Environmental Chemistry Topics 4+5

1. Environmental ChemistryTopics 4+5 How Much is Too Much

2. Pollution Pollution Is any alteration of the environment producing a condition that is harmful to living things. Pollutant Is any material, or form of energy, that will cause harm to a living organism. The harm may be the result of any physical, chemical or biological mechanism that threatens the health or survival of an organism.

3. Pollution and Pollutants

4. Pollution and Pollutants Questions to think about. At what point does the concentration of a pollutant become a problem? • When it causes immediate death? • When it is only somewhat harmful? • When you can detect or see the problem?

5. Toxicity Toxicity is the ability of a chemical to cause harm to an organism. The harm can be direct or from the substances that form in the organism. Acute Toxicity Symptoms occur after one exposure to that chemical. Chronic Toxicity When symptoms appear only after a chemical builds up to a dangerous level in the body.

6. Toxicity Heavy Metal: Very dangerous Lead and Mercury Lead: accumulates in the body – chronically toxic Lead Paint in old buildings (cause nerve damage) Mercury: accumulates in the body – chronically toxic Causes nerve damage and liver damage

7. Measuring Toxicity and its Potential for Harm How do we measure Toxicity? LD50 – Lethal Dose This refers to the dose of the toxin that will kill 50% of the population of the organisms Typically toxins are tested on animals or microbes. Clostridium botulinum: a bacteria produces a poison considered to be the most toxic substance known to man.

8. Toxicity and Acceptable Risk What is Acceptable Risk? It is hard to determine risk. Why? 1.a dose that kills one individual may not kill another 2. toxicity depends on how it enters the body 3. not all species react the same to chemicals Thalidomide: a chemical used in the 1950-60s. Used as a sleeping pill and by pregnant women to ease morning sickness Caused tremendous deformities in babies - extremely short limbs

9. Thalidomide Defects

10. Topic 4 Review Questions 1- 5 Page 221

11. TOPIC 5Environmental Monitoring Waste: All waste entering the environment are potentially dangerous – some are more dangerous than others Non-persistent waste: Waste that can be broken down into simple non-polluting components by nature. (Fertilizers, sewage) Persistent waste: pollutants that accumulate in the environment very slow break down (pesticides, heavy metals)

12. Persistent Waste (Pollutants) Pesticides Petroleum Products Heavy Metals

13. Waste Both persistent and non-persistent waste can be a problem if the concentrations are high enough to be harmful. How can we detect these waste? Typically pollutants make their way into the water supply – we have water quality tests Two tests Phosphates Nitrates

14. Phosphates & Nitrates in the Water Phosphates – source (laundry soap) * promotes plant growth * tremendous growth of algae Nitrates – source (fertilizers) * algae bloom – causes low oxygen levels * cause death of aquatic organisms Algae grows rapidly, die, break down. This process of decay strips a tremendous amounts of oxygen out of the water…causes death of other organisms

15. Winter Kill • Caused by too many nitrates and phosphates in the water. • Algae grows rapidly, dies, breaks down. • This process of decay strips a tremendous amount of oxygen out of the water… causes death of other organisms. • Winter is worse because of frozen over (no oxygen being added), snow cover (no sunlight for photosynthesis)

16. Algal Bloom

17. Biological Indicators and Water Quality Most types of pollution lower the ability of the environment to support life. In water this decreases the amount of oxygen in the water. Pollution will decrease the quality of the water, resulting in less diversity of organisms and less life. Biological Indicators (those organisms found in clean or polluted water) Trout and perch – need clean water and lots of oxygen Carp and Cat fish – tolerate polluted water

18. Biological Indicators Macro-invertebrates – most useful organisms for a biological indicator in water quality. Macro-invertebrates: visible to the eye, lack backbones * Crustaceans – crayfish * Molluscs – clams and mussels * Gastropods – snails * Oligochaetes – worms * Insects

19. Macro-invertebrates crayfish clams mussels snails worms

20. Point vs Non-point Sources Steps to stopping water pollution 1. Determining pollutants in water is the first step. 2. Monitoring changes in pollutants. 3. Track pollutants to the source. Point Sources – specific locations (ie. drainpipes) * easy to monitor and control Non-point Sources – non-specific location (ie. Feedlots, golf-courses) * hard to monitor and control – because the pollutant migrate…through water sources.

21. Topic 5 Review Questions 1-4 Page 235

22. Topic 6 – There Is No Away In Throwing • N.I.M.B.Y. – stands for NOT IN MY BACK YARD. • What are the potential negatives? • Blowing In The Wind – Air pollution and water pollution can travel great distances because of prevailing winds. Human activities are the greatest source of air pollution.

23. Stratospheric Ozone and CFCs Ozone protects us from ultraviolet rays which can cause skin cancer, cataracts (eye problems) and affects plankton. The ozone layer is thinning and has developed holes because of CFC’s (Chlorofluorocarbons). We find CFC’s in styrofoam, air conditioners, fridges and aerosol cans. CFC’s are very stable and last in the environment for a long time (Persistent Waste)

24. Water Waste Treatment(Urban) • Primary Treatment • Physical - filtering. sieving and settling • - waste water can be further treated with chlorine and returned to the environment as effluent. Waste material, called sludge, can be recycled as fertilizer or landfill.

25. Secondary Treatment • Biological - bacteria and micro-organisms decompose most of the remaining biodegradable waste.

26. Tertiary Treatment • Chemical • Removes dissolved nitrates, phosphates and undissolved solids from the effluent

27. Water Waste Treatment(Rural)

28. A septic tank is a large underground container that traps grease and large solids. The remaining liquid waste is distributed through pipes with holes (perforated); the pipes lead into a drainage area containing gravel. Bacteria and other micro-organisms in the gravel and soil break down the organic waste and use it as a source of food energy. This system mimics the way in which decomposers normally recycle biodegradable wastes. The septic tank is periodically pumped out to prevent overflow.

29. Biodegradable vs Non-Biodegradable Biodegradation occurs in the environment because living things (earthworms, bacteria and fungi) are actively breaking down organic substances, including many pollutants. They are able to use these as nutrients. Non Biodegradable substances take a long time to break down and usually can’t be used by organisms for food

30. Waste Management • The 4 R’s – Treatment of solid waste. • Reduce – Don’t make as much waste and the problem of disposal will take care of itself. • Reuse – Use an item for another use – Eg. Peanut butter jar for piggy bank

31. The 4 R’s - continued • Recycle – Break down materials to be used again. Eg. Pop cans, cardboard • Recover / Reclaim – Cleaning up polluted areas and increasing their ability to support life. Can also mean using substances to their fullest (Hot water heating)

32. Waste Management • Landfill Construction and Design

33. Page 252 – Topic 6 Review • Topic 4 – 6 Wrap Up – Page 253