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. The Willamette River at Linnton in the Linnton reach was sampled in 1992 as part of Phase I of the study. Total iron concentrations in the two samples collected were 220 and 1200 ug/L, and dissolved concentrations were 80 and 370 ug/L. The Willamette River Watershed Water Quality Status and Trends Report (Aroner, 2001) evaluates the lower Willamette River water quality monitoring performed by BES, USGS, ODEQ, and other agencies from 1970 to 2001. For the evaluation, 1998 to 2000 was chosen as time period of evaluation of metals due to improvement in BES’ analytical methods for metals resulting in lower detection limits. In samples collected by BES during 1998 to 2000 at Kelly Point Park in the Confluence reach, BES did not detect dissolved iron in any of nine samples taken. Total iron concentrations ranged from 291 to 528 ug/L with a median of 381 ug/L.
The Willamette River (RM 0 to 24.8) is water quality impaired for iron (see Table 1). Iron was listed on the Oregon 303(d) list in 2002 due to exceedances of water quality criteria year round.
Iron levels at Linnton measured by USGS exceeded both aquatic life chronic toxicity and water and fish consumption human health criteria (Tetra-Tech, 1995). Total iron in BES samples from Kelly Point Park exceeded the water and fish consumption criteria. There are potential sources of iron 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).