Exploring a Potential Method to Identify and Quantify Tire Particles from Other Microplastics

Microplastics, any particle that measures in at less than five millimeters in size, are a major pollutant found in both terrestrial and aquatic environments. These highly toxic particulates have been linked to major ecological health concerns. Rubber debris commonly produced as a result of tire wear make up around one quarter of microplastics found in the ocean. However, the quantification of tire particles is difficult in a sample of river water. This is partly because of their size and because they do not fluoresce under Nile Red dye, which has been used to identify other microplastics. For this study, a tire sample was manually abraded to create similar samples of rubber microplastics. Once the tire sample was manually abraded, 152 particles were then counted and their lengths, widths, and areas were measured using light microscopy. These measurements resulted in an average length of roughly 0.75 millimeters, width of 0.67 millimeters, and area of 0.321 millimeters squared. During the abrasion experiment, particles were separated with tweezers before they were placed on the slide and observed under the microscope; therefore, it is likely that only the larger particle sizes were counted. Measurements will also be performed after a density separation is completed to quantify smaller particle sizes in the abrasion experiment. We will also experiment with a non-polar UV dye as a way to identify tire particles in a natural sample. These experiments will be used to determine whether the dye can be used to cause the rubber to fluoresce under UV, and if so, the optimal conditions for staining rubber particles and distinguishing them from other microplastics.