GSI conducted two focused sediment characterizations in the upriver reach of the lower Willamette River, from river mile 16 through 26. The objectives of this work to uncover (1) potential source areas in sediment that may have contributed to elevated polychlorinated biphenyl (PCB) concentrations in smallmouth bass, and (2) any previously unidentified potential source areas in the Lower Willamette watershed.
Following the surface sediment sampling effort, GSI prepared Field and Data Reports, which were approved by DEQ and the U.S. Environmental Protection Agency (EPA) in May 2018. With the exception of one location where elevated PCBs were observed, the analytical results indicated that concentrations of chemicals of concern in the upriver reach are below concentrations that would warrant active remediation.
GSI's work involved:
Marine sampling vessel
GSI and DEQ personnel collecting sediment samples
Power-grab sediment sampling