Name Period Date
TESTING POLLUTION IN TAP WATER
Background
Water is an essential resource for humans. It is used for almost every activity in life and is required for life itself. In fact, water is the main component I cells and it composed up to 70-
90% of the weight of living organisms. Water is needed for agricultural and industrial use, drinking, transportation, and recreation. Water often seems to be available in almost endless supply, but as populations rise and our world becomes increasingly industrialized, more and more water is being used. With this extensive use of water, a problem arises------the water becomes polluted and contaminated. The pollution leads to a strain on the water’s ability to recycle and cleanse itself of contaminants. It is now estimated that over one billion people are unable to obtain adequate drinking water. The amount of water available, its distribution, and its quality are critical issues that continue to affect all life. An increasing awareness of the need to monitor the quality of water and to locate the sources of pollution is becoming more prevalent in today’s society.
Roughly, half the population of the US depends on underground aquifers as a source of drinking water. Aquifers are water-bearing, porous layers of gravel, sand, and rock below the Earth’s surface that contain and hold groundwater. The overall quality of water found in underground aquifers is being increasingly threatened by both pollution and overuse.
Pollution of aquifers is a major threat to the quality of drinking water due to the fact that it generally takes hundred, up to thousands of years for deep aquifers to totally replenish their water supply.
As polluted water enters the groundwater supply, the concentrations of certain pollutants may alter drinking water’s purity. If the concentration of a pollutant reaches a certain level, the water could become hazardous to human health. The following is a list of some common pollution indicators and how they affect our tap water:
Chlorine – Chlorine is not naturally found in water. It is added to public water systems and swimming pools as a bactericide. Chlorine in drinking water is generally maintained under 0.75 parts per million (ppm).

Total Hardness – Hardness is a measure of the amount of calcium and magnesium in water. Both calcium and magnesium may originate from soils or from commercial and industrial wastes. Water with a low level of hardness is referred to as soft water, while water with a high level of calcium and magnesium is referred to as hard water. The main effects of hard water are on pipes and appliances, and may decrease the effectiveness of soaps and laundry detergents. Water with a range of 0-60 ppm is considered soft, 60-120 ppm is medium hard, 120-180 is hard, and 180 ppm and above is extremely hard.
Iron – Iron, in small amounts, is an essential nutrient to humans and other organisms. It is present in water from natural sources such as rocks and soils and it is also found in water due to industrial waste and the corrosion of iron pipes. When the concentration of iron is above 0.1 ppm, it will condense as iron oxides, such as rust when it comes in contact with air. Iron oxides will stain laundry, plumbing fixtures, and silverware. It will also cause food and drinks to taste and look peculiar. Iron concentrations in drinking water should not exceed 0.3 ppm.
Copper – Copper is present in water from sewage or industrial waste. It is also added to reservoirs and ponds to control the amount of aquatic vegetation. Even though copper is essential in small amounts to the human body, excessive amounts can result in liver damage. If concentrations of cooper are above 1 ppm, drinking water may taste bitter.
Normally, the amount of copper in drinking water is below 0.03 ppm, but it may reach up to
0.6 ppm in certain places.
pH – The pH scale ranges from 0 to 14 with 7 being neutral. Values lower than 7 are acidic and higher than 7 are basic. Although ponds and other aquatic environments may range in pH from 6.5 to 8.2, drinking water should be around 7.

Problem
What types of pollutants are in our water? How do these pollutants affect us?
Materials
Chlorine DPD #4R TesTab, Total hardness test strip, Iron TesTab, Copper HR TesTab, pH TesTab, comparison charts, test tubes, tap water
Procedure
THESE TESTS CAN BE DONE IN ANY ORDER, EXCEPT FOR THE IRON TEST. DO THE IRON
TEST FIRST, SECOND, OR THIRD SINCE YOU HAVE TO WAIT 5 MINUTES FOR THIS TEST.
Part 1 – Chlorine Test
1.
Fill a water sample tube to the 5 mL line with the tap water sample.
2.
Add one chlorine DPD tablet to the water.
3.
Cap the tube and mix the solution until the tablet has dissolved.
4.
Compare the color of the sample to the chlorine color comparison chart. Record the findings as parts per million in the data table.
5.
Pour the reacted water sample into the glass disposal beaker. Rinse the sample tube in the plastic water bucket.
Part 2 – Hardness Test
1.
Fill a water sample tube to the 14 mL line with the tap water sample.
2.
Dip the hardness test strip into the water.
3.
Compare the color of the test strip to the hardness color comparison chart. Record the findings as parts per million in the data table.
4.
Pour the reacted water sample into the glass disposal beaker. Rinse the sample tube in the plastic water bucket.
Part 3 – Iron Test
1.
Fill a water sample tube to the 5 mL line with the tap water sample.
2.
Add one iron test tablet to the water.
3.
Cap the tube and mix the solution until the tablet has dissolved.
4.
Wait for 5 minutes.
5.
Compare the color of the sample to the iron color comparison chart. Record the findings as parts per million in the data table.
6.
Pour the reacted water sample into the glass disposal beaker. Rinse the sample tube in the plastic water bucket.
Part 4 – Copper Test
1.
Fill a water sample tube to the 10 mL line with the tap water sample.
2.
Add one copper HR tablet to the water.
3.
Cap the tube and mix the solution until the tablet has dissolved.
4.
Compare the color of the sample to the copper color comparison chart. Record the findings as parts per million in the data table.
5.
Pour the reacted water sample into the glass disposal beaker. Rinse the sample tube in the plastic water bucket.
Part 5 – pH Test
1.
Fill a water sample tube to the 10 mL line with the tap water sample.
2.
Add one pH wide range test tablet to the water.
3.
Cap the tube and mix the solution until the tablet has dissolved.
4.
Compare the color of the sample to the pH color comparison chart. Record the findings as parts per million in the data table.
5.
Pour the reacted water sample into the glass disposal beaker. Rinse the sample tube in the plastic water bucket.

Results
Data Table: make sure the data table is complete and follows data table rules.
Test Results (parts per million) Factor
Chlorine
Hardness
Iron
Copper pH
Questions
1.
What percentage of living things is composed of water?
2.
What is an aquifer?
3.
How many do not have adequate drinking water?
4.
What effect can high concentrations of copper have on the human body?
5.
What 2 elements cause hard water stains?
6.
Approximately, what pH do we want our tap water to be?
7.
Why is chlorine added to water sources?
8.
Between chlorine, iron, and copper, which one is naturally found in water?
9.
Which pollutant(s) affects your tap water the most?
10.
Overall, would you classify your tap water as polluted or non-polluted?