SFUND RECORDS CTR

2106081

&EPA

Sola Optical USA, Inc.

Superfund Site

; ENVIRONMENTAL PROTECTION AGENCY • REGION 9 • SAN FRANClSpO, CA • JANUARY 2007

EPA Proposes Amending the Clean-up Plan for

Contaminated Ground water

Proposed Plan at a Glance

The Problem

A groundwater extraction and treatment system began

operating at the Sola Optical USA, Inc. Superfund Site in

Petaluma, California in 1988. Expanded in 1992, the

system was expected to restore the shallow groundwater to

clean-up standards within 15-20 years, achieving that goal

between 2007 and 2012. However, after several years the

effectiveness of the extraction and treatment system

appeared to stall with respect to certain contaminants,

concentrations of which eventually stabilized at levels

above the clean-up standards. In response to the diminishing value of the system, the responsible party and the

United States Environmental Protection Agency (EPA)

began to consider alternative methods for restoring groundwater quality. In the meantime, due to natural degradation

processes the contamination levels dropped and clean-up

levels have now been achieved for all but one contaminant

which is still present in elevated concentrations at a single

well on the site.

The Solution

EPA proposes to formally adopt Monitored Natural Attenuation (MNA) as the method for completing groundwater

restoration. MNA is an approach that relies on natural

processes, such as biodegradation, to attain the clean-up

goals within a reasonable time frame. EPA also proposes

to restrict use of the contaminated groundwater until the

groundwater meets California's drinking water standard for

the remaining contaminant, 1,1-DCA.

Your Comments

The public is invited to participate in the remedy selection

process and to submit comments on the proposed amendment to the clean-up plan. Comments on this Proposed

Plan are welcome, both during our public meeting and by

writing to EPA (see back page for contact information).

EPA will consider your comments in making our final

clean-up decision, and written responses to any comments

will be included in the final decision document.

Community Meeting

Wednesday, January 24,2007

6:30 p.m. - 8:30 p.m.

Petaluma Public Library, Meeting Room

100 Fairgrounds Drive

Petaluma, California

Comment Period

January 20, 2007 through

February 20, 2007

The Sola Optical USA, Inc. (Sola) Superfund Site (Site) is

in Petaluma, California, at 1500 Cader Lane, just west of

the intersection of Lakeville Highway and Interstate 101.

From 1978 through 2001, Sola manufactured eyeglass

lenses at the Site. When operations first began, Sola stored

various solvents used in its manufacturing process in

underground storage tanks at the Site. After discovering

contamination in the groundwater near those tanks, Sola

removed the tanks and has been responsible for cleaning

up the remaining volatile organic compound (VOC)

contamination ever since. The Sola Site was listed on the

National Priorities List (or Superfund List) in February

1990.

The aquifer is used as the source of drinking water for the

City of Petaluma. One of the City's groundwater extraction wells was located near the Sola Site, but it was not

impacted by the contamination at the Sola Site. However,

the well was shut down so as not to interfere with groundwater clean-up efforts.
In 1991, EPA decided that the groundwater treatment

system Sola had been operating should be expanded. Sola

complied and operated the expanded system for another six

years. Eventually, however, the system became less and

less effective, and Sola stopped operating it in 1997. Since

then, the levels of contamination in the groundwater have

continued to decline, and only one small area of contamination remains. EPA is now proposing to adopt a different

approach to address the clean-up - or "remediation" - of

that small area.

EPA selected the original clean-up plan and will select this

proposed amendment in accordance with Section 117 of

the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), as amended, 42 U.S.C.

§ 117, and 40 C.F.R. § 300.435(c)(2)(ii) of the National Oil

and Hazardous Substances Pollution Contingency Plan

(NCP). EPA is the lead agency responsible for directing

the CERCLA remediation process; the San Francisco Bay

Regional Water Quality Control Board (Regional Board) is

the support agency. This Proposed Plan is being coordinated with the Regional Board.

This Proposed Plan describes two alternative methods for

achieving the clean-up standards at the Site. The Plan then

identifies EPA's preferred alternative, explains EPA's

rationale for this preference, and presents the key underlying facts. Further information can be found in the project's

publicly available Administrative Record. The public is

invited to participate in the remedy amendment process

and submit comments on the Proposed Plan.

Site Background

As noted above, Sola manufactured eyeglass lenses at the

Site for over 20 years. Its facility was comprised of one

manufacturing building and an adjoining administration

office building. Six 1,000-gallon underground storage

tanks (USTs) were located behind the north corner of the

manufacturing facility. The tanks were used to store

solvents such as 1,1,1-trichloroethane (1,1,1-TCA),

acetone and methanol.

Figure 1: Sola Optical Superfund Site location

Page 2 Sola Optical USA, Inc. Superfund Site
In 1982, Sola found low concentrations of VOC contamination in the groundwater beneath its property near the six

USTs. In 1983, the Regional Board directed Sola to

investigate the groundwater contamination at the Site.

Sola identified the following chemicals in the groundwater: 1,1-dichloroethane (1,1-DCA), 1,1-dichloroethene

(1,1-DCE), methylene chloride, and 1,1,1-TCA. These

chemicals appeared to have originated from the gravel

surrounding the tank and adjacent soils. In 1985, Sola

removed the six USTs, the surrounding gravel and several

feet of soil from the sides and bottom of the excavation.

Further investigation revealed the extent of the groundwater contamination. In 1987, the Regional Board ordered

Sola to construct and operate a groundwater extraction and

treatment (GWET) system. The treated groundwater was

discharged into Adobe Creek, just northwest of the Site,

under a permit from the Regional Board. The GWET

system operated from 1988 through 1997.

In 1989, EPA became the lead agency, and took charge of

directing remedial activities at the Site. One step in that

process was adding the Site to the National Priorities List,

which occurred on February 21, 1990. Pursuant to an

administrative order, Sola conducted further environmental

sampling and completed a feasibility study of clean-up

options in 1991. Based on that study and its own risk

assessment, EPA issued a Record of Decision (ROD),

which documented its determination that an expanded

GWET system was the most appropriate method for

remediating contamination at the Site. The enhanced

GWET system consisted of the following elements:

• Operation of the eight existing extraction wells

• Construction and operation of two additional

shallow extraction wells

• Conversion of two existing monitoring wells to

deep extraction wells

• Construction and operation of additional

piping for new and converted wells

• On-site treatment and off-site discharge to

either the nearby creek or to the City of

Petaluma sewage treatment system.

The enhanced system began operating in 1992 and was

expected to restore the shallow groundwater to clean-up

standards within 15-20 years.

Initially, concentrations of VOC contamination at the Site

decreased significantly. By 1997, however, the rate of

contaminant reduction slowed to almost zero. Groundwater monitoring data at four wells showed that concentrations of two contaminants - 1,1-DCE and 1,1,-DC A -

appeared to have stabilized at levels above the clean-up

standards. The extraction and treatment system was no

longer effectively removing these low-level contaminants

from the groundwater. At that point, Sola requested and

received permission to shut off the GWET system. For the

next two years, Sola sampled and analyzed the wells

frequently to ensure that contaminant levels did not

increase or "rebound." When contaminant levels continued to slowly decline without extraction and treatment,

Sola presented the data and technical analysis to EPA and

received permission to decommission the GWET system.

Sola continued to monitor the groundwater contamination

biannually thereafter. In 2001, Sola analyzed the naturally

occurring changes to the contamination that had been

observed since the decommissioning of the extraction

system. EPA approved the analysis in 2002.

Current Status of Cleanup

By 2002, only two wells reflected contamination above

the clean-up standards: well E-5 and well W-27. Well E-5

showed concentrations of 1,1-DCE above the clean-up

standard until 2004, when the level dropped below, and has

consistently remained below, the standard. Well W-27 is

now the only well that still shows concentrations above the

standard for any contaminant. As of December 2006, the

concentration of 1,1-DCA was 12 parts per billion, as

compared to the clean-up standard of 5 parts per billion.

This is likely due to the fact that W-27 is directly down

gradient from the location of the original contaminant

release, and the last of the contaminants have slowly been

released from the soils and flowed down to W-27.

Groundwater data reflect that the contaminant concentrations in W-27 initially increased when the GWET system

was decommissioned, but have since been declining

steadily. For the past two years, the concentration of 1,1 -

DCA has declined from 22 parts per billion to 12 parts per

billion, indicating that natural processes are reducing

levels of contaminants. None of the other monitoring

wells have detectable levels of any contamination above

any of the other VOC clean-up standards. Based on this

data, the area of remaining contamination appears to

extend across one acre or less in the shallow aquifer.

Institutional Controls

Institutional controls are actions, such as legal controls,

that help minimize the potential for human exposure to

contamination at Superfund sites by ensuring appropriate

land or resource use or restrictions. One common institutional control is a restrictive covenant which is an agreement, recorded with the county recorder's office, whereby

a land owner agrees to restrict the use of his or her property. In its 1991 health risk assessment, EPA recommended

January 2007 PageS
that institutional controls be implemented at the Site to

prevent any use of the contaminated groundwater for

drinking water supplies before it is cleaned up to drinking

water standards. The remedy selected in the 1991 ROD,

however, did not include institutional controls. EPA now

proposes to add institutional controls to the remedy.

Summary of Site Risks

In 1991, EPA prepared a risk assessment to evaluate the

human health and environmental risks posed by contamination at the site.

Human Health Risks

A human health risk assessment begins by identifying the

chemical contaminants that exist in the environment in

sufficient quantities to cause a potential concern. Next, the

assessment evaluates the pathways through which the

chemicals can travel from the environment to humans.

Then it estimates the duration of possible chemical exposure to humans. Finally, it uses all of this information to

calculate a human health risk. This risk is presented in two

parts, the carcinogenic effects (cancer-causing effects), and

the non-carcinogenic effects (all other health effects

besides cancer). The carcinogenic effect is shown in terms

of an additional 1 in a million chance of contracting

cancer, above the normal rate, from the chemical exposure.

The non-carcinogenic effect is shown as a hazard quotient;

values greater than 1 indicate that an effect on human

health will occur, and less than 1 indicates that no effect

will occur.

The 1991 risk assessment for the Site identified the following 12 volatile organic compounds as posing a potential

concern at the Site: acetone, butanone, 1,1-dichloroethane,

1,2-dichloroethane, 1,1-dichloroethene, freon 113,4-

methyl-2-pentanone, tetrachloroethene, toluene, 1,1,1-

trichloroethane, 1,1,2-trichloroethane, trichloroethene.

VOCs are extremely volatile, meaning they vaporize easily

and thus constantly move from one medium to another, for

example from soil to water or air.

The assessment established that the main pathway through

which humans could be exposed to these chemicals is

through their homes. If residents were to use groundwater

for home use, they might drink the contaminated water or

absorb it through their skin. Any flow of water from a

faucet or showerhead could release contaminants into

indoor air where residents might inhale them. The chemicals could also move into indoor air from the groundwater

and soil beneath any homes in a process known as "vapor

intrusion." Note that this potential exposure is based on a

hypothetical future residential use. The Site is currently

used for light industrial/commercial purposes, and the

owners of the Site property do not plan any residential

uses. Also, the existing plume of groundwater contamination does not extend below any residences, and no drinking

water wells pump near the plume. The Site and the

surrounding properties receive water from the City of

Petaluma's municipal water supply, which is not impacted

by the site.

The assessment calculated that a person who lived in a

house directly above the contamination and who was

exposed to the resulting vapor intrusion all of his or her

life would have an excess cancer risk of 9 in 1,000,000.

The national average rate of cancer from all causes is 1 in

4. The calculated "excess" cancer risk means that if a

million people were exposed to this amount of contamination for their lifetimes, there might be nine additional cases

of cancer. The assessment concluded that a person would

not experience any non-carcinogenic health effects.

The assessment also calculated that a person who used the

contaminated groundwater as residential water supply over

the course of his or her entire life would have an additional

1 in 10,000 risk of contracting cancer. The assessment

concluded that this person would not experience any noncarcinogenic health effects.

Subsequent Risk Evaluation

Additional risk evaluations were conducted in 2005 as part

of the Five-Year Review. EPA performed a screening level

evaluation of the potential for remaining levels of contaminants to cause negative health effects either by entering

commercial buildings via vapor intrusion or through

human ingestion of home-grown produce.

To evaluate the potential risk of vapor intrusion, EPA

compared the current groundwater contaminant concentrations to its published "Target Groundwater Concentrations" (Draft Guidance for Evaluating the Vapor Intrusion

to Indoor Air Pathway from Groundwater and Soils, EPA

OSWER, November 2002, Doc No. EPA530-D-02-004)

and the Regional Board's published "Groundwater Screening Levels for Evaluation of Potential Vapor Intrusion

Concerns" (Screening For Environmental Concerns at

Sites With Contaminated Soil and Groundwater, Regional

Board, February 2005). All current contaminant concentrations in the groundwater were found to be well below

both the target and screening levels. On this basis, EPA

determined that vapor intrusion does not pose a human

health risk at this Site.

Page 4 Sola Optical USA, Inc. Superfund Site
To evaluate the potential effects on gardens and homegrown fruits and vegetables, EPA examined other existing

studies on the subject. Research demonstrates that volatile

chemicals do not build up in the plant tissues even if

contaminated groundwater beneath a garden manages to

reach the plants and the chemicals are absorbed by the

plants. When volatile chemicals move into plant leaves,

they are released through the tiny openings in the plant

leaves where gas exchange occurs and therefore do not

accumulate. Studies have also shown that volatile chemicals taken up through plant roots tend to concentrate in the

cells near the surface of the roots. For root vegetables

such as beets, carrots and potatoes, these cells are typically

lost during washing and peeling of the produce. Plants are

also able to break down or degrade volatile chemicals.

Thus, any such chemicals taken up by the plants may be

present temporarily in the roots and stems of the plant but

are much less likely to be present in the leaves or other

above-ground parts of the plant. In summary, existing

studies indicated that uptake and accumulation of volatile

chemicals in plants, and subsequent exposure to humans

who eat them, would be minimal.

Ecological Risk

As part of the 1991 risk assessment, EPA also prepared an

ecological risk assessment to evaluate possible impacts to

the environment. The ecological assessment focused on

possible impacts on the nearby creek, Adobe Creek. This

creek is the closest surface water body to the Site. At the

time of the assessment, a local group had launched a

project to reintroduce anadromous steelhead trout to the

creek.

EPA examined data from groundwater monitoring wells

between the Sola facility and Adobe Creek. Based on this

data, EPA determined that no contaminants were moving

towards or had reached the creek. The assessment did

determine that if the groundwater extraction system were

not operating, contaminated groundwater from the Sola

facility would flow in the direction of Adobe Creek.

However, the contaminant concentrations in the groundwater beneath the Sola facility were not a concern because

they were below federal surface water quality criteria for

the protection of aquatic life.

Today, the Site is not much different than it was in 1991.

The one area that has not yet attained the groundwater

clean-up standard is located on the parcel adjacent to the

original facility property. This parcel is currently an open

field in the process of being developed for light industrial/

commercial use. Approximately one-third of that property

had been recently graded. The field has not otherwise

changed since the time of the original risk assessment. No

new ecological receptors were found at the Site.

Opportunity for Public

Comment

EPA will accept comments on this Proposed

Plan from January 20, 2007 through February 20,

2007. During that period, written comments can

be submitted to Jose Garcia at EPA (see back page

for contact information). Comments presented at

the Proposed Plan Public Meeting, scheduled for

January 24, 2007, will be recorded.

After EPA reviews public comments the

Agency will formally announce the selected remedy in an amendment to the 1991 ROD (ROD

Amendment). Responses to public comments will

be included in the ROD Amendment. The selected

remedy may differ from the preferred alternative in

this plan as a result of public comments. EPA encourages the public to review the reports in the

Administrative Record and comment on any of the

alternatives presented in this Proposed Plan. A

copy of the Administrative Record is located at the

Petaluma Public Library, 100 Fairgrounds Drive,

Petaluma, California, and at the EPA Region 9 office in San Francisco.

Scope of This Action

This remedy addresses the small portion of the Site where

contamination remains in the groundwater at concentrations exceeding the clean-up goal. Once the already-low

levels of 1,1-DCA have been reduced to the drinking water

standard, Site remediation will be complete, and the Site

may be eligible for deletion from the Superfund List.

Description of Alternatives

The alternatives for completing remediation of this site

are:

(1) No Action;

(2) Groundwater extraction, treatment, and off-site

discharge, with institutional controls; and

(3) Monitored natural attenuation with institutional controls.

Remedial Alternative 1 (RA-1)

RA-l consists of no action being taken, not even monitoring. EPA is required to evaluate this option for comparison

purposes.

January 2007 Page 5
Remedial Action Alternative 2

(RA-2)

RA-2 consists of most of the remedial

action selected in the 1991 ROD (the

GWET system) plus institutional

controls. This alternative would

require extracting groundwater from

the shallow aquifer, treating it on-site

and discharging it off-site into Adobe

Creek. The original GWET system

was dismantled in 1998, so it would

need to be rebuilt if selected in this

ROD Amendment. In addition, this

alternative would require implementation of institutional controls at the

Site. The current owners would be

required to record restrictive covenants which would restrict use of the

groundwater until it meets the California drinking water standard. The

objective of this restriction would be

to prevent uses of the groundwater

that could result in unacceptable

exposure of humans or the environment to the groundwater. This

alternative would take an estimated 18

months to construct a new groundwater treatment system, and would take

an estimated one to three years to

attain the clean-up goal.

Remedial Action Alternative 3

(RA-3)

RA-3 consists of the same institutional controls proposed for RA-2 as

well as adoption of monitored natural

attenuation (MNA) as the method for

achieving Site remediation goals.

MNA is a clean-up approach that

relies on natural processes to reduce

contaminant concentrations and

achieve clean-up objectives within a

reasonable time frame, as compared to

other more active methods. Natural

attenuation includes a variety of

physical, chemical or biological

processes - such as dilution and

chemical breakdown - that, under

favorable conditions, act without

human intervention to reduce the

mass, toxicity, mobility, volume or

concentration of contaminants in the

Overall Protection of Human Health and

the Environment

How risks are eliminated, reduced or controlled through

treatment, engineering or institutional controls.

Compliance with Applicable or Relevant

and Appropriate Requirements (ARARs)

Federal and state environmental statutes met

and/or grounds for waiver provided.

Long-term Effectiveness

Maintain reliable protection of human health and the

environment over time, once cleanup goals are met.

29)

:;i -.-i. Reduction of Toxicity, Mobility or

«f| '""n Volume (TMV) Through Treatment

< "^Ij.f Ability of a remedy to reduce the toxicity, mobility

u^ljjj^p„ and volume of the hazardous contaminants present at the site.

Short-term Effectiveness

Protection of human health and the environment

during construction and implementation period.

,*a t Implementability

'"T^K 'I

 Tecnn'cal and

 administrative feasibility of a

'-'isffr' r remed>'' including the availability of materials

0. is :1D ;VS£^ and services needed to carry it out.

Cost <jgjj?t £^>

Estimated capital, operation and Hsl. !igrt

maintenance costs of each alternative.

/ \

A

 State Acceptance

State concurs with, opposes or has no

comment on the preferred alternative.

Community Acceptance

Community concerns addressed; community

preferences considered.

Figure 2: Diagram of

EPA's 9 Remedy Criteria

groundwater. This alternative would take no additional time to construct since

only the existing monitoring wells will be necessary. EPA estimates that this

alternative will achieve the clean-up standards within one to three years.

Evaluation of Alternatives

The purpose of this analysis is to compare the remedial alternatives. This

analysis examines the three remedial action alternatives using the nine evaluation criteria established in the National Contingency Plan, 40 CFR §

300.430(e)(9). The resulting strengths and weaknesses of the alternatives are

then weighed to identify the alternative providing the best balance among the

nine criteria. The nine criteria and the relative performance of the alternatives

in relation to each criterion and each other are summarized in Table 1.

Page6 Sola Optical USA, Inc. Superfund Site
SOLA OPTICAL USA, INC. CLEAN-UP

ALTERNATIVE EVALUATION TABLE

Evaluation Criteria

Alternative 1

No Action

Alternative 2

Groundwater

Extraction &

Treatment,

Institutional Controls

Overall Protect!veness O

Compliance with

State and Federal

Requirements (ARARs)

O

Long-term

Effectiveness

Implementability

Short-term

Effectiveness O

* \ <, ' ,'- i*fn "t /7T^, r' <t

I'l 't ..^i^t*«.''!'.'

 (<

 i i r

Reduction of Toxicity,

Mobility,or Volume by

Treatment

fr'^rr •*"

' f'4:: iiJ'^tf1'"

Estimated Cost,

Present Worth $0 $572,000

". I'"'

-•"• •

State Agency

Acceptance

The State has no comments on EPA's Proposed Plan and ROD

Amendment.

Community

Acceptance

Community acceptance of the preferred alternatives will be

evaluated after the public comment period.

I = Fully meets criteria = Partially meets criteria QJ) = Does not meet criteria

Table 1: Sola clean-up alternatives comparison

January 2007 Page 7
EPA's Preferred Alternative

After evaluating the clean-up options, EPA prefers monitored natural attenuation with institutional controls (RA-3) as the

remedy that provides the best balance of the criteria. EPA expects RA-3 to satisfy the following statutory requirements

of CERCLA, Section 121(b): (1) be protective of human health and the environment; (2) comply with ARARs (or justify

a waiver); (3) be cost-effective; (4) utilize permanent solutions and alternative treatment technologies or resource recovery technologies to the maximum extent practicable; and (5) satisfy the preference for treatment as a principal element.

Once the clean-up standard for 1,1-DCA has been reached, EPA believes that no contamination above clean-up levels

will remain onsite, and any use restrictions may be lifted.

Figure 3: Groundwater under treatment through natural attenuation. In natural attenuation, one mechanism at

work is the break-down of contamination by natural bacteria in the ground, depicted conceptually in this figure.

Page 8 Sola Optical USA, Inc. Superfund Site
For More Information

If you have questions or comments regarding the

Sola Optical USA, Inc. Superfund Site, please contact:

Dante Rodriguez

Remedial Project Manager

U.S. EPA, Region 9

75 Hawthorne St. (SFD-7-1)

San Francisco, CA 94105

email: Rodriguez.dante@epa.gov

phone: (415) 972-3166

fax:(415)947-3526

Jose Garcia

Community Involvement Coordinator

U.S. EPA, Region 9

75 Hawthorne St. (SFD-3)

San Francisco, CA 94105

email: garcia.jose@epa.gov

Phone:(415)972-3331

fax:(415)947-3528

You may also call EPA's toll-free Superfund hotline and leave

a message that will be forwarded to the appropriate EPA staff.

The hotline number is 1-800-231-3075.

Site Repository

Petaluma Public Library

100 Fairgrounds Drive

Petaluma, California

(707) 763-9801

Hours: Tues-Wed 10:00 a.m. - 9:00 p.m.

Mon, Thurs-Sat 10:00 a.m. - 6:00 p.m.

EPA Superfund Records Center

95 Hawthorne St., 4th Floor

San Francisco, CA 94105

(415)536-2000 Hours: Mon-Fri: 8 a.m. - 5 p.m.

For more site information visit the EPA Region 9 web page

www.epa.gov/region09/waste/sfund/superfundsites.html,

select "Site Overviews" and click on Sola Optical USA, Inc.

January 2007 Page 9
is Amending the Clean-up

Contaminated Groundwater at Sola Optical USA,

Inc. Superfund Site

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United States Environmental Protection Agency

Region 9

75 Hawthorne Street (SFD-3)

San Francisco, CA 94105

Attn: Jose Garcia (SOLA 1/07)

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Page 10 Sola Optical USA, Inc. Superfund Site