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PUBLIC HEALTH ASSESSMENT

SAVANNA ARMY DEPOT ACTIVITY
SAVANNA, ILLINOIS


EVALUATION OF ENVIRONMENTAL CONTAMINATION AND
POTENTIAL EXPOSURE PATHWAYS

Introduction

In this section, ATSDR evaluates environmental data to determine whether contamination poses hazards to people having access to or living near the SVADA site. ATSDR's health assessments are driven by exposure to (contact with) contaminated media. In evaluating exposure pathways, ATSDR determines whether exposure to contaminated media has occurred, is occurring, or will occur through ingestion, dermal (skin) contact, or inhalation of contaminants. When exposure to contaminated media occurs, the exposure pathway is regarded as "complete." To determine whether completed pathways pose a potential health hazard, ATSDR compares contaminant concentrations to health-based comparison values (CVs). CVs are calculated by ATSDR toxicologists, using available scientific literature on exposure and health effects. These values, which are derived for each of the different media, reflect the estimated contaminant concentration for a given chemical that is not likely to cause health effects, given a standard body weight and a standard daily ingestion rate for a specified period. Contaminants detected above the CVs do not automatically present a public health hazard. If contaminant concentrations are above CVs, ATSDR further analyzes exposure and the toxicology of the contaminant to determine whether a public health hazard could occur.

ATSDR reviewed available data from environmental monitoring at SVADA. Many known or suspected areas of contamination on the installation have not yet been fully evaluated. This public health assessment will only evaluate the sites for which sampling data are available. Tables 1 and 2 present ATSDR's site-by-site evaluation of IRP sites. ATSDR identified and evaluated the following possible exposure pathways at SVADA: groundwater, soil, surface water and sediment, biota (livestock, game, and fish), UXO, and radiation. The following sections present an evaluation of potential exposure pathways, which are also summarized in Table 3.


Groundwater

Conclusions

No one has drunk or is drinking contaminated groundwater; therefore, ATSDR considers that contaminated groundwater at SVADA is not a past or present public health hazard. Although it is unlikely that contamination will migrate horizontally or vertically to the extent necessary to contaminate existing water-supply wells, monitoring of plumes and in-use water-supply wells at the installation is recommended to ensure the safety of on-site and off-site drinking water supplies until all necessary remediation is completed. In addition, further characterization of possible groundwater contamination is necessary at some sites evaluated in this PHA, specifically Sites 16, 17, 20, 50, and 75. ATSDR assumes that construction of new water-supply wells will not take place until assessment and remediation of groundwater is complete and that, until remediation is complete, the above recommendation regarding monitoring will be implemented. Given these assumptions, ATSDR considers future consumption of groundwater to pose no apparent public health hazard. If either of these assumptions proves false, ATSDR will reconsider its evaluation. ATSDR will review remediation and reuse plans when they are finalized, as well as additional data as they become available.

Discussion

Groundwater Use

    On-Site

    Table 4 lists all of the water supply wells at SVADA. The main installation water system draws from three deep (1,114 to 1,200 feet) wells at Buildings 107, 260, and 701, which are arranged in a looped system to supply the installation's administration area. A fourth deep well at Building 645 is connected to the main system, but has been out of service for approximately 15 years (Dames and Moore, 1994c; SAIC 1997b). Water from these wells is treated by chlorination, fluoridation, and polyphosphate at the well head (SAIC, 1997b) and is tested regularly for potable water parameters such as fecal coliform, lead, and fluoride (Clarke, 1999a). Three other wells, which are considered "transient," serve facilities in the central and northern portions of the installation. They are at Building 2112 (the Open Burning Ground Change House), Building 2205 (The TNT Washout Facility), and Building 2213 (the Stonehouse), and are 280 feet deep, 1,078 feet deep, and 20 feet deep respectively. They are shot-chlorinated and tested for bacteria once a year. Three additional wells are not treated with chlorine and supply nonpotable water; two of these wells are out of service and one is used for watering cattle. Four shallow "sandpoint" wells, pumped by windmills, are also used to provide water for cattle (Dames and Moore, 1994c; SAIC, 1997b).

    Off-Site

    An off-site well survey was conducted as part of the 1994 RI using state well records and U.S. Geological Survey (USGS) maps. About 150 possible wells were identified within approximately 1 mile of the SVADA boundary. State well records indicated that most of the off-site water supply wells draw groundwater from the Galena aquifer and are private wells used by households. Some wells are screened in the overburden gravel of the Henry formation and are primarily used for irrigation and watering livestock. The Hanover Township, Illinois, water supply well is about 2.4 miles east of SVADA (in Jo Daviess County). It is screened from 500 to 1,090 feet bgs, drawing primarily from the Cambrian-Ordovician aquifer. The town of Bellevue, Iowa, has two municipal wells that draw groundwater from the deep Cambrian sandstone aquifer (Dames and Moore, 1994c).

Nature and Extent of Groundwater Contamination

    On-Site

    A few groundwater plumes have been identified at SVADA. They are all relatively shallow and localized near the sites where the contamination originated.

    Two plumes of explosives-related groundwater contamination are associated with the CF Melt and Pour Facility Leaching Field and Sump (Sites 24 and 25). One plume originates from the leach pit area and one from the leach field. The leach field plume extends roughly 1,000 feet downgradient and is estimated to extend to a depth of roughly 75 feet bgs. The leach pit plume has a similar horizontal extent, but is shallower. In both plumes, the explosives 1,3,5-TNB and 2,6-DNT were the only contaminants considered to be site-related. 1,3,5-TNB was detected above its CV in both plumes, at a maximum of 400 micrograms per liter (µg/L) in the leach field plume. 2,6-DNT was detected below its CV in both plumes. There are no shallow water supply wells in the immediate area, but there is potential for the contamination to migrate to the Mississippi River. In addition, there is a deep bedrock water supply well at Building 701, about 1,200 feet north of the leach pit. This well was not sampled as part of the investigation of the CF and CL Areas (Dames and Moore, 1994b).

    Groundwater contamination has been found at the Open Burning Ground (Sites 13 and 14). During 1992-1993 sampling, the following compounds were detected above CVs, at the stated maxima (in µg/L): 1,3,5-TNB (6,200), 2,4,6-TNT (4,800), barium (41,000), beryllium (1.82), cadmium (369), copper (7,200), lead (13,000), manganese (12,000), and zinc (16,000). The lowest depth at which explosives were found was 22 ft bgs. No explosives were found in the Open Burning Ground water supply well (Dames and Moore, 1994a). Groundwater contamination at the Open Burning Ground has the potential to migrate to the Mississippi River.

    A shallow plume of explosives-related compounds is associated with the former TNT Washout Facility Lagoons (Sites 21 and 22); the plume is downgradient of the lagoons, moving toward the Mississippi River. Soil in the lagoons has been remediated, but only a pilot study of groundwater remediation has been completed to date. Sampling during the 1994 RI found the following contaminants above CVs, at the stated maxima (in µg/L), in this plume: 1,3,5-TNB (870), 2,4,6-TNT (830), 2,4-DNT (79), and RDX (5). The deepest occurrence of explosives is 78 feet bgs. In addition, six metals (manganese, thallium, barium, calcium, potassium, and zinc) and two anions (nitrite and sulfate) were found to be elevated above background concentrations. However, the RI suggested that background levels and natural sources of these substances be further characterized before classifying them as site-related. The deep-bedrock supply well at the TNT Washout Facility was sampled during several rounds of investigations; no explosives were detected (Dames and Moore, 1994c).

    Groundwater sampling at the Fire Training Area (Site 67) found contamination by organic compounds including TCE, 1,2-dichloroethene (DCE), and total petroleum hydrocarbons (TPH). Soil at the Fire Training Area has been remediated. Groundwater contamination is being addressed within the Lower Post groundwater management program, which is dealing with Lower Post groundwater as one unit (Clarke, 1999c). High levels of contamination include a layer of free product (waste oil contaminated with solvents) floating on top of the water table downgradient of the former location of a waste oil tank. Maximum observed concentrations (in µg/L) of the primary contaminants were: TCE (210,000) (above CV); 1,2-DCE (20,000) (above CV); and TPH (480,000) (no CV). The groundwater plume extends about 250 feet downgradient of the edge of the site (Dames and Moore, 1993).

    Trichloroethene (TCE) at a maximum of 20 µg/L (above CV), as well as other volatile organic compounds (VOCs) at low levels, were detected in groundwater at Site 20, the Abandoned Landfill (Dames and Moore, 1990). VOCs were detected at low levels in groundwater at Site 75 (SAIC, 1997b). Further investigation is necessary at these sites. In addition, as noted in Table 1, groundwater sampling has been incomplete or nonexistent at some of the other sites considered in this PHA, specifically Sites 16, 17, and 50.

    Off-Site

    Sampling data available at the time this public health assessment was prepared indicated that groundwater contamination had not migrated off site, except for some possible discharge to surface water. Because shallow groundwater at SVADA generally flows toward the Mississippi and Apple Rivers (Dames and Moore, 1994c), it is unlikely that groundwater contamination would migrate to off-site wells. However, groundwater flow is reversed when water levels in the Mississippi River are high (Dames and Moore, 1994c). In addition, groundwater in the bedrock aquifer may migrate unpredictably via voids and fractures in the bedrock (Dames and Moore, 1991). Therefore, ATSDR recommends ongoing monitoring of plumes.

Evaluation of Potential Public Health Hazards

    Past and Current Exposures

    In general, shallow water-supply wells at SVADA (including cattle-watering wells) are not near known sources of groundwater contamination and contamination has not migrated to the depths of the deep water-supply wells. In addition, water-supply wells near currently existing plumes (at the High Explosive Melt/Pour Facility, the TNT Washout Facility, and the Old Burning Grounds) have been tested during environmental investigations and found to be free from contamination. According to available sampling results, contamination has not migrated off site. Therefore, ATSDR has concluded that no one has drunk or is drinking contaminated groundwater.

    Future Exposure

    As stated above, future off-site migration of contamination is unlikely, but cannot be ruled out, due to seasonal reversal of shallow groundwater flow and unpredictable migration in fractured bedrock. Contamination of on-site wells is possible due to horizontal and/or vertical migration. (Vertical contamination can occur via water-supply well shafts if well casings are compromised.) Therefore, monitoring of plumes and in-use water-supply wells at the installation is recommended to ensure the safety of drinking water supplies. In addition, further characterization of possible groundwater contamination is necessary at some sites. ATSDR assumes that construction of new water-supply wells will not take place until assessment and remediation of groundwater is complete and that adequate monitoring will be conducted to ensure the safety of on-site and off-site drinking water supplies. Given these assumptions, ATSDR considers future consumption of groundwater to pose no apparent public health hazard. If either of these assumptions proves false, ATSDR will reconsider its evaluation.

Surface Water and Sediment

Conclusions

Past and current exposures to surface water and sediment do not present a hazard to public health. However, contamination in groundwater could migrate and reach surface waters. In addition, surface water and sediment contamination has not been fully characterized. Although limited exposure to surface water and sediment is unlikely to pose a public health hazard, additional sampling is recommended to assess any contaminant migration and confirm that no hazardous levels of contamination are present.

Discussion

Nature and Extent of Surface Water and Sediment Contamination

Some contamination, thought to be site-related, has been found in surface water and sediment on and adjacent to the installation. In the Mississippi backwater area adjacent to the Open Burning Ground (Sites 13 and 14), some metals were detected above background and above CVs, and TCE was detected below CVs, in surface water and sediment (Dames and Moore, 1994a). Low levels of 2,4,6-TNT and pesticides were found in sediment in the Apple River near Site 20, but the source of this contamination was unclear (Dames and Moore, 1990). Surface water and sediment were sampled downgradient of Sites 21/22, in Prairie Lake and Beaty Hollow. Manganese was found to be elevated above background and above its CV in surface water; several metals were found to be elevated in sediments. At Site 21 BDP, beryllium was detected slightly over its CV in sediment in a Mississippi backwater area (Dames and Moore, 1994c). Some contamination (mercury and explosives) has been detected at Sites 73 and 77, respectively; these detections require further investigation. In addition, surface water and sediment have not been systematically and thoroughly sampled throughout and adjacent to the base.

Evaluation of Potential Public Health Hazards

    Past and Current Exposures

    Past and current recreational use of and contact with surface water and sediment on and adjacent to the installation has likely resulted in minimal exposure to contamination. The only likely exposure is dermal contact with sediments and surface water during hunting, fishing, or boating. The time spent on these waters has been infrequent and of short duration (a few hours per day on a few weekends per year). Most contaminants of concern are not readily absorbed through the skin and exposure to the low levels found in surface water and sediment does not pose a health hazard. Therefore, past and current exposures to surface water and sediment do not present a hazard to public health.

    Future Exposure

    In the future, groundwater contamination (primarily from Sites 13/14 and Sites 21/22) could migrate and reach surface waters (see the Groundwater section for more information). In addition, surface water and sediment contamination has not been fully characterized. Although limited exposure to surface water and sediment is unlikely to pose a public health hazard, additional sampling is recommended to assess any contaminant migration and confirm that no hazardous levels of contamination are present.


Soil

Conclusions

Sporadic contact with soil contamination is unlikely to pose or have posed a public health hazard. However, further sampling is necessary at some sites evaluated in this PHA, specifically Sites 17, 32, 50, 69, 73, 75, and 77. ATSDR assumes that no changes in land use will occur until assessment and remediation of the areas slated for reuse are complete. Based on this assumption, ATSDR considers future exposure to contaminated soil to pose no apparent public health hazard. If this assumption proves false, ATSDR will reconsider its evaluation. ATSDR will review remediation and reuse plans when they are finalized, as well as additional data as they become available.

Discussion

Nature and Extent of Soil Contamination

Many areas of surface and subsurface soil contamination have been identified throughout the installation. Principal contaminants are explosives, PAHs, metals, solvents, and fuels. Detailed information on all sites with sampling data may be found in Table 1; information on the most contaminated sites is presented below.

Soils at two of the most highly contaminated sites, the TNT Washout Lagoons and the Fire Training Area, have been remediated. Soils at the TNT Washout Lagoons were contaminated with explosives, primarily 2,4,6-TNT, with lesser concentrations of 1,3,5-TNB, 2-amino-4,6-DNT, nitrobenzene (NB), and RDX. Soils at the Fire Training Area were contaminated with waste oils, solvents, and the byproducts of burning; contaminants included 1,2-DCE, TCE, TPH, and PAHs. Remediation of soil at the TNT Washout Lagoons was completed in 1994; remediation of soil at the Fire Training Area was completed in 1996 (SAIC, 1996a).

The Deactivation Furnace Site underwent a RCRA closure, which included removal of the deactivation incinerator, its concrete pad, and two USTs, as well as excavation and disposal or treatment and backfilling of contaminated soils. The closure was completed in 1996. EECAs have been prepared for other priority sites: the Open Burning Ground (Sites 13 and 14), the CF and CL Areas, and Sites 15 and 33 (SAIC, 1996a). Another priority site, where approximately 800 tons of dinitro-ortho-cresol were apparently buried in 1952, has been investigated, but sampling data for this site were not available at the time this public health assessment was prepared (Clarke, 1998a,b).

As noted in Table 1, soil sampling has been incomplete at the following sites evaluated in this PHA: 17, 32, 50, 69, 73, 75, and 77.

Evaluation of Potential Public Health Hazards

    Past and Current Exposures

    Past and current contact with contaminated soil was and is likely only sporadic. Because of the perimeter fence around SVADA, only SVADA workers and hunters have access to contaminated sites. Most of the known contaminated sites are currently unused. Workers at SVADA may have come into contact with chemicals during the course of their jobs, but this occupational exposure is governed by the Occupational Safety and Health Administration and various state agencies. Thus, past and current exposures to soil contamination pose no apparent public health hazard.

    Future Exposure

    ATSDR assumes that no changes in land use will occur until assessment and remediation of the areas slated for reuse are complete. Based on this assumption, ATSDR considers future exposure to contaminated soil to pose no apparent public health hazard. If this assumption proves false, ATSDR will reconsider its evaluation. ATSDR will review remediation and reuse plans when they are finalized, as well as additional data as they become available.


Uptake of Contaminants by Livestock, Wildlife, and Aquatic Biota

Conclusions

ATSDR concluded that cattle at SVADA are unlikely to consume contaminants at levels that would pose a public health hazard to people consuming their meat. Given the available site evidence and the findings of studies conducted in similar settings and situations and other ammunition plants, ATSDR considers the consumption of game from SVADA to be no apparent public health hazard. The consumption of fish caught in the waters in or near SVADA is unlikely to pose a public health hazard, but because reliable data are not available, ATSDR considers the consumption of those fish an indeterminate public health hazard.

Discussion

Some people hunt deer and small game on the SVADA property and fish in water bodies on and adjacent to the installation. In addition, commercial livestock are grazed at SVADA. ATSDR evaluated whether people consuming livestock, game, or fish are exposed to site-related contaminants.

Consumption of Cattle

Beef cattle are grazed on approximately 6,000 acres at SVADA, including the ammunition storage areas, the buffer areas surrounding the storage areas, and the buffer areas around the ammunition processing plants (SAIC, 1997b). Water for cattle is provided by sloughs, streams, and other natural drainage features, as well as shallow wells. According to available data, none of these wells are affected by contamination. The grazing season extends from May 1 through November 1 (Dames and Moore, 1990). At present, approximately 950 head of cattle are grazed per year (Speaker, 1999).

ATSDR determined that cattle are unlikely to accumulate contaminants at levels of concern for the following reasons: many of the contaminated sites are outside of the cattle grazing area; contaminated sites within the grazing area represent a small fraction of the total acreage; cattle are grazed for only part of the year; and this grazing represents only a small part of the animals' life spans. Thus, ATSDR concluded that consumption of beef cattle grazed at SVADA poses no apparent public health hazard.

Consumption of Deer and Small Game

Deer hunting is allowed in certain areas of SVADA; permits are issued yearly. From 1972 through 1987, an average of 97 permits were issued each year and an average of 70 deer were bagged per year. More recently, 100 deer permits have been issued per year resulting in an annual harvest of 85 deer (Speaker, 1999). Hunting of small game, such as turkey, rabbits, squirrels, and waterfowl, also takes place. To assess whether consumption of deer meat or other game poses a threat to hunters or their families, ATSDR evaluated studies from a number of other military bases. Studies at ammunition plants in the United States indicate little or no accumulation of explosives in tissues of deer and other game (ATSDR, 1996). Studies at ammunition plants and elsewhere have indicated that game animals accumulate some metals (ATSDR, 1996). Because sites with metals contamination represent only a small fraction of the overall land area at SVADA and because wild game generally is only a small part of a family's diet, it is unlikely that consumption of game from SVADA poses a health hazard. ATSDR concludes that the consumption of game from SVADA presents no apparent public health hazard.

Consumption of Fish

Fish tissue sampling was done as part of the 1994 RI (Dames and Moore, 1994c) and the Open Burning Ground EECA (Dames and Moore, 1994a); however, only metals were analyzed and the method used (ICP analysis) is not accurate for all metals. While it is unlikely that the consumption of fish caught locally represents a significant fraction of anyone's diet, there is insufficient data to fully evaluate this potential pathway of human exposure to contaminants. Thus, ATSDR considers consumption of fish caught on or near SVADA to be an indeterminate public health hazard.


UXO

Conclusions

ATSDR considers UXO a potentially serious physical hazard. Possible UXO has not been fully characterized at the installation. Although physical hazards from incidental contact with UXO by recreational users are unlikely, hunters and site visitors accessing SVADA property should be apprised of the potential presence of UXO and instructed not to pick up or tamper with suspicious objects. If decisions are made to complete realty transfers involving sites with confirmed or potential ordnance before completion of measures necessary to achieve "UXO-clearance" of those sites, all available UXO-related information should be provided to recipients of transferred property as well as state and federal regulators. Precautions concerning UXO (for example, posting, clearance prior to excavation, etc.) should be taken as appropriate to planned reuse.

Discussion

Various site investigations have yielded information about the presence of UXO on the installation (SAIC, 1996a). As noted in Table 1, IRP Sites 7, 9, 13, 14, 17, 30, and 48 potentially contain UXO. In 1997, a systematic search for UXO locations was conducted via a records search and site inspections. The installation was divided into zones, which were categorized for ordnance presence as "confirmed ordnance," "potential ordnance," or "none." Of the entire installation, 2,402 acres were found to have confirmed ordnance; 10,240 acres were found to have potential ordnance, and 306 acres were found to have no ordnance (U.S. Army Corps of Engineers and Defense Ammunition Center, 1997). The report includes detailed recommendations concerning each area's suitability for transfer to private use and additional investigation or cleanup activities. The BRAC Cleanup Plan specifies that SVADA will maintain information transfer concerning UXO with state and federal regulatory representatives (SAIC, 1997a). SVADA is currently evaluating methods to characterize potential UXO before property transfer (Clarke, 1998a).

The U.S. Army Corps of Engineers has identified only 14 fatalities (associated with 10 accidents) that have occurred in the last 50 years on former U.S. military bases. The majority of these fatalities resulted from digging into or tampering with UXO (Wilcox, 1997). Thus, the likelihood of physical hazard from UXO is small. Nonetheless, there is potential hazard, and the consequences are serious. Therefore, users of the site and future owners of transferred property should be apprised of the presence of potential UXO, and measures should be taken as appropriate for planned reuse.


Radiation

Conclusions

The past storage of radioactive materials poses no public health hazard. No accidents associated with the storage of radioactive materials at SVADA have been reported. Radiological monitoring to date has identified no radiation hazards. Additional radiological monitoring will be conducted as necessary before property transfers.

Discussion

Special weapons, some containing radiologic materials, were stored in the "J" area at SVADA from the early 1960s to the early 1970s; the special weapons mission ended in 1975. Record reviews and employee interviews have not identified any accidents associated with special weapons operation and the "J" Area is no longer known to contain special weapons. Radioactive materials have also been stored at other documented locations at SVADA (SAIC, 1996a).

As a result of a land transfer proposal, a magazine used at one time for storage of radioactive materials was surveyed for radiological contamination; none was found. The BRAC Cleanup Plan states that additional radiological monitoring will be conducted as necessary before property transfers (SAIC, 1997a).


ATSDR CHILD HEALTH INITIATIVE

ATSDR's Child Health Initiative recognizes that the unique vulnerabilities of infants and children demand special emphasis in communities faced with contamination of their water, soil, air, or food. Children are at greater risk than adults from certain kinds of hazardous substances emitted from waste sites and emergency events. They are more likely to be exposed because they play outdoors and they often bring food into contaminated areas. They are shorter than adults, which means they breathe dust, soil, and heavy vapors close to the ground. Children are also smaller, resulting in higher doses of chemical exposure per body weight. The developing body systems of children can sustain permanent damage if toxic exposures occur during critical growth stages. Most importantly, children depend completely on adults for risk identification and management decisions, housing decisions, and access to medical care.

ATSDR evaluated the likelihood for children living on the post or in the neighboring communities to be exposed to installation contaminants at levels of health concern. When screening levels of contamination, ATSDR used the Environmental Media Evaluation Guidelines (EMEGs) for children, who are considered the most sensitive segment of the population. No special hazards to children were identified on the basis of the available data. However, incomplete data are available for some sites and exposure pathways. In addition, remedial plans and future use of the installation have not been finalized. When remediation and future use plans have been finalized, ATSDR will review them, along with any additional sampling data that becomes available.


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