HEALTH CONSULTATION
CADET MANUFACTURING
VANCOUVER, CLARK COUNTY, WASHINGTON
BACKGROUND AND STATEMENT OF ISSUES
The Washington State Department of Health (DOH) prepared this health consultation at the request of the Washington State Department of Ecology (Ecology) to evaluate potential human health risks associated with the release of toxic chemicals at the Cadet Manufacturing Company (Cadet). DOH prepares health consultations under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR).
Cadet is located at 2500 W. Fourth Plain Boulevard in a mixed industrial, commercial, and residential area of Vancouver, Clark County, Washington (Appendix A, Figure 1).1 A residential area known as the Fruit Valley Neighborhood (FVN) borders Cadet to the east. To the south is Fourth Plain Boulevard, which is bordered on the south by the Port of Vancouver property. To the immediate north and west is a vacant L-shaped industrial parcel, and further to the north is more of the FVN followed by rural property (Figure 2). This site has been used for manufacturing electric home heaters since 1964. Part of that process included degreasing metal parts with chlorinated solvents followed by spray painting. Cadet discontinued the use of this cleaning process in 1976.
Swan Manufacturing (Swan) produced electric home heaters at the Cadet site from 1964 until
1972. Prior to 1964, Swan operated at another site, the former Port of Vancouver Building 2220,
located approximately a block south of Cadet (Figure 1). Both companies used vapor degreasing
pits and waterfall structures to collect over-spray. Cadet continued this practice until 1987.
Wastewater 
from the waterfall structures at the Cadet facility drained directly into the sanitary
sewer. Two breaks in the sewer beneath the east side of Cadet property were discovered and
repaired in the early and mid 1990s.1 No remediation has occurred at the Cadet site.2
In January 2000, Cadet and Ecology entered into a legal agreement (Agreed Order) that requires Cadet to investigate the nature and extent of chlorinated solvent contamination in soil and groundwater at the site.1 Chlorinated solvents consist of volatile organic compounds (VOCs) such as trichloroethylene (TCE) and tetrachloroethylene (PCE). Ecology has been concerned about VOCs moving from the Cadet facility to residential wells, public wells operated by the Port of Vancouver, and industrial wells operated by Great Western Malting where VOCs have been detected. The relationship between the Cadet groundwater contamination and the contamination discovered in the residential, public and industrial wells has not been established. However, it will be investigated by Ecology in the near future along with other nearby facilities where VOCs releases have occurred. Migration of VOCs from soil and groundwater into indoor air of residential homes and the Cadet facility is also an exposure pathway of concern.
Numerous samples of soil, drinking water, groundwater, indoor air, and soil gas at Cadet and surrounding areas have been analyzed for VOCs. TCE, PCE, and 1,1,1-trichloroethane (TCA) were consistently detected in soil gas in the vicinity of Cadet and the FVN, (area north of Fourth Plain Boulevard, south of 31st Street and west of W. Fruit Valley Road).3 The distribution patterns suggest that the source of VOC contamination in the soil vapor is the underlying contaminated groundwater.
Soil
The highest concentrations of TCE and PCE in soil on the Cadet property are 14 and 1.7 parts per million (ppm), respectively. These concentrations are below the most conservative ATSDR health comparison values of 60 ppm for TCE and 10 ppm for PCE. Health comparison values are compared with concentrations of contaminants in air, soil or water. Concentrations below health comparison values are not considered to be a health concern while those that exceed health comparison values are considered further in the discussion section.
Groundwater
The direction of groundwater flow in the area of the Cadet facility varies depending on the time of year and is influenced by the level of the Columbia River. Groundwater data collected since late 1999 indicates that the depth of the shallow groundwater table ranges from 11 to 37 feet below ground surface (bgs) in the vicinity of the Cadet facility. Groundwater fluctuates approximately 9 feet throughout the year. The lowest groundwater elevation is approximately 2.5 feet above mean sea level (msl); the highest elevation approximately 11.5 feet.4 Shallow groundwater levels and water quality data generally indicate an easterly groundwater flow direction from the Cadet facility.
Groundwater on the Cadet property and beneath the FVN is contaminated with TCE, PCE, TCA, cis-1,2-dichloroethene (cis-1,2-DCE), and 1,1-dichloroethene (1,1-DCE). The highest concentrations of these compounds were found near the Cadet facility (Table B1). The source of contamination is believed to be historic releases from the sewer lines at the Cadet facility. The highest groundwater concentrations of TCE and PCE were found beneath the east side of the Cadet building, near the sanitary sewer line (Figure 2). TCE and PCE were detected in June 2000 at 78,000 parts per billion (ppb) (station C-13) and in November 2000 at 70,000 ppb (station C-9), respectively.4,5
Although the relationship between the Cadet groundwater contamination and the residential, public, and industrial wells has not been established, DOH evaluated groundwater data obtained from these private wells to determine whether the detected contaminants pose a health threat.
Concentrations of VOCs in drinking water from the farm residence and rental house are provided in Table B2. The farm residence is located approximately 3,000 feet northwest of Cadet, and the rental house is located approximately 3,000 feet north-northwest of Cadet (Figure 1). The drinking water wells serving these homes were found to be contaminated with TCE and PCE at maximum concentrations of 4.37 and 1.13 ppb, respectively. Both of these residences will be connected to the City of Vancouver municipal water supply by December 2001.
Ecology and the Southwest Washington Health District (SWWHD) have been concerned with potential contamination of three Port of Vancouver drinking water wells located 4,420 feet south of Cadet on the east side of the Great Western Malting grain elevators. These wells do not serve residences but are used for drinking water at approximately 40 percent of the facilities in the Port of Vancouver industrial area. The use of these wells for drinking water will be phased out over the next two years and water services will be replaced with City of Vancouver municipal water. Quarterly sampling of the Port wells has shown one detection of TCE (6.7 ppb in March 1996) above the state drinking water standard of 5 ppb, known as the maximum contaminant level (MCL). TCE has not been detected in the Port wells since March 1998.
Great Western Malting uses four wells that draw up to 10 million gallons per day for processing barley from four different groundwater wells.2 These wells are not used for drinking water. Well #1 is no longer used. Wells 2 and 3, located on the south side of the plant are used for approximately 30 percent of the processing. A maximum concentration of 1.1 ppb TCE was found in wells 1 and 2, however, the TCE level is below the MCL. Wells 4 and 5 are located on the north side of the plant and have shown a maximum concentration of 35 ppb prior to March 2001. However, on March 16, 2001, air stripping towers were installed to remove TCE from wells 4 and 5. TCE has not been detected in these wells after air stripping treatment.
Indoor Air
VOCs in groundwater can migrate through the soil column and infiltrate into indoor air. Cadet conducted indoor air monitoring at its facility in March 2001. TCE, PCE, 1,4 dichlorobenzene, and m,p-xylene were detected (Table B3).
No indoor air monitoring has been conducted in the FVN. Cadet, however, collected soil gas samples from 3 to 4 feet below ground surface (bgs) in open areas within the FVN and its facility using a push probe technique to estimate VOCs. Analysis of soil gas showed elevated levels of VOCs at both Cadet and the FVN. Soil gas VOC levels measured at the Cadet facility were much higher (1,800,000 ug/m3 for TCE and 220,000 ug/m3 for PCE) than those in the FVN. Maximum PCE and TCE soil gas levels in the FVN were 3,200 and 4,300 ug/m3, respectively, with TCA as high as 2,000 ug/m3. All three FVN maximum detections were found at soil gas station FV-22 (Figure 2). The results of the soil gas sampling in the FVN, however, may underestimate chemical concentrations under buildings where contaminants tend to pool and concentrate.
DOH estimated levels of VOCs that might be present in indoor air in the FVN using the soil gas and groundwater data collected by Cadet and the revised Johnson and Ettinger (1991) model for subsurface vapor intrusion into buildings.6 The J&E models were designed to predict the incremental carcinogenic risk and non-carcinogenic hazard quotients associated with site specific soil gas and groundwater contaminant concentrations. The models, however, tend to underestimate the carcinogenic risks and non-carcinogenic hazard quotients associated with chlorinated solvents like those detected at the Cadet site.6
Two building scenarios are available in the model: buildings underlain by a basement or buildings underlain by a slab-on-grade. Because soil gas sampling results were only obtained from 3 to 4 feet below the ground surface in the FVN, only the slab-on-grade scenario was modeled. The slab-on-grade scenario was also used to predict the indoor air concentrations and associated health risks associated with the groundwater to indoor air pathway. Because of these limitations the carcinogenic risks and non-carcinogenic hazard quotients obtained during the modeling may be underestimated for buildings with basements.
Appendix D describes input parameters used during the modeling and the modeling results. VOC concentrations detected in soil gas and groundwater in the FVN are shown in Tables D1 and D3. The estimated potential indoor air risks associated with maximum VOC concentrations found in soil gas and groundwater in the FVN are given in Tables D2 and D4.
Although production wells at Great Western Malting are not used for drinking, a potential indoor air inhalation pathway was considered prior to March 2001, before the installation of air stripping towers. Passage of groundwater through the air-washing system, agitation and heating of this water used during steeping and germination, and heating of damp grain during kiln-drying could have released TCE in process water to indoor air.7 Despite low levels of TCE in process water, this pathway was considered because of the very large amounts of water used in processing. An average concentration of 10.2 and 10.5 ug/L TCE was detected in wells 4 and 5, respectively, during quarterly sampling between January 1998 and April 2000. Based on the amount of TCE entering the facility and available for off-gassing, a maximum concentration of 13.8 ug/m3 TCE was estimated in indoor air.7 This concentration does not exceed EPA's health comparison value of 40 ug/m3. This modeled concentration of TCE in indoor air was also evaluated for potential cancer risk of workers. The estimated cancer risk calculated for this exposure is not considered to be significant. Because wells 4 and 5 are now treated, potential health risk are even further reduced and, therefore, this pathway is not a health concern.
Environmental sampling data were screened using federal ATSDR and U.S. Environmental Protection Agency (EPA), health-based criteria (comparison values). Contaminant concentrations below comparison values are unlikely to pose a health threat, and were not further evaluated in this health consultation. Contaminant concentrations exceeding comparison values do not necessarily pose a health threat, but were further evaluated to determine whether they are at levels which could result in adverse human health effects.
There are two completed pathways of exposure associated with the Cadet site. They are inhalation of contaminated indoor air at the Cadet facility and inhalation of contaminated indoor air in FVN homes. There are two additional completed pathways from VOCs in private drinking water wells north of Cadet, and contaminated drinking water from Port of Vancouver wells, however, there does not appear to be evidence linking these targets to Cadet.
Volatile Organic Compounds in Private Drinking Water Wells
Each of the chemicals detected in private drinking water wells northwest of Cadet that exceeded their respective health comparison values were evaluated for both cancer and non-cancer health effects (Table B2). It is useful to note that the maximum levels of TCE and PCE found in these private wells do not exceed drinking water standards, known as maximum contaminant levels (MCLs), enforced for public water systems.
Exposure doses given below are based on the maximum concentrations detected and so represent a "worst case scenario." The ingested dose from drinking water was doubled in order to take into account skin absorption and inhalation of vapors resulting from showering, bathing and other indoor water uses. The assumption is that the combined dose from these two routes of exposure is equivalent to that of ingestion.9,10 It should be recognized that use of the maximum contaminant concentration may result in an over-estimation of actual exposure. Exposure dose calculations for contaminants exceeding comparison values are provided in Appendix C.
Non-cancer effects
In order to evaluate possible non-cancer effects from
exposure to contaminated drinking water, an exposure
dose was calculated and then compared to EPA's Oral
Reference Dose (RfD). An oral reference dose (RfD) is a
level of exposure to chemicals below which
non-cancerous effects are not expected. RfDs are based on
toxicity observed in animal or human studies involving
exposure to the chemical of concern. In order to account
for uncertainties in toxicity data and provide adequate
health protection, RfDs are set below toxic effect levels
with the use of "safety factors."
An estimated exposure dose that exceeds the RfD indicates only the potential for adverse health effects. The degree to which the RfD is exceeded by the exposure dose indicates how close it will be to the actual toxic effect level. If the estimated exposure dose is only slightly above the RfD, then that dose will fall well below the toxic effect level. The higher the estimated dose is above the RfD, the closer it will be to the toxic effect level.
The estimated doses for a child drinking 1 liter of water per day at the maximum concentrations of TCE (4.37 ppb) and PCE (1.13) are given in Appendix C, Table C1. The dose estimated for TCE is approximately two times higher than its proposed RfD while the dose estimated for PCE is well below its respective RfD. The RfD for TCE is based on liver, kidney and developmental toxicity observed in rats and mice. These effects are considered to be the most sensitive endpoints of TCE toxicity. Although the estimated dose for TCE is sightly higher than the proposed RfD, it is 2,000 times below the actual toxic effect level upon which the RfD is based and, therefore, is not expected to cause non-cancerous health effects.
Cancer effects
Recent and extensive review of available data has led EPA to characterize TCE as "highly likely to produce cancer in humans." EPA's former classification of PCE as a probable human carcinogen is currently under review; however, other health agencies consider PCE to be a probable human carcinogen. These classifications are based on sufficient evidence in animals and limited evidence in humans. However, the potential of TCE and PCE to cause cancer at the low-levels of exposure found at the Cadet site is not clear. The strongest evidence that TCE can cause cancer in humans comes from occupational studies that have found increases in lung, liver and kidney cancers in workers exposed over several years. The levels of exposure in these studies are generally much higher than those estimated for the Cadet site while exposure doses used in animal studies are thousands of times higher.
Although the data obtained from high-dose animal or worker exposure studies is not directly
applicable to exposures found at Cadet, theoretical cancer risk estimates can be made based on
this data. Such estimates are made with mathematical equations that use this high-dose data to
predict how many cancers might occur at lower doses. This process involves much uncertainty.
Current thinking suggests that there is no "safe dose" of a carcinogen and that a very small dose
of a carcinogen will give a very small cancer risk. Cancer risk estimates are, therefore, not yes/no
answers but measures of chance (probability). Such measures, however uncertain, are useful in
determining the magnitude of a cancer threat since any level of a carcinogenic contaminant
carries an associated risk. The validity of the "no safe dose" assumption for cancer-causing
chemicals is not clear. Some evidence suggests that
certain chemicals considered to be carcinogenic
must exceed a threshold of tolerance before
initiating cancer.
Cancer risk estimated from long-term exposure to the maximum levels of PCE and TCE found in drinking water near the Cadet site are given in Table C2. Since the source of VOCs has been present for more than 30 years, doses were calculated assuming a 30-year exposure of a child growing to adulthood averaged over a lifetime of 70 years. These estimates indicate only a very low risk for cancer.
Port of Vancouver Drinking Water Wells
The three Port of Vancouver drinking water wells are located approximately one mile south-southeast from the former Swan Manufacturing site, and 1.25 miles along the groundwater route (one-half mile east then 3/4 of a mile south). These wells provide drinking water service to approximately 40 percent of the Port industrial area. Maximum levels of TCE and PCE found in Port wells, to date, are 6.7 ppb (March 1996) and 0.7 ppb (March 1998), respectively. No contaminants have been detected since March 1998. The MCL for both TCE and PCE is 5 ppb.
Infrequent detections and the lack of significant
inhalation exposure (i.e., limited showering or
other household uses that release VOCs into
indoor air) indicate that exposures from Port
wells are probably lower than what is estimated
above for private wells.
Volatile Organic Compounds in Indoor Air at Cadet
The maximum indoor air concentrations of TCE, PCE, 1,4 dichlorobenzene, and m,p-xylene measured at the Cadet facility were all well below OSHA's permissible exposure limits (PEL) (Table B3). PEL's are enforceable regulatory limits on the amount or concentration of a substance in workplace air. However, workplace health comparison values are often several orders of magnitude higher than those set for the general public. The level of TCE measured in indoor air at Cadet (110 ug/m3) exceeds the inhalation reference concentration (RfC) of 40 µg/m3 set by EPA. The RfC is a contaminant level in air below which non-carcinogenic health effects are not expected. RfCs are set for the general public as opposed to the workplace. The measured level of TCE is also well-above what is considered to be a background level in indoor air. The very high concentrations of TCE and PCE found in groundwater beneath and near the Cadet facility indicate that TCE and PCE could be moving inside from groundwater (Table B1).
The RfC for TCE is based on critical effects in the central nervous system, liver, and endocrine
system.9 Since the RfC assumes a continuous exposure (24-hours a day, 7-days-per-week), it is
not appropriate for comparison with workplace exposures. Therefore, the RfC was adjusted to
175 µg/m3 to account for the fact that most
people work eight hours per day and five days
per week with two weeks vacation. Based on
the adjusted RfC, it is not likely that workers
at Cadet will experience adverse, non-carcinogenic health effects from inhalation of
TCE.
Cancer risks associated with exposure to TCE and PCE in workplace air are shown in Table C3. The levels of TCE and PCE measured in indoor air at Cadet indicates a low to moderate cancer risk. As noted previously, EPA is currently reviewing the carcinogenic potential of TCE and PCE. The cancer potency factors (also known slope factors) used to calculate risk are also under review and, therefore, the risk estimates provided here must be viewed with caution. Further, these estimates are based on a single sampling round that may not be representative of actual exposures.
Volatile Organic Compounds in Indoor Air in the Fruit Valley Neighborhood
Based on the vapor intrusion modeling, contaminated groundwater appears to pose a low health risk for the indoor air pathway in the FVN. Appendix D, Table 2 shows the incremental risk and hazard quotients from the maximum concentrations of five contaminants detected in soil vapor for three different types of soil (sand, loamy sand, and sandy loam). Appendix D, Table 4 shows the non-carcinogenic hazard quotient and the incremental carcinogenic risk from groundwater beneath FVN.6,8 The modeling results, however, may not accurately reflect actual conditions in FVN. As stated earlier, the soil gas samples were collected away from buildings where contaminants tend to pool and concentrate, only the slab-on-grade building scenario was evaluated, and the J&E model tends to underestimate the carcinogenic risk and non-carcinogenic hazard quotient associated with chlorinated solvents such as TCE and PCE. As a result, the risk may be underestimated.
Multiple Chemical Exposure
In almost every situation of environmental exposure, there are multiple contaminants to consider. The potential exists for these chemicals to interact in the body and increase or decrease the potential for adverse health effects. The vast number of chemicals in the environment make it impossible to measure all of the possible interactions between these chemicals. Individual cancer risk estimates can be added since they are measures of probability. When estimating non-cancer risk, however, similarities must exist between the chemicals if the doses are to be added. Groups of chemicals that have similar toxic effects can be added such as TCE, PCE, 1,4-dichlorobenzene and m,p-xylene, which cause liver toxicity. Although some chemicals can interact to cause a toxic effect that is greater than the added effect, there is little evidence demonstrating this at concentrations commonly found in the environment.
The combined exposures for residents and workers exposed to VOCs near the Cadet site is not expected to substantially increase the health risk that are evaluated above for each individual contaminant. The exposures estimated for TCE are the most significant of the contaminants found based on concentration and toxicity data.
EXPOSURE PATHWAYS AND CHILDREN
ATSDR's Child Health Initiative recognizes that the unique vulnerabilities of infants and children deserve special emphasis with regard to exposures to environmental contaminants. Infants, young children, and the unborn may be at greater risk than adults from exposure to particular contaminants. Exposure during key periods of growth and development may lead to malformation of organs (teratogenesis), disruption of function, and even premature death. In certain instances, maternal exposure, via the placenta, could adversely effect the unborn child.
After birth, children may receive greater exposures to environmental contaminants than adults. Children are often more likely to be exposed to contaminants from playing outdoors, ingesting food that has come into contact with hazardous substances, or breathing soil and dust. Pound for pound body weight, children drink more water, eat more food, and breathe more air than adults. For example, in the United States, children in the first 6 months of life drink 7 times as much water per pound as the average adult. The implication for environmental health is that, by virtue of children's lower body weight, given the same exposures, they can receive significantly higher relative contaminant doses than adults.
The exposures discussed above considered the increased exposure of young children compared to adults. Even under "worst-case" assumptions of exposure to the maximum levels of VOCs detected in drinking water, health risks for children are considered unlikely.
RECOMMENDATIONS/PUBLIC HEALTH ACTION PLAN
Steve Matthews
Office of Environmental Health Assessments
Washington State Department of Health
WDOH Designated Reviewer
Rob Duff
Program Manager
Office of Environmental Health Assessments
Washington State Department of Health
ATSDR Designated Reviewer
Debra Gable
Health assessment and Consultation
Agency for Toxic Substances and Disease Registry
Table B1. Volatile organic compounds in groundwater at the Cadet Manufacturing Company located in Vancouver, WA (ppb)
| Contaminant | Groundwater Concentration | Location of Sample (Figure 2) | Comparison Value | Cancer Class | Comparison Value Reference |
| TCE | 78,000 | C-13 | 3 | EPA-UR IARC-3 NTP-2 |
CREG |
| PCE | 70,000 | C-9 | 0.7 | EPA-UR IARC-2A NTP-2 |
|
| 1,1,1-TCA | 6,290 | DPW-1 | 200 | NTP-3 | MCL |
| cis-1,2-DCE | 1,600 | C-13 | 70 | ||
| 1,1-DCE | 10.8 | DPW-06 | 7 | EPA-C NTP-3 |
EPA-UR = Under review - U.S. Environmental Protection Agency
IARC-3 = Not classifiable - International Agency for Research on Cancer
NTP-2 = Reasonably anticipated to be a carcinogen - National Toxicology Program
- National Institute for Environmental Health Sciences
NTP-3 = Not classified
IARC-2A = Probably carcinogenic to humans (limited human evidence; sufficient
evidence in animals)
EPA-C = Possible human carcinogen (no human, limited animal studies)
Table B2. Volatile organic compounds in
residential drinking water northwest of the Cadet Manufacturing Company located
in Vancouver, WA (ppb)
| Contaminant | Sampling Date | Primary Residence (Farm) |
Rental House | Comparison Value | Cancer Class | Comparison Value Reference |
| TCE | September 1998 | ND | 3.99 | 3 | EPA-UR IARC-3 NTP-2 |
CREG |
| July 2001 | 0.51 | 4.37 | ||||
| PCE | September 1998 | ND | ND | 0.7 | EPA-UR IARC-2A NTP-2 |
|
| July 2001 | 1.13 | 0.65 |
ND = Not detected
EPA-UR = Under review - U.S. Environmental Protection Agency
IARC-3 = Not classifiable - International Agency for Research on Cancer
NTP-2 = Reasonably anticipated to be a carcinogen - National Toxicology Program
- National Institute for Environmental Health Sciences
IARC-2A = Probably carcinogenic to humans (limited human evidence; sufficient
evidence in animals)
Table B3. Indoor air sampling results at
the Cadet Manufacturing Company located in Vancouver, WA (ug/m3)
| Contaminant | Air Concentration | Permissible Exposure Limit (PEL) | Minimal Risk Level (MRL) | Reference Concentration (RfC) |
Cancer Class |
| TCE | 110 | 270,000 | 537 a | 40 b | EPA-UR IARC-3 NTP-2 |
| PCE | 35 | 678,000 | 271 | NA | EPA-UR IARC-2A NTP-2 |
| 1,4-dichlorobenzene | 98 | 450,000 | 601 | 800 | IARC-2B NTP-2 |
| m,p-xylene | 28 | 435,000 | 434 | NA | NTP-3 |
a: Based on exposure < 365 days
b: RfC needs to be corrected (raised) in order to account for the reduced exposure
duration and frequency of a worker versus residential scenario. The corrected
value given in the Discussion is 175 ug/m3 based on a 8 hours/day,
5 days/week, 50 weeks/year schedule.
NA: Not available
EPA-UR: Under review - U.S. Environmental Protection Agency
IARC-3: Not classifiable - International Agency for Research on Cancer
NTP-3: Not classified - National Toxicology Program - National Institute for
Environmental Health Sciences
IARC-2A: Probably carcinogenic to humans (limited human evidence; sufficient
evidence in animals)
NTP-2: Reasonably anticipated to be a carcinogen
EPA-C: Possible human carcinogen (no human, limited animal studies)
APPENDIX C: EXPOSURE DOSE CALCULATIONS
This section provides the calculated exposure doses and assumptions used for each completed exposure pathway. The dose estimates for each of these pathways are described in the discussion section of the document. Maximum concentrations are used to calculate these doses, representing a "worst-case" scenario that may overestimate actual exposure.
Dose estimates for residents living in the two homes north of Cadet exposed to TCE and PCE in drinking water include skin absorption and inhalation of vapors resulting from showering, bathing and other indoor water uses. The assumption is that the combined dose from these two routes of exposure is equivalent to that of ingestion. This assumption is supported by ATSDR guidance although some mathematical models indicate that the inhaled dose for VOCs volatilizing from drinking water can be several times higher than the ingested dose. The following exposure dose equation and exposure assumptions were used to calculate the doses given below in Tables C1 and C2.
Ingested Dose - Drinking Water
Inhaled Dose - Workers
Table C1. Non-cancer dose calculations for a child drinking water from residential wells near the Cadet Manufacturing Company in Vancouver, WA a
| Receptor Population | Exposure Route | Contaminant | Maximum Concentration (ppb) |
Estimated Dose (mg/kg-day) |
RfD (mg/kg/day) |
LOAEL (mg/kg/day) |
| Child (0-5years) |
Ingestion Inhalation Dermal |
TCE | 4.37 | 5E-4 | 3E-4 | 1.0 |
| PCE | 1.13 | 1E-4 | 1E-2 | 100 b |
a = The maximum ingested dose from drinking water was doubled
in order to take into account inhalation and dermal absorption from other sources
of exposure such as showering, dish washing, etc.
b = The RfD for PCE is actually based on a no-observed adverse effect level
(NOAEL) of 14 mg/kg/day.
Table C2. Cancer risk calculations for
drinking water exposure in residential wells near the Cadet Manufacturing Company
in Vancouver, WA a
| Receptor Population | Exposure Route | Contaminant | Maximum Concentration (ppb) |
Cancer Slope Factor
b (per mg/kg-day-) |
Cancer Risk |
| Child > Adult (30 yeas) |
Ingestion Inhalation Dermal |
TCE | 4.37 | 0.4 | 4E-5 |
| 0.02 | 2E-6 | ||||
| PCE | 1.13 | 0.052 | 1E-6 |
a = The maximum ingested dose from drinking water was doubled
in order to take into account inhalation and dermal absorption from other sources
of exposure such as showering, dish washing, etc.
b = TCE cancer risk calculations are made using either end of the suggested
range of cancer slope factors provided by EPA in their draft health assessment
for TCE. The lower of the two is based on an inhalation exposure of workers
while the higher is derived from a residential drinking water study.
Table C3. Cancer risk calculations for
indoor air exposure of workers at the Cadet Manufacturing Company in Vancouver,
WA
| Receptor Population | Exposure Route | Contaminant | Maximum Concentration (ug/m3) |
Cancer Slope Factor a (per mg/kg/day) |
Cancer Risk |
| Workers | Inhalation | TCE | 110 | 0.4 | 1E-3 |
| 0.02 | 7E-5 | ||||
| PCE | 35 | 0.002 | 2E-6 | ||
| 1,4-dichlorobenzene | 98 | NA | NA | ||
| m,p-xylene | 28 | NA | NA |
a = TCE cancer risk calculations are made using either end of the suggested range of cancer slope factors provided by EPA in their draft health assessment for TCE. The lower of the two is based on an inhalation exposure of workers while the higher is derived from a residential drinking water study.
APPENDIX D: JOHNSON & ETTINGER SOIL GAS AND GROUNDWATER SCREENING MODEL (FIRST TIER) SUMMARY FOR CADET MANUFACTURING
The J&E models were designed to evaluate whether buildings underlain by a basement (200 cm) or slab-on-grade (15 cm) would be affected by vapors migrating into indoor air from contaminated soil gas and groundwater. Because of limitations associated with the depth of the soil gas sampling (3-4 feet) in the FVN, only the slab-on-grade scenario was evaluated during the soil gas modeling. The same building scenario was used when modeling the groundwater to indoor air pathway. Because only limited modeling was conducted, the carcinogenic risks and non-carcinogenic hazard quotients obtained may be over or underestimated.
Soil Gas
Cadet collected and analyzed soil gas samples from three to four feet below ground surface (bgs) in the FVN to estimate chlorinated solvent concentrations. The soil gas samples were collected using a push probe technique. Table D1 summarizes the range of chemical concentrations detected in soil gas.
Table D1. Soil gas chemical concentrations in the Fruit Valley neighborhood near the Cadet Manufacturing Company located in Vancouver, WA (ug/m3)
| Chemical | CAS No. | Min. Conc. | Max. Conc. |
| 1,1-dichloroethene | 75354 | <1 | <200 |
| cis 1,2-dichloroethene | 156592 | <1 | <200 |
| 1,1,1-trichloroethane | 71556 | <2 | 2000 |
| trichloroethene | 79016 | <2 | 4300 |
| tetrachloroethene | 127184 | 16 | 3200 |
The J&E soil gas screening model was used to evaluate whether the maximum concentration of chlorinated solvent soil gas concentrations detected poses a health risk to people in the nearby FVN. The model predicts steady-state indoor air chemical concentrations and incremental risk and/or hazard quotients associated with the soil gas concentration data.
The model operates under the assumption that the soil column properties are homogeneous and isotropic. Since this rarely occurs in nature, the model was run using three different soil types (sand [S], loamy sand [LS], and sandy loam [SL]). These soil types were selected based on limited soil information available for the site. The groundwater temperature used for the modeling (12º C for western Washington) was extrapolated from average U.S. shallow groundwater temperature data provided in the J&E guidance document.
Default values were used for vadose zone soil properties - soil dry bulk density, soil total porosity, and soil water filled porosity. Default values were also used for averaging time for carcinogens, averaging time for non-carcinogens, exposure duration, and exposure frequency when calculating the incremental risks. The unit risk factor (URF) or reference concentration (RfC) provided in the J&E model for 1,1 dichloroethene, cis 1,2-dichloroethene, tetrachloroethene, and 1,1,1-trichloroethane were used during the modeling. A URF was calculated for TCE based on the proposed U.S. EPA cancer slope factor of 0.02 kg-day/mg. This slope factor is based on a worker inhalation exposure.
Table D2 summarizes the potential indoor air risk results associated with the maximum concentration of each chemical in the soil gas. The incremental risks associated with the modeled indoor air concentrations of individual chemicals from soil gas ranged from 2.4E-08 to 8.1E-07. The hazard quotients ranged from 4.2E-04 to 6.3E-05.
Table D2. Indoor air cancer risks and hazard quotients estimated from soil gas levels for the Fruit Valley neighborhood located near the Cadet Manufacturing, Vancouver, WA
| Chemical | Concentration (ug/m3) |
Vadose Zone |
Cancer Risk | HazardQuotient |
| 1,1-dichloroethylene | 200 | S | 3.60E-07 | NA |
| LS | 2.30E-07 | |||
| SL | 1.40E-07 | |||
| cis 1,2-dichloroethene | 200 | S | NA | 4.20E-04 |
| LS | 2.80E-04 | |||
| SL | 1.80E-04 | |||
| 1,1,1-trichloroethane | 2000 | S | NA | 1.50E-04 |
| LS | 1.00E-04 | |||
| SL | 6.30E-05 | |||
| trichloroethylene | 4300 | S | 8.10E-07 | NA |
| LS | 5.40E-07 | |||
| SL | 3.30E-07 | |||
| tetrachloroethylene | 3200 | S | 5.70E-08 | NA |
| LS | 3.90E-08 | |||
| SL | 2.40E-08 |
* S = Sand; LS = Loamy Sand; SL = Sandy Loam
Groundwater
The J&E groundwater screening model was also run to evaluate the groundwater to indoor air pathway using the slab-on-grade building scenario. Groundwater data obtained from the August 2001 sampling round was used to predict the incremental risk and/or hazard quotient associated with the same chlorinated solvents evaluated during the soil gas modeling. The maximum groundwater concentration of each of the five chemicals that were detected during the soil gas monitoring was selected for the modeling. Table D3 summarizes the groundwater data used during the modeling.
Table D3. Groundwater chemical concentrations in the Fruit Valley neighborhood near Cadet Manufacturing located in Vancouver, WA (ppb)
| Chemical | CAS No. | Monitoring Well No. | Max. Conc. |
| 1, 1 - dichloroethene | 75354 | MW-03S | 5.3 |
| cis 1, 2 - dichloroethene | 156592 | MW-06S | 8.55 |
| 1, 1, 1 - trichloroethane | 71556 | MW-06S | 49.2 |
| trichloroethylene | 79016 | MW-05S | 1420 |
| tetrachloroethylene | 127184 | MW-05S | 169 |
Based on information provided by Cadet, shallow groundwater depth in the vicinity of the site varies seasonally with precipitation. Groundwater depth is shallowest in the spring, approximately 8 feet bgs. The deepest groundwater depths occur in the fall, approximately 21 feet bgs. The groundwater-screening model was run using both depths. For modeling purposes, it was assumed that the August 2001 results represented groundwater concentrations that would be detected throughout the year. Consistent with the soil gas modeling, an estimated groundwater temperature of 12ºC was used.
The groundwater screening model, like the soil gas model, was run using three different soil types (sand [S], loamy sand [LS], and sandy loam [SL]). Default values were used for vadose zone soil properties - soil dry bulk density, soil total porosity, and soil water filled porosity. Default values were also used for averaging time for carcinogens, averaging time for non-carcinogens, exposure duration, and exposure frequency when calculating the incremental risks. The unit risk factor (URF) or reference concentration (RfC) provided in the J&E model for 1,1 dichloroethene, cis 1,2-dichloroethene, tetrachloroethene, and 1,1,1-trichloroethane were used during the modeling. A URF was calculated for TCE based on the proposed U.S. EPA cancer slope factor of 0.02 kg-day/mg. This slope factor is based on a worker inhalation exposure.
Table D4 summarizes the potential indoor air risk results associated with the maximum concentration of each chemical in the shallow groundwater associated with the slab-on-grade building scenario. The incremental risks associated with the modeled indoor air concentrations of individual chemicals from groundwater ranged from 2.5E-05 to 1.4E-07. The hazard quotients ranged from 7.0E-04 to 1.8E-04.
Table D4. Indoor air cancer risks and hazard quotients estimated from groundwater levels for the Fruit Valley neighborhood located near Cadet Manufacturing, Vancouver, WA
| Chemical | GW Conc (ug/l) | SCS Soil Type* | GW Depth (ft(cm) bgs) |
Indoor Air | ||
| Above Water Table | Vadose Zone | Cancer Risk | Hazard Quotient (Non Cancer) |
|||
| 1,1 - dichloroethene | 5.3 | S | S | 8(244) | 2.7E-06 | NA |
| S | S | 21(640) | 1.0E-06 | |||
| LS | LS | 8(244) | 2.1E-06 | |||
| LS | LS | 21(640) | 9.4E-07 | |||
| SL | SL | 8(244) | 1.5E-06 | |||
| SL | SL | 21(640) | 8.0E-07 | |||
| cis 1,2 - dichloroethene | 8.55 | S | S | 8(244) | NA | 7.00E-04 |
| S | S | 21(640) | 2.70E-04 | |||
| LS | LS | 8(244) | 5.60E-04 | |||
| LS | LS | 21(640) | 2.40E-04 | |||
| SL | SL | 8(244) | 4.20E-04 | |||
| SL | SL | 21(640) | 2.10E-04 | |||
| 1,1,1 - trichloroethane | 49.2 | S | S | 8(244) | NA | 6.10E-04 |
| S | S | 21(640) | 2.30E-04 | |||
| LS | LS | 8(244) | 4.90E-04 | |||
| LS | LS | 21(640) | 2.10E-04 | |||
| SL | SL | 8(244) | 3.60E-04 | |||
| SL | SL | 21(640) | 1.80E-04 | |||
| trichloroethylene | 1420 | S | S | 8(244) | 2.5E-05 | NA |
| S | S | 21(640) | 9.4E-06 | |||
| LS | LS | 8(244) | 2.0E-05 | |||
| LS | LS | 21(640) | 8.6E-06 | |||
| SL | SL | 8(244) | 1.5E-05 | |||
| SL | SL | 21(640) | 7.4E-06 | |||
| tetrachloroethylene | 169 | S | S | 8(244) | 4.6E-07 | NA |
| S | S | 21(640) | 1.7E-07 | |||
| LS | LS | 8(244) | 3.7E-07 | |||
| LS | LS | 21(640) | 1.6E-07 | |||
| SL | SL | 8(244) | 2.8E-07 | |||
| SL | SL | 21(640) | 1.4E-07 | |||
* S = Sand; LS = Loamy Sand; SL = Sandy Loam
This Health Consultation was prepared by the Washington State Department of Health 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 consultation was begun.
Debra Gable
Technical Project Officer
SPS, SSAB, DHAC
ATSDR
The Division of Health Assessment and Consultation, ATSDR, has reviewed this public health consultation and concurs with the findings.
Richard Gillig
Branch Chief
SSAB, DHAC
ATSDR
