WATER QUALITY--Method of Reporting Results of Carbon-14 Determinations 



In Reply Refer To:                           April 30, 1982
EGS-Mail Stop 412


QUALITY OF WATER BRANCH TECHNICAL MEMORANDUM NO. 82.12

Subject:  WATER QUALITY--Method of Reporting Results of 
                         Carbon-14 Determinations

Effective March 1, 1982, all results of C-14 determinations 
will be reported in terms of "percent of modern standard" 
rather than the previous units of "apparent age."  All 
calculations will be performed relative to the accepted 
contemporary standard, National Bureau of Standards oxalic 
acid.

A new laboratory code (LC 1198) has been established for 
reporting data generated on this basis.  The WATSTORE code 
that corresponds to this new lab code is 82172.  File data 
previously stored under lab code LC 0439 as "apparent age" 
will be recalculated and stored in WATSTORE in terms of 
"percent modern" at the earliest possible time; this will be 
arranged for by the Quality of Water Branch.

In order to accommodate users who wish to have "apparent 
age," based either on the 5568-year half-life or the 
5730-year half-life, a radiocarbon age conversion table is 
provided as an attachment to this memorandum.




                                 R. J. Pickering

Attachment

WRD Distribution:  A, B. S, FO, PO

Key Words:  water quality, radiochemistry, laboratories

This memorandum does not supersede any previous memorandum.