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Banned in most parts of the world, DDT is still being produced at plants in China and India
March 17, 2009
A new study by an Arnold School scientist has an echo of Rachel Carson’s voice nearly 50 years after her pivotal book, Silent Spring, stunned the public about the risks of pesticides.
In 1964, Carlson so thoroughly documented the threat from DDT, a widely used pesticide, that eight years later the U.S. government banned it forever.
But Dr. Wilfried Karmaus of the Arnold School's Department of Epidemiology and Biostatistics has found that the ban didn't end the issue.
Wilfried Karmaus
Karmaus and a team of researchers from Michigan State University and Ohio State University have found that DDE, a contaminant or breakdown product of DDT, is still having harmful health consequences.
Their research indicates that DDE may be a contributor to obesity in the daughters of women who were exposed to the compound when they were pregnant and consumed fish contaminated with the compound.
“Our findings support the hypothesis that the fetus may be vulnerable to prenatal chemical disruption, resulting in a tendency later in life to increased body weight,” Karmaus noted in the journal Occupational and Environmental Medicine.
Karmaus said other possible endocrine effects of DDE include a “higher rate of preterm delivery, reduced growth in girls, a reduction in breastfeeding, earlier age at menarche (menstruation), higher fecundity (potential reproductive capacity), earlier age at menopause, and an elevated relative risk for diabetes.”
"Increased weight may be part of a 'DDE health syndrome,' Karmaus wrote.”In addition, it is also possible that prenatal exposure to DDE partly explains the obesity epidemic in women in different regions of the world. The effects of endocrine disruption on body weight are an important, yet poorly developed, area of obesity research."
Notwithstanding its bad reputation and persistence in the environment, DDT is still being manufactured at plants in China and India.
Karmaus’ study appears in the March 2009 online edition of the international peer review journal where it rates an “Editors choice.”
Additionally, the online report is accompanied by an editorial by Miquel Porta and Elisa Puigdomènech of Spain and Duk-Hee Lee of South Korea.
The editorial noted that the study “. . . has significant potential to advance mechanistic knowledge and public health policies.”
The study relied on data collected from a group of women residing on the west coast of Lake Michigan whose parents participated between 1973 and 1991 in the Michigan Fisheater Study which examined persistent organic pollutants (POPs) and their effect on human health.
It has been shown that anglers and fisheaters consume three times as much fish as the average American and have higher serum levels of DDE than population controls.
Lake Michigan has long been contaminated by runoff from agriculture and manufacturing. Emissions or volatilization (evaporation) of the POPs into the atmosphere also have spread them.
Scientists have found volatilization from soil and water may be repeated many times in a grasshopper-like process called “global distillation” from warm source areas to cold Polar Regions.
As a result the DDT/DDE compounds are found in the atmosphere, sediment and snow of colder climates with substantial accumulations in animals, marine mammals, and humans residing in these regions.
