This factsheet from the USGS gives an overview of the stream sampling being done by the USGS Toxics Hydrology Program in order to provide baseline information on the potential environmental occurrence of select "emerging contaminants" (such as human and veterinary pharmaceuticals, industrial and household wastewater products, and sex and steroidal hormones). Color maps of nationwide stream sampling sites and well sampling sites (designated as urban, agricultural, or other) are provided. A table of the target compounds is also accessible.