249-8 Can riverine microbial communities and physicochemical dynamics predict the fate of organic contaminants?

Session: Emerging Contaminants: Geochemical Insights and Impacts on Human and Environmental Health

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Abstract:

Organic contaminants, including pesticides and their degradation products, undergo diverse physical, chemical, and biological transformations that substantially influence their mobility, persistence, fate, and ecological impacts. A comprehensive evaluation of these intricate processes requires examining physicochemical variables such as dissolved oxygen, temperature, pH, oxidation-reduction potential, turbidity, salinity, and organic carbon content, as well as the structural and functional composition of resident microbial communities. This study integrates sediment profiling with microbial community analysis to examine these variables within a freshwater ecosystem. Water and sediment samples were systematically collected from five sites across Lake Chapman and the North Oconee River, with a focus on sediments at three designated locations. While chemical influences on contaminant behavior are extensively documented, understanding biological responses to environmental gradients is essential for gaining deeper molecular insights. To address this, microcosm experiments incorporating high-throughput 16S rRNA gene sequencing were conducted to characterize microbial diversity and dynamics. The findings revealed that microbial assemblages significantly influence the environmental fate of organic contaminants and are reciprocally affected by their presence. Additionally, the results indicated that microbial communities in sediments and river water regulate the phase distribution of organic contaminants within riverine systems. These insights highlight the critical role of microbial communities in shaping pesticide dynamics in aquatic environments and underscore the necessity for multidimensional monitoring frameworks integrating chemical, physical, and biological metrics to enhance understanding of their biogeochemical impacts.

Keywords: Riverine ecosystem, pesticides, microbial community, fate and transport

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-9260

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