IDENTIFICATION OF MICROPLASTICS IN SEDIMENT DEPOSITS ALONG A COMMERCIALIZED AND NON-COMMERCIALIZED SEGMENT OF RACOON MOUNTAIN CAVERNS: A TALE OF TWO TOURS

Microplastics have recently been identified as a threat to freshwater and marine ecosystems. Identification and quantification, however, have proven to be a challenge in the mitigation of microplastics. Several methods have been explored to examine microplastics in sediment samples across depositional environments, and only a few studies have investigated the extent of microplastics in cave sediments and karst aquifers. Using previously described methodologies, Balestra and Bellopede (2022) developed a microplastic detection technique to identify microplastics in cave sediments. Our study expands on their technique and provides the unique opportunity to compare the quantity of microplastics in a local commercial cave and its associated wild cave. Raccoon Mountain Caverns, which is approximately 6 miles west of Chattanooga, Tennessee, has a walking tour available for tourists that includes a simple pathway that has been modified for walking. The company also provides wild cave tours that invite smaller groups to explore the non-commercialized sections of the cave. Using sediment samples collected from the commercial tour and the non-commercialized tour, microplastics were filtered and separated by density separation and dyed with a Nile Red technique. The microplastics were then identified using UV microscopy. Samples from the commercial section of the cave are compared to the non-commercial section of the cave to explore the difference between microplastic pollution in the sediments less often exposed to tourism to the sediments along the walking tour.