ANTHROPOGENIC INFLUENCE ON SURFACE WATER CHEMISTRY IN THE BIG SANDY AND LICKING RIVER WATERSHED, KENTUCKY

This research investigates the profound implications of human activities on surface water chemistry, particularly within the Big Sandy and Licking River Watershed in Kentucky, covering approximately 8000 square miles. The complex interplay of hydrological, landscape, and anthropogenic factors poses a challenge when unraveling the sources and consequences of organic and inorganic contaminants on a watershed scale. The study relies on data collected over 50 years from diverse sources such as the EPA, USGS, and KGS. The primary contributors to streamflow, including rain, groundwater, and snowmelt, exhibit significant annual variations. The research categorizes the comprehensive dataset into major elements, trace elements, bulk organics, organic wastewater contaminants (OWCs), and pesticides. Throughout the watershed, major and trace element concentrations start at low levels in the headwaters, intensifying as they traverse the urban corridor, with a noticeable surge downstream from the initial major wastewater treatment plant (WWTP). Inorganic tracers like boron, gadolinium, and lithium prove invaluable in pinpointing anthropogenic inputs. Regardless of hydrological conditions, the study identifies the presence of OWCs and pesticides downstream from the WWTP outfall and in the headwater region. An increase in anthropogenic-derived contaminants especially correlates with higher basin population density. Biogeochemical fingerprints align with previous findings, highlighting the impact of land use on nutrient behavior and trace elements. Urban land uses display stronger correlations with nutrients, especially phosphorus, than agricultural land uses, suggesting potential influences from fertilization, wastewater, or seasonal variations during sample collection. This research emphasizes the complex task of identifying sources and impacts of contaminants at the watershed scale due to the multitude of processes occurring over time and space. By leveraging diverse datasets and innovative analytical approaches, the study contributes essential insights into the complex dynamics of surface water chemistry in the studied watershed.