Bio36_20_WaterPollution - 1 2 3 1 2 4 1 2 5 6 Overview Ch....

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1 Overview • Ch. 20: Water Pollution – Pollutants – Wastewater treatment – Eutrophication Dead Zones • Hypoxia: lacking oxygen • Eutrophication – Enrichment by nutrients • Dead zones – Gulf of Mexico •1993: zone doubled in size •Zone continues to grow – Chesapeake Bay •Seasonal appearance of zone – 400 worldwide •95,000 square miles Industrial Revolution • Wastes emptied into nearest waterway – Industrial wastes – Sewage • Health problems – Not recognized – “Price of progress” • 1950s: synthetic organics • 1969: Cuyahoga River – Caught fire • 1948: Federal Water Pollution Control Act – Technical assistance • 1972: Clean Water Act – EPA given the task of restoring waterways Sources of Water Pollution • Point sources – Discharge from a specific entity – E.g., factories • Nonpoint sources – Poorly defined – Scattered over broad areas – E.g., agricultural runoff • Control strategies – Reduce or remove sources – Treat water before releasing •Remove pollutants or convert to harmless Types of Water Pollution • Pathogens • Organic matter • Chemical pollutants – Inorganic chemicals – Organic chemicals • Sediments • Nutrients Pathogens 1 2 3 1 2 4 1 2 5 6
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2 • Infectious agents – Bacteria, viruses, protozoans, worms • Monitoring for sewage contamination – Fecal coliform test E. coli is an indicator organism • Public health – Instruction in personal & domestic hygiene Organic Matter • Decomposition uses up dissolved oxygen – DO only 10 ppm in cold water (less in warm) – Hypoxia • Biochemical oxygen demand (BOD) – Measure of organic material in water Chemical Pollutants • Inorganic chemicals – Heavy metals •Pb, Hg, As, Ni, etc.
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Bio36_20_WaterPollution - 1 2 3 1 2 4 1 2 5 6 Overview Ch....

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