United Slates
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R01-86/019
September 1986
4 EPA
Superfund
Record of Decision
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A
.
TECHNICAL REPORT DATA
rPltast rtacJ Instructions 011 tht rtvtnt IHfryt co,""lttlflIJ
1. RII"O"T NO. 12. 3. RECIPIENT'S ACCESSION NO.
EPA!ROD!ROl-86/0l9
.. TITL.E ANO SUITITL.I 5. FIIEPORT OATE
SUPERFUND RECORD OF DECISION Spntember 25 1986
Kellogg-Deering Well Field, CT a. PERFORMING OFilGANtZATION COOE
7. ...uTMO"ISI 8. PERFORMING OFIIQANIZATION REPORT NO
t. PERFORMING O"GANIZATION NAME "'NO AOOAESS 10. PAOGA...M EL.EMENT NO.
". CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME ANO AOOFIIESS 13. Type OF REPOFIIT ANO PERIOO coveFilEO
U.S. Environmental Protection Agency ",;,.,::01 Rcm
401 M Street, S.W. 1.. SPONSOFilING AGENCY cooe
~...'
washington, D.C. 20460 800/00
15. SUPI"L.EMENT"'RY NOTES
18. A8STR"'CT
The Kellogg-Deer ing Well Field site, also known as the Smith Well Field, is a
'lOO-acre public supply well field in southwestern Fairfield County, along the western
bank of the Norwalk Rive r, Norwalk, CT. The well field is owned and operated by the
NOr'ooJal k First Taxing District water Department (NFTD) serving approximately 45,000
people. The pr imary source of public water supply to the NFTD is surface water from
four reservoirs, with ground water as a secondary source. In 1975, trichoroethene (TCE
was discovered in the ground water. Between 1975 and 1980 the Connecticut Department 0
Environmental Protection performed onsite sampling and initiated investigations at
several local industries since the well field is being impacted by contamination outsid
the site boundaries. The potential primary source of ground water contamination is
located to the eastern edge of the site area. Contaminants are migrating with the
ground water from areas of high concentration toward the well field. The movement is
partially influenced by the pumping of the production wells. TCE is the primary
contaminant of concern. Other identified contaminants include: PCE, 1-2-DCE, '11ethylen
chloride, xylen.es, and benzene.
The selected remedial action for this site involves air stripping of the contaminate
ground water .and subsequent discharge into the existing conventional water treatment
plant and distribution system; and air and ground water monitoring. The estimated
capi tal cost associated '..,ith this remedY is'$69.751 with annual O&M cnc::ts of $52.336
17. o<:EY WOFIIOS ANO OOCUMENT ANAL.VSIS
a. OeSCAII"TORS b.loeNTIFleRS,OPEN ENoeo TEFIIMS c. COSArl Fleld.Group
Record of Decision
Kellogg-Deer ing Well Field, CT
Contaminated Media: gw
Key contaminants: VOC s, TCE
,
18. OISTFilIBUTION STATEMENT 19. SECuRITY CL.ASS ,T!lIsRrpon/ 21 ,
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i< S C~ () Ri)O F D F: CIS Ii):--i
RE~~nIAL ~LrERNATIV~ S~LECTION
(iPF::RABLF: UNIT 1
Site
Kellogg-Deering Well Pield
Norwalk, Connecticut
Documents Reviewed
1 am basing my decision primarily on the following documents
describing the analysis for the cost and effectiveness of
the first operable unit remedial alternatives for the
Kellogg-Deering Well Field.
- Kellogg-Deering Well Field Remedial Investigation (NUS
Co~po~ation, April, 1986)
~... .
- Kellogg-Dee~ing Well Field Operable Unit 1 Feasibility Study
(NUS Co~po~ation, June 1986)
- Comments fro~ the Connecticut Depa~tment of Health Services
(July, 1986)
- Summa~y of Remedial Alte~native S6tection (September 1986)
- Responsiveness Summary (September 1986)
Description of Selected Remedy
Bring into ope~ation existing ai~ stripping facilities to re-
move volatile organic compounds from the contaminated g~oundwater
feeding the Kellogg-Deering Well Field. The stripped water will
be discha~ged into the existing conventional water treatment
plant and the distribution system. The Operable Unit serves to
assure the reliahle supply of safe, ~otable wate~ to the public
dependent on the well field.
Declarations
.
.
Consistent with the Comprehensive Environmental Response, Com-
pensation, and Liability ~ct of 1980 (CERCLA), and the National
Contingency Plan (40 C.P.R. Part 300), I have determined that
Air Strlpping at the Kellogg-Deering Well Field is a cost-effective
remedy that provides adequate ~rotection of public health,
welfare, and snvironment. The State of Connecticut has been
consulted and agrees with the approved ~emedy. In addition,
the action will require future operation and maintenance
activities to ensure the continued effectiveness of the re~edy.
These activities will be considered part of the approved action
and eligihle for Tr~st ~und monies up to 90% of the cost for a
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EPA will undertakp. an additional ~9merlial Investig~tion/Feasihility
Study to further characterize current and additional potential
sources of contamination, and to evaluatp. rp.medies to address
such sources. IE additional remedial actions are determined to
be necessary, a recor.d of decision will he prepar8d for approval
of the future remedial action.
t':4 .., C'
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Oace
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Michael R. Deland
Regional Administrator -
, ,
-
Region I
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KElLOGG-DEE~ING WELL ~[ELD
SITE LOCATION AND DESCRIPTION
The Kellogg-Deering Well Fielrl Site, also known as the Smith
Well Field, is a 10 acre puhlic supply well fielrl in southwestern
Fairfield County, along the western bank of the Norwalk River in
Norwalk, Connecticut. The site is locate~ 4,000 feet south-
southwest of Routes 7 ann 15 interchange.
T~e Kellogg-Deering well field is being impacted by conta-
mination from sources outsirle of the well field. Under CERCLA,
a facility is coextensive with the associated contamination;
thus, for legal purposes, the Site in fact includes the up-
gradient plume that is migrating towards the well field.
The well field is owned and operated by the Norwalk First
Taxing District Water Department (NFTD) serving approximately
45,000 people. The primary source of public water supply to
the NFTD is surface ~ater from four reservoirs. Reservoir water
is blended with well field water at varying ratios depending on
reservoir storage and distribution system location. The well
field consists of four production wells and a conventional treat-
ment plant contributing between 15 and 35 percent of the NFTD
water supply. The four wells are known as Layne 1, Layne 2,
Deering 1, and Deering 2.
Groundwater from the well field area is presently -used by
the NFTD for public water supply. Surface water is the
principal source of water supply for the NFTD; hence, the
aquifer is not a sole source one. The appropri~te groundwater
class, for the aquifer underlying the well field, under the EPA
Ground Water Protection Strategy is II-A.
Land use varies in the area. Immediately (within 100 feet of
the well field property line) west, north, and south of the
well field are residential areas. Across the river, east of the
well field, is a landfill not presently in use. The area east of
the landfill and Deering Pond is part residential and part indus-
trial. Within this area there is an industrial park, a cemetery,
and a series of comercial husinesses mixed with light industry.
The Kellogg-Deering well fielrl ann the immediate area east across
the river are within the 100 year flood plain of the Norwalk
Rive r .
SITE HISTORY
The southern acre~ge of the Kellogg-Deering well field site
has heen owned by the NFTD since approximately 1935. Several
lots weie added in 1936. The northern 7 acre tract was purchasG1
in 1964. The first of the four production wells, Layne 1, was
installed in 1955. The other three were install~rl as follows:
Deering 1 in 19~5, Dee~ing 2 in 1960, and Layne 2 in 1975.
Trichlnroethene (TC~) was niscovered in the groundwater in
1975. The NFTD hegan analyzing yroundwater sa~ples from the ~~11
Eield in that year. Between 1975 and lqqn the Connecticut nep~r~-
,"e:1t of E'1vironrnental Pri)tection (DJ::P) perf;)r~ed severed inspect-
i"ns 3:lrl ::;"'\r:1~lin'Js <"'It t-,1,<" Kell"'jg-i)eeri'1.;;j sit~ and initiated ~,,-
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gated to the N~tional Priorities List (NPLI in 1984.
Efforts to determine the extent of contamination, which began
with the DEP investigations, continued with the EPA Remedial
Investigation. Previous studies showed that the areas north,
west, and south of the site could be discounted as potential
contaminant sources. For the pu~pose of characterizing" the
groundwater contamination plume a study area was developed to
include the well field s"ite and the area east of the site (see
figure 1). -
All production wells and several monitoring wells in the
study area were sampled between July 1984 and August 1985.
EPA's National Contract Laboratory Program (CLP) analyses detec-
ted TCE in three of the four production wells. The highest TCE
concentration (86 ppb) was detected in Layne 1. Historical data
showed a maximum TCE concentration of 600 ppb on Layne 2 in
1980. Appendix A to the RI report presents historical data for
all production wells~"
In May 1981 a redwood slat aerator was installed on Layne 2
by the NFTD. The aerator consistently removes 65 percent of the
volatile organics in the groundwater. A composite sample of well
field water after treatment and prior to blending with reservoir
water was analyzed in 1984. The composite excluded Lay~e 1 water
which was normally pumped to waste to reduce contamin~nt levels
on the other three wells. It consisted of samples at the point at
which wells Deering:l (raw), Deering 2 (raw), and Layne 2 (aer-
ated) combine. TC~ levels in the composite averaged 10 ppb. It
was estimated that well field water was blended with reservoir
water at a ratio ranging from 1:3 to 1:5. The Superfund Imple-
mentation Group, Center for Environmental Health, Centers for
Disease Control r.eviewed the composite data and conclurled that
it did not appear to be an imminent and substantial endangerment
to public health at the time. The EPA thus concluded that no emer-
gency measures were required at the time.
In 1984 the daily production of the surface water system was
5.1 mgd while its safe yield was 5.25 mgd. The NFTD determined
that more of the well field safe yield had to be available for
public supply in order to guarantee that the surface system's
safe yield would not be exceerled. Hence, the NFTD installed in
1985 an air stripper on Layne 1, which is potentially the best
yielding well, hut the most contaminated one.
Layne 1 is the deepest of the four wells, intercepting the
upgradient plume without the full henefit of dilution from
the Norwalk River, and therefore showing higher levels of con-
tamination. As mentioned hefore, such pluMe is legally consi~-
ered to he part of the site. Further discussion regarding the
contaminant plume follows below in the Current Site Status
Section. .
The stripper. is rated by the manufacturer as heing 99 percent
efficient, hut not yet in operation due to rrobleMs with a hold-
ing tan~. The tank is expected to be repairad during the Eall of
1986. The stripper is capahle of tre~ting water froM any of the
four production wells. A diagram of the NFTD water supply syst~m
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1"'.,
'9..
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1"'1-
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-STUDY AREA BOUNDARY
~KELLOGG.DEERING SITE
STUDY AREA
KELLOGG-DEERING SITE.
NORWALK, CT
. PriIT:ar~' Source .:'\rea
Scale 1.' = 500'
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PRODUCT10N
WELLS
RESfRVOIRS
WELL FIELD SUPPl Y
DEERING 2
DEERING 1
LA YNE 1
LAYNE 2
REDWOOD
SLAT
AERATOR
(lns~lIed
1981)
SURFACE SUPPLY
NORWALK
. .
SCOTn
SU MCiO
SAfE YIILD
IROWN
GRUPES
TREA TMENT
U MCiO
SAFI YIILD
Chlorin.tion.
fluorid.tion.
'.
sodium (
hydroxide.
phosphate
STACK AERATOR
(Under construction)
"% remov.1
efficiency of volatile
org.nics
,.'
fiLTER PLANT
Aer.tion. activated urbon. pr. &
post-chlorination. alum
floccul.tion. Mttling. rapid Mnd
filtration. uustic soa.
polyphospMte. lime & fluorihtion
FIGURE 2
KELLOGG-DEERING SITE
WATER SUPPLY SYSTEM
NORWALK FIRST TAXING DISTRICT
CONTRIBUTES
1S - n% of
total supply
NORWALK FIRS T
TAXING
DISTR.O
SUPPL Y
(1984: 1.901 MG)
CONTRIBUTES
'5-85% of
tot.1 supply
~~~@
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CURRENT SITE STATUS
The population at risk is the approximately 45,000 people
served hy the NFTO. Environmental concerns are limited to
contamination of the unconfined aquifer in the well field and
study area. There is no evidence of impact to surface water
bodies. Benthic and aquatic org~nisms do not appear to be at
risk.. No other welfare concerns have been identified. Primary
routes of exposure associated with this site include ingestion
of drinking water, and inhalation through showering.
Several chemical substances were detected throughout the study
area. Most of them were organic volatiles dissolved in the ground-
water. Types of substances, levels detected, and frequency of
detection are presented in Table 1. The total amount of con-
tamination at the site is difficult to approximate due to the
nature of the site and the type of contamination. TCE, tetrachlo-
ethene (PCE), and l;2-dichloroethene (1,2-0CE) were detected at
the highest concentrations and frequency. TCE is the primary con-
taminant of concern due to concentration and frequency of detec-
tion. Several monitoring wells east of the well field showed high
levels of TCE contamination. The highest TCE concentration detected
in the .groundwater was 100,000 ppb at approximately half a mile
east of the well field. Other contaminants of concern detected
in the study area include PCE, 1,2-0CE, methylene chioride (OCM),
l,l,l-trichloroethane, henzene, and xylenes.
Maximum TCE concentrations detected at the well field, during
the RI, were 86 ppb on Layne 1 and 64 ppb on Layne 2. Historical
maximum TCE concentrations range from 300 to 600 ppb at the well
field (see Appendix A to the RI report). Other chemicals detected
at the well field include OCM, benzene, 1,2-0CE, and chloroform
(chloroform was detected in trace amounts).
Of the chemicals detected at the well field, TCE and OCM are
classified as prohable human carcinogens. Benzene is classified
as a human carcinogen. The current estimated incremental life-
time carcinogenic risk of the groundwater at the well field is
1.8 x 10(-4) for adults. This corresponds to a 1.8 in 10,000
chance that ~ continously exposed aiult would develop cancer
during his lifetime due to exposure (through ingestion and inha-
lation) to the chemicals at the concentrations detected at the
well field. Other hazardous properties are descrihed on pages
7-5 to 7-12 of the RI report; nevertheless, at the concentrations
detected at the well field, o~ly carcinogenic risk are of concern.
Concentrations are projected to i~crease hy a factor of tan at
the we 11. fie 1 d 0 v era peri od 0 f t h i r t y yea r s due tom i g rat i on 0 f
the contaminant plume. This projected increase ~ould raise the
risks associated with the groundwater at the well field by one
Jrder of magnitude if no additional measures are taken to control
or mitigate such an increase.
Most chemicals letected in the Kellogg-Deering study area can
u n.j e L;J 0 ana. e r 0 h i c de 'J Lad 1 t i () n i n t '1 e sub sur f .3. C eat v -3 r y i n g rat e s .
The ultimat~ ~reakdown products of TCE are chloroethane and vinyl
:':;/1l')drJe. 'vinyl chl.Jrije ha.s been detected in the study .::irea. The
che"ic:ds :ietected in the study =trea may '1ot he reused or recycled.
C'>i1tanin.-1tion <2xtei1:!s vertic."!lly tfn-ough the overhurden and
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TABLE 1 Page 1 of 2
CONTAMINANTS DETECTED
KELLOGG - DEERING SITE, NORWALK, CT
GROUNDWA TER SURFACE WA TER SEDIMENT SUB-SURFACE SOIL
01 H(IIOII lOH('NIAAIIUH OtIHf!OIlll (011(1 II rIA 11011 01lHIIOII (OHU...IRAflOH DllHtlON lUNltNINAllON
CHEMICAL CONTAMINANT latQUllln RANc..I U9 t fRtQUtNl Y lI..tII"t "9,1 fatQUllln AAN<:.t U'J f flU QUI Nt y NANltt u-. I
Ct IlORINA TED AUPHA TICS
T RICHLOROETHENE 83 / 95 2-100,000 2/5 4-8 3/26 2-41
IETRACHLOROETHENE 30/95 1-1.500 1/26 2
ff
I, 2 - DICHLOROE THENE 61/95 1-4,000
1,1 - DICHLOROETHANE 4/95 }2-38
1,1,1 TRICHLOROETHANE 2/95 3-4 1/26 1
1,1,2 TRICHLOROETHANE 1/95 630 1/26 1
ME IHYlE NE CHLORIDE 18/95 1-900 4/5 7-9 4/26 1/1,~OO
CHLOROFORM 3/95 8-600
VINYL CHLORIDE 2/95 1}-136
~_QNOCYCLIC A~OMA TICS
'BENLENE 7/95 I') LbO 1/26 4
TOLUENE 10/95 2-240 18/26 3 -1,200
XYlENlS( TOTAL) 8/95 3-590 1/5 2 1/5 8
ETHYlBENZENE 2/95 72-40 -. 1/ 26 2
'-
PHENOL 1/95 72 NA NA NA NA
U DICHLOROBENZENE 1/95 4 NA NA NA NA
"UONES
AC[ lONE 11/9'> 114,500 3/26 19 - 26
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TABLE 1 Page 2 of 2
CONTAMINANTS DETECTED
KELLOGG - DEERING SITE. NORWALK. CT
GROUNDWATER SURFACE WATER SEDIMENT SUB.SURFACE SOil
Dllft 1I0IiI {ONCINIRAJlON UIIHllOh lOH
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into bedrock. Hocizontally, the contamination extends throughout
the study area; however, the study area boundaries might not
coincide with the exact extent of contamination. Further studies
are needed in order to better characterize such extent.
The well field is located in a south trending buried bedrock
valley. Depth to bedrock ranges from approximately 100 feet in
the well field area to less thari 10 feet about half a mile east
of the well field. Overburden and bedrock are hydraulically
connected. Soils in the area are typicallly sandy. Generally
the soils are well drained with moderately rapid permeability
(2-6 inches/hour). Very rapid permeabilities (>20 inches/hour)
have been observed in some areas. General groundwater flow is
to the west, southwest, and northwest. The Norwalk River is not
a barrier to groundwater flow; groundwater passes underneath the
river to the production wells during periods of pumping.
The potential primary source area of groundwater contamination
is located at the ea1;.tern edge of the study area shown in Figure
1. TCE concentrations in the groundwater drop steadily down-
gradient from the area of highest TCE levels, until increases
in TCE levels are noted in certain downgradient areas (see sec-
tion 4.5.5 of the RI). The causes of these rises in TCE concen-
tration. cannot be determined based on the available data. Two
potential explanations for the anomalous increases have been
identified:
. Secondary sources of TCE contamination may be located in the
downgradient areas.
. The anoMalous increases in TCE concentrations may reflect
'slugs' of more highly contaminated groundwater resulting
from separate releases of TCE into the environment.
Cont~minants are migr3ting, with the groundwater, from area~
of high concentr~tion toward the well field. This movement is
partly influenced by the pumping of the production wells.
ENFORCEMENT ANALYSIS (See Appendix I)
ALTERNATIVES EVALUATION
The response actions at this site have been phased into opera-
I)le units. An operable unit is a discrete part of the entire re-
pense action that decreases a release, threat of release, or path-
way of exposure. The first operahle unit involves the well water
treatment dnd distribution system (i.e. the human pathway of
ex~osure). The second o~erahle unit will serve to further charac-
t .-= r i z e and / 0 c ide n t i f Y pot e n t i a 1 sou r c ear e a S .3 n d tog a the r s u f -
Eicient inf')rll1ation to ,ietermine the necessity f.:)r and propose.-j
ex~~nt of reCTlerlial ,3\:1:10n to 3ciriress such source arer'ls.
'"::'he t=>ri:rnry ohje.::tivA .)f the K.~ll()gg-Deering well field first
'}:' e r t !> 1 A U :1 i I: i ~ to [) r () t .-, ': t t h P. P u h 1 i c by ass u r. i n <] C\ r. elL .'l h 1.. ."
.:;u)~)Lf)F. S,f8, .L)'jt:=thlcN.'\ter. L") the pllhl Lc currently .4epend2nt
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on the well field.
A Remedial Investigation/Feasihility Study (RI/FS) was unde~-
taken, for the EPA by NUS Corpo~ation, from June 1984 to June
1986 to determine the nature and extent of the threat presented
by the release and to evaluate proposed remedies at the site.
INITIAL SCREENING
The following seven alternatives were developed in the FS
report for consideration:
o No Action
o Air Stripping
o Air Stripping plus Air Emissions Treatment
........
o Activated Carbon Treatment
o Air Stripping plus Activated Carbon
o Air Stripping plus Activated Carbon plus
Air Emissions Treatment
o Expansion of Surface Water Treatment Plant
These alternatives were initially screened using the broad crite-
ria specified in section 300.68 (g)(1), (2), and (3) of the
National oil and Hazardous Substances Pollution Contingency Plan
( NCP) :
(1) Cost;
(2) Acceptable Engineering Practices; and
(3) Effectiveness
Two of the seven alternatives were eliminated during initial
screening. The two alternatives included air eMissions treatment
as part of the remedy. Volatile emissions expected from air
stripping are less than those requiring t~eatment as specified
by State of Connecticut ~egulations hy approximately one order
of magnitude (see Appendix A to the FS report). The two alterna-
tives were screened out on the hases of Acceptable Engineering
Practices and Costs. These alternatives do not meet the accept-
a~le engjneering crit~rion since air emissions do not require
t~eatment to meet puhlic health and environmental objectives.
In addition, the extr~ cost of ai~ emissions treatment is not
justifiable where the treatment does not provide significantly
yr~dter protection.
DErAILED EVALUATION
The reMaini.ng fiv~ alt2rnatives were analized i.n detail ,:::on-
si:;tent 'Nit;' the six (i-'li) ev,11uatioll crite~ia in Section JO().
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ing evaluation factors:
(i) RefineMent and specification of the
alternative in detail.
(ii) Detailed cost estimation.
(iii) Engineering implementation, reliability,
and constructability.
(iv) An assesment of the extent to which the
the alternative is expected to effectively
prevent, mitigate, or minimize th~eats to,
and provide adequate protection of public
health and welfare and the environment.
(v) Recyclability of waste and application of
innovative, or alternative technologies.
...
(vi) Adverse environmental impacts.
Further. rliscussion of these criteria is presented in t:he NCP. The
above criteria were consisered for analysis under th~ following
sections or headings in the FS:
(i)': Section 3.
(ii): Cost Evaluation.
(iii): Technical Evaluation.
(iv): Public Health Evaluation and
Institutional Evaluation.
( v ) :
The contaminants detected at the site
are not reusable or recyclable. No
innovative, or alternative technologies
were identified for the first operable unit.
Therefore, it was inappropriate to consider
criterion (v) in the rletailerl analysis of
alternF\tives.
( vi) :
Environnental I~pact Evaluation.
For the purpose of this document, criterion
(vi) will be consirlered together with in-
Eor~ation relating to criterion (iv) unrler
the heariing of Public Healt~ and Environ-
nental Concerns.
,; s U;-'1 mar 'I of the results of t f[ e de t ail e 1 evaluation 0 E3 1 t 8 r n a -
ti~es Eollows helow.
Descripti0n oE Alternatives
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NO ACTION (Alternative 1)
The no action alternative would involve no new treatment facil-
ities. The present redwood slat tower Aerator on Layne 2 would
remain in operation as well as the conventional water treatment
system (chlorination, flouridation etc.). The packed tower air
stripper on Layne l'would not .~e beought into service. The
cueeent sampling and analysis peogeam would be expanded to in-
clude' appeoxirnately seven monitoring wells located in the un-
confined aquifer on the eastern side of the Noewalk River.
Monitoeing chemical contaminants (mostly volatile oeganics) on
the east side of the eivee would allow foe eaely detection of
possiole deterioeation in the watee producing aquifee: hence,
it would provide time to take coerective action at the well field.
AIR STRIPPING (Alternative 2)
~... .
For this alternative the stripper on Layne 1 would be brought
into seevice. This steippee has been designed a~j it is guaran-
teed to eemove 99% of the chloeinated hydrocaebons (e.g. TCE)
and q8% of the monocyclic aeomatics (e.g. benzene) in the ground-
water up to 600 ppb (the historical maximum TCE concentration
detected). As part of the FS,the air stipper's design specifica-
tions weee eeviewed to confirm the .99% efficiency rating given
by the manufacturer. The aie steipper is capable of treating
water from any of the four production wells. The water distribu-
tion system demand for well water is less than the rated capacity
of the production wells: hence, the steipper may not need to
operate continously. To accomodate the disparity between system
de~and and production rate, a large holding tank (750,000 gal)
has been installed. Following installation, cracks developed in
the tan~ rendeeing it unusahle and thus peeventing the operation
of the air stripper. The aie stripping alteenative includes the
holding tank repair and a monitoring program similar to the one
Ear the no action alternative with additional testing of the
tr8atment system's perfoemance. Aie monitoring is also included
in ordee to confiem (oe not) that air emissions treatment is
not required.
A.IR STRIPPI;~G PLUS ACTIVATED CARBON (.I\lternative 3)
This alteenative would add ar'1 activated carhon treatment system
to alternative 2. The cArhon treatmer'1t system would ~e installerl
to handle treated water pumped fro:n the haloing tar'1k. The pri-
mary function of the activateo carhon system would be to pro'v'ide
a safety h~ckup to accommorlate potential fut~re contaminant ~x-
2u~sinns w~ere the concentrations of TeE may exceeo 600 pph,
'",hich is the 'iesigned perEorMance limit Eor the ne..... air str-ippec.
Tn satisE'{ desi..Jn criteri;'\ for the system characteristics at 1-,'),.>
:.z.:>ll,)q.;J-1)2,~ring well Eield, six 12-Eoot-diameter vessels '",itio.
12-foot-,4eep c"rhon 0815 'wo'llci ':;2 re.~uired. This alt,?rnative
',,'.') ill Ii d 1 :; 0 i n c 1 ;.1 d e a rr1 () nit') r. i n 9 p r '')':1 r a 1'1 a s d L S c u sse 0 i r'1 ;:d t ern J -
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1 2
l\ v
.u
EXPAND SURFACE WAfER TREATMENT SYSTEM (Alternative 4)
This alternative addresses the option of installing additional
surface water treatment capacity in an amount sufficient to re-
place the system demand provided by the Kellogg-Deering well
field. To accomplish this alternative, a new water treatment
plant functiona1lyequiv31ent- to the present surface tre3tment
plant would be requiredr This system would utilize conventional
water treatment technologies li~e chlorination, sand filtra-
tion, and other typical treatment technologies. To install a
new surface water treatment plant, a new influent supply line
would have to be built from the reservoir system to the plant.
Similarly, a new treated water supply connection would have to
be installed from the new treatment plant to the existing sur-
,face water treatment facility. The existing reservoir safe
yield is S.25 mgd. The daily production of the existing surface
water system in 1984~'was near this capacity (approximately 5.10
mgd). The evaluation of well field production indicates that the
safe yield of the reservoir would be exceeded if a new surface
water treatment plant were constructed or the existing plant
expanded. '
ACTIVATED CARBON TREATMENT (Alternative 5)
Under this alternative an activated carbon treatment system
would be used exclusively to remove contaminants from the
groundwater (i.e. neither the stripper on Layne 1 or the aera-
tor on Layne 2 would be used).' Discharges from all wells would
be routed to a series of activated carbon filtration columns.
To satisfy design criteria for the system characteristics at
the well field, twelve l2-foot-diameter vessels with l2-foot-
deep ca,rhon beds would he required. A monitoring program would
also be part of this alternative.
Cost Evaluation
[~ 300.68(h)(2) (iil1
Cost summaries, including present worth analysis, for the five
alternatives are shown in Table 2. Present worth calculations
for future costs are based on a 10% discount rate. Future costs
would be incurred primarily in the operation and maintenance of
the remerly for an assumed 30 year period following remedial
construction. Based on present worth analysis, alternatives 1
and 2 have the lowest costs among the alternatives. The cost
Eor altecnatives 1 and 2 are of the same order oE magnitude.
Alternatives 3, 4, and 5 have costs one order of magnitude higher
than alternatives land 2. Alternative 4 is the ~ost expensiv~
followed hy 5 and the 1.
Technical Evaluation
r~ 3nn.68(hl(~) (iii)]
~ltern~tive 1 - Since ther~ 3re no new treatme~t f~cilitics 35
p ,,,\ r t 0 f t f! i ~ a 1 t i~ r n a t i "e t h 2 r \~ are not e c h n i c alE act 0 r s toe v a 1. -
U.:1 t~ . The 0 ~ li issue t () cons ide r is the 10 C =! t ion of m 0 n i to!::" i n 9
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'-
. .
TABLE 2
COST SUMMARY KEL8OGG-DEERING WELL rIELD
Di~ect Capital Costs
No.1
No. 2
No.3
No.4
No. I)
Low Base High
12,043 36,495 45,619
40,311 69,751 87,189
1,271,096 1,715,232 2,144,040
"..' 2,441,594 3,487,991 4,534,388
2,293,619 3 , 058 , 159 3,822,699
?
Alte~native
Annual Ope~ating & Maintenance Costs
A1te~native Low Base High
1 6,461 ',: 19,580 24,475
No.
No. 2 6,461 19,580 24,475
No. 2 (YR-15 only)* 34,729 52,836 66,045
No. 3 114,347 346,506 433,133
No. 4 301;,349 437,642 568,933
No. 5 137,122 415,520 519,400
Present W:>~th Analysis
Alternative
Low Base High
No. 1 74,Ono 222,000 278,000
No. 2 109,000 263,000 329,000
Nr). 3 ~,355,000 4,998,000 6,247,000
No.4 5,344,000 7,633,000 9,924,000
No.5 3,592,000 6,994,000 8,743,000
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14
)
.0
need to be relocated due to the potential construction of Route
7. The same is true of all alternatives involving monitoring.
Alternative 2 - Air
sites as well as in
this alternative is
stripper is already
pect~d.
stripping has been widely used at Superfund
industry; thus, it can be concluded that
reliable and easy to implement. As the air
-i n place -no cons truct ion problems are ex-
Alternative 3 - As discussed
a very reliable process with
be said for activated carbon
~o installation problems are
for alternative 2 air stripping is
proven performance. The same can
treatment as it is commonly used.
expected.
Alternative 4 - Since the safe yield of the reservoir system
would be exceeded if this alternative is implemented, the
alternative is unreI'iable.
~lternative 5 - See alternative 3 evaluation of activated carbon
treatment.
Public ,Health And Environmental Concerns
[300.68(h)(2)(iv)&(vi)]
The following were considered as part of the Public Health And
Environmental Concerns Evaluation:
A. Carcinogenic Risk
B. CERCL~ Compliance with Other Environmental
Statutes and Expected Adverse Environmental
Impacts
A. Carcinogenic Risk
The incremental carcinogenic risk for the five alternatives is
listed in Table 3. This table shows the added risks associated
with the chemicals detected at the well field which are either
human carcinogens or probable human carcinogens (i.e. TCR, OCM,
and benzene). The tahle lists groundwater risks after treatment
by each of the methods described in the five alternatives. Sur-
face water supplies (alternative 4) are not impacted by the con-
tamination at the site; thereEo~e, they were not considered in
this analysis.
~lte~native 4 exhihits the lowest incremental carcinogenic
risk: however it has been stated that this alternative is tech-
~ically unfeasi~le. The remaining alternatives can be ranked in
orde~ of increasing risk as follows: 3<2<5<1. The reduction in
cancer risk achieved by alternative 3 is one order of magnitude
better than 2 which is in turn one order of magnitude hetter
th-:'\n 5 and 1.
Contaminant concentrrttions rtt t~e well field are expected to
lncrease ten fold over a period of thirty years. Carcinogenic
r.i s k s w 0 U 1
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. .
TABLE 3
INCREMENTAL LIFETIME CARCINOGENIC RISKS
Alternative No.
Risk after treatment
1*
6.4 x 10(-5)
,...,
2
2.1 x 10(-6)
3
3.2 x 10(-7)
4**
5
3.1 x 10(-5)
*
The ~isk of untreated groundwater is 1.8 x 10(-4).
** Surface water supplies are not linpacted by th8 contamination
at the site: the~efore, they were not considered in this
analysis.
Note:
Dilution is not considered in this analysis. Carcinogenic
risks were calculated assuming a worst case scenario under
~hich the population served by the NFTD becomes 100% dependent
on well field water. It is also assumed that all four wells
would exhihit the current highest levels of contamination
detected. Such scenario could conceivably arise under a severe
drought, or should the reservoir treatment system fail or if
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l~
. Q
B. CERCLA Compliance with Othe~ Enviromental Statutes and
Expected Adve~se Environmental I~pacts.
"
The NCP states that as pa~t of the netailed evaluation of
alternatives, the alte~natives shall be evaluated in terms of
whethe~ they attain o~ exceed Applicable, Relevant, And
Approp~iate Requi~e~e~ts (ARA~s). With respect to this site,
no such ARARs we~e identified. Neve~theless, the NCP also
states that ~elevant Federal crite~ia, adviso~ies, and guid-
ance and State standards shall be conside~ed during the eval-
uation process. For this site, these include:
. Connecticut Air Hazard Limiting Values
. Connecticut Drinking Water Regulations
. National Drinking Water Advisory Council (NDWAC)
recommendations
. Proposed Maximum Contaminant Level (PMCL),
Recommended MCL (RMCL), and Proposed-Recommended
MCL (PRMCL) .
. Suggested Adjusted Acceptable Daily Intake (AADI)
connecticut Air Hazard Limiting Values apply only to alterna-
tives 1, 2, and 3 as these are the ones involving air contaminant
emissions. As mentioned hefore, volatile organic emissions expec-
ted are less than those requiring treatment as specified by
State of Connecticut guidelines.
The National Drinking Water Advisory Council (NDWAC) recommends,
as a health goal for carcinogens, a risk level of 10(-6); neverthe-
less the NDWAC states that 10(-5) would be an appropriate target
to strive for as an upper limit for risk.
Federal and State drinking water guidelines are shown in Tahle 4.
Analysis for CERCLA compliance with other environmental statutes
was based on current site conditions. The RMCL for carcinogens or
suspected ca~cinogens is zero: therefore no alternative (except 4)
meets the RMCL when considering well field contaminants.
Alternative 1 fails to meet PMCL for TCE. It satisfies all
other guidelines. Adverse environmental impacts other than the
current groundwater. contamination are not anticipated under the
no actioll alternative. No evidence of impact on surface water
bodies i~ evident. Benthic and aquatic organisms do not appea~ to
be at risk in either the site or the study area east of the sit~.
Alternative 2 meets all guidelines. Adverse environmental
impacts are not anticipated under present and projected long
t~rm site conditions. An analjsis of contaMiDan~ ~elease as a
result ~f volatile chemic3l emissions from the air stripper
i~rlicatAs that ambient air concentrations will not exceed ap-
~licahle State guirlelines (see Appendix A to the FS report).
~lternative 3 meets or exceeds av~ilahle stan,jards. The ex-
~ected impacts from this alternatives are the same as for alt~r-
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::;
. .
TABLE 4
EXPOSURE CRITERIA AND GUIDANCE 80R WELL FIELD CONTAMINANTS
FEDERAL (All values- in ppb)
Chemical RMCL PMCL PRMCL MOl*
TeE 0 5 260
DCM 0 ~...' NR -- 350* *
1,2 OCE NR 70 NR
Benzene 0 5 25
* Not con~irlering carcinogenic effects and assuming 100% contribution
tram drinking water.
** Life tUne Health Advisory assuming 20% contribution from drinking
water.
STATE (All values in ppb)
Chemical
Limit
TeE
25 (expected to go down to 5)
OCM
25
Benzene
1
1,2
OCE
NR
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H
.'
Alternative 4 meets all standards. The adverse environmental
impacts associated with this option are related to the destruction
of habitat. Approximately 32 acres of habitat would be destroyed
as part of the required construction. The contruction of the new
plant, however, is not expected to have an appreciable impact on
native species of animals. It is not believed that any endangered
species exist in the area. .
Alternative 5 fails to meet PMCL for TCE, but satisfies all
ot he r ' gu idel ines. The -expected impacts unde r th is a 1 te rna t i ve are
the same as for alternative 1.
None of the five alternatives would have any impact on the 100
year flooa plain of the Norwalk River.
Innovative And Alternative Technologies [300.6R(h)(2)(v)]
As mentioned before, it was innapropriate to consider this
criterion in the det~iled analysis of alternatives for the first
operable unit of the Kellogg-Deering Well Field Site.
ADDITIONAL DATA
The time required to implement each alternative is presented
in Table 5. The no action alternative is essentially in place
with the exception of the implementation of an expanded monitoring
plan. The time needed to implement such plan is expected to be min-
nimal. Alternative 2 can be implemented in twelve weeks as only
repairs are neeeded to bring the system into operation. Alterna-
tives 3, 4, and 5 would take longer as design, bidding, and
construction would be required. Alternatives 4 and 5 would take
over a year to implement while alternative 3 would take 36 to 44
weeks.
COMMUNITY RELATIONS (See Appendix II)
CONSISTENCY WITH OTHER ENVIRONMENTAL REQUIREMENTS
in
Consistency with other environmental requirements is discussed
the Detailed Analysis of Alternatives section above.
RECOMMENDED ALTERNATIVE
Section 300.68 (i) of the NCP states that the appropriate extent
of remedy should be determined by the lead agency's selection of a
cost-effe~tive remedial alternative which effectively mitigates and
minimizes threats to and provides a~equate protection of puhlic
health and welfare and the environment. Consistent with the NCP and
based on the evaluation of cost and effectiveness of each altern~-
tive, the comments receive~ from the puhlic and the Connecticut
nepartment of Health Services, Alternative 2 has been determined
to he the cost-effective and most envi~~nmentally sound alternativ~.
, The r.ecommenderl alternative is consirjered an operahle unit
r"2medial action consi:;tent wit~ the NCP and EPA policy. This
o~er3hle ~nit re~erlial a~tion for air stripping treatment of well
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. .
TABLE 5
TIME REQUIRED TO IMPLEMENT REMEDY
KELLOGG-DEERING SITE OPERABLE UNIT NO. 1
Al terna t i ve Number
Activity 1 2 3 4 5
Design Engineering N/t>. N/A (1) 12-14 weeks 26-30 weeks 26-30 weeks
Bidding N/A 6 weeks 8-10 weeks 8-10 weeks 8-10 weeks
.....'
Construction N/A 6 weeks 16-20 weeks 16-20 weeks 16-20 weeks
N/A 12 weeks 36-44 weeks 50-60 weeks 50-60 weeks
NOTES:
(1)
New Air Stripper is already constructed.
Storage tank must be repaired.
t'bt Applicable
N/A
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2n
. .
su~ply of safe, potable water to the public dependent on the well
field. The recommended alternative provides for packed tower
aeration treatment for 1,750 gpm of contaminated groundwater.
The treatment system will he 99% efficient in the removal of TCE,
the contaminant of most concern. The unit's removal efficiency
will provide water at the 10(-6) incremental lifetime cancer
risk level. The alternative s.at'isfies all appropri(}te Federal
and State criteria and standards for the contaminants detected
at the well field. In addition, the alternative requires proper
monitoring of. both the treatment system's performance and the
migration of contaminants toward the well field.
The direct capital costs for the recommended alternative are
$69,751.' These cost do not include design and instal~ation of the
air stripping unit as the NFTD has already incurred such expenses.
They include repairs necessary in order to bring the air stripper
into operation, and capital costs associated with the monitoring
progr(}m. Annual ope~ating and maintenance (O&M) costs are $52,836.
Of this amount, S19,580 correspond to the required monitoring
program. The remaining O&M costs represent the expected repairs
needed for the storage tank after fifteen years of operation.
The present worth cost of the recommended alternative is $263,000.
The ,recommended alternative is technically feasible, provides
adequate public health protection (i.e. satisfies all guidelines),
and has low environmental impact. It achieves these 90als at a
present worth cost :of S263,000. Table 6 summarizes, for compar-
ison, the detailed' analysis of alternatives. Below is a brief
discussion of why the other alternatives were not recommended.
Alternative 1 is technically feasible, has low environmental
impact and costs essentially the same as the recommended alterna-
tive. However, it does not provide adequate public health protec-
tion and fails to consider projected increases in contaminant
concent~(}tions at the well field.
Alternative 3 is technically feasible, has low environmental
impact and exceeds available guidelines to protect public health.
However, the cost of this alternative is well over 10 times the
cost of the recommended one.
Alternative 4 provides adequate public health protection, but
it is technically unreliable. In addition its costs exceed those
of alternative 2 by several million dollars, (}nd it has some neg-
ative environmental impacts associated with it.
Alternative 5 is technically feasihle and has low environmen-
tal impa~t. However, it fails to provide adequate public health
protection and its costs are also over 10 times those of alter-
nat ive 2..
For the reasons listed ahove, alternatives 1,1,4, and 5 have
not heen cecommended.
OPERATION AND MAINTENANCE
The projected O&M activities requir~d to ensure the effective-
ness of the remedy il'1clude a monit:)rin(J l)rogram, repdirs to the
st")r::l(Je tdnk, al'1d perio'Hc inspections of the air stripping unit.
::'he on-':;it,~ "1init')r'in,] pr:-')'Jrarn ..;ill consist of the following:
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TABLE h
CCMPARISON OF REMEDIAL ALTERNATIVES KELLOGG-DEERING SITE
OPEAARLE UNIT 1
Present ~vironmental Time to
Alternative No. ~rth Techn ical Risk (Mult) Public Health* Impact Implement
1 222,000 F 6.4 x 10(-5) 00 low
--"
2 263,000 F 4.0 x 10(-6) YES low 12 weeks
3 4,998,000 F 3.4 x 10(-7) YES low 36-44 weE
4 7,633,000 U YES low 50-60 weE
5 6,994,000 F 3.0 x 10(-5) 00 low 50-60 weE
F: Feasible
U: Unfeasible
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22
first week of operation. If the unit ~roves to be perfJrming
adequately it will be used for public water. supply. Adequate
performance implies co~pliance with the available Federal and
State criteria and standards.
b) after (a) is completed, weekly monitoring of raw and treated
water for a period of three months will be conducted. At the
end of that period the mOITitoring program will be evaluated
to determine the need to continue monitoring on a weekly
basis. Monthly samplings should be expected for the first
year of operation.
c) quarterly sampling of the production wells not in use for pub-
lic water supply. If in use, weekly sampling will be required.
It is required that any well water used for public water sup-
ply is first treated by the air stripper on Layne-I. Excep-
tions to this requirement must be approved, prior to imple-
mentation, by the EPA. Any water used for public supply must
satisfy availabl&'Federal and State criteria and standards.
d) yearly inspections of the air stripper unit to ensure proper
functioning.
e) during trial and operation of the air stripper, stack and/or
ambient air monitoring will be required to verify that
emissions are not violating applicable standards or guidelines
and are not causing any threat to public health.
The off-site monitoring program includes quarterly samplings
of seven monitoring wells on the east side of the river. Moni-
toring will allow for early detection of possible deterioration
of the water producing aquifer. Such early detection will give
appropriate time to take any needed corrective action at the
well field. The wells to be monitored are 6M, 6D, K2A, K28,
K-8(or MW-3), 15, and l5R as shown in Figure 3-1 of the RI. Some
of these may have to be relocated due to construction of Route
7. Coordination with the Connecticut Department of Transportation
will be required. In addition, monthly monitoring at four points
in the distribution system to be approved by the EPA will be
required for the first three months of operation. Need for addi-
tional monitoring will be evaluated at the end of that period.
It is expected that the storage tank will require additional
repairs after fifteen years of oper.ation.
Prior to the operation of the stripper, the air stripper unit
must be approved by th Connecticut Department of Health Services.
It is anticipated that all O&M activities will be conducted
by the NFTD under an appropriate agreement with the EPA to he
prepared in coordination with this document. The estimated annual
O&M costs are 552,836 for a period of thirty years.
FUTURE ACTIONS
Additional studies will be required at the Site as part of
the second operahle unit. Such sturlies will serve to further
chardcterize and/or identify potential source areas and to
gather. sufficient inEor~ation to determine the necessity Eor
and pr'Jpos0d extent of reinediC'll action to a:-:dress such sour.ce
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~
. .
APPENI?IX II
COMMUNITY RELATIONS
KELLOGG-DEERING WELL ~I~LD SITE
NORWALK, CONNECTICUT
--.
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. .
COMMUNITY RELATIONS
Community interest in the Kellogg-Deering Site began in 1975 ~hen
contamination in the wells was first detected. Public interest
began to increase ~~ September. 1983 when the Kellogg-Deering Site
was listed on the National Priorities List (NPL). By early 1984,
the Connecticut Citizen Action Group (CCAG), a statewide organization ~
involved in consumer and environmental issues, began contacting
Norwalk residents to organize a group of citizens, called the Water-
force, with concerns about the well field contamination. On July 11,
1984 the EPA helo a public meeting to discuss the RAMP for the
site. Approximately 65 residents attended, including members of the
Waterforce. Since the summer of 1984 little public action has
occurred at the site.
A public meeting to describe the RI and to respond to citizens'
questions was held on May 22, 1986 at the Norwalk Public Library.
Approximately 30 persons attended, including citizens, potentially
responsible parties, and representatives of the local. Water Board.
A second informational meeting was held on July 17, 1986, at the
same location, to discuss the FS. On July 31, 1986 a' public hearing
was held at the same location to record comments by the public, in-
cluding potentially responsible parties. Comments were given by one.
~rivate citizen and by three ~otentially responsible parties. Written
comments from some of the same parties and additional parties were
received during the remainder of the public comment period. These
comments and EPA's responses are included in the attached responsive-
ness summary. In addition, the comments are summarized below. The
public comment period on the RI/FS was open from July 17, 1986 to
August 7, 1986.
The State ot Connecticut Department of Health Services favored packed
tower aeration, GAC filtration, and aeration with GAC filtration
rather than expansion of the existing conventional treatment facilities,
activated carbon treatment mOdules, production well management, and
purchasing trom an adjoining water supply. One potentially responsible
~arty (PRP) stated a ~reterence tor tinal implementation of the
existing air stripper. Several PRPs ptoposed purchasing water trom
an adjoining supply. One PRP stated that air stripping with activated
carbon treatment, surface water treatment expansion, and activated
carbon treatment were more expensive, but not more protective of
public health, than air stri~ping. One PRP stated a preference for
turthet'consideration of the "No Action" alternative. Several PRPs
objectee to having tHO operable units, citing that this would not
result in a com~rehensive, overall solution.
A citizen was concerned that there might be technical oversight in the
-------
~2
.
to determine the need to continue monitoring on a weekly
basis. Monthly samplings should be expected for the first
year of operation.
c) q~arterly sampling of the production wells not in use for pub-
lic water supply. If in use, weekly sampling will be required.
It is required that any well. water userl for public water sup-
ply is first treated by the air stripper on Layne 1. Excep-
t~ons to this req~irement must be approved, prior to imple-
mentation, by the EPA. Any water used for public supply must
satisfy available Federal and State criteria and standards.
d) yearly inspections of the air stripper unit to ensure proper
functioning.
e) during trial and operation of the air stripper, s~ack and/or,
ambient air monitoring will be required to verify that
emissions are not violating applicable standards or guirlelines
and are not caus\0.g any threat to public health.
The off-site monitoring program includes quarterly samplings
of seven monitoring wells on the east side of the rrver. Moni-
toring will allow for early detection of possible deterioration
of the water producing aquifer. Such early detection will give
appropriate time to take any needed corrective action :at the
well field. The wells to be monitored are 6M, 6D, K2A, K2B,
K-8(or MW-3), 15, a~d 15R as shown in Figure 3-1 of the RI. Some
of these may have ~o be relocated due to construction of Route
7. Coordination with the Connecticut Department of Transportation
will be required. In arldition, monthly monitoring at four points
in the distribution system to be approved by the EPA will be
required for the first three months of operation. Need for addi-
tional monitoring will be evaluated at the end of that period.
It is expected that the storage tank will require additional
repairs. after fifteen years of operation.
Prior to the operation of the stripper, the air stripper unit
must be approved by th Connecticut Department of Health Services.
It is anticipated that all O&M activities will be conducted
by the NFTD under an appropriate agreement with the EPA to be
prepared in coordination with this document. The estimated annual
O&M costs are $52,836 for a period of thirty years.
FUTURE 'ACTIONS
Additional studies will be required at the Site as part of
the second operable unit. Such studies will serve to further
characterize and/or identif.y potential source areas and to
gather sufficient information to rletermine the necessity for
and proposerl extent of remedial action to arldress such sourC8
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o
COMMUNITY RELATIONS RESPONSIVENESS SUMMARy
KELLOGG-DEERING SUPERFUND SITE
NORWALK, CONNECTICUT
INTRODUCTION
. This community relatfons responsiveness summary for the Kellogg-Deering
site documents for the public record concerns and issues raised during
remedial planning, comments r3ised durinb the comment period on the remedial
investigation/feasibility study, and the responses of EPA to these concerns.
The responsiveness summary is divided into the following sections:
Section 1. Overview. This section discusses the site history and EPA's
proposed alter~tive for remedial action.
Section II. Back2round on Community Involvement and Concerns.
section provides a brief history of community interest and
raised during remedial planning activities at the
Kellogg-Deering Site.
This
concerns
Section III. Summary of Major Comments Received Durin2 the Public Comment
. Period and the EPA Responses to the Comments. Both written and oral
comments on the remedial investigation/feasibility study are provided.
EPA responses to these major comments are also provided.
Section IV. Remaining Concerns. This section describes remaining
. community concerns that EPA should be aware of in conducting the
remedial design and remedial action at the Kellogg-Deering Site.
I~ addition to the above sections, Attachment A, included as part of this
responsiveness summary, identifies the community relations activities
conducted by the EPA during remedial response activities at the Kellogg-
Deering Site.
OVERVIEW
The Kellogg-Deering Site is a public supply well field located along the
western bank of the Norwalk River in Norwalk, Connecticut. The primary source
of water to the Norwalk First Taxing District (NFTD) is surface water,
however~. the production wells contribute between 15 and 35 percent of the ~rTD
water supply. The primary environmental concern at the Kellogg-Deering Site
is the contamination of groundwater. Trichloroethylene (TCE) was discovered
in the groundwater ~t the well field in 1975. Subseque~t investigation
-------
~he re~edial investigation verified ~hat the source(s) of contami~acion are
east or northeast of the well field. The water treatment and distribution
system are now referred to as Operable Unit ~1. The potential source areas
are termed Operable Unit #2. Rather than waiting for additional investigative
studies to fully define the source area(s), a remedial investigation (RI) and
a feasibility study (FS) was conducted to evaluate remedial alternatives for
reducing contaminants ~~ the well field.
alternatives considerea include:
The
o
o
o
o
o
Alternative 1
Alternative 2
Alternative 3
~
,: Alternative 4
.. Alternative 5
(No Action)
(Air Stripping)
(Air Stripping Plus Activated Carbon Treatment)
(Expand Surface Water Treatment System)
(Activated Carbon Treatment)
--.
BA~GROmm ()}If COMKDlfITY
IRVOLVEMD'T A!fD COIiCEUS
Community interest in the Kellogg-Deering Site began in 1975 when
contamination in the wells was first detected. From 1975 to 1983, the State
and private parties investigated the site extensively to define' the problem
and identify sources of contamination. Puring this period, the State health
department, the city health board and the city taxing district worked together
to coordinate public information for the community. Public attention
regarding the site began to increase in September 1983 when the
Kellogg-Deering Site was listed on the National Priorities List (NPL), making
it eligible to receive funds for cleanup under the Superfund Law. In late
1983/early 1984, a local group of citizens known as the Waterforce became
active in monitoring the EPA cleanup plans for the site. While a number of
different concerns were expressed by members of the Waterforce and other
residen~s during the remedial planning activities at the site, a majority of
these concerns were related to the groundwater contamination problem at the
site.
These concerns and how the EPA addressed these concerns are described below.
1.
~any residents have been drinking the water since 1975, when
trichloroethylene (TCE) was first discovered in the well field,
concerned over the potential health effects from the cumulative
to TCE. .
and are
exposu re
EPA Response: A health study to assess the impacts of previou~
contaminant exposure LS impractical since TCE and the other contaminants
found are quickly metabolized and excreted from the body.
,
Res i. den t 5 '../ a 11 t t: 0 !< now -..h a t: 1 e 'I e 1 S 0 f con tam i n ant s are l nth e wa t e r 3. n,~
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c.
EPA Response: The current TCE level is 3 parts per billion ppb (after
blending), which is below the Connecticut Department of Health Services
TCE limit of 25 ppb (after blending). The excess cancer risk presented
by consumption of this water at these TCE levels is not a health hazard
requiring immediate action though EPA has evluated remedial action to
mitigate long term exposure.
3.
Members of the yaterforce and' other citizens wanted the EPA to recognize
their concern that a~ immediate activity remedy was necessary at the
site.
EPA Response: In response to this concern, the EPA resampled the
production wells and sent the results to the Center for Disease Control
in 1984. Test results did not warrant any immediate ~es~nse actions.
About that time, the Norwalk First Taxing District WaterUCommission
approved plans to construct an aeration tower to remove contaminants from
the water supply. . In February 1985, acting independently from the EPA,
the Water Commis,s.ion awarded a contract for construction of an air
stripping unit and storage tank. The air stripper is expected to be
operational in 1986.
Comments raised during the Kellogg-Deering Site public comment period are
summarized below first for the Remedial Investigation (RI) ph~se then for the
Feasi~ility Study (FS) phase. The comment period was held from July 17 to
August 7, 1986 to receive comments on the feasibility study.'
SUMMARY OF PUBLIC COMKERTS RECEIVED DUIIIfG PUBLIC
COHMBRT PEIIOD AIm AGDCY RESPOIifSBS
Concerns Regarding tbe Re8edi.l Investigation
1.
A potentially responsible party consultant commented that the RI report
does not provide information concerning the quantity of TCE discharged
into groundwater within the study area, nor does the report attempt to
assign percentages of the total volume of TCE in groundwater within
the 'study area to different possible source areas. The commentors
calculated that approximately 1500 gallons of TCE had been
discharged within the study area, and concluded that this relatively
low volume was characteristic of several small discharges rather
than a single source. They also commented that the TCE found in
ar'eas downgradient of the primary source area identified in the RI
Report could not have migrated from the RI/FS identified source
area, based on the commentor's groundwater model (see Comment No.3,
below) .
EPA Response: Per the National Contingency Plan (NCP), the RI/FS
process ser'les the purpose of gathering sufficient information to
~eter.mine the necessity for and proposed extent of remedial aceion.
-------
the beginning of the investigation) and in particular for the first
operable unit such information included:
a)
nature, type, concentrations, and frequency of detection of
contamination
b)
c~rcinogenic" Fisk associat~d with the contamination detected at the
we 11 head
c)
current data on surface system and well field use and capacity
d)
current guidelines and standards for the protection of public health
and welfare, and the environment
Quantification of TCE releases and allocation of percentages of TCE
volumes in groundwater to potential source areas were not needed to
determine the ne~"ssity for and proposed extent of remedial action for
the first operable unit of this site.
After review of the data, however, EPA disagrees that the volume of TCE
discharged (estimated by the potentially responsible party consul-
tant to be approximately 1500 gallons) is characteristic of several
sources rather than one source. This quantity of TCE co~ld have come
from one or several sources. The relatively low discharge, however, more
strongly support~ the one source scenario than a multiple source
scenario. The possibility of multiple secondary sources in addition to
the primary source was stated as a part of the RI Report.
EPA disagrees with the application of the modelling effort used by the
commentor to support "."-.' conclusion that TCE found downgradient of the
primary source area identified could not have come from the source area.
The variables used in the commentor's model did not correspond with
actual field data (further discussion of the modelling effort is
contained in the EPA response to Comment No.3). Additionally, the
commentor's analysis of groundwater flow from the identified source area
shows that TCE from the source area could migrate throughout the study
area, to the well field.
2.
The comment was received from a potentially responsible party consultant
that the RI Report did not present an analysis of ground water flow paths
from the site property, or from other parts of the study area. The
consultant concluded that the TCE found downgradient of the source area
could not be attributed to the source area. ~~ also concluded that the
TCE.found downgradient of the source area was from other sources and that
this TCE was responsible for the well field contamination.
;::PA ~esDonse:
analysis, both
di.sag::oees '.Ji.th
The RI Report does present a groundwater flow path
in the RI and FS text and in several figures. EPA
:::-:e cone hs lO[1 that the TCE EOIj[1d downgrad ient 0 f the
]::o~a c~~ld ~ot je attributed to the source area, while
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Q
overburden and bedrock indicates that groundwater migrates from the
primary source area through the study area towards the well field, (as
did the RI). The commentor's discussion of groundwater flow within
fractures in the bedrock underlying the study area is oversimplified in
view of the known subsurface geology and unrealistic as it does not
incorporate field verified fracture orientations and intersections data
collected during the RI.
3.
The comment was re~eived that the model used in the RI Report was
. unrealistic in scope and too narrow in focus. Exception was taken to
some of the input values used. The commentor modelled TCE migration
using alternate input values, and concluded that TCE from the primary
source area identified in the RI Report could not have reached beyond
Plattsville Avenue at this time.
EPA Response: The objective of the model used in the RI was to determine
the "worst-case TCE contamination level at the well head" scenario. The
.~.
model was then used to evaluate the maximum risk possibl~ if well water
went untreated. The input parameters used were based on actual field
data, and represent the most accurate values currently available. The
model presented by the commentor was used for different objectives and
input values were used which were not supported by field data or
observations. The commentor's model assumed groundwater flow through low
permeability till deposits where actual flow was through.high
permeability stratified drift deposits, or in some cases, through
bedrock. The input values used by the commentor for groundwater
migration rates'were much lower than actual values, leading to a much
slower groundwater migration rate then predicted in the RI Report which
used field generated data.
4.
. The comment was received that TCE spills upstream of Deering Pond could
have migrated into the pond and settled to the bottom of the pond, where
the TCE would eventually migrate to groundwater and be the Source of TCE
contamination to the well field and to monitoring wells adjacent to the
river. The comment was also made that small TCE spills into the river
could flow to the well field, resulting in well field contamination that
has been found.
EPA Response: EPA feels that the likelihood of TCE spills which may have
settled into Deering Pond being the source of TCE to the well field or
nearby monitoring wells is very low. Historic sampling data has shown
that Layne 1 and Layne 2 are consistently the most contaminated wells in
the well field. These wells are the furthest of the wells from Deering
Pond. The Deering wells, located much closer to the ponds than the Layne
wel}s, consistently pump water ~ith much lower TCE concentrations, which
is the opposite of what would be expected if one or both ponds was the
~ource of TCE to the well field. The TCE found at monitoring well als~
~Lose ~o Deering Pond. and they consistently yielded very low
~oncenc~3ci0n9 of TCE in groundwater, this scenario seems unlikely. I:
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locations 9 and 6 is most likely from a SOurce area upgradient of the
wells, rather than downgradient. The possibility of TCE in surface
waters flowing past the well field being the source of the contamination
in the well field is also unlikely, as there are 11 years of data showing
relatively consistent levels of TCE in the well field, with virtually no
TCE being found in adjacent surface waters over that time period. The
consistent presence of TCE in the well field suggests a steady discharge
to groundwater instead of an-occasional slug of TCE migrating to the well
field via a surface water route.
5.
Potentially responsible parties were concerned that the
"unduly concentrates on Zone 1 as the primary source of
although other sources may exist.
RI Repor t,
contamination"
EPA Response: The conclusions presented in the remedial investigation
are the result of evaluation of EPA collected data, review of historic
data, and review of additional concurrent (potentially responsible
party, state of Connecticut, and Norwalk First Taxing District)
investigations.
The data indicate:
o The aquifer (groundwater) north, west, and south of the site has
little, if any, TCE in it.
o The surface water adjacent to the site has no TCE in it.
concentrations have been found.)
{No long term
o The aquifer east of the site (which supplies the well field)
consistently has TCE and other contaminants in it. Within the study
area, maximum concentrations of TCE, (a minimum of one magnitude of
order greater) were consistently detected in the vicinity of Main
~treet (Zone 1). Zone 1 is upgradient of Zones 2, 3, and 4 (well
field). Groundwater quality in Zones 2, 3, and 4 is impacted by
upgradient groundwater contamination For these reasons Zone 1 is
identified as the "primary" source area. Source areas in Zones 2 and 3
may exist, their impact is significantly less (i.e., one to two
magnitudes of order less) and these additional sources are therefore,
identified as "secondary" Source areas (see Section 6.4 of the RI for a
detailed discussion).
6.
Potentially responsible parties indicated that significantly more
subsurface testing is needed to identify the source or all sources of
contamination.
~PA Response: Additional testing may be required to identify all sources
(regardless of contribution amounts). Additional data is required to
design and ~mplement appropriate source clean up options. EPA believes
~~e zone of ~ajar TCE contamination has been ide?tified.
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l)
G
7.
Potentially responsible parties (PRPs) were concerned with the ability of
any individual (e.g., PRP) to investigate additional PRP's due to the
nature of the site. The contamination is moving in groundwater beneath
private property and PRP's do not have authority to conduct
investigations on such property.
EPA Response: The purpose of ~ny additional investigations will not be
for one PRP to investigate another, but to determine the need for and
proposed extent o~ remedial action in relation to the second Operable
Unit for the site.
8.
Potentially responsible parties (PRP's) were concerned that the surface
water characteristics were not assessed in greater detail. Additionally,
the surface water dilution of the groundwater would reduce risks and the
PRP's were concerned that this risk reduction was not evaluated.
EPA Response: Th~ risk assessment presented in the RI (See page 7-21)
was calculated from maximum observed concentrations at the well head.
The ~roundwater at the well head has already been diluted by Norwalk
River recharge to the aquifer. 'I'l:e :..'~s;;. d:\a2.ysis considel~ed a wo~st
, d "', ' , - ' , Oed . )y "!1e r 7L'mI"'. 'lJ"""'r""':leS 1 0 C 9-
caS8 scena 1:':'...0 \::; e:..' \'.'I,_C:-; ::1':e pliO :.':'C sel.V,- . '- '.!:.1.JJ _"''-VlL 0
deocr:dcr::': Ci~ ',Je::'''' r:..c':'cl',:atE";:"-. :::t !-:us bee~, dete~:-mi,1ed thcit s\..:c:\ scer.a::io
co~'lL-'J ,,"i ~-r. ,"'dc' ;-",,,,,,,' ,- rea' ~ s':ic cDndi.t':'oESi tllcr'efore; it ""as
....t ...t t.:~ ~ - ..:;)\.. .. . "...... ~ - _.....&. - .. - --
aF-rr':'~ci.at:e tv co:',s~.de:..- 1')0% dc;?€:;c;:1er:cp as '.:.~e basis fo~, che ::-is}~ anal}'si~.
9.
A responsible party expressed a need for the soil, analysis data and soil
sample collection points, which were known to a Field I~vestigation Team,
but not included in the RI.
EPA Response: The remedial investigation (RI) study included detailed
data regarding efforts (analysis type, procedures, locations, results,
et~.) for samplps collected during the remedial investigation. The RI
also summarized data presented in other historic or ongoing studies.
Data from these studies was summarized in Appendix A of the RI. Efforts
were made to include all relevant information. The Field Investigative
Team soil analysis data was qualitative in nature and therefore not
discussed in detail; however, this information is provided in the report
titled "Matheis Court Property Site Final Preliminary Assessment/Site
Inspecti.on Report, Norwalk, Connecticut, August 23, 1985," and can be
ootained from the U.S. EPA.
Concerns Regarding the Peasibility Study
L.
The S~at~ of Connecticut Department of Health Services (DHS) agreed that
conve~tiuna1 t,eatment, activated carbon treat~ent modules, purchase :rom
."ldjoini.ng pubi.c "ater supply (due to 100:;5 of use uf 3.5 ~GD safe yiel.n.
-------
<:
already exposed to water with low level contaminants would then be
exposed), and production well management should be screened out.
The DHS indicated that the no action option was unsatisfactory as the 5
microgram/liter proposed maximum contaiminant level (MCL) for
trichloroethylene would be exceeded. The expansion of the existing
surface water treatment system was not feasible due to a' lack of safe
y'ield. The only options that should be considered are: packed tower
aeration, GAC filtration, and aeration with GAC filtration. The DHS also
noted that the aerator on the Layne 2 production well is inadequate and
the design of the newly installed air stripper had not yet been approved
by the DHS. Also, the DHS was concerned that removal efficiencies
presented in the FS for activated carbon treatment seemed low and
recommended treatability studies be conducted for better evaluation.
Finally, DHS states that the study incorrectly indicates that the Deering
wells are relatively free of cont'amination.
EPA Response: The recommended alternative (air stripping) is one of the
options that DHS suggests for consideration. This alternative will
require compliance with the 5 ppb limit for TCE and air stripping
treatment of all well fiald water used for public supply. : The removal
efficiencies presented on page 4-23 of the feasibility study (95% for
monocyclic aromatics and 80% for halogenated aliphatic hydrocarbons
while conservative, are standard design removal efficiencies for the
specific contaminants of concern (Conway, R.A., and R.D. Ross.
Handbook of Industrial Waste Disposal Van Nostrand Rheinhold, NY, NY,
1980 (Page 179-180). Treatability studies are necessary for actual
activated carbon treatment design. However, as discussed above, the
removal efficiencies presented in the FS are adequate for evaluation
purposes. Contaminant concentrations detected in the Deering wells were
low relative to those detected in the Layne wells. For example, the
March 1985 samples showed no contaminants detected in Deering 1 and 4 ppm
TCE. 86 ppm TCE were detected in Layne 1 and 64 ppm TCE in Layne 2.
However, the possibility of contaminant increase is documented in the RI
and FS reports.
')
'" .
One potentially responsible party recommended that Alternative 2
(completion of the installation of the air stripper already in place) be
selected as it reduced risk at a modest cost relative to the other action
alternatives.
EPA Response: The selected alternative is
afte~ analysis and comparison proved to be
most environmentally sound alternative for
Kellogg-Deering Well Field Site.
indeed Alternative 2, which
the most cost-effective and
Operable Unit #1 of the
~ .
~~v~ral po~~ntially responsible parties expressed :oncern that the
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w
G
EPA Response: Purchasing water from adjoining municipalities was
considered in the FS as a remedial technology and was rejected from
further consideration due to its unreliability and failure to contribute
to a permanent solution to the contamination problem at the site.
Purchasing water from adjoining municipalities would not serve to treat
and/or destroy the existing contamination. In addition the Connecticut
Department of Hea(th Service~ has stated its concerns for the loss of the
, available safe yie~d from the well field if the purchase option were
implemented.
-.
4.
One potentially responsible party was concerned that the ~tudy did not
adequately define the existing and anticipated water demand in the
Norwalk First Taxing District. Additionally the concern was expressed
that a proper assessment (based on demand) was not presented so that a
determination of which well or combination of wells which were actually
needed could be made.
EPA Response: The projected demand for water within the NFTD was based
on water usage from both the reservoir and well field up to and including
1985 actual rates. Existing demand was defined based on most recent
available data (e.g. see page 1-10 of the Feasib1ity Study). In the NFTD
fiscal year 1984, the filter plant contributed 1,900,887,000 gallons and
the well field contributed 269,646,000 gallons (also see Table 3-1,
Kellogg-Deering Well Field Water Production Analysis (1980-1985».
The well field supply was determined to be necessary to supplement the
reservoir supply. As all wells contain contamination to one degree or
another, the remedial option selected would be required by any or all
,wells. Layne 1 is the preferred well because it has the greatest
production capacity. Wells can be used individually or m1nifolded prior
to treatwent thereby keeping the flexibility of multi-well usage at
minimal cost. As discussed above, the Connecticut Department of Health
Services (DHS) was concerned about the potential loss of the 3.5 MGD safe
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i~
5.
One potentially responsible party expressed concern that Alternatives 3,
4, and 5 (air stripping and carbon absorption, surface water treatment
expansion, and activated carbon) were not eliminated during the cost
screening evaluation as these alternatives were greater in cost yet did
not provide greater public health or environmental protection than
Alternative 2.
EPA Response: C6s't screening refers to the initial screening of alter-
, natives as per Sec~ion 300.68 (g) of the National Contingency Plan (NCP).
The FS guidance provides an order of magnitude analysis for the initial
cost screening. All alternatives presented in the FS for detailed
analysis passed the order-of-magnitude cost screening. Alternatives
which exceeded others by one order of magnitude either exceeded available
public health standards, or offered better engineering reliability, or
provided further protection of the environment, or exhibited a
combination of any of these factors. Therefore they passed the initial
cost screenng evaluation.
6.
Potentially
during peak
considered.
responsible parties felt that the "at the tap"
demand and the "No Action" Alternative was not
Sped fica lly:
health risks
adequately
a), The characterization of the public health risk had not :been adequately
addressed with respect to the dilution of well field water with
surface water from the reservoir and contamination in surface water
from the reservoir, or as a result of water treatment.
b) A detailed analysis of current and expected water demand within the
NFTD was not conducted.
c) The FS does not take into account the newly constructed air stripper.
EPA Response:
a) Dilution was considered, however, it was recognized that a small
portion of the population served by the NFTD may receive on occasion, as
much as 100% of ~heir potable supply directly from the well ,field. The
dilution considered was from mixing of groundwater from the contaminated
well and (after aeration) with the less contaminated wells (@ 1:1
dtlution). The intent of the public health assessment is to characterize
th~ risks to persons exposed to the greatest concentrations, not to
characterize the risk incurred by each and every individual. Hence, the
actual mechanics of the distribution system are irrelevant in this
regard.
The presence of conta~inatt0n i~ surface waters has not been document~G.
~:o data have ~2e~ getl-=rated that indicate that chlorination or other
wdto:!r cre3t::nen.t: processes -::onducted by NFTD result in risk to the pljbl~:.
(~.the~! such ~~eat:rnents are designed to mitigate eXpos~re to water-b0rn~
-------
s.
u
~,
:-: ,,':.: '1 _: ..; ~ : :. :. - :: =- ~ 2 ~ ~ -= :-;: ~...:. ~ =i C e:i : a r '.: i.:: J '5 ~~: ~..: :-:.. ~ ~ :..:::: ~: J -:i :. ~ ~ ~. t i. :: i ed, i. r:
'';,i'Jtd ,",': ,~st:a.Jl~:;;: a oa'::~5::-o1J:d asainst whic:-\ tr1e ::-~3k dtt::-ibutaJle to
well ~ield ~onta~ii1ation could be weighed. The carcinogenic ::-isk model
adopted by EPA treats carcinogenic effects additively. Thus, the
presence of contamination in the well field would become even more
critical if such a hypothetical scenario existed.
b)
This portion of COtmTlent No.6 is discussed in detail under Comment
No.4. In summary, the FS did use existing water supply use data.
c)
The newly installed NFTD stripper is discussed in detail and
comprises the bulk of the technical recommendations for Alternative
No.2. No.1, the "No Action" Alternative, does not consider the
benefits of the NFTD stripper as the stripper, although constructed
and in place, was not operational at the time of preparation of the
FS. The "No Action" alternative must represent the present site
situation, because the newly installed stripper is not operational,
its treatment~~capabilities could not be evaluated under the "no
action" alternative. As previously stated, the NFTD stripper
capabilities are considered under Alternative No.2.
7.
A private citizen was concerned with possible technical oversight in the
FS regarding the air stripper alternative recommendations. Specific
concerns were:
a)
The implication that "trihalane methane compounds can be removed by
the air stripping method"
~)
7he need for pure air to enter the air stripper to protect the public
from airborne particulates and organic materials, etc.
d
The need for removal of airborne pollutants of polychloro, monochloro
and ,")ther ,)Lganic '.:ompounds from air stripper emissions
,\ )
Tf-Je need to pr~vent the "unnamed" small stream on the well field
JOlIOJ:lr:: from rec!1'irging the aquifer and contaminati.ng the aquifer
",!~'::1 :,\)1>,~111'Jro and other '1rganic contaminants.
;:.- 2 ..\. ~.,.:: a, ' :~ "..~ :
:";".:' :".;"'.'-";}:-:~ ,)\,~....: ~h~ .~ff..-.)cti.'.:ent~s.s \)f :,Lt"' stripping of
c:<'"I~,,~,~t:ha".c" ':',lr:l":ldRr~:: .::hl,)rof0rm) i, wilrranted,
~:'.:t ;"f': "ntir.".>/ 'L1pli.-::'1:,1~. ~'\..le nnll trihalcrnet:tane det..:cr.~'!
1-. :':~0 '~'F:ll ::'t:: : -"W...~~; '-"I~:)~'~f"}t'7!1, ,;hich has ~~etecte(i in tr:3CI-~
:"")1~:ijt.:;~ ":.;~-:"r' ~"r.;", 't-" is nc]~. )f. ::--nncern. ~~~ 3ir- .:;tri;;~)er'3
'-"~'-:,!-.',:,l ~ .--::- t t'._~ '.":".'"
. ',; t- ~:~
'..;h::rni(;,1 L s
~j~r.;~~t~,~ :=::-. ':1"'>::
" t" ~ ~:~ r"
". l
~ ~.:
JG l;.~~: t L -,::':'''':;
~. ~_:.:1tPi:n.: t-.::J
:. 1 t. r4. ~ ..~ t
.' .
'.
. ':: ti,,:.
. ;
. 1 :: -
. . . J .- ~ .." ~. ... -:: ..."~"
_.. . . - .
. .."'"
. .
-------
()
not detected in samples from the production wells themselves. (The
analytical results for samples submitted to the EPA contract labs are
subjected to extremely rigorous quality assurance/quality control.)
The data for the contaminant plume to the east of the well field do
not indicate that chloroform contamination is extensive or highly
concentrated~ ' In our be~t'judgment, it is believed that the packed
coLumn at the wellfield will be adequate to remove chloroform from
the well field"water. The operation and removal efficiency of the
stripper will be monitored as a matter of course to assure that it
performs satisfactorily.
b)
The air stripping technology under consideration is, neither
developmental or innovative. It is presently being used with great
success at a number of locations nationwide. To our knowledge,
purified air iS'not supplied at any of these sites. No adverse
impacts such 'as you have described have been documented.
In particular, the water from the stripper will be treated by the
NFTD prior to distribution; any bacteria will be eliminated during
water treatment. Entrained particulates will also be 'removed via
filtration. Concentrations of chemical in the ambient air will be so
low that a concentration gradient (driving force for ~ass transfer)
will be virtually non-existent.
c)
An assessment of the emission of volatile organic pollutants from the
air stripper ,was conducted. These emissions are expected to disperse
rapidly. In reality, the volatile pollutants are quite amenable to
photolytic degradation once they reach the atmosphere. The
theoretical emission rates do not exceed guidelines established by
the State (Connecticut) even under presumed worst case conditions.
d)
Historic data indicates that few constituents were detected in the
unnamed stream adjacent to the well field. Furthermore, the stream
recharge to the aquifer is negligable compared to the recharge from
the Norwalk River and the yield from the aquifer east of the river.
8.
A pr~vate citizen was concerned with the completeness of the'evaluation
conducted regarding effectiveness and cost of activated carbon filters in
removing chloroorganic and other solvent type contaminants
~Response :
Ac ~ ~V.:i c~d '.:arbon
l.irt 1. ~ s
~~~ p,~sently ~n us~ for treat~ent
or TCE-
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)\.
(j
(.
contaminated groundwater at numerous locations across the nation. The
performance of these units has been monitored and the results have
demonstrated their effectiveness in removing TCE and other chlorinated
hydrocarbons. A great deal of literature is available regarding carbon
adsorption partial coefficients, carbon consumption rates, and
regeneration of spent units. 'Operation of adsorption units in series
(lead/lag) assures t~at contaminant breakthrough will not occur (even if
suspended solids foul the first unit). Filtration can easily remove any
suspended solids prior to entry to the carbon units. Little variance in
pH is anticipated through the system so that precipitation of dissolved
solids is not expected. pH control can assure that this does not Occur.
Once again, these are aspects that must be considered during the design
phase.
When the adsorptive capacity of the lead unit expires, the 2nd unit will
effect removal wbile regefteration or replacement of carbon in the front
unit takes place. The removal adsorption capacity of the revitalized
carbon can be determined during this maintenance period. If the spent
carbon cannot be regenerated, it can be replaced. Annual costs for
operation and maintenance of those units (including an itemized cost for
~arbon consumption) are included in Appendix D of the Fea~ibility Study.
9.
It was noted by a private citizen that there was a need for a schematic
representation of the air stripper.
SPA Response: The figure in Appendix C of the Feasibility Study
is a schematic representation of the Air Stripper. It is not an
built" drawing.
report
"as
lO.
A private citizen expresssed a need for a more detailed description of
the specific sampling methods used and the reliability of these methods.
SPA Response: EPA agrees that data quality must be ensured and has
developed procedures for collection, preservation, and transportation of
samples; the calibration and maintenance of field and labor tory
instruments; and the processing, verification and reporting of data. The
Kellogg-Deering data was reviewed and validated by Region I EPA to ensure
that proper sampling procedures were used by the contractor and proper
analytical techniques were used by the labortory conducting the analysis.
The laboratories used are approved under the EPA Contract Laboratory
Program (CLP). Sampl~s not meeting the requirements of this program are
reject~d. Only 3pprcved, val~dated data are used in the decision mak~ng
? r-',JC ~ q ~ .
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i~
Specific analytical methods are not generally included in th RI
reports. Methods used are described in detail in the following
publications available from U.S. EPA.
or FS
two
For Or~anic Contaminants:
U.S. EPA Contract. Laboratory Program - Statement of Work for Organic
Analysis (Multi-media, Multi-concentration), May 1985.
For Inor~anic Contaminants:
U.S. EPA Contract Laboratory Program - Statement of Work for Inorganic
Analysis (Multi-media, Multi-concentration), July 1984~
11.
One responsible
comments on the
issuance of the
party expressed concern
FS .in view of the short
.ij.J and FS.
regarding the time allotted for
period of time between the
EPA Response:
and consistent
(40 CFR 300 et
The time
with all
seq. ) .
alloted for comments on the FS was appropriate
requirements per the National Contingency Plan
12.
Responsible parties did not agree with creating two operable units as
source cleanup would possibly have reduced contamination"at the wellhead.
By splitting the. site into two operable units, a comprehensive (for both
operable units) overall solution was not selected.
'\
EPA Response: During the remedial investigation, aquifer contamination
was verified east of the site and potential source area(~) identified
beyond the site boundary. In order to reduce risk to the public in an
expeditious manner, EPA proceeded with the RIfFS for the site under the
original RIfFS objectives, but concurrently identified a second operable
unit encompassing the source area. .
There is a current need for well field water; therefore. treatment is
needed as soon as possible. In addition, there is not enough info~tion
at this time to determine the need for and extent of remedial action
relating to the site~ second Operable Unit. Therefore, speculation on
the impact of Operable Unit #2 on the remedy selected for Operable Unit
#1. is premature and fails to address the currrent need for safe potable
water. (contin'.:ed or. pCTe U (a) attac:-:l.'C1).
[3.
A potentially responsible party was concerned that EPA failed t~6consider
the acceptability of an incremental cancer risk greater than 10 in view
of. the fact that EPA accepts greater risks in certain circumstances.
EPA Response: It is EPA policy to try to reach the 10-6 level wherever
possible. It h~g b~en shown ~hat A1ternati~e No.2 (air stripp~ng) which
reaches this 10 r1sk level 1S cost effect1ve and the most envtro~4
~entally sound alternative when compared to others ranging from 10 to
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o
The Agency.recognizes the primary source of the
contamination to be in the vicinity of Main Avenue
where the so~ls are shallow and bedrock outcrops
are numerous. We also recognize that additional
studies may conclude that source control is the
appropriate remedial action for aquifer clean up.
By choosing aeration in the first operable unit,
the Agency does not believe that this is the " cost
effective remedy for aquifer cleansing. However,
we do feel because of the location of the primary
sources of .tontamination and the uncertainty of
fluid flow in fractured rock, that well head
treatment by aeration is a necessity to ensure the
protection of ~ublic health and the environment.
~
-'
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!--:'
-7
10 (see Keliogg-Deering, ROD document).
REMAINING PUBLIC CONCERNS
1.
An interested citizen was concerned about what is being done to stop
companies from polluting the groundwater?
EPA Response:
It is EPA's policy to attempt to identify parties responsible for
contamination at all National Priorities List (NFL) sites. To date,
nine PRP's have been notified of their potential liability in relation to
groundwater contamination at the Kellogg-Deering Well Field Site.
Efforts to identify other PRP's continue as part of the enforcement
activity at the Kellogg-Deering Well Field site. Through \igorous
enforcement and c~ordination with state agencies these PRP's can be
stopped from polluting the groundwater and required to clean up the
contamination for which they are responsible.
2.
An interested citizen questioned why it takes EPA such a long period of
time to conduct these studies?
EPA Response:
The EPA became involved with this site through its Superfund program
which began in 1980. In 1983 the Kellogg-Deering Well field was included
on the NFL which made it eligible for Superfund money. In 1984 water
contamination data at the wellhead was collected by the EPA and evaluated
by the Centers for Disease Control (CDC) to determine the need for
response action. The CDC determined that such actions were required:
hence EPA proceeded to conduct a detailed investigation which lasted from
1984 to 1986. This investigation helped to identify sources of
contamination and facilitated proposal of remedial actions to assure the
provision of safe potable water to the public. The detailed nature of
the investigation required two years for its completion.
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b. L
ATTACHMENT A
COKMURITY RELATIONS ACTIVITIES CONDUCTED AT KELLOGG-DEERING SITE
Community relations activities conducted at the Kellogg-Deering Site to
date include the folLowing:
o
EPA and State offic~als held a public meeting to discuss conditions
at -the site (November 1983).
o
Information repositories were established at the Norwalk Public
Library and the Norwalk Town Hall.
o
EPA held a publi~_.meeting to discuss plans for the Remedial Action
Master Plan (RAMP) for the site (July 1984).
o
EPA conducted on-site discussions
interested residents (March 1986)
plan (Jur~ 1986).
with local officials and
and prepared a community relations
o
EPA issued progress and plans fact sheets during the RI/FS process
(October 1985, April 1986).'~
o
Remedial Investigation was released for public reVlew and comment
(April 1986).
o
EPA held an informational public meeting to explain progress and
plans at the site (May 1986).
o
EPA held a public meeting at the Norwalk Public Library to describe
the workplan for the RI and to respond to citizen's questions (May
22, 1986).
o
Feasibility Study was released for public reVlew and comment
1986).
(June,
o
EPA held a public meeting at the Norwalk Public Library to discuss
the results of the FS and to respond to citizen's questions (July 17,
1986). Approximately 30 local citizens, officials and media attended
the meeting. A fact sheet describing the cleanup options was
distributed.
.J
EPA held a public hearing at the ~orwalk Public Library to record
co:urnents from the public on the draft FS (July 31, 1986). A
rranscrlpt 0r this ~earing is available at the Norwalk Public
:"ibrny.
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