Final Site Information Package for National Remedy Review Board ...

SITE INFORMATION PACKAGE FOR NATIONAL REMEDY REVIEW BOARD
PART A, SUMMARY
being addressed under the Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA) by other (non-EPA) agencies, primarily the U.S. Forest Service. In
the remainder of this Site Information Package, “the Upper Basin” refers solely to the area
surrounding the SFCDR.
1.2 Key Site Features and Land Use
The Upper Basin occupies approximately 300 square miles of land surface in the Panhandle
of northern Idaho (Figure A-1). The area includes the SFCDR and tributaries downstream to
the confluence of the South and North Forks of the river. The area addressed by this Site
Information Package, the FFS Report, and the forthcoming ROD Amendment extends
approximately 1 mile to the west beyond the confluence of the SFCDR and the North Fork
of the Coeur d’Alene River. Figure A-2 provides a map of the Upper Basin.
Land uses in the Upper Basin are a mix of residential, commercial, agriculture, mining,
forestry, and recreation. Much of the land is under federal management as National Forest.
In the headwater and tributary areas, predominant land uses include mining, mineral
processing, and forestry with some urban and residential development. Most people live in
communities located along the SFCDR, but there are also small communities and dispersed
residences in tributary canyons and gulches. The undeveloped areas of the Upper Basin
include upland forests and lowland floodplains with riverine and riparian areas and
wetlands. The SFCDR has been channelized along much of its reach by railroads and roads,
but its numerous tributaries still provide abundant recreational opportunities.
1.3 Contamination History and Contaminants of Concern
The Bunker Hill Superfund Site has a long history of mining and related metals-processing
activities. Mining and smelting in the Coeur d’Alene Basin began more than 100 years ago,
and the area became one of the leading silver-, lead-, and zinc-producing areas in the world.
Overall, the region surrounding the SFCDR produced over 97 percent of the ore mined in
the entire Basin. Approximately 1.2 billion ounces (34,000 tons) of silver, 8 million tons of
lead, and 3.2 million tons of zinc were produced. The Bureau of Land Management has
identified more than 1,000 mining or milling-related features in the area surrounding the
SFCDR. The metals-processing facilities included an electrolytic zinc plant, a lead smelter
plant, three sulfuric acid plants, a phosphoric acid plant, and a fertilizer plant.
As a result of past mining, milling, and smelting practices, substantial portions of the Basin
contain elevated concentrations of lead, zinc, cadmium, and other metals. Within the Upper
Basin, elevated concentrations of metals resulted primarily from the discharge or erosion of
over 62 million tons of mill tailings and other mine-generated wastes into rivers and streams
which, in turn, carried these wastes into downstream streambeds, floodplains, and
shorelines throughout the Upper and Lower Basins. Contaminated media in the Upper
Basin include surface water, groundwater, soil, and sediments. Contaminants of concern are
metals, particularly lead, arsenic, cadmium, and zinc.
1.4 Operable Units Addressed by this Action
USEPA has identified three OUs at the Bunker Hill Superfund Site. OUs 1 and 2 are located
within the Bunker Hill “Box”, a rectangular 21-square-mile area surrounding the former
A-3