How much is too much?

1. How much is too much?

2. Minor Spill in Local Watershed • Yesterday a loaded sewage truck slid off the bridge crossing the Clearwater River. The truck’s contents spilled into the river and due to the swift current, the sewage was carried away before clean-up crews could be dispatched. Today, at the Rocky Mountain House treatment plant, located at the junction of the Clearwater and North Saskatchewan Rivers, an e-coli concentration of 0.00001 ppth was detected.

3. Spill in Local River – Effects Unknown • Yesterday a loaded sewage truck slid off the bridge crossing the Clearwater River. The truck’s contents spilled into the river and due to the swift current, the sewage was carried away before clean-up crews could be dispatched. Today, at the Rocky Mountain House treatment plant, located at the junction of the Clearwater and North Saskatchewan Rivers, an e-coli concentration of 10 ppb was detected.

4. Catastrophic Events May Change Local River Forever • Yesterday a loaded sewage truck slid off the bridge crossing the Clearwater River. The truck’s contents spilled into the river and due to the swift current, the sewage was carried away before clean-up crews could be dispatched. Today, at the Rocky Mountain House treatment plant, located at the junction of the Clearwater and North Saskatchewan Rivers, an e-coli concentration of 10 000 ppt was detected.

5. After reading the three newspaper articles, which “event” will have the greatest effect on the environment? Why???

7. What is a pollutant? • - any material/form of energy that will cause harm to a living organism • - can be a physical, chemical, or biological harm that threatens the health or survival of that organism

8. What is pollution? • - any alteration of the environment producing a condition that is harmful to living things

9. How do we express concentrations of pollutants? • - ppm – 1 mg/kg • - ppb • - even ppt – cadmium becomes toxic at 17 ppt (heavy metals – density of 5 g/cm3) • 1 quarter in a stack 2000 km high!! • - percent – food (fat in milk)

10. Toxicity • - the ability of a material to cause harm to an organism • - acute – serious symptoms after only one exposure • - chronic – symptoms appear after extended exposure

11. LD50 – lethal dose 50 • - a common measurement of toxicity • refers the dose of a chemical that will kill 50% of the tested population

12. Acceptable Risk • What is considered acceptable? • - pros outweigh the cons • - toxicity different for different people • - tests rarely done on humans • - results are guesses from lab rat/mice information

13. Thalidomide • treatment of insomnia, lupus, and arthritis • - caused birth defects – lack of/severely shortened limbs

14. Saccharin • sweetener (Sweet n’ Low) • - discovered in 1879 – 500 times sweeter than sugar • - produces cancer in some lab animals

15. Evaluation of Risk • - most poisons are natural (called toxins) • - for every 1 molecule of man-made pesticide in our diet, there are 10 000 molecules of natural pesticides that we ingest. • - Fungicides sprayed on crops can cause cancer, however, molds that grow on crops is also carcinogenic.

16. Monitoring the Environment Biological indicators – aquatic invertebrates, types of fish, top of the food chain, microbiological indicators Chemical factors – dissolved oxygen, acidity, heavy metals, pesticides, plant nutrients, salts