T178 Karst Hydrology and Hydrogeology (Posters)

Tuesday, 17 October 2023
8:00 AM - 5:30 PM
Hall B

SPATIAL VARIATIONS OF MICROPLASTIC CONTAMINANTS IN KARST SYSTEMS ACROSS KENTUCKY

Paper number: T178-3
Program: Technical Sessions
Time: 8:00 AM – 5:30 PM

Authors

Abstract

Microplastics (MPs) are emerging environmental contaminants linked to human activity which are being found in karst aquifers and caves in Kentucky and across the globe. MPs are formed due to the input and abrasion of plastic waste in the environment, frequently mobilizing in runoff and streams. Due to their size (1nm – 5mm), chemical properties, and constant generation, MPs pose numerous ecological hazards, including uptake by organisms, resistance to breakdown, and contaminant sorption. We aim to quantify MPs in karst springs and assess relationships between contamination and groundwater basin land use. Because MPs are linked to anthropogenic sources, we expect to find increased MP concentrations in karst groundwater downstream of areas with increased population density and land development.

Using the National Land Cover Dataset (2019), we classified karst groundwater basins across Kentucky into three categories which represent high, intermediate, and low levels of land development, referred to as urban, agrarian, and remote respectively. Once classified, we selected major springs from 30 of these basins to collect 2L grab samples from. Samples were vacuum-filtered using 0.45 micron filters in the lab, and examined under 45X magnification to categorize the particulate debris above 100 microns in size. Microfibers and microfragments were the predominant MPs, followed by fibers and microbeads. Our data shows that urban basins averaged the highest MP concentrations, while agrarian and remote basins both yielded similarly low concentrations. These early results suggest that land use may provide insights on where to expect contamination, particularly in urban settings. This may assist land managers develop strategies to mitigate where contaminant load is highest, leading to improved water quality in urban streams and groundwater, which would minimize downstream impacts on ecosystems and wildlife.

Geological Society of America Abstracts with Programs. Vol. 55, No. 6

doi: 10.1130/abs/2023AM-394076

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