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James D. Yager, PhD
Johns Hopkins University

Introduction to Risk Assessment
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Organization of this Lecture
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Section A: introduction to risk assessment and elements of the risk assessment process
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Section B: toxicity assessment (testing)
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Section C: in vivo tests or bioassays
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Section D: in vitro tests: genotoxicity
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Section E: in vitro tests: cellular toxicity
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Dose-response relationships
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Application of testing and dose-response to risk assessment
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“Hazardous to my Health”
“Another day—another chance something will be found hazardous to my health.”
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The Toxicological Paradigm
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National Geographic: October, 2006
Source: David Ewing Duncan. (October, 2006). “The Pollution Within.” National Geographic.
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U.S. Agencies for Toxic Chemical Regulation
Agency Legislation
FDA
EPA
Federal Food, Drug, and Cosmetic Act
Federal Insecticide, Fungicide, and
Rodenticide Act; Clean Air Act; Safe
Drinking Water Act and 1996 Amendment;
Food Qual. Protection Act 1996; Toxic
Substances Control Act; Superfund
Amendments and Reauthorization
OSHA Occupational Safety and Health Act;
CPSC
DOT
Federal Hazardous Substance Act
Consumer Product Safety Act
Hazardous Materials Transportation Act
Covers
Drugs; food additives; food contact substance; coloring
(no carcinogens)
Air and water pollutants; contaminated sites; environmental estrogens/endocrine disruptors; pesticides; toxic substances
Occupational exposure
Consumer products
Shipping hazardous materials
Source: adapted by CTLT from: NRC/NAS, Toxicity Testing for Assessment of Environmental Agents, 2006
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What Is Risk Assessment?
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Risk assessment is a characterization of the probability of potentially adverse health effects from human exposures to environmental hazards
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Risk Assessment Process
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Risk Assessment Process
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Risk Assessment Process
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Exposure assessment (what, who, how, extent)
What exposure(s) were/are/anticipated to occur?
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Chemicals/agents
Who is exposed? Identify exposed populations
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Age (adults, children, elderly), gender, lifestyle, genetic susceptibilities
How: identify routes of exposure
Extent: estimate degree of exposure
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What, Who, How, Extent
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