IDENTIFICATION AND QUANTIFICATION OF MICROPLASTICS IN SURFICIAL SEDIMENT DEPOSITS IN COMMERCIALIZED AND NON-COMMERCIALIZED SEGMENTS OF RACCOON MOUNTAIN CAVERNS, TN

Microplastics, polymers that are typically <5mm, have been identified as a growing threat to freshwater ecosystems in recent years leading to their effects on aquatic environments to be studied. These studies have involved examining new and effective ways to identify and quantify microplastics in sediment and freshwater environments. However, microplastic contamination in karst environments is still largely underrepresented. Balestra and Bellopede (2022) highlighted the impact of microplastic pollution in cave systems that offered public tours. Cave tours are a common tourist attraction in and around Chattanooga, TN. This study explores the effects of public tours on a local cave, Raccoon Mountain Caverns, located approximately 6 miles west of Chattanooga, TN. Two types of tours are offered at Raccoon Mountain Caverns, walking tour, in which crowds walk along pre-made paths, and a wild cave tour, which involves e crawling and squeezing through the natural cave passageways. Sediment samples were collected at 6 locations in the wild cave section and 5 along the walking section of the tour. The samples were separated by particle size, and the organic matter was removed prior to microplastic extraction from the sediments using density separation and filtration was used to separate the microplastics from the sediment. Once isolated, the microplastics were stained with Nile Red dye, and then quantified using UV microscopy. Both sections from the cave were then compared to each other to determine if pollution was greater in one section than the other and possible reasons for the greater pollution. 25% of Earth’s freshwater is sourced from karst environments (Campanale et al., 2022; Balestra et al., 2023), therefore making it important to understand the correlation between exposure and microplastic accumulation and expand upon previously developed methods.