United States
Environmental Protection
Agency
Office of .
Emergency and
Remedial Response
EPA/ROD,R06-84:002
September 1984
Superfund
Record of Decision:
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TECHNICAL REPORT DATA
(Please read InStructions on the revene before completing)
1. REPORT NO. 12. 3, RECIPIENT'S ACCESSION NO.
EPA/ROD/R06-84/002
.. TITLE AND SUBTITLE 5. REPORT DATE
SUPERFUND RECORD OF DECISION: 09/25/84
Highlands Acid pit Site, TX 6, PERFORMING ORGANIZATION CODE
7. AUTHORISI 8. PERFORMING ORGANIZATION REPORT NO.
9. 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
401 M Street, S.W. 14. SPONSORING AGENCY CODE
Washington, D.C. 20460
800/00
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The Highlands Acid pit site is located 16 miles east of Houston on a 6 acre
peninsula. The site is bordered on the west and south by the San Jacinto River,
on the 'north by a wooded area, and on the east by a sand pit. The site lies within
the lO-year flood plain and has subsided 2.4 feet since 1964. An unknown quantity
of industrial waste sludge was disposed of at the site in the 1950's. The sludge
is believed to be spent sulfuric acid wastes from a refinery process. Waste materials
at the site exhibit low pH and elevated concentrations of organics ~nd heavy metals.
Extensive excavation with off-site disposal was selected as the cost-effective
remed~al action for this site. The selected remedy includes: excavating wastes to
the ground water level (approximate depth of 8-feet), off-site disposal to a RCRA
facility, backfilling the excavated area, constructing a temporary site perimeter
fence and performing ground water monitoring and site maintenance for 30-years.
Alternate Concentration Limits (ACLs) will be developed for this site. The capital
cost for the selected alternative is estimated at $2,407,000 with annual monitoring
and maintenance costs at $14,000.
Key Words: Environmental Impacts, Flood Plain, No Action Alternative,
Subsidence, Contaminated Soil, Lined Landfill Cell(s), Off-Site
Disposal, ACL, Groundwater Contamination, Ground Water Monitoring
17. KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS b.IDENTIFIERS/OPEN ENDED TERMS C, COSATI Field/Group
a.
Record of Decision
Highlands Acid Pit, TX
Contaminated media: gw, soil, sludge, I
leachate
Key Contaminants: sulfuric acid, industria
sludges, VOCs, metals, refinery wastes
1B. DISTRIBUTION STATEMENT 19. SECURITY CLASS (Tllis Report) 21. NO. OF PAGES
None 56
20. SECURITY CLASS (Tllis page) 22. PRICE
Nnnp
. 0
EPA Form 2220-1 (R... .-77)
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INSTRUCTIONS
1.
REPORT NUMBER
Insert Ihe [PA report number as it appears on the cover of Ihe publil:ation.
LEAVE BLANK
2.
3.
RECIPIENTS ACCESSION NUMBER
Reserved for use by ea~h report recipient.
4.
TITLE AND SUBTITLE
Title should indicate dearly and brieOy the subjel:tl:overa~e uf Ih~' report, and ~, disl'l;ly~'d pfOmi1wnlly. S... 'uhlitk. if \I,~',I, 111 ,malkr
type or otherwise subordinate it to main title. When a reporl is prepared in mor,' than 011\' vulum~', r"""illlh~' prim,lfY titk, a,ld vulal11\'
number and include subtitle for the specific title.
5.
REPORT DATE
Each report shall carry I dale indicating It least month and year, Indil:ate Ih~' hilsis UII whkh il \\as .....1~~'I~'d (/'.1!" JaIl' oli5.\11C', clDlc' ol
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PERFORMING ORGANIZATION CODE
Leave blank,
8.
7.
AUTHORCSI
Give name(s) in ~'()nventional order (10/111 R, Doc, 1. Rolxn Doc'. C'tc.). Lisr aUlhor's affilialloll if il difkrs frum Ih~' p~'rfurl1linj: ,"~ani-
ution.
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Insert if performing organization wishes to assign this number.
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PERFORMING ORGANIZATION NAME AND ADDRESS
Give name, street, city, state, and ZIP code, lisl no more than two levels of iln orj:ilni/,illiollill hireardl~',
10. PROGRAM ELEMENT NUMBER
Use the program element number under which the report was prepared. Subordll1atc numbl:r' m.I)' b~ il1d.I\kd m 1',1["lIlh,'"".
11. CONTRACT/GRANT NUMBER
Insert contract or grant number under which report was prepared,
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Include ZIP code,
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Indicate interim final, etr_. and if applicable, dates covered.
14. SPONSORING AG~NCY CODE
Ins~rt appropriate code.
15. SUPPLEMENTARY NOTES
Enter information not included elsewhere but useful, such as:
To be published in, Supersedes, Supplements, etc,
18. ABSTRACT
Include a brief (200 words or less) factual summary of the most sil!tnifkanr IIIformalion ,'ontain~'d III III,' "'I'mt. II ,"" ,,'purl '"lIlalll' a
significant bibliography or literature survey. mention ir h~re,
Prepared in cuoperatiun wllh. I r."'Slilllllll "', I'r~''''lIll',1 ,11"\111"'1"'1\,' uf,
17, KEY WORDS AND DOCUMENT ANAL YSIS
(a) DESCRIPTORS - Select from the Thesaurus of Engineerir.~ and Sl'iel1l1fi,' Terms Ihe proper ilulhurll~'d (,'rill' thai Idel1l1l)1 Ih~' miljor
concept of the research and are sufficiently specific and preci~e to bc u~~d as ind\::\. entries for calaloj.!IIIj.!.
(b) IDENTIFIERS AND OPEN.ENDED TERMS - Use idenlifiers for project nam,s, code names, eljulpmcnl dC\l~nators, ~'h:, U'II: III'ell'
ended terms written in descriplor form for those subjects for which "0 descriptor c>.iSls,
(c) COSA TI HELD GROUP. Field and group assignments olre to be taken from the 1965 ('051\ 11 Suhjn" ('ilI"j.!Clry Us!. Sinc,' Ihe ma-
jority of documents are multidisciplinary in nature, the Primary Field/Group assignmenU,) will be sp.:d.i,' di'\'Iplin~', all'a III' hurniln
endeavor, or type of physical object. The application(s) will be cross-rcfcrcRl.:cd with 'e,'undary I I\'Id/( ;roup as\'j!IIII1,'nls Ihal \\'11111111.."
the primary posllng' s).
18. DISTRIBUTION STATEMENT
Denote releasabilit)' to the public or limitalion for reasons other than security for example "H.elcil'l' (;1111111""'1." ('II" illIY iI';lil;"IIIiI~' III
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Insert the price set by the Nalional rechnicallnformation Scrvke or the Governmenll'rtnling Office, if knuwn.
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ROD ISSQES ABSTRACT
Site:
Highlands Acid pit, Texas
Region:
VI
AA, OSWER
Briefing Date:
June 6, 1984
SITE DESCRIPTION
The Highlands Acid Pit site is located 16 miles east of Houston on
a 6 acre peninsula. The site is bordered on the west and south by the
San Jacinto River, on the north by a wooded area, and on the east by a
sand pit. The site lies within the 10-year flood plain and has sub-
sided 2.4 feet since 1964. An unknown quantity of industrial waste
sludge was disposed of at the site in the 1950's. The sludge is
believed to be spent sulfuric acid wastes from a refinery process.
Waste materials at the site exhibit low pH and elevated concentrations
of organics and heavy metals.
SELECTED ALTERNATIVE
Extensive excavation with off-site disposal was selected as the
cost-effective remedial action for this site. The selected remedy
includes: excavating wastes to the ground water level (approximate
depth of 8-feet), off-site disposal to a RCRA facility, backfilling the
excavated area, constructing a temporary site perimeter fence and per-
forming ground water monitoring and site maintenance for 30-years.
Alternate Concentration Limits (ACLs) will be developed ior this site.
The capital cost for the selected alternative is estimated at
$2,407,000 with annual monitoring and maintenance costs at $14,100.
ISSUES AND RESOLUTIONS
KEY WORDS
1.
The no action alternative was eliminated
from consideration because of the threat
of pUblic exposure by direct contact, the
potential impacts on aquatic life, the
unstable nature of the site as a result
of subsidence and the site's location
in the 10-year flood plain.
Environmental
Impacts
Flood Plain
No Action
Alternative
Subsidence
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Highlands Acid Pit, Texas
June 6, 1984
Continued
ISSUES AND RESOLUTIONS
2.
At the time the ROD was signed, the Region
was to compare costs associated with dis-
posal of excavated waste materials in
lined and unlined cells. This informa-
tion was used to assess the final
disposal option.
3.
No remedial action was proposed for the
ground water at this time; data from the
ground water monitoring program will be
evaluated to determine if any future
remedial measures are necessary to protect
the environment and public health consistent
with RCRA 264 requirements. Alternate
Concentration Limits will be determined for
the site.
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KEY WORDS
Contaminated Soil
Lined Landfill
Cell(s)
Off-Site Disposal
Alternate Concen-
tration Limit
(ACL)
Ground Water
Contamination
Ground Water
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RECORD OF DECISIOO
REMEDIAL ALTERNATIVE SELECl'IOO
site:
Highlaros Acid pit Site, located south of the western end of
Clear Lake Road in Highlands, Texas.
Documents Reviewed
I have reviewed the followi~ dOClDtents describi~ the analysis
of cost-effectiveness of rertedial alternatives for the Highlands
Acid pit site:
- Highlaros Acid pit site Investigation, Espey, Huston &
Associates, Inc., and Roy F. ~ston, Inc., Dacember 1983.
- Highlaros Acid pit Site Remedial Action Feasibility Study,
Espey, Huston & Associates, Inc., and ROY F. ~ston, Inc.,
Deceut>er 1983.
- staff s\..ItI'IBries and recamendations.
- Transcripts fram the public meeting
Description of Selected ~y
- Excavate the waste material (depth of excavation approxi-
mately eight feet).
- Tra~port the waste material to a permitted Class 1
disposal facility.
- Backfill the excavated area with clean fill. '!he till will
include six inches of tq:>soil that will be seeded, mulched,
and fertilized.
- Construct a temporary site perimeter fence with warni~ signs.
- Install a groondwater m:>nitoring system.
- FerfODn groundwater I1Onitori~ and site maintenance for a
30 year period.
~larations
Consistent with the canprehe~ive Enviromental Response, Carpen-
sation, and Liability Act of 1980 (CERCIA), and the National
Conti~ncy plan, I have detecnined that extensive excavation
wi th off-site disposal for the Highlands Acid pit site is a
cost-effective remedy aoo provides adequate protection of public
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2
'lhe State of 'Iexas has been consulted and agrees with the approved renedy.
In addition, the action will require future cperation aoo naintenance
activities to ensure the continued effectiveness of the renedy. 'lhese
activities will be considered part of the approved action aoo eligible
for Trust F'\JOO nonies for a period of 1 year.
I have also deteDnined that the action being taken is appropriate when
balanced against the availability of Trost F'\JOO nonies for use at other
sites. In addition, the off-site transport aOO secure disposition is
nore ccst effective than other renedial action, and is necessary to
protect PUblic health, welfare and the envirorment.
I also will evaluate whether groundwater corrective neasures are needed
to protect the envirorment aOO public health. In the interim, I an
approving a groundwater nonitoring program.
~'V-~~
lee M. Thanas
Assistant Adndnistrator
Office of Solid waste and Emergency Response
~ 25 RiA
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SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
HIGHLANDS ACID PIT
Highlands, Texas
January 1984
Site Location and Description
The Highlands Acid Pit site is located in Harris County, Texas, 16
miles east of Houston, Texas. The location map of the Highlands Acid
Pits is shown on Figure 1. The site is located south of the western
end of Clear Lake Road, off Crosby Lynchburg Road in Highlands, Texas.
The site is immediately bordered on the west and south by the San
Jacinto River, on the north by a wooded area, and on the east by a sand
pit. The vicinity map of the Highlands Acid Pit is shown on Figures 2
and 3. The site is located on a 6 acre peninsula within the 10-year
floodplain, and has subsided 2.4 feet since 1964.
Site History
During the early 1950's, the site owner allowed an unknown quantity
of industrial waste sludge, to be disposed of at the site. The indus-
trial waste sludge, is believed to be spent sulfuric acid sludge from
a refinery process. The sludge may have been transported to the site
by barge. The wastes were then placed in an excavated sand pit or pits
located at the site. During the disposal operation, the sludge was
reportedly covered with sand. However, some areas of the sand pit were
uncovered by a sand miner approximately 10 years later. No generators
~r transporters of the waste sludge have been positively identified.
The site was flooded in 1961 by Hurricane Carla, at which time a fish-
kill was reported in Clear Lake adjacent to the site.
In May 1978, a telephone complaint was received by the Texas Department
of Water Resources (TDWR) concerning the site in Highlands (known locally
as the Acid Pit). The site was inspected by the complainant and a TDWR
representative. During September of 1978, waste sludge, sediment,
and stormwater samples were collected at the site. The stormwater
samples and leachate from the waste sludge samples were found to have a
low pH, low concentrations of heavy metals, and high chemical OxYgen
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......
-
-
-
-
-
-
-
--
~
i'
',THIN
@
(
'~
FIGUR
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,", i''1 'I,~.~I: "~'rrl,;::~; ,,:..:.
3 :l:".''''
t~ L.
. 8 . . .
j ~-
~
",. '""
J '
........
--
~~
~~.
/'
S8n Jacinto River ~
- .
.=.-:, =-,;:=--=
, -=--=-/
----------. ~
--- /'
-
()
\-
~~ .
o
Scale in Feet
1.000
2.000
@
FIGURE
Vicinity Map 01 Highlands Acid
2 - " G-i2\1
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GRENNEL
Cl-EAR
. .
Oil
OJ
. ,
, ,
. .r-, .~
INUNDATED AREA "' I' J (
(WASTE DISPOSAL ,SUSPECTED) ~ J}.
.Jf1. \ t /1:,0
~~ ~
VEGE TA TED
WASTE AREA
SOUTHEAST BARE AREJ
(AREA OF SECONDARY
WASTE OCCURENCE)
SOU THE ASr POND (INL ET)
a ESPEY. HUSTON 8 ASSOCIATES ,IN
n E/WJ,NCC",_. ENYllfOIIMIENTAL CONSVLTAIIIT'
SLOUGH
.\ \ \
.", ~.""
. ~
LAKE
FIQu" 3
SITE VICINITY MAP
. ,.
. ...
.1. .
."""OIIlM.n *c.u
o 100 '[~t
~-r"---'-'--'-'
r . JOO'
MAP SOURCE: ADAM!
,AL SURVEY. INC. 1982 PHOTO
-. ,/
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During June of 1981, six soil borings were conducted at the site and
three of the soil borings were completed as monitoring wells. In
October of 1981, groundwater samples were collected. Heavy metals
and volatile organics were detected at concentrations in the parts per
billion (ppb) range in these samples.
In August 1982, the application for a Cooperative Agreement for remedial
fnvestigation and feasibility studies (RIfFS) at the Highlands Acid Pit
sfte was filed. The Cooperative Agreement for $402,864 between EPA and
the State of Texas was awarded on September 30, 1982. In February
1983, Espey, Huston and Associates of Austin, Texas and Roy F. Weston
of Houston, Texas were selected to conduct the RIfFS. The site work
for the investigation was completed in July of 1983. The Feasibility
Study was started in July 1983 and completed in December of 1983. The
major findings of the Investigation and Feasibility Reports are discussed
f n the secti on ti tl ed "Current Si te Status. II
Current Site Status
The Highlands Acid Pit remedial investigation was a multi-disciplined
approach consisting of site surveying, air monitoring, soil boring and
monitoring well installation, test pit excavation, soil and groundwater
sampling, geophysical surveys, water level data collection, surface
water/sediment/benthos sampling, and land use and vegetation surveys.
The following is a summary of the results of the investigation.
The site is surrounded by surface water bodies associated with the river
system, Grennel Slough on the west, Clear Lake on the south, ponds in the
southeast and sand pits to the northeast. Therefore, the site is essenti-
a1,ly a peninsula extending into the San Jacinto River system. The total
area of the peninsula is about 6.0 acres. The hydrographic system is very
dynamic and is often subject to extreme water level fluctuations. Primary
hydrological controls on the site are Lake Houston, Galveston Bay via the
Houston Ship Channel, and hydrometeorological events within the local water-
shed. Lake Houston impounds the San Jacinto and is the primary controlling
factor on the flow in the river. The effects of the Houston Ship Channel
on the site are tidal oscillations and long term rise and fall of water
levels. The highest surface water level measured in the field investi-
gation was 3.5 feet mean sea level (MSL) in the Clear Lake (i.e., San
Jacinto River). The tide range observed was on the order of 1.3 to 2.0
feet. Ground elevations on the site range from 5 to 9 MSL. Therefore,
the higher ground elevations are on the order of 5.5 feet above the
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The site is flood-prone given the low relief between the site and the
river. Data from the Harris County Flood Control District indicate the
following approximate flood elevations at the site area:
Recurrence Period
Years
Water Surface Elevation
Feet (MSL)
9.6
14.4
16.9
22.1
10
50
100
500
Therefore, less than the 10-year flood will inundate the site, exposing
the waste material to erosion. This elevation only considers the
hydrology of the San Jacinto River drainage system, therefore, hurricane
surges add an additional flooding potential to the site.
The Highlands Acid Pit site is located on the banks of the San Jacinto
River and is geologically situated within recent meanderbelt alluvial
sediments (upper sand). This alluvial material ranges in thickness
from 18.5 feet to 26.0 feet with an average thickness of 22.5 feet.
The recent alluvium unconformably overlies the Beaumont Clay, and the
sharp contact between the two formations is evident. This clay deposit
is approximately 30 feet thick arcoss the entire site area. Samples of
the upper 1 to 6 feet of the cl~ were typically stiff, very slightly
silty. Below this clay interval lies a 23 foot to 26 foot thick sand
interval (middle sand). Below this sand interval another clay deposit
was encountered with a thickness of approximately 25 feet. Underlying
this cl~ interval a sand deposit (lower sand) was encountered with an
average thickness of 16 feet.
All of the groundwater for the region is furnished by two aquifers, the
Chi cot and the Evangeline. Both of these aquifers underlie the site.
The Chicot Aquifer is made up of the four Pleistocene age formations
and the overlying recent material. Therefore, at the site, the Chicot
extends from the ground surface to a depth of about 700 feet. The
Evangeline Aquifer is below the Chicot.
A water well inventory in the vicinity of the Highlands Acid Pit was
conducted. Within a slightly over a one-mile radius of the site, 11
(possibly 12) water wells were identified. Table 1 is a compilation of
these wells plus pertinent completion data and Figure 4 indicates the
general locations. All water wells were completed in the Chicot Aquifer.
Groundwater is not obtained from alluvial deposits in the site area and
vicinity. Well depths in the Chi cot are generally greater than 200
feet. However, one well was completed from 74 feet to 84 feet below
ground surface. Existing groundwater wells in the Chicot are not being
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TA8U 1
WATEn WILL IHV£..TORY ANIJ WI':I.I. COMPI.£110N DATA
W.I.., All II.."" D..pl"
A Tnwn 0.1. O",Ih C..I... C..I... 8,...lnl 01 I,"'" hel... 0.1"..1 M..I""" Uee 01
No. Ow...., Ih Iller Com,. 01 Well DI.. n"plh Unit Sur lart, (J.lum M...t.r~m,.,,1 101 url W.I.., n........
6S-16-4Ul J. Mcn-.... J. W. lun. ".. UI J lU Chlenl JO 11 s..,I9" Hnne "- In"... "081 Ul 1o UII.
1 U. W..II....I,..,...I.
65-16-405 W. 8. Willi... Low" W.I.., Well. "61 411 . 401 Ch8eo' J6 110 AUI 1961 So"', a D SeNe. "10... 4n'l 1o no
111 411
65- 16-406 Con," I!,."I A.I. Pump. Well .... '" . lU Chlc"1 " I" Ma. 1'J61 So.h,1 0 Ie,... 'ro.. n I In 1I6
Ie",'ell '" 1116
65-16..501 II..... Co. 'WO lAy.... Tee.. Co. ..., 481 161 415 Ch'enl ]I T,E . Ie..... 'ro.. 41' In 411.
Nn. I W..II I . 411 o."lnal ""plh ... 5'11.
W..1t ."......," I.. I""J.
n..powl"" ,I..'" UI liP'" In I''''. .......
65-16-'0) lIa..1a Co. 'WO "',..e T"... Co. ..., 416 II 411 Chtrn' J9 "6.1 Ma, 1961 T,E P C..I... .1011.. "n... 411 1o 416.
No. I W"lIl 6 416
6S-16-505 M...1a ('.0. WO . m M..M..I..'..'" "to 606 . to) Chlenl J9 .0 Apt 1940 """" "- '1 .. 0' .cre.... "10"'.'" In 511'.
"0, I 1'0..."..., 1 n......I". ,1..1.. or 'IOn Ipm .lIh
6 606 " " "'.."..-n I.. 1940, "..II
........,..".
, 6S-16-S!: J. M. c...fI,," M.,.I" Gllbe,I "11 .. I It {:hlcol JO J... 1911 C..ln".lnll"d fro... 14-84.
. 65-16-'" II. W. '.on II. T. Ch.p..... 1911 '" I U, ChIco I IS' AUI I'Jn D C..ln" .1011,,01 fro... US-US'
, 65-16-5N J. M. Su........ MIII.rd ~....... .,,, Joo t 190 Chl..ol 110 s..,I91S Sub, I! 0 C..I... .1..11"" ".... zerO-JOO.
111 JOO
. 65-16-5N C.,III...11 .........'. W.le, Well "" 114 t U. Chlcnl IS' Ju11918 Soh 0 IJupllc.I I! w,,11 .1 Ihl. Inc .11.....
III U4
0 65-16-5r C_u..... W.ler Shopp. W.le, W..II 1911 J41 6 U6 {:hlr.ot " Apt 1911 P C..I... .1011,," I...... 111-Jn.
Ceo.p. 4 )41
65-16-SW Well ,loll"''' hat .... ".t.....
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I. J
i: .,/
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Continuous water level data was collected during the site investigation.
This data indicates that a hydraulic connection exists between the
upper alluvial sand and the San Jacinto River. This was evidenced by
the close correlation of fluctuations of ground and surface water. The
average permeability of the upper sand is 5.08 feet per day, or 1.8 x
10-3 em/second. This permeability is typical of fine sand and is
sufficient to allow active interchange between the upper sand and the
surface water bodies.
Groundwater, in the upper sand, flows radially from the site and
discharges to Grennel Slough, Clear Lake, and the adjacent sand pits
(See Figures 5 and 6). Approximately 45~ of the groundwater leaving the
site discharges into the sandpits. The remaining 55~ discharges to
Clear Lake and Grennel Slough with the majority flowing toward Clear Lake.
The groundwater velocities and discharges into San Jacinto River (Grennel
Slough), Clear Lake, and the sand pits are summarized in the following
table.
TABLE 2
Discharge
(cu.ft/day) Velocity (ft/yr)
San Jacinto River 19.0 14.8
Clear Lake 20.9 8.2
Sand Pits 32.8 14.1
The distances from the waste areas to the surface water bodies are
about 20 feet to San Jacinto River, 100 feet to Clear Lake, and 50 feet
to the sand pits. Using these distances with the groundwater velocities
for each respective direction of flow, the travel times for groundwater
from the edge of the waste area to the surface water bodies are 1.4 years
to San Jacinto River, 12.2 years to Clear Lake, and 3.5 years to the sand
pits. Therefore, sufficient time has elapsed for waste material in the
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Subsidence is a factor affecting the site. Due to extensive ground-
water withdrawals in the Houston area. approximately 2.4 feet of subsi-
dence has occurred in the area since 1964. However. subsidence has been
ocurring in the region since the early part of the 1900's. Since 1976.
the Harris-Galveston Coastal Subsidence District has been successful in
curtailing pumpage in the area and has managed to reduce potential subsi-
dence rates to virtually zero. If groundwater demand increases in the
future. approximately 3 to 4 feet of additional subsidence is estimated
by the year 2000. Several investigators postulated that faulting in
the area has been aggravated by subsidence. During the field investi-
gation no direct evidence of faulting was discovered at the site location.
Figures 7 and 8 are aerial photographs of the site vicinity for 1955 and
1982 indicating the location of the waste area and the impact of subsidence.
Surface water runoff at the site conforms to the site togpography. The
site is composed of three drainage basins which drain to Grennel Slough.
Clear Lake. and the sandpits. Calculated runoff for the vegetated area
of the site to Grennel Slough is 34.5' of the total precipitation. or
approximately 16.3 inches per year. Surface runoff in the bare
area is approximately 50' of the total precipitation or 26.6 inches
per year. An estimated 15.7 tons of sediment per year are eroded from
the bare portion of the waste area by this runoff. Runoff from the
bare waste area on the site flows southeastward through a drainage
course and collects in a swamp in close proximity to the north shore of
Clear Lake. Soil and sediment samples collected in this area and immedi-
ately south in Clear Lake indicate the presence of slight contamination
both in the swamp and the northern fringes of Clear Lake.
To evaluate the nature and distribution of waste at the site. soil and
core samples. groundwater samples. surface water samples. sediment and
benthos samples were collected for evaluation and laboratory analyses.
It appears that the waste disposal pits were relatively shallow and.
based upon the results of the field investigation and interviews were
less than 10 feet in depth. The waste materials at the site are
characterized by a low pH. and elevated levels of total organic carbon.
sulfate heavy metals and organics consisting of benzene. toluene.
xYlene. and phenols. The wastes above the water table include the
original waste materials. runoff waste. and highly contaminated black
sand. This area covers about 1.45 acres. To calculate the volume in
this area, the depth to the groundwater table was taken to be an average
of 8 feet. The volume contained in the 1.45 acres is approximately
19,000 cubic yards (yd3) with an estimated weight of 25,000 tons.
Within the shallow alluvial sand (upper sand) there are about 77.428 yd3
which includes the 19,OOOyd3 of original waste and dissolved geologic
materials encompassing about 2.51 acres. The geological materials bordering
this discolored zone are also contaminated, as evidenced by sol1 water.
chemistry. This peripheral zone plus the 2.51 acre area contained about
-------
..
15
The groundwater in the upper sand at the site is contaminated and
is discharging into the Grennel Slough, Clear Lake, and the sandpits.
However, given the dynamics of the surface water system, the presence
of the waste constituents in the surface water system were not detected
above what was determined to be background. The only exception to the
above is the sandpits northeast of the site, where elevated concentra-
tions of sulfate and total dissolved solids may be due to discharge of
contaminated groundwater. These elevated readings may also be caused
by surface runoff. However, hazardous constituents were not detected
in the sandpits.
The major contaminants present in the soil/waste and the groundwater at
Highlands Acid Pit are summarized in Table 3. Each contaminant is
presented with the range of concentrations, as well as an average
concentration, found during site investigative work. An estimated
weight of each soil/waste contaminants is also presented.
TABLE 3
SUMMARY OF SELECTED SITE CONTAMINANTS
Contam;nant Groundwater son /Waste
Range* Average* Range** Average** 10ns***
Lead <0.01 - 0.82 0.19 <0.5 - 185 49.2 1.2
Manganese 0.015 - 39.4 14.5 0.5 - 112 15.7 0.4
Chromi urn 0.005 - 0.772 0.354 0.5 - 1.2 0.7 0.02
Berylli urn 6 - 24 11.0 0.3
Benzene 1 - 80.6 29.3 <2.5 - 822 454 11
Toluene 0.005 - 0.202 0.048 <2.5 - 21.2 13.5 0.3
Xylene 33.5 - 417 216 23.6 0.6
* Uni ts - mg/l
** Units - mg/kg
*** Based on estimated 25,000 tons of contami nated soil/waste (19,000 yd3.
-------
16
Groundwater elevations in the shallow alluvial sand range from +1.64 feet
MSL to +2.25 feet MSL. The groundwater elevation in the middle sand was
determined in one well and found to be -1.53 feet MSL. Groundwater elevations
in the lower sand range from -57.02 feet MSL. to -64-25 feet MSL. Therefore,
groundwater level elevations decrease with increasing well depth, and there
is a vertical gradient creating a potential for vertical flow from the
upper alluvial sand to the lower sand intervals. However, the low permeability
of the intervening clays between the sand units, the lack of evidence of
faulting at the site, and groundwater quality in the deeper sands suggest
that the deeper sands have not been impacted by waste materials.
Two areas of secondary waste deposition were investigated as part of
this study. These are the inundated area in Grennel Slough west of the
site, and the southeast bare area. No significant amounts of waste
were found in the inundated area. However, the results of the
investigation indicate that the inundated area may have been an area of
secondary or minor waste deposition. Waste materials are present in
the southeast bare area as a result of runoff and erosion from the
Clear Lake. The data indicate that waste materials are discharging
into Clear Lake immediately south of the southeast bare area.
The results of benthos sampling and evaluation indicate no measureable
impact to these organisms. This is probably due to the strong dynamics
of the San Jacinto River system which dilutes ground and surface water
as well as sediment runoff from the site.
One major impact associated with the site is exposure of the waste to
the hydrologic system. The upper groundwater at the site is contaminated
to a degree that the water is unfit for any practical use, and is
discharging to highly utilized surface water (i.e. the sand pits and
Sap Jacinto River system). However, no measureable impact was found to
date. Floods are easibly capable of inudating the site and washing the
waste materials directly into the San Jacinto River system. Continued
subsidence could permit the water table ,to rise into the waste materials,
increasing the discharge of contaminants to the shallow groundwater and
adjoining surface water bodies. The potential exists for approximately
14 tons of additional contaminants to reach the hydroligic system, with
the possibility for significant adverse impacts on aquatic life due to
-------
17
.'
A second major inpact of the site is hlli\an contact with the waste. '!he
San Jacinto River canplex is an active area of recreational activity.
'!he sand pits ~jacent to the site are used for swimming by the local
residents, as evidenced by a rope swing on the western shore of the
sand pits which is ~jacent to the waste disposal area. Fishing from
the banks of Clear Lake is also apparent due to the presence of fishing
equipnent (lines, lures, etc.). '!his is consistent with the known
facts that the San Jacinto River is an area of intensive sport and
ocmnercial fishing and recreation.
'!be following types of aquatic species are known to be present near the
Highlands Acid Pit:
- Mullet
- Crabs
- Killy Fish
- Catfish
- Grennel
- Bass
- Shrimp
- Silverside
- Perch
- Sh~
- Brean
'!he aquatic biota in the river system represent the J10st likely receptor
of off-site contaminant migration. A large fishkill reportedly occurred
in Clear Lake when the site was flooded as a result of Hurricane Carla.
'!he fishkill may have been the result of contaminants released from the
Highlands Acid Pits during the flooding. Due to the very dynamic hydrologic
environment at the site pollutant transport Jrodeling could not be done in a
cost effective manner.
Several threatened or endangered species are known or suspected to
occur in Harris County, 'texas. Endangered species inclooe the American
alligator, 9::>uston to~, brown pelican, southern bald eagle, peregrine
falcon, At twater' s prairie chicken, least fern, red-cockaded \IOOdpecker,
and the paXllefish. '!hreatened species that occur in the comty inclooe
the southeastern bat, reddish egret, white-tailed hawk, white-faced
ibis, swallOlrl-tailed kite, osprey, wood stork, 'texas horned lizard, the
lDUisiana milk snake, and the Rio (kande frog. Based on habitat
preference, several of these species may occasionally have direct
contact with the Highlands Acid pit site, however, no specific information
is available.
Vegetation analyses at the site indicate reduced growth of species on
the site. '!his situation may result in contaminants being passed
t~h the food chain to higher organisns. Wlile no specific analyses
were performed to assess the degree to which this passage occurs, it is
possible that the contaninants could reach hmlanS. Mechanisns inclooe
hunting of browsing animals, and waste materials being blown onto any
nearby vegetable crops. Sane of the contaninants at the site are
acutely toxic, while others are known or suspected carcinogens, III1tagens,
teratogens. '!berefore, a potential threat exists to hl.lllaJ\ health through
inhalation, ingestion, and absorption of containmants. FOtential hl:lMn
health risks of specific contaninants are discussed in Appendix A of
the Feasibility StOO}'. '!he Hazard Ranking System (HRS) determined
that the greatest potential hazard to the local p:>pulation is oons\mIPtion
of fish which bioaccumulate toxics. '!he HRS estimates that the equivalent
-------
18
Enforcement
011y one potentially responsible party, the landowner, has been identified.
Attenpts to identify the generator(s) of the waste have been unsuccessful.
'!he identified party is on social security and does not have the financial
assets to pay for the cleanup of the site. ~ rea:mnend that the FUnd be
used for the cleanup of this site.
Alternatives Evaluation
'!he remedial action objectives for Highlands Acid Pit developed in the
Feasibility Study have been slightly JOOdified to IOOre clearly ~ress
the nature of c:xmtanination at this site. '!he objectives are as follows:
. Control off-site migration of wastes by surface and
slbsurface pathways to mitigate future environmental
inpacts on surface waters and groundwatersi
. Minimize potential for hllTlan contact with waste materials.
'!he selected objectives are based upon (1) maintainiB3 existing contact
recreation, non-contact recreation, and fish and wildlife propagation
uses of the nearby surface waters, (2) maintaining present use of l0\0i/E!r
aquifer as a water supply and (3) prOlJiding a soil and air quality on-
site conpatib1e with existing recreational and developed land uses in
the area.
Deve10pnent of specific criteria or standards to measure how the
objectives are achieved, is difficult for Highlands Acid Pit, since the
main concern is to protect the environment and PUb1 ic health fran
potential risk to future exposure to wastes. Since the surrounding
surface waters have not been impacted to date, it is EPA' s opinion if
the surrounding surface waters are required to achieve specific EPA
water quality criteria (w;JC) based on surface water uses, all objectives
should be met. Relevant WJC are shown on Table 4 along with average
contaninant concentrations in the groundwater and soil/waste. Due to
the carcinogenicity of several waste contaminants and/or high concentra-
tions of specific contaninants, the potential for exceeding woe exists
if a:XIitional soil/waste contaminants are permitted to leach into the
shallow groundwater or by direct migration of wastes into the surrounding
-------
19
TABLE 4..
WASTE COOCEm'RATIOOS AND SPECIFIC WJC
CDntaninant Average Concentration WJC (ng/l)
Groundwater ~ Soil/Waste (ng/kg)
lead 0.19 49.2 0.1701
Chrani \JI\ 0.354 0.7 0.0211
Berylli\Jl\ 11.0 0.0001172/0.134
Benzene 29.3 454 0.0402/5.34
Manganese 3 14.5 15.7
xylene3 216 23.6
1. Aquatic life, freshwater acute.
2. HlItIan health, carcinogenicity at 10-6 risk level, via aquatic organisms,
only.
3. N:> established WJC, however, high concentrations are of concern.
4.
Lowest species mean acute toxicity, freshwater.
'!he Feasibility Stlrly developed several remedial action methods to achieve
the above objectives. '!be applicable remedial action methods that were
screened are shown in Table 5. In addition to the methods outlined in
Table 5, the no-action alternative was also considered but was eliminated
based on its inadequacy for meeting response objectives to mitigate the
site specific problems and the fact that pathways exist for significant
-------
20
eh
ESPEY, HUSTON & ASSOCIATES, INC.
TABLE 5
POTENTIAL REMEDIAL ACTION METHODS
4
1. Site Mmaaement
,.;
0 Waste .tabilization
.t Grading
o
o SuZ'face water diversion
. 0 Revegetation
M' 0 Monitoring and maintenance
j - z. Infiltration Controls (Cap aystems)
o Syuthetic membrane
o Clay
o Soil admiztures
o Site management (.ee 1 above)
3. Waste Fization
o In situ
o Removal/fix/replace
-. 0 Site management (see 1 above)
4. Ezcavation with Off-Site Disposal
.'If
0 Disposal as hazardous waste
o Fiz ad dispo.e as aolid waste
.... 5. Waste Encapaulation
::: Cap ayatem. (aee Z above)
.- 0
-'
0 Liner system.
~
- compacted clays
- 8JDthetic membranes
- asphaltic linen
..,; - concrete mixtures
- IOU admixtures
-------
6.
7.
.
~ 8.
...~
.6 9.
~
, -
~
~
r-
...
11
.i
~
..
21
eh
ESPEY. HUSTON & ASSOCIATES, INC.
TABLE 5 (Concluded)
mcmeration
Land Treatment of Waste
Treatment and Utilization for Energy Recovery
-------
22
'!he renedial action methods were screen~ using the following criteria:
.
Technical Feasiblity
Environmental Effectiveness
.
.
Inplementability (Time Frame)
.
Cost-effectiveness
'!be technical feasibility was COI1'prised of implementability, operability,
and reliability.
.
'1b be implementable, a technology must be able to be succes-
fully applied or accanplished.
'1b be operable, it must be practical and feasible.
.
.
'1b be reliable, it must be dependable and proven.
'1b assure the above conditions were met, only proven technologies (as
opposed to stat~f-the art) were considered.
'!be enviromnental effects of a remedial action strategy are an especially
important evaluation criterion. Operations that created additional
adverse impact or significant risk of impact were avoided. 'lberefore,
applicable technologies were evaluated on the basis of their ability to
accanpl ish the following set of enviromnental goals:
.
Perform necessary environmental site restoration
.
create no additional negative impacts upon air, surface water,
groundwater or soil quality.
create no impact upon neighboring properties.
.
.
Make the site aesthetically rore acceptable
Prevent or minimize the potential for hll1W1 contact with
waste materials after site closure is complete.
-------
23
Another criterion which was used was the time frame for implementation
and maintenance. The time frame for any remedy will ultimately affect
its cost and the potential for adverse environmental impact. Short-term
managment can be implemented; and long-term remedial actions usually
should be avoided based on economic and environmental considerations.
Remedial action methods which maximized short-term accomplishment and
minimized the long-term monitoring and maintenance work were favored.
A remedial cleanup program must be implemented and operated in a cost-
effective manner in addition to successfully addressing the environmental
concerns at the Highlands Acid Pit site. In considering cost-effective-
ness of the various technologies, the following costs were considered:
o Capital Costs
o Operating Costs
o Maintenance Costs
o Monitoring Costs
Capital costs and occasionally operating costs are encountered during
the implmentation phase of a remedial action program, but monitoring
and maintenance costs continue during the post-closure period. Monitoring
and maintenance operations can represent a substantial portion of a
remedial action strategy. The added costs for these operations should
be minimized.
The present worth method was utilized to evaluate the total cost of a
remedial action strategy over the design period. The design period and
discount rate used in the evaluation were 30 years and 10 percent, respectively.
An indepth discussion regarding the initial screening can be found on
pages 7-10 to 7-22 of the feasibility report and is summarized on table 6.
The alternative methods which were selected as most viable, during the
initial screening, to achieve the desired remedial action objectives
were then evaluated in detail in order to develop a basis for their
subsequent use in defining potential remedial action plans. The remedial
action methods selected for evaluation were:
o Site Management
o Infiltration Control (Cap System)
o Excavation with Off-site Disposal
o Waste Encapsulation
-------
I .;\
r.
fL,a1
,
'-
Selected lIethod.
, ....
.~
,. ....,
,...
=rr'D
'"
(II
"0
~
%
C
(II
d
z
..
In
(II
g
~
.(11
Site Management
InflitratiOD Ccmtrol
Excavation with OfflUe Dispoial
Waite Encapmlatlon
RCRA Equivalent Landfill On-Site
."...~
. I
.. .
......... ;
: ,
x
X
X
X
X
N
.,f::o
TABLE 6
REMEDIAL ALTERNATIVE METHODS
INmAL SCREENING RESULTS
Ground
Water.
Objective. Achieved
Surface
Water.
Z
Air.. ~
.!!Jected Method.
Waite Fixation
incineration
SoUl
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Reason lor Rejection
Extent and depth 01 waite prohibit In IItU fixation.
Variation In waste material compolltlon and organic compounds
make acceptable fixation technically difficult.
Waste removal with fixation and reburial resultl In exceulve envir-
onmental risk.
Low BTU values of waste and mixture with Inert materials prevent
-------
1'...'
I.. ;u
.... .J
-."
......' j
t..l.J
:8
I"
~ ' : ,'\
TABLE 6 (Concluded)
Land Treatment
Type 0' waste contaminants Ullsultable for blorec1amatioDe
Extenslye land area required.
1.0. BTU values and mixture with Inert materials prevent energy
recoyery.
Energy Recoyery
. Ja belDI achleyed at pre8eDt.
.. wm be achleyed by Implementlnl measures which focus on eoUs obJective.
=rrD
rot
'"
."
~
%
C
'"
...
u
Z
II-
~
'"
&
~
;;I
.'"
z
p
N
-------
26
Site specific applications for each of the measures were developed and
evaluated to clarify important features and identify any elements which
are inappropirate or unfavorable. Each alternative measure, was also
evaluated and described in terms of the screening parameters outlined
previously.
An indepth discussion regarding the detailed evaluation can be found on
pages 7-22 to 7-84 of the feasibility report and is stmnarized on table 7.
'!be site man~ement plan is the only method that does not achieve all
of the planning objectives when considered alone. '!here fore since the
site man~ement activities are required for any remedial measures of
the Highlands kid Pit, this method has been inchrled as Part of all
remedial action plans as shown in table 8. Waste encapsulation was rejected
in the final evaluation since it achieves the same objectives as infiltration
control at a much greater cost.
Based on the results of the above evaluation it was determined that the
Extensive Excavation Off-Site Disposal remedial method is the nest cost-
effective alternative. (See Recarmended Alternative Section for details
on selection).
O:mnunity Relations
(See attachment 1)
Consistency With Other Environmental Requirements
Other environmental laws were reviewed to establish baseline technical
requirements and determine if the reccmnended remedy met these
requirements.
The RCRA technical regulations (40 CFR Part 264) were reviewed to
establish baseline requirements and determine what canponents of the
reocmnended remedy did or did not ClCllply. In addition, an alternative
was developed in the Feasibility StlX!y that would fully canply with
RCRA regulatioos for construction,of a hazardous waste landfill. '!his
alternative was described in the previous section. '!he RCRA equivalent
landfill alternative on-site was about 397 percent oore expensive than the
reocmnended action and did not result in increased protection to public
health, welfare, and the environment. '!he rea:mnended off-site action,
alternative EEDSD, will canply with RCRA generator' transporter require-
ments, '!be proposed remedy will inclu3e a gro\mdwater nenitoring progrCltl.
'!he JOOnitoring program will be used to determine if future conditions
warrant additiooal remedial actions. '!his program will continue for at
-------
TABLE. ,
.
ALTERNATIVE RDtEDIAL METID)S
Dgr'AILID f.VAWATIOO RESULTS
Remedial Methods
Status
~asons for Rejection
Site Management
.
Site clearing/gra3ing, revegetation,
maintenance and 1OOI'litoring
Preferred
.
Surface water diversion
Rejected
Excessive costs, floodway encroachment,
incompatible with desired land uses.
Limited nm-off fran a3jacent areas.
.
Flood protection
Rejected
Infiltration Cbntrol
.
Multilayer cap-clay and membrane
seals
Preferred
.
Soil a:1mixtures, structural seals
Rejected
Technical uncertainties due to
cracking am deterioration
Excavation with Off-Site Disposal
.
Extensive excavat:ion off-site
disposal
Preferred
.
Limited excavation, off-site
disposal --
-------
. .
~,. ..J
L. .
. "
" ~
. .'.....,
.. J
. -..
TABLE 7' (Concluded)
Remedial Method.
Status
Reason for Rejection
ExcavatiOD with Off-Site Disposal (Cont'd)
o Excavation to clay layer
Rejected
Costs are six times that
of extensive excavation
alternative.
Waste Encapaulatlon
o Multilayer cap and clay liner
o SOU admixtures, structural seals
Preferred
Rejected
o Synthetic membrane bottom and
wall Dnen
Rejected
Technical uncertainties due to
cracking and deterioration
UnreUabllity under lite
hydrogeologic conditions and
type of waste materials
N
OJ
RCRA Equivalent LandfiU On-Site
o Excavation of all on-site
contaminated materials
Preferred
o Construction of landfill
on-slte above ground-water table
-------
Alternative
1. Infiltration
Control Cap.
2. EXtensive
EXcavation
with Off-
Site Dis-
posal (8
feet depth).
3. Limited
EXcavation
with Off-Site
Disposal (4-6
feet depth).
4. RCRA
Ekjuivalent
Q1-Site
Larx3f ill.
5. tb action.
Remedial ktion
Q)st ($1000)
Capital Present
tbrth
804
1,338*
TABLE 8 SUMMARY OF - ""DIAL ALTEmATIVES
Public Health
Chnsiderations
Minimizes direct
contact. Potential
hazard through
ingestion of c0n-
taminated fish if
washout of waste
occurs.
Eliminates public
health threat.
910rt term exposure
of ~rkers to waste
. during excavation.
sane as 1. Short
term exposure of
~rkers to waste
during excavation.
sane as 3.
Direct contact to
nearby residents
and recreational
users of river
complex. POtential
hazard through
ingestion of
contaninated fish.
Environnental
O:>ns iderat ions
Potential wash-
out of waste
into surface
water system
during flood
or subsidence
with possible
adverse impact
on aquatic life.
lDwest risk
of adverse
environmental
inpacts.
Sane as 1.
Sane as 1.
sane as 1.
Technical
Chnsiderations
Cap could be
severely eroded
during flocx1ing.
Straight-
forward.
Best reliable
technology. .
IDng term
reliability
in lD'1stab1e
environment
uncertain.
Sane as 3.
Difficult c0n-
struction con-
ditions. Poor
location for
ReM landfill
tbne.
Public
Qmnent
Unacceptable.
Highly
Acceptable.
Unacceptable.
Unacceptable.
Highly
Unacceptable.
Other
Annual
inspect ion/
repair of
cap. High
maintenance
cost.
Minimal
site
maintenance.
Minimal ..
site
maintenance.
Annual
inspection!
repair of
cap and re-
taining wall.
High mainte-
nance cost.
tbne.
* Infiltration control cost ~uld increase by $700,000 to $800,000 if long term flood protection facilities are incltrled
L.- ---.....-Ar. ___-A_-
2,407
2,540
1,637
1 ,770
9,443
10,609
o
-------
3() :
Since the site is located in the 100-year floodplain, the requirements
of Executive Order No. 11988, covering Floodplain Management, were
reviewed. It was concllXled that the proposed remedy will not creat~ a
sustantial risk to public health, welfare and the environment due to
the 100-year flood if certain measures are follOlft1ed. '!he responsible
goverment agencies will be contacted during the design stages to ensure
that their requirements and recarmerrlations are implemented.
Reamnended Alternative
Sectioo 300.68(j) of the National Contingency Plan (NCP) states that
the appropriate extent of remedy shall be determined by the lead agency' s
selection of the remedial alternative which the agency determines is
cost-effective (i.e. the lowest cost alternative that is technologically
feasible and reliable and which effectively mitigates and minimizes
danage to and provides adequate protection of public health, welfare,
or the environment). Based upon our evaluation of the investigation
and feasibility reports, EPA has determined and the State has agreed,
that the extensive excavation off-site disposal alternative meets the
NCP criteria. In addition representatives fram the Center for Disease
Control have reviewed and concurred with the recarmended remedy since
it would adequately alleviate any public health threat which may result
fran the site (see attactJnent 2). '!he following discussion describes
the recarmerrled alternative and the reasons for its selection.
FOr the extensive excavation off-site disposal alternative wastes would
be excavated to the groundwater level (about 8 ft) within the surficial
waste area. Based on the site investigation, this is the maximum depth
to which wastes were deposited. '!his excavation would renDVe approximately
19,,000 cubic yards of materials. If material is visually in evidence
anYwhere beyond the defined outer lateral limit of excavation, it will
be renDVed. Additionally, any soils excavated within the defined
lateral limits that can be demnstrated as uncontaminated will be
left on site to reduce transport/disposal costs. Wastes will be
transported by truck to a secure hazardous waste disposal facility.
'lhe excavation then would be backfilled with exmtOn fill. In order to
limit off-site migration of contaminants during construction tenp:>rary
berms around stockpiled waste areas will be constructed. Figures 9
through 11 show the inplementation of this alternative.
-------
~. :1
r~~
Ct~ ..,
'.. . .
,.' ..
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, ... ..J
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.. . i '
~
.. ".. ..
'i
~~ ..
~
-1-
-----
----------
8.
8hallow Gr... Wo,,,
Polentlomtt,lo ..,fOCI
-Id
SAND
"O"IZOffTAL IrA!
. -711
y
....
f
CLAY
ehESPEV, HUSTON 8 ASSOCIATES ,INC.
ENGINECIIIN(; . ENt'1RONllCNrAL CONSULrANrs
'I,ure 9
C,OIl-tlctlon Alonl lonlltudl S 81' 01' 89~
HI,hlond Aold Pit
EXTENSIVE EXCAVATION /OFF-SITE DISPOSAL
-------
""~"
l.i>.~
L "
J
tJ
L
--.'
~.. ,..
..
.
BACKFILL EXCAVATED AREA
'I
-0
-Id
Sh81108 "...81 ..,.
Po,..,...',lc I.,foc.
w
w
SAND
HO"IZONTAL .C.~
I I
Of..' 110
CLAY
e ESPEY. HUSTON 8 ASSOCIATES ,INe.
n EJIIlIllfEDt,. . EIWIIIDMENrAL CONWLrA""~
Cro.. - lIetlon Alan, lonlltutl. 9510 01' s.~
HI,hland Acid Pt,
'It.,. 11
EXTENSIVE EXCAVATION/OFF-SITE DlSPOIAL
-------
34 .
For the purposes of estimating costs, it was assumed that the entire
body of soils in the defined waste area, down to the water table, is to
be excavated and removed. The site investigation work indicated that
the soil/waste area is quite heterogenous and definition of extensive
quanities of non-contaminated sands is unlikely. However, the actual
construction activity will include such testing activities as required
to identify significant deposits of such non-contaminated soils. Such
soils would remain on site and will result in a lowering of overall
costs. Tables 8 and 9 indicate the costs associated with the remedial
action plans which were evaluated in detail (includes site management).
As mentioned earlier in this report certain site management measures
would be implemented regardless of the alternative selected. In the
case of the extensive excavation alternative the following site
management measures will be employed.
The site management methods provide for clearing the rounded surficial
waste area, shaping the area to fill depressions, and emplacing a
contour layer of common fill to achieve a three percent gradient.
Figures 12 and 13 show the recommended features. The fill will include
six inches of topsoil, that will be seeded, mulched, and fertilized.
A temporary site perimeter fence will also be installed to minimize
human intrusion during construction.
Maintenance for the site management method would consist of periodic
inspections, revegetation and erosion control. Since the site is
sUbject to flooding, it is projected that 10 percent of the site area
would require regrading and revegetation annually. Additionally, the
site will be mowed periodically.
As can be seen on Figure 12 groundwater monitoring wells will be
installed to monitor the shallow and deeper groundwaters. The
monitoring wells at the site will be checked and sampled quarterly for
the first year and annually thereafter. Six monitoring wells are
required, four of which will be new. To monitor the effectiveness of
the proposed alternative on groundwater remediation, various laboratory
analyses on key indicator parameters will be performed. Recommended
analyses, based upon contaminants found at the site include pH, specific
conductivity, TOC, TOX, phenols, benzene, toluene, methylene chloride,
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TABLE 9
ENGINEERING COSTS FOR DESIGN AND CONSTRUC110N SUPERVISION
I.
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Remedial Action Pia ConceptfDe81gn CODStruction
IDfllt.aUOD CODtrol Cap. $1 ZO,OOO-I50,000 $60,000-SO,000
Extenal.e hca.atlon - 110,000-ZZO,000 110,000-140,000
Off-Site Dllp08a1
Limited EKca.atlon - 150,000-180,000 80,000-100,000
Off-Site DIap08a1
RCRA Equlwa1ent On-Site 470,000-660,000 150,000-Z30,000
LandfiU
Total
$180,000-Z30,000
Z80,OO0-360,000
Z30,000-Z80,000
6Z0,000-S90,000
z
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SITE PERIMETER FENCE C Iltclu',' lit 8" ..a..,..)
Co...1t FlU ,Gra', CIft' CoItlo.r
SAND
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~ShoIIO. Waler Tabl.
Monitor W.II.
(llIelucl8d III all ..alur..)
HORIZONTAL SCALE
y
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n ENfJ,III££",. . E/lNIIIDME/IIT'AL t:rJIIISVLrAlllr~
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S!U. 01' 59. Highlandl AcldPil
FI,.,. 12
SITE MANAGEMENT
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38
Tables 10 and 11 show the detailed cost breakdown for the proposed
alternative (extensive excavation off-site disposal and site management).
'!he extensive excavation with off-site disposal (EEX:>SD) alternative was
selected as the recarmended alternative fran the list of plans on Table
8 of this docrment. EPA, has determined along with the State that the
EEX>SD alternative best ~lies with Section 300.68(j) of the NCP
mentioned earlier.
'Ihe infiltration control cap alternative was not selected based on
several reasons. '!he major negative environmental factor associated
with this plan resUlt fran all the wastes remaining in place. '!bis is
a very significant point since the site is located in a very dynamic
h}'drologic environnent. Due to the location of the site within the
river floodplain, flooding is likely several times during the 30-year
design period. A flood event could cause erosion of the cap and in
turn result in a deposit of wastes in the San Jacinto River system.
Flood protection facilities would reduce the risk of cap failure or
dCIItIaJe during those storm events, however, a high potential would still
exist for waste migration. In edition, should subsidence continue, the
likelihood of failure for this system is increased. '!he costs associated
with this alternative, wen the flood protection facilities are inclt.rled,
equal $2,138,000, wich is less than the prQp)Sed EEDSD plan. lbwever,
due the problems mentioned above, EPA and the State do not believe the
cost savings are justified since there is less protection in the long-term
to p.Jblic health, welfare, and the environment.
'!be major problem with the limited excavation with offsite disposal
(I.En;D) alternative is its lower reliability wen canpared to the
EEDSD plan since sate of the wastes will remain onsite. IDng-tetm
changes in the existing environmental setting could result in a
higher potential for exposure of the waste materials to the envi-
ronment. Q)ntinued subsidance, for instance, could permit the water
table to rise into the remaining waste body, increasing the discharge
of contaninants to the groundwater and a:ljoining surface water bodies.
Excavation to a depth .of only 4 to 6 feet is questionable, since only
part of the original waste materials ~e renoved. '!be costs of this
alternative are also lower than the proposed EEDSD Plan (See Table 7).
Ibwever, due to the probl~ mentioned above, EPA and the State again
do not believe the cost savings are justified since there is less
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h ESPEY. HUSTON & ASSOCIATES, INC.
TABLE 10
REMEDIAL METHODS: EXTENSIVE EXCAVATION WITH
OFF-SITE DISPOSAL
Item
Total
Cost
1.
hc..ate Wute Material
TUD8port Wute Material Off-Site
Di8pose of Wute Material Off-Site
Backf"ill hca.adon Area
Subtotal
S 64,500
2047,500
903,000
150,500
S1,365,OOO
2o.
3.
4.
5.
6.
0gerhead/PrOfit, IDdirec:t Field Labor
Costs (2.5%)
Subtotal for Capital COlt
341,500
7.
SI,706,500
8.
Contingency for Capital Cost (205%)
4206,500
TOTAL PRESENT WORTH
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h ESPEY, HUSTON & ASSOCIATES, INC.
TABLE 11.
REMEDIAL METHODS: SIrE MANAGEMENT
Item
Total
Colt
1.
S 35,000
MobWzation/Demobilization ad Site
Serricel
2. Control Sun'eymg
3. Clear ad Grub General Site Area
.. Grade/Contour General Site Area
5. Off-Site DilpOial of Milcellueoua Solid
Wute
6. Topaoil Coyer I:D8tallation
7. Monitor Wen Conltruction
8. Site Perimeter Fence
9.
Subtotal
10. OYerhead,lProfit, IDdirect Field Labor
Coats (ZS%)
11. Subtotal for Capital Colt
12. Contingency for Capital Colt (25%)
13. TOTAL CAPlT AL COST
1.. Mmlitor Wen SampliDl/ADalyai8 Program.
15. Site MaiDteD8Dce.
16. Subtotal for MaiDteDace ad Monitoring
17. Contingency for MaiDtenuce ad Monitoring
(25";')
18. TOTAL MONITORING AND MAINTENANCE
COST
TOTAL PRESENT WORTH
12,000
6,000
37,500
10,000
.0,000
8,000
26,500
S175,000
44,000
$219,000
55,000
S274,000
.5,000
61.500
S106,500
S 26.500
S133.000
$407,000
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41
The last alternative evaluated against the proposed EEOSD Plan is the
RCRA equivalent onsite landfill. There are several technical feasibility
as well environmental effectiveness problems associated with this plan.
Major difficulties are expected in excavating such a large volume of
waste and constructing a landfill in a secure fashion. Due to the
quanities of waste to be handled, adjacent properties will probably be
needed as temporary storage areas. Storm events during construction
will impact this alternative more than any of the others, since more waste
will be exposed to the environment.
As part of the RCRA landfill alternative, a slurry wall will need to be
constructed. Difficulties will probably be encountered during the
installation of the slurry wall. Since the excavation area includes
nearly all of the site, the slurry wall will be constructed on the edge
of the site adjacent to the San Jacinto River, Clear Lake, and the
sand pit. Minimal space will be left for equipment movement to install
the barrier. Soil stability may also be a problem on the edges of the site.
The long-term stability of the RCRA landfill on the Highlands Acid Pit
site is uncertain since rising and falling of groundwater poses potential
problems for the integrity of the bottom landfill liner. Subsidence
could also significantly impact the stability of the landfill due to
groundwater intrusion and flood elevations. In addition, a flood
event could cause a failure in the landfill cell resulting in a deposit
of wastes in the San Jacinto River system. Flood protection facilities
would reduce this impact. However, the potential still exists since the
wastes will be left on-site.
The estimated costs of this plan are $10,609,000 plus $890,000.00 for de-
sign and construction management, which is $8,599,000 more than the pro-
posed EEOSD alternative. This plan was rejected due to its many negative
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42
'!he no-action plan will not accooplish site objectives. Surficial
soils are contaninated and exceed the criteria for health and toxicity
limits. Hunan contact with the contamination is likeiy, as evidenced
by past intrusions and garbcge disposal activities and adjacent
recreational uses. '!hese contaminants will continue to migrate off-
site throtr:Jh wind and surface water erosion. Infiltration throlJJh the
site will also continue to leach contaminants into the grOlmd water.
Based on site investigation data, ground water, surface water, and air
quality objectives are presently met. Cbntinued erosion and slbsidence
of the site, however, could negatively impact ground waters, surface
water and air quality. Extensive erosion of surface soils could expose
additional wastes, thereby pralDting volatilization of contaninants,
decreasing air quality. 910uld the site continue to subside, grOlmd
water will rise into and will begin to migrate throlJJh the wastes,
increasing the discharge of contaminants to the grOlmd waters and
adjoining surface water bodies. Contmnants will also be released
mre frequently to surface waters during flood events. '!he area of the
site is located in a very productive estuary which is extensively fished
and used for other recreational uses. '!he increased released of
contaninants during flooding events and continued subsidence could
adversely affect the water quality near the site. '!he concentration of
benzene or other contaminants could increase above the WJC in adjacent
water bodies near the site, thus adversely inpacting their current
uses.
'!be unstable environment at Highlands Acid Pit, due to its l~ation in
the 10-year floodplain and history of subsidence, preclll3es on-site
remedies and the no-action alternative.
Of all the remedial action plans evaluated, the EIDSD has the lowest
risk of additional adverse environmental ~cts in the long-term. All
contaminated materials demonstrated as currently or potentially affecting
the envircnnent are renDYed in this plan. POtential exposure of waste
left onsite due to flooding, slbsidence, or major storm events would be
eliminated.
'!be total capital cost of the EEDSD Plan is estimated at $2,407,000
with annual mnitoring and maintenance cost estimated at $14,100.
'lhe present worth of the annual 'IOOnitoring and maintenance cost equals
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43
Operation and Maintenance
Projected operation and maintenance activities will inclLrle a nonitoring
well sampling/analysis program and site maintenance for a 30-year
period. Six nonitoring wells will be sanpled/analyzed quarterly for
the first year and annually thereafter for the fOllowing contaminants:
Manganese
Sod i \JtI
Ca:U \JtI
Olrani \JtI
Lea:}
Sulfate
Phenol
Benzene
'lbluene
Methylene Chloride
'roC
'roB
pH
Specific Chnductivity
Site maintenance will inclLrle nowing, replacement of 10% of topsoil per
year, and reseeding of 10% of the site per year.
Present worth costs for operation and maintenance activities (O&M) are
presented in and Table 11. Annual O&M costs are $14, 100.
'!he recanmend level of EPA findings for O&M activities is 90% of total
O&M costs for a period of 1 year after the completion of construction.
'!he state has agreed to accept all remaining O&M costs for a period of
at least 29 years. '!he state can guarantee the funding on an ongoing 2
year period.
Schedule
Appr0\7e Remedial Action (sign ROD)
June
1984
Award O:>operative ~reement Amendment
for Design of the Approved Remedy
June
1984
Start Design
August 1984
October 1984
O:mplete Design
Award Remedial Action O:>operative ~reement
AmerXbnent for Construction of ApprO\7ed Remedy
Start Cleanup
N:>vember 1984
Complete Cleanup
December 1984
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ATTACHMENT I
Community Relations
The community relations objectives at the Highlands Acit Pit site focused
on infonming interested officials and citizens of progress at the site.
The Remedial Investigation and Feasibility Stu~ and the press release
announcing the public comment period were placed in nine repositories in
the HighlandslHouston area ten days before the beginning of the comment
period. A press release was issued by the Region jointly with the Texas
Department of Water Resources (TDWR) to notify officials and citizens of
the public comment period and public meeting on the recommended alterna-
tive. Courtesy telephone calls were also made to elected officials and
environmental groups prior to the initiation of the comment period. The
public comment period ran from April 30 to May 21. 1984.
A public meeting was held by the Region on May 8. 1984. at the Highlands
Junior High School in Highlands. Texas. William Hathaway. Deputy Director
of Air and Waste Management Division. moderated the meeting. Also present
were Stephen Romanow. Project Engineer for the Region. Charles Faulds.
Project Engineer for TDWR. and George Buynoski. Superfund liaison from
the Centers for Disease Control. Mr. Hathaway presented the background
on the Superfund program. the Highlands site. and the recommended alterna-
tive. Mr. Faulds presented a summary of the technical aspects of the in-
vestigation and feasibility phases. Mr. Buynoski fielded comments and
questions relating to potential health effects from the site. Approxi-
mately seventy people attended the meeting. including one elected official.
Sfx people read statements. all of which were generally supportive of the
Region's efforts at the site. The general topics of concern raised by the
audience at the meeting included:
Technical details of the recommended alternative and the investigation
and feasibility studies.
Health effects from the site
Possibility of conducting a health study in the area around the site
Impact of the site on groundwater and organisms (e.g.. fish. shrimp)
caught for consumption
Potential air pollution from the site during construction
Potential deposition of waste in neighborhoods while hauling the
waste aw~ from the site
Continued operation and maintenance at the site after the reme~
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2
'lhese topics were covered in great detail by Mr. Hathaway, Mr. Faulds,
and Mr. Buynoski during the meeting. A copy of the transcripts fran the
meeting is available for review. '!he meeting lasted approximately t\«>
and a half hours. .
Two written statements have been received to date. Q1e is a statement
fran an adjacent property owner expressing satisfaction with the remedy.
'!he other is an anonym:>us p:>stcard, also expressing satisfaction with the
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Date
From
~ubject
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ATTACH~1nlT 2
DEPARTMENT OF HEALTH & HUMAN SERVICES
Public Health Service
Centers for Disease Con+rnl
Memorandum
. March 23, 1984
George Buynoski ~
Public Health Advisor, CDC
Highlands Acid Pit - Remedial Action
Steve Romanow
Superfund/Operations Section
As requested, staff at the Center for Environmental Health have reviewed
the remedial measures proposed for closing out the Highlands Acid Pit
si te.
The plan, which basically involves the excavation and removal of the
acid waste, should adequately alleviate any potential public health
problems that might result from the site.
The sampling data evaluated indicates that waste migration off the site
is not happening at an alarming rate. Elimination of the source should
virtually curtail any future migration of hazardous substances. Once
the obvious contamination is removed it is apparent that some residual
concentrations will remain in the soil in/around the pit. Based on
an analysis of past migration patterns, it wouTd appear that these
contaminated soils would not be considered a health concern. As an
added precaution the addition of a neutralizing agent e.g. a Few inch
layer of lime, prior to adding the final fill, would further minimize
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