PUBLIC HEALTH ASSESSMENT
BOOMSNUB/AIRCO SUPERFUND SITE
VANCOUVER, CLARK COUNTY, WASHINGTON
The Boomsnub/Airco Superfund site is located in the south end of Hazel Dell, Washington,an unincorporated town in Clark County, Washington. The site consists of the formerBoomsnub chrome plating facility where a number of chromium releases occurred to soil andgroundwater; BOC Gases (formerly Airco), a gas manufacturing facility where volatileorganic compound releases occurred to soil and groundwater; and a commingled plume ofmetals (primarily chromium) and volatile organic compounds in groundwater within theshallow, Alluvial aquifer and to a lesser extent in the deeper, Upper Troutdale aquifer.
The Washington State Department of Health (WDOH) conducted a public health assessmentfor the site in 1995 and determined that the site was a public health hazard because it posed athreat to the municipal water supply which draws water from the Upper Troutdale aquifer. WDOH also determined that the Boomsnub facility, prior to its closure in 1994, represented ahealth hazard to site workers exposed to chromium. As a result of its findings, WDOH madea number of recommendations: reduce or prevent exposure to contaminants; identify sourcesof contamination; and educate the public about the health implications of the site.
Since 1995, additional soil and groundwater data were collected at the site by the U.S.Environmental Protection Agency (EPA) and BOC Gases. WDOH evaluated this new data aspart of an earlier draft of this public health assessment.
Surface soil at the Boomsnub and adjacent properties was further investigated by EPA as partof a remedial investigation at the site. Although a number of metals and organic compoundswere detected, the concentrations of the chemicals in surface soil pose no apparent publichealth hazard.
Subsurface soil investigations were also conducted since 1995 at the Boomsnub and BOCGases properties. Elevated concentrations of volatile organic compounds were detected insubsurface soil and soil gas at the BOC Gases property. Metals and some organic compoundswere detected in subsurface soils at the Boomsnub and adjacent properties and some volatileorganic compounds were also detected in soil gas. No one is currently being exposed to thesesubsurface contaminants and therefore, no health threat exists.
A groundwater pump and treatment system has operated in the shallow Alluvial aquifer at thesite since 1990 to treat the chromium and volatile organic contaminated groundwater. Although the chromium and volatile organic compound concentrations have been reduced asa result of the pump and treatment system, the contaminant plume still poses a threat toprivate wells in the shallow aquifer. The plume also poses a threat to the municipal watersupply wells located in the underlying, deeper Upper Troutdale aquifer. The municipal wellsserve approximately 135,000 people in the City of Vancouver as well as 22,000 homes inHazel Dell and other unincorporated areas north of Vancouver.
Metals (primarily chromium), and volatile organic compounds have also been detected at lowlevels at some monitoring wells and water supply wells in the deeper, Upper Troutdaleaquifer in an area that extends downgradient of the BOC Gases and Boomsnub properties. The boundaries of the groundwater contamination in the Upper Troutdale aquifer, however,have not been determined. The detected contaminants pose a potential threat to private wellsin the Upper Troutdale aquifer.
The site continues to be a public health hazard because of the groundwater contamination. Asa result, WDOH recommends that a number of actions be taken at the site: boundaries of thegroundwater contamination in the Alluvial and Upper Troutdale aquifers should continue tobe defined; groundwater contaminants should be prevented from spreading further; andgroundwater and soil contaminant concentrations should be eliminated or reduced to levelsthat are protective of human health. WDOH also recommends that abandoned wells in orclose to the identified paths of the contaminated groundwater and public and private wellslocated within and near the areas of contaminated groundwater be closely monitored. Adoor-to-door survey should be conducted to identify all existing wells in the areas ofcontaminated groundwater within the Alluvial and Upper Troutdale aquifers. Wells withinareas of contaminated groundwater that act as channels for transmitting contaminants should be eliminated.
The Washington State Department of Health (WDOH) has prepared this public healthassessment in response to new soil and groundwater data collected at the Boomsnub/AircoSuperfund site since 1995 when WDOH conducted its initial public health assessment. Thenew information was used to further evaluate the health hazards associated with the site.
Groundwater in the vicinity of the site serves as a public and private water supply source. The potential impacts of the site contamination on groundwater remain a significant healthconcern for the community and the local public water suppliers. Worker exposure tocontaminated soils is also a health concern raised by some site workers.
The Boomsnub/Airco Superfund site is located in Hazel Dell, an unincorporated town, inClark County, Washington. The site consists of the Boomsnub and BOC Gases propertieswhich are located south of the intersection of NE 47th Avenue and NE 78th Street as well astwo areas of groundwater contamination that extend west of NE 47th Avenue (Figure 1).
The former Boomsnub facility was located on less than 1 acre of land; BOC Gases occupiesapproximately 11 acres. Boomsnub, a relatively flat property, is bordered by a railroad right-of-way to the west; commercial businesses or light industry to the north and south; and NE47th Avenue to the east. BOC Gases, also a relatively flat property, is bordered by NE 47thAvenue and NE 78th Street to the west and north, respectively; a light industry to the south;and an industrial and residential area to the east.
Boomsnub operated a chrome plating facility at the property from 1967 to June 1994. Duringits operation, a number of chromium releases occurred that resulted in the contamination ofsoil and, ultimately, groundwater. Sources of chromium contamination included spills andleaks of chromic acid from an above-ground storage tank, plating pits, and concrete linedfloor pits.1, 2 The Washington State Department of Ecology (Ecology) began investigating thechromium contamination at the Boomsnub property in 1987 and installed a groundwatertreatment system in the uppermost aquifer at the property in 1990 to collect and removechromium. Volatile organic compounds were detected by Ecology during its operation of thesystem. The groundwater treatment system was expanded to treat the additionalcontaminants.1, 2
BOC Gases, a compressed and liquified gas manufacturing and distributing facility thatbegan operating in 1964, was the suspected source of the volatile organic contamination. BOC Gases began soil and groundwater investigations at its property in 1991. Volatileorganic contaminated water and sediment were discovered in a dry well on BOC Gases'property during the investigations. The dry well, located above the Alluvial aquifer, was ashallow well that was used for waste water and storm water infiltration. Water and sedimentwere removed in March 1994 because they were the likely sources for the volatile organiccompounds detected in groundwater.2
In June 1994, the Environmental Protection Agency (EPA) took over as the lead regulatoryagency for the Boomsnub/Airco site. EPA excavated and removed approximately two-thirdsof the chromium-contaminated soils from the Boomsnub property.2 The removal action wascompleted in late 1994.
Because of the continuing movement of the contaminant plume in the shallow, Alluvialaquifer and concerns about the quality of the groundwater being used by private well ownersin or near the plume, WDOH, in cooperation with the Southwest Washington Health District,the Department of Ecology, the City of Vancouver, Clark Public Utilities, and the EPA issueda news release in July 1994 advising residents who were using private wells in the vicinity ofthe Boomsnub/Airco site to connect to the public water system.1 This recommendation wasmade to ensure a continuing safe water supply for people who had wells in or adjacent to the contaminant plume.1
WDOH completed a public health assessment of the site in 1995 and determined that the sitewas a public health hazard because of the threat it posed to the municipal water supply wellswhich draw water from the Upper Troutdale aquifer.1 WDOH also determined that theBoomsnub facility, prior to its closure in 1994, represented a health hazard to site workersdue to their exposure to chromium.1 As a result of its findings, WDOH made a number ofrecommendations: reduce or prevent exposure to contaminants; identify sources ofcontamination; and educate the public about the health implications of the site.1
The groundwater treatment system has continued to operate since EPA took over the site in1994. The system has been expanded and EPA shares responsibility for the operation andmaintenance of the system with BOC Gases.
On March 11, 1999, WDOH staff visited the Boomsnub/Airco site.3 EPA conducted a sitetour of the Boomsnub property and pointed out various features on the BOC Gases propertyfrom the western-most fence line. Both the Boomsnub and BOC Gases properties are fenced. EPA controls access to the Boomsnub property; BOC Gases controls access to its property.
Surface soils were exposed in some areas of the Boomsnub property; other areas were pavedor covered by structures. Some adjoining properties that were affected by Boomsnub'soperation or by remediation activities conducted by EPA also had exposed surface soils. Much of the BOC Gases property appears to be paved or gravel covered.
A groundwater treatment system consisting of an ion exchange unit and an air stripping toweris located at the Boomsnub property. The system, operated by EPA and BOC Gases, wasdesigned to remove chromium and volatile organic compounds from a groundwatercontaminant plume located in the uppermost aquifer. The plume extends approximately4,400 feet west of the site. Approximately 100 gallons of groundwater were being treated perminute. The treated groundwater is discharged to the City of Vancouver's sewer system.
In the course of their remedial investigation, EPA determined that the groundwatercontaminant plume in the uppermost aquifer had migrated beyond the range of thegroundwater extraction system. During the site visit, EPA was completing the installation oftwo additional extraction wells and three additional monitoring wells east of NE 30th Avenueto contain and monitor the plume. Contaminated groundwater collected near the toe of theplume, east of NE 30th Avenue, was being hauled by tanker truck to the Boomsnub property for treatment.
When EPA took over the Boomsnub/Airco Superfund site in 1994, the site was divided intothree operable units: Boomsnub Soil Operable Unit, BOC Gases Soil Operable Unit, andSite-Wide Groundwater Operable Unit (Figure 1). Environmental investigations wereconducted at each of these areas in subsequent years.
- Boomsnub Soil Operable Unit - Surface and subsurface soil samples were collected andanalyzed by EPA at the Boomsnub Soil Operable Unit as part of the 1997 remedialinvestigation to determine the nature and extent of metals and a variety of organiccontaminants that remained after the chromium contaminated soils were removed in1994. The Boomsnub Soil Operable Unit consists of the Boomsnub property where thechromium releases occurred; adjacent properties that were affected by releases fromBoomsnub's operations (northern portion of LaValley property adjacent to the Boomsnubproperty); or by releases that occurred during EPA's soil removal activities at theBoomsnub site (Voorhies, Heuvel, and Railroad right-of-way) (Figure 2).
- Site-Wide Groundwater Operable Unit - EPA and BOC Gases investigated the nature andextent of groundwater contamination at and adjacent to the Site-Wide GroundwaterOperable Unit during the 1997 remedial investigation. Additional monitoring wells wereinstalled and samples were collected and analyzed for metals, including chromium, andvolatile organic compounds. The contaminated portions of the Alluvial and the UpperTroutdale aquifers make up the Site-Wide Groundwater Operable Unit (Figure 1).
- BOC Gases Soil Operable Unit - While EPA conducted their remedial investigation, BOC Gases concurrently conducted various soil investigations at the BOC Gases SoilOperable Unit (Figure 1). The soil data collected by BOC Gases, along with soil and soilgas data from 1994, helped to determine the nature and extent of volatile organiccontamination at the operable unit. The soil gas data collected by BOC Gases also helpedto determine if significant concentrations of volatile organic compounds had migratedfrom the BOC Gases Operable Unit to adjacent properties.
Based on the 1990 census, Hazel Dell has a population of approximately 15,000 residents.1 Vancouver, which is adjacent to and south of Hazel Dell, has a population of approximately 135,000 residents.4 Approximately 95 percent of the area population are white; Asians or Pacific Islanders account for 2.3 percent of the population and 2.2 percent of the population are of Hispanic origin (persons of Hispanic origin may be of any race).1
The Boomsnub and BOC Gases properties are located in a predominantly mixed commercialand light industrial area. However, some private residences are located in the vicinity of thesite. The contaminated groundwater plumes are located in an area that is mixed commercial, light industrial, residential, and agricultural.2
The City of Vancouver and the Clark Public Utilities own and operate water supply wellswest of the site. There are also several private wells in the area.
The primary source of public and private potable water for the Vancouver and Hazel Dellarea is the Upper Troutdale aquifer which is located approximately 150 feet below groundsurface.1, 2, 5 Groundwater in the Upper Troutdale aquifer appears to flow to the southwest(Figure 1). Much of Hazel Dell and other unincorporated areas north of the City ofVancouver are serviced by Clark Public Utilities, whose nearest well is locatedapproximately 1 mile west of the Boomsnub and BOC Gases properties in the UpperTroutdale aquifer.2 Clark Public Utilities currently services 22,000 homes.4 The City ofVancouver also has a water supply well approximately 1 mile west of the Boomsnub andBOC Gases properties in the Upper Troutdale aquifer. The City of Vancouver well servicesapproximately 135,000 residents in Vancouver.4
The Upper Troutdale aquifer underlies an alluvial aquifer which is also a source of potablewater for private wells near the site.2, 5 The Alluvial aquifer is relatively shallow,unconfined, and separated from the Upper Troutdale aquifer by a silty, clay aquitard ofvarying thickness. Groundwater in the Alluvial aquifer flows west/northwest from theBoomsnub and BOC Gases properties.2
In preparing the Public Health Assessment, the Washington State Department of Health relieson the information provided in the referenced documents and assumes that adequate qualityassurance and quality control measures were followed with regard to sampling procedures,chain-of-custody, laboratory procedures, and data reporting. The validity of the analyses andthe conclusions drawn for this Public Health Assessment are determined by the availability and reliability of the referenced information.
The public health effects associated with a site depend on two factors: the contaminants ofconcern and how people come into contact with the contaminant (i.e., exposure pathways).
Contaminants of concern are those chemicals found at a site that may cause health effects. However, not all chemicals found at a site are chemicals of concern and not all chemicals ofconcern are a health hazard.
In order for an exposure to a contaminant of concern to occur, all the elements of an exposurepathway must be in place. Exposure pathways are divided into completed and potentialpathways and can be current, past, or future exposures. A completed exposure pathwayconsists of five elements: a contaminant source; environmental media that transportcontaminants from the source (e.g., soil, groundwater, air); a point where people contactcontaminated media (e.g., tap water); route of exposure by which a contaminant enters thehuman body (e.g., inhalation, ingestion, dermal contact or absorption); and a receptorpopulation that is exposed to contaminants. A potential exposure pathway exists when some,but not all, of the five elements are present and the potential exists that the missingelement(s) have been present, are present, or will be present in the future.
The completed and potential exposure pathways for each operable unit at theBoomsnub/Airco Superfund site are described below and summarized in Tables 1 and 2,respectively. The contaminants of concern for the completed exposure pathways arepresented in Table 3. Appendix A summarizes how chemicals of concern were selected.Appendix B provides exposure assumptions that were used to calculate exposure doses. Appendix C describes how non-cancer adverse health effects and cancer risks are evaluatedfor each chemical of concern.
The Boomsnub Soil Operable Unit consists of the Boomsnub property where the chromiumreleases occurred; adjacent properties that were affected by releases from Boomsnub'soperations (northern portion of the LaValley property adjacent to the Boomsnub property); orby releases that occurred during EPA's soil removal activities at the Boomsnub site in 1994(Voorhies and eastern portion of the Heuvel properties and the railroad right-of-way) (Figure2). The properties within the operable unit are either light industrial or commercial facilitiesand contain elevated levels of organic and inorganic contaminants.
The present receptor population includes commercial and industrial workers at the LaValley,Voorhies, Heuvel, and railroad right-of-way properties who may have contact with soils andcan be exposed to contaminants through incidental ingestion, dermal contact, or throughinhalation of fugitive dust. Remedial workers at the Boomsnub property were not considereda receptor population for this public health assessment because site activities at theBoomsnub property are conducted under a site-specific health and safety plan which isdesigned to reduce or prevent remedial worker exposure to contaminants. Although somescattered residences are located within the vicinity of the operable unit, they are unlikely to beexposed to the contaminants because the properties within the operable unit are fenced oraccess is otherwise limited. It is anticipated that future exposure to contaminants will also belimited to commercial and industrial site workers since the operable unit is surrounded by light industrial/commercial businesses.
A completed exposure pathway exists for workers exposed to surface soils via incidentalingestion, dermal contact, or inhalation of fugitive dust at the Voorhies property, the easternportion of the Heuvel property, northern portion of the LaValley properties, and the railroadright-of-way located within the Boomsnub Soil Operable Unit (Table 1). It wasconservatively assumed that workers were exposed to the contaminants of concern 5 days aweek for 30 years. The cancer and non-cancer health effects associated with eachcontaminant of concern are summarized below.
Chromium is present in the environment in several different forms: Chromium(0),chromium(III), and chromium(VI). Chromium(III) occurs naturally in the environment. Chromium (0) and chromium (VI) are generally produced by industrial processes. Because itcan occur naturally in the environment, low levels of chromium are generally present in thesoil. The natural background concentration of chromium in Clark County is approximately27 mg/kg.6
Elevated total chromium concentrations were detected in surface soils (0-6 inches) along thenorthern portion of the LaValley property, the Voorhies property and the eastern portion ofthe Heuvel property, and the railroad right-of-way.2 Chromium was also detected at theBoomsnub property but as stated above, the Boomsnub property is not being evaluated aspart of the public health assessment because work at the property is being done under a healthand safety plan which is designed to reduce or prevent remedial worker exposure tocontaminants. Figure 4 provides the total chromium concentrations detected in surface soilsat all the properties within the Boomsnub Soil Operable Unit.
The maximum concentration of chromium (VI) in surface soils was detected at the Voorhiesproperty. Although neither total chromium nor chromium (VI) was detected in surface soilsabove human health comparison levels at the northern portion of the LaValley property, theVoorhies property, the eastern portion of the Heuvel property, and the railroad right-of-way(Figure 3), it was carried forward for further evaluation since it was a chemical of concernduring the previous public health assessment.
Chromium is an inhalation human carcinogen but is not a carcinogen by the ingestion anddermal exposure routes. However, it can cause non-cancer health effects through theingestion, inhalation, and dermal exposure routes.
Non-cancer health effects are not anticipated for workers through incidental ingestion ordermal contact with the maximum total chromium and chromium (VI) levels detected at thenorthern portion of the LaValley property, the Voorhies property, the eastern portion of theHeuvel property, and the railroad right-of-way. Chromium (VI), an inhalation carcinogenand non-carcinogen above soil concentrations of 230 mg/kg, was detected in surface soilsamples at those properties but at concentrations below 230 mg/kg.7 Therefore, no adversehealth effects or significant cancer risk are expected through inhalation of chromiumcontaminated fugitive dust.
Arsenic was detected by EPA above soil screening values in only one surface sample alongthe eastern portion of the railroad right-of-way (32.3 mg/kg) near the Voorhies property. Like chromium, arsenic is also a naturally occurring element. Because it occurs naturally inthe environment, low levels of arsenic are generally present in soil. The natural backgroundconcentration for arsenic in Clark County is approximately 6 mg/kg.6
Arsenic is normally taken into the body in small amounts through inhalation and ingestion of drinking water and food. Of these, food is the largest source of arsenic.8 If arsenic contaminated dust is inhaled, the dust particles settle onto the lining of the lungs.8 For dermal exposure, only a relatively small amount will go through the skin into the body, so this is not usually a concern.8
Non-cancer health effects for workers are not anticipated to result from incidental ingestionor dermal contact with arsenic at the maximum concentration detected at the railroad right-of-way (32.3 mg/kg). An increased cancer risk through incidental ingestion and dermal contact,however, could result from continual exposure to arsenic at this concentration. Themaximum concentration, however, probably represents a "hot spot" and exposure to arsenicat this concentration would probably occur infrequently. WDOH, therefore, considers thecancer risk from exposure to arsenic along the railroad right-of-way insignificant.
The site is located in an area that receives significant rainfall throughout the year. Exposureto arsenic-contaminated dust would therefore be limited to the driest summer months. Neither cancer nor non-cancer health effects are anticipated to result from exposure toarsenic-contaminated fugitive dust during this limited exposure period.
Beryllium was detected from 0.52 to 0.81 mg/kg in a number of surface samples along thenorthern portion of the LaValley property, the Voorhies property, the eastern portion of theHeuvel property, and the railroad right-of-way.2 The highest concentration was detected at0.81 mg/kg at the Voorhies property.
Beryllium is also a naturally occurring element. Because it occurs naturally in theenvironment, low levels of beryllium are generally present in the soil. The naturalbackground concentration for beryllium in Clark County is 2 mg/kg, approximately two andone half times greater than the maximum concentration detected at the four properties.6 Beryllium occurs as an impurity in coal and fuel oil and is emitted into the air throughchimneys.9
Beryllium can enter the body through inhalation of dust particles suspended in the air or byeating food or drinking water which contains it.9 If it is swallowed, it leaves the body in afew days.9 However, if it is inhaled, it may take months or years before the body rids itself ofthe beryllium.9 Beryllium can be harmful when you breathe it. The effects depend on howmuch and how long a person is exposed to it. Beryllium does not enter the body from skincontact unless the skin is scraped or cut and beryllium particles become embedded in thewound.9
Non-cancer health effects are not anticipated for workers who may be exposed to beryllium atthe maximum concentration (0.81 mg/kg) through incidental ingestion or dermal contact. This is consistent with findings from studies done on humans and animals exposed toberyllium. The estimated risk to site workers exposed to beryllium at the maximumconcentration would not result in a cancer risk that the WDOH considers significant. This isalso consistent with studies on beryllium exposure.
The four properties are located in an area that receives significant rainfall throughout theyear. Exposure to beryllium-contaminated dust would therefore be limited to the driestsummer months. Neither cancer nor non-cancer health effects are anticipated to result fromexposure to beryllium-contaminated fugitive dust at the maximum concentration (0.81mg/kg) during this limited exposure period.
Carcinogenic Polynuclear Aromatic Hydrocarbons (CPAHs)
Carcinogenic polynuclear aromatic hydrocarbons (CPAHs) were detected in surface soil atthe Voorhies property, and the railroad right-of-way. CPAHs were also detected behind thebuildings at the LaValley property, just south of the Boomsnub property. The highest CPAHconcentrations (9.7 mg/kg) occurred along the east side of the railroad right-of-way.
CPAHs are products of incomplete burning of fossil fuels, wood, garbage, fuels, and otherorganic substances and are ubiquitous in the environment. CPAHs can enter the body if skincomes into contact with soil that contains CPAHs.10 However, they do not tend to be storedin the body for a long time.10 CPAHs that enter the body are excreted within a few days.10 CPAHs can also enter the body through the lungs when a person breathes air that containsCPAH-contaminated dust or through incidental ingestion of CPAH contaminated soil.10
Benzo(a) pyrene, a CPAH with the highest potential risk, was selected as a conservativesurrogate comparison value for evaluating CPAHs. Based on this very conservativecomparison value, it was determined that four additional cancers would occur in a populationof 10,000 site workers through incidental ingestion and dermal contact with the maximumCPAH concentration (9.7 mg/kg). The actual risk posed by the CPAHs at the properties,however, would be significantly lower than calculated because benzo(a) pyrene only makesup a small portion of the CPAHs detected and likely would not exceed a level WDOHconsiders significant.
The site is located in an area that receives significant rainfall throughout the year. Exposureto CPAH-contaminated dust would therefore be limited to the driest summer months. Neither cancer nor non-cancer health effects are anticipated to result from exposure toCPAH-contaminated fugitive dust at the maximum concentration (9.7 mg/kg) during thislimited exposure period.
Chlordane was detected at 0.071 mg/kg in one surface soil sample along the eastside of therailroad right-of-way, adjacent to the Voorhies property. Chlordane is a man-made chemicalthat was used as a pesticide in the U.S. from 1948 to 1988. In soil, it attaches strongly to soilparticles in the upper layers of soil and is unlikely to enter groundwater. It can remain in soilfor over 20 years.11 Chlordane is sufficiently persistent that it may travel long distances andbe deposited on land or in water far from its source.11
The most common chlordane exposure occurs from ingesting contaminated food.11 However, chlordane can enter the body through dermal contact with contaminated soil.11 Non-cancer health effects for workers are not anticipated to result from incidental ingestion or dermal contact with chlordane at the maximum concentration detected at the railroad right-of-way (0.071 mg/kg). An increased cancer risk through incidental ingestion and dermal contact could result from continual exposure to chlordane at this concentration. However, because this is a railroad right-of-way and only one sample had significant chlordane concentrations, workers are unlikely to be exposed to these concentrations on a continual basis. Therefore, the cancer risk associated with the maximum concentration is not anticipated to exceed a level WDOH considers significant.
No apparent public health hazard exists for workers exposed to the contaminants of concernin surface soil along the northern portion of the LaValley property, the Voorhies property, theeastern portion of the Heuvel property, or the railroad right-of-way at the Boomsnub SoilOperable Unit. It was conservatively assumed that workers were exposed to thecontaminants of concern 5 days a week for 30 years. Actual exposure is probablysignificantly less since activities associated with the properties within the Operable Unit would result in less frequent contact with surface soils.
To reduce the chance of exposure, workers should continue to limit their exposure to surfacesoils along the northern portion of the LaValley property, the Voorhies property, the easternportion of the Heuvel property, and the railroad right-of-way at the Boomsnub Soil Operable Unit.
Metals and organic compounds have been detected above soil screening levels in subsurfacesoils along the northern portion of the LaValley property, the Voorhies property, the easternportion of the Heuvel property, and the railroad right-of-way at the Boomsnub Soil OperableUnit (Table 3). They have also been detected in subsurface soils at the Boomsnub property. Volatile organic compounds that appear to be related to releases at the BOC Gases propertyhave been detected in soil gas above air screening values at the operable unit.
It is anticipated that future site use at the Boomsnub Soil Operable Unit will remaincommercial or light industrial. The subsurface contamination, therefore, may pose a threat toworkers through ingestion, dermal contact, and inhalation if activities at the propertiesinvolve contact with contaminated subsurface soils.
Contact with subsurface soils at the Boomsnub Soil Operable Unit may result in healtheffects if significantly high concentrations of soil contaminants are encountered duringactivities at the properties. Soil gas may also pose a threat to human health if it isencountered through exposure to subsurface soils.
Contact with subsurface soils should be minimized to prevent potential health effects. TheWDOH should be notified by property owners, tenants, or public agencies that may beinvolved in the development of the properties about significant changes at the properties thatmay result in worker exposure to contaminated subsurface soils or soil gas. If site conditions change, WDOH can evaluate whether human health effects may occur.
The BOC Gases Soil Operable Unit consists of the BOC Gases property, an industrial facilitylocated east of the Boomsnub Soil Operable Unit. Based on environmental investigationsconducted at the BOC Gases property, it was determined that the property was the source ofvolatile organic compounds detected in groundwater since the mid-1990s.2, 12, 13, 14 Past andcurrent exposure to contaminated soils at the property are limited to workers. It is anticipatedthat future exposure to contaminants at the Operable Unit will also be limited to workerssince the property is located in a predominantly light industrial/commercial business area.
Limited data collected from the property indicates that the only chemical of concern detectedin surface soils was trichloroethylene (TCE) which was detected at a maximum concentrationof 250 mg/kg in sediments at a small dry well located in the western portion of the BOCGases property. Most of the sediment in the dry well was subsequently removed in 1994. Sediments remaining in the dry well were retested for TCE after the removal was completed. The residual TCE concentration after removal was 6.9 mg/kg in the dry well which is belowthe 60 mg/kg human health comparison value for TCE.15
BOC Gases also collected and analyzed subsurface soils and soil gas for volatile organiccompounds during its environmental investigations in an attempt to identify sources of thevolatile organic contaminants at the site.2, 16 Subsurface soils and soil gas contained elevated levels of volatile organic compounds.
No completed exposure pathways exist at the BOC Gases Soil Operable Unit. Workers at the BOC Gases property are exposed to surface soils. However, there are no contaminants of concern in surface soils. Much of the BOC Gases property is paved or covered with structures. This prevents or greatly reduces volatile organic compounds in soil gas from discharging into the air.
As described above, volatile organic compounds have been detected in subsurface soils andsoil gas at the BOC Gases Soil Operable Unit.
It is anticipated that future property use at the BOC Gases Soil Operable Unit will remaincommercial or light industrial. The subsurface contamination, therefore, may pose a threat toworkers through ingestion, dermal contact, and inhalation if site activities involve contactwith the contaminated subsurface soil or exposure occurs to workers through contact withsoil gas in subsurface soils.
Contact with subsurface soils at the BOC Gases Soil Operable Unit may result in healtheffects if significantly high concentrations of soil contaminants are encountered during siteactivities. Soil gas may also pose a threat to human health if it is encountered throughexposure to subsurface soils.
Contact with subsurface soils should be minimized to prevent potential health effects. TheWDOH should be notified by property owners or tenants or public agencies that may beinvolved in the cleanup or the development of the property about significant changes at theproperty that may result in exposure to contaminated subsurface soils or soil gas so it can evaluate whether human health effects may occur.
A number of groundwater investigations have been conducted at the site by Ecology, EPA,and BOC Gases since the late 1980s. The information collected from these investigationswas used by EPA to determine the nature and extent of a commingled plume of groundwatercontamination in the Alluvial aquifer (Figure 1). The information was also used to determinewhether contamination had migrated into the underlying Upper Troutdale aquifer (Figure 1).
The contaminated groundwater identified in the Alluvial and Upper Troutdale aquifers duringthe investigation makes up the Site-Wide Groundwater Operable Unit. The Site-WideGroundwater Operable Unit covers a significant area to the west of the Boomsnub and BOCGases Soil Operable Units and consists of groundwater contaminated with metals (primarilychromium) and volatile organic compounds.
A commingled plume of metals (primarily chromium) and volatile organic contaminatedgroundwater is located in the Alluvial aquifer. It was determined from the remedialinvestigation that the Alluvial aquifer plume is approximately 4,400 feet in length andapproximately 900 feet wide.2 The contamination in the Alluvial aquifer originates at theBoomsnub/Airco site and moves west/northwest toward NE 30th Avenue.2 Based onanalytical results from new monitoring and extraction wells, EPA has determined that theplume extends to just east of 30th Avenue NE (Figure 1).
The concentrations of a number of metals and volatile organic compounds in the Alluvialaquifer exceed groundwater screening levels.2 However, according to existing records, thereare currently no known public or private wells drawing water from this contaminant plume.2,5, 17 One private water supply well is located in the plume but the well was decommissionedin 1993 before the metals and volatile organic groundwater contaminants reached the well.5, 18 There are other private wells located adjacent to the Alluvial aquifer contaminant plume. Clark Public Utilities' records indicate that some of the residents with water supply wellsnear the contaminant plume in the Alluvial aquifer have connected to the public watersystem.5
Upper Troutdale Aquifer
Metals (primarily chromium) and volatile organic contaminated groundwater have beendetected in the Upper Troutdale aquifer. The Upper Troutdale aquifer contamination islocated near the eastern end of the Boomsnub/Airco site and extends toward the southwest. The areal extent of the contaminated groundwater in the Upper Troutdale aquifer is unknown(Figure 1). The contaminants of concern consist of low levels of arsenic, lead, chromium,and volatile organic compounds. The contaminant concentrations detected in the UpperTroutdale aquifer are, however, significantly less than found in the Alluvial aquifer.
There are a few private water supply wells located in the contaminated portion of the UpperTroutdale aquifer but the residences are hooked up to the public water supply system.5 Thereare also other private water supply wells within the area of groundwater contamination in theAlluvial and Upper Troutdale aquifers but they are used for industrial cooling water,irrigation water, or not at all.2, 19 One residence with a private water supply well immediatelydowngradient of the contaminated area may be using the water for household purposes(drinking water, cooking, and bathing); another Upper Troutdale well located approximately1,500 feet downgradient of the contaminated area may also be used for household purposes.5
The City of Vancouver and Clark Public Utilities own and operate municipal drinking watersupply wells that are located in the Upper Troutdale aquifer. It is unknown whether thesewells could potentially be affected by the contamination in the Upper Troutdale aquiferbecause limited groundwater flow data is available for the Upper Troutdale aquifer.2
Currently, no known water supply wells located in the contaminated portion of the Alluvialand Upper Troutdale aquifers are withdrawing groundwater for potable water use. Therefore,no completed exposure pathways currently exist for the Site-Wide Groundwater OperableUnit.
As described above, the Alluvial and Upper Troutdale Aquifers contain metals (primarilychromium) and volatile organic contaminants of concern above human health comparisonvalues. The contaminated groundwater poses a threat to human health through ingestion,dermal contact, and inhalation if groundwater is used as a potable water supply.
Use of the contaminated groundwater from the Alluvial or Upper Troutdale aquifers could result in exposure to metals and volatile organic compounds at levels of concern.
The Boomsnub/Airco site is categorized as a public health hazard because of the threat posedby the contaminated groundwater in the Alluvial and Upper Troutdale aquifers to municipaland private water supplies. Any new or existing water supply well installed in or adjacent tothe area of contaminated groundwater in the aquifers could result in exposure to metals(primarily chromium) and volatile organic compounds via ingestion, inhalation, or dermalcontact if the groundwater is not remediated.
EPA should expand its efforts to define and contain the groundwater contamination in theAlluvial and Upper Troutdale aquifers and remove or control the sources of contamination.
Municipal wells threatened by the groundwater contamination should continue to be closelymonitored for metals and volatile organic compounds.
A door-to-door survey should be conducted to identify all existing and abandoned wells in orclose to the identified path of the contaminated groundwater in the Alluvial and UpperTroutdale aquifers. People with private wells should be encouraged to connect to themunicipal water supply. Appropriate steps should be taken to eliminate existing orabandoned wells if they are acting as conduits for contaminant transport.
Private and small public water supply wells located within and near the perimeter of the contaminated groundwater in the Alluvial and Upper Troutdale aquifers that are used for domestic or business purposes should be closely monitored for metals and volatile organic compounds. The WDOH should be notified about any anticipated changes in groundwater use by property owners or tenants or agencies involved in overseeing groundwater use in the area so the WDOH can evaluate whether human health effects will result from exposure to groundwater contaminants.
The potential for exposure and subsequent adverse health effects are often increased foryoung children when compared with older children or adults. For example, children drinkmore water per body weight than do adults and, therefore, receive higher exposures thanadults. In addition to the potential for higher exposures of young children, the risk of adversehealth effects is also increased. ATSDR and WDOH recognize that children are susceptibleto developmental toxicity that can occur at levels much lower than those causing other typesof toxicity.
Neither current nor past exposure to contaminants has occurred to young children at the site. Future exposures, however, could occur if, for example, land use changes to residential orgroundwater within the contaminated areas is used as a potable water supply. WDOH shouldbe contacted by property owners or tenants or agencies so it can evaluate potential health effects associated with such proposed changes.
The Washington Department of Health (WDOH) participated in the April 22, 1999, ClarkCounty Hazardous Waste Task Force meeting in Vancouver, Washington, in order to presentinformation to the community about the purpose of the current Public Health Assessment andto gather community health concerns about the site. A questionnaire was also made availableat the meeting to provide the community with an additional opportunity to submit healthconcerns to WDOH.
The following health-related questions were posed by the public:
A resident expressed concern about the quality of the drinking water at the First Churchof God school because her child is a student at the school. The First Church of God islocated above the contaminant plume in the Alluvial aquifer.
The First Church of God obtains its water from the Clark Public Utilities. The ClarkPublic Utilities' wells are located outside the area of groundwater contamination. Thewells are closely monitored by Clark Public Utilities to ensure a safe public water supply.
A person that worked at the Boomsnub property for less than 1 month during some ofEPA's remedial activities wanted to know if his exposure to the contaminants couldaffect his health.
Workers involved in remedial activities at hazardous waste sites are required to conducttheir work in compliance with a site-specific health and safety plan. The health andsafety plan describes the contaminants found at a site and how workers need to protectthemselves from exposure to contaminants. Workers who follow the health and safetyplan are unlikely to be exposed to harmful levels of contaminants.
The Public Health Action Plan for the Boomsnub/Airco Superfund site is summarized below. The purpose of the Public Health Action Plan is to ensure that this public health assessmentnot only identifies public health hazards, but provides a plan of action designed to prevent ormitigate adverse human health effects resulting from exposure to hazardous substances in the environment.
- EPA, the Washington State Department of Ecology (Ecology), and BOC took severalremedial actions to address contaminants in soil and groundwater at the site. Some ofthese actions are ongoing and include groundwater treatment and soil removal anddisposal.
- EPA, Ecology, and BOC Gases conducted a number of environmental investigations andgroundwater monitoring events to assist them in determining the nature and extent ofcontamination in soil and groundwater.
- WDOH, in cooperation with the Southwest Washington Health District, the Departmentof Ecology, the City of Vancouver, Clark Public Utilities, and the EPA issued a newsrelease in July 1994 advising residents who were using private wells in the vicinity of theBoomsnub/Airco site to connect to the public water system. This recommendation wasmade to ensure a continuing safe water supply for people who had wells in or adjacent tothe contaminated groundwater.
- WDOH conducted a site visit in March 1999 in order to identify any potential exposurepathways to contaminants in soil, air, water, or food near the site.
- WDOH participated in a Clark County Hazardous Waste Task Force meeting in April1999 in order to gather community health concerns related to the Boomsnub/AircoSuperfund site.
- EPA will take appropriate and timely steps including the sampling of groundwatermonitoring wells, at an appropriate frequency, within and adjacent to the areas ofgroundwater contamination in the Alluvial and Upper Troutdale aquifers to ensure thatthe contaminated groundwater areas are defined and contained.
- EPA will continue to closely monitor public and private water supply wells, at anappropriate frequency, within and adjacent to the areas of groundwater contamination inthe Alluvial and Upper Troutdale aquifers to ensure that human health is not affected bygroundwater contaminants.
- WDOH will follow up on its recommendations to conduct a door-to-door survey toidentify all existing and abandoned wells in or close to the identified path of the areas of groundwater contamination in the Alluvial and Upper Troutdale aquifer.
- WDOH will discuss with EPA the need to take appropriate steps to eliminate existing or abandoned wells within the areas of groundwater contamination in the Alluvial andUpper Troutdale aquifers if the wells are acting as conduits for contaminant transport.
- EPA will continue to reduce or eliminate groundwater and soil contamination to levelsthat are protective of human health.
- Clark Public Utilities and the City of Vancouver will continue to closely monitor themunicipal wells threatened by the areas of groundwater contamination in the Alluvial andUpper Troutdale aquifers to ensure that human health is protected.
- The WDOH will prepare a fact sheet that explains the results of the Public HealthAssessment and the nature of the risk posed by the contaminants at the site.
Barbara J. Trejo
Public Health Advisor
Washington State Department of Health
Office of Environmental Health Assessments
WA DOH Designated Reviewer
Washington State Department of Health
Office of Environmental Health Assessments
ATSDR Designated Reviewer
Technical Project Officer
State Program Section
Agency for Toxic Substances and Disease Registry
|Pathway Name||Source||Environmental Media||Point of Exposure||Route of Exposure||Exposed Population||Time|
|Boomsnub Soil Operable Unit||Boomsnub||Surface Soil||Boomsnub and adjacent properties||Inhalation |
|Pathway Name||Source||Environmental Media||Point of Exposure||Route of Exposure||Exposed Population||Time|
|Boomsnub Soil Operable Unit||Boomsnub||Surface and Subsurface Soil |
|BOC Gases Soil Operable Unit||BOC Gases||Subsurface Soil |
|Site-Wide Groundwater Operable Unit - Alluvial Aquifer||Boomsnub BOC Gases||Groundwater||None||Inhalation |
|Residents with Private Wells||Future|
|Site-Wide Groundwater Operable Unit - Upper Troutdale Aquifer||Boomsnub BOC Gases||Groundwater||None||Inhalation |
|Vancouver and Hazel Dell Residents||Future|
|Contaminant||Soil Concentration||Background||Comparison Value|
|Carcinogenic PAHs (CPAH)||9.78||1.62||NA||0.1||CREG a|
|Total Chromium||1030||1010||27||2000||RMEG b|
J = Reported value is an estimate
NA = not applicable
a) Benzo(a) pyrene used as a surrogate for CPAHs
b) Comparison value for Chromium (VI)
- Washington State Department of Health. Public Health Assessment forBoomsnub/Airco, Vancouver, Clark County, Washington, CERCLIS No.WAD009624453, July 18, 1995.
- ICF Kaiser, Remedial Investigation Report, Boomsnub/Airco Superfund Site, Hazel Dell,Washington. Prepared for the Environmental Protection Agency - Region 10, Revision 0,October 1998.
- Boomsnub/Airco Superfund Site Visit Summary - March 11, 1999, Barbara Trejo,WDOH.
- Letter from John Rundquist, City of Vancouver, To Barbara Trejo, WDOH, dated June20, 1999.
- Summary of Private Wells in the Boomsnub/BOC Gases Vicinity, Steve Prather, ClarkCounty Public Utilities, April 19, 1999.
- Washington State Department of Ecology. Model Toxics Control Act Cleanup Levelsand Risk Calculations (CLARC II) Update, February 1996.
- Paustenback, D.J.; Meyer DM; Sheehan PJ; Lau V., Toxicology and Industrial Health1991, Vol. 7, No. 3, p. 159-196.
- Toxicological Profile for Arsenic (Update), ATSDR, August 1998.
- Toxicological Profile for Beryllium (Update), ATSDR, April 1993.
- Toxicological Profile for Polynuclear Aromatic Hydrocarbons (PAHs), ATSDR,December 1995.
- Toxicological Profile for Chlorodane (Update), ATSDR, May 1994.
- EA Engineering, Report of Investigation, Airco Industrial Gases, April 1992.
- EA Engineering, Phase III Soil and Groundwater Investigation, Airco Gases, July 1993.
- EA Engineering, Phase IV Subsurface Soil Investigation Report, BOC Gases, August1995.
- ICF Kaiser, Work Plan, Remedial Investigation/Feasibility Study, Boomsnub/Airco (BOCGases) Superfund Site, Hazel Dell, Washington, August 1997.
- EA Engineering, Phase IV Soil Vapor Survey Report, BOC Gases, July 1995.
- Telephone conversation between Barbara Trejo, WDOH, and Peter Contreras, EPAProject Manager, March 23, 1999.
- Telephone conversation between Barbara Trejo, WDOH, and Nic Anderson, First Churchof God, April 9, 1999.
- Telephone message to Barbara Trejo WDOH, from Debbie Yamamoto, EPA ProjectManager, March 29, 1999.
- Washington State Department of Ecology. The Model Toxics Control Act CleanupRegulation, Chapter 173-340 WAC, Amended January 1996.
- Washington State Department of Ecology. Model Toxics Control Act Cleanup Levelsand Risk Calculations (CLARC II) Update, February 1996.
- American Cancer Society Facts and Figures, 1998.