A review of sediment bore samples showed some presence of ethylbenzene and creosote compounds. Three bore samples taken in each of the reservoirs indicated that the sediment contains dioxin. Two samples were above human health standards. (You can read about that toxin and its carcinogenic health impacts at www.ejnet.org/dioxin.) It is likely that the levels of dioxin could kill the benthic community or bottom ecology of the river and that a large quantity of floating organic toxic waste particles would pollute the mouth of the estuary.”

KlamBlog's June 8^th post included this statement:

If – as has been claimed – there are toxic dioxins in the dam sediment this could be a very big deal and very costly for taxpayers. PacifiCorp should not be liable for dam removal impacts they do not control; but they should not be released from liability for any toxic legacies associated with their dams and powerplants.

We stand by that statement - PacifiCorp should be responsible for any toxic legacies they have created. But as a result of this statement KlamBlog was contacted by folks at the National Marine Fisheries Service which provided two long memoranda addressed the results of dam sediment tests in general and the risk posed by dioxins in particular. Below are a few quotes from an April 8, 2008 memorandum to Steve Edmondson who is the NMFS Northern California Habitat Supervisor. The memo included numerous references to scientific literature. For copies of the memos contact Edmondson (Steve.Edmondson@noaa.gov)

Dioxin and furan compounds are not manufactured directly, but are byproducts of chemical production processes and combustion. Anthropogenic sources include waste incineration, burning of fuels (including coal and wood in power plants, gasoline and diesel by automobiles, trucks and farm equipment), chlorine bleaching of pulp and paper, synthesis and application of organochlorine pesticides, application of phenoxy herbicides, manufacture of polyvinyl chloride (PVC) and wood burning (fire places, stoves, camp fires, etc.).

Natural sources of dioxin include forest fires and volcanic activity, both of which have been prevalent in the Klamath River basin naturally. Atmospheric deposition is believed to be a major source of dioxins and furans in many watersheds.

Studies from outside the Klamath basin show that the levels found in the sediments behind the Klamath dams do not appear to be problematic.

The US Center for Disease Control has determined that a concentration of 100 pg/g of 2,3,7,8 TCCD ( a dioxin much more toxic than those found in the samples) represents the level of concern for soils in residential areas. The Klamath reservoir data is below these levels.

KlamBlog finds the NMFS memoranda to be persuasive. There are dioxins in the sediments behind some of the dams. There are a number of possible sources. But the levels of the dioxins in the sediments are below the levels which the US and other governments find to represent significant risk to humans, fish and the environment.

Supervisor Armstrong’s claims of significant risk to humans and fisheries if the dams are removed appear to have no meaningful relationship to the facts. We find it curious that none of the environmental and fishing organizations and tribes which are advocating dam removal have responded to Armstrong's claims. For example, there apparently has been no attempt to correct her commentary in the Redding Record Searchlight - no counter-commentary, no letter to the editor, nothing. We wonder what those expert media doctors working for the tribes and organizations are doing with their time.

In her commentary, Armstrong states that her conclusions are based on evaluation of the data by a “consultant”. But Siskiyou County has apparently not released this evaluation nor can it be found on their website. KlamBlog challenges Supervisor Armstrong and Siskiyou County to release their consultants report. We also invite Armstrong to address on KlamBlog the substance of the NMFS memos.

KlamBlog has criticized some dam removal advocates for playing loose with historical facts. It seems that some dam opponents are also willing to twist the facts in order to advance their objectives; Marcia Armstrong appears to be one of those people.

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It has also been pointed out to KlamBlog that our reporting indicating that much of what is behind the dams is detritus and not sediments is in error. We’ve checked the studies and confirmed our error. As a percentage of what is stored behind the dams, sediments predominate; detritus is a minor component.