Date of Completion

5-31-2024

Degree Type

Honors Thesis - Campus Access

Discipline

Environmental Science (ENVS)

First Advisor

Dr. Rachel Adams

Abstract

Microplastic (MP) contamination of drinking water is a growing phenomenon and concern for public health given the potential toxicity of MPs and their chemical additives. MPs are defined as plastic particles between 1-1000 µm, or 1 µm to 1 mm, with anything smaller than 1 µm classified as a nanoplastic. MPs have been found in bottled and tap water sources, with higher concentrations in the former. Additionally, the storage time of plastic bottles and their long-term exposure to ultraviolet (UV) radiation have been documented to increase the amount of MPs in bottled water. This research investigates if short-term UV radiation exposure leads to increased shedding of MPs into bottled water. In this experiment, single-use plastic water bottles were subjected to short-term applications of UV radiation by being irradiated in direct sunlight. The bottles were then filtered and subjected to microscopic analysis. Bottles were filtered through 0.8-micron pore gold-plated membranes. For one brand of single-use polyethylene-terephthalate (PET) plastic bottles, an average MP count was quantified for a control group, a moderate UV exposure group, and an intense UV exposure group; MPs were also classified as either fragments or fibers depending on their visual appearance. After analysis, there was no statistically significant relationship between increased UV radiation exposure and increased MP detection. Bottles in the control group reported the highest average MP counts (19 fragments, 5 fibers), followed by intense UV exposure group (14.3 fragments, 3.3 fibers) and moderate UV exposure group (10.3 fragments, 0.3 fibers). However, given that UV radiation has been observed to increase MP shedding in previous research, there is reason to believe it could act as a release mechanism for smaller plastic particles, particularly nanoplastics. Although harder to detect with conventional methods, nanoplastics are a growing cause of concern and deserve attention in future plastic contamination research.

Download

Share

COinS