Read the full story from U.S. EPA.
The Salt Chuck Mine is a former gold, silver, copper, and palladium mine on Prince of Wales Island in the Tongass National Forest at the northern end of Kasaan Bay in southeast Alaska. The site is just under 150 acres with 97 of them being in the intertidal area of the island. Initial sampling of the site found copper as the main contaminant in the marine sediment. The high levels of copper in the sediment have impacted the invertebrate community in the adjacent mudflats and poses an ongoing ecological risk to the benthic ecology of upper Kasaan Bay. The mine is included on the Superfund National Priority List and targeted for remediation.
EPA researchers are evaluating an in situ approach for remediating the contaminated intertidal sediment. In situ approaches treat the problem “in place” on the site as opposed to excavating the material and transporting it to a landfill. To treat the contamination, EPA researchers propose using a material called biochar to amend the intertidal sediments near the mine. Biochar is a charcoal-like material that is created by slowly heating agricultural or forestry waste biomass without oxygen. Laboratory studies show that biochar is effective at sorbing copper contamination in the marine sediments and reducing its bioaccessibility. Bioaccessibility is the availability of contaminants that can be absorbed by life around it, especially marine invertebrates. Sorbing is the physical and chemical process by which one substance becomes attached to another.
Environmental News Bits 