STATEMENT

ROBERT M. HIRSCH

ASSOCIATE DIRECTOR FOR WATER

U.S. GEOLOGICAL SURVEY

U.S. DEPARTMENT OF THE INTERIOR

BEFORE

UNITED STATES SENATE

COMMITTEE ON ENVIRONMENT AND PUBLIC WORKS

September 6, 2007

Madam Chairman and Committee members, I appreciate the opportunity to
appear before the Committee on Environment and Public Works to testify
on the findings of U.S. Geological Survey (USGS) studies of
water-quality issues related to Concentrated Animal Feeding Operations,
commonly referred to as CAFOs.

As you may know, the mission of the USGS is to assess the quantity and
the quality of the earth's resources and to provide information to
assist resource managers and policy makers at the Federal, State, and
local levels in making sound decisions. Assessment of water-quality
conditions and research on the fate and transport of pollutants in water
are important parts of the overall USGS mission.

USGS studies over the past 10 years have shown that CAFO impacts can
include a wide variety of contaminants in many different environmental
settings. The USGS and other organizations have investigated impacts
from CAFOs that include the following: nutrients and their proximity to
receiving waters that could cause hypoxia, harmful algal blooms, or
contaminate drinking water sources; trace elements such as arsenic and
copper that can contaminate surface waters and affect fish and aquatic
plants; pathogens such as bacteria, viruses, and parasites; antibiotics
that could foster the development of antibiotic-resistant pathogens;
pesticides and hormones that can influence changes in fish reproductive
capability; and solids from feed and feathers that could limit growth of
desirable aquatic plants.

USGS research has centered on five major areas of investigation which
are designed to track contaminants from their sources, through the
environment, and to animal and human receptors: 1) analytical method
development, 2) occurrence and relative source contributions of specific
chemical and microbial contaminants and their mixtures, 3) pathways into
and through the environment, 4) source fingerprinting, and 5) ecological
effects. These areas of research are designed to provide scientific
insights into potential public and ecological health impacts as well as
provide management and policy decision makers with CAFO related
information.

*Analytical Method Development:*

The first step in assessing potential environmental contamination from
CAFOs is to anticipate and identify chemicals and microbes that are
likely to be associated with CAFO wastes and effluents. USGS scientists
continually develop new methods for identifying and quantifying
veterinary medicines, naturally occurring hormones, pathogens,
surfactants, and other compounds which are not typically monitored in
environmental settings but which are likely to be associated with a
variety of sources including, non-confined animal production, CAFOs, and
sewage treatment plants. Indeed much of our research related to CAFO
impacts on the environment thus far has focused on analytical method
development for a range of these potential contaminants in various
environmental matrices including water, sediment, and animal tissue.

*Occurrence and Relative Source Contributions:*

Because environmental contaminants have many sources, the USGS is
quantifying relative contributions and types of environmental
contaminants originating in CAFO wastes. The intent is to understand
environmental contaminants that are specific to CAFO operations.

CAFOs can be sources of nutrient introduction to the environment. Around
the Nation, the USGS finds that relative to other sources (atmospheric
sources, synthetic fertilizers, or point source nitrogen), manures were
shown to be the single largest source of nitrogen for some rivers, such
as the Susquehanna (PA), Altamaha (GA), Apalachicola (FL), White (AR),
San Joaquin (CA), and the Fox (WI). Manures are the second largest
source of nitrogen for the Potomac (VA, MD), Trinity (TX), Rio Grande
(NM), Snake (ID), Platte (NE), and Willamette (OR). In the Neuse River
Basin of North Carolina, we have found that nitrogen concentrations in
ground waters near or under areas treated with liquid swine waste tend
to be higher than areas treated with synthetic fertilizers. After 4
years of application, nitrogen concentrations from swine waste increased
by 3.5 times in shallow ground water compared to concentrations prior to
application, and median nitrate concentrations were about double from
swine spray applications compared to commercial fertilizer. In Oklahoma,
shallow monitoring wells were tested around CAFO hog operations from the
central part of the State to the northwest, and these monitoring wells
indicated considerably higher nitrate concentrations than for monitoring
wells away from CAFO installations. For 79 wells sampled in 2001, median
nitrate concentrations in wells affected by animal operations were near
30 mg/L versus about 15 mg/L for wells mostly affected by fertilizer
applications. These studies indicate a substantial influence from CAFO
operations on nitrogen concentration in the underlying aquifer, and
although the wells tested were not used for drinking water, the U.S.
Environmental Protection Agency drinking water nitrate standard of 10
mg/L was exceeded.

A study conducted in the Stillwater Basin in Ohio examined runoff from
agricultural fields for a variety of contaminants. The study showed that
veterinary antibiotics, particularly lincomycin (detected in 23 percent
of samples), were present more frequently in streams draining watersheds
with the highest animal density. Antibiotics introduced to the
environment from the many CAFO type operations are of interest because
of their potential for causing antibiotic-resistant bacteria to
proliferate. In a reconnaissance water sampling of fish hatcheries in 7
States from 2001 to 2003, the USGS found aquaculture-approved
antibiotics at low concentrations in about 15-30 percent of samples from
hatchery water.

The USGS conducted a study near a National Wildlife Refuge in Nebraska
to determine the impacts of swine operations on fecal bacteria
occurrence. For the area near hog operations in Nebraska, we found that
the CAFO was a potential source of zoonotic bacterial pathogens like
*salmonella*. Wetlands created from swine waste-water effluent had 5-50
fold greater concentrations of phosphorus, ammonia, and total nitrogen,
and 2-3 fold greater salinity compared to control sites. *Cyanobacteria*
were abundant in the created wetlands and *microcystin* toxins were also
detected in three of six wetlands sampled.

CAFO operations may also be sources of metals like copper and arsenic.
Often these metals are used as feed amendments to enhance animal growth.
Organic arsenic feed additives are used in poultry production for
increasing weight gain, improving feed efficiency and pigmentation, and
controlling bacterial and parasitic disease. The USGS has done
reconnaissance for arsenic on the Delmarva Peninsula in areas dominated
by poultry production. From our examination of storm water, soil water
and shallow ground water, it is evident that some arsenic from poultry
operations is released to the environment because concentrations in
fresh poultry litter were about 10 times the concentrations found in
soil of the area. Concentrations in most samples in the Delmarva were
generally below the drinking water standard of 10 µg/L (parts per
billion).

USGS water-quality research continues to show that contaminants in water
resources seldom occur alone and more commonly occur in mixtures with
other contaminants, including combinations of naturally occurring or
man-made inorganic, organic, or microbial contaminant groups. These
mixtures sometimes originate from similar sources but often come from
varied sources contributing contaminants to our watersheds and aquifers.

*Pathways into and through the environment:*

CAFO wastes can enter the environment directly though leaching under
lagoons, ditching, or other direct hydraulic connections or they can
enter indirectly when solid and liquid wastes are removed from CAFOs and
applied to land elsewhere as nutrient and soil amendments. Once in the
environment, various properties of chemical and microbial contaminants
as well as interactions with ambient conditions will determine their
movement and behavior. For example, some contaminants have a natural
affinity to attach to soils or organic material and therefore tend to be
sequestered close to the sources of contamination while others readily
dissolve in water and may move long distances from the introduction
location. The type of soil, amount of organic material, and indigenous
bacterial populations it contains may facilitate or retard the movement
of various contaminants.

In one study around hog operations in Iowa where tetracycline was used,
we did not find the antibiotic in the ground water or even the lagoon
berm, probably because tetracycline is known to sorb to solids and the
area soil is rich in organic matter. In contrast near a hog operation in
North Carolina where both tetracycline and sulfamethazine are used,
tetracycline was not found in monitoring wells near the lagoons, but the
sulfamethazine was found. Sulfamethazine is known to be much more mobile
in water than tetracycline.

Poultry litter is applied to croplands in the North Carolina coastal
plain as a nutrient source, as it is in many areas across the Nation,
and the application increased shallow ground-water concentrations of
nitrogen more than synthetic fertilizer applications in the vicinity.
This is an important finding because synthetic sources of nitrogen are
typically applied in readily available forms to plants as opposed to
manures, which require additional natural processing after application
and likely remain in the soils for longer periods of time. Therefore the
time between animal fertilizer application and when their nutrients
become available to plants dictates the volume needed as well as timing
of application, and understanding these factors will be crucial to
finding effective management solutions. In contrast to the North
Carolina study, however, USGS research in southwestern Missouri, where
poultry operations are also concentrated, did not find that nitrogen
concentrations increased in shallow ground water after several years of
poultry litter application was used as a soil amendment. These
differences likely represent soil and geohydrologic property differences
between the two areas studied and the time period over which the studies
were conducted. The results suggest that it is difficult to make broad
generalized statements about CAFO impacts to the environment from these
studies of limited geographic and temporal scope.

Movement of contaminants in CAFO waste also depends on farm operations
and local environmental conditions, and may reflect the hydrologic or
precipitation conditions at time of sampling. In addition, hormones and
other chemicals are excreted in a changed or transformed form after
being metabolized by animals and therefore have different toxicological,
chemical, and physiological characteristics than before they are
metabolized. Waters draining land where animals have been raised on
pasture and not subject to CAFO finishing will likely have unique
chemical signatures. These differences in water chemistries must be
understood in context with the individual species of animals raised in
CAFOs as compared with their pastured counterparts in order to
understand contaminant issues unique to CAFO management procedures. All
these factors along with the many sources of waste products from human
and animal activity contribute to wide variation in environmental
conditions at or near CAFO operations.

*Source Fingerprinting:*

In addition to development of laboratory analytical methods for specific
contaminants, the USGS is focusing on development of
"source-fingerprinting" or "source-tracking" techniques to identify
various waste, and other, sources of environmental contaminants. These
efforts include genetic as well as chemical and microbial approaches but
all share the common objective of identifying one or a few
chemicals/microbes which, when detected in environmental waters, can be
unambiguously traced back to a unique contaminant source.

As mentioned before, there are many varied sources of nitrogen to the
environment and therefore we believe it is important to determine the
different sources of nitrogen in surface and ground waters. The USGS is
developing tools to identify sources of nitrogen from CAFOs using
nitrogen isotopes and elements such as calcium, magnesium, sodium and
potassium. In test wells located in fields sprayed with swine waste,
concentrations increased after spraying by 2 to 4 times for many
elements and an isotope of nitrogen (nitrogen-15), thereby indicating
that the source of contamination was the swine waste.

Because CAFO areas can be an important source of bacteria and other
pathogens, and the antibiotics from these areas can lead to antibiotic
resistant bacteria, the USGS has been developing microbial source
tracking methods to determine pathogen contamination of environmental
waters associated with livestock sources. The approach is to distinguish
the origins of gut microbes based on source-specific characteristics
such as individual species that are host specific, like *bacteroides*
found only in humans and therefore indicative of human waste sources, or
bacteria populations resistant to antibiotics commonly used by humans
versus other animals, or looking for genetic markers that indicate
specific host-microbe interactions. While advances in these methods have
been made in recent years, microbes are most often found in complex
mixtures of waters from many waste sources originating from animals
exposed to various food and other sources of chemicals and microbes.
These, and other complexities, produce ambiguous results even within
organism specific identification procedures.

In one study on biosolids applications in agricultural fields in
Colorado, molybdenum and tungsten, and to a lesser degree antimony,
cadmium, cobalt, copper, mercury, nickel, phosphorus, and selenium, were
determined the most likely inorganic indicators of chemical migration
from biosolid applications on land to ground water or surface water.
Other approaches have included indicators that occur infrequently in
nature but are associated with specific uses and waste sources. While
these fingerprinting techniques are not yet fully developed, they will
soon be used alone or in conjunction with each other to enable the
unambiguous distinction between contaminants coming from CAFOs and the
many other potential sources of specific contaminants. This capability
will be crucial for management and policy decisions unique to CAFO
sources of environmental contamination.

*Ecological Effects:*

Because most USGS research thus far has focused on methods development
and occurrence activities we are still in the beginnings of
investigating potential ecological health effects of CAFOs. USGS
research is focused on individual as well as community-level ecological
health issues such as eutrophication/hypoxia of nearby waters, diseases
from pathogens, antibiotic resistance, and endocrine disruption.

Preliminary results have shown that fecal indicator bacteria counts in
surface waters downstream of hog operations in Nebraska have exceeded
Federal concentration standards for contact recreation, and the majority
of bacterial isolates tested were resistant to at least one antibiotic,
usually tetracycline. Initial results from the study in Nebraska near a
National Wildlife Refuge indicate that impacts to created wetlands from
nearby hog operations could pose a threat to waterfowl health due to
pathogen exposure. In Oklahoma near cattle and hog operations, the
findings were similar and although bacteria concentrations in Oklahoma
were generally lower, they have exceeded Federal standards for contact
recreation. In addition, resistance to antibiotics used in animal
agriculture was common among fecal indicator organisms found in the
Oklahoma study, especially gram positives, which includes many
well-known genera such as
[*Bacillus*](http://en.wikipedia.org/wiki/Bacillus),
[*Listeria*](http://en.wikipedia.org/wiki/Listeria),
[*Staphylococcus*](http://en.wikipedia.org/wiki/Staphylococcus),
[*Streptococcus*](http://en.wikipedia.org/wiki/Streptococcus),
[*Enterococcus*](http://en.wikipedia.org/wiki/Enterococcus), and
[*Clostridium*](http://en.wikipedia.org/wiki/Clostridium).

Information from studies in the literature and preliminary studies by
USGS have guided us to focus future CAFO research on the spread of
antibiotic resistance and the effects of hormonally active chemicals.

*Summary:*

The USGS has found CAFOs to be a source of nutrient, pharmaceutical, and
metal contaminants in nearby waters and lands receiving wastes.
Additional research is needed to determine the relative source
contributions and environmental behavior of contaminants originating
from a range of animal and land-use operations to make scientifically
credible management and policy decisions specific to CAFOs.
Identification of sources and movement of waste contaminants requires
more research on degradation and metabolic products from the many
compounds used in animal agriculture, especially pharmaceuticals in
various feed mixtures, therapies, and environmental settings. Some
potential ecological effects have been hypothesized and are currently
under investigation, including the role of CAFOs in eutrophication of
receiving waters, wildlife exposure to pathogens and endocrine
disruptors, and development of antibiotic resistance.

I appreciate the opportunity to testify on the results of USGS
assessments and research on CAFOs. I am happy to respond to any
questions from the Committee.

**References**

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