Grantee Research Project Results
2004 Progress Report: Development and Evaluation of Chemical Indicators for Monitoring Ecological Risk
EPA Grant Number: R828675C005Subproject: this is subproject number 005 , established and managed by the Center Director under grant R828675
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Center for Air, Climate, and Energy Solutions
Center Director: Robinson, Allen
Title: Development and Evaluation of Chemical Indicators for Monitoring Ecological Risk
Investigators: Swackhamer, Deborah L. , Mount, David , Ankley, Gary , Burkhard, Lawrence , Simcik, Matthew , Cook, Philip , Erickson, Russell , Diamond, Steven
Current Investigators: Swackhamer, Deborah L. , Simcik, Matthew , Mount, David , Ankley, Gary , Cook, Philip , Diamond, Steven , Erickson, Russell , Burkhard, Lawrence
Institution: University of Minnesota , U. S. Environmental Protection Agency
EPA Project Officer: Packard, Benjamin H
Project Period: January 10, 2001 through January 9, 2005 (Extended to January 9, 2006)
Project Period Covered by this Report: January 10, 2003 through January 9, 2004
RFA: Environmental Indicators in the Estuarine Environment Research Program (2000) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Water , Aquatic Ecosystems
Objective:
The overall goal of this research project is to identify and validate effective contaminant indicators of adverse impacts on estuarine ecosystem health. Indicators will be developed in the Great Lakes but also will be applicable to both marine and freshwater ecosystems. These contaminant indicators will be used to evaluate ecological condition. The specific goal of this research project is the evaluation of two indicators:
- indicator polycyclic aromatic hydrocarbons (PAHs) of photo-induced toxicity to fish and benthic organisms;
- and organic chemical indicators of xenoestrogenic exposure to fishes.
The assessment of ecological condition in an effective manner is best accomplished using integrative indicators of condition. These indicators should be cost-effective and applicable across multiple scales as well as provide useful information for environmental managers. This subproject focuses on contaminant indicators that will provide a measure of the condition of the estuarine ecosystem. These indicators also will serve as diagnostic indicators that will identify the primary stressors affecting the specific ecological endpoint of concern. We have focused on PAH compounds and environmental estrogens because they are widespread in the environment, have existing sources, and are of current concern.
The specific hypotheses we are testing are:
- specific PAHs in combination with UV penetration are indicators of potential loss of vulnerable species within coastal fish and/or benthic communities;
- and specific chemicals are indicators of endocrine disruption in fish via the estrogen receptor.
Data collected to test these hypotheses will be used to demonstrate the degree of usefulness of these two groups of indicator compounds as diagnostic indicators for estuarine ecosystems.
For both indicators, we will compare contaminant concentrations to a biological endpoint or condition across a gradient of non-degraded to highly degraded sites in approximately 20 locations being studied by the other indicator project groups in the program. For the PAH photo-induced toxicity indicator, we will collect the necessary field data to test the model developed in the laboratory by the collaborators at U.S. Environmental Protection Agency Mid-Continent Ecology Division (EPA-MED) (Diamond, Mount, Erickson). These data include the concentrations of PAHs in sediment, larval fish, and oligochaetes (to determine the bioaccumulation factors and to provide the doses for the model); sediment photo-induced toxicity potential (assayed in the laboratory using the aquatic annelid Lumbriculus [laboratory test organism] and field sediments); and UV dose (obtained from field measurements). The toxicity that is predicted from the model will be compared to that measured in the laboratory assay. Results will be used to calibrate the model, and independent field data will be used to validate the model. Although photo-induced toxicity has been extensively studied and its acute toxicity demonstrated in the laboratory, this will be the first field test of such an indicator.
The xenoestrogen indicators will be identified in an analogous manner. A suite of potential xenoestrogens will be measured in fish tissue, sediment, and/or water and compared to vitellogenin (Vtg) induction in wild and caged male fish (a bioindicator of individual estrogen exposure) at the same gradient of sites. Using correlative statistical techniques, we will identify specific indicator xenoestrogens that are associated with vitellogenin induction. This would represent the first link of vitellogenin induction and chemical exposure in field sites other than near sewage treatment plants.
Progress Summary:
PAH Phototoxicity
Photo-induced toxicity of PAHs to larval fish is a function of exposure to both PAHs and ultraviolet-A (UV-A) light. During Year 4 of the project we performed work to determine PAH exposure at our field sites, on develop a model for UV-A exposure, and refine the indicator model through controlled laboratory experiments.
UV-A exposure depends on factors such as light intensity, dissolved organic carbon, and total suspended solids. We have developed a model for measuring UV-A attenuation in the water column of the coastal Great Lakes. This model involves the measurement of spectral attenuation using a spectrophotometer, a simple piece of equipment common to most laboratories, and suspended particulate matter. Because of the ease of the measurements and incorporation of the influence of suspended particulate matter on attenuation, we have created a useful tool for managers of the coastal Great Lakes. Our method can be used to evaluate the UV-A exposure setting at other sites around the Great Lakes and, more importantly, predict how changes in suspended particulate matter might affect UV-A attenuation. For instance, the introduction of zebra mussels have dramatically reduced the amount of suspended particulate matter in the coastal areas and, therefore, may have a commensurate increase in UV-A exposure to larval fish in those areas. A manuscript of our UV-A model results has been prepared and is currently undergoing internal review for submission to the Journal of Great Lakes Research. This paper is the basis for Andy Adams’ M.S. thesis, which he will defend in the coming months. Andy will continue his Ph.D., working on the PAH exposure and phototoxicity modeling portions of the project.
PAH exposure is a function of partitioning from the sediments to the water column and into larval fish. This process is described as a bio-sediment accumulation factor (BSAF). To describe BSAFs at our sites, we have analyzed sediments, oligochaete worms placed in the sediments, and larval fish collected in the field for a suite of PAHs. These sample analyses are completed, and the QA/QC review of the data is underway, to be followed by determination and interpretation of the BSAFs.
Once we elucidate PAH and UV-A exposure, they will be incorporated into a paper describing the phototoxic potential at each site. Results of our UV-A model have been presented at two scientific conferences this past year, and the bio-sediment accumulation work will be presented at this spring’s International Association for Great Lakes Research Conference.
During the past year, EPA-MED staff completed additional field experiments examining the response of the zooplankter Daphnia magna to ambient exposures of PAHs and sunlight in a contaminated embayment in the St. Louis River estuary. Photo-activated toxicity was measurable but less dramatic than in the previous field season, which corresponded to lower ambient PAH concentrations in the water column. These data provide important linkages between field exposures and expected biological response, as well as between responses measured in the laboratory and field, and assist in finalizing the indicator.
Controlled exposures to a single PAH and laboratory-generated UV continued. The list of test species was expanded to include yellow perch, an important species in all of the Great Lakes. Yellow perch embryos were exposed to UV and pyrene in the laboratory to develop exposure response relationships that can be extrapolated to field conditions. Field measurements of ambient UV also were made at locations where yellow perch were spawning in local, inland lakes. Also in the field, collections were made of zooplankters inhabiting the upper water column in local lakes during mid-day in an effort to identify species at highest risk for UV/PAH exposure. Finally, laboratory exposures using D. magna were expanded to include longer exposure durations (21-day) and reproduction as an endpoint to determine what extent of chronic effects of UV/PAH exposure may be important.
Environmental Estrogens (EEs)
The efforts on this indicator during Year 4 of the project were spent on an assessment of why this indicator failed to be transferred from the laboratory to the field and conducting some additional experiments to further bound the utility of some of the tools available for assessing estrogenicity. A series of three manuscripts were written that addressed the above issues as part of the Ph.D. dissertation of Randy Lehr, who has worked on this project since its inception.
The first manuscript provided a comprehensive review and critical assessment of the tools that have been developed to assess estrogenic exposures and response in fish, from the measurement of chemical concentrations in fish tissue all the way to the proteomic and genomic measurements that indicate a response at the cellular or molecular level. To establish exposure-effect relationships, researchers have identified a number of measurement endpoints that characterize signal transduction at a number of intermediary steps throughout the estrogen response pathway. Development of these assays, however, has not followed a standardized approach, and different measurement endpoints have been quantified using different analytical techniques and exposure scenarios. As a result, the sensitivity and diagnostic and predictive potential for these assay systems is different. In general, assays that characterize estrogen signal transduction at lower levels of biological organization are the most amenable to high throughput and diagnostic analysis but the poorest predictors of potential effects at individual and population levels. Conversely, assays that characterize estrogen signal transduction at higher levels of biological organization are the best predictors of potential effects but the least amenable to high throughput, diagnostic analysis. This complicates the linkage of exposure and effect using a single endpoint and requires the analysis of multiple endpoints to mechanistically link exposure and effect. This approach is recommended but is not amenable to adopt as a monitoring approach for the end-users of this project. At the beginning of this project, the complexity of the estrogen response pathway was not fully appreciated, nor were these tools fully developed.
One of the more promising assessment tools we hoped to utilize was measuring response of vitellogenin mRNA induction in fathead minnows placed in cages at sites around the Great Lakes. There are different versions of this assay developed by different investigators, however, and the sensitivity of the assay varies considerably, influencing the utility and interpretation. So we conducted an experiment to determine some of the factors that might influence the differences observed in the assays. Research has demonstrated that the sensitivity of Vtg endpoints is affected by a variety of different assay parameters, but one parameter that has not yet been thoroughly evaluated is the use of different carrier solvents. To examine the effects of carrier solvent selection on the Vtg mRNA endpoint, we exposed male fathead minnows (Pimephales promelas) to two different doses (10 and 100 ng/L) of 17 α-ethinylestradiol across four different carrier solvent types, water (H2O), dimethyl sulfoxide (DMSO), ethanol (EtOH), and triethylene glycol (TEG) using a 48-hr static exposure. Among the carrier solvent treatments, the Vtg mRNA response was highest in the H2O and EtOH and lowest in the DMSO and TEG treatment groups. Results suggest that use of the DMSO and TEG carrier solvents (at a concentration of 50 µL/L) creates a more uniform 17 α-ethinylestradiol exposure, but suppresses the magnitude of the Vtg mRNA response. In addition, the data suggest that use of a saturation-based solution to generate carrier solvent-free aqueous exposures may be confounded by estrogenic impurities in analytical standards.
The final manuscript in the dissertation is directed at providing advice to environmental managers who wish to monitor for EEs. Management of chemical contaminants is highly dependent upon the establishment of exposure-effect relationships. Establishment of exposure-effect relationships for EEs is complicated by a variety of factors and, as such, the management of EEs presents a variety of challenges. To aid the management process, researchers have developed a variety of assays to establish exposure-effect relationships, and each of these assays is likely to be best suited for different aspects of the management process. Assays that quantify exposure and effect at higher levels of biological organization integrate EE exposure and are likely to be more appropriate for assessment of ecosystem condition and long-term monitoring. Assays that assess exposure and effect at lower levels of biological organization are more mechanistically diagnostic and thus likely to be more appropriate for the identification of specific chemicals of concern and design of management interventions. The unique physical-chemical and toxicological properties of EEs also affect the design of management plans and the ability to communicate management results.
In summary, the complexity of the estrogen response pathway necessitates having indicators that can both assess exposure, and assess an integrated measure of the response elicited as a result of that exposure. The tools available do not do both of these well, and a monitoring program requires the use of multiple tools to assess exposure as well as assess specific and integrated responses to provide the link of exposure and effect. Furthermore, tools are needed to bridge the assessment of individuals to populations and communities. These tools are in the research and development phase, and few have been used effectively to assess effects of EEs to fish populations in the field.
Future Activities:
The investigator(s) did not report any future activities.
Journal Articles:
No journal articles submitted with this report: View all 22 publications for this subprojectSupplemental Keywords:
PAHs, photo-induced toxicity, xenoestrogenic compound, fishes, endocrine disruption, larval fish, vitellogenin induction, Lumbriculus, environmental estrogen, environmental indicators, coastal wetlands, Great Lakes, ecological indicators, monitoring, water, stress, aquatic ecosystem, water quality,, RFA, Scientific Discipline, ENVIRONMENTAL MANAGEMENT, Geographic Area, ECOSYSTEMS, Ecosystem Protection/Environmental Exposure & Risk, Ecosystem/Assessment/Indicators, Ecosystem Protection, exploratory research environmental biology, Monitoring/Modeling, Ecological Effects - Environmental Exposure & Risk, Ecological Monitoring, Environmental Monitoring, Ecological Risk Assessment, Ecology and Ecosystems, Great Lakes, Ecological Indicators, Risk Assessment, coastal ecosystem, anthropogenic stress, ecological condition, biodiversity, environmental measurement, ecosystem assessment, coastal environments, PAH, analytical chemistry, estuarine ecoindicator, ecological assessment, xenoestrogen indicators, ecosystem indicators, aquatic ecosystems, ecological risk, environmental stress, environmental estrogens, water quality, fish models, ecological models, land useRelevant Websites:
Progress and Final Reports:
Original AbstractMain Center Abstract and Reports:
R828675 Center for Air, Climate, and Energy Solutions Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R828675C001 Great Lakes Diatom and Water Quality Indicators
R828675C002 Vegetative Indicators of Condition, Integrity, and Sustainability of Great Lakes Coastal Wetlands
R828675C003 Testing Indicators of Coastal Ecosystem Integrity Using Fish and Macroinvertebrates
R828675C004 Development and Assessment of Environmental Indicators Based on Birds and Amphibians in the Great Lakes Basin
R828675C005 Development and Evaluation of Chemical Indicators for Monitoring Ecological Risk
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.
Project Research Results
Main Center: R828675
279 publications for this center
58 journal articles for this center