[USACE] Risk Assessment Handbook, Volume II - Z - A-d

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Appendix DHTRW Technical Project PlanningProcess

D.1 lntroduction

The USACE recognizes the need for cost-effective andefficient %/response actions for HTRW projects. The

level of effort required in conjunction with the data col-lection activities for a HTRW project are based on DQOswhich address data quality and quantity requirements of

the users. The recently published Engineer Manual, Tech-nical Project Planning - Guidance for HTRW Data

Quality Design (USACE 1995b) (EM 200-1-2) [referredto as the HTRW Technical Project Planning Guidance in

this appendix] provides project planning guidance todevelop data collection programs and define DQOs for

HTRW sites. This appendix summarizes the four phasesof the HTRW technical project planning - data qualitydesign process with respect to scoping requirements anddata needs for conducting ERAS to support risk manage-ment decisions.

The importance of early planning and getting the riskassessor involved in the planning process at each phase ofthe HTRW response action is emphasized so that dataneeded to assess potential ecological risks will be cost-effectively collected. In identifying data needs for theERA, the risk assessor must fully understand the customergoals, regulatory programs driving the HTRW project

execution and the associated project decision statements(PDs), the study elements for each relevant project phase,and the types of ERA needed by the study elements. AnECSM should be developed and used to focus data needsto evaluate risks for complete exposure pathways to signi-ficant ecological receptors or for the ecosystem to beprotected. In addition, it is important to simultaneouslyconsider the data needs for both the ERA and the human

health assessment throughout the HTRW planning pro-

gram. Both assessment processes will have some dataneeds in common which should be identified so that duplication of effort is avoided.

This appendix is divided into the following sections:

EM 200-130 Jun

Introduction - This section presents the scoand introductory statements.

Overview of the HTRW Technical Project Planing Process - This section summarizes t

four-phases (Phase I through Phase IV) of tdata quality design process.

Roles and Responsibilities - This sectiodescribes the roles and responsibilities of the riassessor in the data quality design process. addition, how this individual uses the skills anexperience of the expert ecologist(s) and/or t

advisory panel such as the BTAG to focus tapproach and the data needs to support sidecisions is described.

Data Needs for HTRW Executable ProjePhases - This section presents a framework f

conceptualizing data needs, establishing darequirements, and the basis for requiring sucdata. Conceptualizing and establishing trationale for data use and data needs are criticelements of the Phase II data quality desigprocess. This section addresses key executab

project phases (i.e., PA/SI and RFA; RI an

RFI; FS and CMS; and RD/RA and CMI)

Summary Conclusions - This section summarizthe role and responsibility of a risk assessor the four-phased HTRW data quality design proess, along with general data needs and stud

elements to support making site decisions each executable phase of the HTRW project.

D.2 Overview of the HTRW Technical ProjePlanning Process

The key to the HTRW technical project planning procefor a response action is understanding the customerneeds and the regulatory requirements/basis for makinsite decisions. Designing the data collection strategrequires professional judgment, scientific decisions, reguatory policy, and the customers goals, to which no sing

person including the data implementor, can easi

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develop a data acquisition strategy to satisfy all users memorandum of understanding (DSMOA); and the Projectneeds. Management Plan (PMP), etc.

The project planning process at various stages requires theinvolvement of appropriate project personnel which con-sist of:

. Decision makers (customer, PM, TM).

. Data users (risk assessors, remedial design engi-neers, compliance specialists, and responsibility-specialists or legal counselors for identifyingpotentially responsible parties [PRPs]).

. Data implementors and reviewers (statistician,sampling specialists [e.g., geologists, hydrogeol-ogists, meteorologists, and biologists], analyticalspecialists [chemists], the health and safety offi-cer, etc.).

The primary products of this data quality design processare the Scope of Work, DQO statements for use in theSampling and Analysis Plan (SAP), and detailed estimatesof costs associated with the selected data collection pro-gram. Other uses for the above outputs could be to formthe basis for developing specific language of or asexcerpts from: the FFA/IAG under CERCLA or the FFCAunder RCRA; Department of Defense and State

1For example, the risk assessor has recommended taking

sediment samples in a swale or runoff channel originating

from a PCB spill area to evaluate the potential risks towetland receptors. The statistician has recommendedusing a grid design with systematic random sampling todetermine where sediment samples are to be collectedfrom the swale. However, a decision has to be made onthe grid size, which is dependent on the variability ofPCB concentrations in previously collected sedimentsamples and the acceptable error rate or level of confi-dence for not being able to detect a hot spot. Therefore,designing the sampling program represents a joint effort

of the Technical Planning Team members. The use ofpreviously collected sediment data and setting a predeter-mined confidence level will involve a management deci-

sion by the PM/regulator and the USACE customer.Input from the risk assessor and statistician include bothprofessional judgment and scientific decisions (i.e., delin-eation of the exposure unit [Eu] or study area, concernlevels to be detected, sampling depth based on potentialexposure pathways for valued receptors to be protected,and the concept of systematic random sampling).

D.2.1 Phase 1 - Develop Project Strategy

Phase I of the technical project planning process involvesunderstanding the customers objectives and requirements

for making site decisions, and putting together a logicalapproach which addresses the questions to be answered orthe decisions needed for specific project phases.

In terms of project execution from site discovery to close-out, key inputs required for decision-making can be morereadily defined after site-specific conditions are generallyunderstood, and the action plan/strategy is developed. Astrategy may be defined as the approach by which actionsand resources are organized, targeted, and used in order tofulfill a mission or meet certain objectives or policies.For example, after having a general understanding of therelease, migration, and transport properties of the COECs,the ecological assessment component of the strategy for atypical CERCLA or RCRA site could be: (1) identify ifsensitive species or valued resources (receptors) existonsite or in the site vicinity; (2) if such receptors exist,collect chemical data to identify the boundary of the areaof ecological concern; (3) ascertain if receptors arelocated within the boundary: (4) recommend no furtheraction if the response to item (1) or (3) is negative;(5) compare chemical data with literature or benchmark(screening) values for the receptors or surrogate species ifthe response to items (1) and (3) is positive: (6) furtherassess the site at the population or community level to

determine the significance of the potential ecologicalimpact if the screening levels or literature values in item(5) have been exceeded, and (7) implement removal,remedial, or corrective action if the ecological risk deter-mined in (5) and/or (6) is judged to be significant

Before development of the site strategy, certain site infor-mation should be gathered for review by the technical

project team. Such information includes, but is notlimited to, regulatory or compliance requirements; pre-viously collected chemical or nonchemical data; history ofoperations: documented incidents or corroborated reportsof ecological concern (e.g., animal mortality/morbidity,

anatomical or pathological anomalies in aquatic or terres-trial receptors, etc.); and information obtained from thePA/site reconnaissance. In addition, before developmentof an overall site strategy in Phase I, the following projectmanagement information should be obtained:

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. Customers goals and meaning or concept of sitecloseout to focus and define site problem(s).

. Customers budget and schedule constraints.

. Primary and secondary regulatory pro rams underwhich the HTRW project is executed.

2

. The stages or project phases under the above

regulatory programs (i.e., project phase on thecritical path [decision-tree] for actions).

. Stressors (COECs or nonchemical entities), exist-ing or potential exposure pathways, known orsuspected ecological effects from the COECs/nonchemical entities, and endpoints (i.e., value ofresources to be protected) relevant to the cus-tomers objectives or concern.

.OUs, SWMUs, CAMUs, temporary units, areas ofcontamination, etc., and potential exposure units(EUs) or the boundary of ecological concern.

2There are currently unresolved RCRA/CERCLA inte-

gration issues which concern administrative, statutory, and jurisdictional overlap. For example, a Federal facility thatis listed or proposed on the NPL may have interim statusor may be a permitted facility under RCRA. Alterna-tively, it is possible that releases from a RCRA regulatedunit caused the NPL listing. In these cases, the questionsthat follow would be Which statute should be used as the

primary vehicle to require cleanup, if cleanup is needed?and Which agencies (EPA and/or State) should overseethe investigation and cleanup? In certain instances, it ispossible that a Natural Resource Damage Assessment(NRDA) may be required by the customer (DoD, DOE,Department of Commerce) or other relevant naturalresource trustees, such as the U.S. Department of Interior(USDOI) or a State natural resource management agency.By early planning (which may involve negotiations anddocumentation of understanding with the agencies), theapplicable agreements/scope of work and other issues can

be adequately addressed. This process should work wellfor risk assessment and other technical evaluations/data

category requirements in the HTRW project. When aState requires an ecological risk assessment approach orsets cleanup standards substantially different from those ofthe EPA, the data needs to satisfy/supplement or reduceuncertainties in the States approaches should also beconsidered early in this project planning process.

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. Reasonably anticipated future land uses of thsite (which are needed to conceptualize exposures to ecological receptors under future exposure scenarios).

. Anticipated remedies (including removal actioninterim measures, presumptive remedies, aninnovative technologies, if feasible).

. Objectives and scope of all possible executab

phases from the current project phase to sitcloseout.

Based on the above information, the customer and techn

cal planning team members may consult with the relevanexpert ecologist(s) or advisory panel (e.g., BTAG) befofinalizing (or determining) the overall site strategy orthstrategy for the current project phase.

The following activities will be critical for a successfuimplementation of the site strategy:

Identify site Constraints and Dependencies (i.eWork Breakdown Structure [WBS]; producmilestones: level and duration of efforts: availability and timing of funding: technical limitationor requirements; and regulatory deadlines).

Develop potential options, as appropriate, foachieving site closeout (e.g., removal or accelerated cleanup, phasing [in series or parallel], ono further action/monitoring only).

Decide on the executable phase and choose oassemble project decision statements (PDs) specific for the phase, focusing on the critical patand needs for data inputs.

Develop a preliminary ECSM or update an existing ECSM to help meet project objectives andata needs.

Finalize USACE Acquisition Strategy to performwork, issue a preliminary Scope of Work (anoutline for the Statement of Work), and/o

develop a Site Summary/IM Memo, whicincorporates all of the above.

The key output for Phase I is preparation of a Scope oWork Outline and/or TM memorandum which identifiethe customers goals and the concept of site closeout

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time/budget, site and project strategy, preliminary workacquisition strategy, and definition of PDs for data usersto identify data needs (Phase II of the technical project

planning process). With this information, the HTRW

sites PMP can be developed or modified.

D.2.2 Phase II - ldentify Potential Data Needs to

Support Decisions

Phase II of the technical project planning process focuseson identifying the data needs and minimum data quality

requirements to support site decisions identified in thePDs. Phase II activities to identify data needs include:

. Review of the prel iminary ECSM and

identification of project study elements (keydeliverables or work output) to satisfy PDs for thecurrent executable project phase. For the risk

assessor, the following project study elementsmay be appropriate:

- Determine if the site should be eliminated

based on the lack of ecological concern, speci-fically, the lack of valued resources to be pro-tected and/or the lack of food sources tosupport sensitive ecological species.

- Assess baseline ecological risks to determine

the need for remediation.

- Identify or develop potential risk-based PRGs,wildlife concern levels, or benchmark values.

- Evaluate the appropriateness of early actions,interim measures, presumptive remedies, oraccelerated cleanup/removal actions, especiallyfor hot spot areas, to eliminate or mitigate cur-

rent exposure to ecological receptors.

- Evaluate potential early actions or remedies fortheir potential ecological impacts during

response actions or after the remedies havebeen implemented, including the estimated time

for recovery.

- Support RD/RA criteria (e.g., source controlvia construction of a slurry wall and diversion

of runoff away from a nearby stream contain-ing valued game fish species).

- Refine the ECSM, if applicable (i.e., identifyadditional potential ecological receptors orpotential exposure pathways; assess pathway

completeness and the significance of actual orpotentially complete pathways, includingpotential biomagnification across trophiclevels), multiple ECSMs may be needed to

address common sources or locations,transport/migration pathways, and target

receptors.

- Identity applicable inference or linkagebetween measurement and assessment end-

points and/or other sets of endpoints and thestrength of such correlations.

. D&ermine data needs by focusing on data need

categories and the ECSM critically evaluating

their uses or application (based on project back-ground information, requirements of PDs, andproject study elements) to this or subsequentproject phases.

[Chapter 4 of the HTRW Technical ProjectPlanning Guidance provides general site investi-gation data needs checklists and an exampleECSM to illustrate the process for data needsdetermination. A checklist for ERAS, entitled

Super-fund Program Checklist for EcologicalAssessment/Sampling (EPA 1993a), providesbasic information and data needs for a qualita-tive screening evaluation of a COEC at a site.

The risk assessor may also consult with a speci-fic EPA Region or State for similar checklists.]

. Document data needs by identifying the datauser (risk assessor), the intended use, and dataquality appropriate for the use? For the riskassessor, the data needs should be documentedby:

3As discussed in Section D.4, the risk management

decisions associated with the PDs will be supported bythe data collected for the ecological risk assessment or

analysis. The required quality should be appropriate tothe level of acceptable data uncertainties in the risk man-agement decisions. See Chapter 9 for details regarding

risk management decision-making and evaluation of

uncertainties.l Conceptualize data needs to support the relevant

project study elements. For the risk assessor, thedata needs should be used to:

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- Segregating data types and grouping them bypathway and ecosystem, i.e., source area, med-ium, sampling location ordepth, target recep-

tors, etc., based on established site informationand the ECSM.

4

- Specifying an acceptable confidence level in

terms of data variability or ranges of datauncertainty, particularly in the testing of

hypothesis5

4Relevant site information may include records of prior

investigations at or near the site, removal actions, histayof operations, and documentation of the current or futureland use (exposure setting) at the site as determined bythe local land use planning authority or an independentland use expert, etc. Information may be site-specific orgeneral. Published reports concerning the site geology,hydrology, or ecology may include: the Soil ConservationServices (SCS) soil map: the flood insurance rate mapsand flood hazard boundary maps from the Federal Emer-gency Management Agency (FEMA); the USFWS wet-land maps: topographic maps from the U.S. GeologicalSurvey (USGS): and commercially available digitizedflora/fauna data for the Geographic Information System(GIS). Risk assessors should evaluate these data for theirapplicability and useability based on the DQQ approach.

5The observed variability (total error) in any statistical

analysis of a sample population represents bias in sampl-

ing (systematic error) and variability among the indivi-duals in the population and/or the measurement (ability ofthe measurement tool to consistently record the true resultvs random error). The data users specify the limits ofdata uncertainty by informing the data implementor/statistician of acceptable confidence levels to protectagainst false positive or Type I error (rejecting the nullhypothesis and stating the site is contaminated, when thesite is in fact not contaminated) and false negative orType II error (accepting the null hypothesis that the site isnot contaminated, when in fact the null hypothesis is falseand the site is contaminated). Based on acceptable uncer-tainty for protecting the ecological receptors or ecosys-

tems, economics, and other criteria, the data user alsodefines a region of indifference when errors of either typeare considered acceptable. Generally speaking, the Type Ierror may be as low as 80%, and the Type II error 90%.for the RI or RFI project phase. Lower errors may besuggested for other HTRW project phases for considera-tion by the customer or the regulatory agencies.

- Preparing data needs worksheets for epathway which document data types and lotions, and associated QA/QC requireme(including the percent minimum detectarelative difference [MDRD] and accepta

confidence levels). Examples of data neworksheets are presented in the HTRW Te

nical Project Planning Guidance.

D.2.3 Phase III - ldentify Data CollectIon Option

Phase III of the technical project planning process incporates data needs identified from Phase II, and projconstraints or preferences in designing a data acquisitapproach. Phase III generally includes the followactivities:

. Review of Phases I and II information to ens

that the requested data (documented in the dneeds worksheets) submitted by all users consistent with data use and am needed to data gaps for site decision-making.

. Conceptualization of the overall approachsatisfy data requirements, including data for testing of hypotheses. This activity also csiders chemical and physical characteristicsthe site contaminants, particularly those of elogical concern (e.g., chemicals with a high bconcentration factor [BCF]); location of sourcbiological receptors: exposure pathways: meor biota to be sampled, and sampling strategie

. Development ofanalysis activities.

6approaches for sampling a

This activity identifies a

6In designing the abiotic sampling approach, purpos

(judgmental), conventional statistical, or geostatistimethods may be considered to estimate the numbersamples needed and their locations. At this stage, planing for the collection of paired samples for chemianalyses and toxicity tests should be considered. Adtionally, the field screening or laboratory methosampling/data gathering techniques (e.g., composite grab samples), and appropriate QA/QC checks should

evaluated to ensure that they meet quality assuranobjectives for each (executable) stage of the projeThese QA/QC checks may also include performingregression analysis and establishing a correlational coefcient between the field measured data and confirmatiolaboratory analytical data.

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screens for data overlap, defines potential sampl-ing strategies, and recommends the most appropriate sampling and analytical methods (field or

laboratory methods and their detection limits)based on data needs of current and futureexecutable phases. Determining overlaps of dataneeds and combining preliminary options, as

appropriate, should optimize data collectionefforts. The data implementors (statistician,chemist, geologist, biologist, and others) workwith the data users to clarify data needs, and toconceptualize potential sampling approaches.

. Evaluation of cost, schedule, technical feasibilityof the sampling/analytical methods, elimination orminimization of potential confounding factors(e.g., effects of natural selection, seasonal fluc-tuation, etc.), strength of cause-effect relation-ships, and other constraints or benefits associated

with the sampling approaches to arrive at datacollection options. The trade-offs among requisitedata quality and quantity goals to meet the pre-scribed confidence levels or error rates, and theabove factors arc discussed among the data users,data implementors, the expert ecologist(s)/

advisory panel, and PM or TM. The data imple-mentors determine data quantity based on therequired data quality and confidence proposed bythe data user. These activities include:

- Quantify data to be collected. If relevant preli-minary site data are available, the number of

samples or data quantity needed can be esti-mated based on professional judgment and/or

the need to supplement or confirm existingdata. Alternatively, a statistical approach canbe used to identify the required number ofsamples based on the ability to meet the maxi-mum acceptable error rate (level of confidence)

at an assumed or demonstrated data variability(variance) and the minimum detectable relative

difference (MDRD) for the relevant area ofinvestigation, area of ecological concern, or

exposure area.

documentation).7

The objectives of these requirementsare to provide a QA program (precision, accuracy, com-pleteness, representativeness, and comparability) for thechemical data to be collected. For nonchemical types ofdata, e.g., establishing comparability among reference(background) locations or assessing aquifer propertiesused in contaminant transport modeling, a separate set of

7 Duplicates are usually two samples collected at the

same time and location as a measure of homogeneity ofthe medium and the precision in sampling. Replicates or

splits usually originate from one sample that is dividedand sent in the same sample delivery cooler/package tothe same laboratory as a check of laboratory instrumentprecision and accuracy (replicate samples may be split forindependent analysis by different laboratories for com-parability of analytical results). Field blanks are samplesof contaminant-tree medium that are either transferred

from one sample container to another in the field orexposed to field conditions (at the same duration of sam-pling and sample preparation) for use as an indication ofsample contamination during the entire process of field

sampling and sample processing. Trip blanks are needed

for samples collected for volatile organic compound(WC) analysis; they are samples of contaminant-freemedia, which are kept unopened, and which accompanythe site VOC samples as a measure of cross-contamination during collection, shipment, and storage.Rinsate blanks are samples of deionized water that arerun over the sampling equipment, after decontamination ofthe equipment for use as a measure of adequacy of decon-

tamination procedures and potential cross-contamination.Laboratory control samples are samples of the controlmatrix spiked with certified reference materials or ana-

lytes that are representative of the target analytes. Thesesamples are used to verify the precision and bias of the

analytical process, i.e., the results are compared withcontrol limits established for the analytical method to

determine data useability. Other laboratory control proce-dure samples are the matrix spike and the matrix spikeduplicate which are used to document the effect of matrixinterference on the analytical method performance, and

method blanks, which are used to assess laboratory-induced contamination.

- Establish data quality requirements. (For chem-ical data, QA/QC requirements include detec-tion limits, types and numbers of QA/QCsamples [i.e., blanks, duplicates, and controlsamples], frequency of sampling/analysis, and

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quality assurance requirements will be established and can

be done on a case-by-case basis.8

. Document data collection options by identifyingsample types (media), numbers, locations of thesampling stations, and sampling and analytical

methods. A sampling plan may be prepared atthis time to communicate data collection optionsand to provide a rough cost estimate (order ofmagnitude) for each recommended option. It ispreferable that three options be developed for

selection by the customer and other site decision-makers. The project team should also recom-mend the optimum collection program forconsideration by the decision-makers.

The key output for Phase III is an array of data collectionoptions which can be presented to the customer and deci-sion-makers for option selection under Phase IV. The

data collection options presented must be consistent withthe customers goals and concept of site closeout, time/budget, site and project strategy (especially, logical argu-ments and steps to be taken in linking the field measure-ments to the assessment endpoints), PDs, and the projectstudy element(s). The Phase III technical project planningprocess output which is an array of data collection optionsshould be able to:

. Incorporate data needs of the data users anddefine the right data types for development ofDQOs (for the current executable phase, subse-

quent phases, and/or the project as a whole).

. Reduce areas of data collection overlap (e.g.,those requited for preliminary remedial design,human health risk assessment, ERA, and pre-assessment screen of potential NRDA actions [ifapplicable]).

8For example, the customer determines that fate and

transport information is needed to demonstrate a lowenvironmental concern to the aquatic receptors from thepotential migration of groundwater to surface water.After the data implementor has consulted with the

hydrogeologist/modeler (data user) assigned to the HTRWproject, this data implementor may recommend to the TMand the project team that a simple one-dimensional model,although more conservative, may be a better choice than athree-dimensional model, given the time and budget con-straints for a particular project phase.

. Meet budgetary, schedule, and administrativ(FFA, IAG, regulatory compliance) constraints.

. Meet QA/QC requirements and predefineacceptable uncertainty criteria.

Since the data needs are driven by site decisio

requirements, e.g., those related to the ERA, the ECSMprovides the cornerstone for the data collection tabdevelopment. Table D-l outlines the linkage between thECSM and data collection strategy for conducting a basline ERA.

D.2.4 Phase IV - Select Data Collection Optionand Assign DQOs

The Phase IV technical project planning process involvethe selection and documentation of the data collectioprogram in support of an ERA or risk analysis. Suc

documentation will provide a historical knowledge whicjustifies and guides the data review and data use. PhasIV includes the following activities:

. Preparation of a fact sheet or matrix table summarizing the data collection program optionThe fact sheet assigns costs and presents chaacteristics of each data collection option (e.gtypes of sampling and analysis activities, numbers of samples, benefits, uncertainties or limitations, schedules, technical requirements, another constraints). To support the PM or TM i

preparing the fact sheet or the matrix table, th

risk assessor identifies the project study elemenand data needs required to complete the studelement. The risk assessor should documenwhich arc the critical samples or field surveactivities and those data or parameters which arsensitive and, therefore, require a higher level oQA/QC. In addition, the risk assessor providerationale for tradeoffs in quality, quantity, ansampling methods, the anticipated benefits: andata uncertainties for the fact sheet/matrix table.

. Design of a data collection program. This activity includes presenting the data collection pro

gram options to the customer/decision-makerefinement of the customer/decision-makerspreferred option; and final selection of an option

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Table D-1Linkage Between ECSM and Data Collection Strategy

ECSM Linkage Data Needs

The ECSM indicates a potential for exposureof a valued ecological receptor population viaPathway X; within a defined confidence inter-val, the risk is acceptable

Current vs. Future scenario: plausible/not plausible

Likelihood receptor types present:High/Low

COECs

Potential for release/transport

Exposure point concentration estimate

Toxicity assessment

Site related vs. reference or non-site-related sources

Physical and chemical properties of

COEC and source matrices, and thephysical/chemical characteristics of thetransport medium: amenable/notamenable

Considerations for chemical fate andattenuation; uptake and excretion:reasonable/unreasonable

Exposure-response relationship includ-ing assessment methodology isappropriate/not appropriate

In support of the null hypothesis, qualitativedata and/or quantitative data will be pre-sented in the risk assessment

Land Use/Field Reconnaissance or Surveyto identify indigenous or surrogate speciesthat are sensitive to the COECs and arebiologically relevant to the assessment end-points or resources to be protected

History or records of operations/sampling ofmedia to demonstrate comparability of sitecharacteristics at reference locations

Literature values, structure-activity relation-

ship (e.g.EPAs QSAR), bioavailability (acidvolatile sulfide/simultaneously extractedmetal [SEM/AVS] ratio), binding characteris-tics (organic carbon contents), measurementdata of medium flow or speed and COECtransport characteristics

Professional judgment based on physical,chemical and biological properties of COECin media, boundaries or barrier/measurement or predicted (modeled) values

Preponderance or the weight-of-evidenceassessment of uncertainties (a discussion ofthe strength and limitation of the data) forthis tier and phase of data collectionstrategy

. After the data collection program option has been

selected by the decision-makers, the project teamdocuments the selected option by finalizing DQOsand scope of work sections and prepares adetailed cost estimate in support of the decisiondocument.

It should be emphasized that in the process of delibera-tions of data collection and design options, the customer

may decide to eliminate, reduce, or modify the quantity ofdata collected if the customer feels that they are not crit-ical to supporting DQOs and decision-making. For exam-ple, if the customer is very familiar with the site historyand has the operating records/supporting data, he or shemay decide that only compounds X, Y, and Z arc the only

COECs. The sampling effort should therefore focus on

these parameters for subsequent chemical analysis, and

not the full Target Compound List (organics), TargetAnalyte List (TAL), 40 CFR 261 Appendix VIII orAppendix IX chemicals. If tissue samples arc analyzedfor chemical residues, those chemicals with little or nopotential for bioaccumulation (e.g., volatile organiccompounds) should not be included in the list of analytes.A good understanding of the ECSM, the chemical proper-ties and fate, and the regulatory decision-making processin the HTRW program is a key factor which will affect a

productive team effort in this final technical project plann-ing phase.

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D.3 Rob and Responsibilities of a Risk AssessorIn the Data Quality Design Process

The purpose of the HTRW data quality design process isto implement Total Client Satisfaction (TCS) and TotalQuality Leadership (TQL) programs. To do so success-fully, each project team member, under the leadership of

the PM or TM, participates and works cooperatively withother team members to develop data collection programoptions for the customer. Such options cannot be trulydeveloped without a thorough understanding of severalkey elements. This section addresses these key elementsand defines the role and responsibilities of the risk asses-sor regarding site strategy development, identifying PDs,and defining study elements and data needs/quality tosupport risk management decisions. With a clearlydefined role and responsibilities, the risk assessor can bemore focused in serving the customer so that quality datacollection options can be developed.

D.3.1 Site and Project Strategy Development

Under Phase I of the HTRW technical project planningprocess, the technical planning team members work withthe customer to develop the overall site strategy for thecurrent and subsequent executable phases of the project.Further, the site future uses, probable remedies, andoptions to achieve site closeout are identified in thisphase. Therefore, a thorough review of the site historyand background information by the risk assessor will helpfulfill his or her role/responsibility in assisting the strategydevelopment. It is also imperative that the risk assessor

understands the customers goal, concept of site closeout,and communicates his/her thoughts and suggestions toother team members with respect to the following areas:

. The risk assessment requirements for the primaryand secondary regulatory programs. Theserequirements may range from a qualitative deter-mination of whether or not there is a valid ecolo-gical concern, a screening ecological assessment,a baseline ERA, development of PRGs to protectvalued ecological resources, and risk (ecologicaleffects) screening of potential remedial alterna-tives. It should be noted that some risk assess-

ment requirements may be simple and otherscomplex with respect to data needs. The riskassessor should be open and candid about suchrisk assessment or risk analysis requirements,potential assessment approaches and their associ-ated costs and time requirements, and theirstrength and weaknesses as inputs in making sitedecisions.

. Implications of current and future land use arisks. The risk assessor should explain to project team members and the customer h

current and reasonably anticipated future luses (according to customers goal) are factointo assessment of available food sources, hatats, and exposure to site contaminants for s

sitive ecological receptors. Furthermore, direct and indirect effects to be measured shoalso be explained.

. Expert advice or inputs. The risk assessor mpresent arguments and rationale to the expecologist(s)/advisory panel regarding whether assessment endpoints (species or the resourcesbe protected) are appropriate, or the rationale the lack of significant ecological concerns.

. Site background information review and dev

opment of preliminary ECSM(s). The rassessor should review all site background infmation, especially the general site geolohydrology: potential COECs or the nonchemistressors; the physical and chemical propertiesthe stressors; and their release, migration, traport, and fate properties. The objective isconceptualize and refine the preliminary ECSfor use in evaluating potential site closeoptions and guiding selection of data needsPhase II of the technical project planniprocess.

. Short-term and long-term reliability of potenremedies, technologies, or removal actioUnder Phase I, the probable remedies and s

closeout options am identified. The types remedy or technologies employed should thoroughly evaluated by the risk assessor. Tevaluation should focus on the ability and reliility of each alternative to reduce ecotoxiciexposure, and risk, as well as their impact existing habitats and potential recovery of suhabitats after implementation of the proposactions or removal of the nonchemical stressThese technical comments should be based

the ECSMs.

. A sanity check or a check of implementabiand data useability for potential study elemenIt is the responsibility of the risk assessoridentify constraints, benefits, and shortcominof employing certain assessment techniquesdata gathering activities. The objective is

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keep the project team in focus so that ancillaryand research projects without benefit or gain inknowledge for the customers site decision-making are not pursued. Essentially, the riskassessor looks out for the customers interest andcritically assesses if a particular study or datarequisition is warranted.

To summarize, the risk assessor plays the role of a keyproject team member (other key members are responsibil-ity-legal; remedy-design engineer: and compliance special-

ist) and interacts with the customer, PM, TM, and otherteam members to develop the overall site strategy andstrategy for the executable project phases. The risk asses-sor contributes to development of the strategies throughcommunications and dialogues of his or her knowledge inERA requirements for the pertinent regulatory programs,implications of land use or risk, and viability of certain

site closeout options and remedies based on the prelimin-ary ECSMs. Where appropriate, the risk assessor consults

with the expert ecologist(s) or the advisory panel andforges a consensus based on PDs regarding problem iden-tification and formulation, the assessment approach, dataadequacy, cause-effect relationships between stressors, andany observed environmental effects.

D.3.2 PDs and Study Elements

Under Phase II of the HTRW data quality design process,the technical planning team members conceptualize poten-tial data needs based on understanding of the site andproject strategies and decisions to be made under the

applicable regulatory program. In doing so, it is theresponsibility of the risk assessor to understand and artic-ulate the basis for the PDs in terms of the risk assessmentinputs in making the site decision. The risk assessor

identifies the project study element for the current phaseand subsequent phases (if appropriate), andconceptualizes/defines data needs in support of the projectstudy element.

It is also important that the risk assessor and the PM/TMhave a common understanding of the project studyelements and the objectives/utility of the elements tosupport site decisions. Where the study element will be a

cooperative effort among project team members, the ele-ments have to be communicated and understood by allaffected members. For example, a field survey to estab-lish the existence of sensitive environments and valuedresources or the collection of co-located media samplesfor toxicity testing to establish RA objectives can beintegrated into the field investigation activities to identifythe locations of hot spots under an engineering

evaluation/cost analysis (FE/CA) for a potential removalaction. In another example, quarterly groundwater sampl-ing of monitoring wells could be integrated into the same

study element to monitor the community structure orhealth (diversity and abundance) of indicator species such

as benthic macroinvertebrates at the reference locationsand downstream locations of a site for a long-term fieldsurvey. The risk assessor should communicate his or herthoughts and suggestions with respect to the followingareas:

. Study elements to be performed and breakout ofthe elements. The data needs for the elementand its subelements have to be conceptualizedand identified. The risk assessor and other teammembers need to identify the study element orsubelement which may be executed by otherproject team members.

. Provide rationale for data needs in terms ofuseability in satisfying information requirements

for PDs. The risk assessor presents to thePM/TM or the affected project team membersthoughts/ideas and data requirements for execut-ing the study element. The risk assessor mayfind these communications helpful because otherproject team members may be able to identifydata sources or provide alternative approaches tosatisfy data needs.

. Define and document data needs. With anunderstanding of the PDs and rationale for mak-

ing site decisions, the risk assessor has theresponsibility to define data needs and explainhow the data will be used in the study element

in support of site decisions. The risk assessorhas the responsibility to articulate data needsbased on the ECSM, and recommend data qual-ity and confidence levels (applicable for abioticor certain biotic sampling) for a particular infor-mation need on the data needs worksheet.

. Sensitive data or critical samples. Where theinformation or parameter is sensitive as to its

effect on the result to the study element, the risk

assessor should identify these parameters to theproject team. The strength and weakness of therequested data in making inferences, testing of ahypothesis, and providing the weight-of-evidencepresentation with respect to analyzing uncertaintyin the ERA should also be discussed.

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To summarize, the risk assessor plays the role of a keyproject team member and interacts with the customer, PM,

TM, and other team members (as appropriate) to concep-

tualize data needs. The risk assessor has the responsibil-

ity to justify the data needs based on the ECSM and therequirements of the project study element. The dataneeds are defined and documented formally, e.g., using

data needs worksheets.

D.3.3 Data Need/Quality to Support Risk Manage-ment Decisions

Under Phase III and Phase IV of the HTRW technicalproject planning process, the risk assessor and other proj-ect team members identify sampling approaches and datacollection options, refine options, and document theselected option. Negotiations and tradeoffs are anticipated

during these project planning phases because data needs,

quality, and confidence levels may not be completelysatisfied due to budget, schedule, and other constraints.The risk assessors responsibility is to identify and com-municate to the data implementors key data needs andtheir associated desired quality and confidence levelneeded for the project study element. Among others, it is

the responsibility of the risk assessor to stay focused, onlyrequiring those data pertinent to support risk managementdecisions. The risk assessor should communicate histhoughts and suggestions with respect to the followingareas:

. Sampling approaches and analytical requirements.Based on site background information and the

preliminary ECSM, the risk assessor should havealready provided input to the data implementors

and TM on the types (medium-specific), desiredconfidence level, time and location for the sam-ples under Phase II. These requirements should

be based on the ECSM and the physical/chemicalcharacteristics of the COECs (if known) and thesite matrices. If certain COECs are suspected, therisk assessor should review their respective PRGsor benchmark levels, and ensure that the analyti-cal limits are below such levels. This approachapplies to both biotic (e.g., tissue residue analysis)and abiotic samples. In Phase III, the risk asses-

sor communicates and explains data needs andquality assurance requests to the data

implementors.

. Refinement of data collection options. Based onconsideration of project constraints, and

customers preference/input, the proposed datacollection program options may require

.

refinement. This may involve phasing the sitinvestigation or addressing certain hot spot

areas first or limiting the study ares to the EU o

area where the sensitive receptors or valuablresources may be at risk. The risk assessor cacontribute substantially to this refinement effor

by identifying the major exposure pathways and

media of concern.

Field survey/site reconnaissance. The risk assessor should conduct a thorough site reconnaissance and review all site references andbackground information before developing thECSM for use in identifying complete exposure

pathways and the exposure point (medium)This site visit and review also serve to verify thefeasibility/practicality of exercising certain field

data collection options, including locations of thesampling stations and the existence of biota to

be sampled. Data collection options should bepresented to the decision-makers in a clear and

concise manner, e.g., matrix tables supplementedby bulletized discussion of the advantages anddisadvantages, including data uncertainty associ

ated with each option.

l Optimization of the data collection programThe risk assessor works with other project teammembers to prioritize data needs, if necessary

and identify the optimum sampling strategy ocost-effectiveness ideas. As a key member othe project team, the risk assessor should review

past site data and anticipate data needs for futureproject phases to incorporate cost-effective datastrategy into the data collection option(s). (Inaddition to chemical data, incident reports, envi-ronmental impact studies, or fish or wildlifeconsumption advisories published by locacollege/university, natural resources departmentState fish or wildlife conservation districtsshould be reviewed) All data collection optionsmust be able to satisfy the short-term and long-

term goals.

. Assignment of DQOs. Statements concerning

data needs and use and their benefits/limitationsin support of project decisions should be pre-pared for presentation to the customer in theform of a fact sheet for a particular optionAfter the data collection program option isselected, the risk assessment finalizes such state-ments as DQOs for use in the TM package orthe scope of work for work acquisition. An

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essential element in a particular DQO is the deci-sion statement (if-then) regarding data outcomeand options. The DQOs should comply with thecustomers request for information to makeinformed site decisions. For example, if the

assessment endpoint is protection of downstreambivalves or oyster beds during sediment remedia-

tion and the measurement endpoint is a combina-tion of COEC concentration in the boundarysediment and turbidity (expressed as total sus-pended solids), the DQO statement may indicatethe maximum frequency of exceedance of theseparameters during a specified time period, say12 hours. If exceedance occurs, then sedimentdredging is suspended until normal conditions arereestablished.

Playing the role of a key project team member, the riskassessor supports development of viable data collectionprogram options by identifying key data needs and their

required level of confidence and quality. The risk asses-sor has the responsibility to identify the benefits andlimitations of certain data and develop the appropriateDQOs for obtaining such data. The risk assessor also hasa responsibility to work with other project team membersto optimize the data collection program options consistentwith the overall site strategy and the customers goals.

D.4 Data Needs for HTRW Executable ProjectPhases

For scoping of data needs to perform a risk assessment ora risk analysis, the risk assessor and the PM/IM agree on

the project study element for that executable phase. Thestudy is focused on providing the exposure and risk infor-mation to support risk management decision-making for

the PDs.9

Key PDs are statutory or regulatory require-ments which have been identified for each HTRW execut-able project phase in the HTRW Technical ProjectPlanning Guidance. To assist the risk assessor and thosewho oversee performance of the risk assessment/riskanalysis (e.g., PM, TM, and the customer), this sectionprovides a framework for identifying data needs associ-

ated with typical study elements for HTRW executableproject phases under CRRCLA and RCRA (i.e., PA/SIand RFA; RI and RFI; FS and CMS; RD/RA and CMI).Typical data needs are also presented for these projectphases. It should be noted that data needs should not be

9For the purpose of this manual, the project planning

approach used to identify data needs pertains to assessingecological risks posed by the site under the baseline orno-further-action scenario. If removal or remedial actionsare warranted, data will be needed to derive remedialaction objectives (cleanup goals) and to perform screening

or detailed risk-based evaluation of the short-term andlong-term impacts from the potential removal or remedialalternatives. In addition, the risk assessors may berequested to coordinate with other technical planning teammembers to provide inputs and help define data needs forother site evaluations. These requests may be for theplanning of certain response actions, e.g., compliance/cleanup verification levels based on uncertainty of therisk-based remediation action objective; assignment ofresponse action responsibility based on the contribution tosite risk from multiple releases into the environmentalmedium, etc. These data scoping activities are not thefocus of this section, although the general approach forscoping the data needs may be applicable.

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finalized until a review of the existing data has beenconducted to determine data gaps.

The framework for conceptualizing and defining riskassessment data needs consists of the following steps,which are in accordance with the HTRW Technical Proj-ect Planning Guidance:

. Background information review (Step 1) -- Thepurpose of this review is allow the risk assessorto become familiar with site features, hazards(potential COECs or nonchemical stressor[sl to beevaluated), available exposure-response or toxicityinformation, and exposure (potential exposurepathways). The review assists the formulation ofthe problem, evaluation of potential ecologicalconcerns, and the development of the preliminaryECSM.

. Assemble PDs and identify project study elements

specific for each PD (Step 2) - The purpose ofthis step is to identify the decisions to be made sothat the study element or the type of ERA or riskevaluation can be established to support decisions.

. Conceptualize data needs based on the ECSM(Step 3) - This data scoping step requires the riskassessor to identify data needs based on theECSM and the study element required. Existingchemical, nonchemical, or exposure data can beused to characterize exposure to ecologicalreceptors (both spatially and temporally) with or

without the application of fate/transport or othermodels (e.g., food web models).

[As appropriate, the risk assessor may also con-sider data needs in future project phases in orderto refine the ECSM or to facilitate risk evaluationof anticipated removal or remedial actions (ifsuch needs can be more cost-effectively satisfiedby the data collection program in the currentproject phase)].

. Define and group data needs (Step 4) -- Thisscoping activity entails defining the necessary

data (i.e., data gaps) based on earlier steps, andgroups data needs by medium, location (spatialattribute), or time (temporal attribute). Forexample, quarterly sampling of groundwater inter-secting the surface water (seep samples) to esti-mate the exposure point concentration of COECsfor freshwater species to be protected.

. Document data needs (Step 5) - This srequires the risk assessor to document the dneeds by providing the basis or reason for data, how the data are to be used to help masite decisions, and the proposed data quality aconfidence level. The documentation is needso that a record is established to identify

originator of the data request, the applicationuse of the data, and the required quality. Sinenvironmental data could be reported in amanner to tit the users need, the risk assessmay also document and communicate such dcompilation needs in this scoping step.

The following sections present the scoping requiremefor a risk assessment or risk analysis performed for HTRW project phases. For each project phase, the setion identifies the type of background information usuaavailable, the PDs for the project phase, typical projestudy element(s) to be performed, and the data nee

groupings. The discussion of data needs focuses on wsuch data are needed and how they are to be used. Tdiscussions are not intended to be all-encompassing: dneeds depend very much on the project study elemeamount of useable data already in existence, and sispecific conditions.

D.4.1 Exposure Pathway Analysis and RiScreening; PA/SI and RFA

Focusing on risk assessment/analysis data needs, thsection discusses the HTRW data scoping for the prelimnary site evaluation phase in CERCLA and RCRA. Thsite evaluation phase is known: under RCRA as a RFAunder the CERCLA removal (emergency responsauthority as a Removal Assessment; and as a PA/SI undthe CERCLA remedial program. Other HTRW sassessments, although not specifically covered under thestatutes, e.g., the Baseline Environmental Survey inBRAC, are expected to be functionally equivalent. Tproject execution phase for the PA/SI and the RFAgenerally known as a Phase I project execution stage. Fa Phase I project execution stage (i.e., PA/SI or RFA), following technical project planning approach should considered.

D.4.1.1 Background Information Review

Before the data needs are conceptualized, it is recommended that the riskassessor (and the technical planninteam members) carefully review all site background infomation including: TM Memorandum: RCRA Secti

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3019 exposure information for land disposal and certainland treatment units (if applicable): file searches (availableState and/or EPA enforcement or incident reports, fishand wildlife consumption advisories, Prescore of theHRS, SI Worksheets, HRS scoring package, checklists,notes and photos documenting the sites environmentalsetting, etc.): USGS or State geological survey bulletins/references and topographical and National Wetland Inven-tory Maps; State Fish and Wildlife Department informa-tion on fisheries, endangered or threatened species/habitats; EPA databases (Geographic Exposure ModelingSystems [GEMS], PATHSCAN [surface water informa-tion], etc.); aerial photos; and the commercially availableGIS digitized data package.

In addition, the data quality used to produce the SI orExpanded SI reports for proposed placement on the NPL(if applicable) should be reviewed, along with a determi-

nation of whether additional data are needed to supportPDs. The purpose of this review is to obtain a good

understanding of the following issues:

l Regulatory concerns or site problems relating toecological receptors,

10and the significant expo-

sure pathways (source, migration/transport mech-anism, exposure routes, and receptors) to beaddressed.

. Status of the project with respect to an identifi-able decision path leading to site closeout.

. Customers or PMs goals and objectives, plan ofactions, compliance requirements, and budget/time constraints for the current phase and subse-quent phases of the project life cycle (if known).

0.4.1.2 PDs

The following describes the decision step within the criti-

cal path of the HTRW response program relating to theCERCLA and RCRA SA phase:

10In addition to the regulatory actions or concerns, the

risk assessor should also review any draft or final reports

from universities and the local or State natural resourceagencies concerning the site environmental setting and

ecological concerns. The regional USFWS should beconsulted for the existence of endangered or threatenedspecies, including Category 2 and rare species. TheArmys BTAG may be consulted regarding the signifi-

cance of any expressed ecological concerns.

. PA/SI -- Upon completion of a PA/SI, the criti-cal path is likely to be elimination of the sitefrom further action or, if the site score is above28.5 on the I-IRS, for listing on the NPL, orrequire further investigations (under a RI/FS).The no-further-action decision may also include

referral by the USEPA to the State for further

assessment.

. RFA -- Upon completion of a RFA, the criticalpath is similar to that for the PA/SI, i.e., deter-mine whether potential SWMUs can be elimin-ated from further action or should be furtherinvestigated in the RFI phase.

The above broadly defined decision steps in the projectlife cycle indicate that the type of decision to be made forthe SA phase under these regulatory programs is similarto one another (i.e., Should the site be eliminated fromfurther investigation?). The objectives for an SA at thisearly project phase concern the identification of past orcurrent releases, locations, boundaries, assessment of theneed for removal or interim measures, and documentationof all risk reduction actions. Logically, if there is nodocumented history of chemical releases or there arecontainment devices with good structural integrity tointercept the releases, there should be little basis for fur-ther action. On the other hand, if there were documentedreleases, the decision will have to be based on a morecomplicated analysis to ascertain: (I) the environmentalsignificance of the release (based on limited mediumcontamination and an exposure pathway analysis); (2) theneed for removal actions or interim measures to mitigaterisks: and (3) priority of site actions (i.e., hazard rankingof this site relative to other sites) under the HRS or otherprioritization schemes, such as EPAs National CorrectiveAction Prioritization System (NCAPS), guidance on set-

ting priorities for NPL candidate sites (EPA 1992p), orthe DoDs site ranking/prioritization system.

l1High priority is assigned by EPA to sites for which

SIs have been completed and where (1) people are cur-rently exposed to hazardous substances, pollutants, orcontaminants: (2) actual contaminant has been docu-

mented, especially at or above a health-based benchmark:(3) a large potentially affected target population is nearby:(4) contamination to a sensitive environment or fisheryhas been documented: (5) the State has recommended thesite be listed on the NPL pursuant to CERCLA105(a)(8)(B); or (6) the ATSDR has issued a health advi-sory or is planning to.

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On a project management level (not programmatic man-

agement level), items (1) and (2) above are the only rele-vant considerations. Therefore, specific PDs associated

with this executable project phase are:

. Determine if the site, SWMU, AOC, etc., can

be eliminated from further action (i.e., investiga-

tion and/or remediation)..

. Determine if removal action(s)/interim measure(s)are needed to mitigate imminent threat to human

health or to the environment.

D.4.1.3 Project Study Elements

The objectives of the study elements (screening ERAs orrisk screening) are to address the PD on whether or notthe site should be eliminated and whether or not removalactions should be undertaken. Project study elements

should provide evidence in support of or in refute of pastor potential future release, transport, and human health/environmental impacts. Additional support can be pro-vided by a hazard evaluation which considers the chemi-cal identity, concentration, and/or volume of the past orpossible future releases, or the nature, spatial and tem-poral attributes of the nonchemical stressor, and an expo-

sure pathway analysis which includes the identification ofecological receptors of concern or valued resources.

For the SA project execution phase, preliminary quantita-tive chemical data are preferred, although not likely toexist, and qualitative information on the site setting (spe-

cifically, a habitat evaluation for the potential exposure tosensitive ecological species or valued resources) areneeded for all or any one of the following project studyelements:

. Perform a qualitative or semiqualitative screeningrisk evaluation by comparing limited site data

(usually from purposive sampling of visuallycontaminated areas) to benchmark concern levels

such as those identified in the USFWS con-taminant review series by Eisler (1986-1988);NOAAs ER-L and ER-M values for sediments:Ontarios LELs and SELs; chemical-specific

ARARs12

such as State or Federal AWGreat Lakes National Program Offices sment concentrations for PCBs, mercury, p

cides, and other chemicals: backgro

concentrations: inorganic (mineral) nutr

levels, or other appropriate toxicity-based lit

ture values (e.g., AQUIRE database).

Conduct a qualitative exposure assessment, b

on the ECSM, and identify completenesspotential exposure pathways and their signcance or likelihood of release/transport wh

could result in exposure by the target receptThe assessment should also consider: the sizthe site containing the chemical contaminant

relation to the foraging range of the target scies to determine the EU, the physical chemical characteristics of the contamin(including the bioconcentration and biomagncation potential): and media matrices.

. Conduct HRS scoring using PreScore/SI Wosheets to determine the contribution of the enronmental concerns to a HRS score, anddetermine if potential early actions/remo

actions or update of information may signcantly reduce the need for or the scope ofuture CERCLA action.

13

12Other than Federal and State AWQC, which ar

ready, frequently used source of chemical-specific, e

logically based (pseudo-risk-based) ARARs, essentithere are no chemical-specific ARARs for ecological c

cerns. Additionally, cleanup to an ARAR does not necsarily equate with attainment of protective levels.

l3The results of this review and HRS scoring exerc

should be presented to the Customer/PM. If the

assessor can justify a lower HRS score or an insignifi

risk, based on site-specific information, a request

regulatory relief (delisting, modification of permit cotions, etc.) to the agencies may be considered. Tapproach may also be useful to eliminate or priori

SWMUs for a RFI.

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. In limited cases where there are available chemi-cal data, a screening risk assessment may beperformed by employing mean and maximumobserved concentrations, and conservative expo-sure assessment assumptions and models. Thisscreening risk assessment may include the use ofconservative BCFs, BAFs, fractions of soil andvegetation ingested by a herbivore; theequilibrium partitioning (EP) model to predictpore water concentration in wetland sediment(applicable for nonpolar organic compounds): orbox models or limited dilution models to predictthe exposure point concentration for a mixingzone between groundwater and surface water foraquatic organisms.

The above project study elements may discuss current andfuture land use and population characteristics, based onthe discussion of potential exposure pathways. The studyor evaluation may employ the weight-of-evidenceapproach to present potential risk qualitatively and indi-cate uncertainties of the evaluation. The exposure path-way analysis and recommendations should focus on thepotentially complete pathways. The PA prescore mayalso be used to justify whether or not a RI/FS, RFI/CMS,or removal actions/interim measures are likely to beneeded.

D.4.1.4 Conceptualizing and Defining Data Needs

Data needs for the risk assessment should be based on thepreliminary ECSM(s) which should be established in thisphase of the HTBW project planning process, and shouldgenerally be limited to responding to the above-definedPDs. The data needed may be nonchemical in nature,e.g., USGS 7- minute maps, U.S. Chamber of Commerce

Census reports, County Soil Maps, aerial photos, surveys,interviews with local conservationists/naturalists, or othersources of information that can be used to establish theexistence of potential exposure pathways and receptors.The data needed may also be chemical in nature, e.g.,sediment and surface water quality data of potentiallyimpacted wetlands. In other words, the site strategy andPDs developed under Phase I of the HTBW project plan-ning process will be the focus of this data-scoping

activity. The output of this data-scoping (Phase II)activity are the Data Needs Worksheets for this SA (orPhase I) project execution phase or subsequent phases ofproject execution.

D.4.1.5 Establish Preliminary ECSM(s)

To establish the preliminary ECSM the risk assessorshould focus on obtaining information needed to relaterisk associated with the site and assess potential early/immediate response actions. Ihe ECSM, described ingreater detail in Chapter 3, presents all potential exposure

pathways (sources, release mechanisms, transport media,exposure points, exposure routes, and receptors [includingthe relationships among receptor populations in a com-munity and across trophic levels]) and identifies thosepathways which are complete (significant or insignificant)and incomplete. The information should be able to assistthe risk assessor in developing a preliminary ECSM ormultiple ECSMs if there are multiple SWMUs, AOCs,OUs, or CAMUs/TUs or if there are multiple ecologicalreceptors for these groups of sites or SWMUs. TheCAMUs and TUs are most pertinent to the risk assessorfor addressing remediation risk (Phase III project execu-tion phase) from nonchemical entities since they encom-pass the boundary where remedial activities will beconducted. The risk assessor and project team membersuse the ECSM to focus the data collection effort on thosesignificant pathways that may pose potential risks or food-chain effects and to address PD requirements.

Existing data should be reviewed for their quality and usein defining new data acquisition requirements for a pre-liminary or screening risk assessment/risk analysis and fora baseline risk assessment. Any uncertainty in the preli-minary ECSM due to data gaps should also be identifiedin the ECSM. Information needed to develop an ECSMincludes:

. COECs (information concerning the source char-acteristics, ecotoxicity, BCF, BAF, potentiallaboratory or field sample contamination, back-ground and concentrations).

. Potential target media (groundwater, surfacewater, soil/sediment, and air).

. Potential receptors (endangered, threatened,sensitive, and rare species) and their homeranges, and resources of commercial or recrea-

tional value to be protected in the target media.

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. Major exposure routes or pathways of concern(e.g., ingestion of chemically contaminated fish

by raptors).

. Known release or likelihood of a release of a site

chemical from a source, and the manner in which

the release could occur.

. Level of contamination when compared to avail-able ARARs, benchmark values, or PRGs.

. Data useability factors, based on quality assurancecharacteristics, parameters analyzed, validationresults, and the way the data were compiled, thatmay severely restrict their use in the riskassessment (e.g., total organic halogen and soilgas data, combination of deep soil and surfacesoil data sets, low recovery of internal standards,etc.).

. Removal actions or interim corrective measurestaken since site listing or report publication,which may have substantially mitigated exposureand risk.

. Areas or units which have COECs and exposurepathways in common and which pose a commonthreat to human health and the environment.

. Potential secondary sources of contaminants, andtheir release/transport mechanisms.

D.4.1.6 Define Data Types and Preferred DataQuality Requirements

Generally, the data needs for a Phase I project executionphase (or SA phase) are qualitative in nature and do notrequire intrusive field investigations, although field sur-veys (e.g., habitat evaluations) could be highly beneficialto identify the basis for ecological concerns. Wherechemical data are desirable to confirm the presence orabsence of releases, a Phase II HTRW technical projectplanning activity should be employed to define the datatype according to complete or potentially complete expo-sure pathways. The pathways may include soil andgroundwater ingestion, ingestion of food chain products,

and direct contact or co-occurrence of the receptors withthe contaminated media in space and time. The cor-responding chemical data to assess such exposure path-ways include soil, groundwater, food chain products, andairborne contaminant concentrations. The ECSM shouldbe used to organize the corresponding relationships. As adata user, the risk assessor defines the exposure AOC for

a pathway, the data quality needed, and preferred sampling strategy or methods. Examples of data typaccording to medium, for use in assessing potential expsure pathways are:

. Surface soil (ingestion/dermal contact and inhlation of airborne particles).

. Surface water (ingestion/dermal contact).

. Groundwater (generally limited to the mixizone only).

. Contaminated food (ingestion - the food winvestigated can be simple involving one trophlevel, or complex, involving different trophlevels).

The risk assessor then prepares Data Needs Worksheefor each pathway which document the data types, quali

requirements, or needs. For example, the QA/QC requirments could be set as medium or low (QA3 or QA2).

l4EPA has identified three or more levels of QA/QC obje

tives based on the intended data use (EPA 1992d,e): (a) QA1

a screening objective to afford a quick, nonrigorous. and lea

expensive (time/money) preliminary assessment of site conta

ination. It produces data for which there are neither definiti

identification of the chemicals nor definitive quantitation of th

concentration levels, although a calibration or performan

check of method is required along with verification of the dete

tion level. Applicable activities are: samples physical/chemic

properties, extent of contamination relative to concentratiodifferences, delineation of plume in groundwater (head space

soil gas analyses), placement of monitoring well, waste com

patibility, preliminary health and safety check, nonanalyte sp

cific categorization, and preliminary identification/quantitation

chemicals (e.g., pH, ignitability, chlorine presence, etc

(b) QA2 is a verification objective which requires a minimum

10% verification of chemical identity (by an analyte-specif

method) of the field or laboratory results, and a minimum

10% verification of quantitation (accuracy of measured conce

trations). It is intended to give the data users a level of conf

dence for a selected portion of preliminary data. Applicab

activities are: samples physical and chemical properties, exte

and degree of contamination, and verification of plume

groundwater, health and safety check, chemical identificatio

and cleanup. (c) QA3 is similar to QA2 except that 100%

sample results are confirmed for identity, e.g., the use

GC/MS analytical method. That level is most appropriate f

critical samples used to support site decisions. Applicab

activities: comparison with action levels, treatment/disposal, si

removal/remediation, h ea l th r i sk a s se ssm en t , so u r c

identification/delineation, and cleanup verification.

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The level of confidence (maximum error rate) required ofthe sample results should not be set so high, or the detec-tion limits so low, as to be unrealistic and unachievable,considering the potential variability of the sample resultsin a given matrix and the available analytical techniques.However, it should be noted that chemicals which bio-accumulate cannot be effectively eliminated based on low

concentrations or concentrations below nondetection. Inthis instance, analysis of tissue residues may beappropriate in future project phase(s), i.e., in the RI/FS orRFI/CMS project phase. For nonchemical types of data,the quality assurance requirements are established and

done on a case-by-case basis. The risk assessor mayutilize a weight-of-evidence approach to assess the dataneeds and their uncertainties in the SA project phase.The approach generally consists of qualitative data, suchas from a site reconnaissance, to identify if there isstressed vegetation or dominance of tolerant species com-monly found in contaminated sites. Subsequent collectionand analyses of abiotic (media) may be performed insome cases to aid making informed site decisions at this

stage of the HTRW response process. For example, soildiscoloration and vegetation stress at the downgradientlocation (of a hazardous waste storage area) wereobserved where runoff is likely to take place. A smallnumber of selective surface soil samples will be sufficientto make the decision on whether release from the sourcehas occurred and to ascertain if the release is stilllocalized.

D.4.1.7 An Outline or Summarv of theApproaches In the Risk Assessment/Risk Evalua-

t i o n , U n c e r t a i n t y D i s c u s s i o n a n dRecommendations

The approaches or contents of an anticipated riskassessment/risk evaluation summary should be explainedor made known to the decision-makers in the project plan-ning stage in unambiguous terms. This is to avoid poten-tial misuse of the risk assessment results, and can be usedas a means to make sure that the selected data collection

option will meet the users needs.

Due to limitations in data quality and quantity, the riskassessment/risk evaluation performed in a PA/SI, RFA, or

in other site assessments is generally qualitative in nature,e.g., a discussion on the potential exposure pathways andpreliminary ECSM. In the rare instance when a quantita-tive risk assessment is performed (e.g., the ToxicityQuotient Method), the results should be considered pre-liminary and screening in nature since the nature andextent of the contamination is not clearly defined at thistime. In both cases, the uncertainty is considered high

and should be identified as such by the risk assessor in a

qualitative discussion. A quantitative assessment ofuncertainty, using Monte Carlo analysis or other quantita-tive methods to propagate error, is not appropriatebecause this type of risk assessment or analysis is notmeant to be used as a predictive tool. The recommenda-tions derived from the assessment are general, i.e., the

recommendations are expressed as likelihood, proba-ble, and deterministic.

The preferred level of confidence for nonchemical datacould be ranked medium to low. These levels of con-

fidence are justifiable within an SA stage when differentdata inferring the presence or lack of environmental riskare collected, and a weight-of-evidence discussion ofuncertainty is used to explain the evaluation findings andthe recommendation(s). For example, the topography,visual observations, history of spills, runoff pattern, andthe analytical results of purposive sampling would besufficient, as a whole, to support the argument whethercontamination of a medium is likely or unlikely.

If chemical data are available, the level of confidence willdepend on the experience and expertise of the laboratory

to deliver quality data, associated QA/QC control, sam-pling method, sample handling/preservation method, andlast, but not least, variability of the chemical concentra-tions in the medium that was sampled. It is recom-mended that the risk assessor and chemist/data reviewercoordinate their efforts to design a sample collectionprogram which is most likely to produce sample resultswith an acceptable level of confidence. The followingfactors should be considered in this planning activity inorder to reduce uncertainties:

. Use of EPA-approved methods or ASTM proto-cols and the associated QA/QC for conductingchemical analyses.

. Laboratory QA/QC Program - A reputable labo-ratory with established internal and external auditprocedures should be used. For analyses per-formed on a given instrument using a given ana-lytical method, the laboratory should be able toprovide a reasonable estimate of the range of

possible values, given a detectable or estimatedvalue in the data summary report. The labora-

tory should also conduct a preliminary QA/QCcheck before the laboratory results are finalized.

. Level of Quality Assurance - Depending on datause, the level of quality assurance for a PA/SIand RFA can be QA1 (field screening to assist

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identifying sampling locations), QA2 (presence orabsence of contaminants with some confirma-tional analyses), or QA3 (confirmational analyses

of chemical identification and quantification, e.g.,

gas chromatography/mass spectrometry [GC/MSlmethod).

Field and Laboratory QA/QC Samples - If soil orsediment samples are collected and are to be used

in a future phase(s) of work, considerationsshould be given to collecting sufficient volumesfor laboratory QA/QC analytical samples (i.e.,duplicate, matrix spike, and matrix spike duplicatesamples) and for field duplicates; water samplesrequire field duplicates. In addition, samples forthe analyses of volatile and semivolatile organicchemicals should be checked for surrogate recov-

ery. Laboratory blanks should also be analyzedto check for the presence of potential laboratory

contaminants.

Data Variability - Detection of hot spots is gen-

erally not the objective of the sampling programunder a PA/SI or RFA. The number of samplesrequired to represent the level of contaminationwith a predetermined level of confidence will

depend on the uniformity or homogeneity of thecontamination. This information can only beobtained via previous sampling events.

D.4.2 Baseline Ecological Risk Assessment; RIand RFI

This section focuses on HTRW data scoping (data needsand DQOs) for a detailed site investigation phase underCERCLA or RCRA. The detailed site investigation phaseunder RCRA is known as a RFI/CMS and underCERCLA as a RI/FS. Other HTRW site investigationsare expected to be functionally equivalent, for example,for BRAC; for permitting of an onsite hazardous wasteincinerator (RCRA Subtitle C, Subpart 0); for miscel-laneous units (RCRA Subtitle C, Subpart X): or for perti-nent land disposal units (RCRA Subtitle C, Subparts J, K,and L). The site investigation execution phase forCERCLA and RCRA is generally known as a Phase IIexecution project phase.

D.4.2.1 Background lnformation Review

By a Phase II execution project stage, the risk assessorand the project team should have some understanding ofthe site background and descriptions of site characteristicsfrom a review of the preliminary (PA/SI or RFA) data

contained in the Federal Facility Docket or pertinent p

ect files. At certain sites, removal actions, rscreening/exposure pathway analysis, or HRS scoring m

have been performed. This information will be usefulscoping the data needs for a baseline ERA. Before

site strategy for the Phase II execution project phasedeveloped or revised, it is recommended that the proj

team carefully review the TM memorandum (or updates), all site background information, file searchand other relevant information concerning site ecologiresources, habitats, and the receptors of concern.

The data collection approach and quality requiremshould address concerns expressed in the NPL or the Rreport/permit requirements. The site strategy plan shobe revisited and the need for additional data to suppPDs examined.

The background information review should focus on following issues:

. Regulatory concerns or site problems (or newidentified concerns) relating to: receptoCOECs (e.g., ecotoxicity, BAF, BCF), stressof concern, and exposure pathways of concern

. Project status with respect to the decision p

leading to site closeout.

. Customers or PMs goals and objectives, pof actions, compliance requirements, and budgtime constraints for the detailed site investigatiand later project phases.

D.4.2.2 PDs

Broadly defined decision steps relating to detailed sinvestigations in CERCLA and RCRA within the critipath of the HTRW response program are:

. RI -- Upon completion of the RI or the RI/FSthe FS is conducted simultaneously with the Rand signing of the Super-fund Records of Desion (ROD), the critical decision step will either the elimination of all or certain OUAOCs from the next phase of the project, (i.

no RD/RA needed based on the baseline ERand compliance with ARARs) or a RD/RAneeded (for portions of the site or for the entsite) which proposes selected remedies to migate risks and comply with ARARs. The desion path also includes considerations fremoval actions/interim actions and pub

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notice/participation on the proposed remedies orno action alternative.

RFI -- Upon completion of the RFI, the criticaldecision step is likely to be either that (1) furtherstudy is required (i.e., corrective measure study)to define baseline risk and to propose remedial

alternatives or (2) no further remedial action isrequired (i.e., compliance is achieved with respectto permit conditions or RCRA enforcementactions) based on comparison with proposedaction levels, ARARs, or benchmark values. Ifthe baseline risk assessment indicates unaccept-able risks, corrective measures (selected remedialalternatives) will need to be implemented. Thedecision path also includes considerations forremoval actions/interim corrective measures.

There are many objectives for a RFI and RI. For exam-ple, a Phase II project executable stage identifies COECs,investigates the amount of release and the nature/extent ofmedia contamination, evaluates the fate and transportproperties of CORCs and affected media, assesses base-line risks, determines the opportunities for removalactions or interim corrective measures/early actions, asses-ses and recommends remedial alternatives to mitigaterisks, and documents investigation and response actions.Generally, if there is no appreciable evidence of release orif the baseline ecological risk is acceptable (determinedeither through a baseline risk assessment or a comparisonwith ecologically concern levels or benchmark levels),there should be little basis for a FS, CMS, RD/RA, or a

CMI. If contamination is found at the site (onsite, offsite,or at multiple locations) and ecological receptors couldco-occur with this contamination spatially or temporally(e.g., during the early life cycle in the species naturalhistory), a site-specific baseline risk assessment will beneeded to ascertain if:

. Further investigation (e.g., to address hot spots) iswarranted with or without removal actions.

. Immediate or emergency response actions tomitigate short-term risks are needed.

. Remedial alternatives/corrective measures shouldbe implemented to mitigate site risks.

Therefore, specific project decisions (PDs) associated witha Phase II executable project phase are:

. Determine if the site, SWMU, AOC, and, moreappropriately, the EU, pose significant risk to the

environment to warrant remediation or correctivemeasure.

. Determine if removal actions/interim correctivemeasures are needed to mitigate imminent threatto the environment.

D.4.2.3 Project Study Elements

The project study elements for a Phase II project execu-tion stage are concerned with defining the site nature andextent of contamination (including establishment of back-ground or reference chemical concentrations to meet PDrequirements): establishing an understanding of the fateand transport mechanisms of chemicals based on thefindings of a site characterization element; and conductinga baseline ERA (based on the site characterization, fate/transport findings, site features, hazard [ecotoxicity orstress] and exposure information). For a Phase II projectexecution phase, data may be needed for all or any one ofthe following project study elements (including the base-line ERA) to respond to PDs of whether or not there is aneed to undertake removal actions or remedial action/corrective measures. If a FS or CMS is to be performedafter the RI or RFI, the project study elements must alsosupport a decision of whether to go forward with the FSor CMS based on significant adverse impact (or risk) tothe ecological receptors of concern or to valued resources.Potential study elements for a Phase II project executionphase are identified as follows:

. Evaluate the basis or need for emergency

response or nonemergency (nontime critical)removal actions based on frequency, duration,and intensity of hazard, and the magnitude ofresponse.

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[USACE] Risk Assessment Handbook, Volume II - Z - A-d

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