Otoliths are frequently used to infer environmental conditions or fish life history events based on trace-element concentrations. However, otoliths can be comprised of any one or combination of the ...three most common polymorphs of calcium carbonate-aragonite, calcite, and vaterite-which can affect the ecological interpretation of otolith trace-element results. Previous studies have reported heterogeneous calcium carbonate compositions between left and right otoliths but did not provide quantitative assessments of polymorph abundances. In this study, neutron diffraction and Raman spectroscopy were used to identify and quantify mineralogical compositions of Chinook salmon Oncorhynchus tshawytscha otolith pairs. We found mineralogical compositions frequently differed between otoliths in a pair and accurate calcium carbonate polymorph identification was rarely possible by visual inspection alone. The prevalence of multiple polymorphs in otoliths is not well-understood, and future research should focus on identifying otolith compositions and investigate how variations in mineralogy affect trace-element incorporation and potentially bias environmental interpretations.
Injury and mortality of fish during downstream passage through hydropower turbines is among the leading direct impacts of hydropower. Understanding the relationships among various strike variables ...and injury and mortality rates are necessary for improvements in turbine design. We subjected three species of fish to simulated blade strike in laboratory studies with different blade thicknesses, impact velocities, and body orientations to develop relationships between these variables and probability of injury and mortality. Midbody strikes resulted in higher mortality than head strikes, and tail strikes produced the least mortality. Lateral strikes caused more mortality than dorsal and ventral strikes, and higher strike velocities and thinner blades contributed to increased mortality. Several injury types were significantly associated with increased mortality, including injuries to the operculum, gills, viscera, heart, liver, swim bladder, muscle, and bone fractures. Results from this study will be used to define biologically based design criteria that can be used by turbine designers to improve designs (e.g., increased leading-edge thickness and slower turbine speeds) to minimize the probability and impact of blade strike.
The fish and plant communities in a pond contaminated with polychlorinated biphenyls (PCBs) in East Tennessee, USA, were manipulated to reduce ecological and human-health risk associated with ...exposure to the chemical contaminants. We evaluated the success of the remedial action using a habitat valuation approach, as well as measuring PCB concentrations in fish. Risk reduction objectives included: alter the fish community to favor fish that do not resuspend, bioaccumulate, or biomagnify PCBs; stabilize contaminated sediments to improve water quality; and stabilize shoreline soils and enhance riparian habitat. Fish targeted for removal included gizzard shad, largemouth bass, and nonnative carp. Reduced PCB concentrations in fish have characterized the new bluegill-dominated community, although a weir-overtopping event led to the need for additional removals of gizzard shad and largemouth bass. Sunfish abundance is high, as was intended. Moreover, amphibian and waterbird diversities have increased in the years following biomanipulation, possibly owing to improvements in the riparian zone and increased structural (vegetation) complexity in both the aquatic and terrestrial environment. Thus, the remedial action has improved aspects of habitat value, and PCB concentrations in sunfish have dropped below the remediation level (risk-based target value) for this pond (1 µg/g in fish fillets or 2.3 µg/g in whole body fish).
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This paper addresses an uncommon but effective option for remediation of environmental contaminants in aquatic environments, biomanipulation. PCBs have important implications for human health and ecosystems. The paper combines analyses of PCB concentrations, habitat valuation, and water quality metrics, following biomanipulation of a pond. The 10-year study is longer than most published studies of environmental contaminants. The relevance is confirmed through funding from the US Department of Energy’s Environmental Management program, and federal and state regulatory agencies have shown interest in the findings. Biomanipulation is a less expensive and effective remediation alternative, compared to excavation of chemical contaminants.
This paper addresses an uncommon but effective option for remediation of environmental contaminants in aquatic environments, biomanipulation. PCBs have important implications for human health and ecosystems. The paper combines analyses of PCB concentrations, habitat valuation, and water quality metrics, following biomanipulation of a pond. The 10-year study is longer than most published studies of environmental contaminants. The relevance is confirmed through funding from the US Department of Energy’s Environmental Management program, and federal and state regulatory agencies have shown interest in the findings. Biomanipulation is a less expensive and effective remediation alternative, compared to excavation of chemical contaminants.
•An ecological manipulation in a contaminated pond reduced PCB concentrations in fish.•Habitat value metrics were measured over a 15-y period.•The pond transitioned from gizzard shad and largemouth bass dominance to sunfish.•PCB concentrations in bluegill decreased below risk-based targets.•Habitat metrics for most taxa are at least equal to those before biomanipulation.
The effect of coal ash exposure on fish health in freshwater communities is largely unknown. Given the large number of possible pathways of effects (e.g., toxicological effect of exposure to multiple ...metals, physical effects from ash exposure, and food web effects), measurement of only a few health metrics is not likely to give a complete picture. The authors measured a suite of 20 health metrics from 1100+ fish collected from 5 sites (3 affected and 2 reference) near a coal ash spill in east Tennessee over a 4.5‐yr period. The metrics represented a wide range of physiological and energetic responses and were evaluated simultaneously using 2 multivariate techniques. Results from both hierarchical clustering and canonical discriminant analyses suggested that for most species × season combinations, the suite of fish health indicators varied more among years than between spill and reference sites within a year. In a few cases, spill sites from early years in the investigation stood alone or clustered together separate from reference sites and later year spill sites. Outlier groups of fish with relatively unique health profiles were most often from spill sites, suggesting that some response to the ash exposure may have occurred. Results from the 2 multivariate methods suggest that any change in the health status of fish at the spill sites was small and appears to have diminished since the first 2 to 3 yr after the spill. Environ Toxicol Chem 2014;33:1903–1913. Published 2014 Wiley Periodicals, Inc. This article is a US Government work and, as such, is in the public domain in the United States of America.
Human activities can be powerful drivers of ecosystem change within catchments. While most long‐term catchment studies have been conducted at pristine sites, such studies are less common from sites ...more impacted by human activity. The Oak Ridge National Laboratory's Biological Monitoring and Abatement Program (BMAP) was developed in the mid‐1980s to (1) assess compliance with environmental regulations, (2) identify causes of adverse ecological impacts, (3) provide data for human and ecological risk assessments, and (4) evaluate the effectiveness of remedial actions taken to mitigate the impacts of contaminants in soils, groundwater, and surface water by documenting ecological recovery on the Oak Ridge Reservation (ORR), a federally owned 33 476‐acre site in eastern Tennessee, managed by the US Department of Energy. The ORR is composed of multiple watersheds containing many small to mid‐size streams. BMAP uses an integrated approach for determining stream health; its databases include long‐term seasonal records of contaminant concentrations in water and biota, data from aquatic toxicity testing, and surveys of macroinvertebrate and fish assemblages from impacted and reference streams. These long‐term data provide valuable records of degradation and recovery in catchment ecosystems. Our objective here is to describe our study system and data series in order to increase awareness of the availability of these long‐term data to the catchment science community.
The Oak Ridge Reservation (ORR) is a federally owned site in eastern Tennessee, USA, managed by the U.S. Department of Energy with a long history of impacts from human activities. We present long‐term data for determining stream health in multiple watersheds on the ORR, including long‐term seasonal records of contaminant concentrations in water and biota, data from aquatic toxicity testing, and surveys of macroinvertebrate and fish assemblages from impacted and reference streams.
On December 22, 2008 a dike containing coal fly ash from the Tennessee Valley Authority Kingston Fossil Plant near Kingston Tennessee USA failed and resulted in the largest coal ash spill in U.S. ...history. Coal ash, a by-product of coal combustion, is known to contain multiple contaminants of concern, including arsenic and selenium. The purpose of this study was to investigate species differences in the bioaccumulation of arsenic and selenium and potential factors contributing to these differences (i.e., trophic dynamics and gut pH) in the vicinity of the Kingston coal ash spill. Elevated levels of arsenic and selenium were observed in various tissues of largemouth bass, white crappie, bluegill and redear sunfish from sites associated with the Kingston coal ash spill. Highest concentrations of selenium were found in redear sunfish with liver concentrations as high as 24.83mg/kg dry weight and ovary concentrations up to 10.40mg/kg dry weight at coal ash-associated sites. Investigations into the gut pH and trophic dynamics of redear sunfish and bluegill demonstrated a large difference in the gut physiology between these two species. Redear sunfish stomach and intestinal pH was found to be 1.1 and 0.16 pH units higher than in bluegill, respectively. In addition, fish from coal ash-associated sites showed enrichment differences (15N and 13C) compared to no ash sites, indicating differences in food web dynamics between sites. These results imply the incorporation of coal ash-associated compounds into local food webs and/or a shift in diet at ash sites compared to the no ash reference sites. Based on these results, further investigation into a broader food web at ash-associated sites is warranted.
► Environmental investigation of the largest coal ash spill in US history. ► Selenium and arsenic bioaccumulation is elevated in fish at coal ash-associated sites. ► Trophic dynamics (stable isotopes C and N) are shifted at coal ash-associated sites. ► Physiological differences in the gut of redear sunfish and bluegill exist. ► Potential evidence of coal ash constituents being incorporated into the food chain.
A 4.1 million m
3
coal ash release into the Emory and Clinch rivers in December 2008 at the Tennessee Valley Authority’s Kingston Fossil Plant in east Tennessee, USA, prompted a long-term, ...large-scale biological monitoring effort to determine if there are chronic effects of this spill on resident biota. Because of the magnitude of the ash spill and the potential for exposure to coal ash-associated contaminants e.g., selenium (Se), arsenic (As), and mercury (Hg) which are bioaccumulative and may present human and ecological risks, an integrative, bioindicator approach was used. Three species of fish were monitored—bluegill (
Lepomis macrochirus
), redear sunfish (
L. microlophus
), and largemouth bass (
Micropterus salmoides
)—at ash-affected and reference sites annually for 5 years following the spill. On the same individual fish, contaminant burdens were measured in various tissues, blood chemistry parameters as metrics of fish health, and various condition and reproduction indices. A multivariate statistical approach was then used to evaluate relationships between contaminant bioaccumulation and fish metrics to assess the chronic, sub-lethal effects of exposure to the complex mixture of coal ash-associated contaminants at and around the ash spill site. This study suggests that while fish tissue concentrations of some ash-associated contaminants are elevated at the spill site, there was no consistent evidence of compromised fish health linked with the spill. Further, although relationships between elevated fillet burdens of ash-associated contaminants and some fish metrics were found, these relationships were not indicative of exposure to coal ash or spill sites. The present study adds to the weight of evidence from prior studies suggesting that fish populations have not incurred significant biological effects from spilled ash at this site: findings that are relevant to the current national discussions on the safe disposal of coal ash waste.
Passage of fishes through hydropower turbines and water pumping stations may cause mortal injury as the result of exposure to blade strike impact. Laboratory trials of simulated blade strike on two ...morphologically distinct fishes, American eel (
Anguilla rostrata
) and bluegill sunfish (
Lepomis macrochirus
) were undertaken to assess injury and mortality rates. We hypothesized that bluegill would have comparable rates of injury and mortality to other laterally compressed fishes while anguilliform American eel would be more resistant to injury. American eel had low observed mortality rates at the highest velocity tested (13.6 m/s), but many fish were observed with vertebral fractures which we categorized as functionally dead individuals. Bluegill were more susceptible to blade strike with high rates of mortality regardless of blade thickness, velocity, or impact conditions (location, angle, or fish orientation). These data have broadened our understanding of the range of responses among entrained fishes exposed to blade strike and represent species with low (American eel) and high (bluegill) susceptibility to injury and mortality. Our blade strike data can help inform safer turbine designs or prioritization of pumps that minimize traumatic injury and mortality of fishes during non-volitional passage through hydropower turbines or water pumping stations.
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