Skip Links

USGS - science for a changing world

Scientific Investigations Report 2014–5096

Prepared in cooperation with the Minnesota Pollution Control Agency

Contaminants of Emerging Concern in Ambient Groundwater in Urbanized Areas of Minnesota, 2009–12

By Melinda L. Erickson, Susan K. Langer, Jason L. Roth, and Sharon E. Kroening

Thumbnail of and link to report PDF (1.5 MB)Abstract

A study of contaminants of emerging concern (CECs) in ambient groundwater in urbanized areas of Minnesota was completed by the U.S. Geological Survey in cooperation with the Minnesota Pollution Control Agency. For this study, water samples were collected from November 2009 through June 2012 from 118 wells located in different land-use settings. The sampled wells primarily were screened in vulnerable sand and gravel aquifers (surficial and buried glacial aquifers) or vulnerable bedrock aquifers such as the Prairie du Chien-Jordan aquifer. Sampled well depths ranged from 9 to 285 feet below land surface. Water samples were collected by Minnesota Pollution Control Agency staff. The water samples were analyzed at U.S. Geological Survey laboratories for steroidal hormones, human-use pharmaceutical compounds, human- and animal-use antibiotics, and a broad suite of organic chemicals associated with wastewater. Reported detections were censored and not counted as detections in the data analyses if the chemical was detected in a laboratory or field blank at a similar concentration.

During this study, 38 out of 127 CECs analyzed were detected among all water samples collected. Three of the detected CECs, however, were analyzed using two different analytical methods, so 35 distinct chemicals were detected. The number of detections of CECs in individual water samples ranged from 0 to 10. The three wells in proximity to landfills had the most CEC detections. One or more CECs were detected in a total of 43 samples (35 percent); no CECs were detected in 80 samples.

Of the 127 CECs included for analysis in this study, 28 have established enforceable or non-enforceable health-based water-quality standards or benchmarks. Fourteen of the 35 chemicals detected in this study have established water-quality standards, whereas 21 of the chemicals detected have no established standard or benchmark. All detections in this study were less than established health-based water-quality standards, although p-cresol was detected at a concentration nearing a health-based water quality standard. Four of the six most frequently detected chemicals—azithromycin, diphenhydramine, tributyl phosphate, and lincomycin—have no health-based water-quality standards or benchmarks.

The antibiotic sulfamethoxazole was the most frequently detected CEC, detected in a total of 14 of 123 samples (11.4 percent) by one or both analytical methods that include sulfamethoxazole as an analyte. Most (11 of 14, or 79 percent) of the detections of sulfamethoxazole were in samples from domestic wells or monitoring wells located in areas where septic systems or potentially leaking centralized sewers are prevalent. The chemical N,N-Diethyl-meta-toluamide (DEET) was detected at the highest concentration of any CEC, at 7.9 micrograms per liter. Bisphenol A was detected second most frequently of all chemicals. DEET and Bisphenol A were detected most frequently in wells in proximity to closed landfills. Samples from bedrock wells, most of which are drinking water wells that are deeper than glacial wells, had a higher percentage of wells with CEC detections compared to samples from wells completed in glacial aquifers. The higher dissolved oxygen concentrations and lower specific conductance for the bedrock wells sampled indicate shorter duration flow paths from the land surface to these wells than for wells completed in glacial aquifers.

First posted June 23, 2014

Revised September 25, 2014

For additional information, contact:
Director, Minnesota Water Science Center
U.S. Geological Survey
2280 Woodale Drive
Mounds View, Minnesota 55112

Part or all of this report is presented in Portable Document Format (PDF). For best results viewing and printing PDF documents, it is recommended that you download the documents to your computer and open them with Adobe Reader. PDF documents opened from your browser may not display or print as intended. Download the latest version of Adobe Reader, free of charge.

Suggested citation:

Erickson, M.L., Langer, S.K., Roth, J.L., and Kroening, S.E., 2014, Contaminants of emerging concern in ambient groundwater in urbanized areas of Minnesota, 2009–12 (ver. 1.2, September 2014): U.S. Geological Survey Scientific Investigations Report 2014–5096, 38 p., with appendix,

ISSN 2328-0328 (online)





Study Design


Presence of Chemicals of Emerging Concern in Ambient Groundwater


References Cited


Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: GS Pubs Web Contact
Page Last Modified: Thursday, 25-Sep-2014 13:26:34 EDT