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PUBLIC HEALTH ASSESSMENT

OLD NAVY DUMP/MANCHESTER LABORATORY (USEPA/NOAA)
MANCHESTER, KITSAP COUNTY, WASHINGTON


EVALUATION OF CONTAMINATION
AND EXPOSURE SITUATIONS

(Includes environmental contamination, pathways, and public healthimplications.)

Introduction: ATSDR's public health assessments are exposure, or contact driven. Chemicalcontaminants disposed or released into the environment have the potential to cause adversehealth effects. However, a release does not always result in exposure. People can only beexposed to a chemical if they come in contact with the chemical. Exposure may occur bybreathing, eating, or drinking a substance containing the contaminant or by skin (dermal) contact with a substance containing the contaminant.

The type and severity of health effects that occur in an individual from contact with acontaminant depend on the exposure concentration (how much), the frequency and/or durationof exposure (how long), the route or pathway of exposure (breathing, eating, drinking, or skincontact), and the multiplicity of exposure (combination of contaminants). Once exposureoccurs, characteristics such as age, sex, nutritional status, genetics, life style, and health status ofthe exposed individual influence how the individual absorbs, distributes, metabolizes, andexcretes the contaminant. Together these factors and characteristics determine the health effectsthat may occur as a result of exposure to a contaminant.

As a result of our site visit observations, and a review of the data currently available, weconcluded that three exposure situations pose no apparent public health hazard at this timebecause the level of contaminants that people are currently exposed to are low and not expectedto cause adverse health effects. Additionally, we determined that one situation poses no public health hazard because no one is being exposed.

I. NO APPARENT PUBLIC HEALTH HAZARDS

    ATSDR determined that currently three exposure situations exist, but present no apparentpublic health hazard: 1) fish and shellfish contamination in Clam Bay, 2) soil gas at thelandfill, and 3) soil contamination. The no apparent public health hazard classification hereindicates that there is currently no health hazard. However, if future conditions change, thesituations should be reevaluated to insure the protection of public health from contaminantspresent. Table 1 lists the details of these situations. Our detailed discussion follows.

A. Shellfish Contamination in Clam Bay

    EPA's Warning signs posted along the pier and shoreline of Manchester Annex state thatthe area is contaminated and recommend that shellfish not be consumed although a fewEPA and NOAA/NMFS employees have been reported to consume as many as 6 mealsper year. Contamination in shellfish does not pose a health hazard to those consumers. However, levels of arsenic, lead, polyaromatic hydrocarbons (PAHs), polychlorinatedbiphenyls (PCBs), and dioxins are high enough in the littleneck clams of the intertidalareas closest to the shore to present a public health hazard to subsistence consumers. Currently, no subsistence consumption of seafood is expected to be occurring from thisarea of Clam Bay because 1) low numbers of edible shellfish species in the beach areacould not support such harvesting, 2) signs posted along the beach warn againstconsuming the shellfish, and 3) site access limits use by the general public. ATSDRrecommends that shellfish harvesting remain advised against until remediation iscomplete and two consecutive sampling events (no sooner than 3 months) indicate thatfish and shellfish are not at levels of health concern.

    Salmon from the net pens and subtidal species such as the horse clam (Tresis capax),geoduck (Panope generosa), and sea cucumbers (Parastichopus californicus) did notcontain chemical contaminants at levels of health concern and are therefore consideredsafe to eat based on chemical contamination levels. [ATSDR does not evaluatebiological contamination. The State of Washington Department of Health overseesbiological contamination of shellfish in this area.] However, because final remediationplans for the landfill have not yet been determined, ATSDR recommends that engineeringcontrols be instituted to reduce the chance of sediments being stirred up in the watercolumn thus spreading contamination to areas inhabited by subtidal seafood species.

    History and Sampling: Chemical contamination from the landfill is the major cause ofshellfish contamination in Clam Bay. The 6 acre landfill was used from 1946 through1962. It was created by filling in the former tidal lagoon located adjacent to the shore(Figure 1). Waste from the area included domestic and wood trash, sludge from the firetraining area, and other waste from Puget Sound Naval Shipyard such as metallic andconstruction debris (1). Landfill wastes protrude out onto the shores of Clam Bay andrepresents a continuing source of contamination of the bay. The landfill has a man-madefill and soil cap about a foot deep and is currently owned by EPA. Over the years, tidalinfluences have eroded the shoreline which interfaces with the landfill. Previouslydisposed landfill material cover the shoreline and no distinguishable zone betweenlandfill and beach is apparent. Leachate seeps from the landfill enter the bay at severalpoints.

    Fish and shellfish tissue from Clam Bay were analyzed on two separate occasions. Thefirst by National Marine Fisheries Service in June 1994 and the most recent time as partof the U.S. Army Corps of Engineers Phase II Remedial Investigation (RI) September1995 (2). NMFS sampled native littleneck (Protothaca staminea), bentnose clams(Macoma nasuta) from the intertidal zones, and salmonids from the net pens. Commercial and experimental production of salmonids is on going in net pens suspendedin the middle of Clam Bay approximately 500 yards from shore. For the RemedialInvestigation, littleneck and horse clams from the intertidal zones and also geoduckclams and sea cucumbers from the subtidal zones of Clam Bay were sampled. Referencesamples were collected from Yukon Harbor (south of the site) and Manchester State Park(north of the site). As part of the RI, 14 samples were collected from 14 stations in clambay and the reference points (2). ATSDR determined that the list of chemicals for whichthe fish/shellfish tissue were analyzed was complete and the sampling locations andsample size were appropriate to evaluate the chemical contamination hazard of ingestingfish and shellfish in this area. See Appendix and Table A-1 for assumption, analysismethodology, and data.

    The highest concentrations of contaminants were detected in the upper intertidal zoneclosest to the shore and in species that inhabit that area. The distribution ofcontaminants is consistent with a source in the landfill which is eroded and suspended inthe zone near shore for uptake by filter feeding clams (2). There is a drastic decrease inthe contaminant levels in sediment and shellfish further from the shore. As a result, fishand subtidal shellfish did not contain chemical contaminants at levels of health concern.

    Present Situation: Currently, signs posted on the beach that state the area iscontaminated and advise against shellfish harvesting. EPA posted the signs to warnpeople about the potential hazard the chemically contaminated beach may have on edibleshellfish species that inhabit the beach area at low tide. Additionally, site access controlsrestrict use of the area by the general public although EPA and NOAA/NMFS employeeshave access to the beach and other areas.

    ATSDR evaluated consumption for recreational and subsistence populations because theSuquamish Tribe expressed concerns to ATSDR about the safety of eating seafood in thearea. Subsistence consumers are people whose diet is dependent on the seafood theycatch as their primary source of protein. The Suquamish members consider Clam Bayand other areas in Puget Sound as part of their usual and accustomed fishing grounds. We estimated consumption practices for subsistence consumers based on discussionswith only a few members of the Suquamish tribe (6).

    Based on our estimates for subsistence consumers, clams from the intertidal area containarsenic, lead, PAHs, PCBs and dioxins at levels that would pose a health hazard tosubsistence consumers. Levels of lead are high enough to pose a developmental hazardto the fetuses of pregnant women who consume shellfish solely from this area. Levels ofarsenic, PAHs, PCBs, and dioxins pose an increased cancer risk to subsistenceconsumers. (The appendix provides the details of our estimates.) Since employees ofEPA and NOAA/NMFS would eat considerably less than subsistence consumers, theyare not likely to experience any adverse health effects from eating contaminated shellfishfrom the intertidal area for the reported maximum of 6 meals per year. Becauseremediation plans for the landfill are not final, some remediation alternatives such aspartial removal of landfill material from the shoreline could actually cause morecontamination to be released into the sediments or water column. Therefore, ATSDRrecommends that Clam Bay remain closed to fish and shellfish harvesting untilremediation activities are complete and two consecutive sampling events (no sooner that3 months apart) indicate that fish and shellfish do not contain contaminants at levels ofhealth concern for subsistence or recreational consumers.

    Future Situation: There have been discussions between the U.S. Army Corps ofEngineers and the Suquamish Tribe about plans to open the area to shellfish harvestersand also to enhance the area to increase the shellfish population (6). Subtidal geoducks,sea cucumbers and salmon did not contain contaminants at levels of health concern forany consumer group and therefore, are safe to eat. However, because remediation plansfor the landfill are not final, ATSDR recommends that engineering controls be used toprevent contaminated sediments from moving to areas inhabited by the subtidal species. ATSDR is requesting to review post-remedial sampling data when they become availableto evaluate the safety of fish and shellfish.

    Because we based seafood consumption estimates for subsistence consumers ondiscussions with only a few members of the Suquamish tribe, our consumption estimatesmay not represent the actual consumption practices of the majority of the approximately400 local Suquamish members living in Kitsap County or the other subsistenceconsumers harvesting from this area. Our approach may over estimate the health hazardof consuming seafood from Clam Bay and all of Puget Sound and thus be overlyprotective for chemical exposure. We recognize that recommending the restriction ofseafood consumption may compromise much needed nutritional benefits. Therefore,ATSDR is working with the Washington Department of Health and the Suquamish Tribeto conduct a scientific consumption survey of the local members of the Suquamish Tribeto more accurately evaluate the public health hazard of eating contaminated fish andshellfish. The Suquamish tribal members could be an ideal population to survey becausethey have expressed health concerns to ATSDR and based on their subsistence practiceswould serve to represent other subsistence populations in the area.



Table 1.

No Apparent Public Health Hazard Situations
PATHWAY
NAME
CONTAMINANTSEXPOSURE PATHWAYS ELEMENTSTIMECOMMENTS
SOURCEENVIRONMENTAL
MEDIA
POINT OF
EXPOSURE
ROUTE OF
EXPOSURE
EXPOSED
POPULATION
Fish and ShellfishContamination in ClamBayArsenic, Lead, PAHs,PCBs, and DioxinsLandfill
major source
Fish and Shellfish Eating Fish andShellfish IngestionEPA, NOAA/NMFS employeeswho eat seafood from ClamBayPast Present
Future
No apparent public health hazard toemployees who consume 6 meals per yearof seafood from this area. However,contaminant levels are high enough inintertidal species to present a problem forsubsistence consumers. Subtidal speciesare not a health problem.*
Potentially Exposed:
Subsistence harvesterswho may eat contaminatedseafood
Soil Gas from theLandfill Methane gasLandfillSoil gasBuildings near thelandfillExplosion Hazard Potentially Exposed:
Workers in the buildingswhere explosive gas mayaccumulate.
FutureTo date, soil gas measurements have notdetected a hazard. However, methaneproduced naturally as the landfill materialsdecay may be forced laterally to inlandbuildings if it is prevented from movingvertically due to something such as non-porous cap placed over the landfill duringremediation.*
Soil Contamination Antimony, Arsenic,Cadmium, Chromium, Lead,Vinyl chloride. PAHs,PCBs, and Dioxins/furans Landfill and FireTraining AreaSoilLandfill and FireTraining AreasAccidental Ingestion,Inhalation, and DermalContactConstruction, Investigative,and Remediation workersPast
Present
Future
Surface soil contamination levels are toolow to pose a health hazard. Subsurfacesoil levels, even though much greater, donot pose a health hazard to workers whomay dig there because of the low frequencyand duration of exposure.

* Current plans incorporate sampling or controls to ensure that potential future situations present no apparent public health hazard.

B. Soil Gas at the Landfill

    Soil gas levels of methane were not detected during the sampling of test pits and therefore, donot currently pose a health hazard to workers. Additionally, the soil cap of the landfill allowssoil gases to escape vertically. However, methane produced naturally as the landfill materialsdecay may be forced laterally to inland buildings if a non-porous cap is placed over thelandfill during remediation. The Army Corps of Engineers will address the methane gasgeneration potential of the landfill and install engineering controls to prevent the migration of methane gas which will prevent the possibility of an explosion hazard in nearby buildings.

    During the U.S. Army Corps of Engineers Phase I and Phase II Remedial Investigation, testpits were dug into the landfill at Manchester Annex to determine the nature and extent ofcontamination from the landfill material. Instruments used to detect explosive hazards causedby methane were inserted into the landfill. Although methane was not detected in any of thetest pit samples, soil gas at the landfill mainly generated from the natural decomposition oforganic materials could theoretically reach explosive levels in enclosed spaces (8). The watertable is relatively high at the landfill, (8 - 15 feet below ground surface) maintaining its earlierproperties as a tidal lagoon (2). Thus, methane currently generated by the landfill is allowed toescape vertically through the porous soil cap especially when water fills the lower air spaces. ATSDR is concerned that any remediation plans to cap the landfill with a non-porous materialcould force methane to migrate horizontally to upland areas impacting nearby buildings andcreating an explosive hazard in confined spaces such as in breakroom cabinets or small offices. Therefore, ATSDR supports the use of engineering controls by the Army Corps of Engineerswhen a remediation alternative for the landfill is designed to prevent the possibility of anexplosion hazard in nearby buildings.

C. Soil Contamination

    Exposure to surface and subsurface soil at the landfill, fire training area, and the net depotarea do not pose a health hazard to construction, investigative, or remediation workers. When soils are disturbed, workers could be exposed to contaminants in soil by accidentallyingesting or inhaling soil particles or by direct contact of soil with the skin. Because suchexposures would be considered short in duration and frequency (less than daily for 30 years),they do not pose a health hazard. At this time, there are no future plans for land use ofManchester Annex to change to residential property. If such a change in usage is planned,ATSDR recommends that surface soils be resampled and contaminant levels re-evaluated forexposure to children.

    Presently, construction, investigative, and remediation workers who disturb underlying soilswould be the only exposed people. Contaminant concentrations vary widely with only a fewsamples at levels of health concern. These "hot spots" would not represent the overallexposure of workers. Therefore, the values were averaged and that average used for theexposure estimates (Table A-2). We used highly conservative estimates of frequency andduration of exposure. When there is uncertainty, we over-estimate rather than under-estimaterisk by a factor of 10 to 10,000. Thus, the exposure rates we calculated are highly protectiveof the public's health. See Appendix and Table A-2 for assumption, analysis methodology, anddata.

    Landfill: The U.S. Army Corps of Engineers conducted a preliminary assessment, and PhaseI and Phase II Remedial Investigation at Manchester Annex which provided extensiveinformation about the nature and extent of contamination. Levels of contaminants in surfacesoils are low and do not pose a health hazard. The landfill is capped with 1-2 feet of clean soiland is grass covered. Therefore, exposure to surface soils is unlikely. Contamination levelsare greater in the subsurface soils than in surface soils. Subsurface soils are contaminated withantimony, arsenic, cadmium, chromium, lead, vinyl chloride, PAHs, PCBs, and dioxins/furans. However, this contamination is well below ground surface, where it does not pose a healththreat. Workers exposed to subsurface soils are not likely to experience adverse health effectsfrom their exposures because average contaminant levels are low and exposures would berelatively short in duration and frequency (less than daily for 30 years). Protective clothing asrequired by the Occupational Safety and Health Agency (OSHA) will minimize any exposure.

    Fire Training Area: The fire training area (FTA) was built in 1942 of concrete structuresmade to resemble ship features and was used to train Navy personnel to extinguish ship fires(Figure 1). Trainees would practice putting out fires resembling ship fires which were set hereusing gas, diesel fuel, and waste oil. Associated with the FTA were underground storage tankscontaining gas, diesel, waste oil, fuel lines, water lines and pumps (2). Reports indicated thatthis area may have been used until the 1970s (1). The concrete structures are several storieshigh and contain sludge and dirt. A marshy bog is present within one of the structures and isseveral feet high. The 22 acres which include the Fire Training Area are owned byNOAA/NMFS.

    Environmental investigations at the fire training area detected PAHs, dioxins, PCBs, and totalpetroleum hydrocarbons in the soil with contaminant levels greatest in the subsurface soils. Levels in surface soils do not pose a health hazard to workers. Concrete structures threestories high used to simulate ship components are still in place. PAHs and dioxins/furans weremost likely generated from the burning of PCBs, waste fuels, and other organo chlorinechemicals during training exercises when the area was used (1942-1970). Contaminant levelsin subsurface soils do not pose a health hazard to workers who would incidentally ingest,inhale or dermally contact contaminated soils. Evaluation of workers' exposure to subsurfacesoil is included in the Appendix.

    Net Depot: The net depot is approximately 5 acres in size and was used in the 1940s forconstruction, repair, and storage of submarine nets made of steel cable which were suspendedin water of the coastal passes (Figure 1). These nets acted as underwater fences to protectimportant military areas from access by enemy submarines. The net depot area which contained a large concrete pad and several buildings was also used for buoymaintenance. Activities which included sandblasting, painting, and machining ceased in 1950when the area changed use to a boat storage area (1). The area currently includes the sameconcrete pad and buildings. Over the years, additional structures and a pier have been built(2). EPA now owns this area.

    Low levels of soil contaminants (total petroleum hydrocarbons and PCBs) have been detectedin both surface and subsurface soils where the net depot operated (2). There is no indicationthat migration of contaminants from this area has occurred. Because most of the area iscovered by a concrete pad and parking lot, it is not easily accessible to workers. Inaccessibilityand low contaminant level make exposure to the soil at the net depot no apparent healthhazard.

II. NO PUBLIC HEALTH HAZARD

    Even though no one is drinking contaminated groundwater, ATSDR evaluated the potentialexposure to groundwater contamination and the likelihood of adverse health effects to result fromsuch theoretical exposures to address possible concerns of nearby private well users. Wedetermined that groundwater contamination does not present a public health hazard.

    Groundwater Contamination

    Although groundwater contamination at Manchester Annex is in the shallow aquifer, no one iscurrently drinking contaminated water. Drinking water wells are located upgradient to the siteand tap the deeper Outwash Channel Aquifer. Antimony, arsenic, beryllium cadmium, lead, andbenzene were detected in the shallow aquifer at levels approximately 10 times greater thanallowable for drinking water. However, because no one is drinking this water it is not a healthhazard. Contribution of the shallow aquifer to the deeper drinking water aquifer, (OutwashChannel Aquifer) is not likely since the nature of groundwater flow is upward and out towardClam Bay. Additionally, any mixing of the aquifers would greatly reduce the contaminants tolevels that would most likely be non-detectable.

    Drinking water for EPA and the NOAA/NMFS facilities is provided by the town of Manchesterwhich gets their water from inland wells in the Outwash Channel Aquifer (7). The Navy's fuelsupply depot located south of Manchester Annex uses wells (Numbers 4, 5, and 6) which also liein the deeper Outwash Aquifer (2). These wells are currently not affected by the contaminationfrom Manchester Annex and would not likely be affected in the future due to the shallow nature of contamination and the direction of ground flow being upward and toward Clam Bay.

    Groundwater contamination at Manchester Annex lies in the shallow aquifer 10-15 feet deep(surficial fill including the landfill saturated zone). Water in the shallow aquifer is not suitable fordrinking water due to salt water intrusion (2). The major sources of contamination of the shallowaquifer come from the migration and leaching of contaminants from soils in the landfill and firetraining area. It is hard to predict whether contaminants in the shallow aquifer are decreasingbecause leaching of heavy metal contaminants from soils into the groundwater may continuepossibly due to the interaction of salt water with landfill materials may continue.

    Contamination of the shallow aquifer does not appear to be widespread. Additionally,contaminant levels do not indicate either temporal or spatial trends. Nine monitoring wells wereinstalled at the landfill and fire training area. Samples from the wells were collected in January,April, and September 1995. Four temporary well points were also installed in the landfill test pits. Samples from those test pits were collected in November 1994. Eighteen groundwater sampleswere collected from these newly dug wells and others previously installed (referred to as Navywells) wells. Samples from monitoring well 95MAN001MW003 in January 1995 containedelevated levels (10-1000 times higher than other samples and also safe drinking water levels) oftotal metals antimony (125 part per billion - ppb), arsenic (93 ppb), beryllium (4.2 ppb), cadmium(105 ppb), chromium (419 ppb), copper (3130 ppb), lead (2280 ppb), and zinc (24100 ppb). However, samples taken from that same well in subsequent months April, and September showedno elevated levels. Likewise, well 95MAN003MW004 showed elevated levels (10 times higher)for cadmium (123 ppb), chromium (28 ppb), copper (1330 ppb), lead (85 ppb), and zinc (3730ppb) as did its duplicate sample; however, previous samples (from January and April) from thatwell did not indicate elevated levels. Several variables such as rainfall/seasonal influence,heterogeneity of the landfill materials, and subtle changes in groundwater flow rate or subtletemporary directional changes may account for such variability in the data.

    Groundwater flow at Manchester Annex is in the direction of Clam Bay, which acts like a sink. The vertical gradient is generally upward which limits the likelihood that contaminants wouldmigrate to deeper groundwater zones even though at times during the sampling a minor downwardgradient was noticed (2). Increasing the potable well pumping volume and duration could alsotemporarily change the direction of groundwater flow. Such extreme conditions would onlyslightly impact the deeper Outwash Channel Aquifer (previously called the Navy Aquifer) becauseof the tremendous dilution that would occur when a small volume of low- level contaminants isadded to an enormous volume such as the Outwash Channel Aquifer. This dilution would mostlikely not be detectable because contamination was sporadic and not widespread.

    Future well development on the site could also impact the groundwater flow; however, it isunlikely that any impact would result in people drinking contaminated water at levels of healthconcern. Moreover, initial sampling of newly developed wells, as required by the State ofWashington and the Federal Clean Water Act, would ensure that no one would drink contaminatedwater at levels of health concern.



Table 2.

No Public Health Hazard Situation
PATHWAY
NAME
CONTAMINANTSEXPOSURE PATHWAYS ELEMENTSTIMECOMMENTS
SOURCEENVIRONMENTAL
MEDIA
POINT OF
EXPOSURE
ROUTE OF
EXPOSURE
EXPOSED
POPULATION
GroundwaterContamination Antimony, Arsenic, Beryllium,Cadmium, Chromium, Copper,Lead, and ZincLandfill and Fire TrainingAreaGroundwaterDrinking Water Taps IngestionNo one is exposed.FutureNo one is currently drinkingcontaminated water. Shallowaquifer may be hydraulicallyconnected to drinking waterwells; however, contaminantlevels would be non-detectable and therefore, nota health hazard.


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