No data are available in documents provided by BES to characterize historical conditions for this parameter in this segment.
From 1992 to 1994, USGS (1995) conducted the Willamette River Basin Water Quality Study that collected data from the water column, suspended sediment and bed sediments throughout the Willamette River Basin. Total and dissolved chromium concentrations were not detected (<1 ug/L and <0.5 ug/L, respectively) in the two water samples collected in 1993 from the Willamette River at Linnton in the Linnton reach (USGS, 1995).
Based on documents reviewed for this study, chromium does not appear to be a parameter of concern for the Lower Willamette River.
The water samples from Linnton analyzed for chromium did not exceed water quality criteria (Tetra-Tech, 1995). USGS found that in the Willamette River basin chromium, copper, lead, and zinc were well correlated with suspended sediment concentrations. Higher concentrations of those metals were found with higher TSS concentrations. Since TSS is highly correlated with flow, USGS surmised that higher concentrations of trace elements occur during higher flow (USGS, 1996a). There are potential sources of chromium in the heavily industrialized portion of the Willamette River. Further analyses concerning specific sources and their magnitudes will be conducted as part of the Superfund evaluation (see “Areas of Concern” for further information on Superfund).