United States
           Environmental Protection
           Agency
             Office of
             Emergency and
             Remedial Response
EPA/ROD/R07-84/003
September 1984
SEPA
Superfund
Record of Decision:
           Aidex SiteJA

-------
           TECHNICAL REPORT DATA         
          (PlelUe read Instructions on the revene before completing)        
1. REPORT NO.       12.        3. RECIPIENT'S ACCESSION NO.  
     - -..                  
EPA/ROD/R07- 84/003                   
4. TITLE AND SUBTITLE              5. REPORT DATE     
SUPERFUND RECORD OF DECISION:        06/19/84     
Aidex                 6. PERFORMING ORGANIZATION CODE
Council Bluffs, IA                     
7. AUTHOR(S)               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 Report   
401 M Street, S.W.      --       14. SPONSORING AGENCY CODE  
Washington, D.C.  20460                 
  "           800/00     
15. SUPPLEMENTARY NOTES                     
16. ABSTRACT                       
 The Aidex Corporation operated a pesticide formulation facility near Council 
Bluffs, Iowa between  1974 and 1981. More than 4,000 barrels of pesticides and  
pesticide wastes were stored or buried on the property. The soil, shallow zone of
ground water and surface water are contaminated with pesticides and related wastes.
 The cost-effective remedial alternative selected for this site includes: exca-
vation and off-site disposal of buried wastes and contaminated soil in excess of 10ppm
total pesticides; backfilling with clean soil and grading and seeding of the site;
expansion of the monitoring well network and biannual ground water testing; vacuuming
and washing interior  surfaces, floors and walls of the buildings onsite. The total
present worth cost of the selected alternative is $3,580,175 which includes the 
$875,000 O&M costs for thirty years of ground water monitoring.     
 Key Words: ACLs, Ground Water Contamination, Ground Water Monitoring, Contamina-
     ted Soil, Excavation, Pesticides, Background Levels, Capping, RCRA
     Closure Requirements, Off-site Disposal, On-Site Disposal   
                         , 
17.           KEY WORDS AND DOCUMENT ANALYSIS         
a.    DESCRIPTORS     b.IDENTIFIERS/OPEN ENDED TERMS C. COSA T I Field/Group
Record of Decision                     
Aidex, Council Bluffs, IA                 
Contaminated media: gw, soil                
Key ~ontaminants: pesticides, VOCs               
18. DISTRIBUTION STATEMENT       19. SECURITY CLASS (Tllis Report) 21. NO. OF PAGES
       None     76   
              20. SECURITY CLASS (Tlris page) 22. PRICE  
               None         
EPA Form 2220-1 (Rn. 4-77)
PREVIOUS EOITION IS OBSOL.ETE

-------
                                                           INSTRUCTIONS

    1.   REPORT NUMBER
        Insert the LPA report number a it appears on the cover of the publication.

    2.   LEAVE BLANK

    3.   RECIPIENTS ACCESSION NUMBER
        Reserved for use by each report recipient.

    4.   TITLE AND SUBTITLE
        Title should indicate clearly and briefly the subject coverage of the report, and rx- displayed prominently.  Set \uhlitle. if usM. in Miulicr
        type or otherwise subordinate it to mam title  When a report is prepared in more than one volume, repeal the primary title, add volume
        number and include subtitle for the specific title.

    5.   REPORT DATE
        Each report shall carry a date indicating at least month and year  Indicate  the IMSIS on uhich il was elected (,• n  Jot, <>j mi/c. Jau <>/
        approval  date of preparation, etc.).

    6.   PERFORMING ORGANIZATION CODE
        Leave blank

    7.   AUTHORIS)
        Give name(s) in conventional  order (Jo/in R. Doc. J Robert Doc. etc.).  List author's alfilialiun il 11  ilitlers truin the performing , !t.aiii-
        zation.

    8.   PERFORMING ORGANIZATION REPORT NUMBER
        Insert if performing organization wishes to assign this number.

    9.   PERFORMING ORGANIZATION NAME AND ADDRESS
        Give name, street, city, state, and ZIP code  List no more than two levels ol an orpaiii/jiionjl hireanhy.

    10.  PROGRAM ELEMENT NUMBER
        Use the program element number under which the report was prepared.  Subordinate numbers m.i)  l>c nuUuleil  in parentheses.

    11.  CONTRACT/GRANT NUMBER
        Insert contract or grant  number under which report was prepared.

    12.  SPONSORING AGENCY NAME AND ADDRESS
        Include ZIP code.

    13.  TYPE OF REPORT AND PERIOD COVERED
        Indicate interim final, etc., and if applicable, dates covered.

    14.  SPONSORING AGkNCY CODE
        Insert appropriate code.

    15.  SUPPLEMENTARY NOTES
        Enter information not included elsewhere but useful, such as:  Prepared  ID  cooperation with. I r.mslaimii nl. I'rcsi ntcd ji i unit u-iu t ni
        To be published in, Supersedes, Supplements, etc
   16.  ABSTRACT
        Include a brief ^200 words or less/ factual summary ol the most significant information contained m  lie upon  h  UK upon i ..... .nn
        significant bibliography or literature survey, mention  it here.

   17.  KEY WORDS AND DOCUMENT ANALYSIS
        (a) DESCRIPTORS - Select from the Thesaurus of tnginccrir.g and Scicntilic Icrms the proper aulhun/ed terms Hut identity the m.ii
        concept  of the research and are sufficiently specific and precise to be used as index entries lor
        (b) IDENTIIIERS AND OPEN-ENDED TERMS - Use identifiers for project names, code names, equipment designators, etc   I sc .jpen-
        ended terms written in descriptor form for those subjects for which no descriptor exists.

        (c) COSATI I II LD GROUP - I icld and group assignments are to be taken from the I 965 COSA1I Suhiett ( atepory I ist  Since Hie ma-
        jority of documents are multidisciplmary in nature, the  Primary I leld /Group assignments ) will be siveilu discipline . ^rej nl hum in
        endeavor, or type of physical object.  The application! s) will be cross-referenced with seionelaty I icKI/< .roup jssi^mne'iis ih.ii w il  inlln
        the primary postmg(s)

   18.  DISTRIBUTION STATEMENT
        Denote relea&abiliu to the public or limitation for reasons other than security lor example "Release I  nlnmieil." ( IK .nu jv.nl, ilnln\ in
        the public, with address and price

   19.8.20.  SECURITY CLASSIFICATION
        DO NOT submit classified reports to the National  Technical Information service.

   21.  NUMBER OF PAGES
        Insert the total  number of pages, including this one and  unnumbered pages, hut exclude distribution Itsi. il any

   22.  PRICE
        Insert the price  set by  the National  Technical Information Service or the Government Printing Otfice,  il known
EPA. Form 2220-1 (Rev. 4-77) (R«ver,.)

-------
                          ROD ISSUES ABSTRACT

Site;  Aidex, Council Bluffs, Iowa

Region;  VII
AA, OSWER
Briefing;
June 19, 1984
                            SITE  DESCRIPTION
    The Aidex Corporation operated a pesticide formulation facility
near Council Bluffs, Iowa between 1974 and 1981.  More than 4,000
barrels of pesticides and pesticide wastes were stored or buried on the
property.  The soil, shallow zone of ground water and surface water are
contaminated with pesticides and related wastes.

                          SELECTED  ALTERNATIVE
                i
    The cost-effective remedial alternative selected for this site
includes:  excavation and off-site disposal of buried wastes and con-
taminated soil in excess of 10 ppm total pesticides; backfilling with
clean soil and grading and seeding of the site; expansion of the
monitoring well network and biannual ground water testing; vacuuming
and washing interior surfaces, floors and walls of the buildings
onsite.  The total present worth cost of the selected alternative is
$3,580,175 which includes the $875,000 O&M costs for thirty years of
ground water monitoring.
          ISSUES AND RESOLUTIONS

    Ground water contamination has been
    detected in the shallow aquifer below
    the site.  There is no evidence of
    significant migration of contaminants
    offsite which would pose a public
    health threat.  As part of the remedial
    action, periodic ground water monitoring
    will be conducted for 30-years to de-
    tect any unexpected spread of contaminated
    ground water.  The final decision on the
    remedy for the contaminated ground water
    will be deferred until Alternate
    Concentrations Limits (ACLs) are developed
    for the site.

    The amount of contaminated soil and
    waste which will be excavated and
    transported for off-site disposal
    will be determined by a 10 ppm total
    pesticide standard.  The 10 ppm total
                                         KEY WORDS

                                            Alternate
                                            Concentration
                                            Limits (ACLs)
                                            Ground Water
                                            Contamination
                                            Ground Water
                                            Monitoring
                                            Contaminated Soil
                                            Excavation
                                            Pesticides
                                  -1-

-------
4 .
5 .
Aidex, Iowa
June 19, 1984
Continued
ISSUES AND RESOLUTIONS
pesticide standard was selected because
it: is consistent with the recommended
application rates (2-5 ppm) of the various
pesticides in normal use throughout the
State and will result in individual pesti-
clde residuals comparable to peak back-
ground levels.
3.
Capping of the contaminated soil (with-
out soil removal) in accordance with RCRA
closure requirements was rejected as a
cleanup alternative because of the high
ground water table at the site which may
periodically inundate the wastes.
The removal of pesticide - contaminated
soils to near background levels of total
pesticides along with backfilling with clean
soil eliminates the need for a RCRA cap.
Therefore, the selected remedial alterna-
ti.ve is consistent with RCRA closure
requirements.
Excavation and on-site disposal was
considered as a remedial alternative.
However, off-site disposal was selected
because it was judged to be more cost-
effective than on-site disposal, pri-
marily because of the costs of construc-
ting such a facility over a localized clay
layer with unknown load bearing capacity.
-2-
'I.
.
,
KEY WORDS
Background Levels
Capping
Background Levels
Capping
RC RA C 1 0 sur e
Requirements
. Excavdtion
. Off-Site Disposal
. On-Site Disposal

-------
SITE:
Record of Decision
Remedial Alternative Selection
Aidex Corporation, Council Bluffs, Iowa.
DOCUMENTS REVIEWED:
I am basing my decision primarily on the following documents
describing the analysis of. the cost effectiveness of remedial
alternatives for the Aidex Corporation Site:
o
Remedial Investigation and Feasibility Study Report,
Aidex Corporation, Council Bluffs, Iowa, December 1983.

State and EPA staff summaries and recommendations.
o
DESCRIPTION OF SELECTED OPTIONS:
o
Buried wastes will be excavated within the relative
perimeter of the disposal trench to a residual concen-
tration of less than 10 ppm and transported off-site
for disposal in a secure landfill.
o
Soils contaminated in excess of 10 ppm total pesticides
will be excavated and transported off-site for disposal
in a secure landfill.
o
Soils in areas of the site contaminated to levels less
than 10 ppm pesticides will be graded where necessary
to promote drainage and seeded.
o
The monitoring well network will be expanded by adding
two wells to monitor mid-range and deep water quality
downgradient from the site.
o
Buildings will be vacuumed to remove loose dust from
all accessible interior surfaces and floor and walls
will be washed.
o
O&M Requirements:
All monitoring wells will be tested biannually for
30 years or until a determination is made that
the site no longer poses a threat to nearby drink-
ing water supply wells.
Consistent with the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA), and the Na!ional

-------
,
.
;f
- 2 -
Contingency Plan (40 CFR Part 300), I have determined that remedies
described above for the Aidex Corporation Site are cost effective
and provide adequate protection of public health, welfare, and
the environment. The State of Iowa has been consulted and agrees
with the approved remedy. In addition, the action will require
future operation and maintenance activities to ensure the continued
effectiveness of the remedy. These activities will be considered
part of the approved action and are eligible for Trust Fund
mon:es for a period of one year.
EPA will defer action on the remedy for the on-site ground
water until the Agency can make a determination on Alternate
Concentration Limits (ACL's) for the site.
I have also determined that the action being taken is
appropriate when balanced against the availability of Trust Fund
monies for use at other sites. In addition, the off-site transport
and secure disposition of buried wastes and contaminated soils
is n~re cost effective than other remedial alternatives.
- C? '~IJ1j-
~ate
~
~~~
Lee M. Thomas
Assistant Administrator
Office of SOlld Waste and Emergency Response

-------
~
Summary of Remedial Alternative Selection
Aidex Corporation Site
Council Bluffs, Iowa
SITE LOCATION AND DESCRIPTION
The Aidex site, which covers approximately 20 acres, is
located in a rural area of Mills County, Iowa about 7 miles
south-southeast of Council Bluffs, Iowa, and lies near the Missouri
River floodplain. The distance to the Missouri River channel is
about three miles.. The property is bounded on the west by the
St. MaryOs drainage ditch~ the major drainage ditch in this part
of the floodplain, on the north and east by a county road, and
on the south by a cultivated field. Forty-two (42) shallow
domestic water wells have been identified within a two mile
radius of the site, and two residences are located within 1/4
mile of the site.
The Aidex site consists of four buildings totalling 66,000
square feet of space. The buildings are of all steel construction
with 7-inch concrete floors placed on fill. At least two septic
tanks were known to serve these buildings. The plant is also
connected to the nearby Burlington Northern railroad line by a
1550-foot rail siding.
The City of Glenwood, Iowa holds legal title to the property
and improvements. In April 1975, pursuant to the Act For Municipal
Support of Industrial Projects, Chapter 419 of the Iowa Code, as
amended, the City purchased the property from officers of Aidex;
authorized the issuance of industrial development revenue bonds,
in the aggregate principal amount of $760,000 for acquisition,
construction and improvement of the property; and then "leased"
the property back to Aidex. The bonds were secured by an assign-'
ment of the lease and a lien in the property to Toy National
Bank, Sioux City, Iowa, as Trustee for the bondholders, under an
Indenture of Trust and Mortgage.
Before any remedial measures were undertaken, the site
contained 3400 drums, many of which contained wastes, one buried
tank containing 8,000 gallons of contaminated sludges, one below-
grade open concrete pit containing 34,000 gallons of liquid,
miscellaneous scattered debris, extensively contaminated soils
and two burial trenches.
SITE HISTORY
As a formulator of pesticides, Aidex received bulk quantities
of concentrated pesticides which were mixed with inert materials,
solvents, oils, synergists and perfumes to create saleable products.
Liquid hazardous wastes from formulation activities at the site

-------
'\
.
i
,I
~.
,0
I

-------
- 2 -
were accumulated and stored in a reconditioned 8,000 gallon under-
ground storage tank. Solid process wastes were stored in drums,
many of which were left open to the elements and were allowed to
deteriorate and leak their contents into the environment. Process
wastes were also disposed of in two burial trenches onsite.
In November 1976, a fire destroyed the liquid formulation
building at the facility. An estimated 100,000 gallons of water
were used to extinguish the fire. Chemical contamination of the
local plant drainage ways and property was subsequently documented
by EPA investigators. Following the fire, plant production was
greatly reduced and the company filed a petition for reorganiza-
tion under Chapter 11 of the Bankruptcy Act in February 1979.
In July 1981, the proceedings were converted to Chapter 7 bank-
ruptcy, and Aidex was adjudicated bankrupt.
,
'During a July 1981 bankruptcy sale held at the site to
liquidate the assets of the Corporation, ethoprop (Mocap) dust was
spilled during an attempted removal of a baghouse dust collector
which resulted in two workmen being hospitalized with organophos-
phate poisoning. The EPA responded by coordinating cleanup
activities. It was also noted that two large metal tanks were
drained into a concrete-lined pit at the site of the former
atrazine formulation building. These two incidents are believed
to be contributing factors to the contaminated conditions at the
site.
The Aidex site was placed on the proposed National Priorities
List (NP~) in October 1981. This designation became final in
August 1983. During December 1981, immediate removal funds were
used to fence the site to control access.
In September 1982, Black and Veatch Engineers-Architects
completed a Remedial Action Master Plan which included recommend-
ations for initial remedial measures (IRM) to abate the deteriorat-
ing site conditions. The State and EPA agreed that measures to
limit public exposure and prevent wastes from migrating off-site
were needed even while further remedial investigation and feasibil-
ity studies were underway. The State of Iowa signed a Superfund
State contract on October 19, 1982, to pledge a 10 percent match
of remedial costs. The State and EPA also agreed that the IRM
would proceed in two phases. Black and Veatch was tasked to
develop a bid package for each phase. The EPA then entered into
an Interagency Agreement with the u.S. Army Corps of Engineers
to procure cleanup contractors and to provide oversight during
the implementation of the IRM. A Record of Decision for the IRM
was signed August 22, 1983.
Phase I of the IRM was completed on August 31, 1983, by
DOAppolonia Waste Management Services of Pittsburg, pennsylvania.
Work included on-site collection, bulking and temporary staging
of pesticide-contaminated solids, liquids and sludges, analysis

-------
,
.
- 3 -
of collected wastes, construction of an interceptor drainage
ditch around a portion of the site and off-site transport and
disposal of bulk liquid wastes. Liquid wastes were disposed of
by deep well injection at Empak, Inc., Deer Park, Texas.
Phase II of the IRM was completed April 5, 1984, by Rollins
Environmental Services, Inc. of Bridgeport, New Jersey. During
this phase, the materials which were packaged and stored during
Phase I were transported to Rollins facilities at Deer Park,
Texas or Logan, New Jersey for incineration or secure land
disposal.
CURRENT SITE STATUS
The Aidex site has been the subject of several in-depth,
multi-phase investigations. The results of these investigations
demonstrate that the Aidex site is widely, and in some areas,
heavily contaminated with a variety of chemicals, principally
organochlorine, organophosphate and s-triazine pesticides.
Seventeen different pesticides have been identified in soils
at this site. The consolidated results of all soil testin~ IS
shown in the figures designated 3-15, 3-16, 3-17, and 3-18
(attached). The areas of heaviest contamination show disulfoton
(4400 ppm) , atrazine (2200 ppm), aldrin (3400 ppm), prometon
(480 ppm), chlordane (670 ppm), toxaphene (380 ppm), heptachlor
(250 ppm), and ethoprop (74 ppm). These numbers represent levels
which are 500-1000 times the normal application rate for specific
pesticide compounds. Generally pesticides applied according to
the manufacturerOs instructions result in 1-3 ppm of active
ingredient on soils immediately after application.
The two burial trenches identified onsite are estimated to
contain 154,000 pounds of powdered ethoprop. Other chemicals
may also be present in the trenches.
The shallow zone of ground water and subsurface soils have
also been contaminated with pesticides. The alluvial aqui~er
beneath the site is separated into two zones by a soft clay
layer. (See hydrogeologic cross section on the following page.)
The deeper zone is used for drinking water and irrigation by
near-by residents. The soft clay layer as well as localized
artesian conditions are apparently acting to restrict, but not
prevent the migration of contaminants into the deeper zone of the
aquifer.
Analyses of fauna samples collected by the U.s. Fish and
Wildlife Service indicate that organochlorine pesticides from
Aidex have entered the food chain. The lack of vegetation over
large areas of the site indicates that residual levels of herbicides
remain highly phytotoxic five years after site operations ceased.

-------
.
w;
.@.
LEGE ..0

C_---) MEA M SOIL COMPOSITI Anllt
IICCAVATION CW TOfI JaIL LAy[1t
TOTAL Pf:STlCIOI CONCINTItATlON
GRUTU THAN 100 'P"
t"
......
.. .
.ca...
t"
.14' . ,..'
1 TO 10 "..
IlACK a veA 'CM
'''''''IIIt.. AItCttfTlCTI
Ul88A8I:r". --
a 10.-11 ~
\."I'O'II~

SURFACE SOIL CONTAMINATION LEVELS
IiIOVI..eu 1M' - JUN[ 1..3
FleUR[ 3-15
11""111

~" " "-:'1
10 TO 100 "..
','

-------
I'
~'
...
I.
.
...
"A..., . ...'
IIILUII
~",<)
10 TO 100 PPM
I TO 10 PPM
.LACK. VEATCH
1.0'...11.. .IICHITICq
-c:mr,--
NEAA-SURFAC£ SOIl.
OONTAMINATION LEVELS
DEPTH 0-1 FOOT
NOY(IIII[" "'Z- AUGUST I'"
'IGU"( '-II

-------
  , 
  I 
  r 
  I .@,
  I
  i
  I 
  I 
  I 
 I 
 I 
 , 
 .  
 I 
I  
!  
,  
I  
!  
I  
I  
I  
I  
I  
I  
I . 
I   
I   
I   
I   
(:;:) Mfa OF ':>IL COIIPOSITt .'f(lll
DC.,UIO.. Of'THI IUltlm fA". (SA"'LE 1114-101
TOTAL 'ESTICIOE COMCDf".flD"

~1 8IUfU THA" 100 "..

till it If 10 TO 100 "11

l'\\."'. \.] 'TO 10 "It
"..lIe
lcall
... ..
~-
.
...
HaLl. "1'
lLACK . VEATCH
'''01'''1'' ....8tCHITlCT8
_cm.--
NEAR-SURFN:£ lOll
CONTAMINATION LEVELS
DEPTH 1-2 FOOT
-O"IMlU 19U-AUGUST ".,
'IGUII( '-IT
.. .". .-
.,

-------
'--"
--,
,@.
.
&Ol-IU.
.&Ol-In
LEGEND

,---... AMA Of' lOll COMPOSIT( AfUIt
.._-_J rxcaV&TlOif Of' TH( IUI"(O T&U(IUIf'L( "'4-101
TOTAL f'UTlCIO( CONC(IIfTItATlON
t--1 eRunit THAN 100 "It
t"
t"
".""Ie
I' .
lULl
ec:8,. . '"'
IIIH1.
t\:'~ " "I
10 TO 100 PPII
I TO 10 PPII
lLACK . V!ATCH
11I01lllllt.. AItC,"~C"
_cnY.--
NEAR-SURFACE SOIL
CONTAMINATION LEVELS
DEPTH 2-3 fOOT
NOyrllll(1II t91Z-&UGUST ".,
'IGull( '-18

-------
'000
A
,
&0..01
110 I
tOO
&011.0'
; S'~T. (L."-..",..:..,.. - I
'-.~ ._..-_i_~~:Y_:::~_-S_:--' ~~.:~....~,~.~::~~ -~ or ~:- ;f:_~::2: :-~-5i:-:-;.--:'{,;-: ~ :
- - . ."~-:-~;--;;-i--=~-- :
_",I '."'"""Y"":.~--"""-'" ~-~- ."'~rl" ...... -.
.-.. ~ CLArY'r~*-&."--~~- --.-:-
--; - -~-~:-.j-~....' ,'-- ":'..;.~.;'.....-':- _-:-I_r-.-


.---. ---

------
-------










.~ ,-:.-:-.. .-.e..:. ..:. .. ~ :.".':.. .:8...- '.1: ,'..'.-.' '.. :.. ~: --:. ~"'~'- .0. \. '. ......
... "."-" . .......:....".........-:.:8........-.'......... ..-..,'-..-.":.-.,.
. I' .... ..1,. ~. ~'" .:'.': .,.:.~: ~: I.'"' .# .1 ..:. 4. .... ... . .' !8. :'.1.."" .e. ~. '. ",
.',_. eAt.' .1,'..'.1 ..' .................~.,.:. :"'.: . '..- 868110" .t"

~~~~i.:e. . ~ND. ., "'''e... e",e ..-..: :'.' .:::,:..\::.e.ee...:'::=:"i:

"""T ~ ,.. :r... .. '. t.-
~
&Oa "", If. II
I I .
. -. ---....._.~---~ '::':_------1
A'

I
101l.II,U,O.
I
&Da.os
,
"I.'
&011.'1,'" "
-------------
U:- :_T- ---- ---_:..T- "-- f --
-~v.:- _:-
110
.!~;~~ t~fl\~~~:~~~!.tWj~~~I~~~~~~~~~~~!:K g


"'. ....-...-..". '.-.:" ..~~.. ~; .-. ~; .,'... ,.:.: ;....: :.' .'. 8..~.,! :',. ..... -: ..: ~ '.~8.':: ::.
~ :~.- ..'..-.'- ... ,-,...-. ":.#'..'.......:.~.".'._.8:.........:.. -,'-
:..- '.',-., .,: ,., '.'.'.'.,-". ';.'.'.""'.".."::,..8...... .'.
...~..".....'. ,. .. 1."',;'--' .:.. -'."~...8,.-."'.' .-
"..'." '~.-.~-'.. ..I. '. :':, :i.:~...., "~."I.',~:..:~... ,'.' '..-:: ',',' :~.
-. ..."-.-..,,,.:... '.'..,,-,!f ,.'.'..-.-..'."""'. .-,-.' ,..' ..
'...','........". A.:'.~~ ~....'~" ;; .,.,":"~'.'. ,-,- ~"'.';._'.~. :::~-"~:'.'. :.
~':.-::~~:",":.~.':'~- .'.'..:: III .....~, '~".:;.;.~:""":.:'.'-' ,..e:.-: .:-
.. :-...-..','.... ee.., :.-- ..- . -..-.- . ..
------------
------------
--------- --------------------~

--- :!jj~'lli~
--
.
o
;:
: .,0
...
J
...
-....:
l'
L''''''-I
NO
"
.......
j.EGEND
...L
M[ASUftf:O WAUIt L(V[L
.LACK . ¥lATCH
1....([111 .AIICMnICTI
HYOIIOHOL08IC CItDII - KCTIOII 14- A'
..... enw- --
II-I I-I'

-------
- 4 -
The materials on Aidex which are of greatest concern are th~
pesticides, which are present in three general classes. The
s-triazine herbicides (atrazine and prometon) are only moderately
toxic in the pure state. Both, however, are manufactured from
cyanogen chloride and cyanuric chloride. These precursor com-
pounds are highly toxic and are likely to be present on the
site. The organophosphorus insecticides (chlorpyrifos, diazinon,
disulfoton, ethoprop, and phorate) are highly to very highly
toxic, moderately soluble in water and relatively mobile In soils.
They present both acute and chronic exposure threats to humans
and vertebrate animals. The organochlorine pesticides (DDT,
methoxychlor, aldrin, heptachlor, chlordane, dieldrin, toxaphene,
endrin and pentachlorophenol) are ubiquitous in the site soils
in widely dIfferent concentrations. The persistence of these
compounds and their tendency to bioaccumulate is well known.
Several (chlordane, heptachlor, and heptachlor epoxide) are
known carcinogens.
An assessment of the onsite risks presented by the hazards
at Aidex indicates that the greatest acute and chronic exposure
potential is associated with the material contained in the two
burial trenches. This material is accessible by inadvertent
contact and is in a form which is easily dispersed if disturbed.
The second greatest on-site risk is posed by the contaminated
ground water under the site. Although two contaminants were
found in trace concentrations in an on-site monitoring well,
the on-site water supply wells, which draw from the lower zone of
the shallow aquifer, were not contaminated when last sampled
(February, 1983). The fact that pesticides were found in soils
from the lower zone at low concentrations during site investigations
indicate that pesticides have migrated downward through tte
soil. Without effective remedial action to remove or stabilize
the majority of the sources of contamination (the burial trenches
and surface soils), the water under the site will eventually
become unfit for human consumption.
The third greatest on-site risk is the contaminated surface
soil, which is acting as a source for continued leaching into
the ground water and is a direct contact hazard to any future
occupants. Fugitive dust is of concern at the caretaker's
residence at the south end of the property.
Another but less quantifiable risk is the Aidex building
complex, which is believed to be contaminated with pesticide-laden
respirable dust on interior surfaces, and contain materials
impregnated with slowly volatilizing pesticides. In this case,
the risk is one of chronic exposures to future site occupants.
The only significant off-site risk is that off-site
ground water will become contaminated as a result of migration
from the site. This off-site ground water is not presently

-------
- 5 -
contaminated, but is hydraulically connected to the contaminated
aquifer under the site. If this water should become contaminated,
then the irrigation and drinking water supply for area residents
may be adversely affected. At present this risk is thought to
be low, due to the combination of the low velocity of water
travel and the distance to the nearest user of potable water
. (about 4,000 feet).
Enforcement History

On November 23, 1980, pursuant to Section 3008 of the Resource
Conservation and Recovery Act (RCRA), a Notice Of Violation (NOV)
was issued to Aidex Corporation for failure to comply with the
notification requirements of Section 3010(a) of RCRA. In response
to the NOV, company officials indicated that the facility had
ceased its ope~ations and was being sold.
A civil action, pursuant to Section 7003 of RCRA, for cleanup
of the site was filed on June 22, 1981. The action was stayed
by the Bankruptcy Court for over a year under the automatic stay
provisions of the Bankruptcy Act. During the pendency of the
stay, efforts were made to secure site cleanup and to recover
costs incurred through the bankruptcy court. The civil action
was subsequently voluntarily dismissed without prejudice on
March 6, 1984.
Enforcement-Current Status
Notice letters were sent to potentially responsible parties
(PRPs) on February 6, 1984. At the request of the PRPs, a con-
ference was held on March 13, 1984. Negotiations have failed to
result in an acceptable offer to perform site cleanup or for
reimbursement of costs incurred by EPA and the State. The EPA
has developed a referral to the Department of Justice for civil
litigation of this matter under Sections 104, 106, and 107 of
CERCLA.
After the remedy for the site is selected and designed, EPA
will offer the PRP's the opportunity to construct that remedy.
Alternatives
Evaluation
The feasibility study evaluated remedial options which could
be utilized for cleanup of the following areas of the Aidex
site:
1.
2.
3.
4.
Buried wastes
Contaminated soils
Contaminated groundwater
Contaminated structures
The following criteria were used in evaluating the alternatives:
1.
Effectiveness

-------
- 6 -
"
2.
3 .
4.
Technical feasibility
Cost effectiveness
Impact to the environment
The goal of the proposed remedial program is to provide
adequate protection for human health and the environment in a
cost effective manner.
Buried Wastes:
Alternatives
Estimated Costs
1-
2 .
3.
4
5.
6.
7 .
No action
Capping
Fixation
Chemical detoxification
Excavation and on-site disposal
Excavation and off-site disposal
(500-mile haul distance)
Excavation and off-site disposal
(lOOO-mile haul distance)
*
*
$287,800.
*
$240,000.
$249,100.
$374,600.
* Alternative dismissed during initial screening phase
of the Feasibility study.
** The cost of on-site disposal does not include the cost to
identify and correct problems with the foundation of the
of the disposal facility.
The feasibility study report recommends that buried wastes
be excavated and transported to an approved hazardous waste
landfill for disposal. The excavation will be of soils in and
immediately adjacent to the disposal trench and will clean up the
soil to a residual concentration of less than 10 ppm. Following
the excavation phase, the excavation area would be backfilled
with clean compacted soil and graded and seeded to provide adequate
stabilization. This alternative is technically feasible and is
proven in practice. Based on a haul distance of 500 miles,
which the Agency believes is the more likely alternative, this
is marginally less expensive (as explained below) than the on-site
disposal option, especially considering the uncertainties and
risks associated with the cost estimate for the on-site op~ion.
Under this option, the excavated wastes will be manifested
and sent to an offsite landfill is in compliance with RCRA
The selected landfill facility must have undergone a RCRA compliance
inspection within the last 12 months and have no significant
violations or other environmental conditions that affect the
satisfactory operation of the facility. These facilities must
meet the substantive requirements of Part 264 of the RCRA regulations.
If the selected landfill facility has interim status, adequate
water monitoring data should be available to assess whether the
facility poses a threat to groundwater.

-------
~
J
.
- 7 -
The no action alternative was not considered acceptable for
reasons of adverse potential health and environmental impact. '
The trenches are believed to contain as much as 154,000 pounds
. of ethoprop, a soluble pesticide which has shown high mobility
in soils similar to those found on the Aidex site. This alter-
native would not prevent migration of contaminants into ground-
water which could eventually reach drinking water wells. The
depths to the water table range from approximately 5 to 20 feet
beneath the site and it is probable that buried wastes and contam-
inated soils at depth are periodically inundated with ground
water.
Capping was not considered an acceptable alternative because
the cap would only reduce surface water infiltration into the
wastes. As stated above, the depths to the water table range
from approximately 5 to 20 feet beneath the site and it is likely
that wastes are and will continue to be periodically inundated
with ground water. Therefore, a cap will not prevent offsite
migration of contaminated groundwater.
Fixation would involve the treatment of buried trench wastes
with one or more compounds such as portland cement, clays, flyash
or charcoal which would either bind the soil and contaminants
into a solid mass or effectively absorb tHe contaminants and
restrict their migration. To date, this technology has not been
proven to be feasible or reliable particularly for a complex
mixture of pesticides which may be present in the trench. Fixation
would require the soil to be finely ground and would require
dust control during the soil preparation. The resultant material
would exhibit reduced leachability, but some leaching would be
expected to continue. The long-term mechanical integrity of the
monolithic waste formation subjected to freeze and thaw cycles
is unknown. Fixation was found not to be a technically feasible
or reliable option.
The chemical detoxification alternative would involve the
excavation of buried trench waste and the reaction of the waste
soil with chemicals which could degrade the contaminants to
non-toxic products. For pesticides the reaction is usually
alkaline hydrolysis. The EPA has examined the practicality of
using chemical detoxification methods for the disposal of small
quantities of pesticides and found that certain organophosphorus
pesticides could be detoxified readily while others produced
toxic residues. Organochlorine pesticides were not found to be
amenable to treatment. Because of the uncertain sucess of treat-
ing a mixture of pesticides, the the probability of creating
toxic byproducts and large volumes of spent chemicals and the
expected high cost, this alternative was not considered in the
final evaluation.

-------
- 8 -
The on-site disposal option was evaluated in detail. An
above-grade landfill facility would be constructed due to the
seasonally high water table at the site. This facility would
comply with the RCRA permit standards specified in 40 CFR Part
264. Such a facility must include a multilayer cap and double-
lined bottom with a leachate collection system. The Agency
reviewed several possible design options for an on-site, above
grade landfill facility and determined that the overall cost
an appropriately designed facility is likely to be more expensive
than off-site disposal. Although the engineering cost estimates
indicated that the cost of an on-site facility was slightly less
expensive than offsite disposal, these estimates did not take into
account the fact that before constructing a landfill EPA would be
required to conduct further evaluation of the ability of a subsurface
clay layer to properly support the weight of the landfill and,
depending on the results of the evaluation, to provide additional
support for the landfill. When the costs of these additional efforts
is added to the contractors cost estimates, EPA believes that otfsite
disposal will be marginally less expensive. The current cost es-
timates are so close, the additional risk of increased costs
associated with the on-site option must be considered.
Contaminated Soils:
Estimated Costs
Alternatives
4.
Excavation and on-site disposal
Excavation and off-site disposal
(SOD-mile haul distance)
Excavation and off-site disposal
(lOOO-mile haul distance)
O.
865,700.
* 139,900.
(10-100 ppm
soils only)
$2,160,000.**
$2,241,900.
l.
2.
3.
No action
Capping
Fixation
$
,-
.:> .
6.
$3,746,000
* An extrapolated cost for fixation remedy for contaminated
soils in excess of 10 ppm is approximately $275,000.
** The cost of on-site disposal does not include the cost to
identify and correct problems with the foundation of the
disposal facility.
The results of the Remedial Investigation have shown that
soils at the site are contaminated in a complex three-dimensional
matrix. There are several areas where more contaminated material
is overlain by less contaminated materials; however, the general
trend is decreasing contamination with depth. The range of
conce~trations across the site is large but some samples showed
total pesticide concentrations up to 5100 ppm. At these levels,
the pesticide compounds present an inherent hazard to various
species of plant and animal life.

-------
- 9 -
A study performed in 1970 as part of the National Soils
Monitoring Program showed that Iowa farm soils contain residues
of several organochlorine pesticides (aldrin, chlordane, DDT,
dieldrin and heptachlor). While the average concentration was
. around 0.1 ppm, peak values ranged from 1-3 ppm for individual
components. Soil samples collected in the plow zone of an ajoin-
ing farm field by the Iowa Geological Survey showed pesticides
in similar concentrations: atrazine (0.08 ppm), dieldrin (0.23
ppm), heptachlor epoxide (0.06 ppm) and Treflan (0.06 ppm).
After a detailed review of current technical literature,
Black & Veatch recommended that cleanup of contaminated soils be
performed where total pesticide content exceeds 10 ~arts per
million. Because this cleanup level approaches background levels
for pesticides when compared with peak values for, Iowa farm
soils (referenced above) no capping of the remaining soils is
necessary. Although a cap is not part of the remedy, the excavated
area will be filled with approximately three feet of clean, compacted
soil and graded. Thus, remaining residual levels of pesticides will
be beneath the clean backfill. While this recommendation is
based on engineering judgement, there are several reasons why
this level should significantly reduce the risks of harm to
human health and to the environment.
First, the cleanup of soils which exceed a total pesticide
level of 10 ppm would assure that no single chemical is present
at a level significantly higher than the normal field application
rates for pesticides. This criteria was developed recognizing
that pesticide applications to control pests have not, in general,
had an adverse impact on human health, soil microorganisms, or .
ground water quality, and there are no regulatory limits on
acceptable levels of a complex mixture of pesticides in soil.
Second, the cleanup of soils containing more than 10 ppm
pesticides substantially reduces the amount of pesticides at the
site which may cause harm or be available for transport to off-
site receptors. An estimated 8,835 pounds of pesticides are
contained in 9,900 cubic feet of soil in areas of the site where
total pesticide content exceeds 10 ppm. This represents 98
percent of the total pesticide content in all surface and near-
surface soils. By removing or otherwise managing this soil,
only two percent of the original contamination remains.
Finally, the threat of groundwater contamination is reduced
if the level of contaminants is reduced to 10 ppm at the site.
The forty feet of fine-grained clays, silty clays, and silty
sands are expected to attenuate low concentrations of pesticides
to a large extent. Also, at that level natural biological
degradation can occur. Research studies have shown that at low
pesticide concentrations (below 50 ppm) microbial activity was
generally not affected.

-------
.
,
- 10 -
The on-site disposal option was evaluated in detail b~causc
its cost was estimated to close that of off-site disposal. An
above-grade landfill facility would be constructed due to the
seasonally high water table at the site. This facility
would comply with the RCRA standards specified in 40 CRF Part
264. Such a facility must include a multilayer cap and double-
lined bottom with a leachate collection system. The Agency
reviewed several possible design options for an on-site, above
grade landfill facility and determined that there are at ~east
two significant uncertainties and risks associated with the
cost-estimates for this option.
First, the RCRA guidance document relating to the standards
for the cover design specify that the final cover have a slope
of between three and five percent unless an alternate slope will
effectively promote drainage and not subject the facility to
erOSlon. For slopes exceeding five percent, the maximum erosion
rate should not exceed 2.0 ton/acre using the USDA Universal
Soil Loss Equation. One design option employing a cover slope
much greater than the design guidance is estimated to cost $1.7
million, less than the cost of off-site disposal. This o~tion
was rejected, however, because of concerns over excessive soil
erosion. Other design options with less steep cover slopes (but
still exceeding the recommended design guidance) increase the
estimated costs of constructing the on-site option significantly.
The cost estimate for the on-site option is based on that design
and is $2.4M. This compares to $2.49M for off-site disposal of
the wastes and soils. However, the cost estimate for the onsite
option involves more risk of cost increases than that for the
offsite option because of the uncertainty described below.
The second significant uncertainty associated with the on-
site facility concerns the stability of the soils which will
provide the foundation beneath the facility. During the installatIon
of on-site monitoring wells, a layer of soft clay 20 to 40 feet
in thickness was found to be present beneath some portions of the
site under the 20 foot silty-sand and gravel alluvial layer.
Because the weight of the landfill may exceed the load bear-
ing strength of the sediments beneath it, and because the sedlment
is not homogeneous, the landfill may be subjected to uneven
settling, possibly threatening the integrity of the liner. At
this time, EPA does not have sufficient geotechnical information
to fully evaluate the potential settling problem. Thus, there
is a concern that the $2.4M estimate may underestimate the actual
cost of constructing a stable facility. Thus, the offsite dlsposal
option is considered marginally more cost effective than on-site
disposal.
The no action alternative for soils above 10 ppm was not
accepted because the risk of harm to human health and the enVIron-
ment would remain. The fact that major areas of the site remain
devoid of vegetation several years after a cessation of operations

-------
.
«
~
~
- 11 -
is symptomatic of the high residual levels in the surface soil
layer. The U.S. Fish and Wildlife analysis of animal tissues
documents the threat to fauna at the site. Without action, there
would continue to be potential for migration of these pesticides
into the ground water.
The capping alternative would involve grading the surface
as necessary to provide drainage and the installation of a PVC
liner covered by. sand and earth. By restricting water infiltration,
the driving force for downward migration of surface pesticides
is reduced. However, the high water table could inundate the
contaminated soil under the cap. This alternative is not recommended
for adoption.
The fixation option was only evaluated for soils considered
to be moderately contaminated (10-100 ppm total pesticides).
Fixation would involve mixing the soil with a fixation agent
(either activated charcoal or bentonite clay) and placing it
evenly over the bottom of an excavation. Clean soil would then
be placed over the fill. Studies by other scientists have
documented the capability of both activated charcoal and bentonite
to adsorb organic cations and thereby reduce their availability
for leaching or uptake by plants and animals. However, these
studies were performed on individual pesticides rather than on
complex mixtures like those found at the Aidex site. The EPA
received comments from the U.S. Army Corps of Engineers, from
the Centers for Disease Control and from the State of Iowa all
suggesting further consideration before selection of this alternative
even though it appears to be the lowest cost option for management
of a portion of the contaminated soils because it is an unproven
technology and the longterm reliability is undocumented. The
permanence, effectiveness, and reliability of the proposed fixation
agents has not been established. For that reason, it is not
appropriate for selecting as a remedial action.
The EPA selected the excavation and off-site disposal option
for all soils contaminated in excess of 10 ppm total pesticides
because this alternative offers a permanent and effective solution
to the problem of soil contamination, reduces the level of pesticide
contamination to near background levels, and is the most cost-
effective alternative based on a 500-mile haul distance.
Contaminated Ground Water
Alternatives
Costs
No action
$
O.
1.
2.
Periodic monitoring for 30 years
with augmented well field.
875,000.
3.
Containment and treatment
1,532,000.

-------
- 12 -
J
The no action alternative was rejected because contaminated
ground water exists on the site and the potential for migration
offslte, and eventually into drinking water supply, can not be
discounted.
The Feasibility Study recommends that the periodic monitoring
alternative be implemented. While ground water monitoring results
to date do not indicate that contaminants are reaching the zone
in the aquifer used for a drinking water supply, a longer term
threat is presented. Soil sampling data does indicate downward
migration of contaminants. Two additional wells will be needed
at a cost of $15,000 to augment the current monitoring well
network. This monitoring program will be sufficient to determine
if and when contaminated ground water begins to migrate offsite,
and thus will allow EPA to assess the need for additional protective
measures in the unlikely event that significant migration occurs.
Therefore, because the monitoring program is substantially less
expensive than the cleanup and containment alternative, monitoring
is the cost effective remedy to address the ground water concern.
The decision on whether containment and treatment of the
contminated aquifer under the site is necessary is being deferred
pendi,g further analysis.
Contaminated Structures
Alternatives
Cost
1-
:2 .
3.
No action
Vacuum interior of buildings
Vacuum and wash floors and walls
Moderate demolition
Heavy demolition
$
o.
32,800.
74,175.
523,100.
825,700.
4 .
'5.
During the final inspection of the Phase II IRM construction,
it was noted that floors in several of the buildings are stained
with residues, walls and rafters are coated with dust, and birds
roosting in the building continue to die and drop to the floor.
The roofs in several buildings leak so that rainwater makes
large puddles on the floors some of which flows into floor drains
which lead to septic tanks. Vandals have repeatedly broken into
the buildings so the threat to human health and the threat of
releases to the environment will continue if no action is taken
to cleanup contaminated structures at the site.
The vacuum alternative involves the use of high efficiency
vacuums to remove loose dust from accessible interior surfaces.
This alternative was not selected because vacuuming alone would
not remove spilled and dried residues from floors and walls.
The recommended alternative for managing contaminated structures
is to vacuum and wash floors and walls. Under this alternative
floors and walls would first be vacuumed and then be washed using

-------
~
.
~
- 13 -
~
soap and water or steam cleaning techniques. This alternative
provides more assurance that the risk of exposure to humans will
be reduced. This level of cleanup in considered minimal and
will not necessarily assure that the buildings are suitable for
occupation; however, the recommended additional cleanup of
structures is the most cost effective level of cleanup when
future use of the site is unknown.
Demolition would involve stripping interior panels and
insulation from the buildings. These alternatives are far more
costly and believed to be unnecessary given the unknown future
use of the site.
Recommended Alternatives
Section 300.68(j) of "the National Contingency Plan (NCP)
(40 CFR Part 300) July 16, 1982, states that the appropriate
extent of remedy shall be determined by the lead agencyOs selection
of the remedial alternative which the agency determines is cost-
effective (i.e., the lowest cost alternative that is technologically
feasible and reliable and which effectively mitigates and minimizes
damage to and provides adequate protection of public health,
welfare, or the environment).-
Based on an evaluation of the cost effectiveness of each
alternative as described above and on information from the State
and U.S. Army Corps of Engineers-, the EPA has determined that
offsits disposal of contaminated soils and buried waste, thorough
cleaning of buildings short of demolition and groundwater monitor-
ing are adequate to protect public health and the environment,
and are cost effective, technically feasible, and reliable. The
total cost of the recommended option is $3,455,175.
Operation and Maintainance (O&M)

Once the final remedy has been implemented at the Aidex sit~,
the only O&M activities required will be periodic monitoring of
ground water monitoring wells to assure that the remedial measures
are effective and that contaminants do not migrate into nearby
water supply wells. The projected cost of sampling and analysis
of monitoring wells biannually for 30 years is $875,000.
The State of Iowa will enter into a Cooperative Agreement
for a one year period after the remedy is completed. Through
the agreement, the State will match 10% of the O&M costs. After
this one year period, the State will complete O&M activities at
the site using State funds appropriated to the Iowa Department
of Water, Air, and Waste Management.
Community Relations

The Remedial Investigation and Feasibility Study Report was
made available to the public at six repositories between March 8,
1984 and March 29, 1984. The public was notified of the comment

-------
- 14 -
period through a news release to area media contacts and through
letters sent to persons who attended the public meeting held 1n
May 1983, prior to the initiation of initial remedial measures.
The EPA only received one comment from the public, but this
comment did not pertain to the proposed remedial action. No
comments were received from PRPs.
A public meeting is planned to brief citizens and officials
on the selected alternatives for the final remedy at the site.
Consistency with Other Environmental Requirements
The proposed action will not require on-site treatment,
storage, and disposal of hazardous wastes. The removal of
pesticide-contaminated soils to near background levels of total
pesticides will alleviate any need for capping of residual soils.
Therefore, the proposed on-site excavation is consistent with the
RCRA regulations. Off-site disposal of wastes will be in accord-
ance with the appropriate RCRA regulations for transportation
and disposal of hazardous wastes. This will include manifesting
of wastes and shipment to a RCRA approved facility.
As discussed previously, a monitoring program will be
implemented to ensure future migration is detected so that ap~ro-
priate corrective measures can be implemented.
Schedule
4Q FY 84 - AA signs ROD   
4Q FY 84 - Amend lAG for Design 
lQ FY 85 - Start Design   
2Q FY 85 - Complete Design  
3Q FY 85 - Amend SSC and lAG for Construction
3Q FY 85 - Start Construction  
lQ FY 86 - Complete Construction 

-------
~ ~
~
Responsiveness Summary
Aidex Corporation Site
This document summarizes the comments received by the Environmental
Protection Agency Region VII during the public comment period for the
Remedial Investigation and Feasibility Study Report, Aidex Corporation,
Council Bluffs, Iowa which was prepared by Black and Veatch Engineers-Architects.
The public comment period was from March 8 to March 29, 1984. During this
period, comments were received from the State of Iowa, from the U.S. Army
Corps of Engineers, from the Centers for Disease Control and one comment
was received from the public sector.
From-the State of Iowa
Comment 1: The Feasibility Study does not propose a quality control program
to assure that sQils contaminated in excess of 10 ppm pesticides have been
removed from the site. Of particular concern are soils in the area of the
burial trenches, septic tanks and tile fields and soils below the three foot
depth beneath certain "hot spots."
EPA Response: After an assessment of hazards present at the Aidex site, EPA
has determined that soils contaminated to levels greater than 10 ppm pesticides
should be excavated and removed from the site. The Feasibility Study recommends
that the dimensions of areas of removal be based on the results of previous
boring and sampling programs. While this is the most cost effective approach,
EPA agrees that a limited sampling program should be undertaken during the
design phase to determine whether significant contamination exists below
the 3-foot level and so that the volume of soil to be removed can be more
precisely calculated, and a more exact cost estimate can be developed. The
EPA also agrees that sampling should be performed after excavation to assure
that removal of contaminants to the designated level is complete.
Comment 2: The Feasibility Study states that the buildings are not useable
in their present state and recommends that a sampling program be undertaken
during the design phase. The cost of this analytical program is estimated
to be $50,000. The State recommends that the interior surfaces and insulation
be washed prior to a testing program. The testing program would then only be
used to insure that buildings have been adequately cleaned.

EPA Response: The EPA agrees that it would be more cost effective to put
dollars into the cleanup effort rather than an initial testing program.
Since the buildings are not in use, the Agency plans to vacuum and
wash the buildings to remove contaminated dust and spills and to delete the
testing program. This will reduce the cost estimate for building cleanup
provided in the Feasibility Study by approximately $74,000.
Comment 3: The Feasibility Study recommends that a treatability study for
fixation of moderately contaminated soils be performed during the design
phase. The State believes that such works should have been done during the
Feasibility Study phase so that a more accurate cost estimate could have been
prepared for the Feasibility Study Report and so that all remedial alternatives
could be evaluated together.

-------
                                    - 2 -
EPA Response:  The EPA has determined that fixation of contaminated soils
or wastes at the Aidex site would not be a reliable remedy.   Therefore,
treatability studies are not needed in the design phase.


From the Public

Comment:  EPA should collect and statistically analyze health data from  persons
who worked at the Aidex site as well  as from persons who  live nearby to  deter-
mine whether the site has caused any adverse health effects.   The EPA should
continue to monitor the health of former employees for some  time into the future,

EPA Response:  EPA is interested in environmental concerns which affect
community health and will provide this comment to the federal agency whose
mission is to evaluate health problems, the Centers for Disease Control  in
Atlanta, Georgia.


     the Corps of Engineers
Comment 1:  The Corps recommends that additional  explorations  and sampling
be accomplished during the design phase.  Locations of trenches and quantities
of wastes indicated by geophysical  methods during the remedial  investigation
should be confirmed by borings or test pits.   Also, the wastes  must be identi-
fied and this information included  in the bid package so that  an appropriate
disposal facility may be identified and priced.

EPA Response:  EPA agrees with this comment and will  request that the  Corps
incorporate these items into the workplan for the design phase.

Comment 2:  The Corps believes that it would  be prudent to undertake some
sampling and analysis of soils below the three foot level  during the design
phase to better estimate the extent of contamination  and the volume of soils
to be removed.

EPA Response:  See response to Comment 1 from the State.

Comment 3:  The Corps has reservations pertaining to  the proposed fixation
technique because there is not sufficient, up-to-date, supporting information
presented in the Feasibility Study  (FS) Report to conclude that fixation will
adequately reduce the hazard to acceptable levels.

-------
                                    - 3 -
EPA Response:  EPA has reviewed the proposal in the FS and reached the same
conclusion.  The cost of a treatability study (estimate - $50,000} will  be
applied toward the removal of moderately contaminated soils.

Comment 4:  The FS Report discounts any risk/hazard associated with the  septic
system which served the Aidex building complex.  The Corps feels that septic
system components should be located during the design phase and sludges  in
septic tanks and soils around laterals should be sampled to determine whether
removal is necessary.

EPA Response:  EPA will request that the Corps incorporate these recommendations
into the design workplan.

Comment 5:  The FS report does not provide a cleanliness criteria for buildings
at the site.  This 'should be determined during the design phase.  The Corps
does not recommend the extensive sampling program proposed in the FS Report
but rather a limited sampling program during the design phase to estimate
the amount of demolition necessary.  Then following cleanup work, the buildings
should be sampled to assure that they were adequately cleaned.

EPA Response:  EPA has given careful consideration to the level of cleanup
which should be performed in buildings at the site and has decided to vacuum
and wash down building interiors without an additional testing program.   These
measures will remove contaminated respirable dust and materials spilled  on
walls and floors.  While this remedial approach is the minimum amount of work
necessary to protect the health of future site occupants, it is the most cost
effective and environmentally sound approach when the future use of the  site
is unknown.

Comment 6:  In addition to the two groundwater monitoring wells recommended
in the FS Report, the Corps recommends that an additional two-well cluster be
installed near the bluff, south of the road along the south boundary of  the
site.
                                                                               • \

EPA Response:  Groundwater flow away from the site has been shown to be
toward the west and southwest toward the Missouri River.  The wells proposed
by the Corps are outside of the zone of contamination or potential contamination
from the site and the Agency considers them unnecessary in order to protect
human health and the environment.
From the Centers for Disease Control:
Comment 1;  The Centers for Disease Control (CDC) recommends that the
proposed fixation option for soils contaminated between 10 and 100 ppm
total pesticides be reconsidered by the Agency before selecting this option.
CDC believes any decision to select this alternative should be based first
on past studies demonstrating the long term effectiveness of the charcoal
fixation agent in similar soils, and second on preliminary onsite testing
to determine its effectivenss.

-------
                                     - 4 -
 EPA Response:  See EPA Response to the Corps'  Comment  3.

 Comment 2:   A risk assessment should be performed to determine  whether  thl
 soil  pesticide levels at the 1 to 10 ppm range could adversely  affect humavr-
 health through any potential  onsite routes  of  exposure if  these soils are
 left  in place on the site.   This assessment should be  performed for  each of
 the more highly toxic pesticides found.  Legal  application rates  of  different
 pesticides  on various land  uses and plant residual  standards  could be used
 to help assess the significance of the 1 to 10 ppm range.


 EPA Response:' The Agency believes that a risk assessment  has been performed
 to the extent possible for  soils contaminated  with pesticides in  the 1-10 ppm
 range.  Application rates,  Teachability rates  and health effects  were all
 considered  during the risk  assessment although the synergistic  effects  of the
 pesticide mixture could not be calculated.

 Comment 3:   CDC agrees with the recommended action for continued  groundwater
 monitoring.  CDC believes this monitoring is warranted based  on sampling
 information to date.
 Community Support for the Remedy

      No public meeting was held during the  public  comment  period  because  none
 was requested.  However,  during the public  meeting held  in May  1983  prior to
.the initiation of initial  remedial  measures,  community  leaders  and citizens
 voiced their support for  the Agency's  efforts to clean  up  the site.   They
 asked to be kept informed as the work  progressed.   The  EPA and  the Corps  of
 Engineers have worked together to provide information on a frequent  basis to
 the community.  A monthly progress  report has been provided to  the Mills
 County Auditor in Glenwood,  Iowa.  She also maintains an information repository
 on  the project.

      A public meeting is  planned in the near  future to  provide  details  of the
 final remedial program at the site.

-------