Re: EPA to look at how toxins affect kids

[William Prestwich <prestwic@MCMAIL.CIS.MCMASTER.CA>]

	I think it is true that the risk is higher in early development,

but it is important to put this in context. The developing fetus is being

exposed to radiation from the mother-in fact it is being bathed in it. All

tissue contains K40, quite naturally. This is nothing to do with any man

made meddling. For the average adult human, there are something like

150000 beta particles emitted every minute inside the body, with energies

ranging up to 1.3 million electron volts. In addition there is something

like 18000 gamma rays with an energy of 1.4 Million electron volts. The

cells of the fetus also contain K40 so the baby is both irradiated by the

mother and self irradiated.

	There are also lesser effects from C14 and Ra226, as well as

cosmic rays products, particularly mu mesons. So the baby's environment is

rich in a variety of ionizing radiation types-even the odd neutron. Sr90

and its daughter Y90 emit beta particles, the first with energies lower

than K40, the latter with energies somewhat higher on average. I don't

have the numbers, but I would guess any effect from Sr90 would be

negligible compared to the sea of radiation in which all living beings

develop.

Sincerely,

Bill Prestwich





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