vc/EPA
United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
Publication 9345.0-051
May 1992
ECO Update
Office of Emergency and Remedial Response
Hazardous Site Evaluation Division (OS-230)
Intermittent Bulletin
Volume 1, Number 4
Developing A Work Scope For
Ecological Assessments
This Bulletin is intended for Remedial Project
Managers (RPMs), to help them plan and manage
ecological assessments of sites as part of the Remedial
Investigation and Feasibility Study (RI/FS) process.1
As used here, the generic term work scope describes
the process of specifying the work to be done for the
ecological assessment, as part of the overall RI Work
Plan. The term encompasses project scoping, devel-
opment and approval of the Work Plan, and prepara-
tion of the Statement of Work (SOW) for contractors
(at Fund-lead sites).
The outcome of a successfully executed work
scope should be an ecological assessment that in-
cludes four essential components: problem formula-
tion, exposure assessment, ecological effects assess-
ment, and risk characterization.2 A work scope should
also provide for dose oversight of individual tasks.
This will ensure that the assessment accomplishes its
objectives within reasonable budget and schedule
limitations.
Need for Clarity, Specificity, and
Completeness
SOWs and Work Plans should clearly state the
studies needed at each phase of the assessment. In addi-
tion, they should include other parameters concerning an
assessment, such as sample collection, data analysis, and
reports. Specifically, SOWs and Work Plans should de-
scribe:
Which studies should be conducted;
Why they should be conducted;
When and where they should be conducted;
What data should be collected;
How samples should be collected, handled, and ana-
lyzed;
How data should be evaluated; and
What reports should be produced.
IN THIS BULLETIN
The Role Of The Biological Technical Assistance
Group 2
Points To Consider In Developing A Work Scope 2
Elements Of An Ecological Assessment Work Scope ....4
Ensuring Contractor Capability To Do Work 7
Review Of Interim And Final Products 8
Sample Work Scope 9
Conclusion 9
Appendix n
1 Although the primary focus of this document is on the RI/FS
process, On-Scene Coordinators may find much of the informa-
tion useful in evaluating sites during the removal process.
Ecological Assessment of Superfund Sites: An Overview (ECO Update
Vol. 1, No. 2).
ECO Update is a Bulletin series on ecological assessment of Superfund sites. These Bulletins serve as supplements to Risk Assess-
ment Guidance for Superfund, Volume U: Environmental Evaluation Manual (EPA/540-1-89/001). The information presented is
intended as guidance to EPA and other government employees. It does not constitute rulemaking by the Agency, and may not be
relied on to create a substantive or procedural right enforceable by any other person. The Government may take action that is at
variance with these Bulletins.
-------
Preparing a clear, specific, and
thorough SOW will avoid such
problems as the following:
Too much work,
Too little work,
Incorrect work, and
Inadequate QA/QC.
The work scope should also detail how decisions
will be made about the need for additional studies.
Preparing a clear, specific, and thorough SOW will
avoid such problems as the following:
Too much work. In the absence of clear direction, a
contractor may do considerably more work than is
required to characterize the ecological risks at the
site, wasting both time and money. The studies could
be valid, well-designed, and complete, but unneces-
sary given the nature of the site and its contaminants.
Too little work. An improperly designed study can
result in inadequate attention to potentially impor-
tant habitats or species associated with the site, too
few sampling stations to characterize a habitat, or too
few data points for meaningful statistical analysis.
Such shortcomings could result in the need to con-
duct additional studies and cause delays in produc-
ing an acceptable RI/FS.
Incorrect work. If the SOW is not specific enough as
to what work is needed or what the objectives of the
studies are, the contractor may conduct studies that
fail to meet the needs of the RI/FS decision-making
process. In this case, valuable time may be lost as the
correct studies are rescheduled.
Inadequate QA/QC. If the SOW does not specify
data quality objectives (DQOs), the data may not
meet the level of quality required to make decisions
on risk or remedial actions. As above, a delay in the
RI/FS process may result.
The Role Of The Biological Techni-
cal Assistance Group
Most EPARegjonal Offices haveestablished groups
of biologists to advise site managers on ecological assess-
ment in the RI/FS process from the Work Plan stage
onward. These Biological Technical Assistance Groups
(BTAGs)3 provide valuable help in the development of a
work scope.
RFMs should contact the Regional BTAG Coor-
dinator as early in the process as possible, certainly
before the Work Flan has been developed. The RPM
should provide appropriate documentation on the site and
its contaminants to BTAG members before the group meets
to discuss the site. In addition, the BTAG may find a brief
oral presentation on the site and its history helpful at this
time. (A future ECO Update will provide guidance on how
to provide the BTAG with useful information in this initial
briefing.) Following this initial review of site data, the
BTAG can make recommendations on the need for studies
to characterize the ecological risks posed by the site. When
the draft Work Plan has been developed, BTAG review
may elicit further helpful comments.
The BTAG should also be consulted when interim
products (reports, data summaries, etc.) are delivered.
Based on the data in such a product, the BTAG may
recommend modifications to the original work scope.
Because this kind of "mid-course correction" can save a
project time and money, the RPM is well advised to sched-
ule time for such reviews in the Work Plan.
Points To Consider In Developing A
Work Scope
Definition of Objectives
The work scope for the ecological assessment of a
Superfund site requires an overall objective to provide the
assessment with direction. When an assessment has a clear
objective, the RPM can readily determine which studies
will further the assessment. For example, at a site where
chemicals from mine tailings contaminated the cold moun-
tain streams that flow through the area, the work scope had
for one of its objectives to determine whether resident fish
had suffered adverse impact. Consequently, the work
scope specified studies that concerned fish and their envi-
ronment. These studies included aquatic toxicity tests, a
3These groups are sometimes known by different names, depending on the Region, and not all Regions have established BTAGs. Readers
should check with the appropriate Superfund manager for the name of the BTAG coordinator or other sources of technical specialized
facilities, and specialized equipment necessary to carry out the work. If not, qualified subcontractors should be sought for those tasks where
their qualifications are needed.
May 1992 Vol. I, No. 4
ECO Update
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fish survey, and bioaccumulation4 studies using resident
fish.
The overall assessment objective may be clear
from the outset, based on data from previous studies or on
an evaluation of the concentrations and known effects of
site contaminants. More likely, some preliminary studies,
including a site visit and collection of screening-level data,
will be needed to identify and specify the objective of the
ecological assessment. Where possible, these preliminary
studies should incorporate the need for future work.
Just as an ecological assessment gains direction
from having an overall objective, each study that the work
scope specifies also should have a dear objective, such as
filling a data gap or testing a hypothesis about the effects of
the site's contaminants on resident organisms. By stating
a study's objective, an RPM provides guidance for design-
ing the study. For example, the work scope for the mining
site described above called for aquatic toxicity testing to
determine whether the water was toxic to freshwater fish
that thrive at low temperatures. This study objective
provided specific direction in planning the toxicity tests.
Assessment Design
The work scope lays out the design for an ecologi-
cal assessment. Assessment designs vary tremendously
from site to site depending on:
The objective of the assessment;
The size, location, and accessibility of the site;
The site's ecologywhat is already known and what
needs to be known; and
The site's contaminant history.
In an ecological assessment, the individual studies
are the pivotal elements. If the overall objective gives an
ecological assessment a purpose, the studies are the ve-
hicles by which it attains its purpose. Studies can include
chemical analyses of media or biota, toxicity testing of
laboratory or resident organisms, biological field studies,
and analyses of organisms' physiological or pathological
condition. However, because a work scope indicates only
those studies necessary for assessinga specific site, any one
assessment need not include all of these types of studies.
The assessment design specifies not only which studies to
perform but also the level of effort for each. For example,
the work scope developed for the mining site described
above included toxicity testing, but only of one medium
(surface water) and with only one type of test organism
(fathead minnow). At another site, toxicity testing might
include evaluation of soil, sediment, and surface water
using several different organisms.
The complexity of an ecological assessment makes
it essential that trained ecologists have responsibility for its
design. The RPM can consult the BTAG for advice as to
which media to analyze, which studies to perform, and at
what level of effort. The RPM can include this information
in the SOW. As discussed below, since the contractor has
responsibility for developing the Work Plan from the
SOW, the RPM needs to consider whether the contractor's
staff has the required expertise. After a contractor has
prepared the Work Plan, the BTAG can review it and
advise the RPM whether or not to approve it.
The phased approach ensures
that:
Only the necessary work will
be done, and
All the necessary work will be
done.
Phased Approach to Task Implementation
For most sites, a phased approach with expert
review at each phase results in the most efficient use of
resources. With the phased approach, data or observations
from one phase determine whether further studies are
needed to meet the assessment's objectives and, if so, what
these studies are. At some sites, the phased approach
might result in a low level of effort adequately characteriz-
ing ecological risks. At others, the phased approach might
indicate that the assessment should be expanded to in-
clude studies of specific habitats or contaminants in order
to evaluate the risks. At still other sites, the phased ap-
proach could identify areas originally not considered at
4 Bioaccumulation is the accumulation of a substance in an organism's tissues as a result of respiration, absorption, or feeding.
ECO Update
May 1992'Vol.1, No. 4
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risk. In this case, the RPM would want to expand the work
scope to include an assessment of the newly identified
area. Review of interim products, such as a report on the
levels of contaminants of concern or a field survey of
resident species, can contribute to the phased approach.
Careful review of interim products can help to ensure that
the assessment remains focused on those studies most
important for evaluating the site's ecological effects.
To summarize, the phased approach ensures that:
Only the necessary work will be done, and
AH the necessary work will be done.
The value of the phased approach can sometimes
be outweighed by other factors. For example, seasonality
affects when certain types of studies, such as floristics
surveys, can occur. In some cases, budgetary restrictions
and time constraints may be incompatible with the phased
approach. RPMs may need to consider such factors when
planning studies.
In practical terms, the phased approach requires
an RPM to decide when a contractor should proceed from
one task to the next and whether the contractor should
proceed with one alternative task or another. In making
these determinations, the RPM interprets information from
completed studies. The BTAG can assist the RPM in
identifying criteria appropriate for evaluating data. (See
Figure 1.)
An ecological assessment
should be designed to contribute
to remedial decisions at the site.
As an example of the phased approach, consider
the following hypothetical case. (See Figure 1.) An RPM
has a field reconnaissance done in order to identify and
map potentially exposed habitats at a site. The RPM then
uses the results of this study to decide on the numbers and
placement of sampling stations for initial chemistry data.
After the first round of sampling for contaminant levels at
these stations, the chemistry data indicate that contaminant
levels are high enough in some areas of the site to warrant
collection of biological data from the field, along with
additional data on site chemistry. The field data collected
indicate the advisability of toxidtytestingatcertainstations,
but not at others. In other parts of the site, the low level of
contaminants indicate that no further biological
investigation is required. Thus, in this hypothetical
example, use of the phased approach results in the areas
most in need of study receiving the most attention.
An ecological assessment
involves problem formulation,
exposure assessment, eco-
logical effects assessment, and
risk characterization.
Relating Ecological Information to
Remedial Decision-Making
While an ecological assessment of a Superfund site
might extend our knowledge of the environment and the
effects of contaminants on it, the assessment is not in-
tended as a research project. Rather, it should be designed
to contribute to remedial decisions at the site. Ecological
assessments serve this function when they determine
whether remediation is needed, indicate the conditions (if
any exist) requiring remediation, suggest technologies for
achieving remediation, and /or estimate the environmen-
tal effects of proposed remedial alternatives. At the earliest
stages of Work Plan development, the RPM and BTAG
should consider what types of ecological information will
contribute to remedial decisions. For example, the site
manager may need to know:
If remediation goals are protective of environmental
receptors,5
If ecological risk considerations will affect the defini-
tion of the area to be remediated,
If special measures need to be taken during
remediation to protect natural habitats, and
. What monitoring will be needed to ensure protection
of environmental receptors during and after
remediation and to evaluate the effectiveness of re-
medial actions.
s Receptors are individuals, populations, or communities/
habitats that may be exposed to a contaminant.
May 1992 Vol. 1, No. 4
ECO Update
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Field survey identifies locations A-L as potentially exposed habitats requiring additional chemical analysis
"A"
B
K
Level of contaminants high enough only at locations E-L to
warrant collection of additional field and chemical data.
H
I
Results of additional field
and chemical studies
indicate advisibility of
toxicity testing at locations
I, J, K, and L
Figure 1. The Phased Approach
As this hypothetical ecological assessment
illustrates, the phased approach results in the
areas most in need of study receiving the
most attention.
Questions such as these should form part of the
initial scoping session, where the RPM and the BTAG
select appropriate studies and study designs.
Elements Of An Ecological Assessment
Work Scope
As described in Ecological Assessment ofSuperfund
Sites: An Overview (ECO Update Vol. 1, No. 2) an ecological
assessment involves problem formulation, exposure as-
sessment, ecological effects assessment, and risk character-
ization. To ensure that an assessment fulfills its objectives,
the work scope should use its elements to accomplish these
tasks. In addition, the work scope should identify data
quality indicators to ensure that established DQOsare met.
Problem Formulation
Problem formulation defines the assessment's ob-
jectives and also involves a thorough description of the
site. This qualitative description must occur before decid-
ing oh any substantial quantitative work.
An initial site description should include citations
from existing site literature (such as the Preliminary As-
sessment, Site Inspection, or any studies conducted in
support of removal actions) relating to site history, physi-
cal features of the site, known or suspected contaminants,
habitats on or near the site, species expected at or near the
site, and known or anticipated effects of site contaminants
on receptors. Investigators should determine whether
threatened or endangered species are known or suspected
to occur at or near the site. Descriptions of potentially
affected habitats should include as much detail as possible.
For instance, stream habitats vary considerably depending
on stream depth and width, type of stream bottom, and
types of vegetation in and adjacent to the stream. Informa-
tion pertaining to these types of characteristics could affect
both the kinds of studies required to evaluate possible
effects and the level of effort needed to conduct the studies.
This qualitative description of the site helps to
indicate whether further studies are needed and, if they
are, what these studies should be. For example, if scientific
ECO Update
May 1992 Vol. 1, No. 4
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literature or databases indicate that a site's contaminant
concentrations consistently fall below levels likely to cause
adverse ecological effects, additional analyses may be un-
necessary. On the other hand, if contaminant concentra-
tions suggest a need for further investigation, the initial site
description may identify potential exposure routes useful
in targeting the additional studies to media and areas of
greatest concern. Targeting studies makes the most effi-
cient use of the time and money available for the ecological
assessment.
A site visit should form part of the initial site
description phase. In addition, the RPM may decide to
characterize the site's ecology further by conducting lim-
ited field studies. These studies could include aerial pho-
tography, evaluation of habitats' suitability for wildlife,
functional evaluation of wetlands,6 qualitative or semi-
quantitative examination of the environment for evidence
of stress (e.g., stressed or dead vegetation, bare soil and
erosion, dominance by pollution-tolerant species), and
field verification of the presence or absence of key species.
At some sites, the existence of site descriptions made prior
to contamination may enable the RPM to assemble a "be-
fore and after" picture of the site.
Based on the information developed in this initial
site description, the investigator (under the direction of the
RPM and with BTAG consultation) should specify:
The receptors (habitats and species) most likely to be
exposed to site contaminants,
The contaminants most likely to be of ecological
concern,
The ecological effects most likely to be important
with regard to the site, and
The studies needed to characterize actual or potential
adverse effects associated with site contaminants
and, where applicable, the hypothesis that the study
will test.
Exposure Assessment
Since exposure assessment quantifies the actual or
potential exposure of receptors to contaminants, the work
scope must plan for studies that gather appropriate data on
both receptors and contaminants. Evaluation of chemical
and biological data will indicate which receptors and
contaminants are appropriate subjects of study and how
best to evaluate exposure at a particular site. And, as in all
other decisions of this type, the RPM can consult the BTAG
before committing resources.
The work scope can either specify receptors for
exposure studies or set criteria for selecting receptors.
Receptors studied in the exposure assessment could be
chosen from among the site's biota, or surrogate species
(e.g., standard test species) might be used. Resident spe-
cies used as receptors can be selected from among those
most likely to suffer adverse effects from site contaminants
or those considered representative of or critical to the
ecosystem. Alternatively, the work scope could specify
receptors for further study because they are of concern for
statutory or other reasons (e.g., those species protected
under Federal law). When the RPM has satisfied these
criteria for choosing receptors, he or she can then consider
which of the species are most amenable to rapid and
inexpensive field evaluation. Field, laboratory, and litera-
ture studies conducted in the Problem Formulation phase
can also aid in selecting and characterizing receptors. The
exposure assessment should include information on feed-
ing habits, life history, and habitat preferences of receptors.
To study exposure to contaminants, the work scope
might include additional chemical analyses and the mea-
surement or estimation of exposure point concentrations.
Chemical analysis of plant and animal tissues is one useful
technique for determining whether exposure to contami-
nants has taken place. For contaminants known to
bioaccumulate, analysis of tissues from organisms repre-
senting different trophic levels (e.g., plant, herbivore, car-
nivore) also permits measurement of dietary exposure for
species that feed on contaminated organisms. Biochemi-
cal, physiological, and histological studies can also pro-
vide information about exposure of receptors to site con-
taminants.
The work scope could also specify studying expo-
sure by means of fate-and-transport models. Fate con-
cerns the ultimate chemical disposition of a contaminant,
such as remaining stable, undergoing photodegradation,
or combining with another substance. Transport, or mi-
gration, refers to the movement of a contaminant from one
medium to another, from one location to another within
the same medium, or into biota. Site characteristics, con-
taminants' physical and chemical properties, and
' A functional evaluation of a wetland determines the importance of the wetland for such values as wildlife habitat, pollution abatement,
and flood control. This type of study helps to establish the value of a particular wetland as it relates to the need for remediation. Another
type of study, a wetland delineation, defines the boundaries of a wetland based on soil type, vegetation, and hydrology. The delineation
aids in the selection and evaluation of remedial alternatives. Site managers should consult with their BTAGs to determine which of these
studies are appropriate, if at all, and when they should be conducted.
May 1992 Vol.1, No. 4
ECO Update
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bioaccumulation studies provide information useful in
predicting the fate and transport of site contaminants.
Ecological Effects Assessment
Ecological effects assessment links concentrations
of contaminants to adverse effects in receptors. Literature
reviews, field studies, and laboratory studies provide the
information for making this link. However, the ecological
assessment of a site may not require all three of these types
of studies.
Field studies of populations and communities7
support ecological effects assessment by providing infor-
mation on the condition of populations of resident species
and on any contaminant-related changes in ecological
communities. In their focus on resident populations, field
studies play a central role in identifying receptors. Such
studies also can allow investigators to collect samples for
laboratory analysis.
Field studies focus on natural environments, in-
cluding freshwater, marine, or terrestrial environments.
Aquatic field studies can include surveys of benthic (bot-
tom-dwelling) organisms and surveys of organisms in the
water column. Marine studies can also include surveys of
coastal and tidal areas. In terrestrial environments, field
studies may focus on vertebrates, invertebrates, or vegeta-
tion. An RPM also may need to conduct field studies in
such human-managed environments as residential neigh-
borhoods and other landscaped areas, since some wildlife
species make use of these areas for all or part of their life
cycle.
Generally, habitats that are potentially or actually
exposed to contaminants require some field study. Con-
sulting with the BTAG will enable the RPM to select the
methods and level of effort appropriate to the site and its
remedial objective. Whenever possible, the work scope
should specify standard or commonly accepted field meth-
ods. A future ECO Update will provide information about
field studies useful at Superfund sites.
Level of effort depends on the choice of qualita-
tive, semi-quantitative, or quantitative studies. In some
cases, qualitative studies will adequately describe the habi-
tats and species at risk. However, most sites with sus-
pected adverse effects will require some semi-quantitative
or quantitative studies. For example, at one site a semi-
quantitative approach for evaluating effects of stream pol-
lution might sufficiently characterize differences in species
composition between contaminated and uncontaminated
areas of a stream. But another site might require a more
detailed quantitative analysis to discern such differences.
An important task in preparing a work scope
involves coordinating different types of studies. In an
ecological effects assessment, simultaneous collection of
site chemistry data and biological field data allows the
analysis to show clearly whether a correlation exists be-
tween contaminant presence and ecological effects.
Toxicity tests (bioassays) constitute a major type of
study used in assessing ecological effects at Superfund
sites. Toxicity tests expose selected organisms to water,
soil, or sediment from the site to determine whether the
medium adversely affects the organisms. Most commonly,
technicians perform these tests in laboratories using stan-
dard test organisms. However, toxicity tests also can occur
on-site and can use resident organisms.
Especially for a site with only one or a few con-
taminants, toxicity tests can contribute to the weight of
evidence linking the contaminants to biological effects.
Specifically, while chemical analyses indicate the presence
of contaminants, they do not indicate whether contami-
nants are bioavailable.8 In order to have a toxic effect, a
contaminant must be both bioavailable and toxic. The
relationship between toxicity and site contaminants is less
easily interpreted for sites with a more complicated con-
taminant picture.
The work scope should coordinate the collection
of site chemistry data and toxicity data. When the work
scope specifies that toxicity tests will occur in the labora-
tory, field scientists should collect samples for chemical
analyses and toxicity tests at the same time and in the same
place. When the work scope calls for in situ toxicity tests,
chemical sampling should happen concurrently and at the
same locations. In this way, analysis of the data can most
clearly evaluate correlations between toxicity results and
contaminant levels.
Consulting closely with the BTAG can help the
RPM decide which tests are appropriate and the specific
conditions under which to conduct the tests. A future ECO
Update will focus on using toxicity tests in ecological as-
sessments.
Risk Characterization
In ecological assessments, risk characterization
evaluates the evidence linking site contaminants with ad-
verse ecological effects. To characterize risk, the investiga-
7 A population is a group of organisms belonging to the same species and inhabiting a contiguous area. A community consists of populations
of different species living together.
8 Bioavailabihty is the presence of a substance in a form that organisms can take up.
ECO Update
May 1992 Vol. I, No. 4
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tor evaluates all of the chemical and biological data relating
to the site, comparing the results of the exposure assess-
ment with the results of the ecological effects assessment.
In particular, fate and transport studies can provide evi-
dence of links between site contaminants and observed or
predicted effects.
Also relevant to risk characterization are the re-
sults of the chemical analyses of media, toxicity testing,
and field studies. At some sites RPMs will have had these
studies conducted along contaminant gradients. Where
risk characterization establishes a link between contami-
nants and adverse effects, it should also describe the quali-
tative or quantitative ecological significance of these ef-
fects.
A successful work scope is one that correctly an-
ticipates the types of studies that will provide the data
needed for risk characterization.
The results of an ecological
assessment support the re-
medial decision-making process
only if the data are scientifically
defensible.
Quality Assurance
The results of an ecological assessment support
the remedial decision-making process only if the data are
scientifically defensible. Usually, this means that the data
should be (1) accurate and (2) amenable to statistical analy-
ses (for quantitative studies). Data quality objectives are
qualitative and quantitative statements of the overall level
of uncertainty that a decision maker is willing to accept.
Consequently, data quality objectives reflect the statistical
design of the study and the level of significance needed to
support any conclusion that might be drawn from the
study. For example, the SOW should specify a sample size
large enough to account for natural variability to ensure
that DQOs are met In reviewing the Work Plan, the RPM
should ensure that minimum sample sizes are specified for
statistically valid analyses, that significance criteria meet
the needs for remedial decision making, and that quality
control procedures are in place to ensure accuracy and
precision.
Before approving a Work Plan,
the RPM should make certain that
the contractor has the trained
personnel, specialized facilities,
and specialized equipment ne-
cessary to carry out the work. If
not, qualified subcontractors
should be sought for those tasks
where their qualifications are
needed.
Quality assurance is the set of procedures that
ensure that the quality of data meets the needs of the user.
The Work Plan establishes quality assurance for field work
and laboratory analyses by specifying criteria for such
items as sample collection, sample handling, and numbers
of replicate analyses. Selecting standard methods speci-
fied in EPA or other Federal agency manuals (subject to
EPA approval), when these methods are appropriate, can
provide confidence of a stated level of quality assurance
because they have built-in quality control activities.
Laboratories that conduct standard toxicity tests,
such as those required under the National Pollutant Dis-
charge Elimination System (NPDES), have in place quality
control procedures that are readily subject to review and
audit Contractors experienced in conducting field studies
should also have standard procedures for ensuring accu-
racy and reproducibility in their work. As an example of
quality control in a field study, a survey of benthic inver-
tebrates could require an independent taxonomist to clas-
sify a randomly selected sub-set of the organisms identi-
fied by the study's field or laboratory staff. '
When the work scope specifies clear and appropri-
ate quality assurance procedures, the data collected should
satisfy the specified data quality indicators of precision,
accuracy, representativeness, completeness, and compa-
rability.
Ensuring Contractor Capability To Do
Work
Ecological studies require trained personnel, and
some studies also require specialized facilities and equip-
ment. Before approving a Work Plan, the RPM should be
May 1992 Vol.1,No.4
ECO Update
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satisfied that the contractor proposing to carry out the
work can do so. If not, qualified subcontractors should be
sought for those tasks where their qualifications are needed.
Personnel
In selecting a contractor, an RPM must look for a
direct match between contractor qualifications and the
scope of work. To this end, the RPM should request
information on the specific training and experience of
proposed individuals with respect to the specific tasks to
be undertaken. For example, if a Work Plan calls for
sampling benthic invertebrates in a stream, those conduct-
ing the study should:
Be familiar with the types of equipment (e.g., Surber
sampler, artificial substrates)appropriate to thestudy
site;
Know how and where to collect samples (e.g., what
kinds of stream bottoms support which species);
Know what kinds of environmental data to collect
along with the biological and chemical samples (e.g.,
water temperature, pH, dissolved oxygen, hardness);
and
Have the requisite taxonomic expertise to identify
the organisms (principally the larval stages of in-
sects) collected.
On the other hand, these same individuals may
lack qualifications for conducting other types of studies,
such as wetland assessments or the collection of small
mammals for tissue analysis. Although some experienced
biologists have developed considerable expertise working
in a wide variety of habitats and with a broad range of
species, many others are specialists in their fields and do
not know the details of conducting studies outside their
specialty. Consequently, the RPM must ask for evidence of
specific individuals' capabilities to carry out proposed
tasks. This evidence can consist of results of similar studies
conducted in the past These results should demonstrate
that the contractor performed studies correctly and that the
resulting data served its intended purpose.
Facilities and Equipment
The RPM also should require a contractor to dem-
onstrate capability in terms of any specialized facilities and
equipment needed to conduct the studies selected for a
particular site. For example, most of the toxiciry tests used
to evaluate aquatic systems are standard procedures de-
veloped for NPDES. Many States have certification pro-
grams for laboratories that conduct NPDES toxicity tests.
If the work scope calls for such tests at a site, the RPM can
ask that the contractor use a laboratory certified in at least
one State (if possible, the State where the site is located),
and that the laboratory show proof that it has conducted
the same or similar tests in the recent past. Alternatively,
where a State and its neighboring States have no certifica-
tion program, the RPM can obtain the name of an appropri-
ate laboratory from the State agency charged with regulat-
ing NPDES permittees. In the case of field sampling, the
BTAGor Regional field biologists can evaluateacontractor's
capabilities.
In all cases, contractors must possess both the
appropriate equipment and staff trained on that equip-
ment. For instance, a commonly used method for collect-
ing fish involves electroshock equipment that stun the fish,
causing them to float to the surface. Electroshock equip-
ment ranges in size from small backpack units to large
boat-mounted units. For both safety and efficacy, it is
essential to use the right size of equipment manned by a
crew familiar with its operation and safety requirements.
Review Of Interim And Final Products
In keeping with the suggested phased approach,
the RPM should plan for BTAG review of interim products
such as initial site descriptions, initial field surveys, and
reports on specific studies such as toxicity test results or
field data. Such reviews form the basis for revising the
work scope to account for the new findings.
In addition to the interim products mentioned
above, the RPM should have the BTAG review the draft
Work Plan and the draft ecological assessment before the
contractor proceeds with the final version. With regard to
the draft ecological assessment, the RPM should particu-
larly request the BTAG to comment on the quality of
studies and the validity of their findings. The RPM will
also want to know whether the data support any conclu-
sions about proposed remedial actions at the site.
Sample Work Scope
The Appendix presents an example of the kinds of
components likely to occur in a typical work scope. Of
course, work scopes designed forparticular sites will differ
significantly from the general one in the Appendix. An
RPM will find it necessary to tailor the work scope to the
specific conditions and objectives at an individual site.
ECO Update
May 1992 Vol.1,No.4
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The example in the Appendix also demonstrates
how BTAG review of interim products can alter the scope
and level of effort for succeeding tasks. The example
always states that products are subject to review and
approval by the site manager, because the BTAG has no
official authority to approveordisapprovecontractorwork.
Nevertheless, wherever appropriate, the RPM should ask
the BTAG for review and advice on each product. In
scheduling a project, RPMs need to allow time for the
review process. In fact, some Regional BTAGs require a
minimum review period.
In addition to the general work scope in the Ap-
pendix, RPMs in several Regions have available to them
generic work statements or other guidance material pre-
pared by their BTAGs. RPMs should check with the BTAG
coordinator in their Region to obtain any such guidance.
Conclusion
This Bulletin has summarized the issues an RPM
needs to address in developing work scopes for the eco-
logical assessment of Superfund sites. Because every site
presents a unique combination of study problems, RPMs
should consider the expert advice of BTAG members as an
essential part of the planning process for these assess-
ments. These specialists should be consulted as early as
possible in the planning stages for a site, and should
remain involved in the planning and oversight throughout
the life of the project. By involving the BTAG in this way,
the RPM can be assured that ecological as well as human
health effects will receive the full attention called for in the
law and in Agency policy directives.
Figure 2 Ordering Tasks in an Ecological Assessment
An investigator can conduct simultaneously some of the tasks that a Work Ran details for an
ecological assessment. As indicated below, which tasks can occur simultaneously will vary somewhat
with the site. Note that She 2 does not require Task 6 (Final Data Collection), indicating that Task 5
gathered all the data necessary for an ecological assessment
Sttel
Site 2
Task 2
Site Reconnaissance Visit
Tasks
Data Collection
Task 6
Final Data Collection
Task 7
Risk Characterization
Task 8
Report Preparation
Task9
Report Revision
Taskl
Site Description
Site Reo
I
Task 3
Site Screening
Tas*7
Risk Characterization
Tas
Draft of V
1
TaskS
Data Collection
I
Ta
Report P
I
Task 9
Report Revision
Task 2
mnaissance Visit
*4
VorkPlan
ska
reparation
May 1992 Vol. 1, No. 4
W
ECO Update
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APPENDIX
SUGGESTED TASKS IN PLANNING AND EXECUTING
AN ECOLOGICAL ASSESSMENT
The following tasks can help a contractor in assembling an acceptably detailed and focused ecological assessment.
Wherever possible, these tasks should be coordinated with the human health assessment and any hydrogeologic investiga-
tions.
A site's ecological assessment may not require all of the tasks. For example, with site description (Task 1) and the
reconnaissance visit (Task 2) complete, the RPM may decide that the Work Plan can be drafted (Task 4) without any further
site characterization (Task 3).
Note also that an investigator can conduct certain tasks simultaneously rather than sequentially, greatly enhancing
the efficiency of the process (Figure 2). Precisely which tasks can occur simultaneously and which the investigator must
conduct sequentially depend upon the site.
Task 1. Site Description
Purpose: Preliminary screening of the extent of contamination and the potential for adverse effects
Description: Qualitatively describe site based on existing data from the Preliminary Assessment, Site Inspection, and
other sources, including:
1. Physical description of the site and its surroundings, including photos and detailed maps
2. Nature and extent of contamination by medium and contaminant type
3. Site-associated habitats potentially exposed to contaminants
4. Initial toxirity assessment of site contaminants with respect to environmental receptors, including
comparison to criteria and other benchmarks
Submit interim report to site manager for review.
Task 2. Site Reconnaissance Visit
Purpose: Gather first-hand expert opinion of site's condition and suggestions about what, if any, studies are needed
Description: If authorized by site manager, prepare plan for site reconnaissance, including:
1. Chemical and biological data needed for more complete initial site description
2. Methods to be used to collect necessary data
3. Criteria for deciding whether and what future studies might be necessary
Submit reconnaissance plan to site manager for review.
Task3. Site Screening
Purpose: With limited studies, identify and characterize habitats and characterize exposure and ecological effects.
[For some sites, information will suffice for risk characterization]
ECO Update 11 May 1992 Vol. 1, No. 4
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Description: If authorized by site manager, further characterize site based on field observations, including, as
appropriate:
1. More detailed habitat identification and evaluation
a. Suitability for wildlife, including an endangered species consultation with State and Federal agencies
b. Ecosystem value and function (e.g., wetland functional analysis)
2. Qualitative and semi-quantitative surveys of flora and fauna
3. Toxicity tests
4. Additional chemical sampling
5. Identification of appropriate reference sites for comparison to each potentially exposed habitat
6. Simple modeling of transport and exposure
Submit interim report to site manager for review.
Task 4. Draft of Work Plan
Purpose: Develop a plan that will provide any additional information about exposure and ecological effects that is
needed to characterize risk
Description: Draft detailed Work Plan for any further site investigations needed, including overall assessment objective
and, as appropriate:
1. Qualitative, semi-quantitative, and quantitative surveys of flora and fauna in potentially
exposed habitats and reference sites
2. Chemical sampling of media and biota in potentially exposed habitats and reference sites
3. Laboratory and in situ toxicity testing
4. Tissue analyses, enzyme studies, and bioaccumulation studies
5. Simple modeling of fate and transport
For each proposed study above, provide:
a. Objectives of the study, effects to be measured, and relevance to overall risk assessment objectives at
the site
b. Proposed field or laboratory methods and their risk-based detection limits (where appropriate), with
appropriate references to Agency guidelines or other source
c. Criteria for determining sampling locations, expected sampling locations (including detailed maps),
sampling dates, and sample sizes
d. Benchmark, or background values, where appropriate
e. Statistical methods to be used and data quality indicators to meet statistical significance criteria
f. Quality assurance procedures and quality control techniques.
Submit Work Plan to site manager for review and approval. Revise per site manager's direction.
May 1992 Vol. 1, No. 4 22 ECO Update
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Tasks. Data Collection
Purpose: Gather necessary data regarding exposure and ecological effects
Description: Conduct those studies approved by site manager for immediate execution. Submit interim reports to site
manager for review.
Task 6. Final Data Collection
Purpose: Based on findings of studies conducted, identify and collect any final data needed to assess exposure and
ecological effects
Description: Revise Work Plan per site manager's direction. Conduct next phase of studies as approved by site
manager. Submit interim reports to site manager for review. Repeat this step as needed. Task 6 is an
iterative process that will lengthen or shorten, depending on the results of studies.
Task 7. Risk Characterization
Purpose: Validate the data and their interpretation, and characterize risk.
Description: Prepare the following for review by site manager:
1. Summary of biological and chemical data
2. Detailed outline of ecological assessment
Task 8. Report Preparation
Purpose: Prepare data for presentation.
Description: Prepare draft ecological assessment.
NOTE: Depending on the scope and level of effort decided on by the site manager, not all of the elements listed
below may appear in a given assessment For instance, not all sites will require toxicity testing or the full
array of quantitative field studies. The following outline should be modified to account for the studies
actually undertaken at the site with the approval of the site manager.
1. Initial site description and potential receptors (include detailed maps wherever appropriate)
a. Physical description of the site
b. Nature and extent of contamination by medium and contaminant type
c. Potentially exposed habitats
(i) Surface water habitats
(ii) Wetlands
(iii) Terrestrial habitats
(iv) Sensitive or critical habitats
d. Potentially exposed species
(i) Vegetation
ECO Update 13 May 1992 Vol. 1, No. 4
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(ii) Invertebrates
(iii) Vertebrates
(iv) Special concern species
2. Selection of contaminants, species, and ecological effects of concern
a. Contaminants of concern and rationale for selection
b. Species of concern and rationale for selection
c. Ecological effects of concern, acceptable and unacceptable levels of effects, temporal and spatial scales
of concern, and rationale for selection
3. Exposure assessment
a. Sources and exposure pathways of contaminants of concern
b. Fate and transport analysis
c. Exposure scenarios
d. Estimated exposure point concentrations by habitat, species, and exposure scenario
e. Uncertainty analysis
4. Ecological effects assessment
a. Known effects of contaminants of concern (from literature)
b. Site-specific toxicity testslaboratory and in situ
c. Existing toxicity-based criteria and standards
d. Uncertainty analysis
5. Risk Characterization
a. Observed adverse effects in potentially exposed habitats compared to reference sites
(i) Mortality and morbidity
(ii) Vegetation stress
(iii) Habitat degradation
(iv) Presence or absence of key species
(v) Population assessment of key species
(vi) Community indices
(vii) Ecosystem function, such as decomposition or nutrient recycling
b. Analysis of contaminant concentrations in relation to observed adverse effects
c. Analysis of bioaccumulation studies
d. Analysis of toxicity test results in relation to observed adverse effects
May 1992 Vol. 1, No. 4 14 ECO Update
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e. Comparison of estimated exposure point concentrations with criteria and standards
f. Comparison of estimated exposure point concentrations with toxicity data and / or toxicity values from
literature, as appropriate
g. Likely ecological risks associated with present and future land use scenarios
h. Ecologically relevant ARARs
i. Ecological considerations in selecting remedial alternatives (including no action)
j. Uncertainty analysis
Submit draft ecological assessment to site manager for review.
TaskB. Report Revision
Purpose: Prepare final presentation of ecological assessment
Description: Revise draft ecological assessment per site manager's review comments and submit final ecological
assessment for inclusion in RI /PS.
ECO Update 15 May 1992 Vol. 1, No. 4
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