Bio 2106: Environmental Biology

Lab 8: Air Pollution

Lab Requires: 1 week to compete (must have agar plates to complete)

You need to make arrangements to come by my office to pick up you plates if you did not get them already. Please give me 1-2 days notice so I can have them made for you. I can meet you either at RVS (T-H) or RVS (M-W) or leave them for you at either place. Or you can buy them at science stuff (see syllabus)

(Note: This lab has been modified from the ENVIRONMENTAL AIR POLLUTION MONITORING MODULE, provided by Texas Southern University, June 1996.)

Lab Objectives:

1.         Apply the scientific method to various environmental problems:

            a. observation

b. hypothesis formation

c. experimentation

            d. collection of data

            e. data calculations

            f. presentation of data

            g. analysis of data

2.         Examine issues in indoor air quality.

Safety: Wash you hands after you have handled the petri dishes.

Background:

This lab will demonstrate the presence of fungi (molds) and other microorganisms that are present indoors. Most of us are not conscious of these organisms because they are invisible. The invisible organisms are universally present in air. More attention is focused on their presence in our air due to environmental health concerns about "indoor air". Many people are concerned that inside air can contain unusually high numbers of molds and microorganisms, which may have a harmful effect upon people who are sensitive to them. Air particulates can cause or contribute to respiratory diseases and other illnesses. There has been a increased awareness of indoor air quality as more and more homes in the Austin area have been identified as having "sick building syndrome". Molds that produce neurotoxins have been found in numerous homes in Austin and the surrounding areas. Once identified, people must move out of their homes immediately or suffer neurological damage. The cost and ability to clean up these homes and buildings vary. In some instances, internal walls, carpets and floors must be replaced. A friend of mine just got the estimate to repair their home- $60,000. In other cases (such as recent one in Dripping Springs) the entire 2 million-dollar home had to be demolished.

There are 2 major types of air pollution: solid particles and gases. This lab focuses on the solid particles in the air that come from natural sources, such as pollen from flowers or microorganisms such as mold spores. Other solid particles arise from human activities such as burning coal, burning garbage in combustors or incinerators, or burning oil in furnaces.

Yeast, molds, and mushrooms are organisms that are found in Kingdom Fungi. They live on other plants and animals, absorbing nutrients by decomposition. A fungus reproduces by forming reproductive cells called spores. The spores are released into the air and settle on an acceptable surface (a proper medium), begin to grow, and utilize the host’s nutrients.

Humid areas, such as Austin and Houston, encourage the growth of molds. As a result, our air is full of such particles even though we cannot see them. We can take precautionary measures to reduce their accumulation only when we are environmentally aware of their presence.

 

 

 

Materials:

5 petri dishes with nutrient agar

Procedure, Part 1:

1.         Individuals will select locations for sampling. Choose 4 indoor and one outdoor as your control. Try to think of a variety of different places- both public and private.

A.        _______________________________

B.        _______________________________

C.        _______________________________

D.        _______________________________

E.        (outside)________________________

 

 

 

 

2.         Label the bottom of each Petri dish containing nutrient agar with the following:

                        date

                        location where Petri dish will be placed

  1. Carry your Petri dishes to the chosen locations. Record the time you open each dish in the space provided. Expose the Petri dish to the air for exactly one hour.

 

            Location                                 Time Petri dish uncovered

            _________________                      ________________

            _________________                      ________________

            _________________                      ________________

            ________________                        __________________

            ________________                        __________________

 

  1. Cover and place the exposed Petri dishes upside down in a warm draft free place (temperatures above 25oC are best if possible) for 72 hours. Since you are not incubating the organisms, you may not get bacteria to grow, or they may be taken over by mold. But molds should grow just fine.
  2. Before you examine your plates, write a hypothesis which indicates which agar plates you expect to have the most mold growth and why. For example, if I places plate A in the highschool locker room., plate B in the post office, plate C in my kitchen and plate D in my living room. I might write:

I expect plate A to have the highest number of mold colonies because I placed it in a place with lots of people, and warm, moist conditions conducive to mold growth. Plate C will have the next highest number of colonies because…. And so on.

HYPOTHESIS

 

 

 

 

 

 

 

 

 

 

 

 

5.         Check the dishes for growth. Count the number of colonies and observe the physical appearance of the colonies: shape, color, wet/dry appearance. Record the results in the data chart.

 

 

LAB REPORT – Air Quality

Name ________________________

1.         Data Table

 

LOCATION

# OF COLONIES

COMPARISON TO OUTSIDE PLATE

A

 

 

 

B

 

 

 

C

 

 

 

D

 

 

 

E

(outside)

 

1.0

 

AVERAGE

 

 

 

 

 

 

Note: use you outside plate as your control. If the outside plate had 6 colonies, an inside plate with 6 colonies would have an index number of 1 (6/6 = 1.0)

 

 

2.         Which indoor location had the most mold and microorganisms? Why?

 

 

 

 

 

 

3.         Which indoor location had the least? Why?

 

 

 

 

 

 

4.         How did the outdoor air compare to the average indoor air?

 

 

 

 

 

5.         What do the results of this lab indicate about indoor air quality?

Part 2. Learning more about indoor air pollution

Go to the web and look up indoor air quality. One good site is EPA Indoor Air, but there are a variety of others you may wish to examine.

  1. Write a paragraph describing all the possible sources of air pollution. There are at least 5-6 different types- so make sure you visit a site with plenty of information. Please list your web site.

 

 

 

 

 

 

 

 

 

 

 

2) Pick one of the sources described above, and investigate it in more detail. Find out a) how this source of pollution gets into homes and offices, b) what types of buildings are most susceptible c) what are the warning indicators for that type of pollution and d) how does one clean up the pollution, once it has been detected.

Make sure to list your web site.