Office of Solid Waste and Emergency EPA 542-F-05-008 

Response (5102G) September 2005 

 www.brownfieldstsc.org

Use of Dynamic Work Strategies Under a Triad Approach for Site 

Assessment and Cleanup – Technology Bulletin 

 September 2005 

Since its inception in 1995, the U.S. Environmental 

Protection Agency’s (EPA) Brownfields Initiative and other 

revitalization efforts have grown into major national 

programs that have changed the way contaminated 

property is perceived, addressed, and managed in the 

United States. In addition, over time, there has been a 

shift within EPA and other environmental organizations in 

the way that hazardous waste sites are cleaned up. 

Project managers, regulators, technology providers, and 

other stakeholders are increasingly recognizing the value 

of implementing a more dynamic approach to site cleanup 

that is flexible and focuses on real-time decision-making in 

the field to reduce costs, improve decision certainty, and 

expedite site closeout. As shown in Figure 1, the Triad 

approach uses (1) systematic project planning, 

(2) dynamic work strategies (DWS), and (3) real-time 

measurement technologies to reduce decision uncertainty 

and increase project efficiency. 

The EPA Brownfields and Land Revitalization Technology 

Support Center (BTSC) is preparing a series of technical 

bulletins to provide additional information about how to 

implement specific aspects of the Triad approach. This 

bulletin focuses on planning and implementation of DWSs, 

presenting: 

1. Answers to frequently asked questions on 

implementing a DWS 

2. Summaries of the application of DWS at two 

redevelopment sites, including: 

• Former Cos Cob Power Plant, Greenwich, CT 

• Assunpink Creek Greenway, Trenton, NJ 

3. Sources of additional information for communities and 

project teams desiring to implement a DWS and the 

Triad approach 

Additional information on the BTSC is presented in the 

box to the right. 

IMPLEMENTING A DYNAMIC WORK STRATEGY 

What is a dynamic work strategy? 

A DWS allows data collection and cleanup activities to be 

performed in real time as parts of an integrated field effort. 

The actual number of field mobilizations depends on the 

complexity and constraints of a project but is always fewer 

than would be required under a static work plan design. 

Under the Triad approach, a DWS is specifically 

structured to resolve uncertainties about the presence and 

extent of contamination, exposure pathways, and 

selection of the right cleanup strategy. Real-time project 

execution allows projects to reach a successful conclusion 

faster, with less expense, and with greater certainty. 

Depending on the nature of a project and the judgment of 

the project team, a DWS can be planned and written to 

deal only with the data collection phase or to encompass 

both data collection and remedy implementation. DWSs 

that incorporate both sets of activities require more 

comprehensive planning and are more technically 

demanding, but they greatly improve the efficiency of field 

work because collection of additional data, refinement of 

the data collection design, selection of the remedy (from a 

pre-planned short list of options), and remedy 

implementation all can be performed while the project 

team is still on site. 

About the Brownfields and Land Revitalization 

Technology Support Center (BTSC) 

EPA established the BTSC (see www.brownfieldstsc.org) 

to ensure that brownfields and other land revitalization 

decision-makers are aware of the full range of 

technologies available for conducting site assessments 

and cleanups, and can make informed decisions about 

their sites. The center can assist federal, state, local, and 

tribal officials plan for use of the Triad approach at a 

specific brownfields or land revitalization site. This type of 

support includes evaluating available planning documents 

to determine how to incorporate elements of the Triad, 

such as better use of field analytical techniques or use of 

decision support tools. Localities can submit requests for 

assistance through their EPA Regional Brownfields 

Coordinators, online, or by calling 1-877-838-7220 toll 

free. For more information about the BTSC, contact Dan 

Powell at (703) 603-7196 or powell.dan@epa.gov. 

Figure 1: 

Systematic 

Project 

Planning

Dynamic Work 

Strategies

Real-Time Measurement Technologies

The Triad Approach

Systematic 

Project 

Planning

Dynamic Work 

Strategies

Real-Time Measurement Technologies

The Triad Approach
Use of Dynamic Work Strategies Under a Triad Approach 

2

Even if a DWS involves data collection only, the project’s 

bottom line will benefit from rapid generation of higher 

data densities in areas of the site where the information is 

needed most. 

Important features of a DWS include: 

• A flexible and adaptable approach to sampling 

and data collection, that can continually be 

adjusted and refined in the field as new data are 

generated and data gaps are identified. 

• An analytical quality control (QC) program that is 

also adaptive in nature, collecting QC samples that 

focus on the principal sources of uncertainty and 

incorporating real-time data QC review. 

• A clear decision logic applied in the field to guide 

the DWS, established and approved prior to the field 

program by the project stakeholders. The decision 

logic, along with the lines of responsibility, 

authority, and communication for decisionmaking, is based on the site-specific exposure 

pathways of concern, reuse objectives, and data 

collection technologies. It is documented in project 

planning documents (see the discussion below). 

Figure 2 shows a proposed example decision flow 

diagram, prepared with the assistance of the BTSC, for a 

targeted brownfields assessment (TBA) planned for a 

chemical site with concerns about volatile compounds. 

This flow diagram presents a synopsis of the entire 

technical approach for the investigation of the site, 

encompassing multiple environmental media and a range 

of potential chemical classes of concern. The diagram 

allows the stakeholders to reach major remedial and reuse 

decisions concerning the site in a single mobilization that 

employs a DWS. 

The results of data collection using a DWS are used to 

continually refine the conceptual site model (CSM, the 

decision-makers’ “picture” of site contamination) and the 

sampling and analytical approach in real time; in cases 

where there are significant unexpected results, revisions 

to the decision logic itself or to the overall project 

objectives may be needed. The field work continues until 

all decision objectives established for the project are 

attained with an acceptable level of certainty. The level of 

certainty is predetermined by the project decision-makers 

during systematic planning efforts. The soundness of 

project decisions and attainment of the project objectives 

should be verified before demobilization by performing 

quality assurance (QA) activities such as a data quality 

assessment (DQA) (EPA 2000b). 

Fundamental to the success of a DWS 

is the ability to manage, review, and 

report data from the field to support 

fast decision-making. An increasing 

number of tools are available to assist 

project teams with efficient management of field data. For 

example, the Scribe and Scriblets database programs 

available from the EPA Environmental Response Team 

(see www.ert.org) are designed for data entry and upload 

in the field from laptops and personal digital assistants 

(PDAs). The uploaded database can be ported to 

statistical packages and decision support tools (DST, such 

as the FIELDS and SADA software packages); see 

http://www.frtr.gov/decision support for further information 

about various software tools used for decisionmaking and data presentation. DSTs are 

discussed in a separate BTSC bulletin. 

How is a dynamic work strategy incorporated into 

project planning documents? 

A DWS does not require a separate project document. 

Rather, a DWS is incorporated into the plans typically 

prepared for a project, including work management plans 

(WMP), sampling and analysis plans (SAP), and QAPPs, 

and is thus captured along with the other components of 

the Triad approach, including systematic project planning 

and real-time measurement technologies. The difference 

is that, unlike work plans developed under traditional 

approaches, a DWS does not attempt to identify all 

sample types, locations, and quantities at the outset of an 

investigation. Within the planning documents, the DWS 

may identify general sampling approaches (for example, 

statistical or judgmental) or initial sampling locations, but it 

leaves the details of the data collection approach to be 

developed and adapted in the field. This adaptive strategy 

applies not only to the sampling approach but also to the 

analytical methods, the QA/QC program, the 

communication strategy, and other project elements, 

which are continually revised and adjusted as data are 

generated. Key items to be captured in the project 

planning documents are listed below. 

• The systematic planning process – the project 

stakeholders, the project team, site reuse objectives, 

types of decisions to be made, the preliminary CSM, 

and the amounts and types of decision uncertainty 

that can be tolerated 

• Decision logic and decision trees – decision rules 

written as specifically as possible to guide the field 

program 
Potent

or h

ide

Continue pushing soil gas and soil sampling probes until nondetect or a depth of 20 feetbelow ground surface is reached using 5 foot sampling intervals.Step outs outside the siteboundaries using a grid approachmay also be needed. Perform direct 

soil sampling tcontamination When contamicollect soil samintervals down Analyze samplindicated on T

Yes

No

Q

Perform soil gas sampling forapprox. 4 days, using a combination of a grid and judgmental approach. Analyze samples for VSC, H2S, amines 

using on-site mobile laboratory

Continue pushing soil gas and soil sampling probes until nondetect or a depth of 20 feetbelow ground surface is reachedusing 5 foot sampling intervals.Step outs outside the siteboundaries using a grid approachmay also be needed.

Review analytical data frommobile laboratory and off-siteanalyses

Identify alternate methods orperform method development toimprove data quality for futureevents

Assess risks associated withchemicals of concern at the siteDesign and cost a strategy forsite restoration and reuse

Is there a threat

to deeper soil or

groundwater?

Design and implement drillingprogram to assess deepsubsurface soil and groundwater

Select active soil gas sampling conditions based on preliminarytesting

Potential sources

or hot-spots

identified?

Perform direct push drilling andsoil sampling to 5 feet bgs wherecontamination is not evidenced.When contamination is presentcollect soil samples at 5 footintervals down to 20 feet bgs. Analyze samples for analytesindicated onTable 2

Q

Select active soil gas sampling conditions based on preliminarytesting

Potential sources

or hot-spots

identified?

Perform direct push drilling andsoil sampling to 5 feet bgs wherecontamination is not evidenced.When contamination is presentcollect soil samples at 5 footintervals down to 20 feet bgs. Analyze samples for analytesindicated onTable 2

Use of Dynamic Work 

Figure 2: Proposed Example Decision Tree Incorporating Dynamic Work Strategy 

Yes 

No 

Yes 

Yes 

No Abbreviations: 

Bgs Below ground surface H2S Hydrogen sulfide 

VOCs Volatile organic compounds 

VSCs Volatile sulfur compounds 

Have chemicals 

of concern been 

reliably identified? 

Yes

Potent

or h

ide

Continue pushing soil gas and soil sampling probes until nondetect or a depth of 20 feet below ground surface is reached using 5 foot sampling intervals. Step outs outside the site boundaries using a grid approach may also be needed. Perform direct 

soil sampling tcontamination When contamicollect soil samintervals down Analyze samplindicated on T

Yes 

No 

No

Yes

Yes

No Abbreviations:

Bgs Below ground surfaceH2S Hydrogen sulfide

VOCs Volatile organic compounds

VSCs Volatile sulfur compounds

Perform soil gas sampling for approx. 4 days, using a combination of a grid and judgmental approach. Analyze samples for VSC, H2S, amines 

using on-site mobile laboratory 

Continue pushing soil gas and soil sampling probes until nondetect or a depth of 20 feet below ground surface is reached using 5 foot sampling intervals. Step outs outside the site boundaries using a grid approach may also be needed. 

Review analytical data from mobile laboratory and off-site analyses 

Have chemicals 

of concern been

reliably identified?

Identify alternate methods or perform method development to improve data quality for future events 

Assess risks associated with chemicals of concern at the site Design and cost a strategy for site restoration and reuse 

Is there a threat 

to deeper soil or 

groundwater? 

Design and implement drilling program to assess deep subsurface soil and groundwater 

Select active soil gas sampling conditions based on preliminary testing 

Potential sources 

or hot-spots 

identified? 

Perform direct push drilling and soil sampling to 5 feet bgs where contamination is not evidenced. When contamination is present collect soil samples at 5 foot intervals down to 20 feet bgs. Analyze samples for analytes indicated on Table 2 

3 
Use of Dynamic Work Strategies Under a Triad Approach 

• Standard operating procedures (SOP) – clear 

methods for sampling and analysis that are not “off 

the shelf” but have been evaluated and refined as 

necessary to meet the specific project data and 

decision needs (for example, through a 

demonstration of method applicability) 

• Data assessment and QA/QC – the tools to be used 

for data assessment (for example, statistical routines 

and models) as well as the means by which data 

quality will be assessed and uncertainty will be 

managed in real time through QC checks and QA 

oversight activities 

• Data management and documentation – the 

pathways, tools, and formats by which data will 

quickly and securely flow from the analytical 

instruments to the decision-makers as well as the 

documentation trail that will support real-time 

decisions while the investigation team is in the field 

• Communication strategy – roles and responsibilities, 

authority, lines of communication and information 

flow, communication tools, and the frequency for 

decision-making and decision approval 

• Scheduling and logistical considerations – optimal 

investigation time frames as well as how different field 

activities, staff, and equipment will be coordinated for 

maximum efficiency 

• Contingencies – major uncertainties associated with 

the scope or direction of a DWS that may require 

identification of additional or alternate methods in 

planning documents (so that the methods are ready 

for rapid implementation or expansion as the field 

program progresses) 

What types of strategies are used to manage 

uncertainty in a dynamic work strategy? 

Sound defense of project decisions requires effective 

management of uncertainty. Under a Triad approach, it is 

important that decision uncertainty be managed during the 

investigation. Under traditional data collection strategies, 

data uncertainty is a major source of decision uncertainty. 

Data uncertainty is caused by many different factors. A 

very common and important cause of data uncertainty is 

that the number of samples collected is found to be 

insufficient for decision-makers to be sure that all 

contamination has been located. Uncertainty caused by 

insufficient sampling density also greatly impacts 

estimates of remedial costs because not enough 

information is available to know what the most effective 

cleanup option might be. Data uncertainty can also be 

caused by improper selection or use of analytical 

methods; in this case, the decision-makers do not have 

the right kinds of data to support risk and remedy 

decisions. Triad’s systematic planning process addresses 

all these kinds of issues and builds their resolution into the 

project planning documents before field work begins. 

Geoscientists and chemists who are familiar with field 

sampling and analytical technologies should be involved in 

project planning and in writing the planning documents. 

While field work is being done, these personnel should 

monitor data generation and the QC results to make sure 

that the data will be usable to support project decisionmaking within the agreed-upon tolerances for uncertainty. 

These tolerances may be expressed qualitatively using 

professional judgment or quantitatively using statistics. 

Presented below is a partial list of uncertainty 

management techniques that have been used 

successfully to improve data quality in recent DWS 

projects: 

• “Front-loaded” QC sampling – collecting a higher 

proportion of QC samples (for replicate 

measurements and spikes) at the beginning of a field 

program to allow a confident assessment of method 

performance. Once the baseline performance is 

established, the QC sampling frequency can be 

reduced. 

• Focused QC checks – altering the nature or 

frequency of QC checks to focus on managing 

relevant uncertainty because of changes in field 

conditions or instrument performance. Examples 

include increasing the QC sampling frequency for a 

complex or variable matrix that is encountered during 

the investigation, adding a new target compound to 

calibrations, adjusting the range of the calibration 

curve, and increasing or decreasing QC spike 

mixtures used as analytical controls. 

• Use of collaborative methods – using results of 

different methods to corroborate or confirm the results 

of a specific field-based method. Many programs 

have historically used off-site laboratories (for 

example, laboratories employing SW-846 methods) to 

corroborate results of field methods such as 

immunoassay test kits. This approach can foster a 

powerful collaborative data set that can be used to 

manage multiple sources of uncertainty; the high data 

density afforded by the test kits can be used to 

manage sampling uncertainty (heterogeneity), while 

the laboratory methods can be used to manage 

analytical uncertainty. Collaborative data sets are 

particularly important when samples have chemical 

4 
Use of Dynamic Work Strategies Under a Triad Approach 

concentrations near an action level and the analytical 

precision of the field method is insufficient to establish 

compliance with or exceedance of the threshold. 

Well-homogenized split samples can be submitted for 

more rigorous analysis to obtain data that are precise 

enough to allow management of this type of decision 

uncertainty. 

• Anticipation of contingencies for measurement 

methods – being capable of performing minor method 

modifications in the field as necessary. Examples 

include adjusting sample volumes, extraction 

parameters, or calibration procedures and adding 

new method steps (such as sample cleanup steps). 

Using a DWS for data collection requires good 

coordination among multiple members of a project team 

(field crews, project decision-makers, and other 

stakeholders) and may challenge the team members in 

terms of their roles and level of effort needed. As such, 

effective implementation of a DWS requires a cooperative 

relationship among all the members of the project team 

and a firm commitment to real-time decision-making. 

Case studies and brief project profiles describing DWSs in 

the context of Triad projects for a broad range of sites are 

available at www.triadcentral.org. Two examples are 

summarized below. 

EXAM P LES O F HO W A DYNAMIC WO RK STRATEG Y 

IS IM PLEM ENTED FO R REDEVELO P M E NT 

INVESTIG ATIO NS 

Example#1: Cos Cob Power Plant, Greenwich, 

Connecticut 

The Cos Cob Power Plant site is located in the 

southeastern corner of Connecticut on Long Island Sound. 

The Town of Greenwich plans to reuse the site and 

received a TBA grant to assess potential reuse options. 

EPA Region 1 requested assistance from the BTSC in 

maximizing the efficiency of the TBA by applying the Triad 

approach. 

Site Facts 

9 l

9

lds) 

9 ith 

9 f

i

l

Former coal-fired power p ant that operated from 

1907 to the 1960s 

Planned for recreational reuse (walking trails and 

playing fie

Principal threat is direct contact w

contaminated surface soil 

Contaminants o concern (COC) included 

petroleum-related substances, polychlorinated 

biphenyls (PCB), and arsenic associated w th fly 

ash (used as fil ) and transformers 

Work Plan Development 

With the BTSC’s assistance, EPA Region 1 revised the 

limited, traditional sampling approach originally proposed 

for the site and developed a DWS. The DWS called for 

random grid sampling and field-based measurement 

technologies to expand the extent and density of 

investigation across the site for total petroleum 

hydrocarbons (TPH), polycyclic aromatic hydrocarbons 

(PAH), and PCBs. The goal was to delineate the COCs in 

soils at the site in a single mobilization rather than use the 

phased approach originally envisioned for the TBA. 

During the development of the TBA work plan that 

documented the DWS, ultraviolet fluorescence (UVF) test 

kits were verified as useful field-based methods for TPH 

and PAH measurement through a method applicability 

study. This study also allowed the development of 

correlation curves between the field test kits and 

laboratory analytical methods, allowing estimation of fieldbased action levels to be used with the test kits to classify 

sampling locations in three ways: “clean,” “dirty,” or 

“uncertain” (requiring collaborative off-site laboratory 

data). The field-based criteria were further developed into 

decision trees and incorporated into the work plan to 

support decision-making in the field. In addition to the 

UVF test kits, the TBA work plan specified field-based gas 

chromatography (GC) analysis for PCBs by EPA Region 

1’s mobile laboratory. 

Implementation of Dynamic Work Strategy 

The field effort at the Cos Cob Power Plant site was 

completed in 1 week in February 2003. Direct-push 

methods were used to collect soil samples down to 4 feet 

below ground surface (bgs) within a 70- by 70-foot 

sampling grid extending across the site (see Figure 3). 

The sampling location within each grid element was 

selected randomly unless a specific area of potential 

contamination was identified, in which case a judgmental 

(biased) sample was collected. Initially, only samples 

5 
Use of Dynamic Work Strategies Under a Triad Approach 

collected from the top two 1-foot intervals at each location 

were analyzed in the field, and a percentage of the 

samples collected were sent off site for collaborative 

analyses. Field analyses were performed for TPH and 

PAH at all locations using the UVF test kits, whereas PCB 

analyses were performed only in grid elements where 

PCB releases were believed to be possible based on 

historical information. Selection of samples for off-site 

TPH and PAH analysis was biased toward samples with 

test kit concentrations in the “uncertain” range (that is, the 

concentration range where samples could not be called 

“clean” or “dirty” with an acceptable level of certainty 

based on the method applicability study). Selection of 

samples in this manner allowed for refinement of field-tolaboratory correlations and of the field-based decision 

criteria as the investigation progressed. 

Project Results 

The dynamic field program at the Cos Cob Power Plant 

site rapidly clarified the principal reuse questions and 

remedial options for the project team and the Town of 

Greenwich. Field-based technologies were used to 

increase site coverage (that is, data density) and to limit 

decision uncertainty. Key ranges of concentrations and 

safety factors were identified and refined to guide data 

interpretation and decision-making in the field using realtime methods, and these ranges also became the focus of 

collaborative data collection using off-site methods to 

increase decision confidence. Although concentrations of 

some COCs (TPH, PAHs, and arsenic) exceeded 

Connecticut residential criteria at a number of site 

locations, these concentrations were nevertheless 

relatively low given the reuse plan for the site. These 

findings suggested that limited remedial action combined 

with modification of the reuse alternatives or the cleanup 

criteria could facilitate site reuse. The Town intends to 

use the TBA data to prepare a remedial action plan, which 

may involve limited excavation of some areas along with 

capping and land use restrictions (to prevent excavation) 

in other areas. The Town is planning a recreational reuse 

for the site as a waterfront park. Remedial actions (e.g., 

caps) will be incorporated into the park design. 

Figure 3: Sampling Locations for Dynamic Work Strategy – Cos Cob Power Plant Targeted Brownfields Assessment 

Source: EPA. 2004. Case Study of the Triad Approach: Expedited Characterization of Petroleum Constituents and PCBs 

Using Test Kits and a Mobile Chromatography Laboratory at the Former Cos Cob Power Plant Site. July. 

6 
Use of Dynamic Work Strategies Under a Triad Approach 

The DWS applied at the Cos Cob Power Plant site 

established the principal contamination issues and reuse 

options for the site without the need for additional 

mobilizations. The cost savings realized by the DWS as 

compared with use of a more traditional, phased 

investigative approach were estimated at between 20 and 

40 percent. Time was also saved in that the project was 

completed in a single mobilization and TBA funding cycle. 

Example#2: Assunpink Creek, Trenton, 

New Jersey 

The City of Trenton has been 

aggressively implementing the Triad 

approach since 2001 as part of its 

program to redevelop a large number of 

abandoned industrial sites. DWSs in 

particular were used to characterize 

contamination at approximately 40 acres 

spread out over 5 parcels of land along the 

Assunpink Creek which are targeted for 

recreational reuse. 

Site Facts 

9 ire 

i

shops 

9 l

9

need to di

specif l

Sites of interest included a former w

manufacturer, a railroad fre ght yard, and repair 

COCs inc uded heavy metals, petroleum 

hydrocarbons, PAHs, and PCBs 

The area had been industrialized since the late 

1800s; previous investigations had revealed a 

fferentiate between the impacts on 

ic sites from general fill materia s, because 

these are treated differently under NJ State law 

Work Plan Development 

Through a systematic planning process involving multiple 

stakeholder meetings, a preliminary CSM was developed, 

and an investigative approach was formulated that 

involved two phases. Phase I was designed to address 

the nature and distribution of the historical fill materials 

and identify specific COCs and areas of concern (AOC) 

for further investigation. Phase I also included a method 

applicability study to demonstrate that the field-based 

methods proposed for use in the study area could produce 

effective data for decision-making. 

Based on the Phase I findings, a dynamic work plan was 

developed for Phase II investigation of AOCs at the former 

wire manufacturer (Crescent Wire) site and the railroad 

freight yard. The work plan included multiple features 

designed to promote real-time decision-making in the field, 

such as: 

• Technical approach sections that presented the 

preliminary CSM for each AOC along with decision 

rules, cleanup levels, and “possible scenarios” 

encountered in the field that could drive further data 

collection and completion of the CSM 

• Project-specific field sampling and analytical 

procedures established during the method 

applicability study in Phase I, including geoprobe soil 

and groundwater sampling with continuous soil 

conductivity measurement and use of field gas 

chromatography/mass spectrometry (GC/MS) for 

PAHs, immunoassay (IA) test kits for PCBs and TPH, 

and x-ray fluorescence (XRF) for metals 

• A data management and communication section 

describing field documentation requirements and 

protocols for communication between the field team, 

the project management team, and off-site 

stakeholders (the City of Trenton and the New Jersey 

Department of Environmental Protection [NJDEP]) 

• A schedule and logistics section describing the 

preferred time frame for mobilization and the 

anticipated duration of the field program 

An example of the decision logic presented in the work 

plan for the Crescent Wire site is shown in Figure 4. 

Implementation of Dynamic Work Strategy 

The DWS was incorporated into a request for proposals 

(RFP) to hire a technical support contractor for the field 

investigation. The project team found that the DWS and 

the Phase I results presented in the RFP greatly improved 

the quality and creativity of the bid packages and 

produced focused yet flexible pricing schemes. The 

contractor selected also assisted in finalizing the DWS in 

the work plan. When the field investigation began, the 

DWS relied on a three-tiered analytical program of 

collaborative methods to achieve high sample densities 

while still attaining low detection limits for specific COCs at 

decision points. The three tiers of methods included fieldbased, semiquantitative methods with high sample 

throughput for classes of COCs (IA methods); field-based, 

noncertified methods with higher specificity (mobile 

laboratory GC/MS and XRF); and off-site, certified 

methods for specific COCs (SW-846 methods). Sample 

results produced using these methods were integrated on 

a continual basis to support daily field decisions. 

7 
Use of Dynamic Work Strategies Under a Triad Approach 

Figure 4: Excerpt from Dynamic Work Plan for PCB/Oil-Impacted Area of Crescent Wire Site 

Assunpink Creek Greenways Project, Trenton, New Jersey 

Field 

Path Objective(s) Sampling Requirements COC Analytical Delineation Criteria Decision Rule 

Method 

Delineate the lateral and vertical PCBs Immunoassay 

test kits 

NJDEP Soil Cleanup 

Criteria (SCC) 

From location where impacts were previously 

observed, step out at 25-foot intervals and down at 

5-foot intervals until concentrations are below the 

delineation criteria. Once concentrations are below 

delineation criteria, step in once 10 feet. If a potential 

on-site source is identified, follow Path 3. 

1 extent of PCB/Oil impacts in onsite saturated soils, identify a 

Saturated soils around the 

known impacted area. TPH Immunoassay 

test kits 1,000 mg/kg 

possible onsite source area(s). Metals XRF No Criteria 

2 

Delineate the lateral and vertical 

extent of PCB/Oil impacts in onsite groundwater. 

Groundwater around the 

known impacted area. PCBs Immunoassay 

test kits 

Class IIA 

Groundwater Quality 

Standards 

From center of worst case soil impacts determined 

from Path 1, step out at 25-foot intervals and down at 

5- to 10-foot intervals until concentrations are below 

delineation criteria. 

Delineate PCB/Oil impacts in Unsaturated soils overlying PCBs Immunoassay 

test kits SCC From the potential on-site source area, step out at 

25-foot intervals and down at 5-foot intervals until 

concentrations are below delineation criteria. Once 

concentrations are below delineation criteria, step in 

once 10 feet. 

3 unsaturated soils, a potential onsite source area(s). 

most impacted saturated 

soils and/or groundwater. TPH Immunoassay 

test kits 10,000 mg/kg 

Metals XRF No Criteria 

Source: Langan Engineering and S2C2, Inc. 2002. Dynamic Work Plan for Site Investigation and Remedial Investigation Activities - Assunpink Creek 

Greenways Project. December. 

The DWS framework allowed for shifts in decision logic to 

address new study questions and data gaps as they arose 

during the field investigation. As an example, Figure 5 

shows the sampling approach that evolved dynamically for 

the Crescent Wire site. Initial sampling locations were 

selected to delineate a potential hot spot of PCBs and 

TPH found during Phase I. However, when the real-time 

results for the samples indicated a contaminant plume 

rather than a hot spot, the decision logic shifted from hot 

spot delineation to assessing the width and source of the 

plume. Sampling along the boundary of the upgradient 

property revealed similar COCs, and sample collection 

continued along the boundary until the edges of the plume 

were identified. Now that the CSM had been substantially 

improved by the determination that the plume originated 

from an upgradient source and was confined to a thin 

layer of floating, weathered product, the decision logic 

called for a determination of whether the contaminants in 

the plume had impacted creek sediments downgradient of 

the Crescent Wire site. Under this final phase of the 

DWS, a pattern of borings was established along the 

eastern, downgradient edge of the site immediately 

upgradient of Assunpink Creek. The borings were used to 

rapidly map the extent of the PCB and TPH smear zone 

and to establish that there were no downgradient impacts 

on the creek from the site or the upgradient source. 

Overall, therefore, the DWS quickly resolved the primary 

decision questions regarding the extent of contamination 

at the Crescent Wire site in a single mobilization. 

Project Results 

The data set collected during the 4-day field program at 

the 3-acre Crescent Wire site was of sufficient quality to 

support an agreement among the stakeholders regarding 

a remedial and reuse strategy for the property. The 

project team was convinced that application of the Triad 

approach during Phase II allowed successful completion 

of the site investigation in a shorter time frame than would 

have been required by traditional approaches while 

producing a more detailed data set and greater decision 

certainty. As a whole, the Phase II investigation activities 

for AOCs along Assunpink Creek lasted less than 1 

month, and the final report was approved within 3 months 

of completion of the final dynamic work plan. 

SOURCES OF ADDITIONAL INFORMATION 

The Triad approach is encountering ever greater 

acceptance by EPA and other federal and state agencies, 

as well as by professional and industry organizations. 

Communities and project teams interested in 

implementing the Triad are encouraged to contact the 

BTSC for more information on these organizations, and for 

successful examples of Triad applications. More detailed 

information on DWSs and on the Triad approach can be 

found in the Brownfields Technology Primer Series 

document Using the Triad Approach to Streamline 

Brownfields Site Assessment and Cleanup, which is 

available at http://www.brownfieldstsc.org; see the text 

box on the first page of this bulletin. Project profiles, case 

studies, and other information on applying the Triad 

approach can be found at http://www.triadcentral.org. As 

additional bulletins about other aspects of the Triad 

approach are developed, the BTSC will make them made 

available through these web sites. 

8 
Use of Dynamic Work Strategies Under a Triad Approach 

Figure 5: Summary of Dynamic Work Strategy Implemented for Sampling of the Crescent Wire Site 

Assunpink Creek Greenways Project, Trenton, New Jersey 

Source: James Mack et al. 2003. “Characterizing a Brownfields Recreational Reuse Scenario Using the Triad Approach – 

Assunpink Creek Greenways Project.” Remediation. Autumn. 

REFERENCES NOTICE AND DISCLAIMER 

Lesnik, B. 2000. “Method Validation for the Resource 

Conservation and Recovery Act Program.” LC/GC 

Magazine, Volume 18, Number 10. October. 

This bulletin was prepared by EPA’s Office of Solid Waste 

and Emergency Response under EPA Contract No. 68-W02-034. The information in this bulletin is not intended to 

revise or update EPA policy or guidance on how to 

U.S. Environmental Protection Agency (EPA). 2000. 

“Guidance for Data Quality Assessment: Practical 

Methods for Data Analysis” (QA/G-9). EPA/600/R96/084. July. 

investigate or cleanup Brownfields or other revitalization 

sites. Mention of trade names or commercial products 

does not constitute endorsement or recommendation for 

use. 

EPA. 2000. “Guidance for the Data Quality Objectives This bulletin can be downloaded from EPA’s Brownfields 

Process” (QA/G-4). EPA/600/R-96/055. August. and Land Revitalization Technology Support Center at 

www.brownfieldstsc.org. For further information about this 

EPA. 2003. “Using the Triad Approach to Streamline bulletin or about the Triad approach, please contact Dan 

Brownfields Site Assessment and Cleanup.” Brownfields Powell of EPA at (703) 603-7196, or powell.dan@epa.gov. 

Technology Primer Series. EPA 542-B-03-002. June. 

Triad Resource Center Web Site. 2004. 

http://www.triadcentral.org/index.cfm. Accessed 

November. 

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