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Oregon Water Science Center

Water-Quality Data, Columbia River Estuary, 2004-05

By Jennifer L. Morace

U.S. Geological Survey Data Series 213

Prepared in cooperation with the Lower Columbia River Estuary Partnership and
the Bonneville Power Administration

ONLINE ONLY (download the report)
Water quality monitoring

USGS scientists collected water quality samples at several locations along the Columbia River Estuary during 2004-05, from near its most upstream end below Bonneville Dam to near the mouth of the river at the Pacific Ocean. Data from the sampling will provide baseline information needed by State and local agencies in efforts to protect and enhance the health of the estuary.

Significant Findings

Water-column samples were collected monthly at the Columbia River at Warrendale (RM 141), Beaver Army Terminal (RM 54), and the Willamette River at Portland (RM 13) to characterize water-quality conditions in the Columbia River Estuary. To further characterize water-quality conditions during low- and high-streamflow conditions, seasonal samplings were performed in August 2004 and April and August 2005. These samplings included suspended-sediment and semipermeable-membrane device (SPMD)-extract analyses and an expanded list of analytes, including wastewater compounds, pharmaceuticals, antibiotics, organochlorine compounds, polycyclic aromatic hydrocarbons (PAH), polybrominated diphenyl ethers (PBDE) and polychlorinated biphenyls (PCB). These additional samplings were performed at the three monthly sites as well as the Columbia River at Columbia City (RM 82) and near Point Adams (RM 4). The following significant findings have emerged from these data sets:

  • None of the aquatic-life or human-health benchmarks based on the U.S. Environmental Protection Agency water-quality standards were exceeded in either the Columbia or Willamette Rivers at sampling sites in this study. It is important to note, however, that the majority of compounds measured in this study do not have standards established. Just because a compound is not addressed by a standard does not mean that its presence or measured concentrations are not of concern.


  • Although concentrations of arsenic, chromium, copper, and lead were not present at levels of concern with regards to aquatic-life toxicity, sublethal effects and signs of endocrine disruption have been linked to low levels of these compounds. While chromium was only detected in the Willamette River, arsenic was found at higher concentrations in the Columbia River than in the Willamette River. The median copper concentration from each of the three monthly sampling sites was 1.0  microgram per liter, a level shown to have inhibitory effects on juvenile coho salmon.


  • Concentrations of trace elements in the Columbia River near Point Adams were elevated when compared to concentrations further upstream in the main stem and the Willamette River.


  • Of the 173 pesticides and degradation products analyzed, 29 were detected at least once, oftentimes with 2 or more compounds occurring in a sample together. Fourteen compounds were detected in the Columbia River, 25 in the Willamette River.


  • The triazine herbicides atrazine and simazine were the most frequently detected pesticides, most often in the Willamette River.


  • Eight of the 54 wastewater compounds analyzed were detected at least once, usually at trace levels. The known endocrine disruptor, bisphenol A, was detected in both the Columbia and Willamette Rivers, while the suspected endocrine disruptor, tri(2-chloroethyl)phosphate, was detected only in the Willamette River.


  • Of the 24 pharmaceuticals analyzed, acetaminophen, a common analgesic, and diphenhydramine, a widely used antihistamine, were detected in the Columbia River.


  • Three of the 49 antibiotics and degradation products analyzed were detected. Anhydroerythromycin, a degradation product of the antibiotic erythromycin, and trimethoprim, an antibiotic used both for people and in aquaculture, were detected at most sites during low-flow conditions, but at only one site during high-flow conditions.


  • Even though organochlorine compounds on suspended sediment were monitored monthly at the Beaver Army Terminal site from May 2004 to April 2005, p,p’-DDT was detected only once in October 2004 at 0.02 micrograms per gram. No other organochlorine compounds were detected.


  • During the seasonal samplings of suspended sediment at all four sites, no organochlorine compounds or PAHs were detected.


  • Of the 11 PBDE congeners analyzed, all were detected on suspended sediment, usually in trace amounts. The only quantifiable concentrations were measured near Point Adams.


  • Of the 209 PCB congeners analyzed, 102 were detected at some time on suspended sediment at the four sites, usually in trace amounts. A third of these detections were quantifiable at the Willamette River during the high-flow sampling. There were fewer PCB detections during the low-flow sampling than during the high-flow sampling.

Download the report (PDF, 255 KB) (Adobe Reader required; version 5 or higher preferred. If you do not have the Adobe PDF Reader, it is available for free download from Adobe Systems Incorporated.)


Significant Findings
Purpose and Scope
Sampling Design and Methods
Sample Collection and Laboratory Analysis
Monthly sampling
Seasonal Samplings
Reporting of Data
Quality Assurance
Types of Quality-Control Samples Used
Results of Quality-Control Data
Comparison of Data to Water-Quality Standards
Discussion of Selected Results
References Cited
Appendix A. Methods, Reporting Limits, and Analyte Information
Appendix B. Quality-Assurance Data

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