Learning Objectives
After reading and studying this chapter, students should:
• Be able to define water pollution and discuss some of the common water pollutants.
• Understand the methods for treating groundwater pollution.
• Understand the important processes related to wastewater treatment and renovation.
Chapter Summary
This chapter focuses on several aspects of water pollution. The chapter begins with a discussion of the
importance of water pollution to water supplies worldwide, and a description of several common water
pollutants. Subsequent sections focus on surface water pollution, including point sources and non-point
sources, and on aspects of groundwater pollution, including its importance, sources, assessment, and
treatment. The chapter closes with a discussion of water-quality standards, of wastewater treatment,
including septic systems, municipal treatment systems, wetland treatment of wastewater, and
wastewater renovation and recycling, federal legislation related to pollution prevention and treatment,
and what can be done to reduce the effects of water pollution.
Chapter Outline
I. An overview of water pollution
A. Water pollution
2. judged according to the intended use of the water, its departure from the norm, and public
health or ecological impacts
4. see Case History: North Carolina’s Bay of Pigs
B. Primary water pollution problem worldwide
2. chemical pollution is also an emerging problem
II. Selected water pollutants
A. Oxygen-demanding waste
1. organic matter in streams is decayed by aerobic bacteria
3. biochemical oxygen demand: measure of oxygen used for bacterial decomposition
5. urban areas may add considerable BOD during storms
B. Pathogenic organisms
2. fecal coliform bacteria level is used as indicator of biological pollution
4. epidemics of waterborne disease largely eliminated in the United States by separating sewage
and drinking water, but incidents remain
1
14
4
Water Pollution
6. outbreaks exacerbated by natural disasters
C. Nutrients
2. cultural eutrophication results from high human-caused concentrations of nitrogen and
phosphorous
4. Gulf of Mexico: summer “dead zone” off Louisiana
D. Oil
2. largest discharges from oil-tanker accidents
4. Deepwater Horizon spill, 2010
E. Toxic substances
1. synthetic organic chemicals
2. heavy metals: lead, mercury, zinc, cadmium, and arsenic
3. radioactive waste
F. Sediment
1. greatest water pollutant by volume
3. reduces water quality
4. may deposit undesirable materials on productive croplands
G. Thermal pollution
1. artificial heating of waters
3. heated water contains less oxygen, can favor undesirable species
4. can enhance survival of desirable species during winter
III. Surface-water pollution and treatment
A. Point sources of surface-water pollution
2. sources are typically pipes from industrial or municipal facilities
3. typically treated on-site and regulated by permit
B. Non-point sources of surface-water pollution
1. diffuse and intermittent sources
3. rural sources generally from agriculture, mining, forestry (see A Closer Look: Acid Mine
Drainage)
4. non-point sources are difficult to control and contains variety of pollutants
C. Reduction of surface-water pollution: the Cuyahoga River success story
1. in the United States, concerted effort is underway to reduce water pollution
3. Cuyahoga River success story: most polluted river in 1960s is now much cleaner
D. Urban flooding and water pollution
2. wastewater treatment plants may be overwhelmed
IV. Groundwater pollution and treatment
A. One-half of the United States population relies on groundwater for drinking water supplies
Water Pollution
1. hazard level
2. problem of groundwater pollution becomes more apparent as testing becomes more common
3. effects of chronic exposure to low pollutant levels are not known
B. National water-quality assessment program
1. significant investment in pollution prevention and significant improvement in water quality
over past 25 years
3. Goals
a. to carefully describe current water-quality conditions for many of the freshwater streams
4. Delaware River basin project
C. Water quality and stream ecosystems in the United States
2. studies
3. western streams are generally healthier than eastern streams
D. Saltwater intrusion
2. has caused problems in New York, Florida, California, and other states
3. as cone of depression forms in freshwater, a cone of ascension develops in adjacent saltwater
E. Groundwater treatment
1. reducing pollution of groundwater is a difficult task
3. variety of methods exist for treating groundwater (Table 12.2)
V. Water-quality standards
A. Health effects of chronic exposure to very low levels of chemical contaminants is unknown
B. Safe Drinking Water Act of 1974
1. expanded in 1986 to include 83 contaminants
C. EPA has set standards for many contaminants
2. National Primary Drinking Water Standards (Table 14.5)
VI. Wastewater treatment
A. Contaminated waters must be treated before release into United States waters
1. wastewater reclamation and use can reduce stress on water supplies
B. Septic-tank sewage disposal
2. underground tank collects waste and permits bacterial degradation of solid portions
4. geologic factors affect suitability of septic systems
5. septic system failure
C. Wastewater treatment plants
1. primary treatment
Chapter 14 – Instructor’s Manual
3. advanced treatment and wastewater reclamation
4. handling and disposal of sludge
D. Wetlands as wastewater treatment sites
1. wetlands can treat wastewater or other poor-quality water
3. Louisiana
4. Phoenix, Arizona
E. Wastewater renovation
1. wastewater renovation and conservation cycle
3. Clayton County, Georgia: wastewater applied to pine forest
5. Orange County, California
VII. Federal legislation
A. Rewriting of major environmental laws
1. mid 1990s: debate and controversy regarding water pollution
3. strong public support for clean air and water caused backlash
B. Imposition of new rules
1. President Clinton imposed new pollution controls in 2000
2. President Bush suspended some rules in 2001, but the regulations are now in place
3. Objections to controls
a. the requirements would be costly
b. local and state governments are better suited to implement water pollution rules
VIII. What can be done to reduce effects of water pollution?
1. Developing and refining better ways to evaluate water pollution problems and their impact on
aquatic life and the health of people.
3. Developing products and processes that minimize production of water pollutants and their
release into the environment.
Answers to Review Questions and Critical Thinking Questions
Review Questions
1. Water pollution is the degradation of water quality as measured by biological, chemical, or physical
criteria.
3. The level of fecal coliform is used as an indicator of biological pollution, and is used because the
direct measurement of individual pathogens is difficult.
4. Cultural eutrophication of water bodies is caused by rapid increase in algae and other plant life, in
5. Point sources are discrete and localized sources of pollution, while non-point sources are more
widespread and diffuse, representing no single, specific source.
Water Pollution
7. Saltwater intrusion is the movement of saltwater into coastal freshwater aquifers, and is caused by
8. Primary, secondary, and advanced wastewater treatments refer to the level of treatment performed.
Primary treatment involves the removal of particulate matter, while secondary treatment involves the
10.Wastewater renovation and conservation involves the application of wastewater to crops, natural
Critical Thinking Questions
1. A student addressing this assignment will need to examine land uses in the area and identify the
2. An answer to this question will depend largely on local conditions and wastewater treatment
processes. If there is a geologically and biologically suitable area for wastewater renovation and
3. A student addressing this question will need to consider the sources of their perceptions regarding