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PUBLIC HEALTH ASSESSMENT

CTS PRINTEX
MOUNTAIN VIEW, SANTA CLARA COUNTY, CALIFORNIA


SUMMARY

The California Department of Health Services (CDHS) has prepared this health assessment under cooperative agreement with the U.S. Agency for Toxic Substances and Disease Registry (ATSDR). The CDHS/ATSDR Health Assessment is a mechanism to provide the community with information on the public health implications of specific hazardous waste sites and identify those populations for which further health actions or studies are indicated. The health assessment of CTS Printex, Inc. is based on a review of the Draft Remedial Investigation and Feasibility Study Report (RI/FS)(1) and its subsequent additions and revisions (2, 3), in conjunction with a site visit and consultation with staff from the California Regional Water Quality Control Board (RWQCB). The report serves to update the ATSDR Preliminary Health Assessment for CTS Printex, Inc. (4), completed by ATSDR on February 14, 1991.

The U.S. Environmental Protection Agency placed the former CTS Printex site, located in Mountain View, Santa Clara County, California, on the National Priorities List in February 1990. The California Regional Water Quality Control Board (RWQCB) is the lead governmental agency regulating the cleanup at the CTS Printex site. Printed circuit boards were manufactured at the 1911/1921/1931 Plymouth Street facility (referred to as 1911 Plymouth in health assessment) from 1970 to 1985. Two sources of pollutants identified from this process were the sump and wet floor at 1911 Plymouth which were contaminated with volatile organic compounds (VOCs) and metals (1). In 1985 and 1986, the sump and a total of 290 cubic yards of metal- and VOC-contaminated soil were excavated from beneath the wet floor (1). Various organic contaminants have been detected in on-site and off-site groundwater at levels of human concern (2). However the contaminated groundwater is not a source of drinking water (5, 6). Groundwater extraction and treatment systems have been in operation since 1987 (1). All the buildings formerly occupied by CTS Printex, including 1911 Plymouth, have been returned to the original property owner, ADN Corporation. ADN has renovated these buildings and various businesses occupy them.

Based on information reviewed, ATSDR and CDHS have concluded that the former CTS Printex site is not an apparent public health hazard. Off-site resident and worker exposure is predicted by an indoor air-model but the exposure is at a level below that of health concern. Future exposure to groundwater contaminants is unlikely if: the groundwater extraction and treatment system reduces concentrations of site-related contaminants to below levels of health concern; no future drinking water wells are placed in areas of known contamination until the groundwater remediation is complete; and the active private well located in the contaminant plume is not used for potable purposes. This site is not being considered for follow-up health activities at this time.


BACKGROUND

A. SITE DESCRIPTION AND HISTORY

The CTS Printex site (Figure 1), a former printed circuit board manufacturing facility, is located in the City of Mountain View, Santa Clara County, California, 34 miles south of San Francisco. The U.S. Environmental Protection Agency (EPA) placed the CTS Printex site, Mountain View, CA, on the National Priorities List (NPL) on February 1, 1990. The California Regional Water Quality Control Board (RWQCB), San Francisco Bay Region (Region 2), is the lead agency regulating the CTS Printex cleanup under a formal agreement with the EPA. In 1987, RWQCB first became involved in directing the site investigation and cleanup activities when the site was placed on the state hazardous waste site list. Prior to RWQCB's involvement the California Department of Toxics Substances(1) had directed soil characterization and subsequent excavation/decontamination activities.

Printex Corporation leased the site from ADN Corporation and manufactured printed circuit boards there from 1970 to 1985. In 1981, CTS acquired Printex and renamed itself CTS Printex.

Waste waters containing heavy metals and volatile organic chemicals from the manufacturing process were discharged to the city of Mountain View sewer system. The primary site of both wet and dry manufacturing processes was the "wet floor" building (1911 Plymouth, Figure 2) where waste waters containing heavy metals and organic compounds were released to the "wet floor" and then discharged to the neutralization sump. Other solvents and wastes were placed in drums and disposed of off-site. It is still unclear exactly how the chemicals discharged to the wet floor or the neutralization sump were released to the soil and then the groundwater (1).

In 1985 CTS Printex stopped using the site for manufacturing and returned the property to ADN Corporation. As part of the plant closure process, CTS Printex initiated soil and groundwater investigations. The investigation showed chlorinated volatile organic compounds (VOCs) and metals (copper, lead and nickel) are the major contaminants found in the soil and ground-water samples (1). The highest concentration of organic contaminants in the soils was found around the sump and the "wet floor" of 1911 Plymouth (1). CTS Printex removed the sump and surrounding contaminated soil and the contaminated soil beneath the "wet floor" (Figure 2).

Seven wells on the former CTS Printex site (Figure 2) and 24 off-site wells (Figure 1) currently monitor the VOC contamination in the groundwater. The groundwater monitoring indicates that the plume extends north underneath Interstate 101 (1/8 mile) and west of the site approximately a quarter mile (Figure 1). Remediation of the groundwater began around 1986 (1). Currently there are 3 extraction wells on the former CTS Printex site and 4 extraction wells off-site (Figure 1).

Former CTS Printex facility and surrounding Mountain View area showing contaminated ground-water plume
Figure 1. Former CTS Printex facility and surrounding Mountain View area showing contaminated ground-water plume

Former CTS Printex site showing on-site contaminant investigation and remediation
Figure 2. Former CTS Printex site showing on-site contaminant investigation and remediation


B. SITE VISIT

On March 5, 1991, the staff from the CDHS/ATSDR project, and the project manager from the RWQCB toured the former CTS Printex site and surrounding neighborhood.

The former CTS Printex site consists of a number of high-ceiling one-story buildings now occupied by other businesses. A San Jose Mercury News distribution center currently occupies half of 1911 Plymouth Avenue (the location of the former wet floor). Lenz Tools occupies the other half of 1911 Plymouth. CTC Systems, a software developer, occupies 1921 and 1931 Plymouth Avenue. Light industry and businesses also rent the other four buildings (1904, 1940, and 1950 Colony and 1905 Plymouth) that were once part of the CTS Printex complex.

The area around the building is landscaped with an asphalted parking area and some grasses and shrubs. A fence designed to secure the rear of the 1911/1921/1931 Plymouth building is in place, but the gate is not regularly closed or locked.

C. DEMOGRAPHICS, LAND USE, AND NATURAL RESOURCE USE

Demographics

Over 62,000 people live in Mountain View where the former CTS Printex site is located. According to 1990 census information, approximately 1000 people live in the 10 block area surrounding the plume of groundwater contamination connected with the CTS Printex site (7). The bulk of the population resides on the south side of Highway 101, with the 1990 census information showing only 10 people living on the north side of Interstate Highway 101 (7). Over three-quarters of the population (77%) are 18 years of age or older (7).

The census data show the ethnic/racial breakdown as follows (7): 27% Hispanic (with no other ethnic identification; 51% white; 7% black; 2% American Indian, Eskimo, Aleut; and 13% Asian/Pacific Islander.

Land Use

Land in the area surrounding the site has been used for residential, commercial, and agricultural purposes for many years. The northeast corner of the site is bounded by Permanente Creek and Highway 101. The areas surrounding the rest of the site are zoned for a mixture of multiple family and two family residential units, and general and limited industrial use. Within the four block vicinity of the site, there are 409 housing units with many of these being 14 unit complexes.

The area north of Highway 101 is zoned light industrial and planned community. This type of zoning is designed for research and development, office space, and light manufacturing. No new housing is allowed under this zoning. Within this area approximately 20 acres of land are used for commercial farming. Vegetables are the predominant crop.

Two schools are located northwest within a half mile of the site. The nearest city park is one-half mile southwest of the site.

Natural Resource Use

Shoreline Park is located north of the area with a planned community designation. This park was planned to provide a natural habitat for wildlife in the area. Many species of animals have been observed there including flocks of migratory birds.

Four major water-bearing zones (aquifers)-defined as the A-, B-, intermediate- and C- zones-exist at the site (1). The A-aquifer is the shallowest and the C-aquifer is the deepest of these three zones. The approximate depths (below ground level) at which these zones occur at the CTS Printex site are as follows: A: 10-20 feet; B: 30-40 feet; and intermediate: 60-75 feet. A regional impermeable zone, the B-C aquitard, is reportedly located at a depth range from 100-150 feet below ground level.

The C-aquifer, which supplies most of the municipal water in the region, is located below the regional aquitard.

The only surface water body near the site is Permanente Creek, which is located about 300 to 400 feet east of the site. The Creek is a concrete lined perennial stream which reverts to earthen banks about 300 feet north of the site. During the site visit, the creek was nearly dry. The creek is tidally influenced approximately 1500 feet downstream of the site. The creek could potentially harbor fish and wildlife and be used for recreational purposes.

D. HEALTH OUTCOME DATA

There are two CDHS health outcome registries currently operating in the area of CTS Printex. These will be discussed in the Health Outcome Data Evaluation Section.


COMMUNITY HEALTH CONCERNS

In the early 1980s, following the discovery of the contamination at the Fairchild and IBM facilities in South San Jose, community concern was high regarding groundwater contamination in Santa Clara County. In November 1982, a group of environmental, labor and other organizations concerned about groundwater contamination formed The Silicon Valley Toxics Coalition. Through the Coalition, local residents received extensive information on health issues related to water contamination in the South Bay.

In April 1989, the RWQCB released their Community Relations Plans for Mountain View (8), incorporating the plans for the CTS Printex and Spectra Physics/Teledyne Semiconductor Superfund sites into a single community relations plan.

The plan identified the primary historical concerns in the Santa Clara area as: concern about the quality of drinking water; whether the extent of the problem had been determined; what would happen if the contamination spread; what was being done to clean up the soil and groundwater; what happened to the contaminated groundwater that was pumped out; what the schedule for clean-up is; and how property values would be effected.

In March 1991, RWQCB released Fact Sheet 2 announcing the proposed clean-up plan for the CTS Printex site (9). At the March 20, 1991 RWQCB monthly meeting, the staff presented the recommended alternatives. This marked the beginning of the public comment period designated to end April 19, 1991. No members of the public attended the March 21, 1991 Community Meeting in Mountain View. The RWQCB community relations staff said they had advertised the meeting through their mailing list of over 400 people and placed meeting announcements in the San Jose Mercury News.

The community relations staff from the CDHS ATSDR project spoke with the Director of the Silicon Valley Toxics Coalition, city officials from Mountain View, officials from the Santa Clara County Health Department, two Santa Clara County Board of Supervisors staff persons, and community relations staff from the Environmental Protection Agency and from the CDHS Toxic Substances Control Program. None of the individuals contacted were aware of any recent community health concerns regarding the CTS Printex site. ATSDR staff also met with City of Mountain View staff including the Industrial Waste Program Manager, the Fire Marshall, and representatives from the Public Utilities and Planning Departments. Again, there were no health concerns associated with the site.


ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

The tables in this section list the contaminants of concern. CDHS evaluates these contaminants in the subsequent sections of the Health Assessment and determines whether exposure to the contaminants has public health significance. ATSDR selects and discusses these contaminants based upon the following factors (10):

  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 health assessment comparison values for noncarcinogenic endpoints and carcinogenic endpoints.


  5. Community health concerns.

In the data tables that follow under the On-site Contamination subsection and the Off-site Contamination subsection, the listed 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 Health Assessment.

The data tables include the following acronyms:

EMEG = Environmental Media Evaluation Guide

MCL = 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 health assessment are contaminant concentrations in specific media that are used to select contaminants for further evaluation. These values include ATSDR's Environmental Media Evaluation Guides (EMEGs) for acute (less than 14 days), intermediate (15 to 365 days), and chronic (greater than 365 days) exposure. 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 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.

CTS Printex no longer occupies 1911 Plymouth Street, therefore, TRI was searched by the zip code that includes this building. Seven facilities in the zip code area surrounding 1911 Plymouth Street reported the release of 67,412 pounds of chemicals, primarily volatile organic compounds and acids, into the air in 1987. In 1987, these facilities reportedly released 23,550 pounds of acetone, 127 pounds of xylene, 1,500 pounds of phenol, 13,140 pounds of 1,1,1-trichloroethane, and 27,258 pounds of Freon 113.

Eight facilities in the zip code area surrounding 1911 Plymouth Street reported the release of 124,883 pounds of chemicals, primarily volatile organic compounds and acids, into the air in 1988. In 1988, these facilities reportedly released 3,225 pounds of acetone, 500 pounds of xylene, 1,500 pounds of phenol, 33 pounds formaldehyde, 5,440 pounds of methanol, 51,520 pounds of 1,1,1-trichloroethane, and 3,225 pounds of Freon 113.

Six facilities in the zip code area surrounding 1911 Plymouth Street reported the release of 111,346 pounds of chemicals, primarily volatile organic compounds and acids, into the air in 1989. In 1989, these facilities reportedly released 1,000 pounds of acetone, 500 pounds of xylene, 250 pounds of glycol ethers, and 101,969 pounds of Freon 113.

A. ON-SITE CONTAMINATION

Subsurface soil

In 1985, CTS Printex voluntarily initiated investigations to determine the sources of contamination at the site (1). Soil borings were taken on January 1985 around the sump and on March 1986 from under the wet floor. Samples from five feet deep were analyzed for heavy metal contaminants. In addition, samples taken from soil borings at 4.5 feet depth near the sump (April 1985) and at 5.5 feet depth under the wet floor (October 1986), were analyzed for organic contaminants. A soil boring taken in front of 1950 Colony Street on January 1985 at five feet, was used as a background sample for analysis of metals. Soil around the neutralization sump and wet floor showed the presence of 1,1,1-trichloroethane, 1,1-dichloroethylene and trichloroethylene in various concentrations (Table 1), and lead above background (Table 2).

As a result of these investigations, it was concluded that the soil and groundwater were contaminated and that the contamination had originated from the neutralization sump and wet floor. Copper and lead were selected as indicators of contamination because these metals occurred routinely and at relatively higher concentrations than other constituents in the waste water effluent discharged by Printex to the sanitary sewer (1).

Between August 1985 and August 1986, the neutralization sump and some surrounding soil (70 cubic feet) was excavated and sequentially backfilled to grade level with pea gravel, well-compacted clay, and asphalt (1). In September 1986, about 255 cubic yards of soil were excavated under the wet floor at 1911 Plymouth Street (1).

Following excavation, but before backfilling, soils were again analyzed for the presence of contaminants. In October 1985, soil samples were taken from the excavation wall of the sump and surrounding soil at approximately three feet deep, and on September 1986, samples were taken from the wet floor and the surrounding soil at five feet deep. These samples were analyzed for heavy metal contaminants and results are shown in Table II. On May 1987, soil samples were taken at five and fifteen feet (only five feet sample analyses shown in Table I) from borings at the sump and soil around it and analyzed for organic contaminants (wet floor soil was not analyzed).

Results of the post-remediation analyses showed the presence and levels of various organic contaminants not originally found in the neutralization sump area (see Table I). In addition, the maximum concentrations found for copper and lead after remediation were significantly higher than those observed before excavation and also higher than the background (Table II).

Subsurface soil concentrations (ppb) are taken from the Draft remedial investigation and feasibility study report (1). See text for details. Samples were taken before ("before") and ("after") excavation of soil near the sump and under the wet floor.

TABLE I. ORGANIC CONTAMINANTS IN ON-SITE SUBSURFACE SOIL AT THE CTS PRINTEX SITE
  Sump Wet floor      
  Before (4/85) After (5/87) Before
(10/86)
After
--
EMEG
--

1,1-Dichloroethane
nd
nd-24
na
na
--
1,1,1-Trichloroethane
10
nd-69
na
na
--
1,1-Dichlorethylene
7.3
nd
na
na
400(c)
t-1,2-Dichloroethylene
nd
nd-110
na
na
--
Trichloroethylene
nd
41-220
nd-100
na
100,000(i)

nd=not detected above detection limits
na=not analyzed
c =chronic
i =intermediate


Subsurface soil concentrations (ppb) are taken from the Draft remedial investigation and feasibility study report (1). See text for details. Samples were taken before ("before") and ("after") excavation of soil near the sump and under the wet floor.

TABLE II. HEAVY METAL CONTAMINANTS IN ON-SITE SUBSURFACE SOIL AT THE CTS PRINTEX SITE
    Sump Wet-floor  
  Before
(1/85)
After
(10/85)
Before
(3/86)
After
(9/86)
Bkgd
(1/85)

Copper
41,000
23,000-130,000
20,000-780,000
370,000
45,000
Lead
43,000
27,000- 57,000
nd-40,000
nd
18,000

nd=not detected above detection limits
Background sample taken on 1/85; see text.

Groundwater- Monitoring Wells

Since 1986, CTS Printex has installed 7 on-site monitoring wells to characterize the vertical and horizontal extent of groundwater contamination (Figure 1). The most contaminated wells are located near to or downgradient, north to northwest, from the sump excavation (1). RWCQB is tracking the migration of contaminants through the major water-bearing zones, called aquifers (see Pathways Analyses). The two shallowest aquifers (A and B1) are contaminated with dichloroethane, 1,1,1-trichloroethane, 1,1-dichlorethylene, trans-1,2-dichloroethylene, and trichloroethylene at concentrations exceeding state or federal drinking water standards (Table III).

In addition, CTS Printex periodically analyzes the groundwater from 2 monitoring wells, one in the A- and one in the B-aquifer, for copper, lead, and nickel. These wells are located directly where the source of contamination had existed (rear of 1911 Plymouth). Results shown in Table IV indicate that the concentrations of copper and lead are below Federal and California drinking water standards (MCLs). No drinking water standard exists for nickel. As compared to background levels (monitoring wells located upgradient from the source of contamination), no copper, lead or nickel contamination exists in the on-site groundwater (Table IV).

CTS Printex installed three extraction wells on-site: two draw from the A-aquifer and one draws from the B-aquifer (1). The untreated groundwater is discharged by permit to the City of Mountain View's sanitary sewer system (1).

Data are taken from the quarterly monitoring well report, fourth quarter, 1990 (10). The historical range of contaminant concentrations for each aquifer is given with the highest concentration currently measured in that aquifer given in parenthesis.

TABLE III. ORGANIC CONTAMINANTS IN ON-SITE MONITORING WELLS AT THE CTS PRINTEX SITE
  Drinking Water Standards Aquifer Concentration (ppb)
A B intermediate

1,1- & 1,2-Dichloroethane
0.5a
nd-13(4)
nd-20(nd)
nd
1,1,1-Trichloroethane
200a,b
nd-45(6.2)
nd-13,000(1.8)
nd
1,1-Dichlorethylene
6a
nd-17(1.4)
nd-1000(nd)
nd
t-1,2-Dichloroethylene
10c
nd-36(7.03)
nd-14(4.3)
nd
Trichloroethylene
5a,b
nd-122(20)
1.3-7500(26)
nd

nd=not detected above detection limits
na=not analyzed
a California MCL
b Federal MCL
c proposed California MCL


An historical range of concentrations are given. The maximum concentration level (MCL) is a Federal and/or California drinking water standard.

Data are taken from the quarterly monitoring well report, fourth quarter, 1990 (10).

TABLE IV. COPPER, LEAD, AND NICKEL IN ON-SITE MONITORING WELLS AT THE CTS PRINTEX SITE
      Aquifer Concentration (ppm)
MCL A A-bkgd B B-bkgd

Copper
1.3
nd-0.05
nd-0.06
nd
nd-0.03
Lead
0.05
nd-0.003
nd-0.004
nd
nd-0.005
Nickel
----
nd-0.07
nd-0.07
nd
nd-0.04

nd=not detected above detection limits

Air

On December 10, 1989, CTS Printex had ambient outdoor air samples taken at two locations on the former CTS Printex site (Figure 2). The sampling locations were chosen to evaluate the ambient air above the contaminated site. An upwind, off-site sampling location was used as a reference background. Air samples were collected by drawing a known volume of ambient air into a canister at a predetermined rate for approximately 4.5 hours.

Sampling canisters were placed approximately five feet above the ground. Wind conditions on the sampling day were noted as being breezy to gusty. Only toluene (2.9, 3.0 ppb) was detected in ambient air sampling for organic contaminants(1). Toluene was not detected (<0.5 ppb) in the a "background" sample.

B. OFF-SITE CONTAMINATION

Groundwater - Monitoring wells

Starting in late 1986, CTS Printex installed 24 off-site monitoring wells to assess the extent and severity of the migration of contaminants from the CTS Printex site. The two shallowest aquifers (A and B) were found to be contaminated with organic compounds. Six chlorinated organic compounds identical to those found at the CTS Printex site, have been detected in the groundwater in the most recent monitoring report of selected wells (Table V). Concentrations of dichloroethane, 1,1,1-trichloroethane, 1,1-dichlorethylene, trans-1,2-dichloroethylene, and trichloroethylene, exceed drinking water standards.

In addition, CTS Printex periodically analyzes the groundwater from 2 of the 24 monitoring wells, one in the A- and one in the B-aquifer, for copper, lead, and nickel. These wells are located directly across the street from 1911 Plymouth Street. Results indicate that the concentrations of copper and lead are below Federal and California drinking water standards (Table VI). No drinking water standard exists for nickel.

As compared to background levels (monitoring wells upgradient from the source of contamination), no copper, lead or nickel contamination exists in the off-site groundwater (Table VI).

CTS Printex has installed four extraction wells off-site: two draw from the A-aquifer and two draw from the B-aquifer (Figure 1). The untreated groundwater is discharged by permit into the City of Mountain View's sanitary sewer system (1).

Data are taken from the quarterly monitoring well report, fourth quarter, 1990 (10). The historical range of contaminant concentrations for each aquifer is given with the highest concentration currently measured in that aquifer given in parenthesis.

TABLE V. ORGANIC CONTAMINANTS IN OFF-SITE MONITORING WELLS AT THE CTS PRINTEX SITE
  Drinking Water Standards Aquifer Concentration (ppb)
A B intermediate

1,1- & 1,2-Dichloroethane
0.5a
nd-330(64)
nd-310(310)
nd
1,1,1-Trichloroethane
200a,b
nd-2500(140)
nd-1100(12)
nd-1.0(nd)
1,1-Dichlorethylene
6a
nd-420(47)
nd-350(140)
nd
t-1,2-Dichloroethylene
10c
nd-580(580)
nd-550(550)
nd
Trichloroethylene
5a,b
nd-1500(520)
nd-320(200)
nd

nd=not detected above detection limits
na=not analyzed
a California MCL
b Federal MCL
c proposed California MCL


An historical range of concentrations are given. The maximum concentration level (MCL) is a Federal and/or California drinking water standard.

Data are taken from the quarterly monitoring well report, fourth quarter, 1990 (10).

TABLE VI. COPPER, LEAD, AND NICKEL ANALYSES OF OFF-SITE GROUNDWATER AT THE CTS PRINTEX SITE
      Aquifer Concentration (ppm)
MCL A A-bkgd B B-bkgd

Copper
1.3
nd-0.02
nd-0.06
nd-0.09
nd-0.03
Lead
0.05
nd-0.002
nd-0.004
nd-0.08
nd-0.005
Nickel
----
nd-0.04
nd-0.07
nd-0.16
nd-0.04

nd=not detected above detection limits

Groundwater-Private wells

Table VIII shows the results from water analysis of private wells. Within the contaminant plume there is one well that is considered active by the local water district. CTS Printex sampled this private well, December, 1986 (5). The sample (results shown in Table VII as "within plume and shallow"), taken from a spigot adjacent to the pump house, contained various organic contaminants in concentrations below drinking water standards, except for trans-1,3-dichloropropylene (5). The depth of the well is approximately 76 ft. When this well is pumped, groundwater is primarily drawn from the intermediate permeable zone (60-70 ft), although there is some indications that a fraction may come from the overlying 10-20 ft and 30-40 ft zones. The last reported use of this well was sometime during the last six months of 1987.

CTS Printex has also sampled two other private wells in the area but these wells are not located within the current contaminated plume area. Private well #1 is a deep (265 ft deep) agricultural irrigation well lies approximately a quarter-mile northwest of the CTS Printex contamination. This well draws from the water-bearing intervals of 65 to 85 ft, 205 to 225 ft, and 240 to 255 ft. Analysis of a water sample taken from Private well #1 on January 15, 1988 showed no detectable levels of organic contaminants (shown in Table VII under "outside plume-deep #1)(1).

Private well #2 is another nearby deep (435 ft) agricultural well which is currently not in use due to a broken pump. Analysis of water from deep well #2 sampled on January 15, 1988, revealed the presence of 1,1,1-trichloroethane, trans-1,2-dichloroethylene, and trichloroethylene (results shown in Table VIII as "outside plume-deep #2)(11). On January 1991, analysis of water taken from deep well #2 revealed the presence of the contaminant, 1,2-dichloropropane (see Table VII). A shallower (50 feet deep) agricultural irrigation well on the same property was sampled October, 1987 (results shown in Table VII as "outside plume and shallow"). Trace concentrations of 1,1-dichloroethane and 1,1-dichloroethylene were found in this water sample (6).

See text for references.

TABLE VII. PRIVATE WELL SAMPLING
Well description Within plume Outside plume Drinking Water Standard
Shallow Shallow Deep #1 Deep #2
Sampling date 12/13/86 10/28/87 1/15/88 1/15/88 1/31/91
1,1-Dichloroethane 3.3 1.1 nd nd nd 5a
1,1,1-Trichloroethane 6.2 nd nd 0.51 nd 200b,c
1,1-Dichloroethylene nd 0.26 nd nd nd 6b
t-1,2-Dichloroethylene nd nd nd 0.37 nd 10a
Trichloroethylene nd nd nd 0.1 nd 5b,c
1,2-Dichloropropane nd nd nd nd 0.71 5a
t-1,3-Dichloropropylene 0.91 nd nd nd nd 0.5b

nd=not detected above detection limits
a proposed California MCL
b California MCL
c Federal MCL

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 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 Health Assessment.

D. PHYSICAL AND OTHER HAZARDS

No physical hazards appear to be present at the site.


PATHWAYS ANALYSIS

A. ENVIRONMENTAL PATHWAYS (FATE AND TRANSPORT)

Soil

At present, either asphalt or concrete cover the entire former CTS Printex site, therefore skin contact or fugitive dust generation could not occur.

Inadequate documentation exists regarding subsurface soil contamination prior to and after excavation of either the sump or the wet floor; therefore, it is difficult to establish whether the majority of contaminated soil has been removed. Although the levels of the organic contaminants remaining around the sump are low, the levels remaining below the wet floor are unknown. Elevated copper and lead remain near the sump excavation and copper near the wet floor excavation. While no migration of copper is to be expected based on the leaching tests performed by CTS Printex, the lack of adequate data to elucidate the metal contamination beneath the wet floor is of concern for invasive soil work (e.g., construction activity) that may be performed in the future.

Groundwater

Based on the well monitoring data for the site, it appears that the bulk of the organic chemical contamination is confined to the A- and B-aquifers (Tables III and V). Except for 1,1,1-trichloroethane, no other organic contaminants have been detected in samples from the two monitoring wells drawing from the intermediate zone (Tables III and V).

On-site and off-site monitoring well sampling for copper, lead, and nickel (Tables IV and VI) does confirm the soil leaching tests in suggesting that the copper and lead soil contamination that might remain underneath the former wet floor and around the former sump is not currently impacting the groundwater quality.

Well surveys of the site area indicate the presence of 72 wells not associated with the remediation, although only eight wells are located within the current contaminated plume (5, 6). Of the 72 total wells, 65 wells are inactive; a few of these have been properly destroyed but the majority have been abandoned and not sealed-off (5, 6). The water from the seven active wells is used for agricultural or non-potable purposes (5, 6).

Of the eight wells located within the contaminated plume, seven have been abandoned improperly and the other one is considered active (5, 6). The one active well (shown as "within plume-shallow" in Table VIII) contained detectable levels of various organic contaminants. This well is not used for drinking purposes and the household next to the well is connected to the municipal water system (5, 6). This well pumps primarily from 76 feet below ground surface, although a fraction may come from the overlying 10 to 20 and 30 to 40 foot zones (5, 6).

Two other active agricultural irrigation wells, one shallow well and one deep well, both used for agricultural irrigation, have been sampled and analyzed for organic chemical contamination (Table VIII). Detectable levels of various organic contaminants were found in both wells although the deeper well has been recently tested and found to contain only detectable levels of 1,2-dichloropropane. This chemical has been interpreted as a fumigant used in agriculture and not related to CTS Printex contamination (Table VII).

Another active well has been impacted, but it has not been analyzed for contamination so the nature and extent of contamination is not known. Additionally, there is one inactive but not destroyed well and twelve wells considered abandoned and improperly destroyed that could possibly again be utilized if a functioning pump were attached. This is especially of concern since California has been experiencing a severe drought the past five years and residents are increasingly turning to private wells to supplement rationed water allotment.

Surface Water

Although surface water runoff from the site is discharged to the Permanente Creek, this runoff is not expected to contain appreciable concentrations of site-related contaminants because any residual contamination at the site is confined to soils (surface or subsurface) under asphalt or under the former CTS Printex "wet floor" building.

In addition, contaminated groundwater does not appear to be discharging to Permanente Creek because the direction of the contaminant plume is away from the creek.

Consumable Biota

There are no current, or indicated future, pathways in which consumable biota could be exposed to site-related contaminants. Furthermore, the contaminants detected in the groundwater and subsurface soils are not expected to significantly bioaccumulate in plant or animal tissues.

Air

Chlorinated organic contaminants transported off-site by groundwater may diffuse through the subsurface and surface soils, ultimately being released to the ambient air or confined spaces such as homes or other buildings. Ambient outdoor air monitoring was performed on-site in order to address this issue (1).

Records of the ambient air monitoring indicate measurements were taken five feet off the ground on a windy day. Toluene was the only VOC detected in the ambient air. The monitoring done on that one occasion does not adequately address the off-gassing of compounds from the groundwater through the soil and accumulating in homes.

B. HUMAN EXPOSURE PATHWAYS

Table VIII shows the human exposure pathways that can be expected to have occurred or that may occur at the CTS Printex site:

*Inhalation of organics volatilizing from on-site groundwater (Table VIII)

The evidence of toluene emissions at the CTS Printex site suggests that it is likely that migration of organic chemical contaminants from the on-site contaminated groundwater and contaminated soil may be occurring within 1911/1921/1931 Plymouth Street. A theoretical indoor-air model, similar to that described below, needs to be developed for this potential exposure pathway.

*Inhalation of organics volatilizing from off-site groundwater (Table VIII)

Human exposure is likely, as a result of organic contaminants volatilizing off-site from the contaminated groundwater and accumulating within buildings (residences and off-site businesses). This route can only be proposed, since no adequate soil-gas or air monitoring has been conducted.

A theoretical indoor-air model was used to estimate the air concentrations within single-family residences located above the contaminated plume (2). Air concentrations for an "average case scenario", "plausible maximum scenario", and a "most plausible case" were calculated (2). These scenarios use different assumptions for the parameters: 1). area of infiltration (crawlspace or crack around perimeter of building), 2) the fraction of air that infiltrates from the crawlspace, and/or 3) the air exchange rate of the home or business.

TABLE VIII. POTENTIAL EXPOSURE PATHWAYS
EXPOSURE PATHWAY Time Component Source of Contamination Environmental Media & Transport Point of Exposure Route of Exposure Receptor Population
VOCs volatilizing from groundwater and accumulating in confined spaces Past,
present
and future
Contaminated groundwater from CTS Printex Air Residences Inhalation Residents living above contaminated plume
VOCs volatilizing from groundwater and accumulating in confined spaces Past,
present
and future
Contaminated groundwater from CTS Printex Air Off-site businesses Inhalation Workers employed by businesses above contaminated plume
VOCs volatilizing from groundwater and accumulating in confined spaces Past,
present
and future
Contaminated groundwater from CTS Printex Air On-site businesses Inhalation Workers at 1911/1921/1931 Plymouth
Use contaminated groundwater for potable purposes Future Contaminated groundwater from CTS Printex Drinking water Residences with private wells Ingestion
and
inhalation
Residents living above contaminated plume

Potential future exposure pathways of concern include:

*Ingestion of contaminated groundwater and inhalation of volatilized organics from groundwater during showering or other usage of the contaminated groundwater (Table VIII).

The concentrations of site-related contaminants in groundwater (as shown in Tables III and V) are at levels that would be of potential public health concern if domestic use of the contaminated groundwater occurred. No municipal wells currently exist near the site. There are several private wells in the area or directly within the contaminated groundwater plume, but most of these are not active. Of those wells that are still active, the water pumped from these wells is not currently used for domestic purposes. At this time, sufficient water for municipal use is available from aquifers having higher quality water and water yield. Additionally, regulatory barriers exist to prohibit installation of shallow private wells on-site.


PUBLIC HEALTH IMPLICATIONS

A. TOXICOLOGICAL EVALUATION

Based on the concentrations of organic contaminants accumulating in a house as developed by this model, the risk of developing cancer from inhaling volatilized organic contaminants for current residents living above the contaminated groundwater was calculated (2). The exposure was assumed to be 24 hours per day, 365 days per year for 40 years for residents (2). The exposure was assumed to be 8 hours per day, 260 days per year for 40 years for off-site workers (2).

The potential lifetime excess cancer risk caused by the inhalation of volatilizing organic contaminants from the shallow groundwater was estimated from the addition of the individual risks to the three potential carcinogens, 1,1-dichlorethylene, 1,1-dichloroethane and trichloroethylene.

Lifetime excess cancer risk for off-site residents ranged from 1.8 x 10-8 ("no increased risk") for the least conservative estimate and 2.9 x 10-5 ("no apparent increased risk") for upperbound worst-case conditions (2). Lifetime excess cancer risk for off-site workers ranged from 2.1 x 10-9 ("no increased risk") for the least conservative estimate and 3.5 x 10-6 ("no increased risk") for upperbound worst-case conditions (2). For comparison, EPA considers an excess cancer risk of 1 in 10,000 (1 x 10-4) to 1 in 1,000,000 (1 x 10-6) as appropriate clean-up goals.

No human studies exist that allow us to conclusively determine whether or not trichloroethylene causes cancer in humans. Although animal studies indicate that trichloroethylene may be associated with cancers in rodents, the evidence is not conclusive. At one time, EPA classified trichloroethylene as a probable human carcinogen, basing its classification on sufficient evidence in animal studies. EPA used cancer data from 1982 and 1986 NTP studies. EPA has withdrawn this classification while conducting a review of the carcinogenicity of trichloroethylene. Therefore, until more experimental evidence is available, either from human or animal studies, we cannot determine whether exposure to trichloroethylene is likely to cause cancer. For this public health assessment trichloroethylene was evaluated as a potential carcinogen.

Potential risks were also assessed for the noncarcinogens (trans-1,2-dichloroethylene and 1,1,1-trichloroethane) for residents above the contaminated groundwater plume (2). The analyses indicated that the inhalation of organic contaminants from off-site groundwater would not result in adverse noncarcinogenic effects (2).

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 CTS Printex site have resulted in increased disease rates in populations exposed to the contaminant of concern.

California Tumor Registry

The state's cancer reporting system (CDHS California Tumor Registry) began collecting data for the region that includes the former CTS Printex site and surrounding area in 1988.

The California Tumor Registry released a preliminary report on 1988 data, February 18, 1991 (12). This cancer incidence information may ultimately be useful in a future cancer investigation 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 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 CTS Printex hazardous waste site.

Birth Defects Registry

The CDHS Birth Defects Monitoring Program began collecting data for Santa Clara County in 1983.

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

No community health concerns were identified. Comments from RWQCB were received during the public comment period December 18, 1991 to January 15, 1992 (see Appendix A).


CONCLUSIONS

Based on information reviewed, ATSDR and CDHS have concluded that the former CTS Printex site is not an apparent public health hazard. As noted in the human exposure pathways section above, off-site resident and worker exposure is predicted by an indoor air-model but the exposure is at a level below that of health concern.

Future significant exposure to ground-water contaminants is unlikely if the groundwater extraction and treatment system reduces concentrations of site related contaminants to below levels of health concern, no wells currently in place are used for domestic purposes, and future drinking water wells are not placed in areas of known contamination if groundwater remediation does not clean up contaminants to drinking water standards.


RECOMMENDATIONS

Cease/Reduce Exposure Recommendations

In the areas of known groundwater contamination, implement institutional controls to prevent future use of contaminated aquifers for drinking water supplies until remediation has reduced contaminant concentrations to below levels of health concern.

Notify 72 well-owners in the site area to inform them of the potential chemical hazard of drawing water from their wells.

Site Characterization Recommendations

Implement a monitoring program of the seven active wells in the area of CTS Printex.

Health Activities Recommendation Panel (HARP) Recommendations

In accordance with the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) as amended, the CTS Printex site has been evaluated for follow-up health activities. Although exposure to site contaminants is believed to have occurred in the past and may be currently occurring, the exposures are at durations and concentrations not likely to pose a public health concern. Therefore, this site is not being considered for follow-up health activities at this time. If additional or new information becomes available suggesting that exposure to hazardous substances at concentrations of public health concern is occurring, ATSDR and the California Department of Health Services will re-evaluate this site for any indicated follow-up health activities.


PUBLIC HEALTH ACTION

Based on the recommendations of the HARP, ATSDR is not planning any follow-up health activities at this time.

The Site Cleanup Requirements for CTS Printex adopted by RWQCB and EPA impose institutional controls by way of a deed restriction for use of groundwater beneath the property where the CTS Printex hazardous waste site is located.

Additionally exposure to shallow groundwater is currently limited in the area due to a Santa Clara Valley Water District ordinance which allows no wells of less than 50 feet be drilled.


PREPARERS OF REPORT

Environmental and Health Effects Assessors:

Marilyn C. Underwood, Ph.D.
Toxicologist
Impact Assessment, Inc., Consultant to
Environmental Epidemiology and Toxicology Branch
California Department of Health Services

Diana Lee, M.P.H.
Research Scientist
Environmental Epidemiology and Toxicology Branch
California Department of Health Services

Community Relations Coordinator:

Jane Riggan, M.S.W.
Impact Assessment, Inc., Consultant to
Environmental Epidemiology and Toxicology Branch
California Department of Health Services


ATSDR REGIONAL REPRESENTATIVES

Gwendolyn Eng
Regional Services, Region IX
Office of the Assistant Administer

William Nelson
Regional Services, Region IX
Office of the Assistant Administer


ATSDR TECHNICAL PROJECT OFFICER

Burt J. Cooper, M.S.
Environmental Health Scientist
Division of Health Assessment and Consultation
Remedial Programs Branch, State Programs Section


CERTIFICATION

This public health assessment was prepared by the California Department of Health Services under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the health assessment was initiated.

Burt J. Cooper
Technical Project Officer, SPS, RPB, DHAC


The Division of Health Assessment and Consultation, ATSDR, has reviewed this health assessment and concurs with its findings.

Director, DHAC, ATSDR


REFERENCES

1. Aqua Terra Technologies. Draft remedial investigation and feasibility study report. Former CTS Printex facility., prepared for CTS Corporation. 1991. Mountain View, California.

2. Aqua Terra Technologies. Baseline public health evaluation. Former Printex facility., prepared for CTS Corporation. 1990. Mountain View, California.

3. Aqua Terra Technologies. Revised feasibility study for CTS Printex site, prepared for CTS Corporation. 1990. Mountain View, California.

4. Agency for Toxic Substances and Disease Registry. Preliminary health assessment for CTS Printex, Inc. U.S. Department of Health and Human Services, Public Health Service-1991.

5. Aqua Terra Technologies. Potential well conduit study report. Permanente Creek to Rengstoroff, Colony Street to Charleston Road., prepared for CTS Corporation. 1987. Mountain View.

6. Aqua Terra Technologies. Potential well conduit study report. Permanente Creek to Rengstoroff Avenue, U.S. Highway 101 to Charleston Road, prepared for CTS Corporation. 1987. Mountain View.

7. Census Bureau. Census of housing. U.S. Department of Commerce-1990.

8. California Regional Water Quality Control Board. Community relations plan for superfund sites in the city of Mountain View. Sites included in this plan: CTS Printex and Spectra-Physics/Teledyne Semiconductor. California Water Resources Agency-1989.

9. California Regional Water Quality Control Board. CTS Printex superfund site. Fact sheet no. 2. California Resources Agency-1991.

10. Aqua Terra Technologies. Quarterly Report, fourth quarter 1990, prepared for CTS Corporation. 1991. Mountain View, California.

11. Aqua Terra Technologies. Technical report CAO No. 90-149. Shallow groundwater contamination investigation in the area of monitoring well 34W, prepared for CTS Corporation. 1991. Mountain View, California.

12. Department of Health Services. Cancer incidence and mortality. California, 1988. California Health and Welfare Agency-1991.

13. Epidemiologist, California Tumor Registry. Personnel communication by telephone-March 1, 1991. California Department of Health Services.

14. Epidemiologist, California Birth Defects Monitoring Program. Personnel communication by telephone-March 4, 1991. California Department of Health Services.


APPENDIX A: SUMMARY OF RESPONSE DURING PUBLIC COMMENT PERIOD

  1. California Regional Water Quality Control Board concurred with our conclusion that the CTS Printex site is not an apparent health hazard and with our recommendations regarding exposure reduction. The commentor noted certain exposure reduction actions that are in place.
  2. The particular exposure reduction actions, including institutional deed controls and the existence of a local ordinance prohibiting shallow well drilling cited by RWQCB, have been incorporated into a new section in the Health Assessment called the Public Health Action Plan.

  3. RWQCB noted the involvement of the Department of Toxic Substances Control (DTSC) (formerly the Toxic Substances Control Program within the Department of Health Services) in the site characterization process prior to RWQCB's involvement.
  4. Since no mention of DTSC's involvement in the process had been in the Draft Health Assessment, this information has now been added to the Site Description and History section.

  5. RWQCB reiterated that DTSC in October 1986 deemed the soil data including that for copper and lead as being adequate. Although high levels of cooper remain in the soil around the former sump and the wet-floor, RWQCB pointed out that soil leaching tests carried out by CTS Printex did show that the copper would not be expected to migrate. Additionally, CTS Printex is required to analyze certain on-site and off-site wells periodically for copper and lead to confirm that no migration is occurring.
  6. Our concern for the concentrations of metals in the soil stems not only from a concern for migration from the soil to the groundwater but also for any future construction work or invasive work of any sort where a person might be exposed to the subsurface soil. Thus to the Health Assessment, the concern over the inadequate documentation of subsurface soil contamination remains.


1. Prior to July 19, 1991 the Department of Toxic Substances Control Program (DTSC) was known as the Toxic Substances Control Program with the Department of Health Services. Under a reorganization, the DTSC is now part of the California Environmental Protection Agency (Cal EPA).

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