PUBLIC HEALTH ASSESSMENT
MCCHORD AIR FORCE BASE
PIERCE COUNTY, TACOMA, WASHINGTON
Area E
Sites 10, 49, 50, 51, and 56
Background
Area E encompasses the southern third of industrial and operational activities at McCAFB. The environmental contamination at Area E is largely associated with aircraft maintenance and flight operations. Most of Area E has a cement cover; grassy areas also exist. Currently, storm runoff drains into Clover Creek after passing through industrial separating units (Wastewater C Study). Environmental stress (dead grass resulting from spills near one of the buildings) was reported (CH2M 1982) in the IRP Records Search (1982). Drainage of industrial waste runoff into Clover Creek was untreated until 1948. Figure 3, Appendix A, shows the site locations; Table B-19 lists information about the types of wastes disposed or spilled at Area E.
Table B-19. Waste History at Area E
| Site | Site Description | Wastes | Disposal/ Spill Dates |
| 10 | Landfill north of Bldg. 304 | Industrial, domestic, and construction wastes | 1950s-1966 |
| 49 | Liquid spill area south of Bldg. 392 | Waste fuels, POLs, and solvents | 1978 |
| 50 | Liquid spill area west of 6th Street | Waste fuels, including large quantities of JP-4, POL, and solvents; 2,000- gallon spill in 1981, not known if contained | 1962-1980 |
| 51 | Liquid spill area, drainage ditch west of 6th Street | Waste fuels, POL, paints, and solvents | Unknown |
| 56 | Septic tank system | Possible herbicide and pesticide residues | Pre-1948 |
Because groundwater flows northwest, and Area E lies in the southeastern part of the base, Area E is therefore upgradient of most of the identified contaminant sources on McCAFB. Only Area I, Sites 13 and 22, are upgradient of Area E.
Environmental Contamination
Groundwater
Groundwater contamination at Area E has been investigated during three different studies. Analytical data for the most recent study are summarized in Table B-20.
During the IRP Phase II, Stage 1 investigation, five monitoring wells were installed that were completed in the surficial aquifer (maximum depth 78 feet). The main text of this public health assessment contains additional information about the Phase II, Stage I Study.
During Stage 2 of the Phase II investigations, no additional monitoring wells were built in Area E. Water samples from the wells installed during the Stage 1 investigations were analyzed for contaminants. The main text of this public health assessment contains additional information about the Phase II, Stage 2 Study.
The Phase II groundwater data are not included in Table B-20, because the reports indicate the data may be compromised due to improperly constructed wells and laboratory contamination.
Eight new monitoring wells were installed during the site investigation of Area E in 1990 and 1991. Four monitoring wells were installed upgradient of the suspected sources of contamination, and four wells were installed downgradient. Groundwater samples were taken from eight of the new wells and from three of the five existing wells.
Forty-four groundwater samples were collected during sampling rounds conducted quarterly from June 1990 to May 1991. All groundwater samples collected were analyzed for VOCs and metals. Both filtered and unfiltered groundwater samples were collected and analyzed for inorganic compounds. Only unfiltered results are included in the data tables.
Analytical data for the most recent investigation at Area E are summarized in Table B-20.
Table B-20. Contaminant Concentration in On-Base Groundwater - Area E
| Contaminant | Maximum Concentration (ppb) |
Date | Reference |
Comparison Value | |
| (ppb) | Source | ||||
| 1,1-Dichloroethylene | 0.85 | 7/90 | SI | 0.06 | CREG |
| Antimony | 11 | 9/90 | SI | 4 | RMEG-Child |
| Arsenic | 14 | 9/90 | SI | 0.02 | CREG |
| Lead | 40 | 9/90 | SI | None | EPA-Carcinogen |
| Vanadium | 93 | 9/90 | SI | 20 | LTHA |
Sites in Areas F and H and Other Sites of Current or Former
Fire Training Areas on Eastern Boundary of Base
Sites 30 and 31 in Area F
Site 27 in Area H
Other Sites 28, 29, and 32
Background
Six fire training areas are included in this group of sites (Sites 27, 28, 29, 30, 31, 32). None of these areas are currently in use. The most recently used site (Site 32) has not been used since July 1990. Site 32 has a clay liner, but, under current EPA standards, an impermeable liner is required. All except one of the fire training areas are on the eastern boundary of McCAFB. One former fire training area is included in Area C (Site 33) because of geographic location. Figure 3, Appendix A, shows the locations of the sites; Table B-21 lists information about the types of wastes disposed or spilled at the areas.
Table B-21. Waste History of Fire Training Areas on the Eastern Boundary of the Base
| Site | Site Description | Wastes | Disposal/ Spill Dates |
| 27 | Former Fire Training Area | Waste fuels, JP-4, and AVGAS; 24 exercises per year using about 300 gallons of fuel for each exercise; no soil liner | 1960-1977 |
| 28 | Former Fire Training Area | Waste fuels, such as JP-4; used for helicopter fire training; 50 training exercises per year using about 100 gallons of fuel per exercise | 1962 |
| 29 | Former Crash Fire Training Area (Shown on base maps, but no other information) | Unknown; base maps list area as a fire training area but no reports of such activity at this location were made during the IRP Phase I Record Search; no visible signs of a fire training area at this location | Never Active |
| 30 | Former Fire Fighter Training Area | Solvents, alcohol, AVGAS, and oils were burned during training exercises; 35 exercises per year using about 300 gallons of fuel per exercise; no soil liner | 1955-1960 |
| 31 | Former Fire Fighter Training Area | Solvents, alcohol, AVGAS, and oils were burned during training exercises; 35 exercises per year using about 300 gallons of fuel each; no soil liner | 1950-1955 |
| 32 | Most Recent Fire Fighter Training Area | Waste fuel (JP-4); 10 exercises per year using 300 to 400 gallons of fuel per exercise; clay liner in place; exercises will not be conducted again until impermeable liner is installed. | 1976-1990 |
Environmental Contamination
Groundwater
Groundwater contamination at the eastern boundary of the base was investigated during both stages of the IRP Phase II Study. During the IRP Phase II, Stage 1 investigations, one monitoring well was installed at Area F that was completed in the surficial aquifer. The main text of this public health assessment contains additional information about the Phase II, Stage 1 Study.
During Stage 2 of Phase II, one additional monitoring well was built at the northeastern corner of McCAFB at Area H (Site 27). The main text of this public health assessment contains additional information about the Phase II, Stage 2 Study. Because the Phase II data was reported to be compromised due to improper well construction and laboratory contamination, concentrations of groundwater contaminants exceeding comparison values are not included here. VOCs and metals were detected during both Phase II studies at levels exceeding the comparison values.
During site hazard assessment, one well was installed downgradient at Site 27. The groundwater was sampled and analyzed for total petroleum hydrocarbons and for benzene, toluene, ethyl benzene, and xylene (BTEX). No contaminants were detected.
Subsurface soil
As part of the long-term monitoring program, confirmation subsurface soil sampling was conducted at Sites 30 and 31 in March 1993. One sample was collected from Site 30 and duplicates at Site 31 at a depth of about 10 feet. The samples were analyzed for VOCs, semi-volatile organic compounds, diesel, and priority pollutant metals. No contaminants at Site 30 exceeded comparison values. Refer to Table B-22 for a summary of organic contaminants at Site 31 either exceeding comparison values or else for which comparison values are not available. The concentration of arsenic in all the samples (2.5-4.8 ppm) exceeded the comparison value (0.4 ppm, CREG). The maximum concentration for lead was 34 ppm; no comparison value is available for lead.
Table B-22. Organic Contaminant Concentration in On-Base Subsurface Soil - Site 31,
Area F/H
| Contaminant | Maximum Concentration (ppb) |
Date | Reference |
Comparison Value | |
| (ppb) | Source | ||||
| Benzo(a)pyrene | 2.3 | 1993 | Ebasco, Long-Term Monitoring Program | 0.1 | CREG |
| Total Carcinogenic PAHs | 12.2 | 1993 | Ebasco, Long-Term Monitoring Program | None | Carcinogen |
Subsurface soil was analyzed for contaminants at three of the former Fire Training Areas during site hazard assessment in 1993. At Sites 27 and 32, fuel-contaminated soil was identified during the initial test pit investigations. Approximately 6,000 yards of soil were removed at each location; the dimensions of the excavation at Site 27 were approximately 160 by 220 ft with a depth of 6.5 ft, the dimensions of the excavation at Site 32 were approximately 200 by 200 ft with a depth of 7 ft. Four samples before and after the remediation were collected analyzed for total petroleum hydrocarbon compounds and for BTEX at Site 27; three samples before and nine after the remediation at Site 32 were collected and analyzed for total petroleum hydrocarbon compounds. No detections exceeded the comparison values.
A release from an underground storage tank discovered during the excavation of Site 32 occurred. The tank was also removed and the area beneath the tank was excavated to a depth of about 29 ft below ground surface to remove the contaminated soils. A confirmation sample was collected from the bottom of the excavation area directly beneath the tank.
At Site 28, three test pits were excavated to a depth of 5 ft. One soil sample was collected from the base of each test pit and analyzed for total petroleum hydrocarbon compounds. No detections exceeded comparison values.
Area G
Site 44
Background
Area G includes only one site (Site 44), which is the motor pool leach pits in the vehicle maintenance area. Reports during the IRP Phase I Records Search indicated that large quantities of oil were spilled around the diesel tanks. Floor drains in Building 779 discharged into two dry wells. No environmental sampling had been conducted in Area G, until site hazard assessment began in January 1993. Figure 3, Appendix A, shows the location of the site; Table B-23 lists information about the types of wastes disposed or spilled at Area G.
Table B-23. Waste History - Area G
| Site | Site Description | Wastes | Disposal/ Spill Dates |
| 44 | Motor pool leach pits, disposal/spill site | Waste fuels, POL, and solvents | Unknown |
Environmental Contamination
Groundwater
During site hazard assessment, three groundwater monitoring wells (depths: 25-29 ft) were installed at Site 44, one downgradient, one upgradient, and one within the source area. Two months later two additional monitoring wells (depths: 35-45 ft) were installed near the South Base Well and one (depth: 27 ft) near the North Base Well. Groundwater samples were collected in March 1993 from the first set of wells installed; and in May 1993 from the second set of wells installed. All samples were analyzed for total petroleum hydrocarbon compounds and volatile and semivolatile organic compounds. The concentrations of groundwater contaminants exceeding comparison values during the two 1993 sampling events are summarized in Table B-24.
Table B-24. Contaminant Concentrations in On-Base Groundwater Monitoring Wells - Area G, Site 44
| Groundwater Contaminants | Range of Levels (ppb) |
Date | Reference | Comparison Value | |
| (ppb) | Source | ||||
| Benzene | 97-110 1.4-2 (Near South Base Well) ND (Near North Base Well) |
March 1993 May 1993 May 1993 |
EBASCO EBASCO EBASCO |
1 | CREG |
| Ethylbenzene | 1100-1200 | March 1993 | EBASCO | 1000 | Child RMEG |
| Naphthalene | 29-140 | March 1993 | EBASCO | 20 | LTHA |
| Lead (total) | 5.6-38.1 | March 1993 | EBASCO | None | Carcinogen |
| Lead (filtered) | 16.8-17.4 | March 1993 | EBASCO | None | Carcinogen |
Area I
Sites 13 and 22
Background
Area I includes Site 13, an inactive general landfill, and Site 22, a burial site; both are on the eastern margin of McCAFB. Interviews with base personnel about Site 13 have indicated that approximately 50 drums of liquid waste were disposed in a trench that was dug to a depth of approximately 40 feet below the present grade. Subsequent landfill activities have deposited general construction debris across the entire landfill area. The removal and waste characterization of the drums is described in the SI report. Figure 3 shows the locations of the sites; Table B-25 lists information about the types of wastes disposed or spilled at Area I.
Table B-25. Waste History at Area I
| Site | Site Description | Wastes | Disposal/ Spill Dates |
| 13 | General landfill | Domestic and construction waste; 50 drums of liquid waste, including paints and solvents; open burning took place in 1950s | 1950-1979 |
| 22 | Burial site | Cars and heavy equipment; waste POL | 1939-1951 |
The Area I landfill site is on a flat to gently rolling part of the Tacoma upland. The site has been graded to a level, sparsely vegetated, surface. Land use in the immediate vicinity of the site includes a runway more than 1,000 feet to the west, runway support facilities 600 feet to the north, and a family camping area about 1500 feet to the south. There are no continuously flowing drainage channels in Area I, largely because of the high infiltration rates in the soil and the flat topography. The closest stream is Morey Creek, which is about 2000 feet north of the landfill. Some low-lying marshland is about 400 feet southeast of the site. A large lake (Spanaway Lake) is about 1.5 miles southeast of the site. An off-base residential area is immediately adjacent to the base, about 1500 feet east of the landfill. The closest downgradient potable water wells are more than a mile away.
Environmental Contamination
From historic records and visual observations, contaminants detected at the site are believed to have originated from waste disposal in the unlined landfill. A coarse, permeable gravel underlies the landfill, and there are no significant barriers to groundwater or contaminant movement between the landfill and the underlying unconfined aquifer. The approximate limits of the landfill trench were defined, and the suspected location of the buried drums within the trench was identified during the site investigation (EBASCO Environmental 1991d).
Sampling and analysis of media in Area I were not performed during either the Stage 1 or Stage 2 Phase II investigations. During the site investigation, 10 groundwater wells and two double soil gas migration probes were installed on the boundaries of the landfill. A soil gas survey, geophysical surveys, and three source area borings also were conducted at the landfill.
Groundwater
Groundwater flows northeast below McCAFB; Site 13 lies on the eastern boundary of the base. Site 13 is thus upgradient of all other suspected sources of contamination on the base, including Area I, Site 22, and Area E. Three of the monitoring wells were installed in a cluster upgradient of the area; seven were installed in three clusters downgradient. The downgradient wells consist of three well pairs drilled to between 40 and 60 feet and one deeper well about 100 feet deep completed in the first aquifer. The upgradient wells consist of one well pair and a deep well; the three wells are drilled to depths similar to those of the downgradient wells.
Between June 1990 and May 1991, groundwater samples were collected quarterly from the 10 monitoring wells. The downgradient wells were sampled twice; the upgradient wells were sampled four times. Each sample was analyzed for metals and VOCs. Contaminant concentrations are listed in Table B-26.
Table B-26. Contaminant Concentrations in On-base Groundwater Monitoring Wells - Area I
| Contaminant | Range of Levels (ppb) |
Date | Reference | Comparison Value | |
| (ppb) | Source | ||||
| Arsenic | 3.2-7.5 | 6/90- 5/91 |
EBASCO SI Report |
0.02 | CREG |
| Cadmium | 6 - 8 | 6/90- 5/91 |
EBASCO SI Report |
2 | EMEG- Child |
| Lead | 7.6-29 | 6/90- 5/91 |
EBASCO SI Report |
None | EPA-Carcinogen |
| Chloromethane | 0.3-11 | 6/90- 5/91 |
EBASCO SI Report |
3 | LTHA |
| Manganese | 9-3800 | 6/90- 5/91 |
EBASCO SI Report |
50 | RMEG- Child |
| Vinyl Chloride | 0.8-3.1 | 6/90- 5/91 |
EBASCO SI Report |
0.2 | EMEG- Child |
Soil Gas Investigations
Ninety-five soil gas samples were analyzed during the soil gas survey. Each sample was analyzed with an explosimeter and an organic vapor analyzer while it was being collected. The samples were then analyzed with a portable gas chromatograph for VOCs. Most of the samples exceeded the lower explosive limit. Most of the sample locations also contained more than 1000 ppm organic vapor.
During this study, two sets of double soil gas migration probes were installed at depths of about 15 and 25 feet to monitor levels of methane and other volatile organic compounds. Gas migration probe sampling took place in March 1991 and August 1991. Methane concentrations did not exceed the state landfilling standards (50,000 ppm) for migrating gas at the site boundary.
The soil gas survey indicates that some organic vapors underlie most of the cleared area of the site, with rapidly diminishing values observed near or just inside the surrounding woods. Most of the organic vapor was reported to be methane, but other VOCs were detected at the central part of the site, as well as near the base boundary. Airborne contaminants are greatly diluted and are below detection limits.
Subsurface Soil
Three soil borings were drilled through the suspected landfill location at Area I. Three soil samples were collected from each boring, including one sample at the surface to a depth of six inches and other samples at a depth of up to 24.5 feet. The soil analyses indicated that the soils and waste in the landfill are not generally regulated hazardous wastes according to RCRA and Washington State Dangerous Waste regulations (EBASCO Environmental 1991d).
Low levels of volatile organic contamination were detected in all of the source area soil samples. No VOCs or heavy metal contamination, except arsenic, exceeded corresponding comparison values.
The concentrations of lead at McCAFB are included in Table B-27 because comparison values are not currently available. The concentration of lead in the soil at McCAFB is similar to background concentrations found in other soil in the western United States (ATSDR 1992f).
Table B-27. Range of Contaminant Concentrations in On-Base Soil Samples - Area I
| Contaminant | Range of Levels (ppm) |
Depth Inches |
Date | Reference | Comparison Value | |
| (ppm) | Source | |||||
| Arsenic | 2.8 - 5.7 | 6 inches to 24.5 feet |
1990 | EBASCO SI Report |
0.02 | CREG |
| Lead | 2.6 - 43 | 6 inches to 24.5 feet |
1990 | EBASCO SI Report |
None | EPA-Carcinogen |
Area J
Sites 36 and 48
Background
Area J consists of Sites 36 and 48; both are in the base civil engineering yard. Site 36 consists of a storm drain ditch originating near Building 540 and extending east beyond the fence line of the civil engineering yard. Site 48 includes an aboveground pentachlorophenol (PCP) wood preservative tank and the soil around it that has become contaminated with spilled PCP. Figure 3, Appendix A, shows the site locations; Table B-28 lists the information about the types of wastes disposed or spilled at Area J.
Table B-28 Waste History at Area J
| Site | Site Description | Wastes | Disposal/ Spill Dates |
| 36 | Storm drain ditch | Waste paint, oil, and fuel | Unknown |
| 48 | Pentachlorophenol wood preservative tank | Pentachlorophenol overflow and spills | 1950s-? |
Surface runoff from the civil engineering yard and the shop areas, including the entomology shop, drains into the storm water ditch (Site 36). Unidentified quantities of waste materials have drained into the ditch. Migration of the wastes into the groundwater is possible. No environmental sampling had been conducted at Site 36 until 1993.
Unknown quantities of PCP have been spilled at Site 48 since the 1950s. Migration of the PCP into the groundwater by infiltration is possible. Contamination at Area J was not investigated until 1993; however, the IRP Phase I Records Search reported that the PCP content of the soil beneath the tank was less than 69 ppm.
Environmental Contamination
Subsurface Soil
As part of the long-term monitoring program, confirmation subsurface soil sampling was conducted at the two sites in March 1993. Duplicate samples were collected from Site 36 at a depth of 10 feet and five samples plus one duplicate at Site 48 at a depth of about two feet. The samples from Site 36 were analyzed for VOCs, semi-volatile organic compounds, pesticides/PCBs, total petroleum hydrocarbons, gasoline, diesel, and priority pollutant metals. The samples from Site 48 were analyzed for semi-volatile organic compounds, and priority pollutant metals. Refer to Table B-29 for a summary of organic contaminants at the two sites either exceeding comparison values or else for which comparison values are not available. The concentration of arsenic in all the samples (1.9-4.4 ppm) exceeded the comparison value (0.4 ppm, CREG). The maximum concentration for lead was 105 ppm; no comparison value is available for lead.
Table B-29. Organic Contaminant Concentration in On-Base Subsurface Soil - Sites 36 and 48, Area J
| Contaminant | Maximum Concentration (ppb) |
Date | Reference |
Comparison Value | |
| (ppb) | Source | ||||
| Site 36-Benzo(a)pyrene | 0.4 | 1993 | Ebasco, Long-Term Monitoring Program | 0.1 | CREG |
| Site 36-Total Carcinogenic PAHs | 2.4 | 1993 | Ebasco, Long-Term Monitoring Program | None | Carcinogen |
| Site 48-2-Methylnaphthalene | 12.0 | 1993 | Ebasco, Long-Term Monitoring Program | None | Non-carcinogen |
| Site 48-Pentachlorophenol | 6.2 | 1993 | Ebasco, Long-Term Monitoring Program | 2 | Pica-child EMEG |
| Site 48-Total Carcinogenic PAHs | 0.03 | 1993 | Ebasco, Long-Term Monitoring Program | None | Carcinogen |
Unspecified Locations
Sites 3, 8, 9, 11, 14-21, 23-25, 43, 59, 63, 64, and 65
Background
All of the sites listed in this section, except Sites 64 and 65, have been recommended by McChord AFB for "no further action" in accordance with the 1989 "Air Force IRP Management Guidance." Table B-30 lists the waste history of those sites. Hazardous materials were not disposed or spilled at Sites 8, 9, 11, 14, 15, 19, 20, 21, 23, and 24.
Table B-30. Waste History of Sites - Unspecified Locations
| Site | Site Description | Wastes | Disposal/ Spill Dates |
| 3 | Burial site | Low-level radioactive waste | 1950s |
| 8 | Burial site | Coal ash | 1950s |
| 9 | Burial site | Fire brick and hardwood flooring | Unknown |
| 11 | Landfill | Demolition and construction debris | Until 1970 |
| 14 | Burial site | Demolition and construction debris | 1972-1973 |
| 15 | Unauthorized surface dump | Domestic wastes | 1960-1972 |
| 16 | Burial site | Miscellaneous automotive and aircraft equipment | 1940s-? |
| 17 | Burial site | Demolition debris; small amount industrial wastes | 1950s |
| 18 | Burial site (dry well) | Caustic soda | Until 1970s |
| 19 | Burial site | Domestic and demolition debris | 1952-1965 |
| 20 | Burial site | Domestic and demolition debris | ? |
| 21 | Burial site | Demolition and construction debris | ? |
| 23 | Landfill | Demolition and construction debris | Unknown |
| 24 | Dump | Flight line sweepings (loose, natural objects, such as rocks and vegetation) | 1957-1960 |
| 25 | Surface Dump | Flight line sweepings, chemicals to remove runway rubber deposits, including cresylic acid, benzene, and phenolic compounds | 1950s-1970 |
| 43 | Liquid waste disposal site | POL for weed control | Until 1960s |
| 59 | Fuel oil spill | Fuel oil (1000 gallons) | 1960s |
| 63 | Remediated POL soil contamination in two areas | POL; contaminated soils removed in 1988 | 1984 |
| 64 | Entomology shop dry well | Small quantities of entomology wastes: rinsates of pesticides | ? |
| 65 | Underground storage tanks - 22 at 7 different locations | Includes tanks eligible for the Defense Environmental Restoration Program; removal of tanks is planned; information about any leakage/ environmental contamination will not be available until 1994. | Unknown |
Figure 3, Appendix A, shows the site locations. Environmental sampling has been conducted only at Sites 63 and 64. Additional information is included for those sites at which hazardous materials were either spilled or disposed because they have been proposed for no further action.
Site 3: Low-Level Radioactive Burial Site
Site 3 is within a 15-square-foot fenced and posted enclosure in the center of the 97-acre fenced, secured, and guarded munitions storage area north of the golf course. During the 1950s, small quantities of discarded, low-level radioactive radar instrument components (e.g., krypton tubes, fluorescent dials and signs painted with radium, and strontium-containing materials) were stored in a 5-foot-cube, pre-cast concrete utility vault. Sometime before 1959, the vault was filled with concrete and buried under 4 feet of soil at its present location.
In 1978, the site was partially excavated by Disaster Preparedness to confirm the existence and condition of the buried vault. The vault was found to have no discoloration or defects in its surfaces; detectors monitored no emissions above background levels. The vault was subsequently reburied.
Site 16: Automotive Equipment and Aircraft Parts Burial
Site 16 is believed to be beneath the baseball field north of the 1100 dormitories and east of the railroad on a large open lawn. Structural components of aircraft and automobiles are reported to be buried there. This salvage yard was used from the early to mid-1940s, when the area was covered with clean soil and planted with grass. The baseball field was built in 1967.
Site 17: Motor Pool Building Demolition and Burial
Site 17, which is believed to be in a large, open lawn 400 feet south of Clover Creek between Buildings 1110 and 1120, was the location of a small-operation motor pool. In the early 1950s, the building was cleaned out, demolished, and buried where it stood. The area is currently a cultivated grass field.
Site 18: Caustic Soda Pit
Site 18 is believed to be on the flight line infield 100-200 feet east of "J" Ramp. The area is adjacent to buildings, the runup pad, and aircraft parking. Only one report during the IRP Phase I Records Search referred to this area, which may have been a dry well disposal site for spent, "hot tank" cleaning solutions. It was reported to have been closed in the mid-1970s and allowed to revegetate naturally.
Site 25: Flight Line Sweepings Surface Dump
Site 25 is believed to be between Buildings 328 and 348 south of Lincoln Boulevard at the southwestern end of a taxiway in a slight depression. Flight line sweepings and runway rubber deposits were disposed of on the surface of the depression between the 1950s and 1970. In 1964, the Air Force began regular maintenance (rubber removal) on runways. Chemicals with a base of cresylic acid and a blend of benzene and synthetic surfactants were used to remove rubber buildup on concrete pavements. Alkaline phenolic chemicals were used on asphalt pavements. In the late 1960s, environmental regulations required that runways be bermed to prevent runoff and that the sweepings be drained to collect the solvents for disposal. The use of chemicals stopped after the mid- 1960s. The annual cleaning of touchdown areas was performed three or four times after 1964. This site is adjacent to two areas of potentially hazardous waste fuel, petroleum, oil, lubricants, and solvent releases (Sites 49 and 50).
Site 43: Petroleum, Oil, Lubricants Disposal
Site 43 is believed to be 800 feet north of the Perimeter Road, east of Fort Lewis, and adjacent to the 350 ammunitions area compound. Only one interview source during the Phase I Records Search referred to this disposal site. Waste petroleum, oil, and lubricants occasionally may have been spread on the ground for weed control. In the 1960s, mowing replaced the use wastes for weed control adjacent to ammunition areas.
Site 59: 1000 Gallon Fuel Oil Spill
This site is believed to be under the parking lot the west of Building 675, 300 feet east of the railroad. Only one interview source during the Phase I Records Search referred to this fuel oil spill, which took place over a 48-hour period sometime during the 1960s. In the late 1960s, Building 675 was remodeled, and the paved parking lot expanded.
Site 63: Remediated Soil Areas
This site consists of one area adjacent to Building 792 and another area northeast of Building 1173. The Washington Department of Ecology noted surface staining in the two areas during a routine inspection of McChord AFB in 1984. The results of an investigation that included soil borings and laboratory analysis of soil samples in the two areas was published in May 1986 (Report of Geotechnical/Environmental Investigation, Hydrocarbon Contamination of Buildings 792 and 1173, McChord AFB). The results of another investigation were published in January 1987 (Results of Supplemental Sampling and Analysis, Soil Samples Near Buildings No. 792 and 1173). That investigation described the finding of TPHs, VOCs, PAHs, halogenated hydrocarbons, total metals, and tricresyl phosphate in soil samples collected from excavated test pits. Remediation of the relatively small areas of contaminated soils was completed in 1988. The remediation process is described in the Site Description and History section of the main text of this public health assessment.
Site 64: Entomology Shop Drywell
During site hazard assessment at Site 64, the Entomology Shop Drywell, all soil was removed for disposal within the drywell and to a depth of about 6 to 7 feet. One soil sample was collected from the base of the excavation and analyzed for pesticides and polychlorinated biphenyls (PCBs). Contaminants that were detected at concentrations exceeding comparison values are summarized in Table B-31.
Table B-31. Range of Contaminant Concentrations in On-base Subsurface Soil Samples - Site 64
| Contaminant | Range of Levels (ppm) |
Depth | Date | Reference | Comparison Value | |
| (ppm) | Source | |||||
| alpha-Chlordane | 90* | about 7 feet | 1993 | EBASCO | 0.5 | CREG |
| gamma-Chlordane | 94* | about 7 feet | 1993 | EBASCO | 0.5 | CREG |
The one groundwater monitor well (depth: 25 feet) that was installed downgradient during site hazard assessment had no measurable water during the May 1993 sampling event; therefore no groundwater samples were collected.
Site 65: Underground Storage Tanks
This site includes tanks eligible for the Defense Environmental Restoration Program. Removal
of all underground storage tanks is planned. Confirmational soil samples are being collected as
tanks are removed to determine if there has been any leakage or environmental contamination. A
report about this removal program will be available in 1994.
Toxicologic Summaries
Toxicologic Summary for
Trichloroethylene
Trichloroethylene (TCE) is a clear, colorless, nonflammable liquid that has a sweet odor. The agent can be smelled at concentrations of approximately 20 to 80 ppm. Some workers may not be able to smell TCE at concentrations near the permissible workplace exposure limit of 50 ppm; therefore, relying on employees' sense of smell may not provide adequate warning of its presence (ATSDR 1992a).
Trichloroethylene is a volatile organic compound (VOC) also known as trichloroethene. TCE does not occur naturally in the environment; therefore, its presence indicates manufacture, use, or storage of the chemical. TCE is used extensively for vapor degreasing of fabricated metal parts. Consumer products containing TCE include typewriter correction fluids, paint removers and strippers, cosmetics, adhesives, spot removers, and rug-cleaning fluids. In the workplace, TCE is seldom used in pure form. Industrial-grade TCE contains small amounts of stabilizers in the form of antioxidants or acid receptors. Total chemical impurities usually do not exceed 0.1% by weight (ATSDR 1992a).
Because of its widespread use, TCE has become a common environmental contaminant. Contamination results from evaporative losses during use; discharge to surface waters and groundwater by industry, commerce, and individual consumers; and leaching from hazardous waste landfills into groundwater. In the atmosphere, TCE is destroyed by photooxidation; it has a half-life of less than seven days. That relatively short half-life significantly limits the transport of TCE in air. On the other hand, the continual volatilization of TCE from emission sources or contaminated surface waters ensures its persistence in air. TCE in drinking water is a result of its rapid leaching from landfills and its discharge from industrial wastewaters. TCE volatilizes quickly from water depending on temperature, water movement, and aeration. The biodegradation of TCE under anaerobic conditions is slow; therefore, TCE is relatively persistent in subsurface waters (ATSDR 1992a).
TCE is one of the VOCs most frequently found in groundwater. Because TCE is volatile, household activities such as bathing, laundering, and cooking with TCE-contaminated water may produce air concentrations above ambient levels. Questions about an association between ingested TCE and long-term health effects, including malignancies, have been raised, but scientific evidence that the effects are caused by TCE exposure is lacking (ATSDR 1992b).
Compared with dermal absorption, pulmonary and gastrointestinal absorption of TCE is rapid. Absorption of TCE vapor through the skin is negligible (ATSDR 1992a). Once absorbed, TCE is rapidly cleared from the blood. Because of its lipid solubility, TCE accumulates in organs containing high levels of adipose (fat) tissue. Data from animal studies indicate that body fat, adrenal glands, ovaries, and cellular components of the blood accumulate the greatest portion of absorbed TCE. TCE rapidly crosses the placenta in both people and animals and can accumulate in the fetus (ATSDR 1992a).
In people, TCE is metabolized primarily in the liver by the mixed function oxidase system, which probably converts TCE to an oxide (epoxide). Subsequently, this reactive intermediate may rearrange to form trichloroacetaldehyde and then chloral hydrate. The latter forms the trichloroethanol and trichloroacetic acid metabolites excreted in the urine after TCE exposure (ATSDR 1992b).
A relatively small amount of absorbed TCE is exhaled unchanged; most of an absorbed dose is metabolized and excreted in the urine. After exposure to air concentrations between 100 and 200 ppm, approximately 30% to 50% of an absorbed dose appears in urine as trichloroethanol, and about 10% to 30% appears as trichloroacetic acid. The time between TCE inhalation and urinary excretion of trichloroethanol is relatively short (approximately 10 hours). Urinary excretion of trichloroacetic acid takes longer (approximately 52 hours). Trichloroacetic acid is theoretically detectable in urine for at least a week after TCE exposure (ATSDR (1992a).
TCE-induced central nervous system symptoms depend on both concentration and exposure duration. In one study of human volunteers, exposure to TCE air levels of 27 ppm for four hours caused drowsiness and mucous membrane irritation; exposure to TCE at 81 ppm caused headaches. In another study, volunteers reported drowsiness, lethargy, and nausea within five minutes of exposures to anesthetic concentrations of 2,000 ppm. TCE presumably anesthetizes by affecting cell membranes and altering neuronal transmission. Symptoms resulting from short-term exposures (a few hours) typically resolve within a few hours. Workers exposed to TCE during industrial cleaning and degreasing operations complained of decreased appetite, sleep disturbances, ataxia, vertigo, headache, and short-term memory loss (ATSDR 1992a).
Mortality studies of TCE-exposed workers do not indicate an increased risk of cardiovascular death. A few susceptible people exposed to near anesthetic levels (200 ppm) during vigorous activity, may have an increased risk of cardiac dysrhythmia. However, ventricular ectopy would not be expected from TCE exposure at background environmental levels, or at those currently allowed in the workplace (ATSDR 1992a).
When swallowed, TCE causes gastrointestinal irritation and possible inflammation of the gastrointestinal tract manifested as nausea, vomiting, diarrhea, and abdominal pain (ATSDR 1992a).
No increased incidence of congenital malformation has been observed in babies born to mothers occupationally exposed to TCE. A small cross-sectional study of TCE-exposed degreasing workers showed no effect on male germ cells. Data from animal studies reveal no adverse effects on reproductive system histology, fertility, or other reproductive performance parameters (ATSDR 1992a).
Inhalation or oral exposure to high doses of TCE results in liver and lung tumors in mice, and results in renal adenocarcinomas, testicular tumors, and, possibly, leukemia in rats. The liver tumor data obtained from the mice studies is controversial because the mouse species studied tends to spontaneously form liver tumors. The presence of TCE stabilizers, such as epichlorohydrin, also may confound some of the results. Studies to date indicate that mice are more susceptible than rats to TCE carcinogenicity (ATSDR 1992a).
Most early epidemiologic studies of workplace exposures to TCE did not demonstrate a significant increase in the incidence of cancer. A recent follow-up study of workers, however, found excesses of bladder cancer and lymphomas. The significance of the study has yet to be confirmed. Some inconsistencies between results of animal and human studies may be caused by metabolic saturation and formation of reactive intermediates in animals exposed to high TCE levels; the same results have not been seen in people with low-level exposure (ATSDR 1992a).
EPA considers the weight of evidence sufficient to conclude that TCE is carcinogenic in animals and is probably carcinogenic in people. However, findings of animal studies to date do not meet the National Toxicology Program (NTP) criteria on carcinogenicity in both sexes of multiple species. Therefore, NTP does not consider TCE a carcinogen (ATSDR 1992a).
TCE produces minimal irritation of the respiratory tract, except at concentrations exceeding
current workplace standards. TCE and other solvents may produce contact dermatitis, rashes,
and burns. The defatting dermatitis that may result from prolonged contact can reduce resistance
to skin infections. No deleterious effects on the immune system have been noted in people
exposed to TCE from environmental sources. Immunologic studies in animals are inconclusive
(ATSDR 1992a).
REFERENCES
Agency for Toxic Substances and Disease Registry. 1992. Toxicological Profile for Trichloroethylene.
Agency for Toxic Substances and Disease Registry. 1992. Case Study in Environmental
Medicine for Trichloroethylene.
Toxicologic Summary for
1,2-dichloroethylene
1,2-dichloroethylene (DCE), also known as 1,2-dichloroethene, is a highly flammable, colorless liquid with a sharp, harsh odor. People can smell DCE at air concentrations of approximately 17 ppm. 1,2-DCE exists in two forms: cis-1,2-DCE and trans-1,2-DCE. Both forms may be present in a mixture. DCE is used primarily as a chemical intermediate in the synthesis of chlorinated solvents and compounds. It also has been used as a lot-temperature extraction solvent for organic materials such as dyes, perfumes, and lacquers.
DCE's presence in the environment is caused entirely by human activity. DCE is released into the environment from factories that make or use the chemical; from landfills and hazardous waste sites; from chemical spills; and from burning of vinyl-containing objects.
DCE is removed from the atmosphere chiefly by reaction with photochemically generated hydroxyl radicals. The estimated half-lives for cis- and trans- isomers are 8.3 and 3.6 days, respectively. Precipitation also may remove DCE from the atmosphere; however, most DCE that dissipates in that way probably reenters the atmosphere by volatilization. When released to surface water, most DCE volatilizes; in a model river, its half-life is estimated to be approximately three to six hours. When released to soil, DCE volatilizes rapidly from moist soil surfaces and leaches through subsurface soil, potentially becoming a groundwater contaminant. In groundwater, DCE is susceptible to anaerobic biodegradation. Experimental data indicate that the anaerobic biodegradation half-life of DCE in groundwater is approximately 13-48 weeks.
The hepatic microsomal cytochrome P-450 enzyme system catalyzes the first step of metabolism of DCE. The ethylene double bonds undergo epoxidation to form dichlorinated epoxides. The dichlorinated epoxides in turn can undergo a nonenzymatic rearrangement to form dichloroacetaldehyde, the predominant metabolite of microsomal cytochrome P-450 activity. The dichloroacetaldehyde is extensively converted to dichloroethanol and dichloroacetate by cytosolic or mitochondrial aldehyde and alcohol dehydrogenases present in hepatocytes. Excretion of DCE has not been studied.
Clinical symptoms associated with exposure to DCE in air include nausea, drowsiness, fatigue, intracranial pressure, and ocular irritation. No information is available on its toxic effects in people who ingest it or have dermal contact. Pathologic lesions of the heart, liver, and lung have been reported in rats exposed to trans-1,2-DCE in air. Rats in those studies experienced ataxia and respiratory depression before dying. Those effects have not been seen in people.
People who have inhaled DCE have had central nervous system effects such as dizziness, drowsiness, vertigo, and intracranial pressure. Those symptoms disappeared quickly after exposure stopped. The pharmacologic basis for DCE-mediated narcosis has not been studied.
To date, the association between exposure to the cis- and trans- isomers of DCE and
development of cancer in people and in animals has not been studied.
REFERENCES
Agency for Toxic Substances and Disease Registry. 1992. Toxicological Profile for
1,2-dichloroethylene.
Comments from Public Comment Period
Comments on McChord Air Force Base Public Health Assessment
The following comments (bold print) were received by ATSDR in response to the public comment period for the McChord Air Force Base Public Health Assessment. This list does not include comments on the accuracy of stated facts. If the accuracy of a statement was questioned, the statement was verified or corrected. If the same comments were received from more than one source, only one comment and response is listed. ATSDR's response follows each comment.
1) References to the 1983 AFOEHL study should be removed because the original data is missing. It is not possible to review the results or the sampling and analytical procedures to check if proper quality control measures were performed. The data is very suspect because the results were not duplicated during the RI in which proper QA/QC procedures were performed.
2) Since metals are not contaminants of concern at the ALGT, there is no reason to waste limited resources sampling for metals.
3) One letter received during the public comment period contained comments, concerns, and questions about the exposure of residents in the American Lake Garden Tract (ALGT) to drinking water from private wells contaminated with chemical wastes disposed of at McCAFB. The following questions/comments related to the environmental contamination from McCAFB in the ALGT and subsequent health concerns are extracted from the letter:
a) Why was the entire ALGT area included in the cancer rate calculations, when only a few people in the northwest corner were exposed to the contamination? (If only the people actually exposed to the contaminated water were included in the computation of the disease rate, the writer believes that a greater rate of cancer would be seen that would be above normal levels.)
b) The ALGT area has a highly transient population (military). The government (ATSDR) cannot show accurate numbers concerning cancer, heart disease, etc., because they have never followed people living here, then moving on to other areas of the United States. Has the government followed the personnel stationed at McCAFB in the early days?
c) In the 1940s - 1960s, the time of highest contamination, the number of people living in the area was much smaller than it is today.
d) Concern was expressed that children and grandchildren of those exposed may have adverse health effects.
