QUESTIONS 13, PART A
1. Which of the major inorganic substances might indicate contamination by sewage?
2. What are the major inorganic substances discussed in Part A that may be detrimental to human health?
3. Iron and chloride are major inorganic substances that adversely affect drinking water. Are they health
hazards according to the USEPA tables in this exercise?
4. a. What are the health hazards of excessive fluoride?
Excessive bone formation (bone disease), calcification of ligaments, and mottled teeth.
(Check online for the latest EPA regulations and research.)
b. Why is fluoride listed in Tables 13.1 and 13.2?
5. For each of the following contaminants in drinking water, list the potential health effects and their
sources.
See Table 13.1 for health effects and sources. (Check footnotes and online for additional explanations
and research.)
Arsenic
6. Use the information in Table 13.1 to help answer the following.
a. What is the purpose or role of adding disinfectants to drinking water?
b. What are the potential health effects (if any) of the disinfectant byproducts (listed in Table 13.1) that
are produced during disinfection of drinking water?
c. For control of Giardia lamblia (and most other biologicals in the water), what two techniques are
employed?
d. A treatment technique that controls the corrosiveness of water is used to limit copper and lead
contaminants in drinking water. Why is corrosion a factor in copper and lead contamination? Low pH
Use information in Tables 13.4 and 13.5 to answer the questions below.
7. a. What water quality factors suggest that the North Dakota farm well is contaminated?
b. What are the most likely sources of contamination in this well?
8. a. What is the most likely cause of contamination of the domestic well in Ohio?
Oil field brines or road salt are the most likely causes.
b. Could the water be used for cooking? Explain.
9. a. What is the most likely source of contamination of Big Four Hollow Creek?
b. Could this water be detrimental to health if consumed? Explain.
c. What taste should it have?
It should have a sour or bitter taste because of acidity and a metallic taste because of high iron content.
10. Why do you think that the well water in Wichita is more highly mineralized than the well water in
Shreveport? (Consider climate as well as possible differences in geology.)
11. Why does the public water supply in Seattle contain fewer dissolved solids than the supply in
Buffalo? (Consider geology, climate, and topography.)
Much surface runoff occurs in the Seattle area because of the high rate of precipitation. Dilution therefore
12. Lake Erie was once considered to be strongly contaminated and even “dead” by some environmentalists.
Do the data in Table 13.4 support this idea or are other data needed (e.g., water quality factors for fishers?)
Explain.
No. All of the reported inorganic constituents are reasonably low; however, there may be other indications
13. Recall the relationship between dissolved solids (TDS) and specific conductance (see Introduction to
Exercise 13) and determine the probable specific conductance for water from the
a. Mahoning River? Specific Conductance = TDS / 0.67 =_______ umicromhos/cm
b. Big Four Hollow Creek?
14. From the data in these tables, would you expect most water supplies to be acidic or alkaline?
Alkaline—5 out of the 8 samples are above pH 7.0, but this is a small sample and a small margin.
15. What is the source of water where you are now living? If possible, check with your local water
treatment facility by phone or online, determine its dissolved solids content and record it here.
QUESTIONS 13, PART B
1. Determine the daily load of iron (tons/day) going over Niagara’s Horseshoe Falls (approximate
2. Biodegradable organic matter promotes oxygen demand in streams. What water quality parameter
would be expected to change with increased oxygen demand?
3. Why are silt and clay particles considered to be contaminants?
In water, silt and soil particles produce turbidity, which is a water quality factor (Table 13.1). Turbidity
4. From Table 13.6, what differences in stream-water quality upstream and downstream from a sewage
treatment plant should be expected? Explain.
The treatment processes reduce the BOD, the pathogens, and the nitrates and other organics. There could be
5. a. What is meant by “background” concentrations of chemicals in a watershed?
Natural concentrations of a chemical in water, air, or soil, i.e., without human influence. (Term may be
b. What steps are required to determine the background concentration of chromium in a watershed with a
chrome-plating factory?
Test the water in the main channel and tributaries. Above the source of human influence there should be
6. List three microrganisms that indicate contamination by animal wastes. (In addition to Tables 13.1 and
Table 13.6, see the Introduction to Water Resources and Contamination.)
QUESTIONS 13, PART C
With the aid of information in the Introduction to Part C (and possibly other sources) answer the questions
below.
1. a. What are the sources of bottled water?
b. What factors control the taste of bottled water?
c. Cryptosporidium is a microscopic parasite that lives in human/animal intestines. Cysts of the organism in
the public water supply of Milwaukee, Wisconsin, were eventually responsible for 400,000 cases of illness
and several deaths. Why did the standard chemical disinfectant used in public water systems not kill this
microorganism?
d. Since that time what changes in treatment for public water supplies now remove Cryptosporidium?
Micron filtration and distillation of water by boiling to steam will treat for cysts.
e. Who sets the standards and regulates bottled water?
f. Explain by defining each, the difference between purified and sterilized water.
2. What is the difference between sparkling water and sparkling bottled water?
Sparkling water is sold as a soft drink.
3. Define what is meant by artesian water.
4. a. List all the requirements for bottled water to be labeled mineral water.
b. Does mineral water meet the national Secondary Drinking Water Regulations? Explain.
5. Examine a bottled water label, your own or one available in class or online, and record the following
information on this water. You might need to use an online source, often listed on the bottle, for more
information.
Name of the bottled water:
Company: ________________________________
Size of bottle: mL ______ oz ______ Type of water:
Listed geologic source of water (check one or more):
Groundwater aquifer ______ Spring _____ River_________ Lake ________
Public water system_______ Other _____________
Geographic source of water: ___________
Methods of treatment (if any): ________________________________________________
None:_____ None listed: _______________
6. Check the definitions in the Introduction to this part of the exercise to help answer the following.
a. What is the definition for purified water?
Water that is essentially free of chemicals.
Is the bottle of water described in the question above purified?
What process was used in the purification?
selected.
What is the limit for total dissolved solids (TDS) for purified water?
Has anything been added to the water after purification?
b. What is the definition for sterilized water?
Water that is free from all microbes.
Has the bottle of water described above been sterilized?
What was the process used for sterilization?
7. a. What is the cost per liter for bottled water (give the brand, size, and where purchased [vending
machine, grocery, etc.]? Convert if the bottle is not liter-sized)?
Answers depend on the bottled water selected.
b. How does this compare in price (per liter) with tap water in your city?
(Check with the city or the instructor for tap water cost; 1 U.S. gallon = 3.78 liters in your area.)