Pollution and other environmental factors may be threatening the
intelligence of millions of people around the world, according to a new
research review conducted by Chris Williams of London University.
Environmental problems that can lead to lower IQs include lead, PCBs, and
radiation. Epidemiologists have detected an increase in the number of
children born with Down's syndrome that correlates with the explosion of
the Chernobyl nuclear reactor in 1986. In Britain, one in 10 children
has high enough levels of lead in their blood to affect intelligence, and
in some African cities the ratio is nine children out of 10.
straight to the source: BBC News, Alex Kirby, 04.22.00