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fcO 0 00 0 0 7
UNITED STATES ENVIRONMENTAL PROTECTION AGENCYREGIONS
23° SOUTH DEARBORN ST.CHICAGO, ILLINOIS 60604
REPLY TO THE ATTEWON OF-
1 8 1988CERTIFIED MAILRETURN RECEITT REQUESTED
Mr. James MoranFifty-Sixth Century Antrim
Iron Company Inc .1 Gul f & Western PlazaNew York, New
York10023
Dear Mr . Moran :
The U.S. EPA received the "Preliminary Endangerment
AssessmentAntrim Iron Works Site" (a.k.a Tar Lake) for review on
October 5,1988 and is herein submitting its review comments
(enclosed).This Preliminary Endangerment Assessment (PEA) cannot be
approved,in whole or in part, because the PEA is deficient with
respectto the standards and specifications required by the Tar
LakeRI/FS Consent Order.
In summary, the PEA is deficient because it:
Does not adequately address the requirementsof U.S. EPA
Endangerment Assessment guidance
Inadequately and incompletely uses the datacollected during the
remedial investigation
Does not to provide toxicol ogi cal data forU.S. EPA Hazardous
Substance List contaminantsfound in Tar Lake groundwater.
Ambiguously and incorrectly represents theconcentrations of
contaminants observed 1nTar Lake groundwater.
The details of these deficiencies are discussed in the
enclosedU.S. EPA comments. You will note that U.S. EPA's PEA
reviewcomments also include specific instructions for modifying
thePEA.
EPA Region 5 Records Ctr.
209151
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The U.S. EPA approved schedule for s u b m i s s i o n of the r
e v i s e dPEA is forty-five (45) calendar days from the date of t
h i sletter. The U.S. EPA expects and requires that the expertisein
hazardous waste site i n v e s t i g a t i o n required by Section
I ofthe Tar Lake RI/FS Consent Order be immediately a p p l i e d
so thatthis schedule can be met.
In the event that the 56th Century Antrim Iron Company,
Inc.fails or declines to meet this schedule or submits a
deficientrevised PEA, the U.S. EPA may be required to enforce the
termsof the Tar Lake RI/FS Consent Order.
Please contact me if you have any questions.
Sincerely,
Peter M i l l e rRemedial Project Manager
End osure
cc: T. Eftaxiadis, MDNRRoger Grimes, U.S.~EP1\ ORCDavid Tripp,
Dykema, Gossett et alElisa R i v l i n , G u lf + WesternP h i l
Coop, En-Safe
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U.S. EPATar Lake Preliminary Endangerment Assessment
Review Comments
The Tar Lake Site (a.k.a. Antrim Iron Works Site) Preliminary
Endanger-ment Assessment (PEA) was reviewed by U.S. EPA pursuant to
the provisionsof Section II (E) of the Tar Lake RI/FS Consent
Order. The provisionfrom Section II (E) is:
" EPA's approval or disapproval [of reports] shall be based on
thesubmittal's conformance to the standards and specifications
inExhibit A [the RI/FS Work Plan], as it may be amended pursuant
tothis Consent Order. In the event of disapproval, EPA shall
in-clude a statement of what modifications or additions are
required."
The "standards and specifications in Exhibit A" include:
"Endangerment Assessment Guidance" issued November 22, 1985 byJ.
Winston Porter, Assistant Administrator, U.S. EPA
The PEA was also reviewed to determine the extent to which it
met theobjectives of the RI/FS. The Tar Lake RI/FS objectives (from
Exhibit A,the RI/FS Work Plan) that most directly pertain to the
PEA are:
- To delineate the areal extent of hazardous substance
contami-nation at the site;
- To determine whether groundwater contamination has occuredin
the vicinity of the site, the areal extent of such contami-nation;
and the impact, if any, on nearby private wells;
To meet RI/FS objectives, the RI/FS Work Plan states that
"TheRemedial Investigation will provide technical information
regardingthe nature of the contributing waste materials at the
site; the flowpaths and impacts of contamination on various media;
the flow pathsand impacts if no remedial action is taken; and
identify potentialrisks to the public health and welfare and the
environmental impactsof various remedial action alternatives."
Finally, the PEA was reviewed to determine the extent to which
itaccurately and completely represented site characterization
datacollected pursuant to the Tar Lake RI/FS.
The review comments were prepared by excerpting statements from
the PEA,and using these as a basis for comment. In the following
pages, thePEA excerpt or excerpts are cited, along with their
location(s) in thePEA, and this is followed by the U.S. EPA
comment.
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- Page 1, second paragraph:
" This sequence of studies was made necessary because prior
analyticalstudies had failed to establish Tar Lake's impact on
ground water otherthan to associate it with possible organoleptic
affects in privatedrinking water wells immediately west of Tar
Lake."
COMMENT: Prior analytical studies indicated the presence of
leadand phenol in Tar Lake groundwater and resulted in TarLake's
inclusion on the Superfund National PrioritiesList. The statement
would be more correct if it read"This sequence of studies was made
necessary because prioranalytical studies had failed to
qualitatively or quanti-tatively identify the odorous contaminants
in Tar Lakegroundwater." Please revise it accordingly.
- Page 1, third paragraph:
"...this assessment report has been prepared In accordance
withthe "Endangerment Assessment Guidance" memorandum prepared
onNovember 22, 1985 by J. Winston Porter..."
COMMENT: The PEA does not address the requirements of the
Endanger-ment Assessment guidance in that it does not
adequatelyidentify and characterize:
a. Hazardous substances and/or hazardous wastespresent in all
relevant environmental media(e.g. air, water, soil, sediment,
biota);
b. Environmental fate and transport mechanismswithin specified
environmental media, such asphysical, chemical and biological
degradationprocesses and hydrogeologic evaluations
andassessments;
c. Intrinsic toxicological properties or humanhealth standards
and criteria of specifiedhazardous substances or hazardous
wastes;
d. Exposure pathways and extent of expected orpotential
exposure;
e. Populations at risk;
f. Extent of expected harm and the likelihoodof such harm
occuring (i.e. risk characteri-zation).
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- Page 1, fourth paragraph:
" While full characterization of all ground water contaminants
isnot presently possible due to limitations inherent in the
scientificprocedure, a list of predicted compounds has been
prepared."
COMMENT: The first phrase of this sentence needs to be focusedon
results of Tar Lake investigations, as presentpossibilities of
other scientific procedures to charac-terize Tar Lake remain to be
examined. The firstphrase should instead read " While full
characterizationof Tar Lake groundwater contaminants was not
achievedwith the the analytical procedures used,".
The "list of predicted compounds" discussed in thesecond phrase
presumably refers to the list of "Pre-dicted Alkyl Phenols" that
appears in Table 2, page20, of the PEA. This list was based on the
resultsof the 10 samples in which the Special Proceduresanalysis
revealed an "abundance of identifiablephenols" (RTI, May 9, 1988)
Because these 10 samplesalso included other analytes of note, and
othergroundwater samples contained contaminants such asnapthalene,
benzene, ethylbenzene, and toluene,this list of "Predicted Alkyl
Phenols" is incompletefor the purposes of representing possible and
actualcontaminants found in Tar Lake groundwater.
Additionalcompounds that need to be included in the
predictedcompound list are discussed elsewhere in these
comments.
- Page 2, first paragraph:
"...the PEA concludes that the extensive expenditure of
resourcesnecessary to further evaluate these compounds is not
justified inlight of the toxicological data which does exist, the
low concen-trations, the limited receptor impact and the age of the
site."
COMMENT: Review of Tar Lake RI data and this PEA requiresU.S.
EPA conclude that expenditure of resources tofully and properly
characterize Tar Lake pursuant tothe National Contingency Plan is
still necessary.As noted in these comments, conclusions that the
PEAhas drawn are compromised by the limited list ofcompounds for
which the PEA provides toxicologicaldata; ambiguous and incorrect
constituent concentra-tions which are used to represent the site
conditions;and the PEA's neglect of both air inhalation anddirect
contact receptor impacts.
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- Page 2, Section 0, top of page:
"These compounds are present at levels below 1 ppb."
- Page 15, Section 2.0, first paragraph:
" The colorimetric tests, although considered as screening
testsonly, had shown phenolic concentrations ranging from 3 ppb
ingroundwater to 64 ppb."
- Page 22, Section 2.2, first paragraph:
" Table 1 provides a summary of the approximate concentrations
ofthe various alky! species. For purposes of the
PreliminaryEndangerment Assessment, a concentration of 0.5 ppb
[partsper billion] was used for the Health Assessments as this
isthe approximate concentration of the most common species."
- Page 29, Section 3.2, second paragraph:
" Therefore it is assumed that for purposes of the PEA, the
AntrimIron Works Site is the source of groundwater complaints in
thisarea and that the source of these complaints is alkyl phenols
atconcentrations below 1 ppb."
Page 35, Section 6.0, third paragraph:
" The highest reported values for alkyl phenols is 0.5 ppb
percompound. Typical concentrations are in the range of 0.05 to0.3
ppb."
COMMENT: This series of excerpts pertain to the PEA's
represen-tation of organic constituent concentrations in Tar
Lakegroundwater. As they appear in Sections 0, 2.2, 3.2,and 6.0 of
the PEA, these statements could be mis-interpreted by reviewers of
the PEA who are not familiarwith Tar Lake RI data. RI data indicate
that Tar Lakegroundwater contains a mixture of alkyl phenols
andother organic and inorganic constituents, with totalphenolic
concentrations in any given offsite samplemore on the order of 100
ppb than 1 ppb, as indicatedby field screening results. In the
revised PEA, therecan be no ambiguity about individual versus total
con-centrations of contaminants in Tar Lake ground
watersamples.
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- Page 2, Section 0, top of page:
"These compounds are present at levels below 1 ppb."
- Page 22, Section 2.2, first paragraph:
" Table 1 provides a summary of the approximate concentrations
ofthe various alkyl species. For purposes of the
PreliminaryEndangerment Assessment, a concentration of 0.5 ppb
[partsper billion] was used for the Health Assessments as this
isthe approximate concentration of the most common species."
- Page 29, Section 3.2, second paragraph:
" Therefore it is assumed that for purposes of the PEA, the
AntrimIron Works Site is the source of groundwater complaints in
thisarea and that the source of these complaints is alkyl phenols
atconcentrations below 1 ppb."
Page 35, Section 6.0, third paragraph:
" The highest reported values for alkyl phenols is 0.5 ppb
percompound. Typical concentrations are in the range of 0.05 to0.3
ppb."
Page 35, Section 6.0, fourth paragraph:
" Based on available data it is concluded that they [compounds]
poseno endangerment at the concentrations exhibited in Tar Lake
ground-water."
Appendix 1
" Toxicological Data and Health Assessments for Antrim Iron
WorksSite"
COMMENT: These five excerpts and review of Appendix 1 indicate
thatthe that the PEA has chosen to use the concentrations
ofindividual, rather than total, alkyl phenols to estimatehealth
risks associated with ingestion of Tar Lake ground-water, and that
the PEA makes no attempt to sum up thetotal health risk of all the
individual contaminants.Since any given sample of Tar Lake
groundwater containsmultiple alkyl phenols and other organic
contaminants, thePEA needs address health risks associated with
ingestionand exposure to the mixture of all these organic
contami-nants. The PEA also needs to evaluate health risks
associ-ated with ingestion of and exposure to the benzene,
ethyl-benzene, toluene, xylenes, napthalene and tentatively
identi'fied compounds revealed by Tar Lake RI data.
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- Page 5, second paragraph:
"Tar Lake appears to have shrunk by more than 50% since the
1930'saccording to an evaluation of aerial photographs."
COMMENT: The exact means of deriving this 50% figure needs to
beshown, as does the fate of the now apparently non-existentportion
of Tar Lake. This sort of analysis may have someuse in determining
the rate at which Tar Lake is volatili-zing into the air and
migrating into the groundwater.
- Page 5, third paragraph:
"The 56th Co. has not utilized the site."
COMMENT: The statement is meaningless. It would be mean moreif
it read " Gulf + Western owned the site until 1985,and then sold it
to the 56th Co". Please revise itaccordingly.
- Page 6, top of page
"Local residents indicate that only a few homes continue to
usegroundwater."
COMMENT: Precise information on these "few homes", includingwell
locations, number of users, water usages andother information to
properly evaluate receptorimpacts should be prominently mentioned
in the PEA.
- Page 11, paragraph 2:
" If Tar Lake does contain still bottoms, the original
constituentsshould be phenolic aldehydes, ethers, and diols."
COMMENT: This list is incomplete without inclusion of other
constitu-ents associated with wood tar (i.e. polynuclear
aromatichydrocarbons). RI data, scientific literature and data
fromtwo similar Superfund sites (Westline, PA, and Cliffs-Dow,
MI)indicate that Tar Lake contains a more extensive list of
con-stituents than that presented in this PEA. Data from
theremedial investigations at these other two sites have
beenprovided to your consultant in a separate transmittal.
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- Page 13, Section 1.3
" 1988- Ground water samples from monitoring wells and
privatewells were taken as a part of the RI/FS. Analysis con-firms
presence of alkyl phenols at levels below 1 ppbper compound."
COMMENT: The second statement is incorrect. RI data
indicatesconcentrations of alkyl phenols up to 59 ppb and
otherorganic contaminants in groundwater at concentrationswell over
1 ppb.
- Page 15, Section 2.1
" Table 2 is a summary of the results obtained."
COMMENT: Table 2 is list of predicted compounds, and not a
summaryof Special Procedures analytical results. A
comprehensivesummary of the Special Procedures analytical results
needsto appear in the revised PEA. Please be sure to includethe
results from all Special Procedures samples.
- Pages 17 and 18, Table 1
"Tar Lake Alkyl Phenols"
COMMENT: This tabulation of data is incomplete without
addi-tional explanation and qualification. The
additionalexplanation and qualification should be in the formof
footnotes to explain that the table is based on alimited number of
samples and that there were otherorganic constituents, in addition
to alkyl phenols,found in those and other samples. In addition,
pleaseuse the tentatively identified phenolic compoundsfound in the
CLP organic data for any list of "TarLake Alkyl Phenols" that
appears in the revised PEA.
- Page 19, paragraph 2
"A list of predicted compounds was then prepared using CRC
Handbookof Chemistry and Physics, 68th edition, 1987, CRC Press,
Boca Raton,FL. to obtain lists of known compounds meeting the
criteria ofC2 through C12 alkyl phenols."
COMMENT: Tar Lake RI data indicate the presence of alkyl
phenolsnot shown in Table 2. The CRC Handbook may thereforenot be
the best reference for researching predictedalkyl phenols
associated with Tar Lake.
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- Page 19, fourth paragraph:
" Volat i le analyses were negative for chemical species except
forone well which showed positive values at less than 10 ppb for
ben-zene and toluene . This same well showed an estimated
positivevalue for napthalene. This combination of compounds appears
tobe the result of gasoline contamination of the well or the
sample.Since these compounds [benzene, toluene, napthalene] do not
appearin other wells they are not further addressed in the
preliminaryendangerment assessment."
COMMENT: RI data show estimated positive values for napthalenein
three monitor wells, estimated positive valuesfor benzene in two
monitor wells, an estimated positivevalue for toluene in one
monitor well, fully quantifiedvalues for ethylbenzene in two
monitor wells, and afully quantified value for total xylenes in one
monitorwell. Given the limited number (8) of monitor wellssampled
for U.S. EPA Hazardous Substance List volatileand semivolatile
compounds , and the presence of thesecompounds in three wells
downgradient from Tar Lake,the U.S. EPA must conclude that the PEA
has incorrectlydismissed the significance of the presence of
theseconstituents in Tar Lake groundwater.
- Page 20, Table 2
"Predicted Alkyl Phenols"
COMMENT: To properly support conclusions about Tar Lake
substancesof concern for all relevant media, this table needs to
berevised to include aromatic hydrocarbons, polynuclear aro-matic
hydrocarbons and other constituents of wood tar. Ifpreferred, a
second table titled "Predicted Compound List"may be prepared. Any
list of predicted alkyl phenols thatappears in the revised PEA will
need to include the tenta-tively identified alkyl phenols found in
the CLP organicsanalyses performed during the Tar Lake RI. Any list
ofpredicted compounds that appears in the revised PEA willneed to
include other compounds tentatively identifiedin the Tar Lake RI
data (all three matches).
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- Page 21, Section 2.1, first paragraph:
" The semivolatiles analyses were generally negative except
formonitoring wells six and seven which were positive for
2,4-di-methylphenol at 57 and 59 ppb respectively. Quality
assurancereviews indicate that these reported data represent
multiplealkyl phenols rather than the single species 2,4-dimethyl
phenolhowever."
COMMENT: Review of Tar Lake RI data indicates that these
con-taminants are present at the stated concentrations,and that
other alkyl phenols are present in thesesame samples. Note that Tar
Lake RI data indicatesubstantially different retention times for
2,4-di-methyl phenol and the other tentatively identifiedalkyl
phenols found in these samples.
- Page 21, Section 2.1, second paragraph:
" Metals data, summarized in Table 6, are generally
represen-tative of the localized groundwater conditions of Antrim
County."
COMMENT: Data provided in the PEA are insufficient to
substantiatethe statement. The revised PEA should include
additionalbackground metals data for comparison with Tar Lake
RIdata.
- Page 21, Section 2.1, second paragraph:
" Although lead has been reported in association with Tar
Lake,the data do not confirm this association. Therefore lead
hasnot been addressed in the PEA."
COMMENT: The presence of lead in what was considered an
up-gradient well, and the limited amount of groundwaterand other
data available for the Tar Lake do not providean adequate basis for
dismissing lead as a constituentassociated with Tar Lake.
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Page 22, top of page:
" In summary, the Tar Lake sustances of concern are alkyl
phenols,principally C2 and C3 alkyl phenols."
COMMENT: Tar Lake RI data, scientific literature, and RIdata
from similar sites causes U.S. EPA to concludethat Tar Lake
substances of concern are not limitedto C2 and C3 alkyl phenols.
The statement shouldinstead read " In summary, the Tar Lake
substancesof concern include aromatic hydrocarbons,
polynucleararomatic hydrocarbons, alkyl phenols and other
sub-stances associated with wood tar wastes." Pleaserevise it
accordingly.
Page 22, Section 2.2, first paragraph:
" Table 1 provides a summary of the approximate concentrations
ofthe various alkyl species."
COMMENT: Concentrations of substances that appear in Tables 3and
4 must also be discussed in this section.
- Page 22, Section 2.3:
" A complete description of the analytical methodology used and
thefield and laboratory quality assurance may be found in the
QualityAssurance Project Plan for the Antrim Iron Works Site."
COMMENT: The statement should read " A complete descriptionof
the analytical methodology used and the fieldand laboratory quality
assurance criteria may befound in the Quality Assurance Project
Plan for theAntrim Iron Works Site." The extent to which
datacollected met these criteria should also be discussedin this
Section. Any RI/FS data quality problems needto be prominently
mentioned.
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- Page 23, Table 3
" Volatile Organics Analyses - Tar Lake Ground Water"
COMMENT: RI data indicate that the concentrations of ethyl
benzeneand total xylenes that appear in monitor well 6 werefully
quantifiable. Please delete the "D" data quali-fiers for these
contaminants.
- Page 27, Section 3.1, first paragraph:
" Relevant data for the alkyl phenols in environmental
settingsis generally not available from scientific literature.
Adsorp-tion coefficients, photodegradation rates, decomposition
rates,and transformations in environmental media are not available
formost of the compounds. Nevertheless considerable evidence
existsthat the still bottoms which comprise Tar Lake are
undergoingdegradation; as the volume and area of the Lake have
decreaseddramatically in size since AIWC operations on the site
ceased."
COMMENT: The revised PEA will need a full bibliographyof the
scientific literature used to supportthe PEA's conclusions.
Relevant data for all thecompounds associated with Tar Lake
(includingaromatic and polynuclear aromatic hydrocarbons)
inenvironmental settings need to be examined toaddress the
requirements or the EndangermentAssessment guidance. In addition,
the U.S. EPA isnot aware of the "considerable evidence"
regardingthe degradation of Tar Lake sludges.
- Page 27, Section 3.1, second paragraph:
" Table 7 contains a summary of data available for these
compounds."
COMMENT: Table 7 will need to address all Tar Lake substancesof
concern in the revised PEA.
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- Page 33, Section 5.1, second paragraph:
" All residents within this area have minimized their exposure
tothese compounds by obtaining alternate drinking water
supplies."
COMMENT: This statement needs more substantiation. It isU.S.
EPA's understanding that some residents inthe affected area
continue to draw water from theTar Lake contaminant plume.
- Page 35, Section 6.0, first paragraph:
" A review of analytical data obtained for the Antrim Iron
WorksSite results in a conclusion that the substances associated
withthe site are alkyl substituted phenols."
COMMENT: The U.S. EPA only partially agrees. Tar Lake RIand
other data require U.S. EPA to conclude thata more extensive list
of substances are associatedwith Tar Lake. The statement should
instead read"A review of analytical data obtained for theTar Lake
Site RI results in a conclusion the thesubstances associated with
the Tar Lake groundwaterinclude alkyl substitued phenols, aromatic
hydro-carbons, polynuc-lear aromatic-hydrocarbons, andother
contaminants associated with wood tar wastes."
- Page 35, Section 6.0, second paragraph:
" These compounds exist in groundwater on and off site."
COMMENT: This statement should include all the matrices whereTar
Lake constituents are found, including Tar Lakeitself, subsoils
under Tar Lake, and the air surroun-ding Tar Lake.
Page 35, Section 6.0, second paragraph:
" The only migration pathway is via groundwater"
COMMENT: This statement indicates that the PEA has chosento
ignore the significance of air migration ofTar Lake
contaminants.
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- Page 35, Section 6.0, second paragraph:
" The population at risk are users of the affected aquifer
westof Tar Lake."
COMMENT: In addition to ground water users, Tar Lake
presentshealth risks for direct contact and via air inhalationfor
both humans and biota.
- Page 35, Section 6.0, paragraph 4
" There are substantial data gaps in the toxicological
literaturefor these compounds."
COMMENT: A more comprehensive list of predicted compounds
associatedwith Tar Lake, one that includes aromatic
hydrocarbons,polynuclear aromatic hydrocarbons, and compounds
tenta-tively identified in Tar Lake RI data will reduce
thesignificance of "data gaps" in toxicological literatureavailable
for alkyl substituted phenols.
- Page 31, Section 4.0, paragraph 3
-"-None of the compounds has been found be- carcinogenic -or
terato-genic."
Page 35, Section 6.0, paragraph 4
" However the compounds are not suspected carcinogens or
teratogens."
COMMENT: The "compounds" to which the PEA refers in these
twostatements are limited to the "Predicted Alkyl Phenols"which the
PEA uses to characterize the site. Otherorganic compounds
associated with Tar Lake, includingthe benzene and napthalene
observed in the Tar Lakegroundwater and those which are likely to
comprisethe Tar Lake sludges, are carcinogenic.
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- Page 35, Section 6.0, paragraph 5
" The toxicity of direct contact exposure has not been assessed.
Itis concluded however based on skin irritation properties of
thecompounds that there is a risk associated with direct
contact."
COMMENT: Direct contact and air inhalation exposure routes
needto be adressed.in the revised PEA.
In summary, these comments indicate that the PEA is deficient
with respectto the criteria against which it was reviewed, and
therefore cannot beapproved by U.S. EPA in whole or in part.
Before the PEA can be approved, it must adequately characterize
Tar Lakein accordance with U.S. EPA Endangerment Assessment
Guidance requirements.So that the 56th Co. understands U.S. EPA's
requirements for the modifiedPEA, specific instructions for
addressing each of the criteria in theEndangerment Assessment
Guidance are herein provided:
a. Hazardous substances and/or hazardous wastes present in all
relevantenvironmental media (e.g. air, water, soil, sediment,
biota);
Tar Lake RI data, scientific literature and data from
similarSuperfund-sites shall be used to develop a
comprehensive-predictedcompound list of hazardous substances,
pollutants, and contami-nants likely to be found in Tar Lake
sludges. The compounds andclasses of compounds in the comprehensive
predicted compound listshall include at a minimum phenols, aromatic
hydrocarbons, andpolynuclear aromatic hydrocarbons. Be sure to
include the phenols,furans, and substituted benzenes that were
tentatively identi-fied in the Tar Lake RI groundwater samples.
Relevant media identified and characterized by the modified
PEAshall include groundwater, air, Tar Lake sludge, and the
soilsunder Tar Lake.
b. Environmental fate and transport mechanisms within specified
environmentalmedia, such as physical, chemical and biological
degradation processesand hydrogeologic evaluations and
assessments;
Using the aforementioned comprehensive predicted compound
listand relevant media, the PEA shall address environmental fate
andtransport mechanisms for the predicted compounds in each of
therelevant media. To the extent possible, rates of
contaminantmigration into the air, through the unsaturated zone,
and ingroundwater should be estimated.
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15
c. Intrinsic toxicological properties or human health standards
andcriteria of specified hazardous substances or hazardous
wastes;
The PEA shall identify and characterize the
toxicologicalproperties of all compounds and classes of compounds
in thecomprehensive predicted compound list.
d. Exposure pathways and extent of expected or potential
exposure;
The PEA shall characterize exposure to contaminated
air,contaminated groundwater, and direct contact.
e. Populations at risk;
The PEA shall precisely quantify populations affected and
po-tentially affected by Tar Lake groundwater, Tar Lake air,
anddirect contact with Tar Lake.
f. Extent of expected harm and the likelihood of such harm
occuring(i.e. risk characterization).
Risk characterization shall be performed in accordance withthe
procedures in the Superfund Public Health Evaluation Manualand U.S.
EPA "Risk Assessment Guidelines of 1986." Both arebeing provided to
your consultant in a separate transmittal.
Where available data are found to be inadequate for addressing
therequirements of the Endangerment Assessment Guidance, the PEA
shall notethe data deficiency so that it can be addressed 1n
subsequent Tar Lake RIdata collection activities. This will help
ensure the utility of therevised PEA In planning for these
additional site characterization studies.
In addition, the modified PEA will need to fully and properly
addresseach of the U.S. EPA comments. In Instances where the U.S.
EPA com-ment provides alternate language, the U.S. EPA alternate
languageshould be used, verbatim, in the revised PEA, wherever the
affectedlanguage from the PEA may have appeared.