Title  : Inorganic Tracer Use - Lake Fryxell
Type   : Antarctic EAM
NSF Org: OD / OPP
Date   : June 27, 1991
File   : opp93031



                                       DIVISION OF POLAR PROGRAMS
                         OFFICE OF SAFETY, ENVIRONMENT AND HEALTH
                                                     202/357-7766
MEMORANDUM

   Date:  June 27, 1991

   From:  Environmental Officer, DPP

Subject:  Environmental Action Memorandum (Inorganic Tracer Use
            at Lake Fryxell)

     To:  Files (S.7 - Environment)
          Manager, Polar Biology and Medicine Program, DPP


I have read the draft proposal submitted to the Polar Biology and
Medicine Program by Dr. Diane McKnight to continue studies of the
biogeochemical cycling of the nutrient elements C, N, and S at
Lake Fryxell.  Studies in Dr. McKnight's research have revealed,
to date, that additional information about the import of
hydrologic pathways on the mixing of dissolved and particulate
matter from streams feeding the lake are needed.

Dr. McKnight's proposed use of tracers to illuminate hydrologic
pathways of these allochtonous materials follows established
experimental techniques; nonetheless, Dr. McKnight clearly
recognizes the value of Dry Valley lake ecology in proposing the
use of inorganic rather than organic tracer materials.  In
aqueous solution, the proposed inorganic tracers, LiCl and LiBr,
disassociate to ions occurring in natural waters.  In addition,
Dr. McKnight has clearly established the appropriateness and
efficiency of using these tracers in prior studies.

FINDING:  The natural presence of the constituent ions of the
inorganic tracers makes the proposed studies a more environ-
mentally-compatible approach than the alternative:  to utilize
organic dye tracers.  Introduction of the proposed inorganic
tracers is expected to have an extremely minor, transitory effect
on the ecology of glacial meltwater stream F2 (Figure 1) and of
Lake Fryxell.  The Environmental Officer approves use of LiCl and
LiBr as tracers, contingent upon their use as described in the
draft proposal.


                        Sidney Draggan