Perilous
Times
Pollutants linked to a 450 percent increase in risk of birth
defects
by Staff Writers
Austin, TX (SPX) Oct 21, 2011
Pesticides and pollutants are related to an alarming 450 percent
increase in the risk of spina bifida and anencephaly in rural
China, according to scientists at The University of Texas at
Austin and Peking University.
Two of the pesticides found in high concentrations in the
placentas of affected newborns and stillborn fetuses were
endosulfan and lindane. Endosulfan is only now being phased out in
the United States for treatment of cotton, potatoes, tomatoes and
apples. Lindane was only recently banned in the United States for
treatment of barley, corn, oats, rye, sorghum and wheat seeds.
Strong associations were also found between spina bifida and
anencephaly and high concentrations of polycyclic aromatic
hydrocarbons (PAHs), which are byproducts of burning fossil fuels
such as oil and coal. Spina bifida is a defect in which the
backbone and spinal canal do not close before birth. Anencephaly
is the absence of a large part of the brain and skull.
"Our advanced industrialized societies have unleashed upon us a
lot of pollutants," says Richard Finnell, professor of nutritional
sciences and director of genomic research at the Dell Children's
Medical Center of Central Texas.
"We've suspected for a while that some of these pollutants are
related to an increase in birth defects, but we haven't always had
the evidence to show it. Here we quite clearly showed that the
concentration of compounds from pesticides and coal-burning are
much higher in the placentas of cases with neural tube defects
than in controls."
The study, which was published in August in the Proceedings of the
National Academy of Sciences, is the result of a more than
decadelong collaboration between Finnell and a team of researchers
in Shanxi, a province in northern China.
Finnell sought collaborators in China because the prevalence of
neural tube defects is much greater there than it is in the United
States. Also, because of its population policies, China is good at
tracking births.
"It's an extraordinary natural experiment," says Finnell, who was
recently recruited to the university to help anchor the Dell
Pediatric Research Institute. "It would be much harder to do this
study in the United States, where neural tube defects are more
rare. It's also an opportunity to assist the Chinese government in
their efforts to lower their birth defect rates."
Working with public health officials in four rural counties in
Shanxi, researchers collected placentas from 80 newborn or
stillborn fetuses that suffered from spina bifida or anencephaly.
Once a fetus or a newborn with such defects was identified as a
case, the placenta of a healthy newborn with no congenital
malformations born in the same hospital was selected as a control.
Finnell and his colleagues screened these placentas for the
presence of a class of substances known as persistent organic
pollutants (POPs). Common POPs include agricultural pesticides,
industrial solvents and the byproducts of burning fuels such as
oil and coal.
They found strong associations between the birth defects and high
levels of a number of compounds present in commonly used
pesticides. They also found elevated placental concentrations of
PAHs.
"This is a region where they mine and burn a lot of coal," says
Finnell. "Many people cook with coal in their homes. The air is
often black. You don't need to be a rocket scientist to say that
maybe there's something in there that isn't good for babies."
Finnell says although the environmental conditions in Shanxi are
dramatically worse than they are in most areas of the United
States, they are comparable to what the United States was like a
century ago, and the neural tube defects are not solely a Chinese
problem.
Every year approximately 3,000 pregnancies in the United States
are complicated by neural tube defects. Many other congenital
conditions, including autism, may one day prove to be related to
environmental pollutants.
"Ultimately you need enough cells to make a proper, healthy baby,"
says Finnell, "and these are the types of compounds that cause
cell death. At the most basic level, we're learning that
environmental things kill cells, and if that occurs in a critical
progenitor population at a crucial time, you're going to have
problems."