Topic 4 Pages

 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 nameSourceApproximate LD50’s (ppm) Botulinum toxin AClostridium botulinum bacterium Tetanus toxin AClostridium tetani bacterium DioxinContaminant in some herbicides and in PCB’s 0.03 NicotineCigarette smoke0.86 StrychinePesticide5.0 SolaninePotatoes6.0 ChlordaneInsecticide40.0 Dieldreninsecticide80.0

 V_n0 V_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