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PUBLIC HEALTH ASSESSMENT

ARNOLD ENGINEERING DEVELOPMENT CENTER
(a/k/a ARNOLD AIR FORCE BASE)
ARNOLD AIR FORCE BASE STATION, COFFEE COUNTY, TENNESSEE


TABLES

Table 1. Evaluation of Potential Public Health Hazards Associated With the Installation Restoration Program (IRP) Sites at Arnold Air Force Base

IRP
Site
SWMU Site Description/
Waste Disposal History
Investigation Results/ Environmental Monitoring Results Corrective Activities and/or Current Status Public Health Evaluation
(1) Leaching Pit No. 2/ Landfill No. 2 1 Solid Waste Management Unit (SWMU) 1, Landfill No. 2, is a 19.5-acre site located west of the main area of the base. The landfill was a hazardous materials disposal area from 1956 to 1982. Wastes included solvents, acids, fuels and propellants, metal salts, paint solids and thinner, caustics, and beryllium-contaminated clothing. In 1970, the landfill was expanded to also receive non-hazardous wastes. From 1982 on, only rinsed pesticide containers and shop wastes were disposed of at the landfill. The landfill was closed in 1992. Shallow Groundwater: The following volatile organic compounds (VOCs) were detected above ATSDR comparison values (CVs), with maximum concentrations given in parentheses: 1,1-dichloroethene (DCE) (1,900 parts per billion [ppb]), 1,1,1-trichloroethane (1,1,1-TCA) (14,026 ppb), trichloroethene (TCE) (88,772 ppb), benzene (30 ppb), toluene (8,900 ppb), tetrachloroethene (PCE) (40,000 ppb), methylene chloride (12,000 ppb), acetone (13,000 ppb), 4-methyl-2-pentanone (35,000 ppb), 1,1,2,2-tetrachloroethane (PCA) (990 ppb), and vinyl chloride (29 ppb). Arsenic (maximum 260 ppb) and lead (maximum 84 ppb) were detected above background and above CVs. Nickel was detected at background levels.
Deep Groundwater: TCE (maximum 26 ppb) and methylene chloride (maximum 10 ppb) were detected above CVs. Arsenic (maximum 50 ppb) and lead (maximum 64 ppb) were detected above background and above their CVs. Chromium was detected slightly above background but below its CV.
Subsurface Soil: Arsenic was detected at background levels.
Resource Conservation and Recovery Act (RCRA) Facility Investigation (RFI) is complete. Construction of a groundwater treatment unit (GWTU) was completed in July 1994. Construction of a clay cap over the landfill was completed in December 1997. A long-term groundwater monitoring program is ongoing. No exposure to subsurface soil is expected; thus, there is no public health hazard.

Past exposure to levels of contamination detected in off-site wells did not pose a public health hazard. Off-site residents with contaminated wells have been provided with filter systems; thus, there is no current health hazard. No future health hazard is expected assuming regular groundwater monitoring is conducted.

2 Leach Pit No. 2 (southeast of Landfill No. 2) was a soil-lined pit (15 feet in diameter) filled with limestone rocks. It received various acids during its operations including chromium and nickel plating acids and sulfuric, phosphoric, nitric, and hydrochloric acids. Groundwater: See SWMU 1.
Subsurface Soil: Arsenic was detected at background levels.
See SWMU 1. See SWMU 1.
(2) Retention Reservoir 3 SWMU 3, the Retention Reservoir, is an 175-acre unlined surface impoundment that collects cooling water from the J-4 area, surface runoff from the main area of the base, and discharge from the chemical treatment pond (SWMU 15). After National Pollutant Discharge Elimination System requirements are met, the water is discharged to Woods Reservoir via Rowland Creek. Sediment: Cadmium and beryllium were detected above background, but below their CVs. Lead was detected above background and above its CV, at a maximum of 730 parts per million (ppm). RFI is complete. No public exposure to sediments is expected; thus, there is no public health hazard.

Past exposure to levels of contamination detected in off-site wells did not pose a public health hazard. Off-site residents with contaminated wells have been provided with filter systems; thus, there is no current health hazard. No future health hazard is expected assuming regular monitoring is conducted.

4 SWMU 4 is a series of drainage ditches that transfer contact and non-contact cooling water from the J-4 area to the Retention Reservoir. Surface Water: PCE (maximum 28 ppb), TCE (maximum 160 ppb), and 1,1-DCE (maximum 5 ppb) were detected above CVs.
Sediment: Arsenic was detected at background levels.
RFI is underway. No public exposure to surface water or sediment in the drainage ditches is expected; thus, there is no public health hazard.
(3) Coffee County Landfill 5 Coffee County Landfill is a 97-acre inactive landfill located in the northwest corner of the base on State Route 55. The landfill property was leased from the Air Force by the County during the period of landfill operation (January 1972 to February 1989). It received municipal wastes from the cities of Manchester and Tullahoma, and non-hazardous wastes from AAFB from 1982 to 1989. Shallow Groundwater: The following metals were detected slightly above background levels and above CVs, with maximum concentrations given in parentheses: lead (13 ppb), chromium (151 ppb), and nickel (663 ppb; above the child CV but below the adult CV). Other metals were detected at background levels and/or below CVs. The following VOCs were detected above CVs, with maximum concentrations given in parentheses: vinyl chloride (61 ppb), PCE (310 ppb), TCE (110 ppb), benzene (18 ppb), methylene chloride (78 ppb), and 1,1-DCE (1 ppb).
Deep Groundwater: Metals and hydrocarbons were detected at background levels. (In the vicinity of the site, the deep aquifer has background concentrations of naturally occurring hydrocarbons.)
Subsurface Soil: Beryllium and chromium were detected above background but below their CVs; arsenic was detected at background levels.
Surface Water: 1,2-Dichloroethane (DCA) was detected above its CV, at a maximum of 1 ppb.
Methane Migration: See the discussion in the body of the document.
A municipal water supply line was extended to 11 residences along State Route 55 in 1992. A security fence around the site was constructed in 1993. A clay cap was completed in August 1998. A pilot groundwater treatment system was constructed in 1994, and updated to increase production in 1997. RFI is complete. A long-term groundwater monitoring program is ongoing. A methane collection and flaring system was installed in 1999. Methane monitoring at nearby residences has been completed because the Air Force and Coffee County extended the municipal water supply lines to residences along the Old Tullahoma Highway and plugged and abandoned the wells at those residences to eliminate pathways for methane to migrate upwards. No exposure to subsurface soil or surface water is expected; thus, there is no public health hazard.

No contamination above CVs has been detected in off-site wells, and residences to the west of the site have been connected to the public water supply. Thus, there is no past or current public health hazard. No future public health hazard is expected assuming regular groundwater monitoring is conducted.

(4) Bradley Creek 6 Bradley Creek runs about 1.5 miles within the northeast section of the main facility and is a tributary of Woods Reservoir. It receives cooling water and runoff from Arnold Engineering Development Center (AEDC) outfall ditches H and F. The creek flows off the site through a skimming pond where floating debris and scum are collected and placed on the ground adjacent to the pond. Surface Water: Arsenic was detected above background and above its CV, at a maximum of 2.5 ppb. PCE was detected below its CV.
Sediment: Cadmium was detected above background but below its CV. Arsenic was detected at background levels.
RFI is underway. Sporadic exposure by the public to surface water and sediment is not expected to pose a public health hazard.
(6) Camp Forrest Water Treatment Plant 8 IRP Site 6 is the location of a former water treatment plant that served Camp Forrest. The concrete tanks of the abandoned plant were used as a disposal site for AEDC wastes from 1953 to 1980. Wastes included acids, chlorinated solvents, explosives, and rocket fuels, and were generally burned, ignited, or reacted. In 1980, the water treatment plant structures were demolished and filled with soil. Shallow Groundwater: The following VOCs were found above CVs, with maximum concentrations given in parentheses: benzene (7,300 ppb), toluene (2,600 ppb), 1,1-DCE (30,000 ppb), 1,2-DCA (85 ppb), PCA (12,000 ppb), 1,1,1-TCA (26,000 ppb), methylene chloride (350,000 ppb), trichlorofluoromethane (TCFM) (170,000 ppb), and B2EHP (71 ppb). Metals were detected at background levels and/or below CVs.
Deep Groundwater: Metals were detected at background levels, and B2EHP was detected, most likely as a result of laboratory contamination.
Subsurface Soil: PCA was detected above its CV, at a maximum of 7.3 ppm. Other VOCs were detected below their CVs. Cadmium was detected above background and above the child CV, but below the adult CV, at a maximum of 21 ppm. Arsenic was detected slightly above background and above its CV at a maximum of 31 ppm.
A security fence was erected around the site in February 1994. RFI is complete. An interim corrective measure, which included removal and treatment of contaminated water and capping of the site, was implemented in 1995, and a GWTU was established in 1996 and was expanded in 1998. No exposure to subsurface soil is expected; thus, there is no public health hazard.

Past exposure to levels of contamination detected in off-site wells did not pose a public health hazard. Off-site residences in the path of the plume are being connected to the public water supply; thus, there is no current public health hazard. No future health hazard is expected assuming regular groundwater monitoring is conducted.

(7) AEDC Main Testing Area 74 The Main Testing Area (MTA) is a 250-acre area, located in the eastern portion of the base, encompassing the main research and development section of the base. It has been active since 1953. Wastes managed at this SWMU consist of spills or releases of fuels, propellants, and solvents. Shallow Groundwater: The following VOCs were detected above CVs, with maximum concentrations given in parentheses: 1,1-DCE (23,000 ppb), 1,2-DCA (0.9 ppb), PCE (128,000 ppb), TCE (920 ppb), and 1,1,1-TCA (10 ppb). Chromium was detected above background and above its CV at a maximum of 990 ppb; nickel was detected above background and above the child CV, but below the adult CV, at a maximum of 340 ppb. Other metals were detected at background levels and/or below comparison values.
Deep Groundwater: TCE was detected above its CV at a maximum of 2,700 ppb.
An Interim Control Measure to treat groundwater prior to surface discharge began operations in FY 1997. Past exposure to levels of contamination detected in off-site wells did not pose a public health hazard. Off-site residents with contaminated wells have been provided with filter systems; thus, there is no current health hazard. No future public health hazard is expected assuming regular groundwater monitoring is conducted.
(8) Leaching Pit No. 1 10 SWMU 10, Leach Pit No. 1, is located north of the MTA. It is a 10-foot diameter soil-lined pit filled with limestone rocks that was used from the 1950s to 1972 to neutralize acids from a metal cleaning process. Solvents were also disposed of at this SWMU. Groundwater: See SWMU 74.
Soil: PCE was detected above its CV at a maximum of 380 ppm. Cadmium was detected above background but below its CV.
Surface Water: The following VOCs were detected above CVs, with maximum concentrations given in parentheses: PCE (1,100 ppb), TCE (34 ppb), 1,1-DCE (57 ppb), 1,1,1-TCA (370 ppb), chloroform (7.2 ppb), and B2EHP (35 ppb). Nickel and vanadium were detected above background and above child CVs but below adult CVs at maxima of 600 ppb and 120 ppb respectively.
Sediment: Cadmium was detected above background but below its CV.
RFI is complete. Interim Control Measures to divert stormwater and treat contaminated groundwater and stormwater were completed in 1993. Closure of the PCE vapor degreaser building at the site occurred in 1994, and soil remediation was conducted in 1995. A GWTU was installed in 1997 and expanded in 1998. Long-term monitoring of groundwater began in 1997 and is ongoing. No public exposure to contaminated soil, surface water, or sediment is expected; therefore, there are no public health hazards.
(9) Brumalow Creek Drainage Area 11 Brumalow Creek is about 3 miles long; it is located in the southwest section of AEDC and discharges to Woods Reservoir. It receives runoff from the southern portion of AEDC. The creek flows off the site through a skimming pond where floating debris and scum are collected and placed on the ground adjacent to the pond. Surface Water: Arsenic was detected above background and above its CV at a maximum of 5.2 ppb. TCE (maximum 6 ppb) and 1,1-DCE (maximum 12 ppb) were detected above CVs.
Sediment: Benzo(a)pyrene was detected above its CV at a maximum of 1.8 ppm. Total polycyclic aromatic hydrocarbons (PAHs) (no CV) were detected at a maximum of 36.18 ppm. Arsenic was detected above background and above its CV at a maximum of 0.124 ppm. Cadmium was detected above background but below its CV.
RFI is underway. Sporadic exposure by the public to surface water and sediment is not expected to pose a public health hazard.
(10) Former Fire Training/ Landfill Burn Area 12 SWMU 12, the Fire Training Area, is a gravel pit 30 feet in diameter located northwest of the Main Test Area. Wastes were burned there approximately 20 times per year from 1973 to 1978. Liquids drain from the burn area via a pipe into a small pond to the west. Shallow Groundwater: The following VOCs were detected above CVs, with maximum concentrations given in parentheses: TCE (680 ppb), PCE (15 ppb), 1,1-DCE (300 ppb), 1,2-DCA (17 ppb), chloroform (200 ppb), methylene chloride (40 ppb), and B2EHP (18 ppb). Cadmium was detected slightly above background and above its CV, at a maximum of 44 ppb. Other metals were detected at background levels and/or below CVs.
Deep Groundwater: 1,1-DCE (maximum 150 ppb), methylene chloride (maximum 9 ppb), and B2EHP (maximum 9 ppb) were detected above CVs.
Subsurface Soil: Benzo(a)pyrene was detected above its CV, at a maximum of 8.6 ppm. Total PAHs (no CV) were detected at a maximum of 1,352 ppm. Lead was detected above background and above its CV, at a maximum of 1,510 ppm. Metals were detected at background concentrations and/or below CVs.
Sediment: Cadmium and beryllium were detected above background but below their CVs.
RFI is complete. Long-term monitoring of groundwater is ongoing. No public exposure to subsurface soil or sediment is expected; thus, there are no public health hazards.

Past exposure to levels of contamination detected in off-site wells did not pose a health hazard. Off-site residents with contaminated wells have been provided with filter systems; thus, there is no current public health hazard. No future health hazard is expected assuming regular groundwater monitoring is conducted.

13 SWMU 13, Burn Area No. 1, is located near SWMU 12. It was an open unlined pit in which waste oils, thinners, solvents, fuels, and solid wastes were burned from 1953 to the early 1970s. RFI is complete. Long-term monitoring of groundwater is ongoing.
14 SWMU 14, Landfill No. 1, is a 10-acre unlined landfill near SWMUs 12 and 13. From 1952 to the 1960s, it received facility refuse and metal shop wastes. In the 1960s, it also received construction debris. In the early 1970s, it received coal ash from the base Steam Plant. RFI is underway.
(11) Chemical Treatment Pond 15 SWMU 15, the Chemical Treatment Pond, is a 3-acre unlined pond located south of the Retention Reservoir. From 1961 to 1988, it was used for disposal of wastes such as caustic soda, nitric acid, hydrazine, aerozine, toluene, nitrogen tetroxide, red fuming nitric acid, and sodium perchlorate. The impoundment currently collects rainwater and discharges to the Retention Reservoir. Groundwater: See SWMU 3.
Sediment: Cadmium was detected above background but below its CV.
RFI is underway. No public exposure to sediment is expected; therefore, there is no public health hazard.
(12) Retention Leach Burn Area 16 SWMU 16, the Retention Leach/Burn Area, was a concrete pad draining into a concrete culvert that discharged into a soil depression. It operated in the 1950s and 1960s to transfer high energy fuels between tank trucks and for leaching and burning small quantities of fuels, propellants, and solvents. Shallow Groundwater: TCE (maximum 19 ppb) was detected over its CV and bis(2-ethylhexyl) phthalate (B2EHP) was detected, possibly as a result of laboratory contamination. Cobalt was detected slightly above background but below its CV. The groundwater plume discharges to Crimpton Creek, where the contaminant concentrations quickly dissipate in stream water
Subsurface Soil: TCE was detected below its CV. Cadmium was detected above background but below its CV.
Contaminated soil was excavated and subjected to biological treatment to reduce VOC levels, then returned to the site. This action was completed in 1993. Long-term groundwater monitoring began in 1997 and is ongoing. A Record of Decision recommending No Further Action has been submitted. No public exposure to subsurface soil is expected; therefore, there is no public health hazard.
(14) Crumpton Creek Surface Draining Area 18 Crumpton Creek is separated from the Retention Reservoir by an earthen dam, but some water can seep through. Therefore, Crumpton Creek has received some runoff and cooling water from the Retention Reservoir since 1953. Surface Water: TCE was detected above its CV at a maximum of 62 ppb.
Sediment: Arsenic was detected above background and above its CV, at a maximum of 230 ppm.
RFI is underway. Sporadic exposure by the public to surface water and sediment is not expected to pose a public health hazard.
(17) Burn Area 2 21 SWMU 21 consists of north and south burn units located east of the airfield runway. It was used once in 1983 as an open burning area for solid rocket fuel. Shallow Groundwater: Dieldrin was detected above its CV, at a maximum of 0.01 ppb. Chromium (maximum 108 ppb) and lead (maximum 47.9 ppb) were detected slightly above background and above CVs. Other metals were detected at background levels and/or below CVs.
Surface Soil: Arsenic was detected at background levels.
RFI is underway. The area has been approved for no further action. A well at the airfield used for showering and drinking water is regularly monitored because it is in the path of the northwest plume. No contamination has been detected; therefore, there is no public health hazard.
(19) Camp Forrest 24 Site 19 consists of a former World War II Army training base encompassing 5,000 acres. After the base was closed in 1946, buildings were torn down, leaving a network of foundations. Suspected operations include a fuel farm, incinerator, landfills, motor pools, gas stations, vehicle maintenance areas, and shops and warehouses. There is a possibility of soil and groundwater contamination from ordnance, pharmacy waste, fuel, and oil. Surface Soil: Arsenic (maximum 18.3 ppm), iron (maximum 64,100 ppm), and lead (maximum 1,300 ppm) were detected above background and above CVs. Other metals and organic compounds were detected at background levels or below CVs.
Subsurface Soil: The following PAHs were detected above CVs at the stated maxima in ppm: Benzo(a)pyrene (14), benzo(a)anthracene (15), benzo(b)fluoranthene (21), benzo(k)fluoranthene (23), dibenzo(a,h)anthracene (0.76), and indenopyrene (3.6). Arsenic (maximum 43 ppm) and iron (maximum 134,000 ppm) were detected above CVs.
Groundwater: Benzene (maximum 540 ppb), toluene (maximum 1,060 ppb), arsenic (maximum 14 ppb), iron (maximum 11,800 ppb) and lead (maximum 46.9 ppb), and manganese (maximum 7,610 ppb) were detected above CVs. Total petroleum hydrocarbons (TPH) were detected at a maximum of 103,000 ppb (no CV). Other organic compounds and metals were detected below CVs.
A Preliminary Assessment identified 74 potential areas of contamination, which have been further investigated in a Confirmatory Sampling program. RFI is pending. Sporadic public exposure to contaminated surface soil is not expected to pose a public health hazard.

No groundwater supply wells are in the vicinity of the contamination; therefore, no public health hazard exists.

(20) Steam Plant 25 SWMU 25, the Steam Plant Ash Pits, consisted of three interconnected below-grade steel hoppers and pits located to the southwest of Building 1418. The units were used to collect the coal ash slurry generated from coal burning operations. The pits were in operation from 1953 to 1969. Subsurface Soil: Arsenic was detected at background levels.
Sediment: The following PAHs were detected above CVs, with maximum concentrations given in parentheses: benzo(a)anthracene (9.1 ppm), benzo(a)pyrene (9 ppm), benz(b)fluoranthene (11 ppm), dibenzo(a,h)anthracene (3 ppm), and indeno(1,2,3-cd)pyrene (9 ppm). A maximum of 140.75 ppm total PAHs (no CV) were detected. Arsenic was detected slightly above background and above its CV; cadmium was detected above background but below its CV.
An Interim Control Measure, consisting of removal of boiler ash and asbestos debris from the pits, was completed in August 1992. RFI is underway. No public exposure to subsurface soil or sediment is expected; therefore, no public health hazard exists.
(22) Main Test Area Groundwater and RCRA Corrective Action Program 22 SWMU 22 (Landfill No. 3) is an unlined landfill that received refuse from the University of Tennessee Space Institute and AEDC. The facility was in operation from the early 1960s until 1970; it reportedly received no hazardous wastes. The landfill has been covered with 6 to 8 inches of soil. Shallow Groundwater: Chromium was detected slightly above background and above its CV at a maximum of 153 ppb. Other metals were detected at background levels and/or below CVs. B2EHP was detected, possibly as a result of laboratory contamination.
Subsurface Soil: Metals were detected at background levels.
RFI is underway. A well at the Girl Scout Camp is located approximately 1.5 miles to the southeast. It is occasionally used for drinking water. Low levels of contamination detected is not sufficient to be likely to pose a threat to this well.
29 SWMU 29 (Unpaved Roads) consists of the Old Hunters Check Station Road and associated drainage ditches. Waste oil was applied to the road for dust control from about 1965 to 1979. The waste oils were mainly crankcase oils generated by the AEDC automotive and locomotive repair shops. Surface Soil: Benzo(a)pyrene (maximum 0.15 ppm) and Aroclor 1254 (maximum 2.7 ppm) were detected above CVs. Metals were detected at background levels. RFI is underway. Sporadic public exposure to contaminated surface soil is not expected to pose a health hazard.
30 SWMU 30 is the Building 2207 Hazardous Waste Container Storage. None. This site is a RCRA Active Unit. The area has been approved for no further action. No public health hazard exists. This facility is operated according to RCRA safety regulations.
31 SWMU 31 is the Building 2212 Hazardous Waste Container Storage. None. This site is a RCRA Active Unit. The area has been approved for no further action. No public health hazard exists. This facility is operated according to RCRA safety regulations.
32 SWMU 32 is the Building 2218 Hazardous Waste Container Storage. None. This site is a RCRA Active Unit. The area has been approved for no further action. No public health hazard exists. This facility is operated according to RCRA safety regulations.
(22) Continued 39 SWMU 39, the Waste Accumulation Area, was located next to an electrical substation at the Engine Test Facility near Building 873. It received drums of hazardous waste and/or waste oils from Satellite Accumulation Areas 55 through 58 for temporary storage. Waste material is no longer stored in this area. Surface Soil: Metals were detected at background levels and/or below CVs. RFI is underway. The area has been approved for no further action. No public health hazard exists. Contamination detected was not at levels of health concern.
43 SWMU 43, a Satellite Accumulation Area, was located near the northwest corner of Building 579. Approximately 55 gallons of material were stored there. Waste material is no longer stored in this area. Subsurface Soil: 1,4-dioxane was detected below its CV. RFI is underway. The area has been approved for no further action. No public health hazard exists. Contamination detected was not at levels of health concern.
44 SWMU 44, a Satellite Accumulation Area, was located on a gravel pad along the west side of Building 676. Approximately 55 gallons of Varsol and isopropyl alcohol were typically stored there. Waste material is no longer stored in this area. Surface and Subsurface Soil: Metals were detected at background levels and/or below CVs. RFI is underway. The area has been approved for no further action. No public health hazard exists. Contamination detected was not at levels of health concern.
49 SWMU 49, a Satellite Accumulation Area, was located behind Building 1075. Approximately 55 gallons of waste oil and Freon are stored there. Staining was observed on the gravel around this area during the RCRA Facility Assessment (RFA) site visit. Waste material is no longer stored in this area. Surface and Subsurface Soil: PCE was detected below its CV. RFI is underway. The area has been approved for no further action. No public health hazard exists. Contamination detected was not at levels of health concern.
(22) Continued 50 SWMU 50, a Satellite Accumulation Area, was located within the MTA near Building 780. Approximately 50 to 150 gallons of waste oil contaminated with 1,1,1-TCA were stored there. Staining was observed on the gravel underlying this area during the RFA site visit. Surface and Subsurface Soil: 1,4-Dioxane was detected below its CV. RFI is underway. No public health hazard exists. Contamination detected was not at levels of health concern.
59 SWMU 59, a 10-foot long drum rack, was located outside Building 640. The rack was on a concrete pad and had a 6-inch wide drain that flowed into a 150-gallon metal sump. Surface Soil: PCE was detected above its CV at a maximum of 25 ppm. Other VOCs were detected below CVs. RFI is underway. No public exposure to contaminated soil is expected; therefore, no public health hazard exists.
62 SWMU 62, a 15-foot long drum rack, was located outside Building 780. The rack was located on a graveled pad and had a 6-inch wide drain that overflowed into a pail. Surface Soil: 1,1,1-TCA was detected below its CV. RFI is underway. No public health hazard exists. Contamination detected was not at levels of health concern.
63 SWMU 63, a single drum of 1,1,1-TCA, was located on a gravel area near the southwest corner of Building 579. The collection system was an evaporation pail. Surface Soil: Dieldrin was detected below its CV. RFI is underway. The area has been approved for no further action. No public health hazard exists. Contamination detected was not at levels of health concern.
(22) Continued 64 SWMU 64 is the former site of a rack holding 5 drums, located on a concrete apron surrounded by gravel. During the RFA site visit, severe staining was observed on the gravel surrounding the apron. The drum rack and apron have since been removed. Surface Soil: Aldrin was detected above its CV at 0.13 ppm. Dieldrin was detected below its CV. RFI is underway. The area has been approved for no further action. No public exposure to contaminated soil is expected; therefore, no public health hazard exists.
67 SWMU 67 is a 40-foot long rack with 20 drums stacked two high. It is located behind Building 1401. Along the front of the drum rack is a 6-inch wide evaporation pan type collection system. During the RFA site visit, no evidence of release was observed. Surface Soil: Cadmium was detected above background, but below its CV. RFI is underway. The area has been approved for no further action. No public health hazard exists. Contamination detected was not at levels of health concern.
94 SWMU 94 is a fuel/water separator located approximately 0.75 miles northwest of the Retention Reservoir. It has been in operation since 1987. Shallow Groundwater: 1,1-DCE (maximum 14 ppb), PCE (maximum 28 ppb) and TCE (maximum 110 ppb) were detected above CVs. Metals were detected at background levels, and B2EHP was detected, probably as a result of laboratory contamination. RFI is underway. The area has been approved for no further action. Past exposure to levels of contamination detected in off-site wells did not pose a public health hazard. Off-site residents with contaminated wells have been provided with filter systems; thus, there is no current public health hazard. No future health hazard is expected assuming regular groundwater monitoring is conducted.
(22) Continued AOC C Area of Concern (AOC) C, the Nursery, covers approximately 2.5 acres east of Landfill No.2 and is overgrown with grass. Before 1982, the Nursery was a pesticide mixing, loading, and storage area for AEDC, although the exact location of the mixing and loading has not been determined. Since 1982, the area has been used for mulch and straw storage. Surface Soil: Metals were detected at background levels and/or below CVs.
Subsurface Soil: 4,4-Dichloro diphenyl trichloroethane (DDT) was detected above its CV, at a maximum of 21 ppm. Arsenic was detected at background levels.
RFI is underway. No public health hazard exists. Contamination in surface soil was below levels of health concern and no exposure to subsurface soil is expected.
AOC M AOC M (SWMU 98), the Explosive Ordnance Disposal Range, consists of an open area approximately 150 feet in diameter located southwest of the airfield used for open detonation of explosives. Explosive materials are detonated in 6 foot deep trenches and include triethyl aluminum, strontium perchlorate, small arms munitions, and solid propellant. Toxicity Characteristic Leaching Procedure analysis of 10 soil samples for VOCs and metals have shown no criteria exceedances. RFI is complete. No public health hazard exists; no contamination has been identified.

Notes:

  • "Shallow" groundwater includes both the shallow and intermediate aquifers; "Deep" groundwater denotes the Fort Payne aquifer.
  • IRP sites and SWMUs not included in this table have all been classified as "no further action."

Sources: AAFB 1995, 1998, 1999f.

KEY:
AEDC = Arnold Engineering Development Center
ATSDR= Agency for Toxic Substances and Disease Registry
B2EHP = bis(2-ethylhexyl) phthalate
CV = comparison value
DCA = dichloroethane
DCE = dichloroethene
MTA = Main Testing Area
PCE = tetrachloroethene
ppb = parts per billion
RCRA = Resource Conservation and Recovery Act
RFI = RCRA Facility Investigation
SWMU = Solid Waste Management Unit
TCE = trichloroethene
VOC = volatile organic compound


Table 2. Potential Exposure Pathways Evaluation Table

Pathway Name Exposure Pathway Elements Time of Exposure Comments
Source of Contamination Environmental Medium Point of Exposure Route of Exposure Exposed Population 
Methane migration from Coffee County Landfill Decomposition of waste in landfill Soil gas Confined areas such as basements, well houses Physical hazard (explosion) Nearby residents; high school students Past
Present
Future
An individual received burns from a flash fire at a residence where methane accumulated. Mitigation measures and monitoring by AAFB are expected to prevent a current or future health hazard.
Consumption of fish from Woods Reservoir Sediment contaminated by PCBs from AAFB Biota Consumption of fish Ingestion Anglers and their families Past
Present
Future
Past levels of PCB in catfish were higher than suggested for regular consumption. It is unknown whether any members of the public consumed catfish regularly enough to present a public health hazard. The existing advisory, if followed is sufficient to protect public health.
UXO and other physical hazards Former impact areas UXO Former impact areas Detonation of UXO Recreational Users Past
Present
Future
No accidents have been reported involving UXO or physical hazards. ATSDR considers UXO and physical hazards at AAFB to be indeterminate health hazards because it is not known how well-informed recreational users of AAFB are of the potential hazards. ATSDR concurs with AAFB's plans to increase notification efforts and recommends that additional efforts be made to notify all recreational users of potential hazards.
Camp Forrest Remnants of structures

Open manholes
Abandoned wells

Camp Forrest Physical injury Recreational users Past
Present
Future
Groundwater Coffee County Landfill plume Groundwater Off-site private wells Inhalation
Ingestion
Dermal
Users of off-site private wells Past
Present
Future
Levels of contaminants found in off-site wells pose no apparent public health hazard. Residents with contaminated wells, as well as some residents whose wells are not contaminated, have been provided with a filtration system or connected to a public water supply. ATSDR recommends continued monitoring of groundwater plumes and off-site private wells to ensure that contamination does not pose a health hazard in the future.
Camp Forrest plume Groundwater Off-site private wells Inhalation
Ingestion
Dermal
Users of off-site private wells Past
Present
Future
Northwest plume Groundwater Off-site private wells Inhalation
Ingestion
Dermal
Users of off-site private wells Past
Present
Future
Model Shop plume Groundwater Off-site private wells Inhalation
Ingestion
Dermal
Users of off-site private wells Past
Present
Future
Additional information will be necessary to define the off-site extent of contamination. Until additional information is analyzed, the potential exposure is indeterminate.
Surface soil Operations and waste management practices at AAFB Soil Contaminated areas at AEDC and at the former Camp Forrest Ingestion AEDC visitors
Recreational users
Past
Present
Future
No apparent public health hazard is associated with sporadic contact with contaminated soil by AEDC visitors and AAFB recreational users.
Surface water and sediment Operations and waste management practices at AAFB Surface water and sediment Surface water bodies (Woods Reservoir and on site retention ponds) Ingestion
Dermal contact
Recreational users Past
Present
Future
No apparent public health hazard is associated with sporadic contact to on-base surface water and sediment by AEDC visitors and AAFB recreational users. Levels of contamination in off-base surface water and springs pose no apparent public health hazard. ATSDR recommends continued monitoring of off-base water bodies to ensure that contamination does not exceed safe levels in the future.



Table 3. PCBs in Catfish from Woods Reservoir

Year Number of Samples Collected Minimum
PCB Concentration (ppm)
Maximum
PCB Concentration (ppm)
Average
PCB Concentration (ppm)
INDIVIDUAL SAMPLES
1987 4 0.62 1.94 1.14
1988 1 2.20 2.20 2.20
1989 3 0.54 1.57 1.21
1991 4 0.23 4.94 1.70
1994 4 0.10 0.70 0.46
1996 4 0.04 0.60 0.21
1998 4 0.1 0.5 0.31
COMPOSITE SAMPLES*
1987 4 0.25 0.73 0.52
1988 1 1.60 1.60 1.60
1991 4 0.09 5.56 1.70
1994 4 0.14 0.99 0.51
1996 4 0.05 0.37 0.15
1998 4 0.45 0.64 0.56

Source: AAFB, 1997 and 1999d.

*Each composite sample is normally made up of 4 fish, although the number of fish sometimes ranged from 2 to 5.



Table 4. Summary of Groundwater Plumes at Arnold Air Force Base

Groundwater Plumes

Location Contaminants above Comparison Values (CVs) in Off-site Wells Status
Coffee County Landfill
(western boundary of base)
None Waterlines were installed for residences in the vicinity as a precaution. Private wells were also plugged to eliminate possibility of methane migration.
Camp Forrest
(eastern portion of base)
None Waterlines are being installed for residences in the vicinity as precaution.
Northwest
(northwest portion of base)
TCE at 10 ppb in one residential drinking water well (1998) A water filter system was provided to residence.
Model Shop
(northern portion of base)
None (based on preliminary results) Preliminary results suggest that no contaminants at levels of health concern were found in private wells.



FIGURES


Figure 1. Location of Arnold Air Force Base (from AAFB, 1998)


Figure 2. Site Locations at Arnold Air Force Base (from AAFB, 1998)


Figure 3. Surface Water Drainage at Arnold Air Force Base (from SAIC, 1992)


Figure 4. AAFB Unexploded Ordnance (UXO) Hazards Card


Figure 5. Coffee County Landfill Groundwater Plume: Shallow Aquifer (from Brandon, 1999)


Figure 6. Coffee County Landfill Groundwater Plume: Intermediate Aquifer (from Brandon, 1999)


Figure 7. Camp Forrest Plume: TCFM and 1,1-DCE, Intermediate Aquifer (from CH2MHill, 1998)


Figure 8. Northwest Plume: Off-post Detections (from AAFB, 1999)


Figure 9. Model Shop Plume: Shallow Aquifer (from Brandon, 1999)


Figure 10. Model Shop Plume: Intermediate Aquifer (from Brandon, 1999)


APPENDIX A: ATSDR's Comparison Values

The conclusion that a contaminant exceeds the comparison value does not mean that it will cause adverse health effects. Comparison values represent media-specific contaminant concentrations that are used to select contaminants for further evaluation to determine the possibility of adverse public health effects. The following are various comparison values ATSDR used in this public health assessment.

Cancer Risk Evaluation Guides (CREGs)
Estimated contaminant concentrations that would be expected to cause no more than one excess cancer in a million (10-6) persons exposed over a 70-year life span. The Agency for Toxic Substances and Disease Registry's (ATSDR's) CREGs are calculated from the U. S. Environmental Protection Agency's (EPA's) cancer potency factors (CPFs).

Environmental Media Evaluation Guides (EMEGs)
EMEGs are based on ATSDR minimal risk levels (MRLs) and factor in body weight and ingestion rates. An EMEG is an estimate of daily human exposure to a chemical (in mg/kg/day) that is likely to be without noncarcinogenic health effects over a specified duration of exposure.

Maximum Contaminant Level (MCL)
The MCL is the drinking water standard established by EPA. It is the maximum permissible level of a contaminant in water that is delivered to the free-flowing outlet. MCLs are considered protective of public health over a lifetime (70 years) for people consuming 2 liters of water per day.

Reference Media Evaluation Guides (RMEGs)
ATSDR derives RMEGs from EPA's oral reference doses (RfDs). The RMEG represents the concentration in water or soil at which daily human exposure is unlikely to result in adverse noncarcinogenic effects.

Risk-Based Concentration (RBC)
The RBCs were developed by EPA Region III. RBCs for tap water, air, and soil were derived using EPA RfDs and cancer potency factors combined with standard exposure scenarios, such as ingestion of 2 liters of water per day, over a 70-year life span. RBCs are contaminant concentrations that are not expected to cause adverse health effects over long-term exposures.


APPENDIX B: Estimated Exposures and Health Effects

Estimates of Human Exposure Doses and Determination of Health Effects

Deriving Exposure Doses

The Agency for Toxic Substances and Disease Registry (ATSDR) estimated the human exposure doses from ingestion of drinking water from groundwater supplies and ingestion of fish. Deriving exposure doses requires evaluating the contaminant concentrations to which people may have been exposed and how often and how long exposures to those contaminants occurred. Together, these factors help influence the individual's physiological response to chemical contaminant exposure and the potential for noncancer or cancer outcomes. In the absence of exposure-specific information, ATSDR applied several conservative assumptions to define site-specific exposures as accurately as possible for people contacting contaminated media.

Evaluating Potential Health Hazards

The estimated exposure doses are used to evaluate potential noncancer and cancer effects associated with contaminants detected in site media. When evaluating noncancer effects, ATSDR first compares the estimated exposure dose to standard screening values, including ATSDR's minimal risk levels (MRLs) and the U.S. Environmental Protection Agency's (EPA) reference doses (RfDs), to evaluate whether adverse effects may occur. The chronic MRLs and RfDs are estimates of daily human exposure to a substance that is likely to be without appreciable risk of adverse noncancer effects over a specified duration. The chronic MRLs and RfDs are conservative values, based on the levels of exposure reported in the literature that represent no-observed-adverse-effects levels (NOAEL) or lowest-observed-adverse-effects-levels (LOAEL) for the most sensitive outcome for a given route of exposure (e.g., dermal contact, ingestion). In addition, uncertainty (safety) factors are applied to NOAELs or LOAELs to account for variation in the human population and uncertainty involved in extrapolating human health effects from animal studies. If estimated exposure doses are greater than the MRL or RfD, ATSDR reviews the toxicological literature to determine the likelihood of adverse effects.

When evaluating the potential for cancer to occur, ATSDR uses cancer potency factors (CPFs) that define the relationship between exposure doses and the likelihood of an increased risk of developing cancer over a lifetime. The CPFs are developed using data from animal or human studies and often require extrapolation from high exposure doses administered in animal studies to lower exposure levels typical of human exposure to environmental contaminants. The CPF represents the upper-bound estimate of the probability of developing cancer at a defined level of exposure; therefore, they tend to be very conservative (i.e., overestimate the actual risk) in order to account for a number of uncertainties in the data used in extrapolation.

ATSDR estimated the potential for cancer to occur using the following equation. The estimated exposure doses and CPF values for the contaminants of concern are incorporated into the equation:

Lifetime Cancer Risk = Estimated exposure dose (milligrams contaminant per kilogram body weight per day [mg/kg/day]) x CPF (mg/kg/day)-1

Although no risk of cancer is considered acceptable, because a zero cancer risk is not possible to achieve, ATSDR often uses a range of 10-4 to 10-6 estimated lifetime cancer risk (or 1 new case in 10,000 to 1,000,000 exposed persons), based on conservative assumptions about exposure, to determine whether there is a concern for cancer effects. This information is then evaluated with respect to the toxicological literature regarding a specific type of cancer.

Estimated Exposure Doses for Consumption of Catfish from Woods Reservoir

Since 1985, the state of Tennessee has advised anglers not to consume catfish from Woods Reservoir due to polychlorinated biphenyl (PCB) contamination. However, levels of PCBs found in fish have declined in recent years. Also, it is thought that not all anglers follow the advisory. Therefore, ATSDR evaluated whether consumption of fish from Woods Reservoir would pose a health hazard. ATSDR estimated exposure dose using levels of PCBs detected in fish from the reservoir in 1998 sampling. (See Table 3 for results of sampling for PCBs in catfish from Woods Reservoir from 1987 to 1998.)

ATSDR generally used "conservative" assumptions when calculating exposure doses. For example, the concentration used was a whole-fish concentration, which probably overestimates the concentrations present in a filet. Also, it was assumed that 100% of the PCBs consumed would be absorbed into the body, which is probably an overestimate. Finally, all PCBs detected were assumed to have the same toxicity as the most toxic PCB. (PCBs are a group of related chemical compounds of varying toxicities.) ATSDR uses these conservative assumptions to protect public health.

ATSDR used the following equation and exposure assumptions to estimate an exposure dose for fish consumption:

where:

C = Maximum concentration (ppm) adjusted for an assumed 30% reduction in PCB content due to cooking (Anderson et al., 1993)

IR = Intake rate: 0.0066 kg fish per day (about one 8 oz. filet per month) for adults (EPA, 1997); 0.0033 kg fish per day for children (50% of adult IR)

EF = Exposure frequency: 350 days/year

ED = Exposure duration: adult = 30 years; child = 5 years

BW = Body weight: adult = 71.8 kg (158 lbs); child = 15 kg (33 lbs) (EPA, 1997)

AT = Averaging time or the period over which cumulative exposures are averaged: 5 or 30 years x 365 days/year for noncancer effects and 70 years x 365 days/year for cancer effects

Noncancer

Estimated exposure doses of 0.00004 mg/kg/day for adults and 0.00009 mg/kg/day for children slightly exceed ATSDR's chronic MRL of 0.00002 mg/kg/day. The MRL is based on exposure levels to animals much higher than the levels of exposure expected from eating fish caught in Wood's Reservoir. This MRL contains a safety factor of 300 built into it to account for differences between animals and humans and for differing sensitivity to PCBs in human populations. (ATSDR, 1998).

Cancer

PCBs are classified by EPA as a "probable" human carcinogen, meaning that PCBs have been shown to cause cancer in laboratory animals, but there is not adequate epidemiologic evidence for humans. ATSDR derived lifetime cancer risk estimates for fish consumption based on the calculated exposure doses, using EPA's CPF for PCBs. These estimated risks were within the "acceptable" range of 10-4 to 10-6. Like the MRL, the CPF is based on animal studies and incorporates a large margin of safety (EPA, 1999). The CPF is a conservative overestimate of the true cancer risk, which may be as low as zero. It does not and can not predict cancer risks to an individual. It is intended as a probability estimate of the cancer risk to a population with a defined level of exposure over a lifetime .

Conclusions

Based on available sampling data, ATSDR found that levels of PCBs ingested by consuming approximately one 8-ounce meal per month of catfish from Woods Reservoir are not likely to cause an unacceptable increased cancer risk, but do exceed the comparison value for noncancer health effects (the MRL). There are uncertainties in the sampling data that may underestimate the potential for health risks from consuming the fish. This evaluation does not consider the possibility that other contaminants not related to AAFB might be present. Because of the uncertainties involved in sampling and testing fish and predicting health effects, ATSDR believes that the current advisory should remain in order to be certain that people do not consume PCBs at levels currently found in catfish samples.

In particular, pregnant women and children should be sure to follow the advisory to avoid eating catfish from Woods Reservoir. Studies of women who consumed PCB-contaminated fish from the Great Lakes while pregnant found that their children exhibited developmental and neurobehavioral effects (ATSDR, 1998)(2). As compared to adults, children receive a proportionally greater dose of PCBs relative to their body weight from consuming the same amount of fish. Also, because they are still developing, children are at potentially greater risk for certain types of health effects.

ATSDR is aware that some anglers may not choose to follow the catfish consumption advisory. Anyone who chooses not to follow the advisory should keep in mind that their potential risk increases the more fish they consume. PCB content in fish can be somewhat reduced by removing skin, trimming away the fatty part of the fish, and throwing away the oil and drippings produced from cooking the fish (TDEC, 1996). Catch and release fishing should not pose a health hazard to recreational users of Woods Reservoir.

Estimated Exposure Doses for Groundwater Use

Sampling of private wells near AAFB found one well with detected concentrations of trichloroethylene (TCE) above EPA's Maximum Contaminant Level (MCL). To determine whether exposures to this contaminant may be related to adverse health effects, if any, ATSDR estimated exposure dose for people using TCE-contaminated well water. In estimating to what extent people might be exposed to TCE, ATSDR used "conservative" assumptions about contaminant concentrations in well water, as well as how much and how often people drink well water. These assumptions allow ATSDR to estimate the highest possible exposure dose and determine the corresponding health effects. Although ATSDR expects that residents were not consistently exposed to the highest contaminant concentration, the "conservative" estimates are used to protect public health.

ATSDR used to following equation and exposure assumptions to estimate an exposure dose for water:

Estimated exposure dose=C x IR x EF x ED
             BW x AT

where:

C Maximum concentration detected (0.01 parts per million [ppm])
IR Intake rate (accounts for ingestion, inhalation, and dermal contact): adult=4 liters per day; child=3 liters per day
EF Exposure frequency: 365 days/year
ED Exposure duration or the duration over which exposure occurs: 40 years (from earliest possible time of contamination to 1998, when AAFB installed a filter at the resident's tap) for an adult; 6 years for a child
BW Body weight: adult = 71.8 kg (158 lbs); child = 15 kg (33 lbs) (EPA, 1997)
AT Averaging time or the period over which cumulative exposures are averaged (40 years x 365 days/year for noncancer effects and 70 years [considered a lifetime] x 365 days/year for cancer effects)

Sampling of off-site wells found one well with concentrations of TCE over the MCL. In 1998, the Air Force provided this residence with bottled water and then installed a filter at the tap. Evaluation of exposures and doses found that use of this well in the past is unlikely to result in noncancer or cancer health effects.

Noncancer

In ATSDR Toxicological Profiles, MRLs are developed for acute, intermediate, and chronic exposure intervals. An MRL for TCE is only available for acute (14 days or less) exposures and was used to evaluate potential noncancer effects associated with drinking water exposures. The resulting estimated exposure doses of 0.0006 mg/kg/day for adults and 0.002 mg/kg/day for children do not exceed ATSDR's MRL of 0.2 mg/kg/day for acute oral exposure. The MRL is based on exposure levels to animals with an uncertainty or safety factor of 300 built into it (ATSDR, 1997). A chronic oral exposure MRL or a chronic oral RfD is not available for TCE. ATSDR reviewed the available toxicologic studies using intermediate and chronic exposures for animals and found that the conservative exposure dose estimates for the off-site residents were less than the lowest LOAEL in the literature.

Cancer

Although TCE has been shown to produce cancer in experimental animals when administered in large doses, the link between TCE in drinking water and human cancer cases is not well established (ATSDR, 1997). EPA, in an effort to determine a cancer classification for TCE, is currently reviewing the scientific literature pertaining to the carcinogenicity of TCE. For screening purposes, ATSDR used a previously derived CPF for TCE of 0.011 (mg/kg/day)-1. This approach provides a conservative evaluation of the likelihood of exposures to TCE in drinking water supplies. ATSDR derived a lifetime cancer estimate for residents from drinking water below 4 x 10-6 (or an increased likelihood of 4 in 1,000,000 of developing cancer). This estimate is within the "acceptable" range of 10-4 to 10-6; further, adults and children are extremely unlikely to use water at the maximum contamination concentration over the entire exposure period and at the frequency and duration assumed.


APPENDIX C: Glossary

Absorption:
How a chemical enters a person's blood after the chemical has been swallowed, has come into contact with the skin, or has been breathed in.


Acute Exposure:
Contact with a chemical that happens once or only for a limited period of time. ATSDR defines acute exposures as those that might last up to 14 days.


Additive Effect:
A response to a chemical mixture, or combination of substances, that might be expected if the known effects of individual chemicals, seen at specific doses, were added together.


Adverse Health Effect:
A change in body function or the structures of cells that can lead to disease or health problems.


ATSDR:
The Agency for Toxic Substances and Disease Registry. ATSDR is a federal health agency in Atlanta, Georgia that deals with hazardous substance and waste site issues. ATSDR gives people information about harmful chemicals in their environment and tells people how to protect themselves from coming into contact with chemicals.


Background Level:
An average or expected amount of a chemical in a specific environment. Or, amounts of chemicals that occur naturally in a specific environment.


Biota:
Used in public health, things that humans would eat - including animals, fish and plants.


Cancer:
A group of diseases which occur when cells in the body become abnormal and grow, or multiply, out of control


Carcinogen:
Any substance shown to cause tumors or cancer in experimental studies.


CERCLA:
See Comprehensive Environmental Response, Compensation, and Liability Act.


Chronic Exposure:
A contact with a substance or chemical that happens over a long period of time. ATSDR considers exposures of more than one year to be chronic.


Completed Exposure Pathway:
See Exposure Pathway.


Comparison Value (CVs):
Concentrations or the amount of substances in air, water, food, and soil that are unlikely, upon exposure, to cause adverse health effects. Comparison values are used by health assessors to select which substances and environmental media (air, water, food and soil) need additional evaluation while health concerns or effects are investigated.


Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA):
CERCLA was put into place in 1980. It is also known as Superfund. This act concerns releases of hazardous substances into the environment, and the cleanup of these substances and hazardous waste sites. ATSDR was created by this act and is responsible for looking into the health issues related to hazardous waste sites.


Concern:
A belief or worry that chemicals in the environment might cause harm to people.


Concentration:
How much or the amount of a substance present in a certain amount of soil, water, air, or food.


Contaminant:
See Environmental Contaminant.


Delayed Health Effect:
A disease or injury that happens as a result of exposures that may have occurred far in the past.


Dermal Contact:
A chemical getting onto your skin. (see Route of Exposure).


Dose:
The amount of a substance to which a person may be exposed, usually on a daily basis. Dose is often explained as "amount of substance(s) per body weight per day".


Dose / Response:
The relationship between the amount of exposure (dose) and the change in body function or health that result.


Duration:
The amount of time (days, months, years) that a person is exposed to a chemical.


Environmental Contaminant:
A substance (chemical) that gets into a system (person, animal, or the environment) in amounts higher than that found in Background Level, or what would be expected.


Environmental Media:
Usually refers to the air, water, and soil in which chemical of interest are found. Sometimes refers to the plants and animals that are eaten by humans. Environmental Media is the second part of an Exposure Pathway.


U.S. Environmental Protection Agency (EPA):
The federal agency that develops and enforces environmental laws to protect the environment and the public's health.


Epidemiology:
The study of the different factors that determine how often, in how many people, and in which people will disease occur.


Exposure:
Coming into contact with a chemical substance.(For the three ways people can come in contact with substances, see Route of Exposure.)


Exposure Assessment:
The process of finding the ways people come in contact with chemicals, how often and how long they come in contact with chemicals, and the amounts of chemicals with which they come in contact.


Exposure Pathway:
A description of the way that a chemical moves from its source (where it began) to where and how people can come into contact with (or get exposed to) the chemical.

ATSDR defines an exposure pathway as having 5 parts:

  • Source of Contamination,

  • Environmental Media and Transport Mechanism,

  • Point of Exposure,

  • Route of Exposure; and,

  • Receptor Population.

When all 5 parts of an exposure pathway are present, it is called a Completed Exposure Pathway. Each of these 5 terms is defined in this Glossary.


Frequency:
How often a person is exposed to a chemical over time; for example, every day, once a week, twice a month.


Hazardous Waste:
Substances that have been released or thrown away into the environment and, under certain conditions, could be harmful to people who come into contact with them.


Health Effect:
ATSDR deals only with Adverse Health Effects (see definition in this Glossary).


Indeterminate Public Health Hazard:
The category is used in Public Health Assessment documents for sites where important information is lacking (missing or has not yet been gathered) about site-related chemical exposures.


Ingestion:
Swallowing something, as in eating or drinking. It is a way a chemical can enter your body (See Route of Exposure).


Inhalation:
Breathing. It is a way a chemical can enter your body (See Route of Exposure).


LOAEL:
Lowest Observed Adverse Effect Level. The lowest dose of a chemical in a study, or group of studies, that has caused harmful health effects in people or animals.


Malignancy:
See Cancer.


MRL:
Minimal Risk Level. An estimate of daily human exposure - by a specified route and length of time -- to a dose of chemical that is likely to be without a measurable risk of adverse, noncancerous effects. An MRL should not be used as a predictor of adverse health effects.


NPL:
The National Priorities List. (Which is part of Superfund.) A list kept by the U.S. Environmental Protection Agency (EPA) of the most serious, uncontrolled or abandoned hazardous waste sites in the country. An NPL site needs to be cleaned up or is being looked at to see if people can be exposed to chemicals from the site.


NOAEL:
No Observed Adverse Effect Level. The highest dose of a chemical in a study, or group of studies, that did not cause harmful health effects in people or animals.


No Apparent Public Health Hazard:
The category is used in ATSDR's Public Health Assessment documents for sites where exposure to site-related chemicals may have occurred in the past or is still occurring but the exposures are not at levels expected to cause adverse health effects.


No Public Health Hazard:
The category is used in ATSDR's Public Health Assessment documents for sites where there is evidence of an absence of exposure to site-related chemicals.


PHA:
Public Health Assessment. A report or document that looks at chemicals at a hazardous waste site and tells if people could be harmed from coming into contact with those chemicals. The PHA also tells if possible further public health actions are needed.


Plume:
A line or column of air or water containing chemicals moving from the source to areas further away. A plume can be a column or clouds of smoke from a chimney or contaminated underground water sources or contaminated surface water (such as lakes, ponds and streams).


Point of Exposure:
The place where someone can come into contact with a contaminated environmental medium (air, water, food or soil). For examples:
the area of a playground that has contaminated dirt, a contaminated spring used for drinking water, the location where fruits or vegetables are grown in contaminated soil, or the backyard area where someone might breathe contaminated air.


Population:
A group of people living in a certain area; or the number of people in a certain area.


Public Health Assessment(s):
See PHA.


Public Health Hazard:
The category is used in PHAs for sites that have certain physical features or evidence of chronic, site-related chemical exposure that could result in adverse health effects.


Public Health Hazard Criteria:
PHA categories given to a site which tell whether people could be harmed by conditions present at the site. Each are defined in the Glossary. The categories are:
  1. Urgent Public Health Hazard

  2. Public Health Hazard

  3. Indeterminate Public Health Hazard

  4. No Apparent Public Health Hazard

  5. No Public Health Hazard

Receptor Population:
People who live or work in the path of one or more chemicals, and who could come into contact with them (See Exposure Pathway).


Reference Dose (RfD):
An estimate, with safety factors (see safety factor) built in, of the daily, life-time exposure of human populations to a possible hazard that is not likely to cause harm to the person.


Route of Exposure:
The way a chemical can get into a person's body. There are three exposure routes:
- breathing (also called inhalation),
- eating or drinking (also called ingestion), and
- or getting something on the skin (also called dermal contact).


Safety Factor:
Also called Uncertainty Factor. When scientists don't have enough information to decide if an exposure will cause harm to people, they use "safety factors" and formulas in place of the information that is not known. These factors and formulas can help determine the amount of a chemical that is not likely to cause harm to people.


SARA:
The Superfund Amendments and Reauthorization Act in 1986 amended CERCLA and expanded the health-related responsibilities of ATSDR. CERCLA and SARA direct ATSDR to look into the health effects from chemical exposures at hazardous waste sites.


Source (of Contamination):
The place where a chemical comes from, such as a landfill, pond, creek, incinerator, tank, or drum. Contaminant source is the first part of an Exposure Pathway.


Special Populations:
People who may be more sensitive to chemical exposures because of certain factors such as age, a disease they already have, occupation, sex, or certain behaviors (like cigarette smoking). Children, pregnant women, and older people are often considered special populations.


Superfund Site:
See NPL.


Synergistic effect:
A health effect from an exposure to more than one chemical, where one of the chemicals worsens the effect of another chemical. The combined effect of the chemicals acting together are greater than the effects of the chemicals acting by themselves.


Toxic:
Harmful. Any substance or chemical can be toxic at a certain dose (amount). The dose is what determines the potential harm of a chemical and whether it would cause someone to get sick.


Toxicology:
The study of the harmful effects of chemicals on humans or animals.


Tumor:
Abnormal growth of tissue or cells that have formed a lump or mass.


Uncertainty Factor:
See Safety Factor.


Urgent Public Health Hazard:
This category is used in ATSDR's Public Health Assessment documents for sites that have certain physical features or evidence of short-term (less than 1 year), site-related chemical exposure that could result in adverse health effects and require quick intervention to stop people from being exposed.

2. Based on their recollection, these women consumed about one and a half 8-ounce meals of fish from Lake Michigan per month during their pregnancies; median PCB concentrations in different species of Lake Michigan fish [cooked] have been reported to range from 0.17 ppm to 3.01 ppm. It should be noted that some methodological criticisms of this study have been made; for example, co-exposure to other chemicals such as PBBs (polybrominated biphenyls) was not accounted for (ATSDR, 1998).


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