Pharmaceuticals and hormones few and at low concentrations in groundwater, USGS scientists find

Release Date:

The topic of pharmaceuticals and hormones in drinking water gets people’s attention, but if that drinking water is pumped from a well, those chemicals are less likely to be present, according to a new national study by the U.S. Geological Survey and published in the journal Environmental Science and Technology.

USGS scientists analyzed 103 pharmaceuticals and 21 hormones in samples from nearly 1,100 groundwater wells that tap drinking-water aquifers. Six percent of samples from public-supply wells and 11 percent of samples from wells used for domestic supply or other uses contained one or more pharmaceuticals or hormones. When detected, the chemicals were at low concentrations and not expected to have adverse human-health effects. Just one sample contained a pharmaceutical—hydrocortisone—at a concentration that exceeded its human-health benchmark.

This is the first large-scale, systematic study of the occurrence of hormones and pharmaceuticals in groundwater used as a drinking-water supply for an estimated 80 million people across the United States. The aquifers sampled provide about 60% of the groundwater used for drinking. Samples were collected prior to the water undergoing any type of treatment. The hormones and pharmaceuticals most frequently detected were not necessarily those most heavily used, but rather those that move through groundwater easily without adhering to soil, sediment, or rock. Samples from shallow wells, particularly those drilled into fractured crystalline rocks, were more likely to contain pharmaceuticals and hormones than samples from wells in other groundwater settings. Overall, detection frequencies and concentrations for pharmaceuticals and hormones in groundwater were lower than those reported by other studies for pharmaceuticals and hormones in surface water, and similar to or lower than those for other types of organic chemicals, such as pesticides, in groundwater.


Bexfield, L.M., Toccalino, P.L., Belitz, K., Foreman, W.T., and Furlong, E.T. 2019. Hormones and pharmaceuticals in groundwater used as a source of drinking water across the United States. Environmental Science and Technology, DOI: 10.1021/acs.est.8b05592.

Related Content

Filter Total Items: 2
Date published: March 2, 2019
Status: Active

Emerging Contaminants

Emerging contaminants, or contaminants of emerging concern, can refer to many different kinds of chemicals, including medicines, personal care or household cleaning products, lawn care and agricultural products, among others. These chemicals make it into our Nation's lakes and rivers and have a detrimental affect on fish and other aquatic species. That have also been shown to...

Attribution: Water Resources
Date published: February 28, 2019
Status: Active

Groundwater Quality—Current Conditions and Changes Through Time

Is groundwater the source of your drinking water? The USGS is assessing the quality of groundwater used for public supply using newly collected data along with existing water-quality data. Learn more about this invisible, vital resource so many of us depend on.

Contacts: Bruce Lindsey
Filter Total Items: 1
Date published: January 1, 2019

Third-party performance assessment data encompassing the time period of analysis of groundwater samples collected for hormones and pharmaceuticals by the National Water-Quality Assessment Project in 2013-15

This data set includes sample information and results for third-party performance assessment samples analyzed for hormones and pharmaceuticals during the same general time period as environmental samples collected by the National Water-Quality Assessment (NAWQA) Project for a study of groundwater resources used for drinking-water supply across the United States, 2013 through 2015. Hormone a...