Key Concepts • Types, sources, and effects of water pollutants • Major pollution problems of surface water • Major pollution problems of groundwater • Reduction and prevention of water pollution • Drinking water quality Refer to Tables 22-1 and 22-2 p. 492 and 493
Types of Water Pollution INFECTIOUS AGENTS Examples: Bacteria, viruses, protozoa, and parasitic worms Major Human Sources: Human and animal wastes Harmful Effects: Disease Water Contamination - Milwaukee
OXYGEN-DEMANDING WASTES Examples: Organic waste such as animal manure and plant debris that can be decomposed by aerobic (oxygen-requiring) bacteria Major Human Sources: Sewage, animal feedlots, paper mills, and food processing facilities Harmful Effects: Large populations of bacteria decomposing these wastes can degrade water quality by depleting water of dissolved oxygen. This causes fish and other forms of oxygen-consuming aquatic life to die.
INORGANIC CHEMICALS • Examples: Water-soluble 1) acids, (2) compounds of toxic metals such as lead (Pb), arsenic (As), and selenium Se), and (3) salts such as sodium chloride (NaCl) in ocean water and fluorides (F–) found in some soils • Major Human Sources: Surface runoff, industrial effluents, and household cleansers • Harmful Effects: Can (1) make fresh water unusable for drinking or irrigation, (2) cause skin cancers and crippling spinal and neck damage (F–), (3) damage the nervous system, liver, and kidneys (Pb and As), (4) harm fish and other aquatic life, (5) lower crop yields, and (6) accelerate corrosion of metals exposed to such water. • Minamata Bay
Types of Water Pollution ORGANIC CHEMICALS Examples: Oil, gasoline, plastics, pesticides, cleaning solvents, detergents Major Human Sources: Industrial effluents, household cleansers, surface runoff from farms and yards Harmful Effects: Can (1) threaten human health by causing nervous system damage (some pesticides), reproductive disorders (some solvents), and some cancers (gasoline, oil, and some solvents) and (2) harm fish and wildlife.
RADIOACTIVE MATERIALS • Examples: Radioactive isotopes of iodine, radon, uranium, cesium, and thorium • Major Human Sources: Nuclear and coal-burning power plants, mining and processing of uranium and other ores, nuclear weapons production, natural sources • Harmful Effects: Genetic mutations, miscarriages, birth defects, and certain cancers
PLANT NUTRIENTS Examples: Water-soluble compounds containing nitrate (NO3 –), phosphate (PO43–), and ammonium (NH4+) ions Major Human Sources: Sewage, manure, and runoff of agricultural and urban fertilizers Harmful Effects: Can cause excessive growth of algae and other aquatic plants, which die, decay, deplete water of dissolved oxygen, and kill fish. Drinking water with excessive levels of nitrates lowers the oxygen-carrying capacity of the blood and can kill unborn children and infants (“bluebaby syndrome”).
HEAT (THERMAL POLLUTION) • Examples: Excessive heat • Major Human Sources: Water cooling of electric power plants and some types of industrial plants. Almost half of all water withdrawn in the United States each year is for cooling electric power plants. • Harmful Effects: Lowers dissolved oxygen levels and makes aquatic organisms more vulnerable to disease, parasites, and toxic chemicals. When a power plant first opens or shuts down for repair, fish and other organisms adapted to a particular temperature range can be killed by the abrupt change in water temperature—known as thermal shock.
Types of Pollution SEDIMENT Examples: Soil, silt Major Human Sources: Land erosion Harmful Effects: Can (1) cloud water and reduce photosynthesis, (2) disrupt aquatic food webs, (3) carry pesticides, bacteria, and other harmful substances, (4) settle out and destroy feeding and spawning grounds of fish, and (5) clog and fill lakes, artificial reservoirs, stream channels, and harbors.
Hypoxia and Anoxia Area Most Effected: Gulf of Mexico Long Island Sound WHY? Eutrophication – Nutrient pollution Chesapeake Bay Largest US estuary Relatively shallow Slow “flushing” action to Atlantic Major problems with dissolved O2
Figure 22-6Page 498 Biomagnification Water 0.000002 ppm Phytoplankton 0.0025 ppm Herring gull 124 ppm Herring gull eggs 124 ppm Zooplankton 0.123ppm Lake trout 4.83 ppm Rainbow smelt 1.04 ppm Silent Spring
Pollution Sources and Effects Nonpoint Sources Point Sources Rhine River Minamata Bay Oxygen Sag Curve Factors that influence dissolved oxygen in the water Biological Oxygen demand Recovery
Case Study: The Great Lakes An Industrial Legacy Great Lakes Fig. 22-8 p. 500
Groundwater Pollution Gasland Love Canal Causes: Low flow rates Spills Low oxygen Landfill leachate Few bacteria pesticides /fertilizers Cold temperatures waste lagoons Times Beach Aquifer cleanup
Ocean Pollution Message from the waves Fig. 22-11 p. 504 Troubled Waters
Oil Spills • Sources: offshore wells, tankers, pipelines and storage tanks • Effects: death of organisms, loss of animal insulation and buoyancy, smothering • Significant economic impacts • Mechanical cleanup methods: skimmers and blotters • Chemical cleanup methods: coagulants and dispersing agents
Name 3 types of water pollution. Identify the sources, and effects of each. What is bioaccumulation? What is biomagnification? Give an example of a pollutant that exhibits biomagnification.
Solutions: Preventing and Reducing Surface Water Pollution Nonpoint Sources • Reduce runoff • Buffer zone vegetation • Reduce soil erosion Point Sources • Clean Water Act (1972) • Water Quality Act (1965): Established water purity standards with states retaining initial responsibility for water purity.
Water Laws: Clean Water Act (1972):Established the basic structure for regulating discharges of pollutants into the waters of the United States. It gave the EPA the authority to implement pollution control programs such as setting waste-water standards for industry. Federal Water Pollution Control Act (1948):Created comprehensive programs for eliminating or reducing the pollution of interstate water and improving the sanitary condition of surface and underground water supplies. Safe Drinking Water Act (1974):Established standards for safe drinking water in the United States. Ocean Dumping Ban Act (1988):Made it unlawful for any person to dump or transport for the purpose of dumping sewage, sludge, or industrial wastes into the ocean. Oil Spill Prevention and Liability Act (1990):Strengthened the EPA's ability to prevent and respond to catastrophic oil spills. Source Water Assessment Program—SWAP (1996):Required states to identify sources of public drinking water supplies and assess susceptibility to contamination. Source Water Protection Program—SWPP (1996):Encouraged states to adopt a community-based approach to preventing water pollution. Surface Water Treatment Rule—SWTR (1996):Addressed control of microbial pathogens, including cryptosporidium.
Water Treatment Municipal Waste Water Treatment
Wastewater treatment High-Tech v. Low-Tech Hyperion Wastewater Treatment Plant – Los Angeles Solar Aquatic Waste Treatment Treating mining wastewater Z-weedDesalinization Wetlands treating sewage
Technological Approach: Septic Systems • Require suitable soils and maintenance Technological Approach: Sewage Treatment • Physical and biological treatment Fig. 22-15 p. 510 • Advanced Tertiary Treatment • Uses physical and chemical processes • Removes nitrate and phosphate • Expensive • Not widely used
“Municipal” Water Treatment Process" Coagulation: Alum and other chemicals are added to water to form tiny sticky particles, called floc, that attract dirt particles. Flocculation: The water is stirred slowly with paddles to mix the alum with the dirty water. Sedimentation: The water is no longer stirred and is allowed to settle. The heavy particles (floc) settle to the bottom and clear water moves off the top to the filtration chamber. Filtration: Water passes through filters that help remove even smaller particles. Our filters consist of gravel, sand, garnet and charcoal. Each layer filters out a smaller and smaller particle. The charcoal not only acts as a filter but neutralizes taste and odor. Disinfection: After filtration, the water moves into a disinfection chamber where it is mixed with chlorine. A small amount of chlorine is added to kill any bacteria or microorganisms that may be in the water. It is at this step that we also add a small amount of fluoride for dental health. Storage: Water is placed in a closed tank or reservoir where it flows through pipes to homes and businesses in the community
Drinking Water Quality • Purification of urban drinking water • Protection from terrorism • Purification of rural drinking water • Safe Drinking Water Act • Maximum contaminant levels (MCLs) • Bottled water
Water Video Clips Composting Toilets & Z-weed Drinking Water from a Contaminated Aquifer Desalinization Drugs in water
Persistent Organic pollutants (POPs) Unknown Pollution Threats Pharmaceuticals in the water supply PCBs 1Pesticide 2Industrial Chemical 3Byproduct PAHs