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Wood Waste at Aquatic Cleanup Sites: Washington’s “Signature” Cleanup?

Posted in Cleanup & Superfund, Water Quality

Ecology recently released the Supplemental Investigation Report for the Port Angeles Harbor Cleanup. Not surprisingly, the contaminants of concern are the usual suspects associated with decades of industrial activities, including PCBs, polycyclic aromatic hydrocarbons, dioxins and metals. What is more unique about this site is that it represents what may become a hallmark of aquatic sites in the Pacific Northwest. Much of the cleanup will be driven by the need to remove or contain woody debris lying on top of sediments from decades of log rafting and mill operations.

Almost five years ago, when I was at Stoel Rives, I co-authored an article with Steve Theile and Chris Hermann on this subject. Since that article was written, Ecology has used its Model Toxics Control Act authority to compel cleanup of wood waste at various aquatic sites in Washington, not because wood waste itself is a “hazardous substance” regulated under MTCA, but because wood waste decomposes to release hazardous substances. In fact, at this point, because of the history of the forestry industry in Washington, it may be fair to say that Washington is becoming a “leader” in addressing wood waste using its cleanup authority.

Here is a picture of the sulfide distribution in Port Angeles Harbor (sulfides are produced as wood waste degrades):

Figure credit: Washington Department of EcologyWood waste is thought to cover at least 25% of the bottom of Port Angeles Harbor–over 500 acres, and not surprisingly correlates to mill areas and log rafting areas. There are five types of wood waste found in Port Angeles, logs or large wood pieces, small wood pieces or pieces of bark, very fine wood particles (pulp), traces of wood debris or particles mixed in sediment, and sparse wood pieces scattered on sediment surfaces. The detailed wood waste study for Port Angeles has more on this–including some pretty interesting pictures.

As mentioned above, wood waste degredation products can be considered hazardous substances under MTCA and can have deleterious effects on the environment. Wood waste is interesting from an ecological perspective because it can be beneficial or have adverse impacts on the ecosystem. For instance, large branches and woody debris can actually be beneficial to fish that depend on structure, such as rockfish. In contrast, fine-grained debris like sawdust can smother benthic communities, as can the same large branches and woody debris that form habitat for fish.

What to do about the wood waste? One option is to dredge the materials, but that comes at significant expense and significant ecological costs in greatly disturbing the benthic community and potentially remobilizing the other contaminants at the site. At the Port Gamble wood waste site, approximately 30,000 cubic yards of sediments with the highest concentrations of wood waste were removed, and areas with lesser amounts of wood waste are being allowed to naturally recover through degradation and sedimentation that buries the waste.

Most likely, the Port Angeles Harbor cleanup strategy for wood waste will be similar to Port Gamble. I’d expect some removal of wood waste in the form of dredging (perhaps in areas where other contaminants are co-located with wood waste) and some reliance on natural processes in other areas. I also bet that jurisdictions elsewhere will be watching as Washington continues to lead the way in addressing these types of sites.