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boron concentrations (means of 943 and 1.28 mg/L respectively) than in 

 Cookson Reservoir. 



Quality Control 



Quality control sampling was carried out at the East Poplar River at the 

 International Boundary on September 13, 1990. Participating agencies 

 included the United States Geological Survey, Environment Canada, 

 Saskatchewan Environment and Public Safety and Sask Power. 



Sets of triplicate samples were split from USGS sampling churns and 

 submitted to the respective agency laboratories for analyses. Field 

 procedures were identical to those used to 1986, 1987, 1988, and 1989. 



The results were subsequently distributed to all participants for review 

 by both field and analytical personnel. Most parameters showed good 

 reproducibility. Results for total Kjeldahl nitrogen, dissolved iron and 

 total molybdenum are not comparable. For total phosphorus, TDS and total 

 chromium, one set of results is noticeably high compared to the other 

 reported sets. Similarly, one of the reported data sets is low for 

 silica and dissolved aluminum. The results reported by one agency for 

 magnesium showed unacceptable variability. The USGS and Saskatchewan 

 Environment and Public Safety's relatively high detection limits for 

 nitrate/nitrite make it difficult to evaluate the results for these 

 parameters . 



Environment Canada will do a more detailed evaluation of all of the 

 available historical data for this comparative quality control exercise 

 and report to the Committee in early 1992. 



