Surface-Water Surveillance

Surface water on and near the Hanford Site is monitored to determine the potential effects of Hanford operations. Surface water at Hanford includes the Columbia River, riverbank springs, ponds located on the Hanford Site, and offsite water systems directly east and across the Columbia River from the Hanford Site. Columbia River sediments are also included in this discussion. Tables 5.3.1 and 5.3.2 summarize the sampling locations, sample types, sampling frequencies, and sample analyses included in surface-water surveillance activities during 1994. Sample locations are also identified in Figure 5.3.1. This section describes the surveillance effort and summarizes the results for these aquatic environments. Detailed analytical results are reported by Bisping (1995).

Columbia River Water

Originating in the mountains of eastern British Columbia, Canada, the Columbia River drains a total area of approximately () en route to the Pacific Ocean. Flow of the Columbia River is regulated by 11 dams within the United States, seven upstream and four downstream from the Site. Priest Rapids is the nearest dam upstream, and McNary is the nearest dam downstream from the Site. The Hanford Reach of the Columbia River extends from Priest Rapids Dam to the head of Lake Wallula (created by McNary Dam), near Richland. This Reach is the last stretch of the Columbia River in the United States above Bonneville Dam that remains unimpounded. The width of the river varies from approximately 300 m (984 ft) to 1,000 m (3,281 ft) within the Hanford Site. The Hanford Reach is currently under consideration for designation as a National Wild and Scenic River as a result of congressional action in 1988.

Pollutants, both radiological and nonradiological, are known to enter the river along the Hanford Site. In addition to direct discharges of liquid effluents from Hanford facilities, contaminants in ground water from past discharges to the ground are known to seep into the river (Dirkes 1990, DOE 1992c, McCormack and Carlile 1984, Peterson 1992). Effluents from each direct discharge point are routinely monitored and reported by the responsible operating contractor; they are summarized in Section 3.1, "Facility Effluent Monitoring." Direct discharges are identified and regulated for nonradiological constituents under the National Pollutant Discharge Elimination System. The National Pollutant Discharge Elimination System-permitted discharges at Hanford and the regulated parameters are listed in Appendix C, Table C.7.

The state of Washington has classified the stretch of the Columbia River from Grand Coulee Dam to the Washington-Oregon border, which includes the Hanford Reach, as Class A, Excellent (Ecology 1992). Water quality criteria and water use guidelines have been established in conjunction with this designation (Appendix C, Table C.1). The state of Washington and EPA Drinking Water Standards used in evaluating radionuclide concentrations in Columbia River water are provided in Appendix C, Table C.2.

Sample Collection and Analysis

at this location attributable to Hanford operations. The Richland Pumphouse is the first downstream point of river water withdrawal for a public drinking water supply. The river sampling locations and the methods used for sample collection are discussed in detail in the Hanford Site Environmental Monitoring Plan (DOE 1994c). In addition to the routine single-point intake, fixed-location monitoring stations described in the environmental monitoring plan, routine sampling was performed along cross sections of the Columbia River at the Vernita Bridge, 100-N Area, 100-F Area, old Hanford Townsite, 300 Area, and the Richland Pumphouse. The transect sampling was initiated as a result of findings of a special study conducted during 1987 and 1988 (Dirkes 1993). This study concluded that under certain flow conditions contaminants entering the river from Hanford are not completely mixed at routine Surface Environmental Surveillance Project river monitoring stations. Incomplete mixing results in a slight conservative bias in the data generated using the routine single-point sampling systems at the 300 Area and the Richland Pumphouse. The cross sections at Vernita Bridge and the Richland Pumphouse were sampled quarterly during 1994. Annual transect sampling was conducted at the 100-N Area, 100-F Area, old Hanford Townsite, and 300 Area sampling locations.

Radiological analyses of water samples collected from the Priest Rapids Dam and Richland Pumphouse monitoring stations included gamma scan, iodine-129, plutonium-238, plutonium-239,240, strontium-90, technetium-99, total alpha, total beta, tritium, uranium-234, -235, and -238. Analyses of cumulative river samples (Table 5.3.1) were performed on unfiltered samples. Analyses of filters and resins were performed on particulate and soluble fractions of Columbia River water, respectively. Alpha and beta measurements provided a general indication of the radioactive contamination. Gamma scans provided the ability to detect numerous specific radionuclides (Appendix F). Sensitive radiochemical analyses and, in some cases, special sampling techniques were used to determine the concentrations of iodine-129, plutonium-238, plutonium-239,240, strontium-90, technetium-99, tritium, uranium-234, -235, and -238 in river water during the year. Radionuclides of interest were selected based on their presence in effluent discharges or ground water near the river, and their importance in determining water quality, verifying effluent control and effluent monitoring systems, and determining compliance with applicable standards. Columbia River transect samples collected in 1994 were analyzed for both radiological and chemical contaminants (Table 5.3.1). Metals, anions, and volatile organics of interest, listed in DOE (1994c), were determined from reviews of existing surface- and ground-water data, various Remedial Investigation/Feasibility Study work plans, and preliminary Hanford Site risk assessments (Dirkes et al. 1993, DOE 1992b, Evans et al. 1992). All radiological and chemical analyses of transect samples were performed on unfiltered samples.

In addition to Columbia River monitoring conducted by the Surface Environmental Surveillance Project, nonradiological water quality monitoring was also performed by the U.S. Geological Survey (USGS) at the Vernita Bridge and the Richland Pumphouse. During 1994, USGS samples were collected along cross sections every 2 months at the Vernita Bridge and quarterly at the Richland Pumphouse. Sample analyses were performed at the USGS laboratory in Denver, Colorado for numerous physical, biological, and chemical constituents. Results of USGS monitoring activities are documented in Bisping (1995).

Table 5.3.1

Table 5.3.2

Table 5.3.3

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