Water Resources & PollutionGloria BlancoWilfredo Amiot
Water ResourcesWater is a vital resource that sustains life, moderates climate, shapes the earth’s surface, and provides habitat for many organisms.
Freshwater Less than 1% of global water is available as freshwater. Some sources Include: Groundwater- Water which infiltrates the ground and perco- lates downward through the soil, gravel, and porous rock layers until it reaches a non- permeable rock layer. Zone of Aeration- First few levels below the soil’s surface which traps mostly air instead of water. Zone of Saturation- Deeper subsurface layer with all porous space filled with water.
Freshwater Source: Groundwater Water Table- The upper limit of the zone of saturation. Natural/Lateral Recharge- Groundwater in aquifers are replenished through the percolation of precipitation OR the movement of water from rivers and streams. Watershed- Drainage basin; land surrounding large bodies of water that contribute to surface runoff.
Depletion Populations rely heavily on aquifers to run properly. Overdraft- Withdrawals exceed recharge and water tables begin to fall. Land Subsidence- Overdraft from the the aquifer can cause the land above the reservoir collapse.
Increasing Supplies Desalination- Process which removes dissolved salts from ocean water or from brackish seas and lakes. Reverse Osmosis- Push saline water through membranes that separate salt from water. Distillation- Evaporating the water and collecting it as it condenses, leaving the salt behind.
Water Pollution Water Pollution: is any chemical, biological, or physical change in water quality that has harmful effects on living organism or uses:
Major Categories of water pollutants Infectious Agents: such as bacteria, viruses and protozoa Oxygen-Demanding wastes: organic waste Inorganic chemicals: acids, compounds of toxic metals and salts Organic chemicals: oil, gasoline and pesticides and plastic Plant nutrients: nitrates and phosphates Sediment: soil and silt Radioactive Materials: uranium, radon Thermal Pollution: Excessive heat.
Water pollution can come fromsingle or multiple sources. Point Sources: discharge pollutants at specific locations through drain pipes, ditches, or sewer lines into the water surface. Such as factories. Nonpoint Sources: are scattered and diffuse and cannot be traced to any single site of discharge. Such as runoff and precipitation.
Human activities can overload lakes withplant nutrients and kill marine life. Eutrophication: the process by which a body of water becomes enriched indissolved nutrients (such as phosphatesand nitrates) that stimulate the growthof aquatic plant life usually resulting in the depletion of dissolved oxygen. Cultural Eutrophication: is theprocess of human activities near urbanor agricultural areas that input excess plant nutrients into bodies of water.
In parts of the world’s oceans are dump sitesfor toxic materials and garbage from ships. Dredge spoils: The discharge from a dredge, materials often with toxic metals and scrape from bottoms of harbor and rivers to maintain shipping channel. Septic Tank: A sewage-disposal tank in which a continuous flow of waste materialis decomposed byanaerobic bacteria.
Treatments to reduce water pollution Primary sewage treatment: It is a physical process that uses screens and a grit tank to remove large floating objects and solids such as sand and rock.
Water Pollution Secondary sewage treatment: It is a biological process in which aerobic bacteria remove up to 90% of dissolved and biodegradable, oxygen-demanding organic wastes.
Advanced or tertiary sewage treatment: It is a series of specialized chemical and physical process that remove specific pollutants left in the water after primary and secondary treatment.
Questions:1. Of the following which constitutes the greatest percent of use for water withdrawn in the world today(a). Flushing toilets in residential homes(b). Drinking water (human consumption)(c). Smelting of metal in manufacturing(d). Irrigation for food production(e). Coolant water for electricity produced by coal2. Which of the following would least likely reduce the nutrient loading into the Chesapeake Bay estuary?(a). Replanting of riparian zones and sea grass beds(b). Upgrade of current sewage treatment plants(c). Improvement of manure containment lagoons in feedlots(d). Government subsidies for cotton crops(e). Re-introduction of native oyster beds
Questions:3. Which of the following river conditions would yield the highest dissolved oxygen content?(a). Fast-moving cold water, large amounts of submerged vegetative biomass(b). Slow-moving cool waters, large amounts of emergent vegetative biomass(c). Slow-moving warm waters, low amounts of submerged vegetative biomass(d). Stagnant, warm water with large clumps of algae(e). Warm water with little vegetative biomass4. In coastal areas, withdrawing groundwater to the point where lateral recharge into the oceans becomes limited can cause(a). Hypoxic conditions(b). Increased vertical recharge(c). Saltwater intrusion(d). Change in the zone of aeration(e). drought
5. The loss of riparian land along a riverwould cause which of the following? I. Increased Flooding II. Decreased turbidity III. Increased non-point source pollution(a). I only(b). II only(c). III only(d). I and III(e). I, II, and III
Questions:6. The process of human activities near urban or agricultural areas that input excess plant nutrients into lakes is known as?(a). artificial fertilization(b). cultural eutrophication(c). thermal pollution(d). lake stratification(e). synthetic primary production7. Which of the following is NOT a nonpoint-source pollutant?(a). sediment loading from erosion(b). runoff of pesticides from cropland(c). animal wastes from feedlots(d). fertilizers runoff from urban lawns(e). a sewage treatment plant effluent pipe8. A type of wastewater treatment that includes some form of physical cleaning isI. primary treatmentII. secondary treatmentIII. tertiary treatment(a). I only(b). II only(c). III only(d). I and III(e). I, II, III
Questions Continued:9. Which of the following will result in accelerated eutrophication when introduced into streams, lakes and bays?(a). bacteria and viruses(b). pesticides(c). herbicides(d). phosphates(e). acid wastes and salts10. The largest source of oil pollution found in the ocean is from:(a). urban and industrial runoff from the land(b). oil tanker accidents transporting oil between port cities(c). offshore drilling rigs in the Gulf of Mexico(d). pipeline leaks near coastal areas(e). the Alaskan pipeline
Answers:1. (d). Irrigation for food production2. (d). Government subsidies for cottoncrops3. (a). Fast-moving cool water, largeamounts of submerged vegetative biomass4. (c). Saltwater intrusion5. (d). I and III
Answers:6. (b). Cultural eutrophication7. (e). A sewage treatment plant effluent pipe8. (d). I and III9. (d). Phosphates10. (a). Urban and industrial runoff from the land
Free Response Question The Colorado River runs 1,450 miles from the headwaters of the Rocky Mountains to the Gulf of California. The river has many dams, aqueducts, and canals that divert water in order to supply water for electricity, irrigation, recreation, and domestic use. a) Describe and discuss two environmental problems that are associated with water diversion. b) If there is a shortage of water, choices will have to be made as to whether water should be diverted to urban areas, agricultural areas, or natural ecosystems. Make an argument for diverting water for urban consumption and an argument for permitting the flow of water to natural areas. c) Identify another example (other than the Colorado River) of a large-scale water-diversion project. Discuss two environmental problems that have resulted, or might result, from this project.
Part A a). Describe and discuss two environmental problems that are associated with water diversion. Four points: one point can beearned for each of the first twoappropriate descriptions ofenvironmental problems of water diversion (additional descriptions are not scored); one point can beearned for a discussion of each ofthe environmental problemspreviously described.