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PUBLIC HEALTH ASSESSMENT

FORT RICHARDSON (U.S. ARMY)
FORT RICHARDSON
ANCHORAGE COUNTY, ALASKA




ENVIRONMENTAL CONTAMINATION AND ENVIRONMENTAL EXPOSURE PATHWAYS

Introduction

This section examines the pathways for exposure to contamination at FortRichardson. We will examine each of the media (foodchain, soil, water,sediment, air) to determine whether contamination is present, and if people inthe community are exposed to (or in contact with) the contamination. If peopleare exposed to contamination in any of the media, we will evaluate whetherthere is enough contamination to pose a threat to people in the community. This analysis will follow the pattern depicted in Figure One, and willsystematically evaluate each of the media.

Evaluation of Possible Biota/Foodchain Exposure Pathways

General Information

The principal issue at Fort Richardson concerning possible foodchaincontamination is waterfowl contamination at Eagle River Flats (ERF). ERF is theimpact area for heavy artillery and mortars on Fort Richardson. Three generaltypes of munitions have been fired into ERF. These are high explosives (HE),illumination, and smoke (3). Of these, the principal concern for contaminationof waterfowl appears to be the smoke munitions. The two most common agentsused by the army are white phosphorous (WP) and hexachloroethane-zinc mixture(HC). About 17,000 pounds of WP were fired into ERF from 1950 to 1990. Use ofWP at ERF was discontinued in 1990 (3).

WP is the primary contaminant detected in waterfowl at ERF. The contaminationwas documented in 1990 when Army personnel and contractors determined that anannual waterfowl die-off at ERF was caused by ingestion of WP particles (4).

When WP munitions are detonated, minute particles of WP are dispersed over alarge area. The particles react spontaneously with air, forming smoke clouds. Sediment contamination at ERF was caused when unoxidized particles of WPsettled into the muddy sediments at ERF. Ducks and other bottom-feedinganimals ingest these particles during feeding. It is the consumption of thesecontaminated waterfowl that is the human exposure pathway at ERF, although itis not likely to constitute a public health hazard.

Eagle River Flats is an active firing range, therefore, access is prohibited tounauthorized personnel, including hunters. Currently extensive remediationactivities are underway at Eagle River flats to remove the white phosphorous. However, the concern was raised about movement of contaminated waterfowl toother areas where they might then be collected by hunters (4). To date, therehave been no reported public health problems that could be related toconsumption of WP-contaminated waterfowl. However, the following toxicologicalinformation is provided to evaluate the possibility of adverse public healtheffects of consumption of WP-contaminated birds.

Toxicological Evaluation of Consumption of WP-contaminated Waterfowl

After ingestion by birds, WP is distributed in numerous organs, including theskin and fatty tissue (5). The study cited in reference (5) noted that theconcentration in birds was directly related to the amounts that had beenrecently consumed, and does not appear to remain in these tissues for longerthan three days. In other words, WP does not bioaccumulate or remain in thebirds for longer than this period of time.

Army studies suggest that a lethal dose to "small" waterfowl would be in therange of 1.5 to 3.9 mg/kg (milligrams per kilograms (3). This would thereforebe the range for the upper limit on the amount of WP present in the systems ofwaterfowl that would survive to leave ERF. (A 1991 study found concentrationsof WP as high as 3,501 ppm (3,501 mg/kg) in the gizzards of dead waterfowl atERF.) Although it is possible for the duck to consume this large amount of WP,it is unlikely that it would have survived to leave ERF. Another study foundlive waterfowl with concentrations of up to 2,700 ppb (2.7 mg/kg) in varioustissue (6). This study appears to agree with the estimated range for fataldose to waterfowl as determined in (3).

During environmental evaluations, the gizzards of about 300 birds, collected byhunters offsite, were examined. No significant concentration of WP was found(3). This supports that accumulation does not occur in amounts large enough topresent a problem for consumption of birds collected offsite.

Information on human health effects of ingesting WP is based on the consumptionof amounts that are relatively much greater (for example: amounts of about oneteaspoon of WP) than would be consumed by eating contaminated waterfowl orother affected food animals. Non-cancer effects of consumption of these largeramounts of WP include stomach cramps, or kidney, heart or liver damage. Thereis no information available to suggest that WP is carcinogenic (6). WP doesnot accumulate in the body, being eliminated after several days, so that itdoes not cause problems via accumulation over time.

Little information exists on the possible adverse effects of chronic (long-term) or acute (short-term) exposure via ingestion of minute amounts (such asthose that might be found in ducks at ERF) of WP. An indication of the levelsof WP that could be ingested without significant negative health effects can befound in studies of treatment for rickets performed in 1918 and 1930. Thesestudies are cited in the ATSDR Toxicological Profile for Phosphorous (6). Children were treated for up to 26 months with doses ranging up to 0.158mg/kg/day without reported significant negative health effects. Because of thenature of these studies, the maximum amount that could be ingested with nonegative effects was not determined. However, the level of 0.158 mg/kg/day canbe taken as a very conservative lower limit, since no negative effects wereobserved. Assuming a "theoretical" 16 kg child as an example, a total of 2.58mg/day (milligram per day) of WP would equal the level of 0.158 mg/kg/day. Inother words, 2.58 mg/day could be consumed without significant negative healtheffects. Again, assuming that a maximum dose of 3.9 mg/kg would kill thewaterfowl (recognizing that WP does not stay in the system for longer thanthree days, and recognizing that death of the bird results fairly rapidly afteringestion of a lethal dose, so that higher levels are unlikely in birdscollected offsite), 3.9 mg/kg would be the maximum body burden expected in awaterfowl capable of leaving Eagle River Flats to be collected by hunters.

Without additional information on the manner that WP would concentrate in theorgans of the waterfowl, the conservative assumption is made that it is evenlydistributed throughout the edible portions of the bird.Using these assumptions,a 16 kg child could consume about 0.66 kg of WP-contaminated waterfowl per daywithout significant negative health effect.

The result for adults would be similar, with a proportional increase in theamount consumed required to account for the greater body-weight. Based onthese assumptions, a 70 kg adult could consume about 2.88 kg of WP-contaminatedwaterfowl without significant adverse health effect. Also, the lower theamount of WP present in the birds, the larger amount of contaminated tissuethat would have to be consumed for harmful effects to occur.

Finally, although high concentrations have been found in gizzards of dead duckscollected on ERF, it must be noted that the gizzard, if consumed, comprises avery small portion of the "edible" tissue. A very large number of gizzardscontaminated at this high level would have to be eaten to equal the amount of"whole duck" used in this scenario.

It must be stressed that these are very conservative assumptions and aretherefore to be regarded as very protective of public health. It is thereforeunlikely that significant human health hazard is presented by WP contaminationof waterfowl at Eagle River Flats.

Evaluation of Possible Soil Exposure Pathways

Each of the OUs contain appreciable amounts of soil contamination. Thecontaminants include petroleum and fuel products, solvents, metals, PAHs, andPCBs (2). However, there does not appear to be a significant opportunity forexposure to the public to these areas with soil contamination. OUs and sourceswithin the main cantonment area are generally secured from public access. TheOUs and source areas outside the main cantonment are also secured. Additionally, these outlying areas are remote from the public and generallyinaccessible. Further, areas determined to contain significant contaminationwill be remediated under the regulatory oversight of the state of Alaska andEPA, so that contamination will be reduced and present even less occasion forhuman contact. As a result, soil contamination at Fort Richardson is not apublic health hazard.

Evaluation of Possible Water Exposure Pathways

People can be exposed to contaminated water by drinking it, bathing or swimmingin it, or in rare cases, breathing steam vapor (for instance, in a hot shower). There are two main water pathways to consider. These pathways are:

  • groundwater, that is, water from wells, either private wells orpublic water supply wells,

  • surface water, that is, ponds, lakes, creeks, and the sediment on thebottom and along the edges of these water bodies.

Groundwater

As is the case with soil contaminants, there are a number of locations withinthe OUs that have underlying contaminated groundwater. The suite ofcontaminants is similar to that found in soils. Based on information in theInstallation Action Plan (2) and preliminary results of the remedialinvestigation activities, contaminant plumes are relatively small and arelocalized to the vicinity of the sources. As such, the plumes do not extendoutside the boundaries of the base and do not threaten off-post water wells(8). These groundwater contaminant plumes do not currently represent a threatto public water supplies. ATSDR will review RI data on groundwatercontamination, as it becomes available, to update the exposure evaluation.

Surface Water

The principal location where surface water contamination might be a concern isEagle River Flats (2,4). The presence of explosive ordnance residues and whitephosphorous in large quantities have resulted in contamination of the waters ofthis marsh area. However, these waters are not used for domestic watersupplies. Also, the potential for dermal contact with contamination is verylimited onsite, since the access to the area is prohibited. Therefore, surfacewater contamination is not a public health hazard at Fort Richardson.

Evaluation of Possible Sediment Exposure Pathways

As is the case with surface water, the primary location where contamination ofsediment is an issue would be Eagle River Flats (2, 4). And, as is the case with surface water, the potential for human exposure is extremely limited. Therefore, sediment contamination, with the current conditions, is not a publichealth hazard at Fort Richardson.

Evaluation of Possible Air Exposure Pathways

The industrial and operational activities which have occurred and which areoccurring at Fort Richardson are not the types which would result insignificant air contamination. There is no indication that these activitieshave resulted in any public health hazards. Therefore, air contamination isnot a public health hazard at Fort Richardson.

Evaluation of Possible Exposure to Physical and Other Hazards

OUs and Source Areas

The source areas for contamination are generally isolated from public contact,by fencing, signs, or paving. Additionally, the sources of contamination andOUs in outlying areas are insulated from public contact by their location ininaccessible areas of the post. Examples of these isolated areas include thePole Line Road and Roosevelt Road sites.

Eagle River Flats

As an active artillery range, Eagle River Flats is not open to public access. However, as ERF is an active artillery range, access to this area isprohibited. The area is well posted and off-limits to all unauthorizedpersonnel.

Abandoned and Derelict Structures

A group of facilities that require particular attention are the abandonedstructures throughout the post. These include buildings within the maincantonment, and facilities in more remote areas, such as the former Nikeinstallations on Summit Mountain. A number of these structures have been foundto contain asbestos in addition to the expected physical hazards of anabandoned building. During the 1994 site visit fencing at the remote Nikelocation was observed to be in a state of disrepair. Although public access tothese areas is unlikely due to the remote location within the interior of FortRichardson, these structures require continued attention in the maintenance ofinstitutional controls.

Physical Hazard Summary

As long as continued attention is given to the maintenance of institutionalcontrols, physical hazards at Fort Richardson do not represent public healththreats.

QUALITY ASSURANCE AND QUALITY CONTROL

In preparing this Public Health Assessment, ATSDR relies on the informationprovided in the referenced documents. The Agency assumes that adequate qualityassurance and quality control measures were followed with regard tochain-of-custody, laboratory procedures, and data reporting. The validity ofthe analyses and the conclusions drawn in this document are determined by theavailability and reliability of the referenced information.

The majority of the environmental data presented in this public healthassessment is from the Remedial Investigation (RI) preliminary data. Generally,the methodology used in the RI activity is appropriate for characterizingcontamination at Fort Richardson. Additional information collection is plannedduring completion of RI activities. This information will be evaluated byATSDR. Conclusions and Recommendations of this PHA will be modified ifappropriate and necessary.

COMMUNITY HEALTH CONCERNS

The issue of public health concerns was investigated by ATSDR through meetings,correspondence, telephone conversations and information from Fort Richardson,EPA, state and local agency files. Specific community public health concernshave been identified in regard to white phosphorous (WP) contamination ofwaterfowl at Eagle River Flats. Draft versions of this document were providedto the Fort Richardson, the EPA, state regulatory agencies and were provided tothe public repositories. All comments and suggested revisions wereincorporated in this final version.

In response to the concern over the potential for public health hazard fromconsuming of WP-contaminated waterfowl, an evaluation has been made of thepossibility for harm. It does not appear that significant levels of WP arefound in waterfowl offsite to present a public health hazard.


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