Water Pollution: Causes, Consequences, and Solutions - Prof. Sujay Kaushal, Study notes of Environmental Science

Download Water Pollution: Causes, Consequences, and Solutions - Prof. Sujay Kaushal and more Study notes Environmental Science in PDF only on Docsity! Geology 120 Water Pollution In an age when man has forgotten his origins and is blind even to his most essential needs for survival, water along with other resources has become the victim of his indifference. -- Rachel Carson Extra Credit Opportunity! Pick up to 5 questions that you lost points on On a separate sheet of paper, tell us (in complete sentences): What was the correct answer and why were the rest of the answers incorrect? Hand in your corrected answers AND your exam in class (not accepted by e-mail) by Thursday April 14 with your section number/TA Drinking water % of population with access to safe drinking water (UNICEF) 1 BILLION people worldwide lack access to clean drinking water 2.5 BILLION by 2030! Water Pollutants Pathogenic Organisms • Disease causing microorganisms (ex: cholera, typhoid, hepatitis, dysentery, cryptosporidiosis) • 1993- 403,000 sick, 4400 hospitalized • Human fecal coliform bacteria used as measure of pollution • Escherichia coli (E. coli) • Waterborne disease largely eliminated in US  separation of sewage and drinking water Outbreaks made worse by natural disasters Water Pollutants Oxygen-demanding waste • Organic material decays via aerobic bacteria • Decay consumes oxygen • BOD (biochemical oxygen demand) – measure of oxygen used for bacterial decomposition • High BOD = high level of decaying matter • Unnatural sources include: agricultural runoff and urban sewage Water Pollutants Nutrients • Algae blooms can: • blanket surface, block sunlight to plants below • Consume oxygen during decomposition, potentially killing fish and other aquatic animals Water Pollutants Oil • Largest discharges usually from oil tankers • 1989 Exxon Valdez spilled roughly 11 million gallons http://whyfiles.org/168oil_spill/2.html http://whyfiles.org/168oil_spill/index.html Water Pollutants Oil – Exxon Valdez cleanup efforts Boomers to contain the oil Skimming, collecting, and removing oil from the water High pressure hot water washing shores Saving wildlife in rehabilitation facilities 4. Acids – Mine tailings in sulfide and coal mines – Acidic water absorbs heavy metals and kills plants Water Pollutants Toxic Substances 4 FeS2 + 15 O2 + 14 H2O  4 Fe(OH)2 + 8 H2SO4 Pyrite + Oxygen + Water  Iron Hydroxide + Sulfuric Acid Water Pollutants Sediment • Greatest water pollutant by volume • Depletes soil as a resource • Reduces water quality • May deposit undesirable materials on productive croplands http://aslo.org/photopost/showphoto.php?photo=802&size=big& papass=&sort=1&thecat=504 Is it always a negative effect? Water Pollutants Thermal Pollution • Artificial heating of water • Mainly industrial operations and power plants • Heated water contains less oxygen • T of water affects growth rates of different species www.greenworld.org.ru/map/termo03.gif Burnin’ River! • Industrialization and rivers- NOT perfect together! • June 22, 1969 the Cuyahoga River caught fire in Cleveland – burned in 1868, 1883, 1887, 1912, 1922, 1936, 1941, 1948, and 1952 • Some River! Chocolate-brown, oily, bubbling with subsurface gases, it oozes rather than flows. "Anyone who falls into the Cuyahoga does not drown," Cleveland's citizens joke grimly. "He decays". . . -- Time Magazine 1969 Some sources include: underground leaks above ground spills – infiltration above ground chemical use – infiltration (agriculture) saltwater intrusion ** Groundwater pollution 13.1 Saltwater intrusion: results from overpumping of groundwater in coastal areas Groundwater pollution Wastewater Treatment • wastewater reclamation reduces stress on water supplies • contaminated water must be treated www.chagrin-falls.org/Services/waterworks.html Wastewater Treatment Septic-tank sewage disposal: • underground tank collects waste  bacterial degradation of solids • liquids drain into ground; further purification occurs • geologic factors affect suitability of septic systems • soil, depth to water table or bedrock, topography Wastewater Treatment Wastewater-treatment plants: • primary treatment • removes 30 to 40% of pollutants • screening removes larger particles • settle out to form mud like sludge • sludge goes to digester; wastewater goes to second stage