Dear Joshi and Tim may I ask you what this is useful for??? 1TU is defined as a ratio of tritium to hydrogen atoms of 1e-18, so by definition 1Mol of Water with 1TU contains 3e-18g of Tritium. Or in one liter with 1 TU there is 3e-18 *1000/18=1.7e-16g Tritium. If you really want to know that. But since you are talking of contaminant transport, why the hell do you want to swich units to g/l??? The Unit TU is linear to mixing of different water masses, and as far as I know the differential equations of contaminant transport, they work well with TU... So what is this good for? Use TU in your transport model! Yours Axel ***************************************** Dr. Axel Suckow Institut für Geowissenschaftliche Gemeinschaftsaufgaben (GGA); Institute for Joint Geoscientific Research (GGA); Geochronology and Isotope Hydrology (S3); Stilleweg 2; 30655 Hannover; Phone: +49 511 6432527; Fax: +49 511 6433665; e-mail: [log in to unmask] <mailto:[log in to unmask]> -----Ursprüngliche Nachricht----- Von: Joshi, Bhaskar [mailto:[log in to unmask]] Gesendet am: Mittwoch, 31. Januar 2001 18:14 An: [log in to unmask] Betreff: Re: errata Hello Tim: I shall be very grateful if you can review the following calculation for me. It is based on the input received from you 3.2 pCi/L =1 TU = 2.09E7 atoms/L (Am I right here?? How do you get the atoms/L) Now 3g Tritium = 6.023E23 atoms So 1 atom of Tritium = (3/6.023E23) g So 1TU = (2.09E7*3/6.023E23) g/L = 1.04E-16 g/L Now 1 TU = 0.118 Bq/ L (from Clark & Fritz pp. 175) so 1 TU = 1.04E-16 g/L = 0.118 Bq/L Can we then say that 1.04E-16 g of Tritium = 0.118 Bq ???? Even though Bq is a frequency unit (dps)it appears that it can be equivalenced to mass of tritium. I have to convert TU into a mass unit for a contaminant transport simulation and this is the way I found But is this valid?? I shall be very grateful for your help Regards Bhaskar Joshi : -----Original Message----- From: Timothy P. Rose [mailto:[log in to unmask]] Sent: Tuesday, January 30, 2001 10:21 AM To: [log in to unmask] Subject: [ISOGEOCHEM] errata Bhaskar, You are correct that 1 TU = 3.2 pCi/L, not the other way around. Sorry for the misinformation. I'll go a little slower before I hit the reply button next time. - Tim ***************************************************************** Timothy P. Rose Analytical and Nuclear Chemistry Division, L-231 Lawrence Livermore National Laboratory Livermore, CA 94550 Phone: 925-422-6611 Fax: 925-422-3160 email: [log in to unmask] *****************************************************************