Real Science for Real People

Are We Medicating the River?


By Beth Ravit


Most people are aware that excessive use of antibiotics has resulted in the health-threatening situation of antibiotic-resistant strains of microorganisms. Within the last 5 years, scientists have also found that antibiotics and other pharmaceuticals are now contaminating our rivers, groundwater and soils (Nature, July 2003). The initial studies researching this problem have mainly been conducted in Europe, and few people outside the scientific research community realize the potential scope of this problem. The one agency within the U.S. government that has taken a leadership role in addressing the problem is the U.S. Geological Survey (USGS) through its Toxic Substances Hydrology Program.

USGS has provided the first nationwide survey of pharmaceuticals, hormones and organic contaminants in our waterways. Pharmaceutical contamination is generated by multiple sources that include residential, industrial and agricultural facilities. During 1999-2000, USGS collected and analyzed water samples at 139 streams in 30 states that were downstream of heavily urbanized or agricultural areas. The survey found human and veterinary drugs (including antibiotics), natural and synthetic hormones, detergent metabolites, plasticizers, insecticides or flame retardants in 80% of the streams sampled. Survey sites in New Jersey include the Whippany River near Pine Brook and the Hohokus Brook in Hohokus.

Courtesy USGS.
Locations of sampling sites, including several in New Jersey --
most of which are contaminated with pharmaceuticals, hormones
and other organic contaminants.

Although 95 of the chemicals sampled are used extensively, there is little information available about the extent of the occurrence of these compounds in the environment, and USGS had to develop new laboratory methods to measure concentrations of these substances. Mixtures of the chemicals were common; 75% of the streams sampled had more than one chemical and 34% had 10 or more. The chemical groups most frequently detected included steroids, nonprescription drugs, and insect repellents. The highest chemical concentrations were found in detergent metabolites, steroids and plasticizers. Compounds found include coprostanol (steroid), cholesterol, caffeine, triclosan (disinfectant) and di-ethyltoluamide (insect repellent).

Knowledge of potential human and environmental health effects of these compounds (or mixtures of these compounds) is not well known. Drinking-water standards or other health criteria have been established for only 14 of the compounds. One-third of the compounds are believed to be hormonally active and half are pharmaceutically active. According to USGS, little is known about the potential health impact to humans or aquatic ecosystems exposed to levels of most of the chemicals or mixtures found.

The USGS emphasizes that this study is only a starting point that establishes the need for prioritizing sources, pathways, and effects of the pharmaceuticals, hormones and organic contaminants that are entering our surface waters. We hope that EPA, FDA, and other agencies charged with protecting human health will follow the lead of USGS on this important issue.


This study can be found at: I would very much like to hear your comments, concerns and questions about Real Science for Real People. You can contact me via email at: I look forward to hearing from our readers.

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