chapter 14Review
In this chapter, we learned about the many sources of water pollution and their effects on humans and the environment. One prominent source of water pollution is the wastewater produced by humans and livestock. Wastewater can bring excessive nutrients to water bodies and be a source of disease-
Water pollution Wastewater Point source Nonpoint source Biochemical oxygen demand (BOD) Dead zone Eutrophication Cultural eutrophication Indicator species Fecal coliform bacteria Septic system Septic tank Sludge Septage Leach field Manure lagoon Acid deposition Perchlorates Polychlorinated biphenyls (PCBs) Thermal pollution Thermal shock Clean Water Act Safe Drinking Water Act Maximum contaminant level (MCL) | Solid waste material from wastewater. A dramatic change in water temperature that can kill organisms. Legislation that sets the national standards for safe drinking water. Nonchemical water pollution that occurs when human activities cause a substantial change in the temperature of water. A component of a septic system, made up of underground pipes laid out below the surface of the ground. A diffuse area that produces pollution. The standard for safe drinking water established by the EPA under the Safe Drinking Water Act. A layer of fairly clear water found in the middle of a septic tank. A large container that receives wastewater from a house as part of a septic system. A phenomenon in which a body of water becomes rich in nutrients. The amount of oxygen a quantity of water uses over a period of time at specific temperatures. A distinct location from which pollution is directly produced. A group of industrial compounds used to manufacture plastics and insulate electrical transformers, and responsible for many environmental problems. Legislation that supports the “protection and propagation of fish, shellfish, and wildlife and recreation in and on the water” by maintaining and, when necessary, restoring the chemical, physical, and biological properties of surface waters. Human-made pond lined with rubber built to handle large quantities of manure produced by livestock. The contamination of streams, rivers, lakes, oceans, or groundwater with substances produced through human activities. A group of harmful chemicals used for rocket fuel. Acids deposited on Earth as rain and snow or as gases and particles that attach to the surfaces of plants, soil, and water. A species that indicates whether or not disease-causing pathogens are likely to be present. A group of generally harmless microorganisms in human intestines that can serve as an indicator species for potentially harmful microorganisms associated with contaminated sewage. An increase in fertility in a body of water, the result of anthropogenic inputs of nutrients. In a body of water, an area with extremely low oxygen concentration and very little life. Water produced by livestock operations and human activities, including human sewage from toilets and gray water from bathing and washing of clothes and dishes. A relatively small and simple sewage treatment system, made up of a septic tank and a leach field, often used for homes in rural areas. |
Module 41 Wastewater from Humans and Livestock
Discuss the three major problems caused by wastewater pollution.
Because wastewater contains organic matter, decomposition by microbes can cause declines in the amount of oxygen available in water bodies and produce dead zones. Dead zones also occur where wastewater adds enough nutrients to a water body to cause eutrophication. Finally, wastewater can be a source of many harmful pathogens including viruses, bacteria, and protists.
Explain the modern technologies used to treat wastewater.
At low residential densities, septic systems can be used to treat sewage. At higher residential densities such as in cities, sewage treatment plants treat the collected sewage from thousands of people. For livestock operations that raise large numbers of animals, manure lagoons hold manure until it is broken down by bacteria and can be applied to agricultural fields.
Module 42 Heavy Metals and Other Chemicals
Explain the sources of heavy metals and their effect on organisms.
Among the heavy metals of most concern are lead, mercury, and arsenic. Lead can harm the nervous system and kidneys of fetuses; the major source of lead is old water pipes. Arsenic can cause cancers of the skin, lungs, kidneys, and bladder; it exists naturally in rocks that release arsenic into groundwater that people drink. Mercury is not particularly toxic, but bacteria in water convert it into methylmercury, which can damage the nervous systems of animals, including humans. Major sources of mercury include coal burning, garbage incineration, medical supplies, and cement manufacturing.
Discuss the sources and effects of acid deposition and acid mine drainage.
The major sources of acid deposition are industrial plants that burn coal and release sulfur dioxide and nitrogen dioxide into the atmosphere where they are converted into sulfuric acid and nitric acid. The major source of acid mine drainage is abandoned mines that contain pyrite rocks. When the mines become flooded with groundwater, rocks release hydrogen ions and any water that leaves the mine and goes into a stream can have a pH close to zero. Both sources of acid pollution cause a decline in aquatic pH to a point that many organisms cannot survive.
Explain how synthetic organic compounds can affect aquatic organisms.
Pesticides are designed to kill particular organisms, but their presence in water bodies can have lethal effects on a wide range of species. Pharmaceuticals including hormones can alter the physiology of organisms at very low concentrations and have a range of effects, including causing males to grow eggs inside their testes. Military compounds such as perchlorates used for rocket fuel and industrial compounds such as PCBs and PBDEs can also make their way into groundwater and water bodies.
Module 43 Oil Pollution
Identify the major sources of oil pollution.
The major sources of oil pollution are natural leaks from the ocean floor, oil spills from tankers, and drilling for undersea oil using offshore platforms.
Explain some of the current methods to remediate oil pollution.
When an oil spill occurs, several steps can be taken to remediate the problem. Contaminated wildlife are often washed to remove oil. Floating oil slicks can be surrounded by containment booms and then vacuumed off the surface of the water. Oil slicks can also be treated with chemicals that break up the oil before it can come to shore. Genetically modified bacteria are also being developed to consume oil in the water. There is currently no agreement on how to remove underwater plumes of oil.
Module 44 Nonchemical Water Pollution
Identify the major sources of solid waste pollution.
The major sources of solid waste are discarded materials from households and industries, sludge from wastewater treatment plants, and coal ash and coal slag that are produced when coal is burned.
Explain the harmful effects of sediment pollution.
Sediments that make their way into water bodies from natural sources, agricultural fields, and construction sites can reduce the ability of light to transmit into the water, which makes it difficult for plants and algae to grow. Sediments also can clog the gills of aquatic organisms.
Discuss the sources and consequences of thermal pollution.
Thermal pollution occurs when industries pump in cool water from a local water body, use the water for cooling purposes, and then return the much warmer water back to the water body. Many organisms cannot survive the shock of having the temperature of the environment substantially increase.
Understand the causes of noise pollution.
Noise pollution is primarily an issue of concern in oceans where noises come from the propellers of large ships, long-
Module 45 Water Pollution Laws
Explain how the Clean Water Act protects against water pollution.
The Clean Water Act has a goal of maintaining and, when necessary, restoring the chemical, physical, and biological properties of surface waters. It does this by setting water quality standards for various pollutants.
Discuss the goals of the Safe Drinking Water Act.
The Safe Drinking Water Act sets maximum contaminant levels that can be found in sources of drinking water including groundwater. The contaminants include microorganisms, disinfectants, organic chemicals, and inorganic chemicals.
Understand how water pollution legislation is changing in developing countries.
Developed countries have gone through a period of industrialization and water pollution followed by steps to improve their water quality. Most developing countries are in the stage of industrializing and, as a result, they commonly have problems of polluted surface and groundwater. As developing countries rise in affluence, they begin to have the desire and the financial ability to improve the quality of their water.