Environmental Effects of Biodegradability on Plastic Bags, Paper Bags, and Newspaper

Note:This experiment requires a time period of at least 3 months.

Purpose

To test several types of plastic bags in different environments to determine if and how fast they decompose in comparison to paper bags and newspaper in the same environments.

Materials Needed

• 10 biodegradable plastic bags (use two different brands)
• 10 nonbiodegradable plastic bags (use two different brands)
• 3 nets (plastic or cotton)
• wire or string
• 6 wooden posts
• 5 brown paper bags
• 5 pages of newspaper
• mulch pile—approximately 4 feet (120 cm) high (consisting of grass clippings and leaves with rotting vegetable matter, fertilizer, and compost starter culture) in a foot-(2-m-) diameter ring made of wire fencing material
• tap water
• leaf pile—approximately 3 feet (1 m) high
• 10 plastic containers (approximately ½ gallon (2 liters) each)
• saltwater (15% by volume)

Experiment

The biodegradability of several plastic bags, brown paper bags, and newspaper will be tested in different environmental conditions: in direct sunlight, in a mulch pile (to simulate an active landfill), in a leaf pile (to simulate a dry landfill), in tap water (to simulate a lake), and in saltwater (to simulate an ocean).

Procedure

1. Fold and secure two types of biodegradable plastic bags and two types of nonbiodegradable plastic bags on top of a net with wire or string. Tie a wooden post at each end of the net and place each post into the ground, leaving the plastic bags exposed to the sun. Do the same with one paper bag and a page of newspaper.
2. Repeat step 1 by placing the same types of bags in the middle of a mulch pile. Wet the pile thoroughly with water.
3. Repeat step 1 by placing the same types of bags in the middle of the leaf pile.
4. Place two types of biodegradable plastic bags, two types of nonbiodegradable plastic bags, one paper bag, and one page of newspaper into five separate containers of tap water. Then, place the same types of materials into separate containers of 15% (by volume) saltwater.
5. Allow all the materials to stay in their environments for three months or longer. Record the changes that occurred to the plastic bags, paper bags, and newspapers in the different environments upon removal.

Results

1. Did any of the materials decompose? If so, which materials decomposed most thoroughly?
2. Was the rate of degradation greatest in the sunlight, mulch pile, leaf pile, tap water, or saltwater environments?
3. Did the plastic bags that were advertised as biodegradable appear any different from the nonbiodegradable bags?

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