to reflect possible sample contamination and have been withdrawn until their 

 reliability is determined. Investigations into identifying possible sources 

 of contamination are being conducted by the United States Geological Survey. 

 Uranium data obtained by the Environment Canada show that concentrations in 

 the East Poplar River near the International Boundary are typical of background 

 concentrations found in surface waters. The concentrations are below the 

 Canadian Drinking Water Quality Guideline of 20 ug/L. 



An assessment of the metal characteristics of the river ecosystem can be 

 improved utilizing collaborative biological data. Environment Canada plans 

 on conducting studies of metals in water, sediment and biota of Cookson 

 Reservoir during 1983. It is interesting to note that during low-flow periods, 

 the East Poplar River water quality is influenced by ground-water inflow in 

 the area immediately below the reservoir. This is substantiated by the 

 higher sulphates in the East Poplar River than what was observed in the reser- 

 voir itself during these low-flow periods. A typical example is the August 

 sulphate concentrations of 292 and 108 mg/L at the International Boundary and 

 Cookson Reservoir sites, respectively. 



Cookson Reservoir 



Samples collected quarterly by Saskatchewan Environment indicate that the TDS 

 content of Cookson Reservoir discharge was predominantly less than 1,000 mg/L. 

 The boron concentrations approached 1.85 mg/L during February and were as low 

 as 0.73 mg/L during May. There was variability in chemical characteristics 

 between the upper and lower ends of the reservoir. The rather sparse data 

 set does not, however, permit an evaluation of the variations between the 

 different sampling sites on the reservoir. No unusual quality characteristics 

 have been observed. Cookson Reservoir remains a Fish-For-Fun zone, largely 

 because no information concerning mercury in fish were collected in 1982. 

 Environment Canada intends to conduct a comprehensive survey during 1983 to 

 determine the levels of mercury (and other metals) in fish, water, and sediment 

 within the reservoir ecosystem. 



16. 



