ArticlePDF Available

Recommendations To Improve the Cleanup Process for California's Leaking Underground Fuel Tanks (LUFTs)

December 1995

December 1995

Authors:

Brendan Dooher

PG&E

Stephen Cullen

Daniel B. Stephens & Associates, Santa Barbara, CA

Show all 14 authorsHide

This document summarizes the findings, conclusions, and recommendations resulting from an 18 month review of the regulatory framework and cleanup process currently applied to California's leaking underground fuel tanks (LUFT). This review was conducted by the Lawrence Livermore National Laboratory (LLNL) and the University of California at Berkeley, Davis, Los Angeles, and Santa Barbara at the request of the State Water Resources Control Board (SWRCB), Underground Storage Tank Program. The recommendations are made to improve and streamline the LUFT cleanup decision-making process.

Content uploaded by William Kastenberg

Content may be subject to copyright.

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

UCRL-AR-121762

Recommendations To Improve the

Cleanup Process for California’s

Leaking Underground Fuel Tanks

(LUFTs)

Authors

David W. Rice

Brendan P. Dooher*

Stephen J. Cullen**

Lorne G. Everett**

William E. Kastenberg***

Randolph D. Grose****

Miguel A. Marino****

Submitted to the California State Water Resources Control Board

Underground Storage Tank Program and the

Senate Bill 1764 Leaking Underground Fuel Tank Advisory Committee

October 16, 1995

* University of California, Los Angeles

** University of California, Santa Barbara

*** University of California, Berkeley

**** University of California, Davis

Environmental Protection Department

Environmental Restoration Division

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

iii

Acknowledgments

A number of dedicated individuals have contributed to the research and preparation of these

recommendations. The authors would like to thank the following individuals for their dedication,

expertise, and hard work that made this project successful.

R. Depue

D. Gresho

C. Kuks

N. Prentice

R. Ragaini

D. Schmidt

J. Yow

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

Contents

Executive Summary .................................................................................................................. EX-1

1. Introduction................................................................................................................................ 1

2. Methods...................................................................................................................................... 1

3. Background ................................................................................................................................ 2

3.1. Regulatory Framework ................................................................................................. 2

4. Findings...................................................................................................................................... 4

4.1. LUFT Impacts to Groundwater Resources ................................................................... 4

4.1.1. Impacts to Public Water-Supply Wells ..................................................... 4

4.1.2. LUFT FHC Impacts to Drinking Water Wells......................................... 4

4.1.3. Use of Well Construction Standards ........................................................ 5

4.1.4. Volume of Groundwater Affected by LUFT FHCs ................................. 5

4.2. Derivation of LUFT Cleanup Requirements ................................................................ 6

4.2.1. Groundwater............................................................................................. 6

4.2.2. Soils.......................................................................................................... 6

4.3. Application of LUFT Regulatory Framework and Cleanup

Requirements ...................................................................................................... 7

4.3.1. Groundwater............................................................................................. 7

4.3.2. Soils.......................................................................................................... 8

4.3.3. Data Collection......................................................................................... 9

4.4. Technical Feasibility..................................................................................................... 9

4.4.1. Passive Bioremediation .......................................................................... 10

4.4.2. Actively Engineered Remediation—Pump and Treat ............................ 11

4.5. Economic Impact of Current LUFT Problem............................................................. 12

4.5.1. Lack of Financial Incentives ................................................................... 12

4.5.2. UST Cleanup Costs ................................................................................ 13

4.5.3. The Value of Groundwater..................................................................... 13

4.6. Applicability of Risk-Based Corrective Action (RBCA) to LUFT

Decision Making............................................................................................... 14

4.6.1. Systematized Site Evaluation and Selection of Cleanup

Requirements................................................................................... 14

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

4.6.2. Broad, Systematic Decision-Making Approach That Can

Be Adopted at the State Level, but Permits Local

Implementation................................................................................ 14

4.6.3. Decision-Making That is Technically Defensible and

Strongly Supported.......................................................................... 15

4.6.4. Continuous Access and Utilization of Data for Decision

Making............................................................................................. 15

5. Conclusions.............................................................................................................................. 15

5.1. Fuel Hydrocarbons (FHCs) Have Limited Impacts on Human Health

or the Environment ........................................................................................... 15

5.2. The Cost of Cleaning Up Leaking Underground Fuel Tank (LUFT)

Fuel Hydrocarbons (FHCs) is Often Inappropriate When

Compared to the Magnitude of the Impact of California's

Groundwater Resources.................................................................................... 16

5.3. LUFT Groundwater Cleanup Requirements Are Derived from Policies

That Are Inconsistent with the Current State of Knowledge and

Experience ........................................................................................................ 16

5.4. Current Understanding of FHC Fate and Transport Processes in the

Subsurface Environment Is Not Reflected in the Present LUFT

Cleanup Process................................................................................................ 17

5.5. There Are Few Situations Where Pump and Treat Should be

Attempted ......................................................................................................... 17

5.6. A Risk-Based Corrective Action (RBCA) Framework Offers a

Common Decision-Making Process To Systematically Address

LUFT Cleanup .................................................................................................. 17

5.7. Modifications Would Be Necessary for the ASTM RBCA Framework

To Be Used in California.................................................................................. 18

5.8. A Common, Systematic Decision-Making Process Using Standard

Procedures Will Reduce Inconsistencies in Soils Cleanup

Requirements .................................................................................................... 19

5.9 Total Petroleum Hydrocarbon (TPH) Measurements Should Not be

used to Predict Benzene Concentrations........................................................... 19

6. Recommendations.................................................................................................................... 19

6.1. Utilize passive bioremediation as a remediation alternative whenever

possible. ............................................................................................................ 19

6.2. Immediately modify and implement an ASTM RBCA framework to

allow streamlined closure criteria that.............................................................. 19

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

6.3. Apply a modified ASTM RBCA framework as soon as possible to

LUFT cases where FHCs have affected soil but do not threaten

groundwater. ..................................................................................................... 20

6.4. Modify the LUFT regulatory framework to allow consideration of

risk-based cleanup goals higher than MCLs..................................................... 20

6.5. Identify a series of LUFT demonstration sites and form a pilot LUFT

closure committee............................................................................................. 20

References................................................................................................................................... R-1

Acronyms

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

vii

Executive Summary

This document summarizes the findings, conclusions, and recommendations resulting from

an 18 month review of the regulatory framework and cleanup process currently applied to

California's leaking underground fuel tanks (LUFT). This review was conducted by the

Lawrence Livermore National Laboratory (LLNL) and the University of California at Berkeley,

Davis, Los Angeles, and Santa Barbara at the request of the State Water Resources Control

Board (SWRCB), Underground Storage Tank Program. The recommendations are made to

improve and streamline the LUFT cleanup decision-making process.

Findings

LUFT Impacts to Groundwater Resources

Out of 12,151 public water-supply wells tested statewide, only 48 (0.4%) were reported to

have measurable benzene concentrations. A review of the state's database of 28,051 LUFT cases

shows that 136 LUFT sites (0.5%) have reportedly affected drinking water wells. Most of the

affected wells are shallow private domestic wells in close proximity to the LUFT release site.

The total potential volume of groundwater impacted by LUFT plumes greater than 1 part per

billion (ppb) benzene was estimated to be 0.0005% of California’s total groundwater basin

storage capacity.

Groundwater cleanup policies are not applied to many sources of groundwater contamination

because well construction standards have proven to be protective, it is not practical to regulate

some types of sources, and the contaminants typically undergo rapid degradation in the

subsurface.

Derivation of LUFT Cleanup Requirements

Under current regulations and policies, the minimum cleanup standards for LUFT cases

affecting groundwater are the maximum contaminant levels (MCLs) for drinking water. Numeric

cleanup standards are not established for residual fuel hydrocarbons (FHCs) in soil.

Application of LUFT Regulatory Framework and Cleanup Requirements

Even though there is a widely voiced complaint that the LUFT corrective action process is

inconsistently applied, groundwater cleanup standards and soils cleanup guidance are consistent

with the Water Code and SWRCB resolutions.

Groundwater cleanup requirements were found to be consistently applied statewide due to the

presence of numerical standards. These groundwater cleanup requirements do not permit

balancing of considerations of technical and economic feasibility, and protection of human

health, the environment, and beneficial water uses as required by the Water Code.

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

viii

While soils cleanup guidance is consistent with SWRCB resolutions, actual soils cleanup

requirements vary in practice because there are no numeric standards.

Technical Feasibility

If a FHC source is removed, passive bioremediation processes act to naturally reduce FHC

plume mass and to eventually complete the FHC cleanup. Benzene plume lengths tend to

stabilize at relatively short distances from the FHC release site. Remediation alternatives that

utilize pump and treat are recognized as being ineffectual at reaching MCL groundwater cleanup

standards for FHCs in many geologic settings. Passive bioremediation can provide a remediation

alternative that is as efficient as actively engineered remediation processes such as pump and

treat.

Economic Impact of Current LUFT Problem

The current LUFT decision-making process does not result in cost-effective site closures, in

part, because financial incentives to support this result do not exist for cases in the UST Cleanup

Fund. The average cost of each LUFT case cleanup is $150,000. The overall fiscal effect of

ongoing and future LUFT cleanups on the California economy can be estimated to be about

$3 billion. About $1.5 billion will be raised by the time the UST Cleanup Fund storage fee ends

in 2005. The current policies and regulations value FHC affected groundwater at about $637,000

per acre-foot.

Applicability of Risk-Based Corrective Action (RBCA) to LUFT Decision

Making

A statewide, consistently applied RBCA decision-making framework will allow regulators

and responsible parties (RPs) to know where they are in the decision-making process and what

steps to take next. A RBCA approach to LUFT cleanups will provide guidance to reasonably

manage risks to human health, ecosystems, and groundwater beneficial uses while considering

technical and economic feasibility. The recently developed American Society for Testing and

Materials (ASTM) RBCA framework offers a promising tiered decision-making approach to

LUFT cleanups.

Conclusions

Fuel hydrocarbons (FHCs) have limited impacts on human health, the environment, or

California’s groundwater resources. Where shallow groundwater has been impacted by LUFT

FHCs, well construction standards provide protection of deeper drinking water wells. The costs

of cleaning up LUFT FHCs are often inappropriate when compared to the magnitude of the

impact on groundwater resources.

LUFT groundwater cleanup goals are derived from policies that are inconsistent with the

current state of knowledge and experience. Since the LUFT Manual was prepared, the

understanding of FHC fate and transport processes in subsurface environment has increased and

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

new understanding of passive bioremediation processes is not reflected in the present LUFT

cleanup process. There are few situations where pump and treat should be attempted.

The State Water Resources Control Board (SWRCB) policies that set groundwater cleanup

requirements to MCLs or background are a barrier to setting risk-based groundwater cleanup

goals and closing LUFT cases based on an evaluation of risk to human health and the

environment.

A RBCA framework offers a common decision-making process to systematically address

LUFT cleanup and reduce inconsistencies. In order for the ASTM RBCA framework to be used

in California, modification would be necessary. This modified ASTM RBCA approach can

incorporate the results of the SWRCB's historical LUFT case analysis to reflect California’s site-

specific exposure parameters, as well as quantify the uncertainty in the assumptions that are used

during risk evaluations. In addition, a modified ASTM RBCA tiered, decision-making approach

will allow the formulation of streamlined closure criteria that can encompass a majority of

California's LUFT cases.

Recommendations

Utilize passive bioremediation as a remediation alternative whenever

possible

Minimize actively engineered LUFT remediation processes. Once passive bioremediation is

demonstrated and unless there is a compelling reason otherwise, close cases after source removal

and rely on passive bioremediation to cleanup FHCs. In general, do not use the UST Cleanup

Fund to implement pump and treat remediation unless its effectiveness can be demonstrated.

Immediately modify the ASTM RBCA framework based on California

historical LUFT case data

Perform LUFT historical case studies on soils-only cases to support development of a RBCA

tier-one decision-making process. Use LUFT historical case data to modify ASTM RBCA to

reflect California’s site-specific exposure pathways and quantify the uncertainty in the

assumptions that are used during risk evaluations. The modified ASTM RBCA tier-one decision-

making process should encompass a majority of California’s LUFT cases and facilitate and

encourage the utilization of passive bioremediation.

Apply a modified ASTM RBCA framework as soon as possible to LUFT

cases where FHCs have affected soil but do not threaten groundwater

There are no existing barriers to implementing ASTM RBCA at LUFT sites where FHCs

have only affected soils.

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

Modify the LUFT regulatory framework to allow the consideration of risk-

based cleanup goals higher than MCLs

Modify SWRCB policies to remove barriers to applying a modified ASTM RBCA

framework to FHCs affecting groundwater. Once SWRCB policy barriers have been removed,

apply ASTM RBCA process to LUFT cases where FHCs have affected groundwater.

Identify a series of LUFT demonstration sites and form a pilot LUFT

closure committee

LUFT demonstration sites should be chosen to:

• Act as training grounds for implementation of a modified ASTM RBCA process.

• Facilitate the implementation of a revised LUFT decision-making process.

• Test recommended sampling and monitoring procedures and technologies to support

passive bioremediation.

• Confirm cost effectiveness of the modified ASTM RBCA process.

A pilot LUFT closure committee, made up of scientific professionals from universities,

private industry, and state agencies, should be set up to make professional interpretations and

recommendations regarding LUFT evaluations and closures at the demonstration sites.

1. Introduction

In July 1994, the California State Water Resources Control Board (SWRCB) Underground

Storage Tank (UST) Program embarked on a reevaluation of the Leaking Underground Fuel

Tank (LUFT) cleanup procedures. To support this effort, the SWRCB UST Program contracted

with the Lawrence Livermore National Laboratory (LLNL) and the University of California at

Berkeley, Davis, Los Angeles, and Santa Barbara to form a team of scientific experts (the UC

LUFT Team) to review the existing LUFT cleanup decision-making process and submit

recommendations for improvement.

This review was a collaborative effort among the SWRCB

staff, LLNL, and UC LUFT Team members. Financial support for this effort was provided, in

part, by the U.S. Environmental Protection Agency (EPA), Region IX, UST Program.

The objective of this collaborative research was to evaluate the present regulatory framework

of the SWRCB and regional water quality control boards (RWQCBs) and to recommend any

revisions necessary to streamline the petroleum UST site investigation and cleanup decision-

making process to protect human health and the environment. This revised decision-making

process would allow consideration of (1) the application of natural passive bioremediation

processes to fuel hydrocarbons (FHCs), (2) eventual land use, and (3) existing and probable

beneficial uses of water resources during the remediation process. Emerging characterization and

monitoring technologies would also be recommended to support a revised LUFT cleanup

decision-making approach.

In conjunction with the SWRCB review of the LUFT cleanup procedures, the California state

legislature instituted Senate Bill 1764 (SB 1764, Thompson), which required the SWRCB to

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

form a separate scientific committee to review the LUFT cleanup procedures and make

recommendations to the legislature for any necessary changes. As part of SB 1764 committee’s

proceedings, the views of industry trade groups, consultants, contractors, impacted parties,

environmental groups, and regulators were solicited through a request for white papers that

address problems in the existing LUFT cleanup process and propose recommendations for

improvement.

2. Methods

During the UC LUFT Team’s research, available information was thoroughly evaluated to

establish appropriate state-of-the-art approaches pertaining to:

• Current LUFT decision-making procedures and regulatory framework.

• Environmental fate and transport of petroleum constituents in soil, the vadose zone, and

groundwater.

• Applicable LUFT cleanup characterization and monitoring technologies.

This evaluation included information available from:

• Extensive searches of scientific literature.

• U.S. EPA, Office of Underground Storage Tanks.

• American Petroleum Institute.

• American Society for Testing and Materials (ASTM).

• Council for the Health and Environmental Safety of Soil.

• U.S. Air Force Center for Environmental Excellence.

• Researchers working on Department of Energy efforts to deal with soil and groundwater

contamination.

In addition, the UC LUFT Team reviewed the numerous white papers submitted to the SB 1764

LUFT committee.

As a precursor to developing decision-making approaches, the UC LUFT Team identified the

decisions and characterization parameters that are necessary to implement a LUFT corrective

action, including the selection of an appropriate remediation method. The parameters affecting

the environmental fate of FHCs that were considered included the physical and chemical

properties of soil, groundwater, and petroleum products, and subsurface microbiological

activities.

A major component of the LUFT reevaluation effort was a case file analysis of more than

1,500 LUFT cases reported between 1985 and 1995. This LUFT historical case analysis was

used to evaluate the FHC plume impacts on groundwater resources, behavior and factors that

influence plume length and mass, and adequacy of historically collected decision-making data.

This information was used during the evaluation of criteria for determining when remediation

had been satisfactorily completed, the cleanup requirements for responsible parties (RPs), and the

policies, guidelines, and methods that are used to establish those requirements. The UC LUFT

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

Team assisted the SWRCB in preparing the data-gathering procedures and database structure,

identifying important questions to be asked of the resulting database, performing statistical

analysis of the data, and integrating the data analysis results into a final report (Rice et al., 1995).

3. Background

3.1. Regulatory Framework

California USTs are regulated through a framework of laws, regulations, and state, regional,

and local policies. The California Water Code is the law from which regulations and policies are

derived. SWRCB resolutions are policies used to implement the Water Code. SWRCB

resolutions are prepared though a public hearing process and consideration of the current state of

knowledge and experience.

The Porter–Cologne Water Quality Control Act, Chapter 1 (commencing with Section

13000), Division 7, of the California Water Code, stipulates to state and regional water boards

that “… those activities and factors (that) may affect the quality of the waters of the state shall be

regulated to attain the highest water quality which is reasonable; considering all demands being

made and to be made on those waters and the total values involved, beneficial and detrimental,

economic and social, tangible and intangible ….”

Because different regions have a range of hydrogeologic settings and water management

practices and uses, the SWRCB and RWQCBs are required by law to manage the state’s water

resources through a policy that considers “... factors of precipitation, topography, population,

recreation, agriculture, industry and economic development (that) vary from region to region

within the state, and that the statewide program can be most effectively administered regionally,

within a framework of statewide coordination and policy (California Water Code, Chapter 1,

Section 13000, Division 7).”

The RWQCBs develop Regional Basin Plans to establish the present and probable beneficial

uses of water within their regions, and these plans are subject to State Board policies during the

formulation of water quality objectives and beneficial uses. According to Section 13241 of the

California Water Code, the factors that RWQCBs should consider in setting water quality

objectives “... shall include, but not necessarily be limited to, all of the following:

a) past, present, and probable future beneficial uses of water,

b) environmental characteristics of the hydrographic unit under consideration, including the

quality of water available thereto,

c) water quality conditions that could reasonably be achieved through coordinated control of

all factors which affect water quality in the area,

d) economic considerations,

e) the need for developing housing in the region, and

f) the need to develop and use recycled water.”

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

In 1983, California began to regulate USTs containing FHCs, such as gasoline, diesel fuel,

and fuel oils, in response to a perceived threat to the state’s groundwater resources. A 1984

survey showed that there were approximately 200,000 USTs within the state.

California Underground Storage Tank Regulations were promulgated in 1985 by the

SWRCB. According to these regulations, an RP is required to perform soil and groundwater

investigations if any of the following circumstances apply:

1. There is evidence that surface water or groundwater has been or may be affected by the

unauthorized release.

2. Free product is found at the site where the unauthorized release occurred or in the

surrounding area.

3. There is evidence that contaminated soils are or may be in contact with surface water or

groundwater.

4. The regulatory agency requests an investigation, based on the actual or potential effects

of contaminated soil or groundwater on nearby surface water or groundwater resources or

based on the increased risk of fire or explosion.

The California LUFT Field Manual was prepared in 1985 to address the regulatory problem

of a growing number of contaminated fuel sites. The document was created by a 38-member

LUFT Task Force, made up of a multiagency working group from the California Department of

Health Services (DHS) and from the SWRCB staff from both the state and regional levels. The

original LUFT Field Manual was last revised in 1989 (SWRCB, 1989).

The LUFT Field Manual procedures were intended to avoid unwarranted expense, analysis,

or delays, while ensuring that site characterization analysis is adequate for identifying the extent

of, and designing an appropriate response to, FHC soil contamination problems. The intended

users included regulators and environmental engineering consulting firms that assist RPs in

performing LUFT cleanups.

California is currently faced with about 21,000 active LUFT sites that must be evaluated to

manage potential threats to human health, the environment, and groundwater resources. LUFT

regulatory oversight is conducted by nine RWQCBs and 20 local oversight program (LOP)

regulatory agencies (19 counties and one water district) under contract with the SWRCB.

RWQCBs and LOP agencies are responsible for determining when cleanup requirements have

been met and LUFT cases can be closed.

4. Findings

4.1. LUFT Impacts to Groundwater Resources

4.1.1. Impacts to Public Water-Supply Wells

• Out of 12,150 public water-supply wells tested statewide, 48 were reported to have

measurable benzene concentrations.

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

The original LUFT Field Manual was prepared in an atmosphere of concern about “time

bomb plumes.” The capacity of the environment to naturally degrade FHCs was not recognized

or considered (P. Hadley, written communication to J. Giannopoulos, 1995). There was a

perception that with benzene in, or interconnected with, a usable aquifer, it was only a question

of time as to when benzene would reach a municipal or domestic water-supply well. However,

the weight of evidence is against this happening. A survey of well testing data from 7,167

California water-supply wells, during the period 1986–1989, found 10 water-supply wells

(0.1%) affected by benzene (Hadley and Armstrong, 1991). A more recent evaluation of well

testing data, during the period 1986–1995, indicates that out of more than 12,150 water-supply

wells, 48 (0.4%) were reported to have detectable benzene concentrations (K. Ward, written

communication to J. Giannopoulos, 1995). Of these, six (0.05%) could be attributed to LUFT

releases.

4.1.2. LUFT FHC Impacts to Drinking Water Wells

• A review of the state’s database of 28,051 LUFT cases shows that 136 LUFT sites have

reportedly affected drinking water wells.

• Most of the affected wells are shallow private domestic wells in close proximity to the

LUFT release site.

A review of the state’s database of 28,051 LUFT cases, which extends over 10 years and

includes both active and closed cases, shows that 136 LUFT sites have reportedly affected

drinking water wells (SWRCB LUSTIS, 1995). This represents less than 0.7% of the total

number of open LUFT cases. A recent review of 36 LUFT case files (R. Rempel, written

communication to J. Giannopoulos, 1995), which have reportedly affected 55 water-supply wells

in the Central Valley Region (RWQCB, Region 5), indicates that unreasonable impairment of

actual beneficial uses by benzene from LUFT sites is rare. Of the 55 reportedly affected wells, 25

could be attributed to LUFT releases. The impact to Region 5 water-supply wells from LUFT

FHCs constituted 0.3% of the total 5,871 LUFT sites in the region. Twenty-four of the 25

affected wells were private-domestic wells. Furthermore, the review found that 11 of the 24

affected private-domestic water-supply wells were the LUFT sites’ own shallow onsite wells.

The review concluded that the LUFT threats to groundwater resources should be evaluated based

on proximity and construction of water-supply wells within a few hundred feet of the LUFT site.

4.1.3. Use of Well Construction Standards

• Separation between known or suspected sources of pollution and contamination is

required during the siting and construction of water wells.

In addition to remediation, there are other ways that California prevents human and

ecological exposure to LUFT FHCs. Shallow groundwater is often degraded from a variety of

sources. California Well Standards outlined in California Department of Water Resources

Bulletins 74-90 and 74-81 (CDWR, 1991) indicate that separation between known or suspected

sources of pollution and contamination is required during the siting and construction of water

wells. In addition to above- and below-ground tanks and pipelines for the storage and

conveyance of petroleum products, sources of pollution and contamination identified by the

California Well Standards include: sanitary sewers; storm drains; septic tank leach fields; sewage

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

and industrial waste ponds; barn yard and stable areas; feedlots; solid waste disposal sites; and

storage and preparation areas for pesticides, fertilizers, and other chemicals.

Well construction and separation standards have been found to prevent exposure to many of

these contaminants and protective of human health and the environment. Groundwater cleanup

policies are not applied to many of these sources of groundwater contamination because well

construction standards have proven to be protective, it is not practical to regulate these sources,

and the contaminants typically undergo rapid degradation in the subsurface. The impact to the 11

on-site private-domestic water-supply wells affected by LUFT FHCs that were identified during

the review by R. Rempel (written communication to J. Giannopoulos, 1995) may have been

prevented by following the California Well Standards construction requirements.

4.1.4. Volume of Groundwater Affected by LUFT FHCs

• The total potential volume of groundwater impacted by LUFT plumes greater then 1 parts

per billion (ppb) benzene was 0.0005% of California’s total groundwater basin storage

capacity.

About 10,000 LUFT sites have reportedly affected groundwater. Using the historical LUFT

case analysis (Rice et al., 1995) plume lengths and widths, a conservative estimated total volume

of groundwater that may be impacted above a concentration of 1 ppb benzene was 7,060 acre-

feet. This volume of affected groundwater is 0.0005% of California’s total groundwater basin

storage capacity of 1.3 billion acre-feet.

4.2. Derivation of LUFT Cleanup Requirements

4.2.1. Groundwater

• Under current regulations and policies, the minimum cleanup standards for LUFT cases

affecting groundwater are the maximum contaminant levels (MCLs) for drinking water.

For FHC releases, the primary constituent of concern is benzene with a California MCL of

1 ppb. This groundwater cleanup standard for LUFT cases is required by SWRCB and RWQCB

adopted policies and plans as described below.

SWRCB Resolution 88-63, known as the Sources of Drinking Water Policy, requires a broad

application of the municipal (MUN) designation to groundwaters. Resolution 88-63 was adopted

in response to Proposition 65, which prohibited introduction of a carcinogen into any drinking

water source. The SWRCB determined that any aquifer that could produce over 200 gallons per

day and had less than 3,000 mg/L total dissolved solids would suffice as a “potential” source of

drinking water. As a result, with few exceptions, bodies of groundwater in the state are regulated

as MUN water quality. Availability of alternative sources of drinking water, cost of resource

development, threat of subsidence or salt water intrusion, and/or potential for contamination from

other sources are not considered (Fox, 1995). In many cases, cleanup is required even when

public utilities and residents in the area both agree that the water will never be utilized (Graves,

1995a; Earnest, 1995).

RWQCB basin plans specify MCLs as protective of groundwater with a MUN designation.

In California, these basin plans not only include the lowest MCLs in the nation, but also identify

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

taste and odor as secondary MCLs. For benzene, the California MCL is 1 ppb, with an MCL goal

of 0 ppb (nondetect). The U.S. EPA’s MCL for benzene is 5 ppb.

SWRCB Resolution 92-49 states that the setting of cleanup concentrations above background

shall not result in water quality less than that prescribed in adopted plans and policies, e.g., basin

plans. Therefore, the range of possible cleanup requirements for groundwaters is between MCL

and non-detect.

SWRCB Resolution 68-16, known as the Non-Degradation Policy requires that waters that

are of higher quality than the water quality objectives within a basin plan must be maintained at

the higher quality. Through the interpretation of this resolution, cleanup standards are broadly

applied to all points within a groundwater basin.

Resolution 68-16 also specifies that cleanup requirements assure that the highest water

quality consistent with the maximum benefit to the people of the state will be maintained.

Through Resolutions 88-63 and 92-49, the consideration of maximum benefit is limited to the

range between MCLs and non-detect for most groundwater basins in the state.

4.2.2. Soils

• Numeric cleanup standards are not established for residual FHCs in soil.

The flexibility in LUFT soils cleanup requirements is greater than groundwater cleanup

requirements. Numeric cleanup standards are not established for residual FHCs in soil. The

LUFT Field Manual deals with soils-only FHC contamination; it does not offer guidance to deal

with FHC plumes in groundwater because policies require groundwater cleanup to MCLs or

nondetect.

Because most LUFT cases have occurred in locations with shallow depth to groundwater,

there is a high probability of LUFT FHCs reaching groundwater. Gas stations and, therefore,

LUFT sites are concentrated in urban and suburban areas, which are typically associated with

layered, alluvial, hydrogeologic settings with a minimum depth to groundwater of 20 ft or less in

more than one-half of the cases (Rice et al., 1995).

The LUFT Field Manual was intended to provide practical guidance to regulatory agencies

and parties responsible for dealing with residual FHCs in soil associated with leaking fuel tanks.

The fate and transport of FHCs in the subsurface is complex, and the influence of unique site-

specific factors that influence FHC transport may be strong (Rice et al., 1995). Although the

LUFT Field Manual was initially considered to be among the best working documents for

dealing with subsurface FHC leaks, it has come under criticism in recent years as being

unrepresentative of statewide LUFT site hydrogeologic conditions. As a result, the actual use of

the LUFT Field Manual has been limited in California.

4.3. Application of LUFT Regulatory Framework and Cleanup

Requirements

4.3.1. Groundwater

• Groundwater cleanup standards are consistent with SWRCB resolutions.

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

• Groundwater cleanup requirements were found to be consistently applied statewide due

to the presence of numerical standards.

• These standards do not permit balancing of considerations of technical and economic

feasibility, and protection of human health, the environment, and beneficial water uses as

required by the Water Code.

There is a widely voiced complaint that the LUFT corrective action process is inconsistently

applied. However, during the LUFT Team’s research, groundwater and soils cleanup

requirements were found to be consistent with SWRCB policies. Groundwater cleanup

requirements were found to be consistently applied statewide due to the presence of numerical

standards, e.g., MCLs.

In practice, because it is impracticable to remove the last bit of residual FHC, drinking water

MCLs are often adopted as a more realistic cleanup target than the background concentrations

(nondetect) that Resolutions 68-16 and 92-49 would require. G. Torres (written communication,

1993) found that groundwater cleanup standards often default to drinking water supply action

levels or California MCLs for benzene (1 ppb), toluene (100 ppb), ethylbenzene (680 ppb), and

xylenes (1,750 ppb), as opposed to taste and odor thresholds. Sixty-five percent of the closed

groundwater-impacted cases were remediated to concentrations below the California MCL

cleanup standard.

While groundwater cleanup standards are consistent with SWRCB resolutions, however,

these standards are very restrictive and may be inappropriate. These requirements do not permit

the balancing of considerations of technical and economic feasibility, and protection of human

health, the environment, and beneficial water uses as required by the Water Code. Many cases

are difficult to close because the existing groundwater standards and goals are often technically

and economically infeasible and no systematic, statewide decision-making framework exists for

closing LUFT cases above MCLs.

4.3.2. Soils

• Soils cleanup guidance is consistent with the Water Code and SWRCB resolutions.

• Actual soils cleanup requirements vary in practice because there are no numeric

standards.

The current LUFT Field Manual guidance tables were developed using the one-dimensional

vadose zone transport simulation model, SESOIL. The LUFT guidance tables allow a cumulative

soil concentration of up to 1,000 ppm total petroleum hydrocarbons (TPH), sampled over 5-ft

intervals, with no sample concentration to exceed 100 ppm. This guidance is based on earlier

experiments performed in well sorted sands.

During the application of this model, the LUFT Field Manual creators made very

conservative assumptions about the factors controlling the transport of FHCs to groundwater and

regarded groundwater as the ultimate receptor. In practice, soil screening levels offered in the

LUFT Field Manual are not sufficiently representative of the diverse geology in California and

screening levels became “one-size-fits-all” action limits for determining if there is a threat to

groundwater.

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

A review of 110 closed LUFT case histories from the North Coast, San Francisco Bay, Los

Angeles, Central Valley, Santa Ana, and San Diego Regional Water Quality Control Boards by

the SWRCB Division of Clean Water Programs staff (G. Torres, written communication, 1993)

found that case closure criteria are often not clearly specified or consistently applied. Technical

rationale, upon which site cleanup and closure criteria for soil and groundwater are based, is

either lacking or inadequately documented. In lieu of cleanup standards grounded in a defensible

technical rationale, Torres found that the criteria used for site closure typically default to a soil

cleanup level of 100 ppm TPH, which is a screening level set in the LUFT Field Manual.

The Torres review indicated that 70% of the case closure requirements for soil-only impacted

sites were below soil concentrations of 100 ppm TPH. Cases where soil concentration goals

exceeding 100 ppm TPH were deemed acceptable included cases where underlying groundwater

had no beneficial use, high levels of total dissolved solids, or acceptably low BTEX (benzene,

toluene, ethyl benzene, xylene) concentrations over extended periods of monitoring. The closure

criteria implemented in the remaining closed cases cannot be determined due to the inadequate

documentation.

To address some of the perceived difficulties in the representativeness of the LUFT Field

Manual, a number of supplementary LUFT guidance documents have been provided at state

(SWRCB, 1992a; 1992b; 1993; 1994), regional (CRWQCB, 1993; 1994; 1995a; 1995b), and

local levels (Crowley, 1995). This has resulted in a complex regulatory structure that has been

inconsistently interpreted and applied across the state.

LOP and RWQCB staff make a variety of judgment calls regarding the determination of an

unauthorized release and the establishment of soils cleanup requirements. Action limits are often

inconsistently applied because different regulatory oversight programs do not think the limits are

representative or are either overly protective or not protective enough of local geologic settings.

Even within the same regulatory oversight agencies case workers are not consistent in their

decision-making process. One case worker may follow the letter of the LUFT Field Manual

guidance and use the general soil cleanup requirements, while another may make a more site-

specific determination of soil cleanup goals and relax the LUFT Field Manual action limits. The

inconsistencies in these judgment calls are the result of the different levels of knowledge and

experience of LUFT case handlers (Moran, 1995a). This causes different site owners with similar

problems to have very different remediation costs (Gustafson, 1995a, b).

4.3.3. Data Collection

• The level of detail, amount, and uses of data collected are not consistent among different

regulatory oversight agencies.

• Concerns have been raised concerning the validity of total petroleum hydrocarbon (TPH)

measurements .

The data to support LUFT decision-making processes is difficult to access and use. The

entire LUFT cleanup process revolves around reports submitted to regulatory agencies.

Unauthorized release reports, work plans, remedial investigation and quarterly monitoring

reports, and other special investigation results are all submitted during the normal course of a

LUFT cleanup. There is essentially no electronic filing of the information that is submitted

(Graves, 1995b).

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

Case records typically are maintained in paper copies. The Water Code endorses the need for

an information system to support water resource management. According to the Water Code,

Section 13166: “Information Program. The state board, with the assistance of the regional

boards, shall prepare and implement a statewide water quality information storage and retrieval

program. Such program shall be coordinated and integrated to the maximum extent practicable

with data storage and retrieval programs of other agencies.” Such a system exists only minimally

as a reporting tool to the U. S. EPA and is not used as a LUFT case decision-making tool.

Many current LUFT Field Manual decisions are based on the TPH-gasoline and TPH-diesel

concentrations in soil samples collected at the site. Concerns have been raised concerning the

validity of TPH measurements because many natural organic compounds can lead to false

positive results (Gustafson et al., 1995c) and because inconsistencies in the use of TPH analytical

methods make comparisons of results difficult (Clementsen, 1995; Simmons, 1995; Zemo,

1995). Often, TPH measurements are used to predict benzene concentrations. In practice, TPH

measurements do not predict benzene concentrations well. Based on the results of the LUFT

historical case analysis, where groundwater was measured for both TPH and BTEX compounds

at the same time, Rice et al. (1995) found that only 60% of the variability in benzene

groundwater concentrations were predicted by TPH measurements.

4.4. Technical Feasibility

The current regulatory framework does not allow for alternative approaches if technical or

economic infeasibility is determined (Gustafson et al., 1995d). There is no mechanism to define

technical and economic feasibility because groundwater is valued at a very high level through the

interpretations of Resolutions 88-63, 68-16, and 92-49. During the oversight of LUFT cleanup

actions, the Water Code requirements for economic considerations are commonly disregarded

(Stephenson, 1995).

4.4.1. Passive Bioremediation

• If a FHC source is removed, passive bioremediation processes act to naturally reduce

FHC plume mass and to eventually complete the FHC cleanup.

• Benzene plume lengths tend to stabilize at relatively short distances from the FHC release

site.

Subsurface microorganisms have been using petroleum hydrocarbons as a food source long

before man began using them as an energy source. While the specific mechanisms by which

FHCs are metabolized and degraded are not completely understood, knowledge of this

phenomenon, gained from empirical studies, can nevertheless be incorporated into the

management of site investigations and remediation.

The lack of widespread impact of LUFT plumes is because FHC plumes are often limited in

extent. Based on groundwater flow velocity, and soil and FHC properties, we can now estimate

the extent of FHC plumes. We now know that when plume lengths are measured in the field,

plume length stability is often reached at a distance from the source shorter than would be

expected without considering natural biodegradation. Groundwater scientists now recognize that

a major factor responsible for the shorter stable plume lengths is the aerobic and anaerobic

metabolism of indigenous soil microorganisms that digest FHCs and remove FHC mass from the

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

plume (Scow, 1982; Barker et al., 1987; Rifai et al., 1988; Chiang et al., 1989; Cozzarelli et al.,

1990; Baedecker et al., 1992, 1993; Bennett et al., 1993; Daniel, 1993; Eganhouse et al., 1993;

Salanitro, 1993; Cozzarelli et al., 1994; NRC, 1994; Borden et al., 1995; McNab and

Narasimhan, 1995).

As groundwater flows through an area where FHCs are present in the soils, FHCs dissolve

into the groundwater and are transported downgradient. Natural ubiquitous microbial populations

in the soil are stimulated and begin degrading the FHC to organic acid intermediates, and,

finally, to carbon dioxide and water. The microbes preferentially use oxygen as an electron

acceptor, but switch to other electron acceptors, such as NO

–1

, Fe

, Mn

, and SO

–2

(Cozzarelli and Baedecker, 1992; Salanitro et al., 1993). This process results in a large core area

of the plume in which oxygen, pH, and oxidation-reduction potential measurements are low,

whereas inorganic ion measurements of NO

–1

, Fe

, Mn

, and SO

–2

may be elevated relative

to a measurement location upgradient to the FHC release. Around the margins of the plume is a

transition zone in which oxygen becomes increasingly more available and aerobic microbial

degradation of FHCs proceeds. The anaerobic core of the plume is much larger in area than the

aerobic plume margins. Typically, biodegradation of FHCs proceeds most rapidly under aerobic

conditions, whereas the bulk of the FHC mass is degraded more slowly within the larger

anaerobic core.

The ability of microorganisms to degrade FHCs will be limited by the availability of electron

acceptors (Bouwer and McCarty, 1984; Vogel et al., 1987), but Air Force studies indicate that

the availability of electron acceptors may not be limiting and there is usually an excess capacity

for microbial FHC biodegradation (Wilson et al., 1994). Because of this excess capacity, passive

bioremediation may be expected to stabilize an FHC plume’s length and mass, in spite of the

presence of an active source that may be continually dissolving new FHC mass into the plume.

If the FHC source is removed to the point of residual saturation, these passive bioremediation

processes act to naturally reduce FHC plume mass and eventually complete the FHC cleanup. A

FHC will spread primarily due to the influence of gravity until the point is reached at which the

fluid no longer holds together as a single continuous phase, but rather lies in isolated residual

globules, i.e., in the so-called condition of residual saturation. At that point, the FHC has become

largely immobile under the usual subsurface pressure conditions and can migrate further only: 1)

in water according to its solubility; or 2) in the gas phase of the unsaturated zone (Schwille,

1988).

In a recent review of 200 LUFT cases in Napa County, 57 cases had groundwater impacts by

FHCs. An analysis of FHC plume lengths in 51 of these cases, indicated that plume total

petroleum hydrocarbon-gasoline (TPHg) concentrations greater than 50 ppb, the detection limit

for TPHg, did not extend beyond 200 ft in 90% of the cases (R. Lee, written communication to

S. Ritchie, 1995). Once contaminant sources were removed and the plume was stabilized, FHCs

in groundwater appeared to degrade naturally, in some cases at a rate of 50%–60% per year.

The detailed analysis of 271 LUFT cases by the SWRCB (Rice et al., 1995) as part of an

evaluation of more than 1,500 LUFT cases reported between 1985 and 1995 from 13 counties,

indicated that, in general, plume lengths change slowly and tend to stabilize at relatively short

distances from the FHC release site. Using 10 ppb as a practical limit of quantitation for plume

length estimates, this study found that plume concentrations greater than 10 ppb benzene

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

extended no more than about 250 feet in 90% of the cases. This finding supports the results of

the Napa County study.

4.4.2. Actively Engineered Remediation—Pump and Treat

• Pump and treat remediation alternatives are recognized as being ineffectual at reaching

MCL groundwater cleanup standards for FHCs within many geologic settings.

• Passive bioremediation can provide a remediation alternative that is as efficient as

actively engineered remediation process such as pump and treat.

During LUFT site remediation, FHC-contaminated groundwater is typically captured using

groundwater extraction wells and then treated aboveground to remove the FHCs. Often, the

treated groundwater is disposed of by releasing it to surface drainage or sanitary sewers, wasting

the resource. This remediation alternative is referred to as pump and treat. Even though

contaminated groundwater can be removed, the FHCs sorbed to the soil particulates tend to

remain (Freeze and Cherry, 1979; Isherwood et al., 1993; Cole, 1994). Hundreds of volumes of

water may be required to flush the FHC off the contaminated solid particulates (Bear et al.,

1994). This flushing can be very slow and expensive and may take several tens of years to reach

MCLs.

The LUFT historical case data analysis (Rice et al., 1995) indicates that plume lengths

decrease much more slowly than plume masses. This may occur because the FHCs sorbed onto

the soil particulates tend to inhibit changes in plume length. Even if groundwater FHC

concentrations become low, the soils desorb FHCs slowly back into groundwater (Karickhoff

et al., 1979) and a measurable plume length may persist. The length of the lingering plume is

defined by the extent of the soils with residual sorbed FHCs. This difficulty with removing the

FHC mass sorbed onto the soil particulates is one of the primary reasons that pump and treat

remediation alternatives are recognized as rarely effective at reaching MCL cleanup goals in

many hydrogeologic settings (Ross, 1993; MacDonald and Kavanaugh, 1994; NRC, 1994; U.S.

EPA, 1994).

In the exceptional cases where the FHC source was quickly controlled and removed, and a

relatively small dissolved FHC plume has not diffused deeply into the solid materials in a

shallow aquifer, pump and treat has achieved risk-based cleanup goals (MacDonald and

Kavanaugh, 1994; NRC, 1994). However, the success of pump and treat at these sites is largely

due to the action of passive bioremediation.

Although active remediation may help reduce dissolved plume mass, significant mass

reduction can occur with time, even without active remediation (Rice et al., 1995). In about 50%

of the cases where no actively engineered remediation was reported, plume average groundwater

benzene concentrations still decreased. In cases where pump and treat was reportedly used in

conjunction with over excavation, the likelihood of decreasing plume average benzene

concentrations with time improved by about 30% over instances where no active remediation

was reportedly performed (Rice et al., 1995).

The LUFT historical case analysis (Rice et al., 1995), the Napa County LUFT plume study

(R. Lee, written communication, to S. Ritchie, 1995), and other historical case studies (Hinchee

et al., 1986; Buscheck et al., 1993; McAllister and Chiang, 1994) found that once a FHC source

is removed, the time for passive bioremediation to reduce dissolved FHC plume mass by a factor

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

of 10 is about 1 to 3 years. Thus, passive bioremediation can provide a remediation alternative

that is as efficient as actively engineered remediation.

4.5. Economic Impact of Current LUFT Problem

4.5.1. Lack of Financial Incentives

• The current LUFT decision-making process does not result in cost-effective site closures,

in part, because financial incentives to support this result do not exist for cases in the

UST Cleanup Fund.

Based on anecdotal interviews with regulatory case workers, it is easier to keep a case open

and receive funds from the UST Cleanup Fund than to make a decision to close the case

(Dembroff, 1995). Furthermore, a perception that the UST Fund is a “golden goose” does not

encourage RPs or their consultants or contractors to actively pursue site closure.

To recover a perceived property value loss of a few tens of thousands of dollars, an RP can

spend a million dollars from the UST Cleanup Fund for cleanup at a site with groundwater that

poses a minimal risk or has limited beneficial use. Cleanup performance criteria are not linked to

UST Cleanup funding.

4.5.2. UST Cleanup Costs

• The average LUFT case reimbursement from the UST Cleanup Fund is currently about

$150,000.

• The ongoing and future fiscal effect of LUFT cleanups on the California economy is

estimated to be over $3 billion.

• Only about $1.5 billion will be raised by the time the UST Cleanup Fund program ends in

2005.

Federal regulations and state law declare that by 1998, all operating USTs must be upgraded

or replaced to meet new standards to reduce the likelihood of future contamination of

groundwater resources. The initial rate of tank removal and replacement was slow, but as

removals and upgrades continue, remediation cases will also increase, causing a climbing debt to

RPs and to the state. Less than 60% of the operating USTs have been upgraded or replaced.

The Barry Keene Underground Storage Tank Cleanup Trust Fund Act of 1989 established the

California Underground Storage Tank Cleanup Fund. An aggregate storage fee of six-tenths of a

cent (i.e., six mills) for each gallon of petroleum placed in a UST is required to be deposited in

the fund to pay for LUFT cleanups. Owners and operators of petroleum USTs are responsible for

the first $5,000 to $10,000 of cleanup per site. Residential tank owners do not have a deductible.

Cleanup costs above this are reimbursed from the fund up to $1 million. Any costs beyond this

become the responsibility of the site owner.

To date, over 10,000 applications have been received by the UST Cleanup Fund for

reimbursement. According to the UST Cleanup Fund, the average cost of each LUFT case

cleanup is about $150,000. Applying this information to the approximately 20,000 currently open

LUFT cases, the estimated cost to the California public is about $3 billion. If the approximately

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

7,000 previously closed sites are also included in this estimated cost, the overall fiscal effect of

LUFT cleanups on the California economy can be estimated to be about $4 billion. There is some

uncertainty in these numbers, because the average cost does not include costs over $1 million,

the limit of fund reimbursement, and many applicants estimate the full amount of $1 million,

even though they have not started cleanup efforts. Further, as the UST upgrade and replacement

process continues, additional leak sites will be discovered, making these cost estimates

conservative.

SB 1764, instituted in 1994, called for a fee increase to seven mills as of November 1, 1995,

with further increases to nine mills on January 1, 1996, and 12 mills as of January 1, 1997. The

fee increase is expected by legislative analysts to generate an additional $697 million between

1995 and 2005 when the storage fee ends. The projected income to the fund, generated from

sales of petroleum, will be about $1.5 billion. Therefore, given the estimated cost to the

California public of about $3 billion, there is a projected shortfall in funding of about

$1.5 billion.

4.5.3. The Value of Groundwater

• The current policies and regulations value groundwater too highly.

The average cost of a LUFT groundwater cleanup has been estimated to be $450,000 (C.

Stanley, personal communication). If this cost estimate is applied to the 0.7 acre-foot estimated

average volume of 1 ppb benzene plumes (Rice, et al., 1995), the value of the affected

groundwater can be estimated to be $637,000 per acre-foot. In comparison, the current cost of

developing a new water supply in California is estimated to be $700 to $900 per acre-foot. These

are important economic factors, which, by state law, must be taken into account when developing

cleanup requirements and policies.

4.6. Applicability of Risk-Based Corrective Action (RBCA) to

LUFT Decision Making

Existing language within the Water Code has appropriate guidance to make needed changes

to the LUFT cleanup decision-making process. The requirement to consider reasonable risk and

economic and technical feasibilities already exists within the current regulatory structure. An

RBCA decision-making approach meets the following requirements:

4.6.1. Systematized Site Evaluation and Selection of Cleanup

Requirements

• A RBCA approach to LUFT cleanups will provide guidance to reasonably manage risks

to ecosystems, and groundwater beneficial uses, as well as human health, while

considering technical and economic feasibility.

A RBCA approach to LUFT cleanups will provide guidance to reasonably manage risks to

ecosystems, and groundwater beneficial uses, as well as human health, while considering

technical and economic feasibility (Feldman, 1995; Gustafson et al., 1995e; Sickenger, 1995).

The basic dividing point for an FHC remediation policy is whether its driver is to be MCLs or a

risk-based consideration of FHC sources, exposure pathways, and receptors (Russell, 1995).

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

The existing LUFT decision-making framework is based on the problem of waste being

where it is not supposed to be. In this approach, the assumption is that all sites must be returned

to original cleanliness. The offsetting determinations of technical feasibility versus cost or

consideration of health or ecological damage from the process of remediation itself are usually

not considered.

An alternative decision-making process based on risk is a different framework than the one

currently in use. Risk inherently lies along a continuum. A focus on risk places the emphasis on

decisions that balance cost, value of the resource, and risk to human health and the environment.

The goal of a risk-based cleanup is to implement a risk-management strategy that takes the focus

of cleanup away from broadly defined numeric goals that have historically been technologically

infeasible and focuses on a more site-specific elimination or reduction of risk.

4.6.2. Broad, Systematic Decision-Making Approach That Can Be Adopted

at the State Level, but Permits Local Implementation

• A statewide, consistently applied RBCA decision-making framework will allow

regulators and RPs to know where they are in the decision-making process and what steps

to take next.

A statewide, consistently applied RBCA decision-making framework will allow regulators

and RPs to know where they are in the decision-making process and what steps to take next. The

RBCA framework also provides a means to systematize site evaluation, select remedial

alternatives (Graves, 1995c; Job, 1995; Moran, 1995b).

A RBCA approach can be tiered (Yim, 1995). Lower tiers base decisions on conservative

assumptions and typically require historical or screening level data to make decisions, thus

limiting characterization expense. Tier-one evaluations rely on a generic approach and apply to a

majority of LUFT cases and sites. Non- or minimally intrusive sampling is used to gather data,

and can rely on site classes developed using historical LUFT data. Higher tier evaluations would

be more costly, less conservative, and more representative of the site. Intrusive samplings are

more frequently performed during tier-two evaluations and more site-specific information is

considered during risk assessments .

4.6.3. Decision-Making Approach That is Technically Defensible and Strongly

Supported

• The recently developed ASTM RBCA framework offers a promising tiered decision-

making approach to LUFT cleanups.

The state can leverage the work of other national efforts to develop an RBCA LUFT

decision-making approach. The recently developed ASTM RBCA framework offers a promising

tiered decision-making approach to LUFT cleanups. The ASTM RBCA has received extensive

review by many national experts and is technically defensible and strongly supported by the U.S.

EPA. In addition, other ASTM standard sampling procedures can also be used, such as those

developed in ASTM Committee D18.21.02, Groundwater and Vadose Zone Investigations.

Further, there is a joint ASTM/U.S. EPA training program available for RBCA. The ASTM

RBCA tiers can be adapted to California’s needs by applying historical LUFT case data to tier-

one evaluation procedures.

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

4.6.4. Continuous Access and Utilization of Data for Decision Making

• The creation of a more credible LUFT site information system will expedite site closures.

A key to a LUFT RBCA decision-making approach is the continuous access and utilization

of data for decision making. Improved data acquisition and information management

infrastructure can make this data available and support the decision-making process. An RBCA

approach will facilitate the creation of a more credible LUFT site information system to expedite

site closures and improve the perception that FHCs are an adequately managed risk. The ASTM

RBCA has a well-developed reporting structure and form that would facilitate an approach that

relies on continuous data access for decision making.

5. Conclusions

5.1. Fuel Hydrocarbons (FHCs) Have Limited Impacts on

Human Health or the Environment

In California, benzene rarely impacts water-supply wells. This is because FHC plumes

typically are stable at relatively short distances from the source and LUFT releases usually occur

in urban and suburban settings with shallow groundwater. These shallow groundwaters are often

not recommended for use, as a matter of public policy, because they are susceptible to

degradation from a variety of sources besides FHCs, e.g., sanitary sewers, storm drains, and

septic tank leach fields as well as FHCs. In these settings, ecological risk and human drinking

water exposure pathways are effectively protected using California Well Standards.

If LUFT FHC plumes do not impact drinking water wells and other potential FHC exposure

pathways are evaluated and found to be safe, then a large proportion of existing LUFT cases

potentially pose an insignificant risk to human health and the environment. Once sources have

been removed, low-risk LUFT cases can often be safely closed while FHCs are allowed to

cleanup through passive bioremediation.

5.2. The Cost of Cleaning Up Leaking Underground Fuel Tank

(LUFT) Fuel Hydrocarbons (FHCs) is Often Inappropriate When

Compared to the Magnitude of the Impact on California’s

Groundwater Resources

The costs and level of effort expended on LUFT cases is disproportionally high relative to the

potential for adverse impacts on human health or the environment. Considerable amounts of

money and groundwater resources have been spent cleaning up LUFT FHCs that have affected a

very small proportion (0.0005%) of California total groundwater resource. The remediation of

LUFT FHCs in groundwater can cost more than $1 million per acre-foot. This cost is high

considering the small proportion of groundwater affected.

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

5.3. LUFT Groundwater Cleanup Requirements Are Derived

from Policies That Are Inconsistent with the Current State of

Knowledge and Experience

Knowledge and experience indicates that the assumptions that have guided LUFT

groundwater cleanup must be reevaluated. Since 1985, when the original LUFT Field Manual

was prepared, understanding of subsurface processes and the impacts of LUFT FHCs released

into the subsurface environment has increased significantly. Existing LUFT cleanup procedures

do not take into account the ability of soil or groundwater microorganisms to biotically and

abiotically reduce hydrocarbon contamination.

This new understanding of dissolved FHCs degradation can change the way that FHCs are

regulated. RWQCBs often choose not to regulate many shallow groundwater contaminants, e.g.,

nitrates or E. Coli from exfiltrating sanitary sewers or septic tank leach fields, because

knowledge and experience has shown that these contaminants typically remain relatively close to

release sites, rapidly degrade, and well construction and siting standards protect exposure

pathways. Similar knowledge and experience can be applied to FHCs, and regulatory agencies

can choose not to regulate FHCs at low risk LUFT sites.

The State Water Resources Control Board (SWRCB) policies that set groundwater cleanup

requirements to MCLs or background are a barrier to setting risk-based groundwater cleanup

goals and closing LUFT cases based on an evaluation of risk to human health and the

environment. The California Water Code is the law from which all other guidelines, resolutions,

policies, and procedures draw authority. The California Water Code provides adequate guidance

to permit flexibility in groundwater resource management and risk-based determinations of

groundwater cleanup levels for FHC releases.

Because a risk-based decision-making framework is not meaningful under the existing LUFT

regulatory framework, time and cost are not being adequately factored into the evaluation of

appropriate remedial strategies and the protection of beneficial uses of state waters. As a result,

society’s time and money are being misallocated to technically infeasible groundwater

remediation strategies, cleaning up groundwater that may not have a foreseeable economic

beneficial use.

5.4. Current Understanding of Passive Bioremediation

Processes in the Subsurface Environment Is Not Reflected in

the Present LUFT Cleanup Process

Given current understanding of FHC fate and transport in the subsurface environment,

passive bioremediation of soils and groundwater at LUFT sites can now be considered as an

appropriate remedial option. At sites where passive bioremediation is used, cleanup requirements

are not compromised or deferred, and the beneficial use of the groundwater is restored in

approximately the same time period as can be expected using actively engineered cleanups.

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

5.5. There Are Few Situations Where Pump and Treat Should

Be Attempted

The National Research Council (NRC) Committee on Groundwater Cleanup Alternatives

concludes that conventional pump and treat systems will be able to restore contaminated

groundwater to drinking water standards at only a limited number of sites (NRC, 1994). There

are few situations where pump and treat remediation should be attempted. At the core of a

revised LUFT decision-making approach is the need to recognize that in many cases, it is

technologically and economically infeasible to reach MCLs of 1.0 ppb for benzene using pump

and treat or other actively engineered groundwater remediation alternatives.

5.6. A Risk-Based Corrective Action (RBCA) Framework Offers

a Common Decision-Making Process To Systematically Address

LUFT Cleanup

No systematic, statewide decision-making framework exists for LUFT cases. In some cases,

regulatory oversight agencies have developed their own criteria for LUFT case characterization

and closure.

An RBCA decision-making framework can do a better job of implementing Water Code

requirements than existing processes. The American Society of Testing and Materials (ASTM)

RBCA framework meets the revised LUFT cleanup process requirements for a systematic,

consistent decision-making approach that can be adopted at a state level, but permits local

implementation.

The ASTM RBCA provides a basis to guide collection of data to support a systematic

decision-making approach. ASTM RBCA identifies risk-based target compounds that need to be

measured and continuously uses data to support the decision-making process. The ASTM RBCA

framework also provides means to define technical or economic feasibility, and a basis to

consider economic impacts during decision making by case managers. Further, the ASTM

RBCA allows for alternative approaches if technical or economic infeasibility is reported.

5.7. Modifications Would Be Necessary for the ASTM RBCA

Framework To Be Used in California

A modified ASTM RBCA tiered, decision-making approach will allow the formulation of

streamlined closure criteria that can encompass a majority of California's LUFT cases. This

modified ASTM RBCA approach can incorporate the results of the SWRCB's historical LUFT

case analysis to reflect California’s site-specific exposure parameters, as well as evaluate the

uncertainty associated with the assumptions used during risk evaluations.

Using a modified ASTM RBCA tier one decision-making process, cases would be evaluated

on the basis of exposure pathways, e.g., proximity of drinking water well and depth to

groundwater. This evaluation would include the consideration of existing risk management

programs such as well construction and siting standards. By immediately implementing a

modified ASTM RBCA framework, a large number of cases with minimal risk will be positioned

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

for immediate closure if policies are revised to allow risk-based groundwater cleanup

requirements.

Because a majority of LUFT cases occur in urban and suburban settings with depth to

groundwater less than 20 ft, a conservative assumption that groundwater is impacted can be

made in may cases. Source removal to residual saturation in conjunction with UST upgrade or

removal would be required.

In these shallow settings, source removal can usually be accomplished by excavation. Sites

with deeper groundwater would use the modified ASTM RBCA framework tier-one

methodology to evaluate the threat to groundwater and establish soils cleanup requirements.

Once the FHC source is removed, a monitoring program and plume management program

would be established while plumes are remediated using passive bioremediation. Plume

management strategies would be based on a modified ASTM RBCA framework and the

demonstration of plume stability.

At the heart of the ASTM RBCA framework is the idea of flexibility and continuous use of

current information. Continuous access to the data can increase hydrogeologic

representativeness. Use of local, regional, and state historical data minimizes “reinventing of the

wheel at each site” and permits the transfer of knowledge from one site to the next, reducing the

expense of site characterization. Site class specific target action screening levels can be

established using historical information.

The continuous utilization of LUFT data in the decision-making process facilitates an

“evergreen” approach. For example, LUFT action levels can periodically be reevaluated as

knowledge of an area increases and water/ land use or toxicity factors change.

5.8. A Common, Systematic Decision-Making Process Using

Standard Procedures Will Reduce Inconsistencies in Soils

Cleanup Requirements

RBCA can provide a systematic process to develop site-specific soil numeric standards for

LUFT cases. In addition, ASTM standard investigating techniques will ensure consistent data

collection.

There are no policy barriers to applying a RBCA decision-making framework to soils

contaminated by FHCs that do not pose a threat to groundwater. While the LUFT Historical Case

Analysis conducted by the SWRCB provided important information regarding the behavior of

FHC groundwater plumes, further study of LUFT soils-only cases is needed to assist in the

development of soils cleanup criteria to be used by a modified ASTM RBCA approach.

5.9. Total Petroleum Hydrocarbons (TPH) Measurements

Should Not Be Used to Predict Benzene Concentrations

Compounds such, as benzene, that are the primary components of a risk evaluation should be

measured directly, whenever possible, and not estimated from other indicator compounds.

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

6. Recommendations

6.1. Utilize passive bioremediation as a remediation alternative

whenever possible

• Minimize actively engineered LUFT remediation processes.

• Once passive bioremediation is demonstrated and unless there is a compelling reason

otherwise, close cases after source removal to the point of residual FHC saturation.

• In general, do not use the UST Cleanup Fund to implement pump and treat

remediation unless its effectiveness can be demonstrated.

• Support passive bioremediation with a monitoring program.

6.2. Immediately modify the ASTM RBCA framework based on

California historical LUFT case data

• Perform LUFT historical case studies on soils-only cases to support development

RBCA tier-one decision-making process.

• Use LUFT historical case data to modify ASTM RBCA to reflect California’s site-

specific exposure pathways

• Use LUFT historical case data to quantify the uncertainty in the assumptions that are

used during risk evaluations.

• Modify the ASTM RBCA tier-one decision-making process to encompass a majority

of California’s LUFT cases and facilitate and encourage the utilization of passive

bioremediation.

6.3. Apply a modified ASTM RBCA framework as soon as

possible to LUFT cases where FHCs have affected soil but do

not threaten groundwater

• There are no existing barriers to implementing ASTM RBCA at LUFT sites where

FHCs have only affected soils.

• Perform LUFT historical case studies on soils-only cases to support RBCA tier-one

development.

6.4. Modify the LUFT regulatory framework to allow the

consideration of risk-based cleanup goals higher than MCLs

• Modify SWRCB policies to remove barriers to applying a modified ASTM RBCA

framework to FHCs affecting groundwater.

• Once SWRCB policy barriers have been removed, apply modified ASTM RBCA

process to LUFT cases where FHCs have affected groundwater.

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

6.5. Identify a series of LUFT demonstration sites and form a

pilot LUFT closure committee

• LUFT demonstration sites should be chosen to:

— Act as training grounds for the implementation of a modified ASTM RBCA

process.

— Facilitate the implementation of a revised LUFT decision-making process.

— Test recommended sampling and monitoring procedures and technologies to

support passive bioremediation.

— Confirm cost effectiveness of the ASTM RBCA process.

• A pilot LUFT closure committee, made up of scientific professionals from

universities, private industry, and state agencies, should be set up to make

professional interpretations and recommendations regarding LUFT evaluations and

closures at the demonstration sites.

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

References

Baedecker, M.J., L.M. Cozzarelli, J.R. Evans, and P.P. Hearn (1992), “Authigenic Mineral

Formation in Aquifers Rich in Organic Material,” in Water–Rock Interaction, Y.K. Kharaka

and A.S. Maest (Eds.), A.A. Balkema, Rotterdam, Netherlands.

Baedecker, M.J., I.M. Cozzarelli, R.P. Eganhouse, D.I. Siegel, and P.C. Bennett (1993), “Crude

Oil in a Shallow Sand and Gravel Aquifer—III, Biogeochemical Reactions and Mass Balance

Modeling in Anoxic Groundwater,” Appl. Geochemistry 8, 569.

Barker, J.F., G.C. Patrick, and D. Major (1987), “Natural Attenuation of Aromatic Hydrocarbons

in a Shallow Sand Aquifer,” Groundwater Monitoring Review 7, 64.

Bear, J., E. Nichols, J. Ziagos, and A. Kulshrestha (1994), Effect of Contaminant Diffusion into

and out of Low-Permeability Zones, Lawrence Livermore National Laboratory, Livermore,

California (UCRL-ID-115626).

Bennett, P.C., D.E. Siegel, M.J. Baedecker, and M.F. Hult (1993), “Crude Oil in a Shallow Sand

and Gravel Aquifer, 1, Hydrogeology and Inorganic Geochemistry,” Appl. Geochem. 8, 529.

Borden, R.C., C.A. Gomez, and M.T. Becker (1995), “Geochemical Indicators of Intrinsic

Bioremediation,” J. Groundwater 33(2), 180.

Bouwer, E.J., and P.L. McCarty (1984), “Modeling of Trace Organics Biotransformation in the

Subsurface,” Groundwater 22, 433.

Buscheck, T.E., K.T. O’Reilly, and S.N. Nelson (1993), “Evaluation of Intrinsic Bioremediation

at Field Sites,” Proc. Conf. Petroleum Hydrocarbons and Organic Chemicals in

Groundwater, November 10–12, Houston, Texas.

California Department of Water Resources (CDWR) (1991), California Well Standards: Water

Wells, Monitoring Wells, Cathodic Protection Wells, Bulletin 74-90 (Supplement to Bulletin

74-81) (June).

California Regional Water Quality Control Board (CRWQCB) (1993), Compilation of Water

Quality Goals, Central Valley Region, State of California (May).

California Regional Water Quality Control Board (CRWQCB) (1994), Site Assessment and

Cleanup Guidebook, Vol. III: Self-Directed Process, Los Angeles Region, State of

California (May).

California Regional Water Quality Control Board (CRWQCB) (1995a), Interim Site Assessment

and Cleanup Guidebook, Vol. I: Assessment and Cleanup Guidance, Los Angeles Region,

State of California (February).

California Regional Water Quality Control Board (CRWQCB) (1995b), Interim Site Assessment

and Cleanup Guidebook, Vol. II: Appendixes A, B and C, Los Angeles Region, State of

California (February).

Chiang, C.Y., J.P. Salanitro, E.Y. Chai, J.D. Colthart, and C.L. Klein (November–December

1989), “Aerobic Biodegradation of Benzene, Toluene, and Xylene in a Sandy Aquifer—Data

Analysis and Computer Modeling,” J. Groundwater 27(6), 823.

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

*Clementsen, K.L. (1995), White Paper on the Underground Storage Tank (UST) Regulatory

Process, California Regional Water Quality Control Board, Central Valley Region, White

Paper, California State Senate Bill 1764 (June 13).

Cole, G.M. (1994), Assessment and Remediation of Petroleum Contaminated Sites, Lewis

Publishers, CRC Press, Boca Raton, Florida.

Cozzarelli, I.M., and M.J. Baedecker (1992), “Oxidation of Hydrocarbons Coupled to Reduction

of Inorganic Species in Groundwater,” Water–Rock Interaction, Vol. 1: Low Temperature

Environments, Y.K. Kharaka and A.S. Maest (Eds.), A.A. Balkema, Brookfield,

Massachusetts.

Cozzarelli, I.M., R.P. Eganhouse, and M.J. Baedecker (1990), “Transformation of Monoaromatic

Hydrocarbons to Organic Acids in Anoxic Groundwater Environment,” Environmental

Geology and Water Science 16, 135.

Cozzarelli, I.M., M.J. Baedecker, R.P. Eganhouse, and D.F. Goerlitz (1994), “The Geochemical

Evolution of Low-Molecular-Weight Organic Acids Derived from the Degradation of

Petroleum Contaminants in Groundwater,” Geochim. Cosmochim. Acta 58, 863.

*Crowley, J. (1995), Leaking Underground Storage Tank Oversight Program (LUSTOP)

Decision Process Summary. Santa Clara Valley Water District, White Paper, California State

Senate Bill 1764.

Daniel, D.E. (1993), Geotechnical Practice for Waste Disposal, Chapman and Hall, New York,

New York, 651.

*Dembroff, G.R. (1995), The Basic Framework of California’s UST Program Is Flawed,

Ultramar, Inc., Hanford, California, White Paper, California State Senate Bill 1764 (June 8).

*Earnest, K.R. (1995), The Cleanup Standards Are Arbitrary and Capricious and Do Not Reflect

the True Threat to Human Health and the Environment, Ultramar, Inc., Hanford, California,

White Paper, California State Senate Bill 1764 (June 13).

Eganhouse, R.P., M.J. Baedecker, I.M. Cozzarelli, G.R. Aiken, K.A. Thorn, and T.F. Dorsey

(1993), “Crude Oil in a Shallow Sand and Gravel Aquifer, 2, Organic Geochemistry,” Appl.

Geochem. 8, 551.

Feldman, L. (1995), “Risk-Based Environmental Remediation: Defining the Magnitude of

Potential Health and Environmental Threats,” California Environmental Law and Regulation

Reporter 5(5), 85.

*Fox, T.A. (1995), The `Non-Degradation Policy’ Is in Conflict with the Porter–Cologne Water

Quality Control Act (Water Code), Ultramar, Inc., Hanford, California, White Paper,

California State Senate Bill 1764 (June 13).

Freeze, R.A., and J.A. Cherry (1979), Groundwater, Prentice-Hall, Englewood Cliffs, New

Jersey.

*Graves, K.L. (1995a), Sources of Drinking Water, Advisory Committee, White Paper,

California State Senate Bill 1764 (June 13).

*Graves, K.L. (1995b), LUST Data Management, Advisory Committee, White Paper, California

State Senate Bill 1764 (June 12).

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

*Graves, K.L. (1995c), Let’s Implement ASTM Risk Based Corrective Action, Advisory

Committee, White Paper, California State Senate Bill 1764 (June 8).

*Gustafson, J.B., H.B. Boschetto, F.R. Fossati, E.W. Richter, D.T. Kirk, and C.M. Claudio

(1995a), Policies, Guidelines, and Methods Which Are Used To Establish Those

Standards (a), Shell Oil Company, White Paper, California State Senate Bill 1764 (June 14).

*Gustafson, J.B., H.B. Boschetto, F.R. Fossati, E.W. Richter, D.T. Kirk, and C.M. Claudio

(1995b), Groundwater Monitoring Requirements, Remediation Techniques, and

Methodologies (b), Shell Oil Company, White Paper, California State Senate Bill 1764 (June

14).

*Gustafson, J.B., H.B. Boschetto, F.R. Fossati, E.W. Richter, D.T. Kirk, and C.M. Claudio

(1995c), Cleanup Standards Which Responsible Parties Conducting Corrective Action

Pursuant to This Article Are Required To Meet, Shell Oil Company, White Paper, California

State Senate Bill 1764 (June 14).

*Gustafson, J.B., H.B. Boschetto, F.R. Fossati, E.W. Richter, D.T. Kirk, and C.M. Claudio

(1995d), Criteria for Determining That Remediation Has Been Satisfactorily Completed,

Shell Oil Company, White Paper, California State Senate Bill 1764 (June 14).

*Gustafson, J.B., H.B. Boschetto, F.R. Fossati, E.W. Richter, D.T. Kirk, and C.M. Claudio

(1995e), Groundwater Monitoring Requirements, Remediation Techniques, and

Methodologies, Shell Oil Company, White Paper, California State Senate Bill 1764 (June

14).

Hadley, P. (1995), written communication to J.G. Giannopoulos.

Hadley, P., and R. Armstrong (1991), “Where’s the Benzene?” Groundwater 29(1), 40.

Hinchee, R.E., J.T. Wilson, and D.C. Downey (Eds.) (1986), Intrinsic Bioremediation, Battelle

Press, Columbus, Ohio.

Isherwood, W.F., D. Rice, Jr., J. Ziagos, and E. Nichols (1993), “‘Smart’ Pump and Treat,”

J. Hazardous Materials 35, 413.

*Job, B. (1995), The Current Regime for LUFT Site Management Has Been Frequently

Criticized as Lacking in Consistency, Efficacy, and Cost Effectiveness, San Francisco Bay

Regional Water Quality Control Board, White Paper, California State Senate Bill 1764

(June).

Karickhoff, S.W., D.S. Brown, and T.A. Scott (1979), “Sorption of Hydrophobic Pollutants on

Natural Sediments,” Water Research 13, 241.

Lee, R. (1995), written communication to S. Ritchie.

MacDonald, J.A., and M.C. Kavanaugh (1994), “Restoring Contaminated Groundwater: An

Achievable Goal?” Environ. Sci. Technol. 28(8), 362A.

Marshack, J.B. (1993), written communication to J. Farr, California State Senate Bill 1764

Committee Chairman, “California’s Water Quality Standards and Their Applicability to Site

Assessment and Cleanup,” Central Valley Region Regional Water Quality Control Board,

State of California (May 19).

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

McAllister, P.M., and C.Y. Chiang (1994), “A Practical Approach To Evaluating Natural

Attenuation of Contaminants in Groundwater” Groundwater Monitoring and Remediation.

(Spring).

McNab, W.W., Jr., and T.N. Narasimhan (1995), “Reactive Transport of Petroleum Hydrocarbon

Constituents in a Shallow Aquifer: Modeling Geochemical Interactions Between Organic

and Inorganic Species” Water Resources Research 31(8), 2027.

*Moran, R.J. (1995a), Consistency, Reasonableness of Requirements, Arco Products Company,

Los Angeles, California, White Paper, California State Senate Bill 1764 (June 13).

*Moran, R.J. (1995b), Remediation Prioritization, Arco Products Company, Los Angeles,

California, White Paper, California State Senate Bill 1764 (June 13).

National Research Council (NRC) (1994), Alternatives for Groundwater Cleanup, National

Academy Press, Washington, D.C.

Rempel, R. (1995), Memorandum to J.G. Giannopoulos, “Review of Available Data from Sites

Reported in LUSTIS Database as Having Affected a Water Supply Well,” State Water

Resources Control Board, Division of Clean Water Programs (August 8).

Rice, D.W., R. Grose, J. Michaelsen, S. Clister, B. Dooher, D. MacQueen, S. Cullen,

W. Kastenberg, L. Everett, and M. Marino (1995), California Leaking Underground Fuel

Tank (LUFT) Historical Case Analyses, Lawrence Livermore National Laboratory,

Livermore, California (UCRL-AR-121762).

Rifai, H.S., P.B. Bedient, J.T. Wilson, K.M. Miller, and J.M. Armstrong (1988), “Biodegradation

Modeling at an Aviation Fuel Spill Site,” J. Environmental Engineering, ASCE 114, 1007.

Ross, D.L. (1993), “An Environmentalist’s Perspective on Alternatives to ‘Pump and Treat’ for

Groundwater Remediation,” Groundwater Monitoring Review, (Fall) 92.

Russell, M. (1995), Contamination or Risk: Cost Implications of Alternative Superfund

Configurations, Paper presented at the American Association for the Advancement of

Science Meeting, Atlanta, Georgia (February 19).

Salanitro, J.P. (1993), “The Role of Bioattenuation in the Management of Aromatic Hydrocarbon

Plumes in Aquifers,” Groundwater Monitoring and Remediation, (Fall) 150.

Salanitro, J.P., L.A. Diaz, M.P. Williams, and H.L. Wisniewski (1993), “Simple Method To

Estimate Aromatic Hydrocarbon Degrading Units (Microbes) in Soil and Groundwater,”

Presented at the 1993 Int. Symposium on Subsurface Microbiology (ISSM93), September

19–24, Bath, England.

Scow, K.M. (1982), Chapter 9, “Rate of Biodegration,” W.T. Lyman, W.F. Reehl, and D.H.

Rosenblatt (Eds.), Handbook of Chemical Property Estimation Methods. Environmental

Behavior of Compounds, McGraw-Hill Books Company, New York, New York.

Schwille, F. (1988), Dense Chlorinated Solvents in Porous and Fractured Media, Lewis

Publishers, Inc., Chelsea, Michigan.

*Sickenger, J., Western States Petroleum Association (1995), written communication to

J. Giannopoulos (August 2).

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

*Simmons, B.P. (1995), California Underground Storage Tank Program—Testing Issue: How

can the cost of UST testing be reduced while still providing data of acceptable quality?

Department of Toxic Substances Control, California Environmental Protection Agency,

White Paper, California State Senate Bill 1764 (June 13).

State Water Resources Control Board (SWRCB) (1989), Leaking Underground Fuel Tank Field

Manual: Guidelines for Site Assessment, Cleanup, and Underground Storage Tank Closure,

California Environmental Protection Agency (October).

State Water Resources Control Board (SWRCB) (1992a), Petroleum Underground Storage Tank

Cleanup Fund Corrective Action Guide, California Environmental Protection Agency (June).

State Water Resources Control Board (SWRCB) (1992b), Policies and Procedures for

Investigation and Cleanup and Abatement of Discharges under Water Code Section 13304,

California Environmental Protection Agency (June).

State Water Resources Control Board (SWRCB) (1993), California Underground Storage Tank

Regulations, California Environmental Protection Agency (March).

State Water Resources Control Board (SWRCB) (1994), California Underground Storage Tank

Regulations 1994, Title 23, Division 3, Chapter 16, “California Code of Regulations,” and

Chapter 6.7, “Health and Safety Code,” State of California.

State Water Resources Control Board (SWRCB) (1995), Leaking Underground Storage Tank

Information System (LUSTIS) Quarterly Report. State Water Resources Control Board,

Sacramento, California (July).

*Stephenson, R.K. (1995), Regulatory Requirements Related to Monitoring, Assessment, and

Remediation of UST Projects Are Very Often Subjective, Done Without Regard to Cost vs

Benefit, and Are Based on Local

Guidelines in Place of the Environmental Law, Ultramar,

Inc., Hanford, California, White Paper, California State Senate Bill 1764 (June 14).

Torres, G. (1993), “Report on Closed Leaking Underground Fuel Tank (LUFT) Case File

Reviews,” Internal memorandum from Gil Torres, Senior Engineering Geologist,

Underground Storage Tank Program, State Water Resources Control Board, to Harry M.

Schueller, Chief, Division of Clean Water Programs and Mike McDonald, Manager,

Underground Tank Program (September).

U.S. Environmental Protection Agency (1994), How To Evaluate Alternative Cleanup

Technologies for Underground Storage Tank Sites, Office of Solid Waste and Emergency

Response (EPA/510-B-94-003) (October).

Vogel, T.M., C.S. Criddle, and P.L. McCarty (1987), “Transformations of Halogenated Aliphatic

Compounds,” Environ. Sci. Technol. 21, 722.

Ward, K. (1995), written communication to J.G. Giannopoulos.

Wilson, J.T., F.M. Pfeffer, J.W. Weaver, D.H. Kampbell, R.S. Kerr, T.H. Wiedemeier, J.E.

Hansen, and R.N. Miller (1994), “Intrinsic Bioremediation of JP-4 Jet Fuel,” Proc.

Symposium on Intrinsic Bioremediation of Groundwater, Denver, Colorado (August 30–

September 1), 60.

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

*Yim, R.A. (1995), Purpose of Resource Protection Standards; Need for Tiered Decision

Making, Yim, Okun & Watson, Sacramento, California, White Paper, California State Senate

Bill 1764 (June 14).

*Zemo, D.A., T.E. Graf, J.W. Embree, J.E. Bruya†, and K.L. Graves‡ (1995), Recommended

Analytical Requirements for Soil and Groundwater Samples Affected by Petroleum

Hydrocarbons, Geomatrix Consultants, Inc., †Friedman and Bruya, Inc., ‡Regional Water

Quality Control Board (San Francisco Bay Region), White Paper, California State Senate Bill

1764 (June).

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

Acronyms

ASTM American Society for Testing and Materials

BTEX Benzene, toluene, ethylbenzene, xylene

DHS Department of Health Services

FHC Fuel hydrocarbon

LLNL Lawrence Livermore National Laboratory

LOP Local oversight program

LUFT Leaking underground fuel tank

MCL Maximum contaminant level

NRC National Research Council

ppb Part per billion

RBCA Risk-Based Corrective Action

RPs Responsible parties

SWRCB State Water Resources Control Board

TPH Total petroleum hydrocarbon

TPHg Total petroleum hydrocarbon-gasoline

UST Underground storage tank

UCRL-AR-121762 Recommendations To Improve LUFTs October 16, 1995

DISCLAIMER

This document was prepared as an account of work sponsored by an agency of the United States Government.

Neither the United States Government nor the University of California nor any of their employees, makes any

warranty, express of implied, or assumes any legal liability or responsibility for the accuracy, completeness, or

usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe

privately owned rights. Reference herein to any specific commercial products, process, or service by trade name,

trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation,

or favoring by the United States Government or the University of California. The views and opinions of authors

expressed herein do not necessarily state or reflect those of the United States Government or the University of

California, and shall not be used for advertising or product endorsement purposes.

Work performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under Contract W-

7405-Eng-48.

Site characterization in the USA and Europe - A comparative review of approaches, costs and solutions driven by objectives

Article

Jul 2002
Land Contam Reclamat

Site characterization methods are driven by objectives, which may appear at first glance to be strictly dictated by policies. However, as related to 'contaminated land' characterization, these objectives are clearly driven by science and technology. The science and technology underlying contaminated land characterization and remediation in the USA has evolved as a result of changing trends in regulatory and public objectives, as well as the need to allocate finite public and private resources in the most effective manner possible. This trend, including the mistakes made and lessons learned along the way, affords Europeans a unique opportunity to avoid the pitfalls experienced in the USA and to more efficiently apply best available technologies for sustainable contaminated land management. It also allows for the best use of the limited resource of truly secure landfill space for wastes which cannot be remediated by other, in situ methods, and eliminates remediation of sites which do not present a true hazard. This paper examines the evolution of contaminated land site characterization and remediation in the USA and compares the current state-of-the-art practices with those currently applied in Europe. The US and European regulatory drivers, costs and objectives of contaminated land site characterization are compared and opportunities are identified to capitalise on the lessons learned from the US experience.

Green Remediation or Sustainable Remediation: Moving From Dialogue to Common Practice

Article

Mar 2015
Remed J

Different points of view have emerged concerning how to best consider and address the largely unexamined ancillary environmental impacts, and more particularly the social and economic impacts, of remediation activities. These views are generally categorized as “green remediation” and “sustainable remediation.” This article dissects the commonalities and differences between “green” and “sustainable” remediation approaches. Several key obstacles to the broader implementation of sustainable remediation practices are identified. Similarities identified among the two concepts offer a common ground and areas of collaboration. The objective of this article is to support maturation of the remediation industry by addressing the opposition to and supporting the implementation of sustainable remediation practices, including offering recommendations for a path forward. ©2015 Wiley Periodicals, Inc.

Processes in Microbial Transport in the Natural Subsurface

Article

Aug 2002
ADV WATER RESOUR

This is a review of physical, chemical, and biological processes governing microbial transport in the saturated subsurface. We begin with the conceptual models of the biophase that underlie mathematical descriptions of these processes and the physical processes that provide the framework for recent focus on less understood processes. Novel conceptual models of the interactions between cell surface structures and other surfaces are introduced, that are more realistic than the oft-relied upon DLVO theory of colloid stability. Biological processes reviewed include active adhesion/detachment (cell partitioning between aqueous and solid phase initiated by cell metabolism) and chemotaxis (motility in response to chemical gradients). We also discuss mathematical-issues involved in upscaling results from the cell scale to the Darcy and field scales. Finally, recent studies at the Oyster, Virginia field site are discussed in terms of relating laboratory results to field scale problems of bioremediation and pathogen transport in the natural subsurface.

Biotechnologies for Remediation of Organic Pollution

Chapter

Jan 1997

R. C. Ragaini

It is well known that certain organic chemicals can accumulate in the environment, and threaten human health and environmental quality. Furthermore, indigenous microorganisms have been shown to have an enormous natural capacity to degrade certain organic compounds, both aerobically and anaerobically. Meanwhile, significant new research efforts are expanding the range of microorganisms used for bioremediation, including faster degradation kinetics, a wider range of degradable organic compounds, and a broader range of microbial conditions. This chapter reviews the biotechnologies used for the environmental restoration and waste management of organic pollution.

Soil Radionuclide Plumes

Article

Jan 2002

Natural Attenuation

Chapter

Nov 2011

Natural Attenuation (NA) has emerged during the last 10–15 years as a useful and cost-efficient alternative approach for contaminated site management. It refers to the naturally occurring processes like dispersion, diffusion, sorption, volatilization, degradation and transformation, all of which can substantially decrease contaminant concentration, mass, toxicity and/or mobility within soil and groundwater. The efficiency of Natural Attenuation processes depends to a large extent on site-specific conditions, primarily on the type of contaminants present at the site. Proving and evaluating the efficiency of Natural Attenuation processes is a prerequisite for accepting them as the sole or additional remediation alternative. The implementation of Natural Attenuation as a remediation alternative, i.e. the monitoring that assures sustainability of Natural Attenuation processes over time, is called Monitored Natural Attenuation (MNA). This chapter presents an overview of the history and political acceptance of Natural Attenuation and the principles on which it was built. Specifically, it describes how the different processes act on contaminant plume development and explores methods of evaluating Natural Attenuation processes and proving their effectiveness. A stepwise approach to assess and implement Natural Attenuation is presented, followed by three sections on the most frequently found contaminant groups for which Monitored Natural Attenuation is being applied. These are petroleum hydrocarbons, chlorinated hydrocarbons and tar oil contaminants. Characteristics of these contaminant groups, the resulting contaminant-specific potential for implementation of Natural Attenuation and the challenges to be expected, are elucidated and discussed.

Yardsticks to Integrate Risk Assessment, Risk Management, and Groundwater Remediation

Article

Jun 2015
Remed J

Remediation of contaminated sites has focused largely on restoration of groundwater aquifers. Often the stated remedial goal is to achieve conditions allowing unrestricted use and unrestricted exposure. Such total groundwater cleanup has occurred at some sites, but is the exception rather than the rule. At the same time, significant effort occurs to perform risk assessments for potential exposure to contaminants in groundwater at sites, both before and after remediation. The logical synergy between risk assessment and remediation is for risk management to seek opportunities for optimal use of groundwater based upon realistic expectations of cleanup technologies and the relevant acceptable residual (postremediation) levels of contaminants. This article explores an approach to improve this synergistic relationship between risk assessment, risk management, and remediation for groundwater cleanups.

A tiered approach to assess risk due to contaminant migration in groundwater

Technical Report

Full-text available

Jan 2007

The Illinois Underground Storage Tank Fund: Tanks for Nothing

Article

Oct 2013
Polit Pol

Meagan Musgrave

At the expense of those who use petroleum in I llinois, the U nderground S torage T ank ( UST ) F und provides tank owners and operators with the financial support they need to remediate leaking UST sites. Little has been written on the sociodemographic factors that influence UST site remediation because most analysts characterize “open” tank sites (those in need of remediation) using only descriptive statistics. I examine how socioeconomic variables and the passage of time influence the distribution of open sites within I llinois and find that only time contributes to the likelihood that a site will remain open. This result suggests that reducing the reimbursement timeline for tank owners and operators should be considered as an effective strategy for increasing remediation rates, both within I llinois and throughout the U nited S tates. Related Articles Neill , Katharine A. , and John C. Morris . 2012 . “.” Politics & Policy 40 (): 629 ‐ 656 . http://onlinelibrary.wiley.com/doi/10.1111/j.1747‐1346.2012.00371.x/abstract Pautz , Michelle C. 2009 . “.” Politics & Policy 37 (): 1047 ‐ 1072 . http://onlinelibrary.wiley.com/doi/10.1111/j.1747‐1346.2009.00210.x/abstract Shrock , Peter . 2010 . “.” Politics & Policy 38 (): 991 ‐ 1013 . http://onlinelibrary.wiley.com/doi/10.1111/j.1747‐1346.2010.00261.x/abstract Related Media DeHaan , Patrick . 2012 . “” CBS . August 7. http://chicago.cbslocal.com/2012/08/07/illinois‐gas‐prices‐now‐the‐highest‐in‐continental‐u‐s/ . 2008 . . May. http://www.epa.state.il.us/land/lust/ust‐fund.html

Remediation by Natural Attenuation?

Article

Aug 1999
GROUND WATER MONIT R

John Odermatt

There is renewed interest in the use of remediation by natural attenuation (RNA) during the last few years. As a result, a number of organizations have developed guidance on implementing risk-based corrective action and RNA. However, many state agencies do not allow natural attenuation as a standalone remedial option at contaminated sites primarily due to the ambiguous data obtained. Several factors have been identified to cause this problem. These factors include inappropriate well construction, transient dilution effects from a fluctuating groundwater table, and the inappropriate location of wells. In addition, there are some common data validation problems that have been associated with groundwater geochemical data reported to regulatory agencies.

Assessment and Remediation of Petroleum Contaminated Sites

Book

May 2018

G.Mattney Cole

Geotechnical Practice for Waste Disposal

Chapter

Jan 1993

David E. Daniel

Modeling of Trace Organics Biotransformation in the Subsurface

Article

Jul 1984
GROUND WATER

Biofilm processes are potentially important for transformations of organic micropollutants in ground water. Some theoretical hypotheses and empirical observations suggest that a concentration threshold exists for some compounds below which the concentration cannot be reduced by bacterial action. However, in the presence of one compound at a relatively high concentration, termed the primary substrate, another compound present at trace concentrations, termed the secondary substrate, can be biotransformed as well. These concepts were evaluated through laboratory column studies with several halogenated organic compounds of importance in ground water. A biofilm model can successfully describe utilization of trace substrates, and application to modeling the subsurface is discussed. A simplified batch model with first-order kinetics may be adequate for describing subsurface microbial processes when low active organism and pollutant concentrations exist over a large scale.

“Smart” pump and treat

Article

Dec 1993
J HAZARD MATER

Lawrence Livermore National Laboratory (LLNL) is approaching the final phase of the Superfund decision-making process for site restoration and will soon initiate full-scale clean-up. Despite some well-publicized perceived failings of the pump and treat approach, we have concluded that intelligent application of this strategy is the best choice for ground water restoration at LLNL. Our proposed approach differs sufficiently from the pump-and-treat methods implemented at other sites that we call it “smart” pump and treat. Smart pump and treat consists of four distinct, but interrelated, elements: three pre-remediation strategies and one applying to the active management of the extraction process. Together, these techniques constitute an integrated program that embodies crucial aspects of contaminant flow and transport to speed up the remediation of contaminated aquifers. The four elements are: (1) a spatially detailed site characterization, linked with regional hydrogeologic simulations; (2) directed extraction, where the extraction and recharge locations are controlled by field-determined hydrogeologic parameters; (3) field-validated simulations that match the complexity of the collected data; and (4) adaptive pumping and reinjection where spatial positions and rates vary with time. Together, these techniques minimize the cost and the time to reach regulatory-directed cleanup goals and maximize the rate of contaminant removal.

The Best Student Paper in Organic Geochemistry: The Geochemical evolution of low-molecular-weight organic acids derived from the degradation of petroleum contaminants in groundwater

Article

May 1996
GEOCHIM COSMOCHIM AC

Natural Attenuation of Aromatic Hydrocarbons in a Shallow Sand Aquifer

Article

Mar 1987
GROUND WATER MONIT R

Inadvertent release of petroleum products such as gasoline into the subsurface can initiate ground water contamination, particularly by the toxic, water‐soluble and mobile gasoline components: benzene, toluene and xylenes (BTX). This study was undertaken to examine the processes controlling the rate of movement and the persistence of dissolved BTX in ground water in a shallow, unconfined sand aquifer. Water containing about 7.6 mg/ L total BTX was introduced below the water table and the migration of contaminants through a sandy aquifer was monitored using a dense sampling network. BTX components migrated slightly slower than the ground water due to sorptive retardation. Essentially all the injected mass of BTX was lost within 434 days due to biodegradation. Rates of mass loss were similar for all monoaromatics; benzene was the only component to persist beyond 270 days. Laboratory biodegradation experiments produced similar rates, even when the initial BTX concentration varied. A dominant control over BTX biodegradation was the availability of dissolved oxygen. BTX persisted at the field site in layers low in dissolved oxygen. Decreasing mass loss rates over time observed in the field experiment are not likely due to first‐order deeradation rates, but rather to the persistence of small fractions of BTX mass in anoxic layers.

A Practical Approach to Evaluating Natural Attenuation of Contaminants in Ground Water

Article

May 1994

The extent of natural attenuation is an important consideration in determining the most appropriate corrective action at sites where ground water quality has been impacted by releases of petroleum hydrocarbons or other chemicals. The objective of this study was to develop a practical approach that would evaluate natural attenuation based on easily obtained field data and field tested indicators of natural attenuation. The primary indicators that can be used to evaluate natural attenuation include plume characteristics and dissolved oxygen levels in ground water. Case studies of actual field sites show that plumes migrate more slowly than expected, reach a steady state, and decrease in extent and concentration when natural attenuation is occurring. Background dissolved oxygen levels greater than 1 to 2 mg/L and in inverse correlation between dissolved oxygen and contaminant levels have been identified through laboratory and field studies as key indicators of aerobic biodegradation, an important attenuation mechanism. Secondary indicators such as geochemical data, and more intensive method such as contaminant mass balances, laboratory microcosm studies, and detailed ground water modeling can demonstrate natural attenuation as well.

Aerobic Biodegradation of Benzene, Toluene, and Xylene in a Sandy Aquifer-Data Analysis and Computer Modeling

Article

Nov 1989
GROUND WATER

Soluble hydrocarbon and dissolved oxygen (DO) in a shallow aquifer beneath a field site were characterized by sampling ground water at 42 monitoring wells. Results from 10 sampling periods over three years showed a significant reduction in total benzene mass with time in ground water. These reduction and leakage rates from sources were determined from material balance and nonlinear least-squares analyses. The natural attenuation rate was calculated to be 0.95%/day. Spatial relationships between DO and total benzene, toluene, and xylene (BTX) were shown to be strongly correlated by statistical analyses and solute transport modeling. In addition, laboratory microcosm biodegradation experiments were performed to determine possible threshold limits for aromatic hydrocarbon oxidation under varying levels of dissolved oxygen. The results were remarkably consistent with field data on the presence of high or low levels of BTX and DO in several monitoring well-water samples.

Reactive Transport of Petroleum Hydrocarbon Constituents in a Shallow Aquifer: Modeling Geochemical Interactions Between Organic and Inorganic Species

Article

Aug 1995

Dissolved organic contaminants such as petroleum hydrocarbon constituents are often observed to degrade in groundwater environments through biologically mediated transformation reactions into carbon dioxide, methane, or intermediate organic compounds. Such transformations are closely tied to local geochemical conditions. Favorable degradation pathways depend upon local redox conditions through thermodynamic constraints and the availability of appropriate mediating microbial populations. Conversely, the progress of the degradation reactions may affect the chemical composition of groundwater through changes in electron donor/acceptor speciation and pH, possibly inducing mineral precipitation/dissolution reactions. Transport of reactive organic and inorganic aqueous species through open systems may enhance the reaction process by mixing unlike waters and producing a state of general thermodynamic disequilibrium. In this study, field data from an aquifer contaminated by petroleum hydrocarbons have been analyzed using a mathematical model which dynamically couples equilibrium geochemistry of inorganic constituents, kinetically dominated sequential degradation of organic compounds, and advective-dispersive chemical transport. Simulation results indicate that coupled geochemical processes inferred from field data, such as organic biodegradation, iron reduction and dissolution, and methanogenesis, can be successfully modeled using a partial-redox-disequilibrium approach. The results of this study also suggest how the modeling approach can be used to study system sensitivity to various physical and chemical parameters, such as the effect of dispersion on the position of chemical fronts and the impact of alternative buffering mineral phases (e.g., goethite versus amorphous Fe(OH)3) on water chemistry.

Geochemical Indicators of Intrinsic Bioremediation

Article

Mar 1995
GROUND WATER

A detailed field investigation has been completed at a gasoline-contaminated aquifer near Rocky Point, NC, to examine possible indicators of intrinsic bioremediation and identify factors that may significantly influence the rae and extent of bioremediation. The dissolved plume of benzene, toluene, ethylbenzene, and xylene (BTEX) in ground water is naturally degrading. Toluene and o-xylene are most rapidly degraded followed by m-, p-xylene, and benzene. Ethylbenzene appears to degrade very slowly under anaerobic conditions present in the center of the plume. The rate and extent of biodegradation appears to be strongly influenced by the type and quantity of electron acceptors present in the aquifer. At the upgradient edge of the plume, nitrate, ferric iron, and oxygen are used as terminal electron acceptors during hydrocarbon biodegradation. The equivalent of 40 to 50 mg/l of hydrocarbon is degraded based on the increase in dissolved COâ relative to background ground water. Immediately downgradient of the source area, sulfate and iron are the dominant electron acceptors. Toluene and o-xylene are rapidly removed in this region. Once the available oxygen, nitrate, and sulfate are consumed, biodegradation is limited and appears to be controlled by mixing and aerobic biodegradation at the plume fringes.

Recommendations To Improve the Cleanup Process for California's Leaking Underground Fuel Tanks (LUFTs)

Abstract

Recommended publications

Use of alternative rules (other than the 1(2s)) for evaluating interlaboratory performance data

West Valley High-Level Waste Tank Lay-Up Strategies

Technical issues associated with in situ vitrification of the INEL Subsurface Disposal Area. Volume...

Closure of 324 Facility potential HEPA filter failure unreviewed safety questions