Virtual Lab-water Quality 124j6u

Name Anthony Medeiros Class 1st Date 11-20-14 Virtual Lab: When Is Water Safe To Drink? Suppose you were hiking along a stream or lake and became very thirsty. Do you think it would be safe to drink the water? In many cases, it wouldn't. Each source of fresh water on or beneath Earth's surface is affected by contaminants. Though the sources of these contaminants are varied, all can make water unfit to drink if they are allowed to increase beyond safe limits.

Go to the website: http://www.glencoe.com/sites/common_assets/science/virtual_labs/CT04/CT04.html In this Virtual Lab, you will test a variety of water samples. Then you will determine how to treat the water samples to make them safe to drink Look at the screen to your left, READ and find out about the most common types of water contaminants. Describe what they are and how they might affect water quality. Acidity: The pH scale measures acidity and acidity is the measure of acid and other substances in the water. Acidity affects water quality by magnifying other contaminants in the water. .

Bacteria: Bacteria are microorganisms found in water. Bacteria decreases water quality and increases risk of contracting a waterborne disease.

Metals: There are many types of metals found in water, and certain metals can contaminate the water. .

Nitrates: Nitrates are a form of oxygen that is found in animal waste. Nitrates pose little threat to humans but an overabundance of it can kill aquatic creatures.

Pesticides: Pesticides are chemicals used to kill certain unwanted insects and animals. Pesticides ruin water quality and can cause a number of health problems.

Objectives: 1. ·Define types of water contaminants. 2. ·Determine which types of contaminants are common to lake water, city water, well water, rural water and mountain water. 3. ·Identify treatments that remove contaminants from drinking water. Procedure: 1. Click the right and left arrows to select a body of water to analyze. 2. Click Test to test the water sample. 3. Look at the results of the water analysis. Identify the “Safe Range” for each category and record this in the data table. 4. Identify which contaminants exceed the safe range. 5. Click the tabs to find information on how to treat each contaminant. 6. Enter the contaminant and treatment information in your data table. 7. Click Go To Treatment to go to the treatment screen. 8. Use the information in the table and click the wheels on the valves to add chemicals or additives to the water sample. 9. Click the Treatment Switch to start treating the water. The Safe/Unsafe Sign will indicate whether the water is safe to drink. 10. If the water is safe to drink, use Return to Lab to go to the lab screen and test another water sample. 11. If the water is unsafe to drink, check your information and treat the water sample again.

12. When you have tested and treated all the water samples, use your completed table to complete the analysis questions.

Analysis 1.

What contaminants were found in the surface water samples? What contaminants were found in the groundwater samples? Surface water has more nitrates, pesticides, and bacteria, while groundwater has more metals.

2.

Why might groundwater and surface water have different contaminants? They might have different contaminants because there might be different bacteria or chemicals on the surface or vice versa.

3. Generally, farmers do not farm on the sides of mountains or in remote areas. Industries also do not build factories in these areas. These areas are usually not highly populated by people. What might explain the high nitrate level in the mountain water in this activity? The high nitrate level might be due to the surface runoff from the slopes of the mountain, leading to a lot more runoff there.

4. What is pH level, what are its characteristics, and how does it contribute to pollution? What chemicals are used in treating low pH levels? PH is the measure of acidity of a substance, and it magnifies the effect that other contaminants may have. Sodium hydroxide can treat this.

Critical Thinking-Please read this carefully! Water in an old building tested recently, showed high copper and iron content, and low pH levels. A water reading taken 20 years before, showed low pH levels and only minimal traces of copper and iron. If none of the new buildings on the same street showed signs of metallic contaminants, but all reported lower than normal pH readings, how might these readings be explained?

Sample

Acidity (pH)

Metals (mg/L)

Coliform Bacteria (ml) 0 per 100 mL

Pesticides/Herbicides (mg/L)

Nitrates

Type of Contamination

Treatment Performed

Safe Range

6.58.5

City

4

Less than 1.3 mg/L .0006 mg\L (copper)

Less than .04 mg/L

None

None

13/100 mL

.00001 mg\L carbofuran

Less than 10 mg/L .8 mg\L

Acidity and Bacteria

Sodium Hydroxide and Chlorine

Lake

7

.6 mg\L (iron)

33/100 mL

.0008 mg\L carbofuran

.6 mg\L

Bacteria

Chlorine

Mountain

6.8

.006 mg\L (iron)

0/100 mL

.0001 mg\L carbofuran

12.4 mg\L

Nitrates

Activated Carbon

Rural

7

.0027 mg\L (copper)

0/100 mL

.08 mg\L carbofuran

6.7 mg\L

Pesticides/ Herbicides

Activated Carbon

Well

8.2

1.44 mg\L (copper)

0/100 mL

.0004 mg\L carbofuran

.6 mg\L

Metals

Chlorine then Zinc Orthophosphates