Disposal Options for Tainted Bellingham Bay Silt

by Robyn du Prè

The Bellingham Bay Demonstration Pilot Work Group has recently released a supplemental environmental impact statement and feasibility study for the Whatcom Waterway that poses an interesting option for the disposal of contaminated sediments from Bellingham Bay.

As longtime readers will recall, the Bellingham Bay Demonstration Pilot is a multiagency effort to coordinate dredging and disposal of contaminated sediments in the bay. The pilot, established in 1996, also seeks to take advantage of the supposed efficiencies of this effort to enhance nearshore habitats in the bay.

The Bellingham Bay Demonstration Pilot effort is driven by a combination of two circumstances. The first is the Port of Bellingham’s desire to dredge the Whatcom Waterway to maintain depths needed by deep-draft vessels that have historically called at the port.

Second, and more ominous, is the existence of seven to 10 tons of mercury-contaminated sediment in the bay—an unfortunate consequence of the now-defunct Georgia-Pacific chlorine plant that operated on the waterfront from 1965 to 1999. Other contaminants also lie in the sediments of the bay, including phenolic compounds, wood waste, and other metals, such as copper.

In addition to the sediments, the pilot will address an old city dump, known as the Cornwall Avenue Landfill, located at the foot of Cornwall Avenue. This site was created when the city dumped municipal waste into the bay for many years. The site, now capped with soil, is eroding garbage and leaching contaminants into the bay.

Preferred Alternative Site Questioned
This lengthy planning exercise seemed to have culminated in October 2000 with the release of a final environmental impact statement (FEIS). In the final environmental impact statement, a “preferred alternative” for dredge and disposal was chosen. Under this alternative, the majority of the sediments in the Whatcom Waterway would be dredged and dumped into a large underwater Confined Aquatic Disposal (CAD) facility.

Other, less contaminated, sites would be capped with clean sediments. As those who have followed this project may remember, this option did not win the BayKeeper seal of approval. My concern about this Confined Aquatic Disposal option has been that the aquatic environment is fluid and dynamic and CADs around the country have not performed as well as the project proponents suggest.

As well, there are concerns about re-suspension of contaminants during dredging and bioturbation of the sediments stored in the Confined Aquatic Disposal by foraging whales and burrowing organisms. The disposal facility would be built on state-owned aquatic lands.

I have long wondered why the people of the state should have to bear the liability of mercury contamination caused by a private corporation. It would be, in my mind, akin to taking the sediments and disposing of them on national forest lands.

New Disposal Option
Regardless of the objections raised by members of the public, it seemed that this alternative would be chosen for sediment disposal. There have been, however, some significant developments in the past year that now cast this option in doubt and brings a new disposal option to light.

Last year, Georgia-Pacific announced the permanent closure of its pulp mill. Georgia-Pacific has continued to operate its tissue mill, but produces far less wastewater. Consequently, the company no longer needs the wastewater treatment capacity of its 29-acre Aerated Stabilization Basin. The Aerated Stabilization Basin is the wastewater treatment lagoon, located across the Whatcom Waterway from the mill.

In a creative move, Georgia-Pacific has offered up 21 acres of the Aerated Stabilization Basin as a disposal site for the sediments. The remaining eight acres of the lagoon would be retained as a scaled-down treatment facility for wastewater from the tissue mill.

Two Studies Have Been Written
The State Environmental Policy Act (SEPA) requires that new alternatives such as this be given the same environmental review as was given to the original alternatives in the final environmental impact statement that was issued in 2000.

To meet this requirement and more fully understand the implications of this option, a supplemental environmental impact study and supplemental feasibility study have been written.

Much of the detailed analysis needed to truly understand the implications of the new alternative is not included in the documents, but will be conducted during the design and engineering for the disposal facility. Following is a brief distillation of the supplemental environmental impact statement and feasibility study.

Preferred Remedial Action Alternative
In terms of which locations get dredged and the volume of dredge spoils needing disposal, the new alternative is very similar to the old preferred alternative, Confined Aquatic Disposal (CAD). The main difference between these two options is that under the new option, the sediments will no longer be stored in the bay, but in what is known as a “nearshore fill.”

A nearshore fill creates uplands where there was once water. For obvious reasons, it would be nearly impossible to gain the necessary permits to create a new nearshore fill today. The Aerated Stabilization Basin, however, is an existing facility, permitted and built in 1978. This offers a unique opportunity for upland disposal at a relatively low cost.

Under both scenarios, approximately 760,000 cubic yards of sediment will be dredged. Under the old alternative, mechanical clamshell dredge buckets would have been used. Dredging in this manner has the potential to re-suspend sediments as they are scooped from the bottom and then leak from the dredge buckets.

Hydraulic Dredges Instead of Clamshell Buckets
Under the new scenario, hydraulic dredges can be used. These dredges are essentially like large vacuums that suck up the sediments and pump them directly to the disposal site. It is possible to employ hydraulic dredges under this option because the disposal site (the Aerated Stabilization Basin) is adjacent to the dredge site in the Whatcom Waterway. Using hydraulic dredges will minimize re-suspension, allowing for a cleaner dredging operation.

As an aside, when RE Sources first became involved in the Bellingham Bay Demonstration Pilot, five years ago, we strongly encouraged hydraulic dredging as the environmentally preferable dredging method. I think that the use of hydraulic dredges is the best method, assuming that dredging must occur.

In addition to dredging the Whatcom Waterway, other actions will be taken under this alternative. The Aerated Stabilization Basin will be capped with clean soils once the disposal capacity has been reached.

The Georgia-Pacific log pond, the site of the highest contamination levels, was capped last year. This site was capped rather than risk re-suspension of these most contaminated sediments though dredging.

Some Sites to Be Capped
Looking elsewhere in the bay, we see that the Port of Bellingham log rafting area (a small cove at the foot of Cornwall Avenue) will be partially dredged, with spoils going to the Aerated Stabilization Basin. The site will then be capped. The Starr Rock disposal site, located off Boulevard Park, will be partially dredged to make the site more stable, and then capped.

The Harris Avenue shipyard site in Fairhaven will also be partially dredged and then capped. All of the spoils from dredging activities will find their way to the Aerated Stabilization Basin. These sites outside of the Whatcom Waterway will still need to be dredged with mechanical clamshell dredges.

The Cornwall Avenue landfill will need to be dealt with differently than under the old preferred alternative. Under the previous scenario, the landfill would have been armored by the Confined Aquatic Disposal facility.

If there is to be no aquatic disposal facility, then the site must be capped separately. The engineering of this cap will have to come under extra scrutiny because this cap must withstand the wave action on that shore.

As anyone who paddles on the bay knows, that shoreline can take quite a pounding. The continual carving of the waves caused the old cap to erode, exposing municipal waste. The old cap was never properly engineered, however, so project planners hope to do a better job of isolating the waste contained in this site.

Dredge Spoils Won’t Be Dumped Back Into Bay
The new preferred alternative looks promising: contaminated dredge spoils will not be dumped back into the bay. Upland disposal has been the option that RE Sources has pushed for all along. It also manages to find an upland disposal option that is less expensive than hauling the waste to a landfill.

The landfill option was discounted in the earlier environmental impact statement because of problems associated with de-watering and transporting sediments and the expense of disposal. The supplemental environmental impact statement quotes the cost of disposal in the Aerated Stabilization Basin as $25 million, as compared to landfill disposal at $79 million.

There are, however, still some questions about this alternative. First and foremost is the necessity of dredging in the first place. An argument could certainly be made, and has in fact been made, that dredging the waterway is unnecessary and opens the system to re-contamination, especially with the use of clamshell dredges.

Some argue that the port’s commercial docks are obsolete, as the major users of this facility were chip barges serving Georgia-Pacific and some vessels serving the Intalco facility. Neither of these facilities is operating. Just where the deep draft vessels requiring a deep waterway will come from and who they will serve is a bit of a mystery.

Maintaining Federal Navigation Channel
The port’s need to dredge to maintain this Federal Navigation Channel to authorized depths seems to be a given. My stance has long been that if they are to dredge, then they should get the contamination out of the bay.

There are other questions about the land that would be created by this nearshore fill. Yes, Georgia-Pacific would own the land (along with the contamination below the surface) and could use it for any purpose it saw fit, including the construction of buildings.

From a contamination perspective, this would be allowable because all of the sediments in the Aerated Stabilization Basin would be below the federal standards for soil contamination. According to the feasibility study, the most protective standard for allowable contamination in an upland setting is 18 mg/kg of mercury. The sediments come in at 12 mg/kg or lower.

Upland Soils v. Aquatic Sediments
This begs the question: why are these levels of contamination acceptable in upland soils but not in aquatic sediments? This is because, in an aquatic environment, the risk of bioaccumulation is greater. Marine sediments are home to a host of organisms, all of which could uptake contamination through feeding activities.

Then, the contaminants are passed up the food chain as ever-larger predators eat smaller organisms. The contaminants are concentrated at every step of the chain, causing potentially high levels in the higher order predators, of which humans are one variety.
In soils, however, the potential for bioaccumulation is less. There is the potential for direct ingestion of soil, but apparently the federal regulations have anticipated that occurrence in setting this standard, as well. The sediments in the Aerated Stabilization Basin will be capped with clean spoils before any development would take place on the site, effectively isolating the contaminants from human exposure pathways.

There is also the issue of the potential of contaminants leaching from the Aerated Stabilization Basin. The feasibility study states that Georgia-Pacific has conducted seepage monitoring of the Aerated Stabilization Basin as part of the requirements of its wastewater discharge permit.

The basin is lined with an impermeable clay liner and its integrity has apparently been confirmed by this seepage monitoring. I have not seen that data to confirm this statement, but it is made in the feasibility study.

If Kept Wet, Mercury Is Stable
As well, leaching studies indicate that the mercury is stable in the sediments, especially if kept wet. The plan is to keep the sediments in the fill perpetually wet to ensure the stability of the contaminant/sediment bonds.

Further, it should be noted that the sediments are to be pumped into the Aerated Stabilization Basin in a slurry. The flow of the slurry will have to be regulated so that the sediments will settle to the bottom and the water will then be decanted into the remaining functioning wastewater treatment area of the basin. There, further settling and treatment will occur.

The feasibility study states, and Department of Ecology staff confirm, all wastewater that is then discharged will have to meet the terms of Georgia-Pacific’s new discharge permit, to be issued soon.

This is a modified version of the National Pollution Discharge Elimination System (NPDES) permit granted to the facility a couple of years ago. The NPDES permit is being modified to reflect the drop in volume and toxicity of the effluent issuing from the facility since the pulp mill closure.

Profit From Spoils of Degradation
Lastly, one might wonder if it is fair for Georgia-Pacific to make a profit off of the spoils of environmental degradation. And, would such a development be in keeping with the city’s shoreline management program and downtown development efforts, such as they are?

These are fair questions, but my concerns here are the environmental impacts of the project, so I will leave these questions to those so inclined to ask such questions.

That’s the nutshell version of the new proposal. This alternative poses some interesting questions and does take a creative approach to a highly contentious sediment disposal issue. As a proponent of upland disposal, it has piqued my interest. As a pragmatist, I recognize that we cannot make mercury go away.


In 2002, Robyn du Prè was the North Sound BayKeeper for the environmental organization RE Sources. As baykeeper, she was an advocate and educator for marine water quality. She died in March 2015.

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