In recent
years, the prevalence of developmental disorders such as autism,
attention-deficit/hyperactivity
disorder (ADHD) and dyslexia
have soared. While greater awareness and more sophisticated diagnoses are
partly responsible for the rise, researchers say the changing environment in
which youngsters grow up may also be playing a role
In 2006, scientists from the Harvard
School of Public Health and the Icahn School of Medicine at Mount Sinai
identified five industrial chemicals responsible for causing harm to the brain — lead, methylmercury,
polychlorinated biphenyls (found in electric transformers, motors and
capacitors), arsenic (found in soil and water as well as in wood preservatives
and pesticides) and toluene (used in processing gasoline as well as in paint
thinner, fingernail polish and leather tanning). Exposure to these neurotoxins
was associated with changes in neuron development in the fetus as well as among
infants, and with lower school performance, delinquent behavior, neurological
abnormalities and reduced
IQ in school-age children.
Now the same researchers have reviewed
the literature and found six additional industrial chemicals that can hamper
normal brain development. These are manganese, fluoride, chlorpyrifos,
dichlorodiphenyltrichloroethane, tetrachloroethylene and polybrominated
diphenyl ethers. Manganese, they say, is found in drinking water and can
contribute to lower math scores and heightened hyperactivity, while exposure to
high levels of fluoride from drinking water can contribute to a seven-point
drop in IQ on average. The remaining chemicals, which are found in solvents and
pesticides, have been linked to deficits in social development and increased
aggressive behavio
The research team acknowledges that
there isn’t a causal connection between exposure to any single chemical and
behavioral or neurological problems — it’s too challenging to isolate the
effects of each chemical to come to such conclusions. But they say the growing
body of research that is finding links between higher levels of these chemicals
in expectant mothers’ blood and urine and brain disorders in their children
should raise alarms about how damaging these chemicals can be. The developing
brain in particular, they say, is vulnerable to the effects of these chemicals,
and in many cases, the changes they trigger are permanent.
“The consequence of such brain damage
is impaired [central nervous system] function that lasts a lifetime and might
result in reduced intelligence, as expressed in terms of lost IQ points, or
disruption in behavior,” they write in their report, which was published in the
journal Lancet Neurology.
They point to two barriers to
protecting children from such exposures — not enough testing of industrial
chemicals and their potential effect on brain development before they are put
into widespread use, and the enormous amount of proof that regulatory agencies
require in order to put restrictions or limitations on chemicals. Most control
of such substances, they note, occurs after negative effects are found among
adults; in children, the damage may be more subtle, in the form of lower IQ
scores or hyperactivity, that might not be considered pathological or
dangerous. “Our very great concern is that children worldwide are being exposed
to unrecognized toxic chemicals that are silently eroding intelligence,
disrupting behaviors, truncating future achievements and damaging societies,
perhaps most seriously in developing countries,” they write. “A new framework
of action is needed.”
Read more: Children Exposed to More Brain-Harming Chemicals Than Ever Before | TIME.com http://healthland.time.com/2014/02/14/children-exposed-to-more-brain-harming-chemicals-than-ever-before/#ixzz2u3OqBYBH
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