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PUBLIC HEALTH ASSESSMENT

FORT ORD
MARINA, MONTEREY COUNTY, CALIFORNIA


COMMUNITY HEALTH CONCERNS AND POTENTIAL PATHWAYS OF EXPOSURE

The community health concerns evaluated in this section represent concerns expressed about potential pathways of human exposure. We got our information from proposed work plans, remedial investigation reports, sampling data, site visits, public meetings, and newspapers. ATSDR has organized the sections of this report to respond to the specific public health concerns raised by community members.

Concern - Groundwater

  • Has groundwater contamination detected at Fort Ord affected drinking water wells onpost or in nearby communities and, if so, has or will that contamination result in adverse human health effects?

Conclusions

    ATSDR has drawn several conclusions regarding the past, present, and potential future quality of the drinking water provided by groundwater near the Fort Ord area. Those conclusions are given in the discussion text that follow but the most important of those conclusions are summarized here:
  • Groundwater contamination from activities at Fort Ord has not affected the drinking water supply of Seaside, California. Seaside draws its groundwater supply from a different groundwater basin than Fort Ord.

  • There are no detections of groundwater contaminants at levels of health concern in the presently "active" drinking water wells on Fort Ord. The water at Fort Ord is safe to drink. Because the drinking water wells currently in use at Fort Ord are located far from sources of contamination, drilled to deep aquifers that are not likely to be contaminated, and monitored regularly, Fort Ord's drinking water supply should be safe to drink in the future.

  • Because the concentration of groundwater contamination detected in the past in Fort Ord and Marina drinking water wells was low and the duration of exposure was short, adverse health effects will not likely result.

  • The water supplied by drinking water wells presently used by Marina is safe to drink. Further, because Marina's drinking water wells are drilled to deep aquifers and the quality of the water is monitored regularly, Marina's drinking water should be safe to drink in the future.

Discussion

The tap water provided at Fort Ord and supplied to residences and businesses in the nearby communities comes from groundwater, which is water from wells, either private or municipal water supply wells. Fort Ord and the nearby community of Marina both draw groundwater from the Salinas Basin (HLA 1994b, p.5). Seaside located on the southwest side of Fort Ord, draws groundwater from the Seaside Basin Aquifers (see Figure 5a); (HLA, 1994b, p.5). The groundwater contamination at Fort Ord has not affected and will not affect the drinking water supply of Seaside.

Groundwater Hydrology and Groundwater Use

There are four separate groundwater-bearing zones or aquifers that characterize the Salinas Basin beneath Fort Ord (see Figure 4):

  • The Upper A-aquifer;
  • The Upper and Lower 180-Foot Aquifer;
  • The 400-Foot Aquifer; and
  • The 900-Foot Aquifer.

The Upper A-aquifer has groundwater levels ranging from 100 to 150 feet below ground surface (bgs). It is composed of fine- to medium-grained, well-sorted sands within the Pleistocene-age older dune sand (HLA, 1994b, p.32). The Upper A-aquifer is unconfined and is recharged from rainfall and surface water infiltration. The groundwater in that aquifer generally flows northwestward towards the Pacific Ocean.

Beneath the A-aquifer an extensive fine-grained relatively impermeable deposit, the Fort Ord-Salinas Valley Aquiclude (FO-SVA), that separates it from and locally confines the deeper 180-Foot Aquifer. In the Fort Ord area, the FO-SVA underlies much of the northwestern portion of the Fort but thins-out and is absent under the remainder of the Fort. The FO-SVA disappears near the Main Garrison and also along the southern Salinas basin boundary (HLA, 1994b, p. 9).

The 180-Foot Aquifer consists of 50 to 150 feet of clays, silts, sands, and gravels. The 180-Foot Aquifer is a confined aquifer where it underlies the FO-SVA but is interconnected with the A-aquifer where the FO-SVA is absent. The Upper and Lower 180-Foot Aquifers are separated from one another by a silty and clayey sand called the Intermediate 180-foot aquitard.

The 400-Foot Aquifer is a confined aquifer that generally consists of 50 to 200 feet of fine sands and silts. The water levels within the 400-Foot Aquifer vary from depths of 300 to 450 feet bgs. Much deeper, the confined 900-Foot Aquifer consists of water-bearing sands and gravels interbedded with layers of clay between depths of 750 to 1500 feet. In the Fort Ord area the 900-Foot Aquifer is isolated from sources of Fort Ord contamination. Even though the 400-Foot Aquifer is confined and probably isolated from sources of Fort Ord contamination, a few, scattered detections of contaminants have been recorded. The possible significance of those detections will be discussed in later sections of this report.

Over the years the development and use of groundwater at Fort Ord and nearby areas has lowered the groundwater level of the 180-Foot Aquifer, which resulted in irregular groundwater flow patterns and salt water intrusion toward the east from the Pacific Ocean. The Main Garrison area of Fort Ord and Marina first observed salt water intrusion in the 1960's. Marina closed all of their 180-Foot Aquifer wells by 1978 because of the declining water quality (HLA, 1994b, p. 66). 400-Foot and 900-Foot wells were then drilled by Marina. Fort Ord ceased the use of 180-Foot Aquifer wells under the Main Garrison area and drilled drinking water wells 29 and 30 to the 400-Foot Aquifer and drinking water wells 31 and 32 to 180-Foot Aquifer. Those wells, drilled in 1984, located in the East Garrison Area are isolated from and up-gradient to known sources of contamination at Fort Ord (see Figure 5b).

The Upper A-aquifer is thought to be unaffected by seawater intrusion because the aquifer is above sea level and the chloride (salt, NaCl) concentrations range from 10 to 259 mg/l (HLA, 1994b, p. 67). Seawater intrusion into the 180-Foot Aquifer beneath the Main Garrison appears to have decreased over time. The chloride concentrations for Fort Ord well 24 have decreased from 550 mg/l in 1981 to 93.5 mg/l in 1992 (HLA, 1994b, 9. 67). The confined 400-Foot Aquifer has not been affected by the seawater intrusion. Chloride concentrations in the 400-Foot Aquifer range from 16 to 243 mg/l (HLA, 1994b, p. 68).

Source of Groundwater Contamination

The Fort Ord landfills site (Operable Unit 2) is believed to be the primary source of drinking water chemical contamination on Fort Ord and nearby Marina, CA (see Figure 5a & 5b; HLA, 1994, p.24). The landfill site, consisting of 150 acres, was used for over 30 years. The northern portion of the landfill was used from 1956 to 1966. The main landfill was operated from 1960 until May 1987 when the facility was placed under interim closure (HLA, 1994, p.25; Dames & Moore, 1993, p. 7). No detailed records were kept on the amount or types of waste disposed. The landfill is believed to contain household and commercial refuse, ash from incinerated infectious wastes, dried sewage sludge, demolition materials, and in the main landfill, small amounts of chemical waste (HLA, 1994, p.25; Dames & Moore, 1993, p. 7). The wastes were placed in trenches 30 feet wide, 10 to 12 feet below ground surface, and 10 to 15 feet apart. The wastes in the trenches were placed 10 feet above the trench bottom and covered with two feet of native dune sand deposits excavated during trenching operations (Dames & Moore, 1993, p. 4).

Contaminants from the landfill infiltrated into the Upper A-aquifer and have migrated in a west-northwesterly direction toward the Fort Ord boundary (see Figure 5a & 5b). Contaminants that migrated to the western limits of the FO-SVA may have intermixed with the waters of the Upper 180-Foot Aquifer at that point and may have resulted in local contamination of that aquifer.

Drinking water well quality.

Fort Ord - Current and future drinking water quality.

There are no detections of contaminants above MCLs in the presently "active" drinking water wells on Fort Ord. Presently, only Fort Ord wells 29, 30, and 31 are active water wells (see Figure 5b; POM, 1995a). Well 32 was closed in 1996 and will be replaced by a to-be-constructed well 33. Those wells were drilled either into the Lower 180-Foot Aquifer which is partially confined and hydrologically isolated from contamination in the A-aquifer or drilled into the confined 400-Foot Aquifer. The currently used wells are upgradient from the Fort Ord landfill or any other source of groundwater contamination in the Main Garrison Area of Fort Ord. Therefore, the currently active Fort Ord wells will not be affected by contaminants from that source in the future.

The quality of the water produced by the active Fort Ord drinking water wells is regularly monitored thereby further assuring the future safety of that water.

Marina Coast Water District - Current and future drinking water quality.

Contaminants have not been detected in the active Marina Coast Water District wells 10 and 11, both in the 900-Foot Aquifer (see Figure 5b). Water from Marina wells 10 and 11 is safe to drink.

Future contamination from Fort Ord of those wells is unlikely because groundwater contamination from Fort Ord sources does not affect the 900-Foot Aquifer. The quality of the Marina Coast Water District wells is also monitored on a regular basis to ensure its future safety.

Past Drinking Water Contamination

The drinking water well sampling data taken between 1985 to 1993 from Fort Ord's and 1985 to 1994 from Marina's drinking water wells were reviewed by ATSDR to evaluate if contaminants in those wells may have posed a potential health risk to persons drinking and using the water.

To determine which Fort Ord-related contaminants are potentially of public health concern, ATSDR reviewed the analytic data complied during the interval from 1985-1994. The data reviewed was a record of all detections above the Certified Reporting Limit (CRL). Tables 5 and 6 in this section list those contaminants and concentrations of those contaminants measured in the samples obtained from Fort Ord and Marina drinking water wells. The duration of detections, which is the time interval contaminants were detected in all the drinking water wells in use during the 1985-1994 period, is also given in these tables.

ATSDR evaluated those contaminants to determine whether exposure to them had public health significance. Factors considered in the identification of the contaminants to be further evaluated include:

  • Concentrations of contaminants;
  • Duration and frequency of exposure;
  • Field data quality, laboratory data quality, and sample design.

The listing of a contaminant in Tables 5 and 6 does not mean that adverse health effects will result from exposure to that contaminant. The human health implications of exposure to those contaminants is discussed in the subsequent sections of this report.

The data tables include the following abbreviations:
LTHA = Lifetime Health Advisory for drinking water (70-years)
MCL = Maximum Contaminant Level for drinking water; Lifetime exposure.
ppb = parts per billion (ug/L = micrograms per liter)

The following paragraphs detail the detection of contaminants in individual drinking water wells. We evaluated the human exposure to contaminants as if people were exposed to the maximum levels of the contaminants detected. However, in most cases water is drawn from more than one well at a time, blended with the water from other wells, treated, and pumped to storage tanks and to the water distribution system as finished water. Thus, the contaminant level(s) of the blended, finished, tap water supplied to a residence or other point of use is usually much less than measured in an individual water supply well.

Figure 7 is a schematic profile of the Fort Ord water system. Drinking water from the active wells is first pumped into equalization and/or sand tanks. Then the water is treated and pumped to reservoir tanks. This entire process provides multiple opportunities for "off-gassing" of volatile chemicals (eg TCE, etc.) which further reduces the level of contamination. Finally, the finished water is pumped into the distribution system. All standby wells must be sampled and approved by the California Department of Health Services (CDHS) before they can be used as an emergency water source. No standby wells have been used for drinking water since the mid-1980's (POM, 1996b).

Fort Ord - Past drinking water quality.

Various combinations of traces of carbon tetrachloride, chloroform, tetrachloroethylene (PCE), trichloroethylene (TCE), and xylenes were detected in wells 14, 18, 19, 21, 23, 24, 26, 27, and 28 from May 21, 1985 to March 16, 1993 (see Table 5). Examination of the data and geologic cross-sections given by HLA (1994b, Plates 2 and 5) confirmed that wells 19 and 24 were developed in the 180-Foot Aquifer, while wells 27 and 28 were drilled to the depth of the 400-Foot Aquifer. Those wells lie in the general path of contamination migration in the Upper A-Aquifer from the Fort Ord landfill. The wells in the 180-Foot Aquifer may have been affected by contaminants migrating beyond the limits of the FO-SVA and merging with the groundwater of the Upper 180-Foot Aquifer or by cross-contamination of the aquifers by poorly constructed or damaged wells. Well 27, even though drilled to the 400-Foot Aquifer, was screened at several levels in the Upper and Lower 180-Foot aquifer as well as the 400-Foot Aquifer and thus, contaminant detections in this well were probably due to causes similar to wells 19 and 24. Well 28 was only screened at greater depths and may have been producing water from the base of the 180-Foot Aquifer or from the top of the 400-Foot Aquifer. The source of limited detection of contaminants in this well was not clear but may be due to cross-contamination through a damaged or poorly constructed well bore.

The locations of Fort Ord and Marina, CA water supply wells used in the past or present, the location of the principle source of groundwater contamination, and the Fort Ord landfills are given in Figure 5b. Table 7 gives the date those wells were drilled, closed (eg high chloride content, mechanical problems, etc.), and/or destroyed (plugged and abandoned).

The history of contamination of individual Fort Ord drinking water wells is given below, as well as ATSDR's conclusion about the potential health risk associated with the consumption of water from those wells. Tables 8 and 9 display the potential cancer and non-cancer risk that might be associated with consumption of water from these wells under "worst-case" assumptions. Please review the footnotes given with Tables 8 and 9 for definition of the "worst- or maximum-case" risk.

The calculated potential cancer risk "maximum" and "possible" given in Table 8 are at levels of 1.00E-5 or less; this cancer risk is not of public health concern. Similarly the calculated child and adult doses documented in Table 9 are less than Reference Dose levels and do not represent a possible increased human health risk due to non-cancerous causes.

Well 14 had a total of seven trichloroethylene detections from May 14, 1985 to August 2, 1985. Five detections were above the 5.0 ppb MCL, with a maximum value of 14.0 ppb. As of 1975, Well 14 was used as backup well until it was destroyed in 1989. The TCE contamination in well 14 was not present at concentrations high enough or for a time interval long enough to pose a threat to human health.

Well 18 had five detections of trichloroethylene from May 21, 1985 to August 2, 1985, all of which were above the 5 ppb MCL. The maximum trichloroethylene detection was 25.0 ppb. Trichlorofluoromethane was detected once, below the 2000 ppb LTHA, on May 21, 1985. Well 18 became a backup well in 1975 due to its high chloride levels, until its destruction in 1989. The contaminants in well 18 were not present for a duration which could pose a threat to human health.

Trichloroethylene (TCE) was found at concentrations slightly above the 5 ppb MCL in Fort Ord Well 19 (see Figure 5b). Based on the data available to ATSDR 21 samples were taken from July 31, 1985 to April 5, 1988. Of these samples only two were slightly above the 5.0 ppb MCL, 5.3 and 5.4 ppb. Tetrachloroethylene was also detected six times from July 31, 1985 to August 2, 1985, but none of those detections were above the 5 ppb MCL. Well 19 was drilled in 1952. As of July 1986 well 19 was active, but the use of the well was subsequently discontinued due to increased chloride ion concentration due to seawater intrusion (POM, 1995a). No adverse effects are expected from those contaminants in well 19 because the MCLs are based on a lifetime exposure (70-years) and the exposure was not for a lifetime.

Tetrachloroethylene was detected five times in Well 21, all below the 5 ppb MCL. Trichloroethylene was detected five times from August 6, 1985 to August 8, 1985, all detections were below the 5 ppb MCL. The contaminants in well 21 were not at levels which could cause adverse human health effects.

Well 23 had six detections of trichloroethylene from July 31, 1985 to August 2, 1985, all of which were above the 5 ppb MCL. The maximum detection value was 8.9 ppb. Well 23 was placed on standby status in 1975 due to high chloride levels. The levels of contaminants detected were not at a duration which could pose a threat to human health.

Well 24 only had one detection, 2.5 ug/L of TCE on March 16, 1993. Since that contaminant was detected once and it was not above the MCL, 5 ppb, it did not pose a threat to human health.

Well 26 had four carbon tetrachloride detections from August 6, 1985 to August 7, 1985, all of which were below the 5.0 ppb MCL. The maximum detection value was 0.54 ppb. Well 26 did not pose a threat to human health due to the low contaminant levels.

ATSDR reviewed a memorandum to the Environmental Chief, Jim Willison, from Dann Stein-Freer dated April 19, 1991. That memo noted that concentration levels of 47 ppb tetrachloroethylene and 30 ppb naphthalene had been detected in Fort Ord Well 27. ATSDR has been unable to verify these contaminant concentrations from the available data. The available data indicates that, even if these reported values are accurate, those levels were not sustained over any length of time. For this reason ATSDR did not assign a potential health risk to these unverifiable observations. Carbon tetrachloride was detected four times from July 31, 1985 to August 7, 1985, with all of the values below the 5 ppb MCL(1) established by the U.S. EPA. Well 27 was placed in inactive status in July 1986.

Twenty-four samples were taken from Fort Ord Well 28 between May 21, 1985 to August 31, 1990 (see Figure 5b). Of those samples, six were above the 5 ppb MCL for carbon tetrachloride1. Those samples were collected on May 21, 1985, September 9, 1986, September 9, 1986, September 22, 1988, July 12, 1989, and July 17, 1989. The levels detected were 6.0, 9.0, 9.1, 9.8, 6.1, and 8.0 ppb, respectively. On September 22, 1988 a water sample from Well 28 was collected which indicated 9.8 ppb carbon tetrachloride, but upon resampling the well the carbon tetrachloride level was found to be 1.1 ppb.

Tetrachloroethylene was detected in sampling conducted on April 5, 1988, 48.0 and 53.0 ppb. These detections exceed the 5 ppb MCL, but are not considered a threat to human health because of their short duration.

Well 28 was drilled in 1968 (POM, 1995a). Based upon the data available to ATSDR, well 28 was closed in 1988 (correspondence Clifford Bowen 1988). During the 20 years Well 28 was used, there were only five or possibly six times that the level of carbon tetrachloride exceeded the 5 ppb MCL which was established by EPA to evaluate a safe lifetime (70-year) exposure level. Human exposures to carbon tetrachloride of such short duration and at the low levels detected in Fort Ord Well 28 are unlikely to result in any adverse health effects.

Please refer to Tables 8 and 9 for a summary of the potential cancer and non-cancer risks, respectively, from the drinking water in wells 14, 18, 19, 23, 24, 26, 27, and 28. These values are based on the maximum possible exposure.

In summary, all of the contaminant levels recorded were low and human exposures to those contaminants was of short duration. Contaminants detections above the MCLs were only recorded during a 6-year interval, and then, not in all the wells at the same time. Adverse health effects from those exposures is unlikely.

Marina Coast Water District, California - Past drinking water quality

Well 8A, now closed, produced water from both the 180- and 400-Foot Aquifers, contained traces of carbon tetrachloride below the 5 ppb MCL from January 9, 1991 to April 3, 1991 (see Figure 5b).

All detections of contaminants in Marina Well 9, a backup water well in the 400-Foot Aquifer, were below the MCLs. However, in the interval from August 19, 1985 to July 6, 1994 bromodichloromethane, bromoform, bromomethane, carbon tetrachloride, chloroform, cis-1,2 dichloroethylene, dibromochloromethane, trans-1,2 dichloroethylene, 1,1,1- trichloroethane (1,1,1-TCA), tetrachloroethylene (PCE), and trichloroethylene (TCE) were all detected below the MCLs in Marina Well 9 (see Table 6). However, the levels were low. Because the contaminant detections were of short duration and at low levels in backup Well 9, no adverse health effects are likely from use of this well.

In 1991, a few low level detections of bromodichloromethane, bromoform, chloroform, dibromochloromethane, m-p-xylene, and toluene were noted in Marina drinking water Well 12, also drilled into the 900-Foot Aquifer. Since those original contaminant detections, there have not been any reoccurrences (see Table 6). Well 12, drilled in northern Marina about 1200 feet northwest of the Fort Ord - Fritzsche Army Airfield boundary to a total depth of about 2020 feet, is far removed geographically and geologically from the sources of Upper A-aquifer contamination at Fort Ord. The source(s) of contamination recorded in Well 12 may range from sampling errors, to laboratory contamination of samples, to unknown sources of contamination. However, because the contaminant detections were of such short duration and at low levels in Well 12, no adverse health effects are likely to result from the past use of this well. Regular monitoring of the quality of drinking water produced from the Marina wells ensures that present or future use of water from Well 12 or other wells currently used will be safe.

Private wells.

There are no private wells in Seaside or off-post near the landfill or Fritzsche Airfield (MCHD, 1995). A small number of private wells are located throughout Marina. These wells were drilled to depths between 80-120 feet and are used for irrigation only. These private wells showed traces of nitrates (MCWD, 1995). Nitrates commonly originate from sources such as fertilizers or onsite sewage disposal systems. These private wells do not pose a human health risk for the residents if they are used only for irrigation.

Concern - UXO/OE

  • Is the general public's health and safety at risk from unexploded ordnance (UXO) and ordnance and explosives (OE) when they visit Fort Ord or make use of the areas and facilities being made available or developed for public use following base closure?

Conclusion

    ATSDR reviewed the procedures used to inventory and locate UXO/OE sites and the process and procedures that have been or are being used to cleanup those areas. Those methods and actions are protective of public health and safety. People who trespass into areas of known or suspected UXO/OE may put themselves at risk.

Discussion

Areas of Fort Ord, particularly the Impact Area, were used as field target ranges, maneuver areas, and training and staging areas for infantrymen and light infantrymen. As a result of these activities a number of Ordnance and Explosives (OE) and Unexploded Ordnance (UXO) have been found on the site. OE consists of remains from the following materials: bombs and warheads; guided and unguided ballistic missiles; artillery, mortar, and rocket ammunition; small arms ammunition; antipersonnel and antitank mines; demolition charges; pyrotechnics; grenades; torpedoes and depth charges; containerized or uncontainerized high explosives and propellants; and all similar or related items designed to cause damage to personnel or material. UXO is a subset of OE consisting of unexploded bombs, warheads, artillery shells, mortar rounds, and chemical weapons (Archives Search Report, 1993, p.6-1).

Suspected ordnance contamination sites were identified through the archives search report (see Figure 6; Archives Search Report, 1993). Those 22 sites were then sampled for OE and UXO beginning on January 6, 1994 (Ft. Ord Final Report, 1994). In the areas zoned for reuse in the BRAC Reuse Plan (Base Reuse Plan, 1994) and those with confirmed contamination, the UXO will be excavated and removed for disposal.

We evaluated 6 of the sites because they are of the greatest community concern and may pose a threat to human safety if not cleared of UXO/OE. Sites 12, 14, 15, 16, 18, and 19 have been identified for clearing the UXO (see Figure 6; Archives Search Report, 1993). Site 22, an OE site is of local community concern.

The UXO sites have been or will be investigated through visual and geophysical surveys. The visual survey involves a visual scan and a sweep of the surface using metal detectors. The geophysical survey entails using magnetometers to explore the surface and subsurface terrain of the site. Any ferrous (iron) detections are marked and recorded for future excavation and follow-up (UXB International, 1994, p. 5). Some of the sites not discussed in detail below, will or are receiving a random surface and/or subsurface investigation to determine the potential for OE to exist within the site (Archives Search Report, 1993). The reader is directed to Figure 6 for the location of the sites discussed below.

Site 12 has undergone a sampling investigation and an ordnance time critical removal action was not recommended (see Figure 8; POM, 1996c).

Site 14 is being investigated and only a portion of the site is recommended for an ordnance time critical removal action (POM, 1996c). Sites 15 and 16 may require burning-off terrain -in order to locate the ordnance and to maintain the local ecologic setting. Sites 15 and 18 may require subsurface excavation. Those sites are expected to have a large volume of UXO confined to a small area. Site 14 was used for subcaliber artillery and mortar practice; site 15 for multi-range/impact area; and site 18 for minefield and air bombing practice (Archives Search Report, 1993). Sites 14, 15, and 16 have been designated for wildlife habitat under the Natural Resource Management Area (Base Reuse Plan, 1994). Sites 15 and 16 require further investigation prior to determining the action required. Parts of site 18 will be used for the California State University Monterey Bay campus (Base Reuse Plan, 1994). Because site 18 will be used for the university in the near future, it has first priority for clearance (Ft. Ord Final Report, 1994, p.I-3). Site 18 and a large surrounding area has undergone an ordnance time critical removal action to a depth of 4 feet (see Figure 8; POM, 1996c). Site 18 was renamed to Site CSU, which includes sites 4c, 7, 8, 18, and the north portion of site 13b (POM, 1996c). In October 1996, the Army will produce a final draft EE/CA and an Action Memorandum which proposes and documents the action to be taken for OE sites.

We also looked at the Beach Ranges (UXO-Site 22) because the community is concerned about the safety of these ranges because they are accessible from the Pacific Ocean beaches on the west. There is no fencing on the Pacific Ocean side of the Beach Ranges. A portion of site 22 has a surface litter and surface soil contamination of small arms OE. Sharp shards of bullet casings and the lead cores of bullets are easily observed in the target areas of these firing ranges. Until cleanup measures are complete in the areas of high concentration of bullet surface-soil coverage, these sharp bullet fragments pose a physical hazard to trespassers that may walk through or recreate in these areas. The proposed future recreational uses of this area provide for access restrictions, such as boardwalks and railed trails, to areas of hazard (see the following concern on lead in the beach ranges). Site 22 has undergone a sampling investigation and an ordnance time critical removal action was not recommended (POM, 1996c).

Concern - CAIS

    > In addition, do the Chemical Agent Identification Sets (CAIS) reportedly used and buried at Fort Ord represent a potential threat to human health?

Conclusion

    There is no evidence of the disposal of CAIS kits at Fort Ord. However, if CAIS kits are found on site in the future, they would contain such a small quantity of dilute agent that any adverse human health effects are unlikely.

Discussion

Records show that Fort Ord used CAIS prior to 1974 for troop field training near the Imjin Road landfill area, off 10th Street Gate Road. In 1974, four CAIS in the inventory were removed from the installation (Survey and Analysis Report, 1995, p.CA-1). The specific type of kits is unknown. There is no information to confirm that CAIS kits were disposed of or buried at Fort Ord, but there is public concern that CAIS kits may be accidentally discovered there.

CAIS usually contain blister and nerve agents. If CAIS was discarded at Fort Ord, the specific type of kits is unknown. These kits can contain test tube-sized vials of diluted chemical agents. The blister agents can include Levinstein Mustard, Distilled Mustard, a mixture of mustard agents, and Lewisite. The nerve agents may contain Tabun, Sarin, Soman, and O-ethyl-S-(2-disopropylaminoethyl)methyl phosphonothioate (Toxic Chemical Agent Safety Standards, 1995, p.11-12).

There is local public concern that remedial activities such as construction or excavation may uncover and damage these kits, causing a release. A search of Fort Ord records and site investigations have not discovered any information or evidence that would help to locate any CAIS kits that possibly may have been disposed at Fort Ord. If CAIS kits are discovered it is likely they will be found by accident. However, if the kits are still intact, they would contain a very small quantity of dilute agent. If remediation or construction workers were exposed to an accidental release of CAIS kit contents in an area of limited ventilation, some short-term adverse health effects might result. However, the health of the community would not be affected by the accidental excavation of these kits.

If kits are found, federal law requires that any activity involving the removal, transport or disposal of chemical agents be coordinated with the U.S. Army Chemical Demilitarization Program (USACDP) and the National Center for Environmental Health (NCEH) of the Centers for Disease Control and Prevention (CDC). These two organizations develop safety procedures for chemical agent removal. Safety programs include plans for; excavation that minimize the possibility of an accident, monitoring during activities to detect any leaks that occur, limiting the spread of any contaminants that might leak, and emergency response and emergency medical procedures, if needed.

Concern - Stormwater Outfalls

  • Does the surface water discharged from the beach stormwater outfalls contain contaminants which could threaten human health?

Conclusion

    The surface water from the beach stormwater outfalls has low levels of contaminants and infrequent discharges which do not pose a threat to human health.

Discussion

There are four ocean surf zone outfalls: OF-01 through OF-04, one beach outfall: OF-30, and two dune outfalls: OF-05 and OF-15 (HLA, 1995; for exact locations see Plate 5). Construction of the storm drain system began in the 1940's. OF-01 was operational by 1949, OF-02 and OF-03 originally discharged into the dune face in 1956 and then continued to the ocean surf zone by 1966. OF-04 discharged into the dune face by 1966 and then, by 1978, discharged into the ocean surf zone (HLA, 1995). Beginning in the 1960's, storm water was treated before discharge. In the 1970's, National Pollutant Discharge Elimination System (NPDES) permits were obtained which allowed storm water to be discharged without treatment. By 1990 all of the stormwater outfalls were connected to the sanitary sewer system (HLA, 1995).

Records of stormwater releases were maintained beginning in 1979. These records show that there was one release in 1979, one in 1983, one in 1986, two in 1989, 38 in 1990, and 45 in 1991 (HLA, 1994g). The quantity discharged ranged from 30 to 125,000 gallons per event.

Stormwater samples were taken from the outfalls after two storms on January 23, 1994 and March 24, 1994. These samples did not contain any contaminants above the MCLs (HLA, 1994c). Based upon our review of the available data and information, the stormwater outfalls do not pose a threat to human health because of the low levels of contaminants and the short duration of possible accidental exposure.

Concern - Offshore UXO

  • Do the UXO in Monterey Bay pose a physical hazard to human health?

Conclusion

    Information on the specific location and type of UXO that may exist in Monterey Bay is not available. It is probable, however, that the UXO in the Bay lies at water depths accessible only to well trained technical divers. Because of the lack of information it is not possible to further evaluate the potential physical hazard represented by the UXO in Monterey Bay.

Discussion

The documents reviewed by ATSDR suggest that large caliber ordnance may have been fired into Monterey Bay during World War II training (HLA, 1995, p. 23 & 25). Those documents also suggest that small arms fire could have entered the Bay from the Fort Ord Beach Ranges until 1991, when those were closed (HLA, 1995).

A Restricted Zone was established in Monterey Bay to prevent ships from sailing into the path of fired munitions. Prior to 1952 the Restricted Zone was a wedged-shaped arc which extended 8 miles off the Fort Ord Beach-front area. That zone was later revised to a rectangular area extending 4.5 miles off the Fort Ord southern and northern boundary lines (HLA, 1995, p. 3 and Plate 2). The depth of the water in the Restricted Zone ranges from 168 to 1,890 feet (HLA, 1995).

There is no detailed inventory of the specific location and type of UXO that may exist in Monterey Bay. The US Navy has removed UXO from Monterey Bay when it has been located. However, the depth of the water in the Restricted Zone ranges from 168 to 1,890 feet (HLA, 1995). Scuba diving to depths of 168 feet or greater requires serious technical diving skills and thus, it is probable that most UXO in Monterey Bay lies below depths commonly visited by recreational divers.

Concern - Lead in the Beach Ranges

  • Is the lead concentration in the Beach Ranges (RI-Site 3) at levels which could cause adverse human health affects?

Conclusion

    Based upon the available data, the beach ranges, after clean-up of the zones of "heavy" bullet surface-soil concentration, will not contain lead levels which could pose a threat to human health.

Discussion

Lead sampling was performed in three distinct geographic areas broken down by three bullet surface-soil coverage concentration levels. The three geographic areas are: Study Area 1 - Ranges 11 and 12, Study Area 2 - Ranges 5 through 8, and Control Area - area between Ranges 8 and 9. The bullet surface-soil coverage concentration levels are: heavy (> 10 percent ammunition cover), moderate (1 to 10 percent ammunition cover), and light (< 1 percent ammunition cover). The "heavy" zones comprise four percent of the Study Areas, the "moderate" zones compose five percent of the Study Areas, and the "light" zones compose 91 percent of the Study Areas (HLA, 1994f). Please see HLA (1994d; Plate 8) for a detailed map of the Study Areas.

A maximum background level of 51.8 ppm for lead in soil was used for comparison (HLA, 1994e). The soil samples were collected from November 30, 1993 to December 9, 1993. The maximum detection of lead in the "light" areas was 43.20 ppm (HLA, 1994d). This value is below the background level and therefore the light zones do not pose a threat to human health.

The "moderate" areas had three elevated detections of 32,600; 3,840; and 2,470 ppm (HLA, 1994d). If these "outlying" samples are removed from consideration, the average detection value was 256.29 ppm. This value is below the 500 ppm EPA Action Level for residential soil clean-up. Since the beach ranges are to be used solely for recreational use, the EPA Action Level is a very conservative value. Assuming that a child visits the beach once a month, ATSDR determined that a lead level of 4,300 ppm would be safe. It is also assumed that a child would not ingest more than 0.1 g of sand per visit because sand is not palatable. Boardwalks and/or railed trails will be constructed to restrict use of the dunes (BRP, 1994). Based upon the available data and the proposed access restrictions, the "moderate" areas are determined to be no threat to human health.

The "heavy" zones had a maximum detection of 46,300 ppm (HLA, 1994d). All of the "heavy" areas are in the "clean-up process" to levels below 1,860 ppm (POM, 1996b). The U.S. EPA Integrated Uptake BioKinetic Model determined that children's blood-lead levels would not exceed 10 micrograms per deciliter (ug/dL) at lead levels of 1,860 ppm (POM, 1995b; POM, 1996d). The EPA's threshold blood-lead level of concern is a level greater then 10 ug/dL. A pilot study on 1,000 cubic yards removed lead through visual and mechanical methods to an average level of 5.6 ppm. This level of 5.6 ppm is similar to the anticipated lead levels after excavation of the "heavy" areas (POM, 1996c). Most of the lead was detected in the upper 2 feet of the dune sand. It is also assumed that humans will not be exposed to sand greater than 2 feet deep (HLA, 1994f). The proposed clean-up will remove the upper two feet of the "heavy" zone dune sands. Removal of these lead-contaminated sands, coupled with the proposed recreational use restrictions, such as boardwalks and railed trails, eliminates the potential health risk of those areas.

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