Skip directly to search Skip directly to A to Z list Skip directly to site content

PUBLIC HEALTH ASSESSMENT

SOLA OPTICAL USA, INC.
PETALUMA, SONOMA COUNTY, CALIFORNIA


ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

The tables in this section list the contaminants of concern. We evaluate these contaminants in the subsequent sections of the Public Health Assessment and determine whether exposure to them has public health significance. ATSDR selects and discusses these contaminants based upon the following factors (7):

  1. Concentrations of contaminants on and off the site.
  2. Field data quality, laboratory data quality, and sample design.
  3. Comparison of on-site and off-site concentrations with background concentrations, if available.
  4. Comparison of on-site and off-site concentrations with public health assessment comparison values for (1) noncarcinogenic endpoints and (2) carcinogenic endpoints.
  5. Community health concerns.

In the following sections dealing with On-site Contamination subsection and the Off-site Contamination, the listing of a contaminant does not mean that it will cause adverse health effects from exposures. Instead, the list indicates which contaminants will be evaluated further in the Public Health Assessment. When selected as a contaminant of concern in one medium, that contaminant will be reported in all media.

The data tables include the following acronyms:

EMEG = ATSDR Environmental Media Evaluation Guide
CREG = ATSDR Cancer Risk Evaluation Guide
NREG = Noncancer Risk Evaluation Guide
EPA MCLG = EPA Maximum Contaminant Level Goal
EPA MCL = EPA Maximum Contaminant Level
CA MCL = CDHS Maximum Contaminant Level
ppm = parts per million (equivalent to milligram per kilogram, mg/kg)
ppb = parts per billion (equivalent to microgram per liter, µg/L)

Comparison values for the public health assessment are contaminant concentrations in specific media that are used to select contaminants for further evaluation. EMEGS are media-specific values developed by ATSDR to serve as an aid in selecting environmental contaminants that need to be further evaluated for potential health impacts. EMEGs are based on noncarcinogenic health endpoints and do not consider carcinogenic effects. CREGs are media-specific values developed by ATSDR to serve as an aid in selecting contaminants for follow-up that are potential carcinogens. CREGs are based on EPA cancer slope factors which give an indication of the relative carcinogenic potency of a particular chemical. NREGs are similar to EMEGs, in that they are evaluating the noncarcinogenic effects of a particular chemical. NREGs are derived using the EPA Reference Dose (RfD). The RfD is an estimate of a daily exposure to a particular compound that is unlikely to cause adverse, noncarcinogenic health effects.

EPA's Maximum Contaminant Level Goal (MCLG) is a drinking water health goal, that represents the concentration that no known or anticipated adverse effect on the health of persons should occur, including an adequate margin of safety. Maximum Contaminant Levels (MCLs) represent contaminant concentrations that EPA or CDHS deems protective of public health (considering the availability and economics of water treatment technology) over a lifetime (70 years) at an exposure rate of 2 liters water per day. While MCLs are regulatory concentrations, EMEGs, CREGs, NREGs, and MCLGs are not.

Toxic Chemical Release Inventory

On-going facility and/or surrounding facilities emissions may be contributing an additional environmental burden to the nearby population. Therefore, the CDHS staff searched the Toxic Chemical Release Inventory (TRI) for the years 1987, 1988, and 1989 (the years for which TRI data is currently available). The TRI contains information on estimated annual releases (emission rates) of toxic chemicals to the environment (via air, water, soil, or underground injection) whether these releases are routine releases, spills and other accidental releases, or occasional releases from normal operation. Toxic chemical release information is submitted to the EPA by certain industries as mandated under the Emergency Planning and Community Right-to Know Act of 1986.

As provided in TRI, Sola reported in 1987 that the Sola facility released 58,600 pounds of acetone into the air (8). No other facilities in the one zip code area surrounding the Sola facility reported any releases in 1987 (8).

As provided in TRI, Sola reported in 1988 that the Sola facility released 20,800 pounds of acetone into the air (9). No other facilities in the one zip code area surrounding the Sola facility reported any releases in 1988 (9).

As provided in TRI, Sola reported in 1989 that the Sola facility released 32,818 pounds of acetone into the air (10). No other facilities in the one zip code area surrounding the Sola facility reported any releases in 1989 (10).

These releases are from typical operations occurring at the plant and are not as a result of the underground tank/spillage problem.

A. ON-SITE CONTAMINATION

Subsurface Soil

Sola began soil sampling in 1984 (1). This limited sampling did not measure any VOCs, but the sampling locations were situated away from the Sola building in the field to the south. In July 1985, Sola removed all six underground solvent storage tanks that had been located next to the building (Figure 2). The removal of the tanks reportedly included the excavation of the gravel backfill and an additional 3 feet of native soil from the sides and bottom of the tank excavation. No evidence of leakage was observed on the tanks upon their removal. The contractors that did the removal observed oxidation of tank-filling pipes and staining of gravel around the filling pipes.

Sola collected subsurface (6-8 feet below ground surface) soil samples after the excavation and before backfilling (1). These samples revealed a high level of acetone in the eastern wall of the excavation, so Sola excavated an additional two feet of soil along this wall of the excavation pit. Subsurface soil sampling after this additional excavation revealed even higher levels of acetone (July 29, 1985, Table I). Acetone is the only contaminant of concern remaining in the soil (Table I) because it exceeds its comparison value (NREG).

Sola directed two rounds of soil-gas sampling: August 1986 and April 1990 (1). The distribution and quantity of VOCs in the soil gas demonstrated that there were no other point sources.

Sola directed additional soil sampling in March 1988 and in April 1990 (1). At two locations next to the excavated area low levels of acetone were detected in the 1990 sampling (Table I).

TABLE I. POLLUTANTS IN ON-SITE SUBSURFACE SOIL
AT THE SOLA OPTICAL SITE*


Contaminant Before
excavation
(July/1985)
After
excavation
(July/1985)
After
excavation
(April/1990)
Comparison
Value
(ppm);Source
Contaminant of Concern
in Soil
Acetone 48 780 4.6 200; NREG Yes
1,1-Dichloroethane nd na nd 200; NREG
1,2-Dichloroethane nd na nd 8; CREG
1,1-Dichloroethylene nd na nd 1 CREG
20; EMEG

1,1,1-Trichloroethane nd na nd 180; NREG
Trichloroethylene nd na nd 200; EMEG (i)

* maximum levels reported in mg/kg= miligrams per kilogram; (equivalent to ppm).
nd: not detected
na: not analyzed

Groundwater - Monitoring Wells

Starting in late 1986, Sola installed monitoring wells on the Sola property to assess the extent and severity of the migration of contaminants from the location of the former underground storage tank (1). Currently, 31 wells are being monitored. The shallow (S), intermediate (I), deep (D1) deeper (D2), and deepest (D3) wells are or have been contaminated with organic compounds (Table II)(3). Concentrations of 1,1-dichloroethane, 1,2-dichloroethane, 1,1-dichloroethylene, 1,1,1-trichloroethane, and trichloroethylene exceed or have exceeded health comparison values (Table II) and are therefore considered chemicals of concern in on-site groundwater.

Municipal wells:

The Sola City well is located on the northern portion of the property. The well has a screened interval from 60 to 280 feet below ground surface. Since 1986, Sola has sampled the Sola City well on an annual basis (3). No VOCs have been detected with the exception of a singular detection of tetrachloroethylene (0.7 ppb) in a sample collected in August 1987 (3).

B. OFF-SITE CONTAMINATION

Groundwater - Monitoring wells

Sola has installed 7 monitoring wells (6 are still operational) to investigate the horizontal and vertical extent of off-site groundwater contamination (1). Five of these monitoring wells (1 in the shallow, 2 in the intermediate, 1 in the deep, and 1 in the deepest aquifer) are located to the west of Cader Lane. The other two off-site Sola monitoring wells are located beside the Petaluma Station 5 City Well; the shallow monitoring well is no longer operational whereas an intermediate well is analyzed periodically. According to these monitoring wells, no VOCs have migrated off-site (3).

A shallow monitoring well was installed off the southwestern corner of Sola property by the Lakeville Business Park owners. This well is now sampled by Sola on a regular basis and no VOCs have been detected in the water (3).

The owner of the private, undeveloped property to the south of the Sola installed four shallow wells. No VOCs were detected in any of the four wells when the water was sampled in February 1991 (11).

Groundwater - Private wells

The Stero well, a deep, industrial well, is located approximately 1,000 feet west of the Sola facility (Figure 1). Sola has sampled the Stero well on a semi-annual basis since April, 1987. Low concentrations of VOCs (less than 2 ppb) were detected in 1987 and 1988 (3). A shallow well (called the Crandell well), located southwest of the Sola property, was used for domestic purposes until the property was abandoned in 1986. Sola has sampled the Crandell well on a semi-annual basis since February, 1987. No VOCs have been detected with exception of a singular detection of tetrachloroethylene (1 ppb) in a sample collected in August 1987 (3).

Groundwater - Municipal wells

The City of Petaluma Station 5 well is located 300 feet north of the site at Lakeville Highway and Frates Road. The well has a screened interval from 180 to 512 feet below ground surface. From 1986 to 1988, Sola sampled the Station 5 well. Low levels of VOCs were detected: up to 2 ppb 1,1-dichloroethylene, 0.9 ppb 1,1-dichloroethane, and 3.2 ppb 1,1,1-trichloroethane (3).


TABLE II. ON-SITE GROUNDWATER CONTAMINATION IN MONITORING WELLS AT THE SOLA OPTICAL SITE

Contaminant Aquifer Maximum
Historical
Concentration(a)
(ppb)
Current
Maximum
Concentration(b)
(ppb)
Comparison
Value
(ppb);
Source
On-site
Groundwater
Contaminant
of Concern
Acetone S-D3 na na 1000; NREG
1,1-Dichloroethane S
I
D1
D2
D3
680
0.8
2
1
1
210
nd
0.5
nd
nd
1000; NREG
5; CA MCL
Yes
1,2-Dichloroethane S
I
D1
D2
D3
11
nd
3
2
nd
1
nd
nd
nd
nd
0.4; CREG
0.5; CA MCL
5; EPA MCL
Yes
1,1-Dichloroethylene S
I
D1
D2
D3
2400
20
25
26
4
240
9
7
5
nd
90; EMEG
0.06; CREG
6; CA MCL
7; EPA MCL & MCLG
Yes
1,1,1-Trichloroethane S
I
D1
D2
D3
1500
11
11
11
4
110
5
4
4
nd
900; NREG
200; CA & EPA
MCL and MCLG
Yes
Trichloroethylene S
I
D1
D2
D3
4
24
nd
nd
1
nd
24
nd
nd
nd
3; CREG
5; CA & EPA MCL
Yes

(a) Historical values from 1986 - Feb. 1991 monitoring well sampling reports.
(b) Current values from February, 1991 monitoring well sampling.
nd: Not detected
na: Not analyzed

C. QUALITY ASSURANCE AND QUALITY CONTROL (QA/QC)

ATSDR presumes that site investigation protocols and analytical data have been reviewed and accepted by the agencies for which the work is being performed. The data used in the preparation of this Public Health Assessment have been reviewed and qualified appropriately.The completeness and reliability of relevant reference information determines the validity of the conclusions drawn in this Public Health Assessment.

D. PHYSICAL AND OTHER HAZARDS

No physical hazards were noted to be present at the site during the last site visit.


PATHWAYS ANALYSES

A. ENVIRONMENTAL PATHWAYS (FATE AND TRANSPORT)

Surface soil

Since the six underground solvent storage tanks did not show any signs of leakage when they were removed, Sola claims that the subsurface soil and groundwater contamination might have resulted from accidental spillages near /or leakage from the fill pipes of the six underground storage tanks (1). Almost no data address the question of surface soil contamination. ATSDR/CDHS is concerned about the lack of information regarding surface soil contamination, although we do recognize that a risk associated with skin contact or fugitive dust generation is probably minimal or nonexistent because the soils are paved and landscaped.

Subsurface soil

There are no plausible exposure scenarios presently existing from the subsurface soil contamination that might still exist at the Sola site. Acetone has been found in three separate sampling rounds. No soil remediation is planned.

The possibility that human exposure to contaminants of concern occurred during past soil remediation is low because the removal was carried out by trained hazardous waste technicians. The same precautions should be undertaken if any further soil remediation such as the excavation, transport, and disposal of the contaminated soils does occur in the future.

Groundwater

The current extraction system does not capture the entire plume of contaminated groundwater (1). Based on measurements of estimated groundwater capture of the current extraction system, shallow and intermediate-depth VOC-contaminated groundwater will not migrate off-site while the current system is operating (6). However, the VOC-affected groundwater in deeper sediments is not within the capture area of the current extraction system (6). The clean-up plan calls for the conversion of several deeper monitoring wells to extraction wells (6). Additionally, several additional shallow extraction wells will be added to reduce the estimated cleanup time to 15 to 20 years (6).

There are four wells near the Sola property that are not monitoring wells. All of these have had at least one detection of very low levels of VOCs. No one is currently drinking the water from these wells.

Concentrations of VOCs found in the Station 5 well water have not exceeded the drinking waters standards for those compounds. Additionally, the water from this well is diluted with other well water before it is delivered to the consumer. Thus, no significant past exposures from the domestic use of municipal well water would be expected. In order to be protective of health and increase the capture of the contaminated groundwater by the plume, the city discontinued operation of Station 5 well in June 1988.

Surface water

Contamination of any surface water such as Adobe Creek or the Petaluma River via soil erosion and overland runoff is unlikely to occur since any contaminated soil that might remain is covered by asphalt.

Groundwater movement is in a southwest direction towards Adobe Creek and the Petaluma River. However, the groundwater contamination has been isolated by the current groundwater extraction system to the Sola property. Therefore there will be no impact on either Adobe Creek or the Petaluma River.

Sola may treat the groundwater using an aqueous phase carbon absorption system and discharge to Adobe Creek. Alternatively, Sola may discharge the treated or untreated water to the city sewage treatment plant. Sola may only discharge untreated groundwater to the sewage treatment plant if it meets certain water quality limitations.

Air

VOCs in the subsurface soil may diffuse downward through the subsurface soil to the groundwater. Alternatively, chlorinated VOCs in the subsurface soil may diffuse upward through the subsurface and surface soils, ultimately being released to the ambient air or move into confined spaces such as the Sola facility.

Sola has installed an aqueous phase carbon absorption groundwater extraction system on-site which results in negligible release of contaminants to the air.

B. HUMAN EXPOSURE PATHWAYS

A potential exposure pathway that may have occurred and may be occurring:

*Inhalation of organic compounds volatilizing from on-site contaminated groundwater and soil.
It is likely that migration of organic chemical compounds from on-site contaminated groundwater and contaminated soil may be occurring within the Sola facility. A theoretical indoor-air model needs to be developed for the potential exposure of on-site workers to compounds volatilizing from the contaminated groundwater and soil and accumulating within the Sola facility. As an alternative, CDHS reviewed the risk assessment developed in the Draft Public Health Risk Assessment for future residents living on the Sola property inhaling VOCs migrating from the contaminated groundwater (2). Air concentrations were modeled from nearby subsurface soil gas concentrations (2). The model uses various parameters including: 1) area of infiltration (crawlspace or crack around perimeter of home), 2) the fraction of air that infiltrates from the crawlspace, 3) the air exchange rate of the home, and 4) the air-filled porosity of the soil. While this model is not exactly the same as a model for on-site worker exposure, it is helpful. The resident exposure times used in the model were longer than those for a typical worker: 8 hours per day, 260 days per year for 10 or 30 years.

A completed exposure pathways that may occur in the future:

*Ingestion of contaminated groundwater and inhalation of volatilized organic compounds from groundwater during showering or other usage of the contaminated groundwater.
The concentrations of site-related contaminants in groundwater (as shown in Table II) are at levels that would be of potential public health concern if the contaminated groundwater was used for drinking purposes (2). The contaminated groundwater is currently not being used for drinking purposes. Regulatory barriers exist to prohibit installation of shallow private wells. Future exposure to groundwater contaminants is unlikely if: (a) the groundwater extraction and treatment system reduces concentrations of site-related contaminants to below levels of health concern and (b) the nearby municipal drinking water well is not used until the groundwater remediation is complete. At this time, sufficient water for municipal use is available from aquifers having higher quality water and water yield.


PUBLIC HEALTH IMPLICATIONS

A. TOXICOLOGICAL EVALUATION

The lifetime excess cancer risk of inhaling VOCs from the shallow groundwater and accumulating in confined spaces was estimated from the addition of the individual risks to the five potential carcinogens: 1,2-dichloroethane, 1,1-dichloroethylene, tetrachloroethylene, 1,1,2-trichloroethane, and trichloroethylene (2). The maximum lifetime excess cancer risk from inhalation of chemicals volatilizing from shallow groundwater for future on-site residents is 9 x 10-6 ("no increased risk")(2). Because workers will experience even less exposure (i.e., an 8-hour day versus 16 or 24-hours at home), current on-site workers are also not expected to be at increased risk for cancer due to the volatile chemicals accumulating within the Sola building.

Potential risks were also assessed for future on-site residents exposure to noncarcinogenic effects (acetone, 1,1-dichloroethane, 1,1-dichloroethylene, Freon 113, tetrachloroethylene, toluene, 1,1,1-trichloroethane, and 1,1,2-trichloroethane)(2). The analyses indicated that the inhalation of organic contaminants from on-site groundwater by future on-site residents would not produce adverse noncancer health effects such as heart or kidney disease, birth defects, etc. (2). Therefore it follows that on-site workers, with less exposure than residents, would not be expected to have noncarcinogenic health effects resulting from inhalation exposures.

B. HEALTH OUTCOME DATA EVALUATION

There have been no epidemiological studies (i.e., evaluations of disease patterns with respect to chemical exposure patterns) conducted to determine whether releases of hazardous substances from the Sola site have resulted in increased disease rates in populations exposed to the contaminants of concern.

The CDHS California Tumor Registry recently released a preliminary report on 1988 cancer incidence data for the entire state including Sonoma County (12). This information may ultimately be useful in a future cancer study, but by itself it should be viewed carefully since historical background cancer rates for the region are unavailable, and data collection during the first year of a cancer registries' operation usually results in underreporting (13). Additionally, due to the presumed biological lag time (usually up to 10 years or more) from exposure to cancer development, the cancer incidence for 1988 would probably not reflect effects of exposure that occurred in previous years at the Sola hazardous waste site.

The CDHS Birth Defects Monitoring Program has been collecting data for Sonoma County since 1987 but the low level of chemical exposure that might arise from this site's contamination does not warrant the utilization of such data (14).

C. COMMUNITY HEALTH CONCERNS EVALUATION

We have addressed each of the community concerns about health as follows:

  1. The wisdom of disposing contaminated water into the sanitary sewer of the City of Petaluma.

    The level of contamination in the discharge water is so low that is poses no public health risk. If the concentrations ever do exceed a set health level than the water must be treated instead of discharged untreated.

  2. Questioning the groundwater quality at a residential area approximately 500 feet from the site.

    The residential areas are upgradient from the site. In addition, the monitoring wells located at shallow and intermediate depths between Sola and the property in question have detected no contamination. The extraction system at Sola is designed to capture and prevent any further migration of the contaminated groundwater.

  3. The cause of contamination of the groundwater at Sola and what Sola was doing to prevent future contamination.

    When the tanks were removed at Sola there were not any leaks in the tanks but the staining on the ground near the tanks suggested that surface spills had occurred at the time of filling the tanks. The tanks in question have been removed. Better transfer of hazardous materials should prevent future problems.

Next Section     Table of Contents

  
 
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Agency for Toxic Substances and Disease Registry, 4770 Buford Hwy NE, Atlanta, GA 30341
Contact CDC: 800-232-4636 / TTY: 888-232-6348

A-Z Index

  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #