3.2.5 Water Quality 



The 1981 report by the IJC to Governments recommended: 



For the March to Octot)er period, the maximum flow-weighted concentrations should 

 not exceed 3.5 milligrams per liter (mg/L) for boron and 1 500 mg/L for total dissolved 

 solids for any three consecutive months In the East Poplar River at the International 

 Boundary. For the March to October period, the long-term average of flow-weighted 

 concentrations should be 2.5 mg/L or less for boron, and 1 000 mg/L or less for total 

 dissolved solids In the East Poplar River at the International Boundary. 



The Bilateral Monitoring Committee adopted the approach that, for the purposes of comparison with 

 the proposed IJC long-term objectives, the boron and total dissolved solids (TDS) data are best 

 graphically plotted as 5-year moving flow-weighted concentrations (FWCs) which were advanced 

 one month at a time. 



Data for January, half of November, and December were unavailable for inclusion in the flow- 

 weighted concentration calculations. Samples collected in January froze and the local observer 

 discontinued collection of samples in November and December. The January grab sample for boron 

 was contaminated and unusable. No grab sample was collected in August. 



3.2.5.1 Total Dissolved Solids 



TDS data for grab samples collected by Environment Canada and the U.S. Geological Survey in 

 1994 are shown in Figure 3.3. TDS ranged from 525 mg/L (March 16) to 1 092 mg/L (September 

 20). The short-term objective for TDS is 1 500 mg/L. A time plot of the 3-month moving FWCs for 

 TDS is presented in Figure 3.4. No exceedances of the objective have been observed during any 3- 

 month period since 1 975. 



