United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R06-86/014
September 1986
&EPA
Superfund
Record of Decision
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~
TECHNICAL REPORT DATA
(PfttlSt nad Instructions on tht rtvtnt IHfon co,""fttinlJ
1. RI,.O"T NO. 12. 3. RECIPIENT'S ACCESSION NO.
EPA/ROD/R06-86/014
4. TITLE AND SUBTITLE 5. REPORT DATE
SUPERFUND RECORD OF DECIS ION seDtember 30, 1986
United Creosoting Site, TX 6. PERFORMING ORGANIZATION COOE
7. AuTHORCSI 8. PERFORMING ORGANIZATION REPORT NO.
e. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORT AND PERIOD COVERED
U.S. Environmental Protection Agency Final ROD ReDOrt
401 M Street, S.W. 14. SPONSORING AGENCY CODE
Washington, D.C. 20460 800/00
15. SUPPLEMENTARY NOTES
18. ABSTRACT
The united Creosoting site is a 100-acre tract of land located in the City of Conroe,
Montgomery County, Texas. '!be site is an abandoned wood preserving facility over.which
two new businesses and a residential subdivision have been built. The site operated
from 1946 to 1972, treating wood with creosote and pentachlorophenol (PCP). Prior to
salvage and removal operations in 1972, the site contained a coal-tar distillation
still, a processing building, tanks and pressurecyl~n~e~s, two waste ponds, and several
areas where treated lumber, was stored., .The only remaining evidence of the operation are
remnants of the waste ponds, an office building and a garage structure. Dur ing the
summer of 1980, Montgomery County obtained soils from ~he United Creosoting site to be
used in improving local roads in a nearby subdivision. ,Soil. m~terial consisted of
surface soils and pond backfill from the Clark Distributing Company property. Citizens
living on one of the ."improved" street, complained of hea~~ch~s, burns, respiratory
problems and damage to vegetation. Samples indicated that soils were contaminated with
PCP in concentrations up to 20.3 mg/l. MOntgomery County officials removed the
contaminated soils from the affected roadways and disposed of them by landfarming. In
early December 1983, EPA initiated an immediate response action at United Creosoting,
tak ing ove r 25 soil samples. Samples indicated the presence of PCP, chlorinated dioxins
(no tetrachlorinated dioxins), and dibenzofurans. EPA ordered Clark Distributing to
(see Attached Sheet)
17. KEY WORDS AND DOCUMENT ANALYSIS
DESCRI'TORS b.IDENTIFIERS/OPEN ENDED TERMS C. COSA TI Field/Group
Record of Decision
united Creosoting Site, TX
Contaminated Media: soil, ground water
Key contaminants: PCP, PAH s, creosote
11. DISTRIBUTION STATEMENT 19. SECURITY CLASS (T/lis Rtport) 21. NO. OF PAGES
None 68
20. SECURITY CLASS (Tllis palt) 22. PRICE
None
I!'. ,."" 2220-1 (R... .-77)
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INSTRUCTIONS
,.
REPORT NUMBER
Insert Ihe lPA report number as it appeus on the cover of the publication.
LEAVE BLANK
2.
3.
RECIPIENTS ACCESSION NUMBER
Reserved for use by uch r.port recipient.
TITLE ANO SUBTITLE
Title should andicale dearly and briefly Ihe subjecl covera~ uf Ihe report. and be disl,lay,'d I,ruminenlly. s,.t ,uhlilk. Ifuse.1. m smali,'r
Iype or otherwise subordinale it 10 main litle. When a reporl is l1fep:ued in mon° Ihan ,'nc volume. r"",'allh,' I1rimary IIIle. a.ld y,.I:.anw
number and inc:1ude subtitle for Ihe speciflc title.
4.
5.
REPORT DATE
Each report shaU cury a date indicatinl at least monlh" and year. Indicale Ihe hasis ou whid. il "as ",,'le,'I,'d (qt.. Jail' oJ ;mtl'. Jil/l'Oj'
ilpprove/, dIIr, of p"ptlrtlrion, 're.).
PERFORMING ORGANIZATION CODE
Leave blank.
8.
7.
AUTHORISI
Give namelsl in clJnventional order (John R. [)(N. J. Ro/x'" Doc', ,'/('.). List authur's aniliallun if il ,lil"'ers hlllllll,,' l'Crfllrlllinit ..'itani.
zation.
..
PERFORMING ORGANIZATION REPORT NUMBER
In.. if performinl orpnization wIshes to ani", Ihis number.
I.
PERFORMING ORGANIZATION NAME AND ADDRESS
Give name. street. city. state. and ZIP code. List no more lhan IwO levels of an urganilal iunal hireardlY.
10. PROGRAM ELEMENT NUM8ER
Use the propam element number under which the report was prepared. Subor\Jinate numbcr, 11101)' he indud,',lm l'ar""lh,'",,,
11. CONTRACT/GRANT NUMBER
Insert contract or pant number under which report was prepared.
,.
12. SPONSORING AGENCV NAME AND ADDREsa
Include ZIP code.
13. TYPE OF REPORT AND PERIOD COVERED
Indicate interim final. etC'.. and if applicable. dates covered.
. - . t-'.
14. SPONSORING AGkNCV COOE
Insert appropriate code.
15. SUP'UMENTARV NOTES
Enter information not inc:1uded elsewhere but useful. such all:
To be published in. Supersedes. Supplements. "tc. .
1.. A.TRACT . I :', ,:. , " ". " ,".' . ; . ,", . -- - ,-.
Inc:1ude a brief (200 word! QI' len) fa~t\lll summary o( the mosl si~nili~ant .nf~rmali()n ,ulltain,..1 i,; II;,' "'"lIil. II II... "'1'<1'1 '"lIlalll' a
significant bibliopaphy or litenture survey. mention it here.
Prepared ill cooperation wllh. I'r,!nslallllll III". l'rc","I,'\I OIl "lInl""'II"" "'"
17. KEV WORDS AND DOCUMENT ANAL VSIS
(a) DESCRIPTORS. Selecl from the Thesaurus of i::nainl.ocrin. and Scienlific Term~ Ihe pruper aUlhori,,'d t"IIII~ IhalltJenlll'y Ihe majnr
concept of the research and are sufficiently speeit1c and precis..: 10 be us..:\J a~ IntJex entries lur calalut:1n~,
(b) IDENTIFIERS AND OPEN.ENDED TERMS. Use identificrs for project nilnll.~. t:ude namcs. cl!ulpmcnt 1.I..'Ij:nalors. dc. U", nllen.
ended terms wrinen in desc:riptor form for those subjects for which no dI:!I<:rlptor e>.ists.
(c) COSA TlI-1I-:LD GROUP. Field and poup aw.nments are to be taken from the 1965 C05"TI Suhi"cl Calq!nry Ust. Sinc,' Ihe mOl'
jority of documents are multidisc:iplinary in naturc. the Primary Held/Group assilnmcntf' I will be 'IIC'II j,' di" Iplinc. area ul' human
endeavor. or type of physical object. The applicationCs) will be cro~.rc"crcnce\J with Sl:n>ndary I ,,'hl/( ;111111' a "I!! II IIIC II Is Ihal \A'llIlulln\A
the primuy postinICS).
18. DISTRIBUTION STATEMENT
Denote releasability 10 the public or linut3tion for reasons ulher than sccurily fur e"amrh.: "Relea'c 1:111111111""'" ('tic all)! ~~;ul"l"hly 'n
the public. wtth address and price,
11." 20. SECURITY CLASSIFICATION
DO NOT submit classified reports to Ihe National Technicillinformatiun Sl:rvice.
21. NUMBER OF PAGES
Insert the total number of pages. including this one and unnumbered paacs. but exdu\Je 1.I1,llIbuliun 18'1. II any.
22. PRICI
Insert the price set by the National fechnicallnformation Service ur the Government Printing Office. If knuwn.
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EPA/ROD/R06-86/014
united Creosoting Site, TX
16.
ABSTRACT (continued)
undertake an immediate response action within the area of the former waste
ponds. Work began in November 1983 and consisted of regrading exposed
contaminated soils to divert surface water drainage away from the
subdivision, capping contaminated soils with a synthetic membrane cap and 6
inches of compacted clay, fencing the capped area, and constructing drainage
ditches to channel cap area runoff to the south of the Clark property
(vacant land). work on this activity was completed in April 1984, and the
RI/FS for the whole site area was begun in December of 1984.
The selected remedial action for the site includes: purchase and
demolish six homes located directly above and adjacent to the former pond
area, conduct permanent relocations of the persons currently residing in
these homes, consolidate surface soils contaminated with greater than 100
ppm of polynuclear aromatic hydrocarbons (PAHS) and surface soils which are
visibly contaminated onto the former waste pond area, construct a temporary
cap over consolidated soils, periodically evaluate the availability of
offsite disposal facilities and emerging alternate technologies, excavate
and dispose of the soils contaminated with greater than 100 ppm of PAHs in
the former pond area and in the former storage tank area when an appropriate
facility or innovative technology becomes available, backfill excavated
areas and restore ground surface with an appropriate cover, and allow ground
water attenuation through natural processes of dilution and adsorption. The
estimated capital costs of the remedy range from $4.5 million for future
offsite land disposal to $140 million for offsite incineration. Factors
such as site preparation, material and energy requirements, and disposal
requirements must be evaluated before a cost estimate can be developed.
Annual O&M costs are expected to be $43,000 during the interim closure
period.
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RECORD OF DECISION
REMEDIAL ALTERNATIVE SELECTION
Site:
United Creosoting Company, Hilbig Road, Conroe, Texas
DOCUMENTS REVIEWED
I have reviewed the following documents describing the analysis of the
cost-effectiveness of the remedial alternatives for the United Creosoting
Company site:
- Site investigation, United Creosoting Company, Roy F. Weston, Inc.,
December 1985.
)
- Feasibility Study, United Creosoting Company, Roy F. Weston, Inc.,
May 1986.
- Summary of Remedial Alternative Selection, United Creosoting Company,
September 1986.
- Responsiveness Summary, September 1986.
- Staff summaries and recommendations.
DESCRIPTION OF SELECTED REMEDY
- Purchase and demolish six houses located directly above and adjacent
to the former pond area.
- Conduct perma"nent relocation"s of the"persons currently residing in
these houses.
..;
. .:,.:
- Consolidate surface soils contaminated with greater than 100 ppm of
polynuclear aromatic hydrocarbons and surface soils which are visibly
stained onto the former waste pond area.
- Construct a temporary cap over consolidated soils.
- Periodically evaluate the availability of offsite disposal facilities
and emerging alternate technologies.
- Excavate and dispose of the soils contaminated with greater than
100 ppm of PAHs in the former pond area and in the former storage tank
area when an appropriate facility or innovative t~chnology becomes
avai labl e.
- Backfill excavated areas and restore ground surface with an appropriate
cover.
- Groundwater attenuation through natural processes of dilution
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DECLARATION
Consistent with the Comprehensive Environmental Response, Compensation,
and Liability Act of 1980 (CERCLA) and the National Contingency Plan
(40 CFR Part 300), I have determined that the selected alternative for
the United Creosoting Company site is a cost-effective remedy and
provides adequate protection of public health. welfare, and the environment.
The State of Texas has been consulted and agrees with the approved
remedy. In addition, the action will require future operation and
maintenance activities to ensure the continued effectiveness of the
remedy. These activities are considered part of the approved action,
and eligible for Trust Fund monies for a period up to one year. I have
also determined that the action being taken is appropriate when balanced
against the availability of Trust Fund monies for use at other sites.
{il {) Iff
(v?-n~O ~
ntrancesf . Phillfps
Acting Regional Administrator
~ . I .
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Summary of Remedial Alternative Selection
United Creosoting Company
Conroe, Texas
BACKGROUND
The United Creosoting Company site is an abandoned wood preserving
facility over which two new businesses and a residential subdivision have
been built. Formed lumber, such as telephone poles and railroad t1es,
were treated by the pressurized addition of creosote and pentachlorophenol
(PCP). The site was abandoned in 1972. The only remaining evidence
of the former wood preserving operations are the remnants of two waste
ponds, an office building, and a garage structure.
Site Location and Description
The United Creosoting Company site is a 100 acre tract located in the
City of Conroe, Montgomery County, Texas (Figure 1). The site is 1/4
mile southwest of the intersection of Loop 336 and the Missouri-Pacific
Railroad. The United Creosoting Company property is bound on the west
and south by Alligator Creek, on the north by Dolores Street and on the
east by the Missouri-Pacific rail lines. The site is now occupied by
the Clarke Distributing Company, Conroe Construction Company, and the
Tanglewood East subdivision (Figure 2). '..
The physical characteristics of the site have been locally altered by
the redevelopment of the property, which has resulted in residential
and light industrial structures typical of suburban northern Conroe.
Other residential areas surround the site to the -immediate north, west
and south, while industrial and commer.cfa,tl.and.:uses~-are evident to the
east.
Approximately 13,000 people curren.tly .1ive.,withina 2-mile radius of
the site, and rapid population gafns"areexpicted to-continue in Conroe
through the year 2000.
SITE HISTORY
The United Creosoting Company operated from 1946 to 1972. The wood
preserving plant site, prior to salvage and removal operations, contained
a coal-tar distillation still, a processing building, tanks and pressure
cylinders, two waste ponds, and several areas where treated lumber was
stored. Figure 3 depicts the estimated location of the processing
facilities based on a review of historical aeria1 photographs. The two
waste ponds were used by United Creosoting for disposal and possible
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- lite LocatIon
- Let 308 20' 00' N
Long: 858 27' 30" W
Source; USGS 7.5 minut8 88ri81 toCIOIraohic map
Conroe. TX Quadrangl.. '871
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FIGURE
. LOCATION MAP OF UNITED CREOSOTING
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The United Creosoting site has been the subject of continuous investigation
in recent years. In February 1970, the Texas Department of Water
Resources (TDWR) conducted a site investigation of United Creosoting and
found no discharge of wastewater from the site. In 1977. TDWR inspected the
site and reported that the former waste ponds were being backfilled.
Redevelopment of the site had begun at this time.
During the summer of 1980, Montgomery County obtained soils from the
United Creosoting site for improvements to Metts Road. Mockingbird Lane.
and various roads in the Lake Conroe Forest Subdivision. These soils
consisted of surface soils and pond backfill from the Clarke Distributing
property. Citizens living along Metts Road complained of headaches,'
burns, respiratory problems, and damage to vegetation. Samples were
collected from the roads and several locations on the Clark Distributing
Company property. Analysis of leachate from these soils indicated
pentachlorophenol concentrations up to 20.3 mg/l. Montgomery County
officials removed the contaminated soils from the affected roadways and
disposed of the soils by landfarm treatment.
In August 1982. TDWR installed three monitoring wells on site. Additional
wells were installed by the EPA Region VI Field Investigation Team
(FIT) and the National Center for Groundwater Research (NCGR) in 1982
and 1983. Analytical results of samples t'ake'n from these wells indi-cate that
polynuclear aromatic hydrocarbons and pentachlorophenol contamination was
present in the uppermost water bearing zone. I
" I
TDWR submitted the United Creosoting site as a candidate for cleanup under
the Superfund program in August 1982. The immediate concern at that time
was contaminated surface water runoff flowing from the former waste ponds
area into 'fanglewodi"EKst-Subdh'i:s!ion. The TDWR collected additional soil.
water and air samples from the site during the remainder of 1982 and into
early 1983. In September 1983 the United Creosoting site was included on
the pr~posed NPL by EPA and thus became eligible for remedial funding.
In early December 1983. EPA initiated an immediate response action at
United Creosoting. Twenty-five surficial soils samples were taken in the
vicinity of the former waste ponds and within the Tanglewood East subdivision.
The soils were found to be contaminated with pentachlorophenol and chlorinated
dioxins and dibenzofurans. No tetrachlorinated dioxins were identified at
the site. It was suspected that the source of the contamination might be
storm water runoff from former waste pond areas located on Clarke
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..
3
)
Based on the sampling results, Clark Distributing was directed under the
terms of an EPA Administrative Order on Consent to undertake an immediate
response action within the area of the former waste ponds. The action
regraded exposed sections of contaminated soils so that surface water
drainage was diverted away from the subdivision, capped areas of contaminated
soil with a synthetic membrane and at least 6 inches of compacted clay,
restricted access to the cap area by the addition of 200 feet of fence,
and constructed drainage ditches to channel cap area runoff to the south
through Clarke-owned vacant land. The action began in November 1983 and
was completed in April 1984.
A Cooperative Agreement for a Remedial Investigation and Feasibility Study
(RIfFS) was awarded to the State of Texas in March 1984. Roy F. Weston,
Inc., was contracted to conduct the RIfFS. Field work for the RI was conducted
in two phases, the first in December 1984 and the second in August 1985.
The data generated was used to estimate the extent and magnitude of
contamination and to evaluate the alternatives developed in the feasibi1ty
study. The total cost of the project to date has been approximately $1.1
million.
CURRENT SITE STATUS
The United Creosoting Company site investi~tion" consisted of surficial
soil sampling, soil borings, lagoon borings, trenching, groundwater
sampling, sediment sampling, stonmwaterfsurface water sampling, and air
monitoring. A geophysical survey was used to better define the location
and volume of the former waste ponds. The investigation. focused on the
identification of the geologic and hydrologi~ ch~racteristics of the
site, the extent" and magnitude of contamination' from the site, the target
receptors,'and population at risk.
Regional Geology and Surface Soils
The Un1ted Creosoting Company site is geologically situated in the West
Gulf Coastal Plain physiographic province of Texas. The coastal plain
is generally characterized by flat to gently rolling uplands with mud
and sand substrata. In the vicinity of the site, the topography
comprises gently rolling uplands and the natural vegetation consists of
forest.
Regional 50115 maps prepared by the USDA Soil Conservation Service
indicate that the natural soils in the area consist of the Conroe
Association. Specifically, the natural soils at the site consist of
the Conroe and Splendora series.' These soils range from gravelly loam
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4
moderate available water capacity. As a result of industrial and
residential development, much of the natural soils in the vicinity of
the site have been disturbed or covered by fill material and various'
structures.
A generalized geologic map of Montgomery County is presented in Figure 4.
As shown, the site is underlain by unconsolidated sediments (sand, gravels,
and clay) in alluvial fan deposits. These deposits are of P1eistQCene Age
(3 million to 20 thousand years old), and were formed by high-gradient
braided streams that flowed coastward from uplands to the north.
Stratigraphic information relative to the coastal plain of Texas is presented
in Table 1. Alluvium, the Beaumont Clay, the Montgomery Formation and the
Bentley Formation are not found at the United Creosoting Company site. The
surficial sediments at the site belong to the Willis Sand (Formation), the
coarsest of the Pleistocene Formations.
The Willis Formation consists largely of clayey sand and gravel and some
localized clay beds. The gravel is fairly coarse, is uniformly sandy,
and contains much fossilized or petrified wood. The Willis Fonmation
dips toward the Gulf at about 10 feet per mile and, in the vicinity of
the site, is estimated to be approximately 70 feet thick. The approximate
e 1 evat i on of the t~~of the Wi 11; s Form~t j.9n at the Un 7 ted Creo~9t i ng
Company site is 230, feet MSL. '-' "", ..~: T, '., ',,' ,
. '. .' .
Underlying the Willis Formation are the Go1iad Sand (Pliocene Age), Fleming
Formation (Miocene Age), Catahou1a.San~stonetMio~ene~ge} and the Jackson
Group (sandstone and ~la~:lI\embers: Qf the EQcen~ ~ge)" r "The thi ckne,ss of, , ,
these sed imen~s . a~ov~ t~e toP. Qf IJh~ ~ Jackson Grqup is, appro.xim~te ly: 3,600
feet in the V1c1n1ty of ~he s1te.
Regional Hydrogeology,
Groundwater is the major source of public and industrial water supplies in
Montgomery County, Texas. Three aquifers furnish the groundwater used in
the County. In order of increasing depth these aquifers are: the Chicot
Aquifer, the Evangeline Aquifer, and the upper part of the Jasper
Aquifer. The Burkeville Aquiclude, a massive clay layer, hydraulically
separates the upper part of the Jasper Aquifer from the Evangeline.
The majority of the groundwater is pumped from the Evangeline and upper
Jasper Aquifers. Lesser amounts of groundwater are pumped from several
low volume wells present in the Chicot Aquifer in Montgomery County,
some of which are in the immediate vicinity in the United Creosoting
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:
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Site
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FIGURE 4 GENERALIZED GEOLOGIC MAP FOR
MONTGOMERY COUNTY. TEXAS
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. .
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stratigraphic ,and Hydrogeologic Framework
Coastal plain of Texas
of
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-------
.
5
The sands of the Evangeline and Chicot Aquifers and the upper 300 feet of
the Jasper Aquifer contain fresh water in the Conroe area. lower sands of
the Jasper Aquifer contain saline waters. Figure 5 illustrates the occurrence
and thickness of the aquifers. These aquifers. as well as the Burkeville
Aquiclude beneath the Evangeline. are described below:
o Chi cot Aquifer - The Chi cot is the youngest aquifer in the
coastal plain of Texas and is continuous in the souther~ part
of Montgomery County. These formations are composed of unconsolidated
reddish sands and gravels. often ferruginous. In the Con roe area.
the aquifer consists of the Willis Sand. Water from the Chicot is
generally soft and fresh. The pH ranges from 5.0 to 7.5 and the
concentration of dissolved solids ranges from 36 to 268 mg/l.
The average permeability of the Chicot Aquifer in Montgomery County
approaches that of the Aquifer in Harris County. which is 500
gallons per day (gpd) per square foot. Based on this permeability
value the average transmissivity of the aquifer is estimated to be
25.000 gpd per foot.
Water levels in the Chi cot Aquifer fluctuate in response to recharge
from precipitation and unlike the deeper aquifers. the water levels
have not exhibited any long-term decreasing trend. The flow gradient
in the aquifer is generally southward at a hydraulic gradient
of approximately 4 feet per mile.
"
..Il
o ~~a:~~~~ n~ n A~~~:~~m;r;h~o~~~~9~~~~:c:~f~ ~:'~ ~;~h=e~~~~~~ s~~r~~ ternat i ng
sand~ and...clays"of the Goliad Sand and part of the Fleming Formation
above the Burkevil1e Aquiclude. Analyses of water from wells in
the Evangeline. indicate that water in this unit is generally fresh
and hard. ' Dhs'ofved sol ids concentrations range from 250 to 400
mg/l. The pH of the water ranges from 5.5 to 8.2.
It is estimated that the average permeability of the Evangeline
Aquifer in Montgomery County is 250 gpd per square foot. and
the estimate of average transmissivity is 50.000 gpd per foot.
Due to increased withdrawals over the past decade water levels
have declined in wells completed in the Evangeline Aquifer by
as much as 10 to 25 feet in the Conroe area. The groundwater
flow direction in the Evangeline is generally southward at a
-------
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. Appro"""" Loc8IIan 08 Unled Cf8OIOIIng Co. SIt.
C'
FIGURE 5 ~- ITRA TIGRAPHIC'-AND' HYDROGEOLOGIC 8eCTION
MONTGOMERY COUNTY, TEXA8
.'
40li
lOll
...
....1
zod
«10'
fIJd
wad
rood!
lzod
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-------
-
,
6
The Burkevi11e Aquiclude - The Burkevi11e Aquiclude is a massive
clay with thin interbeds of sands and silty sands. This unit
forms a low permeability confining system which separates the
Evangeline Aquifer from the upper part of the Jasper Aquifer. The
Burkevi11e is not a source of groundwater except for small wells
developed in a few areas where the interbeds of sands supply fresh
water in small quantities.
Site Hydrogeology
o
The following hydrogeologic information on the United Creosoting site and
the immediate area has been compiled from records of existing area wells
and localized subsurface data gathered during remedial investigation activities
of December 1984 (Phase 1) and August 1985 (Phase 2).
Drilling logs of selected Montgomery County water wells registered with
the Texas Water Commission were reviewed in detail in order to identify
those wells possibly impacted by the United Creosoting site. The wells
reviewed are located in the TWC well-numbering system 2-1/2 minute quad-
rangles TS-60-45-4 and TS-60-45-5. These quadrangles contain the site and
any reported wells which may be installed in downgradient strata within 2
miles of the site.
Data from these records show frequent use of both the Evangeline and Chicot
aquifers in the Conr,oe area. .At least 60 wells have been reported within
the Chicot and Evangeline aquifers up to two miles downgradient from the
site. The locations of these wells are shown in figure 6. It is possible
that a greater number of groundwater wells are installed within two miles
downgradient of the site, and that these wells have not been reported to
the Texas Water Commission. However, high volume, multiple user wells such
as the City of Con roe municipal supply wells are generally screened in the
deeper Evangeline sand and single-user wells are found in the shallow
Chfcot formation.
The site hydrogeology, schematically shown in figure 7, is characterized by
two water bearing zones separated by a clay aquitard. The thickness of
this aquftard ranges from 22 to 32 feet.
The shallow water bearing zone (1125-foot sand") is comprised of two
interconnected sand lenses separated intermittently by a thin clay layer.
The upper, unconfined lens begins at a depth of 14 to 44 feet below the
ground surface and averages approximately 10 feet thick. The average
groundwater velocity in this lens is estimated to be 5 to 10 feet/year in a
southern direction. The lower, semi-confined lens begins at a depth of 26
feet. The average groundwater velocity in this lens is estimated to be 5-
-------
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o
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. LEGEND:
C'aRT 81L0W 8UaFACIJ
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~..... I -./ ,\ ,
. '-'-- .... .
FIGURE
-------
":--.'~'!~JJ
~.."--- .
_M
- .,
. .
IURFIC..L CLAY LAYER
SHALLOW UNCONF~D
WATER BEAR." ZONE ItAt
-----------
'.
T"',LOCALIZED CLAY
----------
SHALLOW SE~DNFWED
WATER BEAR"G ZONE' IIBt
CONTllUOUS CLAY LAYER
LOWER
WATER BEAR.,G ZONE
BASAL CLAY LAYER
LEGEND
,. TO -- .....0 'AID
IOMETIM£' wnltAc£ CLAY
:::=J
..
CU'Y WITH MIlD ... I" ITItIIIPt
tcM(M.TIC ..... """ 1PP'ItO....TI
ICII(f8l[O ..nAVAl. -IMALLOW
WlCONF~ 1081[; 88-SHALLOW SI..
COWIIID ZONI; t-LOWllt W"'P KUlIG
1081[ I
i
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, .
121
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t'
SWI
DWI
SWIO DWIO
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"TM-SOUTH LD110N OF 'DItMIR
',wasT( PONDS
NOr 1'0 SCAlE
...
DIRECTION OF D08ANT MOUIIO-
'WATEIt FLOW TMltDUGH WATEA .......
SAND ZONES
PlGUM
'I
UNmD CltlOIOThIG 'IAltllL," 8TUDY
8CHI!MATIC CROnll!C11OII OF _AIt
8U88UItFAca NYDltOGIOLOGIC .....,1
-------
7
The shallow water bearing zone is characterized by an extremely low yield
and use of this zone as a domestic water resource is not anticipated.
Below the shallow water bearing zone is a clay layer, averaging 30 feet
thick. The permeability of this layer is approximately 10-5 feet/day,
indicative of clays which can retard vertical migration.
The second water bearing zone exists at an approximate depth of 56,to 84
feet below the ground surface. The zone is approximately 20 feet thick
and groundwater movement is estimated to be 5 to 15 feet/year toward the
south. .
The potential for vertical migration of contaminants from the 25-foot to
the lower water bearing zone was evaluated in the RI. Based on the
permeability of the aquitard and the hydraulic gradient between the two
zones, two conclusions can be drawn:
o
There is low potential for downward vertical flow from the
shallow water bearing zone to the lower water bearing zone.
However, due to sands lenses, thin interconnected sand stringers,
and slickensided surfaces in the aquitard, some areas below
the site may show more accelerated vertical migration rates.
. .
.,
"... ' I..
-
o Based on the calculated- vi!rtical flow velocity and the
thicknes.s, of .the confining clay, groundwater pene.trat.ion of the
clay is not expected for at least 100 years.
-"-':1' ,
. , ~ ! t I; . .'
Surface Water Flow,~nd Sit~ Drainage
, . ,.
The United Creosoting site is located east of Alligator Creek and
is sit~ated wholly within the watershed of Alligator Creek. Alligator
Creek, which skirts the southwestern portion of the site, eventually
flows into the West Fork San Jacinto River.
Site surface water drainage enters Alligator Creek at various locations on
and off the United Creosoting site. The overall site surface water drainage
flow is toward the south, although patterns on much of the site have been
altered by development. The subdivision properties drain into the streets
of Tanglewood East, and then, into Alligator Creek at culverts on Lilly
Boulevard and Hancock Street. Con roe Construction property runoff flows
mainly to the west and then into the subdivision drainage system at Arlington
Street. Clarke Distributing properties drain to the s9uth and into a ditch
which feeds Alligator Creek as shown in Figure 8. The cap area over the
former waste ponds drains into this ditch, and runoff from paved areas is
forcd into the ditch by curbing. There is minimal runoff from Clarke
Distributing into the drainage ditch that runs the length of the site, just
west of the Missouri-Pacific Railroad. This railroad ditch and the vacant
area drainage ditch do not interact.
.
-------
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-------
-
8
EXTENT AND MAGNITUDE OF CONTAMINATION
Data from the remedial investigation indicates the presence of contamination
from creosoting compounds and PCP in surficial and subsurface soils and shallow
ground~aters at the United Creosoting site. The remedial investigation
activities. combined with a review of the site history. resulted in the
definition of the following areas of contamination at the site:
)
o
Subsurface (3 to 25 foot deep) soil contamination in the area of
the former waste ponds and an area formerly occupied by a tank
farm.
o
Surficial (ground level to 3 feet deep) soil contamination in
areas of the site visually marked by an accumulation of asphaltic
wastes ("tar mats"). thin crust material. darkened soils. or
stressed vegetation and. in areas of surficial water runoff including
a 1 arge previ ous1y "swampy" area south and west of the former
waste ponds.
o
Shallow groundwater .contamination in two interconnected water
beari n9 strata found. from about .15 ,to about..'SO fe~t below ground
surface.
. -.j " p ,'"-- i".
Significant contamination of air. stormwater runoff. surface waters or
sediments of A11igatp~.Cre~~JJQ.~ groundwaters. households. or structures
was not detected durin9t~~..~~edial investigation.
The areal extent of s~i~r ~MIO~hal)..ow groundwater cont~mination. is summa~ized
in Figure 9. These. ~~~1~~~~~~~r~~1y~q~p~y~1~Te,~whlCh contaln contamlnants
in excess of levels P9~1~~.. lmpactlnglnumanneaTth (as recommended by the
Centers for Di sease Con\rp 1r,.) , ,. .r- I \\ '.)- ;1:C::' .,n
..~ '" i)~'''; I ~YI ,'~~.~~l..)'b,;,~n f~': . t. .t"I~.JV-=. t"f -.
Vo 1 urnes. of soi 1 and groundwa.te.r contami nated above the CDC gu'fde 1 i nes are
estimated to be: .
o
13.000 ~~bic yards of waste pond materials;
27.000 cubic yards of contaminated soils below and adjacent to
the former waste ponds;
o
o
20.000 cubic yards of contaminated residential surficial soils;
9.500 cubic yards of contaminated industrial surficial soils.
o
o
13.000.000 gallons of contaminated shallow unconfined groundwaters;
and
o
-------
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Cont
-------
.
9
A smaller volume of contaminated shallow groundwater was identified
during development of the feasibility study. This volume. 7.000.000 gallons.
is comprised of groundwater contaminated with greater than 21 ug/l of
pentachlorophenol. This concentration of PCP was identified as an EPA Health
Advisory at the beginning of the feasibility study. During the course of the
study. EPA developed a less stringent advisory level of 1.05 mg/l. The
latter concentration was considered in the evaluation of the groundwater
alternatives.
Chlorinated Dioxins and Dibenzofurans
Chlorinated dibenzodioxins and polychlorinated dibenzofurans are known
to occur as impurities during the manufacture of pentachlorophenol (PCP).
Since the United Creosoting Company was known to use PCP in its wood-preserving
operations. selected soil samples from the site were analyzed for the
these compounds. Samples were specifically analyzed for the highly toxic
and strictly regulated 2.3.7.8 - tetradioxin isomer. It was notl.detected
at the site. and is not expected to be found in wood preserving wastes. '
However. other chlorinated dioxin and furan isomers. were detected in areas
of surficial and subsurface soils where polynuclear aromatic hydrocarbons
(PAHs) and PCP were also found.- ',' 'I ~':."' ':; L
~'.':~\'r.r~
The threat to human health posed by chlorinate
-------
.
10
The data collected at the United Creosoting site supports the following
concerns:
)
o
Temporary releases of volatile organic compounds are probable
during any disturbances within areas of extensive subsurface
contami nat i on;
o
Shallow groundwaters in the site vicinity have been contaminated
with semi-volatile organic compounds. About 43,000,000 gallons of
groundwater, present in two interconnected shallow zones, ,are
contaminated in excess of background concentrations;
Lower groundwater quality is currently unaffected by the
contaminants from the United Creosoting Company;
o
o
Surficial soil contamination is evident across the site. Localized
areas are contaminated to an extent which may impact human
health by direct contact with soils;
o
Extensive subsurface soil contamination is present in the area
of the former waste ponds and below the former tank farm and
coal tar distillation unit. These soils continue to impact
groundwater quality. Concentrations 9f pentachlorophenol and
polynuclear aromatics were the highest 'found on-site and far
exceed re~omm~nded cri teria for: the pro~ect i on of human hea.l th;
II~r.J'JA, . J>~':,...,..~;.~ ..;...",~t "'1')"."" .~
Detectable contamination is not pre.sent'.1n Tangl'e~~~d!", E~st h'oirt~st~nd
Vegetation on-sjtehas been visibly stressed. This stre~s may
be due to' c6mm1iiat i on at thes'1 tea'ncWcir tlie disturbances cau'sed-
by si'te 'de~efo~~nt. '- >" . .. ". '.,~' ,-..-",~
.. .~ . " J-.- I'll ~ '111': r ~ '~j)'!
o
o
Air
CONTAMINANT MIGRATION PATHWAYS
1 1 .' . \"o-'.t ~
. ~ I I'
" .
'. ..,
Monitoring during the remedial investigation indicated that PAHs are not
currently affecting air quality and do not pose an immediate threat to
the public. However, any significant disturbance of the site or lack of
maintenance of a protective cover could cause future air quality degradation
in the vicinity of the site.
Surface Water and Site Runoff
Contamination was not detected in any of the sto~ water runoff samples.
These results seem to indicate that the Immediate Action undertaken in
-------
.
~
11
successful in halting the migration of contaminants from the former waste
pond area in this manner. While storm water runoff is not currently
contributing to significant contaminant migration. future problems may
arise due to a lack of maintenance of caps over the former pond and tank
farm areas.
Groundwater
The primary route of contaminant migration at United Creosoting is via the
25-foot water bearing zone. The groundwater in this zone is moving
horizontally at a rate of 10 to 15 feet per year. Because PAHs and PCP
exhibit low mobility and a tendency to adsorb onto soil. the contaminant
plume can be expected to migrate at a slower rate. As stated previously,
the aquitard below this water bearing zone is expected to be an adequate
barrier to vertical migration of the contaminants.
As a result of removing or isolating the source of contamination to the
groundwater (the pond area) by a remedial action. natural attenuation of
the plume would be expected. Dilution, adsorption, and possible
biodegradation of the contaminants would result in a decrease in concentration
over time. This is discussed further in the "Groundwater Alternatives"
section of this Record.
Target Receptors
..":J'\' r
The following target receptors were identified in the remedial investigation:
- Persons disturbing the subsurface soil by excavation for property improvement;
and
- children playing in the area of the "asphaltic mats" in the residential
area.
Enforcement
During the course of an ongoing investigation. EPA has identified two
Potentially Responsible Parties (PRPs) for this site. Notice letters were
sent to all known PRPs in August 1986. PRPs have been given the opportunity
to participate in all actions that have been taken to date. Betweem December
1983 and March 1984, Clarke Distributing Company. in compliance with AO on
Consent issued by EPA, capped the former pond area and improved the
drainage away from the Tanglewood East residenti~l area.
Although no response have been received from the August 1986 notice letters,
the PRPs will be offered the opportunity to participate in the implementation
of the selected remedy. If negotiations are unsuccessful, it is recommended
that the cleanup be Fund financed, and appropriate enforcement action be
sought at a later date. Any additional PRPs identified will also be offered
-------
.
12
Current homeowners received notice letters indicating their status as
PRPs, since present policy dictates that current landowners be designated
as PRPs in order to acquire a release or access to the property in question.
In the event that access is denied, the Agency retains the option to initiate
cost recovery actions. However, access to the property has not been a
problem at this site, thereby precluding cost recovery actions sought
against the homeowners in the Tanglewood East Subdivision.
ALTERNATIVES EVALUATION
The Feasibility Study (FS) for United Creosoting was performed to determined
what actions, if any, would be appropriate as a permanent remedy. Several
alternative remedial methods were developed by Roy F. Weston, Inc. The
ultimate objective of the FS was to develop alternatives to adequately
protect public health and the environment from past and potential
releases of contaminants currently onsite.
The major threats to public health and the environment attributed to
the site are:
- Direct contamination of shallow groundwater by leaching from the
former pond and tank farm areas and possible future contamination of the
lower groundwater zones; ',. ,,;
future direct contact with subsurface soils from the pond and tank
farm areas due to excavation activities; and
- potential airborne transport of soils and volatile organic compounds
from the pond and storage areas.
Remedial Objectives
The overall objective of any remedy selected at any Superfund site is the
protection of human health and the environment. Objectives for specific
media at United Creosoting are listed in Table 2.
In accordance with the National Contingency Plan (NCP), the requirements
of Federal environmental regulations, guidances, and advisories are
appropriate in determining the extent of remedial action at a site. In
the absence of such standards, a risk assessment model should be used
to determine the extent of remedial action. No regulatory standards for
cleanup levels were identified for the contaminants at United Creosoting.
The remedial criteria developed for United Creosoting are presented in
Table 3. These criteria were developed from h~alth assessments guidance
provided by the Centers for Disease Control. Also taken into account were
the current land use (residential and commercial) and current and potential
use of the shallow water bearing zone (none). Documentation of the Centers'
-------
\)
~ABLE 2
SELECTED PLANNING OBJECTIVES
UNITED CREOSOTING COMPANY SITE
,
[[[
CONTAMINANT
PATHWAY
OBJECTIVE
[[[
CRITERIA
Groundwater -
Shallow Water
Bearing Zones
Groundwater-
Lower Water
Bearing Zones
Soi18 -
Surficial
.A
~
Soi18 -
Subsurface
Surface
Waters
Air
No further degradation
of shallow groundwater
quality on- and off-aite.
Prevent lower ground- .
water degradation.
Reduce contaminants to
prevent any acute or
chronic effects on
human health and
environment.
.' . ; ~,
. I
Reduce contaminants
to prevent any acute
or chronic impacts on
human bea1th and
en~ironment.
Prevent aurface .ater . .
degradation.
Prevent degradation
of air quality on-
or off-aite.
"
Shallow ground-
water contaminant
concentrations not
to ezceed current
measured condi-
tions
Kaintain lover
groundwater at
background levela
Reduce/isolate
high contaminant
concentrations to
levels protecting
human health and
the environment
Reduce/isolate
high contaminant
concentrations to
levels protecting
human health and
the environment
"ainta1n back-
ground surface
-------
.
'.
'1' ABLE 3
CRITERIA POR SITE CONTAMINANTS IN SOILS
'1'0 AVOID CHRONIC BUKAN HEALTH IMPACTS
RECOMMENDED BY CE~'TER FOR D1 SEASE CONTROL
UNITED CREOSOTING COMPANY SI'1'E
[[[
COMPOUND
CONCENTRATION
[[[
'lotal Polynuclear Aromatics
Pentachlorophenol
Sexa-Dioxin
Septa-DioxIn
. ':
100 mg/kg
150 .g/kg
1 ug/kg
5 ug!kg
25 ug/kg
1000 ug!kg
-------
.
13
The objectives and criteria are specific to United Creosoting and provide
the basis for identifying and evaluating possible remedial alternatives for
the site. A more complete discussion of the development of the remedial
objectives and criteria can be found in Section 3 of the Feasibility Study.
Identification and Screening of Technologies
~
The process by which potential remedial alternatives are developed and
evaluated is outlined in Section 300.68 of the NCP. The first step in
this process is the identification and screening of technologies that
may be applicable to the site conditions. Screening was done by applying
the following criteria:
- environmental effectiveness;
- cost; and
- technical feasibility and implementability.
Technologies which were judged incapable of satisfying the above criteria
were eliminated. A summary of the initial evaluation stage is presented
in Tables 4 and 5.
Detailed Evaluation of Alternatives
Alternatives retained from the initial screening, and the "No Action"
alternative were evaluated to assess their relative effectiveness in
protecting public health and the environment. The detailed evaluation included:
,>
- detailed' 'specifications; ,-~ ."'
- analyses of adverse envtronmental impacts;
- assessment of public health and environmental protection;
- detailed cost estimates, including operation and
maintenance and net present values; and
- schedules.
'.
Summaries of the results of the detailed evaluation of retained alternatives
are presented in Tables 6, 7, and 8. These alternatives were then narrowed
down to three groundwater remedial alternatives, five source control (soils)
alternatives, and the "No Action" alternative. Brief discussions of these
final alternatives are presented in the following sections of this Record.
Groundwater Alternatives
Fifteen different groundwater methods were developed and evaluated in the
feasibility study. Screening criteria for these methods included time
to complete the remedy and cost of the treatment technology used. A detailed
-------
~ ")
o
.
,
'fABLE
4
POTENTIAL REMEDIAL ACTION METHODS
DNITED CREOSOTING COMPANY SITE
.................e.........................................
SHALLOW GROUNDWATERS
o
Natural attenuation
Katural attenuation after .ource removal/isolation
o
o
Withdrawal with off-site disposal by:
- deep well injection
biological or physical/chemical treatment
- incineration
- soli~ification an~ landfill
With~rawal with on-site treatment an~
Treatment accomplished by:
- biological oxidation
- chemical oxidation/detoxification
activated carbon adsorption
- UV photolysis
incineration
- air stripping
0"
" "
Withdrawal with on-site treatment and
Treatment accompli~ed as noted above. "
discharge.
o
o
reinjection.
o
Withdrawal
an~ on-site storage
o
Plume containment bya
- barriers luch as slurry valls
- gradient control wells
In-situ treatment by:
- enhanced microbial degra~ation
- chemical injection
SURFICIAL AND SUBSURFACE SOILS "
o Excavation with off-site treatme~t/dispo.al by:
- incineration
- lan~fill
o
Excavation with interim storage by either I
- on-site facilities, or '.
-------
TABLE 4 (cont.)
POTENTIAL REMEDIAL ACTION METHODS
UNITED CREOSOTING COMPANY SITE
SURFICIAL AND SUBSURFACE SOILS fCont.)
o Excavation with on-site disposal by:
- RCRA compliant landfill
- waste encapsulation
o Excavation with on-site treatment by:
- incineration
- biological treatment
- solvent extraction
- DV photolysis
- chemical oxidation/detoxification
o On-site treatment followed' by on-site reburial of
residues or off-site disposal as non-hazardous waste
o Infiltration controls by:
- clay
- synthetic membrane
- coil admixtures
o In-situ treatment by:
- enhanced biological degradation
- soil aeration
- waste fixation/stabilization
- solvent extraction followed by groundwater recovery
o No action
SITE MANAGEMENT
o Grading
o Revegetation
o Surface water diversion
o Monitoring and maintenance
o Fencing
-------
.
!'ABLE S
ALTERNATIVE REMEDIAL ACTION METBODS
V~ITED CREOSOTING COMP~~ SITE
INITIAL SCREENING RESULTS - REJECTED METBODS
[[[
REJECTED METHODS
[[[
REASON POR REJECTION
SHALLOW GROUNDWATERS
o Withdrawal with on-
site treatment by:
-
tJV photolysis
air stripping
o
Withdrawal and on-
sitestorage
o
Plume containment by:
gradient control
veIls
o
In-situ treat..nt byz
-
chemical injection
~reatment technology required is
costly to operate and ~isplays
variable treatment efficiencies
necessitating an effluent polish-
ing step such as activated carbon
adsorption.
Contaminants present display low
volatil i ties, mak ing treatment
technically difficult. Environ-
.ental risk with air releases in
populated area.
Inconsistent with planning objec-
tives. Excessive costs ~ue to
time span required to iDlplement
withdrawal and .ize of storage
units.
Technically ineffective due to
slow-moving hydrogeology of .hal-
low water bearing aones.
. .
Contaminants present are resist-
-------
TABLE 5 (cent.)
ALTERNATIVE REMEDIAL ACTION METHODS
UNITED CREOSOTING COMPANY SITE
INITIAL SCREENING RESULTS - REJECTED METHODS
REJECTED METHODS REASON FOR REJECTION
SDRFICIAL AKD SUBSURFACE SOILS
o Excavation with interim
storage by:
- on-site facilities Inconsistent with planning objec-
tives. Excessive costs in compa-
rison to in-situ storage.
- off-site facilities No identified commercial storage
facility due to presence of
chlorinated dioxin. Excessive
costs.
o Excavation with on-site
treatment by:
- solvent extraction Required solvents also hazardous
and must be treated. Not a
method in itself.
-; UV photolysis Treatment technology is inconsis-
tent with waste pond materials.
Difficult to maintain feed
stream.
o Infiltration controls by:
- soils admixtures Inconsistent with planning objec-
tives. Difficult to implement
due to depth of contamination.
- synthetic membrane Not environmentally effective in
populated area. Nould also
-------
.
TABLE 5 (cant.)
ALTERNATIVE REMEDIAL ACTION METHODS
DNITED CREOSOTING COMPANY SITE
INITIAL SCREENING RESOLTS - REJECTED METHODS
REJECTED METHODS
[[[
[[[
REASON FOR REJECTION
SDRFICIAL AND SUBSDRFACE SOILS
o
In-situ treatment bY1
- enhancee biological
degradation
-
80il aeration
-
waste fixationl
8t.bilizatiqn:;
-
801vent extraction
followed by ground-
water recovery.
Not implementable. Applicable
to surface 80ils only. Contami-
nant concentrations In vaste
pones likely toxic to bacteria.
Silty clays hinder diffusion of
bacteria and nutrients through
8ite 80i18. By-products of
biological destruction may a180
be hazardous.
Contaminants present display low
volatilities making treatment
technically not feasible.
Inconsistent with planning objec-
tives. Difficult to implement
due to depth of contamination.
Required 801vents a180 hazardous
.and likely to adsorb onto 80i18.
-------
1
"
,
, (
SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
, UNITED CREOSOTING ,COMPANY
CONROE, TEXAS .
"
-------
SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
UNITED CREOSOTING COMPANY
CONROE. TEXAS
TABLE OF CONTENTS
)
Background
Site Hi story
Current Site Status
Extent and Magnitude of Contamination.
Contaminant Migration Pathways
Enforcement
f ~.:... I'
Alternatives Evaluation'
'\".
,"'";
J
Community Relations
Consistency with Environmental laws
Recommended Alternative
Operation and Maintenance
Schedule
...
1
1
3
8
10
11
12.
17
17
18
20
-------
. ... .-. '-' ... -
. .. ..- ~...~ .
/
TARt.E 6 ~
~IMB RBQUIRBMENTS POR SHALLOW GROUNDWATBR RE"EDIA~IOR
UNITED CREOSOTIRG COMPANY SITE
[[[-.......................................
THDRAWAL AREAl
URRY WALL AREA
~REATMENT/DJSPOSAL METHOD
INJECTION COMPONENT
I......~....................................~.~.....~...D.........................................
Itire Plume
Itire Plume
Off-Site Disposal
Off-site Disposal
On-site Treatment
On-Site Treatment
None
Inject to Enhance
Removal
None
Inject to Enhance
Removal, Discharge
Treated Waters
Reinject Treated
Groundwater
It I re Plume
Iti re Plume
Itlre PlUM
On-Site ~reat*ent
19hest Contamination
19hest Contamination
Lghest Contamination
Lghest Contamination
Off-Site Disposal
Off-site Disposal
On-Site Treatment
On-Site Treatment
None
Inject to Enhance
Removal
None
Inject to Enhance
Removal, Dishcarge
Treated Waters
Reinject Treated
Groundwater
19hest Conta81natlon .
On-Site Treatment
Lurry .all Around Slurry Wall None
Pond .Area
Lurry Wall Around Highest Slurry Wall None
Concentration Plume
) Action None None
APPROXIMATE NUMBER or
YEARS TO REACH
BACKGROUND QUALITY
150
20
150
20
20
Pump
AI..U
40
5
40
5
Rematnlne)
Plule..-
300
300
300
300
5
300
Pump Stag-
nation Point
\ 340
310
No Well
»400
»400
400
-------
.-. ...
.. ~ ..,...... .,~..-
... ...... - --,-,. .....
--
TABLE 7
8U1111ARY or REJIIEDIAL AcrIO" IIftHOD COS'f BS'lIJIIA'l'BS
O"IT£D CREOSOTING COMPANt SITS
i[[[
MBDIAL IIETHOD
'1'O'1'AL CAPITAL
. COS'l'
'l'OTAL PRES£N'l'
MONITORING AND MAINTENANCE.
ANNUAL PRESENT WORTH
[[[
ALLOW GROUNDWATERS
tural Attenuation
tire Plume Withdrawal With 1
f-Site Disposal by.
-Deep Well Injection
-Incineration
-Biological/Che8ical ~re8t.ent
-Solidification and Landfill
tire Plume Withdrawal Withl
-Site Treatment and Discharge.
eat.ent Accomplished by.
-Activated Carbon Ad8orption
tire Plume Withdrawal Withl
th Treat.ent and Reinjection.
!at.ent Acco.pllshed by.
-Activated Carbon Ad8orption
~hest Contaaination Plu8e2
thdrawal with Off-site
[)isposal by.
-Deep Well Injection
-Incineration
-Biological/Che.ical Treatment
-Solidification and Landfill
" ,:. $51,000
$ 6,000
$ 71,000
$ 120,000
. '.
'fy.
,'''rr:;..i, -'
t ~t.-:.
. .
,~l,OOO,O'OO
100:,O~O, 000
8S-t'OOO,000
1""-*(lOO;'OOQ
300,000
300,000
300,000
300,000
32,000,000
3,200,000
3,200,000
3,200,000
72,000,000
100,000,000
88,000,000
180,000,000
l"~rllPi'lt A~ .-or:-'
t"\fft ~1' .~, r
I If. : ',r f' (
'!':.~-"': J,,-'
J,
\' ,
"".."';:-':~ I'
,''''J~~,O.OO.
, , . ~. .
380,000
3,200,000
8,300,000
. ~':'Qo" I.
. .,1,
.;':rJ'n~ i-.U.\T
,4,500,000
380,000
3,200,000
7,700,000
'; 1-:-; :
,'. t.o
j.. . ,.~ - 1
....J: "..
:;
6,900,000
10,000,000
8,500,000
18,000,000
190,000
190,000
190,000
190,000
900,000
900,000
900,000
900,000
7,800,000
11,000,000
9,400,000
19,000,000
-------
TABLE 7 (cant.)
8tJf111ARY 0' REMEDIAL ACI'I018 "ETROD COS7 ES!'IMft8
UalTED CREOSOTIHG CO"PANY SITB
............................................e[[[
MBDIAL "ETROD
'fO'1'AL CAPITAL
COST-
MONITORING ARD "AINTEHANCI
ANNUAL PRESENT WORTH
'I'OTAL PRESBNT
WORTH
[[[---........................................
gbest Contamination Plu.e2
thdrawal with On-Site
Treatment and Discharge.
Treatment Accomplished by.
-Activated Carbon Adsorption
gbest Contamination PlU8e
thdrawal with On-Site
Treatment and Reinjection.
Treatment Accomplished by.
-Activated Carbon Adsorption
-Biological Activated Sludge
uae Containment by.
-Bentonite Clay slurry Walls
Around Former Waste Ponds
-Bentonite Clay Slurry Walls
Around-Highest Contamination
Plume Area
-,
'':f".. - i,.c I
!'~ 1 .
~',. '
l~.PO,:OOO
300,000
1,200,000
2,800,000
It". ,- .
"utllr~ h;
or-- a....~ ~ j . "
""~r"'! "
l..tl:
~ ......-".
$1.'$.0..000
5;"00',000
;t{'J.ar"-'": .
"1'':J.~, . .
~J'J; poq
: r': - "'.". ~J' :-
l~g~"oo '.
240,000 1,200,000 2,700,000
800,000 3,100,000 8,900,000
2,500 190,000 980,000
21,000 300,000 1,500,000
:tIl' .......,
tn'tt,?" : ';'1;
RPICIAL AND SUBSURPACK SOILS
cavation with Off-Site Treat8ent/
Disposal bya 3
-Incinera~ion
-Landfill
~~ ;. h. . ,-
'.,t, ':,' '
~rr.1 ,
"L~. ..- (,
C" .:
.. i" ~ .', f. j .~ - L'
fi err',r, .. "'1 . .... ~ . ; - 1". : ,r.' ...-:
140,000,000
24,1I!t8,~00
--
--
140,000,000
24,000,000
--
--
"'l~.., .
cavation with On-Site DisP08al by.
-RCRA Co.pliant Landfill
~11l ~ . . - .
" J "
8;100,000
':::::B~';' ,
15,000
800,000
9,700,000
Highest contamination pluMe withdrawal ..thods include aft injection c08Ponent to reduce remedia-
-------
-. . to . -.-., .., ...
t. ;".' ~
. .. -... .
-
TABLE 7 (cant.)
BmlflARY 0' REMEDIAL AC'l'ION ME'l'IIOD COft IS'I'IRA'!'!S
URI'!'ED CRBOSOTING COMPANY SI~I
I............................................~~...~~.~~.........................................
IJ'O'J.'AL CAPI'l'AL MONITORING AND MAINTENANCE ... 'l'OTAL PRESENT
:DIAL MB'J.'HOD COSl' ANNUAL PRESENT NORTH WORTH
I..............................................~~...............................................
:....- r ..
.yation with On-Site '1'reat.ent
:d Reburial. 'l'reat-.nt
!collplished by. 17,0'0,000 .
ncineration -- 8,000,000 25,000,000
,and Farllling 12,088,000 -- -- 12,000,000
oiological Slurry 13,0'8;000. -- 200,000 13,000,000
he.ieal Oxidation 84,000,'000 -- 25,000,000 110,000,000
e Encapsulation by.
lay Cap and Slurry Walls in
orller Waste Ponds and 'l'ank
arll Areas 2"00,000 54,000 150,000 3,100,000
lay Cap and Slurry Walls after
ran8fer of 'l'ank Far. 80ils to
aste Ponds 3,400,000 54,000 100,000 4,000,000
Itration Controls by.
lay Cap In For8er wast. 'onds 2,100,000 43,000 4'0,000
nd 'l'ank Far. Areas 2,100,000
lay Cap after ~ransfer of 2,100,000 43,000 510,000
ank Far. Soi18 to Waste Ponds 3,100,000
rl. Capping Followed by Excavation 25,000,000 43,000 230,0'00
d Off-Site Disposal In Landfill 25,000,000
ction 51,000 4',000 70,000 120,000
[[[
-------
... .., - .. - .. ~ ..
TABLE 8
NIfEIRP4'IV8 mHllAL 1Ct10M te'IIDS Df.'IIMUD fDEf.XDG IESIUS
00'ftD ~C.lt(j aJtPMr Sl'l'E
... ....
~.
-.
Rf)1U)JN, Mmm
sl'A'l'US
-
1-
-
mat3r111 GIOJtDIA'1!:RS
..
,
Natural Attenuation
M'-t Preferred
..tural AtteNJ8tlon After SdJrce Removal
or Isolation
Preferred
bltlre PIUlle Withdrawal with Off-Site
Disposal
Dltlre Plume Withdrawal with O1-6ite
Treabnent and Discharge
tbt Preferred
RJt Preferred
Entire Plune Wlthdrawa1/Injection vith
Off-6ite Disposal .
R)t Preferred
Entire Pltllll! Withdrawal/lnjectJon vith
OI-Site '1'relibnent and Discharge
tbt Preferred
. .
Entire Plume Withdr8MI1 vith 0I-61te
'1'reatll81t and P.eJnjection
Not Preferred
- .
Highest. Contamination Plume Withdrawal
with Off-Site Disposal
Highest Cont8nlnation Plume Withdrawal
with OI-Site Treatment 8IId Discharqe
~
Not Preferred
Not Preferred
...---
I L
~_~"-'L-"L"
(DIem;
-oq
-....
--
-
-
Req'" res an eetbeted 400 ~am to achieve planning
objectives. No action alternative.
. Method achieves planning objectives, but rt!(JJirm IOn:J
period of inplementation.
Excessive costs du! to ISG-,ear bplenmtatJon period.
WltlxJraval network negatively 1npacts residential area.
Excessive costs due to ISG-,ear InplenmtatJon period.
tlitlxJrawal neblork negatively inpacts residential area.
Excessive costs due to 2G-,ear inplementation period.
tlitlxJrawal/Jnjfd:ion netwrk negatively inpects
residential area.
Excessive costa due to 2G-,ear iwplementatJon period.
WlthJrawal/inject:ion netwrk negatively inpact8 .
residential area.
Excessive costs due to 2G-,ear InplenentatJon period.
WJthdrawal/inj(!(:tion ~twrk negatively inpocts
residential area.
Excessive costs due to 4~ar inplenentatJon period.
tlithdrawal netwrk negatively inpact8 residential area.
ExceBBlve costs due to 4()..year inplementatJon perJ0(1.
tlithdraval network negatively inpact:s residential arf':t.
..
--~
---
----
..
-------
--.-'.. ...,.
TABLE 8 (cont.)
MJ1'!RtW1'IVB RDDIAL JIC1'I(M MErIIm IUAtLm ~tG JmI4'S
IIm'm ~.u~ OJI»Mr SITB
-
RfJB)IN, ht-;nuJ
.~-
-
-
_1
-
SHM3rJt1 GRCDDlATERS
Highest Cont_inatlon PltIne WlthJrawall
Injec.1:1on with off-eite disposal
Highest Cont8lnation PI.. WlthJrawal/
Injection with on-site treatMent
!Ihd d~8Charge
Highest Cont:8lnatlon PltMe WithJrawal
with on-elte treatment and reinjection
Contatr881t of Waste Pond PI-.e by
Bentonite Clay Slurry Wall
~inRmt of Highest Cont8dnation
nea plune by Bentonite Clay Slurry Wall
fn-elte treabnent by enhn:ec1 Biological
)!gradation
mRrICtAL All) ~ miLs
E:xaJvatlon with Off-Slte 'l'reabent: by,
- Incineration
- LBndfi11
.....
S'1WltJS
...:_L
Not Preferred
Not Preferred
Preferred
Preferred
Not Preferred
-
Not Preferl'ed
Not Preferred
Not Preferrec1
-
.... v"
aJ9ftIl'S
.... 'I .
~-
Excessive costs In C'OIIparJson to on-elte treatment
options. Negatl w inpact: to residential area during
5 yearn r8llediatlon.
.
Excessive costa In conpuJson to reinject wnethod. Nec)-
stlve Inpect to residential area during 5 years reme-
diation.
Removes SaN! cont-lnants flO8 site. ktlvattd carbon
absorption cost-effective treat:nent lllethod. Negathe
Inpact to residential area during 5 year r8lnlJaUon.
TeclwdcaUy eccept8ble and bplenentmle. khje~n
planning objectiveB. Negative long-term jllpBct to re-
sidential area because cont-mants remain on site.
Achieve sane d>jectjve as teste pard slurry MIll at
highest mst. Negative long-term inpact to residen-
Ual area because contanlnants rmain on site.
Not Inplenentable. Degree of treatment possible- not
defined. Potential for high msts due to recJ.lire-
nents for closely ~ injection neblork.
,
EJrcesslve coPts. Not Inplementable s1noe no OOIIplimt
facilities currently available.
Not ilplementable since no OOIIplalnt. facUlties cur-
~ently ftVailable.
-.....
~
-
-
-
v .. ~ ---.,.,
=-
-------
-.' ... .... -
-,-
TABT.F G (cont.)
AL'rERtM'IVE JafDIAL ~ON JeMD; IEI'A1UD fI:RfDI[fG RPJDIrS
UNl'JID ~dG aJ1PNN srm
~
"V .1-
-
-
.
RfJe)JN, m1m
&_---
-
--
-
..
.
EaeavRtlon with OI-stte Dillp0881 by:
- ReM ConpUant Landfnl
: I
Preferred
- Waste Enca(8Ilatlon
Not Preferred
.
Excavation with OI-Site Ifreel8ent- bya
- Jnclneration
Preferr~
- Biological Slurry
t10t Preferred
- LInJ Panning
IiJt Preferr~
- Cheldcal OXidation
tbt 'Preferred
~
-.-.... .......... l
. Includes on-slte reburial of treated vastes.
... ----
~L_-a.
S'l'A'lUS
aMEHI'S
----
------
.
Tecbdcally acceptable and Inplenentable on-slte
waste ftenaqenent s]ternative. Requires long terM
naintenance and IIOMtOl'ing. Alters appear8nCe of
neigltJOrrooo and use of lancJ.
Tectniat]Jyacceptable and bplenentabJe on-site
waste alternative. However, acconplishes sane
soil remediation 8S infiltration controls at
greater cost.
- TecbdcaUy ~8ble andlnplemenbble, cost
effective, destructive tecmology.
Tecb'lically unprcwen. Ray have excessi~ costs.
RecJlires large tract of Jand.
tong bplenentatlon perkx1 due to on-site land
availability. .
Excessive costs.
--
_L&L-----~&.L"
~--
III:.. L-
-------
.-.,~.. - ....-.---
TA8t.E 8 (cant.)
AL~~A. IBBHAL ICrIoft ~11a.Uj IEINtm fDEP.IfItG RISIUS
UNI'1m OcfaOtltG CDtPANY SITB
-.
L
I L&.- J
- .L.a.... L
. .'~....
Preferred
(2 C8psJ
Least mstly tectnology. Pequlns lorqtel1ft _intenance
and nonitorlng. PermnenUy alters neigtiJorlood and
use of land.
Preferred
.
Teclnlcallyacceptable anrJ iJplenen~le. 1\:npurarily
alters neJgttlOrhood. O1certainty of future avail-
ability of c:atpli8l1t landfll1.
Preferred
TecmicalJy acceplable ana Inpletlent!ble. ~porarf1y
alters neighborhood. flare mstly than landfill, but
facilities lOre likely to becofte available.
Inconsistent with planning mjecti\!M.
RJt Preferred
Preferred
GraUng, revegetation, ana fencing r~dro:l for
restoration. Monitoring and maintenance rt!(JJirec1 to
ensure effectiveness of clean-up.
tt»t awlicable to site cond!tions.
Dlffieu1t to bplement.
Not Preferred
Jbt Preferred
~~'V"
--.
-
-
-------
14
of the feasibility study.
involved:
The final evaluation of groundwater alternatives
1.
Recovery of the entire plume, treatment by granular activated
carbon. and reinjection of the treated water;
2.
Recovery of the pentachlorophenol plume, treatment by granular
activated carbon. and reinjection of the treated water; and
3.
Natural attenuation of the contaminants after source removal
or isolation.
Recover Entire Contaminant Plume
Recovery of the entire 43.000.000 gallon contaminant plume would require a
network of 97 recovery wells. The contaminated groundwater would be treated
by granular activated carbon units onsite. The treated groundwater would
be reinjected into the shallow zone via 41 reinjection wells. The large
number of wells is required because of the low yield of the shallow zone.
limiting the rate at which any single well can be operated. The cost of
this alternative is estimated to be $7.7 million and would take over 20
years to complete.
Recover Pentachlorophenol Plume
This alternative would provide for the recovery of the smaller plume
contaminated with pentachlorophenol. Approximately 7.000.000 gallons of
contaminated groundwater would be pumped and treated by carbon adsorption.
The treated water would then be reinjected into the shallow zone. The cost
of this alternative is estimated to be $2.7 mtllion. and would require five
years to camp1 ete. '
Natur'al Attenuatio" "
Attentuation involves three processes; dilution, adsorption. and possible
biodegradation. Upon the removal or isolation of the contaminated material
in the former pond area. one would expect that the concentration of of
contaminants in the groundwater would decrease over time. Some migration
of the plume (1/2-3/4 mile) would occur during the attenuation period of 400
years.
Natural attentuation is the selected alternative for the shallow groundwater
at United Creosoting. Removal or isolation of the soils in the former pond
area will be necessary. When the source control remedy is completed. the
contaminant loading to the groundwater will be eliminated. At this time.
dilution adsorption, and biodegradation will begin to-decrease the
-------
....
15
Both of the plume recovery alternatives were eliminated because of the lack
of potential of the shallow zone as a groundwater resource. Because there
are no identified current or potential receptors, the contaminants are not
considered to pose a threat to health or the environment.
The cost of the natural attenuation is estimated to be $120,000. The
capital cost is associated with plugging most of the existing monitoring
wells and restoring the well areas to pre-site investigation conditions.
A few wells would be left in place as part of the remedial post-closure
monitoring program.
Soils Alternatives
Alternative 1 - No Action
)
Section 300.68(f) of the National Contingency Plan specifies that the
"No Action" alternative be evaluated. The only activities associated with
the "No Action" alternative would be site restoration to pre-investigation
conditions and, future groundwater monitoring. The restoration inv01ves
plugging most of the monitoring wells and repairing any damage to yards
from well installation. Groundwater monitoring would be necessary to
ensure that the groundwater objective was met.
In the absence of remedial action, the long term stabilization of the site
cannot be assured. The primary threat to public health and the environment
remaining under the "No Action" alternative is the potential for direct
contact with contaminated subsurface soils. Site improvements involving
excavation in the former pond or tank storage areas could expose persons to
concentrations of contaminants that may represent a chronic health threat.
Because the "No Action" alternative would not effectively mitigate threats
to human health and the environment, it is eliminated.
Alternative 2 and 3 - Excavation and Onsite Disposal
Alternatives 2 and 3 involve the excavation of 84,000 cubic yards of 50;15
contaminated with greater than 100 ppm of polynuclear aromatic hydrocarbons.
These soils would be disposed of by either construction of an onsite landfill,
maintained in accordance with the performance standards in the Resource
Conservation and Recovery Act (RCRA). The net present worth of the onsite
landfill alternative is $12 million; for the onsite incinerator, $29 million.
Net present worth includes capital cost.and operation and maintenance (OIM)
costs. OIM costs are discounted at a rate of 10S for 30 years.
Alternative 4 - Permanent Cap and Slurry Wall
Alternative 4 involves the consolidation of all of the contaminated surface
soils in the former pond area. A multi-layered cap would be built over
both the pond area and the storage tank area. A slurry wall barrier would
be built around the former pond area to prevent outward migration of
-------
o ~
16
feet thick. average 35 feet deep, and tie into the aquitard beneath the
shallo\-I water bearing zone. The net present worth of this alternative is
estimated to be $3.9 million. O&M activities would involve long-term
inspection and cap repair, and groundwater monitoring to ensure the integrity
of the slurry wall.
Alternative 5 - Temporary Cap. Future Disposal
Alternative 5 is similar to Alternative 4 in that the contaminated surface
soils would be consolidated in the former pond area. However, -in this
alternative, a temporary. single layer cap would be placed over the
consolidated soils. No slurry wall would be constructed around the pond
area.
The EPA would periodically assess the availability of offsite disposal
facilities permitted to handle dioxin-contaminated wastes. New. emerging
technologies that may be applicable to the site would also be evaluated.
When an appropriate disposal method becomes available. the contaminated
soils~~-t~~p~nd and tank areas would be excavated and disposed. This
assessment period would continue for five years. If no facilities or
appropri ate technol ogi es are i dentifi ed, the permanent cap. and slurr-y wa 11
alternative (Alternative 4), or possibly the.,oQ,$ite incinerator alternative
(Alternative 3) would be implemented. .' .
t w '-J" '.
The cost"of A~ te;riaH~'e '5'~9~pen.d~"~Jp,o.'1 jFi'~" ~:1t:{ma,~e di s'~~~a l method :S1!:l.ected.
Costs using ~~~V~~:;6ri'a~J ~.t;~'P~~'~\!~,~.~~d.~,t'r..~11i~teP4~lo~:\:, ..~.~! '.f-~'~
.~ I. -.. 1 .: t- t' L :' \ .. ',.
(Disposar'ff~th"8d"'; - '.'/U-. . Cost (millions)
. .....'1 ':-A.)~ I.~.! . ..
."..~~~(a~\"~~/SlUrry Wall
Offsite Landfill
.,,-::Iff(:g ,PIE: .' 'l?' ',\
$4.5
....
.;t .. ~..; ~..-
. . ~:> :. ;.H:r~e", 0
. ~)1.....:\t,;\'" b~-~, 1, 'f:: ..' .,n,".
Onsite Incineration"': '; ~'nt: ~",i
. . - ....
, -.- . .
- ~ ~ - . '. .~ .;. r-' :,_1 ~: ~J . -
j . .
!(~ "
$31..0
$140.0
Offsite Inci~~~~tion ...
A comparison1()ftthe effectiveness, feasibility. implementability. and cost
of these alternatives is presented in Table 9.
Relocations
Permanent relocations
As noted previously, six houses were built directly above and adjacent to
the fonner waste ponds. As part of any remedial alternative, except IINo
Actionll, these houses will have to be demolished in order to address the
contaminated subsurface soils in the pond area. These relocations are
necessary to remove or isolate the contaminated 50i1 beneath the houses.
-------
TARLE 9
~ .. J..... ..... .,.. ...
..unr GOIOInYJt
..wID ~ CDftNr ...
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. .
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of vIU.'" ~er. to .,1ftIJ Ind"'8Uon of I_I" In p81ft1ng .,...
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to '.1-* In ....,...,.
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tt!dnolOlJlee. ..let" ebjfd.IW!8. IIbM not: I8dI"CIIIIIII ""Ur III
-"'1........ ......,..,. dl,,'" ''''''181 I- -, 401 J'!8r8. ......,1.-
tlon with 8011. 8ft'" ...,. of .lte. fUllelbl. ....,..... "~er
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fOf8ft ...... pn1I -.
-
.... 8IIt ""'1'" 81to -
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fut.. 18- eont.8rt vltIII
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- CIP - ~.-.nJI . .-- ...... aa..
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ar-:U,. ....,h..
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_lilt.... for 5 JNI8.
--
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..
-------
17
The following houses are affected by permanent relocations: 5, 6, and 7
Brewster Street and 5, 6, and 7 Columbia Street.
The homeowners and tenants residing in these houses will be provided with
penmanent relocation assistance through the Federal Emergency Management
Agency (FEMA) in accordance with the Uniform Relocation Assistance and Real
Property Acquisition Policy Act of 1970. It will be necessary for a
governmental unit to acquire property rights in the properties in order to
carry out the remedy.
Temporary relocations
Provisions have been made for the temporary relocation of residents in the
subdivision during the excavation of the soils in the former pond area.
The purpose of these relocations is to protect residents from possible
hazards from the generation of dust and volatile organics during excavation.
In the feasibility study, temporary relocations were estimated for a 6
month period for all households within 100 yards of the pond area. In
actuality, the period of relocation will be defined by the time required
for excavation. During the remedial design, a more definite radius of
relocation could be developed by modelling the migration of volatiles
released from the pond are~. Temporary relocation assistance will again
be prov;de~,through FEMA.
Community Relations
t..rl
'-; r .';'
Public interest in United Creosoting has been high, particularly" among the
homeowners in the residential area onsite. Several meetings were held with
the Tang1ewOQd East Homeowner's Associati.on during the cours'e of the RIfFS.
These meetings'wer'e"hefd.to keep the'peop1e most affett'ed by the site. . .
up-to-date on project activities. "Approx;-rilately'100 people attended these
meetings.
, -' . I
_. .
The public notice period began on August 8, 1986. The results of the
feasibility study and the proposed alternatives were presented to the
Tanglewood East Homeowners' Association on August 20, 1986. This was
followed by a three-week public comment period beginning on August 22 and
ending on September 12, 1986. A public meeting was held to present the
results of the feasibility study on Augut 28, 1986 in Conroe, Texas.
Approximately 125 people attended the meeting. Most of the comments received
at the meeting were from homeowners requesting a complete buy-out of the
residential area. Onsite incineration, in lieu of a total subdivision
buy-out, was received favorably by a few commentors at both the homeowners'
association meeting and the public meeting. Responses to the comments
received during the comment period are outlined in the "Community Relations
-------
~
18
Consistency with other Environmental laws
The Environmental Protection Agency's policy is to select a remedial action
that attains or exceeds applicable or relevant and appropriate Federal
environmental and public health requirements. Other Federal criteria and
advisories and State standards may be used, with adjustments for site-
specific circumstances. In the absence of the cleanup standards defined by
regulations or health advisories, a risk assessment may be used. This
assessment should derive the concentration of contaminants which would
represent a 10-6 cancer risk. ~
)
Standards have not been established for PAHs and PCP in soils. A health
based standard for 2,3,7,8 - tetradioxin (TCDD) of 1.0 ppb in residential
soils has been established by the Centers for Disease Control (CDC) in
Atlanta. Guidelines for other isomers of dioxin and for PAHs may be
developed by comparing the toxicity of 2,3,7,8 - TCDD to the toxicity of
these other contaminants found in the site soils. This method was developed
by the EPA Carcinogen Assessment Group in Washington, D.C.
Based on this method and a review of the data by CDC, the presence of
dioxins, dibenzofurans, and PCP, United Creosoting does not pose a health
threat. However, the PAHs found may present a chronic threat. Eliminating
the direct contact with these soils is consistent with the intent of
Superfund to meet applicable and/or relevant Federal regulations.
The Resource Conservation and Recovery Act (RCRA) and the Uniform Relocation
Act of 1970 also have an impact on the selected remedial action. RCRA
defines the performance standards to be met by methods used for the disposal
of hazardous wastes. Any offsite disposal facility used for the disposal
of the contaminated materials will have to be fully permitted under RCRA
(as opposed to having interim status) and certified for dioxin contaminated
wastes (Federal Register, Vol. 50, No.9, January 14,1985, pp. 1978-2006).
These facilities must also be in compliance with the Superfund Offsite
Disposal Policy (Federal Register, Vol. 50, No. 214, November 5, 1985, pp.
45933-45937).
As stated previously, all relocations and property aquisitions would be
done in accordance with the Uniform Relocation Act of 1970. This will
ensure that all residents affected will be treated equally, and that the
security and safety of the subdivision will be maintained.
Recommended Alternative
Section 300.68(i) of the NCP states that lithe appropriate extent of remedy
shall be determined by the lead agency's selection of a cost effective
remedial alternative that effectively mitigates and minimizes threats to
and provides adequate protection of public health and the environment." To
. this end, Alternative 5 in combination with natural attenuation of the
shallow groundwater plume is the recommended remedial action for the United
-------
.
19
Purchase and demolish six houses built directly above and adjacent to
the former pond area;
- Permanently relocate the families currently in those hcuses;
- Consolidate the contaminated surface soils onto the former pond areas;
- Construct a temporary cap over the pond area;
- Periodically assess the availabilty of offsite facilities permitted
for the disposal of dioxin-contaminated wastes and applicable emerging
innovative technologies.
- Excavate and dispose of the soils in the former pond area and soils
contaminated with greater than 100 ppm of PAHs in the former stoarage
tank area by the selected disposal method.
- Backfill and provide final cover in the pond and storage tank areas.
- Groundwater attenuation through natural processes of dilution and
adsorption.
The areas of soil contamination to be addressed by the recommended alternative
are illustrated in Figure 10. The rationale for the selection of Alternative
3 is outlined below.
The selected alternative (consolidation, temporary capping, and future
disposal) is currently the most acceptable alternative given the combination
of site conditions and contaminants at United Creosoting. Permanent onsite
remedies (alternatives 2 and 4) represent long-term storage of the waste
and is less acceptable environmentally. Perpetual maintenance of the
surface cover and groundwater monitoring wguld ~e req~ir~d in order to
ensure the i ntegri ty of the closure systein'.' .
Onsite incineration (Alternative 3) wouldf elimlnate tt1~ potential problems
discussed above by destroying the contaminants over a relatively short
period of time. However, concerns regarding the ti~]fness and safety
of this remedy were expressed during the comment period. :EPA believes that
a safe and environmentally sound incinerator can be designed, constructed,
and operated at this site. However, projected costs are somewhat higher
than the low range of the selected alternative. In addition, EPA would
prefer to have the consensus of the community and State and local government
before applying this technology in a residential setting.
Currently, dioxin-certified transportable units are not available. EPA
believes that the availability of these units will increase in the near
future and that these units can be designed, built, and operated without
adverse effects to public health or the environment. However, until enough
of a track record can be developed to prove this to the public, it may be
more prudent to operate these units in more rural areas.
Alternative 5 also offers interim protection until offsite disposal facilities
fulfill the administrative and ,technical requirements for the disposal of
dioxin contaminated wastes. The alternative may also offer protection
until an applicable and reliable innovative technology becomes available.
By removing the contaminated surface soils from the residential area
immediately, future impacts to the subdivision will be minimized. This
alternative also provides the opportunity to remove the waste from a densely
-------
...-. -
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~-
Figure 10
Contamination to be Addressl
During Remedial Action
UNIT[D ~A[OSOT"G FUSt'
STUDY
-------
~
20
At the end of the interim period, a second Record of Decision will be required
to document the selection of the permanent remedy.
Cost of Selected Alternative
The estimated capital cost of Alternative 5 ranges from $4.5 million for
future offsite land disposal to $140 million for offsite incineration.
Costs for emerging innovative technologies may be difficult to asses at
the present time. Factors such as site preparation, material and energy
requirements, and disposal requirements must be evaluated before a cost
estimate can be developed.
Operation and maintenance (O&M) costs are estimated to be $43,000 per year
during the interim closire period. O&M costs during the post-closure period
are estimated to be $6,000 for groundwater monitoring. The post-closure
cost will increase to $50,000 if no offsite facilities become available and
a permanent cap and slurry wall are built after the interim closure period.
)
Operation and Maintence
Operation and maintenance (O&M) activities required during the interim
closure period will include inspection and repair of the temporary cap and
landscaping in the cap area. O&M activities during the post-closure period
include routine groundwater monitoring to ensure that natural attenuation
is occurring after excavation of the waste. If a permanent cap and slurry
wall are installed at the end of the closure period, post-closure O&M
activities will also include periodic cap inspections, repair and landscaping.
The Trust Fund is available for O&M costs for a period of up to one year
after completion of construction of the remedy. The State of Texas will be
responsible for the inspections and monitoring for a period of at least 30
years after completion of the construction. If ,signif;,cant .increases in
contamination are detected during the post-closure period, additional
corrective measures will be evaluated.
Schedule
The schedule for the remedial design and construction of the selected remedy
for United Creosoting is currently dependent upon reauthorization of
Superfund. The remedial design will begin as soon as funding becomes
available, either through reauthorization or a continuing resolution. The
design phase will take an estimated 12 to 18 months to complete.
Consolidation of the surface soils and construction of the temporary cap
will begin as soon as possible after completion of the design. This phase
of construction is estimated to take 8 to 10 months to complete. The
excavation and offsite disposal phase is estimated to take 12 months to
complete. However, this estimate is dependent .upon the disposal method
-------
21
Coordination with the Federal Emergency Management Agency to conduct the
permanent relocation activities will begin in the Fall 1986. Contingency
monies have been made available to the Region to begin the relocation
activities. It is estimated that these activities will take at least one
year to complete.
. ",.1'.
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-
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DE'ARTMENT 0' HEALTH' HUMAN SERVICES
PYblic Htllth Service
Aglnl:V for Toxic Substanct.
and Oistllt 'h;iltrv
Memorandum
~..uaZ7 17. 1'86
~ t iq 1)1r.c ur
Offic. of '.a1th A.......at
lubf~ ..alth ~......atl Voie.d C~.o.ot. Itt.
Cnrol, !...
To
.~.' Cart a. lick..
tu~tic ..alth "vi.or
irA bal.n '1
plC'C'I'tV' IUMMm
!hi vnit" Crlo.otl 'lte contalD' ~e.i4ual ,otynucl.a~ I~omatlc hydro-
Clr)ODa ('AR'a) lod ,.nt.cblo~opheuol f~om tbl forelt wood-pre.ervlac
activit!.. on tb. .Ite. !bele relidue. It. pr~ltil1 .ub.urflc,. bOWIY.r.
ebut a~t 1'.otat.4 "tar .at." locatee! I.n .,adou'" rll148Dtial 711'4.. !b.
Invbonalntal '~ot.ctlon "IDCY (EtA)'. .'1 tOil '1. ~equ..tlc! an Icceptlble
ellanup levlt for th.., r..idue.. »U~1D& an Octob.~ 10, 198' conf.~.ac.
eaU. .it~ JIlloa 'I. a .,a1ue of Ib(rppli'lo~' tot.i~'AR!1\".urficial' I'ld.-
'Intla1 .011 .1' ,uli.~t.a a. . vatu. tbatCla uoltklly to'rliult in I
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Aftlr .....loa '1 1'..18.,.14 thl Jul, 31. 1985 lupll'fuII.d lapt.latltin Croup
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cal .concamll1acloD. they I'lqUI.te4 a..i.tlnci ill '8V,loplaa a ."1&0 .,alul
'01' thl ,18aald ollanup of cbe .ite.
BoemiDTS IIUIKIR
I'.' K_O~.D4u. fl'- DOD VUlt.... RA 1.811011 'I, ~tobl~ 10, I"'..
I. lI-ol'lndu. IrOil a.oral A. Joal., Iuperfuad IIIpt.llltatlOD C~CNp.
Ju1, 31. 1..5.
,. ATID& Uatced Cr.o.ot. .ite till.
eme'fJ.Mt1lAX~8 ~ ~AftVA'Y1
!bl 'l'lacl,ll oOlltamll1ant. 8t thia licI II'I ol'eo.otl 1114 ,llItach1oI'0-
,hlaol. fbl "PO'U~I p.thway. I~' 'iract CODCIct .ith OODtaminate4 101.11
aad CI'IO'Otl ~..14utl. au' tbe con.umption of contamioated ,rOU04Yltll'.
!hI blahl.t 1..11. or cr.o.ott coat.minltloa ~.,orte4 II'I loe8t" ill "tl~
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P..e 2 - ~. Cad a. 11ck-
of the '011. lacept for tbe few reportedl1 i.olated "tar .at.." tbe
,~ed08iuatt oout_lnatiou at the ,ite 1. .ub.urfac.~ Without .ub.tautlat
.ffort OD tbe ,art of the hum aD ,opulatlou. thl. ,ub.~rfact cDGtamluatlou
,r..eut. little opport~Dlt1 for cODtact. !ha toell arouu4vlttr 1. COD-
tam!uate4 witb botb peDtacbloropb.Dol aud cb. aorl .0lubl1 ,AI',; bow.var.
tbi. .atlr, ~.port.dlYi i. Dot c~r~eDtly beiDi u.ed for doa,'tlc .fVrpo...i
BUCtJIIIOW
I
ID a ,ubll.hed artle~e . the CeDter. for ~l.ea.e Control CCDC) 4eri~..
an action IIV.1 at wbicb to timit buaan 8ZpOlure for 2.3i'.8-tetracbloro-
4tbe.lo-p-41ozin (2.'.',8.-tCD») cODtamiDated re.ldeatial '011. !hi.
..rlved .alue .al 'a.,. u,oq ..t~apollttoDI from aD1aal toalclty ..perl-
.'Dtl (iD.Clu4iq carclaoleDicit1 ad r.proc!uctl.~. effecu) to ,olltble
bvaln blalch .ff.ct!,in order to ..tisate a r.a,oDable level of rilt for
2.'.7)8-!CDD. A 10 ..ee'l lifetime rilt wa. uled tu the 4~tlo"8Dt
of cbi. !CDD .011 1...1.
!be IDvlrODmeDtll 'rotectloD AaeDcJ~' Carcl.oa8u AalelW8eDt2Cro~p ba.
derl~e4 . retative poteacy in.~ for aor. tha~ 50 cb-=lcall. !be ord.r
of ....1t~4. ,ote.cy i.4. fo% ,2.,,7,8-~D it .laht,; .b,l1, that for
',D&o(a)pyreae it oDly three', ft~.. 2,3,.,7.8-'fC1)J)h cOD.14,r,d co b. five
order. of .alnlt~de 80re ~ot.nt al I CITC1Doa.n tbaD 'euEoCa)"reae.
Vllae o~ly tbi. ord,r of 8A&Ditud8 difference in ,ot'DC1 )ltWI'~ tbl two
cb8mlcal. ID' the CDC-4erived re.ld'Dti.t .011 actlOD 1..,1. .1.,. 100.000
ppb of bID80(')PYlln....,uha1ut co-I, ,ppb of Z.'.,1.8-!Cm) 1D '011.
"
ID chi .04,1 .1" co'4.rlv. the 2.'.7,8.TCD,t .011 .alu.. tbe 1..uaptloD
cOKlr.lq t1l. Douat of .0U iqe.t84 bat 'leD .hCND to be bLab. ' A
~8Clltt uDpubli1hld lC1&d, b7 CDC b" .bOVD t1l, 880uut of .0U iq..ttd )7
childr'D of t1l1 .oU-Iatiq ..e ~aDl" from 0.1 to 1 I~- '11: 48)' (I.
11lder p.r.oclt .000uDlcIClon). Tbu., cb. 804e1 ..tialt. for 8011 1111'-
~lon 4urlua the p.rlod of .iaimum hJa18ne i. 8Kce..1ve b7 It lealt aD
order of ...aitu"i 11acl chI och.1' .011 iDl..~ioD ~It'. i. the .04el 8r.
al.o 'Itimat... tb,r. i. a lood likelihood tbat tbw,r 8r. 11'0 iD .rror.
,o..lbI7 'y 801'1 thaD 8D or',r of .IIDlt,,4.. !b"I, the aodel .er, lik,ly
over'lt~lt'l the totll l1flt~e .011 iDle.tioa 8Kpo.ure b, at l'l.t ODe
order of ...alt,,'"
%a additioa. cb, 80'11 cODtala. a faccol' to accouDt for tb. 'Dyiro~'Dtll
.earl.ltloD of tbe Ipeeirte ch..leal. lb. factor for 2",7.8-!CD~ I..waed
a 12"'lr bllf-l1t, lD '011. Whl1, tb, DU.'I'O'" r£B'. ha.. I 1'118' of
'Ilf-life .a1ue. ift .urflc, loll. wbicb will '...epladlat ",OD the Ip8Oi-
fie .0U IDd cl1matoloalcat coocUtlonl lDCouat.~e., eveD tbe ..1au.
half-l1f, for tbe 80.t '..radatloD-ralitt.nt compoua4 i. la.. thaD tha
.al~1 1..iaDld for 2,'.7,8-TCDb iu tha .od81~ IvID .it1l . Ita ,Iar half-
llf., I perlonl 11f't18, ..po.ur. .ould be lub.taDtiatl, redue,d .h.D
c08,ar,' to that l.t1mate' with tbl 10Dler half-l1fl u... LD the tCDD rl.k
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r8&' , - IIr. Clrl I. liek..
!bu" OOD.id.riaa OAt, tb... two a~.a. for .~ificatioA' to thl _oil
..po.ura 804,1 u.,4 co 4..,10p cb, 2,S.7.8.-TCnn rl.k ...e....nt, itO.R
~. 'een that . ~e.idu. of 100 ppm of rAB'. in loll 1. Rot lik.l, to
,r"eDt I '1I"1110."t bva.n 1a,.lth b...r4.
. IR ad4itlon, "b,n oODd4ulQ& thl '!aDitloa"ce of CODt_iRadon at tbe
.ite, tba fact. that al1 .AB'. I~e Reitber carciDo,'Dlc Ror (for tbo..
.U.pICtlct CarC1DOaeIU) ., potlnt a. b,uo(a'P1r.nt ..t bt . part of the
...lu.tiOUt ~ a fir.t .ppraxlaaclon of I .ice, it ." bl .1114 to a..
the total r£l cODceAtratlon to 'ee.rmine an ..t~ate of the _!anlflclnc,
of the contamination. loweY.r. .h.n 4.t.ralAIAi cl.aDup actLoD, th, u.e
of l.omer. aDc! compouDd., .blcb ar. t~1y 'l&a~40u., .ould be .o.e .ppro-
priate .bln that iDfo~tiOR.t. ..alllbil.
!bl applleatioD of thl .o4e1 to Obtain tbe 100 ,pm cllanup CODcIDtratiOD
ha. al.u..e! that e11 PA!', are a. poteDt a. beD&o(a)pyreDe. Iln.r.tl,
COD.idered to be the 80.t poteDt carcinOCID of ,hI ,AI'.. !bi. i_, 10
flct. Bot viii.. " cbo.. 'jI C08pOUDd. which Ir. conlider.d to ,. IUlPec-
ted or probabla clrciDoaeA', comprl.. 1... tbaD b,lf of the &ot,1 'AI
cODc.ntr'tlo~ at aAY .ite. !A addicioD. .aDY of tb..e compouDdl 4"1IDa-
ted al .u.,eetf4 or prObable carciDoaaD'. art 8uch 1... pot.nt thau
blD80Ca)pyrIDe .
Tbe IDvlro..ent.1 Protection Ac.De7 ~8C'Dtl, ~e1.a.ed I ~raft Wealtb
j4vl.o~i'l for pentachloropb'Dol ID driDkiaa .ater,' !he life-cia.
.atue tor adult. in ,'I. 40cuaeDt il 1050 aa/l. fbil y.lul il lu\.can-
tlal17 are.tlT t'an tbe 21 aa/l 4i.cu..e~ for u.e lD IValuati.. tb.
l..oun4".ter cODtaieaclon at thb .Itl. la..' U'OD tbb ... naluation
for p.At.cblorophenol tD 4rlDktD& .ater. the DI.4 for aDd eat.~t of
l~oaR4"ater r8Dovation fo~ thi. Ittl I~oul' 'I rlCoD.i4.re4.
ue~KJi]).i~Jmrl
'01YDuc1,.r Aroaatlc IJd~ocarboD (PAl',) oODCIDt~atloA' in ~1.ld'Atlal
loll 1... thaD 100 ,pm .houl4 pr"lnt no .1lnifleaDt leute o~ ch~oDle
'.a1th thr.at co bu.aa ~'alcb tbrouab aD, Dor.aal routl of ..,olurl.
!be ..Id fo~ 1.4 atlDt of Irouu"atlr ~8Doyation Ihou14 ,. r8COD.I.e~8d
...ee! UpOD thl receDt DA W.a1th £dvbol'7 for pelAtacblo~o,hnol.
W. '0'1 th1. iDfo~t!OD i. v_eful to 1OU. ~. .
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1. Kt.broulb, I.'., 'alk, I., .elhr, ,,' and rril', G., -ilalch
Iapl1cation. of 2,'.7,8-cltrachlorodlblnlodioxlD (TCD~) ContamiDation
of ae.ldIDCi.l '011,- 3, tox. . ~vir. ..a1th, 14 .'-'3, 1'84. ~
. 2.
itA, -B..tch '11.,lm.DC 'ocument for Iplchloroh1drlD, Final ..port,-
IPA-600/1-8'-032r, Pt. 7-62, 1'84.
S, wlY.luatioD of tbe earciDOlenlc 111k of Cb8mical. to IU88D.. .
'olfDucl.ar Aromatic Compound., 'art I, Cbemioal. lDviroaa.Dtal aDd
laparimentat 'ata." tlA~ ~po,r.~h.. .olume '2. tnt.rDatLonal "aDCY
for ".Iarch on Cancer. tIAC. Lyon. rraDcI, 1'83.
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irA. Office of Drlnkiaa Water. Crit.ria aDd .taDdard. Dlvl.ioD. ~raft
..altb jd.l,orr. '.pta8bar 1'85.
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UNITED STATES
ENVIRONMENTAL PROTECTION
REGION VI
1201 ELM STREET
DALLAS. TEXAS 75270
AGENCY
United Creosoting
Conroe, Texas
Responsiveness Summary
This Community Relations Responsiveness Summary is divided into the following
sections:
Section 1.
remedial action.
Overview.
This section discusses EPAls alternatives for
)
Section II. Background of Community Involvement and Concerns. This
section provides a brief history of community interest and concerns raised
during remedial planning activities at the United Creosoting site.
Section III. Summary of Comments Received durin~ the Public Comment
Period. Comments are categorized by topics and EPA s responses are
provided.
I.
OVERVIEW
At the time of the public comment period, EPA announced several possible
alternatives for corrective action at the United Creosoting site:
No Action - No action would be taken to reduce the potential site hazards.
The groundwater would be monitored to track the movement of the pentachloro-
phenol (PCP) plume. This action would cost an estimated $120,000.
Excavation and Onsite Landfill - More than 84,000 cubic yards of comtami-
nated soil would be excavated and placed in an above-ground landfill
constructed on the site. The landfill would meet all State and EPA require-
ments. This alternative would prevent direct contact with the highly
contaminated soils and remove the source of the groundwater contamination.
This action would take approximately one year to implement and cost an
estimated $12 million.
Onsite Incineration - The contaminated soil described above would be
excavated and destroyed by an incinerator constructed on the southern end
of the site. This incinerator would be dismantled and removed from the site
after all of the contaminated wastes from the United Creosoting site have
been destroyed. This action would take 2-3 years to' complete and would
cost an estimated $29 million.
Ca~ and Slurry Wall - All of the contaminated surface soils would be
conso11dated into the former pond area. A slurry wall (or underground
barrier) would be constructed around the former pond and storage tank areas.
This area would then be covered with a multilayer cap. This alternative
prevents direct contact with the highly contaminated soils and isolates the
source of the groundwater contamination. Approximately one year is required
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Temporary Cap and Future Removal - A temporary cap would be constructed
over the tormer pond and storage tank areas and a fence would be built
around the capped area. The temporary cap would prevent direct contact with
the highly contaminated soils and reduce the potential for further groundwater
contamination. Currently, no facilities are permitted to incinerate or land-
fill wastes containing cholorinated dioxins; therefore, EPA would periodically
assess the availability of offsite incineration capacity or offsite landfill
capacity.
If no offsite facility becomes available within five years, EPA would
construct a slurry wall and replace the temporary cap with a permanent cap.
Estimated costs.for the permanent cap alternative are $4.5 million; offsite
incineration, $140 million; and offsite landfill, $26 million.
Recovery of the PCP Plume - Seven million gallons of contaminated ground-
water would be pumped to the surface and treated by carbon adsorption and
reinjected into the aquifer. This action would take an estimated five years
and $2.7 mi 11 ion to canpl ete.
Based upon the results of the Remedial Investigation and the analyses
performed in the Feasibility Study, EPA proposed the temporary cap and future
removal as the corrective action for this site. This alternative as well as
all other alternatives for source control involve permanent and/or temporary
relocation of businesses and affected residents. Natural attenuation was
proposed for the shallow groundwater.
L
~.
Judging from the comments received during the public comment period, the
residents want a total buyout and relocation of all of the residents in the
subdivision. As a second choice, the residents expressed a desire that EPA
destroy or remove the contamination quickly and give the neighborhood a
"clean bill of health".
II. BACKGROUND ON COMMUNITY INVOLVEMENT
During the 1940's, when United Creosoting began operation, the site was
relatively isolated from any significant population concentrations or urban
development. By the time operations ceased in 1972, some development had
occurred in the general area. The property remained essentially dormant
unti 1 redevelopnent of the area began in 1977.
Residential property owners were basically unaware of the previous land
usage and the potential hazards until the site was added to the National
Priorities List in September 1983. An initial property owners' meeting was
held on September 6, 1983, to discuss the Superfund program and current site
c'Onditl9ns..~- ~:vasCm~jori~y of those fn attendanc.e demonstrated a very high
, eV'ef "'of-"t$it.n"f- : .:.s,,» .'-""' .~" "';-~ ...~- - .., - - - '. . --.
..:~~~ '::;'.:~L/~'-~~~< .., -:-;:,~ ~ ' ":. - ~ .- - - -- ',c.
. Another ~t1ng"w.a,s held on. December-8, 1~~3, -to expl ain the immediate
resp.onse action plann'ed for the site. This action included capping a highly
contaminated area and constructing drainage structures to improve drainage
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In February 1984, representatives from the Centers for Disease Control
in Atlanta, the Montgomery County Health Department, and the Texas Depart-
ment of Health met with the area residents to discuss the health oriented
questions. Most of the concern centered around the long-term effects of
continuous exposure to PCP.
The results of the remedial investigation were mailed to the area
repositories and presented to area residents at a meeting in January 1986.
The major concerns were health effects and the economic stability of the
neighborhood.
III. SUMMARY OF PUBLIC COMMENT
The press release announcing the public comment period and public meeting
was issued on August 14, 1986. The comment period began on August 22 and
ended on September 12, 1986. A meeting was held with the area residents on
August 20 to explain the results of the remedial investigation and to outline
the alternatives presented in the Feasibility Study. Seventy-four persons
registered at this meeting and 17 made oral statements or asked questions.
The public meeting was held August 28, 1986, in the Travis Junior High School
auditorium in Conroe, Texas. Seventy-eight people registered at the meeting
and 21 made oral statements or asked questions. Written comments or ques-
tions were received from an additional seven citizens during the public
comment period. A petition signed by 78 homeowners was submitted to EPA
requesting that their homes be purchased and the families relocated.
During the public comment period, there were comments/questions regarding
the following:
Comment 11:
Why is a cleanup necessary if no health threat is posed at the
site?
Response:
Since EPA cannot be assured that the contamination will remain
buried, remedial action is necessary to mitigate the future
threats which may be posed by future excavation in the pond
area.
Comment 12:
Has EPA considered the impact on the deeper aquifers in
recommending natural attenuation for the shallow water
bearing zone?
Yes. EPA believes that the clay layer separating the 25-foot
sand and the 85-foot water bearing zone is an adequate barrier
to vertical migration of the contaminants from the site and that
the lower zones will not be impacted from the site.
Response:
Comment '3:
Wouldn't it be easier to clean up the site without the houses
in the way?
Response:
In the former pond area, yes. This is why the six houses over
the pond area must be demolished. The surface soils addressed
as part of the remedial action, are found in open areas. No
demolition of any structure ;s necessary for access to these
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Comment 14:
Response:
Comment 15:
Response:
Comment: 16:
)
Response: :
Comment 17:
Response:
Convnent 18:
Response:
Comment 19:
Response:
Comment 110:
Response:
Comment Ill:
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Wouldn't it be cheaper to simply cover the contaminated area?
Yes. This alternative was presented as the "cap and slurry
wa 11" a 1 ternat ive . Wh i 1 e th is a 1 ternat he is cheaper than others
considered, it would require perpetual operation and maintenance
to ensure that the contamination remains in place.
Wouldn't it be more cost-effective to buyout the entire
subdivision? .
No. The cost of buying all of the homes would have to be
added to the cost of the selected remedy. EPA could not buy
the houses and then not implement a remedy to address the
contaminated soils at the site.
Are realtors and financial institutions liable for damages
by handling the properties in the Tanglewood East Subdivision.
No.
Will excavation have any impacts on air quality?
The emission of volatile compounds is likely during excavation.
However, provisions to ensure that the air pollutants aren't a
problem will be developed during the design of the remedy.
Possible methods to minimize emissions include temporary
covers over the work area, sprays to keep particulates down, and
controlling the rate of excavation. Continuous air monitoring
will allow EPA to adjust to changing air quality condition
during excavation.
Does EPA ever get involved in recovering losses or joining
in lawsuits with homeowners?
EPA does file lawsuits against responsible parties for the
costs incurred from the Trust Fund. EPA does not join in
lawsuits where the recovery of Fund monies is not involved.
From which houses were vacuum cleaner samples taken?
During the 1983 response action, samples were taken from #5
and 16 Brewster, 16 and 17 Columbia, and 110 Darnell. These
homes were selected because they would have been most affe,ted
by the open area of the former pond. .
Are creosote compounds in the water supply of the subdivision?
No. The subdivision uses the city water supply, which has not
been impacted by United Creosoting.
If EPA files a lawsuit for cost recovery, will EPA get paid
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Response:
Comment 112:
Response:
Comment 113:
Response:
Comment #14:
Response:
Comment 115:
Response:
Comment 116:
Response:
Coinment #17:
Response:
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5
Payment or satisfaction of a judgment depends upon: 1) when
the judgment is obtained and 2) when enforcement of the judgment
occurs. Individual lawsuits will vary in length. The EPA has
not filed any lawsuits against responsible parties at this
time. .
One commentor offerred to buy all of the houses if given
the remedial action contract. He would then clean up the site
with biodegradation.
EPA is prohibited by the Federal procurement regulations from
entering into such an agreement without competitively bidding
the project. EPA also does not believe that the acquisition
of all of the houses is necessary for protection of public
health and the environment. Therefore, purchasing the houses
would not be funded.
Do the residents in the subdivision have a say in what
alternative is chosen?
Yes. All comments received from the public are reviewed.
evaluated, and taken into consideration prior to the selection
of a remedy.
Why are there no facilities that will accept dioxins?
No facilities have yet obtained the necessary permits to handle
dioxin contaminated material. Because of the toxicity of one
isomer of dioxin, 2,3,7,8, - tetradioxin (a compound found
at United Creosoting) special precautions were required by law
for the handling of all dioxins. Commercial facilities have
not yet modified their operations to be compliant with the new
procedures.
If an incinerator were brought onsite, what impact would
the emissions have on air quality?
None that would have an adverse effect on public health or the
environment. The operation of the incinerator would have to
conform with the performance standards in the Resource Conservation
and Recovery Act for dioxin certified incinerators as well as state
and federal clean air laws. These standards were developed to
protect public health and the environment.
Is temporary relocation voluntary?
Yes, it is voluntary.
Several people commented that creosote odors are evident
near the site in the morning.
This may be true, but it is unlikely that the odors are being
generated from United Creosoting. Routine air monitoring done
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Response: This may be true, but it is unlikely that the odors are being
generated from United Creosoting. Routine air monitoring done during the
remedial investigation did not show any air quality problems from the site.
It may be possible that the odors are being generated by another wood
preserving plant currently operating in Conroe.
Comment: *18: What risks would people in close proximity to an onsite
incinerator be exposed to?
Response: Operation of an incinerator should not pose a risk to anyone
living or working near the site. However, EPA recognizes the current site
uses and would include additional safety precautions in the incinerator
design.
Comment *19: Who at EPA will select the remedy for United Creosoting?
Response: The Regional Administrator, in consultation with the Assistant
Administrator, Office of Solid Waste and Emergency Response in Washington,
will select the reme~.
Comment #20: Why weren't the potential problems at this site publicized
back in 1980 when it was discovered, or require that
further land sales be deferred?
Response: Neither EPA nor the Texas Department of Water Resources (TDWR)
had the authority to stop the developers from conducting business. A full
assessment of potential hazards was not available at the time TDWR warned
owners not to develop.
Comment *21: How long will it take to get started on the work on this site?
Response: As soon as Superfund is reauthorized, the design of the remedy
can begin. This should take 12 to 18 months. Construction of the remedy
should begin 6 to 9 months after the completion of the design. The time
required to complete the onsite incineration alternative is estimated to be
24 to 36 months.
Comment *22:
If a commercial facility does not become available, will
EPA review the problem for the public?
Response: Yes. In the event that the temporary cap may become a permanent
cap, EPA would hold a meeting to discuss this alternative.
Comment *23:
How accurate is the estimate of the location of the former
pond area? .
Response: EPA believes that it is very accurate based on the results of
the ground penetrating radar, soil borings, and the historical aerial
photographs.
Comment *24:
Is it safe to plant gardens in the subdivision and eat the
vegetables from these gardens?
Response: The Centers for. Disease .Controlhas .indicated to EPA that
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The uptake of creosote and pentachlorophenol in plants is minimal.
no adverse exposure to these compounds should occur.
Therefore,
COlll11ent *25:
Is there a risk for people digging their yards?
Response: Shallow digging (1 to 2 feet) a~where in the subdivision will
not pose a risk. Deeper (5 to 6 feet deep) excavations over most of the
subdivison would not pose a risk. Deep excavation in the former pond area
may expose soils which could represent a long-term health risk.
COlll11ent *26:
How many caps and slurry walls have failed over time?
Response: EPA does not have a specific number.
Comment *27: Will the subdivision ever get a clean "bill of health"?
)
Response: After review of the Remedial Investigation report, the Centers
for Disease Control has concluded that there is no current or long-term
health risk to residents with. no contact to buried contaminants. The clean
up approach selected for buried contaminants will remove the risk for
contact with buried materials. The procedure for removing the site from
the National Priorities List will document that any long-term health threat
has been mitigated.
COlllllent *28: WH1...r~stric.tions on buHding swinnning pools be placed on
homes in the subdivision?
'!'41 .'::.} l~1t' 'j...W',.::\'"1l4':
Response: No. Excava'Ubrrs HI' C'areas away from the former pond area will
not. present a.n .innnedi ate or long-term threat. Upon compl eti on of the
remedy, excavation anywhere in the subdivision will be safe.
Conment *29:" ;t~~«t~;~:;m:~t'of"s i te securtty will' be provi ded duri ng the
- temporary relocations?
, ",..."
Response: The' specific type of site security needed will be developed
during the re~dial_design by the Federal Emergency Management Agency.
Comment *30: Who were the developers of the Tanglewood East Subdivision?
Response: The developer of record is a company named Charles-Thomas, Inc.
Conrnent *31:
Have the ponds moved since the plant began operating?
Response: No. Based on the historical aerial photographs and the ground-
penetrating radar survey performed during the remedial . investigation, the
pond areas have not moved. Migration of pond material has occurred via the
shallow groundwater, but the ponds will not migrate:
COlll11ent #32: Where were the soils taken that were removed from the site
in July 1986?
Response: These soils, generated during the remedial investigation, were
taken to a hazardous waste landfill in Carlyss, Louisiana. These wastes
were non-dioxin contaminated materials. Approximately 50 drums of dioxin
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Comment *33:
If a slurry wall was installed around the entire subdivision,
would EPA be justified in buying-out all of the homes?
Response: No. None of the remedial alternatives for the groundwater would
require permanent relocations. .
Comment *34:
If dioxins are scattered throughout the neighborhood, why
isn't the entire subdivision addressed as part of the remedy?
Response: The concentrations of dioxins found in soil samples taken from
the residential subdivision were not high enough to pose a long-term health
threat. Therefore, the dioxins in the residential soils are not addressed
as part of the reme~.
Comment *35: Why won't EPA buy all of the houses in the Tanglewood East
Subdivision as part of the remedy?
Response: According to the National Contingency Plan (40 CFR 300.70e),
permanent relocations may be provided where it is determined that human
health is in danger. The purchase of all of the houses in the subdivision
is not necessary for the protection of public health and the environment.
Based on the resolution of the remedial investigation/feasibility study,
purchase of only six houses in the former pond area is necessary for imple-
mentation of the selected remedy. The remaining properties in the subdiv-
ision are not subject to short or long-term health risk.
Comment *36: Why wasn't biodegradation proposed as a remedial alternative?
Response: Biodegradation as a remedial technology was eliminated because
of site-specific considerations. Questions regarding the effects of soi1
type, the effects of chlorinated dioxin, and types of emissions generated
during biotreatment are very site-specific. In an effort to answer these
questions, biotreatment is being studied in the Superfund Innovative
Technologies Evaluation program. Because of the presence of dioxins at
the site, certification for the disposal of dioxin-contaminated materials
may be required.
Bioreactors were eliminated primarily due to engineering considerations.
Clay soils would be very difficult to handle in the mixing basin and to
de-water upon completion of the treatment. Clays may also pose a problem
by inhibiting biodegradation via adsorption. Well dispensed clays would
provide a tremendous surface area for adsorption of the contaminants.
These contaminants may not be available to the microbes for degradation.
Two other technical issues were considered in screening out biodegradation.
First, research from laboratory scale studies suggests that the presence of
chlorinated dioxins may inhibit biodegradation, extending the time required
to complete the remedy. Second, significant questions concerning the types
and quantities of emissions from both landfarm and bioreactors have not
been answered. Those emissions are particularly significant considering
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Comment *37:
Several commentors were concerned that their homeowner's
insurance policies would be cancelled during the temporary
relocation period.
Response: A homeowner's insurance policy would only be subject to can-
cellation during tenporary relocation if the home were deened "vacant"
that is, if substantially all of the furnishings were removed. If a
homeowner simply removes those personnel items necessary to relocate
temporarily, the home would be considered "unoccupied" and the insurance
policy would renain
in effect.
Comment #38:
If additional homeowner's insurance is required during the
tenporary relocation period, who pays for this?
Response: It is the homeowner's responsibility to pay for any additional
insurance coverage.
Comment #39:
Is the homeowner's right to sue responsible parties for
economic damages overidden by EPA?
Response: No. The homeowners can file suit against the responsibile
parties in an effort to recover damages which they have standing to
assert.
Comment #40:
What will prevent EPA from implementing the interim remedy
and walking away from the site?
Response: The Record of Decision, signed by the Regional Administrator,
commits EPA to complete the selected remedy. Secondly, EPA is committed
to adequately protect public health and the environment from long term
risks. The interim cap will not provide this type of protection.
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Attachment A
Community Relations Activities
Community relations activities conducted at the United Creosoting site to
date include the following:
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o An initial meeting was held by the Texas Department of Water Resources I Hazardo
(now the TWC) for the property owners and residents of the Tangl ewood . Informat
East Subdivisi on on September 6, 1983. US EPA r.
Phlladel,
o Similar meetings to explain the immediate response action were held
December 8, 1983, and February 28, 1984.
o The Community Relations Plan was finalized in May 1984 establishing
information repositories at the Conroe City Hall, Montgomery County
Library, University of Houston library, Rice University Foundren library,
and the Houston - Galveston Area Council offices.
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o The Texas Water CQTImission held a meeting on January 27, 1986, in Conroe
to provide area residents the results of the remedial investigation.
o The Remedial Investigation report was made available to area reposi-
tor;es on March 11, 1986. '
o On August 13, 1986, EPA and TWC representative met individually with the
residents and property own~rs most inrnedhtely impacted by the proposed
remedy.
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o The Feasibil ity Sf Jy was released for publ ic review and comment on
August 14~ 1986.
o EPA, TWC, coe, a~- Federal Emergency Management Agency representatives
held' a meetfng with -the area property 'owners 'and residents on August 20,
1986, at the St. Marks Lutheran Church in Conroe. '74 people attended.
o EPA representatives met with six area residents on August 26 1n Conroe
to discuss the aspects of incineration.
o EPA held a public meeting at Travis Junior High School in Conroe to
describe the RIfFS reports and to respond to citizens' questions.
78 people registered at the public meeting on August 28, 1986.
o The public comment period closed September 12, 1986.
o The transcripts of the August 20 and 28 meetings were sent to the area
repositories on September 19, 1986.
o This Responsiveness Summary was provided to all speakers at the public
meetings on August 20 and 28 and to all citizens who commented during
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