Water Quality and Contamina on
x
Usable water
x
Ground water contaminates
x
Ground water
x
Water treatment
x
Surface water
x
Drinking water quality
Figure 1: At any given moment, 97% of the planet’s water is in oceans. Only a small fraction of
the remaining freshwater is usable by humans, underscoring the importance of treating our water supply with care.
It is no secret that water is one of the most valuable resources on Earth. Every plant and animal requires water to survive, not only for drinking, but also for food production, shelter creation, and many other necessities.
Water has also played a major role in transforming the earth’s surface into the varied topography we see today.
While more than 70% of our planet is covered in water, only a small percentage of this water is usable freshwater. The other 99% of water is composed primarily of salt water, with a small percentage being composed
22
of glaciers. Due to the high costs involved in transforming salt water into freshwater, the earth’s population
survives off the less than 1% of freshwater available. Humans obtain freshwater from either surface water or
groundwater.
Surface water is the water that collects on the ground as a result of precipitation. The water that does not
evaporate back into the atmosphere or infiltrate into the ground is typically collected in rivers, lakes, reservoirs, and other bodies of water, making it easily accessible.
PrecipitaƟon
PrecipitaƟon
PrecipitaƟon
TranspiraƟon
Cloud formaƟon
EvaporaƟon
EvaporaƟon
Groundwater
Figure 2: Water is a renewable source, purified and
delivered across the planet by the hydrological cycle.
Groundwater, on the other hand, is located underneath the ground. This water is stored in pores, fractures,
and other spaces within the soil and rock underneath the surface. Precipitation, along with snowmelt, infiltrates through the ground and accumulates in available underground spaces.
Aquifers are areas in which water collects in sand, gravel, or permeable rock from which it can be extracted
for usable freshwater. The depth of aquifers varies from less than 50 feet to over 1,500 feet below the surface. The water within an aquifer typically does not flow through, as it would through a river or stream, but instead soaks into the underground material, similar to a sponge. As aquifers are depleted by human use, they
are also recharged from precipitation seeping into the ground and restoring the water level. However, many
times the recharge of the aquifers does not equal the amount of water that has been extracted. If that cycle
continues, the aquifer will eventually dry up and will no longer be a viable source of groundwater.
23
Water is the only substance
that is found naturally in
three forms: solid, liquid,
and gas
If the entire world’s supply
of water could fit into a onegallon jug, the fresh water
available to use would equal
less than one tablespoon
Approximately 66% of the
human body consists of water - it exists within every
organ and is essential for its
function
While the water that precipitates in the form of rain is relatively pure, it does not take long for it to pick up contaminants. There are natural, animal, and human-made sources of water pollutants. They can travel freely
from one location to another via streams, rivers, and even groundwater. Pollutants can also travel from land
or air into the water. Groundwater contamination most often occurs when human-made products, such as motor oil, gasoline, acidic chemicals, and other substances, leak into aquifers and other groundwater storage
areas. The most common source of contaminants come from leaking storage tanks, poorly maintained landfills, septic tanks, hazardous waste sites, and the common use of chemicals, such as pesticides and road
salts.
The dangers of consuming contaminated water are
high. Many deadly diseases, poisons, and toxins can
reside in contaminated water supplies, severely affecting the health of those who drink the water. It is also
believed that an increased risk of cancer may result
from ingesting contaminated groundwater.
With the many contaminants that can infiltrate our water supply, it is crucial that there be a thorough water
treatment plan in place to purify the water and make it
drinkable. While each municipality has its own water
treatment facility, the process is much the same at
each location.
Figure 3: Sedimentation tanks, such as those shown
above, are used to settle the sludge and remove oils
and fats in sewage. This step can remove a good portion of the biological oxygen demand from the sewage, a key step before progressing with the treatments and eventually releasing into the ground or
The process begins with aeration, in which air is added body of water.
to the water to let trapped gases escape while increasing the amount of oxygen within the water. The next
step is called coagulation or flocculation, in which chemicals, such as filter alum, are added to the incoming
24
water and then stirred vigorously in a powerful mixer. The alum causes
compounds, such as carbonates and hydroxides, to form tiny, sticky clumps
called floc that attract dirt and other small particles. When the sticky clumps
combine with the dirt, they become heavy and sink to the bottom. In the next
step, known as sedimentation, the heavy particles that sank to the bottom
during coagulation are separated out and the remaining water is sent on to
filtration. During filtration, the water passes through filters made of layers of
sand, charcoal, gravel and pebbles that help filter out the smaller particles
that have passed through until this point. The last step is called disinfection,
in which chlorine and/or other disinfectants are added to kill any bacteria
that may still be in the water. At this point, the water is stored until it is distributed through various pipes to city residents and businesses.
Figure 4: Fresh water is essential to humans and other landbased life. Contaminated water
After the water goes through the treatment process, it must also pass the must be treated before it can be
guidelines stated in the Safe Drinking Water Act, in which various compo- released into the water supply.
nents are tested to ensure that the quality of the water is sufficient for drinking. There are currently over 65 contaminants that must be monitored and maintained on a regular basis to
keep local drinking water safe for the public. Some of these chemical regulations include lead, chromium,
selenium, and arsenic. Other components, such as smell, color, pH, and metals, are also monitored to ensure
residents are provided clean and safe drinking water.
25
Bottled water is a billion dollar industry in the United States. Still, few people know the health benefits, if any,
that come from drinking bottled water as opposed to tap water. This experiment will look at the levels of various different chemical compounds in both tap and bottled water to determine if there are health benefits in
drinking bottled water.
Dasani® bottled water
(1) 100 mL Graduated Cylinder
Fiji® bottled water
Permanent marker
Jiffy Juice
Stopwatch
Ammonia test strips
Parafilm®
Chloride test strips
Pipettes
4 in 1 test strips
(3) Foil packets of reducing powder
Phosphate test strips
*Tap water
Iron test strips
(3) 250 mL Beakers
*You must provide
(3) 100 mL Beakers
1. Before beginning, record your hypothesis in post-lab question 1 at the end of this procedure. Be sure to
indicate which water source you believe will be the dirtiest and which water source will be the cleanest.
2. Label three 250 mL beakers Tap Water, Dasani®, and Fiji®. Pour 100 mL of each type of water into the
corresponding beakers.
3. Locate the ammonia test strips. Begin by placing a test strip into the Tap Water sample and vigorously
moving the strip up and down in the water for 30 seconds, making sure that the pads on the test strip are
always submerged.
26
4. Remove the test strip from the water and shake off the excess water.
5. Hold the test strip level with the pad side up for 30 seconds.
6. Read the results by turning the test strip so the pads are facing away from you. Compare the color of the
small pad to the color chart at the end of the lab. Record your results in Table 1.
7. Repeat the procedure for both Dasani® and Fiji|® bottled water. Record your results for both in Table 1.
8. Locate the chloride test strips. Begin by immersing all the reaction zones (“the pads”) of a test strip in the
Tap Water sample for 1 second.
9. Shake off the excess liquid from the test strip. After 1 minute, determine which color row the test strip
most noticeably coincides with on the color chart at the end of the lab. Record your results in Table 2.
10. Repeat the procedure for both Dasani® and Fiji® bottled water. Record your results for both in Table 2.
11. Locate the 4 in 1 test strips. Begin by dipping a test strip in the Tap Water for 5 seconds with a gentle
back and forth motion.
12. Remove the test strip from the water and shake once, briskly, to remove the excess water.
13. Wait 20 seconds and use the color chart at the end of this lab to match the test strip to the Total Alkalinity, Total Chlorine, and Total Hardness on the color chart. Be sure to do all of the readings within seconds
of each other. Record your results in Table 3.
Note: You will not be using the pH reading obtained from the 4 in 1 test strips. The pH will be
determined at the end of this experiment using a different method.
14. Repeat the procedure for both Dasani® and Fiji® bottled water. Record your results for both in Table 3.
15. Locate the phosphate test strips. Begin by dipping a test strip into the Tap Water for 5 seconds.
16. Remove the test strip from the water and hold it horizontally with the pad side up for 45 seconds. Do not
shake the excess water from the test strip.
27
17. Compare the results on the pad of the test strip to the color chart at the end of this lab. Record your results in Table 4.
18. Repeat the procedure for both Dasani® and Fiji® bottled water. Record your results for both in Table 4.
19. Now, label the three 100 mL beakers Tap Water, Dasani®, and Fiji®. Use the 100 mL graduated cylinder
to measure 30 mL of the Tap Water from the 250 mL beaker. Pour the Tap Water into the 100 mL beaker.
Repeat these steps for the Dasani® and Fiji® bottled water.
20. Beginning with the Tap Water, open one foil packet of reducing powder and add it to the 100 mL beaker.
Cover the beaker with a piece of Parafilm® and shake the beaker vigorously for 15 seconds.
21. Locate the iron test strips. Remove the Parafilm® and dip the test pad of an iron test strip into the Tap Water sample, rapidly moving it back and forth under the water for 5 seconds.
22. Remove the strip and shake the excess water off. After 10 seconds, compare the test pad to the color
chart at the end of this lab. If the color falls between two colors on the color chart, estimate your result.
Record your results in Table 5.
23. Repeat the procedure for both Dasani® and Fiji® bottled water. Record your results for both in Table 5.
24. Use your 100 mL graduated cylinder to measure and remove 45 mL of the Tap Water from the 250 mL
beaker. Discard this water. Your 250 mL beaker should now contain 25 mL of Tap Water. Repeat these
step with the Dasani® and Fiji® bottled water.
25. Use a pipette to add 5 mL of Jiffy Juice to the Tap Water. Mix gently with the pipette or by swirling the liquid.
26. Compare the color of the Tap Water to the pH chart in the key. Record the pH in Table 6.
27. Repeat the procedure with both the Dasani® and Fiji® bottled water and record your results in Table 6
28
0
10
30
60
100
200
400
Ammonia (mg/L)
0
Chloride (mg/L)
500
1000
1500
2000
≥3000
4-in-1 Test Strip:
*Note there are 4 pads on this test strip. From top to bottom (with the bottom of the strip being the handle),
the pads are: pH, Chlorine, Alkalinity, and Hardness. Remember that the pH is not to be measured using the
strip.
pH
Chlor.
Hard.
Alk.
0
0.2
1.0
4.0
10.0
0
40
80
120
180
Total Chlorine (mg/L)
240
500
Total Alkalinity (mg/L)
0
50
120
250
425
1000
Total Hardness (mg/L)
Soft
Hard
Very Hard
29
0
10
25
50
100
Phosphate (ppm)
0
0.15 0.3
0.6
1
2
5
Total Iron (ppm)
1-2
pH
30
3
4
5
6
7
8
9
10 11-12
Alternative Energy Options
As you know, our world is heavily dependent on fossil fuels for meeting our energy needs. In
Chapter 6 of Contemporary Environmental Issues, you have read that there is concern about the
possibility of reaching a peak in oil production, and even coal and natural gas will eventually run
out. (Next week, in Chapter 7 of the textbook, we will read about an even more pressing reason
for no longer relying on fossil fuels: global climate change.) Chapter 8 of Contemporary
Environmental Issues introduces a variety of possible alternative energy sources, including
nuclear power and many renewable options like wind power and solar energy.
Next week, you will be participating in a collaborative project aimed at developing an alternative
energy plan for a particular community – the details of which won’t be revealed until then. For
now, let’s all pool our research into what possible energy choices might be able to help us move
away from fossil fuels.
In your main post this week, please
•
•
•
Identify two alternatives to fossil fuels that are currently available.
Discuss the barriers that keep these alternatives from replacing coal, oil, and natural gas as our
primary means of energy.
Discuss the role that government plays in ensuring a transition to these renewable alternatives
in a post-carbon world.
Be creative here – the ideas you explore now might become the building blocks for next week’s
sustainable energy plan.
Your initial post should be at least 250 words in length. Utilize at least two scholarly or reputable
resources and your textbook to support your claims, using the Scholarly, Peer Reviewed, and
Other Credible Sources (Links to an external site.)Links to an external site. document for
guidance. Cite your sources in APA style (Links to an external site.)Links to an external site., as
outlined in Ashford Writing Center (Links to an external site.)Links to an external site.. Quoted
text should constitute no more than ten percent of your post.
Purchase answer to see full
attachment