National Toxic Substances Study:
Pharmaceuticals, Hormones, and Other Organic Wastewater Contaminants in
U.S. Streams, 1999-2000: A National Reconnaissance
Dana Kolpin, Edward Furlong, Michael Meyer,
Michael Thurman, Steven Zaugg, Larry Barber and Herbert Buxton, USGS
of this investigation is to develop information and tools on emerging
water-quality issues that will be used to design and improve water-quality
monitoring and assessment programs of the USGS and others, and for proactive
decision-making by industry, regulators, the research community, and the
There are two components of the activities conducted under this investigation:
• Methods Development, and
• Field Studies.
Development: Laboratory analytical methods are continually being
developed that enable the analysis of new compounds in environmental samples
at the low concentrations necessary to understand factors that effect
contaminant occurrence, transport and fate. Initial focus has been measuring
95 unique chemicals in water. Methods development activities are planned
for various environmental media (water, sediment, tissue, and air), as
dictated by the potential occurrence and cycling of contaminants. These
methods are being developed in mulitiple USGS research laboratories with
high concern for the ability to produce reliable data. This web page will
be updated as new methods are developed and published.
Studies: Field studies are designed to provide basic scientific
information related to the occurrence and potential transport of contaminants
in the environment. These studies will: provide increased understanding
of various contamination sources (spills, leaks, wastewaters, waste-disposal
facilities, and intended uses); identify what contaminants enter the environment,
at what concentrations, and in what combinations; determine where these
contaminants are occurring in the environment (e.g. water, sediment, air,
tissue); determine spatial and temporal variations in contaminant concentrations;
and identify contaminants that can serve as indicators of waters affected
by specific types of sources.
One or more chemicals were detected in 80 percent of the
streams sampled, and 82 of the 95 chemicals were detected at least once.
Generally, these chemicals were found at very low concentrations (in most
cases, less than 1 part per billion). Mixtures of the chemicals were common;
75 percent of the streams had more than one, 50 percent had 7 or more,
and 34 percent had 10 or more.
The most frequently detected chemicals (found in
more than half of the streams) were coprostanol (fecal steroid), cholesterol
(plant and animal steroid), N-N-diethyltoluamide (insect repellent), caffeine
(stimulant), triclosan (antimicrobial disinfectant), tri (2-chloroethyl)
phosphate (fire retardant), and 4-nonylphenol (nonionic detergent metabolite).
Steroids, nonprescription drugs, and insect repellent were the chemical
groups most frequently detected. Detergent metabolites, steroids, and
plasticizers generally were measured at the highest concentrations.
This study suggests that mixtures of pharmaceuticals,
hormones, and other wastewater contaminants can occur at low concentrations
in streams that are susceptible to various wastewater sources. It provides
methodology and guidance for future monitoring and assessment of these
types of environmental contaminants, and establishes the needed foundation
for setting priorities for further study of sources, pathways and effects.
Future directions: Further analyses of these data, including
relationships to specific source types, are ongoing. The Toxic Substances
Hydrology Program is conducting research on the occurrence of organic
wastewater chemicals in susceptible wells and drinking-water sources across
the nation; assessments of antibiotics and antibiotic-resistant bacteria;
the identification of wastewater indicators; and the development of new
laboratory analytical capabilities, including sediment and fish tissue.