12 

 3.2.5.2 Boron 



Figure 3.7 shows that during 1996, boron concentrations in the East Poplar River at the 

 International Boundary varied from 1.3 (14-February and 14-March) to 2.0 mg/L (10- June). 



The three-month boron FWC for the period of record is shown in Figure 3.8. The short term 

 objective of 3.5 mg/L has not been exceeded over the period 1975 to 1996. It can be seen that the 

 data derived from grab samples and that derived from regression with specific conductance are 

 similar, with the highs and lows in some degree of correspondence. This indicates that the 

 regression generation of boron (and TDS) values is in general terms, a valid procedure. 



The five-year boron FWC displayed in Figure 3.9 remained well below the long-term objective 

 of 2.5 mg/L. From mid- 1993 to the end of the data period there is a distinct drop in the computed 

 values. The reason for this drop is not known at this time. 



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

 location during the period 1975 to 1996 is described by the equation: 



boron = (0.0013 x specific conductance) - 0.092 

 (R^ = 0.61, n = 517) 



