SEDIMENT SAMPLES
Site Description
Sheep Creek Area
The Sheep Creek property is located 4 miles southeast of downtown Juneau on Gastineau Channel, approximately 1,000 feet southeast of the Sheep Creek estuary. The estuary is partly formed by and impacted by mine wastes and mill tailings resulting from mining and milling activities at the Gastineau Mine in the Sheep Creek watershed. Tailings associated with mining and milling in the surrounding area are suspected to be present on the Sheep Creek property and the adjacent beach.
Tailings from the Gastineau Mine were disposed of from 1912 to 1920 at the mouth of the Sheep Creek watershed where it empties into Gastineau Channel. The tailings disposal area encompasses about 50 acres of fine sediment.
In 1987, Echo Bay Mines, with plans to reopen the A-J Mine, sampled the tailings and found elevated levels of arsenic and lea The initial data collected by Echo Bay Mines prompted the USEPA to seek an additional investigation of the area. Mercury was also suspected in the tailings because of the past use of mercury amalgamation in the area. The additional environmental work ultimately included both a preliminary assessment and a site investigation by the consulting firm Ecology and Environment (E&E) that evaluated areas upgradient of the Gastineau Mine tailings (ADEC, 2014).
Summery
All samples were analyzed for total solids, total arsenic, and inorganic arsenic. A subset consisting of four samples and one field duplicate were also analyzed for total mercury and total lead.
Based on the analytical results, Sheep Creek Property sediments pose a potential exposure risk to humans from direct exposure to inorganic arsenic.
Although not evaluated, the potential for additional exposure routes to inorganic arsenic exists through the consumption of organisms (shellfish and plants) harvested from the Sheep Creek Property. Risk to ecological receptors is also indicated for inorganic arsenic.
Bernadine DeAsis, Environmental Specialist and RIDOLFI staff member sample soil.
Sampling
Sediment samples were collected from the Sheep Creek property on April 27, 2017.
Nine primary sediment samples and one field duplicate were collected from the property.
All samples were analyzed for total solids, total arsenic, and inorganic arsenic. A subset consisting of four samples and one field duplicate were also analyzed for total mercury and total lead.
Bernadine DeAsis, Environmental Specialist digs for soil samples at Sheep creek.
Sampling Locations
Overview
Analytical Results
Pose a potential exposure risk
Based on the analytical results, Sheep Creek Property sediments pose a potential exposure risk to humans from direct exposure to inorganic arsenic Although not evaluated, the potential for additional exposure routes to inorganic arsenic exists through the consumption of organisms (shellfish and plants) harvested from the Sheep Creek Property. Risk to ecological receptors is also indicated for inorganic arsenic.
Kamal Lindoff, Environmental Director and RIDOLFI staff dig for more samples at Sheep Creek.
RIDOLFI Sheep Creek Data Table
Upper Sheep Creek Area (Annex Mine Debris)
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