Topic 4 How Much is Too Much Pollution

Topic 4 – How Much is Too Much – Pollution – Pgs. 213 - 221 Pollutant – _____________________________ Pollution - ______________________________ What are some of the items that pollute our water – that we test for? When is something harmful? How do we know? Example -

Quantitative Analysis – usually ppm or ppb so how do we get to this unit? Ex. 1 Yogurt has 7 mg of cholesterol per serving which is 125 g. What is the concentration in ppm? 1 st – ratio 7 mg/125 g = 0. 056 mg/g 2 nd – convert to mg/kg which is equal to a ppm 0. 056 x 1000 = 56 mg/kg = 56 ppm A mg/kg = ppm so always get to mg/kg first – labels help!!! Ex. 2

Toxicity Terms: (Page 217) Chemicals can have: 1) Acute Toxicity – serious symptoms after one exposure Examples: 2) Chronic Toxicity – chemical needs to accumulate first Examples: It is hard to know the amount of a chemical required to make it toxic. Why? (Chlorine at WEM) We have established some very specific toxicity measurements for some substances: Ex. LD 50 -The dose of a chemical that will kill 50% of the population to which it is applied. See table 3. 4 (I am Legend) - Where do the most harmful chemicals come from? ? _____________ Reading of page 219 and 220. What are some risks you accept? ? ?