1. Environmental Health, Pollution, and Toxicology
Chapter 8

2. 8.1 Some Basics
Environmental health: disease that is determined by or related to environmental factors such as toxic chemicals, toxic biological agents, or radiation
Disease: an impairment of an individual’s health.

3. 8.1 Some Basics
Pollution: an unwanted change in the environment caused by the introduction of harmful materials or the production of harmful conditions
Contamination: making something unfit for a particular use through the introduction of undesirable materials

4. 8.1 Some Basics Toxin: substances that are poisonous to living things
Toxicology: science that studies toxins or suspected toxins
Carcinogen: toxin that causes cancer

5. 8.1 Some basics
Synergism: interaction of different substances. May amplify or make worse the effect of just one of those substances.

6. 8.1 Some Basics
Point sources: you can pinpoint exactly where the pollution is coming from
Ex: smoke stacks, pipes discharging into waterways
Nonpoint sources: more diffused and hard to figure out where it’s coming from
Ex: all the cars on the freeway, urban runoff

7. 8.1 Some Basics
Biomagnification: the chemical accumulates or increases concentration of a substance as it moves through the food web
AKA bioaccumulation
EX: Mercury in fish

8. 8.2 Categories of pollutants and toxins
Infectious agents – caused by bacteria, viruses, or fungus.
Think of some examples?
Toxic Heavy Metals (metals with a large atomic weight)
Mercury, lead, cadmium, nickel, etc.
Case Study: Minimata in Japan

9. 8.2 Categories of pollutants and toxins
Organic compounds: compounds that have carbon in them
EX: pesticides, pharmaceuticals, food additives
Many manufactured by people
Polluting and toxic
They do not easily break down in the environment
They are soluble in fat and can accumulate in living tissue

10. 8.2 Categories of pollutants and toxins
EX: PCBs – shipped from GE in Massachusetts, used in household appliances
They leaked into the soil or damaged
PCBs went into the algae, the insects ate the algae, then they were eaten by shrimp and fish, eventually eaten by people

11. 8.2 Categories of pollutants and toxins
Dioxin: one of the most toxic human-made chemicals
Not usually made intentionally; it is a waste product of some chemical reactions
Led to cancer in humans (as well as other animals)
Labeled Carcinogen by EPA
STILL hasn’t been banned or regulated by government.

12. 8.2 Categories of pollutants and toxins
Hormonally active agents (HAAs)
Messed with the hormones of an animal (including humans!!)
Many found in pesticides and herbicides
DDT – used as a pesticide, thinned out shells out bald eagle

13. 8.2 Categories of pollutants and toxins
Nuclear Radiation
Can lead to serious problems, including cancer
Thermal pollution (heat pollution) heat is released into water or air
Can come from volcanic eruptions, agricultural burning
Power plants use water to cool the equipment down. Can affect wildlife near by it

14. 8.2. Categories of pollutants and toxins
Particulates: small particles of dust in the air that can come into our lungs
Asbestos: minerals that are in the form of small, elongated particles
Used in houses for insulation

15. 8.2 Categories of pollutants and toxins
Noise pollution: unwanted sound

16. 8.4 Old and New Environmental Health Problems
Pandemic – disease that spreads rapidly across wide regions of the planet affecting a high proportion of the population
EX: Bubonic Plague
EX: HIV/AIDS
Pigs and other animals such as chickens in commercial farms can increase the possibility of new diseases evolving and spreading to humans

17. 8.4
Hospitals with large numbers of sick people can become a breeding ground for disease
In 2006, E. coli spreading

18. 8.5 General Effects of Pollutants
Almost every part of the human body is affected by one pollutant or another.
Dose response: effect of a certain chemical on an individual depends on the dose
EX: Fluorine: a little bit keeps tooth decay at bay, but too much can lead to osteoporosis, a disease characterized by loss of bone mass.
LD-50: crude approximation of a chemical’s toxicity
Dose at which 50% of the population dies, or the Lethal Dose 50.

19. 8.5
ED-50 (effective dose 50) dose that causes an effect in 50% of the observed subjects
TD-50 (toxic dose 50) is the dose that is toxic to 50% of the observed subjects.
Threshold – a level below which no effect occurs and above which effects begin to occur
Tolerance: ability to resist or withstand stress from exposure to a pollutant or harmful condition