CH. 20: WATER POLLUTION By: Alexa Tsaganos and Cricket Slattery

Core Case Study: Lake Washington

20.1 What are the Causes and Efects of Water Pollution? Key terms: Water pollution, Point sources, non point sources

20.1 Key Focus Water pollution causes illness and death in humans and other species and disrupts ecosystems

20.1 Key Focus The chief sources of water pollution are agricultural activities, industrial facilities, and mining, but growth in population and resource use makes it increasing worse

Major Water Pollutants and Their Sources Infectious agents (pathogens)  Human and animal wastes Oxygen-demanding wastes  sewage, animal feedlots, food processing facilities, pulp mills Plant nutrients  sewage, animal wastes, inorganic fertilizaers Organic chemicals  industry, farms, households Inorganic chemicals  Industry, households, surface runoff Sediments  land erosion Heavy metals  unlined landfills, household chemicals, minign refuse, industrila discharges Thermal  electric power and industrial plants

Common Diseases Transmitted to Humans, through contaminated Drinking Water Bacteria: typhoid fever, cholera, bacterial dysentery, enteritis Viruses: infectious hepatitis (type B), poliomyelitis Parasitic protozoa: amoebic dysentery, giardiasis, cryptosporidum Parasitic worms: schistosomiasis, ancylostomiasis

Science Focus: Testing Water For Pollutants Indicators of water quality: ½ cup of water must contain no colonies of coliform bacteria (for drinking), level of dissolved oxygen (good: 8-9 ppm at 20 degrees celsius) Gravely polluted if DO < 4 ppm Chemical analysis, indicator species, genetic engineering, colorimeters, turbidity

20.2 What Are the Major Water Pollution Problems in Streams and Lakes? Key terms: eutrophication, cultural eutrophication

20.2 What Are the Major Water Pollution Problems in Streams and Lakes? While streams are extensively polluted worldwide by human activities, they can cleanse themselves of many pollutants if we do not overload them or reduce their flows.

20.2 Key Focus Addition of excessive nutrients to lakes from human activities can disrupt lake ecosystems, and prevention of such pollution is more effective and less costly to clean up.

Individuals Matter John Beal and Hamm Creek

Case Study India’s Ganges River: Religion, Poverty, Population Growth, and Health

Case Study Pollution in the Great Lakes

20.3 What Are the Major Pollution Problems Affecting Groundwater and Other Drinking Water Sources? Chemicals used in agriculture, industry, transportation, and homes can spill and leak into groundwater and make it undrinkable.

20.3 Key Focus There are simple ways and complex ways to purify drinking water, but protecting it through pollution prevention is the least expensive and most effective strategy.

Case Study A Natural Threat from Arsenic in Groundwater

Case Study Protecting Watersheds Instead of Building Water Purification Plants

20.3 Solutions: Groundwater Pollution Prevention: Find subsitutes for toxic chemicals, keep toxic chemicals out of the environment, install monitorign wells near landfills and underground tanks, require leak detectors on underground tanks, Ban hazardous waste disposal in landfills and injection wells, store harmful tanks with leak detection and collection systems Cleanup: Pump to surface, clean, and return to aquifer (very expensive), inject microorganisms to clean up contamination (less expensive but still costly), Pump nanoparticles of inorganic compounds to remove polutants (still being devloped)

20.4 What Are The Major Water Pollution Problems Affecting Oceans? Key Terms: harmful algae blooms, oxygen-depleted zones, dead zones, crude petroleum, refined petroleum

20.4 Key Focuses Ocean pollution originates on land and includes oil and other toxic chemicals and solid wastes, which threaten aquatic species and other wildlife and disrupt marine ecosystems. The key to protecting the oceans is to reduce the flow of pollutants from land and air and from streams emptying into these waters.

20.4 Ocean pollution is a growing problem – cruise ships – Viruses – Harmful algae blooms Ocean oil pollution is serious – Exxon Valdez – Prestige – Volatile organic hydrocarbons – Cleanup

Oxygen-depleted Zones

20.5 How Can We Best Deal with Water Pollution? Key Terms: septic tank, primary sewage treatment, secondary sewage treatment

20.5 Key Focuses Reducing water pollution requires preventing it, working with nature to treat sewage, cutting resource use and waste, reducing poverty, and slowing population growth. msG58 msG58

20.5 We need to reduce surface water pollution form nonpoint sources – Organic farming techniques – Pesticides Laws can help reduce water pollution from point sources – Federal Water Pollution Control Act of 1972 (later named the Clean Water Act) – 1987 Water Quality Act – Discharge Trading Policy

20.5 continued The US experience with reducing point-source pollution – Improvements from the Clean Water Act – Prevention Sewage treatment reduces water pollution – Septic tank – Primary sewage treatment – Secondary sewage treatment – Advanced or tertiary sewage treatment

Primary and Secondary Sewage Treatment