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Environmental Health, Pollution, and Toxicology

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Title: Environmental Health, Pollution, and Toxicology


1
Chapter 8
  • Environmental Health, Pollution, and Toxicology

Big Question Why Are Even Tiny Amounts of
Pollutants a Major Concern?
2
Some Basics
Volcanic gases spewing from Mt. St Helens
adversely affected air quality
3
Terminology
  • Pollution refers to an unwanted change in the
    environment caused by introducing harmful
    materials or by producing harmful conditions
  • Contamination implies making something unfit for
    a particular use through the introduction of
    undesirable materialA toxin is a substance that
    is poisonous (toxic) to people and other living
    things
  • Toxicology is the science that studies chemicals
    that are or could be toxic
  • A carcinogen is a toxin that increases the risk
    of cancer

4
  • Synergism is an important concept
  • It is the interaction of different substances,
    resulting in a combined effect that is greater
    than the effects of the separate substances

5
  • How do pollutants get into the environment?
  • Point sources
  • Area sources (also called non-point sources)

6
  • Mobile sources

7
Categories of Pollutants
  • Infectious Agents
  • Toxic Heavy Metals
  • Organic Compounds
  • Thermal pollution
  • Particulates
  • Electromagnetic Fields
  • Noise

8
Heavy Metals
9
Toxic Pathways
  • One pathway is biomagnification
  • accumulation or increase in the concentration of
    a substance in living tissue as it moves through
    a food web
  • Also known as bioaccumulation

10
Pathways for Mercury
11
Mercury and Minamata, Japan
  • A strange illness began to affect animals and
    people in the middle of the 20th century
  • It was first recognized in birds, cats, and then
    families of fishermen
  • A vinyl chloride factory on the bay used mercury
    in an inorganic form
  • Methylation increased absorption into fish tissue
    from the water by a factor of 100

The crippled hand of a minamata disease
victim Photo Wikipedia
12
Organic Compounds
13
(No Transcript)
14
Dioxin-contaminated site in South Park, Seattle.
15
Hormonally Active Agents (HAAs)
  • HAAs are also persistent organic pollutants
  • HAAs include a wide variety of chemicals, such as
    some herbicides, pesticides, and phthalates
  • Studies link HAAs to reproductive abnormalities
    among wildlife
  • Florida alligators
  • Do HAAs play a role in human diseases?
  • Link with breast cancer?

16
Thermal Pollution
17
Wet and Dry Cooling Towers
18
Particulates
19
  • Removal of chrysolite asbestos in homes and
    public buildings is extremely expensive, and
    there is little evidence that it actually poses a
    hazard

20
Electromagnetic Fields
21
Noise Pollution
22
Voluntary Exposure
23
General Effects of Pollutants
24
Dose and Response
  • Large amounts of any substance can be dangerous,
    while an extremely small amount can be relatively
    harmless
  • Even true for water!
  • Copper, chromium, and manganese are some chemical
    elements required by animals in small amounts but
    toxic in higher amounts

25
Dose-Response
26
Risk Assessment and RiskManagement
  • Risk assessment is the process of determining
    potential health effects of pollutants. It
    involves
  • Identification of the hazard
  • Dose-response assessment
  • Exposure assessment
  • Risk characterization

27
  • Risk management requires us to make scientific
    judgments in conjunction with technical, legal,
    political, social, and economic considerations
  • Risk assessment and risk management can lead to
    arguments since the scientific opinions may be
    open to debate
  • The appropriate action may be to apply the
    Precautionary Principle
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