In recent articles opposing the Cornwall Landfill interim action, I have raised issues concerning dioxin.  However, I realize that some people may not understand why dioxins are such a significant concern.  This is intended to provide basic facts regarding dioxin.

We are still learning about dioxin, but many informed sources consider it the most toxic substance after radioactive waste.  There is no amount of dioxin that is safe, and experts agree it is important to avoid any additional exposure.  Dioxin belongs to a group of chemicals known as “persistent, bioaccumulative toxins,” (PBTs) that are the current subject of world wide attention and action.  The Department of Ecology has stated that PBTs are the “worst of the worst.”  PBTs raise special challenges for our society and the environment because:

  • They remain in the environment for a long time without breaking down (persistent.)
  • Animals and people accumulate PBTs in their bodies. As these chemicals move up the food chain, they increase in concentration, and linger for generations in people and the environment (bioaccumulate.)
  • Exposure to PBTs has been linked to a wide range of toxic effects in fish, wildlife, and humans, including effects on the nervous system, reproductive and developmental problems, immune-response suppression, cancer, and endocrine disruption (toxic.)
  • PBTs can travel long distances and generally move easily between air, water, and span boundaries of programs, geography, and generations.

http://www.ecy.wa.gov/programs/swfa/pbt/

We receive the majority of our dioxin exposure from food because it is bioaccumulative and enters the food chain.  When dioxin contaminates our waters, fish consume contaminated plants and marine life, and we then eat the fish.  When dioxin contaminates our soil, it enters plants, which are consumed by grazing cattle, which are consumed by humans, etc, etc.  Animals with more body fat, such as salmon, or whales, generally contain higher levels of dioxin.

The EPA determined that dioxin exposure can also occur from breathing air with trace amounts of dioxin particles or vapor, absorption through skin contacting air, water, or soil, or inadvertent ingestion of soil. http://www.ecy.wa.gov/pubs/0104010.pdf  In other words, activities that will occur at the Cornwall Landfill when it is redeveloped for residential, commercial, and shoreline recreational uses and water access could result in dioxin contamination.

Washington’s dioxin standards conform to the results of a recently completed 12 year study by the EPA, which concluded that dioxins are more toxic than was previously understood.  (Of course, this appears to be the results each time a new study is conducted.)  Our dioxin standards are based on an increased one in one million risk of cancer, which is the most commonly used standard for state and federal agencies. 

However, dioxin exposure standards remain controversial for a number of reasons, including differences in contaminated sites, different testing procedures and methods of measurement, and the degree to which there should be site specific flexibility.  Because dioxin enters the environment in extremely small quantities, but is highly toxic, there can also be problems with accurate measurement.  Many tribes, state, and federal agencies advocate a cautious approach, while some industrial companies, consulting agencies, and shoreline developers advocate less restriction.

Fortunately, dioxin levels are declining.  In Bellingham Bay, the high sedimentation rate from the Nooksack River results in clean sediment covering contaminated surface sediment. However, because dioxin is persistent, and resistant to decomposition, dioxins from past releases will continue to be a significant health and environmental concern for a long time.  Therefore, there is a current emphasis on preventing new sources of dioxin from entering the environment. 

A pressing problem is how and where to dispose of contaminated materials from site cleanups and how to pay for the cleanup.  At a 2009 sediment management conference, Mike Stoner indicated the Port would have trouble paying for the costs associated with the new open water disposal standards for dioxin.  The Cornwall Landfill interim action is clearly intended to be a creative solution to this problem.  However, the cost savings the Port obtains from using the Landfill as an inexpensive upland disposal site does not outweigh the potential problems that I have discussed in prior posts.