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**(Briefing Sheet prepared for a Congressional Briefing in Washington
D.C. on March 20, 2008)**

*Research by the Toxic Substances Hydrology (TOXICS) Program of the U.S.
Geological Survey since 1998 shows that chemicals used in small amounts
everyday in homes, industry, and agriculture are entering the
environment. These Emerging Contaminants (ECs) include human and
veterinary drugs, hormones, detergents, disinfectants, fire retardants,
fragrances, insecticides, and plasticizers. The pathways by which they
enter the environment include wastewater treatment plants, livestock
production and animal feedlot wastes, aquaculture, onsite septic
systems, and other industrial discharges. Information on the
contributions of different sources and the environmental circumstances
under which higher concentrations occur is being gathered. Ecological
concerns related to the uptake by aquatic and terrestrial organisms,
endocrine disruption, antibiotic resistance, and the effects of chemical
mixtures also are being investigated.*

***Visit the TOXICS Program web site:***

More information on our research is available on the Internet,
including:

-   A summary of recent accomplishments (see *Emerging Contaminant
    Headlines*) at:
    [*http://toxics.usgs.gov/regional/emc/*](http://toxics.usgs.gov/regional/emc/)

-   A complete bibliography of about 150 publications on this TOXICS
    Program research is available at:
    [*http://toxics.usgs.gov/bib/bib-Emerging.html*](http://toxics.usgs.gov/bib/bib-Emerging.html)

***Where and at what levels are ECs found?***

The USGS has been developing chemical and microbial analytical
capabilities to measure ECs at levels below a part per billion in the
environment since 1998. Currently, the TOXICS Program analyzes more than
140 ECs, including about 70 pharmaceuticals, and has collected about
2000 environmental samples across the Nation.

USGS findings show that ECs are commonly present in streams and ground
water across the U.S. at low levels (less than part per billion) and are
often found as complex mixtures. EC concentrations tend to be lower in
ground water compared to surface water (Buxton and Kolpin, 2002 and
Barnes and others, 2005).

***Where do ECs come from?***

ECs reflect a wide range of human activities, and are associated with
many different animal- and human-waste sources, such as wastewater
treatment plants, livestock production, aquaculture, onsite septic
systems in unsewered residential developments and other industrial
discharges.

A complicating aspect of many ECs is that a single source can have
multiple pathways into the environment. For example, a wastewater
treatment plant has both liquid and solid waste treatment and disposal.
Treated liquid effluent is often continually discharged from a
wastewater treatment plant to streams, with ECs in such effluent at
relatively low concentrations (parts per billion or even sub-parts per
billion) (Glassmeyer et al., 2005). In contrast, treated biosolids often
have CECs at more concentrated levels (parts per million) (Kinney et
al., 2006) and are released to the environment through periodic land
applications. These different pathways can lead to substantially
different transport and exposures.

***What affects the transport and fate of ECs in the environment?***

The presence of individual chemicals varies in streams, ground water,
and sediment because of differences in their solubility, mobility, and
persistence; the mechanisms by which they are released to the
environment; and the processes that govern the way they move and are
altered in the environment. Observations of ECs in various environmental
media (water, sediment, tissue) confirm the need to examine all
environmental compartments to fully understand potential environmental
exposure and effects. Some compounds are mobile, persistent and are
transported long distances in surface and subsurface waters, while
others tend to break down or adhere to sediment.

***What are the ecological and human health concerns?***

Ecological concerns, such as those related to the uptake of ECs by
aquatic and terrestrial organisms, endocrine (hormonal and reproductive
functions) disruption, antibiotic resistance, and other direct
ecological effects are being investigated.

Scientific evidence suggests that different ECs can have effects to
specific species (Fent et al., 2006; Oetkin et al., 2005). Veldhoen et
al. (2006) show decreased thyroid function (an example of endocrine
disruption) in frogs exposed to triclosan, a common anti-bacterial
product. Oaks et al., (2004) in a forensic-based study determined that
vultures that fed on cattle carcasses suffered renal failure from the
presence of diclofenac (an anti-inflammatory drug used in cattle in
India and Pakistan). Evidence also suggests that chemical mixtures can
act collectively to cause adverse effects, even when each component is
below their individual effect level (Brain et al., 2007; Woodling et
al., 2006).

Although ecological effects have been hypothesized, some findings have
been unanticipated, pointing to a relative lack of understanding of
potential adverse ecological effects of ECs.

Effects of ECs on human health are even less well understood. As
information on the occurrence, concentrations, and mixtures of ECs in
drinking water becomes available, toxicologists from health-related
research institutions and organizations will be better positioned to
determine potential human health effects.

***What are future research needs?***

Great strides have been made in EC research over the last decade. Many
research questions and needs remain, however. These include those
related to improved analytical capabilities for measuring chemicals,
improved techniques for assessing effects, better characterization of
environmental exposure, evaluation of the relative effectiveness of
various drinking-water and wastewater treatment technologies;
development of links between CEC occurrence with environmental exposure;
and assessments of human risk. USGS has collected data on the occurrence
of ECs at over 1500 sites across the Nation, including more than 400
streams, and 1,000 wells. These data are being used to assess our
current knowledge of the occurrence, concentrations and mixtures of ECs
in our water resources.

***Cited References***

Barnes, K.K., et al., 2005, Studies examine
contaminants---Pharmaceuticals, hormones and other organic wastewater
contaminants in ground water resources: National Driller Magazine, v.
26, no. 3, p. 38-39.

Brain, J.V., et al., 2007, Evidence of estrogenic mixture effects on the
reproductive performance of fish: Environ. Sci. Technol., v. 41, p.
337-344.

Buxton, H.T. and Kolpin, D.W., 2002, Pharmaceuticals, hormones, and
other organic wastewater contaminants in U.S. streams: U.S. Geological
Survey Fact Sheet FS-027-02, 2 p.

Fent, K., et al., 2006, Ecotoxicology of human pharmaceuticals: Aquatic
Toxicology, v. 76, p. 122-159.

Glassmeyer, S.T., et al, 2005, Transport of chemical and microbial
contaminants from known wastewater discharges: Potential for use as
indicators of human fecal contamination: Environ. Sci. Technol., v. 39,
p. 5157-5169.

Kinney, C.A., et al., 2006, Survey of organic wastewater contaminants in
biosolids destined for land application: Environ. Sci. Technol. V. 40,
p. 7207-7215.

Oaks et al., 2004, Diclofenac residues as the cause of the vulture
population decline in Pakistan: Nature, v. 427, p. 1238-1240.

Oetken, M., et al., 2005, Effects of pharmaceuticals on aquatic
invertebrates. Part I. The antiepileptic drug carbamazepine: Arch.
Environ. Contam. Toxicol. v. 49, p. 353-361.

Veldhoen, Nick, et al., 2006, The bactericidal agent triclosan modulates
thyroid hormone-associated gene expression and disrupts postembryonic
anuran development: Aquatic Toxicol. V. 80, p. 217-227.

![](media/image2.jpeg){width="3.2700787401574805in"
height="2.1244094488188976in"}Woodling, J.D., et al., 2006, Intersex and
other reproductive disruption of fish in wastewater effluent dominated
Colorado streams: Comp. Biochem. Physiol., v. 144, p. 10-15.

***Contact:***

Herb Buxton, USGS TOXICS Program

810 Bear Tavern Road

West Trenton, New Jersey 08628

Email: <hbuxton@usgs.gov>

Phone: 609-771-3944