yeah to the industrial rich

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PUBLIC HEALTH

A Silent Pandemic: Industrial Chemicals Are Impairing The Brain

Development

Of Children Worldwide

http://www.eurekalert.org/pub_releases/2006-11/hsop-asp110306.php

Boston, MA -- Fetal and early childhood exposures to industrial

chemicals in the environment can damage the developing brain and can

lead to

neurodevelopmental disorders (NDDs)--autism, attention deficit

disorder

(ADHD), and mental retardation. Still, there has been insufficient

research

done to identify the individual chemicals that can cause injury to the

developing brains of children.

In a new review study, published online in The Lancet on

November 8,

2006, and in an upcoming print issue of The Lancet, researchers from

the

Harvard School of Public Health and the Mount Sinai School of Medicine

systematically examined publicly available data on chemical toxicity

in

order to identify the industrial chemicals that are the most likely to

damage the developing brain.

The researchers found that 202 industrial chemicals have the

capacity

to damage the human brain, and they conclude that chemical pollution

may

have harmed the brains of millions of children worldwide. The authors

conclude further that the toxic effects of industrial chemicals on

children

have generally been overlooked.

To protect children against industrial chemicals that can

injure the

developing brain, the researchers urge a precautionary approach for

chemical

testing and control. Such an approach is beginning to be applied in

the

European Union. It puts in place strong regulations, which could

later be

relaxed, if the hazard were less than anticipated, instead of current

regulations that require a high level of proof. At present in the

U.S.,

requirements for toxicity testing of chemicals are minimal.

" The human brain is a precious and vulnerable organ. And because

optimal brain function depends on the integrity of the organ, even

limited

damage may have serious consequences, " says Philippe Grandjean,

adjunct

professor at Harvard School of Public Health and the study's lead

author.

One out of every six children has a developmental disability,

usually

involving the nervous system. Treating NDDs is difficult and costly

to both

families and society. In recent decades, a gathering amount of

evidence has

linked industrial chemicals to NDDs. Lead, for example, was the first

chemical identified as having toxic effects to early brain

development,

though its neurotoxicity to adults had been known for centuries.

A developing brain is much more susceptible to the toxic

effects of

chemicals than an adult brain. During development, the brain

undergoes a

highly complex series of processes at different stages. An

interference--for

example, from toxic substances--that disrupts those processes, can

have

permanent consequences. That vulnerability lasts from fetal

development

through infancy and childhood to adolescence. Research has shown that

environmental toxicants, such as lead or mercury, at low levels of

exposure

can have subclinical effects--not clinically visible, but still

important

adverse effects, such as decreases in intelligence or changes in

behavior.

Grandjean and co-author Philip J. Landrigan, Professor at Mount

Sinai

School of Medicine, compiled a list of 202 environmental chemicals

known to

be toxic to the human brain using the Hazardous Substances Data Bank

of the

National Library of Medicine and other data sources. (The authors

note that

the list should not be regarded as comprehensive; for example, the

number of

chemicals that can cause neurotoxicity in laboratory animal tests

exceeds

1,000.) The authors then examined the published literature on the

only five

substances on the list--lead, methylmercury, arsenic, PCBs and

toluene--that

had sufficient documentation of toxicity to the developing human

brain in

order to analyze how that toxicity had been first recognized and how

it led

to control of exposure. They found a similar pattern in how the risks

of

each substance were documented: first, a recognition of adult

toxicity and

episodes of poisoning among children, followed by a growing body of

epidemiological evidence that exposure to lower levels of the

substances

caused neurobehavioral deficits in children.

" Even if substantial documentation on their toxicity is

available,

most chemicals are not regulated to protect the developing brain, "

says

Grandjean. " Only a few substances, such as lead and mercury, are

controlled

with the purpose of protecting children. The 200 other chemicals that

are

known to be toxic to the human brain are not regulated to prevent

adverse

effects on the fetus or a small child. "

Grandjean and Landrigan conclude that industrial chemicals are

responsible for what they call a silent pandemic that has caused

impaired

brain development in millions of children worldwide. It is silent

because

the subclinical effects of individual toxic chemicals are not

apparent in

available health statistics. To point out the subclinical risk to

large

populations, the authors note that virtually all children born in

industrialized countries between 1960 and 1980 were exposed to lead

from

petrol, which may have reduced IQ scores above 130 (considered

superior

intelligence) by more than half and increased the number of scores

less than

70. Today, it's estimated that the economic costs of lead poisoning

in U.S.

children are $43 billion annually; for methylmercury toxicity, $8.7

billion

each year.

" Other harmful consequences from lead exposure include shortened

attention spans, slowed motor coordination and heightened

aggressiveness,

which can lead to problems in school and diminished economic

productivity as

an adult. And the consequences of childhood neurotoxicant exposure

later in

life may include increased risk of Parkinson's disease and other

neurogenerative diseases, " says Landrigan.

The researchers believe that the total impact of the pandemic

is much

greater than currently recognized. In supplementary documentation

(see below

for a link), about half of the 202 chemicals known to be toxic to the

brain

are among the chemicals most commonly used.

Testing chemicals for toxicity is a highly efficient public

health

measure. However, less than half of the thousands of chemicals

currently

used in commerce have been tested to assess acute toxicity and,

although new

chemicals undergo more thorough testing, access to the data may be

restricted because companies fear exposing proprietary information.

Also,

current toxicity testing rarely includes neurobehavioral functions.

" The brains of our children are our most precious economic

resource,

and we haven't recognized how vulnerable they are, " says

Grandjean. " We must

make protection of the young brain a paramount goal of public health

protection. You have only one chance to develop a brain. "

To view supplementary documentation on industrial chemicals and

risks

of toxic effects on brain development, click here:

http://www.hsph.harvard.edu/neurotoxicant/appendix.doc Support for

this

research was provided by the Danish Medical Research Council, the

(U.S.)

National Institute of Environmental Health Sciences and the U.S.

Environmental Protection Agency.