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