EOH 2504 Lecture 3 Exposure Assessment and Dose DefinedWhere Does Expose Assessment Fit Into the Risk Assessment Paradigm?Occupational/Environmental Exposure DefinitionExposure AssessmentLioy et al., Journal of Exposure Analysis and Environmental Epidemiology (2005) 15, 463. Differences Between Exposure and DoseComponents of Environmental and Occupational Health Exposure PathwaysFactors Influencing Human ExposurePrimary Routes of Human Environmental ExposureImportant TermsImportant Terms ContinuedUpcoming Presentation AssignmentsEOH 2504Lecture 3Exposure Assessment and Dose DefinedConrad Daniel Volz, DrPH, MPHAssistant Professor, Environmental and Occupational Health, University of Pittsburgh, Graduate School of Public Health http://www.pitt.edu/~cdv5/; Director-Center for Healthy Environments and Communities http://www.chec.pitt.edu; Director, Environmental Health Risk Assessment Certificate Program http://www.publichealth.pitt.edu/interior.php?pageID=82Conrad Daniel Volz, DrPH, MPHAssistant Professor, Environmental and Occupational Health, University of Pittsburgh, Graduate School of Public Health http://www.pitt.edu/~cdv5/; Director-Center for Healthy Environments and Communities http://www.chec.pitt.edu; Director, Environmental Health Risk Assessment Certificate Program http://www.publichealth.pitt.edu/interior.php?pageID=82Where Does Expose Assessment Fit Into the Risk Assessment Paradigm?• Step 1 Hazard Identification (Toxicology and Epidemiology)• Step 2, Dose-Response Assessment (Generally Toxicology and Environmental Epidemiology)• Step 3, Exposure Assessment (Exposure Assessment Scientists- Assessors)• Step 4, Risk Characterization (Risk Assessors)• Step 5, Risk CommunicationOccupational/Environmental Exposure Definition• Exposure is defined as contact over time and space between a-person and one or more biological, chemical or physical agents (USNRC, 1991a).-an ecological receptor and one or more biological, chemical or physical agents.Exposure Assessment• Combines elements of industrial hygiene, health physics, epidemiology and relies on aspects of toxicology, biostatistics, atmospheric sciences, geology, analytical chemistry, food sciences, physiology, and environmental modeling.• Describes the nature and size of various populations exposed to an agent and the magnitude and duration of the exposure.• Determine the degree of contact that a person has with an agent and estimate the magnitude of the absorbed dose.Lioy et al., Journal of Exposure Analysis and Environmental Epidemiology (2005) 15, 463.• An Exposure is defined as the event when a person comes into contact with a toxic material. Coming into contact with a toxic material is a highly dynamic process that varies from person to person (depending on behavior, location, and life style) and from one toxic substance to another.• The goal of Exposure Science is to identify and characterize ‘real world’ contacts with and uptake in the body of toxic materials that can cause acute or chronic health effects.Differences Between Exposure and Dose• The term exposure refers to the concentration of an agent at the boundary between an individual and the environment as well as the duration of contact between the two, but dose refers to the amount actually deposited or absorbed in the body over a given time period (Hatch and Thomas, Measurement Issues in Environmental Epidemiology).Exposure and Biomarkers of Exposure, Leading to DiseasePersonalized Exposure Assessment: Promising Approaches for Human Environmental Health Research Environmental Health Perspectives • VOLUME 113 | NUMBER 7 | July 2005.Components of Environmental and Occupational Health Exposure Pathways• Source (s)—Often with unique fingerprint(s).• Rate(s) of contaminant emissions.• Transport route(s) through environmental media.• Route(s) of exposure.• Exposure concentration(s).Factors Influencing Human Exposure• The duration, frequency and intensity of contact with the contaminant.How Long/Often and Much?• Identification of individual activity patterns, population distributions and susceptible populations.Primary Routes of Human Environmental Exposure• Dust, mist, fume, gas and/or vapor inhalation.• Dermal contact with contaminated soils or dusts or contaminated water.• Ingestion of contaminated food, water dusts and/or soil.Important Terms• Agent(s) -biological, chemical, physical, single agent, multiple agents, mixtures• Source(s)- anthropogenic/non-anthropogenic, area/point, stationary/mobile, indoor/outdoor• Transport/carrier medium- air, water, soil, dust, food, product/item• Exposure pathways(s)- eating contaminated food, breathing contaminated workplace or ambient air, touching residential/municipal surfaces or bathing in contaminated water.Important Terms Continued• Exposure concentration- mg/kg (food), mg/litre (water), μg/m3 (air), μg/cm2 contaminated surface), fibres/m3 (air), percent by weight or ppm (mg/kg) for contaminated soils.• Exposure route(s) -inhalation, dermal contact, ingestion, multiple routes.• Exposure duration- seconds, minutes, hours, days, weeks, months, years, lifetime, population-generational.• Exposure frequency- continuous, intermittent, cyclic, random, rare.• Exposure setting(s) -occupational/non-occupational (environmental), residential/non-residential, indoors/outdoors, recreational/non-recreational.• Exposed population- general population, population subgroups, individuals.• Geographic scope- site/source specific, local, regional, national, international, global.• Time frame- past, present, future, trends.Upcoming Presentation Assignments• Approaches to Environmental Exposure Assessment in Children, Virginia M. Weaver, Timothy J. Buckley, and John D.Groopman, Department of Environmental Health Sciences, Johns Hopkins University School of Hygiene and Public Health, Baltimore, Maryland, Environmental Health Perspectives * Vol 106, Supplement 3 June 1998.• Personalized Exposure Assessment: Promising Approaches for Human Environmental Health Research, Weis et alin VOLUME 113, NUMBER 7, July 2005, Environmental Health Perspectives.• FROM A THEORETICAL FRAMEWORK OF HUMAN EXPOSURE AND DOSE ASSESSMENT TO COMPUTATIONAL SYSTEM IMPLEMENTATION: THE MODELING ENVIRONMENT FOR TOTAL RISK STUDIES (MENTOR), Panos G. Georgopoulos, Paul J. Lioy in Journal of Toxicology and Environmental Health, Part B, 9:457–483, 2006.• Exposure Assessment