Grantee Research Project Results

Final Report: Reproduction of Birds and mammals in a terrestrial-aquatic interface

EPA Grant Number: R825433C008
Subproject: this is subproject number 008 , established and managed by the Center Director under grant R825433
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: UC Davis Center for Children's Environmental Health and Disease Prevention
Center Director: Van de Water, Judith
Title: Reproduction of Birds and mammals in a terrestrial-aquatic interface
Investigators: Lasley, Bill L. , Fry, D. Michael , Wilson, Barry W.
Institution: University of California - Davis
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 1996 through September 30, 2000
RFA: Exploratory Environmental Research Centers (1992) RFA Text |  Recipients Lists
Research Category: Center for Ecological Health Research , Targeted Research

Objective:

Numerous reports indicate that wildlife species are negatively impacted by environmental hazards. The most visible types of adverse effects on wildlife are associated with reproduction and development, but these adverse effects are not replicated when controlled exposures are investigated with laboratory animal models. The most likely reason for this discrepancy is that environmental hazards have species, gender, and life-stage specificities, and rodent models are not appropriate for understanding the mechanisms of toxic action in nonmurine species.

The objective of this research project was to develop methods to monitor wildlife species, and to employ nonmurine species in controlled laboratory experiments. Biomarker assays using urine and/or fecal samples have provided a means to monitor reproductive health in a wide range of free-ranging species; thus, we employed these methods to investigate the adverse effects of environmental hazards on elk, sheep, bison, sparrows, quail, chickens, and primates (including humans). This noninvasive approach has permitted the intense surveillance of free-ranging subjects before and during natural exposures, and it employs the same methods that can be used in controlled laboratory experiments. Using this strategy and dioxin as a model compound, we have shown an apparent universal interaction of dioxin with estrogen across a wide range of animal species. Despite this uniformity, dioxin exposure resulted in widely different adverse effects in different species and genders. Because estrogen is seasonally produced in many species, it is likely that dioxin also will have season-specific effects, although this was not examined directly. More important, the investigations in this project suggest that developmental defects resulting from arylhydrocarbon receptor exposure may be downstream of alterations in lipid metabolism. Taken together, the results of this program provide protocols and methods for investigating the adverse effects of environmental hazards on free-ranging wildlife, and demonstrate that even similar toxicants can have disparate effects in different species.

Summary/Accomplishments (Outputs/Outcomes):

The following activities were accomplished:

• We have shown that there are important similarities between the mechanisms that mediate the physiologic actions of sex steroid hormones and those that mediate the toxic actions of chlorinated hydrocarbons in mammals. Specifically, our data demonstrate that halogenated aromatic hydrocarbons (HAHs) act through some of the same cytosolic signal transduction pathways and/or gene activators as sex steroid hormones and growth factors. However, the xenobiotics may not require direct interaction with the hormone/growth factor receptors, but may interfere with downstream signals. This interpretation provides the first explanation of the cellular basis for species- and gender-specific differences in the severity of adverse effects resulting from exposures to environmental toxicants in vertebrate species.

• Our data indicate that toxicants that leak into the environment can cause illness and even death to many organisms. Toxicants are known to have varying impacts on an organism, depending on the organism’s species, gender, and age. Some toxicants interact with hormones, impact only certain organs in certain species, or have a greater or lesser impact depending on the season. The exact mechanisms by which toxicants have these specific effects are poorly understood. We have demonstrated that exposures that may not reveal toxic effects in laboratory animals may be responsible for severe adverse effects in wildlife species. This information will help environmental management agencies set limits for levels of toxicants in the environment.

• We have developed noninvasive, noncapture methods for monitoring the impact of toxicants on the reproductive health of wild birds and mammals. In most cases, these noninvasive methods involve the collection and analysis of the excreta, that is, feces or urine. We developed our methods by initially using domestic species as surrogates for the wildlife we wish to study in the field. We will use this method to examine the adverse effects of agrochemicals on immature and mature male and female chickens as surrogates for wild birds. Other researchers also may find this nonintrusive method useful for assessing the impact of toxics on wildlife.

• This study confirms gender-specific adverse effects of some environmental hazards in both mammals and birds, and links sex steroids to similar mechanism(s) of toxic action. Unlike mammals, however, female birds are more sensitive to dioxin-like compounds, and estrogen-treated males exhibit an enhanced adverse effect to 2,3,7,8-tetrachlorodibenzo-p-dioxin. Although the interactions of estrogen and polyaromatic hydrocarbons appear to be a common finding, the nature of these interactions is species specific. These results indicate that the development of toxic equivalent factors, which can be applied broadly to wildlife species, will require attention to both species- and gender-specific qualities of the organisms for which they are intended.

• The adverse effects of dioxin (an HAH) or chlorinated hydrocarbons vary among different avian species. We selected dioxin as the model compound for two reasons. First, it belongs to a family of compounds that are frequent contaminants of pesticides and other materials used in agriculture. Second, dioxin is the most potent of these compounds and produces the greatest effects, which are the easiest to study. Many studies using dioxin have been conducted in several laboratories, including our own. The current studies focus on combining dioxin with estrogen treatments because dioxins are thought to be endocrine disruptors and to antagonize the action of estrogens. Preliminary data indicate that the differences seen in the adverse effects of dioxin are related to differences observed in the cellular functions (such as signal transduction within a cell and gene activation), and that the interaction of estrogen with dioxin varies among species. Knowing that reactions vary among species will influence how researchers set up experimental controls in future studies.

Supplemental Keywords:

ecosystem, ecosystem protection, environmental exposure and risk, geographic area, international cooperation, water, terrestrial ecosystems, aquatic ecosystem, aquatic ecosystem restoration, aquatic ecosystems and estuarine research, biochemistry, ecological effects, ecological indicators, ecological monitoring, ecology and ecosystems, environmental chemistry, restoration, state, water and watershed, watershed, watershed development, watershed land use, watershed management, watershed modeling, watershed restoration, watershed sustainability, agricultural watershed, exploratory research environmental biology, California, CA, Clear Lake, Lake Tahoe, anthropogenic effects, aquatic habitat, biogeochemical cycling, ecological assessment, ecology assessment models, ecosystem monitoring, ecosystem response, ecosystem stress, environmental stress, environmental stress indicators, fish habitat, hydrologic modeling, hydrology, integrated watershed model, lake ecosystems, lakes, land use, nutrient dynamics, nutrient flux, water management options, water quality, wetlands., RFA, Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, INTERNATIONAL COOPERATION, Water, ECOSYSTEMS, Aquatic Ecosystem, Restoration, Aquatic Ecosystems & Estuarine Research, Ecological Indicators, Terrestrial Ecosystems, Aquatic Ecosystem Restoration, Watersheds, Environmental Chemistry, Ecosystem/Assessment/Indicators, Ecological Monitoring, Ecological Effects - Environmental Exposure & Risk, Biochemistry, Water & Watershed, Ecology and Ecosystems, Environmental Monitoring, nutrient flux, nutrient dynamics, watershed management, lake ecosysyems, water management options, lakes, water quality, watershed land use, watershed modeling, watershed restoration, agricultural watersheds, ecological assessment, wildlife habitat, terrestrial-aqautic interface, anthropogenic effects, fish habitat, hydrology, environmental stress, integrated watershed model, wetlands, ecosystem monitoring, ecosystem response, ecosystem stress, land use, hydrologic modeling, ecology assessment models, environmental stress indicators, watershed development, aquatic ecosystems, biogeochemcial cycling, reproductive health, aquatic habitat, agricultural watershed, watershed, watershed sustainablility

Relevant Websites:

http://ice.ucdavis.edu/cehr/ Exit

Progress and Final Reports:

Original Abstract

1997

1998

1999

Main Center Abstract and Reports:

R825433    UC Davis Center for Children's Environmental Health and Disease Prevention

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R825433C001 Potential for Long-Term Degradation of Wetland Water Quality Due to Natural Discharge of Polluted Groundwater
R825433C002 Sacramento River Watershed
R825433C003 Endocrine Disruption in Fish and Birds
R825433C004 Biomarkers of Exposure and Deleterious Effect: A Laboratory and Field Investigation
R825433C005 Fish Developmental Toxicity/Recruitment
R825433C006 Resolving Multiple Stressors by Biochemical Indicator Patterns and their Linkages to Adverse Effects on Benthic Invertebrate Patterns
R825433C007 Environmental Chemistry of Bioavailability in Sediments and Water Column
R825433C008 Reproduction of Birds and mammals in a terrestrial-aquatic interface
R825433C009 Modeling Ecosystems Under Combined Stress
R825433C010 Mercury Uptake by Fish
R825433C011 Clear Lake Watershed
R825433C012 The Role of Fishes as Transporters of Mercury
R825433C013 Wetlands Restoration
R825433C014 Wildlife Bioaccumulation and Effects
R825433C015 Microbiology of Mercury Methylation in Sediments
R825433C016 Hg and Fe Biogeochemistry
R825433C017 Water Motions and Material Transport
R825433C018 Economic Impacts of Multiple Stresses
R825433C019 The History of Anthropogenic Effects
R825433C020 Wetland Restoration
R825433C021 Sierra Nevada Watershed Project
R825433C022 Regional Transport of Air Pollutants and Exposure of Sierra Nevada Forests to Ozone
R825433C023 Biomarkers of Ozone Damage to Sierra Nevada Vegetation
R825433C024 Effects of Air Pollution on Water Quality: Emission of MTBE and Other Pollutants From Motorized Watercraft
R825433C025 Regional Movement of Toxics
R825433C026 Effect of Photochemical Reactions in Fog Drops and Aerosol Particles on the Fate of Atmospheric Chemicals in the Central Valley
R825433C027 Source Load Modeling for Sediment in Mountainous Watersheds
R825433C028 Stress of Increased Sediment Loading on Lake and Stream Function
R825433C029 Watershed Response to Natural and Anthropogenic Stress: Lake Tahoe Nutrient Budget
R825433C030 Mercury Distribution and Cycling in Sierra Nevada Waterbodies
R825433C031 Pre-contact Forest Structure
R825433C032 Identification and distribution of pest complexes in relation to late seral/old growth forest structure in the Lake Tahoe watershed
R825433C033 Subalpine Marsh Plant Communities as Early Indicators of Ecosystem Stress
R825433C034 Regional Hydrogeology and Contaminant Transport in a Sierra Nevada Ecosystem
R825433C035 Border Rivers Watershed
R825433C036 Toxicity Studies
R825433C037 Watershed Assessment
R825433C038 Microbiological Processes in Sediments
R825433C039 Analytical and Biomarkers Core
R825433C040 Organic Analysis
R825433C041 Inorganic Analysis
R825433C042 Immunoassay and Serum Markers
R825433C043 Sensitive Biomarkers to Detect Biochemical Changes Indicating Multiple Stresses Including Chemically Induced Stresses
R825433C044 Molecular, Cellular and Animal Biomarkers of Exposure and Effect
R825433C045 Microbial Community Assays
R825433C046 Cumulative and Integrative Biochemical Indicators
R825433C047 Mercury and Iron Biogeochemistry
R825433C048 Transport and Fate Core
R825433C049 Role of Hydrogeologic Processes in Alpine Ecosystem Health
R825433C050 Regional Hydrologic Modeling With Emphasis on Watershed-Scale Environmental Stresses
R825433C051 Development of Pollutant Fate and Transport Models for Use in Terrestrial Ecosystem Exposure Assessment
R825433C052 Pesticide Transport in Subsurface and Surface Water Systems
R825433C053 Currents in Clear Lake
R825433C054 Data Integration and Decision Support Core
R825433C055 Spatial Patterns and Biodiversity
R825433C056 Modeling Transport in Aquatic Systems
R825433C057 Spatial and Temporal Trends in Water Quality
R825433C058 Time Series Analysis and Modeling Ecological Risk
R825433C059 WWW/Outreach
R825433C060 Economic Effects of Multiple Stresses
R825433C061 Effects of Nutrients on Algal Growth
R825433C062 Nutrient Loading
R825433C063 Subalpine Wetlands as Early Indicators of Ecosystem Stress
R825433C064 Chlorinated Hydrocarbons
R825433C065 Sierra Ozone Studies
R825433C066 Assessment of Multiple Stresses on Soil Microbial Communities
R825433C067 Terrestrial - Agriculture
R825433C069 Molecular Epidemiology Core
R825433C070 Serum Markers of Environmental Stress
R825433C071 Development of Sensitive Biomarkers Based on Chemically Induced Changes in Expressions of Oncogenes
R825433C072 Molecular Monitoring of Microbial Populations
R825433C073 Aquatic - Rivers and Estuaries
R825433C074 Border Rivers - Toxicity Studies