay
Offs i te Clay
Synthetic Membrane
Multilayered System
GROUNDWATER BARRIERS:
Circumferential Placement of Soil-Bentonite Slurry Wall
Cement-Bentonite Slurry Wall
GAS BARRIERS:
Synthetic (See Collection)
3. Pumpi n9
GROUNDWATER PUMPING:
None
LIQUID REMOVAL:
None
DREDGING:
None
4. Collection
SURFACE WATER:
Seepage Bas ins
Sedimentation Basins
SUBSURFACE DRAINS:
French Drains
Dual Media Drains
GAS:
Passive Pipe Vents
Passive Trench Vents
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General
Response' . . . , . ,
5. Diversion
6. Complete Removal
7. Partial Removal
13
. . TechnologY'
GRADING
. . .. , . . . ., . ( , t' . , . . . I, ~ . . ..
R EVE GET A TI ON:
Grasses
Certain Legume Species
SURFACE WATER:
Di kes and Be rms
Ditches, Trenches and Diversions
Seepage Basins
Sedimentation Basins
Levees
Floodwall
ALL CONTAMINATION:
Dragline
Backhoe
Industrial Vacuum
Drum Grappler
AREA OR CONCENTRATIONS
8. Onsite and Offsite Treatment
INCINERATION:
Rotary Kil n
SOLIDIFICATION
Lime Based
LAND APPLICATION
BIOLOGICAL TREATMENT:
Activated Sludge
Trickling Filters
Powdered Activated Carbon
CHEMICAL TREATMENT:
Neutralization
Precipitation
Carbon Adsorption
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14
Genera 1
Response"'<" 'Technology'"
PHYSICAL TREATMENT:
Flow Equalization
Flocculation and Sedimentation
Oil/Water Separator
Air Stripping
Steam St ri ppi ng
Filtration
Sludge Dewatering
Removal
. '; '. ,".
. I. " -. ," .
; . '.. . ',' . . . . . '. ( , , .. '"'. .
9. In-Situ Treatment
CONTAMINATED MATERIALS:
Bioreclamation
Permeable Treatment Beds
10. Storage
Temporary
11. Onsite Disposal
Landfill
12. Offsite Disposal
Landf; 11
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15
Data collected during the RI were evaluated with respect to each techno-
logy to evaluate its site specific applicability. This evaluation was
based on:
- Site geology, hydrogeology, and soils
- Waste characteristics (compatibility, ignitability, associated
hazard)
- Technology performance and reliability
- Technology implementability (construction, operation and maintenance)
Site applicable remedial action technologies which survived the technology
screening are listed in Table 3.
The applicable technoloyies were combined into comprehensive remedial
action alternatives that will mitigate the threat to human health and
environment posed by the site. The formulation and refinement of the
remedial action alternatives follows the requirements of the NCP as set
forth in 40 CF~ 300.68 (f). Each alternative consists of one or more
remedial activities which focus on achieving the remedial action objectives
for the site.
As discussed earlier the objective of the remedial action alternatives at
~he Bayou Sorrel Site is to prevent or minimize the migration of contaminants
from onsite sources and to prevent direct contact with the contaminated
media. This objective addresses the following site-specific problems:
- Contaminated surface soils
- Shallow groundwater-possible present or future contamination
- Seeps in the existing cap area
- Waste outside the cap areas
- Cap erosion and inadequate cover
- Seasonal flooding of the area
Inadequate site restriction
The methodology used to develop the remedial action alternatives for the
Bayou Sorrel Site follows the structure presented in uGui.dance on
Feasibility Studies Under CERCLA,II in accordance with the NCP. The steps
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16
Id~htify' S't~' Proble~s - The site proble~s and contamination exposure
pathways are identified in the Endangerment Assessment (EA) and the
Remedial Investigation (RI) reports.
2. 1ijehtifyGen~~~' Response' AttiohS - Based on the information collected
in the ~l and the problems defined, general classes of response
actions are identified. The response actions address the site
problems and the cleanup goals and objectives.
1.
3. 1dent1fy an~ Screen' Technolb~ - Applicable technologies for each
general response action are ldentified in the FS report. The site
data is reviewed to aid in the identification of compatible technologies
that are effective in mitigating the site-specific and waste-specific
problems. The screening criteria for the technologies included
environmental and public health effects, site-related considerations,
and cost. Those technologies deemed incompatible, technically
inappropriate, or cost prohibitive were eliminated from further
consideration.
4. Develop' Alternatives bY' Combining' Techno'o~ - The technologies
which pass the screening process are assemb ed into alternatives
which address the pathways of migration in accordance with 40 CFR
300.68 (d). The technologies are combined into alternatives based on
acceptable engineering practice and project remediation goals. In
accordance with 40 CFR 300.68 (f), the most applicable tech"ologies
are assemblea into comprehensive remedial action alternatives for the
site. This involves selecting remedial action for each pathway of
migration and integrating them so that at least one remedial action
alternative is developed for each of the following five categories:
a.
No Action;
b.
Offsite storage, destruction, treatment or secure disposal of hazardous
substances at a facility approved under RCRA and all other applicable
USEPA, State, and local standards;
c. Onsite remediation that attains all applicable or relevant Federal,
State or local public health or environmental regulations, standards,
guidelines and advisories;
d.
Remediation that exceeds all applicable or relevant Federal, State,
or local public health and environmental raegulations, standards,
guidelines, and advisories; and
e.
Remediation that meets CERCLA goals of preventing or minimizing
present or future migration of hazardous substances and protects
human health and the environment, without necessarily complying with
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17
The thirteen remedial alternatives that were developed for the Bayou
Sorrel site were evaluated and screened in accordance with the NCP
[40 CFR 300.68 (g) and (h)]. The initial screening was based on:
- The Effectiveness of the alternative in protecting public
welfare and the environment;
- the engineering feasibility of the alternative, and
- cost of the alternative.
health,
The alternatives which passed the initial screening were refined and
developed in detail for costing purposes pursuant to the NCP [40 CFR
300.68 (h) (2) (i)]. The following criteria were utilized to technically
evaluate each alternative.
- Performance
- Reliability
- Engineering Implementability/Constructability
Public Health and Welfare
- Environmental Impacts
Institutional Factors
Costs
A description of the detailed evaluation screening criteria follows:
Perfo'rmance
The performance criterion evaluates the alternatives in terms of their
effectiveness and useful life. Effectiveness relates to how well the
alternative meets the objectives of ultimate remediation to prevent or
minimize release of contamination. Useful life relates' to the period of
time that the effectiveness can be maintained.
Rel hM 1 ity
The reliability of an alternative is assessed on the basis of operation
and maintenance and demonstrated performance. Operation and maintenance
considerations include labor availability, frequency, necessity, and
complexity. Demonstrated performance is characterized by proven field
performance, low probability of failure, and proven pilot scale testing.
Eng1 nee"; n~f' tmp1 i!mentab1' 1ty'lCohsthJehM 1 1 ty
The engineering implementability of each alternative is assessed based on
ease of installation, time to implement the alternative, and time to
achieve the benefits of the alternative. Constructability refers to the
applicability of the alternative to site conditions, external conditions
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18
availability. Time to implement includes time for treatability studies,
design, and construction. Beneficial results are defined as a reduction
of contamination or degree of exposure necessary to obtain remediation
goals.
Public Health and Welfare
The public health and welfare criterion evaluates the safety of each
alternative during construction and operation and upon failure. The
evaluation covers safety of community, environment and workers during
installation and operation. It also considers effects in the event of
failure after remedial action ;mplementation.
Environmental Impacts
The environmental impact criteria are evaluated in terms of short-term and
long-term effects. The short-term effects are generally construction-
related and refer to site pollution, site alteration, and construction
debris. Site pollution refers to odor, noise, air emissions, surface
water and/or groundwater contamination caused by construction activities.
Site alterations relate to wildlife habitat alteration, historic site
alteration, and disruption of households, businesses and services. T~e
construction debris evaluation considers the amount and type of debris
and requirements for "disposal.
The long-term impacts are also evaluated for site pollution and site
alteration. The site pollution criteria consider the odor, noise, air
pollution, surface and/or groundwater contamination after remedial action
implementation. Long-term site alteration considers wildlife habitat
alteration, threatened and endangered species, use of natural resources,
parks, transportation, and urban facilities; historic site alteration;
relocation of households, businesses, and services; and aesthetic changes.
Institutional Factors
The institutional evaluation considers political jurisdictions, land
acquisition, and land use and zoning. Alternatives are evaluated 1n
terms of ease of satisfying applicable institutional criteria. In
accordance with the NCP [40 CFR 300.68 (h) (2) (ii)], alternatives which
pass initial screening must be technically and economically evaluated
to develop the most cost-effective remedial alternative. To perform a
detailed cost analysis, the various major components of each alternative
must be evaluated and estimates of expenditures required_to complete each
measure developed in terms of capital and operation and maintenance costs.
An indepth discussion of the evaluaton pror.ess can be found in Section 5
and .Appendix C of the FS report. Table 5 provides information on
capital costs and present worth of the remedial alternatives for thp.
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19
Consistency with'other Environmental laws
In accordance with 40 CFR 300.68 (f), the most applicable technologies
are assembled into comprehensive remedial action alternatives for the
site. This involves selecting remedial actions for each pathway of
migration and integrating them so that at least one remedial action
alternative is developed for each of the five categories:
a.' No Action;
b. Offsite storage, destruction, treatment or secure disposal of hazardous
substances at a facility approved under RCRA and all other applicable
USEPA, State, and local standards;
c.
Onsite remediation that attains all applicable or relevant Federal,
State or local public health or environmental reagulations, standards,
guidelines and advisories;
d. Remediation that exceeds all applicable or relevant Fedral, State, or
local public health and environmental regulations, standards, guide-
lines, and advisories; and
e.
Remediation that meets CERClA goals of preventing or minimizing present
or future migration of hdzardous substances and protects human health
and the environment, without necessarily complying with other
environmental and/or public health regulations.
Within each category, remedial actions are developed which are cost
effective, and have relatively high technical and public health and
environmental value in comparison to other combinations of retained
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20
TABLE 5
Capital Cost and Present Worth
for Remedial Alternatives
Bayou Sorrel Site
Capital Cost** Present Worth
Remedh" A 1 ternat iVe ' . , , '. . . , , , I . . . " , . , U' ,.,,, 11 bn)' . . ' .. , ; .' . . {S' ""111 on')'
A. No Action 0
B' . Clay Ca p
15.3
16.7
21.3
22.2
B2. Geomembrane Cap
C. Geomembrane Cap with
Slurry Wall
23.2
28.7
D. Onsite Incineration
- 10 Year Term
- 30 Yea r Term
82.9 486.0
36.2 214.4
556.5 561.6
16.'6 22.7
E. Offsite Disposal
F. Recommended Alternative.
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21
The main environr.ental law pertaining to this site is RCRA. Four of the
alternatives developed for the Bayou Sorrel site would comply with RCRA.
These are:
- Geomembrane Cap
- Geomembrane Cap with Slurry Wall
-. Offsite RCRA Landfill, and
- On-site incinerator
For any alternative requiring off-site treatment or disposal, a facility in
compliance with all applicable laws would be utilized. This would include
such things as contaminated storm water or pore water to an injection well
(UIC), excavated drums to a landfill (RCRA), etc.
The following elements are common to the three on-site alternatives
developed in the FS.
o Regrading site to control runoff, limit cap erosion, limit surface water
ponding and divert storm water from waste areas.
o Insta11ation of a geofabric and sand drainage layer and collection
system. A two percent crown would be established over the drainage
layer using onsite unclassified soils. A clay cap constructed of
onsite clayey soils would be placed over. the unclassified soils in the
crowned areas.
. .
Construction of the cap would involve the placement and compaction of
about 24 inches of clay, maintaining the minimum 2 percent grade. The
cap would be graded so that it would be crowned at the center and
sloped to drain toward the perimeter at a minimum gradient of about
2 percent. This grade would maintain surface drainage to the cap
perimeter while also allowing for settlement due to the compression of
the underlying waste and soils. Providing a 2 percent gradient on the
surface should increase the runoff coefficient, resulting in a reduced
contact time and decreased infiltration.
o A 6-inch thick sand layer would be constructed on the surface of the
compacted clay to allow for drainage of the topsoil. This layer would
be drained by extending sand drainage channels beyond the capped areas.
o A geotextile filter layer would be installed over the drainage
layer to prevent the drainage layer from becoming clogged with
fines washed down from the topsoil.
o A system of pipes, manholes, pumps and ponds would be installed to
co11ect and store the seepage from the lower drainage layer.
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23
Elements common to both excavation alternatives evaluated by EPA are as
follows:
o A road berm would be constructed to elevation 10 to prevent flooding
of the waste areas during excavation operations. A cement/ bentonite
slurry wall would be installed to an elevation approximately 5 feet
below the waste to be excavated. The purpose of this slurry wall
. would be to promote stability of the hole and to minimize inflow
of groundwater during excavation.
o A temporary waste storage/dewatering pad would be constructed, with a
synthetic membrane over a graded onsite surface. The membrane would
be covered with a minimum of 18 inches of sand and gravel which would
serve as a leachate collection system. Sides of the membrane would
be raised at the pad's perimeter to contain leachate.
o A system of pipes, pumps, and ponds would be installed to collect and
store the drainage from the excavation and the storage/dewatering pad.
The contaminated water collection ponds would be situated south of the
waste excavation areas. These ponds have been sized to contain the
surface runoff from the site area during a 10 year, 6 hour design
storm. The pond south of the landfill cells and Ponds 1 to 3 would
contain about 4.5 million gallons of runoff and the pond south of.
Pond 4 would contain about 2 million gallons. The liquids collected
would be transported and disposed of in a permitted injection well.
o Excavation.of waste and contaminated soils would be performed within
the limits of the slurry wall. A bench would be left adjacent to the
slurry wall on the inside of the excavation for structural support.
Two to one side slopes would be retained below the bench to provide
adequate stability against a slope failure into the excavation.
Excavated waste would be placed on the storage pad for dewatering.
In addition to these elements, the offsite disposal and on-site incineration
alternatives have elements unique to each alternative.
Sourc~' Remova1'w1th"Offs1te' D1s~
o The surface of the former waste disposal areas would be regraded to
control runoff, limit cap erosion, limit surface water ponding, and
divert storm water from the waste disposal areas.
o A system of pipes, pumps, and ponds would be installed to collect and
store the drainage from the excavation.
o The excavated wastes would be tranported to an offsite permitted RCRA
compliant secure facility for ultimate disposal by landfilling.
Treatment of the wastes with a 10 percent mixture of lime, kiln dust,
or similar material, may be necessary for proper material handling and
stability, to facilitate transportation and disposal operations, and
to comply with restrictions against land disposal of wastes containing
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o
22
o During installation of the clay cap, a gas venting would be installed
to reduce the buildup of system methane aITd other gases beneath the
cap. The vented gases would be treated by installation of carbon
canisters and periodic air sampling would be performed to evaluate the
need for continued or additional treatment.
o The capped areas would be covered with 12-18 in. of topsoil from a suitable
. onsite borrow area, and seeded to reduce erosion. Installation of non-
woven fabric mat may be used in certain areas to reduce the erosion
potential prior to establishment of vegetation.
o All miscellaneous wastes outside the capped area, i.e. waste transport
pipes, waste storage drums from the RI, etc. would be collected and
either hauled offsite to a permitted landfill or placed under the
capped area, along with any contaminated soils or waste identified
during the remediation.
o All regraded areas would be surrounded with a 6-foot high chain link
fence to restrict disposal area access.
o Groundwater monitoring of the shallow and deep aquifers would be
performed on a semi-annual basis for a period of at least 30 years.
The monitoring system will be based on existing site data and current
RCRA guidance. The groundwater would be monitored for contaminants
previously identitied at the site and contaminants expected as a
result of the materials disposed of at the site.
o Gravel access roads would be constructed completely around all fenced
areas to allow continued recreational use of the adjacent lands and
Borrow Lake while diverting the traffic around and away from the
disposal areas themselves.
The geomembrane cap alternative, in addition to the items listed above,
would include a minimum 30 mil thick HOPE geomembrane over the clay
layer of the cap.
The geomembrane cap with slurry wall alternative consists of the measures
described for the geomembrane cap alternative with the addition of a
slurry wall around the capped areas. This alternative also includes a
pressure relief drain system inside the slurry wall to provide an outlet
for increased pore water pressure caused by settlement of the cap or
seasonal groundwater elevation changes. A system is also included to
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24
o Upon completion of the excavation in one area, the excavation would be
dewatered and backfilled with soil borrowed on site. The backfill
would be properly placed and compacted to provide a stable, uniformly
graded surface.
o Upon completion of the backfilling operations, the surface would be
graded, a seed bed prepared, and appropriate seed sown.
o . A short-term monitoring program of the shallow groundwater should be
performed on a semi-annual basis for a period of three years. Wells
would be installed at the former disposal areas to monitor the per-
formance of source removal.
The following elements are unique to the on-site incineration alternative:
o Wastes would be allowed to dewater on a covered storage pad area, prior
to incineration.
o The wastes would be transported to feed hoppers for the onsite
incinerator and then burned. The onsite incinerator would be covered
to facilitate continuous operation even during the rainy season. The
ash would be cooled and disposed of in a state permitted solid waste
facility. Cooling of the ash would be accomplished with a Tube Cooler,
whi ch is a water-based heat exchanger whi ch proh; bits, contact of the
water with the ash. The water would be cooled using a cooling tower
and clarified prior to re-use in a concrete lined settling basin.
Because of the nature of the onsite wastes no significant reduction in
total volume is anticipated.
o As the process of excavation continued, the excavation would be back-
filled with onsite soils borrowed from adjacent areas. The backfill
would be properly placed and compacted to provide a stable, uniformly
graded top surface. Careful handling of the staged excavation and
, backfilling process would be required to prevent re-contaminating the
backfilled soils. In addition, a sump would be required at an elevation
lower than the backfilled area to prevent saturating the soils with
contaminated water. The actual sequence and sizing of these operations
and facilities would be performed during the design phase.
o Upon completion of the backfilling operations, the surface would bp.
graded, a seed bed prepared, and appropriate seed sown.
o A short-term program of monitoring the shallow groundwater would be
performed on a semi-annual basis for an anticipated period of three
years. Wells would be installed at each of the disposal areas to moni-
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25
Recommended Alternative
40 eFR 300.68 (J) (NCP) States:
"The appropriate extent of remedy shall be determined by the lead agency's
selection of the remedial alternative which the agency determines is cost
effective (i.e. the .lowest cost alternative that is technologically feasible
and reliable and which effectively mitigates and minimizes damage to and
provides adequate protection of public health, welfare. or the environment)".
In addition, EPA policy requires that, as a general rule, a selected
alternative remedy attain applicable or relevant standards, with certain
exceptions, including interim remedies. Based upon the evaluation of the
RIFS, EPA has determined that onsite disposal with a geomembrane cap and a
slurry wall around the old landfill areas and pond 4 meets the NCP criteria
found at 4U CFR 300.68. This will be the minimum remedy that EPA would
accept following negotiations with Responsible Parties for the Bayou
Sorrel site.
As discussed in the RI and FS, direct use of shallow groundwater in the
area is not documented and contamination of shallow groundwater has
possibly occurred but at low levels «100 ppb) and does not appear to be
wide spread. Also, the deeper (Plaquemine) aquifer is under free-flowing
art~sian condition which results in an upward hydraulic gradient (and
resulting upward flow) through overlying soils. Therefore, contaminant
transport will be limited to diffusion, which is generally very slow.
To ensure that contaminants are not leaving the former waste disposal
areas via the shallow groundwater and to ensure that the Plaquemine
aquifer-Qoes not become contaminanted, a comprehensive groundwater
monitoring program will be conducted. A "trigger" mechanism will be
included so that additional remedial actions will be taken if it becomes
necessary.
At a minimum, monitoring will continue for 30 years and a decision on the
necessity for continued monitoring will be made prior to the end of the
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26
Compliance with Section 121 of the Superfund Amendments and Reauthorization
Act of 1986
Under ~121 (b)(I) "remedial actions in which treatment which permanently
and significantly reduces the volume toxicity, or mobility of the hazardous
substances, pollutants, and contaminants is a principle element, are to be
preferred over remedial actions not involving such treatment".
RODs signed within 30 days of enactment of SARA must comply to the maximum
extent practicable with ~121 of CERCLA (~121(g)).
The selected remedy for the Bayou Sorrel site includes a RCRA compliant
cap, slurry walls around the most contaminated disposal areas, and
extensive groundwater monitoring (described in the next section). In the
process of selecting the remedial alternative, a number of remedies were
examined in accordance with the National Contingency Plan, 40 CFR 300.68,
and either screened or retained for final evaluation under 40 CFR 300.68(h).
Although the remedial alternatives were evaluated and a selection made
before the enactment of ~121 of CERCLA, the screened alternatives would
also not be appropriate under the requirements of the current law.
The following examines the rationale used in screening remedial alternatives
for the site under the NCP, 40 CFR 300.68, and whether this method resulted
in the selection of an appropriate remedy for meeting the intent of &121
of CERCLA to the maximum extent practicable. Those remedies which were
evaluated in accordance with the requirements of 40 CFR 300.68(g) "Initial
Screening of Alternatives", and are permanent remedies within the intent
of ~121 of CERCLA, or were ~etained and evaluated under 40 CFR 300.68(h)
, NDetailed Analysis'of Alternatives" are included.
Permanent remedies evaluated in the Feasibility Study which would comply
with the intent of ~121:
- tBiological Treatment
- tLand Treatment
- Offsite Incineration
- Onsite Incineration
Remedies which reduce mobility:
- Clay Cap
- Cap with Slurry Walls
Remedies Consistent with the NCP, but which do not comply with &121:
- Excavation and Off Site Disposal
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27
Source Removal with Onsite Biological Treatment
Source Removal with Onsite Land Treatment
These alternative were not retained after screening under 40 CFR 300.68(g).
However if effective, both would remove the organic constituents of the
waste onsite and so provide permanent remedies.
As viable treatment alternatives, biotreatment and landfarming have not
been shown to be effective treatment technologies for the wastes onsite,
the probability of failure of either remedy resulting from wastes not
amenable to such treatments is high. However, ~121(b)(2) states that
lithe President may select an alternative remedial action meeting the
objectives of this subsection whether or not such action has been achieved
in practice at any other facility or site that has similar characteristics."
A broad interpretation of this section may not allow the probability of
failure as sufficient reason for "initial screening" of the alternatives.
~121(b)(1)(D) requires that the remedy take into account "short and long
term potential for adverse health effects from human exposure." All of
the alternatives that provide source removal require the exvacation of
the wastes onsite. During treatment, excavation of the contaminated
soils would significantly increase the risks to public health from exposure,
and additionally increase the probability of a release from the site'.
The biotreatment and landfarming were estimated to require 40 years or .
more for completion. During these periods wastes would be excavated
significantly increasing the risk associated from the site. In light of
the risk of failure of these remedies and the greater risks both provide.
The promulgation of ~121 would not necessitate additional scrutiny of
these alternatives.
Excavation with Onsite or Offsite Incineration
These alternatives were not selected as the site remedy under 40 CFR
300.6~(i). Both would provide permanent remedies for the site.
Offsite incineration is comparable to onsite incineration, but would
create added risks of exposure while the wastes were being transported
and require an extended treatment period, approximately 80 years.
Onsite incineration is a proven technology which would permanently destroy
the organic constituents of the wastes and therefore reduce the toxicity
and mobility of the contaminants. The remaining ash would still have
considerable volume and may remain a hazardous waste since metals are
present onsite. Incineration of the million cubic yards'of wastes would
require from 10 years (6 incinerators) to 30 years (2 incinerators)
respectively. During this period there would be a significant increase
inpotential for adverse health effects from human exposure to the excavated
wastes and possible accidential disruption of the incineration leading to
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28
Incineration increases the risk of exposure to the wastes and to hazardous
emmissions for an extended period of time. Additionally, there is the
chance that after treatment a hazardous waste would still remain which
would require disposal. Incineration as a treatment alternative for this
site would not be a required alternative under ~121 of CERCLA.
Excavation and Offsite Disposal in a Permitted RCRA Facility
This alternative was not selected as the site remedy under 40 CFR 300.68(i).
Under ~121(b)(1), the offsite transport and disposal of hazardous materials
without permanent treatment technologies should be the least favorable
alternative remedial action where practicable treatment technologies are
available. This remedy is therefore unacceptable where other alternatives
are available.
RCRA Compliant Clay Cap
RCRA Compliant Clay Cap with Slurry Walls
A RCRA compliant cap and slurry walls with an extended monitoring program
was the selected remedy under 40 CFR 300.68(i). The contaminants will
remain onsite, and therefore under ~121(c) the remedy will have to be
reviewed "no less often than every 5 years after the initiation of such
remedial action to assure that human health and the environment are being
protected by the remdial action being implemented.
Wastes onsite were stabilized with cement kiln dust and lime, and mixed
with large volumes of soil. This decreased the mobility of the wastes and
reduced the relative toxicity from direct contact with them.
A cap would greatly reduce infiltration from rainwater preventing offsite
migration of the contamination. The addition of slurry walls would
isolate the wastes, further reducing the possibility of migration into
the offsite shallow groundwater. Extensive monitoring associated with
the selected remedy would illuminate problems enabling corrective action
to be taken expediently.
The remedial investigation for the site did not indicate offsite migration.
Endangerment is associated with th~potential for a release and direct
contact with the wastes. The soils underlying the site are extremely
impermeable. successfully limiting migration from the site with only the
current closure. Presently, as there is no detected offsite contamination,
no Louisiana Environmental Statutes are being violated. All applicable
or relevant and appropriate standard, requirement, criteria. or limitations
shall be complied with as required for a remedy in which .wastes remain
onsite under ~121(d).
Pe~anent remedies for the site were screened during the selection process
outlined in the NCP 40 CFR 300.68. However, since the permanent remedies
for the s;te do not meet the requriements of ~121(b), advent of the new
law does not necessitate reevaluating the remedy selection in order to
comply with the congres.sional intent of selecting permanent remedies when
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29
A capping remedy with slurry walls complies to the maximum extent
practicable witn 9121 of CERCLA and therefore is an appropriate remedy
for selection within the 30 day period following enactment of SARA as
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COMMUNITY RELATIONS RESPONSIVENESS SUMMARY
ON PREFERRED REMEDIAL ALTERNATIVE
BAYOU SORREL SITE, IBERVILLE PARISH, LOUISIANA
This community relations responsivenes summary is divided into the
following sections:
I. Overview - This section discusses EPA's preferred alternative
for remedial action. and likely public reaction to this alternative.
II.
III. Summary of Major Comments Received During the Public Comment
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I. OVERVIEW
In the presentation for the public meeting on February 26. 1986.
EPA discussed the remedial alternatives which were examined in
the Feasibility Study for addressing the contamination at the
Bayou Sorrel site.
After the initial screening of the alternatives. a detailed
evaluation was performed on the seven remaining. Except for
the no action alternative. all met basic criteria for protecting
public health and the environment and all had common components.
The alternatives are:
1. No Action
Est. Cost:
Est. Cost: S
S
Est. Cost: S
S
Est. Cost: S
S
- 0 -
2. Clay Cap
15.3 Million (capital)
21.1 Million (present worth)
16.7 Million (capital)
22.4 Million (present worth)
3. Clay Cap with Geomembrane
4. Geomembrane Cap with
Slurry Wall
23.2 Million (capital)
28.9 Million (present worth)
5. Source Removal with
Onsite Incineration
(IO-year timeframe)
Est. Cost: S 87.7 Million (capital)
$ 329.2 Million (present worth)
(30-year timeframe)
Est. Cost: S 37.9 Million (capital)
S 155.6 Million (present worthl
6.
Source Removal with
Offsite Disposal
Est. Cost:
S 536.2 Million (capital)
S 540.5 Million (present worth)
S 16.2 Million (capital)
S 21.5 Million (present worth)
7. Clay Cap with Deep
Leachate Collection
System
Est. Cost:
Based upon the evaluation of the Remedial Investigation and Feasibility
Study (RIfFS). the EPA has determined that onsite disposal with a geomembrane
cap and a slurry wall around the most contaminated areas is the corrective
action of choice. This remedy meets the NCP criteria found in 40 CFR 300.68.
and would be the minimum remedy that the EPA would accept following negotiations
with Responsible Parties for the Bayou Sorrel site. EPA anticipates that
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BACKGROUND ON COMMUNITY INVOLVEMENT AND CONCERNS
Site Background
The Bayou Sorrel site is approximately 20 miles southwest of Baton
Rouge, about 6 miles northwest of the town of Bayou Sorrel. The site
.is also known locally as "Grand River Pits," due to its proximity to
the Upper Grand River on the north. Fifty of the site's 265 acres
received wastes. Disposal areas consisted of four liquid waste ponds,
four landfills (at least one of which contains drums), and one land
farm. Data from water and sediment samples of a 50-acre lake and a
one-acre pond on the edge of the site indicate that they were probably
borrow pits and not used for disposal. Disposal operations began in
early 1977. In the summer of 1978, a truck driver died at the site
when liquid wastes dumped from his truck reacted with contents of
the receiving pond to create lethal hydrogen sulfide gas. A State
of Louisiana District Court ordered the site closed in late 1978.
Closure activities, completed in spring 1979, consisted of dewatering,
filling, and capping the open ponds. After closure, the State of
Louisiana continued to receive complaints about odors and surface
contamination in the swamp south of the site. Based on information
from investigations performed by the State in 1981 and 1982, the
Bayou Sorrel site was added to the Superfund National Priorities List
(NPL) in July 1982. '
Major Concerns and Issues
Community involvement relating to the Bayou Sorrel site has been
strong. Public interest in the site appears to have begun in early
1978. At that time, the Iberville Parish Police Jury notified the
Louisiana State Department of Health of its strong objection to the
disposal of wastes at the facility. The State Department of Health
responded with a letter to the site operators notifying them that
disposal of wastes was permitted only with department approval for
each specific waste load.
Several local residents formed the Concerned Citizens of Bayou Sorrel
in early July 1978. Their first meeting dealt primarily with odors
and potential contamination from the hazardous waste injection well
located in the town of Bayou Sorrel. Approximately 75 people attended
this first meeting. Public concern and interest were sUbstantially
elevated,when a truck driver was killed at the site on July 25. 1978.
A second meeting of the Concerned Citizens of Bayou Sorrel was held
in early August of 1978 and was attended by over 200 area residents.
Interest of the group expanded to include cleanup of the Bayou Sorrel
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In the fall of 1978, the only bridge leading to the site was burned
to prohibit truck access. An area newspaper alleged that the fire
was a result of area residents' frustration with what they perceived
as inaction by the State of Louisiana.
In response to continuing citizen complaints, the State of Louisiana.
in 1981, conducted a preliminary site investigation and installed wells
for long-term monitoring. After the EPA listed the site on its
. National Priorities List, the Iberville Parish Police Jury passed a
resolution to support clean up activities of the Bayou Sorrel site.
In 1979, more than 150 people living in the area filed a civil suit
against the owners of the injection well and the Bayou Sorrel site,
charging that both had been a nuisance for years and that fumes from
the open pits had harmed residents' health.
Activities to Elicit Input and Address Concerns
The Louisiana Department of Environmental Quality (LDEQ) assumed lead
responsibility from the Louisiana Department of Health. They responded
to numerous telephone calls from area residents concerning the injection
well and the Bayou Sorrel site. Subsequently, the EPA conducted site
inspections pursuant to the Comprehensive Environmental Response, Compen-
sation and Liability Act of 1980 (CERCLA).
The EPA issued a press release on March 19, 1984, announcing the start
of extensive remedial investigation and feasibility studies (RI/FS). At
that time, the Work Plan was made available to the public at the three
established strategically located respositories, for their review and
study.
Subsequent to the end of the RI/FS, the EPA issued a press release
to announce a public meeting held on February Z6, 1986, in the Police
Jury Room of the courthouse in Plaquemine, Louisiana. This meeting
was held to discuss the cleanup alternatives for surface and groundwater
contamination at the site.
A public comment period was established from February 1Z, 1986 through
March 5, 1986, during which both oral and written comments were received
by the EPA.
Continuing meetings have been held with the Responsible Parties at the
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Ill. SUMMARY OF PUBLIC COMMENTS RECEIVED DURING PUBLIC COMMENT
PERIOD AND AGENCY RESPONSES.
This public comment period on the Feasibility Study for the Bayou Sorrel
Superfund site was originally scheduled from February 12 to March 5,
1986. Tne last day to receive comments was officially extended to March
15. A public meeting was held on February 26, 1986, in P1aquemine,
Louisiana with approximately 80 people in attendance and 22 of those
making oral statements or asking questions. Five written statements
were received during the comment period. A summary of these comments is
provided below.
In addition to the public meeting, a briefing was held for local officials
on February 26, 1986. Present at this meeting were officers and members
of the Iberville Parish Police Jury and representatives of the Louisiana
Department of Environmental Quality, along with EPA and its consultants.
The Bayou Sorrel Feasibility Study alternatives were presented to members
of the Ibervi11e Parish Police Jury and the possible implementation of
the selected remedy by potentially responsible parties was discussed.
Comment 111
(United States Department of the Interior, Fish and Wildlife Service
Mr. Willie Hurdle - Iberville Parish Police Jury) .
The U.S. Department of the Interior, Fish and Wildlif. Service stated
that since the site is surrounded by open water and ba1dcypress/tupe1ogum
swamp with high fish and wildlife value, since the site is inundated
during high water periods, since large amounts of hazardous wastes are at
the site, and since the site is only a few feet above the normal water
table they recommend that at a minium the geomembrane cap and slurry wall
remedy be implemented at the Bayou Sorrel site.
EPA response to comment number 11
The geomembrane cap and slurry wall is one of the on-site remedies currently
being considered by EPA. However, the remedial investigation conducted
at the Bayou Sorrel site has not confirmed that waste constituents are
migrating from former disposal areas via groundwater. EPA feels that a
clay cap with a slurry wall around the former land fills and pond 4 only
is sufficient to protect human health and the environment. This remedy
will also include a mechanism in the monitoring program to determine
definitely whether migration is or is not occuring and if so the extent
of migration and the effect the migration might have on public health and
the environment. If such a remedy is implemented by res~onsib1e parties,
this mechanism would be included in a legal consent instrument and would
allow for additional remedial measures if necessary.
. -. -., - -', ",,... ~ "-. - . '. .. ~-.
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C omme n t 112
(Ecology Center of Louisiana, Dr. Velma Campbell)
The above comments oppose an on-site remedy (clay cap, geomembrane cap,
or geomembrane with slurry wall) because of one or more of the items
listed below.
These commentors feel that an in-place remedy is unsatisfactory because:
If constituents leak from the former waste disposal area, contaminants
will not be detected until after materials have escaped containment.
o The monitoring program will end before any contaminants are likely to
escape. .
o
o
If any contaminants are found in groundwater river or swamps, it would
be blamed on the site if wastes remain at the site.
o It is not credible to suggest that any entity will monitor to perpetuity.
o Clay cap alternatives are not disposal alternatives but rather long-term
storage.
o Deed restrictions would remove the land from recreation, commerce,
development, and natural processes of evaluation.
o The State or community would be left with the long-term burden of
overs i ght.
o Capping as ultimate remediation worsens the original situation because
it enshrines in legal agreements the existing non-viable situation it
is designed to correct.
o The Louisiana Legislature has determined that the southern part of
Louisiana is unsuitable for hazardous waste disposal. Land disposal
is to be phased out by 1991. It is inapproprate to propose a remedy
that would be illegal if it were a commercial operator.
o The area around the Bayou Sorrel Site is hydrogeologically active and
interconnected. In situ percolation rates suggest that the site may
leak in terms of Teet per year rather than fractions of inches.
EPA Response to Comment '2
The RIfFS conducted at the site by EPA does not indicate-that any extensive
movement of contamination has occurred. However, the monitoring program
designed for any in situ remedy would b~ designed so that any move~ent of
waste constituentS-from the containment areas would be detected early.
Tnis mOnltorlng plan would have a "trigger mechanism" to ensure that
additional remedial work is undertaken if significant contamination
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3
Even though the monitoring program described in the FS is for a minimum
of 30 years, EPA would reevaluate any monitoring program prior to expiration
to determine if additional monitoring is necessary.
The site monitoring program will be designed to ensure that contaminants
are unable to migrate to surface water (i .e. swamp, lake or river)
undetected.
Any monitoring progam implemented at the site by PRPs in conjunction with
an onsite remedy will be included in a legal instrument to ensure that
monitoring is conducted as scheduled.
Even though an onsite remedy would not result in destruction of wastes
and waste constituents, the geology at the site is such that waste
migration would not be extensive. The deed restrictions that will be
included in an onsite remedy would not entirely remove the Bayou Sorrel
site from recreation, commerce, and development. It will of course,
limit access to the site, especially the former waste disposal areas, and
limit other activities conducted at the site. This will include preventing
direct contact with waste disposasl areas, and activities that would
disturb the cap and other elements of an onsite remedy.
There is also concern that the State or local community would be left
with the burden of long term oversight. EPA will ultimately be responsible
for any oversight of remedial activities or maintenance and monitoring
activities. As in other areas of environmental concern and at other
sites. EPA would rely on the expertise of State officials and other local
environmental and health agencies as necessary. In sites where federal
money is used for remedial action, CERCLA requires. prior to providing
these remedial actions that the State enter into a contract or cooperative
agreement providing assurances that the State will assure maintenance for
the expected life of the action.
Capping as ultimate remediation will not worsen the existing situation by
enshrining in a legal agreement the non-viable situation it is designed
to correct. The legal agreement utilized to memorialize any remedial
action agreement with PRPs, will instead ensure that after remedial
action at the site. conditions do not revert to the current conditions.
After superficial remedial work at the site in 1978 and 1979, no provisions
were made to ensure that the site cover was maintained and no monitoring
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4
Comment '3
[Dr. Velma Campbell]
This commentor proposes remediation involving removal of waste for long
term proper storage or destruction because:
1. The land would be restored to a useful condition for commerce,
. recreation delveopment or nature. Also, nearby property values would
be preserved.
Facilities developed or converted for management of hazardous waste
may be utilized in the future for other purposes. Construction,
conversion and operation of these facilities would provide jobs for a
wide variety of local work force.
Two examples of this type of remedial action provided by this commentor
are:
2.
1.
Modify existing, underutilized storage facilites to contain the Bayou
Sorrel wastes and construct new facilities for long term storage.
Dispose of waste and wastes by offsite incineration in facilities
likely to be available in the next two years.
2.
Utilize kilns licensed and operating for the processing of recoverable
waste products.
EPAls Response to Comment '3
3.
EPA, in its FS, has evaluated the offsite incineration remedy suggested by
this commentor and found it to be much less cost effective and time
effective than other onsite and off-site remedies. Based on an estimated
volume of 1,000,000 cubic yards of waste and contaminated material at this
site, it could take eighty years to complete this remedy.
The long term storage proposed by this commentor would not only drastically
increase the cost of an ultimate remedy but would also increase the
exposure to the environment because of the additional handling, and
transportation.
EPA is not aware of the kilns licensed and operating for the processing
of recoverable waste products discussed in this comment. Even if these
kilns were available 10cal1y,the volume and nature of the Bayou Sorrel
wastes would be prohibitive to this type of operation. First of all,
there is a wide range of wastes that were mixed at the Bayou Sorr~l site.
These include pesticides, petroleum refinery wastes, petrochemical wastes,
and other industrial wastes. It would be virtually impossible to recover
portions of this mixture. Compounding the problem is tne method of waste
stabilization that was used when the site was originally closed in 1978-79.
The wastes were at that time mixed with large quantities of soil and
other stabilizing agents. The total volume of waste/contamimated soil is
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Also, this commentor discusses the possibility of storing the Bayou Sorrel
wastes to allow access to the materials for research into chemical mix
behavior or 50 that commerical ventures. may be developed to extract
valuable components from the waste mixture. Again, the extensive quantity
of the soil-waste mixture would prohibit these uses and because of the
nature of the mixture, as discussed above, it would be virtually impossible
to separate the waste components. Likewise, it is not likely that this
large quantity of hazardous waste mixture would ever be used for research
purposes. Even so, some form of ultimate disposal would be necessary at
csome point in time.
Comment '4
[Dr. Velma Campbell]
This commentor suggests that further chemical analysis of wastes and
characterization of wastes for suitability of disposition is necessary.
EPA Response to Comment 14
While EPA performed limited analyses of waste during its site Remedial
Investigation, sufficient information is available concerning the nature
of the wastes at the Bayou Sorrel site. Extensive information concerning
categories of waste and specific wastes at the Bayou Sorrel site is
available in the form of site records, information provided by companies
in l04(e) responses, 'and other documents. Also, State employees have
provided EPA with invaluable information from first hand observations of ..
site activities during actual operations and during closure operations
in 1978 and 1979. State personnel were on site regularly during closure
of the site and have provided information to EPA concerning locations of
waste, stabilization techniques, etc. EPA does not feel that additional
sampling and analyses of waste is necessary.
Comment 15
[Michael Tritico - RESTORE]
This commentor feels that the danger at the Bayou Sorrel site has not
been properly documented. Specifically this commentor mentions that there
are not enough monitoring wells testing enough strata and for enough
chemicals to be certain that heads of plumes have been located nor to
demonstrate the direction and speed of movement.
EPA Reponse to Comment '5
Since 1981, a total of 23 monitoring wells have been installed at the
Bayou Sorrel site and groundwater samples analyzed. Four of these wells
penetrate into the deeper plaquemine aquifer and the remainder are screened
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wells (including recent Remedial Investigations conducted by EPA and the
Bayou Sorrel Task Force) do not indicate that there is extensive migration
of waste constituents from former waste disposal areas. Each sample was
analyzed for the 129 inorganic and organic constituents each time. Each
of these monitoring wells has been situated so that former waste disposal
areas are virtually surrounded and the direction of any migration would
be detected.
Conwnent '6
[Michael Tritico - RESTORE]
(j
This commentor does not want delays in solving the problem because the
Bayou Sorrel site is often flooded, is subject to catastrophic scouring
during a 1eve crevasse, will be submerged year round within a hundred
years, is hydraulically connected with local aquifers, and toxic materials
cannot be left ~~ because they will not stay ~ situ.
EPA Response to Comment 16
EPA also feels that expeditious remedial action at this site is appropriate.
We are aware that delays have come up during investigative work at the
site but prior to initiating any remedial action at a Superfund site, EPA
is obligated to define the extent of the problem and select the cost
effective remedy that will protect human health and the environment.
Evidently, this commentor equates "solving the prob1em"'with the total
removal and disposal or treatment of the waste and related contaminated
soil at the Bayou Sorrel site. EPA is aware of the problems o~ frequent
flooding, potential of catastrophic scouring in the event of a levee
crevasse and that sea level around the world is rising. Each of these
considerations will be addressed individually and collectively during the
design of the remedy and monitoring program at the Bayou Sorrel site.
Even though the Bayou Sorrel Site is connected with local aquifers, the
characteristics of the soils at the site are such that migration of
hazardous constituents from former waste disposal areas will be minimal.
No contamination of the P1aquemine (deeper) aquifer has been detected;
contamination is not expected because of the upper hydraulic pressure
of this aqui fer.
Some waste constituents have been detected in the shallow aqufer but at
low levels «100 ppb) and mostly in isolated instances (i.e. no evidence
of leachate plumes. The concern that toxic materials cannot be left in
place because they will not stay in place is unfounded. Results of
extensive sampling (EPA, State, and PRPs) of monitoring wells, soil,
surface water, and biota at the site indicate that the waste is staying
in place. The long-term monitoring and maintenance that.wou1d be included
in any onsite remedy would ensure that the integrity of remedial actions
is maintained and enable EPA to determine the extent and direct'ion of any
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Comnent 17
[Michael Tritico-RESTORE]
This commentor feels that artesian pressure from below and inundative
pressures from above will continue the spread of dangerous materials
until those materials are removed.
[PA Response to Comment 17
The studies conducted at the Bayou Sorrel site do show that the hydraulic
gradient of the lower (Plaquemine) aquifer is above land surface most of
the year. However, EPA feels that this condition, instead of dispersing
waste constituents, would prevent migration of these waste constituents
downward to the Plaquemine aquifer. The inundative pressures from
above" would be prevented from contacting the wastes and contaminated
soil by means of a clay cap. The design of this cap would be such that
not only would surface water be prevented from contacting the waste or
contaminated soil by a clay cap and geomembrane liner, but surface water
would also be prevented from contacting the cap by a layer of topsoil and
a sand drainage layer above the clay cap. There will also be a drainage
layer below the cap that will collect any waste leachate caused by the
artesian pressures of the P1aquemine Aquifer along with pore wat~r generated
because of the weight of the cap causing settling.
Conment '8
[Michael Tritico-RESTORE]
This commentor suggests that a slurry wall does not seal from below nor
above nor from the side in the case of a levee crevasse. Also, a slurry
wall must be keyed into a suitable aquiclude and none exists at the site.
[PAIs Response to Comment '8
EPA agrees that a slurry wall does not seal from the top nor bottom; the
. function of a slurry wall is to prevent lateral migration of contaminated
groundwater or leachate. If a slurry wall were utilized at this site, it
would be designed so that lateral migration would not occur. This would
include installation of the wall below the bottoms of waste disposal
areas and would cut off the more permeable lenses beneath the site.
Upward migration of contaminated groundwater would be collected by the
drainage system beneath the cap and would be prevented by the cap system
itself.
Concerning the issue of no suit~ble aquiclude at the sit~, EPA studies
have shown that the soils underlying the Bayou Sorrel site are of suffi-
ciently low permeability to prevent signifi.cant downward migration.
This, coupled with the artesian pressure of the lower aquifer, would act
to preclude downward migration of contaminated groundwater, as discussed
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8
However, the RI conducted at the Bayou Sorrel site did not confirm that
waste constituents are migrating from the former waste disposal areas via
groundwater, and a slurry wall is not necessary around the entire site.
Comment '9
[Michael Tritico - RESTORE]
Indications from preliminary monitoring data have not been correlated
with data indicating that chlorinated hydrocarbon and an alkaline influence
are destructive to clay soils. This comment was evidently based on a
three page letter report (attached to the commentor's letter) concerning
sodium hydroxide effects and ethylene dichloride light end wastes effects
on in situ clay. This comment was also made by Mr. Tritico at the February
26,:[986 public meeting.
EPA Response to Comment *9
In this commentor's oral comments at the February 26 public meet'ing he
mentioned that at the Bayou Sorrel site there are pH's approaching 10 and
chlorinated hydrocarbon reported in large quantities.
EPA is not aware of any chlorinated hydrocarbons being reported in large
quantities during the RI at this site, nor in other studies conducted by
the LDEQ and the PRPs. Concentration of chlorinated hydrocarbons were
generally less than one part per million (ppm). The report submitted by
Mr. Tritico was a laboratory test conducted for a specific site using
soil from that site. The test was conducted using ethylene dichloride
(EDC) light end wastes; the report does not give the concentration of
EDC, but it is assumed that it would approach 100'. Since concentrations
of chlorinated hydrocarbons at the Bayou Sorrel site are <1 ppm, comparison
of the characteristics at Bayou Sorrel to results of this report would
not be appropriate.
The report submitted by Mr. Tritico also dealt with laboratory tests of
effects of sodium hydroxide (Na OH) on in situ clay permeability. This
report discusses that the clays from the-test site were destroyed by
saturating with a SO~ Na OH solution; this saturation raised the pH of
the test soil to 13 before destruction of the clay occurred.
The highest pH measured at the Bayou Sorrel site during studies conducted
by EPA, LDEQ and PRPs appears to be 9.S (this was of waste in disposal
ponds prior to the 1978-79 closure of the site) except for two isolated
monitoring well samples by PRPs in 1984.
Since the report included with Mr. Trictico's letter is -'based on a Mworst
case" situation concerning pH and chlorinated hydrocarbons, it is impossible
to infer the effect that the low chlorinated hydrocarbon concentrations
and much lower pHs that exist at the site may have 'on in situ clays. In
any event, the monitoring program at the site will allOW ~to constantly
evaluate the migration of contaminants from the former waste disposal
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Comment 110
[Michael Tritico - RESTORE]
This commentor suggests that "a thoroughly inadequate amount of attention
has been given to the "removal alternative". Mr. Tritico suggests that
the wastes be transported by barge to GSU's Riverbend Nuclear Station at
Starhi", Louisiana. There, the commentor proposes, the waste could be
processed using the plasma torch technology, with small volumes of ash
and salt remaining. If the plasma torch method does not fully degrade
the contaminated material, the comment or recommends that other tec~niques
could be applied such as radio frequency heating, high temperature fluid
wall reactor, infrared incinerator, supercritical water oxidation, molten
salt or molten glass technologtes set up alongside each other and operated
as a flexible system.
EPA Response to Comment *10
In evaluating alternatives for the Bayou Sorrel site, EPA retained two
-removal" alternatives for detailed evaluation. These alternatives (off-
site disposal at a RCRA facility and onsite incineration) are discussed
in detail in the Feasibility Study developed by EPA. Transportation
alternatives for the offsite disposal included barge transport as Mr.
Tritico mentioned. The waste treatment alternatives proposed by Mr.
Tritico were not evaluated by EPA, however, because these alternatives
are not proven technologies. The National Contingency Plan (40 CFR
300.68(h)(2)(i)) requires that EPA place "... emphasis on use of established
technology" in its detailed analysis of alternatives.
Also, Mr. Tritico mentions that volumes of ash and salt remaining will be
minimal. Because of the physical state of wastes remaining at the Bayou
Sorrel site, this is not a valid statement. When the site was closed in
1978-79, wastes remaining at the site were stabilized using soil and
other addatives such as kiln dust and portland cement. Volume reduction
by incineration or other thermal treatment would be, at best, minimal and
volume could possibly increase due to fluffing of the treated material
during the treatment process.
Comment III
Police Jury - Iberville Parish; Walter Allen - Concerned citizens of
Bayou Sorrel.
These commentors ask the question "Who are the members of the Bayou Sorrel
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EPA Response to Comment. III
As EPA discussed at the February 26, 1986 public meeting, the Bayou Sorrel
Task Force (iSTF) is composed of a group of Potentially Responsible
Parties who voluntarily banded together to negotiate with EPA concerning
remedial activities at the Bayou Sorrel site. The BSTF, independent of
EPA, has conducted its own RIfFS at the site and has expressed a willingness
to implement their recommended alternatives (a clay cap remedy similar to
EPAls clay cap alternative).
Comment #12
Iberville Parish Police Jury, Walter Allen - Concerned Citizens of Bayou
Sorrel, Andrea Allen.
These commentors asked "Who detenni nes what is cost effect he? II
EPA Response to Comment 112
The National Continagency Plan requires that in selecting a remedial
alternative for a site, the decision maker (in the case of Bayou
Sorrel, the Regional Administrator) among other things, to take into
consideration the cost of implementing the re~dia1 actions including
oper.ation and maintenance costs. An alternative that far exceeds the costs
of other alternatives and does not provide substantially greater protection
of public health or the environment should be excluded. The NCP requir~s
that the Agency select the cost effective alternative that effectively
mitigates and minimizes threats to and provides adequate protection of
public health and welfare and the environment considering cost, technology
and reliability of the remedy. The Regional Administrator will make this
decision based on infonnation provided in the RIfFS and other information
provided by EPA staff and consultants. .
Comment 113
Ibervil1e Parish Police Jury, Walter Allen - Concerned Citizens of Bayou
Sorrel, Andrea Allen, Leslie Ann Kirkland
The above commentors asked the question .Will local people have any input
into the remedial alternative select1on?N
EPA Response to Comment 113
As discussed at the pUblic meeting, the purpose of the pUblic comment
period and public meeting is to receive comments on the Feasibility Study.
The review and comment period precedes selection of the ~emedial response
and the summary of public comments is one of the documents utilized by
the decision maker in selecting the appropriate remedy for any particular
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. Comment #14
[Concerned Citizens of Bayou Sorrel, Iberville Parish Police Jury]
These commentors requested an extension of time for submission of comments
on the Feasbi1ity Study.
EPA Response to Comment 114
E~A agreed at the February 26 Public meeting to extend the public comment
period from March 5 to March 15, 1986.
Comnent 115
[Dale Bouquet - Ibervi11e Parish Police Jury, Walter Allen - Concerned
Citizens of Bayou Sorrel]
These commentors requested that EPA provide financial aid to Iberville
parish so that the parish attorney and Parish engineer can be involved
in investigations at the Bayou Sorrel site. Also, these commentors
requested that EPA provide money to assist in a Parish investigation of
soil and water (at the site).
EPA Response to Comment *15
Section 104 of the Comprehensive Environmental Response. Compensation and
Liability Act of 1980 (CERCLA) provides that where it is determined that
a State or political subdivision of a State has the capacity to carry out
any or all of the actions authorized under Section 104 of CERCLA, EPA may
enter into a Contract or Cooperative Agreement ~ith that entity to take
those actions using fund monies. In the fall of 1982, the Louisiana
Department of Natural Resources (now Department of Environmental Oua1ity)
requested that EPA enter into such a Cooperative Agreement for the RIfFS at
the Bayou Sorrel site. EPA allocated money for the State to conduct
these studies contingent upon no responsible parties being willing to
undertake remedial activities at the site. No responsible party was
willing to voluntarily undertake remedial activities. However, the State
subsequently withdrew its application for a Cooperative Agreement and EPA
proceeded with the RIfFS.
These commentors are requesting fund monies so that the parish can be
involved in the investigation at the Bayou Sorrel site and also conduct
its own studies. EPA feels that the studies authorized by Section 104 of
CERCLA have been completed and at this point no further investigation is
needed. The next step in the remedial process, as outlined in the NCP,
is Remedial Design. EPA plans to negotiate with the Bayou Sorrel PRPs
for the Remedial Design and also the following phase, Remedial Action
(construction). All these actions, if implemented by th~ PRPs, will
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Comment 116
[Iberville Parish Police Jury, Walter Allen President - Concerned Citizens
of Bayou Sorrel]
This comment questions whether the remedial alternatives described in the
FS apply to only the former waste disposal areas or whether they also
apply to any areas where wastes have migrated from the waste disposal
areas. .
EPA Response to Comment 116
As explained in the FS, there are some isolated areas where surface
contamination has been documented. These areas are in the vicinities of
former waste disposal areas and may be due to either seepage or spillage
during 78-79 closure activities. These areas will all be included in the
ultimate remedy for the Bayou Sorrel site. For the geomembrane cap
alternative this contaminated soil would be placed under the cap above
the former waste disposal areas.
Comment 117
[Iberville Parish Police Jury, Walter Allen, PRESIDENT - Concerned Citizens
of Bayou Sorrel, Andrea Allen]
These commentors questioned how long the waste at Bayou Sorrel will remain
toxic.
EPA Response to Comment 117
With the geomembrane cap remedy, the wastes and contaminated soil would
be protected from natural destruction mechanisms such as oxidation,
sunlight, aerobic microorganisms, and other elements. Even though there
will be some degradation of those wastes it will be minimal; therefore,
the wastes, for all practical purposes, would remain toxic forever.
Comment 118
(Iberville Parish Police Jury, Walter Allen, President - Concerned Citizens
of Bayou Sorrel]
These commentors are concerned with what chemicals are on site and what
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EPA Response to Comment *18
As discussed in the FS, the wastes disposed of at the Bayou Sorrel site
generally talt into one of the following three categories:
1. Process wastes from pesticide/herbicide manufacturing including
distillation residues, contaminated packaging, and miscellaneous
wastes.
2.
Sulfide-containing wastes (scrubber b10wdown and spent caustic) from
hydrocarbon processing and exploration activity.
Spent wash solutions from boiler-cleaning and process equipment-
cleaning contractors.
3.
Soil sampling results indicate that the former ponds contain an assortment
of organic compounds, including herbicides and pesticides. During its
investigation of the site EPA has developed an extensive list of compounds
that may have been disposed of at the Bayou Sorrel site. Since ~any of
these compounds may not be hazardous wastes or hazardous substances and
since these compounds may decompose with time into other compounds, EPA
analyzed all samples for the full list of 129 priority pollutants.
As discussed in previous comments, leaving these wastes in place should
not adversely affect the areas. EPA will require long term monitoring
and maintenance to ensure that hazardous substances are not leaving the
site.
Comment 119
[Iberville Parish Police Jury; Walter Allen, President - Concerned Citizens
of Bayou Sorrel]
Several commentors were concerned with various aspects of access/development
restrictions suCh as: will development on and around the site be limited;
how will people be kept off site; will site be safe to hunt and fish
after remediation; etc.?
EPA Response to Comment 119
Each of the onsite alternatives has the same security features as part
ot the long term monitoring and maintenance activities. These include a
six foot high chain-link fence around the capped areas. gravel access
roads around the fenced areas to encourage persons on the site to go
around rather than over capped areas. and signs warning of the waste
disposal areas. Inspection and repair of these security"features will be
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Cotmlent 120
[Iberville Parish Police Jury, Walter Allen, Concerned Citizens of Bayou
Sorrel, Mr. Bouquet]
This group of cOtmlentors is concerned with liability for this site once
the Remedial Action is completed. Specific questions asked include:
what happens if contaminantion occurs after cleanup? Are the Iberville
Parish Police Jury and State responsible? Will money be available for
future testing of soil, groundwater, etc.? If so, for how long and how
much per year?
EPA Response to Cotmlent #20
As we discussed at the public meeting, EPA plans to negotiate with PRPs
for voluntary implementation of the remedy at the Bayou Sorrel site. If
these negotiations are successful, EPA will require that the PRPs conduct
long term monitoring and maintenance at the site. If the wastes remain at
the site, the PRPs would retain liability for problems that develop in
the future at this site; this future liability is included in the Consent
Decree.
If Federal funds were to implement Remedial Action at this site, the
State would have to provide all future maintenance of the remedial action
for tne expected 1 ife of the remedy. Thi.s woul d not mean that the State
would assume liability for the site, but would assume responsibility for
maintenance. .
Future testing of media at the site will be the responsibility of the
PRPs pursuant to the Consent Decree. EPA of course, would oversee this
sampling, including analysis of a limited number of samples for verification
of accuracy of PRP analyses. It is impossible, however, to determine how
much money per year will be available and for how long it will be available.
Cormlent 121
[Mrs. Oswald P. Templet, Mr. John J. Battieste]
These commentors own property and/or have water supply wells in the area
of Bayou Sorrel and are concerned that wastes may have migrated off-site.
EPA Response to Comment '21
In conducting the Remedial Investigation, two of the main concerns at the
Bayou Sorrel site were that waste constituents might leave the former
disposal pit via ground water or surface water. Both of ~hese pathways
of migration have been sampled extensively by EPA, LDEQ and PRPs and no
offsite migration of contamination has been detected. Also, as discussed
in previous responses, both these pathways of migration will continue to
be monitored as part of the long term operation and maintenance after
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Comment 122
[Mr. Roy Zito, Mr. Darrel Stevens - Citizen Activists Against Pollution]
These commentors were concerned that organisms living at the site might
be contaminated or become contaminated in the future.
EPA Response to Comment '22
Organic analysis was performed on tissue samples of catfish, bream,
crayfish tail meat, and crayfish green gland, all collected onsite. Fish
samples were collected from the borrow lake and small onsite pond, and
crayfish from numerous shallow standing water areas onsite. No organic
compounds of non-biological origin were found in any sample, and inorganic
results were typical for uncontaminated tissue. Continued monitoring of
oryanisms onsite will be included as part of the long term operation and
maintenance of the remedy.
Comment 123
[Walter Allen, President - Concerned Citizens of Bayou Sorrel, Andrea
Allen]
These commentors had specific questions concerning site conditions and
certain aspects of the remedial alternatives. These questions included:
What is a slurry wal~? How deep is the proposed slurry wall? How deep
were wood fragments found at the site? Will wood fragments cause a
conduit through the 50il when the wood decomposes.
EPA Response to Comment '23
The slurry wall proposed for the Bayou Sorrel site is of the soil bentonite
type. In this type of slurry wall, a trench (approximately 3 ft. wide) is
excavated around the waste disposal areas to a specified depth.
The spoils from this trench are then mixed with bentonite (a form of
clay) and pushed or pumped back into the trench. The clay absorbs water
and swells resulting in a low permeability underground containment wall
around the waste disposal areas. The purpose of the slurry wall is to
prevent groundwater from migrating into or out of the waste disposed
areas. The depth of the slurry walls at the Bayou Sorrel site would vary
according to depth of waste, areas of higher permeability etc., but would
generally be 30-40 feet deep.
Concerning the depth of wood fragments at the site, soil borings were
done across the entire site, some to a depth of 80 feet. Indications are
that 25 or 30 feet was the deepest locations where wood fragments were
found. There is no indication that wood fragments at this site would
form major conduits for migration of contaminated ground water, since in
place permeability tests at this site included many of the bore holes
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Corrment 124
[Robert Mooney - Plaquemine City Coucil]
This commentor was concerned with two aspects of groundwater migration at
the Bayou Sorrel Site:
1.
Laboratory determination vs field determination of soil permeability
and, -
2. Hydraulic balance at or near the site may change.
EPA Response to Comment 124
EPA agrees with this corrmentor that there may be differences in permeability
determined in this field vs Laboratory. However, based on data collected
by EPA and others concerning permeability at the site, EPA feels that
there is low potential for groundwater migration at the site. In studies
done at this site, both methods of determining permeability have been
used for comparison. The reason for this is there are arguments that
each method may be more accurate than the other. Utilizing all available
permeability data and the fact that no significant contaminant migration
in groundwater has been detected, EPA feels that soils at this site are of
sufficient impermeability to prevent contaminant migration in groundwatpr.
EPA also agrees that the Hydraulic Balance may change at the site. This
is one of the items that will be monitored at this site and if data
i"dicate that additional corrective actions may be necessary in the
future, EPA could then ensure the implementation of that action.
Comment '25
[Jesse Wilson - Iberville Parish Police Jury, Andrea Allen]
These commentors asked what would constitute a true emergency at the Bayou
Sorrel site and whether EPA has a funding mechanism to handle emergencies.
EPA Response to Corrment '25
In determining the appropriate extent of action to be taken at a given
site, EPA reviews all site data to determine if a Remedial Action is
appropriate. If it is detenmined that there is an immediate risk to
public health or welfare or the environment, the EPA may take action to
control the threat. Criteria used to evaluate a site for a removal action
include:
1. Contamination of drinking water supplies;
2. Hazardous substance, etc. stored in bulk container;
3. Threat of fire or explosion; .
4. High levels of hazardous substances, etc. in soils at or near the
surface that may migrate;
5. Exposure to hazardous substances, etc. by nearby populations,
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The removal action may be conducted either by utilizing Superfund money,
or whenever possible, by the Responsible Parties.
Conment 126
[Mr. Milton Vaughn]
This commentor is concerned with the effect that buried containers
wh~ch might rupture would have on releasing contaminants to the groundwater.
EPA Response to Conment '26
One area of the Bayou Sorrel site was utilized specifically for drum
disposal. Through our extensive field investigations and record reviews
(including information provided by LDEQ) , we have determined that most
containers disposed of at the site were emptied and crushed prior to
disposal. Another area of the site was rumored to have received filled
drums but investigation (magnetometer survey) failed to confirm the
presence of drums in that a rea. .
Conment 127
[Mr. Milton Vaughn, Mr. Rod Ritterman, Mr. Walter Allen]
Thes.e convnentors expressed concerns wi th monitori ng well sand. oi 1 well s
at the site. One of these commentors wanted to know what keeps contamination
from following the well bore and contaminanting, the (Plaquemine) aquifer.
Another wanted to know if the integrity of mo~toring' wells onsite is
checked as an injection well is checked. The third concern deals with
the effect that an existing oil well on the site would have on waste
migration.
EPA Response to Comment '27
In any field investigation at a hazardous waste site where soil borings
of any type are conducted, every precaution is taken not to contaminate
any areas because of improper constructions of the boring (or well). EPA
and contractors in the hazardous waste field typically utilize some form
of sealer between the borehole and well casing. This sealer is normally
a cement-bentonite mixture placed in the void from above the screening
material to the ground surface. In the case of bore holes that are not
cased as monitoring wells, the bore holes are usually grouted to the
surface with the same mixture. This grout mixture will prevent contamination
from migrating downward along the bore hole.
EPA does not test the integrity of its monitoring wells as is done with
injection wells. Injection wells are normally operated under very high
pressure, with liquids being forced into the ground by this high pressure,
whereas monitoring wells are for the purpose of removing ground water
from the ground, usually by means of a bailer or some form of pump and
would not stress this well casing. However, visual inspections will bp.
made of monitoring wells as part of the overall monitoring plan and data
will be continually evaluated which in itself could indicate problems
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The oil well found on site is located in the borrow lake away from
contaminated areas and should not be affected by waste from the site.
any event, the well has been abandoned and is no longer in use.
In
Comment '28'
[Mr. Milton Vaughn, Mr. Wilson, Andrea Allen, Robert Mooney, Darrel Stevens]
These commentors had several comments dealing with the problems of installing
a clay cap in southern Louisiana, one being that the clays in the area
are "fat" clays which upon drying out will shrink and crack. Another is
that the area where the site is located is subject to frequent flooding
and water would come up underneath the cap.
EPA Response to Comment 128
Any cap installed at the Bayou Sorrel site will be designed to alleviate
the problems mentioned by the above commentors. Any clay soil has a
tendency to shrink and swell in relation to the moisture content of the
soil. This problem will be addressed in two ways at the Bayou Sorrel
site. First, the cap is designed so that it is protected by sufficient
topsoil and vegetation to prevent dessication of the clay. Secondly, the
long term monitoring and maintenance will provide for periodic visual
inspections of the capped areas so that potential problem areas could be
detected. Also, the geomembrane layer over the clay will assist in
preventing dessication and will provide an extra impermeable layer in the
event the clay cap does fail. .
The cap itself will be designed so that any flood waters encroaching on
the site would not pond on capped areas. The cap will be keyed a few feet
into the native clays at the site so that flood waters cannot enter
under the cap. In the event any surface waters were able to contact
wastes, any contaminated water would be collected by the drainage layer
installed directly over the waste.
Comment '29
[Nolan Henson, Mr. Bouquet]
These commentors were concerned that the proximity of the Bayou Sorrel
site to the Atchafalaya River Flood Protection levee might cause problems
either because the levee might be moved closer to the site or there could
be a catastrophic levee failure near the site.
EPA Response to Comment '29
EPA is not aware that the Corps of Engineers is planning-to move the levee
closer to the Bayou Sorrel Site. If this were to happen and if it did
affect the Bayou Sorrel site, t.here would be a gradual change and any problems
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'Concerning the catastrophic failure of the levee, this problem wi]l have
to be taken into consideration during the design phase of the remedy.
The cap could be designed to withstand this sort of catastrophic failure
if it were to nappen.
Comment 130
The majority of commentors at the pUblic meeting and those submitting
written comments favored the removal alternatives at the Bayou Sorrel
si.te. This would involve excavation of the wastes and contaminated soil
for transportation to a secure, RCRA compliant landfill.
EPA Response to Comment 130
Although this Remedial Alternative would be an effective, reliable method
of site remediation, there would still be major problems and efforts
associated with this remedy. This alternative would increase the short
term risk to site workers, the environment, and public health since waste
would be excavated and exposed prior to transportation to an offsite
disposal area. Also, there would be an increased risk from traffic
accidents due to the number of truckloads of waste that would be hauled
from the site.
Also, cost would be an important consideration with this remedy. Because
of the enormous volume of material to be excavated, transported and
disposed of the cost for this remedy would be over $500 million. Since
this extensive a remedy is not necessary at the Bayou Sorrel site to
protect human health and the environment, this would not be the most cost
effective remedy. .'
Comment 131
Several commentors were concerned with the injection well and associated
pits located near the Town of Bayou Sorrel approximately 6 miles from the
site. Most wanted an investigation and monitoring of this facility,
including cleanup of the abandonded pits located at the well.
EPA Response to Comment 131
The injection well at Bayou Sorrel is an active facility that is currently
regulated pursuant to the Resource Conservation and Recovery Act (RCRA)
and the Safe Drinking Water Act.
Current regulations require that prior to issuance of a RCRA permit, any
former disposal areas at a facility must be addressed. Also prior to
issuance of a RCRA permit, a public meeting must be conducted to receive
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COtmlent '32
[Bayou Sorre-1- Task Force]
On-site incineration and off-site landfill disposal are inappropriate
remedial technologies for the site. They place the population in needless
risk of traffic injury and exposure to wastes, overwhelm limited landfill
capacity and do not provide incremental benefits to balance these negative
effects.
EPA Response to Comment #32
EPA agrees that On-site incineration and off-site landfill disposal are not
the most cost effective alternatives which protect human health and the
environment. EPA is no longer considering these two remedies.
Conment '33
[Bayou Sorrell Task Force]
There is no demonstrated groundwater contamination at the site at the
present time which requires slurry wall construction. The risks of slurry
wall construction are considerable, the costs of wall construction are
unpredictable, and the effectiveness of a completed slurry wall is not
assured.
EPA Response to Conment 133
Even though extensive contamination of groundwater at the Bayou Sorrel
site has not been demonstrated, organic analytical results indicate the
possibility of organic contamination of shallow groundwater. This
contamination is at low levels and does not appear to be widespread.
Based on this data and the fact that the soils in the vicinity of the
site are relatively impermeable, EPA feels that a slurry wall around the
entire site is not necessary at this time. However, a mechanism would be
included in the consent document to require implementation of additional
remediation should contamination be detected in groundwater through the
monitoring program. This will be included as part of the overall monitoring.
Data generated through this program can be evaluated after a period of
years to detenmine if additional remediation is necessary.
COIIIIIent 134
[Bayou Sorrel Task Force]
The caps designed for capping alternatives .are too massive for site
cooditions. They contain two unnecessary sand layers and are too great in
areal extent. Unnecessary and extensive settlement will occur from the
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. 6EPA Response~ Comment *34
EPA is aware of the soil conditions at the site and the problems with
settling at the site. These problems can be overcome through design of
the cap, with features such as preloading for settlement prior to beginning
actual cap construction. This cap design is necessary to prevent surface
water from contacting wastes and contaminated soil along with prevention
of direct contact with waste by people or wildlife. The two sand layers
are included in the cap design as drainage layers. The sand layer
immediately above the waste can be modified to include less sand and an
additional geofabric layer for pore water drainage. The first is to be
located directly above waste and below the cap. This layer would intercept
pore.water squeezed out of the soil by cap settlement and allow it to be
collected for disposal. The second sand layer is to be placed above the
clay cap and geomembrane and below the top soil layer. This sand layer
would prevent surface water fr~m reaching the cap.
Comment '35
[Bayou Sorrel Task Force]
The caps designed for the cost evaluation of capping alternatives contain
needless costly design elements, i.e., a surface water run-off collection
pond, security during construction, an on-site laboratory, a below grade
barrier to burrowing animals and a passive gas vent system which are not
protective of human health and the environment.
EPA Response to Comment '35
While the features mentioned above may be replaced by other means of
control, the functions they are designed to address are necessary. For
example, if people are protected from direct contact with hazardous
substances or other dangers during construction, a security guard may not
be necessary. Each of these elements that the Bayou Sorrel Task Force
feels are "needless" can be addressed during the Remedial Design phase
prior to implementation of the remedy. .
COIIII1ent '36
[Bayou Sorrel Task Force]
The cost of a geomembrane is stated as being insignificant to the total
cost of a cap. Inclusion of a geomembrane escalates remediation costs an
additional $1.2 million and provides only a minimal addition level of
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EPA Response to Comment '36
Generally, the geomembrane cap alternative meets the current RCRA guidance
and this alternative represents in-place closure in accordance with
current RCRA regulations and guidance. This geomembrane layer would
effectively isolate the contamination from direct contact and, in addition,
add an extra layer of impermeability to effectively control infiltration
and waste seepage. In addition, this geomembrane would add an extra
me~sure of protection if the clay cap failed due to differential settling
or other problems.
Comment '37
(Bayou Sorrel Task Force]
Post-closure ground water monitoring is proposed to be semi-annual for 30
years. Semi-annual monitoring in early years is appropriate because of
the possibility of altering ground water velocities during and immediately
following construction. In later years when ground water velocities
return to their very slow rates, semi-annual monitoring is not appropriate.
EPA Response to Comment 137
As the above commentor states the post-closure monitoring period is for a
minimum period of thirty years. Even though the FS calls for semi-annual
monitoring, this frequency could be reduced, depending on data collected
during the monitoring ~rogram.
Comment '38
(Bayou Sorrel Task Force]
The Task Force does not agree with much of the EPA cost estimating
assumptions and methodology. However, for comparison purposes only,
properly using that methodology on the BSTF cap design results in a
capital cost estimate that is 8% less than the lowest cost EPA capping
alternative. This lower figure is based on (A) not changing the BSTF 190
mil geofabric to a composite geofabric/geo-net/geofabric and (B) not
using an erosion control mat on the gently sloped 4% edges of the BSTF
cap. The clay cap remedial alternative designed and configured in the
Bayou Sorrel Task Force Feasibility Study remains a remedial alternative
that effectively mitigates threat to, and provided adequate protection
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EPA Response to Comment #38
EPA does not feel that the clay cap alternative proposed by the Bayou
Sorrel Task Force provides adequate protection to pUblic health and the
environment. Many details of cap construction will need to bp. worked out
during the design phase of remediation Design modification may be made
that will save money, but in no case will these modifications be allowed
to erode the integrity of the cap design.
Comment 139
[Louisiana Department of Environmental Quality]
The Louisiana Department of Environmental Quality (LDEQ) contends that,
all other things being equal, the most desirable action of the Bayou
Sorrel site is total removal or distruction of wastes. The LDEQ states
that if an on-site remedy is selected, precautions should be taken to
ensure that waste or constituents are not released. It is recommened
that the areas of the old pits on site be included in a slurry wall and
the cap design recommended by the BSTF be utilized to minimize the amount
of settling.
EPA Response to Comment #39
EPA feels that the removal and destruction options are not cost effective
remedies at the Bayou Sorrel site. EPA has had subsequent discussions
with LDEQ personnel and has furtber reviewed cemments provided by the
BSTF. Based on this information, EPA and the State agree that modifications
can be made to EPAls geomembrane cap design that will decrease the overall
weight of the cap but will not affect the efficiency of the cap. Also,
EPA and LDEQ personnel agree that a slurry wall is not necessary at this
time except in the vicinity of the old landfill cells and pond 4 area.
The monitoring program would be extensive and not only would allow for
early detection of waste migration but would include a mechanism to
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