PUBLIC HEALTH ASSESSMENT

Tucson International Airport
Tucson, Arizona
_________________________

El Vado Residential Site
Health Evaluation of Remediated Residential Soils:
A residential site located adjacent to the Three Hangars Facility
at the Tucson International Airport

CERCLIS # AZD980737530

Prepared By
Arizona Department of Health Services
The Office of Environmental Health

February 24, 1999

Under Cooperative Agreement with the Agency for Toxic Substances and Disease Registry (ATSDR)

EXECUTIVE SUMMARY

The Agency for Toxic Substances and Disease Registry (ATSDR) has asked the Arizona Department of
Health Services (ADHS), Office of Environmental Health, to conduct a health assessment for the off-site
residential area located adjacent to the Tucson Industrial Center (TIC), also known as the 3 Hangars site,
within the larger Tucson International Airport Area Superfund site (TIAA), in Tucson, Arizona. Previous
investigations found that elevated levels of polychlorinated biphenyls (PCBs) in the drainage areas at the TIC
site had migrated off-site into residential areas presenting a health threat to residents. The purpose of this
Public Health Assessment is to evaluate if a public health hazard still exists since the remediation activities
have been conducted at the off-site El Vado residential area.
Remediation activities occurred during the period March to May, 1997. These consisted of the removal of
contaminated surface soil in the backyards of 3 residential properties, vacant areas north and west of a
church, and a vacant lot all located west of Highway 89 between East El Vado and East Corona Roads They
also included the area in the associated drainages west of the 3 Hangars area. The areas were replaced with
clean fill dirt and new landscaping. In addition, voluntary removal actions conducted by the Tucson Airport
Authority (TAA) at the 3 Hangars site included the removal of PCB contaminated pipe sludge from the inlets
to the drain pipes in the 3 Hangars area and plugging the floor drains and other inlets to the drain pipe
systems to prevent future surface water flows from entering the pipe systems and facilitating PCB migration
to off-site areas.
Results from the 31 confirmatory soil samples taken in these areas after the remediation was conducted were
found to be below the Arizona Residential Soil Remediation Level (SRL) of 0.66 mg/kg for PCBs indicating
that all contaminated soil had been removed. (Conestega 1997)
ADHS concludes that no current public health hazard exists as a result of ingestion, dermal, or inhalation
exposures by residents, children, or transients to the post remediated soil in the residential areas on El Vado
Road. Replacement of the top soil with certified clean soil has removed all contact with the soil containing
PCBs eliminating any future public health hazard.

i

SUMMARY
The Agency for Toxic Substances and Disease Registry (ATSDR) has asked the Arizona Department of
Health Services, Office of Environmental Health, to conduct a Public Health Assessment for the off-site
residential area located adjacent to the Tucson Industrial Center (TIC) within the larger Tucson International
Airport Area Superfund site (TIAA), in Tucson, Arizona. Previous investigations found that elevated levels
of polychlorinated biphenyls (PCBs) in the drainage areas at the TIC site had migrated off-site into
residential areas presenting a health hazard to residents. The purpose of this Public Health Assessment is
to evaluate if a public health threat posed by PCBs still exists since the off-site remediation activities have
been conducted at the El Vado residential area.

BACKGROUND
A.
SITE DESCRIPTION AND HISTORY
The TIAA Superfund Site has been the site for various aviation, aerospace, and electronic industrial facilities
since 1942. In May 1983, the TIAA site was added to the National Priorities List (NPL) after the discovery
of a major groundwater plume containing several organic compounds, including trichloroethylene (TCE),
1,1-dichloroethylene (DCE), trans-1,2-dichloroethylene, chloroform, and chromium. (ADHS 1996). The TIC
site, also known as the 3 Hangars site, is located on the central western portion of the TIAA site and is zoned
as industrial property suitable for several types of manufacturing activities. The 3 Hangars area was used
for aircraft modification operations between 1954 - 1960. Currently, it is used by a number of tenants
performing a variety of industrial activities including general aircraft and vehicle maintenance, synthetic
rubber and plastics manufacturing, and charter services. Several other building structures located in this area
include small businesses involved in, but not limited to, aircraft maintenance, overhaul and repair,
sandblasting, and degreasing of aircraft parts prior to plating.
A remedial investigation (RI) of the 3 Hangars site began in 1992. Samples were taken for metals, volatile
organic compounds (VOCs), semi-volatile organic compounds ( SVOCs), organochlorine pesticides, and
PCBs throughout the 3 Hangars area, and the adjacent drainage ditch located just east of Hwy 89. Elevated
levels of PCBs in the drainage ditch area led to additional sampling on the vacant lot west of Highway 89
and the wash areas behind the residences on El Vado Road. In February 1996, an investigation was
conducted on the residential properties which identified PCB concentrations ranging from less than 0.056
mg/kg to 6.2 mg/kg posing a health threat to residents, children, and transients. (USEPA, 1996). The wasterelated activities at the 3 Hangars site consisted of discharging waste fluids directly into floor drains, inside
Hangar 1 of the TIC site, which were then connected to the storm water drain pipe that discharged to the
adjacent Highway 89 drainage ditch. A culvert extended under Highway 89 from the drainage ditch allowing
the contaminants in the underlying soils in the drainage ditch to migrate into off-site residential properties.
See Figure 1 in Appendix.
In 1996, voluntary removal actions were conducted by the Tucson Airport Authority (TAA) on the 3 Hangars
site. These activities included the removal of PCB contaminated pipe sludge from the inlets to the drain
pipes in the Hangar area and plugging the floor drains and other inlets to the drain pipe systems to prevent
future surface water flows from entering the pipe systems and facilitating PCB migration. In March 1997,
the USEPA conducted soil remediation activities for the off-site residential areas. Contaminated soil on the
off-site residential properties and vacant lot was removed and replaced with clean fill dirt and new
landscaping. Replacement of the top soil with certified clean soil has removed all contact with the soil
containing PCBs eliminating any future public health threat.

1

B.
SITE VISIT
The El Vado residential site consists of a vacant lot, the backyards of 3 residences, the vacant area north and
west of the church all of which area located on the north side of El Vado Road. The residential properties
were built in the 1970's and 1980's.
A site visit was conducted by ADHS on January 7 and 20, 1999. Activities included visiting the 3 Hangars
site and the surrounding residential areas. The following observations were made:
2.

The 3 Hangars are currently leased to Tucson Industrial Centers, which sub-leases space to
industrial operations primarily aircraft-related firms. Buildings 25 and 24 which were located to the
west of the 3 Hangars site have been torn down but the foundations are still visible.

3.

The drainage outfall areas are located to the west of the 3 Hangars, next to the railroad tracks and
Highway 89. They are covered with desert vegetation such as grass, bushes, and small trees. A
culvert crosses under Highway 89 into a vacant lot on the west side of the railroad tracks.

4.

The off-site properties that were remediated include a vacant lot, the area behind 3 residences and
a church, and an additional vacant lot to the west of the church. Two of the three residential
properties are owned by one family. There are three houses located on these two properties. The
third residential property, which only has 1 house on it, is owned by a separate family. The
remediated areas have been appropriately landscaped and successfully molded into the surrounding
area.

5.

The residential backyards are covered primarily with dirt and gravel. There are horse stables, animal
stalls, a mobile home behind one residence, and parking areas.

6.

A church is located in the remediation area. A vacant lot which is probably used for parking is to
the west of the church and had an area where remediation occurred.

ADHS obtained information about the El Vado site from the Pima County Department of Environmental
Quality (PCDEQ), residents who live on El Vado, and from attending the community meeting on Wednesday,
January 20, 1999. Additional soil data was obtained from the TCE library located at the El Pueblo Clinic
on January 7, 1999. The TCE library collects data and information that is provided by various governmental
and community sources relating to the larger TIAA Superfund Site. This information is available to the
public.
C.
DEMOGRAPHICS, LAND USE, NATURAL RESOURCES
Demographics
The residential site is located on El Vado road directly west of the 3 Hangars site which is located in the
central western portion of the larger TIAA Superfund Site. El Vado Road extends westward from Highway
89 which runs north and south. There are two vacant lots on the northwest and southwest corners of El Vado
and Highway 89 and are covered primarily with dirt, gravel, and some grassy areas. Single family homes
are located on the north and south sides of El Vado Road to the west of the vacant lots and are landscaped
with typical desert plants and trees. The drainage ditch areas located to the east of 89 have typical native
desert brush and trees. (USEPA Memo, Sept. 10, 1996).
Land Use and Natural Resources Use
The major residential area of contamination is located on the north side of El Vado Road. This includes the

2

backyards of the Young, Alcoverde, and the Martinez residences, the vacant lot located on the northwest
corner to of El Vado Road and Highway 89, and the vacant areas north and west of the church. The
backyards of the residences are primarily covered with dirt and desert vegetation. There are open spaces,
horse stables, animal stalls, a mobile home, and parking areas throughout the remediated areas.
Water for the site is supplied by the City of Tucson municipal water system. The climate of Tucson, Arizona
is semi-arid with an average of between 10 and 11 inches of rainfall annually.(ADHS 1996a).
D.
HEALTH OUTCOME DATA
In 1996, ADHS conducted residential serum PCB blood tests for residents who live adjacent to the 3 Hangars
site. Results were as follows:
Residential Serum PCB Blood Tests
Upon finding elevated levels of PCBs in the residential area, ADHS was asked to conduct a health
consultation to determine the health implications of the possible PCB exposure to the residents. A total of
4 houses are located on the 3 residential properties. Three houses are owned and occupied by members of
the same family. The fourth house is owned and occupied by members of a separate family. In May 1996,
ADHS staff arranged to have blood tests conducted for serum PCB levels on 16 members of the two families
whose yards were found to have elevated levels of PCBs.
Interviews were conducted with the two families living on the properties, as well as the grown children whom
had lived on the property during the past 10 years and had children of their own while living on the site.
Several members of one family expressed concerns regarding symptoms experienced over the years that
could not be explained by their physicians. The symptoms ranged from severe acne to fainting spells. In
order to address their concerns, ADHS made arrangements to have interviews and blood tests for PCBs
conducted for the families. (ADHS, 1996b). ADHS made arrangements with the Pima County Health
Department to conduct the blood draw, and with Sonora Labs to perform the blood analysis. Twelve
members of the one family and 4 members of the second family were tested for PCBs in their blood. Results
of these blood tests are shown in Table 1.

Table 1: PCB Blood Levels in 16 Residents Living Adjacent to the 3 Hangars Site (1996)
Residents

PCB Levels in Microgram/Liter (µg/l)

3

Resident 1

Less than 3 µg/l

Resident 2

Less than 3 µg/l

Resident 3

Less than 3 µg/l

Resident 4

Less than 6 µg/l*

Resident 5

Less than 6 µg/l *

Resident 6

3.4 µg/l

Resident 7

Less than 3 µg/l

Resident 8

Less than 3 µg/l

Resident 9

Less than 3 µg/l

Resident 10

Less than 3 µg/l

Resident 11

Less than 3 µg/l

Resident 12

Less than 3 µg/l

Resident 13

Less than 3 µg/l

Resident 14

Less than 3 µg/l

Resident 15

Less than 3 µg/l

Resident 16

Less than 3 µg/l

#

Studies by the Centers for Disease Control and Prevention (CDC) demonstrate that most people without
occupational exposure have median blood PCB levels between 5 and 7 µg/l. Approximately 95% of these
values are below 20 µg/l. (ATSDR, 1999).

*

These two results were as accurate as the testing procedure and quality control criteria would allow on the
samples submitted.

COMMUNITY CONCERNS
During the site visit on January 7, 1999, ADHS staff had the opportunity to speak with members of one of
the families whose backyard had been remediated. They said that they were quite pleased with the outcome
of the remediation activities and has no complaints or further concerns. They also stated that their neighbors

4

who backyards were also remediated were very pleased with the results. They showed me around the
backyards and pointed out the areas that were remediated. The areas have blended into the natural
landscaping so there is no apparent area of differentiation. The areas are clean and have been well kept.
They were pleased that someone had followed up on the situation.
1.

How does EPA know that they found all the PCBs?

Sampling locations are determined by the geography, type of soil, and chemical that is being identified.
These properties allow EPA to choose the best sampling plan for a site. During the sampling of the yards,
PCBs were found to be concentrated in particular areas. The boundaries of these areas were determined when
PCBs did not show up in samples taken further away from these areas. Additional soil sampling all depended
upon how the PCB concentrations presented themselves. EPA has told all the families that if there is still
some concern about the presence of PCBs that might have gone undetected, they should call or write to the
EPA and express their concerns. Until now, no response has been received.
2.

Since the blood samples showed that the PCBs were not hurting anyone and didn’t present a
health threat, then why did EPA clean up the yards?

The decision to clean up the PCBs was not just to prevent any possible future exposures to the PCBs but also
to meet regulations and prevent further ecological damage. The previous ATSDR Health Consultation
conducted in 1997 stated that despite the presence of PCBs in the residential yards, nobody had elevated
levels of PCBs in their blood. This shows that even if people were getting exposed to the PCBs, it wasn’t
enough to show up in the blood. If the blood levels were high, this would indicate that people were being
or were exposed to the PCBs. EPA has a responsibility to make sure that any known contamination is below
certain standards, and also to address ecological concerns.

ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS
This Public Health Assessment evaluates if a public health hazard still exists to off-site residents since the
remediation activities were conducted in 1997. The discussion addresses the available data; the methodology
used in the identification process; the criteria for selection; and determination of the extent and levels of any
residual off-site contamination.
At the time this investigation was conducted, the Interim June,1995 Arizona Residential Health Based
Guidance Levels (HBGLs) were used as comparison values to determine if all the contaminated soil had been
removed. Remediation activities continued until all confirmatory samples were below 0.18 mg/kg. Since
then, the HBGLS were replaced by the Soil Remediation Levels (SRLs) which were promulgated in
November, 1997 and are currently used as comparison values. The HBGL for PCBs was more conservative
than the current SRL which indicates that all the confirmatory soil samples are below the respective SRL for
PCBs of 0.66 mg/kg.
Site-specific soil contaminant concentrations are compared to SRLs to determine which soil contaminants
will be evaluated further in the Health Assessment. SRLs for soil ingestion were calculated by the Arizona
Department of Health Services, Office of Environmental Health. SRLs are protective of human health,
including sensitive groups, over a lifetime. Chemical concentrations in soils that exceed SRLs may not
necessarily represent a health risk. Rather, when contaminant concentrations in soil exceed these standards,
further evaluation may be necessary to determine whether the site poses an unacceptable risk to human

5

health. (ADHS, 1997a).
The public health hazard from exposure to groundwater contamination is not analyzed in this public Health
Assessment as this exposure pathway was the focus of an USEPA Private Well Study conducted in1994.
(USEPA, 1994).
A.
ON-SITE CONTAMINATION
This Public Health Assessment does not evaluate the source contamination at the 3 Hangars site. This will
be reviewed in the final ATSDR Health Assessment for the complete TIAA site and for which a draft has
already been completed. (ATSDR, 1996).
B.
OFF-SITE CONTAMINATION
This section reviews the pre-remediation soil data and remediation confirmatory sample data to verify that
the remediation activities have eliminated any future health hazard.
Results from Pre-remediation Off-Site Investigations
In 1996, 82 shallow soil samples were collected at grid locations placed throughout the drainage areas, the
vacant lot, the backyards of four residential properties, and the area north and west of the church. The
results identified Aroclor 1260 and 1254 in 30 and 6 samples, respectively, in concentrations in excess of
the HBGLs for PCBs in soils of 0.18 mg/kg. In 1997, an additional 30 samples were taken. The results
identified Aroclor 1260 in 10 samples in concentrations in excess of the HBGL for PCBs.
As indicated in the final report of the remedial investigation, the overall pattern of the PCB distribution
consisted of a decreasing width of contaminated soils and decreasing concentrations as one moved to the
west from the 3 Hangars site. This pattern suggested that by the time surface water transporting or containing
the PCBs suspended soils reached the residential properties, most of the PCBs had been deposited in the soils
prior to the property lines. The areas of highest PCB soil concentrations were east of the residential areas.
(Daniel, July 2, 1996).
Post Remediation Soil Samples
Post remediation activities occurred during the period March to May, 1997. It consisted of the removal of
surface soils in the backyards of 4 residential properties, the vacant area north and west of the church, a
vacant lot all located west of Highway 89 between East El Vado and East Corona Roads, and the associated
drainages west of the 3 Hangars site. The remediation area was divided into five separate sections. These
five sections included:
!

Area A Drainage area east of Hwy.89;
Area B
Vacant lot west of Hwy. 89;
Area C
Backyard areas of the residences;
Area D1
Vacant area behind the church;
Area D2
Vacant area to the west of the church.
A total of 31 confirmatory soil samples were taken in these 5 areas during the remediation activities.
Remediation continued until samples indicated that the interim Arizona HBGL of 0.18 mg/kg PCBs had been
achieved. For this health assessment, the final confirmatory soil samples were compared to and were found
to be below the PCB Residential Arizona SRL of 0.66 mg/kg. Sample results are provided in Table 2 and
corresponding diagrams are provided in the Appendix. (Conestoga, 1997).

!
!
!
!

Table 2: Confirmatory Sample Results From Remediated Areas in El Vado Residential Area (1997)

6

Remediation Area

Number of
Samples

Range of PCB
Concentrations
(mg/kg)

Mean
(mg/kg)

SRL for
PCBs
(mg/kg)

Above
SRL

AREA A:
Drainage Area

12

0.643 - <0.033

0.32

0.66

NO

AREA B:
Vacant Lot

9

0.182 - <0.033

0.100

0.66

NO

AREA C:
Backyards of
Residences

5

0.122 - <0.033

0.076

0.66

NO

AREA D1:
Vacant Area North
of the Church

3

0.120 - 0.045

0.07

0.66

NO

AREA D2:
Vacant Area West of
the Church

2

0.039 - 0.035

0.037

0.66

NO

Results from Conestoga 1997

Groundwater Contamination
According to the USEPA, the leaching rate of PCBs downward through the soil and into the groundwater
does not pose a threat to human health and the environment. PCBs generally bind to surface soils and do not
leach to groundwater. PCBs have not been detected in the groundwater and have not been detected in soils
deeper than one (1) foot below ground surface at the Removal Site. Moreover, precipitation in the form of
rain, which facilitates the leaching process, averages about only 11 inches per year in the Tucson area.
Therefore, it can be assumed that PCB contamination at the Removal Site is not leaching toward the
groundwater table. (USEPA, 1996).
C.
QUALITY ASSURANCE AND QUALITY CONTROL
The Quality Assurance/Quality Control (QA/QC) summary appears to be of adequate quality for use in this
assessment. Sample concentration data, recording codes, reporting periods, monitor well identification, and
compound names were checked for consistency. Samples were analyzed by approved test methods. (ADHS
1996a). This health assessment uses qualified data from investigations conducted thus far to evaluate
health threats from potential exposure to contaminants in surface soils.

PATHWAY ANALYSES
To determine whether residents and transients are currently or could be exposed to any remaining soil
contaminants, ADHS evaluated the environmental and human components that lead to human exposure. This
pathway analysis consists of five elements:
!
!
!

A source of contamination;
Transport through an environmental medium;
A point of exposure;

7

!
!

A route of exposure; and
An exposed population.

This health assessment focuses on human populations living on El Vado Road. ADHS categorizes an
exposure pathway as a completed or potential exposure pathway if the exposure pathway cannot be
eliminated. Completed pathways require that the five elements exist and indicate that exposure to a
contaminant has occurred in the past, is currently occurring, or will occur in the future. Potential pathways,
however, require that at least one of the five elements is missing, but could exist. Potential pathways indicate
that exposure to a contaminant could have occurred in the past, could be occurring presently, or could occur
in the future. An exposure pathway can be eliminated if at least one of the five elements is missing and will
never be present.
Completed and potential exposure pathways and quality of the accompanying sampling data used to identify
the exposure scenarios are discussed below.
A.
COMPLETED EXPOSURE PATHWAYS
Past Exposure Pathways
The receptor populations and exposure pathways that were identified before the remediation activities
include the following:
Residential exposure to off-site contaminated surface soil

" Inhalation, Ingestion, Dermal
Before remediation occurred, dermal, ingestion, and inhalation exposures to contaminated soil were
identified for residents and transients. The backyards and vacant lot are areas where children play and
transient activity occurs. Children would have been exposed to the PCBs while playing in these areas via
incidental soil ingestion, inhalation of fugitive soil dust, and dermal exposures. There are small, poorly
worn trails through the brush in the vacant lot, indicating that some transient exposure may have occurred
and may still continue. Transients would have been exposed via inhalation and dermal exposures while
walking through the area. This does not appear to be an area where transients will sleep or temporarily
camp out. The past exposure pathways are summarized in Table 3 below.

Table 3: Complete Past Exposure Pathways at the El Vado Residential Site Before Remediation
Pathway
Name

EXPOSURE PATHWAY ELEMENTS
Source

Environmental
Media

Point of
Exposure

8

Route of
Exposure

Time
Exposed
Pop.

Surface
Soil

3 Hangars

Surface Soil

Residential
backyards,
drainage areas,
vacant lot

Ingestion
Inhalation
Dermal

Residents
Transients
Children

Past

It is estimated that approximately 30 people could be exposed to the post-remediated soil. This includes the
residential families, and persons who would visit the church for weekly services and activities.
B.
ELIMINATED EXPOSURE PATHWAYS
Current and Future Exposure Pathways
The contaminated soil in the backyards and vacant lot have been remediated but these areas continue to
be areas where children play and transient activity occurs. Children are exposed to the remediated soil
while playing via soil ingestion, inhalation of fugitive soil dust, and dermal exposures. Transients are
exposed to the remediated soil via inhalation and dermal exposures while walking through the area.

PUBLIC HEALTH IMPLICATIONS
A.
TOXICOLOGIC EVALUATION
This sections reviews the potential for adverse health effects in persons exposed to specific contaminants
through completed or potential exposure pathways. ADHS has analyzed the off-site exposure scenarios to
determine what, if any public health threat continues to exist from inhalation, dermal, and ingestion
exposures by residents and transients to the off-site remediated soil. A toxicological profile is located in the
Appendix.
If the PCB levels in the confirmatory samples are found to be above the respective SRL, exposure intakes
are then calculated and compared to the corresponding ATSDR Minimal Risk Levels (MRL). The MRL is
an estimate of daily human exposure to a contaminant below which non-cancer, adverse health effects are
unlikely to occur. MRLs are not used to determine the specific adverse health effects of exposure, rather they
are used to determine if there is the need for more thorough, contaminant specific investigation. MRLs are
not used to determine a safe level of contaminants at a site. MRLs are developed for each route of exposure,
such as inhalation and ingestion, and for a length of exposure, such as acute (less than 14 days), intermediate
(14 to 356 days), and chronic (greater than 365 days). Therefore, if exposures intakes are found to be above
their respective MRLs further evaluation is made to assess the health threats. (ATSDR, 1997).
The PCB soil concentrations in the confirmatory soil samples are well below the respective SRL. Therefore,
estimates of pathway specific exposure intake doses and exposure concentrations did not have to be
quantified for any specific on-site or off-site exposure pathways. As described previously in this assessment,
chemicals were eliminated as chemicals of concern (COCs) in these media if there were no positive
detections in the respective data set; or if the highest detected value was less than the corresponding Arizona
SRL. Since all site related contaminants met these criteria, it was not necessary to calculate exposure intakes
for further assessment. Therefore, current and future ingestion, inhalation, and dermal exposures to the
remediated soil at the current levels presented in this assessment, do not currently pose a public health hazard
to residents who live in the vicinity or children who play in the backyards where the soil was remediated.
B.
HEALTH OUTCOME DATA EVALUATION
In 1996, 16 residents were sampled for blood PCB levels by the ADHS. Thirteen residents had serum blood

9

levels below 3 µg/l, one resident had a level of 3.4 µg/l, and the remaining 2 residents had blood levels less
than 6 µg/l. According to population based studies conducted by the Centers for Disease Control and
Prevention (CDC), the average serum PCB levels in the U.S. range form 5 to 7 µg/l. (ATSDR, 1999).
Therefore we can conclude that the blood levels of PCBs detected are below the national average.
C.
ATSDR’S CHILD HEALTH INITIATIVE
The ADHS has prepared this public health assessment under a cooperative agreement with the Agency for
Toxic Substances and Disease Registry (ATSDR). ADHS has included the following information in
accordance with ATSDR’s Child Health Initiative.
Sub-populations of concern are sensitive receptor populations who may be particularly susceptible to
chemical exposure. They may include infants, the elderly, or individuals with respiratory problems
depending on the chemicals of concern and the nature of the exposures. The exposure points for sensitive
residents in this case include the backyards of the residences, the vacant areas north and to the west of the
church, and the vacant lot. Since the contamination has been remediated, future exposure to PCBs by
children who live and play in the area has been removed.
ATSDR’s Child Health Initiative recognizes that the unique vulnerabilities of infants and children demand
special emphasis in communities faced with contamination of their water, soil, air, or food. Children are at
greater risk than adults from certain kinds of exposures to hazardous substances emitted from waste sites and
emergency events. They are more likely to be exposed because they play outdoors and they often bring food
into contaminated areas. They are shorter than adults, which means they breathe dust, soil, and heavy vapors
close to the ground. Children are also smaller, resulting in higher doses of chemical exposure per body
weight. The developing body systems of children can sustain permanent damage if toxic exposures occur
during critical growth stages. SRLs are protective of human health, including sensitive groups, over a
lifetime. Residential SRLs are specifically protective of childhood exposure for systemic toxicity. Most
importantly, children depend completely on adults for risk identification and management decisions, housing
decisions, and access to medical care.

CONCLUSIONS
In summary, ADHS concludes that no current or future public health hazard exists as a result of ingestion,
dermal, or inhalation exposures by residents, children, or transients to the remeidated soil in the residential
areas on El Vado Road.
The confirmatory soil samples from the remeidated yards, vacant lot, and areas near the church did not
contain elevated levels of PCBs when compared to the respective SRLs. This indicates that the public
health hazard that had existed prior to the remediation has been eliminated. Therefore, current and future
residential exposures via inhalation, ingestion, or dermal exposures to the remediated soil does not pose a

10

health hazard.
Results of the health outcome data suggest that, despite the elevated levels of PCBs before the remediation
activities in the residential yards, no significant exposures had occurred. Since the PCB contamination in
the residential areas has now been removed, there is no future threat of exposure.
The residents whose yards were remediated are satisfied with the remediation results and have no further
concerns of exposures to the PCBs.

PUBLIC HEALTH ACTION PLAN
The Public Health Action Plan (PHAP)for the El Vado Residential Site contains a description of actions taken,
to be taken, or under consideration by ATSDR and ADHS at and near the site. The purpose of the PHAP is to
ensure that this public health assessment not only identifies public health hazards, but also provides a plan of
action designed to mitigate and prevent adverse human health effects resulting from exposure to hazardous
substances in the environment. ADHS and ATSDR will follow-up on this plan to ensure that actions are carried
out.
Actions Completed
1.

In May 1996, ADHS staff arranged to have blood tests conducted for serum PCB levels on 16
members of the two families whose yards were found to have elevated levels of PCBs.

2.

In July 1996, ADHS staff sent letters to the residents explaining test results.

3.

In 1996, the ADHS conducted a health consultation addressing the health concerns at the site.

4.

In March 1997, EPA remediated the residential yards at the El Vado Residential site.

5.

In January 1999, ADHS staff met with the El Vado residents on a one-to-one basis to discuss the health
assessment in order to address their concerns and questions. ADHS also attended a public meeting at
the Tucson UCAB (Unified Community Action Board) to speak with members about the health
assessment and their concerns.

6.

In February 1999, ADHS submitted a public health assessment for the El Vado Residential Site to the
ATSDR.

7.

In June 1999, ADHS staff sent out notices to area newspapers and radio stations to announce the public
comment period on the health assessment.

8.

In June 1999, ADHS staff was interviewed by Tucson radio station and newspaper on the El Vado Site
health assessment.

9.

In September 1999, ADHS staff attended the UCAB meeting in Tucson to answer any questions on the
El Vado Site. Staff also met with the residents at the El Vado site to discuss the results of the health
assessment and answer any questions.

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Actions Proposed
1.

ADHS will continue to meet with the community residents at the UCAB meetings on a regular basis
to communicate the ADHS activities being conducted at the Tucson site. Specific goals are to increase
the understanding of the technical aspects of the area contaminants and their fate and transport, and to
educate the community on ways to minimize their exposures to site-related contaminants and physical
hazards.

2.

ADHS will continue to work with EPA on any additional health concerns at the El Vado site.

RECOMMENDATIONS
This Public Health Assessment has determined that no current public health hazard exists to residents from
exposure to the post remediated soil. It can be assumed that whose backyards were remediated. Therefore,
the ADHS has no recommendation for further action on this site.

12

PREPARERS OF REPORT

Arizona Department of Health Services, Office of Environmental Health
Jan McCormick, Environmental Epidemiologist
Will Humble, Chief, Office of Environmental Health, Principal Investigator

ATSDR Regional Representative
William Nelson
Regional Services, Region IX
Office of the Assistant Administrator

ATSDR Technical Project Officer
Tammie McCray
Division of Health Assessment and Consultation
Superfund Site Assessment Branch

13

REFERENCES
1.

Agency for Toxic Substance and Disease Registry. Petitioned Public Health Assessment Update
to the 1988 Public Health Assessment. Tucson International Airport, Tucson, Az. May 20, 1996.

2.

Arizona Department of Health Services. Baseline Human Health Risk Assessment; Tucson
International Superfund Site. December 1, 1996a.

3.

Arizona Department of Health Services. Health Consultation for PCBs. 1996b.

4.

Arizona Department of Health Services. Arizona Soil Remediation Levels. January 30, 1997a.

5.

Arizona Department of Health Services. Deterministic Risk Assessment Guidance. May 5,
1997c.

6.

Conestoga-Rovers & Associates. PCB Removal Action Report. July 1997.

7.

Daniel B. Stephens & Associates, Inc. Memo: To Craig Cooper, USEPA. February 26, 1996.

8.

Daniel B. Stephens & Associates, Inc. Memo: To Craig Cooper, USEPA. April 26, 1996.

9.

Daniel B. Stephens & Associates, Inc. Memo: To Craig Cooper, USEPA. July 2, 1996.

10.

Daniel B. Stephens & Associates, Inc. “Summary of Limited Investigation Regarding the
Distribution of PCBs in Off Site Areas Tucson International Airport (TIA) Superfund Site”.
April 26, 1996.

11.

Pacific Toxicology Laboratories. Human Toxic Chemical Exposure. Vol. 1, Section B Issue 7.

12.

Pima County Department of Environmental Quality. Southside TCE Private Well Investigation
for the Tucson International Airport Area Superfund Site (TIAASS), Tucson, Arizona. November,
1994.

13.

.The Earth Technology Corporation. Valuation of Natural Background Metals Concentrations in
Arizona Soils. Tempe, Arizona. June, 1991.

14.

Sonora Labs. 3401 E. Harbour Drive, Phoenix, Az. 85034. 1996.

15.

U.S. Department of Health and Human Services, Agency for Toxic Substances and Disease
Registry. Toxicological Profile for PCBs. August 1999.

16.

U.S. Department of Health and Human Services, Agency for Toxic Substances and Disease
Registry. Petitioned Public Health Assessment Addendum, Tucson International Airport Area,
Tucson, Pima County, Arizona. November 5, 1996.

17.

U.S. Environmental Protection Agency. Southside TCE Private Well Investigation: Tucson
International Airport Area Superfund Site, Tucson Arizona. November, 1994.

14

18.

U.S. Environmental Protection Agency. Memo: From Craig Cooper to Keith Takata. Sept. 10,
1996.

15

APPENDIX
!

Figures for Confirmatory Soil Remediation Sample Concentrations

!

Toxicological Profile for PCBs

16

Toxicological Profile for PCBs
Dermal and ocular effects in the form of chloracne, skin rashes, and eye irritation have been observed
with occupational inhalation exposure to Aroclors. Chloracne is a distinctive acneform eruption manifested by
keratinous plugs called comedones and skin-colored cysts. Mild to moderate chloracne was seen in 7 of 14
workers exposed to 0.1 mg/m3 of Aroclors for an average period of 14.3 months. However, PCBs were not the
only substance to which workers were exposed. Workers receiving exposures at levels as low as 0.003 mg/m3
for >5 years had dermal effects which included rashes, pigmentation changes of the skin and nails, and other
skin changes. Eye irritations have also been documented with airborne PCB exposure. In these studies, workers
received exposure to various Aroclors at concentrations between 0 and 2.2 mg/m3 for >3 years.
Human health effects have been documented more frequently for inhalation exposure to PCBs than for
ingestion and dermal exposures. Respiratory symptoms have been reported for inhalation exposures to Aroclorexposed workers. Upper respiratory tract or eye irritation, cough, and tightness of the chest were documented
for 326 capacitor workers with inhalation exposure levels of 0.007-11 mg/m3. Limitations of the study included
the absence of a control group, poor definition of cohort, and other factors. Of 243 workers involved in the
above study, 14% demonstrated a decline in forced vital capacity (FVC) when compared to the standard values.
Of those with a decline in FVC, 80% manifested a restrictive pattern of impairment without radiologic changes.
There is limited evidence of neurological effects from inhalation exposure. In one study, almost half of the
workers at a capacitor plant receiving exposure to mean concentrations of Aroclors at 0.007-11 mg/m3 for 5
years complained of headache, dizziness, depression, fatigue, and nervousness. In addition, switchgear workers
exposed to Aroclor 1260 and 1242 at concentrations of 0.00001-0.012 mg/m3 had higher incidence of headaches
and problems with memory and sleeping compared to unexposed workers.
Neurological effects have been seen in humans but, particularly, in animals with oral exposure to PCB.
Farm families who ate dairy products and beef contaminated with PCBs had a 19% prevalence of numbness.
Because of the subjectivity of symptoms and the lack of controls, no definitive association could be shown
between PCB exposure and the neurological effect. In animals, doses between 0.8 and 3.2 mg/kg-day of
Aroclor 1016 in the diet for 20 weeks did not influence the concentrations of noradrenaline, adrenaline, or
serotonin in monkey brains. In addition, no histological changes were reported in the brains of rats administered
100 mg/kg-day of Aroclor 1242 by gavage every second day for three weeks. Changes in the neurotransmitter
serotonin were documented in several areas of the brain when rats received a mixture of Aroclor 1254 and 1260
at single, high doses of 500 and 1,000 mg/kg.
Animal studies have shown that PCBs containing 60% chlorine by weight are carcinogenic. At an
estimated dose of 5 mg/kg-day, Aroclor 1260, fed to female Sherman rats , resulted in the formation of
hepatocellular carcinomas. Sprague-Dawley rats formed liver tumors after receiving an estimated 3.45 mg/kgday of Aroclor 1260 in their diet for 24 months. In a National Cancer Institute study, no treatment-related liver
tumors manifested in Fisher-344 rats receiving estimated doses of 1.25, 2.5 or 5.0 mg/kg-day dietary Aroclor
1254 for 104-105 weeks. However, nonhepatic tumors (i.e. adenocarcinoma of the stomach, jejunum, or cecum)
were positively associated to the Aroclor 1254 treatment in male and female rats.
Cancer effects have been seen in workers exposed to PCBs by inhalation. The studies have had
limitations resulting in no definitive statement regarding PCBs cancer-causing effects. In one study, an excess
risk for cancers of the liver, biliary tract, or gall bladder was detected in 2,588 workers employed in two
capacitor factories. The workers had been employed between 1940 and 1976, at least three months, in areas with
the most exposure to PCBs. Aroclor 1254 was initially used, then Aroclor 1242 and finally Aroclor 1016.
Personal time-weighted average concentrations of Aroclor 1016 in 1977 were 0.024 to 0.393 mg/m3 at plant 1
and 0.170 to 1.26 mg/m3 at plant 2. There were three cases of liver, gall bladder, and/on biliary tract cancer as
compared to 1.07 expected, and four cases of rectal cancer as compared to an expected 1.19. One of the study’s
limitations was the small number of cases. In another study, increased mortality due to cancer was found in 544
male and 1, 556 female workers of a capacitor manufacturing plant in Italy. The workers had been employed

17

between 1946 and 1978 for at least one week. PCB mixtures containing 54% chlorine were in use until 1964
and eventually mixtures of 42% chlorine were in use until 1970. Area samples obtained in 1954 and 1977
revealed PCB air levels of 5.2 to 6.8 mg/m3 (54% chlorine) and 0.048 to 0.275 mg/m3 (42% chlorine). Among
the findings, deaths from all cancers in males were significantly greater than expected when contrasted to
national and local rates (14 observed versus 1.7 national and 2.2 local) and in females contrasted with local rates
(12 observed versus 5.3 expected). A significantly higher death rate from gastrointestinal tract cancer was seen
in males when contrasted to national and local rates. The study’s limitation involved the small number of cases,
short minimum exposure, and other factors. In addition, a mortality study of 3,643 workers of a capacitor
manufacturing facility revealed some indication of PCB exposure-related malignant melanoma. The mean
duration of employment was 4.1 years while the mean age at hire was 27 years. PCB had been utilized from
1957 -1977, and this was the period in which the workers had been employed. Aroclor 1242 was utilized until
1970 followed by Aroclor 1016. Area monitoring in 1977 detected mean concentrations of PCBs ranging from
16 to 76 µg/m3. The workers were also exposed to various other chemicals. A statistically significant difference
was seen for malignant melanoma when the observed cases (8) were contrasted to the expected number of cases
(2). The study had a number of limitations which included the small number of deaths, insufficient monitoring
data and other factors.

18