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PUBLIC HEALTH ASSESSMENT

JET PROPULSION LABORATORY (NASA)
PASADENA, LOS ANGELES COUNTY, CALIFORNIA


TABLES

Table 1.

Evaluation of Potential Public Health Hazards at the Jet Propulsion Laboratory
Site Site Description / Waste Disposal History Investigation Results/ Environmental Monitoring Results Corrective Activities and/or Current Status Evaluation of Public Health Hazard
OU 1: On-site Groundwater
Groundwater Carbon tetrachloride (CTC), tetrachloroethylene (PCE), and trichloroethylene(TCE) were discovered in on-site groundwater in 1990. Perchlorate was discovered in 1997. Since long-term on-site groundwater monitoring began in June/July 1994, CTC (nondetectable (nd)-310 ppb) has been detected above maximum contaminant levels (MCLs) in 12 wells; TCE (nd-73 ppb) has been detected above MCLs in eight wells; and dichloroethane (DCA) (nd-8.9 ppb) has been detected above MCLs in four wells. Perchlorate analysis in January/February 1998 indicated concentrations (nd-1,230 ppb) above California's action level in five wells. Quarterly groundwater monitoring continues to track contaminant movement. No treatment is currently being performed. The remedial investigation/feasibility study (RI/FS) is ongoing and is scheduled for completion in early 1999. JPL is considering an interim removal action, using soil-vapor extraction, to begin removing volatile organic compound (VOC) vapors in soil that may be contaminating groundwater on site. No public health hazard is associated with groundwater at JPL because there is no known exposure to groundwater on site.
OU 2: On-site Contamination Sources
The following seepage pits and waste pits were used between 1940 and 1960 for disposal of liquid hazardous wastes.
Seepage Pits 1, 2, 3, 4, and 35 Seepage Pits 1, 2, and 35 are located beneath a paved parking lot north of Building 11, and Seepage Pits 3 and 4 are located beneath flower planters west and north of Building 11, respectively; these sites are inaccessible to JPL employees. Seepage Pits 1 and 2 are located in the area with the longest history of use at JPL. Seepage Pits 3 and 4 apparently were connected to Building 11, where solvents may have been used for plumbing and electrical work. Seepage Pit 35 was connected to former Building 81, which housed workshops, storage rooms, and offices. Seepage Pit 4 was inaccessible to soil boring. Sampling at Seepage Pits 1 and 35 was performed during a pre-RI investigation.

Soil gas: Chloroform, CTC, dichloroethene (DCE), and 1,1,1-trichloroethane (TCA) were detected in one or more of these seepage pits.

Subsurface soil1: One semivolatile organic compound (SVOC) was detected below comparison values (CVs) in one sample. No metals were detected above CVs.

No treatment is currently being performed on any OU 2 sites. The draft RI report for OU 2 was completed in February 1999, and will be followed by the FS report. JPL is evaluating an interim removal action, using soil-vapor extraction to begin removing VOC vapors from soil. No public health hazard is associated with these sites because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard.
Seepage Pit 5 This site is located beneath a lawn and concrete sidewalls east of Building 277. Seepage Pit 5 was associated with former Buildings 68, 71, and 127, which may have been used to store solvents used in mixing and developing propellants. Soil gas: CTC, Freon, and TCE were detected.

Subsurface soil: No SVOCs were detected. No metals were detected above CVs.

See Seepage Pit 1 No public health hazard is associated with this site because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard. This seepage pit is believed to be buried and is unlikely to have contaminated the surface soil of the lawn.
Seepage Pit 6 This seepage pit is located beneath Mariner Road just south of Building 277 and is inaccessible to JPL employees. This seepage pit may have been associated with the same contaminant sources as Seepage Pits 1, 2, 3, 4, and 5. Soil gas: CTC, Freon, and TCE were detected.

Subsurface soil: No SVOCs were detected. No metals were detected above CVs.

See Seepage Pit 1 No public health hazard is associated with this site because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard.
Seepage Pits 7, 7A, and 7B Seepage Pit 7 is located beneath Building 103, and Seepage Pits 7A and 7B are located beneath an electrical substation south of Building 103; these sites are inaccessible to JPL employees. Building 103 housed machine, fabrication, and metal shops; solvents and other liquids were allegedly dumped in a drain hole in the floor (Seepage Pit 7). Soil gas: CTC and TCE were detected.

Subsurface soil: One SVOC was detected below CVs in one soil sample. No metals were detected above CVs.

See Seepage Pit 1 No public health hazard is associated with these sites because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard.
Seepage Pits 8, 9, 13, and 13A Seepage Pits 8, 13, and 13A are located beneath Building 302 and are inaccessible to JPL employees. Seepage Pit 9 is also suspected to be located under Building 302, but its exact location is unknown. Seepage Pit 8 is a dry well the drained liquids from a testing machine. Seepage Pit 9 may have been connected to a small workshop at former Building 13 or to the credit union at former Building 44. Seepage Pits 13 and 13A may have been connected to a materials and/or chemistry laboratory, and drained to Seepage Pit 8. Seepage Pits 8, 13, and 13A were inaccessible to soil probing or boring.

Soil gas: No VOCs were detected at Seepage Pit 9.

See Seepage Pit 1 No public health hazard is associated with these sites because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard.
Seepage Pits 10 and 12 Seepage Pit 10 is located beneath pavement, a retaining wall foundation, and bank of nitrogen tanks east of Building 78. Seepage Pit 12 is located beneath a flower bed and pavement south of Building 78. These sites are inaccessible to JPL employees. Building 78 reportedly housed a hydraulics laboratory and chemical test cell; solvents used for cleaning and degreasing were reportedly dumped into drains. Seepage Pit 10 was inaccessible to soil boring.

Soil gas: Chloroform, CTC, Freon, PCE, and/or TCE were detected at these sites.

Subsurface soil: One SVOC was detected below CVs in one sample from Seepage Pit 12. No metals were detected above CVs in Seepage Pit 12.

See Seepage Pit 1 No public health hazard is associated with these sites because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard.
Seepage Pit 11 Seepage Pit 11 is located beneath a planted slope and a retaining wall foundation north of Building 113. Seepage Pit 11 was associated with former Building 104, which collected sanitary waste, and Building 101, which may have collected solvent and hydrocarbon wastes. Seepage Pit 11 was inaccessible to soil boring.

Soil gas: CTC was detected at this site.

See Seepage Pit 1 No public health hazard is associated with this site because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard. Seepage Pit 11 is believed to be buried and is unlikely to have contaminated the surface soil of the planted slope it is partially beneath.
Seepage Pit 14 This site is located beneath the paved patio entryway to Building 302 and is inaccessible to JPL employees. This seepage pit is associated with the same contamination sources as Seepage Pits 10 and 12. Soil gas: Chloroform, CTC, Freon, and TCE were detected.

Subsurface soil: No SVOCs were detected. No metals were detected above CVs.

See Seepage Pit 1 No public health hazard is associated with this site because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard.
Seepage Pit 15 and 16 Seepage Pit 15 is located beneath the foundation of Building 300, and Seepage Pit 16 is located beneath the north end of the paved patio on the east side of Building 303; these sites are inaccessible to JPL employees. Seepage Pit 15 was associated with old test cell buildings and a liquid testing facility where small spills of solvents reportedly occurred over the years. Seepage Pit 16 may have been used for disposal of paint solvents. Soil gas: CTC, Freon, and TCE were detected.

Subsurface soil: No SVOCs were detected. No metals were detected above CVs.

See Seepage Pit 1 No public health hazard is associated with these sites because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard.
Seepage Pit 17 This site is located beneath a planted slope located near Building 280. The seepage pit was associated with former Building 55, a solid propellant mixing facility where solvents were reportedly disposed of in sumps. Soil gas: CTC, DCE, and Freon were detected.

Subsurface soil: No SVOCs were detected. No metals were detected above CVs.

See Seepage Pit 1 No public health hazard is associated with this site because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard. Seepage Pit 17 is believed to be buried and is unlikely to have contaminated the surface soil of the planted slope it is beneath.
Seepage Pits 18, 19, and 30 Seepage Pit 18 is located beneath Pioneer Road, and Seepage Pit 30 is located beneath a paved parking area off Pioneer road south of Building 117; these sites are inaccessible to JPL employees. Seepage Pit 19 is located beneath Pioneer Road and a planted slope. These seepage pits were associated with a solid propellant test cell where tubs of solvent (e.g., CTC and acetone) were reportedly disposed of in sumps and drains. Sampling at Seepage Pit 18 was performed during a pre-RI investigation.

Soil gas: Freon and DCE were detected at Seepage Pit 19 and Freon and TCE were detected at Seepage Pit 30. No VOCs were detected at these sites.

Subsurface soil: No VOCs were detected in Seepage Pit 18. No SVOCs were detected at Seepage Pits 19 or 30. No metals were detected above CVs in Seepage Pits 18, 19, or 30.

See Seepage Pit 1 No public health hazard is associated with these sites because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard. Seepage Pit 19 is believed to be buried and is unlikely to have contaminated the surface soil of the planted slope it is partially beneath.
Seepage Pits 20 and 21 These sites are located beneath or behind retaining wall foundations and are inaccessible to JPL employees. These seepage pits were associated with compressors and a maintenance shop where solvents were used. These seepage pits were sampled through a single boring.

Soil gas: Chloroform, CTC, DCE, Freon, and TCE were detected.

Subsurface soil: No SVOCs were detected. No metals were detected above CVs.

See Seepage Pit 1 No public health hazard is associated with these sites because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard.
Seepage Pit 22 This site is located beneath office trailers and is inaccessible to JPL employees. This seepage pit is associated with the former wind tunnel building, which had no history of solvent or chemical use. No sampling has been performed at this site. See Seepage Pit 1 No public health hazard is associated with this site because there is no evidence that the site ever contained hazardous materials.
Seepage Pits 23, 24, and 25 Seepage Pits 23 and 24 are located beneath the paved parking area along Explorer Road south of Building 67, and Seepage Pit 25 is located beneath a paved walkway southeast of Building 67; these sites are inaccessible to JPL employees. Although Building 67 has been used primarily as an office building, at one time it did contain small laboratories that may have been connected to seepage pits. Seepage Pit 25 was inaccessible to soil boring.

Soil gas: CTC, DCE, Freon, and TCE were detected at Seepage Pits 23 and 24.

Subsurface soil: One SVOC was detected below CVs in one sample from Seepage Pits 23 and 24. No metals were detected above CVs in Seepage Pits 23 or 24.

See Seepage Pit 1 No public health hazard is associated with these sites because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard.
Seepage Pit 26 and 28 Seepage Pit 26 is located beneath Building 299, and Seepage Pit 28 is located beneath a flower planter and Pioneer Road, south of Building 299; these sites are inaccessible to JPL employees. These seepage pits are associated with Building 299, which housed an experimental chemistry laboratory, fluorine propellant test cell, and acid-neutralizing pit. Numerous chemicals were reportedly disposed of in sumps near the building. Seepage Pit 28 was inaccessible to soil boring.Sampling at Seepage Pit 26 was performed during a pre-RI investigation.

Soil gas: DCE and 1,1,1-TCA were detected at Seepage Pit 26.

Subsurface soil: No VOCs or SVOCs were detected at Seepage Pit 26.

See Seepage Pit 1 No public health hazard is associated with these sites because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard.
Seepage Pit 27 This site is located beneath the paved parking lot southeast of Building 246 and is inaccessible to JPL employees. This seepage pit was connected to a soils test laboratory which had no history of solvent or chemical usage. This site was investigated during the pre-RI investigation. The site was ruled out as suspected contamination source area. See Seepage Pit 1 No public health hazard is associated with this site because there is no evidence that the site ever contained hazardous materials.
Seepage Pits 29 and 31 Seepage Pits 29 and 31 are located beneath paved parking/driveway areas off of Explorer Road and are inaccessible to JPL employees. These seepage pits were associated with solid and liquid propellant test cells where solvents were used. Sampling at Seepage Pit 31 was performed during a pre-RI investigation.

Soil gas: High levels of CTC, as well as chloroform and TCE, were detected at Seepage Pit 31. CTC, Freon, and TCE were detected at Seepage Pit 29.

Subsurface soil: No VOCs were detected at Seepage Pit 31. No SVOCs were detected at these seepage pits. No metals were detected above CVs at these seepage pits.

See Seepage Pit 1 No public health hazard is associated with these sites because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard.
Seepage Pits 32 and 34 Seepage Pit 32 is located beneath a paved walkway south of Building 86, and Seepage Pit 34 is located beneath the paved driveway northeast of Building 98; these sites are inaccessible to JPL employees. These seepage pit were located at the eastern end of a solid propellant preparation area and were reportedly used to dispose of solvents and other chemicals. Seepage Pit 32 was inaccessible to soil boring.

Soil gas: Benzene, toluene, ethylbenzene, and xylene, chloroform, Freon, DCA, DCE, PCE, and 1,1,1-TCA were detected at Seepage Pit 34.

Subsurface soil: No SVOCs were detected at Seepage Pit 34. No metals were detected above CVs in Seepage Pit 34.

See Seepage Pit 1 No public health hazard is associated with these sites because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard.
Seepage Pit 33 This site is located beneath a paved driveway west of Building 97 and is inaccessible to JPL employees. This seepage was associated with a development laboratory for solid propellant chemistry experimentation where solvents were used to clean hardware. All liquids reportedly were drained to the seepage pit. Soil gas: No VOCs were detected.

Subsurface soil: No SVOCs were detected. No metals were detected above CVs.

See Seepage Pit 1 No public health hazard is associated with this site because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard.
OU 2: Contamination Sources (continued)
The following waste pits were used for disposal of municipal wastes and solid and liquid hazardous wastes.
Seepage Pits 36 and 37 Seepage Pit 36 is located beneath a paved driveway, and Seepage Pit 37 is located beneath Explorer Road; these sites are inaccessible to JPL employees. Seepage Pit 36 was associated with test cells and shops along Jato Road. Seepage Pit 37 was a dry well for a former building with an unknown use. Soil gas: Soil-vapor probe detected chloroform and CTC. Soil-vapor well detected CTC, chloroform, TCE, and PCE.

Subsurface soil: No SVOCs were detected. No metals were detected above CVs.

See Seepage Pit 1 No public health hazard is associated with these sites because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard.
Waste Pits WP-1, WP-2, and WP-5 These sites are located along the eastern property boundary just south of Arroyo Road. WP-1 and WP-2 cross over the property boundary into the Arroyo Seco. A soil-vapor probe or monitoring well has not been installed at WP-5.

Soil gas: No VOCs were detected at these waste pits.

Subsurface soil: No SVOCs were detected at WP-1 or WP-2. No metals were detected above CVs at WP-2. No contaminants were detected above CVs at WP-5.

No treatment is currently being performed on any OU 2 sites. The RI report for OU 2 is under review by regulators, and will be followed by the FS report. JPL is considering an interim removal action, using soil-vapor extraction, to begin removing VOC vapors from soil. No public health hazard is associated with these sites because contaminants were detected at levels that do not pose a health hazard. Although JPL employees and recreational users (hikers, horseback riders) could access this area, contamination was not detected at levels that pose a public health hazard.
Waste Pit
WP-3
This site is located underneath a paved area along Pioneer Road southwest of Building 248 and is inaccessible to JPL employees. Soil gas: Chloroform, CTC, Freon, DCE, and TCE were detected.

Subsurface soil: One SVOC was detected below CVs in one sample. No metals were detected above CVs.

See Waste Pit WP-1 No public health hazard is associated with this site because subsurface soils are inaccessible and contaminants were detected at levels that do not pose a health hazard.
OU 2: Contamination Sources (continued)
The following discharge points received stormwater runoff that may have contained hazardous materials.
Waste Pit WP-4 This site is located along the eastern property boundary just south of Arroyo Road. Soil gas: Soil-vapor well detected no VOCs.

Subsurface soil: Polycyclic aromatic hydrocarbons (PAHs) were detected below CVs in one sample. No metals were detected above CVs.

See Waste Pit WP-1 No public health hazard is associated with this site because contaminants were detected at levels that do not pose a health hazard. Although JPL employees and recreational users (hikers, horseback riders) could access this area, contamination was not detected at levels that pose a public health hazard.
Discharge Point DP-1 DP-1 is located approximately 50 feet beyond the eastern property boundary, in the Arroyo Seco. Soil gas: No VOCs were detected.

Subsurface soil: A dioxin, PAHs, polychlorinated biphenyls (PCBs), and SVOCs were detected below CVs.

No treatment is currently being performed on any OU 2 sites. JPL is considering an interim removal action, using soil-vapor extraction, to begin removing VOC vapors from soil. No public health hazard is associated with this site because contaminants were detected at levels that do not pose a health hazard. Although JPL employees and recreational users (hikers, horseback riders) could access this area, contamination was not detected at levels that pose a public health hazard.
Discharge Points DP-2, DP-3, and DP-4 DP-2 and DP-4 are located near the eastern property boundary, while DP-3 is located approximately 150 feet beyond the eastern property boundary, in the Arroyo Seco. Soil boring was performed on DP-2, while test pitting was performed on DP-3 and DP-4.

Soil gas: No VOCs were detected at DP-2.

Subsurface soil: PAHs were detected below CVs at DP-3. No metals were detected above CVs at DP-3 or DP-4.

See DP-1 No public health hazard is associated with these sites because contaminants were detected at levels that do not pose a health hazard. Although JPL employees and recreational users (hikers, horseback riders) could access these areas, contamination was not detected at levels that pose a public health hazard.
OU 2: Contamination Sources (continued)
The following OU 2 sites are locations of miscellaneous suspected chemical releases.
Building 197 This building was suspected to have VOC contamination as a result of wind tunnel and propellant operations. Soil gas: Freon was detected.

Subsurface soil: No SVOCs were detected. No metals were detected above CVs.

No treatment is currently being performed on any OU 2 sites. JPL is considering an interim removal action, using soil-vapor extraction, to begin removing VOC vapors from soil. No public health hazard is associated with this site because no contamination was detected except for low levels of Freon at depth.
Building 302 A contamination source was suspected to be located beneath Building 302, the Micro Devices Building. Building 302 was inaccessible to soil boring. JPL attempted to investigate this source area by performing soil gas probes around the edge of the building.

Soil gas: Soil-vapor probe detected no VOCs.

See Building 197. No public health hazard is associated with this site because there is no completed exposure pathway to the suspected contamination source area. Sampling around the building did not detect contamination, and any contamination located beneath the building is not accessible to JPL employees.
Building 306 During excavation of the foundation for this building, JPL discovered an old landfill. This landfill is believed to predate JPL. Soil in the landfill was contaminated with oil which apparently had been used as a dust suppressor. Soil gas: CTC, Freon, 1,1,1-TCA, and TCE were detected.

Subsurface soil: Subsurface soil samples detected no SVOCs. No metals were detected above CVs.

JPL removed approximately 20,000 cubic yards of contaminated soil. Post-excavation sampling confirmed that the contaminated soil had been removed. No public health hazard is associated with this site because the petroleum-contaminated soil was removed.
OU 3: Off-site Groundwater
City of Pasadena drinking water wells Four drinking water wells are located within 2,500 feet southeast of JPL, just east of the Arroyo Seco. This water source, in combination with imported water, serves approximately 133,000 people in Pasadena. Monitoring of wells in 1980 revealed low concentrations of CTC and TCE that gradually increased over time. Low levels of PCE and other VOCs have also been detected periodically. Perchlorate has been detected above California's action level in two drinking water wells and has been detected below the action level in the two other wells. Two wells were closed in 1985, and two more were closed in 1989 when contaminants exceeded drinking water standards. In 1990, JPL and the city of Pasadena constructed a water treatment plant to remove VOCs from the water and allow the wells to be reopened. The Arroyo Well was closed again in 1997 due to perchlorate contamination. No public health hazard is associated with VOC contamination in these wells. VOCs have been present above drinking water standards in raw water from some of these wells but, due to treatment and blending, the finished water does not contain VOCs above drinking water standards. Since water purveyors sample their groundwater for VOCs periodically rather than continuously, for short periods of time in the past finished drinking water may have contained VOCs above drinking water standards. However, VOCs in these wells have been at low levels that would not have caused adverse health effects to consumers over short periods of exposure.
City of Pasadena drinking water wells (continued)  

CTC, perchlorate, and TCE have been detected above the MCL/action level in raw water from one or more of these supply wells. The ranges of contaminant concentrations detected above the MCL/action level are as follows:

Cont. Range MCL
CTC 5.1 - 13.0 ppb 5 ppb
Perchlorate 90 - 145 ppb 18 ppb
TCE 5.0 - 32.0 ppb 5 ppb
Perchlorate has more recently been detected above the action level in Well No. 52. By blending water from this well with water from the remaining wells, Pasadena is reducing the overall perchlorate concentration of its finished water to below the action level. Pasadena performs monthly sampling at each well for VOCs and perchlorate and performs weekly sampling of its finished water for VOCs and perchlorate. The California Department of Health Services (CDHS) reviews these sampling data. Perchlorate contamination presents an indeterminate past public health hazard because groundwater was not analyzed for perchlorate until 1997. Perchlorate levels may have been lower in the past, because perchlorate levels rose throughout 1997 in the Pasadena wells. Although one Pasadena well had perchlorate levels above the action level when perchlorate analysis began, the other three wells did not exceed the action level, so the blended finished water probably did not exceed the action level. Through regular sampling and well water blending, Pasadena is currently able to keep the perchlorate concentration below the action level in its finished water.
Lincoln Avenue Water Company drinking water wells Two drinking water wells are located within 3,500 feet southeast of JPL, in Altadena. This water source serves approximately 8,000 people, primarily in Altadena. Monitoring of wells revealed CTC, PCE, and TCE in both drinking water wells in the early 1980s that gradually increased over time. Perchlorate has been detected below California's action level in these wells.

PCE and TCE have been detected above the MCL in raw water from one or more of these supply wells. The ranges of contaminant concentrations detected above the MCL are as follows:

Cont. Range MCL
PCE 6.9 ppb* 5 ppb
TCE 5.9 - 92 ppb 5 ppb

* Only one detection was above the MCL.

These two wells were shut down in 1987 when concentrations of TCE exceeded drinking water standards. In 1992, Lincoln Avenue installed a granular activated carbon treatment system and was able to reopen its wells. Through a combination of treatment, blending, and the addition of imported water, Lincoln Avenue has kept its finished water within regulatory standards. Lincoln Avenue performs weekly sampling of its raw and finished water for VOCs and perchlorate. CDHS reviews these sampling data. No public health hazard is associated with VOC contamination in these wells. VOCs have been present above drinking water standards in raw water from some of these wells but, due to treatment and blending, the finished water does not contain VOCs above drinking water standards. Since water purveyors sample their groundwater for VOCs periodically rather than continuously, for short periods of time in the past finished drinking water may have contained VOCs above drinking water standards. However, VOCs in these wells have been at low levels that would not have caused adverse health effects to consumers over short periods of exposure.

* Perchlorate contamination presents an indeterminate past public health hazard because groundwater was not analyzed for perchlorate until 1997. In light of the current low levels of perchlorate in these wells, however, it is unlikely that past exposure to perchlorate presents a public health hazard.
Valley Water Company drinking water wells Four drinking water wells are located within 2,500 feet west of JPL. This water source, in combination with imported water, serves approximately 10,500 people in La Cañada-Flintridge. Valley Water uses groundwater only from May through September; for the rest of the year the company relies on imported water. Although JPL is generally downgradient to the wells, increased rainfall and groundwater mounding in the Arroyo Seco can reverse groundwater flow from JPL towards these wells for short periods of time. PCE and TCE were discovered above drinking water standards through monitoring in the 1985. Perchlorate has been detected below California's action level in these wells.

PCE and TCE have been detected above the MCL in raw water from one or more of these supply wells. The ranges of contaminant concentrations detected above the MCL are as follows:

Cont. Range MCL
PCE 52 - 110.0 ppb 5 ppb
TCE 5.9 ppb* 5 ppb

* Only one detection was above the MCL.

Valley Water installed an air stripper system in 1993 to treat VOCs. Through a combination of treatment, blending, and the addition of imported water, Valley Water has kept its finished water within regulatory standards. During its groundwater pumping season, Valley Water performs monthly sampling of raw water for VOCs and perchlorate and performs weekly sampling of its finished water for VOCs. CDHS reviews these sampling data. No public health hazard is associated with VOC contamination in these wells. VOCs have been present above drinking water standards in raw water from some of these wells but, due to treatment and blending, the finished water does not contain VOCs above drinking water standards. Since water purveyors sample their groundwater for VOCs periodically rather than continuously, for short periods of time in the past finished drinking water may have contained VOCs above drinking water standards. However, VOCs in these wells have been at low levels that would not have caused adverse health effects to consumers over short periods of exposure.

* See Lincoln Avenue Water Company.
La Cañada Irrigation District drinking Water wells Two drinking water wells are located within 3,000 feet west of JPL. This water source, in combination with imported water, has in the past served approximately 8,500 people in La Cañada-Flintridge. These wells had been inactive for some time but were reopened in 1997. Although JPL is generally downgradient to these wells, increased rainfall and mounding in the Arroyo Seco can reverse groundwater flow from JPL towards these wells for short periods of time. Perchlorate has been detected at concentrations below California's action level. With one exception, any VOCs detected in these wells have been at concentrations below drinking water standards; VOCs temporarily exceeded water standards in one sampling round, but subsequent samples showed contamination had fallen back to below the standards. Nitrate levels have been elevated but below drinking water standards. La Cañada currently performs yearly sampling of its raw water for VOCs and quarterly sampling for nitrates. CDHS reviews these sampling data. La Cañada has also performed some perchlorate sampling. Because the samples of raw water have met water quality standards, CDHS does not require La Cañada to sample its finished water. As La Cañada begins its injection/recovery program and becomes a larger water producer, CDHS may require a different sampling schedule. No public health hazard is associated with these drinking water wells. No contaminants have been detected in water from these wells at levels above drinking water standards.

* See Lincoln Avenue Water Company.

Rubio Canyon Land and Water Company drinking water wells Two drinking water wells are located approximately 1 mile southeast of JPL, in Pasadena. This water source, in combination with imported water, serves approximately 7,350 people. Perchlorate has been detected at concentrations below California's action level. Organic contaminants were detected below drinking water standards in one well in 1989 but have not been detected in later samples. Rubio Canyon conducts yearly sampling of its raw water for VOCs, and perchlorate sampling when requested by CDHS. CDHS reviews these sampling data. Because no contaminants have been detected above drinking water standards in raw water samples, CDHS does not require Rubio Canyon to sample its finished water. No public health hazard is associated with these drinking water wells. No contaminants have been detected in water from these wells at levels above drinking water standards.

* See Lincoln Avenue Water Company.

Los Flores Water Company drinking water wells One drinking water well is located over 1 mile southeast of JPL, in Pasadena. This water source, in combination with imported water, serves approximately 2,800 people. Los Flores imports water throughout the year, and pumps groundwater only during months of peak demand (usually May to November). PCE has recently been detected (4.7 ppb) near the federal MCL in the drinking water well. The source of the PCE has not yet been determined. Perchlorate has been detected below the action level. Due to the recent detection of PCE, Los Flores plans to perform quarterly sampling of its raw water for VOCs (CDHS has not yet assigned Los Flores an updated sampling schedule.) During well operations, Los Flores will also take monthly or bimonthly perchlorate samples, although CDHS has not required this sampling. Because the samples of raw water have met water quality standards, CDHS has not required Los Flores to sample its finished water. Due to the recent PCE detection, however, Los Flores may voluntarily sample its finished water during the next pumping season. No public health hazard is associated with these drinking water wells. No contaminants have been detected in water from these wells at levels above drinking water standards.

* See Lincoln Avenue Water Company.

1 Samples of surface soil (0 to 6 inches deep) generally were not collected at JPL because most of the suspected source areas are buried beneath pavement, buildings, retaining walls, or flower planters. At areas that are exposed at the surface (e.g., the stormwater discharge points), soil sampling began at depths of 1 foot or more. For these areas, ATSDR considered the shallowest samples to be representative of surface soil.
Sources (OU 1): Foster Wheeler, 1997a, 1997b., 1999b
Sources (OU 2): Ebasco, 1990a, 1993; Foster Wheeler, 1997c, 1998a.
Sources (OU 3): City of Pasadena, 1998; JPL, 1997d; La Cañada, 1998; Lincoln Avenue, 1998; Los Flores, 1998; Raymond Basin, 1997a, 1997b; Rubio Canyon, 1998; Valley Water, 1998; Foster Wheeler, 1999b.

Table 2.

Exposure Pathways
Pathway Name Exposure Pathway Elements Comments
Source of Contamination Environmental Medium Point of Exposure Route of Exposure Time of Exposure Exposed Population
Completed Exposure Pathways
Off-site groundwater: Perchlorate contamination Contaminated soil and groundwater at JPL. Groundwater Drinking water pumped from aquifers near JPL. Ingestion
Dermal contact
Inhalation
Past: Perchlorate in groundwater was not analyzed before 1997.

Present and future: Perchlorate has been detected at low levels in most of the drinking water wells in the vicinity of JPL. Perchlorate levels exceed California's action level in some wells, which have been either closed down or blended with water from other wells.

Customers of drinking water purveyors located in the vicinity of JPL. Perchlorate contamination in off-site groundwater presents no apparent present or future public health hazard. The current sampling and blending procedures used by the drinking water purveyors near JPL are expected to prevent any potential present or future public health hazards posed by perchlorate in groundwater. Past exposures to perchlorate contamination present an indeterminate public health hazard because there are no data on perchlorate levels before 1997. Based on the available data, however, it is unlikely that past perchlorate levels in groundwater have posed a public health hazard.
Potential Exposure Pathways
Off-site groundwater: VOCs contamination Contaminated soil and groundwater at JPL; other off-site sources may also exist. Groundwater Drinking water pumped from aquifers near JPL. Ingestion
Dermal contact
Inhalation
Past, present, and future: VOCs have been detected in various drinking water wells since the early 1980s. Customers of water purveyors located in the vicinity of JPL. VOC contamination in off-site groundwater does not present a past, present, or future public health hazard because water purveyors, under the supervision of CDHS, have regularly monitored drinking water wells and taken steps (e.g., water blending, water treatment, or well closure) to ensure that the water distributed to consumers is safe. For all purveyors VOCs have been at low levels that would not have caused adverse health effects to consumers over short periods of exposure.
On-site soil Historical disposal of hazardous wastes to on-site seepage pits, waste pits, and stormwater discharge points; miscellaneous spills and chemical releases. Surface and subsurface soil Surface soils beneath grass and other vegetation; subsurface soils exposed through const-ruction. Ingestion
Dermal contact
Past: Source areas now covered by pavement, buildings, etc. may have been accessible in the past.

Present and future: Several seepage pits are located in areas covered with grass or other vegetation. The depths of these seepage pits beneath the surface are not known in all cases, but it is unlikely that any of them are located at the surface.

JPL employees and construction workers Contaminated soils at JPL do not present a public health hazard because these soils do not contain contaminants at levels that pose a public health hazard and/or they are inaccessible to JPL workers. Although workers could be exposed to currently inaccessible subsurface soils during future excavation, demolition, or construction work, ATSDR assumes that these workers will wear proper protective equipment in accordance with OSHA regulations.
On-site VOC vapors Historical disposal of VOCs to on-site seepage pits. Indoor air Basements/lower levels of buildings near contaminated soil. Inhalation Past: VOC vapors were detected at relatively shallow depths in soil-vapor probes 31 and 33, located near Building 107. There are no data on past indoor air quality in this building.

Present and future: Air quality samples taken in May 1998 showed that there were no VOC vapors in Building 107.

JPL employees in affected buildings. No public health hazard is associated with indoor VOC vapors because recent sampling indicated that VOC vapors are not present in Building 107.
Off-site soil Historical disposal of hazardous wastes to waste pits and stormwater discharge points. Surface and subsurface soil Waste pits (WP-1, WP-2, and WP-4) that extend over the property boundary into the Arroyo Seco; off-site stormwater discharge points (DP-1 and DP-3) in the Arroyo Seco. Ingestion
Dermal contact
Past, present, and future: Any exposure to contaminated soil through recreational use at these sites is likely to be infrequent and of short duration. Hikers, horseback riders, and others who use the Arroyo Seco for recreation. No public health hazard is associated with off-site soil because contaminants were detected at levels that do not pose a health hazard. Although JPL employees and recreational users (hikers, horseback riders) could access these areas, contamination was not detected at levels that pose a public health hazard.

Table 3.

Summary of Raw Water Data from Water Purveyors in the Vicinity of JPL
Contaminant Range of Detections by Well (ppb)1 Date of First Detection Comparison Values (ppb) Comparison Value Reference
City of Pasadena (Data from 1/80 - 6/93, 10/96-9/97)
Chemical Well No.52 Arroyo Ventura Windsor      
CTC 0.4 - 2.7 0.6 - 13 0.1 - 1.0 0.4 - 5.1 5.1 (6/89) 5
7
MCL
child RMEG
TCE 0.3 - 5.6 1.2 - 32 0.1 - 1.0 0.9 - 3.6 1.4 (6/89) 5 MCL
Perchlorate 10 90 - 130 4.0 - 5.0 nd 90 (8/97) 18 CDHS Action Level (AL)
Lincoln Avenue Water Company (Data from 1/80 - 11/96)
  Well 3 Well 5          
PCE 0.1 - 4.1 0.67 - 6.9     0.67 (7/81) 5
100
MCL
child RMEG
TCE 0.2 - 72 3.8 - 92     10.1 (1/80) 5 MCL
CTC 0.3 - 2.0 0.6 - 1.9     2.0 (12/90) 5
7
MCL
child RMEG
Perchlorate 7.0 - 17 6.0 - 7.0     7.0 (6/97) 18 CDHS AL
Valley Water Company (Data from 12/81 - 9/84, 6/85 - 3/94)
  Well 1 Well 2 Well 4 Well 3      
PCE

2.5 - 63.8

32 6.2 - 110 0.9 - 2.0

32 (6/85)

5
100

MCL
child RMEG

TCE

0.6 - 5.9

1.0 0.6 - 4.6  

5.9 (6/85)

5

MCL
Perchlorate 5.0 3.1 - 4.0 5.0 3.2 -4.4 5.0 (6/97) 18
CDHS AL
Rubio Canyon Land and Water Co. (Data from Foster Wheeler, 1999b)
  Well #4 Well #7          
Perchlorate 5.0 - 6.0 4.0     06/97 18 CDHS AL
Las Flores Water Co, (Data from Foster Wheeler, 1999b)
  Well # 2            
Perchlorate 5.0 - 7.0       06/97 18 CDHS AL

Source: City of Pasadena, 1998; Lincoln Avenue, 1998a; Valley Water, 1998a, 1998b, Foster Wheeler, 1999b.

1 All sampling data are of raw water (before water treatment) from the wellhead, where a contaminant exceeded a comparison value, except for a few Pasadena samples of blended water.

Key: MCL = EPA's maximum contaminant level; RMEG= ATSDR's reference dose media evaluation guide; CDHS=California Department of Health Services.

Table 4.

Sources of Drinking Water for Water Purveyors in the Vicinity of JPL
Water Purveyor Public Drinking Water Wells Near JPL Date of Operations Well Water Blending Water Treatment % of Local Groundwater /
% of Imported Water
Source of Imported Water Year Imported Water First Used
City of Pasadena Windsor 1918 - present 1 Water from four wells is blended in a reservoir before use. Water treatment plant since September 1990.

40%/ 60%

MWDSC
(50% from Colorado River and 50% from Northern California)

1954

Ventura 1924 - present 1
Arroyo 1930 - 1997
Well 52 1977 - present 1
Lincoln Avenue Water Company Well 3 1920 - present 2 Well water is not blended because wells are operated one at a time. Water treatment plant since 1992.

80%/ 20%

same same
Well 5 1971- present 2
Valley Water Company Well 1 1914 - present Well water, which is used only during the summer months, is not blended routinely because wells are operated one at a time. Air stripping unit since 1994.

25-30%/
70-75%

same same
Well 2 1921 - present
Well 4 1971 - present

Sources: Lincoln Avenue, 1998b; JPL, 1994; Valley Water, 1999.
1 Elevated contaminant concentrations forced the temporary closure of two Pasadena municipal wells in 1985, followed by the temporary closure of the remaining two Pasadena wells in 1989. All four wells reopened in 1990 following the start up of the water treatment plant. Lincoln Avenue Water Company closed their two wells in 1987 due to contamination, but they reopened the wells in 1992 when the water treatment plant went on line.

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