Plastic Degradation Study

The goal of our study is to explore how different environmental conditions, specifically UV light exposure and elevated temperatures, affect the degradation of plastics in water over a period of six weeks.

Background Information

Plastic pollution is a major environmental concern. Understanding how plastics break down can help address their long-term impact. Plastics can undergo:

Photodegradation when exposed to UV light.
Thermodegradation under elevated temperatures.

This experiment investigates these processes to determine how they contribute to microplastic formation in aquatic environments.

Hypothesis

The process of thermodegradation will be faster than photodegradation.

Materials

What do we need for this project?

Plastic samples (cut-up pieces of PET bottles or plastic bags)
UV light source (UV lamp or UVB light)
Water containers (glass jars or beakers)
Hot plate for thermodegradation
Thermometer
pH test strips or pH meter
Digital weighing balance
Stopwatch or timer
Safety goggles and gloves
Measuring cylinder
Camera or smartphone (for photos)
Marker (for labeling containers)

Variables

Independent Variables: UV light exposure, elevated temperature.
Dependent Variables: Changes in plastic mass, visible signs of degradation, pH changes in water.
Controlled Variables: Type and size of plastic, volume of water, exposure duration, consistent temperature for thermodegradation.

Procedure

Preparation of Samples

Cut plastic samples into equal-sized pieces (~5 cm x 5 cm).
Measure and record their initial mass.
Fill each container with 200 mL of water.
Place plastic samples into separate labeled containers.

Setting Up Photodegradation

Position plastic samples in transparent containers under a UV light source.
Run the UV light daily for 4 hours to simulate sunlight exposure.
Maintain a consistent distance between the light and each container.
Record visual changes every Tuesday and Thursday.

Setting Up Thermodegradation

Place another set of plastic samples in separate water containers.
Set up the containers on a hot plate at ~50°C.
Heat the water for 4 hours daily, then allow it to cool.
Record the temperature at the start and end of each heating cycle.
Observe and record any changes in the plastic samples.

Before & After

10/30

12/10

Lab Report

Conductivity

Water pH Level

Discussion and Interpretation

Interpret the results in relation to your hypothesis

Our hypothesis was “thermal degradation will be faster than photodegradation”, however the outcome turned out to be the same.

Discuss any unexpected findings and suggest possible reasons for them

We thought that thermal degradation would speed up the degradation of plastic. However, the plastics didn’t have any obvious changes throughout the experiment, and the two samples had similar changes.

Explain how your findings relate to environmental issues such as microplastic pollution and ocean health

As the outcome of plastics’ size and color was similar to what we had observed in the beginning, it shows that plastics take a long time to decompose completely. This shows why microplastic pollution remains a serious issue today and it is nearly impossible to completely solve it.

Consider what your results reveal about the impact of plastic waste in aquatic environments.

The results show that despite providing an environment for plastics to degrade, it is still difficult to degrade those plastics successfully. From this, it reveals that plastic waste in aquatic environments remains an issue.

Conclusion and Future Direction

We found out that plastics are hard to degrade under light and heat. This leads us to think that we can use additional materials such as soil and microorganisms to degrade plastics in faster ways. Additionally, we observed some change in conductivity, which indicates that the plastics are releasing chemicals into the water.