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					Environmental Health
Pollution

 Pollutants are emitted from natural and
  anthropogenic activities.
 Species have evolved tolerances in
  response to pollutants, however, when
  a species with a low tolerance
  encounters elevated concentrations of
  pollutants their population drops or
  even dies away.
  Terminology

 Pollution: introduces harmful materials or
  produces harmful conditions to the environment
  - introduced through
  a) Point Sources:
  b) Area Sources:
  c) Mobile Sources:
 Contamination: making something unfit for a
  particular use through the introduction of
  undesirable material.
Terminology

Toxicology: the science that studies chemicals
  that should be toxic
Carcinogen: a type of toxin that increases the
  risk of cancer
Synergism: the interaction of different
  substances resulting in a total effect greater
  than the sum of the effects of the separate
  sources
Measuring Pollutants

          depends on the substance
 Measuring
 Common Units
  – ppm: Parts per million
  – ppb: Parts per billion
  – Micrograms per cubicle meter (measures
    air)
Categories of Pollutants
 Infectious Agents
 Toxic Heavy Metals Organic Compounds
 Radiation
 Thermal Pollution
 Particulates
 Asbestos
 Electromagnetic Fields
 Noise Pollution
 Voluntary Exposure
Environmental Health

   BUTTERFLY MODEL for an Ecosystem Context.

                                              Elements
              Elements                        Home
              Air, Water                      Workplace
           Soil, Microbes                     Health Care
           Plants, Animals                    Neighborhoods
                                              Political Institutions

         Biophysical                          Socioeconomic
         Environment         Biological and   Environment
                             Behavioral
               Features      Filters          Features
              Air Quality                     Early Childhood
             Food Quality                     Development
             Water Quality                    Social Support
                                              Empowerment
                                              Community
Organism Response to Pollution

 Reactions are highly variable.
 Differences due to body size, age,
  general health, immune response,
  previous exposures, sensitivity or other
  causes.
Dose-Response

 Chemical A and B
               A

                     B




       LD50   LD50
Responses to Pollution

 Some  responses to exposure are
  reversible, some are not.
 Pollutants may undergo changes
  through the actions of ecological or
  biological processes…they may become
  more toxic or less toxic.
 Some pollutants may act synergistically.
Infectious Agents

 Infectious diseases transmitted through
  the air, water and soil are a serious risk
  to humans and animals.
 Diseases due to poor sanitation are the
  greatest cause of death in developing
  countries.
Toxic Heavy Metals

   Naturally occurring metallic elements:
        MERCURY;
        CHROMIUM

        Gold;

        Silver;

        LEAD;

        Cadmium;

        Vanadium;

        Nickel;

        Bismuth;

        Arsenic;

        Selenium;

        Thallium.
Toxic Heavy Metals

 Do not degrade in the environment.
 Persistent in biological tissue.
 Actions found in CNS and tissues.
  – Especially dangerous to children and
    fetuses.
 Can   be biomagnified in food chains.
Organic Compounds

 Organic Compounds: composed of carbon
 Synthetic Organic Compounds: used in
  industrial processes
 Persistent Organic Pollutants: Synthetic
  organic compounds often containing chlorine,
  that do not easily break down in the
  environment.
 Hormonally Active Agents: Chemicals in the
  environment able to cause reproductive and
  developmental abnormalities in animals
Common Organic Pollutants

 Pesticides.
 Synthetic   organic solvents.
 PCBs.
 Dioxin (Times Beach, MO).
 Synthetic organic compounds.
Radiation Pollution

 Common     radiation sources:
 – Ionizing radiation:
    Gamma   rays;
    Beta Particles;

    Alpha Particles;

    X-rays.

 – Non-ionizing radiation:
    EMF,   microwaves.
Thermal Pollution

 The abnormal heating or cooling of
  natural waters.
 Affects on ecosystems readily observed.
     Dissolved  oxygen content can be changed
      (increase in temp., decreased dissolved
      oxygen);
     Disruption of spawning cycles;

 Whatmay cause this change in water
 temperature?
Air Pollution

 Particulates: small particles of dust, smog,
  aerosols or mists.
 May originate from natural or anthropogenic
  sources: mobile or nonmobile.
 Most particulates are not toxic but can
  contaminate the lungs and cause pulmonary
  or cardiovascular health problems.
 Particulates can interfere with photosynthesis
  and lung function in animals.
Air Pollution

 Volatile organic compounds;
 NESHAPS;
 NAAQS:
 Criteria vs. Noncriteria Pollutants;
 Attainment vs. Non-Attainment Areas.
 Permit Program.
Noise Pollution

 Noise: Unwanted sound.
 Sound waves measured by intensity of
  waves using sound level meters (dBs on
  the A, B or C scale).
 Noise exposures may lead to stress-
  induced illnesses.
 Permanent or temporary (shifts)
  hearing loss.
Acute vs. Chronic Effects

  Acute  effects: Begin immediately or
   soon after exposure occurs.
  Exposure usually exceeds safe
   thresholds.
  Effects may be reversible.
  Chronic effects: Exposure to low level
   concentrations over a long period of
   time.
  Effects may not be reversible.
Dose-Response and Ecological
Gradients
  Organisms    that are generally located
   nearest to the pollutant source show the
   most severe and acute effects of
   exposure.
  Tolerance of organisms vary along
   ecological gradients.
  Tolerance of organisms is an indication
   of the ability of an organism to resist or
   withstand exposure.
Tolerance to Exposure

 Tolerance   is dependent on:
     Behavior (avoidance mechanisms);
     Physiology and detoxification;

     Genetic adaptability.
Risk Assessment

 Four   basic steps:
  –   Hazard identification;
  –   Toxicity assessment;
  –   Exposure assessment;
  –   Risk characterization.
 Risk   management.
Precautionary Principle

 The  idea that in spite of the fact that full
 scientific certainty is often not available
 to prove cause and effect, we should
 still take cost-effective precautions to
 solve environmental problems where
 there exists a threat of potentially
 serious and/ or irreversible
 environmental damage

				
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posted:9/17/2011
language:English
pages:28