Topic 4Pages 213- 221

You need to filter or boil water for at least 5 min to be safe to remove Giardia, a parasite.◦ Causes intestinal illness or “Beaver Fever”

Pollutant:◦ Any material, or form of energy, that will cause

harm to a living organism May result in physical, chemical or biological

mechanisms that will threaten the health and survival of an organism

Pollution:◦ Any alteration of the environment producing a

condition that is harmful to living things Ex: DDT

At what point does the concentration of a pollutant become a problem?

Does it happen when the pollutant causes the immediate death of an organism?

When the pollutant is only somewhat harmful?

Perhaps when the pollutant is present at a level that you can detect?

When you reduce the concentration of a solution.◦ You ADD water!

Toxicity◦ Ability of a chemical to cause harm to an organism

Acute toxicity◦ Ability of a chemical to cause harm to an organism

with only one exposure Chronic toxicity

◦ Ability of a chemical to cause harm to an organism only AFTER the chemical accumulates to a specific level after many exposures overtime.

What types of factors affect toxicity in one’s body?◦ Differences in body mass, metabolism, type of

lifestyle

Common measurement of toxicity Refers to the dose of a chemical that will kill

50% of the population that it is testing.◦ Takes resistance into account

-Table 3.4 (page 218) - Parts per million (ppm)

- This is a way of expressing very dilute concentrations of substances. Just as per cent means out of a hundred, so parts per million or ppm means out of a million.

Toxin name Source Approximate LD50’s (ppm)

Botulinum toxin A Clostridium botulinum bacterium

0.00000003

Tetanus toxin A Clostridium tetani bacterium

0.000005

Dioxin Contaminant in some herbicides and in PCB’s

0.03

Nicotine Cigarette smoke 0.86

Strychine Pesticide 5.0

Solanine Potatoes 6.0

Chlordane Insecticide 40.0

Dieldren insecticide 80.0

https://www.youtube.com/watch?v=QkpA0IJV_n0

Describe both sides – careful conservation vs. geoengineering

Choose your position. Write a supporting paragraph.

1. Why is it difficult to establish risks for chemical exposure? (list 4)

2. Why is thalidomide an issue?3. Describe the controversy of the LD50 in

caffeine.

4. Topic 4 booklet questions