5.3 Consider This:  Finding Out About Bottled Water

If you search for "bottled water" on the Web, you will get over a million "hits." Select two sites to explore, one provided by a supplier and the other provided as a source of consumer information. The former may flood you with statistics about the benefits of bottled water; the latter may raise questions, such as "Is bottled water safer?" or "Is it worth the cost?" For each site, list the title, author, URL, and two things that you learned about water from the site.

5.4 Consider This:  Your Drinking Water Source

Do you know where your drinking water comes from? You can find out by using the Safe Drinking Water Information System (SDWIS) of the EPA Office of Ground Water and Drinking Water. Search for the source of your home’s drinking water by entering the geographic area in which you live. Then answer these questions.

1. What is the name of the water system that services your home?
2. What is the primary water source for that system?
3. What information is given about the quality of that system’s drinking water?

5.5 Consider This:  Water Quality in Your State

Each state has different concerns about its surface and ground water.

1. Draw up a list of the issues in your state. For example, you might mention agricultural runoff, leaking storage tanks, or pollution from other human activities.
2. Read the state fact sheet prepared by the Ground Water Protection Council. What does the sheet say about the surface and ground water quality in your state?
3. The EPA notes that some states have lakes, rivers, and streams that support no aquatic life. What percent of the surface water in your state falls in this category?

Note: You may also wish to consult the Water Atlas of the EPA. This site has links to more maps, as well as information about water uses, water resources and threats to the health of U.S. waters.

5.21 Consider This:  Three-Dimensional Representations of Molecules

Three-dimensional representations of molecules can be viewed on the Web using CHIME, a free plug-in that you can download and install. Here are three-dimensional representations of ethanol, ethylene glycol, and sucrose. Use these molecular representations to identify the places in each compound where hydrogen bonding occurs. Has your mental picture of these molecules changed after seeing these 3-D representations? Explain.

5.23 Consider This:  A Drink of Water -- What Is In It?

Table 5.10 is merely a starting point for the wealth of information available about six possible pollutants in drinking water. At the EPA Office of Ground Water and Drinking Water, you can access a consumer fact sheet on each of these pollutants, as well as dozens more. You also can find a technical version of each fact sheet (recommended) at the end of each list of contaminants. Look up a pollutant listed in Table 5.10 to find out how the pollutant gets into the water supply and how you would know if it were in your drinking water. Is your state listed as one of the top states that releases the contaminant?

Note: Arsenic, cadmium, lead, chromium, mercury, and nitrate/nitrite ions are found under the section on Inorganic Contaminants. Benzene is listed under Volatile Organic Contaminants. No trihalomethane such as CHCl₃ currently is listed, but you can find a variety of other chlorinated compounds found in water, such as CCl₄ and CH₂Cl₂.

5.24 Consider This:  MTBE in Ground Water

The gasoline additive MTBE was discussed in Chapter 4 as one of the mandated oxygenates in certain metropolitan areas to reduce air pollution. Concern about the accumulation of MTBE in surface and groundwater, with the potential to compromise the quality of drinking water supplies, has led to some changes in policy in some areas of the U.S. Find the current status of the use of MTBE. Consult the EPA for a fact sheet or for recommendations, the USGS for their Toxic Substances Hydrology Program or use other resources suggested by your instructor.

5.25 Consider This:  Cryptosporidium

As of January 1, 2002, EPA’s surface water treatment rules require systems using surface water or groundwater under the direct influence of surface water to remove or deactivate 99% of Cryptosporidium.

1. What is Cryptosporidium?
2. What are the sources of this contaminant in drinking water?
3. What are the potential health effects from drinking water contaminated with cryptosporidium?
4. Why was this rule issued in 2000, but not required until 2002?

5.27 Consider This:  Purifying Water Away From Home

How can you purify water when you are hiking? Use the resources of the Web to explore some of the possibilities. What are the relative costs and effectiveness of these alternatives? Are any of the methods similar to those used to purify municipal water supplies? Why or why not?

5.29 Consider This:  Water Hardness in Your Area

Find information about the water hardness in your part of the country.

1. How "hard" or "soft" is the water in your area? Were you surprised at the answer?
2. Assuming that water softening is necessary, what are the options for it in your area?
3. Are any health risks associated with using hard water? With using soft water?
4. Has EPA set standards for any of the ions responsible for hard water? Explain?

Note: One source of data is your local Annual Water Quality Report, many of which are published on the web.

5.30 Consider This:  Lead, Mercury, or Cadmium in Your Drinking Water

Find out whether lead, mercury, or cadmium ions are a significant problem in drinking water where you live or on your campus. You might begin with the map of local drinking water systems provided by EPA’s Office of Ground Water and Drinking Water. Your local water utility company or state drinking water program should be able to provide information as well.

1. If these ions are present, what are some likely sources of them?
2. Are the concentrations of these ions above the MCLG or MCL?

5.32 Consider This:  Regulating Arsenic in Drinking Water

Another toxic metal that can find its way into public water supplies is arsenic. Early in January 2001, the Clinton administration issued a 10-ppb standard for arsenic in drinking water, replacing the standard of 50 ppb set in 1962. The Bush administration soon after recalled the rule before it could take effect, thus reverting to the 50 ppb standard, a controversial decision.

1. What was the reasoning behind each administration’s decision?
2. What has been the response to each administration’s decision?
3. Determine whether the 50 ppb is still the standard for arsenic.