LUBBOCK, Texas, February
24, 2005 (ENS): In a new study of breast milk and milk
purchased in stores across the United States, scientists at Texas
Tech University found perchlorate in every sample but one. The results
suggest that the chemical may be more widespread than previously
The chemical can interfere with iodide uptake in the thyroid gland,
disrupting adult metabolism and childhood development.
Perchlorate is a waterborne contaminant left over from propellants
and rocket fuels. There are about 12,000 Department of Defense sites
in the United States that have been used for training with live
Led by Professor Purnendu Dasgupta, Ph.D. of the university's department
of chemistry and biochemistry, the researchers analyzed 47 dairy
milk samples purchased randomly from grocery stores in 11 states,
and 36 breast milk samples from women recruited at random in 18
Every sample of breast milk contained perchlorate, and only one
sample of dairy milk contained no detectable levels, researchers
The average perchlorate concentration in breast milk was 10.5 micrograms
per liter; the dairy milk average was 2.0 micrograms per liter.
No definitive national standard exists for permissible levels of
the chemical in milk, although the U.S. Environmental Protection
Agency has suggested a limit of 1.0 micrograms per liter in drinking
The researchers also found that high levels of perchlorate correlated
with low levels of iodide in breast milk, which can inhibit thyroid
function in nursing women, an essential component for proper neural
development of the fetus.
Although the data are limited, the levels of iodide in this study
are sufficiently low to be of concern, according to the researchers.
They suggest that the recommended daily intake of iodine for pregnant
and nursing women may need to be revised upwards.
In March 2003, the Texas Tech University Institute of Environmental
and Human Health received a $2 million research award from the Department
of Defense Strategic Environmental Research and Development Program
to research the effects the residues from explosives have on the
environment and how to clean up any contamination.
The program's principal investigator Ronald Kendall, Ph.D said,
"This work will be implemented to assist the Department of
Defense in developing risk assessments on explosives and breakdown
products of these compounds, and to assist in the establishment
of safe limits and in remediation," he said.
"The consequences of having explosives and their breakdown
products in the environment are not well understood," Kendall
The report was published February 22 on the website of "Environmental
Science & Technology," a peer-reviewed journal of the American
Chemical Society, the world's largest scientific society.