Review Day 2

1. Review Day 2

2. Human Diet

3. Math Problem • If an average refrigerator uses 500 watts of energy per hour on a daily basis, and your energy cost is $0.11 per kwh, approximately how much does the energy used by the refrigerator cost per month? • a. $1.30 • b. $13 • c. $40 • d. $55 • e. $132

4. Long Division... Last time. • 10/5 • 176/160 • 1305/30

5. Water Review Water Pollution

6. WATER POLLUTION: SOURCES, TYPES, AND EFFECTS • Water pollution is any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired uses. • Point source: specific location (drain pipes, ditches, sewer lines). • Nonpoint source: cannot be traced to a single site of discharge (atmospheric deposition, agricultural / industrial / residential runoff)

7. Major Water Pollutants and Their Effects

9. Major Water Pollutants and Their Effects • Water quality and dissolved oxygen (DO) content in parts per million (ppm) at 20°C. • Only a few fish species can survive in water less than 4ppm at 20°C.

10. POLLUTION OF FRESHWATER STREAMS • Most developed countries have sharply reduced point-source pollution but toxic chemicals and pollution from nonpoint sources are still a problem. • Stream pollution from discharges of untreated sewage and industrial wastes is a major problem in developing countries.

11. Cultural Eutrophication • Eutrophication: the natural nutrient enrichment of a shallow lake, estuary or slow moving stream, mostly from runoff of plant nutrients from the surrounding land. • Cultural eutrophication: human activities accelerate the input of plant nutrients (mostly nitrate- and phosphate-containing effluents) to a lake. • 85% of large lakes near major population centers in the U.S. have some degree of cultural eutrophication.

12. Polluted air Pesticides and fertilizers Hazardous waste injection well Deicing road salt Coal strip mine runoff Buried gasoline and solvent tanks Gasoline station Pumping well Cesspool, septic tank Water pumping well Waste lagoon Sewer Leakage from faulty casing Landfill Accidental spills Discharge Unconfined freshwater aquifer Confined aquifer Confined freshwater aquifer Groundwater flow

13. POLLUTION OF GROUNDWATER • It can take hundreds to thousand of years for contaminated groundwater to cleanse itself of degradable wastes. • Nondegradable wastes (toxic lead, arsenic, flouride) are there permanently. • Slowly degradable wastes (such as DDT) are there for decades.

14. Leaking tank Aquifer Bedrock Water table Groundwater flow Free gasoline dissolves in groundwater (dissolved phase) Gasoline leakage plume (liquid phase) Migrating vapor phase Water well Contaminant plume moves with the groundwater

15. Solutions Groundwater Pollution Prevention Cleanup Pump to surface, clean, and return to aquifer (very expensive) Find substitutes for toxic chemicals Keep toxic chemicals out of the environment Inject microorganisms to clean up contamination (less expensive but still costly) Install monitoring wells near landfills and underground tanks Require leak detectors on underground tanks Pump nanoparticles of inorganic compounds to remove pollutants (may be the cheapest, easiest, and most effective method but is still being developed) Ban hazardous waste disposal in landfills and injection wells Store harmful liquids in aboveground tanks with leak detection and collection systems

16. Industry Nitrogen oxides from autos and smokestacks, toxic chemicals, and heavy metals in effluents flow into bays and estuaries. Urban sprawl Bacteria and viruses from sewers and septic tanks contaminate shellfish beds Cities Toxic metals and oil from streets and parking lots pollute waters; Construction sites Sediments are washed into waterways, choking fish and plants, clouding waters, and blocking sunlight. Farms Runoff of pesticides, manure, and fertilizers adds toxins and excess nitrogen and phosphorus. Red tides Excess nitrogen causes explosive growth of toxicmicroscopic algae, poisoning fish and marine mammals. Closed shellfish beds Closed beach Oxygen-depleted zone Toxic sediments Chemicals and toxic metals contaminate shellfish beds, kill spawning fish, and accumulate in the tissues of bottom feeders. Oxygen-depleted zone Sedimentation and algae overgrowth reduce sunlight, kill beneficial sea grasses, use up oxygen, and degrade habitat. Healthy zone Clear, oxygen-rich waters promote growth of plankton and sea grasses, and support fish. Fig. 21-10, p. 505

17. OCEAN POLLUTION • Harmful algal blooms (HAB) are caused by explosive growth of harmful algae from sewage and agricultural runoff.

18. Solutions Coastal Water Pollution Prevention Cleanup Reduce input of toxic pollutants Improve oil-spill cleanup capabilities Separate sewage and storm lines Ban dumping of wastes and sewage by maritime and cruise ships in coastal waters Sprinkle nanoparticles over an oil or sewage spill to dissolve the oil or sewage without creating harmful by-products (still under development) Ban ocean dumping of sludge and hazardous dredged material Protect sensitive areas from development, oil drilling, and oil shipping Require at least secondary treatment of coastal sewage Regulate coastal development Use wetlands, solar-aquatic, or other methods to treat sewage Recycle used oil Require double hulls for oil tankers

19. Reducing Water Pollution through Sewage Treatment • Raw sewage reaching a municipal sewage treatment plant typically undergoes: • Primary sewage treatment: a physical process that uses screens and a grit tank to remove large floating objects and allows settling. • Secondary sewage treatment: a biological process in which aerobic bacteria remove as much as 90% of dissolved and biodegradable, oxygen demanding organic wastes.

20. Reducing Water Pollution through Sewage Treatment • Primary and Secondary sewage treatment.

21. Solutions Water Pollution • Prevent groundwater contamination • Reduce nonpoint runoff • Reuse treated wastewater for irrigation • Find substitutes for toxic pollutants • Work with nature to treat sewage • Practice four R's of resource use (refuse, reduce, recycle, reuse) • Reduce air pollution • Reduce poverty • Reduce birth rates

22. Environmental Organizations and Industries • http://webecoist.momtastic.com/2008/09/24/25-environmental-agencies-and-organizations/