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U.S. EPA Salt Chuck Mine -Community Update Spring 2012

Southeast Alaskas Island News of Thorne Bay, Alaska

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Last summer, the Environmental Protection Agency (EPA) collected many samples of sediment, mine tailings, clam tissue, and surface water at the Salt Chuck Mine Superfund site. We collected these samples in the intertidal area only. The Forest Service also conducted a Removal Action on the Upland part of the mine site and a report on that action should be out soon.

We did the sampling last summer to see if the site conditions have changed over the years since the Forest Service collected samples in 2002 and 2006 in the intertidal area. The information we learned from last summer's sampling will help us with the Remedial Investigation planned to start this summer. We learned some valuable information after reviewing the data we collected last summer.

First, we found an area nearby that does not appear to be contaminated by mining activity. We can now measure the existing conditions at a relatively undisturbed area to compare to the Salt Chuck Mine areas. The comparison area is in Browns Bay near Gosti Island. We collected several species of clams, sediment and surface water samples from this area.

Next, we compared all our sample results to EPA's "Screening Criteria." These are numbers we use to tell us if we need to investigate more in an area. The screening numbers do not necessarily mean that there is a toxic situation. We compare these numbers to our lab samples. These screening numbers are usually at least 10 times lower than a toxic level. We use these conservative numbers to make sure we do not miss a potential toxic source that culd effect people's health or the environment.

Our results show that out of 57 samples of sediment and tailings, half were above the screening criteria for copper and only 2 were above the criteria for arsenic. As we expected, and as the historical samples showed us, samples collected from tailings near the mill area have the highest levels of metals. The data also shows us that there was a historic deposition from the mill area, to just North and South of Unnamed Island. We found silver and mercury in only two of the 51 samples near the mill area. Each of the 31 clam tissue samples contained arsenic above screening criteria, including the "comparison samples" at Gosti Island. Only 4 samples were higher than the screening criteria for copper, and these were from soft shell clams collected closest to the mill area.

We need to consider a few things when dealing with the presence of metals like copper and arsenic on Prince of Wales Island. Obviously, with all the historic mining conducted for decades on this Island, we can assume this area is highly mineralized, compared to other parts of Alaska or the lower 48. Similarly, areas like Ketchikan and Skagway have high natural levels of metals. Also, our concern is not necessarily the amount of metal we find, but in what form. Some forms of metals are not as easily absorbed by people, plants and animals as are other forms.

Our upcoming Remedial Investigation will look at these issues and give us a more realistic picture of the possible risk to people's health and the environment. The Remedial Investigation should start in August and will include sampling the Upland part of the mine area.

I look forward to talking with you at our upcoming town meetings in Kasaan and Thorne Bay and getting your input on our Remedial Investigation plans. We hope to have these meetings in late July. I will give you as much notice as possible.

Please call or e-mail me if you have questions or want more information, or if you have information about Salt Chuck Mine that you want to share.

My telephone number is (907) 271-1271.

Copyright 2012 Southeast Alaska's Island News, Thorne Bay, Alaska. All Rights Reserved. This content, including derivations, may not be stored or distributed in any manner, disseminated, published, broadcast, rewritten or reproduced without express, written consent from SmallTownPapers, Inc.

Original Publication Date: June 6, 2012

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