[CPEO-MEF] Lead and risk

[CPEO Moderator <cpeo@cpeo.org>]

[POSTED BY Ted Henry (KC2TH@aol.com)]

With regard to the risks from lead, remember that lead effects have been 
found at such low concentrations that is is questionable whether there 
is even a threshold for this compound - meaning that any exposure is 
probably associated with an elevated risk of adverse effects. 

I do not believe that there is a reference dose for inhalation exposure, 
but this should not be construed as meaning this exposure pathway is 
unimportant. 

On a risk based level, note that EPA Region III RBC tables (1996) note 
that "if EPA did develop a reference dose for lead by the same methods 
used for other reference doses, we would probably find that most people 
already exceed it." 

So, we should understand that while 400 ppm is the residential soil 
number, this is not strictly driven by science. 

Ted Henry 

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