Compounds of emerging concern in the San Antonio River Basin, Texas, 2011–12

The City of San Antonio and the surrounding municipalities in Bexar County, Texas, are among the fastest growing cities in the Nation. Increases in residential and commercial development are changing runoff patterns and likely will increase chemical loads into streams. The U.S. Geological Survey, in cooperation with the San Antonio River Authority, evaluated the concentrations and distributional patterns of selected “compounds of emerging concern” (CECs) by collecting and analyzing water-quality samples from 20 sites in the San Antonio River Basin, Tex., during 2011–12. On the basis of their chemical composition or similar uses, the CECs discussed in this fact sheet are wastewater compounds, pharmaceutical compounds (hereinafter referred to as “pharmaceuticals”), and steroidal hormone and sterol compounds (hereinafter referred to as “steroidal hormones and sterols”). Three synoptic sampling events were completed during 2011–12 to analyze for CECs in the San Antonio River Basin. Samples were analyzed for 54 wastewater compounds, 13 pharmaceuticals, 17 steroidal hormones, and 4 sterols. Overall, the concentrations of all CECs analyzed for during this study were low, generally close to or less than the laboratory reporting level.