My Summer Undergraduate Experience: Exploring plastic pollution and heavy metals at Roger Williams University

By Christian J. Falcon

A SIMCoast Undergraduate Experience, Summer 2026

Christian Falcon presenting his summer research at the SURF 2026 Research Symposium

My summer was spent researching plastic debris as part of Dr. Stephen O’Shea’s research group at Roger Williams University. Thousands of tons of plastic can be found on beaches and in the sediments of Rhode Island’s Narragansett Bay, motivating us to better understand the relationships between plastic pollution and heavy metal. As part of the SIMCoast Research Theme 1 effort, we collected naturally degraded plastics from the shoreline of Mt. Hope Bay and compared their physical and chemical properties to store-bought plastic samples. 

Several spectroscopy tools (FTIR, Raman, XRF, LIBS, and ICP-OES) were used for this research. These tools work by exposing a sample to energy and recording its response. Different elements (Hydrogen, Carbon, etc.) respond to energy in different ways, making it possible to identify the material that a sample is made of. These methods helped us determine the types of polymers that made up our samples and measure the how metals interacted with the surface of the plastics.

First, we matched the chemical “fingerprints” of our samples to a library of known polymer types using Fourier Transform Infrared (FTIR) and Raman spectroscopy. This allowed us to identify the types of plastic polymers in each sample.

Hand-held XRF contained by Bruker test stand

After discovering the types of plastics we were dealing with, we compared smooth plastic control samples to samples weathered using sandpaper, sediments, and ultraviolet (UV) light before and after exposing them to heavy metals. X-Ray Fluorescence (XRF) spectroscopy was then used to measure the elements present on the surface of our samples. XRF works by exposing a sample to X-rays, which cause the elements in the sample to give off unique signals. By measuring the strength of these signals, we could determine which elements were present and how much had accumulated on the plastic’s surface.

Surface depth analysis function of Keyence Digital Microscope

To look below the surface, we used Laser Induced Breakdown Spectroscopy (LIBS), a technique that uses a laser to remove small amounts of material from a sample. This allowed us to compare the chemical makeup of multiple layers of our samples at different stages of degradation and metal exposure. The laser creates a microscopic plasma on the surface of a sample, which produces unique signals for the elements present. By measuring the strength of these signals, we could determine which elements were present and how much of each element was found in a particular location within the sample.

To confirm our observations, we used Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) to measure the amount of metal bonded to a 1 cm² of each sample. ICP-OES uses a very hot plasma to break samples down into their individual elements and measures the signals produced by each element. This gave us a more precise measurement of how much metal was attached to each sample.

Our major results showed that the more degraded a plastic was, the more metal it could adsorb, or stick, to its surface. This suggests that as plastics become increasingly weathered in the marine environment, they may accumulate more metals to their surfaces. This could have environmental implications, as weathered plastics may break down into micro- and nano-plastics while also transporting heavy metals further into oceans, potentially increasing their exposure to marine life.

This project was my first experience contributing to communities through research and my first real step toward becoming a scientist. I am proud to have gained hands-on experience with different spectroscopy techniques, as well as the software and equipment used in industry. I am grateful to have had the opportunity to participate in SIMCoast’s Research Theme 1 effort!