Dames & Moore, 1999 - USDA Forest Service
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Dames & Moore, 1999 - USDA Forest Service

Dames & Moore, 1999 - USDA Forest Service Dames & Moore, 1999 - USDA Forest Service

fs.usda.gov
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' Ingestion of Fish. Some ingestion of Site-related constituents could occur if recreational users (i.e., fishermen) eat the fish caught in Railroad Creek or Copper Creek. This.route is evaluated; however, exposure to Site constituents in fish is expected to be minimal based on the small number of fish caught in the mine influenced areas that are later consumed. Fish may also be ingested fiom Railroad Creek at Lucerne or from Lake Chelan. \ Ingestion of Groundwater. Ingestion of ground water at the Site is not considered a viable exposure route. However, because USFS personnel utilize a well downgradient of the Site, this exposure route is evaluated for the Lucerne well in this assessment. Under certain limited circumstances there could be incidental ingestion of groundwater at the Site, such as during a construction scenario. However, exposure under these circumstances would be considered insignificant considering the likelihood of such scenarios occurring and the length of exposure should such an activity occur. Dermal Absorption Through Soil, Tailings or Sediment. The dermal exposure route is complete; however, exposure related to dermal absorption was eliminated since this pathway was considered insignificant as compared with risk through ingestion. For dermal exposure to solid media (i.e., sediments, soil, and tailings) to be equal to or greater than the risk posed by ingestion, the absorption fraction, which is an indication of the amount of compounds of concern absorbed through the skin, must be greater than 0.1 (USEPA, 1992a). The absorption fraction is estimated on a compound of concern- specific basis and is dependent upon a compound of concern's permeability coefficient in addition to its soiuwater partition coefficient. For inorganics, the absorption fraction can be assumed to range from 0.001 to 0.01. (similar to experimental values for cadmium). For PCBs, the absorption fraction can be assumed to range from 0.006 to 0.06 (similar to experimental values for 3,3',4,4'-tetrachlorobiphenyl). As a result, the dermal exposure route' for solid media was considered insignificant and thuS eliminated from the preliminary exposure pathways model. Dermal Absorption Through Surface Water and Groundwater. The dermal exposure route is complete for surface water (i.e., Railroad and Copper Creeks, the sauna, seeps. mine portal drainage); however, exposure related to dermal absorption was eliminated. For dermal exposure in water to be equal to or greater than the risk posed by ingestion of those media, the permeability coefficient for the chemical from the compound of concern through skin must be greater than 0.1 cmhr (USEPA, 1992a). For inorganics, the permeability coefficient used to estimate dermal exposure is normally assumed to be 0.001 cmhr, which is two orders of magnitude less than the 0.1 cmhr level referred to above. Organics have not been detected in aqueous media. As a result, the dermal exposure route for surface water was eliminated fiom the preliminary exposure pathways model. Potential Human Receptor Populations The potential human receptors for the Site were identified based on the land use characteristics. The primary receptors were identified as Holden Village residents, recreational users of the mine area (i.e., an infrequent visitor to the Site such as a hiker or tourist), and USFS personnel utilizing the Lucerne bell G:\~W~UlaIdm.2\ni7-O-Odoc 7-12 17693-005-019Uuly .27.1999:5:16 PM;DRAFT FINAL RI REPORT

and the USFS guard station. Holden Village visitors are likely to be exposed to Site-related constituents. but were not evaluated in this assessment since cleanup levels established for Holden Village residents will be health-protective of occasional visitors. Summary of Exposure Pathways Evaluated in screening Level Assessment The exposure pathways evaluated in the screening level human health assessment are summarized below by receptor population: Resident Ingestion Surface soil (village) Surface soil (maintenance yard) Home-grown produce Inhalation Suspended particulates (tailings or soil) Recreational User Ingestion Surface soil (baseball field lagoon) Tailings Surface water Sauna dipping pool (Copper Creek diversion) Seeps 1500-level main and ventilator portal drainages Sediment Fish Inhalation Suspended particulates (from tailings) USFS Personnel Ingestion Surface soil Groundwater Inhalation Suspended particulates 7.13.2 Data Evaluation Criteria A conservative screening approach was applied to identify site-specific IHSs: maximum detected concentrations were compared to the data evaluation criteria discussed below. Those constituents with maximum concentrations below the data evaluation criteria were eliminated as IHSs. If all constituents were present at levels below the data evaluation criteria for a specific media and location, exposure to this mediajlocation was considered insignificant.. Essential Nutrients If the constituent was considered an essential nutrient, it was eliminated as an IHS. This approach is consistent with USEPA risk assessment guidance (USEPA, 1989) and MTCA (WAC 173-340-708[2][b][i]). The following are considered essential nutrients for the purposes of this screening: Calcium Iron Magnesium Potassium Sodium c:\vpdam~~~cponab~dtn-~\ri\l-f~doc -- 17693-0054l9Uuly 27.1999;5:16 PM:DRAFT FINAL RI REPORT

and the USFS guard station. Holden Village visitors are likely to be exposed to Site-related constituents.<br />

but were not evaluated in this assessment since cleanup levels established for Holden Village residents<br />

will be health-protective of occasional visitors.<br />

Summary of Exposure Pathways Evaluated in screening Level Assessment<br />

The exposure pathways evaluated in the screening level human health assessment are summarized below by<br />

receptor population:<br />

Resident Ingestion Surface soil (village)<br />

Surface soil (maintenance yard)<br />

Home-grown produce<br />

Inhalation Suspended particulates (tailings or soil)<br />

Recreational User Ingestion Surface soil (baseball field lagoon)<br />

Tailings<br />

Surface water<br />

Sauna dipping pool (Copper Creek diversion)<br />

Seeps<br />

1500-level main and ventilator portal<br />

drainages<br />

Sediment<br />

Fish<br />

Inhalation Suspended particulates (from tailings)<br />

USFS Personnel Ingestion Surface soil<br />

Groundwater<br />

Inhalation Suspended particulates<br />

7.13.2 Data Evaluation Criteria<br />

A conservative screening approach was applied to identify site-specific IHSs: maximum detected<br />

concentrations were compared to the data evaluation criteria discussed below. Those constituents with<br />

maximum concentrations below the data evaluation criteria were eliminated as IHSs. If all constituents<br />

were present at levels below the data evaluation criteria for a specific media and location, exposure to this<br />

mediajlocation was considered insignificant..<br />

Essential Nutrients<br />

If the constituent was considered an essential nutrient, it was eliminated as an IHS. This approach is<br />

consistent with USEPA risk assessment guidance (USEPA, 1989) and MTCA (WAC 173-340-708[2][b][i]).<br />

The following are considered essential nutrients for the purposes of this screening:<br />

Calcium<br />

Iron<br />

Magnesium<br />

Potassium<br />

Sodium<br />

c:\vpdam~~~cponab~dtn-~\ri\l-f~doc<br />

--<br />

17693-0054l9Uuly 27.<strong>1999</strong>;5:16 PM:DRAFT FINAL RI REPORT

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