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Geography, Geology and the Environment


Dr. Eric Peterson

Mentor Department

Geography, Geology and the Environment


Increasing sulfate (SO42-) concentrations in the water environment, corresponding with increases in urbanization and industrialization, are rising global concerns. This threatens human health and the ecosystem and geological processes, such as the weathering of carbonate rocks, which contributes to the evolution of the global carbon cycle. Identifying sources of sulfates, natural or anthropogenic, in the water environment is essential in understanding the transport and fate of sulfate. This study focuses on understanding the origin and transport of SO42- in groundwater in a saturated riparian buffer (SRB) zone adjacent to an agricultural field in McLean County. Water samples will be collected in addition to pre-existing data that spans eight years (2015- 2023) collected from thirty-seven observation wells at the study site to analyze the major contributors of SO42- at the study site and observe trends that exist between the SO42- concentrations in the water samples with seasonal changes within water types from the study site. To assess seasonal changes, seasons will be subdivided according to equinoxes and solstices, corresponding with agricultural practices: spring/planting (April - June), summer/growing (July - September), fall/harvest (October - December), and winter/fallow (January - March). The water samples will be analyzed for SO42- concentrations. Results from these analyses will be used to (1) identify the number (s) of contributory population of SO42- using cumulative probability plots calculated with SO42- concentration values and (2) assess variations in sulfate concentrations under the conditions of seasonal changes and tile conditions among the different subgroups using a two-way ANOVA test. It is expected that there will be two contributing sources of sulfate in the study area, with agriculture contributing the larger percentage. Also, sulfate concentrations are expected to be higher in the fall and winter than in the spring and summer seasons. A full understanding of sulfate dynamics in the study area would be important for future decisions on environmental management in the area.

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