Adding rhodamine water-tracing dye to Fourmile Creek, Iowa, during a dye-tracing test to determine the distribution and transport of emerging contaminants in streams.

Discharge from a wastewater treatment plant on Fourmile Creek, Iowa. USGS scientists have been studying the fate and transport of emerging contaminants in the Creek.

Wastewater treatment plant in the Fourmile Creek, Iowa, watershed. The discharge from plants such as this one are potential sources of emerging contaminants in streams.

A view of Fourmile Creek, Iowa, at the upper end of the reach where USGS scientists studied the fate of emerging contaminants in the stream.

USGS technician measuring the discharge of Fourmile Creek, Iowa, using standard USGS techniques during a dye-tracing test.

Collecting discharge data for Fourmile Creek, Iowa, to be used in calculating the loads of emerging contaminants in the stream.

Downloading water-quality data from a multiparameter sonde onto a field computer during an investigation of the fate of emerging contaminants in Fourmile Creek, Iowa.

The lower end of the Fourmile Creek, Iowa, study reach where USGS scientists investigated the processes that control the distribution of emerging contaminants in the stream.

A view of Boulder Creek, Colorado, at the 75th Street Bridge just downstream of where a wastewater treatment plant discharges effluent into the stream.

USGS technician measuring streamflow in Bolder Creek, Colorado, near the 75th Street Bridge site during an investigation of the fate of emerging contaminants in streams.

USGS scientists cleaning sample-processing equipment prior to taking a water sample from Bounder Creek, Colorado.

USGS scientists collecting water-quality samples for the analysis of emerging contaminants, Boulder Creek, Colorado.

Collecting a depth-integrated water sample from Boulder Creek, Colorado, using the equal-width-increment (EWI) method.