30 



Sets of triplicate samples were split from U.S. Geological Survey sampling chums and submitted to 



tfie respective agency laboratories for analyses. Field procedures were identical to those used since 

 1986. 



Most parameters showed acceptable reproducibility within and between sets of triplicates. Only the 

 variables for which corrective action should be considered are discussed here. 



Field temperature results showed an unacceptable level of inter-agency variability with values 

 ranging from 16.5 °C to 18.0 °C. Dissoived-oxygen concentrations ranged from 10.0 to 11.2 mg/L 



Between-triplicate results were not comparable for ortho phosphorus, total ammonia, chloride, total 

 barium, total vanadium, and dissolved iron. 



For TDS, dissolved iron, dissolved boron, silica, total chromium and color, one set of results was 

 noticeably high compared to the other reported sets. Similariy one of the reported triplicate data 

 sets was low for lab pH. 



Since most of the metals were present in the samples at concentrations near or below analytical 

 detection limits, a satisfactory evaluation of data comparability for these constituents is not possible. 



