Willamette River Research Articles

Disease susceptibility of salmon exposed to polybrominated diphenyl ethers (PBDEs)

The health effects of the flame retardant polybrominated diphenyl ethers (PBDEs) in fish are not well understood. To determine the potential effects of this ubiquitous contaminant class on fish health, juvenile subyearling Chinook salmon ( Oncorhynchus tshawytscha) were fed a diet that reflected the PBDE congeners found in the stomach contents of subyearling Chinook salmon collected from the highly urbanized and industrialized lower Willamette River in the Columbia River Basin of North America. The diet, consisting of five PBDE congeners (BDE-47, BDE-99, BDE-100, BDE-153 and BDE-154), was fed to the salmon at 2% of their body weight in food per day for 40 days. Two concentrations of the diet (1× and 10× PBDE) were fed to the salmon. The 1× PBDE diet reflected the concentration of PBDEs (190 ng PBDEs/g food) found in the stomach contents of juvenile subyearling Chinook salmon; the 10× diet was prepared at 10 times that concentration. The fish were then exposed to the marine bacterial pathogen Listonella anguillarum to assess susceptibility to infectious disease. Juvenile Chinook salmon fed the 1× PBDE diet were more susceptible to L. anguillarum than salmon fed the control diet. This suggests that juvenile salmonids in the lower Willamette River exposed to PBDEs may be at greater risk for disease than nonexposed juvenile salmonids. In contrast, salmon that consumed the 10× PBDE diet were not more susceptible to the pathogen than salmon fed the control diet. The mechanisms for the dichotomous results observed in disease susceptibility between salmon fed the 1× and 10× PBDE diets are currently not known but have also been observed in other species exposed to PBDEs with respect to immune function.

Movements of Male California Sea Lions Captured in the Columbia River

Abstract There is growing concern in the Pacific Northwest over predation by migratory male California sea lions (Zalophus californianus) on threatened and endangered salmonid (Onchorynchus spp.) stocks. We compared movements of 14 male California sea lions known to have previously consumed salmonids at Bonneville Dam on the Columbia River or Willamette Falls on the Willamette River (“river”-types), with 12 animals of unknown foraging history (“unknown”-types). We captured sea lions in the Columbia River and instrumented them with satellite-linked transmitters during 2003–2004, 2004–2005, and 2006–2007. Transmitters operated for an average of 87.9 d (range 23-200 d) resulting in 14,539 location fixes. All 14 river-type animals returned to either Bonneville Dam or Willamette Falls whereas none of the 12 unknown-types exhibited this behavior. Minimum upstream and downstream transit times between the mouth of the Columbia River and Bonneville Dam (210 rkm) were 1.9 d and 1 d. Duration at the dam ranged from ...

“Let us honor those to whom honor is due”: The Discovery of the Final Link in the Southern Route to Oregon

 OHQ vol. 111, no. 2 “Let us honor those to whom honor is due”© 2010 Oregon Historical Society research files The Discovery of the Final Link in the Southern Route to Oregon by Stafford Hazelett The Southern Route to Oregon, the longest alternative route of the nineteenth-century overland emigrant trails, was established by a group of fifteen explorers who could easily have died because they had to travel long distances without water.1 One of the group’s leaders,Levi Scott,recalled one day of the journey: “The outlook was not at all promising that we should be able to reach water, again, in one day. Our course lay to the south across a vast sandy desert and this proved to be as hot a day as I ever experienced in my life. . . . We traveled until about 3 o’clock in the afternoon without any indication of water.”2 Despite such an unpromising outlook, they all managed to make it out of the desert and establish a new wagon road for emigrants , but how, exactly, they found their way from the barren Black Rock Desert to the life-giving Humboldt River has remained a mystery. Locating that path provides an important contribution to the ongoing work of documenting and understanding the experience of Euro-Americans migrating to the Oregon Country. Fur trappers and traders led missionaries to the Oregon Country during the 1830s, and then the missionaries sent letters home, recruiting people who came and built settlements around the missions. By 1842, emigrants had defined a route from Missouri to Oregon that allowed the passage of farm wagons loaded with families and their equipment for a new life, and they negotiated a route to California by 1844, with wagons passing down the Humboldt River to the Sierra Nevada. These overland routes were barely sufficient to support the lives of the emigrants and their draft animals. Water was often scarce and dangerous to drink. Grasses for feeding the animals were plentiful only during the first half of the trip and then were  Hazelett, The Final Link in the Southern Route to Oregon scattered and isolated for the second half, and there were difficult mountain ranges and dangerous rivers to cross. Many lives were lost. Children were especially vulnerable to injury, disease, and death. Explorers, many of whom had seen or heard of other routes, searched for safer ways for the emigrants to travel.3 Explorers concentrated most of their efforts on eliminating or reducing two great detours that kept emigrants from traveling a direct route to Oregon after crossing the South Pass, in what is now central Wyoming and about halfway between the jump-off point of Independence, Missouri, and the Willamette Valley destinaThis map shows the state of the overland emigrant trails to Oregon and California in 1848. The Applegate Cutoff (referred to in this article as the South Road or Southern Route) opened in 1846. The Lassen Trail opened off the Applegate Cutoff in 1848, not 1846, as shown here. South Pass is on the far right. Map from So Rugged and Mountainous, by Will Bagley. Copyright© 2010 by the University of Oklahoma Press, Norman. Reprinted by permission of the publisher. All rights reserved.  OHQ vol. 111, no. 2 tion. The first great detour led south to Fort Bridger and then north to Fort Hall.The Oregon Trail then went on a nearly direct route west to Fort Boise.The second great detour turned north from Fort Boise to the valley of the Columbia River. On reaching the Columbia, emigrants turned west, again,and proceeded to the north end of the Willamette River valley. Overland emigrants gathered information about the journey from three sources: they hired guides who had traveled the country, like Caleb Greenwood, James Clyman, and Moses “Black” Harris; they read reports of explorers such as Wilkes and Frémont; and they bought maps of the explorations. Mapmaker John Arrowsmith of London produced a series of continually improving maps of the Oregon Country from 1832 to 1844, basing them on the reports of PeterSkeneOgdenandotherHudson’s Bay Company explorers.4 American maps were based on the explorations of Capt. Charles Wilkes, leader of the U.S. Exploring...

Fish Use of Intermittent Watercourses Draining Agricultural Lands in the Upper Willamette River Valley, Oregon

AbstractHistorically, the upper Willamette River valley in western Oregon was characterized by seasonal floods and large expansions of its stream network. During the past century, human activities have altered or eliminated many intermittent stream and floodplain habitats in the valley. As a result, the remaining intermittent streams and ditches, referred to as watercourses, may still provide habitat that is critical for native fish. Our objectives were to determine (1) fish presence, (2) the spatial gradients of fish distribution (including species identity, native versus nonnative status, and numbers), (3) fish use of the intermittent streams as spawning and nursery habitats, and (4) the main factors that influence the numbers of fish and fish species. In the winter and spring of 2002–2003, we examined the distributions of fish species in five subbasins within the Willamette River valley. The sampling sites were in intermittent watercourses that drained grass seed–producing fields. We collected water samples and sampled fish from December to May with minnow traps and an electrofishing unit and collected data on the standard fish habitat variables at all sites in spring. Thirteen fish species were found and only three of them were exotic. The presence of recently hatched and juvenile fish shows that intermittent watercourses offer conditions suitable for spawning and juvenile rearing. The two watershed‐scale variables with the most influence on fish species richness were the percentage of the watershed covered by forest and the distance to perennial water, the first of which had a direct relationship to species diversity and the second an inverse relationship. In turn, fish abundance had a negative, albeit modest, relationship with the distance to perennial water. Among local‐scale variables, water velocity and conductivity were inversely related to species richness and fish numbers. Our results highlight the relevance of intermittent agricultural watercourses for native fish species in the Willamette River valley and call for the promotion of agricultural conservation practices that benefit farmers while maintaining aquatic biodiversity in floodplain habitats.

Polybrominated diphenyl ether flame retardants in eggs may reduce reproductive success of ospreys in Oregon and Washington, USA

Spatial and temporal assessments and reports of polybrominated diphenyl ether (PBDE) flame retardants in birds remain sparse. In the present study, PBDEs were detected in all 120 osprey (Pandion haliaetus) eggs collected. The eggs were collected from nests along the Columbia, Willamette and Yakima rivers of Oregon (OR) and Washington (WA) and in Puget Sound (WA) between 2002 and 2007. PBDE congeners: 17, 28, 47, 49, 66, 85, 99, 100, 138, 153, 154 (possible coelution with brominated biphenyl 153 [BB153]), 183, 190 (detected in one egg), 209 (not detected), and BB101 (only detected in 2006 and 2007) and total-alpha-hexabromocyclododecane (only detected in five eggs) were analyzed for in the egg samples. Eggs from reservoirs in the forested headwaters of the Willamette River (2002) contained the lowest concentrations of SigmaPBDEs (geometric mean [range], 98 [55.2-275] ng/g wet weight [ww]), while those from the middle Willamette River (2006) contained the highest (897 [507-1,880] ng/g ww). Concentrations in eggs from the Columbia River progressively increased downstream from Umatilla, OR (River Mile [RM] 286) to Skamokoa, WA (RM 29), which indicated additive PBDE sources along the river. In general, regardless of the year of egg collection, differences in PBDE concentrations reported in osprey eggs along the three major rivers studied (Columbia, Willamette and Yakima) seem to reflect differences in river flow (dilution effect) and the extent of human population and industry (source inputs) along the rivers. PBDE concentrations increased over time at two locations (Seattle, WA; Columbia River, RM 29-84) where temporal patterns could be evaluated. Only during 2006 (on the middle Willamette River, RM 61-157) and 2007 (on the lower Columbia River, RM 29-84) did SigmaPBDE concentrations in osprey eggs exceed 1,000 ng/g ww with negative relationships indicated at both locations between productivity and SigmaPBDE concentrations in eggs (P = 0.008, P = 0.057). Osprey eggs from Everett, WA contained nearly twice the SigmaPBDE concentration (geometric mean 239 vs. 141 ng/g ww, range 124-384 vs. 22.2-819 ng/g ww, P < or = 0.05) as double-crested cormorant (Phalacrocorax auritus) eggs collected at the same location and time, which is likely due to dietary differences. No significant relationship (all Ps > 0.147) was indicated between PBDE congeners (including SigmaPBDEs) and eggshell thickness at the concentrations observed in this study.

Potential Dispersal of the Non-Native Parasite Myxobolus cerebralis in the Willamette River Basin, Oregon: A Qualitative Analysis of Risk

Myxobolus cerebralis, the myxosporean parasite responsible for whirling disease in salmonids, was first detected in the United States in 1958. It has since spread across the country, causing severe declines in wild trout populations in the intermountain west. This study qualitatively assesses the risk of introduction and establishment of the pathogen into the Willamette River basin, Oregon, by examining potential routes of dissemination and relationships among obligate hosts, the parasite, and the environment. The approach is a synthesis of historical data, literature, and original research. The risk of M. cerebralis introduction in the Willamette River basin is addressed as a function of three main elements of dispersal: (1) movement of infected fish by humans, (2) natural dispersal (via migratory birds and stray anadromous salmonids), and (3) recreational activities. Establishment of the parasite is dependent upon several environmental and biological factors, including water temperatures, density, and spatial/temporal overlap of hosts, and the distribution and genetic composition of the oligochaete host, Tubifex tubifex. This study finds the probability of introduction of the parasite to vary throughout the Willamette River basin. Areas with greater probability have been identified as the Clackamas and Santiam River subbasins. If the pathogen were introduced, probability of establishment is high in certain areas of the basin as conditions are appropriate for propagation of the parasite lifecycle.

A long‐term, multitrophic level study to assess pulp and paper mill effluent effects on aquatic communities in four us receiving waters: Characteristics of the study streams, sample sites, mills, and mill effluents

Watershed characteristics, study streams, sample sites, mills, and mill effluents are provided for 4 streams included in a long-term study to assess potential effects of pulp and paper mill effluents on US receiving waters. The study streams are Codorus Creek (Pennsylvania, USA), Leaf River (Mississippi, USA) and McKenzie and Willamette rivers (Oregon, USA) and were chosen to represent a blend of mill process types, effluent concentrations, and coldwater/warmwater stream systems. The described effluent quality, water quality, and habitat data sets encompass the initial 7 to 8 y of a study anticipated to continue >10 y and provide a backdrop to a series of articles describing periphyton, macroinvertebrate, and fish community properties in these same streams. The mean in-stream waste concentration (IWC) for these 4 effluent discharges was 32.4%, 2.0%, 0.5%, and 0.2% v/v for Codorus Creek and Leaf, McKenzie, and Willamette rivers, respectively, as compared with a median of 0.4% for US mills. Effluent quality measurements included Selenastrum capricornutum, Ceriodaphnia dubia, and Pimephales promelas chronic bioassays as sanctioned by the US Environmental Protection Agency for estimating effluent effects on receiving-water aquatic communities. Based on mean bioassay inhibition concentration for a 25% effect and on mean IWC, a margin of safety against adverse biological effects of 2, 25, 137, and 150 times was indicated for Codorus Creek and Leaf, McKenzie, and Willamette rivers, respectively. Habitat and water quality assessment was carried out over a gradient of sample sites above and below the effluent discharge to determine nonmill-related conditions that might interfere with interpretation of effluent effects. Noneffluent related localized differences in conditions for some parameters, including current velocity (McKenzie River), and surface incident photosynthetically active radiation (Codorus Creek and Willamette River) occurred at the sample stations immediately upstream or downstream of the effluent discharge. In addition, broader watershed differences were evident on Codorus Creek, where a relatively rich riparian corridor and stream structure occurred upstream in contrast to areas of canopy and stream-structure loss in the downstream urban area. The mill effluent discharges contributed to increases in receiving-water color and conductivity, although upstream tributaries contributed additional conductivity to Codorus Creek and color to the Leaf River. The McKenzie River provided the only example of a nutrient increase immediately downstream of a mill discharge. This increase in total nitrogen (0.11 vs 0.16 mg/L) could not, however, be differentiated with respect to whether it was of mill effluent or tributary stream origin. Tributary streams were potentially important total nitrogen contributors on Codorus Creek and the Willamette River. As an integrated study, the effluent quality and physical/chemical watershed descriptions provided here represent 1 component of the broader study addressing potential point-source effluent effects within the context of the larger watershed and a multiyear timescale. The absence of effluent-related in-stream chemical/physical responses, other than increases in conductivity and color, and a considerable bioassay-based margin of safety, provides for a working hypothesis that there will be no effluent-related biological population/community responses from these 4 mill discharges. This hypothesis, as it relates to periphyton, macroinvertebrate, and fish communities, will be addressed in other articles in this series.

Spatial and temporal patterns of periphyton chlorophyll a related to pulp and paper mill discharges in four us receiving streams

Nutrients in pulp and paper mill effluent (PPME) have been implicated in increased periphyton chlorophyll a (chl a) downstream of discharges. These findings are largely based on short-term studies conducted in artificial stream channels or mesocosms and often in oligotrophic systems, and it is unclear if long-term chl a patterns in higher-nutrient systems would show similar response. We conducted a long-term study of 4 receiving waters (Codorus Creek, Pennsylvania; the Leaf River, Mississippi; and the McKenzie and Willamette rivers, Oregon) in which periphyton samples and associated data on water quality (nitrogen and phosphorus concentrations, pH, color, and conductivity) and 2 physical habitat variables (depth and current velocity) were collected over an 8-y period from multiple sites upstream and downstream of PPME discharges. Study streams represented different ecoregions, warm- and coldwater systems, gradients of in-stream effluent concentration (<1-33%), and mill process types. General Linear Models examining the main and interaction effects of site, season, and year on periphyton chl a for each of the 4 streams showed periphyton chl a downstream of the PPME discharge in Codorus Creek and the McKenzie River was greater at some, but not all upstream sites, suggesting these differences may be due to factors other than PPME. Mean periphyton chl a ranged from <1 to 285 mg/m2 across streams, with relatively consistent site patterns across seasons and years. Overall, chl a in the spring and summer was greater than in the fall in Codorus Creek and on sand substrates in the Leaf River, with overall differences across years seen on rare occasions in the Leaf and Willamette rivers. Regression models examining environmental-chl a relationships explained 45.4% and 30.2% of variation in periphyton chl a in the McKenzie River and Codorus Creek, respectively, and <10% in the Leaf and Willamette rivers. Physical variables (stream depth and current velocity) were the most important model variables in the McKenzie River, while total nitrogen and color were of greatest importance in Codorus Creek. The findings of this study demonstrate the inherent variability of chl a standing crops, highlight the complexity of lotic periphyton communities, and reiterate the importance of long-term, multi-season studies in elucidating spatial and temporal patterns.

Patterns of macroinvertebrate assemblages in a long‐term watershed‐scale study to address the effects of pulp and paper mill discharges in four us receiving streams

Changes in macroinvertebrate communities exposed to pulp and paper mill effluent (PPME) have been seen in mesocosm and short-term field studies. However, long-term patterns of macroinvertebrates in PPME receiving streams have not been examined. We conducted a study of 4 PPME receiving streams (Codorus Creek, PA; the Leaf River, MS; and the McKenzie and Willamette rivers, OR) over 9 y to assess temporal patterns in macroinvertebrate community structure and metrics related to PPME discharge. Study streams represented different ecoregions, warm-/cold-water systems, gradients of PPME concentration (<1%-33%), and mill process types. Bray-Curtis similarity and nonmetric multidimensional scaling showed significant community differences across sites in Codorus Creek, but differences were related to stream temperature patterns and not PPME. In the other study streams, seasonal community differences across years were greater than differences across sites. General linear models were used to examine spatial and temporal variation in macroinvertebrate metric response (% dominant taxa, density, richness, Hilsenhoff Biotic Index [HBI], Simpson's Index, and ash-free dry mass). Mean HBI scores indicated that the macroinvertebrate community reflected fair to very good water quality conditions, with water quality typically classified as "good" at most sites. Significant site differences in macroinvertebrate metric response were uncommon in the Leaf, McKenzie, and Willamette rivers but were seen in all metrics in Codorus Creek, where metric response was spatially variable. In the McKenzie River, there was an increase in mean HBI scores at sites downstream of the mill relative to 1 of the 2 upstream sites. However, significant differences were seen only between 1 upstream and downstream site, and HBI scores at all downstream sites consistently reflected "good" water quality. Significant annual differences in metric response were typical in all rivers. Water quality (pH, conductivity, total nitrogen) and habitat (velocity, depth, substrate composition) variables explained community structure patterns in the Leaf and McKenzie rivers, but macroinvertebrate-environment relationships were weak in the other 2 streams. The results of this study indicate that macroinvertebrate community structure is temporally variable and reiterate the importance of long-term studies for accurate determination of the effects of point sources such as PPME on receiving systems.

Patterns of fish community structure in a long‐term watershed‐scale study to address the aquatic ecosystem effects of pulp and paper mill discharges in four us receiving streams

Physiological changes have been seen in individual fish exposed to pulp and paper mill effluent (PPME), but it is unclear whether community-level changes are seen in fish in PPME receiving waters. We conducted a study of 4 PPME receiving streams (Codorus Creek, PA, USA), the Leaf River (Forrest and Perry Counties, MS, USA), and the McKenzie and Willamette rivers (Lane County, OR, USA) over 9 y to assess temporal patterns in the type and relative abundance of fish species and measures of community structure and function related to PPME discharge. We used boat and backpack electrofishing to sample large- and small-bodied fish from the McKenzie and Willamette rivers, boat electrofishing to sample large-bodied fish from the Leaf River, and backpack electrofishing to sample the entire fish community from Codorus Creek. Study streams represented different ecoregions, warm- and coldwater systems, gradients of PPME concentration (<1%-33%), and mill process types. Bray-Curtis similarity and nonmetric multidimensional scaling showed high variation in fish communities across sites, seasons, and years. Significant site differences in fish communities were seen in most streams and community types, but distinct separation of sites was seen only in Codorus Creek and unrelated to PPME discharge. No seasonal differences were seen in fish community structure in any stream, with only weak annual patterns in large-bodied fish in the Leaf River and small-bodied fish in the McKenzie River. General linear models were used to examine spatial and temporal variation in fish metric response (abundance, species richness, Simpson's diversity, % dominant species, standing crop, % DELT, % intolerant, % omnivore, % piscivore). Significant site differences in metric response were largely limited to Codorus Creek and unrelated to PPME. Significant reductions of % dominant taxa of small-bodied fish and % large-bodied piscivores were also observed downstream of the PPME discharge on the McKenzie River relative to upstream sites. Seasonal changes in fish metric response were rare, and changes with year were variable. The relationship between fish community structure and water quality variables (pH, color, conductivity, total phosphorus, total nitrogen) was weak in all streams for all community types. The results of this study show that PPME exposure has little effect on fish communities in these streams and aid in addressing management strategies. The high spatial and temporal variability reiterate the importance of long-term studies to elucidate patterns in receiving waters.

A long‐term, multitrophic level study to assess pulp and paper mill effluent effects on aquatic communities in four us receiving waters: Background and status

An industry-funded, long-term, receiving water study was initiated in 1998/1999 to adress questions about the potential effects of pulp and paper mill effluent discharges on US receiving waters. Although the study continues, the knowledge gained to date provides an opportunity to reflect on the study development process, its progress, and its outcomes. As a backdrop to a series of articles in this special issue describing study results, this article describes the process by which study information objectives were identified as well as the process by which the experimental design was developed. A review of past literature and research identified gaps in long-term population/community data about effluent effects and that, consequently, emerged as a primary information objective. The selected streams for study included 1) Codorus Creek (Pennsylvania, USA), 2) Leaf River (Mississippi, USA), 3) McKenzie River (Oregon, USA), and 4) Willamette River (Oregon) represent a blend of mill process types, coldwater and warmwater stream types, and a range of effluent concentrations. Measurements included numbers of periphyton, macroinvertebrate, and fish communities; the assessment of water and effluent quality; laboratory bioassays; and fish full-life-cycle assays. Information objectives included addressing natural variability and, consequently, the study included long-term temporal (>10 y) and watershed-scale spatial frameworks. Regional-scale ecological risk assessments were performed for each site that aided in placing each site in an ecological and regulatory context. An adaptive-management process is described that allowed for modifications over time as a result of lessons learned as the study progressed. Results from the initial 7 to 8 y of monitoring, as described in the series of articles in this special issue, provide a unique data set with respect to addressing point-source pulp and paper mill effluent discharge concerns and may serve as a template for others to use in developing monitoring or management programs to assess or address water quality conditions or concerns.

A long‐term, multitrophic level study to assess pulp and paper mill effluent effects on aquatic communities in four us receiving waters: Lessons learned

Lessons learned from the development, implementation, and initial 8 y of study findings from a long-term study to assess the effects of pulp and paper mill effluents on receiving waters are summarized as a conclusion to a series of articles (this issue) on study findings. The study, based on industry-defined information needs, was developed via a science-based experimental design into a long-term (>10 y) watershed-scale monitoring program that integrated in-stream population/ community assessment, laboratory chronic bioassays, and fathead minnow full life-cycle assays as well as water quality and effluent quality monitoring and habitat assessment in addressing the presence of effluent effects. The 4 study streams (Codorus Creek, PA; Leaf River, MS; and the McKenzie and Willamette rivers, OR) represented both bleached and unbleached kraft mill processes and effluent concentrations that ranged from near typical for the United States (0.4%) to very high (Codorus Creek= 32%). Following 8 y of monitoring, the weight of evidence suggests an absence of biological differences at stations downstream of the mill discharges for periphyton or macroinvertebrates and, with the exception of 1 of 9 large-bodied fish and 1 of 7 small-bodied fish community structure metrics for 1 river (McKenzie), an absence of differences for fish communities. Laboratory bioassay and fathead minnow full-life cycle tests supported a substantial "margin of safety" in that, depending on the effluent, adverse responses did not occur until effluent concentrations were from 2 times to more than 150 times in-stream concentrations. The incorporation of a watershed spatial scale illustrated that each sample site tended to be unique over the 28 to 50 km monitored segments with respect to habitat and that knowledge of these variables permitted accurate evaluations of effluent effects. Similarly, the multiyear study framework provided information regarding the natural seasonal and year-to-year variability in fish communities and consequently a better understanding of how potential effluent effects signals could be expressed within this variability. The study incorporated an adaptive management strategy that provided for study design and monitoring modifications over time as a way of benefiting from practical experience and knowledge gained through time and to optimize the use of study resources. Results from this initial 8 y of monitoring, to our knowledge, represent the longest-known population/community-level assessment of the in-stream effects of pulp and paper mill effluents. Beyond the lessons learned with respect to effluent effects are those related to the esign and conduct of long-term watershed-scale studies that may be of use to others in developing watershed assessment or management programs.

Responses of fathead minnows (pimephales promelas) during life‐cycle exposures to pulp mill effluents at four long‐term receiving water study sites

We exposed fathead minnows (Pimephales promelas to 7 concentrations of effluents from pulp mills at 4 Long-Term Receiving Water Study (LTRWS) sites. The primary objective of these investigations was to determine the potential for toxicity, particularly on fish reproduction, of the pulp mill effluents using laboratory tests. These tests were performed as LTRWS fish community assessments were being completed, thus results of the laboratory fish reproduction tests could be compared to in-stream fish community measurements. In general, bioindicators measured during the life-cycle tests, including gonadosomatic index (GSI), hepatosomatic index, condition factor, numbers of tubercles on heads of males and females, and gonadal histology did not show consistent patterns or dose response and did not predict effects on egg production. Gonadosomatic indexes and tubercles also did not indicate estrogenic or androgenic responses to the effluents during the life-cycle tests. The most consistently sensitive test endpoint showing a dose response was the 25% inhibition concentration (IC25) for egg production. Based on this endpoint all 4 effluents had effects on fish reproduction from 8% by volume to 100% effluent. However, in-stream effects on fish reproduction would not be expected based on these 4 life-cycle tests for any of the LTRWS stream sites. The mean effluent concentration in Codorus Creek, Pennsylvania, USA was approximately 32%, and the IC25 for the life-cycle test was 100% effluent, providing a margin of safety of approximately 3 times. The margins of safety at the other sites are much greater: 34 times for Leaf River, Mississippi, USA (IC25 = 69%, 2% mean receiving water concentration), 36 times for the McKenzie River, Oregon, USA (IC25 = 18%, 0.5% mean receiving water concentration), and 40 times for the Willamette River, Oregon, USA (IC25 = 8%, 0.20% mean receiving water concentration). Effects on fish numbers, diversity, and community structure due to the effluent were also not found during the LTRWS, which is consistent with these laboratory results. These findings indicate that in this case, when laboratory results combined with in-stream effluent concentrations suggest in-stream effects on fish population are not expected, the laboratory results are consistent with the in-stream observations. However, inferences about situations where laboratory results predict in-stream effects cannot be made from these data.

Genetic Stock Composition of Subyearling Chinook Salmon in Seasonal Floodplain Wetlands of the Lower Willamette River, Oregon

AbstractWe used genetic identification methods to examine the stock composition of subyearling Chinook salmon Oncorhynchus tshawytscha in floodplain wetland and main‐stem habitats of the lower Willamette River, Oregon. Using a microsatellite DNA baseline of 13 standardized loci and 30 Columbia River basin populations, we analyzed 280 subyearlings collected in winter and spring 2005‐2006 from wetland and main‐stem river sites. Genetic stock identification analysis indicated that spring Chinook salmon originating from the Willamette River made up a substantial proportion of the samples and contributed 16‐71% to sample mixtures representing the wetland habitat sites. Fall Chinook salmon from lower Columbia River sources were also present and contributed 58% of winter samples. Spring Chinook salmon from lower Columbia River populations were present in both wetland (17%) and river (16%) samples in spring 2005, and subyearlings from summer‐fall‐run populations in the middle and upper Columbia River contributed to spring wetland samples in 2006 (26%). The results suggest that floodplain restoration projects intended to improve fish habitats during winter and spring periods in the lower Willamette River may benefit Chinook salmon populations from the upper Willamette River, lower Columbia River, and upper Columbia River summer‐fall evolutionarily significant units.

Alternate spore stages of Myxobilatus gasterostei, a myxosporean parasite of three-spined sticklebacks (Gasterosteus aculeatus) and oligochaetes (Nais communis)

Two spore stages in the life cycle of Myxobilatus gasterostei, a ubiquitous myxosporean parasite of three-spined sticklebacks, were identified by matching small subunit ribosomal RNA gene sequences of actinospores from a worm with myxospores from fish. A Nais communis oligochaete collected in the Willamette River, Oregon, USA was found to produce a triactinomyxon-type actinospore which was distinguishable from previous records by its large size (approximately 500 microm across) and number of germ cells (approximately 500). Its small subunit ribosomal RNA gene sequence was >99% similar to M. gasterostei from Europe. Two of ten sticklebacks from the Willamette had renal infections with Myxobilatus myxospores which were smaller than the type description of M. gasterostei Parisi (1912) but were consistent with subsequent records. Primer Mg1097r was designed to selectively amplify M. gasterostei in the presence of another common kidney myxosporean, Sphaerospora elegans. DNA sequences of spores from the fish were identical to each other and were 99.8% similar over 2,112 nt to the spores from the oligochaete. The 0.2% sequence divergence comprised polymorphisms at five loci, which suggested that multiple alleles were present in the parasite population. This is the first Myxobilatus species shown to have two spore stages in its life cycle and to infect an invertebrate. The infected oligochaete underwent paratomic fission to produce two daughter worms with parasite stages in their intestinal epithelia, which suggested that M. gasterostei may be sustained and dispersed within the invertebrate host population.

Spatial and Temporal Variation of Freely Dissolved Polycyclic Aromatic Hydrocarbons in an Urban River Undergoing Superfund Remediation

Urban rivers with a history of industrial use can exhibit spatial and temporal variations in contaminant concentrations that may significantly affect risk evaluations and even the assessment of remediation efforts. Concentrations of 15 biologically available priority pollutant polycyclic aromatic hydrocarbons (PAHs) were measured over five years along 18.5 miles of the lower Willamette River using passive sampling devices and HPLC. The study area includes the Portland Harbor Superfund megasite with several PAH sources including remediation operations for coal tar at RM 6.3 west and an additional Superfund site, McCormick and Baxter, at RM 7 east consisting largely of creosote contamination. Study results show that organoclay capping at the McCormick and Baxter Superfund Site reduced PAHs from a precap average of 440 +/- 422 ng/L to 8 +/- 3 ng/L postcapping. Results also reveal that dredging of submerged coal tar nearly tripled nearby freely dissolved PAH concentrations. For apportioning sources, fluoranthene/pyrene and phenanthrene/anthracene diagnostic ratios from passive sampling devices were established for creosote and coal tar contamination and compared to published sediment values.

PCDDs, PCDFs, PCBs, OC pesticides and mercury in fish and osprey eggs from Willamette River, Oregon (1993, 2001 and 2006) with calculated biomagnification factors

The osprey (Pandion haliaetus) population nesting along the main stem Willamette River and lower Santiam River was first studied to evaluate contaminants and reproductive rates in 1993 when 78 occupied nests were present. By 2001, the population increased to 234 occupied nests, a 13.7% annual rate of population increase. A sample egg was collected from each of a series of nests along the Upper River (river mile 55-187) in 1993, 2001 and 2006 to evaluate trends of persistent contaminants (organochlorine [OC] pesticides, polychlorinated biphenyls [PCBs], polychlorinated dibenzo-p-dioxins [PCDDs], and polychlorinated dibenzofurans [PCDFs]). Nearly all OC pesticide residues decreased significantly, e.g., p, p'-DDE (DDE) from 2,350 to 1,353 to 210 microg/kg wet weight (ww). PCBs followed a similar pattern over time, e.g., SigmaPCBs 688 to 245 to 182 microg/kg ww, while PCDDs and PCDFs showed a more precipitous decline (often 85-95%) between 1993 and 2001, with no egg analyses warranted in 2006. During 2001-2002, sample osprey eggs were also collected from nests at three Headwater Reservoirs and two lower reaches (Newberg Pool and Tidal Portland) of the Willamette River, as well as the lower portion of the Santiam River to evaluate spatial residue patterns. Significant differences were seldom detected among the different sampling areas for OC pesticides (probably due to small sample sizes), although higher concentrations were often seen in the lower reaches, e.g., DDE 901 microg/kg ww (Headwater Reservoirs), 1,353 (Upper River), 1,384 (Newberg Pool) and 2,676 (Tidal Portland). PCB congener concentrations in eggs were usually higher in the Tidal Portland reach than at other locations and often significantly higher than at the Headwater Reservoirs or Upper River. Mercury (first analyzed in eggs in 2001), PCDDs and PCDFs were extremely low in 2001/2002 with no significant spatial patterns. Whole fish composite samples of largescale sucker (Catastomus macrocheilus) and northern pikeminnow (Ptychocheilus oregonensis), which account for about 90% of the biomass in the diet of this osprey population, were also collected from the Willamette River in 1993 and 2001 and analyzed for the same contaminants as osprey eggs. Contaminant residues in fish from the Upper River decreased between 1993 and 2001, paralleling findings for osprey eggs. Likewise, spatial patterns for fish residues paralleled findings for osprey eggs from the different reaches in 2001. A second empirical estimate of biomagnification factors (BMFs) from fish to osprey eggs for OC pesticides, PCBs, PCDDs and PCDFs (ww and lipid weight [lw] basis) was calculated based on residue data collected in 2001. The two independent BMF estimates (1993 and 2001) for each contaminant from the Upper River provide a measure of consistency, e.g., DDE (ww) 87 and 79, (lw) 103 and 112; SigmaPCBs (ww) 11 and 8.4, (lw) 13 and 12. Mercury did not biomagnify from fish to osprey eggs (BMF = 0.60). Legacy contaminants investigated had limited (perhaps only DDE), if any, effects on reproductive success of the increasing osprey population nesting along the Willamette River by 2001.

Discussion of “Evolution of the Continuous Truss Bridge” by Francis E. Griggs Jr.

As fans of truss bridges in general and of Gustav Lindenthal in particular, we commend the author for his comprehensive review of design, construction, and use of continuous truss bridges in the United States. We are pleased to have the opportunity to add his paper to our library of bridge history and engineering. To supplement the author’s effort, we respectfully offer information on what appears to be a generally overlooked milestone in continuous truss design and construction: the Sellwood Bridge in Portland, Oregon, a four-span continuous truss highway bridge designed by Lindenthal and still in use. Figs. 1 and 2 are recent photos of the bridge. To our knowledge, the four-span continuous figuration is exceedingly rare, if not unique. Also notable is the fact that the Sellwood Bridge opened for traffic in 1925, well before the 1929 Lake Champlain Bridge cited by the author as the first long-span continuous bridge built for highway traffic. Lindenthal himself acknowledged the four-span continuous configuration of the Sellwood truss spans in a 1929 letter to the editor of Engineering News Record as follows: “I believe also that I was the first engineer in this country to use continuous girders on a large scale, in the Sciotoville Bridge. Since then, the Steubenville bridge over the Ohio River, with three spans, was built for the Pennsylvania Railroad; I suggested the continuous system for this bridge and made the check calculations. Only recently I completed two city bridges of the continuous girder type over the Willamette River in Portland, Ore., one of three spans Ross Island Bridge , another of four spans Sellwood . G. Lindenthal, Consulting Engineer, New York City” Lindenthal 1929 The Sellwood Bridge is a two-lane structure over the Willamette River at the south edge of Portland. It now carries about 30,000 vehicles per day, the heaviest-traveled two-lane bridge in Oregon. The approach spans are reinforced concrete, and the main spans are four continuous subdivided Warren-type deck trusses with span lengths of 246, 300, 300, and 246 ft, respectively. Five concrete piers support the truss spans, with one pier founded on timber piles and four on spread footings. As-built drawings indicate that two other piers were designed with piles, but the piles apparently were deleted during construction. The truss spans are supported by a fixed bearing at the center pier and by expansion bearings at the other four piers. Gustav Lindenthal designed the Sellwood Bridge for Multnomah County which includes Portland as part of a multibridge program in the mid-1920s. The county commissioners brought

TCE plume remediation via ISCR‐enhanced bioremediation utilizing EHC® and KB‐1®

AbstractGroundwater below an operating manufacturing facility in Portland, Oregon, was impacted by chlorinated volatile organic compounds (CVOCs), with concentrations indicative of a dense, nonaqueous‐phase liquid (DNAPL) release. The downgradient plume stretched under the adjacent Willamette River, intersecting zones of legacy impacts from a former manufactured gas plant (MGP). An evaluation of source‐area and downgradient plume treatment remedies identified in situ bioremediation as most likely to be effective for the CVOC plume, while leaving the legacy impacts for other responsible parties. With multiple commercially available products to choose from, the team developed and implemented a bench test to identify the most appropriate technology, which was further evaluated in a field pilot study. The results of the testing demonstrated conclusively that bioremediation enhanced by in situ chemical reduction (ISCR) using EHC® and KB‐1® was most appropriate for this site, providing outstanding results. The following describes the implementation and results of the tests. © 2008 Wiley Periodicals, Inc.

Anticipating floodplain trajectories: a comparison of two alternative futures approaches

Scenario-based investigations explore alternative future courses of action in a widening array of situations. Anticipating landscape patterns and the values behind them are recurring needs in such investigations. While it is accepted that how scenario assumptions are framed and who frames them matters, the sensitivity of resulting trajectories to contrasting scenario framing and modeling processes is rarely tested. Using comparable scenarios we contrast landscape change trajectories produced from two distinct approaches to modeling scenario assumptions: the first uses lay citizen groups and deterministic land allocation modeling, the second uses experts from biophysical and social sciences and agent-based modeling. Scenarios are defined and mapped for the year 2050 in western Oregon’s Willamette River Basin along a gradient of conservation oriented to development-oriented assumptions using first citizen-based and then expert-based approaches. The landscape variability and trajectories for the citizen-based Conservation 2050 and Development 2050 scenarios are then characterized and compared with those of the expert-based Conservation 2050 and Development 2050 scenarios. Results distinguish areas where trajectories always vary regardless of approach or scenario from those that never vary. Policy influence on trajectory is illustrated using agent-based model results where land conversion serves purposes of wealth production and ecosystem function. Results depict areas with strong coupling between policy and trajectory as those places experiencing the same pattern of change over time regardless of scenario. Results also indicate that the greater the variability of a given scenario’s trajectories, the more successful the scenario is at avoiding scarcity of wealth and ecosystem function.