Environmental Health

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Environmental Health
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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.

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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.

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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

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Measuring Pollutants

• Measuring depends on the substance
• Common Units
• ppm Parts per million
• ppb Parts per billion
• Micrograms per cubicle meter (measures air)

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Categories of Pollutants

• Infectious Agents
• Toxic Heavy Metals Organic Compounds
• Radiation
• Thermal Pollution
• Particulates
• Asbestos
• Electromagnetic Fields
• Noise Pollution
• Voluntary Exposure

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Environmental Health

• BUTTERFLY MODEL for an Ecosystem Context.

Biophysical Environment
Elements Home Workplace Health Care Neighborhoods
Political Institutions
Elements Air, Water Soil, Microbes Plants, Animals
Socioeconomic Environment
Biological and Behavioral Filters
Features Air Quality Food Quality Water Quality
Features Early Childhood Development Social
Support Empowerment Community
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Organism Response to Pollution

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

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Dose-Response

• Chemical A and B

A
B
DOSE
LD50
LD50
RESPONSE
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Responses to Pollution

• Some responses to exposure are reversible, some
  are not.
• Pollutants may undergo changes through the
  actions of ecological or biological
  processesthey may become more toxic or less
  toxic.
• Some pollutants may act synergistically.

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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.

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Toxic Heavy Metals

• Naturally occurring metallic elements
• MERCURY
• CHROMIUM
• Gold
• Silver
• LEAD
• Cadmium
• Vanadium
• Nickel
• Bismuth
• Arsenic
• Selenium
• Thallium.

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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.

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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

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Common Organic Pollutants

• Pesticides.
• Synthetic organic solvents.
• PCBs.
• Dioxin (Times Beach, MO).
• Synthetic organic compounds.

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Radiation Pollution

• Common radiation sources
• Ionizing radiation
• Gamma rays
• Beta Particles
• Alpha Particles
• X-rays.
• Non-ionizing radiation
• EMF, microwaves.

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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
• What may cause this change in water temperature?

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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.

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Air Pollution

• Volatile organic compounds
• NESHAPS
• NAAQS
• Criteria vs. Noncriteria Pollutants
• Attainment vs. Non-Attainment Areas.
• Permit Program.

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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.

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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.

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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.

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Tolerance to Exposure

• Tolerance is dependent on
• Behavior (avoidance mechanisms)
• Physiology and detoxification
• Genetic adaptability.

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Risk Assessment

• Four basic steps
• Hazard identification
• Toxicity assessment
• Exposure assessment
• Risk characterization.
• Risk management.

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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