IATP Hog Report - Institute for Agriculture and Trade Policy

Section 3
Panhandle, where there is little rainfall and the water table is often more
than 200 feet below land surface, sheltered by layers of naturally cemented
sand and gravel, it has long been thought that it took hundreds or
thousands of years for water and waterborne contaminants to seep down to
the area's High Plains aquifer. 32 In 1999, it was learned that nitrates and
tritium have contaminated the Ogallala aquifer, the sole source of drinking
water in the Oklahoma Panhandle, and a resource that is already being
depleted by irrigation. The presence of tritium indicates that seepage is
from rainfall that fell since 1953, when atmospheric testing of hydrogen
bombs began.
In a study commissioned by the Iowa State Legislature in 1997,
investigators found that 72% of the roughly 40 earthen manure lagoons
they studied throughout Iowa are leaking faster than Iowa standards allow
and that pollution of the groundwater is "unavoidable." 33 The median
excavation depth of the lagoons was 15 feet. Thirty percent were dug more
than 20 feet into the ground. At those depths, the report stated, excavations
will intersect a continuous water-table surface, and groundwater quality
will be affected. Sixty-five percent of the site areas contained soils with
seasonally high water tables less than five feet below the ground surface.
Studies also are being and have been conducted to determine the extent of
environmental pollution by pharmaceuticals used in both animal factories
and aquaculture facilities. About half of the fifty million pounds of
antibiotics produced in the United States is for agriculture. Around eighty
percent are given for growth-promoting and prophylactic purposes as
opposed to treatment of individual animals for specific diseases. Residues
of these antibiotics may be excreted by the animals as active metabolites
or "parent substances" or else may be metabolized and excreted as inactive
components. 34,35 , 36 There is concern that this widespread use of
antibiotics may lead to contamination of ground and surface waters and
increase the potential for development of antibiotic-resistant bacteria that
could pose a risk to human health. 37 Scientists with the U.S. Geological
Survey and the U.S. EPA detected antibiotics in liquid waste from eight
hog lagoons and in well samples and surface water samples near the
lagoons. 38
In late 1998, scientists for the federal Centers for Disease Control and
Prevention studied nine Iowa hog factory sites, each with 1,000 or more
hogs. 39,40 The investigators found pathogens, including antibiotic-resistant
bacterial pathogens, metals, antibiotics commonly fed to hogs, nitrates,
and parasites (including cryptosporidium) in the manure lagoons and
surrounding wells, drainage ditches, and underground water. The
contaminants were also found in agricultural drainage wells that empty
into underground aquifers.
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