Part 1b Part 1b NATURE OF THE ENVIRONMENT AND POPULATIONS; BASIC CONCEPTS OF EXPOSURE, DOSE AND RISK

Overview of Presentation  Definition of ‘environment’  Nature of hazardous environmental agents: chemical, biological, and physical  Dispersal of chemical and biological agents  Human populations at risk  Pathways and routes of exposure  Exposure & dose concepts  Exposure-response (dose-outcome) relationships  Risk assessment

environment exposure people dose response outcome control defense ? HAZARD

DEFINITION OF ‘ENVIRONMENT’ Ambient versus personal –ambient (via air, water, workplace, etc.) over which the individual has little control –personal (diet, smoking, personal habits, etc.) over which individual has, within psychosocial constraints, significant control

EHS OR.. Chemical, physical and biological –as it relates to chemical and biological agents (in air, water, food, etc.) that can enter the body by inhalation, ingestion or dermally. –as it relates to physical agents (noise, vibration, light, heat, etc.) that can damage vulnerable tissue.

... OR... Behavioral environment –behavioral/psychophysical/cult ural aspects which influence how we interact with our physical environment - these therefore become part of the overall environment.

... OR... Socioeconomic environment –the reality that people of lower socioeconomic status exhibit greater morbidity and mortality. –issues of geography, income, education, etc. –issues of ‘social justice’.

THE BIG PICTURE The ecosystem The biosphere The food chain Energy cycles

POLLUTANTS Unwanted chemicals in the environment, characterized by the potential to cause harm to humans and other living organisms.

EHS 507 The Continuum From Emission of a Contaminant (adverse agent) to a Health Effect (Lioy, P. Env. Sci. Tech. 24, 7, 1990, ) Transport and transformation Contaminant source emissions Accumulation in environment Human contact: exposure Potential dose to body Early expression of disease Health Effect Biologically effective dose Internal dose

EHS 507 The Continuum From Emission of a Contaminant (adverse agent) to a Health Effect Transport and transformation Contaminant source emissions Accumulation in environment Human contact: exposure Potential dose to body Early expression of disease Health Effect Biologically effective dose Internal dose

EHS 507 Type, origin and exposure setting of agents physical agents biological agents chemical agents natural synthetic community occupational Type of agent Origin of agent Setting for exposure to agent particulate, radon, EMF e. coli in drinking water, airborne fungal spores NO 2 from vehicle emissions, lead from a smelter arsenic in groundwater SO 2 from combustion of sulfur containing fuels ambient air pollution benzene exposure in shoe factory glue Examples