LAND USE IMPACTS THE DISTRIBUTION OF ORGANIC CONTAMINANTS IN THE OCONEE RIVER WATERSHED IN GEORGIA

The ecological decline of freshwater ecosystems is significantly driven by land use and economic activities, which result in habitat degradation, the spread of invasive species, and chemical pollution. This study undertakes a comprehensive quantitative analysis of emerging organic contaminants in Georgia's river systems, focusing on their levels and distribution. We conducted a broad-spectrum assessment at five strategically selected sampling sites across the North Oconee River and Oconee River watershed, chosen due to their diverse land use patterns—including urban, recreational, and forest areas—making them susceptible to stormwater runoff. Over eight sampling events from August 2023 to April 2024, we detected approximately 15 organic contaminants, including various pesticides and polycyclic aromatic hydrocarbons (PAHs). Notably, organophosphates such as malathion and organochlorines such as atrazine were consistently found at all locations. Additionally, in elevated concentrations, PAHs like acenaphthene, phenanthrene, naphthalene, and fluoranthene were present. The concentration of these contaminants varied distinctly with land use, with recreational areas showing lower pesticide levels compared to forest and urban sites, although some PAHs were higher in recreational and urban areas. Our findings indicate that different land use activities influence contaminant concentrations across different locations and seasons, supported by statistical analyses. This study underscores the need for targeted management strategies to mitigate the impact of land use on freshwater quality.