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
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introduced one-way flow of flushing domestic and industrial wastewater into
natural waterways.
Name and describe the facility and the process used to remove debris, grit,
particulate organic matter, colloidal and dissolved organic matter, and dissolved
nutrients from wastewater.
 Debris and grit: rages, plastic bags, coarse sand, gravel and other objects
flushed down toilets or washed through storm drains. Removed by
preliminary treatment. Then by a bar screen and then a grit chamber.
 Particulate organic material: fecal matter, food wastes from garbagedisposal units, toilet paper, and other matter that tends to settle in still
water. They flow through a large tank called primary clarifiers.
 Colloidal and dissolved organic material: very fine particles of particulate
organic material, bacteria, urine, soaps, detergents, and other cleaning
agents. Biological treatment is used, uses organisms. These organisms
feed on the materials.
 Dissolved inorganic material: nitrogen phosphorus, and other nutrients
from excretory wastes and detergents. It is disposed through the process
of biological nutrient removal.
Why is secondary treatment also called biological treatment? What is the
principle involved? What are the two alternative techniques used?
Secondary treatment is also called biological treatment because it uses
organisms—natural decomposers and detritus feeders. The two alternative
techniques are the trickling-filter system and the activated-sludge system.
What are the principles involved in, and what is accomplished by the removal of
biological nutrients from waste? Where do nitrogen and phosphate go in the
process?
With increased awareness of the problem of cultural eutrophication,
secondary activated-sludge systems have been added and are being
modified and operated in a manner that both removes nutrients and
oxidizes detritus, in a process known as biological nutrient removal.
Nitrogen get converted by bacteria back to nonnutritive nitrogen gas in the
atmosphere called denitrification. Phosphorus is removed as the excess
organisms are removed from the system.
Name and describe three methods of treating raw sludge, and give the end
products(s) that may be produced from each method.
 Anaerobic Digestion – a process of allowing bacteria to feed on the
detritus in the absence of oxygen. The end products of this decomposition
are carbon dioxide, methane, and water.
 Composting – Raw sludge is mixed with wood chips or some other waterabsorbing material to reduce the water content. Bacteria and other
decomposers break down the organic materials to rich humus-like
materials that make an excellent treatment for poor soil.
 Pasteurization – sludge is heated sufficiently to kill any pathogens. The
product is a dry, odorless organic pellet.
How may sewage from individual homes be handled in the absence of municipal
collection systems? What are some problems with these on-site systems?
In the absence of municipal collection systems are septic tank and
leaching fields. The problems are that the on-site systems frequently fail,
resulting in unpleasant sewage backup into homes and pollution of
groundwater and surface waters.
10. Describe and compare submerged aquatic vegetation and phytoplankton. Where
and how does each get nutrients and light?
Submerged aquatic vegetation are aquatic plants rooted in bottom
sediments and growing under water. Submerged aquatic vegetation
depends on the penetration of light through the water for photosynthesis.
Phytoplankton is any of the many species of photosynthetic
microorganisms that consist of single cells or small groups of cells that
live and grow freely suspended near the surface in bodies of water. They
float around absorbing light.
11. Explain the difference between oligotrophic and eutrophic waters. Describe the
sequential process of eutrophication.
Oligotrophic is when it is nutrient poor and hence unable to support much
phytoplankton. Eutrophic is nutrient-rich water supporting an abundant
growth of algae or other aquatic plants at the surface. The sequential
process of eutrophication starts with nutrient enrichment, and proceeds to
the growth and die-off of phytoplankton, the accumulation of detritus, the
growth of bacteria, and, finally, the depletion of dissolved oxygen and the
suffocation of higher organisms.
12. Distinguish between natural and cultural eutrophication.
Natural eutrophication is a normal process. Cultural eutrophication is the
accelerated eutrophication caused by humans.
13. What is being done to establish nutrient criteria?
Beginning in 2001, the EPA began publishing water quality nutrient
criteria aimed at preventing and reducing the eutrophication that impacts
so many bodies of water.
14. How does the NPDES program address point-source pollution by nutrients?
The NPDES permitting process is the basic regulatory tool for reducing pointsource pollutants. Under the Clean Water Act, “anyone discharging pollutants
from any point source into waters of the U.S. [must] obtain an NPDES permit
from EPA or an authorized state.” More than 400,000 facilities are now
regulated by way of NPDES permits.
15. Describe the TMDL program. How does it address nonpoint-source pollution,
and what role do water quality criteria play in the program?
The TMDL program does the following:
 Identify the pollutants responsible for degrading a body of water.
 Estimate the pollution coming from all sources (point and
nonpoint).
 Estimate the ability of the body of water to assimilate the
pollutants while remaining below the threshold designating poor
or inadequate water quality.
 Determine the maximum allowable pollution load.
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Within a margin of safety, allocate the allowable level of
pollution among the different sources such that the water quality
standards are achieved.
16. What are some of the important issues relating to water quality in public policy?
Some of the important issues relating to water quality in public policy are
nonpoint-source pollution, the construction of new wastewater treatment
facilities, storm-water discharges, combined and separate sewer overflows,
wetlands protection, and animal feeding operations.
Chapter 21
1. Give three examples each of natural and anthropogenic air pollutants.
Natural – smoke, gases, and particles.
Anthropogenic – nitrogen oxides, nitric acid, and carbon monoxide.
2. What naturally occurring cleanser helps to remove pollutants from the
atmosphere? Where does it come from?
Hydroxyl radical (OH) oxidizes many gaseous pollutants to products that
are harmless or that can be brought down to the ground or water by
precipitation.
3. Describe the origin of industrial smog and photochemical smog. What are the
differences in the cause and appearance of each?
Industrial smog is a combination of smoke and fog. It’s an irritating,
grayish mixture of soot, sulfurous compounds, and water vapor.
Photochemical smog is produced when several pollutants from automobile
exhausts—nitrogen oxides and volatile organic carbon compounds—are
acted on by sunlight. The difference between the two is that industrial
smog, or gray smog, occurs when coal is burned and the atmosphere is
humid where as photochemical smog, or brown haze, occurs when
sunlight acts on vehicle pollutants.
4. What are the major primary air pollutants and their sources?
 Particulates (soot, smoke, metals, and carbon from combustion; dust, salts,
metal, and dirt from wind erosion; atmospheric reactions of gases.)
 Volatile Organic Compounds (Incomplete combustion of fossil fuels;
evaporation or solvents and gasoline; emission from plants.)
 Carbon Monoxide (Incomplete combustion of fuels.)
 Nitrogen Oxides (From nitrogen gas due to high combustion temperatures
when burning fuels.)
 Sulfur Oxides (Combustion of sulfur-containing fuels, especially coal.)
 Lead (Combustion of sulfur-containing fuels, especially coal.)
 Air toxics (Industry and transportation.)
5. What are secondary pollutants, and how are they formed?
Secondary pollutants are ozone, peroxyacetyl nitrates, sulfuric acid, and
nitric acid. It’s formed when primary pollutants undergo further reactions
in the atmosphere and produce additional undesirable compounds.
6. Distinguish between emissions and ambient concentrations. How are they
measured?
The EPA Office of Air and Radiation tracks trends I national emissions of
the primary pollutants from all sources. The EPA also follows air quality
by measuring ambient concentrations of the pollutants at thousands of
monitoring stations across the country.
7. What is the difference between an acid and a base? What is the pH scale?
An acid is any chemical that releases hydrogen ions when dissolved in
water. A Base is any chemical that releases hydroxide ions when
dissolved in water. The pH scale goes from 0-7 and each number on the
scale represents the negative logarithm of the hydrogen ion concentration,
expressed in grams per liter.
8. What two major acids are involved in acid deposition? Where does each come
from?
Two major acids are involved in acid deposition are sulfuric acid and
nitric acid.
9. What impact does air pollution have on human health? Give the three categories
of impact and distinguish among them.
The impact that air pollution has on human health is that it is a threat to
the respiratory system. The three categories of impact are Chronic Effects
(caused by long term exposure), Acute Effects (air pollution reaches levels
that cause death, although such deaths usually occur among people already
suffering from critical respiratory or heart disease or both), Carinogenic
Effects (the heavy-metal and organic constituents of air pollution include
many chemicals known to be carcinogenic I high doses. Linked to cancer
and heart conditions)
10. Describe the negative effects of pollutants on crops, forests, and other materials.
Which pollutants are mainly responsible for these effects?
The negative effects of pollutants on crops, forests, and other materials are
that they are being destroyed and these are thing we rely on. Sulfur
dioxide is the main pollutant responsible however it is the exposure to the
ozone that is the main problem.
11. How can a shift in environmental pH affect aquatic ecosystems? In what other
ecosystems can acid deposition be observed? What are its effects?
A shift in environmental pH affects aquatic ecosystems because they are
used to the pH level they are in and they will become severely stressed if it
changes even only 1 level. Acid deposition can also be observed in forests
as well. The acidic precipitation draws the calcium out causing the trees
to freeze in the winter and also it affects the soil and no longer helps them
grow.
12. What are the National Ambient Air Quality Standards, and how are they used?
The NAAQS are the allowable levels of ambient criteria air pollutants set
by EPA regulation. The primary standard for each pollutant is based on
the presumed highest level that can be tolerated by humans without
noticeable ill effects.
13. Discuss ways in which the Clean Air Act Amendments of 1990 address the
failures of previous legislation.
The Clean Air Act Amendments of 1990 address the failures of previous
legislation by making each state develop a State Implementation Plan that
is required to go through a process of public comment before being
submitted to the EPA for approval. Regions of the US that have failed to
attain the required levels must submit attainment plans, based on
reasonably available control technology (RACT) measures.
14. What technological and political changes are taking place in the United States to
reduce acid deposition?
Technological and political changes that are taking place in the US to
reduce acid deposition are with Title IV of the clean Air Act Amendments
of 1990, which addressed the acid-deposition problem by mandating
reductions in both sulfur dioxide and nitrogen oxide levels.
15. What are some recent air pollution programs that deserve our attention?
Some recent air pollution programs that deserve our attention are the New
Source Review Program, and the Acid Rain program.