equilibrates with surface C02 pressures. This process would allow 

 the precipitation of authigenic carbonate minerals, which is not 

 inconsistent with the relatively high concentration of calcium seen 

 in the Tooley Lake sediment sample. 



The ammonium and phosphorous (total and orthophosphate ) 

 concentrations reported were high in comparison to the Rocky 

 Mountains sample sites, while the total organic carbon 

 concentration ranked mid-range against the class including WET68. 

 Trace element concentrations were also uniformly low; copper and 

 iron concentrations ranked mid-range or lower, while other trace 

 elements were below reporting limits. 



Chemical history. Three previous measurements of specific 

 conductance at uncertain points in Tooley Lake are known, all 

 higher than the 435 microsiemens/cm recorded in August 1994. June 

 and October, 1968 measurements were 670 and 800 microsiemens/cm, 

 respectively; in July, 1988 a measurement of 550 microsiemens/cm 

 was recorded. The pH measurement of 9.3 accompanying the 1988 

 specific conductance measurement is the only other known chemical 

 measurement from Tooley Lake. 



Substantial gradients in pH and in cation distribution probably 

 exist within Tooley Lake, as apparent ground-water inflow 

 circulates through the lake basin and equilibrates with atmospheric 

 conditions. 



Sediments. The relatively high extractable calcium concentration 

 is consistent with some level of authigenic carbonate precipitation 

 from influent ground water. Extractable arsenic and copper 

 concentrations rank toward the lower end of the range shown by 

 Rocky Mountain sites, while boron, selenium and zinc concentrations 

 rank mid-range within the site class. Most other extractable trace 

 element concentrations were below reporting limits. None exceeded 

 the mean concentrations for soils and other surficial materials of 

 the western United States. 



