13 



The relation between boron and specific conductance at the East Poplar River sampling location 



during the period 1975-1992 is described by the equation: 



boron - (0.00144 x specific conductance) - 0.218 

 (r2 = 0.69, n = 449) 



The increase in boron, as was the case with TDS, can be explained by evaporative loss of water 

 brought on by the drought conditions and the use of water for cooling, both intensifying natural 

 evaporation from Cookson Reservoir 



3.2.5.3 Other Water-Quality Variables 



Table 3.1 lists the multipurpose water-quality objectives for the East Poplar River in the Intemational 

 Boundary, recommended by the Intemational Poplar River Water Quality Board to the IJC. A single 

 excursion of the multipurpose objectives occurred in 1992. On January 15th, a dissolved oxygen 

 measurement of 2.4 mg/L was below the 4.0 mg/L objective. It is believed that extensive ice cover, 

 coupled with low-flow conditions, drastically inhibited the aeration process. 



Environment Canada monitored the East Poplar River for phenoxy acid herbicides and 

 organochlorine compounds during 1992. Trace concentrations of 2,4-D (in two of five samples), 

 T^BHC (in one of five samples), a-BHC (in one of five samples) and Dicamba (in one of five samples) 

 were recorded. The presence of these compounds in prairie surface waters is well documented 

 (Integrated Environments Limited, 1991). All other organic compounds monitored were below 

 analytical detection limits. 



