A Resource for MGP Site

Characterization and

Remediation

Expedited Site Characterization and

Source Remediation at Former

Manufactured Gas Plant Sites
Office of Solid Waste and 

Emergency Response (5102G)

EPA 542-R-99-005

www.epa.gov/tio

clu-in.org

May 1999

A Resource for MGP Site Characterization 

and Remediation

Expedited Site Characterization and Source Remediation

at Former Manufactured Gas Plant Sites

U.S. Environmental Protection Agency

Office of Solid Waste and Emergency Response

Technology Innovation Office

Washington, DC 20460

Notice

This report was prepared by Environmental Management Support, Inc., 8601 Georgia Avenue,

Suite 500, Silver Spring, MD 20910 under contract 68-W6-0014, work assignment 87, with the

U.S. Environmental Protection Agency. Mention of trade names or commercial products does

not constitute endorsement or recommendation for use.
i



The United States Environmental Protection Agency (USEPA), in conjunction

with states, industry trade associations (the Edison Electric Institute [EEI], the

Utility Solid Waste Activities Group [USWAG], and American Gas

Association [AGA]), and individual utilities, has compiled a summary of

innovative strategies and technical approaches for expediting site characterization

and source material remediation at former manufactured gas plant (MGP) sites.

Former MGP sites, as a category of inactive industrial waste disposal sites, contain

many similarities in historical industrial activities and the types and distribution of

MGP wastes and related contaminants. This trend, coupled with the fact that

today’s utilities are often the primary owners of (or accept remedial responsibility

for) these sites, allows both the regulatory agencies and the utilities to develop

approaches to achieving economies of scale and effort in addressing contamination

at former MGP sites. Unlike remediation sites of other industries, MGP sites are

typically not found at locations where utilities operate today, are often located in

the midst of residential communities that have developed around these abandoned

industrial locations, and are owned by entities unrelated to the modern utility.

This document was prepared by the USEPA to provide current information on

useful approaches and tools being applied at former MGP sites to the regulators

and utilities characterizing and remediating these sites. The document outlines site

management strategies and field tools for expediting site characterization at MGP

sites; presents a summary of existing technologies for remediating MGP wastes in

soils; provides sufficient information on the benefits, limitations, and costs of each

technology, tool, or strategy for comparison and evaluation; and provides, by way

of case studies, examples of the ways these tools and strategies can be implemented

at MGP sites. 

Innovative strategies for managing former MGP sites, as discussed in Chapter 3 of

this document, include multi-site agreements, dynamic work planning, teaming

approaches to expedite remedial action planning and execution, and methods for

dealing with uncertainty at these sites. Technical innovations for site

characterization (Chapter 4) include the availability of direct push and other field

screening technologies to complement traditional analytical approaches. Finally, a

variety of approaches and technologies have been employed to provide costeffective solutions to treating the wastes remaining at former MGP sites (Chapter

5).

The information presented in this document is applicable to the characterization

and remediation of former MGP sites conducted under traditional remediation

programs as well as the large number of MGP sites which are likely to be addressed

under voluntary cleanup programs.
ii

	



Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i

Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

List of Acronyms and Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.1 Background .................................................. 1-1

1.2 Purpose and Scope of Document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

2 Creating an Expedited Site Characterization and Remediation Program 2-1

2.1 Introduction .................................................. 2-1

2.2 Expedited Site Characterization and Remediation ................. 2-1

2.3 Creating the Expedited Site Characterization and 

Remediation Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

2.4 Management Tools for Expediting Characterization and Remediation 2-7

2.5 Tools for Site Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8

2.6 Technologies for Cleaning up MGP Wastes . . . . . . . . . . . . . . . . . . . . . . . 2-8

2.7 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9

3 Management for Expediting Site Characterization and Remediation . . . 3-1

3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

3.2 Management Tools for Expediting Site Characterization and 

Remediation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

3.2.1 Site Bundling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

3.2.2 Multi-Site Agreements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8

3.2.3 Generic Work Plans and Reports . . . . . . . . . . . . . . . . . . . . . . . . 3-13

3.2.4 Program/High Performance/Design Plan . . . . . . . . . . . . . . . . 3-15

3.2.5 Early Land Use Determination/Brownfields . . . . . . . . . . . . . . 3-20

3.2.6 Managing Uncertainty (Observational Approach) . . . . . . . . . . 3-24

3.2.7 Expedited Site Characterization . . . . . . . . . . . . . . . . . . . . . . . . . 3-30

3.2.8 Legislative Innovation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-36

3.2.9 Dovetailing Business Decisionmaking and Remediation

Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-40

3.2.10 Establishing Background PAH Concentrations . . . . . . . . . . . . 3-43

3.2.11 Generic Administrative Orders . . . . . . . . . . . . . . . . . . . . . . . . . 3-49
&RQWHQWV

iii

4 Tools and Techniques for Expediting Site Characterization . . . . . . . . . . . 4-1

4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

4.2 Tools and Techniques for Expediting Site Characterization . . . . . . . . 4-10

4.2.1 Direct-Push Methods/Limited Access Drilling . . . . . . . . . . . . 4-10

4.2.2 Analytical Field Screening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-26

4.2.3 Geophysical Surveys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-36

4.2.4 Soil Gas Surveys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-52

4.2.5 Contaminant Migration Evaluation . . . . . . . . . . . . . . . . . . . . . . 4-56

4.2.6 Other Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-61

5 Technologies for Source Material Treatment . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

5.2 Technologies for Source Material Treatment . . . . . . . . . . . . . . . . . . . . . . 5-1

5.2.1 Co-Burning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5

5.2.2 Thermal Treatment Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8

5.2.3 Asphalt Batching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-24

5.2.4 Bioremediation/Chemically Enhanced Bioremediation . . . . . 5-32

5.2.5 Containment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-45

5.2.6 Stabilization/Solidification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-49

5.2.7 Soil Washing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-55

5.2.8 Soil Vapor Extraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-61

6 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1

7 Additional Sources of Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
iv


		



	


AFB Air Force Base

AFCEE Air Force Center for Environmental Excellence

ASTM American Society of Testing and Materials

atm atmospheres

bgs below ground surface

BTEX benzene, toluene, ethylbenzene, and xylenes

Btu British thermal unit

CERCLA Comprehensive Environmental Response, Compensation and 

Liability Act of 1980

CERCLIS Comprehensive Environmental Response Compensation, and

Liability Act Information Systems

cis-1,2-DCE cis-1,2-dichloroethylene

CO carbon monoxide

cPAH carcinogenic polycyclic aromatic hydrocarbon

CPT cone penetrometer

CROWTM Contained Recovery of Oily Wastes

CWM Chico/Willows/Marysville

DCE dichloroethylene

DCI Dust Coating, Inc.

DEC Department of Environmental Conservation

DEP Department of Environmental Protection

DEQ Department of Environmental Quality

DMLSTM diffusion multi-layer sampler

DNAPL dense non-aqueous phase liquid

DNR Department of Natural Resources

DQO data quality objective

DRE destruction removal efficiency

DTSC Department of Toxic Substance Control

DUS dynamic underground stripping

EEI Edison Electric Institute

ELISA enzyme-linked immunosorbent assay

EMS electromagnetic survey

EPA Environmental Protection Agency

EPRI Electric Power Research Institute

ERAP Expedited Remedial Action Program

ESC expedited site characterization
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v

FS feasibility study

ft/min feet per minute

GC gas chromatography

GCL geosynthetic clay liner

GIS geographic information system

gpm gallons per minute

GPR ground-penetrating radar

GRI Gas Research Institute

ha hectare

HASP health and safety plan

HCl hydrogen chloride

HDPE high-density polyethylene

HPO hydrous pyrolysis oxidation

HPT high-performance team

IDW investigation-derived waste

IGT Institute of Gas Technology

ISM in situ bio-geochemical monitor

ISTD in situ thermal desorption

ISU Iowa State University

kg kilogram

LIF laser-induced fluorescence

LNAPL light nonaqueous phase liquids

LTTD low-temperature thermal desorption

LTU land treatment unit

MART Mid Atlantic Recycling Technologies, Inc.

MCL Maximum Contaminant Level

MEC MidAmerican Energy Corporation

MEW Missouri Electric Works

μg/L micrograms per liter

μm micrometer

mg milligram

mg/kg milligrams per kilogram

MGP manufactured gas plant

mm millimeter

MSE microscale solvent extraction

NAPL nonaqueous phase liquid

NCP National Contingency Plan

NJDEP New Jersey Department of the Environment

NMPC Niagra Mohawk Power Corporation

NOx nitrogen oxide

NPL National Priorities List
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vi

NTU nephelometric turbidity unit

NYSDEC New York State Department of Environmental Conservation

OUR oxygen uptake rate

PAH polycyclic aromatic hydrocarbon

PA preliminary assessment

PCB polychlorinated biphenyl

PCE perchloroethylene

PCP pentachlorophenol

PEA preliminary endangerment assessment

PGE Portland General Electric

PG&E Pacific Gas and Electric Company

PITT Partitioning Interwell Tracer Test

PNA polynuclear aromatic hydrocarbon

ppb parts per billion

PP&L Pennsylvania Power & Light Company

ppm parts per million

PQL practical quantitation limit

PSE&G Public Service Electric and Gas Company

psi pounds per square inch

PVC polyvinyl chloride

QA quality assurance

QAPP quality assurance project plan

QC quality control

RA remedial action

RAGS Risk Assessment Guidance for Superfund

RAP remedial action plan

RCRA Resource Conservation and Recovery Act of 1976

RD remedial design

RG&E Rochester Gas and Electric

RI remedial investigation

ROD Record of Decision

ROSTTM Rapid Optical Screening Tool

RP responsible party

SCAPS site characterization analysis penetrometer system

SI site investigation

SITE Superfund Innovative Technology Evaluation

SoCal Gas Southern California Gas Company

SO2 Sulfur dioxide

SPLP synthetic precipitation leaching procedure

SRP site remediation program

S/S solidification and stabilization
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vii

SVE soil vapor extraction

SVOC semivolatile organic compound

TCE trichloroethylene

TCLP toxicity characteristic leaching procedure

TEPH total extractable petroleum hydrocarbons

3-D/3-C three-dimensional, three-component

TPH total petroleum hydrocarbons

TSCA Toxic Substance Control Act

2D two-dimensional

UCS ultimate compressive strength

USEPA United States Environmental Protection Agency

USWAG Utility Solid Waste Activities Group

VOC volatile organic compound

WEPCO Wisconsin Energy Power Company

WRI Western Research Institute

XRF X-ray fluorescence


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1-3

The costs provided in this document are based on limited data and are dynamic.

Many variables will affect the cost of a tool or technology as applied to a specific

site or set of sites. The cost information provided herein reflects an order-ofmagnitude guide to costs, and is provided on an informational basis. 

Case studies are provided, where available. Additional examples of the

application of these strategies, tools, and treatment technologies likely exist.

Typical regional variations in MGP sites are identified where relevant or where

additional information is available. 

Detailed information on the history of former MGPs and their disposal practices

is not included in this document. For background and historical information, the

reader is referred to Chapter 7, Additional Sources of Information. 

Finally, this document specifically does not address groundwater remediation

technologies. A limited amount of information is provided on restoration of

non-aqueous phase liquid (NAPL) zones at or below the water table. This is an

area of considerable technological development. These issues may be addressed

in future guidance document volumes.
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2-1

Chapter 2

		


	

	
	




	


The process of characterizing and remediating an MGP site or sites involves

first determining what contamination is present and where. Once it is clear

what wastes are present and at what locations, a selection of treatment

and/or management alternatives can be evaluated to identify a preferred remedial

approach. Familiarity with the historical operation of MGPs, which was similar at

almost all sites, can further expedite the characterization and remediation process.

This process typically follows that which is outlined by the National Contingency

Plan (NCP) and is often modified by other federal, state, and/or local regulations.

The primary modes by which the site characterization and remediation process

can be modified to save time and costs are:

 How the site is “administered” (i.e., how investigations and cleanups are

organized and managed)

 The use of innovative and survey-level tools and approaches for expediting the

site characterization

 Awareness of and familiarity with the subset of treatment technologies that are

proven or promising for the particular types of wastes found at MGP sites

This chapter summarizes the process of streamlining the site characterization and

remediation process, by tying together approaches to site management and

contamination assessment (described in Chapters 3 and 4) with proven or

promising treatment technologies for MGP residues and wastes in soil (Chapter 5).

		


			





Twenty to twenty-five years ago, in the early days of site characterization and

environmental remediation, contaminated site work was scientific study as new

disciplines were created and refined to address the work at hand. Typically, site

work would begin with the preparation of work plans, followed by a round of

field investigations. Samples collected during the field programs were sent to

analytical laboratories for analyses, and after about a month, laboratory results

were returned and subjected to tabulation, mapping, and other types of data

evaluations. The results of the data analyses were documented in a draft report

which was distributed to the responsible party and regulatory agencies for review.

Meetings typically followed in which detailed discussions were held as to the
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2-2

“correct” interpretation of the data. Eventually, a revised report was prepared and

submitted, the conclusion of which typically included recommendations for

additional sampling. And so the whole process of work planning-samplinglaboratory analyses-data interpretation-reporting would continue until multiple

phases and many years would pass. In all, very large sums of money were spent

on “studying” the site before cleanup activities were planned, much less

implemented.

In response to outside economic influences (including experience with the

economic impacts of site characterization and remediation on businesses), the

need for additional urban lands for redevelopment (bringing the Brownfields-type

initiative to the forefront), and the maturation of the environmental marketplace,

new pressures have been brought to bear to accomplish the same tasks in a

smarter, cheaper, and more expeditious manner. For certain types of sites,

including former MGP sites, practitioners now have enough experience that they

can anticipate the nature of work to be accomplished, foresee the problems that

may arise, and select an appropriate remedy from a known subset of treatment

technologies. From a menu of technology options, practitioners can select the site

characterization and analytical methods that are most likely to yield useful

information to support site decisionmaking and remedy selection. When remedial

design options are anticipated during the planning stage, data supportive of

remedy considerations can be gathered concurrently with characterization

information. By involving stakeholders at critical junctures, community and

regulator satisfaction can be increased, decreasing the likelihood of legal battles

that may delay remedial action and consume financial resources.

Work at former MGP sites can proceed seamlessly from investigation to

remediation and closeout. With careful advance planning and the use of rapid

turnaround on-site analytical technologies, investigation and cleanup objectives

can be achieved in a fraction of the time (and thus at a lower cost) as compared to

traditional approaches which rely on a prescriptive, linear progression of phases

and tasks. Considerable time savings over the life of the project can be realized by

reducing the number of mobilizations to the field and by performing multiple task

simultaneously.

There are a number of key elements that comprise new approaches to performing

site characterization. The most critical is the need for systematic planning prior to

initiating site work. Systematic planning is one of the most cost-effective tasks in

environmental remediation. It markedly increases the likelihood that a project will

be successfully completed the first time, and within budget. It markedly decreases

the probability of unpleasant and costly surprises.

Planning should be performed by a core technical team that contains all the

expertise needed to adequately address the needs of the site, and that will

incorporate the interests and concerns of stakeholders. Expertise vital to nearly all

sites, but frequently overlooked, includes the services of a knowledgeable

analytical chemist and a statistician familiar with the special concerns of

environmental sampling. Planning involves the use of a site conceptual model

which identifies the historical uses of the site, potential exposure pathways,
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cleanup concerns, and future land-use options. Clear articulation of the decision(s)

or question(s) that drive the site work is imperative to the planning process. An

appreciation for how much uncertainty or risk is acceptable in site decisions is also

crucial (i.e., how sure must the decisionmaker be that wrong decisions will not be

made). A great deal of time and effort may be consumed reaching consensus on

these two issues, but once done, planning of the actual work to be performed at

the site can begin and proceed without interruption. 

Planning then proceeds in an orderly progression: When the site decision(s) is

known, the type of information (data) which is required to inform the

decisionmakers can be identified. When the amount of uncertainty has been

decided, the quality of the data needed to meet the uncertainty goals can be

determined. Once the type of data and the data quality needs have been

determined, then a menu of analytical chemistry methods (for contaminant data)

or sampling tools and techniques (for hydrogeological or contaminant

information) can be surveyed for a cost-effective means of gathering information.

If, during the planning process, it is found that the expense of collecting a data

point to meet very stringent uncertainty goals exceeds available resources, the

team can “go back to the drawing board,” and negotiate with stakeholders over

future land use alternatives and the degree of allowable uncertainty.

Selecting an analytical method(s) involves balancing a number of considerations:

the data needs, any regulatory requirements, costs, the ability to optimize sample

throughput to provide real-time decisionmaking and to match the speed of sample

collection, and any anticipated site-specific issues (such as matrix interference).

Method selection should be done by a qualified chemist who can weigh the costs

and benefits of various methods against site-specific data needs. 

Field analytical methods hold a significant potential for cost and/or time savings,

and should be included in the pool of analytical options under consideration. The

rapid turnaround time supports a dynamic work plan which can decrease the

collection and analysis of uninformative samples. Again, a knowledgeable chemist

is crucial to avoiding the potential pitfall of the undiscerning use of field analytics.

It is the responsibility of the chemist member of the technical team to stay on top

of rapid advancements being made in analytical environmental chemistry,

especially as they relate to field methods. Depending on the method, the skill of

the operator, and the kinds of calibrations and quality control used, some

currently available field technologies can produce results that are just as

quantitative as those expected from traditional laboratory services. The ability of

field analytical methods to address certain issues, such as defining spatial

variability across the site and minimizing the loss of volatile contaminants during

sample collection and transport, means that field analytical data can sometimes be

more reliable and representative than those generated under traditional scenarios.

Of course, the big question about the use of innovative analytical methods and

sampling tools is “Will the regulators accept the results?” In general, regulators

will often accept results from less-traditional technologies if the rationale for the

collection and use of the data has been clearly documented. It is unfortunately
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true, however, that a heavy reliance has been placed on accepted methods,

sometimes to the extent that these methods are viewed as “approved methods”

that must be used to generate analytical data at contaminated sites. However, as

part of their Performance-Based Measurement System initiative, the U.S.

Environmental Protection Agency (USEPA) is attempting to change the focus to

what data quality is required, leaving it up to the regulated entity to select the

analytical method to be used.

Finally, by blending advance planning with field analytical methods capable of

“immediately” available results, it is possible to implement dynamic work plans to

accomplish site work much more efficiently than under traditional approaches.

Dynamic work plans offer structured decision logic, such as decision trees or

contingency planning, that guides the performance of field activities. A key feature

is on-site decisionmaking and direction of field efforts by the technical team based

on an evolving site conceptual model which is constantly updated with new

information as it becomes available. Dynamic work plans use an adaptive

sampling and analysis strategy where subsequent sampling is directly contingent

on the interpretation of earlier results, which permits the collection of samples or

the installation of wells in locations where the data are truly needed to decrease

uncertainty.

To successfully implement a dynamic work plan, more experienced team members

must take charge of field work. Increased expense is justified by the increased

productivity of field work. For example, there is a decreased need for multiple

mobilizations to the field to redirect work after interpretation of results turned

around from the laboratory three to four weeks later indicate that important data

gaps (and thus uncertainty) still remain; or when it is discovered that some critical

analyses failed quality assurance checks and samples must be recollected if the

data set is to be complete. Most importantly, the quandary of whether to spend

more money on another sampling round to decrease uncertainty or whether to

“make do” with the available data is avoided. “Making do” generally means that

site decisions or remedial design will be based on inadequate information which

increases the risk that the project will ultimately fail to achieve its objectives.

Adequate site characterization is essential to define the nature and extent of

contamination so that decisions regarding site cleanup will be done in a scientific

and legally defensible yet cost-effective manner. The range of experience and

knowledge gained over the past decade is permitting the environmental

remediation field to capitalize on new technologies and new ideas. To maintain

momentum, practitioners must make the effort required to stay current with

developments in their field of expertise. As the pool of available knowledge and

technology tools continues to expand, it also becomes important to recognize that

a single person cannot be relied upon to do it all – a technical team approach

which acknowledges that contributions of geologists, engineers, chemists,

biologists, quality assurance experts, risk assessors, statisticians, and regulatory

experts is crucial to successful projects.
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A successful expedited site characterization and remediation program is formed

by careful and thoughtful advance planning. As a whole, the program can be

broken down into the following four steps or phases. Although these steps appear

to be the same basic steps as currently applied at Resource Conversion and

Recovery Act of 1976 (RCRA) or Comprehensive Environmental Response,

Compensation and Liability Act of 1980 (CERCLA) sites, the intent is to do the

project in a better, faster, and less expensive manner. During each step described

below, project implementation and management can be enhanced through the

development of relationships (and trust) between stakeholders, frequent and

effective communication, flexibility, and contingency planning.

Step 1: Preliminary Conceptual Model Formation

The first vital step in expediting site characterization and remediation is to

conduct an initial site evaluation (also known as a Phase I environmental

assessment or Preliminary Assessment) to establish baseline conditions at the site.

In this assessment, historical information about the site’s former operations are

gleaned from documents such as:

 Historical aerial photographs

 Sanborn Fire Insurance maps

 As-built site drawings

 Historical operations records

 Historical topographic maps

 Real estate records and title information

Regulatory agency site listings and files are also reviewed as are current site

practices. From this assessment, a preliminary site conceptual model is formed,

identifying what types of contaminants (if any) may be present at the site (e.g.,

petroleum hydrocarbons, PAHs, heavy metals), the possible locations of wastes

(e.g., gas holders, lampblack separators, tar pits and wells), and any immediate

health risks or threats to the environment.

Step 2: Survey-Level Field Program Formulation

Following completion of the preliminary site conceptual model, all possible

stakeholders in the project should be identified, briefed with the preliminary

conceptual model, and interviewed to obtain their input on the overall project

goals and objectives. Possible stakeholders include senior members of the

responsible parties’ organizations, regulatory agency representatives, third-party

owners, public officials, and representatives of the public as required for future

land use determination. A survey-level field program is then formulated to collect

analytical data to answer the following questions:

 What contaminants are present at the site, if any?
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 What are the relative concentrations of the detected contaminants?

 What is the approximate extent of contamination at the site?

It is here the 80/20 rule should prevail; that is, practitioners should aim at getting

80 percent of the information ultimately needed for the project in this round of

sampling. The survey-level field program should take advantage of the site

characterization and management tools listed in Chapters 3 and 4 to gather a large

amount of relatively good quality data in order to determine where the majority of

the contamination is located and its chemical composition. A limited site

investigation (SI) is usually required to collect this information.

Dynamic work planning is essential to the successful completion of this phase of

the project. Sampling and field decisionmaking protocols — rather than specific

boring locations — should be outlined in the work plan, allowing an experienced

field team to move and sample at those locations dictated by each previous

sampling point. Innovative tools should be paired and implemented to allow for

real-time on-site analytical data feedback; for example, using direct-push drilling

with grab groundwater samplers and immunoassay or colorimetric testing to

identify the presence/absence and relative concentrations of subsurface and

groundwater contamination, where practicable.

Step 3: Preliminary Treatment Technology Screening, and Focused Field

Investigation Formulation and Implementation

Following completion of the survey-level field investigation, the sampling

program’s results are analyzed with an eye toward site remediation. Those

remediation technologies that are the most promising for the site are identified, as

are the additional data points necessary to:

 Further refine estimates of contamination volume

 Gather the additional data necessary to aid in evaluation and selection of the

best remedial alternative(s) for the site (e.g., geochemical indicators of natural

attenuation to see if active groundwater remediation is necessary, soil sieve

analyses to determine grain size, soil moisture measurements to determine

effectiveness of thermal desorption, etc.)

 Collect additional site-specific data to evaluate uncertainties that may have a

significant effect on the remedy selection (e.g., Is shallow groundwater in

connection with deeper groundwater-bearing zones? May drinking water be

affected?)

From this exercise, one or more focused field investigations are formulated and

subsequently implemented to gather only those data necessary to reduce

uncertainty to a pre-determined level of comfort and as required to complete

remedy selection. Again, work planning should allow for flexibility in the field,

permitting additional data collection as deemed necessary by the experienced

project team.
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Step 4: Remedy Selection and Contingency Planning

Using the results from the focused field investigations or a full-scale subsequent

remedial investigation (RI), remediation remedies for the site are evaluated.

Taking all factors into account, a remediation selection is made. As part of the

remedy selection and remedial design process, contingency planning is conducted

to prepare for unexpected changes in site conditions during remediation. The

selected remedial program is then implemented and modified as needed to adapt

to changing site conditions in order to achieve pre-determined performance-based

standards.

The four steps described above are intended to provide a skeleton for an expedited

site characterization and remediation program. It is the responsibility of the

practitioner to use this as a guide, amending, modifying, and adapting as needed

to meet site- or project-specific conditions. There are many variables that will

influence the form, scope, and level of effort involved for a site characterization

and remediation program. For example, site attributes that may affect the tools

used to characterize the site include:

 Site size

 Hydrogeology complexity

 MGP feedstocks used

 Availability of background and historical information

The tools described in general below and in detail in subsequent sections of this

document have been selected as those most applicable and available for

formulating an expedited program at former MGP sites. Logic and experience will

aid in formulation of an appropriate site-specific program.

			 	!	



	
	


The process of MGP site characterization and remediation can be expedited by a

number of management or administrative approaches. Underlying all these

approaches is the need for trust and communication among those with an interest

in the site: the site owner, responsible party, regulators, consultants, the public,

area residents, etc. Actively involving all stakeholders in the process and creating

teams under conditions that foster genuine cooperation are key to facilitating

cleanup. If there is trust among all parties involved, there can be flexibility to make

decisions in the field as new information is uncovered about the site, without

slowing the process down for repeated reviews of new documentation. Effective,

cooperative relationships can be fostered by establishing administrative structures

and procedures, and/or by chartering teams of stakeholder representatives on a

project-by-project basis. 

Practical strategies for streamlining MGP site characterizations and remediations

are discussed in Chapter 3 and include grouping together nearby or similar sites
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and negotiating agreements for groups of sites rather than on a site-by-site basis;

creating templates for work plans, reports and administrative orders; and knowing

early in the process what the eventual use of a site will be so cleanup can be

targeted to levels appropriate to that future use. Risk analyses, in the form of

tiered or probabilistic risk assessments, can also be used to help establish

appropriate cleanup objectives and to aid in the comparison of risks and liability

that could remain if various remedial alternatives were implemented. In addition,

use of the observational approach to site management can help focus the project

on targeting the information needed to assess contamination, getting only as much

information as needed to evaluate remedial alternatives, and planning for new

information that might emerge about the site as cleanup proceeds rather than

trying to eliminate all uncertainties before remediation can begin.

"		 	!		

All of the management strategies summarized above rely on targeted field

investigations in which sampling locations are chosen based on knowledge of a

site’s past layout, and on the use of tools that are generally faster and give more

immediate results than those used in the past for assessment and cleanup of

wastes. Many samples can be collected, and a large amount of survey-level data

can be generated in a short time using these innovative tools. 

Field surveying tools described in Chapter 4, from direct-push drilling to methods

for rapidly sampling soil and groundwater to the use of imaging techniques to

locate underground structures, make the process of collecting data on the types,

concentrations, and locations of MGP wastes much more rapid than in the past. If

management strategies such as site bundling are also used, multiple sites can be

assessed together or sequentially, taking advantages of economies of scale.

After the first phase of an investigation has been completed using field surveying

tools, further, focused investigations can supply additional data about areas of

contamination or uncertainty. This document focuses on tools for rapid field

surveys. In some cases, regulators may require data that these tools cannot provide

(e.g., low concentrations of PAHs in groundwater). However, because effective

field surveying can determine where the majority of the contamination occurs at a

site, traditional, time-intensive monitoring (e.g., fixed monitoring wells) to gather

additional data can be used only where necessary, saving time and money

compared to using these traditional methods to assess the whole site.

#		 	!		$	%	&  

Familiarity with the technologies that have proven effective for treating MGP

wastes (as described in Chapter 5) may save time in identifying those candidates

most applicable to a specific former MGP site. Consider the choice between on-site

or off-site asphalt batching and thermal desorption as a treatment for

contaminated soil. Since both technologies will produce approximately the same
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result, considerations such as the amount and types of soil to be treated, the

proximity of the MGP site to an off-site fixed facility, and the costs associated with

these factors will likely motivate the decision.

'		 

The ability to craft an effective, streamlined site characterization and remediation

program comes from both experience and knowledge. Understanding how MGPs

were operated and dismantled is the first step — gaining an understanding of

what might be below the surface of a site is extremely important. Flexibility,

combined with careful planning and the willingness to try something new, can aid

in the formulation and successful implementation of an innovative and

streamlined investigation and remediation program.

The management strategies and field-survey tools described in this guide will

provide information necessary to expedite the site characterization and

remediation process. The technologies described are those most likely to be

effective in remediating MGP wastes in soils, delineated by this streamlined

process.
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3-1

Chapter 3

	













Because of the similarity of former MGP sites nationwide, innovative site

management tools have been developed to streamline the characterization

and remediation of wastes found at these sites. Using these techniques can

reduce the timescale that has been typical for remedial investigation, feasibility

study, remedial design, and remedial action (RI/FS/RD/RA) cleanup projects at

sites being addressed under traditional programs. These innovative approaches,

described below, have two key features: they take advantage of economies of

scale, emphasizing ways to address multiple sites simultaneously; and they focus

on facilitating communication among the parties involved in cleanup as well as

promoting each party’s “ownership” of the process. The table on the following

pages summarizes the components of these programs.

These site management innovations are currently being applied at MGP sites. Case

studies are included below where available. Not every tool will be appropriate in

every situation. Parties responsible for former MGP sites can modify the

approaches to fit their sites. Similarly, responsible parties can select more than one

of the tools discussed below and merge them to tailor a program to a site or set of

sites. Reference information is supplied so that readers can contact representatives

involved in the specific projects.
3-2

Management Tools for Expediting Site Characterization and Remediation

Name Description Economies of Scale Advantages Communication Facilitation

Site Bundling Bundling multiple MGP sites into one

"package" which is then managed,investigated, and as appropriate, remediatedas a single entity.

• Saves time and money by reducing the volume ofpaperwork• Allows for negotiation of lower unit pricing with vendors• Reduces project management and accounting coststhrough reduction in project administration labor hours• Reduces regulatory agency oversight costs bynegotiation one order for multiple sites and having oneregulatory project manager

• One regulatory project manager for multiple sitesminimizes downtime from lack of education/projectunderstanding• Minimizes duplication in RI/FS/RD/RA programdevelopment• Builds trust/relationship between stakeholders byprolonged, multi-site contact

Multi-Site Agreements Single agreement providing responsible

party(ies) and regulatory agency(ies) theopportunity to address environmentalconditions under a single, cooperative,mutually beneficial, statewide agreement.

• Comprehensive and consistent statewide strategies• Reduced costs of negotiating agreements/orders• Control of year-to-year costs• Optimized risk reduction

• Agreements tailored to company-specific needs• Central point of contact(s) established within regulatoryagency(ies)• Proactive environmental mitigation• Emphasis on cooperation and common sense

Generic Work Plansand Reports

Preparation of generic documents, such aswork plans and reports, that can be tailoredto a specific site or set of sites.

• Savings from having to prepare only the site-specificsections of a document• Reduced regulatory oversight costs and review timefrom having all documents from a single entity beorganized similarly

• Streamlined decisionmaking from "prequalifying"remediation technologies with local regulatory agencies• Consistent site characterization and application of qualityassurance project plans and Health and Safety Plan acrossmultiple sites• Consistent decisionmaking rationales applied to multipleMGP sites

Program/High Performance/Design Teams

A team or set of teams formed andchartered to work towards a common goal,promoting communication, expeditingdecisionmaking, streamlining deliverablepreparation, and remediating a site in themost cost- and time-effective mannerpossible with agreement among all partiesinvolved.

• Shared project vision, mission, and goals for all sitesaddressed by the team• Reduces overall costs by minimizing documenthandling and review and project downtime• Reduces overall regulatory oversight costs• Minimizes downtime and backsliding resulting fromconsultant or regulatory management turnover

• Chartering and common sense of purpose and set ofgoals promotes communication• Success of team(s) based on development of relationshipand trust• Nature of team reduces stakeholder conflict• Team charter formalizes communication process

Early Land-useDetermination/Brownfields

Identification of future site beneficial useprior to site characterization, and integrationof the proposed future land use with theplanned site remediation.

• Reduces site characterization costs by identifying onlythose data necessary for evaluation of remediationalternatives to meet proposed future site use• Minimizes remediation costs by focusing onalternatives that can successfully meet future beneficialuse needs• Can turn a challenged property into a money-makingenterprise

• Focuses regulatory agency(ies) and responsible partieson the project’s ultimate goal (site remediation andredevelopment)
3-3

Management Tools for Expediting Site Characterization and Remediation

Name Description Economies of Scale Advantages Communication Facilitation

Managing Uncertainty A method providing a way to determine when

sufficient site characterization data have beencollected and involving managinguncertainties through the identification ofreasonable deviations from original plans andthe preparation of contingency plans toaddress changed site conditions. 

• Minimizes downtime during site characterization and/orremediation through upfront contingency planning toaddress potential changes in site conditions

• Requires flexibility to alter a site investigation and/orremediation in the field based on pre-determinedcontingency plans. This requires trust and consistentcommunications between regulatory agency(ies) andresponsible party(ies)

Expedited SiteCharacterization

The combination of tools, strategies, andprocesses that interlink and synergisticallyhelp streamline investigation and remediationprocesses.

• Reduced costs through streamlined documentpreparation and review• Reduced costs through the use of field screening andanalysis tools• Minimizes project downtime by allowing flexibility in theoverall site characterization and remediation processesand through the active management of uncertainty

• Communication and cooperation among responsibleparties, regulatory agencies, and third party stakeholdersthrough mediation, facilitation, and high-performance teams• Uses onsite or rapid decisionmaking capabilities• Includes a process for reducing team member turnoverand minimizing effects of team member replacement

Legislative Innovation Alternative regulatory policies for the

remediation of contaminated properties byproviding for a comprehensive program thatincludes revised liability, indemnificationprocesses, risk-based cleanups, streamlinedremediation processes, and disputeresolution.

• Allows risk-based decisionmaking to optimizeremediation alternatives• Apportionment of liability based on fair and equitableprinciples and orphan share funding• Saves cost by expediting site remediation

• Lead agency designation streamlines regulatory agencycommunication• Requires public participation per state regulatoryguidelines

Dovetailing BusinessDecisionmaking andRemediation Planning

Combining site remediation with businessventures such as developing affiliatecompanies or developing joint venture tocreate a mobile treatment facility.

• Optimize treatment costs by investing in risk-sharingtreatment ventures

N/A

EstablishingBackground PAHConcentrations

Establishing the portion of PAHs at a site thatare the result of non-MGP processes such asautomobile exhaust, crude oil processing, etc.

• Optimizes volume of soil to be remediated byaddressing only those portions of PAH-contaminated soilthat are the result of historical MGP processes

N/A

GenericAdministrative Orders

Preparation of a single generic administrativeorder that can be adapted for multiple sites.

• Streamlines the administrative order preparationprocess• Reduces costs in preparing and negotiatingadministrative orders

• Familiarity with the generic order allows for site-specificcommunications/ negotiations on an as-needed basis
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The following sections describe each site management tool for expediting site

characterization and remediation. Because different tools will be appropriate for

different sites, no attempt has been made to rank the tools according to their

effectiveness.

 

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Utility companies typically own or are liable for multiple MGP sites. There are

many methods that can save time and money during site characterization and

remediation. One simple but effective method is bundling multiple MGP sites into

one “package,” which is then managed, investigated, and remediated as a single

entity. Site bundling saves time and costs by:

 Reduction in the volume of paper documentation (e.g., one work plan may be

prepared for multiple sites)

 Reduction in project management and accounting costs through a reduction in

the number of labor hours required for project administration

 Reduction in regulatory agency oversight costs by negotiating one order for

multiple sites and by requiring only one regulatory agency representative for

the sites

Additional savings can be achieved by coordinating site investigation and

remediation activities for multiple sites located relatively close together.

Mobilization costs can be reduced by conducting sampling (e.g., quarterly

groundwater monitoring) sequentially at all sites and by purchasing sampling

materials in bulk. When the preferred remedial alternative is the same for multiple

sites and especially in situations where the sites are located near one another,

treatment costs can be reduced by staging treatment processes for all the sites at

one location. Savings result from reduced transportation costs and lower unit costs

for treating larger volumes of material than would be generated by a single site.

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At the end of 1996, MidAmerican Energy Company (MEC) was preparing to

conduct remedial activities at a number of former MGP sites that were relatively

close to each other. These sites had fairly small quantities of waste to be treated

and were of limited size, which posed potential problems for locating treatment

technologies on-site. Because of the sites’ proximity, small size, and ownership by

one utility, innovative administrative and technical approaches were chosen.

On-site thermal desorption by a mobile treatment unit was identified as a viable

remedial alternative for all of the sites. MidAmerican Energy worked with the

Iowa Department of Natural Resources (DNR) and USEPA Region VII to locate a

thermal desorber at a National Priorities List (NPL) site in Waterloo, Iowa.
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Following completion of a rigorous trial burn, the thermal desorption unit was

used to treat MGP wastes at the Waterloo site and from three additional sites in

Charles City, Hampton, and Independence, Iowa.

Project Milestones

Initially, Independence, Iowa, was the only MEC site where contaminated soils

were to be excavated and thermally treated. As the planning for this project

proceeded, it became apparent the thermal desorption unit could not be set up onsite because of lack of space. A search began to find a treatment location. An

industrial park in Independence appeared to be the first choice. However, the high

costs of this choice meant that another option had to be considered. The Waterloo

former MGP site in Waterloo, Iowa, already had 12,000 cubic yards of soil

removed for treatment, and this site was located 30 miles from Independence. An

open excavation existed at Waterloo, and more soil required excavation.

Concurrently, MEC determined that removal actions at the Charles City and

Hampton former MGP sites would also be beneficial if soil treatment could be

arranged. MEC therefore concluded that treatment of excavated contaminated

soils from all four sites at one on-site location could be a tremendously costeffective way to conduct removal actions at all four former MGP sites.

Site Waterloo Hampton Charles City Independence

Size (acres) 3.4 0.6 1 0.4

Service

Years

1901 - 1954 1906 - 1937 1909 - 1949 1880 - 1947

Current Site

Use

vacant electric substation/

storage area

electric

substation

vacant

Gas Process

Used

coal carbonization,

water gas,

carbureted water gas

Lowe Water Gas

System

Lowe Water

Gas System

J.D. Patton Oil

Gas Process,

Tenney Water

Gas Process

Regulatory

Status

Under consent order

with USEPA Region

VII

Under consent order

with Iowa DNR

Under consent

order with Iowa

DNR

Under consent

order with Iowa

DNR

A summary of the projects milestones is shown below:

 January and February of 1997 - MEC contacts the city managers of

Independence, Charles City, and Hampton, Iowa, to discuss the potential

remediation of the former MGP sites.

 March and April 1997 - Additional meetings with Iowa DNR and USEPA take

place to discuss the possibility of locating a thermal desorption unit at the

Waterloo site and thermally treating soils from the other three sites, thermally

desorbing the remaining soil at the Waterloo site, and using all the thermally

treated soil as backfill at Waterloo.
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 May 1997 - MEC adds the Hampton, Charles City, Waverly, and Waterloo sites

to the Independence thermal desorption project, and initiates community

relations activities in preparation for the project. 

 July 1997 - A Thermal Desorption Scope of Work and Contract Documents

package is completed. MEC continues to work with the Iowa DNR to develop

work plans for the sites under state regulatory oversight and with the USEPA

concerning the scope of work at the Waterloo site.

 October 1997 - Final changes are made to the work plans for Hampton, Charles

City, and Independence sites. Site preparation begins at Waterloo, with soil

excavation initiated at the Hampton site and soil shipping to Waterloo. 

 December 1997 - Thermal desorption operations begin in January 1998. Soil

excavation continues at all four sites, with thermal desorption operations

continuing at the Waterloo site. 

 February 1998 - All work, including backfilling, is completed.

Remedial Action Implementation

The cleanup objective at these sites was to remove visibly contaminated soil and to

excavate to physical limits, which were determined by site conditions such as

buildings, property boundaries, railroad tracks, etc. The criteria for stopping the

excavation short of a physical boundary were less than 500 milligrams per

kilogram (mg/kg) total PAHs or less than 100 mg/kg total cPAHs (cPAHs) in the

0- to 6-foot range, or less than 3,000 mg/kg total PAHs or less than 200 mg/kg

cPAHs at depths greater than 6 feet. The cleanup criterion for the thermally

treated soil was less than or equal to 5 mg/kg total PAHs.

The following table shows the amount of soil excavated and treated for each of the

four sites:

Site Tons of Soil Treated

Hampton 3,651

Charles City 2,138

Independence 4,734

Waterloo 14,167

Total 24,690

Treated soils from all four sites were used to backfill a previous excavation at the

Waterloo site. All contaminated oversized debris was crushed and thermally

treated. Some exceptionally large debris, such as foundations, was decontaminated

in place and left in the excavation. All scrap steel was cleaned and sent to a

recycler. As a result, nearly all materials removed were thermally desorbed or

recycled. A small amount of material, primarily wood debris and tree roots, was

taken to the local landfill.
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The total cost of the project was $2 million. This cost includes site preparation and

installation of utilities; excavation at all the sites; hauling excavated material from

Hampton, Charles City, and Independence to Waterloo; backfill and labor to place

the fill; and the thermal desorption services including the cost of fuel. 

The average cost per ton of soil treated was calculated for the project and is shown

in the table below:

Item Average cost per ton ($)*

Excavation 4.83

Thermal Treatment 47.87

Transportation 12.53

Backfill 4.83

Miscellaneous* 8.62

Total 78.68

* This includes the cost of analysis, engineering services, air monitoring, etc.

Conclusions

Site bundling resulted in total savings of more than $1 million on this project. The

use of a single, central location for treatment of contaminated materials resulted in

significant savings compared to the cost of completing the four projects separately;

MEC has estimated a savings in excess of $150,000 in costs related to project

management. Additional savings of approximately $205,000 were realized by

using the treated soil as backfill at the Waterloo site rather than landfilling the

treated soil and purchasing clean backfill. Setting up the thermal treatment unit in

Waterloo, a central location relative to the other sites remediated, reduced

shipping costs. Previous work at the Waterloo site had included shipping soil to

the Neal Generating Station near Sioux City, Iowa. By setting up the thermal

desorber in Waterloo, MEC saved approximately $575,000 in soil shipping costs.

Reduced regulatory oversight and engineering costs were estimated to be in excess

of $100,000. 

Teamwork was a key component to the successful completion of this project. Iowa

DNR and USEPA Region VII personnel reviewed and commented on documents

for this project. Because MEC wrote the work plans in-house, the time required to

make a change to a work plan and send an updated copy to the regulators was

very short. At times a change would be suggested, the pages of the work plan

were modified, and copies of the changes were faxed within hours of the

discussion. This fast pace kept everyone involved focused on completing the task.

Joint effort by state and federal agencies resulted in achieving the goals of site

source removal, thermal treatment, and backfill at four sites in a short time.

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Johanshir Golchin, Iowa Department of Natural Resources, (515) 281-8925
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Jim Colbert, USEPA Region VII, (913) 551-7489

Sam Nelson, MidAmerican Energy Company, (712) 277-7851

Dan Klimek, MidAmerican Energy Company, (712) 277-7930

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Former MGP sites lend themselves to multi-site agreements. Much like strategic

plans, multi-site agreements provide both the responsible party(ies) and the state

in which the properties are located the opportunity to address environmental

conditions under a single, cooperative, mutually beneficial, statewide agreement.

Benefits of multi-site agreements include:

 Comprehensive and consistent statewide strategies

 Reduced costs of negotiating agreements/orders

 Agreements tailored to company-specific needs

 Control of year-to-year costs

 A central point of contact that may be established within the state regulatory

agency

 Proactive environmental mitigation

 Optimized risk reduction

 Emphasis on cooperation and common sense

Multi-site agreements have currently been implemented in California, Iowa, New

York, and Pennsylvania. In all cases, multi-site agreements are developed through

negotiations among utilities/companies and regulatory agency(ies) and include a

strategic plan for addressing and completing site investigation and remediation.

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The state of Pennsylvania has developed a statewide program for multi-site

remediation agreements under the Department of Environmental Protection,

Bureau of Land Recycling and Waste Management. Under the Pennsylvania

Department of Environmental Protection (DEP) Multi-Site Remediation

Agreement program, utilities and other private parties may enter into a form of

consent agreement that is fundamentally different than the agreements enforced

for parcels owned by individual owners. Instead of imposing requirements with

respect to each individual site, the Pennsylvania multi-site agreements require that

a specific minimum increment of work be performed each year at the covered sites

taken as a whole. A point system is used to measure the work completed, thereby

ensuring permit compliance. To a large extent, the volume and type of work

performed during a particular year is within the discretion of the business owner.

The Pennsylvania multi-site agreements include seven primary elements that

distinguish them from other DEP-enforceable remediation agreements:
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Element 1: Planning Process—Under the Pennsylvania DEP Multi-Site

Remediation Agreement program, a company entering into an agreement with

DEP is required to submit an annual and 5-year plan incorporating the following

items:

 Identification of anticipated work during the next 1- and 5-year periods

 A list prioritizing the sites covered by the agreement

 The number of points to be earned by the anticipated work

 The estimated costs to be incurred during the next year of work

Under this program, it is the DEP’s responsibility to assemble a team including

representatives from both regional and central DEP offices, to disseminate

information among this team during the course of the agreement, and to respond

to submittals with a single set of comments. Any disagreement within the DEP

team for the sites must be resolved internally to provide consistent regulatory

review and oversight.

An annual planning meeting is held between the party responsible for the sites

and the DEP, providing an opportunity to review the proposed plans in a

cooperative manner, resolve outstanding issues, and discuss implementation of

the agreement.

Element 2: Prioritization of Sites—As noted above, the annual plan is required to

prioritize the sites to be covered by the agreement. This prioritization is conducted

by evaluating the environmental and human health risks posed by each site and

assigning points based on a scoring system that identifies the features that

potentially pose the greatest risks. The scoring system varies by agreement and is

included as an attachment to the multi-site agreement. This method of risk-based

scoring promotes DEP’s goal of risk reduction and helps the party responsible for

the sites address its areas of highest liability first.

Element 3: Point System/Minimum Annual Point Requirement—The key feature

of Pennsylvania DEP’s Multi-Site Remediation Agreement program is the point

system that measures success in completing remediation activities. Rather than

dictating which sites require which activities, the DEP and the party responsible

for the site create a list of anticipated components of work required to investigate

and remediate the sites covered by the agreement. Points are assigned to each

component based on various criteria (or combinations of criteria), including level

of effort, cost, environmental benefit, and risk reduction. The DEP and the

responsible party then determine the minimum number of points to be completed

annually under the agreement, which allows the responsible party the freedom to

determine which activities will be conducted in any given year. Failure to meet the

minimum annual point requirements may result in penalties and the requirement

to “make up” the shortfall in a specified period of time. Conversely, if the

responsible party achieves more than the minimum annual point requirement in a

given year, it may bank or save the “extra” points and apply them in a subsequent

year.
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Element 4: Cost Cap—The Pennsylvania DEP is willing to include a cost cap in its

multi-site agreements, allowing a responsible party to fall short of its minimum

annual point requirement should its total annual costs meet or exceed the cap. The

costs that are included in this cap are open to negotiation. The cap gives the

responsible party fiscal protection should remediation activities at one particular

site turn out to be significantly more expensive than anticipated. In order to

include the cost cap in a multi-site agreement, the responsible party must make a

financial disclosure.

Element 5: Uniform Process for Review and Approval of Submittals —

Pennsylvania’s multi-site agreements, like all enforceable agreements in the state,

must identify the type and contents of plans and reports to be submitted. Because

Multi-Site Remediation Agreement documents require review by a DEP team, a

uniform process for review and approval of submittals is also included in the

multi-site agreement. Establishing this process during the agreement preparation

means that requirements can be applied consistently. The review process can also

be streamlined and potentially contentious issues can be resolved up front.

Element 6: Termination —All multi-site agreements prepared by the DEP allow

for termination of the agreement by either party upon the agreement’s fifth

anniversary and every fifth anniversary thereafter. The agreement is limited to a

minimum of 5 years, which allows the responsible party to “test the waters”

without committing to a long-term process.

Element 7: Interaction with Act 2—Act 2, Pennsylvania’s Land Recycling and

Environmental Remediation Standards Act, establishes environmental

remediation standards to provide a uniform framework for cleanups. Under this

act, responsible parties can choose from three types of cleanup standards:

background standard, statewide health standard, or site-specific standard. Act 2

describes submission and review procedures to be used under each of the three

cleanup standards and provides releases from liability for owners or developers

where the site has been remediated according to the standards and procedures of

the Act. Under the Pennsylvania DEP’s Multi-Site Remediation Agreement

program, interaction with Act 2 has, to date, been agreement specific. The Penn

Fuel Multi-Site Agreement (discussed below) required the achievement of an Act 2

standard but also allowed DEP to issue a no-further-action letter in lieu of an Act 2

release, thereby relieving Penn Fuel from some of the administrative requirements

of Act 2 (Rader, 1997).

Benefits achieved under the Pennsylvania DEP Multi-Site Remediation Agreement

program include (Commonwealth of Pennsylvania, 1996a):

 Development of case loads that are manageable by both the DEP and the

responsible party

 Reduction of review time and inconsistent responses through the development

of the uniform process for review and approval of submissions

 Cost savings from managing multiple sites simultaneously and reducing

redundant administrative tasks
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 Creation of good will among DEP regions and central office and with the

regulated community

The primary disadvantage of the program is the potential deferral of remediation

at some of the covered sites. However, by actively managing the sites requiring

investigation and remediation and providing credits for work completed ahead of

schedule, both DEP and the responsible parties can minimize risk within the

context of limited resources.

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In 1995, Pennsylvania Power & Light Company (PP&L) entered into a multi-site

agreement with the Pennsylvania DEP. This agreement formed part of the

foundation of Pennsylvania DEP’s current Multi-Site Remediation Agreement

program. Under this multi-site agreement, PP&L and DEP agreed to develop a

model to rank almost 130 potential contaminated sites, including utility poles,

substations, power plants, and former MGP sites. To create this model, PP&L and

DEP first developed a uniform polychlorinated biphenyl (PCB) standard for all the

sites so PP&L could manage the project with consistent interpretations from

different DEP regional offices. Next, a system for prioritizing the sites was

devised, and a method for tracking progress was designed. A point system was

developed to ensure that PP&L kept its cleanup efforts on schedule, and an annual

financial cap was set, allowing the company to allocate financial resources over

several years (Winsor, 1996). 

An example of a former MGP site remediated under the PP&L multi-site

agreement is the Lycoming College redevelopment project. At this site, PP&L

worked with the college and DEP to remove coal tar left from two large

underground holders remaining from the original MGP (PP&L, 1996). 

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Don Stringfellow, PP&L, (717) 769-7535

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Penn Fuel Gas, Inc., (Penn Fuel) and North Penn Gas Company (North Penn)

entered into a multi-site agreement with the Pennsylvania DEP to investigate, and,

where necessary, remediate 20 former MGP sites using standards from the Land

Recycling Program (Act 2) and to plug 340 abandoned natural gas wells

(Commonwealth of Pennsylvania, 1996b). Signed on March 27, 1997, the

agreement between DEP, Penn Fuel, and North Penn Gas Company stipulated

that, during the following 15 years, Penn Fuel would investigate all 20 of the sites,

cleaning up those that require remediation following a schedule based on the

potential environmental and health risks, if any, posed by each site. North Penn

has also agreed to plug a minimum of 16 abandoned wells per year, with all 340

plugged by the year 2011. Penn Fuel and North Penn have agreed to spend up to a

total of $1.75 million a year on investigation and cleanup operations and well

plugging.
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The Lewistown former MGP site was remediated by Penn Fuel under a multi-site

agreement. Built in the early 1800s, this large MGP stood on the southern end of

Lewistown, Pennsylvania. At the end of 1996, only two of the former MGP’s gas

holders remained. Under the multi-site agreement, Penn Fuel removed 100,000

gallons of coal tar and 625,000 gallons of water from inside the two gas holders

and then dismantled the tanks. Water from the gas holders was pumped through

an oil-water separator and treated with a dual carbon treatment system before

disposal. The coal tar was pumped into treatment tanks and blended with a

polymer to dewater the tar. The steel from the gas holders was recycled in a steel

foundry. 

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Niagara Mohawk Power Corporation (NMPC) currently owns 24 former MGP

sites, all inherited from predecessor companies when it was founded in 1950.

Twenty-two of the former MGP sites are subject to two consent orders between

NMPC and the New York Department of Environmental Conservation (DEC); the

two other sites are being addressed separately.

The first of two DEC orders between NMPC and DEC calls for NMPC to:

 Investigate, between 1992 and 1999, coal tar and other wastes at 21 of the

former MGP sites currently owned by the company to determine whether any

hazardous substances are present and whether they pose a significant threat to

the environment or to public health.

 Remediate each site where DEC determines that remedial process is required.

Where deemed appropriate, interim measures may be undertaken to remove

or control sources of contamination.

Under the second consent order, NMPC will expand and complete the cleanup

already under way at the Harbor Point former MGP site in Utica, New York, to

include adjacent parcels containing MGP wastes. In addition, the company

committed to operate a research center at Harbor Point to evaluate several new

technologies for remediation of waste-contaminated materials and to fund in

advance DEC’s expenses for environmental monitoring, oversight, and

administrative costs (New York State Department of Environmental Conservation,

1992).

Under a third consent order that was executed in 1997, NMPC and the DEC

expanded the first and second orders to include remedial programs for certain

additional sites (including non-MGP sites) to:

 Level future annual costs to be incurred for site investigation and remediation

(SIR) activities

 Minimize the impact upon ratepayers of excessive short-term expenditures for

concentrated SIR activities

 Minimize potentially excessive burdens on staffing and administrative

resources of both NMPC and the DEC
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NMPC and the DEC agreed to implement an annual cost cap for SIR activities

based on the level of annual costs incurred in recent years.

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Michael Sherman, Niagara Mohawk Power Corporation, (315) 428-6624

Jim Harrington, NY State Department of Environmental Conservation, (518) 457-

0337

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In the site investigation and remediation process, documentation costs leading up

to the remediation can be very high. The traditional RI/FS/RD/RA approach

typically requires the preparation of one or more versions of a work plan and

investigation report (often multiple work plans and reports for multiple phases of

work), feasibility study reports, RA plans, removal action work plans, and closure

reports. For utilities or private parties with portfolios containing multiple MGP

sites, significant savings can come from reducing the costs of documenting and

reporting. These savings can result from either preparing single submittals for

multiple sites and/or multiple phases of work, or from preparing generic

documents that can easily be tailored to a specific site or sites.

Most generic submittal development efforts have focused on field investigative

work plans and feasibility studies. Benefits that can be achieved through the

preparation of generic templates for these documents include:

 Savings from having to prepare only the site-specific sections of a work plan or

feasibility study

 Reduced regulatory oversight costs and review time from having all

documents from a single entity be organized similarly

 Streamlined decisionmaking from “prequalifying” remediation technologies

with local regulatory agencies (e.g., development of presumptive remedies)

 Consistent site characterization and application of quality assurance project

plans (QAPPs) and Health and Safety Plans (HASPs) across multiple MGP

sites

 Consistent decisionmaking rationales applied to multiple MGP sites

A key factor in the successful application of generic work plans and feasibility

studies is allowing flexibility to move outside the template as necessary for sitespecific conditions. Combined with other streamlining strategies (e.g., multi-site

agreements), the use of generic deliverables can provide a great time and cost

savings to responsible parties and regulatory agencies.
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In April and May of 1995, Public Service Electric & Gas Company (PSE&G) met

with the New Jersey Department of Environmental Protection (NJDEP) to discuss

the potential to work with the NJDEP Site Remediation Program (SRP) to

streamline the MGP site remediation process. As a result, an NJDEP/PSE&G

Streamlining Team was established. In partnership, the two organizations defined

and evaluated the process of investigating and remediating MGP sites and

identified opportunities for improvement, consistency of approach, and cost

effectiveness. The Streamlining Team identified the quality of the RI workplan

submittal as a major area for improvement. The inadequacy of the documents

coupled with the separate review and approval cycles of the two organizations

considerably lengthened the RI process. The Streamlining Team’s solution was to

develop a boilerplate RI work plan that met or exceeded NJDEP’s technical

regulations and guidelines.

In November 1997, PSE&G published a Generic Remedial Investigation Work Plan

(PSE&G, 1997). This work plan outlined a data quality objective (DQO) process

designed to gather and evaluate all the data necessary to complete an RI in one

phase. The DQO process consists of six steps that, when completed, should

provide all the data necessary to meet NJDEP’s requirements. The six steps are:

Step 1: Understand the MGP facility’s history, construction, and operations as they

relate to the production and disposition of MGP residuals and the potential

for release(s) to the environment.

Step 2: Use the results of Step 1 and the preliminary assessment and site

investigation (PA/SI) to develop a preliminary site conceptual model.

Step 3: Develop a vision for future land use, preferably supported by a wellresearched, site-specific plan.

Step 4: Develop risk-based RA objectives that define the purpose of the

remediation and avoid expenditures on remedial activities that do not meet

these objectives.

Step 5: Identify potential remedial methods, proven to be effective at former MGP

facilities, that will achieve the RA objectives.

Step 6: Identify applicable regulatory requirements.

The Generic Remedial Investigation Work Plan prepared by PSE&G consists of

three volumes. The first volume is the generic work plan itself, containing boiler

plates for the descriptive portion of the work plan (e.g., site background,

environmental setting, and scope of work). Volume 2 of the work plan contains

the QAPP, Standard Operating Procedures for many field activities (e.g., cone

penetrometer surveys, rock coring, and aquifer testing), and a list of the minimum

safety and health plan requirements and specifications. PSE&G is currently

planning to publish a generic RI report in concert with NJDEP.
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Rich Blackman, Public Service Electric & Gas, (973) 430-8278

Chris Kanakis, New Jersey Department of Environmental Protection, (609) 633-

1460

Woerner Max, Public Service Electric & Gas, (973) 430-6413

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Faced with investigation and remediation of multiple MGP sites, Southern

California Edison (Edison) prepared a “generic FS” to help streamline preparation

of site-specific feasibility studies for their MGP sites. This generic FS template is

organized like a site-specific FS and contains text that can remain in a site-specific

FS, but it also allows the user to “plug-in” site-specific information as appropriate.

For example, the document provides a general history of MGP facilities and then

prompts the user to add site-specific historical information. The generic FS also

provides numerous examples of text and tables to further assist users in preparing

a site-specific FS. In all cases, the generic FS assumes:

 The MGP waste is nonhazardous.

 Onsite ex situ remediation is not feasible because of space limitations at the

sites.

 The cleanup level is 1 ppm total cPAHs (benzo[a]pyrene equivalent).

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Terry Sciarotta, Southern California Edison, (626) 302-9723

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A Program, High Performance, or Design Team is a team of stakeholders brought

together with the intention of creating trust, communication, motivation, and

cooperation to collectively solve a problem. Site characterization and remediation

is one of many fields in which the use of such a team can expedite, streamline, and

reduce the cost of completing a project, with the project being site-specific (as for

an MGP site characterization and remediation) or programmatic (e.g., to establish

methodologies for dealing with multiple MGP sites) in nature.

A team approach is useful because characterization and remediation of sites:

 Is often too complex for any one person to be able to know of or handle

multiple variables.

 Typically has no single solution. The best solution is often one that balances the

needs of all stakeholders involved in the site with federal, state, and local

regulations.

 Requires multiple areas of expertise to reach a preferred solution.

 Requires that all stakeholders work together to efficiently achieve an acceptable

solution.
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A High Performance Team (HPT) must concentrate on three major areas where

team development typically occurs: problem-solving skills, process improvement,

and behavioral performance. The team must learn to work together, be flexible,

and be willing to understand and develop team-related problem-solving skills

(such as Total Quality Management techniques including causal loop diagraming,

popcorn brainstorming, and decision science models). The rules of conduct laid

out in the charter must be followed, and the team must regularly revisit its

purpose, goals, and methods, seeking individual and team feedback for

continuous improvement. At times, a trained facilitator may be required to

manage the team-building process and/or to assist the team in overcoming road

blocks in the consensus-making process.

Building a team requires time and energy. Effective teams create synergistic

results. Beyond pooling skills and understanding, an HPT can speed the

remediation process, reduce overall project costs, minimize conflict and

misunderstanding with regulators, promote acceptance and support in the local

community, minimize downtime and back sliding resulting from consultant or

regulatory management turnover, and create relationships and trust between the

utility and regulators that extend beyond any single site characterization and

remediation. The upfront costs of building the team are typically offset by savings

realized later in the project after the team is formed and trust has been built

between the team members.

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In 1994, Pacific Gas and Electric Company (PG&E) initiated the RI/FS/RD/RA

process for three former MGP sites in Chico, Willows, and Marysville, California.

Recognizing the advantages of streamlining the RI/FS process, PG&E combined or

“bundled” the sites into one project. PG&E negotiated one order for the three sites

with California Department of Toxic Substances Control (DTSC) and identified

representatives from PG&E, each of California’s primary regulatory agencies

(DTSC and the Regional Water Quality Control Board), along with a PG&E

consultant to serve as primary case managers for all three sites. In 1996, PG&E

initiated a unique streamlining program, the backbone of which was the Chico/

Willows/Marysville (CWM) HPT.

The CWM HPT, as with most similar teams, was made up of a series of focus

groups or sub-teams formed solely to promote the project’s successful completion.

The organization of the CWM HPT comprised all potential project stakeholders (in

this case, PG&E, state regulatory agencies, and PG&E’s consultant).

The Sponsorship Team was composed of stakeholder representatives with the

authority to “sign on the dotted line.” These included persons in charge of

policymaking and budget authorization. Members of this team included DTSC’s

Site Mitigation Section Chief and PG&E’s vice-president, who oversees all

environmental operations. These are the ultimate “owners” of the project. 
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For the CWM project, a Leadership Team was also formed, consisting of senior

representatives from PG&E and the regulatory agencies. California regulatory

agencies generally experience a frequent turnover in project managers. Involving

senior staff in the HPT process helps ensure continuity of project decisionmaking

and regulatory interpretation despite personnel changes. Representatives on this

team included PG&E’s Director of Site Remediation and DTSC’s Site Mitigation

Unit Chief.

The Management Team of the CWM HPT is composed of persons charged with

actually carrying out the project. Members are PG&E’s consultant and regulatory

project managers. Separate Task Teams were also formed to address specific issues

or problems. For example, Task Teams were formed for community relations and

risk assessment.

The first task of the HPT was its charter. This exercise formed the basis for the

team’s operations. Steps conducted by the HPT during chartering included:

identifying unifying goals, objectives, and measures by which the team could

evaluate whether it was meeting goals; preparing guidelines for meetings and

communications; and identifying the fundamental rules by which the team(s)

would operate. Because several HPT members were not familiar with either the

RI/FS process or MGP sites, education was also required to ensure that all team

members were comfortable with the process and would support decisions. This

education was conducted during workshops where HPT members reviewed the

operational history and historical documents (MGP facility plans, Sanborn maps,

etc.) available for each site. Applicable state and federal regulations and HPT

member expectations were also discussed.

The second HPT task was the development of conceptual models for each site to

ensure that all HPT members had the same view of site physical conditions, source

delineation, transport pathways, and exposure pathways. The team then jointly

initiated the first steps of the FS, identifying all possible remedial technologies and

screening them to form what all team members (including regulatory agencies)

agreed to as a subset of technologies that could be reasonably applied at the three

sites (i.e., ex situ thermal desorption and asphalt batching). At this time, the HPT

identified two key questions that still needed to be resolved and defined the scope

of an additional focused field investigation designed to collect only the data

necessary for the HPT to complete the FS with a high degree of confidence.

As of July 1998, the CWM HPT completed site investigations and was in the

middle of preparing FSs for the three sites. Although the CWM HPT has been

operating for only approximately one year, significant gains (both fiscal and nonfiscal) have been made both on the CWM project and on other PG&E projects with

the same regulatory agency oversight. Specifically, the HPT format has promoted

better communication among the team members and a notable increase in trust

between PG&E and the regulatory agencies. By the completion of the project, the

CWM HPT will have:

 Expedited completion and review of the FS for all three sites. As each step of

the FS process is completed by the HPT, a technical memorandum is prepared
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3-18

and reviewed by the team. When the FS is complete, these memoranda will be

compiled along with an introduction to form the body of the FS. Because each

memorandum is reviewed and approved by the HPT as it is prepared, final

review of the FS will be a formality. 

 Developed an advisory cleanup standard for remediation. This cleanup

standard is developed with the recognition that it is a target that the HPT is

trying to achieve, and that, given the uncertainties inherent in site remediation,

this target may change. The paradigm shift of recognizing the cleanup

standard as a target and not an absolute gives the HPT “permission” to be

flexible in its remediation and to do what is best for the site, most protective of

human health and the environment, and cost and time effective.

 Evaluated a greater array of remedial alternatives and cost savings, by

evaluating remediation at three sites at once, than would have been possible

for each site if taken individually (i.e., taking advantage of cost savings by

negotiating contracts for work at all three sites rather than for each individual

site).

 Promoted management of uncertainty through contingency planning prior to

remediation, and through HPT communication during remediation to allow

for expedited decisionmaking.

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Robert Doss, Director of Site Remediation, Pacific Gas and Electric 

Company, (415) 973-7601

Francis Anderson, California EPA, Department of Toxic Substances Control, 

(916) 255-3733

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In April and May of 1995, PSE&G met with the NJDEP to discuss the potential to

work with the NJDEP SRP to streamline the MGP site remediation program. As

the result of discussions between the two organizations, the NJDEP/PSE&G

Streamlining Team was established with executive sponsors and co-chairs from

each organization. The goals of the Streamlining Team were stated as:

In partnership, NJDEP and PSE&G will identify and evaluate the process of MGP

site investigation and remediation with the objective of streamlining the process.

The Streamlining Team will identify opportunities for improvement, consistency

of approach, and cost effectiveness. The Streamlining Team will develop a model

that will reflect increased cooperation and teamwork between NJDEP and PSE&G

and should provide measurement and oversight of improvement initiatives.

Impediments that exist in achieving the above will be identified with

improvements recommended (NJDEP/PSE&G, 1996).
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The Streamlining Team initially defined major “issues” that are barriers to efficient

and effective site remediation, identifying causes and developing solutions for

each. The solutions were subsequently grouped by relative ease of implementation

and potential for cost and/or time savings. Two basic categories of recommended

solutions resulted:

 Solutions that were within the control and authority of the Streamlining Team

to implement and would result in relatively greater cost or time savings while

ensuring protection of human health and the environment

 Solutions that were beyond the control and authority of the Streamlining Team

to implement but would provide relatively greater cost or time savings while

ensuring protection of human health and the environment

The Streamlining Team then produced detailed implementation plans for the

recommended solutions that were within the control and authority of the team to

implement. Solutions that were beyond the control or authority of the Team were

sent as recommendations to the NJDEP Green & Gold Task Force Site Remediation

Subcommittee. 

Using the detailed implementation plan prepared by the Streamlining Team, it

was estimated that the time for the RI phase could be shortened by 30 percent and

costs for RI work plans could be reduced by approximately 40 percent, that

remedial investigation costs could be reduced by 30 to 50 percent, and that

remedial investigation report approval time could be shortened by 30 percent to 40

percent. 

Solutions included:

 Establish a dedicated NJDEP case team for PSE&G projects to enhance

communications, encourage empowerment, enhance consistency of application

of regulatory requirements, facilitate increased availability of regulatory staff,

and streamline regulatory agency oversight.

 Establish periodic executive level reviews of program initiatives and results.

 Develop standard report “terms and conditions” for all PSE&G sites.

 Establish standard procedures to ensure proper treatment/disposal of wastes

and/or contamination.

 Establish joint cycle time targets for delivery and approval of plans, reports,

and work-related activities.

 Develop a generic RI work plan, including standard operating procedures, to

streamline site-specific work plan preparation and review.

&RQWDFWV

Rich Blackman, Public Service Electric & Gas, (973) 430-8278

Woerner Max, Public Service Electric & Gas, (973) 430-6413

Chris Kanakis, New Jersey Department of Environmental Protection, (609) 633-

1460
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Whether an environmentally distressed MGP site is a long-abandoned brownfield

or is still owned and operated by a public or private utility, remediation can be

expedited by developing an appropriate, beneficial reuse strategy. The remedial

approach can then focus on cleaning the site up to a level acceptable for its future

use (e.g., residential, industrial or commercial). Early land-use determination

usually requires a multi-faceted team (including real estate professionals, land-use

planners, local redevelopment agencies and environmental groups, financial

analysts, community relations specialists, regulators, insurance professionals,

remediation engineers, and others) and depends, ultimately, on the opportunity

for local real estate development. Successful projects have identified a beneficial

use for former MGP sites that increased their asset value and/or offered multiple

other benefits to the local community. This strategy only works when the

economics of the project are adequate to support both remedial cleanup and

development of the site after cleanup. 

The USEPA has recognized that restoring a contaminated property can bring

strength and life to a community. They have defined brownfields as abandoned,

idle, or under-used industrial and commercial facilities where expansion or

redevelopment is complicated by real or perceived environmental contamination.

To promote brownfields redevelopment, the USEPA announced its Brownfields

Action Agenda in January of 1995. This agenda outlined four key areas of action

for returning brownfields to productive use:

 Awarding Brownfields Pilot Grants

 Clarifying liability and cleanup issues

 Building partnerships with all brownfields stakeholders

 Fostering local workforce development and job training initiatives

In May of 1997, the USEPA expanded its Brownfields Initiative by announcing the

Brownfields National Partnership Action Agenda which provided a framework for

cooperation among governments, businesses, and non-governmental

organizations. The Brownfields Partnership addressed all aspects of the

brownfields processes with monetary commitments from federal agencies and

non-governmental organizations. To date, USEPA has funded more than 120

brownfields pilot projects.

A key to the success of the Brownfields program is the clarification of liability and

cleanup issues. To address these issues, USEPA developed guidance promoting

early land-use planning discussions and the use of Prospective Purchasers of

Contaminated Property Agreements under which USEPA agrees not to sue the

buyer of a property for existing contamination. USEPA also developed and issued

policies on:

 The issuance of comfort letters (letters sent to stakeholders who need

information on USEPA’s involvement at potentially contaminated properties)
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 Circumstances under which USEPA will not pursue the owners of property

where groundwater contamination has migrated to their property in instances

where the owner did not contribute to the contamination

 Comprehensive Environmental Response Compensation and Liability Act of

1980 (CERCLA) enforcement against lenders and government entities that

acquire property involuntarily

 The Underground Storage Tank Lender Liability Rule

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The intent of the early land-use strategy is to evaluate a variety of potential land

reuse options (for one site or a portfolio of sites) and to select reuse options that

meet the following criteria:

 Local market need

- Availability of potential developers interested in the reuse option

 Profitable financial analysis

- Financial analysis including cost of remediation and liability management

- Reasonable profit and return on investment

- Insurance products

 Environmental compatibility 

- Regulatory agencies willing to provide “comfort letters” or “covenants not

to sue” after remediation is complete

- Cleanup levels based on reuse approach, limited remediation risks

 Physical feasibility 

 Political acceptability (if local community approval is required)

- Support of community and local government

- Assurance that zoning changes can be achieved for the planned property

use

Typically, real estate reuse specialists evaluate potential reuse options and work

with remedial engineers and regulatory analysts to consider the level of cleanup

and redevelopment necessary for these options. For options with merit, a financial

analysis is developed. The analysis may indicate that the cost of remediation for a

given site exceeds the potential revenue for all reuse options considered. When

this is the case, early land-use determination will no longer be appropriate unless

the owner can include the site within a portfolio of sites that, together, make up a

financially feasible reuse package. There are developers who specialize in

evaluating and purchasing portfolios of environmentally distressed properties.

They evaluate the economics of a portfolio as a whole. If there is sufficient return

on investment from the whole portfolio, the loss associated with individual sites

that cannot be cost effectively redeveloped is acceptable.
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When a site is being considered for a reuse option, the project’s success rests on

acceptance and buy-in of all parties. Once all affected parties accept the reuse

option, a reuse-specific risk-based management plan can be developed and

supported by the regulatory agencies with authority over the project. There is

significant support within the USEPA and many state environmental regulatory

agencies for risk-based approaches to remediation and reuse of historically

contaminated industrial properties. 

Assuming that stakeholders in the property all accept a recommended reuse

option, a development plan and marketing package can be prepared to solicit bids,

or the site owner can choose a specific developer for the entire process. Once the

developer is selected, insurance can also be used to limit the remediation cost and

to specify how remaining or future environmental liability will be apportioned

(Daddario, 1997; Voorhees, 1997; Barnett Alexander, 1997).

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Coal gasification processing occurred from 1853 to 1963 at the Bangor Gas Works,

resulting in widespread coal tar contamination of soil and groundwater at the site.

Large quantities of viscous tar had been stored in on-site underground storage

tanks. The property was eventually abandoned. The City of Bangor purchased the

4-acre property, located in a mixed residential and commercial area, in 1978. After

the purchase, the city discovered an underground tank containing 45,000 gallons

of coal tar as well as other underground contamination consisting of subsurface

pools of coal tar and related substances. Within 1 mile of the site there are

wetlands and the Penobscot River, which supports salmon, rainbow trout, and

spring smelt.

In 1978, the City of Bangor alerted the Maine DEP to the site contamination. The

Maine DEP oversaw initial remedial actions, which included:

 Filling the underground tank with clay

 Demolishing the old gasification buildings

 Paving over the site to create a parking lot

Subsequent investigations confirmed that these actions would prevent the coal tar

from migrating off site.

In 1990, USEPA placed the site on the Comprehensive Environmental Response,

Compensation and Liability Act Information Systems (CERCLIS) list. Maine DEP

accessed Superfund monies and performed a preliminary assessment of the

contamination and a site inspection. The studies concluded that the previous

asphalt paving had adequately reduced the potential for migration or direct

contact with the contaminated soil through an airborne release. In 1994, after the

study results were made public, the City of Bangor, Shaw’s Supermarket, and

Boulos Developers agreed to build a 60,000-square-foot supermarket on the site

and adjacent properties. The project cost was $9.5 million. 
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A partnership was formed between the City of Bangor, USEPA, and Maine DEP to

develop a plan that would permit concurrent cleanup and redevelopment. In 1996,

a multi-layer cap was constructed over the areas where coal tar by-products

remained, so all sources of contamination would be isolated prior to building. The

new supermarket was intended to be the largest in the area and thus would spur

economic expansion and downtown redevelopment (USEPA, 1998a). 

The Bangor gas works site consists of a number of parcels. In addition to the

portion that has been the subject of redevelopment to date, a number of parcels are

still being investigated, and as appropriate, remediated.

Site remediation/redevelopment involved a number of actions to address

contamination. In the 1970s, with Maine DEP approval, 430,000 gallons of coal tar

were removed from the site and burned in a paper mill boiler. Analysis of location,

characteristics, and fate and transport aspects of residual contamination indicated

that further excavation was not warranted at the time. The site currently has a cap

and a passive venting system and is subject to deed restrictions. If conditions

warrant, the passive venting can be converted to active extraction.

&RQWDFWV

Stan Moses, City of Bangor, Department of Economic Development, (207) 945-4400

John Harris, U.S. Environmental Protection Agency, Office of Emergency 

and Remedial Response, (703) 603-9075

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Wisconsin Electric Power Company (WEPCO) historically operated a coal

gasification plant on 11 waterfront acres in downtown Racine, Wisconsin.

Contamination requiring remediation was identified at the site.

Prior to initiating remediation, WEPCO decided to hire a consultant to evaluate

potential reuse options for the site. The consultant performed both a physical and

marketing analysis. The analysis determined that the property had significant

value with potential for a variety of multiple uses that would also assist in

revitalization of the city. The reuse option selected was a waterfront community,

now known as Gaslight Pointe.

Remedial actions conducted on the Racine site prior to redevelopment included

the removal of tar holders and highly contaminated soil. The site was then capped,

and a groundwater extraction and treatment system was installed to address

groundwater contamination. A soil venting and vapor extraction system was also

installed to prevent fume buildup in buildings to be constructed on the site.

Gaslight Pointe now includes a marina, townhouses, a hotel, and retail stores. 

The development team agreed on a divestment to a specific developer/builder.

WEPCO assumed no risk and did not need to invest new capital. The remediation

and regulatory approval process focused on the newly recommended

redevelopment use.
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Gaslight Pointe has been a qualified success. It has resulted in reasonable returns

for Wisconsin Energy Corporation as well as providing a source of new jobs and

tax revenues for the community (Barnett Alexander, 1997). Most importantly, it

has completely transformed a previously blighted property into a significant focal

point in the community.

&RQWDFW

James W. Lingle, Wisconsin Electric Power Company, (414) 221-2156

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Uncertainty is pervasive in the characterization and remediation of all kinds of

contaminated sites, including MGP sites. One approach to managing uncertainty

is the observational method. This method provides a way to determine when

sufficient site characterization data have been collected and involves managing

uncertainties through the identification of reasonable deviations from original

plans if changed conditions materialize, and contingency plans to address these

deviations. The observational approach entails monitoring site conditions during

remediation and implementing contingency plans as needed. Using the

observational method gives the flexibility to modify an RA to address conditions

as they are discovered while still completing the action on time and under budget.

Managing uncertainties when applying one or more remedial technologies at a

manufactured gas plant site requires two important pieces of information:

 The input, process, or environmental variables (e.g., contaminant composition,

temperature, soil structure, moisture content) that affect a remedy’s success

 The values of those variables throughout the implementation of the remedy

For ex situ remedial processes (e.g., thermal desorption, catalytic oxidation), this

information can be obtained with relative ease. Process designers can incorporate

the instrumentation and controls necessary to measure the critical process

variables and perform adjustments to optimize process performance.

In situ remedial processes are more difficult. Unless a site is very small and/or the

process is incredibly adaptive and robust, it is difficult to have all the information

needed about the values of critical process variables (e.g., soil moisture). For

example, the heterogeneity of subsurface soils and the lack of good subsurface

analytical technologies make it virtually impossible to map the values of process

variables throughout a site. With today’s technology, the best achievable result is a

reasonable estimate of the range of these variables.

Scientists and engineers working on subsurface construction problems (e.g.,

foundations, dams, tunnels) have found a way to manage the uncertainties

associated with in situ remediation. Geotechnical engineers have addressed

problems of this nature for decades using the observational method (Peck, 1969).

Karl Terzaghi described the conditions for this application almost 50 years ago:
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“In the engineering for such works as large foundations, tunnels, cuts

and earth dams, a vast amount of effort goes into securing only rough

approximate values for the physical constants that appear in the

equations. Many variables, such as the degree of continuity of important

strata or the pressure conditions of water contained in the soils, remain

unknown. Therefore, the results of computations are not more than

working hypotheses, subject to confirmation or modification during

construction” (quoted by Peck, 1969).

The table on the fofllowing page summarizes the key elements of the

observational approach applied to hazardous waste sites. 

Elements of the Observational Approach

 Explore to establish general conditions

 Assess probable conditions and reasonable deviations

 - Depends on remedial technology

 Design for probable conditions

 - Define remedial end point(s) and how to measure

 - Select design/implementation modification for each potential deviation

 - Select parameters to observe and define how to measure

 - Determine expected values of parameters for remedial

 technology under probable conditions and deviations

 Implement remedial technology

 - Observe parameters and compare to anticipated values

 - Implement preplanned actions if deviations detected

Hazardous waste sites involve uncertain subsurface conditions such as those

found by geotechnical engineers at any site but also entail uncertain chemical and

biological parameters. The principal differences from the traditional linear studydesign-build model and the observational methods are the explicit recognition of

uncertainty, characterization of states of uncertainty via scenario development

(i.e., deviations), monitoring for deviations, and preplanning for contingencies.

This is a management approach with feedback loops and preplanned responses.

The success of the observational approach depends upon the ability to alter a site

investigation and/or remediation in the field based on pre-determined

contingency plans. Therefore, the observational approach is not suitable for sites

where there are no available contingent actions for site conditions within an

allowable response time (e.g., a release of contaminants to the atmosphere that

cannot be detected in time to implement a contingency plan).

During the past eight years, the observational method has been increasingly used

for the remediation of hazardous waste sites because it offers two key benefits:

 The method provides a means to determine when sufficient site

characterization data have been collected.
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 The method makes it possible to continue the project by managing uncertainty

through contingency planning rather than trying to overcome it through

additional study or highly conservative remedial design.

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Background

An operating bulk petroleum products storage and transfer facility, 43 hectares in

size, contained approximately 11 million liters of light non-aqueous phase liquid

(LNAPL) in the vadose zone beneath the site. The LNAPL was composed of

approximately 70 percent gasoline-range hydrocarbons and 30 percent dieselrange hydrocarbons and had been located under the site for approximately 68

years. The hydrogeology underlying the site was composed of discontinuous

alluvial and eolian Pleistocene deposits of sand, silty sands, silts, clayey silts, and

dense clays. Depth to groundwater was approximately 3 to 6 meters below grade,

and a cyclic rising and lowering water table resulted in LNAPL being trapped

below the water table at some locations and perched above the water table at other

locations, depending upon the small-scale subsurface stratigraphy.

During 10 years of site characterization, more than 100 borings and wells were

installed at the site. Based on the information gathered from these borings, 60

product-extraction wells were installed to remediate the site. Numerous

piezometers and groundwater monitoring wells were also installed to monitoring

the performance of the extraction system.

The extraction system installed following the site characterization operated

ineffectively because of the site’s stratigraphic heterogeneities. Some wells in the

system produced LNAPL beyond expectations while other wells extracted

practically no product. After several years of operation, the site owner wanted to

expand the LNAPL removal system to increase overall extraction efficiency, but,

because of the stratigraphic heterogeneities, there was significant uncertainty

regarding how a particular LNAPL removal technology or design would perform

in different portions of the site (Haimann, 1996).

Probable Site Conditions

LNAPL flow in the subsurface occurs in the vadose or unsaturated zone and is

therefore dominated by capillary forces. Capillary forces are, in turn, highly

dependent upon soil type, specifically on pore-throat diameters. Pore-throat

diameters vary substantially among different soil types; in alluvial deposits,

diameters can vary by nearly the scale of the soil particles themselves. In addition,

the soil types above and below LNAPL layer(s) can significantly affect the

efficiency of a removal technology by influencing soil moisture and the ability of

the LNAPL to move within the vadose zone. At this site, a conventional site

remediation approach, where a final remedy with a high likelihood of success is

selected, designed, and implemented, would be unlikely to succeed because of the

small-scale heterogeneities observed in the subsurface. At a site such as this, the

cost and time required to gather sufficient data to fully understand the scale and

location of these heterogeneities could exceed the actual cost for several rounds of
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3-27

remediation. Recognizing that such a conventional approach was not an efficient

use of resources, those managing the site selected the observational approach.

In a phased observational approach, remediation is implemented in distinct

phases, without investigating the entire site, to the extent that sufficiently detailed

information is available to design a site-wide system. In effect, each phase of

remediation occurs simultaneously as a phase of investigation. In this case, the

operation of the system and the response of the subsurface to LNAPL removal

were monitored, and data were collected and used to interpret subsurface

stratigraphic features. These features were then used to update the subsurface

stratigraphic model and to design expansions and/or modifications to the LNAPL

removal system.

Remedial Technology Design and Implementation

The initial phases of the project were focused on portions of the site where

subsurface stratigraphy was understood well enough to design an LNAPL

removal system. The subsurface stratigraphic information used to design this

initial extraction phase had been gathered during the field investigations and

operations of the early LNAPL removal systems. The effectiveness of the initial

extractions was then monitored using subsurface monitoring points located at the

edges of the extraction zone to determine reasonable deviations in the monitoring

parameters (indicating the relative success of the treatment setup). Subsurface

monitoring points included monitoring wells, piezometers, and soil vapor probes,

and the types and locations of the monitoring points were varied depending upon

the LNAPL removal technology implemented at the specific area (e.g., liquids

extraction, vapor extraction, dual-phase extraction, bioslurping). Data collected

and evaluated during monitoring included drawdown, product thickness,

subsurface vacuum pressures, and vapor concentrations.

The results of the first phases of LNAPL extraction were used to select and design

the extraction system for the second phase; the results of the second phase used to

design a third, and so on (Haimann, 1996). Continuous monitoring of data during

remedial implementation allowed for the implementation of preplanned actions

(e.g., increasing number of extraction points) as needed to address site-specific

subsurface conditions and uncertainties.

Conclusion

One of the key benefits of the phased approach was the immediate

implementation of remediation. Early extraction of the LNAPL prevented further

migration from the source. Under a conventional scenario, the elapsed time that

would have been lost during an extended site characterization could have led to

the additional spread of LNAPL and therefore increased remediation costs.

Several other cost savings were realized by implementing the phased

observational approach, including (Haimann, 1996):

 A significant reduction in investigation costs. Combining remediation and

investigation into one field effort reduced the need for multiple mobilizations

and management costs from an extended project schedule.
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3-28

 Savings resulting from a reduction in liabilities. Early and proactive removal of

LNAPL prevented migration in the subsurface and reduced expenses relating

to litigation and additional cleanups from off-site contamination.

A reduction in overall project costs resulting from a shortened project duration.

Combining remediation with investigation reduced the overall number of phases

of field work and reduced the remediation schedule because LNAPL migration

was restricted as a result of early remediation.

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Portland General Electric (PGE) operated a steam-powered electricity generating

plant on a 28-acre site known as the Station L facility between the early 1900s and

1975. The Station L facility is located in Portland, Oregon, on the east bank of the

Willamette River.

As part of a transfer of a portion of the Station L property, PGE initiated an

investigation to identify areas where PCBs might have been released. This

investigation led to the discovery of a historical PCB spill in the Willamette River.

A review of company records showed that a transformer next to the generating

plant had failed in 1971. PGE collected sediment samples to determine the extent

of contamination and found that an approximately 80- by 120-foot area contained

PCB concentrations ranging from non-detect to 286 mg/kg.

During a 2-year period, PGE evaluated different remedial alternatives, submitted

RA plans to the Oregon Department of Environmental Quality (DEQ), and

conducted a limited action to remove near-shore contaminated sediments exposed

during low-flow conditions in the river. In February 1990, DEQ issued a Record of

Decision (ROD) that stated that low-volume, diver-operated, performance-standard dredging was the preferred remedial alternative. The performance standard

in the ROD was to remove, if practical, up to 2 feet of sediment in areas with PCB

concentrations greater than 10 mg/kg. Dredging was to be conducted in a manner

that would minimize sediment resuspension. The ROD provided for dewatering

and disposal of dredged sediments in an approved disposal facility and water

treatment to applicable standards prior to discharge to the Willamette River.

Following dredging, the spill area was to be isolated by placing a 6-foot sand,

gravel, and rock cap over sediments containing PCB concentrations greater than 1

mg/kg; the cap was to be constructed in a way that would also minimize sediment

resuspension (Brown, 1988).

Early in the remedial design, it was recognized that a conventional engineering

approach could not be used because the following were highly uncertain:

 Sediment characteristics

 Dredging equipment flow rates required for removing two feet of sediment

 The amount of sediment resuspension associated with low-volume, diveroperated dredging
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 Water treatment system flow rate and influent sediment and PCB

concentrations

 The amount of sediment resuspension associated with cap construction

methods

To manage these uncertainties and meet an the extremely tight project schedule,

the observational method was selected.

The observational method was used to manage virtually all areas of uncertainty.

The most likely outcome, based on available site characterization data and

previous diving contractor experience, was that the suction created by the lowvolume, diver-operated dredge would be sufficient to contain any resuspended

sediment. Further, it was assumed that the suction action of the dredge would

prevent PCB concentrations downstream from the site from rising above the acute

aquatic criterion. A reasonable deviation was that dredging would cause

conditions that exceeded the acute aquatic criterion for PCBs.

The parameter selected for observation was turbidity because it could be

measured in the field in time to implement a contingency plan if a deviation was

detected. Direct measurement of PCB concentrations was not selected because

sample results could not be obtained in time to implement a contingency plan. To

satisfy DEQ's concern for aquatic protection, a correlation between turbidity and

PCB concentration in water was developed before dredging was initiated. This

correlation was developed by relating suspended sediment concentrations (using

site-specific sediments) to turbidity, on the basis of the average PCB concentration

in sediments at the site.

Potential contingency plans included increasing the dredge flow rate to increase

the capture of resuspended sediments, modifying diver operations to reduce

sediment resuspension, and, if neither of these plans worked, stopping dredging

and construction of the sand, gravel, and rock cap.

Monitoring conducted during dredging demonstrated that the turbidity did not

increase downstream of the site and the acute aquatic criterion was not exceeded.

Because no deviation was observed, none of the contingency plans was

implemented (Brown, 1988).

Conclusion

The observational method made it possible to implement a relatively innovative

RA and still complete the project on time and under budget. During a 4-week

period, 22 tons of sediment were removed and more than 500,000 gallons of water

were treated. The average depth of sediment removal was 1 foot. PCB

concentrations were reduced from an average of 12 mg/kg before dredging to

7 mg/kg after dredging. All of this work was conducted without any observable

increase in turbidity, without exceeding the acute aquatic criterion for PCB, and

without any contractor change orders. PGE, DEQ, and the contractor considered

the project a success (Brown, 1988).
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Dennis M. Norton, Manager, Environmental Services, Portland General Electric,

(503) 464-8522

6


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The traditional RI/FS process, as commonly practiced during the 1980s and early

1990s, is a phased approach. It consists of an RI requiring iterations of work plan

preparation, review, and approval; field work; and report preparation, review, and

approval. These steps are all designed to characterize the horizontal and vertical

extent of contamination at a site. This phased RI is then followed by the FS to

determine an appropriate remedial scenario and often includes additional phases

of field investigation to acquire additional data. Following the NCP regulations,

the FS leads to preparation of a Remedial Action Plan (RAP) and RD, culminating

in the actual RA, which often uncovers unexpected conditions and/or

contamination, sending the whole process spiraling back to supplemental RIs and

revised FSs. The result is lengthy and costly site investigation/remediation cycles. 

Changing regulatory and economic environments requires new strategies to meet

the same needs. Private and public entities must now meet environmental

responsibilities in a time of tightening budgets and greater pressure to work in a

faster and cheaper manner. Thus, processes are being developed to expedite the

way RI/FS/RD/RAs are being conducted.

Expedited site characterization and closure involves a number of tools, strategies,

and processes that interlink and synergistically help streamline investigation and

remediation processes. Components of an expedited site characterization and

closure can include the following:

 On-site or rapid decision-making capabilities

 Use of field sampling and analysis tools (such as mobile laboratories and field

screening methods) to facilitate real-time data collection and interpretation

 Use of nonintrusive or minimally intrusive geophysical and/or sample

techniques

 Communication and cooperation among responsible parties, regulatory

agencies, and third-party stakeholders through mediation, facilitation, and

HPTs

 Flexibility in the overall site characterization and remediation processes (e.g.,

setting flexible DQOs)

 Active management of uncertainties regarding the location of former MGP

residues and their effects on remediation costs and technologies, through

modeling and contingency planning

 A streamlined document preparation and review process
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3-31

 A process for reducing team member turnover and minimizing the effects of

team member replacement

Not all components may be necessary to expedite site characterization. Selections

of those component most directly applicable to a site or set of sites can still yield

cost and time savings.

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In 1994, Argonne National Laboratory developed an innovative, cost- and timeeffective process for preremedial site characterization. The Expedited Site

Characterization (ESC) process was developed to optimize site characterization

field activities. 

The Argonne ESC process:

 Is a process and not a single or specific technology or tool.

 Is flexible and neither site- nor contaminant-dependent.

 Demands the highest levels of accuracy.

 Is scientifically driven within a regulatory framework (i.e., regulatory guidance

does not drive the program without science).

 Requires that all field activities potentially affecting the quality of results be

addressed in a quality assurance and quality control (QA/QC) plan.

The basic steps of the Argonne ESC are:

Step 1: A team is formed, composed of an experienced technical manager with a

broad base of experience and a team of scientists (including geologists,

geochemists, hydrogeologists, biologists, health and safety personnel,

computer scientists, etc.) with diverse expertise and strong field

experience.

Step 2: The technical team critically reviews and interprets existing data for the

site and its contaminants to determine which data sets are technically valid

and can be used in initial design of the field program.

Step 3: After assembling and interpreting the existing data for the site, the

technical team visits the site to identify the site characteristics that may

prohibit or call for any particular technological approach.

Step 4: After the field visit, the team selects a suite of technologies appropriate to

the problem and completes the design of the field program. Nonintrusive

and minimally intrusive technologies are emphasized to minimize risk to

the environment and public health.

Step 5: A dynamic work plan is prepared, outlining the technical program to be

followed. The work plan must allow flexibility; therefore the HASP and

QA/QC plan must encompass a broad range of possible work plan

alterations.
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Step 6: The team implements the field program. Data are collected, reduced, and

interpreted each day. At the end of each day, the team meets, reviews

results, and modifies the next day’s program as necessary to optimize

activities that generate overlapping or confirming site details.

Step 7: Daily results and modifications are transmitted to the project sponsor and

regulators, allowing both to participate in early data review and

decisionmaking for the site.

The ESC is an iterative process that optimizes field activities to produce a highquality technical result in a time- and cost-effective manner. Because both on-site

analytical and multiple hydrogeologic techniques are used, there is very little need

to send nearly all samples off-site and to perform massive subsurface sampling in

the absence of local hydrogeologic information. By including on-site

decisionmaking, the ESC process can significantly reduce the probability of having

to return to the site to fill data gaps. As a result, the current multiphase sequence

of environmental data acquisition becomes compressed into a single real-time

phase typically requiring only months to complete (Burton, 1994).

The Argonne ESC process is not the ideal process for all sites. However, the basic

components of the ESC have been applied at other former MGP sites to expedite

site characterization and remediation. These basic components are also included in

the American Society for Testing and Materials’ (ASTM) provisional standard

guide for Accelerated Site Characterization for Confirmed and Suspected

Petroleum Releases (PS 3-95) (ASTM, 1996). Although the types of contaminants

found at former MGP sites are typically more complicated than those found at

sites with only petroleum releases, the general process published by ASTM in their

provisional standard guide is similar to that outlined for Argonne’s ESC program.

Both published programs involve review of existing site information and

development of a conceptual model prior to sample collection, followed by an

on-site iterative process designed to collect, analyze, and interpret all data in a

single field program.

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In 1994 and 1995, USEPA’s Ames Laboratory adopted the Argonne National

Laboratory’s ESC process for demonstration at the Marshalltown former MGP site

in Marshalltown, Iowa. The Marshalltown former MGP site was owned by IES

Utilities, Inc., and was located in an old industrial area adjacent to an active

railroad switching yard and main lines. Gas manufacturing operations occurred

between the 1880s and 1950s, resulting in the release of a variety of MGP wastes,

including coal tar, petroleum hydrocarbons, condensates, and oxides.

Before the ESC at the Marshalltown site, five rounds of field investigation and/or

reporting had been conducted. Data collected during these investigations

provided the historical and technical information necessary to select technologies

and develop scopes of work for the ESC demonstration.
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The ESC methodology applied at the Marshalltown former MGP site incorporated

on-site decision-support technologies that enabled site characterizations to be

completed in a consolidated package. 

The principal characteristics of the Ames ESC were:

 Emphasis on geologic structure and hydrogeology to determine contaminant

fate and transport

 Use of technologies by expert operators with flexible data quality objectives

 On-site data processing using mobile laboratories

 On-site decisionmaking

 Preference for nonintrusive or minimally intrusive geophysical techniques

 Minimization of intrusive sampling techniques

 A single team for planning and managing site work

The use of minimally intrusive survey techniques, on-site analytical technologies,

and innovative sampling and screening technologies (such as the Site

Characterization and Analysis Penetrometer System cone penetrometer unit and

GeoProbeTM soil conductivity probe) to determine the local hydrogeologic setting,

supported the potential for significant time and cost savings. For example,

geophysical survey techniques including ground-penetrating radar, seismic

reflection and refraction, electromagnetic offset logging, and borehole logging

were applied at the site to define the surface of the bedrock and significant

stratigraphic interfaces above the bedrock and to provide information regarding

the distribution of PAH contamination (Bevolo, 1996). By including on-site

decisionmaking, the Ames ESC process significantly reduced the number of

iterations of field investigations that otherwise would have been necessary to fill

data gaps. As a result, the typical cycles of work planning, field investigation, and

reporting, which often take years to complete, were compressed into months. 

Site Characterization 

The Site Characterization and Analysis Penetrometer System (SCAPS) cone

penetrometer unit, GeoProbeTM soil conductivity probe, and geophysical survey

technologies provided very useful and reliable stratigraphic data. Side-by-side

comparisons of the direct-push technology logs with previous investigation

borehole logs indicated stratigraphic correspondence to within about 1 to 2 feet. It

should be noted, however, that the previous data tended to provide a slightly

deeper granular/lower cohesive unit contact than direct-push data. Usually, the

major unit stratigraphic contacts were easily picked off of both the cone

penetrometer testing (CPT) and soil conductivity logs, and were used to create a

database from which a three-dimensional site stratigraphic model was generated.

Based on previous site characterization work, the lateral and vertical distribution

of the dissolved PAHs and residual NAPL contamination was estimated.

Assessment of the nature and distribution of the PAH contaminants was carried

out using three types of technologies: Phase I screening technologies
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(immunoassays, passive and active soil gas, and chemiluminescence), Phase II

screening technologies (laser-induced fluorescence probe, soil conductivity probe),

and Phase II quantitative technologies (chemical analysis of soil samples with gas

chromatography mass spectrometry instruments in field laboratories).

The Phase I contaminant screening technologies were applied in an effort to

evaluate their ability to identify the approximate boundaries of the contaminated

area. Duplicate soil samples were collected from different depths and analyzed

using three different immunoassay techniques and the chemiluminescence system.

In addition, passive and active soil gas samples were collected and analyzed from

the approximate depths of the soil samples.

The presence or absence of detectable PAHs and the data from each of the three

immunoassay analyses correlated fairly well with each other. Results from the

chemiluminescence did not correlate as well. Active soil gas measurements for

aromatic hydrocarbons and naphthalene showed good agreement with passive

soil gas and immunoassay measurements. Overall, the results of the Phase I

contaminant screening technologies generally compared well with the previous

investigation results. One significant finding of the screening was that PAH

contamination existed farther to the west than appeared from previous data.

Phase II contaminant screening was performed using the cone penetrometer laserinduced fluorescence (LIF) sensor system and the GeoProbeTM soil conductivity

profiles. Chemical analysis of soil samples collected adjacent to LIF “hits”

indicated that although the LIF sensor data could not be considered quantitative, it

could reliably detect regions of low, medium, or high contamination. The LIF may

be considered the most direct qualitative methodology for indicating regions of

PAH contamination.

Phase II quantitative plume delineation efforts were planned and implemented

based on results of previous investigations, Phase I and Phase II screening, and an

updated site geologic model. The primary technology evaluation function of this

part of Phase II was the comparison and assessment of five on-site extraction

methods for PAHs in soil (sonication, microscale, microwave-enhanced extraction,

thermal desorption, and supercritical fluid extraction).

Conclusion

A significant finding of the study was the potential for inconsistencies in

procedures and results even with strict adherence to SW846 methods. The

application, versatility, and high quality of data from direct-push technologies

were demonstrated at the site. 

The study also indicated the potential for significant variation of chemical analysis

results for PAHs in soils. The uncertainty and potential variability associated with

soil matrix effects, sample selection, and preparation and extraction procedures far

outweigh inaccuracies in the chemical analysis methodologies themselves. The

Phase I and Phase II screening results, including olfactory and visual data, gave a

far better picture of the distribution and extent of contamination than the

quantitative analysis results.
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The Ames ESC team implemented the ESC model using many of the tools that are

essential to ESC, such as a dynamic work plan real-time data analysis and

incorporation of stakeholders in the decisionmaking process. Establishing and

maintaining close communications with the regulators was viewed as critically

important, and significant efforts were made to invite participation from

stakeholder groups including local residents, community organizations, educators,

students, trade press, local media, etc. (Bevolo, 1996).

&RQWDFWV

Dr. Al Bevolo, Ames Laboratory, Iowa State University, (515) 294-5992

Bruce Greer, Alliant Energy, (608) 252-3948

Johanshir Golchin, Iowa Department of Natural Resources, (515) 281-8925

3DFLILF *DV DQG (OHFWULF &RPSDQ\ &KLFR:LOORZV0DU\VYLOOH )RUPHU 0*3V

In 1994, Pacific Gas and Electric Company (PG&E) initiated the RI/FS/RD/RA

process for three of its former MGP sites where Preliminary Endangerment

Assessments (PEAs) had been completed in 1991. PG&E chose the former MGP

sites in Chico, Willows, and Marysville, California, because they had similar

operating histories and MGP-related contaminants, similar geologic settings, and

were in close geographic proximity. Recognizing the advantages of streamlining

the RI/FS process, PG&E initially combined or “bundled” the sites into one

project, negotiating one order for the three sites with the California EPA

Department of Toxic Substances Control (DTSC). Representatives from PG&E and

its consultant as well as the state’s primary regulatory agencies (DTSC and the

Regional Water Quality Control Board) were identified to serve as primary case

managers for all three sites. In 1996, an alternative, streamlined approach to the

RI/FS was proposed and adopted in addition to the site bundling implemented

earlier.

Streamlining the RI

By bundling three sites into one “package,” PG&E observed immediate cost

savings from reducing the volume of paper documentation and negotiating lower

unit pricing as a result of larger volumes of laboratory analyses and work than

would have applied to a single site. Further cost savings were achieved by

negotiating one order with regulatory agencies and incurring oversight costs for

only one regulatory agency caseworker for all three sites and by preparing one

HASP and one RI work plan for the three sites. This work plan outlined the field

sampling protocols and described the decision process by which field crews

would identify and justify field sampling locations. These protocols were then

used along with a field sampling flowchart in lieu of figures identifying specific

locations for sampling. Such predetermined processes for decisionmaking and

communications enabled the team to actively manage uncertainty about the extent

of onsite contamination. Therefore, the number of field investigations required to

adequately characterize the sites was significantly reduced.
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The RI field programs developed for the three former MGP sites were further

tailored so that field crews went from site to site (Willows and Chico are 45

minutes apart by automobile; Chico and Marysville are approximately one hour

apart), circling back after well seals had cured and wells could be developed and

sampled. Thus, well development and sampling took place in a short time. As part

of the streamlined field program, lower unit pricing was negotiated with

subcontractors (drilling and analytical laboratory) by offering larger volumes of

work than would have been the case for a single site. Field personnel used in situ

samplers (e.g., HydropunchTM and SimulprobeTM samplers) and field screening

tools (Handby colorimetric kits and PetrosenseTM probes) to further aid in field

evaluations of the extent of contamination. Through site bundling and field

decisionmaking (aided by in situ and field screening tools), PG&E saved an

estimated $120,000 during the preliminary phase of the RI/FS alone.

Streamlining the FS

As the Chico/Willows/Marysville (CWM) project continued into the FS stage, the

project team adopted additional measures to streamline the project. The backbone

of these measures was the formation of an HPT, discussed previously in greater

detail in Section 3.2.4.

Significant gains have been made to date as a result of the streamlining at the

CWM sites. Expenditures have been decreased by bundling of sites and by

allowing flexibility to modify field programs during implementation. This

flexibility has reduced the number of phases of field sampling required to

determine the extent of contamination. In addition, both the CWM project and

other PG&E projects with the same regulatory agency oversight have benefitted

from the improved communication and trust between PG&E and the regulatory

agencies as a result of the HPT’s work.

&RQWDFW

Robert C. Doss, Pacific Gas and Electric Company, (415) 973-7601

7-4
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Recognition of the need to change the RI/FS/RD/RA process is not limited to

consultants and private organizations; regulatory agencies have also seen the need

to streamline site characterization and remediation. Legislative innovations have

created a range of programs for regulatory agencies to streamline site

remediations in the hope of significantly lessening current and future threats to

human health and the environment in a much shorter time period than possible

using the traditional RI/FS/RD/RA process. An example is the pilot Expedited

Remedial Action Program currently being implemented by the State of California.

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The California Expedited Remedial Action Program (ERAP) was established under

the authority of the Expedited Remedial Action Reform Act of 1994. Its purpose is

to test alternative regulatory policies for the remediation of contaminated

properties by providing for a comprehensive program that includes revised
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liability based on fair and equitable standards, indemnification protection through

a covenant not to sue, risk-based cleanups based on the ultimate use of sites,

streamlined remediation processes, and a dispute resolution process. Because sites

involved in the ERAP process follow the California Uniform Agency Review

Hazardous Materials Release Sites (California Health and Safety Code Division 20,

Chapter 6.65), permits and certification are issued through one lead oversight

agency, which minimizes duplicate efforts among regulatory agencies

(Cambridge, 1998).

Only 30 sites may participate in the pilot project; participation is voluntary by

responsible parties (RPs) for sites. Participants must agree to pay for all oversight

costs not paid by another RP or the trust fund designated for “orphan shares;”

response costs apportioned to parties that cannot be located, identified, or are

insolvent are considered orphan shares. If monies are available in the trust fund

established for ERAP, these are refunded to the RPs once a site is certified. Only 10

sites in the pilot program may be designated as orphan share sites (Cambridge,

1998).

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In Alhambra, California, Southern California Gas Company (SoCal Gas) elected to

participate in the California EPA DTSC and ERAP to expedite cleanup of the

Alhambra MGP site.

Site Background

SoCal Gas entered into a Remedial Action Consent Order with the DTSC on May

5, 1994, to perform remedial investigations at the Alhambra MGP. On September

22, 1995, SoCal Gas submitted to DTSC a Notice of Intent to have the site

participate in ERAP. The site was admitted into ERAP on November 27, 1995, and

thus was no longer subject to the Remedial Action Consent Order. In March 1996,

DTSC and SoCal Gas signed an Enforceable Agreement for performing a site

investigation and remediation. DTSC became the lead agency for the site cleanup.

The site consists of 20 residential lots on 2.4 acres. An MGP operated at the site

from 1906 to 1913. SoCal Gas acquired the property, which had had two previous

owners, in March 1939 after the gas plant had been dismantled, and sold the

property to an individual in September 1939. This owner then subdivided the

property and sold the lots for residential development beginning in 1940.

Investigations prior to the site’s inclusion in ERAP had shown MGP

residues—arsenic, lead, and cPAHs—might be present in on-site soils at levels that

would exceed risk-based soil concentration goals. Therefore, a site inspection was

conducted after the site’s admission into ERAP.

The SI concluded that there was significant, widespread contamination in soils at

the site. The level of contamination required excavation and removal to eliminate

threats to public health and the environment. The SI also determined that

groundwater had not been affected by MGP wastes.
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The RA goal for the Alhambra site was to restore the levels of chemical exposure

to background conditions. Values were established using a statistical evaluation of

a background data set, which consisted of 184 samples collected over 20 different

locations in Southern California. The remedial action plan (RAP) proposed the

excavation and removal of all contaminated soil from the front and backyards of

18 of the 20 homes located on-site. The RAP also proposed removing all

contaminated soil in the crawlspaces underneath each home. 

A number of public meetings and other community outreach efforts were

undertaken. The site’s residential community was multicultural, with the

languages spoken among 20 property owners including English, Spanish,

Vietnamese, Cantonese, and Mandarin. All fact sheets and public notices were

translated into those languages. At the public meeting for the RAP, four

translators were present to address questions from the audience. All one-on-one

meetings held between on-site residents and DTSC and SoCal Gas representatives

had an interpreter present, if needed.

The final RA for the site began on July 23, 1997. The excavation portion of the

project was done in phases. Four families would be relocated at a time, and

excavation and removal activities would focus on those four properties. A

relocation company handled details of moving residents. After completion of

excavation activities at each house, backfilling and restoration activities included

replacement of all landscaping and hardscaping removed as a result of the

remedial activities. Remedial activities at the site were completed on February 13,

1998. The total volume of contaminated soil removed was 9,000 tons. DTSC issued

a certificate of completion to SoCal Gas on February 27, 1998. The site evaluation

and cleanup under ERAP took just over two years.

Benefits of ERAP

Sites posing the greatest public health or environmental threat are the highest

priority for remediation. The Alhambra property was a natural priority because

the presence of on-site residents created a high probability of direct exposure.

SoCal Gas had reservations about proceeding with remediation in view of

uncertainties about the requirements and effectiveness of the cleanup, the

interruption to residents’ lives, the possible liability resulting from cleanup, and

the time and cost involved. The ERAP pilot project provided some assurance that

the cleanup would be efficient and made explicit the potential risks and liabilities

of remediation. SoCal Gas viewed the most beneficial aspects of ERAP as:

 “Lead” Agency Designation—DTSC, as lead agency, communicated with the

other state and local agencies involved with the site. Contacts occurred early,

during the preparation of the application package for the program. At this

stage, DTSC contacted each affected agency to determine its concerns and

anticipated level of involvement so these could be incorporated up front. Once

the site was selected, DTSC invited these agencies to participate in the site

conference that was required within 90 days of site designation. This provided

other agencies with an opportunity to raise issues that could then be

incorporated into work plans. Once site remediation was completed, DTSC

issued a certificate of completion, which provides regulatory clearance from all
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3-39

other state and local agencies regarding hazardous substances issues. This

certificate indicates that SoCal Gas’s remediation of the site is complete.

 Guidelines for Public Participation and Involvement— ERAP provides that

the party responsible for a site must comply with DTSC’s public participation

manual. Public participation was essential to the success of this project. In

addition to fact sheets and an information repository, many public meetings,

both formal and informal, were conducted to facilitate ongoing discussions.

Most notable were the one-on-one discussions with residents. These contacts

meant that the project managers considered residents’ perspectives when

making decisions, such as what types of trees or grass to replant during the

landscaping activities and the timing of each activity. The result of the public

participation efforts was positive community response to the cleanup.

 Risk-Based Decisionmaking—Any remedial action proposed by an RP must

leave a site in a condition appropriate to its planned use without any

significant risk to human health or the environment. Under ERAP, RPs are

provided flexibility when selecting the remedial action; the DTSC does not

give special preference to any particular actions. Evaluation of the remedial

actions is based on their individual merit in light of site-specific conditions.

Although this provision is most applicable to sites that will be used for

commercial or industrial purposes, SoCal Gas demonstrated it could be

applied to residential sites.

 Apportionment of Liability Based on Fair and Equitable Principles and

Orphan Share Funding —The process for apportioning liability among parties

potentially responsible for a site (e.g., previous and current owners) involves

assigning to each a percentage of liability for necessary remedial action at a

site. As an alternative to liability determination through judicial process (cost

recovery under CERCLA), ERAP provides for DTSC to apportion liability to

each RP. For this site, SoCal Gas was able to recover some cleanup costs

through DTSC’s apportionment of liability to orphan shares.

 Indemnification through a Covenant Not to Sue — Within the ERAP

enforceable agreement is a requirement for a covenant not to sue under

CERCLA between DTSC and the RPs who are signatories to the agreement.

This covenant is conditional on performance of all obligations of CERCLA and

the conditions outlined in the enforceable agreement. This covenant becomes

effective upon completion of the RAP and receipt of the certificate of

completion. Because the certificate of completion for the site is issued under

the provisions of the Unified Agency Review Law, the RP can qualify for

immunity and protection from future liability. However, the covenant not to

sue does not apply to natural resource damage claims filed pursuant to

CERCLA. SoCal Gas valued the protections afforded by this covenant, which

significantly reduced the risk of future claims being made against the company

because of the Alhambra site. The ERAP process also provides assurance that

other agencies will not take additional enforcement actions in the future.

Conclusion

The Alhambra former MGP site is an example of a site remediated after a
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residential community was established there. Because residents live on-site, direct

exposure to MGP residues was the greatest health risk. The focus of the project

was to restore the site to background exposure levels and return the residents to

their homes in the shortest amount of time with the least amount of disruption. Of

most importance to SoCal Gas was the definition of the time and costs associated

with the project and the determination of the company’s liability. The ERAP

program provided SoCal Gas with assurances regarding risks as well as monetary

relief from the ERAP trust fund, which will reimburse costs assigned to orphan

shares.

&RQWDFW

Megan Cambridge and Adam Palmer, California EPA DTSC, (916) 255-3773

8*
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Combining remediation strategies with business decisions can, when the

circumstances are appropriate, provide additional opportunities for significant

savings in total remedial cost, the effort required to secure permits, or time

required to complete the project. The greatest cost and time savings are realized

when remediation, land use/reuse, and business considerations can be aligned. 

Depending on factors such as the numbers of MGP sites requiring remediation in a

given area and the types of wastes involved, a number of business strategies may

make sense. Parties responsible for one or more MGP sites may want to consider

options such as: entering into a business venture with a local facility that could

treat the MGP wastes; purchasing rather than renting remediation equipment;

developing an affiliate company that markets cleaned and treated soil and/or

provides cleanup services to others after MGP site remediation is complete; or

undertaking a joint venture to create a mobile or fixed treatment facility. These

options may offer significant savings in total time and cost of a remediation

project.

The following list of questions is designed to help determine whether undertaking

a remediation business venture might expedite and reduce the long-term costs of

remediation:

(1) Are there multiple MGP sites in close proximity that have large volumes of

contaminated materials that could be treated using the same remediation

technology? (The sites may have multiple owners as long as they have

similar wastes.)

(2) Are there other sites in the area with large volumes of similar waste that

could also be treated with this remediation technology?

(3) Are there local political, community, and land reuse/redevelopment

conditions that would predispose regulators to approve a remediation

approach targeting multiple sites?
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(4) What are the actual contaminants and their concentration levels? 

(5) Do these contaminants lend themselves to off-site remedial treatment that

would meet regulatory cleanup criteria? (e.g., non-hazardous vs. hazardous)

(6) Are there conveniently located facilities that could accept the contaminated

material as supplemental fuel for blending? Examples include utility boilers,

cement kilns, and asphalt batching facilities. Alternatively, is there a local

waste treatment facility that could treat these wastes or incorporate a

process to do so? If so, could this facility readily expand its permit to

incorporate the new treatment process? Does this facility have adequate

room to add such a treatment process?

(7) Has the local state environmental regulatory agency approved a permit for

the treatment approach of interest in the past?

(8) Is there a regulatory process in place that would allow testing and

approving the treatment process for the MGP application?

(9) Is the local operating facility or disposal/treatment company willing to

assume financial and other risks in exchange for a guarantee to be given a

specific amount of material for treatment?

(10) If there is no local facility in a position to accept the wastes in question,

what are the economics of purchasing rather than renting remediation

equipment (e.g., thermal desorbers, asphalt batchers)? This analysis should

take into consideration the long-term costs of treating all MGP sites for

which the party in question is responsible.

(11) Is there a market for cleaned or treated soil from the site(s) (e.g., for clean

fill, asphalt, etc.)?

(12) Is there a market at other sites for the same remediation services required at

the MGP site(s)? 

(13) Are there local operating facilities or disposal treatment companies that are

entrepreneurially oriented and willing to assume financial and other risks in

exchange for a guaranteed volume of material for treatment?

Reviewing the answers to these questions can help clarify the opportunities to

combine remediation efforts for several sites and/or to undertake new business

efforts that can continue after remediation of a company’s own sites is complete.

Opportunities for off-site remedial treatment at fixed treatment facilities are ideal

because the process of obtaining environmental permits is simplified if the waste

materials are treated at one location. In addition, a fixed facility can draw input

(contaminated materials) from a larger area and operate more efficiently than a

mobile facility, thereby offering its customers a unit cost reduction borne from the

economics of scale. However, it is also possible to form successful business

ventures to treat wastes using mobile facilities at multiple sites. 

Remediation business ventures are most promising in a geographical area where

there has been considerable past utility/industrial activity, so large quantities of

contaminated materials requiring remediation are likely to be present. Such areas
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are likely to already have waste or hazardous waste treatment/disposal facilities,

co-burning boilers, cement kilns, and/or asphalt batch plants nearby with whom

joint ventures can be undertaken. If off-site (fixed) treatment facilities are not

readily accessible, however, there is the possibility of purchasing treatment

equipment, developing a mobile facility or entering into a business agreement to

construct an off-site facility. The success of a project like this often hinges on the

local regulatory agency’s willingness to consider such ventures. Whenever there is

a local need for redevelopment of several contaminated sites, the area’s long-term

cleanup needs can be used as an argument to support a proposal for a remediation

business venture. 

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Several related case examples are provided for co-burning (Section 5.2.1) and

asphalt batching (Section 5.2.3).

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A New Jersey utility owned multiple MGP sites contaminated with typical MGP

wastes. Ten of these sites were scheduled for eventual remediation. In considering

options to reduce overall remediation costs, the utility evaluated its business

options in light of the upcoming remediations. Because the company owned

multiple sites with large volumes of contaminated soil, it sought options that

would take advantage of economies of scale during remediation. The utility also

hoped to return treated soil to the original sites. 

In response to the utility’s need, two environmental service companies, Casie

Protank and American Eco Corporation, formed Mid Atlantic Recycling

Technologies Inc. (MART). (Casie Protank owns and operates a waste

transportation, transfer, and treatment facility in New Jersey. American Eco

Corporation provides environmental, construction, and industrial services.) The

utility and its remediation contractor negotiated a 5-year agreement with MART

that committed MART to providing financing and then constructing and

operating a thermal desorption facility specifically to treat MGP-contaminated

soil. The facility is located in Vineland, New Jersey. The intent was that the

thermal desorber would also be able to remediate other soils, specifically those

contaminated with total petroleum hydrocarbons (TPHs). Construction of the

facility cost $9 million and took 7 months; it began accepting MGP soils in July,

1997. 

The NJDEP approved a permit for the facility’s Astec/SPI low-temperature

thermal desorber, requiring it to process contaminated soil to meet risk-based

Residential Direct Contact Soil Cleanup Criteria. The desorber system can treat up

to 45 metric tons/hour and reaches a treatment temperature of 540( C. After

treatment, the soil is analyzed to demonstrate that Residential Direct Contact Soil

Cleanup Criteria have been met. The treated soil can then either be returned to the

generator or kept on-site and reused.

The first MGP site remediation undertaken by the utility was in an urban area. The

site was vacant. Local community leaders wanted to see it converted to a new

office complex. The project started in July, 1997, and was completed in 16 weeks.
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Although 27,000 metric tons of soil and debris were transported to MART for

remediation and the former MGP site is in a high-traffic area, the project did not

disrupt local traffic or create an environmental or health hazard. The desorption

treatment approach was successful; on the first pass all treated materials met the

cleanup criteria specified by NJDEP. Treated soil was returned to the site, and the

land was turned over to the community for beneficial use after treatment was

complete and the site had been seeded (DiAngelo, 1998).

&RQWDFW

Brian Horne, Mid Atlantic Recycling Technologies Inc., Vineland, New Jersey,

(609) 696-3435

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PAHs are a by-product of the incomplete combustion of organic material, and are

found in everything from grilled meats to waste oil to MGP wastes. In today’s

society, the incomplete combustion of fossil fuels from heating systems,

automobile exhausts, garbage incineration, crude oil processing, and many other

practices release PAHs into the atmosphere where they tend to adhere to particles

in suspension. Some of these suspended particles ultimately fall back on surface

soils or aquatic environments. Establishing the background concentration of PAHs

at MGP sites is therefore a significant challenge because it is necessary to

distinguish the proportion of PAHs that come from MGP site wastes from those

produced elsewhere.

In risk assessment, sample concentrations from a site are compared to background

concentrations to identify non-site-related chemicals that are found at or near a

site. If background risk is a possible concern, it is typically calculated separately in

order to accurately evaluate the additional risk to public health or the environment

posed by contaminants from a site. According to the Risk Assessment Guidance

for Superfund (RAGS), (USEPA, 1989) information collected during a site

characterization can be used to screen for two types of background chemicals: 

naturally occurring chemicals (i.e., those that have not been influenced by

humans) and anthropogenic chemicals (i.e., those that are present because of

human activity).

However, RAGS goes on to recommend that anthropogenic background chemicals

not be eliminated from risk calculations as it is typically difficult to show that the

chemicals are present at the site because of operations not related to the site or

surrounding area. This presents a dilemma to those remediating MGP sites located

in urban areas as the risks associated with background PAH concentrations are

often quantified at concentrations above the incremental cancer risk of 10 -4 to 10 -6,

the criterion the USEPA most often uses for site restoration.

An alternative to the development of RA objectives based on traditional risk

assessment practices is the establishment of background levels of anthropogenic

materials and the application of those levels as a standard for site cleanup. This

methodology has been applied at MGP sites and is gaining more acceptance as the
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cost and difficulty of cleaning up to pristine levels, sometimes beyond background

concentrations, becomes clear.

Relatively few studies have been published in which PAH concentrations in soil

have been quantified. According to one review of literature published in the

Journal of Environmental Quality (Edwards, 1983), typical concentrations of

benzo(a)pyrene (a known cPAH) in soils of the world range from 100 to 1,000

micrograms per kilogram (μg/kg). A typical range for total PAHs was about 10

times the value for benzo(a)pyrene alone, with the actual measured concentration

of benzo(a)pyrene ranging from 0.4 μg/kg in remote regions to 650,000 μg/kg in

very highly polluted areas. A second study on the background concentrations of

PAHs in New England urban soils (Bradley, 1994) determined that the upper 95

percent confidence interval on the mean was 3 mg/kg for benzo(a)pyrene toxic

equivalents, 12 mg/kg for total potentially cPAHs, and 25 mg/kg for total PAHs.

The lack of adequate studies on background concentrations of PAHs, along with

the need for site-specific information, indicates the demand for the development

of a standardized procedure for establishing background PAH concentrations,

rather than a single numerical value against which all other PAH values are

measured.

A primary consideration in characterizing background levels of anthropogenic

materials is the establishment of what constitutes background. In some cases,

background has been functionally defined. For example, at CERCLA sites,

background is defined as off-site locations that are comparable to the cleanup site

in outward environmental characteristics such as geological setting and

meteorological conditions. At RCRA sites, background is typically an on-site

location where no facility processing or disposal has been known to occur. At any

site, this definition is subject to opinion, based upon evaluation of the best

available information. Proximity to the facility is a key consideration in specifying

the locations that represent background conditions. Clearly, nearby locations are

optimal in terms of similarities of geological conditions and deposition of

anthropogenic materials, but these locations are also, because of their proximity to

the facility, potentially subject to low-grade contamination from the facility.

Distant locations may result in differing levels, not so much as a function of

facility versus nonfacility contamination but rather as a function of major

differences in native conditions and/or proximity to other sources. Definition of

appropriate background locations must balance these distances based upon

available site history. Once locations are selected to represent background levels,

sampling results from those locations can be evaluated to corroborate expectations

or to identify locations that do not meet assumptions about background

conditions.

The total number of background samples to be collected is the next major

consideration. Sample sizes can be directly estimated to achieve prespecified

statistical power and confidence by making reasonable assumptions about the two

expected “populations” of chemical concentrations (i.e., the site and background).

Alternatively, sample size can be indirectly determined by defining a desired

spatial coverage, then calculating the total number of samples to be collected by

dividing the entire area to be sampled by the predetermined coverage or surface
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area per sample (e.g., collecting samples using a 25-foot grid with one sample

collected per grid element). 

The sample size for background characterization should be considered in the

context of the sample size for the site being characterized. Statistical power for

most comparative tests is optimized with a balanced design. That is, to maximize

the ability to differentiate two populations (site versus background), similarly

detailed information is necessary about contaminant distributions from the two

areas. Optimizing statistical power must be balanced against the practical reality

that sampling on the site may already be extensive.

Following collection of samples from background locations or consolidation of

data from various sources, the frequency distribution of observed values can be

examined. Intuitively, background data are expected to be relatively consistent or

at least not to exhibit obviously bi- or multi-modal distributions of observations

over the concentration range observed. Probability plots and statistical testing for

adherence to commonly observed distributions (e.g., Shapiro-Wilk or ShapiroFrancia for normal or log normal distributions) are common methods to ascertain

that data meet these basic assumptions about background conditions. Where data

are composited from various sources and/or represent different methods or

conditions, preliminary evaluations should also include examining the extent to

which sampling factors (e.g., soil sample depths, analytical methods, specific

locations) could be reasonably expected to result in different levels of the

constituent. Spatial differences are the primary factors in considering background

soils. Tests for trend (e.g., Cox or Sen tests) are useful to detect the presence of

seasonal cycles and/or increasing or decreasing trends which would either

eliminate the location from background designation or indicate the presence of

upgradient effects independent of the site under investigation. If there are no

significant differences among factor levels, data can be considered to represent a

single population that represents background levels of naturally occurring or

anthropogenic constituents.

The issue then becomes how to apply the available background information to

determine which areas of a site represent incremental potential risk. Sample

results from background locations are commonly used to estimate some agreedupon proportion of the background population (such as an upper bound tolerance

limit that defines the concentration corresponding to the 95 th of 100 observations,

ranked from lowest to highest concentration). That point estimate is then used as

an upper limit to identify sample results from the site being investigated that

exceed background and therefore require remedial action. The advantage of point

comparisons is the relative simplicity of the method and calculations. 

Disadvantages to point comparisons are numerous. First, contrary to the

recommendations on sample size in the discussion above, the number of

observations from background locations is typically smaller than the number of

observations from the site. With the exception of uniform distribution, the

probability of a sample containing extreme values relative to the overall

population is lower than the more commonly occurring values from the center of

the distribution. In other words, less commonly occurring values require increased
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sampling. A reduced sample size may result in an underestimate of variability in

background levels. Because the calculated variance of the sampled population is

integral in the calculation of the tolerance limit, the reduced sample size may

result in a substantial underestimate of the upper concentration levels within the

background population. Second, even when applying an upper bound estimate

from a background sample, a certain proportion of values that truly represents

background will exceed that estimate. For example, 5 percent of background

values would be expected to exceed a 95 percent tolerance limit based upon true

knowledge of the population. Finally, the statistical power of point-to-point

comparisons is limited. 

Alternative methods are population-to-population comparisons. For example, ttests, Kruskal-Wallis tests, or Wilcoxon Ranks Sum tests in which the mean or

median from on-site samples are compared to the mean or median from

background samples; or the Quantile test which compares the upper end of the

two populations (background and site) for statistically significant differences.

Because no single statistical method is adequate to definitively define background

conditions, a combination of tools (population-to-population and point

comparisons) is recommended. Population-to-population comparisons, focusing

on the entire distribution as well as upper portions of the observations, provide a

more sensitive indication of the extent to which background and site populations

compare. Used in conjunction with point estimates (such as tolerance limits or

prediction limits), which establish an upper bound for a sample of a prespecified

size (as would be established in post-remedy verification sampling), these

comparisons optimize application of results from the background sampling effort.

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In 1996, SoCal embarked upon the remediation of PAHs at a former MGP site in

Alhambra, California. Because background concentrations of PAHs exceeded

concentrations corresponding to a one-in-one-hundred-thousand cancer risk, the

California EPA agreed that remediation to levels lower than background would

not be practical. The first challenge associated with remediating to background

included building a database of background PAH concentrations that could be

used to characterize background concentrations. In addition, statistical methods

had to be selected to support the site characterization and site remediation

decisions made in the restoration of the site to background conditions.

Site Background 

The Alhambra site had only operated as a MGP from 1906 through 1913. Because

oil was the most likely feedstock, the predominant residual expected to be found

was lampblack. Aerial graphs showed that the site sat vacant until about 1940,

when the first house was built. By about 1948, the site had been subdivided into 20

lots, each with a separate residence.

Site investigations revealed the presence of PAHs in shallow soils. Other

chemicals often associated with MGP operations such as metals, cyanides, reduced

sulfur compounds, phenolics, and benzene, however, were not detected in soil

above local background levels, or were present at levels below those that posed a
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health threat. Groundwater and soil investigations demonstrated that chemicals

had not migrated into groundwater. Based on these findings, the remediation of

the site focused on PAHs in soil.

Site remediation was performed under the supervision of the California EPA

DTSC. As a risk management policy, the DTSC generally requires

post-remediation cancer risks to be closer to the 10 -6 end of the 10 -4 to 10 -6

acceptable risk range recommended in the National Contingency Plan (NCP).

Most remediations approved by the DTSC achieve cleanup to a residual cancer

risk of 10-5 or lower. 

Background Database 

The database of background PAH concentrations includes analyses of 184 surface

soil samples collected from 20 different sites throughout Southern California. The

data set was subjected to several statistical tests to determine if the data comprised

a homogeneous population. Among the variables probed to explain variations in

the data were urban versus rural setting, analytical method, and sample collection

technique. After evaluating several different variables that might account for

variability in the data, it was concluded that the data could be considered a single

data set with a log normal distribution.

Developing the Remedial Action Goal 

Using cancer slope factors recommended by California EPA for cPAHs, the

concentrations of cPAHs (expressed as benzo(a)pyrene [B(a)P] equivalents)

corresponding to 10-6, 10-5, and 10-4 cancer risks for a residential exposure

scenario are 0.02, 0.2, 2.0 mg/kg, respectively. Using the database of background

PAH concentrations in Southern California soils developed as part of this

project, the 95% upper confidence level estimate of the mean concentration of

cPAHs (expressed as B(a)P equivalents) in soil is 0.24 mg/kg. This concentration

does not correspond to a cancer risk above the 10 -4 upper end of the acceptable

risk level recommended in the NCP, but it does correspond to risks in excess of

10-6 and 10-5.

Remediating soils in Southern California to PAH concentrations corresponding

to cancer risks in the 10-6 to 10-5 range would require reducing concentrations to

levels below background, an impractical goal. Remediating the site to

background concentrations would produce a site that posed no incremental risk

to humans or the environment beyond that posed by background PAHs. The

remediation goal adopted for the site was to restore each residential lot to a

condition such that people living at the site would have no more exposure to

PAHs than they would have had in the absence of the MGP operations. 

Achieving the Remedial Action Goal

Given the objective of restoring the site to background conditions, the ideal

remediation would have involved removing all PAHs that originated from the

former MGP operations. Over time, however, some of the PAHs from the MGP

operations had mixed with soil to such an extent that while the PAH

concentrations were elevated above background levels, the soil across much of

the site was not visually distinct. The practical approach developed for

remediating the site relied on field observation to visually identify lampblack
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and on statistical evaluations of sampling data to identify areas with PAH

concentrations above background levels. 

Because there is no single statistical test that could be applied to soil

concentration data to determine if the PAHs measured in a particular sample

exceed background concentrations, SoCal applied a few different statistical tests

to identify areas where concentrations probably exceeded background levels.

The statistical tests include both comparisons of point estimates as well as

distributions. To evaluate point estimates, the 95 th percentile, the upper

tolerance limit, and the upper prediction limit were considered. The appropriate

test for comparing distributions depended on the nature of the background

distribution and the site data. Visual comparisons of plots of the background

data set to the data from each lot were revealing, as were more rigorous

statistical tests such as a t-test or a Mann-Whitney test. Using these statistical

tests, an initial excavation target of 0.9 mg/kg of B(a)P equivalents for the

cPAHs was identified. Using the initial site characterization data, soils with

B(a)P equivalent concentrations above 0.9 mg/kg were initially identified to be

excavated.

Because approximately 5 percent of background soil samples had B(a)P

equivalent concentrations above 0.9 mg/kg, leaving some soil with PAH

concentrations above this level did not necessarily mean that the PAH

concentrations remaining after site remediation exceeded background levels.

This was an important practical consideration because some soil with elevated

PAHs level were in areas where excavation was not practical (e.g., beneath

foundations). 

The evaluation of data distributions was particularly important in the

determination of whether contamination had spread off-site. Because there is a

wide range of PAH concentrations in the background, the occasional detection

of a relatively high concentration of PAHs in boundary or off-site samples did

not necessarily mean that contamination had spread off-site. The use of a single

point estimate (e.g., two standard deviations above the mean, the upper

tolerance limit, etc.) as a test for determining whether any single data point

represents contamination beyond background can lead to false conclusions.

Demonstrating Achievement of the Remedial Action Goal

Based on the initial evaluation of the distribution of PAHs in soil at the site, the

excavation of soils meeting the two initial excavation criteria described above

(i.e., visible lampblack and B(a)P equivalent concentrations above 0.9 mg/kg)

was predicted to effectively restore each lot to background conditions.

Excavation was required on 18 of the 20 lots down to an average depth of 4 to 5

feet, including under crawl spaces and concrete slabs. Following excavation, soil

samples were collected from the side walls and bottoms of excavated areas and

statistical analyses were performed to determine if each lot had been restored to

background conditions. Post-remediation concentrations were also compared to

risk-based concentration limits designed to prevent acute or sub-chronic health

effects to ensure that none of the material left behind would pose such health

risks. The same statistical tests described above for determining whether and
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where remediation was needed were applied to the post-remediation data to

confirm that remediation was complete.

Conclusions

Because risk-based remediation goals for cPAHs were below background levels,

a method for developing background-based remediation goals was needed. The

traditional reliance on a single point estimate of background (e.g., two standard

deviations above the mean), however, can provide false indications of

contamination, particularly if there is a substantial overlap in the range of

background concentrations and the range of incremental concentrations

attributable to MGP operations.

By having a database representative of background concentrations over a sizable

geographic region, the characterization of background concentrations coming

from the database can be used at the many sites in the region. The size of the

database (i.e., 184 data points) allows for a high degree of statistical power in

distinguishing background concentrations from elevated concentrations that are

presumably related to MGP operations. In addition, through the use of

distributional comparisons to supplement point estimate definitions of

background levels, this approach can minimize the false identification of

background concentration samples as representing contamination. 

&RQWDFW

Bob Vogel, Southern California Gas Company, (213) 244-5880

#"42

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Generic administrative orders have been developed to streamline the regulatory

administrative process. Former MGP sites, as a subset of site characterization and

remediation experiences, lend themselves to generic administrative orders and

provide the opportunity to address environmental conditions under a consistent,

cooperative, mutually beneficial statewide agreement. Benefits of generic

administrative orders include:

  Comprehensive and consistent statewide strategies

  Reduced costs in negotiating agreements/orders

  Proactive environmental mitigation

  Emphasis on cooperation and common sense

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In the late 1990s, the North Carolina Manufactured Gas Plant Group (NCMGPG)

entered into a memorandum of understanding (MOU) with the North Carolina

Department of Environment, Health, and Natural Resources, Division of Solid

Waste Management (DSWM) to establish a uniform program and framework for

addressing manufactured gas plant sites in North Carolina. Under the MOU, all

investigations and, if required, remediation of specific MGP sties are to be
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addressed pursuant to one or more administrative orders of consent. The MOU

did not commit the NCMGPG to investigation and/or remediation any particular

former MGP site; rather it simply set in place the framework to be followed should

such an investigation/remediation be implemented. Implementation is formalized

through the execution of one or more of the generic administrative orders of

consent.

In establishing the generic administrative orders and preparing the MOU, the

NCMGPG and DSWM agreed to coordinate all North Carolina MGP site

investigations and remediations under the authority and jurisdiction of the DSWM

in order to ensure that all characterization activities were completed in a uniform

manner and to ensure that a single, regulatory agency (DSWM) would take control

of oversight of North Carolina former MGP sites. In executing the MOU, the

NCMGPG and DSWM agreed to:

 Negotiate in good faith to develop a uniform program and framework for the

investigation and, if required, remediation of former MGP sites within the

state

 Prioritize MGP sites in the state using the Site Screening and Prioritization

System (SSPS) developed by the Electric Power Research Institute

 Discuss and obtain regulatory acceptance of the most nearly applicable

cleanup standards that would be applied under CERCLA and Superfund

Amendments and Reauthorization Act of 1986, recognizing the need for

flexibility in addressing site-specific conditions

 Negotiate in good faith to develop appropriate alternatives to the site

assessment and remediation methodologies outlined in the generic

administrative orders

 Organize and sponsor group-funded technical seminar(s) and conference(s)

highlighting state-of-the-art technologies involving assessment and

remediation of former MGP sites

&RQWDFW

Brian Nicholson, North Carolina Department of Environment, Health, and Natural

Resources, (917) 733-2801 x353
4-1

Chapter 4

	

		

	
	




Expedited site characterization (as described in Section 3.2.7) encompasses the

use of tools and methodologies that streamline data collection, increase field

program flexibility, and allow for real-time on-site access to results.

Fundamentals key to an expedited site characterization include:

 On-site or rapid decision-making capabilities

 Use of field and analytical tools that facilitate real-time data collection and

interpretation.

 Use of non-intrusive or minimally intrusive geophysical and/or sampling

techniques

 Flexibility in the overall site characterization and remediation process

The tools and techniques described in this chapter offer alternatives to, and in

some cases, advantages over more traditional approaches to environmental

assessment of sites. These tools and techniques are less intrusive, and generally

allow completion of data collection in a more expeditious manner. In addition, the

majority of these tools allow practitioners immediate, on-site access to results

rather than requiring samples be sent to analytical laboratories for analysis.

Having the data available in real time while implementing the sampling program

allows the investigator to modify the sampling program based on early results.

The investigator can then make informed decisions about subsequent sampling

locations to cover an area of interest or to define the boundaries of identified

problem areas. 

In addition to being faster and less intrusive, these tools and techniques are costeffective, taking many samples and producing a large amount of data in a short

time. This is especially useful in expedited site characterizations, where the goal is

to first collect more data points of lesser quality in order to focus resources on

those areas of greatest concern. Subsequent phases of field work can then be

implemented to collect fewer data points of better quality at predetermined

locations, if necessary, to complete the site characterization. 

These tools and techniques can be combined to form a site-specific expedited field

program. Prior to developing such a program, however, thought must be given to

the project’s data needs and the ways in which the data will be used. Once these

DQOs have been formulated, different site characterization tools and techniques

can then be brought together, as appropriate for different site conditions.

Flexibility in decision-making during the field program will also be required to

ensure that only necessary and useable data points are collected. Each tool and

technique in this chapter has strengths and weaknesses. The following table

summarizes available information. Additional information is presented in the
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4-2

chapter proper for use by the practitioner. The order in which the tools and

techniques discussed in this chapter does not reflect any ranking of their relative

effectiveness.
4-3

Expedited Site Characterization Tools and Techniques

Name Description Benefits Limitations Approximate Cost

Direct Push Methods/Limited Access DrillingDirect Push/Limited AccessDrilling (Geoprobe, PowerPunch, Strataprobe,Precision Sampling, andothers)

Used to collect soil, groundwater andsoil gas samples and for identifyingstratigraphy and nonaqueous phaseliquids. 

• Faster, cheaper way to explore subsurfacecharacteristics• Can be linked to on-site analysis for real timemapping• Widely available• Can install small diameter wells and vapor extractionpoints• Less intrusive• Produces small volume of investigation-derivedwaste

• Limited range of use (with refusal/depth limitedto <100 ft max; typically 25 to 30 feet)• Does not allow for large well installations• Limited use at locations with buried obstructions(e.g., foundations and coarse grain materials)• Potential for cross-contamination fromsingle-tube rigs. 

$1,000 - $1,500 per day;typical production 10-15shallow (<40 ft) pushes perday

Cone Penetrometer Push sampler used for geologic

logging and to collect in situmeasurements of geologic propertiesand pore pressure. Can be used tocollect soil gas and groundwatersamples.

• Rapid collection of objective stratigraphic information• Can penetrate harder zones than most direct pushmethods• Produces small volume of investigation-derivedwastes

• Does not collect soil samples for analysis orinspection• Large, heavy rig may limit access• Cannot install wells• Potential for cross contamination fromsingle-tube rigs

Typically one-third that ofconventional soil borings, onper foot basis

Simulprobe Driven sampler used to collect soil,

groundwater, and soil gas samplesthrough a casing or auger advancedto desired sampling depth.

• Collects soil and either groundwater or soil gassamples at same stratigraphic interval on the samepush• Can be used with field instrument to screen for VOCswhile pushing• Can be used in conjunction with a variety of drillingmethods

• Limited availability• Multiple moving parts increases potential forbreakage or sticking• Depth to which sampler can be pushed limited

Tools rent for $150/day or$650/week, plus rig cost ofabout $1,500 per day.

Hydropunch Direct push tool used to collect

depth-discrete groundwater samplesat a discrete level in a single push.

• Collects groundwater sample at a discrete depth• Can be used with field instrument to screen variousdepths

• Data subject to interference from turbidity• Potential for cross-contamination if sampler isdriven across hydrostratigraphic zones

Tools rent for $150/day or$650/week, plus rig cost ofabout $1500 per day.

Waterloo Profiler Direct push sampler used to collect

depth-discrete groundwater samplesat various levels in a single push.Useful in identifying thin, highconcentration plumes that may bemissed or underestimated (viadilution) with monitoring wellsampling.

• Generates a vertical profile of groundwater quality ona single push (typical vertical separation of about 2 to 5feet)• Faster and less prone to cross-contamination(vertically) than multiple pushes with conventional pushsamplers

• Sampling depth generally limited by drillingmethod• Not applicable to low-permeability settings• Tool available through limited number ofvendors

$1,500 to $2,000 per day(2-person crew, including alldecon and supportequipment); typicalproduction is 150 - 200 ft perday. Waterloo samplerequipment may bepurchased from SolinstCanada, Inc., for $US 2,700. 
4-4

Expedited Site Characterization Tools and Techniques, continued

Name Description Benefits Limitations Approximate Cost

Multi-Level Groundwater SamplersWestbay System Fixed multi-level sampler built for a

specific well installation. Access isthrough a single standpipe withmechanical "ports" that are openedand closed during sampling. Used toprovide multi-level sampling andhydraulic head measurements.

• Provides direct samples of formation water• Allows head measurements

• Mechanically complex• Not adjustable or portable between wells• Requires specially constructed wells

Approximately $30,000 for a5-level system ranging from50 feet to 200 feet in depth.Includes installation but notsample analysis.

Waterloo Sampler Fixed multi-level sampler built for a

specific well installation. Access is through bundled flexible tubes thatare accessible at the surface. Usedto provide multi-level sampling andhydraulic head measurements inspecially-constructed well. Smaller"drive point" units available forshallow installation.

• Provides direct samples of formation water• Reduces purge volumes• Removable or permanent systems available

• Mechanically complex• Specially-ordered materials necessary• Removable packer system sometimes difficultto cost-effectively reuse• Requires trained technician for installation

Approximately $25,000 for a5-level system ranging from50 feet to 200 feet in depth.Includes installation but notsample analysis.

Diffusion Multi-LayerSampler (DMLS)

Portable multi-layer dialysis cellpassive groundwater sampler. Usedto characterize vertical variation ingroundwater quality in either openrock boreholes or in wells with longwell screens. Can be used toestimate groundwater flow velocityusing borehole dilution method. 

• Portable between wells• Allows vertical characterization of groundwater in asingle borehole or well• Requires no purging

• Not widely used• Does not allow head measurements• May not be appropriate for zones with strongvertical gradients

About $3,000 for 2- to3-meter-long units. Costincreases with increasinglength. Need to addadditional costs related tosample analysis andequipment installation. 

Discrete Point SamplersDiscrete Point Samplers Discrete point sampler used to collect

representative groundwater sampleat a distinct elevation or points ofinflow in either open boreholes orscreened wells.

• Permits groundwater sampling from discrete verticaldepth• Minimizes mixing of water from different levels duringsample collection• Portable

• May require training to operate sampler• May be difficult to obtain complete seal

$150-$2,000 for purchasedsampler.
4-5

Expedited Site Characterization Tools and Techniques, continued

Name Description Benefits Limitations Approximate Cost

Analytical Field ScreeningRapid Optical Screening Tool(ROST)

Sampling and screening technologyused to field screen for petroleumhydrocarbons and othercontaminants. 

• Rapid, real-time geologic and hydrocarbon data• Can be used to converge on area of interest• Works for both fuel (aromatic) hydrocarbons andcreosote (polycyclic aromatic hydrocarbons)• Generates little investigation-derived wastes duringsampling

• Limited availability• Limited to unconsolidated geology (same asCPT)• Provides only relative concentration data

$4,000 to $4,500 per day(reflects recent costreduction). Production up to300 feet per day.

X-Ray Fluorescence (XRF) Field screening tool used to analyze

trace metals in soil, sludges, andgroundwater.

• No waste generated• Little sample preparation required• Easily transported to the field

• Limited penetration depths• Susceptible to interference from water,petroleum, and soil variability• Poor detection limits for some metals• Radioactive source in analyzer

$2,000/week.

Colorimetric Field Test Kits Field test kits used to detect the

presence or determine theconcentrations of contaminants in soiland water.

• Inexpensive and easy to use• Available for a wide range of concentrations forhundreds of chemicals• Can be used for remote sampling

• Relatively high detection limits• Possible interference by naturally occurringchemicals and other contaminants• Possible difficulty in reading colorimetricmatches in low light

Handby Kits - $1300/30samplesPetroFLAG - $800/10samplesPetrosense - $150/weekQuick Testr - $275/week

Immunoassay FieldScreening

Field test kit used to detect targetchemicals in soil and other samplers.Most kits use competitive enzymelinked immunosorbent assay (ELISA)type.

• Produces rapid, real-time analytical data onsite• Can be used to select samples for laboratory analysisand to define limits of contamination

• Requires site-specific calibration• Does not speciate individual PAHs• Does not work effectively at MGP sites wherecrude oil was used• Does not produce quantified concentrations oftarget chemicals• Requires test runs to ensure adequacy

Approximately $20 -$55/sample excluding labor

Mobile Laboratory Mobile facility providing onsite soil,

water, and air analyses.

• Rapid onsite detection of contaminants• May reduce mobilization/demobilization charges forfield projects• Can rapidly perform time-critical analyses

• More expensive for standard turn-aroundanalysis• Not all mobile laboratories use USEPAanalytical methods

$2,500 to $3,000 for rental;$13 to $30/sample forexpendables.
4-6

Expedited Site Characterization Tools and Techniques, continued

Name Description Benefits Limitations Approximate Cost

Geophysical SurveysElectromagnetics Non-intrusive electromagnetic

geophysical tool used to locateburied drums, landfills, bulk buriedmaterials, etc. Can be used todetermine depth to the water tableand to delineate electricallyconductive (high dissolved solids)contaminant plumes.

• Non-intrusive• Can provide large quantities of detailed data in shorttime

• Need expert subconsultant to plan survey andinterpret data• Data affected by power lines and metalbuildings, cars, or other large metal items• Problematic in iron-rich soils and fill with largeamounts of diffused metal wastes

Approximately $3,500,including data collection andinterpretation for a one-acresite.

Seismic Refraction Non-intrusive geophysical surveying

tool used to determine depth tobedrock and/or water table. Can beused to define bedrock surface,buried channels, etc.

• Non-intrusive• Can provide large quantities of detailed data in shorttime

• Need expert subconsultant to plan, collect, andinterpret data• Data subject to interference from complexgeologic strata• Needs to be correlated with other site-specificsubsurface data• Heavy traffic or numerous surface obstructionsmay be problematic

Approximately $10,000including data collection andinterpretation for a one weeksurvey.

Ground Penetrating Radar(GPR)

Non-intrusive geophysical surveyingtool used to locate buried waste,drums, tanks and voids, and todetermine the depth and thickness ofsoil and bedrock.

• Non-intrusive source and detectors• Can provide large quantities of detailed data in shorttime

• Need expert subconsultant to plan, collect, andinterpret data• Data deteriorates with increasing surfacemoisture or clay in subsurface• Problematic in iron-rich, deeply weathered soils

$10,000/week for 5 to 7 linemiles of interpreted data.

Magnetometry/MetalDetection

Non-intrusive geophysical survey toolused to detect and map burieddrums, metallic pipes, utilities andcables, tanks and piping. Also usedto delineate trenches and landfillswith metal debris.

• Non-intrusive• Relatively easy for non-expert to use• Can provide large quantities of detailed data in shorttime

• Depth and detail not obtainable• Cannot distinguish between types of metallicobjects• Nonferrous metallic objects are invisible

$500/month for equipmentrental costs only.

Electric Logging Includes electrical resistivity

methods, induction logs, selfpotential logs, and fluid conductivitylogs. Uses electrical resistivity toidentify different hydrogeologic zonesaround a borehole.

• Rental equipment available• Specialized training not required• Quantitative data may require corrections

• Requires uncased borehole• Electrical resistivity and self-potentialtechniques require conductive borehole fluids• No quantitative measurements (other thandepth)• Induction logging requires a dry borehole orborehole with non-conductive fluids

$1,200 - $2,500 day. (Canlog 5-7 100-foot wells perday.)
4-7

Expedited Site Characterization Tools and Techniques, continued

Name Description Benefits Limitations Approximate Cost

Geophysical Surveys, cont.Mechanical Logging Includes flow-meter and caliper

logging. Used to identify waterproducing zones. Flow-meter loggingprovides semi-quantitative flowmeasurements when used inconjunction with caliper log (whichmeasures borehole size androughness and locates fractures andwashouts).

• Provides direct measurement of vertical flow in wellbore

• Flow-meter logging is relative insensitive at lowvelocities• Most applications of flow-meter logging requiresa pumping or flowing well• Caliper logging is required for interpretation offlow-meter log

$500 - $600 per well, whenrun as part of multiple logsuite. Flow-meter only (withcaliper) is approximately$1,500 - $2,500 per well.

Acoustic (Sonic) Logging Uses acoustic energy to determine

the relative porosity of differentformations. May be used to identifythe top of the water table, locateperched zones, and assess the sealbetween a casing and formationmaterial.

• Useful for characterizing rock aquifers• Allows porosity determination without use ofradioactive source

• Not applicable in shallow wells or in unsaturatedconditions• Relatively complex test; requires skilledoperator for reliable results

$1,500 - $4,500 per well.

Radiometric Logging Includes neutron logging and natural

gamma logging. Used to estimate theporosity and bulk density of aformation and to locate saturatedzones outside casing. Gammalogging is used to evaluate downholelithology, stratigraphic correlation,and clay or shale content.

• Rental equipment available• Specialized training not required• Good tool for performing infiltration studies

• Neutron logging requires handling radioactivesource and may be limited to case boreholes• Natural gamma logging may provide anon-unique response• Natural gamma logging may respond to thepresence of phosphate minerals of micas or maymistake feldspar for clay or shale

For neutron logging, $2,500to $5,000 per well dependingon well depth and number of other logs run in conjunction.For natural gamma logging,$1,200 - $2,500 day. (Canlog 5 - 7 100-foot wells perday).

Thermal Logging Uses temperature differentials for

flow and injectivity profiling, inconjunction with flow-meter logging.

• Supplements flow-meter log for identification ofproducing zones

• Requires fluid-filled borehole for testing• Interpretation of log complicated if internalborehole flow is present

$500 - $600 per well, whenrun as part of multiple logsuite. Temperature log only $1,500 - $2,500 per well.

Video Logging Downhole videotaping to provide

visual inspection of a well interior,detecting damaged sections ofscreen and casing, and to detectfractures, solution cracks andgeologic contacts in uncased holes.

• Allows visual inspection of the interior of the well • Requires very clear water for successful survey

• Not suitable for open boreholes inunconsolidated formations

$400 to $3,000 per well.
4-8

Expedited Site Characterization Tools and Techniques, continued

Name Description Benefits Limitations Approximate Cost

Soil Gas SurveysPassive Soil Gas Measures relative concentration of

contaminants through subsurfacedetectors sensitive to diffusion.

• Can be more sensitive than active soil gas, soil, orgroundwater sampling for detecting presence of tracecontaminants• Can be used in areas of low-permeability soil

• Does not measure direct concentration• May be difficult to collect data at depth forvertical characterization• Requires 2 to 4 weeks for sample collection

Approximately $250 persample location, includinganalysis and reporting; about$50 - $100 per locationinstallation and retrieval.

Active Soil Gas Uses a vacuum pump to induce

vapor transport in the subsurface andto instantaneously collect samples ofcontaminants in the vapor phase.

• Provides real-time data• Rapid results allows user to converge on areas ofinterest• Provides direct measure of vapor concentration• Can be used to evaluate vertical changes in soil gasconcentrations

• Samples must be collected at least 10 to 20 feetbgs• Cannot be used in areas of relatively lowpermeability• May be adversely affected by transientprocesses (e.g., barometric pressure) andstationary features (e.g., pavement)

Approximately $3,000 to$4,000 per day

Contaminant Migration EvaluationPush-Pull NaturalAttenuation Test

Injection/withdrawal test (single well)to document and quantify microbialmetabolism.

• Can document microbial metabolism, loss ofdegraded contaminants, production of degradationproducts, and yield estimates of zero- and first-orderdecay constants• Can use wells already installed• Provides in situ data

• Not widely used• Can have difficulty when decay rate is slowrelative to groundwater flow rates

$12,000 to $15,000 for 2 to 3wells at one site for BTEX.Costs may be higher forother contaminants (becauseof more expensive analysis).

Partitioning Interwell TracerTest (PITT)

Injection/withdrawal test (2 wells) toquantify volume and estimatedistribution of nonaqueous phaseliquids (NAPLs).

• Can provide quantitative estimates of NAPL volume• Can be used to design remediation methodstargeting a NAPL source• Is relatively accurate compared with other in situ teststhat utilize point values or small aquifer volumes

• Expensive• Technology is patented • Most experience is with solvents

$100,000 to $400,000depending on scale of test.

In Situ Bio/GeochemicalMonitor (ISM)

Allows for in situ measurement ofbiochemical reaction rates andretardation factors for both organicand inorganic compounds throughthe subsurface introduction andmonitoring of tracers and reactants.

• Reduces the time and cost of obtaining site-specificbiological and geochemical data• Provides in situ measurements of biochemicalreaction rates• Provides estimated rates of denitrification duringbiodegradation• Provides estimated retardation rates for organic andinorganic compounds

• Testing is complex and requires trainedpersonnel• Small aquifer volume tested means results maybe affected by small-scale variations in aquiferproperties• Typically applicable only with permeabilities>10-4 cm/sec

$3,000 for equipment only.
4-9

Expedited Site Characterization Tools and Techniques, continued

Name Description Benefits Limitations Approximate Cost

Other ToolsMicro-Scale Extraction (forPAHs)

Alternative laboratory extractionprocedure for mono- and polycyclicaromatic hydrocarbons, chlorinatedphenols, PCBs, mineral oil, andselected nitrogen- and sulfurcontaining aromatic hydrocarbonsprior to analysis.

• Small sample volumes required• Fast laboratory turnaround times• Minimal laboratory wastes• Quantitative results for individual components

• Relatively new procedure Dependent upon analysis.

Can reduce costs by over50% in certain situations.

PAH Sample Filtration In-field or laboratory filtration of water

samples prior to PAH analysis toestimate the 'true' dissolvedconcentration by removing potentialfor colloidal contribution of PAHs.

• Eliminates high bias in PAH concentrationmeasurements introduced by artificial colloidalentrainment• Inexpensive• Requires minimal training to implement

• Low bias resulting from elimination ofnaturally-occurring colloidal transport of PAHs• Dissolved or colloidal contaminants may adsorbonto the filter or apparatus

Minimal cost when comparedto overall analytical costs.(Typical PAH analysis costs$200 to $300/sample.)

Inverse Specific CapacityMethod

Specific application of push sampler(Geoprobe and others) to linkgroundwater quality data obtainedfrom push sampler with an estimateof hydraulic conductivity in thesampled zone

• Allows vertical profiling of variations in horizontalhydraulic conductivity to be assessed

• Provides hydraulic conductivity for only smallvolume of aquifer• Need site-specific permeability data fromconventional means (pumping or slug tests inwells) to convert specific capacity to hydraulicconductivity• Only appropriate for zones having permeabilityranging from 10-1 to 10-5 cm/sec

Negligible cost, assumingthat a peristaltic pump andpush sampler already are inuse at the site (assumestypical time for test rangesfrom 5 to 10 minutes). 

Hand Augering/Trenching/Pot Holing

Field surveying and samplingtechnique.

• Inexpensive where labor is cheap• Can be used to expose buried objects• Discrete and can get into tight locations

• Hand augering and test pits are depth limited• Pot holing and test pits are visible to public• Borehole/slope stability problems• Waste management may be a problem

Materials and equipmentcosts are minor. Cost isdependent on local laborcosts.

Noise and FugitiveEmissions Controls

Barriers and controls to minimizenoise and fugitive emissions duringsite characterization and remediation.

• Protects community and workers• Limits noise and air pollution• Minimizes the migration/transport of contaminants

• May be cost- and effort-prohibitive on a largescale• Controls may make field work logistically morecomplex and/or limit rate of completion

Ranges from $200-$500/dayfor water sweeping to>$10,000 for complete siteenclosure.
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4-10

	

			


	

Described below are 13 categories of new and existing tools and techniques that

are currently available for expediting characterization of former MGP sites. The

cost of using the tools and techniques and the results generated will vary from site

to site depending upon accessibility, cost of labor, types and concentrations of

contaminants found, hydrogeology, and other characteristics. Although many of

these tools and techniques have been used successfully at former MGP sites,

practitioners should choose tools based on the particular conditions at their site(s).

Where possible, references are listed so that readers can contact representatives of

projects where the tools and techniques have been used.

	
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Tools in this category provide faster and cheaper ways to explore subsurface

characteristics than have been available in the past. These methods are typically

less intrusive, generate fewer investigation-derived wastes than past techniques,

and permit sample collection in areas with limited clearance. When combined

with on-site data analysis, these tools provide a powerful way to survey soil (and

groundwater) for contaminants.

Some of the tools described herein may be limited to depths of 25 to 30 feet; others,

however, are not depth-constrained. These tools generally create small-diameter

boreholes and therefore do not allow for the installation of large wells. In addition,

they may only allow for one-time “snapshot” or “grab” sampling. Tools included

in this category are:

 Direct-Push Limited Access Drilling Techniques (such as GeoProbeTM, Power

PunchTM, StrataprobeTM, and Precision SamplingTM)

 Cone Penetrometer

 SimulprobeTM Sampler

 HydropunchTM

 Waterloo Profiler

 Westbay System

 Diffusion Multi-Layer Sampler

 Waterloo System

 Point Sampler or Dual Packer Sampling

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A wide range of direct-push and limited access drilling techniques is available for
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4-11

collecting soil, vapor, and groundwater samples and for identifying stratigraphy

or NAPLs. Some vendors, such as GeoProbeTM, have also developed specific

application probes (e.g., the conductivity probe) that can be used in conjunction

with a drilling rig to survey a site or install small-diameter wells. These drilling

methods have been successfully applied at former MGP sites for delineating

source areas, screening aquifers for plumes before well installation, and collecting

subsurface information in hard-to-access areas.

Direct-push drilling rigs typically consist of hydraulic-powered

percussion/probing machines designed specifically for use in the environmental

industry. “Direct push” describes the tools and sensors that are inserted into the

ground without the use of drilling to remove soil and make a path for the

sampling tool. These drilling rigs rely on a relatively small amount of static

(vehicle) weight combined with percussion for the energy to advance a tool string.

The small rig size allows work in limited access areas. Below is a photograph

showing a typical direct-push drilling rig.

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Direct-push drilling rigs, such as the GeoProbeTM, are more efficient at drilling in

shallow, soft areas but are not typically capable of drilling through a thick

subsurface structure such as a gas holder foundation. Although limited in depth

and often unable to drill through buried foundations at an MGP site, this

technology can provide useful information about the location and depth of buried

structures without puncturing them, which would create a route for cross

contamination. In addition, this technique is effective for collecting soil,

groundwater, and soil vapor grab samples. It is most efficient to depths of

approximately 30 to 50 feet (depending on soil type).
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Vendors of direct-push drilling rigs include GeoProbeTM, Power PunchTM,

StrataprobeTM, and Precision SamplingTM. This drilling technology is well

understood and provides reliable results. The cost of a direct-push drilling rig is

approximately $1,000 to $1,500 per day, not including sampling tools and related

expenses.

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 Small rig size suitable for tight spaces around aboveground structures or utility

areas such as substations

 Small volume of investigation-derived waste (IDW) produced

 Continuous coring or discrete soil samples both possible

 Sampling of soil, groundwater, and vapor possible along with installation of

small-diameter wells

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 Limited use at locations with buried obstructions (e.g., foundations)

 Potential for cross contamination from single-tube rigs

 Rods can get lost in tight soils

 Small diameter wells installed using these direct-push rigs may be difficult to

develop

 Water samples collected from direct-push tubes typically contain considerable

suspended sediment; may yield biased results for turbidity-sensitive

constituents such as lead and PAHs

 Repeated pushes required from ground surface in order to vertically profile a

site (i.e., collect water samples at different depths at the same location) unless

special equipment (i.e., Waterloo system) is used

 Impractical (because of slow sample collection) in low-permeability soil or

when attempting to collect samples at relatively shallow depths below water

table

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Both GeoProbeTM and Precision SamplingTM direct-push drilling rigs were used at

PG&E’s CWM former MGP sites. The rigs were used to:

 Collect deep soil and grab groundwater samples from within active

substations

 Collect grab groundwater samples to delineate the extent of offsite

groundwater contamination so that downgradient monitoring wells could be

placed at the edges of plumes (to act as sentry wells against continued

downgradient plume migration)
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4-13

Reference: Holguin, Fahan & Associates, Inc.

 Quickly establish the extent of lampblack and coal tar in shallow soils at the

locations of former lampblack separators, lampblack dumps, and tar pits

When the rigs were unable to drill through obstructions, this helped verify the

location, depth, and extent of buried foundations. Soil samples from depths

beneath former foundations (collected when the drilling rig was able to push

through the former foundations) provided information about the types and

volume of buried MGP wastes. At locations where cross contamination was a

significant concern, Precision Sampling’s dual-tube direct-push drilling rig was

used to minimize the amount of soil and/or waste that may be transported

downward by the driving rod.

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CPTs were initially developed as engineering tools for determining the capacity of

soils to support foundations and pilings. These tools are a quick, reliable, and welltested means to determine the continuity of stratigraphy, the depth to the water

table, and the thickness of stratigraphic layers. More recently, the hydraulic

pushing equipment on a modern CPT rig has been used to advance probes and

samplers into subsurface soils. Examples of such probes/samplers include vapor

samplers, soil samplers, the HydropunchTM, LIF probes, and resistivity probes.

A traditional CPT survey is a continuous penetration test in which a cone-shaped

rod is forcibly pushed into the soil with hydraulic rams. Sensors electronically

measure the resistance at the cone’s tip and along the cone’s sides. The function of

the relative density of the sediment is then correlated to the soil textures to

determine the site’s stratigraphy. A schematic figure of a CPT rig is shown below.
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4-14

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Modern CPT rigs are capable of collecting the same data as conventional drilling

rigs. CPT data are high quality, most often meeting DQOs, cost effective, and

typically pose minimal health and safety concerns. In addition, CPT testing does

not generate any drill cuttings. CPT drilling rigs can generally penetrate to depths

of 100 to 150 feet below ground surface (bgs) in normally consolidated soils. The

principal disadvantage of CPT rigs is that they cannot penetrate as deeply as

conventional drilling rigs.

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There are several CPT vendors in the United States, most of whom support both

traditional geotechnical CPT projects and modern environmental investigations.

The types of CPT-mounted sampling equipment and probes vary, however,

among vendors. Costs for CPT are typically about 30 percent (on a per-foot basis)

of the cost of conventional soil borings installed using traditional methods such as

hollow-stem auger drilling. CPT costs are comparable with the modern directpush drilling technologies offered by GeoProbeTM, Precision Sampling, Inc., and

others.

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 Can penetrate harder zones better than most direct-push methods

 Produces small volume of IDW

 Can be used for sampling groundwater and soil gas

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 Potential for cross-contamination from single-tube rigs

 Does not allow continuous coring or discrete soil samples

 Cannot be used to install wells

 Large, heavy rig may preclude access to some locations

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The SimulprobeTM sampler is a soil, soil gas, and groundwater sampling tool

designed to be driven by either push or drive sampling technology. The sampler

reduces the potential for cross-contamination by precharging its sample canister

with nitrogen and by covering the sampler with a latex condom. Precharging the

sampler with nitrogen prevents water from entering the sample canister until the

sample is collected. The condom ensures that the sampler remains

uncontaminated until driven into undisturbed soil.
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4-15

One significant advantage of the

SimulprobeTM sampler is the ability to

obtain a soil core sample at the exact

depth where the grab groundwater or

soil gas sample was obtained. This allows

the user to determine the lithology at the

point of sampling. In addition, the

SimulprobeTM sample chamber fills at a

slower rate than other samplers

(controlled by the rate at which the

nitrogen is bled off), thereby reducing

turbidity. The sampler also has a settling

chamber so that any excess sediments

that enter the chamber settle out before

the water sample is transferred. The

adjacent photograph shows a

SimulprobeTM sampler.

The SimulprobeTM provides continuous sampling of soil gas in the vadose zone.

When the probe is pushed through the vadose zone, soil gas is extracted under the

vacuum and measured continuously in an organic vapor analyzer located above

ground surface. If desired, a syringe can be inserted and a sample of soil gas can

be extracted and analyzed by gas chromatography (GC) at any time.

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Sampling with the SimulprobeTM, as with other similar tools, is limited by the

depth to which the tool can be driven. Other geologic conditions, such as flowing

sands, also limit the tool’s effectiveness and range.

When a grab groundwater sample is collected using the SimulprobeTM sampler, the

water canister is first charged with nitrogen (usually 60 pounds per square inch

[psi]/100 feet of hydrostatic head), and the entire sample device is covered with a

latex condom. The SimulprobeTM is then slowly lowered to the bottom of a

borehole and hammered 21 inches into the subsurface to collect a soil core. The

device is then pulled back 2 to 3 inches to retract the sliding drive shoe and expose

the circular screen. A valve is opened to allow the nitrogen pressure to bleed off

from the water canister so water can enter the sample chamber under ambient

hydrostatic pressure. After the water sample has been collected, the water canister

is repressurized to prevent leakage into the sampling device, pulled out of the

borehole, and emptied into appropriate sample containers.

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The latex condom covering the SimulprobeTM sampler is designed to minimize

cross-contamination during sampling, therefore making the SimulprobeTM a tool

for grabbing groundwater samples before well installation, especially in areas

where cross-contamination is of concern. Combined with push- or hammer-driven

sampling (such as GeoProbeTM) and in-field analysis, it provides a fast, effective

method for obtaining survey-level data for refining monitoring well and
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4-16

groundwater plume locations. In addition, collecting soil samples at the same

interval as the sampled groundwater allows for better linkage between

hydrostratigraphy and groundwater and contaminant movement in the

subsurface.

The rental cost of the SimulprobeTM sampler alone (direct from the vendor) is

approximately $150 per day or $650 per week. Drilling costs can add

approximately $1,500 per day to total sample collection costs. Sampling depth and

frequency, site hydrostratigraphy, and buried obstructions can significantly

impact the tool’s effectiveness.

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 Collects soil and either groundwater or soil gas samples at the same

stratigraphic interval in the same push

 Can be used with field instruments to screen for volatile organic compounds

while pushing

 Field tested and proven

 Can be used in conjunction with a variety of drilling tools

 Latex condom minimizes cross-contamination during sampling

 Nitrogen or helium can be used to purge the canister to create an inert

atmosphere before sample collection, thereby improving the quality of

chemical parameters for natural attenuation monitoring

 Canister attachments can be used as pneumatic bailers inside wells or

boreholes (e.g., for sampling below NAPL layers)

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 Limited availability (though may be available through local drilling firms)

 Multiple moving parts increase potential for breakage or sticking

 Depth to which the sampler can be pushed/driven limited

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Field investigations conducted at PG&E’s Chico former MGP site identified PAHs

and petroleum hydrocarbons in the shallow water-bearing zone. However, the

hydrostratigraphy below the water-bearing zone was not known, nor was

information available on the water quality of deeper water-bearing zones. In order

to determine the vertical extent of MGP-related constituents in groundwater and

to identify the next deeper, unimpacted zone for monitoring (as a sentry well), the

SimulprobeTM sampler was used with resonant sonic drilling. Grab groundwater

samples were then collected from the two water-bearing zones directly underlying

the shallow groundwater. 

The first, deeper water-bearing zone was identified at 47 feet bgs. Grab

groundwater samples were successfully collected from this zone using the
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4-17

SimulprobeTM. Because naphthalene-like odors were detected in the field from this

groundwater zone, the SimulprobeTM was advanced to the next deeper waterbearing zone, identified at 97 feet bgs. Flowing sands encountered at this depth

combined with the vibrations from the resonant sonic drilling jammed the sampler

and prevented collection of a grab groundwater sample. Use of the SimulprobeTM

is not recommended with a resonant sonic drilling rig or where flowing sands are

present.

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The HydropunchTM is a direct-push tool for collecting a depth-discrete

groundwater sample inside a boring without installing a well. The HydropunchTM

has been successfully used for collecting grab groundwater samples at former

MGP sites to quickly delineate the extent of a groundwater plume without well

installation or to quickly determine the best location or depth for screening a

monitoring well.

The HydropunchTM sampler is advanced with a hammer-driven tool to collect a

groundwater sample from a particular depth. The sampler is pushed to the proper

groundwater sampling zone and then withdrawn to expose an inlet screen. The

screened interval is approximately 3 to 5 feet long. Groundwater can be collected

from multiple depths within a single borehole although the tool must be

withdrawn between samples. The following figure is a schematic diagram of the

HydropunchTM sampler.

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The key factor affecting the accuracy

of groundwater analytical results

collected via the HydropunchTM

sampler is the turbidity of the grab

sample. Because the sample is

collected from a borehole instead of a

developed well, the sample may be

turbid. If the sample is not filtered

before laboratory analysis,

hydrophobic chemicals (such as PAHs

and metals) sorbed onto the

suspended sediments may cause

erroneously high concentrations. In

addition, the HydropunchTM sampler

limits the sample volume collected per

push, so this tool is best used in a

permeable zone where there is

reasonable recharge into an area 3 to 5

inches thick. It is possible to attach a

peristaltic pump to the HydropunchTM sampler to pump larger volumes of
&KDSWHU 

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4-18

samples if volatilization is not an issue. Finally, as with any single-tube directpush probe or sampler, there is a potential for cross-contamination between

groundwater zones. However this concern can be mitigated by using conductor

casings. Floating-layer hydrocarbons may be sampled with a small-diameter bailer

lowered through the push rods in one of the HydropunchTM tools. 

$SSOLFDWLRQV DQG &RVW

The HydropunchTM sampler is a fast and inexpensive method for collecting a

groundwater sample without installing a well. The HydropunchTM is well

understood and provides reliable results.

The cost of a HydropunchTM sampler is approximately $150 per day, in addition to

the drilling rig and associated equipment. 

%HQHILWV

 Provides reliable data

 Field tested and proven

/LPLWDWLRQV

 Data subject to interference from turbidity

 Potential for cross-contamination if sampler is driven across

hydrostratigraphic zones

&DVH 6WXG\

6WRFNWRQ )RUPHU 0*3 6LWH

Grab groundwater sampling at the Stockton former MGP site was performed

using the HydropunchTM sampling tool for field screening to determine monitoring

well locations at the edge of the plume. Samples were collected from two depths

and sent to a laboratory for rapid analyses. Sample results were used successfully

to determine whether the proposed well locations were at the edge of the

groundwater plume (analytical results showed no detectable levels of

contamination). Alternate well locations were identified when the HydropunchTM

samples showed detectable levels of contaminants.

 :DWHUORR 3URILOHU

7RRO 'HVFULSWLRQ

The Waterloo Profiler (patent pending) is a groundwater sampling tool designed

to collect depth-discrete groundwater samples in a single borehole with one probe

entry. The Profiler consists of a tip containing multiple screened ports located

around it. The Profiler tip is connected to 3-foot lengths of heavy-duty threaded

steel pipe that extends to the ground surface. The Profiler is advanced by pushing,

pounding, or vibrating the steel pipe into the ground using one of Precision

Sampling, Inc.’s custom-made sampling rigs. Groundwater samples are conveyed

to the surface via small-diameter tubing that is attached to a fitting inside the

Profiler tip. The internal tubing, made of stainless steel or Teflon, passes up
&KDSWHU 

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4-19

Reference: Precision Sampling, Inc.

through the inside of the pipes to a pump and sample collection station located at

the ground surface (Precision Sampling, 1998). Chemical concentrations in highly

stratified formations can vary by several orders of magnitude over vertical

distances of 1 foot. One significant advantage of the Waterloo Profiler is its ability

to vertically profile contaminants in microstratigraphy without having to

withdraw and reinsert the probe. This minimizes cross-contamination and the

need for frequent tool decontamination between sample collection. The Profiler

can be pushed through clay and silt beds without plugging, which makes vertical

profiling easy.

2SHUDWLRQDO &RQVLGHUDWLRQV

Sampling with the Waterloo Profiler, as with similar tools, is limited by the depth

to which the tool can be driven. Other geologic conditions, such as fine-grained

sediments, also limit the tool’s effectiveness and range. 

Sample collection with the Waterloo Profiler is the most time-consuming part of

sampling operations. Sample collection can vary from 10 minutes per sample in

coarse-grained sand and gravel to 30 minutes in fine- to medium-grained sand.

Groundwater sampling with the Waterloo Profiler is not recommended for

lithology with sediments finer than fine-grained sands because of the lengthy

sampling time required.

$SSOLFDWLRQV DQG &RVW

The Waterloo Profiler is a useful tool for

rapid vertical profiling of hydrostratigraphy

down to a maximum of 100 feet bgs. (Actual

maximum depth is dependent on sitespecific conditions and is typically shallower

than 100 feet). The tool allows for

delineation of contaminants in highly

stratified formations where

microstratigraphy plays a significant role in

contaminant migration.

The cost of the Waterloo Profiler plus directpush rig adds approximately $1,600 per day

to total sample collection costs. Sampling

depth and frequency, site hydrostratigraphy,

and buried obstructions can have significant

impact on the tool’s effectiveness.

%HQHILWV

 Allows multiple depth-discrete groundwater sampling in a single borehole

(i.e., sampler does not have to be withdrawn between samples)

 Less prone to cross-contamination than multiple pushes with conventional

push sampler
&KDSWHU 

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4-20

 Can be used with field instruments to screen for volatile organic compounds

while pushing

 Field tested and proven

 Allows for delineation of contaminant pathways in microstratigraphy

/LPLWDWLRQV

 Profiler available only through a limited number of vendors

 Limited by depth to which the sampler can be pushed/driven

 Shallow groundwater sampling via peristaltic suction-lift pump may cause

volatilization of some contaminants during sampling

 Groundwater sample collection recommended only for fine-grain sands and

coarser materials

 0XOWL/HYHO *URXQGZDWHU 6DPSOHUV

Multi-level groundwater samplers are used to collect groundwater samples at

multiple, discrete levels within a single monitoring well. These types of

groundwater samplers are equivalent to a series of nested monitoring wells but

require only one casing in a single borehole.

The tools discussed below include several types of multi-level groundwater

samplers:

 Westbay System

 Waterloo System

 Diffusion Multi-Layer Sampler (DMLS)

 :HVWED\ 6\VWHP

7RRO 'HVFULSWLRQ

The Westbay System is a fixed, multi-level sampler built for installation in a multiport monitoring well. It is designed to collect groundwater samples and hydraulic

head measurements at multiple, discrete levels in a single monitoring well. Multiport monitoring wells are like a series of nested monitoring wells but require only

one casing in a single borehole. The Westbay System incorporates valved

couplings, casings, and permanently inflated packers into a single instrumentation

string that is installed inside a cased borehole with multiple screened intervals,

allowing multi-level groundwater monitoring for a fraction of the installation cost

of nested monitoring wells.
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4-21

The following figure shows the typical design detail for a Westbay System multiport monitoring well. 

2SHUDWLRQDO

&RQVLGHUDWLRQV

Westbay System multi-port

monitoring systems are

complex and require

trained technicians to

install. Monitoring wells

must be designed

specifically to conform with

the Westbay System

requirements. Field quality

control procedures enable

verification of the quality of

the well installation and

operation of the testing and

sampling equipment.

Groundwater samples from

Westbay monitoring wells

are collected without

repeated purging. In

addition, Westbay is

currently developing

instruments to enable the

use of in situ sensors to monitor various chemical parameters.

$SSOLFDWLRQV DQG &RVW

The Westbay System is useful for MGP sites where multiple groundwater zones

exist and discrete monitoring of multiple screened zones is required. 

One of the primary cost savings with the Westbay System is that several discrete

groundwater zones can be sampled by installing only one well. Fewer boreholes

mean lower drilling costs, a shorter project schedule, and less IDW (e.g., drill

cuttings and fluid). This can result in substantial savings in waste management,

site access approval, noise abatement, and project management. In addition, fluid

samples are collected from the Westbay monitoring wells without repeated

purging (the groundwater in each zone is not in contact with the atmosphere),

which can lead to significant cost reductions at sites where purge water must be

stored, transported, and treated before disposal. The cost of installing a Westbay

System is approximately $30,000 for a five-level system that can range from 50 to

200 feet in depth. The price does not include the cost of installing the monitoring

well and does not include sample collection or analysis. 

%HQHILWV

 Reduces the amount of drilling
&KDSWHU 

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4-22

 Provides reliable data

 Field tested and proven

/LPLWDWLRQV

 Mechanically complex

 Requires well construction to specific Westbay specifications

 Not portable between wells

 :DWHUORR 6\VWHP

7RRO 'HVFULSWLRQ

The Waterloo System is used to obtain groundwater samples, hydraulic head

measurements, and permeability measurements from multiple isolated zones in a

single monitoring well. The Waterloo System uses modular components held

firmly together to form a sealed casing string composed of casing, packers, ports, a

base plug, and a surface manifold. Monitoring ports are isolated by packers at each

desired monitoring zone and are individually connected to the surface manifold

with narrow-diameter tubing. Formation water enters the port, passes into the

stem, and rises to its static level in the monitoring tube attached to the stem. A

sampling pump or pressure transducer may be dedicated to each monitoring zone

by attachment to the port stem, or the monitoring tubes may be left open to allow

sampling and hydraulic head measurements with portable equipment. A section

of the sampler is shown in the following figure.

2SHUDWLRQDO &RQVLGHUDWLRQV

A typical Waterloo System can be

installed in a few hours by one trained

technician and an assistant. Purge

volumes are small, and dedicated

pumps for all zones can be purged

simultaneously. Because the

groundwater in each zone is not in

contact with the atmosphere, formation

water may be sampled without repeated

purging. The Waterloo System may be

used in hollow-stem augers, temporary

casing, or cased and screened wells.

$SSOLFDWLRQV DQG &RVW

The Waterloo System is useful for MGP

sites with multiple groundwater zones

when discrete monitoring of the zones is

required. Project costs may be reduced

by limiting the number of wells
&KDSWHU 

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4-23

installed and maximizing the number of groundwater zones sampled. The purge

volumes necessary for groundwater sampling using the Waterloo System are

likely to be smaller than those from conventional nested monitoring wells.

The cost of installing the Waterloo System is approximately $25,000 for a five-level

system that can range from 50 to 200 feet in depth. This price does not include the

costs of monitoring well installation or sample collection or analysis.

%HQHILWV

 Reduces the number of wells needed for multiple-zone monitoring

 Reduces purge volumes and may reduce time required for purging/sampling

relative to conventional monitoring well requirements

 Provides reliable data

 Removable or permanent systems available

/LPLWDWLRQV

 Mechanically complex

 Specially ordered materials necessary

 Removable packer system sometimes difficult to cost-effectively reuse

 Requires trained technician for installation

&RQWDFW

Solinst Canada Ltd., (800) 661-2023, www.solinst.com

 'LIIXVLRQ 0XOWL/D\HU 6DPSOHU '0/6

7RRO 'HVFULSWLRQ

DMLS TM is portable, multi-layer device that can collect groundwater samples at

multiple intervals in the same monitoring well. The DMLS TM uses dialysis cells

separated by seals that fit the inner diameter of the well. This arrangement allows

natural diffusion of groundwater into the unit at different elevations. Once the

DMLS TM is lowered into either an open rock borehole or a groundwater

monitoring well with a long screen, the dialysis cells are exposed to water in the

borehole and natural diffusion gradients permit external formation water to reach

equilibrium with the water in the dialysis cells. The water flowing from the

formation into the stratified dialysis cells is separated by seals; therefore, each

dialysis cell contains a groundwater sample from a different layer. 

The basic unit of the DMLS TM is a 5-foot-long polyvinyl chloride (PVC) rod with a

variable number of dialysis cells and nylon membranes separated from each other

by seals. A string of up to five rods can be formed. Vertical layers of groundwater

as narrow as 3 inches can be segregated and sampled. The rods fit into 2-inchdiameter and larger wells.
&KDSWHU 

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4-24

The following figure shows the typical design detail for a DMLS TM multi-level

groundwater sampler.

2SHUDWLRQDO &RQVLGHUDWLRQV

Once the DMLSTM is lowered into a well, it should remain undisturbed for 7 to 10

days to allow stratification of the water flowing from the formation. Once

stratification of the formation water is complete and

the water in the sampling cells is representative of

ambient conditions, the rods are pulled to the surface

and the sampling cells are removed and sent to a

laboratory for analysis. The sampling cells in the rods

can then be replaced, and the process can be

repeated. The DMLSTM may be left in the water for

periods of time that conform to individual sampling

schedules. For example,DMLSTM sampling cells may

be collected and replaced every three months. 

Because the DMLSTM relies on natural groundwater

diffusion principles, no purging is required. The

DMLSTM does not permit head measurements.

$SSOLFDWLRQV DQG &RVW

The DMLSTM is useful for MGP sites where

monitoring wells have long screens and a vertical

characterization of the screened aquifer is desired.

The DMLSTM reduces costs because several vertical groundwater zones can be

sampled by installing only one well. Having fewer boreholes reduces drilling

costs, shortens project schedules, and produces less secondary waste (e.g., drill

cuttings and fluid). The result is substantial cost savings in waste management,

site access approval, noise abatement, and project management. Groundwater

samples are collected from DMLSTM monitoring wells without repeated purging

(the groundwater in each zone is in direct contact with the formation water),

which can significantly reduce costs at sites where purge water must be stored,

transported, and treated before disposal. 

The cost of the DMLSTM is approximately $3,000 for a 10-foot-long unit. The price

does not include labor costs for installing the DMLSTM rods, nor does it include

costs for sample collection or analysis. 

%HQHILWV

 Allows vertical characterization of groundwater in a single borehole or well 

 Requires minimal training for installation

 Requires no purging

/LPLWDWLRQV

 Not widely used
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4-25

 Does not permit head measurements

 May not be appropriate for zones with strong vertical gradients

 'LVFUHWH 3RLQW 6DPSOHUV

7RRO 'HVFULSWLRQ

Floating product layers (e.g., LNAPL) or sinking product layers (e.g., DNAPL)

may cause stratification of contaminant concentrations in groundwater. Discrete

point samplers are used to represent groundwater at distinct elevations or points

of inflow in either open boreholes or screened wells. Discrete point samplers are

designed to minimize disturbance and/or mixing that would be caused by

pumping and purging water from different zones. 

Several tools are available that have been designed to collect groundwater samples

at discrete points in either open boreholes or in screened wells. Solinst Canada,

Ltd., manufactures a number of samplers designed for use in wells screened over

multiple water-bearing zones. Two examples are the Model 429 Point Source

Bailer and the Model 425 Discrete Interval Sampler. The Model 429 Point Source is

a stainless steel bailer with dual ball valves that prevent the mixing of water from

multiple depths during retrieval of a sample from a specific depth. The Solinst

Model 425 Discrete Interval sampler (shown in the figure below) is a stainless steel

sampler connected by tubing that is pressurized before the device is lowered into a

well; pressurization prevents water from

entering the sampler until the sampling zone

is reached. When the desired sampling depth

is reached, pressure is released, and

hydrostatic pressure fills the sampler and

tubing with water directly from the

sampling zone. When the sampler is filled, it

is repressurized and raised to the surface; the

sample is decanted using the sample release

device provided, which avoids degassing of

the sample (Solinst, 1998).

Solinst also manufactures a Triple Tube

Sampler that uses a narrow-diameter pump

and packer assembly to seal off a discrete

interval in groundwater. A nitrogen-inflated packer is placed just above the

desired sampling point within the sampling tube. The packer seals against the

walls of the sampling tube and isolates the formation water standing in the tube. A

second nitrogen line applies pressure down the sampling tube. The water is

pushed to the surface through the coaxial tubing. The cycle is repeated until

purging and sampling are complete. 

The Solinst Triple Tube Sampler is similar to the Waterloo Profiler multi-level

groundwater sampler discussed in Section 4.2.1.5 except that the Solinst sampler is

designed to sample from wells whereas the Waterloo Profiler is a direct-push
&KDSWHU 

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4-26

sampler designed to collect grab groundwater samples without boreholes or wells

(Solinst, 1998).

2SHUDWLRQDO &RQVLGHUDWLRQV

The Solinst Model 429 Point Source Bailer and the Solinst Model 425 Discrete

Interval Sampler do not require or allow purging prior to sampling. It is assumed

that a sample collected at a discrete depth is representative of the formation water

flowing through the well at that depth. The Solinst Triple Tube Sampler does

permit purging of the discrete interval being sampled.

$SSOLFDWLRQV DQG &RVW

Discrete point samplers are useful for field scenarios where heterogeneities exist in

the vertical distribution of contaminant concentrations in groundwater in an open

borehole or screened well. 

The purchase costs for Solinst Model 429 Point Source Bailer, Solinst Model 425

Discrete Interval Sampler, and the Solinst Triple Tube Sampler are approximately

$150, $675, and $2,000, respectively.

%HQHILWV

 Permits groundwater sampling from a discrete vertical point in a well or

borehole

 Minimizes mixing of water from different levels during sample collection

 Fits in small-diameter wells/boreholes

 Is portable (the Triple Tube Sampler may be dedicated)

 Solinst Triple Tube Sampler is usable for purging in addition to sampling

/LPLWDWLRQV

 May require limited training to operate equipment (especially the Triple Tube

Sampler)

 May be difficult to obtain a complete seal with the Solinst Triple Tube Sampler

&RQWDFW

Solinst Canada Ltd., (800) 661-2023, www.solinst.com

%&
'	
		

Field screening tools allow practitioners to detect the presence and determine the

estimated concentrations of chemical constituents in the field. As noted above,

combining these tools with direct-push grab sampling techniques allows rapid and

cost-effective preliminary screening of former MGP sites by pinpointing areas of

contamination that require further, focused field investigations. Once these areas

are identified, field screening tools can be used to gather further data so that 
&KDSWHU 

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4-27

remediation alternatives can be evaluated. In some cases, the tools can also be used

to gather confirmatory data during remediation. 

Tools included in this category are:

 Laser Induced Fluorescence (LIF) (such as ROSTTM)

 X-ray fluorescence (XRF) (such as the Spectrace 9000, SEFA-P, or X-MET 880)

 Colorimetric testing (such as Hach Kits, Draeger Tubes, Sensidyne, Handby

Kits, PetroSenseTM, and PetroFLAGTM)

 Immunoassay testing (such as Strategic Diagnostics)

 Portable laboratories

 5DSLG 2SWLFDO 6FUHHQLQJ 7RRO 5267

7RRO 'HVFULSWLRQ

The ROSTTM is a sampling and screening technology used to field screen for

petroleum hydrocarbons and other contaminants. Like its military sister, the

SCAPS, ROSTTM is designed to offer a suite of CPT tools on a single platform.

Using fiber-optic technology with LIF, ROSTTM provides rapid, real-time, in situ

delineation of subsurface petroleum hydrocarbon contamination down to depths

of 150 feet. 

The ROSTTM consists of a sensor-tipped, hydraulically advanced, penetrometer

probe with a self-contained data collection and analysis system housed within a

CPT truck. Additional probes incorporate video imaging technology and soil

moisture measurements while the latest CPT sampling devices allow for the

collection of soil, water, or gas samples with analytical confirmation or other

measurements. A diagram of ROSTTM/SCAPS is shown in the figure on the

following page.

2SHUDWLRQDO &RQVLGHUDWLRQV

Operational considerations with ROSTTM sampling technology are similar to those

of cone penetrometers. Depths are limited to 100 to 150 feet bgs in normally

consolidated soils, shallower in coarser materials. The ROSTTM sampling

technology does not produce soil cuttings and can provide real-time, in situ field

screening for petroleum hydrocarbons. The ROSTTM can also detect small

deviations in concentrations, thereby making it useful in mapping areas with

significant subsurface structures/materials. Microwells can also be installed using

this tool.

$SSOLFDWLRQV DQG &RVW

The ROSTTM sampling technology is useful for field surveys and initial

characterization of sites, and for post-remediation confirmation for petroleum

hydrocarbons. The system is limited to the depths of the CPT and by the sensors

currently available.
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4-28

ROSTTM costs approximately $4,000 to $4,500 per day with production up to 300

feet (around 10 pushes) per day.

%HQHILWV

 Provides rapid, real-time geology and hydrocarbon data

 Can be used to converge on an area of interest

 Works for both fuel (aromatic) hydrocarbons and PAHs

 Generates little waste during testing/sampling

 Verified by USEPA and certified by California EPA

/LPLWDWLRQV

 Limited availability (only two commercial licenses currently held)

 Limited to unconsolidated geology (same as CPT)

 Only relative concentration data provided

&DVH 6WXG\

1RUWK &DYDOFDGH 6XSHUIXQG 6LWH +RXVWRQ 7H[DV

The North Cavalcade Street Superfund Site is a former wood treating facility,

located in northeastern Houston, Texas. The site encompasses approximately 21

acres, and was used for treating wood from 1946 to 1964. Initially, creosote was

employed as the primary wood preservative, but later operations also included