Spatiotemporal distribution of the anti-diabetic drug, metformin, in the Lower Columbia River and its effect on phytoplankton growth

Water quality impacts both human and ecosystem health. Many pharmaceuticals and personal care products are considered contaminants of emerging concern (CEC) due to their bioactive properties. Among these, metformin—the most commonly prescribed drug for treatment of type 2 diabetes—has been reported at high concentrations (μg L-1) in stream, lake, and estuary surface waters in the United States. However, a propensity for broad-scale CEC surveys has prevented seasonal and spatial monitoring of metformin in river systems. Moreover, the effect of metformin in river food webs remains poorly explored, despite its known action on conserved eukaryotic enzymes (AMPK/SnRK1/SNF1). This project comprised the first spatiotemporal characterization of metformin in a high-discharge river system and examined the effects of metformin on aquatic primary producers.