From August 2016 to March 2017,the U.
S. Geological Survey (USGS) collected representative samples of filtered and unfiltered water and suspended sediment (including the colloidal fraction) at USGS streamgage 12113390 (Duwamish River at Golf Course, at Tukwila, and Washington) during 13 periods of differing flow conditions. Samples were analyzed by Washington-State-accredited laboratories for a large suite of compounds,including metals, dioxins/furans, and semivolatile compounds including polycyclic fragrant hydrocarbons,butyltins, the 209 polychlorinated biphenyl (PCB) congeners, or total and dissolved organic carbon. Concurrent with the chemistry sampling,water-quality field parameters were measured, and representative water samples were collected and analyzed for river suspended-sediment concentration and particle-size distribution. The results provide current data that can be used to estimate sediment and chemical loads transported by the Green River to the Lower Duwamish Waterway.
Source: usgs.gov