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In this section, exposure pathways are evaluated to determine whether people accessing or living near Port Hadlock could have been (past scenario), are (current scenario), or will be (future scenario) exposed to site-related contaminants. In evaluating exposure pathways, ATSDR identifies whether exposure to contaminated media has occurred, is occurring, or will occur through ingestion, dermal (skin) contact, or inhalation of vapors. 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. Comparison values are calculated from scientific literature available 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 adverse health effects, given a standard daily ingestion rate and standard body weight. If contaminant concentrations are greater than comparison values, ATSDR further analyzes exposure variables (for example, duration and frequency) and the toxicology of the contaminant. Figure 4 summarizes this exposure evaluation process.

ATSDR analyzed all 17 of the Port Hadlock sites to determine if they pose past, current, or potential future public health hazards. Additionally, ATSDR evaluated the concerns voiced by community members. As noted above, Site 10 and Site 21 were identified as areas posing a potential health hazard via consumption of shellfish and consumption of groundwater, respectively. One of the community concerns--consumption of contaminated shellfish along the north-northwestern shores of Marrowstone Island--was also identified as an area that might pose a health hazard. These three pathways are summarized in Table 1 and the following text.

An analysis of the other 15 Port Hadlock sites, which is summarized in Appendix A, indicates that these sites do not pose a public health hazard because (1) no site-related contaminants were present, (2) contaminant concentrations detected are too low to pose a health hazard, (3) past and current exposures to the general public have been prevented by strict security measures, (4) past and current exposures to Naval and remedial workers are infrequent and, if deemed necessary, conducted with personal protective equipment (PPE), and/or (5) affected areas have been or will be remediated (EFA Northwest 1995, 1996a, 1996b, 1996c, 1996d, 1996e 1997a, 1997b; Ecology 1998; EPA 1998; Foster Wheeler 1996a, 1996b; 1997, Navy 1996; SCS Engineers 1987; URS 1995a, 1995b, 1996a, 1996b, 1996c, 1997; WDOH 1991).

An analysis of the remaining community concerns, which are discussed in the "Community Health Concern" section, indicates that the concerns are not associated with any public health hazards.

Consumption of Contaminated Shellfish Located Adjacent to Site 10 and Along Boggy Spit

Site 10 is a 5-acre landfill that was used between the 1940s and the mid-1970s (EFA Northwest 1995; URS 1995a). Wastes reportedly disposed in the landfill include zinc sludges, waste paints, waste thinners, solvents, strippers, waste petroleum oil and lubricants, sandblasting paint residues, waste oil, batteries (carbon-zinc, lead), drums of unidentified liquid waste, bomb ordnance and incinerator ash, asbestos, submarine nets, metal parts, polyurethane resins, and residential trash (URS 1995a; WDOH 1991). Between the 1940s and 1953, wastes were burned in an incinerator and ashes and unburned materials were backfilled into the landfill. Oils, paints, thinners, and other liquid wastes were reportedly disposed in a trench located at the landfill (URS 1995b). The 1995 ROD outlined several corrective activities required for the landfill (see Appendix A).

The landfill is located on Boggy Spit and is surrounded by beaches and tidal lagoon areas (see Figure 5). Landfill contaminants (see Appendix A) have been introduced into the marine environment via erosion, surface water runoff, and groundwater discharge (Navy 1996; URS 1995b). Metal, slag, and other landfill materials have eroded onto the beach and into the area between the uplands and the beaches (Foster Wheeler 1996b; URS 1995b). At low tide, discharge from the landfill seeps into Port Townsend Bay. A variety of metals, organics, ordnance compounds, pesticides, and petroleum hydrocarbons have been detected in shellfish samples collected in the vicinity of Site 10 (Navy 1996).

    Past Exposure

As noted in "Land Use and Natural Resources," shellfish from beaches 1, 2, and 19 were harvested by a limited population until a ban was issued in 1988. According to site representatives, it is unlikely that beaches 1, 2, and 19 were used for subsistence fishing in the past. Regardless, this scenario was evaluated in case community members were visiting the beaches more frequently than site representatives realized.

Between 1987 and 1988, 28 shellfish samples were collected from areas north of Site 10 and along Boggy Spit (see Figure 6) (WDOH 1991). Species sampled included butter clams (Saxidomus giganteus), horse clams (Schizotherus nuttalli), pacific oysters (Crassostrea gigas), and little neck clams (Protothaca staminea). ATSDR evaluated the contaminants detected in these samples because they are representative of what people ate prior to the ban. ATSDR compared the maximum contaminant concentrations detected in the samples to EPA Region III Risk-Based Concentration (RBC) values (EPA 1997). (EPA Region III values were used because no standards for fish tissue are provided by EPA Region X.) Contaminants detected below EPA's RBCs were not analyzed further. For the contaminants detected above EPA's RBCs, exposure doses were calculated for three different populations: (1) subsistence fishers, who consume approximately 8.5 pounds of fish per month; (2) recreational fishers, who consume approximately 3.5 pounds of fish per month, and (3) and people who consume average amounts of fish (about 0.4 pounds per month). Exposure doses were calculated based on conservative assumptions for ingestion rates and exposure frequencies (see Table 2) (EPA 1989, 1991; FDA 1993; Toy 1996). Exposure doses were evaluated as follows:

  • Assessment of noncancer public health hazards. Exposure doses were compared to ATSDR's oral minimal risk levels (MRLs) or EPA's chronic oral reference dose (RfD) (ATSDR 1999). Doses less than these values are not expected to pose a noncancer health hazard. Estimated doses above these values do not necessarily indicate that health effects are expected to occur, but require closer examination.
  • Assessment of cancer public health hazards. Cancer "risks" were estimated by multiplying exposure doses by EPA's cancer slope factors (ATSDR 1999). Because a zero cancer risk is not possible to achieve, ATSDR often uses a range of 10-4 to 10-6 estimated lifetime cancer risk (or 1 new case in 10,000 to 1 million exposed persons), to determine whether there is a concern for cancer. This range is consistent with values adopted by EPA for cleaning up hazardous waste sites to a level not considered to contribute to excess cancer in a population.

As summarized in Table 2, estimated doses of arsenic and bis(2-ethylhexyl)phthalate (BEHP) exceeded health guidelines for subsistence fishers and recreational fishers, but not to people who might have consumed average amounts of fish. As mentioned previously, it appears that only limited shellfish harvesting took place in this area, even prior to the ban in 1988. Furthermore, the health guidelines have significant margins of safety built in. It is, therefore, unlikely that health hazards resulted from past exposures.

Arsenic. At high concentrations, arsenic (inorganic) has been shown to cause cancer in humans as well as several possible noncarcinogenic health effects (e.g., irritation of the stomach and intestines, decrease blood cell production, abnormal heart rhythm, blood vessel damage, and impaired nerve function). When exposure occurs by the oral route, the main carcinogenic effect appears to be an increased risk of skin cancer. Estimated doses for the multiple scenarios evaluated, however, were below doses reported in studies associated with adverse effects (ATSDR 1998a)1. In addition, it should be noted that recent research suggests that people have the ability to tolerate low levels of arsenic and that only 300 cases of arsenical skin cancer have been reported in the U.S. (and all primarily from occupational exposures). It is unlikely, therefore, that the levels of arsenic detected in Site 10 shellfish would increase the risk of cancer (Marcus and Rispin 1988; Stohrer 1991).

BEHP. BEHP has been shown to cause adverse health effects in laboratory animals, including birth defects, cancer, and liver damage (ATSDR 1998). Estimated doses exceeded conservative guidelines for cancer effects (for subsistence and recreational fishers). These guidelines are based on animal studies only. No conclusive evidence exists indicating that BEHP causes cancer in humans. Because estimated doses are lower than those shown to cause cancer in these studies, it is unlikely that exposure to detected levels of BEHP in shellfish is unsafe.

    Current Exposure

The current ban on shellfish harvesting activities at beaches 1, 2, and 19 reduces public health hazards by preventing consumption of potentially contaminated shellfish. Although it is impossible to conclusively state that no one is trespassing and violating the ban, the Navy's security has never reported any occurrences of trespassing (EFA Northwest 1996b). Signs are posted to inform people of the bans in these areas (EFA Northwest 1997a).

ATSDR has supported the current ban. ATSDR evaluated whether shellfishing in this area would pose a public health hazard if the ban were not in place. For this analysis, ATSDR used data collected during a May 1998 sampling event (Foster Wheeler 1999). These samples were collected as part of a monitoring program that has been developed for Site 10. Little neck clam samples were collected from ten locations (see Figure 7) and from a reference location that is thought to be relatively pristine and uninfluenced by Port Hadlock's activities. The samples were analyzed for SVOCs, pesticides, PCBs, ordnance compounds, and metals (Foster Wheeler 1999). Table 3 lists the contaminants that were detected.

"Total" arsenic was the only contaminant detected that exceeded EPA Region III RBC values. In interpreting these results, it is important to understand that the arsenic in shellfish is in both inorganic and organic forms. Organic forms are considered relatively non-toxic, but inorganic forms can cause a variety of health effects at high enough levels (see previous discussion). According to the Food and Drug Administration (FDA), inorganic arsenic only accounts for 10% of the arsenic in shellfish (FDA, 1993). In studies that ATSDR has performed near Marrowstone Island, however, only approximately 1% of the total arsenic detected in little neck clams was shown to be in inorganic forms (ATSDR 1998b; Foster Wheeler 1999).

In estimating possible exposure doses, ATSDR considered both the 1% and 10% assumption regarding the amount of inorganic arsenic, along with various assumptions for ingestion rates and exposure frequencies (see Table 4). When assuming that only 1% of the arsenic is in its more toxic inorganic form, estimated doses were shown to be too low to pose health hazards. Even assuming 10% inorganic arsenic, estimated doses only slightly exceeded health-based guidelines. As noted previously, people's ability to tolerate low levels of arsenic without experiencing adverse effects and the margin of safety built into guideline values suggest health hazards associated with exposures to detected levels of arsenic would be unlikely.

To be conservative, Tables 3 and 4 also highlight those contaminants which were listed as "nondetect," but had detection limits that exceeded their RBC. Detection limits represent the lowest concentration that an analytical instrument has the sensitivity to detect. If an instrument's detection limit is higher than an RBC, there is no way to conclusively state that the contaminant did not exceed the RBC. In a worst case scenario, these chemicals could actually be present at concentrations hovering around their detection limits. ATSDR assumed that this was the case when it estimated exposure doses for these chemicals. The results indicated that nitrobenzene and 2,4,6-trinitrotoluene doses slightly exceeded their health-based noncancer guidelines if they are assumed to be present at 1.0 ppm and 3 ppm, respectively. It is possible, however, that the contaminants are not present in the tissues at all.

    Future Exposure

There is significant public and tribal interest in reopening the beaches to shellfish harvesting (EFA Northwest, 1995; Foster Wheeler 1996a). Measures outlined in the ROD should prevent future health hazards by

  • Minimizing further contamination of the marine environment. Installation of a landfill cap and erosion protection measures (both completed in 1997) should minimize further migration of contaminants from the landfill into the marine environment (EFA Northwest 1996c; Foster Wheeler 1997).
  • Preventing human exposure to contamination. As outlined in the ROD, a shellfish monitoring plan has been implemented to ensure that future consumers are not exposed to potential health threats. Under this plan, the Navy must collect shellfish samples every other year until it is confirmed that eating these shellfish does not pose health hazards (Foster Wheeler 1996a). Once the shellfish are considered safe to eat, the beaches will be reopened to harvesting. As noted above, the first round of monitoring was conducted in May 1998 and results were released in February 1999. The results are summarized above in the "Current Exposure" section. Although the Navy concluded that no contaminants were present at concentrations that could pose health hazards, an additional round of sampling is planned to ensure that this is the case. In the subsequent sampling round, the Navy plans to analyze samples for only six organic compounds and eight inorganic compounds (Foster Wheeler 1999). Nitrobenzene and 2,4,6-trinitrotoluene are not currently included in the list of analytes. ATSDR recommends including these chemicals in future analyses and using analytical techniques that have lower detection limits. (ATSDR is making this recommendation because the detection limits used during the May 1998 sampling event for these two chemicals were above EPA Region III RBCs. As noted above, exposure doses for these two chemicals could slightly exceed health-based guidelines if the chemicals were present at their RBC levels.)

Consumption of Contaminated Shellfish Along the North-Northwestern Shores of Marrowstone Island

Areas on the north-northwestern shores of Marrowstone Island are open for shellfish harvesting. Community members are concerned that shellfish in these areas have been contaminated by Site 10. As noted in two reports, it is unlikely that Site 10 contaminants migrated to Marrowstone Island:

  • Foster Wheeler Environmental Corporation's Final Site Work Plan; Site 10 North End Landfill document indicates that Site 10 sediments accumulate in Boggy Spit and the broad underwater sandbar directly off-shore of the northeast point of Indian Island. It is unlikely, therefore, that sediments are migrating to Marrowstone Island (Foster Wheeler 1996b).
  • According to the ROD, contaminants from the landfill would be too diluted to be detected in marine environments near Marrowstone Island (URS 1995b).

ATSDR recognizes, however, that community members are concerned about Site 10 sediments migrating to Marrowstone Island. As noted in Appendix C, one community member reported that strong tides exist in the area and are capable of carrying sediment across long distances. Given the community's concern, ATSDR analyzed shellfish data along the north-northwestern coast of Marrowstone Island.

    Past Exposure

ATSDR has very limited information about who was allowed to harvest shellfish along Marrowstone Island's shores in the past. To be conservative, ATSDR assumed that subsistence fishers used the area. Only two shellfish samples were collected from Marrowstone Island's north-northwestern shores in the past. These samples (samples 18 and 23) were collected in 1993 and reported in a 1995 Remedial Investigation/Feasibility Study (RI/FS) (see Figure 8). An evaluation of the contaminants in these two samples indicated that estimated exposure doses of arsenic and pentachlorophenol were above health-based guidelines for subsistence and recreational fishers scenarios, but not for scenarios associated with eating average quantities of fish (see Table 5). Whether adverse effects would actually be associated with exposures to these chemicals is unknown. Because only two samples were collected, it is unclear whether detected concentrations are representative of the entire shoreline. As noted previously, people may have the ability to tolerate low levels of arsenic exposure. Also, the pentachlorophenol concentration that ATSDR used to evaluate health hazards is extremely conservative.2 Furthermore, pentachlorophenol has only been shown to increase the risk of cancer in laboratory animals; its effect on humans has not been conclusively determined.

    Current Exposure

Because past sampling results indicated that some contaminants were detected slightly above health-based guidelines, ATSDR conducted additional sampling to ensure that current health hazards are not occurring. In April 1998, ATSDR collected shellfish samples from 10 locations along Marrowstone Island's shores (see Figure 9) (ATSDR 1998b). In addition, ATSDR collected samples from three reference locations (i.e., locations 11, 12, and 13) that were far removed from areas of contamination. ATSDR's sampling team collected a variety of shellfish species. By doing so, the team gathered information on how contaminant concentrations differ between little neck clams, horse clams, oysters, and cockles (ATSDR 1998b). (Additional details on sample collection techniques and sample handling and documentation can be found in ATSDR's Health Consultation-Exposure Investigation, Shellfish Contamination at Marrowstone Island, Washington, Associated with U.S. Navy Port Hadlock Detachment (Indian Island Depot), dated September 22, 1998.)

Shellfish samples were analyzed for arsenic, pentachlorophenol, polycyclic aromatic hydrocarbons (PAH), and PCBs (ATSDR 1998b). Table 6 lists the constituents detected in each sample and their associated Region III RBCs. In general, detections were infrequent and low in concentration. Arsenic, benzo(a)pyrene, benzo(e)pyrene, dibenzo(a,h)anthracene, PCBs, and perylene were the only constituents detected above RBCs. To determine whether these constituents could pose a health hazard, ATSDR calculated exposure doses based on conservative assumptions for ingestion rates and exposure frequencies (see Table 7).

Subsistence fishing is not currently occurring along the coast of Marrowstone Island, but recreational fishers do fish along these shores (EFA Northwest 1997a). As depicted in Table 7, none of the constituents were detected at concentrations that could pose health hazards to recreational fishers or people who consume average amounts of fish. ATSDR concludes, therefore, that current exposure to shellfish along Marrowstone Island's north/northwestern shores is not associated with health hazards.

    Future Exposure

ATSDR does not anticipate Marrowstone Island's shellfish population to experience increased contamination as a result of future Port Hadlock influences because (1) the Final Site Work Plan; Site 10 North End Landfill document and the ROD indicate that it is unlikely that Port Hadlock contaminants have impacted Marrowstone Island, and (2) efforts have been undertaken to prevent Port Hadlock's Site 10 from contributing additional contaminants to the environment.

As a result, ATSDR assumed that data collected from ATSDR's 1998 sampling effort reflect worst case conditions. As noted under "Current Exposure," detected concentrations are not high enough to pose health hazards to recreational fishers or to those people who eat average amounts of fish. Although subsistence fishing is not currently taking place, ATSDR evaluated potential hazards to this fisher population because shellfish use patterns could change in the future. A cursory view of Table 7 suggests that arsenic concentrations could pose a cancer hazard to subsistence fishers, but a more detailed analysis indicates that health hazards are extremely unlikely. In Table 7, a potential health hazard was predicted assuming that a person eats 128 grams of Marrowstone Island's most contaminated horse clams every day for 30 years. As shown in Table 6, arsenic concentrations were much higher in horse clams (0.004-0.122 parts per million [ppm]) than they were in little neck clams (0.012-0.035 ppm), cockles (0.0152-0.0321 ppm), and oysters (0.012 ppm). In fact, calculations indicate that horse clams are the only shellfish species associated with health hazards. ATSDR believes it is unrealistic to assume that a person's diet would consist solely of horse clams every day for thirty years (ATSDR 1998b). Therefore, based on current data, ATSDR concludes that future consumption of shellfish is unlikely to pose a health hazard.

Consumption of Groundwater Potentially Impacted by Site 21

Site 21 is located immediately east of Building 86 and is approximately 5,000 square feet (see Figure 10). This area was reportedly used as a disposal site for waste oils, solvents, electrical equipment, fill soil, and paint in the 1940s (EFA Northwest 1995; URS 1995a; WDOH 1991). Contaminants were detected in the groundwater underlying Site 21 in 1995 and 1996 (see Appendix A). As a result, the 1995 ROD specified that additional groundwater monitoring needed to be conducted at Site 21. These monitoring activities have recently been completed.

The only production wells located in this area are backup water supply wells No. 1 (located 1,500 feet north of Site 21) and No. 2 (located 100 feet south of Site 21). Groundwater contamination from Site 21 (see Appendix A) might impact the water in these wells, but this has not been confirmed.

Past Exposure

Water supply wells Nos. 1 and 2 were drilled in 1941. These wells might have been used for drinking water between 1941 and 1945, but this information has not been confirmed. In addition, data are not available to assess the quality of groundwater during this time.

    Current Exposure

Backup water supply wells Nos. 1 and 2 are not currently being used and therefore do not pose a public health hazard.

    Future Exposure

Although there are no immediate plans to use these wells in the future, the possibility cannot be ignored (URS 1995a). However, if the wells are reopened in the future or if a new well is installed, it is highly unlikely that future consumption of groundwater in the vicinity of Site 21 could cause a public health hazard. As mandated by the ROD, a 2-year groundwater monitoring program was initiated to better assess the extent and degree of groundwater contamination under Site 21 (URS 1995b). The monitoring activities were recently completed and some contaminants were detected (see Appendix A) (EA 1997; Foster Wheeler 1997). The Washington Department of Ecology, EPA, and the Navy are analyzing monitoring data and groundwater reports. If these agencies decide that the contaminant concentrations pose a potential public health hazard, the following activities will be undertaken to ensure that the groundwater will not be used for drinking water in the future (Ecology 1999; URS 1995b):

  • Deed Restrictions. Deed restrictions will be put in place to prevent installation of new wells.
  • Well abandonment. Backup water supply wells Nos. 1 and 2 will be permanently abandoned.


1. Shellfish Contamination Along the Eastern Shores of Indian Island and Areas Between Indian and Marrowstone Islands

Areas along the eastern shores of Indian Island and areas between Indian and Marrowstone Islands, including Mystery Bay, are open to shellfish harvesting. ATSDR examined community suggestions that these areas could be impacted by migration of Site 10 contaminants, Site 12 groundwater discharges, and fuel leaks from ships moored between the two islands after World War II. ATSDR concludes that it is unlikely that shellfish are contaminated by these sources for the following reasons:

  • According to Foster Wheeler Environmental Corporation's Final Site Work Plan, Site 10 sediments accumulate in Boggy Spit and the broad underwater sandbar directly off-shore of the northeast point of Indian Island. It is unlikely, therefore, that sediments are migrating south (Foster Wheeler 1996b).
  • Site 12 is near the beaches along the eastern shore of Indian Island and was used for ordnance disposal in the 1940s and 1950s. Groundwater compliance monitoring data collected between 1994 and 1997 indicate that some metals are present, but at concentrations that do not pose a health hazard (Foster Wheeler 1997; URS 1997). Limited sample data (two samples) available prior to 1994 indicate that some metals were detected above the state's Model Toxics Control Act (MTCA) standards and EPA's ambient water quality criteria (URS 1996c). It is not possible to accurately predict the impact these metals might have on area shellfish, but any groundwater discharged to Kilisut Harbor is expected to be greatly diluted.
  • According to a Navy representative, none of the moored ships carried fuel (EFA Northwest 1998c). There are no environmental sampling records indicating that potential leaks from moored ships affected environmental media. In addition, the ships were removed from the harbor about 50 years ago (EFA Northwest 1996a).
  • Results from ATSDR's 1998 sampling event indicate that shellfish in Mystery Bay are not associated with health hazards. As depicted in Table 6, arsenic was the only contaminant detected in Mystery Bay's shellfish (sample location #9 in Figure 9). Concentrations were too low to pose a health hazard.

2. Drinking Water Wells Located on Marrowstone Island

Residents on Marrowstone Island report that their drinking water wells are impacted by salt water intrusion. They are concerned that Port Hadlock contaminants may be migrating across the Kilisut Harbor and affecting Marrowstone Island drinking water wells (EFA Northwest 1996c; Navy 1996). Marrowstone Island's drinking water source is not hydrogeologically connected to any other water source (EFA Northwest 1997c; EPA 1994; URS 1995b). Thus, ATSDR concludes that Marrowstone Island wells are not impacted by Port Hadlock contaminants.


ATSDR recognizes that infants and children may be more vulnerable to exposures than adults in communities faced with contamination of their air, water, soil, or food. This vulnerability results from the following factors:

  • Children are more likely to play outdoors and bring food into contaminated areas. For example, children may contact and ingest soil particles at higher rates than adults.
  • Children are shorter, which makes them more likely to breathe dust, soil, and heavy vapors that are close to the ground.
  • Children are smaller, which can result 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.

Because children depend completely on adults for risk identification and management decisions, ATSDR is committed to evaluating their special interests at Port Hadlock as part of the ATSDR Child Health Initiative.

Given tight security measures, children are not expected to contact Port Hadlock's contaminated areas. The only possible exposures to children are to contaminants that migrated to:

  • The marine environment. As noted above, Port Hadlock's Site 10 has impacted the marine environment. It is highly unlikely that children are swimming or wading in the Boggy Spit area. Although unlikely, children may have consumed contaminated shellfish from this area in the past. Current and future exposures to harmful shellfish contaminant concentrations are not expected.
  • Groundwater. Children might have consumed water from Water Supply Wells Nos. 1 and 2 between 1941 and 1944, but this information has not been confirmed. No data are available to determine whether exposures would have lead to adverse health effects.

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