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Wildlife Toxicology. Earliest type of environmental toxicology (Silent Spring hatched many new environmentalists --> public most interested in wildlife toxicology
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Earliest type of environmental toxicology (Silent Spring hatched many new environmentalists --> public most interested in wildlife toxicology Probably area of most true ecotoxicology - much of other environmental toxicology pays "lip service" to ecological mechanisms but wildlife toxicology often needs good knowledge of such mechanisms Arose from wildlife ecology instead of biomedical toxicology like most environmental toxicology Introduction
Introduction (con’t) • Much work based on putting out "fires“ • e.g Lake DeGray eagle die-off • Newest fire in Arkansas: external abnormalities in songbirds associated with Delta agricultural fields • Craighead, Mississippi and Poinsett counties • Normal abnormality rate = 0.5% • Delta farm field abnormality rate 7-9%
I. Basic concepts Def. - Assessment of chemical hazards in the environment to wildlife populations A. Major foci 1. Assessing causes and mechanisms of problems in the field (dousing the fire) 2. Predicting potential adverse affects through experiments and testing. Note: both above use laboratoy and field testing 3. Analytical chemistry - i.d. what is present and might be causing effect
Basic concepts (con’t) B. Exposure vs. Effect 1. Demonstrating exposure may be hard - tissue need to be sampled for "right stuff” 2. " effect of exposure is harder¯ (ex. PCBs detectable in all of us. Effect?) 3. Cause/effect or dose/response rare in unplanned wildlife contamination a. mostly infer from indirect evidence b. graded response in wildlife with changes in distance from source of contamination)
II. Special Considerations in Wildlife Toxicology A. Definition of wildlife varies
B. Species response varies in 1. Habitat requirements 2. Activity patterns (when to apply pesticides --> bluegill vs. bass) 3. Food habits (food chain considerations) 4. Detoxification mechanisms 5. Absorption pathways 6. Life stage sensitivities etc, etc.
C. Varied sources of stressors 1. Agrochemicals 2. Spent lead shot 3. Industrial waste 4. Acid precipitation 5. Irrigation 6. Mining 7. Logging
Summary • Wildlife toxicology is actually the single largest problem dealt with by environmental toxicology • Lots being done, but a lot less than on standard test orgs (some changing --> switching from Japanese quail to Bobwhite quail)