Environmental Problems, Their Causes, and Sustainability 1

Bad news. Now the Puget Sound is in trouble. Thereis growing concern about increased urban runoffcaused by the area’s rapidly growing population, overflowsof raw sewage, and large inputs of toxic materialsinto the sound.Taking pollution from one place (Lake Washington)and putting it somewhere else (Puget Sound) is anoutput approach that can be overwhelmed by a combinationof more people and more wastes. The way outis to prevent most wastes from reaching either of thesetwo bodies of water.Case Study: Pollution in the Great Lakes—Hopeful ProgressPollution of the Great Lakes has dropped significantlybut there is a long way to go.The five interconnected Great Lakes of North America(Figure 22-8) formed about 10,500 years ago when retreatingglaciers melted and poured water into theland basins carved out by the slowly moving glaciers.These lakes contain at least 95% of the fresh surfacewater in the United States and one-fifth of the world’sfresh surface water.The Great Lakes basin is also home for about 30%of the Canadian population and 14% of the U.S. population.At least 38 million people obtain their drinkingwater from these lakes.Despite their enormous size, these lakes are vulnerableto pollution from point and nonpoint sources.One reason is that less than 1% of the water enteringthese lakes flows out to the St. Lawrence River eachyear. Another reason is that in addition to land runoffthese lakes get atmospheric deposition of large quanti-CANADASt. Louis R.MINNESOTAIOWASilver BayWISCONSINNipigon BayThunder BayLakeSuperiorMenominee R.Jackfish BayMICHIGAN Manistique R. St. Mary’s R.Green BayFox R.Sheboygan R.MichiganLakeLakeHuronSpanish R.MICHIGANSaginawBaySaginaw R.SystemSt. Clair R.Thames R.Detroit R.Rouge R.Raisin R.Maumee R.Black R.GrandR.Lake EriePenetary BaySturgeonBayLakeAshtabula R.Cuyahoga R.Rocky R.OntarioNiagara FallsNiagara R.Buffalo R.BayofQuinteSt. Lawrence R.PENNSYLVANIANEW YORKILLINOIS INDIANA OHIOGreat Lakes drainage basinMost polluted areas, according to the Great Lakes Water Quality Board"Hot spots" of toxic concentrations in water and sedimentsEutrophic areasFigure 22-8 Natural capital degradation: the Great Lakes basin and the locations of some of its water qualityproblems. The Great Lakes region is dotted with several hundred abandoned toxic waste sites listed by theEPA as Superfund sites to receive cleanup priority. (Data from U.S. Environmental Protection Agency)500 CHAPTER 22 Water Pollution