Publication Date

8-2024

Advisor(s) - Committee Chair

Jason Polk, Chris Groves, Pat Kambesis, Getahun Agga

Degree Program

Department of Earth, Environmental, and Atmospheric Sciences

Degree Type

Master of Science

Abstract

Karst areas in general face severe groundwater contamination problems that can degrade their water quality. In comparison to other landscapes, groundwater within karst regions is more susceptible to contamination. The situation gets worse when agriculture is practiced in these karst regions, because the nutrients and bacteria like nitrates and E. coli (Escherichia coli) are released into the groundwater systems which contaminate the water quality of those karst groundwater systems. This research aims to study the impacts of these contaminants, specifically nitrates and E. coli., by identifying the contaminant transport mechanisms and source tracking of these contaminants in the groundwater under agricultural land use, to provide reliable and robust data that can help the policymakers to make decisions that are environmentally conscious.

The study was conducted at two sites, Crumps Cave and the Church Karst Window situated in south-central Kentucky. Grab samples of water were collected from both sites. During storm events, higher-resolution samples were collected to capture the contamination that occurs during rainfall. Basic geochemistry like pH, turbidity, dissolved oxygen, conductivity, and temperature were recorded using the YSI ProDSS probe. The collection specifically for nitrate was done using the new EXO probes. The water samples were analyzed at the HydroAnalytical lab in Bowling Green, Kentucky. E. coli was measured using the IDEXX method. The nitrates were analyzed using the method SM 4110B using an ion chromatograph with autosampler, and Chromeleon software to interface with the chromatograph. The water samples were also sent to the USDA lab in Bowling Green, Kentucky where they partitioned the samples based on the microbial source tracking (MST) and chemical source tracking (CST) analysis. The data were analyzed statistically for the time-series occurrence of each parameter was plotted and regressed to determine relationships between each parameter. ArcGIS Pro was used to create maps that give a visual representation of the different agricultural land use areas in the karst regions, to identify possible contamination impacts.

Disciplines

Agriculture | Biology | Environmental Sciences | Life Sciences | Physical Sciences and Mathematics

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