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RE: Lab Readings in ug/L vs ppb

I don't think this is correct.  ppb is mass to mass when dealing with liquids and should be reported as ppbw (parts per billion by weight).  1 liter of sample (assume water) = 1,000 g and 1ug/1,000g = 1 ppb by weight.  If ppb were volume to volume then you would need to factor in the specific gravity of the compound of interest.  For gases however, ppb is reported as volume to volume or ppbv assuming that the ideal gas law applies.
-----Original Message-----
From: John Calcagni [mailto:John_Calcagni@p2pays.org]
Sent: Thursday, February 13, 2003 9:12 AM
To: 'Donald Sutherland'; P2Tech Listservice
Subject: RE: Lab Readings in ug/L vs ppb

One is mass to volume the other is volume to volume
1ug/liter = 1ppb is approximately accurate assuming the material has the same density as water and you are at standard conditions.
-----Original Message-----
From: Donald Sutherland [mailto:donaldsutherland-iso14000@worldnet.att.net]
Sent: Thursday, February 13, 2003 12:45 PM
To: P2Tech Listservice
Subject: Lab Readings in ug/L vs ppb

Can someone tell me how these lab testing results translate into parts per billion (ppb)?
Thanks for your help.
Donald Sutherland
Eastern Range Detected Average
 2001 ND-1.45 ug/L 0.47 ug/L
2001 ND-1.56 ug/L 0.64 ug/L
2001 ND-2.38 ug/L 0.94 ug/L

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