CHE Alaska call Wednesday, February 4 th , 2015 9:00 am Alaska Time - - PowerPoint PPT Presentation

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1 CHE Alaska call Wednesday, February 4 th , 2015 9:00 am Alaska Time (10:00 am Pacific; 1:00 pm Eastern) Dr. Philippe Grandjean on Chemical Brain Drain : on Chemical Brain Drain : Only One Chance - How Contaminants in our Environment Impair

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CHE Alaska call Wednesday, February 4th, 2015

9:00 am Alaska Time (10:00 am Pacific; 1:00 pm Eastern)

Dr. Philippe Grandjean
n Chemical Brain Drain:

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n Chemical Brain Drain:

Only One Chance - How Contaminants in our Environment Impair Brain Development

www.chemicalbraindrain.info

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Erroneous and dangerous assumptions:

The placenta protects the fetus
Children are just little adults

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Children are just little adults
Poisonings are reversible
Proof is needed for regulation
Testing is too expensive

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Sensitive brain development

Cell division

In third trimester about 12,000 nerve cells are formed every minute

Differentiation

Different types of neurons and glia cells

Migration

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Migration

Distances up to 1,000 times the size of the cell

Axon formation

Total length by age 20 years: 176,000 / 149,000 km (m/f)

Generation of synapses

Up to 1,000 new synapses per second early postnatally

Weeding of synapses

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Brain development gone astray

…in every case the mother was healthy, and it was not until more than three months after birth that the symptoms were recognized

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were recognized

Shoji Kitamura (1959)

Photo: W. Eugene Smith

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Focal Widespread

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Diffuse

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90 70 50 Percent correct responses on MCAS math test in 4th grade Averages for 351 Massachusetts municipalities: Children born in 1992 and 1999

Exposure limit (CDC) 7

10 30 50 70 50 30

Average blood-lead (µg/L) at preschool age

and 1999

(Jessica W. Reyes, 2012)

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Chemical group Known in 2006 Newly identified Metals/inorganic compounds Arsenic* Lead* Methylmercury* Fluoride* Manganese* Organic solvents (Ethanol) Tetrachloroethylene*

Chemical brain drainers

8 Organic solvents (Ethanol) Toluene* Tetrachloroethylene* Pesticides Chlorpyrifos* DDT/DDE* Other organic compounds Polychlorinated biphenyls (PCBs)* Brominated diphenyl ethers* Total 6 6

(Grandjean & Landrigan, Lancet Neurology, 2014) *Endocrine disruptor, according to TEDX

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Neurotoxicant dose (

subjects affected

Silent pandemic

Subclinical effects in child populations 9 Time of recognition

e (inverted scale)

Number of s Neurotoxicity In adults Poisoning incidents

(Grandjean and Landrigan, The Lancet, 2006)

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Neurotoxic Neurotoxic to humans N > 200 Known neurotoxic to humans during development, N > 10 10 Chemical universe N ~ 100,000 Neurotoxic in lab tests N > 1,000

(Updated from Grandjean and Landrigan, The Lancet, 2006)

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(James J Heckman, 2008)

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The goal: Full integrity of the brain to allow optimal brain functions We need it: The brain

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The brain determines behavior, IQ, endocrine functions... and who we are

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What can be done?

Mothers, consumers can make choices to

decrease exposures

An OECD test protocol is available to test

for developmental neurotoxicity in rodents

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New cell-based tests are faster, cheaper
Updated regulation of toxic substances
Chemicals control needs to include focus
n brain development
International clearinghouse

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