ESciChap17 21 - Chapter 17 1. Define, pollution, pollutant,...

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Chapter 17 1. Define, pollution, pollutant, nonbiodegradable, point source, and nonpoint source of pollutants. Pollution – the presence of a substance in the environment that, because its chemical composition or quantity, prevents the functioning of natural processes and produces undesirable environmental and health effects. Pollutant – any material that causes pollution. Nonbiodegradable – products that resist attack and breakdown by detritus feeders and decomposers and consequently accumulate in the environment. Point source – involve the discharge of substances from factories, sewage systems, power plants, underground coalmines, and oil wells. Nonpoint source – poorly defined and scattered over broad areas. 2. Discuss each of the following categories of water pollutants and the problems they cause: pathogens, organic wastes, chemical pollutants, and sediments. Pathogens – disease-causing bacteria viruses, and other parasitic organisms. They cause sickness and death. Organic wastes – wastes that contain organic matter that creates serious problems if it enters bodies of water untreated. Chemical pollutants – inorganic chemicals that include heavy medals (lead, mercury, arsenic, nickel, and so forth), acids from mine drainage (sulfuric and nitric acids), and road salts. Organic chemicals are another group of substances found in polluted waters. These pollutants are toxic even at low concentrations. Some may pass up the food chain in a process called biomagnification. Sediments – As natural landforms weather, and especially during storms, a certain amount of sediment enters streams and rivers. Erosion from farmlands, deforested slopes, overgrazed rangelands, construction sites, mining sites, stream banks, and roads can greatly increase the load of sediment entering waterways. 3. How are water quality standards determined? Distinguish between water quality criteria pollutants and maximum contaminant levels. Water quality standards are determined by the National Recommended Water Quality Criteria. Criteria pollutants are toxic chemicals (the majority), but many are also natural chemicals or conditions that describe the state of water, such as nutrients, hardness, and pH. Maximum contaminant levels are a drinking water standard; the highest allowable concentration of a pollutant in a drinking water source. 4. Give a brief history of how humans’ handling of sewage wastes has changed as the risks and potential benefits have become better understood. Before the late 1800s, the general means of disposing of human excrement was the outdoor privy. Seepage contaminated drinking water and caused disease. The flush toilet was introduced, and sewers were tapped into storm drains. This introduced one-way flow of flushing domestic and industrial wastewater into
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natural waterways. 5.
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This homework help was uploaded on 04/07/2008 for the course ENV 1112 taught by Professor Wear during the Spring '08 term at Catawba College.

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ESciChap17 21 - Chapter 17 1. Define, pollution, pollutant,...

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