1. Why the Whole world should be vitally intersted in Arsenic An exmple of a problem we missed till it was serious National Health Research Insititute Richard Wilson Mallinckrodt Research Professor of Physics, emeritus Harvard University May 20th 2010

2. Epidemiology is a blunt instrument We need an increase of ~10% before we believe it We depend on large(unwanted) historical exposures from mistakes of mankind. Can we do better?

3. 1900: mankind asked rats and mice. If a substance was toxic to a rat, then assumed to be tocic to a man AT A COMPARABLE DOSE 1960: extemded to carcinogenic potency lifetime total exposure and lifetime incidence. Rats and Mice agreed to within a factor of 10 although dioxin/saccharin is 100,000

4. 20 human examples for carcinogenic potency but most seemed to agree: Rats and mice did not get cancer. Why should people? We ignored warnings from 1886 on Hutchinson) CJ Chen shocked us The magnitude of the world disaster in enormous 50 times worse than Chernobyl Only recently has Jack Ng in Brisbane persuaded mice to get cancer We want to understand this before we have anoither big disaster.

5. The next problem: Physical shape and size: Surface chemistry ASBESTOS Animals tell us little. Serpentine asbestos and amphiboles are VERY different under an electron microscope Yet the EPA treats them the same

6. Even worse! The world is developing NANOTECHNOLOGY VERY different surface properies Toxicology of the bulk material tells us little carbon naotubes can be made to look like asbestos fobers for industrial purposes they can be woven they can be fire resistant BUT Are they like serpentine or like ammphibole fibers? I have not been to a conference where they even know the questions to ask.

7. We need the best fundamental scientifc thinking we can get. You helped the world by reminding us that arsenic is bad Can you go further? Please help us find and meet the next challenges!