The McCormick & Baxter Superfund site, on the shore of the Willamette River in Portland, includes 41 acres of land and 23 acres of sediments beneath the river. McCormick & Baxter Creosoting Company operated between 1944 and 1991, treating wood products with creosote, pentachlorophenol, and inorganic preservative solutions containing metals. The company discharged process wastewaters on site or directly into the river. As a result, significant concentrations of wood-treating chemicals seeped into the soil and groundwater at the site and in river sediments adjacent to the site. The U.S. Environmental Protection Agency (EPA) listed the site on the National Priorities List in 1994.
The contingency groundwater remedy was designed and implemented in 2003, consisting of a combination of steel sheet pile and soil bentonite slurry wall surrounding 18 acres of the site to prevent migration of creosote to the river. The sediment remedy, implemented in 2004, primarily consisted of an amended sand cap placed over 23 acres of contaminated sediment.
GSI’s work involved:
In 2006, GSI and our teaming partner began managing the technical elements of the project as a subcontractor to DEQ. Since then, we have implemented several complex research and monitoring projects including:
Collecting a core of the sediment cap material to evaluate the thickness and chemical composition of the organophilic clay layer.
Deployment of the passive porewater sampler
Retrieving the passive sampler