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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 therequest of the Washington State Department of Ecology (Ecology) to evaluate potential humanhealth 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 forToxic Substances and Disease Registry (ATSDR).

Cadet is located at 2500 W. Fourth Plain Boulevard in a mixed industrial, commercial, andresidential area of Vancouver, Clark County, Washington (Appendix A, Figure 1).1 A residentialarea known as the Fruit Valley Neighborhood (FVN) borders Cadet to the east. To the south isFourth Plain Boulevard, which is bordered on the south by the Port of Vancouver property. Tothe immediate north and west is a vacant L-shaped industrial parcel, and further to the north ismore of the FVN followed by rural property (Figure 2). This site has been used formanufacturing electric home heaters since 1964. Part of that process included degreasing metalparts with chlorinated solvents followed by spray painting. Cadet discontinued the use of thiscleaning process in 1976.

Swan Manufacturing (Swan) produced electric home heaters at the Cadet site from 1964 until1972. 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 degreasingpits 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 sanitarysewer. Two breaks in the sewer beneath the east side of Cadet property were discovered andrepaired 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 requiresCadet to investigate the nature and extent of chlorinated solvent contamination in soil andgroundwater at the site.1 Chlorinated solvents consist of volatile organic compounds (VOCs) such as trichloroethylene (TCE) and tetrachloroethylene (PCE). Ecology has been concernedabout VOCs moving from the Cadet facility to residential wells, public wells operated by thePort of Vancouver, and industrial wells operated by Great Western Malting where VOCs havebeen detected. The relationship between the Cadet groundwater contamination and thecontamination 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 facilitieswhere VOCs releases have occurred. Migration of VOCs from soil and groundwater into indoorair 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 andsurrounding 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 FourthPlain Boulevard, south of 31st Street and west of W. Fruit Valley Road).3 The distributionpatterns suggest that the source of VOC contamination in the soil vapor is the underlyingcontaminated groundwater.

Soil

The highest concentrations of TCE and PCE in soil on the Cadet property are 14 and 1.7 partsper million (ppm), respectively. These concentrations are below the most conservative ATSDRhealth comparison values of 60 ppm for TCE and 10 ppm for PCE. Health comparison values arecompared with concentrations of contaminants in air, soil or water. Concentrations below healthcomparison values are not considered to be a health concern while those that exceed healthcomparison 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 timeof year and is influenced by the level of the Columbia River. Groundwater data collected sincelate 1999 indicates that the depth of the shallow groundwater table ranges from 11 to 37 feetbelow ground surface (bgs) in the vicinity of the Cadet facility. Groundwater fluctuatesapproximately 9 feet throughout the year. The lowest groundwater elevation is approximately 2.5feet above mean sea level (msl); the highest elevation approximately 11.5 feet.4 Shallowgroundwater levels and water quality data generally indicate an easterly groundwater flowdirection 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 highestconcentrations of these compounds were found near the Cadet facility (Table B1). The source ofcontamination is believed to be historic releases from the sewer lines at the Cadet facility. Thehighest groundwater concentrations of TCE and PCE were found beneath the east side of theCadet building, near the sanitary sewer line (Figure 2). TCE and PCE were detected in June 2000at 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 obtainedfrom 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 areprovided in Table B2. The farm residence is located approximately 3,000 feet northwest ofCadet, and the rental house is located approximately 3,000 feet north-northwest of Cadet (Figure1). The drinking water wells serving these homes were found to be contaminated with TCE andPCE at maximum concentrations of 4.37 and 1.13 ppb, respectively. Both of these residenceswill be connected to the City of Vancouver municipal water supply by December 2001.

Ecology and the Southwest Washington Health District (SWWHD) have been concerned withpotential contamination of three Port of Vancouver drinking water wells located 4,420 feet southof Cadet on the east side of the Great Western Malting grain elevators. These wells do not serveresidences but are used for drinking water at approximately 40 percent of the facilities in the Portof Vancouver industrial area. The use of these wells for drinking water will be phased out overthe 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 processingbarley 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 forapproximately 30 percent of the processing. A maximum concentration of 1.1 ppb TCE wasfound in wells 1 and 2, however, the TCE level is below the MCL. Wells 4 and 5 are located onthe north side of the plant and have shown a maximum concentration of 35 ppb prior to March2001. However, on March 16, 2001, air stripping towers were installed to remove TCE fromwells 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. Cadetconducted 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 gassamples from 3 to 4 feet below ground surface (bgs) in open areas within the FVN and its facilityusing a push probe technique to estimate VOCs. Analysis of soil gas showed elevated levels ofVOCs at both Cadet and the FVN. Soil gas VOC levels measured at the Cadet facility weremuch 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 gasstation FV-22 (Figure 2). The results of the soil gas sampling in the FVN, however, mayunderestimate chemical concentrations under buildings where contaminants tend to pool andconcentrate.

DOH estimated levels of VOCs that might be present in indoor air in the FVN using the soil gasand groundwater data collected by Cadet and the revised Johnson and Ettinger (1991) model forsubsurface vapor intrusion into buildings.6 The J&E models were designed to predict theincremental carcinogenic risk and non-carcinogenic hazard quotients associated with sitespecific soil gas and groundwater contaminant concentrations. The models, however, tend tounderestimate the carcinogenic risks and non-carcinogenic hazard quotients associated withchlorinated solvents like those detected at the Cadet site.6

Two building scenarios are available in the model: buildings underlain by a basement orbuildings underlain by a slab-on-grade. Because soil gas sampling results were only obtainedfrom 3 to 4 feet below the ground surface in the FVN, only the slab-on-grade scenario wasmodeled. The slab-on-grade scenario was also used to predict the indoor air concentrations andassociated health risks associated with the groundwater to indoor air pathway. Because of theselimitations the carcinogenic risks and non-carcinogenic hazard quotients obtained during themodeling may be underestimated for buildings with basements.

Appendix D describes input parameters used during the modeling and the modeling results. VOCconcentrations 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 insoil 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 indoorair inhalation pathway was considered prior to March 2001, before the installation of airstripping towers. Passage of groundwater through the air-washing system, agitation and heatingof this water used during steeping and germination, and heating of damp grain during kiln-dryingcould have released TCE in process water to indoor air.7 Despite low levels of TCE in processwater, this pathway was considered because of the very large amounts of water used inprocessing. 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 theamount of TCE entering the facility and available for off-gassing, a maximum concentration of13.8 ug/m3 TCE was estimated in indoor air.7 This concentration does not exceed EPA's healthcomparison value of 40 ug/m3. This modeled concentration of TCE in indoor air was alsoevaluated for potential cancer risk of workers. The estimated cancer risk calculated for thisexposure is not considered to be significant. Because wells 4 and 5 are now treated, potentialhealth risk are even further reduced and, therefore, this pathway is not a health concern.


DISCUSSION

Environmental sampling data were screened using federal ATSDR and U.S. EnvironmentalProtection Agency (EPA), health-based criteria (comparison values). Contaminantconcentrations below comparison values are unlikely to pose a health threat, and were not furtherevaluated in this health consultation. Contaminant concentrations exceeding comparison valuesdo not necessarily pose a health threat, but were further evaluated to determine whether they areat levels which could result in adverse human health effects.

There are two completed pathways of exposure associated with the Cadet site. They areinhalation of contaminated indoor air at the Cadet facility and inhalation of contaminated indoorair in FVN homes. There are two additional completed pathways from VOCs in private drinkingwater 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 exceededtheir respective health comparison values were evaluated for both cancer and non-cancer healtheffects (Table B2). It is useful to note that the maximum levels of TCE and PCE found in theseprivate 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 representa "worst case scenario." The ingested dose from drinking water was doubled in order to take intoaccount skin absorption and inhalation of vapors resulting from showering, bathing and otherindoor water uses. The assumption is that the combined dose from these two routes of exposureis equivalent to that of ingestion.9,10 It should be recognized that use of the maximumcontaminant concentration may result in an over-estimation of actual exposure. Exposure dosecalculations for contaminants exceeding comparison values are provided in Appendix C.

Non-cancer effects

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 set by the Environmental Protection Agency (EPA).In order to evaluate possible non-cancer effects fromexposure to contaminated drinking water, an exposuredose was calculated and then compared to EPA's OralReference Dose (RfD). An oral reference dose (RfD) is alevel of exposure to chemicals below whichnon-cancerous effects are not expected. RfDs are based ontoxicity observed in animal or human studies involvingexposure to the chemical of concern. In order to accountfor uncertainties in toxicity data and provide adequatehealth protection, RfDs are set below toxic effect levelswith the use of "safety factors."

An estimated exposure dose that exceeds the RfD indicates only the potential for adverse healtheffects. The degree to which the RfD is exceeded by the exposure dose indicates how close itwill be to the actual toxic effect level. If the estimated exposure dose is only slightly above theRfD, then that dose will fall well below the toxic effect level. The higher the estimated dose isabove 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 concentrationsof TCE (4.37 ppb) and PCE (1.13) are given in Appendix C, Table C1. The dose estimated forTCE is approximately two times higher than its proposed RfD while the dose estimated for PCEis well below its respective RfD. The RfD for TCE is based on liver, kidney and developmentaltoxicity observed in rats and mice. These effects are considered to be the most sensitiveendpoints of TCE toxicity. Although the estimated dose for TCE is sightly higher than theproposed RfD, it is 2,000 times below the actual toxic effect level upon which the RfD is basedand, 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 likelyto produce cancer in humans." EPA's former classification of PCE as a probable humancarcinogen is currently under review; however, other health agencies consider PCE to be aprobable human carcinogen. These classifications are based on sufficient evidence in animalsand limited evidence in humans. However, the potential of TCE and PCE to cause cancer at thelow-levels of exposure found at the Cadet site is not clear. The strongest evidence that TCE cancause cancer in humans comes from occupational studies that have found increases in lung, liverand kidney cancers in workers exposed over several years. The levels of exposure in thesestudies are generally much higher than those estimated for the Cadet site while exposure dosesused in animal studies are thousands of times higher.

Cancer Risk -- Cancer risk estimates do not reach zero no matter how low the level of exposure to a carcinogen. Terms used to describe this risk are defined below as the number of excess cancers expected in a lifetime: moderate is approximately equal to 1 in 1,000 - low is approximately equal to 1 in 10,000 - very low is approximately equal to 1 in 100,000 - slight is approximately equal to 1 in 1,000,000 - insignificant is less than 1 in 1,000,000Although the data obtained from high-dose animal or worker exposure studies is not directlyapplicable to exposures found at Cadet, theoretical cancer risk estimates can be made based onthis data. Such estimates are made with mathematical equations that use this high-dose data topredict 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 doseof a carcinogen will give a very small cancer risk. Cancer risk estimates are, therefore, not yes/noanswers but measures of chance (probability). Such measures, however uncertain, are useful indetermining the magnitude of a cancer threat since any level of a carcinogenic contaminantcarries an associated risk. The validity of the "no safe dose" assumption for cancer-causingchemicals is not clear. Some evidence suggests thatcertain chemicals considered to be carcinogenicmust exceed a threshold of tolerance beforeinitiating cancer.

Cancer risk estimated from long-term exposure tothe maximum levels of PCE and TCE found indrinking water near the Cadet site are given inTable C2. Since the source of VOCs has beenpresent for more than 30 years, doses werecalculated assuming a 30-year exposure of a childgrowing to adulthood averaged over a lifetime of70 years. These estimates indicate only a very lowrisk 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 toapproximately 40 percent of the Port industrial area. Maximum levels of TCE and PCE foundin Port wells, to date, are 6.7 ppb (March 1996) and 0.7 ppb (March 1998), respectively. Nocontaminants have been detected since March 1998. The MCL for both TCE and PCE is 5 ppb.

Maximum Contaminant Level (MCL) -- The MCL is a regulatory limit set by the Environmental Protection Agency (EPA) for contaminants in public drinking water. If an MCL is exceeded, regulatory action is required under the Safe Drinking Water Act. MCLs are not always strictly health based but can consider technological or economic feasibility. The Washington State Department of Health (DOH) regulates public drinking water supplies in Washington State.Infrequent detections and the lack of significantinhalation exposure (i.e., limited showering orother household uses that release VOCs intoindoor air) indicate that exposures from Portwells are probably lower than what is estimatedabove 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-xylenemeasured at the Cadet facility were all well belowOSHA's permissible exposure limits (PEL)(Table B3). PEL's are enforceable regulatory limits on the amount or concentration of asubstance in workplace air. However, workplace health comparison values are often severalorders of magnitude higher than those set for the general public. The level of TCE measured inindoor air at Cadet (110 ug/m3) exceeds the inhalation reference concentration (RfC) of 40 g/m3set by EPA. The RfC is a contaminant level in air below which non-carcinogenic health effectsare not expected. RfCs are set for the general public as opposed to the workplace. The measuredlevel of TCE is also well-above what is considered to be a background level in indoor air. Thevery high concentrations of TCE and PCE found in groundwater beneath and near the Cadetfacility indicate that TCE and PCE could be moving inside from groundwater (Table B1).

Background -- Background is defined here as the amount of TCE expected to be present in air without any known contribution from a particular source. Since VOCs are expected to be present in urban indoor and outdoor air, it is useful to estimate what the expected level is in order to determine whether levels are higher due to an identified source.The RfC for TCE is based on critical effects in the central nervous system, liver, and endocrinesystem.9 Since the RfC assumes a continuous exposure (24-hours a day, 7-days-per-week), it isnot appropriate for comparison with workplace exposures. Therefore, the RfC was adjusted to175 g/m3 to account for the fact that mostpeople work eight hours per day and five daysper week with two weeks vacation. Based onthe adjusted RfC, it is not likely that workersat Cadet will experience adverse, non-carcinogenic health effects from inhalation ofTCE.

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 healthrisk for the indoor air pathway in the FVN. Appendix D, Table 2 shows the incremental risk andhazard quotients from the maximum concentrations of five contaminants detected in soil vaporfor three different types of soil (sand, loamy sand, and sandy loam). Appendix D, Table 4 showsthe non-carcinogenic hazard quotient and the incremental carcinogenic risk from groundwaterbeneath FVN.6,8 The modeling results, however, may not accurately reflect actual conditions inFVN. As stated earlier, the soil gas samples were collected away from buildings wherecontaminants tend to pool and concentrate, only the slab-on-grade building scenario wasevaluated, and the J&E model tends to underestimate the carcinogenic risk and non-carcinogenichazard 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 thepotential for adverse health effects. The vast number of chemicals in the environment make itimpossible to measure all of the possible interactions between these chemicals. Individual cancerrisk estimates can be added since they are measures of probability. When estimating non-cancerrisk, however, similarities must exist between the chemicals if the doses are to be added. Groupsof chemicals that have similar toxic effects can be added such as TCE, PCE, 1,4-dichlorobenzeneand m,p-xylene, which cause liver toxicity. Although some chemicals can interact to cause atoxic effect that is greater than the added effect, there is little evidence demonstrating this atconcentrations commonly found in the environment.

The combined exposures for residents and workers exposed to VOCs near the Cadet site is notexpected to substantially increase the health risk that are evaluated above for each individualcontaminant. The exposures estimated for TCE are the most significant of the contaminantsfound based on concentration and toxicity data.


EXPOSURE PATHWAYS AND CHILDREN

ATSDR's Child Health Initiative recognizes that the unique vulnerabilities of infants andchildren 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 toparticular contaminants. Exposure during key periods of growth and development may lead to malformation of organs (teratogenesis), disruption of function, and even premature death. Incertain 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, ingestingfood that has come into contact with hazardous substances, or breathing soil and dust. Pound forpound 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 muchwater per pound as the average adult. The implication for environmental health is that, by virtueof children's lower body weight, given the same exposures, they can receive significantly higherrelative contaminant doses than adults.

The exposures discussed above considered the increased exposure of young children comparedto adults. Even under "worst-case" assumptions of exposure to the maximum levels of VOCsdetected in drinking water, health risks for children are considered unlikely.


CONCLUSIONS

  1. Computer modeling predicts only a low potential health risk from volatile organiccompounds (VOCs) migrating into indoor air from groundwater. However, the risks maybe underestimated because of data and model limitations. Therefore, potential exposureto VOCs in indoor air in FVN homes represents an indeterminate public health hazard.

  2. No apparent public health hazard exists from exposure to maximum concentrations ofTCE and PCE in drinking water in the two private wells north of Cadet. Levels of TCEand PCE in these wells are not likely to result in any adverse health effects. However,this exposure would be of concern should levels of TCE or PCE increase. Exposure toTCE and PCE should be eliminated when these two residences are connected to themunicipal water supply.

  3. No apparent public health hazard exists from exposure to maximum concentrations ofTCE and PCE in drinking water from the three Port of Vancouver wells located south ofCadet. Detections have been infrequent in the past and no VOCs have been found since1998. Exposure to TCE and PCE will be eliminated when the Port connects to themunicipal water supply.

  4. Indoor air concentrations of TCE, PCE, 1,4-dichlorobenzene, and mixed xylenes at theCadet facility appear to be elevated. The level of TCE measured is particularly highalthough it is well below workplace standards. However, the single sampling roundconducted in March 2001 is not sufficient to determine actual exposure of workers toindoor air levels of VOCs. Therefore, exposure of workers to VOCs in indoor air atCadet represent an indeterminate health hazard.

  5. No apparent public health hazard exists from exposure to TCE in wells supplyingprocess water for Great Western Malting. These wells are not used for drinking and theestimated indoor air levels that might result from off-gassing inside the facility are below a level of health concern.

RECOMMENDATIONS/PUBLIC HEALTH ACTION PLAN

  1. DOH recommends indoor air sampling inside residential homes and crawl spaces in theFruit Valley Neighborhood.

    • DOH is available to assist with the development and review of an indoor airsampling plan. Results of indoor samples should be sent to the DOH forevaluation.

    • Future soil gas samples in the Fruit Valley Neighborhood should be collectedunder slabs or floors of structures that are considered to be at risk. When thiscannot be accomplished, enough samples should be collected adjacent to thesestructures so that a good estimate of average concentration can be made.

    • The Johnson & Ettinger vapor intrusion model contains useful guidance for soilgas sampling that should be consulted when developing a sampling plan.

  2. Continued sampling of indoor air for VOCs is necessary to better estimate exposure ofworkers at the Cadet facility. While VOC levels in indoor air at Cadet do not exceedworkplace standards, levels do exceed what is considered to be background for a typicalindoor air environment. High concentrations of VOCs in groundwater near Cadet may bea source.

PREPARER OF REPORT

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


REFERENCES

  1. Interim Action source Investigation Work Plan, Cadet Manufacturing Site, AGRA Earth& Environmental, Inc. March 2000.

  2. Memo from C. Rankine to S. Matthews, Rufener Property Groundwater Sampling. July23, 2001.

  3. Washington State Department of Ecology. Summary Score Sheet. Cadet ManufacturingCompany, Site Hazardous Assessment #99-01.

  4. Semi-Annual Groundwater Monitoring Report 2001, Cadet Manufacturing Company,AMEC. November 13, 2001.

  5. Letter to C. Rankine, Ecology, from B. Lary, AMEC Earth & Environmental, Inc.Additional Source Investigation, Cadet Manufacturing Company. February13, 2001.

  6. User's Guide for the Johnson and Ettinger (1991) Model for Subsurface Vapor Intrusioninto Buildings (Revised), Environmental Quality Management, Inc., for US EPA Officeof Emergency and Remedial Response. December 2000.

  7. Letter to J. Hamachek, Great Western Malting, from Maul Foster & Alongi, Inc. June 23, 2000.

  8. Cadet Manufacturing, Johnson & Ettinger Soil Gas and Groundwater Screening ModelSummary, B. Trejo. October 17, 2001.

  9. US Environmental Protection Agency. Trichloroethylene Health Risk Assessment:Synthesis and Characterization (External Review Draft). August 1, 2001.

  10. Agency for Toxic Substances and Disease Registry. Public Health Assessment GuidanceManual, Lewis Publishers, Chelsea, Michigan, 1992.

  11. McKone, TE. Household exposure models. Toxicology Letters. 1989; 49:321-39.

APPENDIX A: FIGURES

Site Location Map
Figure 1. Site Location Map

Site Plan
Figure 2. Site Plan


APPENDIX B: TABLES

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 completedexposure pathway. The dose estimates for each of these pathways are described in the discussionsection of the document. Maximum concentrations are used to calculate these doses, representinga "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 indrinking 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 tworoutes of exposure is equivalent to that of ingestion. This assumption is supported by ATSDRguidance although some mathematical models indicate that the inhaled dose for VOCsvolatilizing from drinking water can be several times higher than the ingested dose. Thefollowing exposure dose equation and exposure assumptions were used to calculate the dosesgiven below in Tables C1 and C2.

Ingestion Exposure AssumptionsIngested Dose - Drinking Water

various mathematical equations

Inhalation Exposure AssumptionsInhaled Dose - Workers

various mathematical equations


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 fromcontaminated soil gas and groundwater. Because of limitations associated with the depth of thesoil gas sampling (3-4 feet) in the FVN, only the slab-on-grade scenario was evaluated duringthe soil gas modeling. The same building scenario was used when modeling the groundwater toindoor air pathway. Because only limited modeling was conducted, the carcinogenic risks andnon-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 collectedusing a push probe technique. Table D1 summarizes the range of chemical concentrationsdetected 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 ofchlorinated solvent soil gas concentrations detected poses a health risk to people in the nearbyFVN. The model predicts steady-state indoor air chemical concentrations and incremental riskand/or hazard quotients associated with the soil gas concentration data.

The model operates under the assumption that the soil column properties are homogeneous andisotropic. 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 onlimited soil information available for the site. The groundwater temperature used for themodeling (12º C for western Washington) was extrapolated from average U.S. shallowgroundwater temperature data provided in the J&E guidance document.

Default values were used for vadose zone soil properties - soil dry bulk density, soil totalporosity, and soil water filled porosity. Default values were also used for averaging time forcarcinogens, averaging time for non-carcinogens, exposure duration, and exposure frequencywhen 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 wascalculated for TCE based on the proposed U.S. EPA cancer slope factor of 0.02 kg-day/mg. Thisslope factor is based on a worker inhalation exposure.

Table D2 summarizes the potential indoor air risk results associated with the maximumconcentration of each chemical in the soil gas. The incremental risks associated with themodeled 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
Soil Type*
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 airpathway using the slab-on-grade building scenario. Groundwater data obtained from the August2001 sampling round was used to predict the incremental risk and/or hazard quotient associatedwith the same chlorinated solvents evaluated during the soil gas modeling. The maximumgroundwater concentration of each of the five chemicals that were detected during the soil gasmonitoring 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 sitevaries seasonally with precipitation. Groundwater depth is shallowest in the spring,approximately 8 feet bgs. The deepest groundwater depths occur in the fall, approximately 21feet bgs. The groundwater-screening model was run using both depths. For modeling purposes, itwas assumed that the August 2001 results represented groundwater concentrations that would bedetected throughout the year. Consistent with the soil gas modeling, an estimated groundwatertemperature of 12ºC was used.

The groundwater screening model, like the soil gas model, was run using three different soiltypes (sand [S], loamy sand [LS], and sandy loam [SL]). Default values were used for vadosezone 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 1,1dichloroethene, cis 1,2-dichloroethene, tetrachloroethene, and 1,1,1-trichloroethane were usedduring the modeling. A URF was calculated for TCE based on the proposed U.S. EPA cancerslope 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 maximumconcentration of each chemical in the shallow groundwater associated with the slab-on-gradebuilding scenario. The incremental risks associated with the modeled indoor air concentrationsof 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


CERTIFICATION

This Health Consultation was prepared by the Washington State Department of Health under acooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). Itis in accordance with approved methodology and procedures existing at the time the healthconsultation 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



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