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Health Risk Communication Study
From April 1999 to July 2000, the Lower Columbia River Estuary Partnership contracted with EVS Environment Consultants of Seattle, Washington to undertake a study to assess two health risk areas of concern in the lower Columbia River; the bacteriological quality of the water and the possible contamination of fish by toxic chemicals. The evidence for these concerns involves the following findings:
- Significant sediment contamination in the lower Willamette River:
- Toxic contamination in some fish flesh and in sediments in the lower Columbia River.
- Documented exceedances of bacteriological standards at some sites on lower Willamette and Columbia Rivers.
The assessment focused on evaluating trends, pinpointing trouble spots, identifying gaps in the data, locating possible sources of contaminants, and identifying at risk populations. The goals of the assessment were to: 1) develop the best possible information on the current status of the health risks associated with contaminated fish and bacteria contamination; and 2) disseminate this information to the public through a community outreach strategy which targets at risk populations
The bacteriological data collected within the Estuary Partnership study area from 1990-1999 were collected from 47 different stations. The number of samples analyzed for indicator bacteria varied considerably as did the sampling methods, analytical methods, laboratories, and quality assurance/quality control procedures. Trend analysis requires consistent sampling over a number of years. As a result, only a few stations on the lower Columbia have sufficient bacteriological data to evaluate. With respect to fecal coliform bacteria, 4 sites were evaluated with no significant trends detected although there was some evidence of higher concentrations in fall and winter. For Enterococci, only one station on the Columbia had enough data to analyze and it showed no trends. For Escherichia Coli, only one station had sufficient data and no trends were apparent. For Streptococci, two stations had data but no trends were apparent except for some seasonal variability. Of the 47 stations of the lower Columbia and lower Willamette, 14 showed exceedance of one or more state standards on one or more occasions. Most of those were in the Willamette. No trends in exceedances were apparent on the Columbia.
Since the completion of the report, the Estuary Partnership has increased ambient monitoring activities on the lower Columbia River with addition of 3 new ambient sites. Bacterial concentrations are now monitored every other month at four sites on the lower river.
The available data on contaminants in fish come from a variety of different studies with different objectives and different methods. Since most of the studies were not focused on the risks to humans from consuming contaminated fish, the data is of limited use for this study. In 1996, Tetra Tech performed a human health risk analysis and identified four primary contaminants of concern: arsenic, mercury, PCBs and dioxins/furans. The analysis of the available data related to these four contaminants for the period 1990- 1999 showed too little consistency to allow any type of formal trend analysis. Further evaluation of the trend information will require that data collection must focus on species and size classes that are caught and eaten by sport and subsistence fishers in the region. Consistency of sampling frequency, location, sampling methods, laboratory methods, and target species from several trophic guilds would all be critical elements in such a study.
The Estuary Partnership addressed this issue in its long term monitoring strategy which proposes comprehensive monitoring of the fate and effects of contaminants. The strategy will be implemented as funds become available.
EVS identified target populations for water contact and for fish consumption and then identified audiences with potential risk from exposure to bacteria and from fish consumption. People with direct water contact such as swimmers and other recreationists face the greatest risk from bacterial exposure and subsistence fishers face the greatest risk from fish contamination. An extensive phone survey was conducted to learn more about who is at risk and to develop a contact base for future risk communication efforts. A variety of possible communication techniques are discussed and some areas of future information needs are identified.
The Estuary Partnership will use the extensive contact list developed through this effort to improve its communication and coordination with populations at risk and to target future messages regarding health risks. Copies of the reports from this study are available from the Estuary Partnership.
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