Presentation is loading. Please wait.

Presentation is loading. Please wait.

Review Day 2.

Similar presentations

Presentation on theme: "Review Day 2."— Presentation transcript:

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

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
Natural capital degradation: water quality and dissolved oxygen (DO) content in parts per million (ppm) at 20°C (68°F). Only a few fish species can survive in water with less than 4 ppm of dissolved oxygen at this temperature. 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.

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 Unconfined freshwater aquifer Confined aquifer
Polluted air Pesticides and fertilizers Hazardous waste injection well Deicing road salt Coal strip mine runoff Buried gasoline and solvent tanks Pumping well Gasoline station Cesspool, septic tank Water pumping well Waste lagoon Sewer Landfill Leakage from faulty casing Accidental spills Figure 21.7 Natural capital degradation: principal sources of groundwater contamination in the United States. Another source is saltwater intrusion from excessive groundwater withdrawal (Figure 14-12, p. 315) (Figure is not drawn to scale.) Discharge Unconfined freshwater aquifer Confined aquifer Confined freshwater aquifer Groundwater flow

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 Contaminant plume moves with the groundwater
Leaking tank Aquifer Water table Bedrock Figure 21.8 Natural capital degradation: groundwater contamination from a leaking gasoline tank. As the contaminated water spreads from its source in a widening plume, it can be extracted by wells used to provide water for drinking and irrigation. 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 Groundwater Pollution
Solutions Groundwater Pollution Prevention Cleanup Find substitutes for toxic chemicals Pump to surface, clean, and return to aquifer (very expensive) 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 Figure 21.9 Solutions: methods for preventing and cleaning up contamination of groundwater. QUESTION: Which two of these solutions do you think are the most important? 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 and heavy metals in effluents flow into bays and estuaries. Cities
Industry Nitrogen oxides from autos and smokestacks, toxic chemicals, and heavy metals in effluents flow into bays and estuaries. Cities Toxic metals and oil from streets and parking lots pollute waters; Urban sprawl Bacteria and viruses from sewers and septic tanks contaminate shellfish beds 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 Figure 21.10 Natural capital degradation: residential areas, factories, and farms all contribute to the pollution of coastal waters and bays. According to the UN Environment Programme, coastal water pollution costs the world $16 billion annually—$731,000 a minute—due to ill health and premature death. 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 , p. 505

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

18 Coastal Water Pollution
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 Figure 21.14 Solutions: methods for preventing and cleaning up excessive pollution of coastal waters. QUESTION: Which two of these solutions do you think are the most important? 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 • Prevent groundwater contamination
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) Figure 21.18 Solutions: methods for preventing and reducing water pollution. QUESTION: Which two of these solutions do you think are the most important? • Reduce air pollution • Reduce poverty • Reduce birth rates

22 Environmental Organizations and Industries

Download ppt "Review Day 2."

Similar presentations

Ads by Google