Heidi Blischke was accepted to present at the Society of Environmental Toxicologists and Chemistry (SETAC) North America Annual Meeting this November in Orlando, Florida. Her abstract is entitled, “Ongoing Degradation of an Organophilic Clay Amendment in a Sediment Cap 11 Years after Placement.”

Heidi will share her experience with using organophilic clay to sorb oils and prevent them from reaching the river at a former creosoting wood treatment facility on the Willamette River in Portland. This was the first time in the United States that organophilic clay had been used in a riverine setting—up until this point it had only been used in treatment plants.

View of the neon orange Willamette Cove sediment cap ACB blocks that were replaced after organoclay sampling in the fall of 2015.

View of the neon orange Willamette Cove sediment cap articulated concrete blocks that were replaced after organoclay sampling in the fall of 2015.

After the clay had been placed in the river, Heidi and her team noticed a large amount of gas production. This turned out to be methane produced by the clay, which had been degrading to its original hydrophilic bentonite form. Fortunately, the remedy at the river site was robust, with a fully encompassing barrier wall to 88 feet in the upland that prevented the ongoing migration of creosote to the river.

Sediment cores from Willamette Cove

Sediment cores from Willamette Cove

At her presentation, Heidi will discuss the best uses for organophilic clay, as it is still a good method of preventing oil from reaching the river if there is not an ongoing source of oil. In addition, once the clay degrades, it will no longer be permeable and can act more as a hydraulic barrier.

Will you be at SETAC Orlando? Hope to see you there.

Putting the organoclay in place

Putting the organoclay in place