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Pollution
'damages intelligence' Saturday,
22 April 2000 The
causes are poisons such as
lead, PCBs (polychlorinated
biphenyls, synthetic compounds
used in electrical equipment),
and radiation.
A
further problem is the loss
of micronutrients like iron
and iodine through soil
erosion, impoverishing food
crops. And scientists say it
is hard to know the full
extent of the problem, because
of the difficulty of gathering
data.
The
author, Dr Chris Williams, a
social scientist at the
Institute of Education, London
University, said one problem
could compound another, with
iron deficiency in children,
for example, able to increase
their lead uptake.
"We
only have single-substance
science, which does not
account for compounding
effects. So the overall scale
of the problem is far greater
than previously
estimated."
Global
review
Dr
Williams is a fellow of the
Global Environmental Change
Programme, a £15m social
science initiative of the
Economic and Social Research
Council. He undertook a global
review of science-based
research into the impact of
environmental factors on
intelligence.
One
of his most disturbing
findings is that
epidemiologists have detected
a statistically significant
increase in the birth of
children with Down's Syndrome
which is linked to radiation
from the explosion of the
Chernobyl nuclear reactor.
The
increase was dependent on
rainfall in the period following
the explosion. Excess Down's
Syndrome births were recorded in
parts of Germany, Scandinavia
and the Lothian region of
central Scotland nine months
after the disaster.
Dr
Williams found a study by the
Russian Academy of Sciences
which said that radiation from a
uranium mine had caused mental
impairment in 95% of the
children of one town in Russia.
In
south east Asia 1.5bn people are
affected by the iron deficiency
of many Green Revolution crops,
especially maize, and even more
in the poor world are at risk
from iodine deficiency.
In
parts of the Himalayas and China
the problem is exacerbated when
deforestation allows rain to
wash the soil away, taking with
it nutrients which are essential
in the human diet.
Growing
threat to children
The
phenomenon is not new, but is
becoming worse with increased
logging and growing population
pressure.
Lead in
the environment is a threat,
with the blood-lead level of one
child in 10 in the UK high
enough for intelligence to be
affected.
In some
African cities the proportion is
nine children in ten. The
intelligence of Inuit children
in the Arctic is being damaged
by PCBs which originate in the
tropics and arrive in Canada
within a week.
Dr
Williams told BBC News Online:
"The big feeling I have
about this is in the context of
evolution.
"The
human brain is now at risk from
its own behaviour, and nothing
else in the ecosystem is harming
itself in the same way.
"Even
lemmings don't really behave
like lemmings. That's a myth.
But we are acting like lemmings.
Need
for action
"I've
seen Indian villages where the
wells have been poisoned with
fluoride, causing a loss of
intelligence. The bright people
move out, the spiral continues,
and you see what can happen to a
community.
"I'm
afraid there'll be many more
underfed, poisoned people in the
poor world unless we recognise
what is happening."
The
director of the Global
Environmental Change Programme,
Dr Frans Berkhout, said:
"This issue reveals a wider
problem that science has when
faced with complex and uncertain
environmental issues.
"Some
of the most difficult
environmental challenges are not
being adequately addressed
simply because of the
difficulties of collecting the
necessary evidence and
establishing cause and effect.
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