Five Island Lake

PCBS and Five Island Lake

Five Island Lake Community Liaison Committee
Newsletter #4, November 1997

Dear Fellow Residents ...
Three years ago, November, 1994, many of us attended an important meeting in the Fire Hall about the PCB situation. Two things came out of that meeting:

  • a commitment from the provincial government to clean up the PCB contamination in the Five Island Lake area
  • the formation of this Community Liaison Committee.

Our mandate is to work with the community and the government to develop a remediation plan that is environmentally sound, technically viable and acceptable to the community.

After discussions with local residents at a community meeting held on November 20, 1996, we recommended a Lake Clean-Up Strategy (see box, page 3) to deal with the PCB contaminated sediments in Five Island Lake. This strategy involves dredging a layer of sediments out of North Bay at the north end of the lake.

We presented this Strategy to Wayne Adams, Minister of Environment, and Don Downe, Minister of Transportation and Public Works in December, 1996. What's happened since then? Various tests have been carried out and a boat launch and control weir constructed. Now, very shortly, a pilot dredge test will start.

This newsletter is intended to bring you up to date. If you need more information, and especially if you are new to the area and want to know what the CLC is trying to do, please call the CLC member who lives nearest you (phone numbers on page 4).

Pilot Dredge Test Begins
Because every dredging situation is different, the next step in carrying out the Clean Up Strategy is to test the dredging and dewatering processes to see what works and what doesn't.

The Department of Transportation and Public Works has selected Laidlaw Environmental to carry out these pilot tests which will begin very soon. The purpose of the tests is:

  • to confirm that current dredging methods are effective in the Five Island Lake sediments (which are fine and full of organic material)
  • to identify special environmental controls or monitoring requirements needed during the full-scale operation
  • to identify what surveys may be needed before and after the full scale project
  • to confirm which dewatering techniques will be the most effective (when the sediments are first removed from the lake they will resemble a thin soup).

Environmental controls will be in place during the testing and different technologies will be assessed in terms of their accuracy and efficiency, and their ability to minimize the resuspension of sediments.

Laidlaw Environmental will take about ten days to move the equipment on to the site and then the actual dredging will probably start around November 17, lasting one or two weeks. The contractor will be using a conventional suction dredge with a high capacity pump, and will also test two types of dewatering equipment: a plate press and a centrifuge.

The land based equipment will be set up on the railway right-of-way and in the small parking area by the new boat launch.

Once the sediments have been dredged and dewatered they will be put in a container and stored on the site of the former salvage yard.

Full Scale Dredging: When?
Only a small amount of sediment will be removed from the lake during these tests. At this point the Committee doesn't know when full scale dredging will take place. This will depend on how smoothly the pilot test goes and when funding is committed. The earliest that full scale dredging could proceed would be spring of 1998.

Control Weir Built
As one of the environmental controls needed before any of the contaminated sediments are disturbed by dredging, a control weir has now been built across the narrow neck between North Bay and the rest of Five Island Lake. Water continues to flow through the opening in the weir but, if necessary, North Bay can now be temporarily isolated from the rest of Five Island Lake.

To build the weir the old bridge was removed. Two cribs were constructed and rockfill was extended from both sides and into the cribs. The Department is looking into the feasibility of facing the rockfill on the north side with crushed limestone to help counteract the acidity of the water.

A new bridge was then built over the narrow (3.5 metres) opening. This opening can be closed by dropping stop logs (planks of wood) into a frame on either side.

Even with the stop logs in position, the control weir would still only act as a temporary dam. Water would continue to flow into North Bay. The water level would rise, perhaps very quickly if a large rainstorm came along, and would soon start flowing over the top of the stop logs. The control weir will however provide an extra margin of safety while the sediment is being removed.

If the dredging disturbs large amounts of sediment, the first line of defence is the siltation curtains surrounding the dredge. If the curtains could not contain the resuspended sediments, the control weir could be closed. This would buy time, probably several days, during which the dredging contractor would be able to use coagulants to settle out the suspended sediments.

The weir is not absolutely water-tight. Sections of the former railway bed were constructed of rockfill which is porous. The rockfill used to construct the weir is also porous but a geotextile fabric has been incorporated into the structure to capture fine sediment particles.

Test Results So Far
When the Committee put forward its Strategy there were a number of unknowns relating to the Five Island Lake sediments and the use of different clean-up technologies. The Community Liaison Committee recommended moving ahead as quickly as possible on the surveys and tests needed to answer these questions.

The Honourable Don Downe and the Honourable Wayne Adams made an initial commitment to fund the first round of tests, including treatment tests carried out in a laboratory on small amounts of sediments. Because the results were positive, the Minister announced funding for the pilot dredging and dewatering program to try out equipment and processes on site.

So far the Department of Transportation and Public Works and their consultants, Jacques Whitford, have completed the following tasks.

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Collected More Information on North Bay
In order to be able to hire a dredging contractor and monitor their work effectively, the Department needed the following information:

  • a detailed bathymetric survey (a contour map of the lake bottom)
  • a map showing the location of any metal debris in the lake
  • an aquatic vegetation survey (some plants can pose problems for certain types of dredge units)
  • water quality sampling to provide a baseline against which to monitor the performance of the dredging contractor.

Tested Different Treatments on Sediments from North Bay
Not all types of treatment work on all types of sediments, so it was important to carry out several tests to see what will work. All the testing so far has been "bench scale": tests carried out in a laboratory using small quantities of sediment. They included:

  • evaluating the performance of coagulants which make fine suspended particles clump together and then sink to the bottom
  • testing dewatering equipment to help dry out the sediments after they have been removed from the lake
  • collecting physical information on the sediments in order to know how to move them around or store them temporarily on site
  • trying out the thermal desorption technology on North Bay sediments.

All of these tests were successful. In particular, the thermal desorption bench scale tests were so successful at separating the PCBs from the sediments, that the consultants say further testing using larger quantities of sediment is unnecessary.

Lake Clean-Up Strategy: Re-Cap
1.Dredge the contaminated sediments out of North Bay
There is no other reliable, long term method of keeping the PCBs from spreading further up the food chain and through the lake system

2.Make sure that the dredging doesn’t make things worse
Test to make sure it can be done safely and use all necessary environmental controls.

3.Investigate the viability of separating the PCBs from the dredged sediments using thermal desorption

Transporting all of the sediments (potentially enough to fill 400 dump trucks) a long distance could be prohibitively expensive and risky. Thermal desorption, a non-burn separation process (now proven to work on Five Island Lake sediments) could reduce volumes and costs significantly.

4. Treat the contents of the 49 containers on the site of the former salvage yard at the same time.
The containers were only intended to be a temporary solution, and they could be a problem if access was needed to the contaminated site beneath them. Therefore, if practical, the contents should be disposed of at the same time as dealing with the lake sediments.

5. Send the PCBs away to be destroyed off-site
Destruction through incineration at licensed facilities is the only permanent solution.

PCB Destruction: Some Changes
To ensure a permanent solution the Community Liaison Committee's Lake Clean-Up Strategy calls for dredging, dewatering, thermal desorption to separate the PCBs from the sediments, and then destruction of the PCBs.

Since the last newsletter various changes have taken place: the incinerator at Swan Hills in Alberta, which is the only licensed facility in Canada accepting out-of-province PCBs, has closed down temporarily. The US border, which has long been closed to shipments of PCBs, opened up only to close again a short time later in response to a court challenge.

So right now, if the dredging and thermal desorption were to be completed tomorrow, there would be nowhere to send the PCBs. However, no-one expects the situation to stay this way for long.

There are plans to reopen the Swan Hills facility to accept first liquids and then, early in 1998, solid materials. There are also licensed facilities in other provinces which could soon start accepting PCBs from other areas.

The two provincial departments are also continuing to watch developments in bioremediation (using microbes to treat the PCBs), but so far have not seen evidence that it works at full scale on Arochlor 1260, the type of PCB found in Five Island Lake.

The Committee will be monitoring the developments in PCB destruction and will keep you informed.

New Boat Launch
The Strategy also recognizes that some people with deeded access to Five Island Lake could no longer get to their property because boating is prohibited in North Bay (to avoid stirring up the contaminated sediments). The Department of Transportation and Public Works (TPW) has therefore constructed a new boat launch to provide alternate access. Only affected property owners have keys to the gate; the boat launch is not intended for general public use. If you have questions please contact Christopher Moir at TPW, 424-4725.

Your Community Representatives on the Five Island Lake Community Liaison Committee

Richmond Campbell, Cambrians Cove    876-7847

Andre Faubert, Lake of the Woods     876-8390

Wenda Greer, Cambrians Cove    876-0813

John Hoyt, Three Brooks     876-2722

Ken Jakeman, Lake of the Woods     876-2510

John Jardine, Five Island Lake     876-2724

Danny LeBlanc, Sheldrake Lake      876-8179

Joyce Milley, Hubley Lake Road     876-5000

Wayne Nicholson, Five Island Lake     876-2294

Murray Power, Sheldrake Lake     876-8236

Shawn Redmond, Glen Margaret    823-3068

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