Remedial Investigation of Hanford Site Releases to the Columbia River
EAS collected more than 1,100 new samples between 2008 and 2010 to measure concentrations of contaminants in aquatic media in support of DOE’s Remedial Investigation of Hanford Site Releases to the Columbia River. We sampled, evaluated, and reported on surface water and pore water, sediment, and fish. EAS led work to collect, process, and ship samples; assess sample specimen conditions, and interpret field measures and contaminant results. The EAS team safely performed this project with staff working more than 8,000 field hours and 600 boat days in, at times, extreme environmental conditions (in winter, at night). EAS successfully performed all contract requirements, including effective management of two subcontractors, on time and within budget.
Surface and Pore Water Sampling Using the Liquid-Tip Trident Probe
In response to the lack of data regarding contaminated groundwater entering the riverbeds, EAS proposed an innovative approach and performed a proof-of-principle study using an advanced groundwater upwelling mapping and sampling tool. Using this tool allowed DOE to locate and more precisely measure chemicals and radionuclides in areas of the riverbed where groundwater upwellings occur.
EAS collaborated with the liquid-tip Trident probe’s developer to tailor it specifically for the complexities of Columbia River hydrology and geology. EAS staff also performed a series of field studies and ran river flow models to develop a river-stage-specified sampling program. This was the first time river flow data had been incorporated into pore water sampling in the history of the Hanford Site. These investigations provided DOE, regulators, tribes, and stakeholders with verifiable data to make decisions on waste site and groundwater remediation actions in the Columbia River Corridor.
Sediment Sampling
The EAS team collected samples of sediment at the same locations as pore water to estimate concentrations near areas of contaminated groundwater upwellings. We adapted a split-spoon sampler to the newly developed offshore driving frame of the Trident probe to consistently collect samples within rocky substrates and in deep, fast-flowing water. In the history of Hanford Site operations, no sampling team has been able to successfully demonstrate a safe, rapid, and effective means to collect samples at these locations.
Fish Sampling. The field team collected 600 specimens of six different species of fish to assess their condition and risk to the public from consuming the fish. Fish were targeted for sampling to characterize the nature and extent of Hanford Site-related contaminants in the Columbia River and assess the risk to ecological and human health receptors that are posed by these contaminants.
EAS conducted fish sampling from just above Wanapum Dam to McNary Dam to obtain tissue samples from targeted species, including whitefish, bass, sturgeon, suckers, carp, and walleye. These fish were selected for study because they are year-round Columbia River residents, and local residents frequently catch these species. We homogenized samples at our laboratory and developed a process to quantify the amount of sediment incidentally ingested by sturgeon to better characterize radiological doses.
Specific objectives for this project were to: characterize concentrations of analytes in each target fish species and the distribution of Hanford Site-related contaminants in different parts of fish; confirm detections of target analytes in fish samples collected and analyzed during previous investigations; establish background concentrations of contaminants in fish collected from areas of the river not impacted by activities associated with the Hanford Site; estimate which areas of the river contained fish with the highest concentrations of Hanford Site-related contaminants; evaluate and summarize the variability of concentrations of contaminants within each fish species and between different species; and provide data for current and future evaluations of ecological risk.
