Human activities are reshaping water quality across every part of the hydrosphere - from headwaters to lakes, coasts, and marine environments. This session explores the transport of contaminants through interconnected waterways and the impacts to ecosystems and communities far downstream. We aim to unite scientists investigating diverse chemicals and processes across varied geographic settings by highlighting linkages between mountains, deserts, rivers, lakes, groundwater, and oceans.

Integrated science is essential for understanding how contaminants propagate through the continuum from summit to sea and guiding effective water quality management decisions in a rapidly changing world. We invite contributions that examine the movement and transformation of microplastics, black carbon, nutrients, pharmaceuticals, metals, PFAS, tire wear particles, and other emerging contaminants of concern.  We encourage talks focused on integrating techniques, such as modeling, field measurement, bench-scale investigation, advanced, AI/ML, etc., to reveal cross‑ecosystem pathways and cumulative impacts on human and ecological health.