Guest guest Posted March 12, 2007 Report Share Posted March 12, 2007 > Your math is incorrect.. > And it's extreme;y hard to convert ppb to micrograms as the density of > the material is part of the equation.. Assuming that that NAS press release is self-consistent, they must be using ppb as a mass/mass ratio, as they state: " The report's findings are consistent with those of a 1999 Research Council report that found high risks of cancer at EPA's maximum allowable level for arsenic in drinking water, which at the time was 50 micrograms per liter, or parts per billion. " http://www8.nationalacademies.org/onpinews/newsitem.aspx? RecordID=10194 > but a quick and dirty calculation shows approximately: > 5 ppb = .005 mg/L ... so you're off by a decimal place. You say 5 ppb = 0.005 mg/L and I said " ten ppb is only 0.01 mg /day, by my claculation, if you drink 1L of water. " So our math agrees. 10 ppb = 10 ug/L = 0.01 mg/L. Quote Link to comment Share on other sites More sharing options...
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