BULLEN POINT RADAR INSTALLATION
(a/k/a USAF - DEWLINE SITE POW-3)
DEADHORSE, YUKON-KOYUKUK COUNTY, ALASKA
While chemical concentrations exceeded screening values, an important factor in the link between chemicals in the environment and adverse health outcomes in humans, is actual exposure to the chemicals. Due to the remote and unpopulated location of the site, exposure would only occur during those times maintenance workers, sportsmen, or subsistence hunters/fishers used the site. In addition to limited frequency of use, it is only during the three months of the year that soil and surface water aren't frozen and covered with snow, that contact with chemicals in soil and surface water could occur. Exposure to chemicals found in soil and surface water at the site would not be likely to result in adverse health effects.
The maximum concentration of Aroclor 1254 found in wipe samples taken from the floor of the transformer building may be a health concern if the building was used as a shelter, and the occupants exhibited behavior which resulted in extensive dermal contact with the most highly contaminated areas of the floor. If such conditions existed, there might be a small increase in serum PCB levels in the exposed individuals. It is not known, however, what health effects, if any, would result from a small increase in serum PCB levels.
At this time, there is not sufficient data to determine whether PCBs from the site could be impacting the biota which make up the subsistence portion of the native people's diet. PCBs were detected above Risk Based Screening Levels only at the Inside Transformer (OT04) site on the floor surface and in soil. Due to the nature of surface water movement (sheet flow), migration patterns are difficult to establish, and the determination of PCB contaminated areas may be problematic. Soil PCB values up to 5.9 mg/kg were seen in 1988, but subsequent sampling in 1993 resulted in maximum concentrations of only 0.6 mg/kg. While soil sampling to date does not indicate the spread of PCBs into the food chain, it may not be sufficient. Sediment and biota sampling would be necessary to establish whether PCBs are impacting the food chain at the installation.
There is general increasing concern about PCBs in the Arctic food chain due to the prevalence of PCBs at Arctic Circle sites. ATSDR is concerned about possible exposure to PCBs through the food chain by subsistence populations, and would be willing to evaluate sampling data analyzing PCB concentrations in the mammals, aquatic life, and birds listed in the Background section above. While this is a general concern for the Arctic Circle, there is no data at this time which would link PCBs found at the Bullen Point radar installation to any contaminated biota in the area of the site.
Currently, the most significant public health concern at the Bullen Point radar installation is the possibility of injury from activities in the areas of exposed drums and metal debris at the edge of the Old Landfill/Dump Site East (LF06), which due to the remote location and adverse climate, could cause even a minor injury to be serious. Persons accessing the shoreline along areas of exposed debris may risk lacerations or broken limbs while attempting to maneuver through the debris.
If the site were to convert to residential use at some point in the future, further evaluation of the site would be needed. Current data is not adequate to determine if public health could be impacted by the site. A source of drinking water would need to be identified and sampled to determine extent of contamination, if any. While limited consumption of biota from the area is currently occurring, it would be expected that consumption would increase if a village were situated at the site. Biota samples would be necessary to determine the bioaccumulation of contaminants and the subsequent level of human exposure. It is not known what impact contaminated sediments might have on a village population through direct contact and/or consumption of benthic organisms, but those pathways would need to be considered as well.