The Plastic Breakdown

As plastic pollution continues to spiral out of control and have an alarming impact on the environment, the need for hard data about the damage caused by plastic pollution is more critical than ever.

As plastic pollution continues to spiral out of control and have an alarming impact on the environment, the need for hard data about the damage caused by plastic pollution is more critical than ever. Over the last half-century, plastic production has increased at an astonishing rate due to its low cost to manufacture and its ease of use compared to other materials, such as glass. While plastic is indeed a pollutant, the full extent of the damage it causes is unknown. Marine animals, particularly fish, sea turtles and seabirds, are being seriously injured and often die when they consume or become entangled in plastic debris. Not only does plastic damage marine ecology, but its byproducts are extremely harmful.

Over time plastic begins to degrade, becoming brittle and breaking down into smaller plastic pieces called microplastics. Microplastics may even be more damaging than whole plastics because of the way they affect the food web. Organisms like shrimp and plankton that filter feed through the water accumulate microplastics because they cannot digest them. These organisms as a result are nutritionally deprived, suffer obvious physical damage and transfer these deleterious plastics up the food chain. As microplastics in marine ecosystems become increasingly prevalent, organisms essential to the ecosystem will die out and the ecosystem will fail.

Despite public assertions that plastic bags, straws and other materials take 500 years to decompose fully, there is no scientific evidence to support these claims. In his research, Col. John Weinstein, Ph.D., chair of the Biology Department, found that there were more than seven tons of plastic debris in Charleston harbor. From Weinstein’s research, I do not believe that it takes anywhere close to 500 years for straws, plastic bags and Styrofoam cups to degrade because in previous experiments conducted in his lab, he recorded the emission of microplastics—the first step in the overall breakdown of plastics—in materials that had only been exposed to salt marsh conditions for a couple of weeks.

In my research, which is taking place over a 14-month period, I have introduced plastic straws, bags and Styrofoam cups to the marsh. Fifty samples of each plastic item were attached to wooden planks which were anchored in the marsh behind the rifle range on campus. The materials are submerged for 12 hours in the salt water, followed by 12 hours of direct sunlight. Every four weeks, I return to the site to collect three samples of each material to measure the rate of breakdown. I took my first sample two weeks after the project’s deployment in February and every four weeks thereafter for a total of 16 collections. During each collection, a sample from each of the plastics is placed in a microplastic emission chamber where it spins for a six-hour period. To decrease the risk of outliers, this process is repeated three times. Conducting this research in the marsh is important because there are tide cycles in the marsh, and the plastic samples found there have spent periods fully emerged in saltwater and, alternately, exposed to direct sunlight. Both cycles contribute to the breakdown of plastic.

The goal of my research is to gather quantitative results about the time plastics actually take to break down so that public policy and debate can focus on plastics and the impact plastic pollution has on marine life. With renewed awareness, more research will be conducted, with a long-term goal of solving the environmental issues that plastics are causing.

Cadet Nicolás Trocha is a defensive back for the Bulldogs and a senior biology major from Greenville. His plastic research is an interdisciplinary project that he is conducting through the Honors Program. A member of Phi Kappa Phi, the academic honors society, he has received Gold Stars for academic excellence every semester. He plans to attend medical school after taking a year to travel and conduct research.