PUBLIC HEALTH ASSESSMENT
VANCOUVER, CLARK COUNTY, WASHINGTON
The Boomsnub/Airco Superfund National Priorities List (NPL) site involves two adjacent plants, Boomsnub and Airco. A commingled groundwater plume of volatile organic compounds (VOCs) and chromium emanates from the site. This site is in the north end of Hazel Dell, Washington, an unincorporated town of 15,500. Hazel Dell abuts the north side of Vancouver, which has a population of 55,450. Portland, Oregon is about ten miles south across the Columbia River. The site is classified a public health hazard because of the threat to the municipal water supply.
Contaminants from this site have not yet been detected in the municipal water supply which serves about 50,000 people. Chromium has been found in private wells near the site at levels not considered a public health threat. Most of the private well residences have connected to the public water supplies. Because of the large amount of chromium lost at Boomsnub, plant workers in the past may have had high levels of exposure. The Boomsnub operation at this site has been closed. No information has been found to assess possible worker health effects. The United States Environmental Protection Agency (EPA) is making a major effort to contain the plume by source removal and a pump and treat system.
Municipal water in the area is obtained from the Troutdale aquifer which is about 150 feet below ground surface. The Troutdale is a confined aquifer that underlies an unconfined alluvial aquifer. The contaminant plume from the site is in the alluvial aquifer. Clark County and Vancouver have a well field about a mile southwest and downgradient of the site. The municipal wells at risk provide water to more than 50,000 people. By May 1994, the chromium plume in the alluvial aquifer was over 3,300 feet west of the site. The level of chromium in groundwater at that distance is two parts per million (ppm).
Since 1968, many spills of chromic compounds have occurred at Boomsnub. In 1987, the Washington State Department of Ecology (Ecology) found chromium contaminated soil and groundwater at the site. Late in 1990, Ecology found volatile organic compounds (VOCs) at high levels commingled in the chromium plume. In September 1992, Airco was identified as a probable source of VOCs. Trichlorethylene (TCE) was found in groundwater at the Airco plant.
In 1990, Ecology began to treat the groundwater to capture and remove chromium. Between 1990 and 1994, the treatment system was expanded several times as the extent of contamination was realized. EPA took control of the treatment system in June 1994. The pump and treat system, which is still in operation, has thus far removed about six tons of chromium.
Chromium was detected in five private wells, each serving one family, near the site. In 1991, the chromium in private wells ranged from 0.0112 ppm to 0.292 ppm. By 1993, the well with 0.292 ppm was tested and found to contain 0.03 ppm. Another private well over 3,000 feet from the Boomsnub plating facility has had chromium levels of 0.014 ppm. These private wells have been closed and the residences have connected to the available municipal water supplies. During 1994, Bob Poss of the Washington Department of Health (WDOH), attended a meeting of the Hazel Dell Neighborhood Association. At this meeting most of the community's concerns pertained to monetary responsibilities for cleanup and future operations of Boomsnub at another location. No specific health concerns were heard at this meeting. A review of thirty 1994 newspaper articles on this site indicated that the primary concern is the threat that the groundwater plume posses to the county water supply.
In the past, Boomsnub represented a health hazard to on-site workers exposed to chromium. Boomsnub claimed to have thirty workers at their plant. About three employees at a time may have worked in the plating operation. It is believed that these workers came in contact with high levels of chromic product and contamination which were incidentally ingested or inhaled as dust or vapor. At this time, the number of workers exposed to chromium at Boomsnub, and their possible health effects are unknown. The plant stopped operation in June of 1994.
Lung cancer was determined to be the only possible health outcome associated with chromium exposure as a result of the completed pathway, as it relates to exposure of on-site workers. The 1992 age-adjusted lung cancer incidence rate for Clark County was lower than the rate for Washington State. While these data do not indicate an excess of lung cancer for residents of Clark County as a whole, they do not rule out the possibility that subpopulations in smaller geographic areas of the county experienced excesses.
Environmental agencies should continue the effort to contain the plume of contamination and remove the sources of contamination. Municipal water supplies threatened by the plume of contamination should continue to be closely monitored for chromium and VOCs. An area-wide investigation should be conducted to identify all significant sources of chromium and VOCs. A private water well survey of the area should be done. People with private wells in the shallow aquifer should be encouraged to connect to the available city water supply.
The Boomsnub/Airco Superfund National Priorities List (NPL) site is at the intersection of Northeast 47th Avenue and 78th Street in Hazel Dell, an unincorporated town in Clark County, Washington (Figure 1). Hazel Dell has a population of about 15,500, and is adjacent to and north of Vancouver, which has a population of about 55,450. The Boomsnub plant is on less than one acre, while Airco occupies about 14 acres. Both plants have been proposed as one NPL site because a commingled plume of chromium and volatile organic compounds (VOCs) in groundwater emanates from the site.
In 1987, the Washington State Department of Ecology (Ecology) found chromium in soil and groundwater at Boomsnub. The VOCs were not detected until 1990 (25). The first known major release of chromium occurred more than 20 years ago when Boomsnub's aboveground chromic acid tank failed. It is estimated that about 5,000 gallons of chromic acid plating solution was lost in this 1968 spill (26).
Since 1967, metal plating has been done at Boomsnub by either of its subsidiaries, Pioneer Plating (1967-1978) or Pacific Northwest Plating Company [PNWP] (1979-1994) (4). In 1987, Boomsnub began to collect environmental samples. The first analytical results revealed low levels of hexavalent chromium on-site in the soil and groundwater (4). From 1987 to 1990, quarterly sampling results showed an increase in contamination (3). In December 1989, a water line break at Boomsnub released over 300,000 gallons of water. The water flushed chromium from the site. A monitor well, MW-4B which is on-site, but downgradient of Boomsnub's plating tanks had 0.17 ppm chromium in October 1989. By January 1990, the level of chromium in MW-4B rose to 749 ppm.
During 1990, Ecology ordered Boomsnub to install a pump and treat system; increase the number of monitor wells; include local off-site private wells in the monitoring program; continue monitoring on-site wells; complete an aquifer test; and pump well MW-4B to keep the chromium plume from reaching other wells in the area (3). Ecology's actions where intended to reduce the off-site migration of chromium while defining the extent of contamination (1). In June 1990, Ecology began to monitor groundwater monthly and between 1990 and 1994 installed forty monitor wells to delineate the plume. An extraction well was installed in January 1991 (1). Presently, 52 groundwater monitor wells have been installed in 28 locations around the site (25).
In April 1990, Boomsnub began to pump and treat groundwater from well MW-4B. Chromium was removed from groundwater by an ion exchange treatment system. At that time, treated water was trucked to the City's Westside Wastewater Treatment Plant since there are no sewers in the area. In May of 1992, Ecology constructed a dedicated 4" pressure line to transport the treated water from Boomsnub to the City's sewer system. The pumping effort could not contain the chromium plume which continued to spread toward the municipal well field.
At the same time, private wells in the immediate vicinity were sampled. Chromium was discovered in five private wells near Boomsnub. During 1991, the chromium in private wells ranged from 0.0112 parts per million (ppm) to 0.292 ppm. In 1993, the well with 0.292 ppm was tested at 0.03 ppm. Another private well over 3,000 feet from the Boomsnub plating facility has had chromium levels of 0.014 ppm. These private wells have been closed and the residences have connected to the available municipal water supplies.
Late in 1990, Ecology found volatile organic compounds (VOCs) on-site at high levels commingled in the chromium plume. The VOCs found included trichloroethylene (TCE), 1,1,1-trichloroethane (TCA), tetrachloroethylene (PCE), and trichlorofluoromethane (Freon 11) (6). By May 1991, Ecology concluded that a source of the VOCs was Airco Gases (Airco) a plant adjacent to Boomsnub (4). Since 1964, Airco had processed liquid nitrogen, oxygen, argon, and other specialty gases at this plant.
In April 1990, the pump and treat operation was started with one on-site well. Chromium is removed from the pumped water by an ion exchange process. In 1993, Ecology expanded the system with nine new wells. In early 1994, Clark Public Utilities added five wells to the system. Late in 1994, EPA drilled two more wells about 3500 feet west of the treatment system at Boomsnub. During December, the extraction system was pumping 75 gallons per minute (30). As of December 1994, the total water processed is about 38.5 million gallons, which removed about 6 tons of chromium. During March and April 1993, an air stripper and an activated carbon unit were added to the groundwater extraction system to remove VOCs (3).
Beside Airco there are other potential sources of VOCs in the site area (Figure 1). A monitor well, MW-8A on the east side of Airco and hydraulically upgradient has detected TCE, TCA, and carbon tetrachloride. North of Boomsnub is a vacant lot which is reported to have been a salvage yard from 1955 until 1978. As late as 1989, debris was present on the property. Automobiles and appliances may have been junked and crushed in the now vacant lot. Boomsnub reported using TCE in the past. Heavy equipment maintenance facilities have been and are in the vicinity. Also, adjacent to Boomsnub is an auto detail shop, a heating and air conditioning repair facility, and a former service station (21).
On January 18, 1994, the Boomsnub/Airco site was proposed for the "Superfund" (2). On May 16, 1994, EPA ordered Boomsnub to stop all plating activities by May 20, unless they could show that such activity would not add to the further releases of chromium. A time extension was granted until May 27, but when sufficient justification for continued operations was not shown, the order went into effect. On June 13, EPA filed a complaint to guarantee access to the facility in order to begin the removal action on June 20. EPA's planned action includes the removal of the plating operations, the plating building, and an estimated 5,000 tons of contaminated soil from beneath the plating building (2) (11).
By December 1994, EPA had excavated a vertical tunnel to 29.5 feet below ground surface. At that depth the water table was encountered. By that time, 54 rail cars of chromium contaminated soils had been removed from the site. The excavation is now being filled in with gravel and an injection gallery is being installed for future possible use to treat waters at a depth of 25 feet below ground surface (30).
On August 16, 1994, Ric Robinson of the Agency for Toxic Substances and Disease Registry (ATSDR), along with Jack Morris and Bob Poss of the Washington Department of Health (WDOH), made a site visit at Boomsnub. Thor Cutler, EPA's On-Scene Coordinator, conducted the tour. Boomsnub workers continue to polish and machine chrome parts in the one remaining building. The rest of Boomsnub's plant is by court order under EPA control. A chain-linked fence surrounds the area and EPA controls entry. EPA has removed the plating building. Mobile buildings have been erected for a command post and a decontamination center. The targeted hot spot is the area beneath the former plating building. During the site visit, two large-tracked shovels were loading truck and trailer rigs with contaminated soil. At a later date, rail cars were used to haul contaminated soil off-site. A vertical tunnel about seventy feet in diameter was being excavated down to groundwater, about thirty feet. At the time of the site visit the tunnel was down about two feet.
Concrete rubble piled to the side of the excavation was stained yellow, which may have been from chromium. Dust control was being accomplished with a water spray. The site surface which is not being excavated is covered with concrete. A pipe structure, which may be part of a drain field, was unearthed during the initial excavation. Adjacent to the south side of the site is a row of ornamental cedar trees about twenty feet high. The trees showed no vegetative stress. Wild blackberries are growing along the west side of the site and they showed no sign of stress. High-volume air monitors were seen on the south and west side of the site. Also, several removal workers were equipped with air monitors.
A series of groundwater extraction wells are in place to the west, off-site. The water is pumped back to the site for treatment. Chromium is removed by ion exchange and VOCs are taken off in a stripping tower. The treated water is discharged to the Vancouver sewer system. The groundwater treatment system will continue for several years depending on the rate of pumping. By December 1994, the extraction well system was extended to about 3500 feet west of the treatment system. By December, the system was treating 75 gallons of water per minute (30).
Hazel Dell has a population of about 15,500. Vancouver, which is adjacent to and south of Hazel Dell, has a population of about 55,450. Nearly 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) (13).
Boomsnub operations included chrome plating, grinding, and metal cutting. It is bordered by a railroad to the west and by light industries and businesses on all sides. Private residences and small businesses are sparsely scattered throughout the area.
Natural Resources Use
Some of the residents adjacent to the site use private wells. These wells are usually completed in the surface aquifer. Six of these private wells have been tested and found to be contaminated with low levels of chromium and/or VOCs. These residents have connected to the available public water supply. In Washington, public wells are defined as wells serving two or more households; private wells serve only one household. The municipal wells in the area are completed in the confined aquifer, the upper Troutdale.
Clark County Public Utility (CPU) supplies the county with water from a well field in the Hazel Dell area. CPU's production wells 5, 7, 16 and 23 are closest to, and directly downgradient from the site. These municipal wells take groundwater from the Upper Troutdale, an aquifer which underlies the contaminated shallow alluvial aquifer. Wells 5, 7, and 23 provide 30 to 40 percent of CPU's municipal water supply. The closest well, Well 7, has not been in operation since 1992. Well 23, which was drilled in 1991, is also currently inoperative. CPU Well 5 is used only for meeting peak demand (29).
Climate and Surface Water
Hazel Dell is in Clark County which has a temperate climate characterized by mild, wet winters and moderately warm, dry summers. The mild climate is a result of the surrounding terrain and proximity to the Pacific Ocean. The Coast Range mountains to the west protect the area from the on shore movement of winter storms, while to the east the Cascade Range and Columbia River Gorge contribute to the area's mild climate. The site is about three miles north of the Columbia River and two miles east of Vancouver Lake. There is no surface water in the immediate vicinity of the site. There is a brook south of Boomsnub, between LaValley and a pallet manufacture. The brook takes storm water and surface water runoff from Airco and possibly other sources. The brook drains to a wetland and sink area. Land surface elevations range from about 290 to less than 240 feet above mean sea level at the site.
Precipitation in the vicinity of the site averages 39 inches annually (7). Most of this total precipitation falls as rain. Snowfall is usually light and remains on the ground two weeks or less. The region has a well-defined wet and dry season, with 75 percent of the precipitation falling in the winter, from October through March (8). During the wet season, the rainfall is generally of light-to-moderate intensity; however rainfall events of two to four inches in 24 hours can occur (9).
Potential evapotranspiration in the vicinity of the site has been estimated to range between 20 and 25 inches annually. Actual evapotranspiration has been estimated to range between 15 and 20 inches annually (8).
The primary supply of public and private potable water for the Vancouver area is the Upper Troutdale aquifer which is about 150 feet below ground surface. Groundwater conditions in the Upper Troutdale are unconfined to semi-confined (29). The rate of flow in the Troutdale ranges from 15 to 200 feet per day (3). The Upper Troutdale underlies an alluvial aquifer which contains the contaminant plume from the site. Pleistocene alluvial deposits form the uppermost aquifer at the site. The alluvial aquifer is unconfined and separated from the Upper Troutdale by a silty, clayey aquitard. Groundwater in the alluvial aquifer flows to the west-northwest (29).
Health outcome data are health data contained in databases such as state tumor registries, birth defects databases, and vital statistics records. Other specific records, such as hospital and medical records and records from site-specific health studies, may be used to evaluate the health of a community living near a site. Using health outcome databases, it may be possible to determine whether the occurrence of certain health outcomes is more frequent than expected in Clark County, Washington.
Health outcome databases include the Washington State Cancer Registry, the Washington State Birth Defect Registry and Vital Statistics databases.
The Washington State Cancer Registry began operation in July 1991 and contracts with two regional tumor registries (Cancer Surveillance System (CSS) and the Blue Mountain Oncology Program [BMOP]) that together cover the entire state. The CSS of the Fred Hutchinson Cancer Research Center provides data on incident cancer cases in Western Washington, covering the majority of the state's population including the largest urban center. This population-based cancer surveillance system includes the incidence and mortality of specific cancers since 1974 for 13 counties. CSS works under contract to the Surveillance, Epidemiology and End Results (SEER) program of the National Cancer Institute. The BMOP covers the remainder of the state. BMOP regularly contacts hospitals in Idaho and Oregon to gather data on Washington residents who seek health care in those states. Cancer data for the area of the state covered by BMOP, including Clark County, is available for 1992.
The Washington Birth Defects Registry is a registry of children with serious birth defects diagnosed before their first birthdays. The database contains information by major birth defect classifications and by demographic factors: county of residence, sex, race, address, and mother's occupation, smoking history, and age. Information is available for the entire state for 1986-1989.
Vital Statistics databases are maintained by the WDOH Center for Health Statistics and include information on live births, fetal deaths, deaths, marriages and divorces for the entire state. Variables included are geographic location (city, county, town), age, sex, race, address, cause of death, birth weight, gestational age, and birth defects.
The results of an investigation of an apparent cluster of childhood cancer in Clark County between 1982 and 1989 were also available. Officials at the Southwest Washington Health District conducted a childhood cancer incidence study of Clark County covering the years of 1963-1985. The study had the following parameters: those children who had a diagnosed malignancy, were aged 14 or younger at the time of diagnosis, and had been a resident of Clark County at the time of diagnosis. The information was obtained from several sources including the Southwest Washington hospital tumor registry, the Oregon Health Sciences tumor registry, the Kaiser Permanente tumor registry in Portland, Oregon, and death certificates for Clark County residents aged 19 and younger who died in Washington and Oregon (ref).
Health outcome data will be evaluated in the Public Health Implications section.
Many newspaper articles have been written about this site. Thirty articles published during 1994 were reviewed. Concerns reported in these articles were media editorials or reports of public concern. More than half of the articles expressed concern about the threat the chromium plume posses to the Clark County water supply. Twelve articles dealt with the possibility of criminal charges against Boomsnub by EPA. Four articles expressed concern for public health and the environment by the relocation of Boomsnub. Eight articles briefly noted the potential human health impacts of chromium. Two of these eight articles were expressions of concern by people who lived near Boomsnub and used the shallow groundwater. The other six articles about health impacts were by EPA or the media.
The Clark County Health District had no person specific health concerns to report. One person interviewed by WDOH was employed seven years ago by a plant adjacent to Boomsnub. While working near Boomsnub that person had acquired allergic symptoms which persist to this time.
On July 20, 1994, Bob Poss of WDOH attended a local public meeting held by the Hazel Dell Neighborhood Association. Community concerns heard at that time included: How much will the cleanup cost and who will pay for it? How come it took so long to discover the contamination and to do something about it? What will be done with the contaminated waste, where will it go, could it be recycled? Who will monitor the new Boomsnub facility?