A.59 Port of Portland, OR
EPA designated Portland Harbor a Superfund site because sediments in a stretch of the Lower Willamette River contain metals, pesticides, PCBs, petroleum products, and other contaminants at levels that threaten human health and the environment. Marine Terminal 4 is located within the Portland Harbor Superfund Site. Historically, the terminal was used for loading and unloading petroleum products, pencil pitch, liquid fertilizer, soda-ash, metals, and agricultural products.
The Port of Portland has worked closely with the Environmental Protection Agency to develop a plan to clean up contaminated sediment at marine Terminal 4 in North Portland. The first phase of that cleanup plan was successfully completed in fall 2008.
During the phase 1 work, the Port dredged 12,819 yd3 of sediment contaminated with petroleum, metals, and polycyclic aromatic hydrocarbons. With a fish diversion mesh and turbidity curtain in place, and with continuous modifications to the dredging process to reflect river bottom conditions, dredging activities met all water quality goals and were completed on time and within budget. Dredged sediment was transported by barge for disposal at a landfill near The Dalles.
Additionally, contaminated sediment in the back of Slip 3 was isolated with a capA covering over material (contaminated sediment) used to isolate the contaminants from the surrounding environment. made of an 18-inch layer of an organoclay-sand mix. The mix was placed by releasing from a clamshell bucket just above the surface. The organoclay-sand cap was covered with sand and stone armor. Dredging was not practical in this area because of concern for slope stability of a timber bulkhead.
A.59.1 Advantages and Limitations
Certain structures can make dredging nearby impractical. In this case, a timber bulkhead may have structurally failed if adjacent sediment was removed. In such areas, cappingTechnology which covers contaminated sediment with material to isolate the contaminants from the surrounding environment. can be a viable alternative.
A.59.2 References
Port of Portland and period at end of reference. http://www.portofportland.com/t4_ea_home.aspx.
Publication Date: August 2014