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1. ATSDR > Public Health Assessments & Consultations

PUBLIC HEALTH ASSESSMENT

NAVAL STATION TREASURE ISLAND
HUNTERS POINT ANNEX
SAN FRANCISCO COUNTY, CALIFORNIA

ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

Introduction

ATSDR has evaluated contaminants discussed in subsequent sections of this public health assessment to determine whether exposure to them has public health significance. To select contaminants for discussion, ATSDR considers several factors: sampling design, field and laboratory data quality, contaminant concentrations compared with health-based values, and community health concerns.

Evaluating sampling design included reviewing the base's approach to locating contamination. Spatial distribution of sampling locations, sampling frequency, concentration changes over time, medium-to-medium differences, and correlation between the selected list of analytic parameters and suspected environmental contaminants are the factors ATSDR considered when determining the contaminants to which people might be exposed.

ATSDR's review of sampling field quality control procedures included interpreting data on background (or regional) concentrations of contaminants. Additionally, the adequacy and number of replicate, spiked, and blank samples were checked to verify detection of contaminants. To assess laboratory quality control, ATSDR reviewed procedures used to verify instrument reliability.

Chemical concentrations detected on and off site were compared to values representing exposures believed to be without adverse health effects. Those comparison values are typically derived from data from animal studies and occupational exposures. The severity of health effects depends not only on exposure dose, but on the route of exposure (entry into the body) and on the amount of chemical absorbed by the body. For those reasons, comparison values used in public health assessments are contaminant concentrations in specific media and for specific exposure routes. Several comparison values may be developed for a specific contaminant.

The following assumptions were used to calculate comparison values (EMEG, CREG, iEMEG, RMEG, and RfDC) used in this public health assessment:

To protect the most sensitive segments of exposed populations, ATSDR generally selects the comparison value calculated from the most protective exposure assumptions. The potential for people to experience adverse health effects following exposure to contaminants at levels of health concern is discussed in the Public Health Implications section of this document.

Background levels in local soil and water may be greatly influenced by high levels of chemicals from native mineral deposits or other natural sources. Background levels could be anthropogenic (e.g., gravel for a road or parking lot) substances in the environment due to human-made, non-site sources. If the concentrations of contaminants exceed background levels, ATSDR will evaluate if exposure to those contaminants is of public health concern.

ATSDR also evaluates radioactive contamination. The Agency's approach to evaluating radionuclides and other radioactive materials differs from its evaluation of nonradioactive hazardous materials. Because of the additive effects of radiation on the human body, the dose from radionuclide or radioactive materials is calculated for all exposure routes. Once the doses by various routes are determined; a total dose is calculated.

The annual limit on intake, as defined by the International Commission on Radiation Protection (ICRP), is the amount of a single radionuclide and its progeny that delivers the occupational effective-dose limit by way of ingestion or inhalation. Occupational annual limit of intake are calculated using the average career span of an occupationally exposed person -- 50 years. To address public exposures, ICRP recommends using the average lifetime of an individual (70 years), and the public's effective-dose limit, 1 mSv (100 mrem) per year, to determine the public's limit of intake. A glossary of the terms describing the contaminants of concern, health comparison values, and the radiological terms used in this section of the public health assessment are in Appendix A.

In the data tables describing the contaminants of concern at HPA, the listing of a contaminant does not mean that exposure to it will cause adverse health effects. Rather, the list indicates which contaminants exceeded comparison values and its presence in all media will be discussed. Multiple routes and multiple chemical effects will be evaluated. Most of the comparison values in this document are calculated using adult ingestion rates and body weights because most of the areas under investigation are visited by adults. Comparison values for children are lower than those for adults. ATSDR uses the lower comparison values when children at a site could be exposed to contaminants in a specific medium.

A. On-Site Contamination

Contamination in soil, sediment, air, groundwater, surface water, and food chain as well as other hazards will be discussed in this section. All on-site sampling has been conducted by the Navy.

Radiation

Historically, many HPA areas have received shipyard and repair wastes such as discarded radium dials and sandblast wastes. A preliminary radiation survey was conducted in 1988 to determine if there was elevated radioactivity at HPA. The Industrial Landfill, Bay Fill Area, Oil Reclamation Ponds and the Sub-Base Area were surveyed for evidence of gross gamma radioactivity. That information was not evaluated during preparation of this public health assessment because more recent and more comprehensive data were available. A radiation overview can be found in Appendix E.

In 1992, the Surface Confirmation Radiation Survey (SCRS) was conducted to evaluate sources of possible radioactive contamination at the Industrial Landfill, Bay Fill Area, Oil Reclamation Ponds, the Officers Club, the Oily Liquid Waste Disposal Area, the Oily Waste Pond and Incineration Tank, and the Sub-Base Area (Figure B-2). Low-level radioactive waste which is defined in 10 CFR 61.2 was primarily disposed of at the landfill areas. Potential sources of radiation at the Industrial Landfill and Bay Fill areas include crushed radium sources and black sand (Black Beauty) non-indigenous to HPA containing elevated natural radiation. The radium sources are in the form of:

dime-sized, sealed, glass discs with a spot of radium in the middle (51);
ceramic/glass wafers;
hollow ferrous discs with a glass covers;
quarter-sized metal sources with back plates;
disintegrated radium sources.

Those components and parts, containing radioactive radium, were not designed or made to prevent the release of the radioactive material. The radium was incorporated into luminous dials, numbers and pointers of watches and compasses. Other radium parts were made into markers, lines, and spots that glowed in the dark (52). Those radium sources were deposited at the Industrial Landfill and Bay Fill areas after WWII. Some of the sources at the landfills were crushed or decomposed, allowing radioactive materials to escape into the environment (4). A radium/radon fact sheet is in Appendix F.

Radionuclides in Soil

Soil samples were collected to establish the amount and type of radionuclides at areas on base and to establish background levels. Soil samples were taken in areas with elevated gamma levels and in non-anomalous locations. Non-anomalous soil samples were taken to determine background levels of radionuclides.

The Navy performed a gamma radiation meter survey to locate gamma-emitting point sources on the soil surface and up to 12 inches below the ground surface. Up to 500 radium sources were detected at or near the surface, i.e., within the first 12 inches of the soil at IR-1 and IR-2. Once a gamma source or an anomaly (higher than the expected background gamma reading) was found, the location was marked in the field.

Figure B-4 shows the locations used for the establishment of background gamma activity. Background samples were collected at non-disposal sites.

Ten percent of the samples collected were analyzed for plutonium. A total of 120 soil samples (not including background samples) were collected during the SCRS. Soil sample analysis indicated the presence of americium-241 (Am-241), cesium-137 (Cs-137), potassium-40 (K-40), radium-226 (Ra-226), radium-228 (Ra-228), thorium-228 (Th-228), plutonium-238 (Pu-238), plutonium-239 (Pu-239), and plutonium-240 (Pu-240).

Figure 1 shows soil background ranges for Am-241, Cs-137, Ra-226, Ra-228, and Th-228 found at HPA.

The probability and severity of health effects increases as exposure to radiation increases, although exposure to background levels of radiation (i.e., those levels naturally occurring in the environment) are thought not to produce noticeable health effects in humans (54). Thus for radiation protection purposes, the dose due to radiation exposures above background is calculated as an indicator of potential health effects.

Because exposures to radiation levels above background are indicators of potential health effects, the natural background concentrations in nearby, representative soils are first established and then compared to soil concentrations found in contaminated areas. To accomplish that, ATSDR constructed a histogram of the radiation levels found in HPA soils. The histogram (Figure 2) shows the distribution of radiation levels found in HPA soils relative to background.

Figure 2 shows the number of soil samples from anomalous areas which were within the ranges of background, between one and two times background, between two and three times background, between three and four times background, between four and five times background, and more than five times background.

A comparison between background radium concentrations and concentrations in anomalous areas suggest that, for some areas (e.g., IR-1/21 and IR-2) anomalous area radium concentrations exceeded those of background. Background concentration for Ra-226 ranged from 0.11 to 1.13 pCi/gram, with an average of 0.64 pCi/gram. For the isotope of greatest concern, Ra-226, most of the contamination was found at IR-2, the Bay Fill Area (Figures B-5 and B-6). A large area 600 feet by 600 feet with numerous point source anomalies was identified within the area. The highest concentration of Ra-226 detected at IR-2 was 3,905 pCi/gram, which was associated directly with a dial face. Several radium sources were also found at the IR-1/21 (Figure B-7), the Industrial Landfill, which is located next to IR-2.

The EPA National Air and Radiation Environmental Laboratory (NAREL) has proposed using volume reduction/chemical extraction (VORCE) technology to remediate IR-1/21 and IR-2. On October 4, 1993, EPA discussed preliminary results of Phase I of the pilot remediation project. During the first phase, three soil samples were collected from HPA for petrographic analysis. Analysis was performed to determine which soil fraction was associated with the Ra-226. Of the three samples that were collected, one of the samples had 100 percent recovery, which means that no Ra-226 was found in the soil sample when the point source was physically removed from the sample. The two other samples yielded an approximate 30 percent recovery; most of the Ra-226 remained in the sample after the source was removed. This remaining activity is considered to be diffuse contamination. Therefore, NAREL still needs to determine the amount of diffuse material that may remain in the landfill after a point source is removed (53).

The Navy is conducting a phase II and a phase III radiation investigation. Additional trenching and sampling of soil within IR-1, IR-2, IR-7, and IR-18 have taken place to determine the subsurface extent of radioactive contamination. Air permeability of soils has been tested at IR-1, IR-2, and IR-7. A surface radiation contamination survey of buildings previously used by NRDL and of other buildings suspected of having been used for radiologic operations will be conducted. Gamma logging was conducted inside the casings of existing monitoring wells. Gamma logging was used to evaluate the vertical extent of the gamma-emitting Ra-226 contamination in the surrounding soil. Investigation-derived cuttings and archived soil samples in Buildings 810 and 414 are being screened for field gamma radioactivity (5).

Radiation in Air

The Navy tested IR-1, IR-2, and IR-5, and in the surrounding areas, on and off site, for gross alpha and beta radiation in air. The investigation indicated that the amount of alpha and beta radiation in the air at these areas were typical of background levels in the area. Therefore, the americium, radium, thorium, cesium, and plutonium in undisturbed soils at those areas do not appear to be escaping into the ambient air (55).

Because Ra-226 may be a problem, ATSDR evaluated radon, the decay product of Ra-226. The SCRS tested radium contaminated areas for release of radon into the air. Radon fluxes (measurements of the radon release rates over an area) were measured at the soil/air boundary to accurately determine the boundaries of radium contaminated areas. Radon release rates were determined using carbon filled radon flux canisters. Canisters were placed at random locations, and at locations directly over point sources of gamma activity to identify the boundaries of areas which contained the elevated gamma readings. A total of 371 radon flux canisters were placed around the site.

Background radon emission rates ranged from 0.00 to 1.12 pCi/m²/sec while radon emission rates in anomalous areas ranged from 0.00 to 74.96 pCi/m²/sec. A comparison between background radon emission rates and anomalous area radon emission rates suggest that, in general, anomalous area radon release rates are the same as background release rates (Figure 3).

Data from Figure 3 shows that 0.3% of the radon samples taken in anomalous areas were above the background range. Even though the highest emission rate was 74.96 pCi/m²/sec, the average release rate over the disposal area is less than the Health and Environmental Protection Standard for Uranium and Thorium Mill Tailings (40 CFR 192), 20 pCi/m²/sec. This standard is based on radon released in buildings or homes with children living in them (56). The release rates of the site are not large enough to raise the ambient concentration of radon by measurable amounts in areas where people are present. Overall, radon release rates are the same as background release rates.

Radiation in Ground and Surface Waters

Groundwater was tested for gross alpha and beta radiation. Nine groundwater and two bay water samples were taken. The results of the testing were inconclusive (57).

During the SCRS, downhole gamma radiation surveys were performed in nine monitoring wells to determine the depth of radium contamination (58). The wells were chosen based on their proximity to anomalies and previous sampling results which showed evidence of elevated alpha radiation in water. Results of the survey did not indicate the depth of the contamination and analyses are currently being repeated.

Other Radiological Hazards

Table C-2 lists the NRDL buildings that will be investigated in phase II and III of the radiation investigation (5). During the Navy Fence-to-Fence Radiation Survey, several radiation measurements above normal background were detected on HPA. During a radiation survey, Navy contractors detected a radiation measurement higher than normal background at Building 364, a former NRDL site. The interior of Building 364 was decontaminated, but contamination was detected at the exterior of the building. The area was fenced to limit unauthorized access. The exterior or Building 364 is to be investigated as a part of the phase III radiological investigation. Building 364 was accepted by the NRC for unrestricted use and is presently leased (6). Sampling was conducted inside Building 364; no radiation levels greater than background was found. According to the Navy, the tenant is aware of the elevated radiation levels on the outside foundation. Building 364, has two abandoned, concrete lined utility trenches leading from the rear eastern wall to a nearby covered sump. One of the trenches has a small area that is contaminated with alpha and gamma emitters. The area behind Building 364 is fenced. Remnant radiation was also detected on a portion of the asphalt-covered parking lot area adjacent to Building 364. The radioisotope has been identified as Cs-137.

A combination safe measuring 18 inches by 18 inches located within the fenced Building 414 (IR-14), the low-level radiation waste storage area, contains alpha and gamma activity above release guidelines established by the NRC. The combination safe dial and handle have fixed alpha activity 59,000 dpm/100 cm² . The contents of the safe, previous location, and use are unknown. The safe has remained unopened; the combination is unknown. Tritium was used as a particle accelerator target at Building 816 in Parcel A (59). Sampling for tritium has been completed and none was found (35, 36).

Surface Soil

Industrial Landfill (IR-1/21) and Bay Fill (IR-2)/OU I

In 1993, additional soil sampling took place at OU I (60). VOCs, SVOCs, oil and grease, petroleum hydrocarbons, PCBs, and pesticides were detected sporadically in the artificial fill and displayed non-point source-related characteristics. Antimony, arsenic, copper, lead, and zinc were detected above the interim ambient levels for sepentinite fill and may be point source related (Tables 3 and 4). Interim ambient levels were developed by the Navy, and agreed upon by the agencies, as field screening criteria to identify "hot spots" or high levels of chemical constituents (40).

At IR-1/21, organic compounds and metals were found mostly in a debris zone, which is an area approximately 900 by 1100 feet and found in the central part of IR-1/21 (61). The debris zone is heterogenic in it makes up. According to the Navy, there is no vertical or lateral consistency or pattern to the distribution of these compounds in the debris zone and high concentrations were common. There are three other areas with elevated concentrations of contaminants: along the southwest boundary of the site between 4 and 18 feet; along the east and southeast sides of the landfill to a depth of 5 feet; and in the western central portion of the site adjacent to the bay, highest concentrations generally occurred in soil shallower than 6 feet below ground surface. Triple A reportedly disposed of sandblast waste in this area.

IR-2 was divided into six areas corresponding with Triple A use areas:

Triple A Sites 2 and 14/IR-2. Organic contaminants and metals were detected in shallow and deep soils in an area extending approximately 600 feet to the southeast and 200 feet to the north and northeast for some compounds. Aroclor-1260 and carcinogenic PAHs were observed in soil above 4 feet and appear to be continuous with similar contaminants observed in the southeast corner of IR-1/21. Maximum concentrations were higher in deeper soils. Elevated concentrations extend to a depth of 6 to 12 feet, depending on the bay mud (i.e., 6 to 7 feet).

Triple A Site 19/IR-2. Organic contaminants were detected in a shallow and deep soils. All organic contamination was restricted to the artificial fill layer. Most metals were detected in deep soil between 6 and 11 feet. Approximately 200 feet southeast of Triple A Site 19, elevated levels of metals were detected near Building 600. Boring logs indicate that the elevated concentrations are in a zone of fill that appears to be dredge materials.

Triple A Site 18/IR-2. Aroclor-1260 and petroleum products were detected from the ground surface to a depth of about 6 feet at the east end of Triple A Site 18. At the west end of the area, petroleum products and PAHs were observed in a test pit sample. In two surface soil grab samples, taken behind the backstop of the pistol range in debris piles Aroclor-1260 and carcinogenic PAHs, arsenic, copper, lead, and zinc were detected. Metals were found across Triple A Site 18 in shallow soils.

Triple A Sites 17/IR-2 and IR-3. Organic compounds and metals were detected in both shallow and deep soils. Organic contaminants include xylenes, ethylbenzene, Aroclor-1260, oil, petroleum, and carcinogenic PAHs. Metals include arsenic, copper, lead, and zinc. Organic contamination was significantly higher, as much as one to two orders of magnitude in deep soil than in shallow soil. The difference may be the result of free phase petroleum product floating on the groundwater and residual product present in the soil between 6 and 25 feet bgs (60). Metals were widely distributed across Triple A Site 17.

Triple A Site 13/IR-2. Within the area adjacent to Tank S-505, petroleum products and oil were detected in shallow soil at one location, and in deep soil up to 6 feet bgs at two locations. Lead was detected in shallow soil; copper, lead, and zinc were detected in deep soils. In the area of Triple A Site 13, Aroclor-1260 and carcinogenic PAHs were detected in deep soil. Metal contamination was wide spread.

Southeast End/IR-2. This area may correspond to a burn area, or it may be that this land area of IR-2 was created by pushing the remains of the burned debris into the bay (60). PAHs and metals were found in shallow soil. Carcinogenic PAH contamination is widespread. Metals in deep soil generally appear to be limited to a smaller area than in shallow soil. Dredge spoils may have been deposited of in this area (60). The source of the dredge spoils are assumed to be the San Francisco Bay, location was not specified in Navy documentation.

Off-Site Surface Soil

Railroad Right-Of-Way (PA-52)

Lead (14,267 ppm), copper (24,373.5 ppm), and zinc (580.2 ppm) were detected in off-site surface soil along the railroad right-of-way. Aroclor-1260 (0.180 ppm) and several tentatively identified compounds were also detected (25).

Air

Ambient Air

In 1984, during the Initial Assessment Study, 400 to 500 pounds of discarded waste asbestos were found on the ground immediately outside of Building 521 in Parcel E. Friable asbestos from deteriorating insulation on boilers and other equipment was also found. Some of this asbestos may have been washed away with rainwater (62). Two 8-hour, ambient air samples were taken downwind of Building 521. Samples were analyzed for asbestos fibers; however, asbestos was not detected. Wind speeds during sampling were from 5 to 10 miles per hour.

The Navy conducted a risk assessment in 1987 for the proposed Housing Sites 1 and 2 in Parcel A because they were considering home porting the USS Missouri at HPA. Air samples collected over 8 hours were analyzed for metals, asbestos, and organic compounds at areas which include the following: an area north of Crisp Ave, adjacent to the Industrial Landfill; an area southeast of Donahue Street near the main gate; and an upwind background area. Several VOCs were detected at all sampling locations and asbestos at 0.018 fiber/m³ was detected at only one sampling location. An average of 2-300 fibers/m³ are usually present in urban air. These asbestos levels are sufficiently low that they are not likely to be of significant health concern. All of the Navy's asbestos samples were analyzed by the transmission electron microscopy method.

Most recently, an air sampling screening study for volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), formaldehyde, and asbestos was conducted as part of the RI/FS between July 8-18, 1991. Results of this study were used to develop further recommendations for subsequent base air sampling (62). Ambient air sampling conducted thus far was based on the 11 original IR areas designated in the Confirmation Study (Figure B-8) plus five additional areas.

Sample locations were chosen based on observed prevailing wind conditions on the day of sampling. Prevailing winds would transport emissions and airborne particles predominately to the east-southeast out across the base to the bay (62). Twelve sampling stations were placed directly over, adjacent to, or downwind of the original 11 IR areas (Figure B-8). Table 5 shows location number and the description of were the air sampling stations were located. Station A8 was placed on the downwind perimeter of the base to intercept any airborne contaminants that might originate from other on-site sources. Stations 11 and 12 were placed upwind of HPA to determine background concentrations. According to the Navy, although not within an IR boundary, the area on which Station 11 was located is suspected of containing contaminants similar to those found at IR-1/21 (62). Station 9, located east of the Pickling and Plating Yard, was not placed downwind of interfering sources. The Navy thought that base tenants (artists) near IR-9 may release various airborne contaminants, thereby interfering with the ambient air monitoring. All other samplers were placed downwind of potentially interfering sources (62).

Four samples were taken at each air sampling station (Figure B-8) over a 5-day period and were analyzed for VOCs, SVOCs, PCBs, metals, asbestos, and formaldehyde. Samples were collected for 8 hours. VOCs and SVOCs were monitored at 3 to 6 feet above ground surface. Metals were monitored approximately 3 feet above the ground. Formaldehyde and asbestos were monitored at 5 feet (62). Table 6 shows the contaminants found in air. Sampling procedures are described in the Draft Final Air Sampling Report (62).

Pesticides and metals were detected in air samples (Table 6). Pesticides were detected at concentrations above comparison values at the western boundary of the base at a designated upwind background air monitoring station. The source of the pesticides is unknown. Asbestos was detected at low levels (0.000002 fibers/m³).

During the installation air monitoring study, some of the ambient air samplers were not located in areas that were directly downwind of suspected emission sources associated with the IR areas. In addition, some sites of concern had not been identified at the time the initial study was conducted. To better characterize HPA air quality, the Navy is planning additional air sampling. Three tasks are planned: conducting ambient air monitoring at additional locations, conducting flux chamber measurements (to measure VOC emission rates at the ground surface), and evaluating the wind erosion potential of particles (62). Figure B-8 shows the location of the previous air monitoring stations and the proposed air monitoring stations.

Indoor Air

Many of the HPA buildings are leased to artists and other small business owners. Appendix D describes the PA areas by building number, historical use, current use, and possible contamination. Little indoor air sampling has been conducted at HPA. The PA area sampling plan does not include indoor air sampling (9, 10, 11).

During the PA area reconnaissance conducted in 1991, each PA building or area was visited by Navy contractors. They inferred historical chemical use from visual observations, assessed current chemical use, and assessed the evidence of actual or potential releases of chemicals to the environment (Appendix D). Navy contractors mapped, photographed, and recorded observations at each area. The focus of the survey was to document potential hazards such as sumps, pipelines, tanks, trenches, treatment equipment, and storage areas and assess evidence of chemical releases to flooring pavement, or soil. In addition, contractors observed possible asbestos-containing material in most buildings, transformers potentially containing PCBs, five additional USTs, metal based paints in many buildings, and possible past use of radioactive materials (9, 10, 11). It is possible that waste from past use of those buildings could be hazardous to the present base tenants. Tenants have occupied HPA buildings since the late 1970s when Triple A Machine Shop leased the base from the Navy.

Scrap Yard Old (IR-4) and Transformer Storage Area (IR-5)

In 1992, surface soil sampling took place at OU III. Several metals and Aroclor-1260 were detected at IR-4, the Scrap Yard, and at IR-5, the Old Transformer Storage Area. Metals and Aroclor-1260 were detected above comparison levels (Tables 7 and 8). Lead was found at the highest levels of the metals identified. Aroclor-1260 was found at five shallow areas (up to 3 feet) (21). Low levels of PAHs, VOCs, and SVOCs were also detected. The source of the metals is most likely past area activities; a wide variety of machinery, metal, and other items were taken to IR-4, disassembled, and sorted for disposal (21). Transformers were stored at IR-5 and are most likely the source of Aroclor-1260 (20). Figure B-9 shows the contaminated areas at IR-4 and IR-5.

Groundwater

Groundwater IR-6 and IR-10

Underneath the Tank Farm, IR-6, and the Battery and Electroplating Shop, IR-10, there are two groundwater contamination plumes in the shallow aquifer (Figure B-10). The plumes are from two different sources, one migrating from each of the IR areas (26). In 1992, benzene, at 72 ppb, was detected 150 feet downgradient from IR-6. Chlorinated solvents, trichloroethene (TCE), 1,2-dichloroethene (1,2-DCE), and vinyl chloride, were detected at both IR-6 and IR-10. TCE and vinyl chloride were identified in wells near the Tank Farm. TCE was the compound most consistently detected around Building 123, IR-10. Concentrations of chlorinated solvents were detected in two areas, 200 feet down gradient of Building 123 and near the Tank Farm. 1,2-DCE concentrations were below comparison values. Hexavalent chromium, molybdenum, vanadium, manganese, cobalt, cadmium, arsenic, antimony, and beryllium were above comparison values at both areas (Tables 9 and 10).

Two aquifers have been defined at IR-6 and IR-10, the shallow aquifer and the bedrock Aquifer. Groundwater sampling took place in the shallow and bedrock aquifers. Groundwater flow in the shallow aquifer is generally to the northeast, towards the bay. The bedrock aquifer in places appears to be in hydraulic connection with the shallow aquifer (26).

Food Chain

In the past, an abundance of liquid wastes including solvents and plating wastes were poured down drains at many of the HPA industrial buildings, for instance at the Battery and Electroplating Shop (16) and at the Pickling and Plating Yard (28). Those waste materials went into the combined storm drain system and out into the bay. Appendix D describes past uses and activities at PA and IR areas. At times Triple A washed sandblast grit out of the dry docks and into the bay (7).

Sampling and testing data indicate that disposal practices have contaminated soil, sediment, groundwater and surface water It is not known what effect those practices may have had on the food chain.

Environmental Sampling and Analysis Plan (ESAP) Mussel Analysis

The first portion of the ESAP was an evaluation of whether persistent and bioaccumulative hazardous substances may be entering the San Francisco Bay from HPA (see Quality Assurance and Quality Control section for data validity). To evaluate that, the Navy conducted a mussel transplantation study. Mussels were collected from an uncontaminated area in Bodega Head and transplanted in the waters surrounding HPA. Two, 30 day mussel deployments were conducted. Bioaccumulative effects testing included the following: 1) radioactivity screening; 2) inorganics and metals; 3) pesticides and PCBs; 4) SVOCs; 5) and tributyltin.

Tributyltin compounds are one of the organotins and are used in antifouling paints. Tributyltin compounds are particularly toxic to aquatic organisms (64). Background concentration of organotin compounds are frequently elevated in aquatic organisms collected near marinas and other locales where organotin-based antifouling paints are extensively used (65). Since organotin compounds are toxic to aquatic wildlife, the Navy analyzed sediments for the presence of organotins to determine if aquatic species were being impacted. The ability of microorganisms, algae, and higher organisms to reduce tributyltin and other organotins into less toxic metabolites that can be rapidly excreted seems to preclude food chain biomagnification (65). They would be of little concern to people eating fish exposed to tributyltin.

During the two deployments which took place, in 1992, bags containing 50 mussels were placed at 17 sampling stations which corresponded with each of the 17 sediment stations (Figure B-11); a listing of the mussel transplant stations and associated sites are in Table C-6. Entire mussels minus the gonads, were homogenized and tested for metals and organics. Data on controls were not provided. Cadmium was detected at 9.1 ppm at M-1 and M-2, manganese (21 ppm) and nickel (8 ppm) were also detected at mussel transplant station M-2. Similar contaminants were detected at M-3. Manganese was detected at 26 ppm at M-17. PCBs were detected in mussel tissues at M-9, at 0.65 ppm, and at M-10, 0.93 ppm. Most of the mussels deployed contained elevated levels of contaminants. ESAP mussel tissue results suggest that though Bay water samples do not contain contaminants at levels of initial concern, the levels are sufficient to cause bioaccumulation in organisms (66).

The EPA risk-based screening value (edible fish tissue, ppm wet weight) for cadmium is 11 (67). While cadmium levels detected in HPA deployed mussels were below the EPA level, cadmium levels at HPA may still be of concern if sensitive populations (e.g., pregnant women, lactating mothers, or young children) are consuming shellfish caught on or near HPA. In general population, exposure to cadmium occurs primarily by eating crops grown in contaminated soil and seafood (68). Young children may be particularly sensitive to manganese in fish (69).

The Food and Drug Administration (FDA) tolerance level for PCBs is 2 ppm and the EPA screening value for PCBs is 0.01 ppm. PCBs levels ranged from 0.17 ppm to 0.93 ppm. PCBs also may be of health concern if sensitive populations are consuming shellfish caught on or near HPA. Manganese levels were also elevated.

California has a state mussel watch program (SMW). The SMW is the State Water Resources Control Board's long-term marine water quality monitoring program. Actual field and laboratory work is done by the Department of Fish and Game. The SMW program monitors long-term trends in pollutant concentration in marine organisms, identifies locations where higher than excepted concentrations of pollutants exist, and provides the evidence needed to initiate follow-up studies and actions to detect, correct, and clean-up sources of pollution (70, 71).

For the SMW program, California mussels (Mytilus californianus) are deployed for 4 to 6 months at stations across the state and then analyzed for trace elements, pesticides, and PCBs (70, 71). There are numerous state mussel watch stations in the San Francisco Bay including a station at Hunters Point Naval Shipyard. Several areas around the bay have mussels with consistently elevated PCBs, i.e., over 0.1 ppm. During 1988 and 1989, SMW PCB values at the Hunters Point station were the highest in the bay, 272 ppb Aroclor-1254.

While the EPA screening values are preliminary indicators of human health risk and are designed to be flexible so that susceptible populations can easily be considered, the screening values EPA derives do not account for the most sensitive populations. EPA's screening value for PCBs assumes a very low consumption rate of 6.5 grams per day. This level is equal to a single 7 ounce meal per month. Subsistence fishers may consume 20 times this level (72). EPA's values assume a body weight of 70 kg. Children and some adults, particularly Asians, are considerably smaller. The screening value would need to be lowered even further to estimate a comparable level of risk for these people. EPA screening values are typically applied to fillet concentrations and do not take into account consumption practices that may be practiced by some population groups such as consumption of fish livers.

PCBs are the only substances for which FDA has issued a tolerance level in fish (73). Fish above the tolerance level are deemed to be injurious to people's health and FDA may remove it from commerce. FDA action levels provide prosecutorial guidance to FDA but do not establish a product as injurious to health. The tolerance level for PCBs is not based solely on the protection of health and levels even lower than 2 ppm may be unsafe for certain populations.

ESAP Sediment Analysis

In the second portion of the ESAP, surfical sediment analyses were evaluated. Toxicity testing on composited sediment samples was conducted on samples from 17 sediment stations (Figure B-12). Sediment sampling stations were selected to be representative of near shore sub-tidal areas of HPA. The stations were placed along the coastal perimeter of HPA from north to south, in proximity to the HPA areas of known and potential contamination Figure B-12 (30).

Surface sediments were collected as 10 separate grab samples across the sampling station surface all of which were later composited in the field (75). Subsurface sediments were collected as a single core sample from each sediment station from which a discrete sample from between 30 inches and 36 inches was collected for chemical analysis (66). The sediment toxicity sampling and analysis included the following: 1) toxicity testing of sediment samples; 2) physical testing which includes determination of grain size; 3) radioactivity testing of samples exhibiting radioactivity above background levels as determined for screening; 4) total organic carbon; 5) inorganics and metals; 6) pesticides and PCBs; 7) SVOCs; 8) VOCs; 9) and tributyltin.

During the off-shore sediment ESAP sampling that took place from April 8-16, 1992, mercury, lead, zinc, pesticides, PAHs, and Aroclor-1260 were detected (74). The higher values of metals were encountered at S-4, S-12, S-13, and S-14. A listing of the areas associated with the 17 sediment sampling stations is in Appendix C, Table C-6. Levels of mercury (5.6 ppm), lead (379 ppm), and copper (851 ppm) above comparison values were detected during the off-shore sediment sampling (74). Low levels of organotins were detected (monobutyltin at 0.01 ppm, dibutyltin at 0.250 ppm, and tributyltin at 1.10 ppm).

Intertidal sediment sampling was conducted at IR-1/21, IR-2, IR-3, and IR-7 as part of the RI (61). Ten samples were collected randomly within each of the designated areas and then composited for analysis. Several metals and low levels of VOCs, SVOCs, PCBs, and pesticides were detected at all the sampling areas. The highest lead levels were detected at IR-1/21. Contamination appears to decrease eastward with increasing distance from IR-1/21. Lead was detected as high as 42,400 ppm in IR-1/21 sediments, at 9,030 ppm at IR-2, at 99.4 ppm at IR-3, and at 1,300 ppm at IR-7. Cadmium was detected at IR-2 at 32.9 ppm; the comparison value is 0.4 ppm (Figure B-12). Antimony was detected at 4,704 ppm at IR-3. PCBS were detected at both IR-1/21 and IR-2 at 8.4 and 1.6 ppm respectively (74).

ESAP Bioassays

The third portion of the ESAP is an evaluation of HPA storm water runoff. Chronic bioassay techniques were used on appropriate species. Chronic bioassay testing is more sensitive than acute toxicity testing and addressed potential toxic side effects of exposure to HPA storm water runoff (75). In addition, contaminant concentrations in stormwater were determined by chemical analysis. Storm water toxicity testing included the following: 1) storm and bay water bioassays involving a five dilution series; 2) inorganics and metals; 3) pesticides and PCBs; 4) VOCs; 5) SVOCs; 6) and tributyltin (76).

Tables C-7, C-8, and C-9 summarize the results of the stormwater, sediment elutriate, and sediment bioassays. The storm water runoff sampling points were the same as those used for the storm water quality investigation. Many of the tests were inconclusive due to laboratory problems with controls and high oxygen demand (38).

Surface Water and Sediment

As part of the Stormwater Quality Investigation, storm drain sediment samples were collected from each of the four stations on November 17, 1990. Pre-storm drain water samples were collected from the four stations on November 16, 1990. Storm event samples were collected on December 15, 1990. A total of 44 water samples and 4 sediment samples were collected and an additional 13 for QA/QC purposes (30).

There are a total of ten drainage areas, but only four drainage areas where sampled (drainage areas A, D, H, and E) for the ESAP. Stormwater sampling station SW1 is found within drainage area D, a 35-acre area, and collects runoff from the Tank Farm and Building 901. Stormwater sampling station SW2 is found within drainage area H, a 33-acre area, which collects runoff from the Pickling and Plating Yard, the PCB Spill Area, IR-33, PA-37, and PA-44. Stormwater sampling station SW3 is found within drainage area A, which encompasses 200 acres, collects stormwater from the Bay Fill area, the Scrap Yard, the Old Transformer Storage Yard, the PCB Spill Area, the Disposal Trench, the Old Commissary, PA-41, and PA-56. Stormwater sampling station SW4, a 30-acre area, found in drainage area E collects runoff from areas PA-58, PA-28, and PA-29.

VOCs were detected at SW4 during all sampling phases. Sediment samples taken at SW4 contained vinyl chloride at 14 ppm and PCB 1260 at 24 ppm; both were above comparison values. PCB 1260 was detected at SW2 above the comparison value, but not at SW3 or SW1. Metals were detected above comparison values at SW1 and SW2 (Tables 11, 12, and 13).

During March 1992, nine stormwater/bay water samples were taken during the ESAP investigation (74). Lead at 247 ppb was the only contaminant found above a comparison value.

Food Chain Summary

The limited sediment sampling conducted to date does not provide enough information to define the extent of contamination. Until further sediment sampling has been conducted (specifically in areas were people may be subsistence fishing), ATSDR can not fully assess the sediment contamination at HPA and the potential for bioaccumulation of metals and PCBs.

The Navy's stormwater toxicity tests, bioassays and sediment analyses were inconclusive, but many of the analyses indicate that several HPA areas appear to be toxic to the test organisms exposed to different environmental media. IR-1 and IR-2 sediments had higher levels of contamination than other areas. More toxicity tests and tissue and sediment analyses would better clarify the extent of contamination at or near HPA. Fish and shellfish tissue analyses would help to indicate whether or not edible fish and shellfish are bioaccumulating contaminants.

The NOAA study of the San Francisco Bay for the area near Hunters Point, found that only a few of the biological measures of effects were elevated relative to other areas studied, which suggested that conditions were only moderately toxic (50). Some of the biological measures of effects observed off Hunters Point were low prevalences of liver and kidney lesions in white croaker and liver lesions in starry flounder off Hunters Point, very high prevalences of kidney lesions of starry flounder off Hunters Point, significantly depressed scope of growth in resident mussels for Hunters Point, sediments throughout the area are moderately toxic to amiphods in historical tests, and some background ambient water samples are toxic to sea urchin sperm cells.

B. Off-Site Contamination

During the assessment of HPA, ATSDR searched the Toxic Chemical Release Inventory (TRI) to determine if other potential chemical releases into the environment in the areas near HPA could adversely affect the people at or near HPA. The TRI is an on-line database, maintained by EPA, that contains information (self-reported by chemical manufacturers and other industries) about more than 320 different chemicals released into the environment. Data has been compiled for the period between 1987 and 1991.

A search of the TRI database was made to help determine if the contaminants of concern at HPA could be coming from other industrial sources. There were no reports of pesticide containing chemicals released into the environment within the zip code areas of the Hunters Point District or the Bayview area. There were releases of 1,1,1-trichloroethane, sodium hydroxide, sulfuric acid, aluminum oxide, hydrochloric acid, chlorine, styrene, and acetone into the air in the Hunters Point/Bayview industrial area.

C. Quality Assurance and Quality Control

In preparing the public health assessment, ATSDR relies on the information provided in the referenced documents. The Agency assumes that adequate quality assurance and quality control measures were followed with regard to chain-of-custody, laboratory procedures, and data reporting. The validity of the analysis and conclusions drawn for this public health assessment are determined by the reliability of the referenced information.

A portion of soil and groundwater samples taken at OUs I, III, and IV were invalidated due to a problem with two state of California certified laboratories (77). Holding times for 1,100 samples were exceeded. Additional samples were taken and used in the IR investigation of OUs I, III, and IV. The Navy rejected all the formaldehyde samples for the air sampling study due to problems with the cartridge media.

For the SCRS, soil samples were sent to TMA/Eberline in Albuquerque, New Mexico for radiological analysis. TMA/Eberline is accredited by the American Association for Laboratory Accreditation in the field of testing and environmental sample analysis. EPA conducted an inter-laboratory analysis for 15 HPA soil samples. NAREL conducted the gamma spectroscopy on July 13, 1992. Ra-226 was the only radionuclide detected. Samples ranged from 0.57 to 19,400 pCi/gram dry weight (79). There were discrepancies between NAREL's and Eberline's reported values for two soil samples due to a laboratory reporting error and non-heterogeneous samples matrices.

Six out of 11 of the ESAP bioassays were invalidated due to problems with controls, mortality effects from the diluents, and the use of bubbled oxygen to makeup for the lack of dissolved oxygen. As a result of high ammonia and biological demand in the offshore sediments, the addition of oxygen was required to run the bioassays (38). Test acceptability criterion for controls were not met for several of the bioassays.

D. Physical Hazards

Methane has been detected at several areas on base (Table 14). Methane represents a physical hazard because it may cause explosions and it may displace air and cause asphyxiation.

The Navy follows site safety plans, uses gas monitoring equipment (e.g., organic vapor analyzers, oxygen meters, and explosimeters) and equipment certified (e.g., non-sparking) for an explosive atmosphere when drilling in areas where the presence of methane is suspected. In 1989, as part of the solid waste air quality assessment test, the presence of landfill gases were tested for using three different methods: landfill gas migration monitoring, integrated surface sampling, and internal landfill gas sampling.

For the landfill gas migration evaluation, three monitoring probes were installed around the perimeter of HPA to evaluate the possible off-site subsurface migration of land fill gas. Locations were choosen because of the proximity of the Industrial Landfill to the site boundary. Probes were used to collect samples of subsurface gas and obtain pressure measurements at the HPA perimeter. The sample from probe PP-02 located at the northern perimeter of the Industrial Landfill, indicated the presence of methane at 56 percent. Methane was not detected in the other two samples. This may indicate migration of landfill gas. Subsurface pressure was 0.0 inches of mercury for all the landfill gas migration probes.

Five SWAQAT locations were selected for the integrated surface sampling. The integrated surface sampling technique measures gases immediately above the landfill surface and is used as an indicator of gases escaping from the landfill (78). Separate 50,000-square-foot grids were plotted at each of the five SWAQAT areas. One continuous air sample was collected 3 inches above the ground surface along a standard sampling pattern. Methane was not detected in any sample.

Internal landfill gas sampling was performed to evaluate the composition of the landfill gas within the fill areas. Thirteen landfill gas characterization wells were installed throughout the five SWAQAT areas at HPA. The wells were used to collect both subsurface gas samples and pressure measurements within the soils. Methane was detected in 7 samples at concentrations ranging from 0.5 to 83 percent (Table 14). A duplicate was taken of sample IG-7, sample IG-7D, which was lower than the initial sample possibly due to dilution of the duplicate sample with air during sample collection (24).

During an ATSDR site visit, workers drilling monitoring wells detected methane gas and ceased drilling. Methane was detected at a concentration of 46% at IR-12 (Parcel E) when a shallow vadose zone well was installed (22). The lower explosive limit for methane is 5% and the upper explosive limit is 15% (80). IR-1/21 and IR-12 are nearly contiguous to each other. The Navy believes that the methane occurs in scattered pockets (81).

According to the Navy, methane occurrence is associated with the presence of the subsurface debris. Methane is natural byproduct of the degradation of solid waste landfills containing paper, wood, household trash, and other organic debris. Figure B-13 shows some of the areas where the Navy has detected methane. Methane was not observed in areas where there are no debris, with the exception of one boring in the western part of IR-1/21 (Parcel E). Methane concentrations measured at the time methane was encountered during drilling dissipated rapidly to non-detectable concentrations, generally within minutes or hours (82).

The lateral extent of debris, and therefore potential methane pockets, is not defined on the north edge of IR-1/21 or on the north edge of IR-18 (Parcel B). At IR-1/21, the lateral extent of debris can be estimated based on the history of filling at HPA. Debris was not used for fill at IR-1/21 until 1958. The shoreline in 1948 is shown on Figure B-13; areas north of the 1948 shoreline were filled with rock material from the bedrock ridge (as opposed to debris). The 1948 shoreline is estimated to represent the maximum northern extent of possible debris areas at IR-1/21 (82).

Physical hazards in the form of shipyard debris were observed by ATSDR at the Drum Storage and Disposal Yard and outside of the Power Plant. Crumbling seawalls were also observed by ATSDR. This could present a physical hazard, from falling pieces of concrete, to future HPA occupants using areas near the seawalls.

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