14 



3.2.5.2 Boron 



Boron water-quality sample data collected by Environment Canada and the USGS in 2002 at the East 

 Poplar River at International Boundary are shown in Figure 3.8. There were seven water-quality 

 samples obtained this year with boron concentrations ranging from 1.28 mg/L on May 28 to 2.06 mg/L 

 on June 13. 



The three-month moving FWC for boron for the period of record is shown in Figure 3.9. The short-term 

 objective of 3.5 mg/L has not been exceeded over the period 1975 to 2002. It can be seen that the data 

 derived from water-quality samples and that derived from regression with specific conductance are 

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

 generation of boron and TDS values is. in general terms, a valid procedure despite problems which arise 

 from attempting to generate representative concentration and flow data for an entire month, based on a 

 limited number of samples. 



The five-year moving FWC for boron displayed in Figure 3.10 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 gradual decrease in the 

 computed boron concentrations. 



Boron concentrations are not as well-correlated with specific conductance as TDS. Boron is a relatively 

 minor ion. and does not in itself contribute to a large degree to the total load of dissolved constituents in 

 the water. Accordingly, it appears likely that the standard deviation of dissolved boron (relative to the 

 long-term mean boron concentration) may be greater than that of the major cations (sodium, potassium, 

 and magnesium) and anions (sulphate, bicarbonate, and chloride) around their respective long-term 

 mean concentrations. Daily boron concentrations for the period January 1990 through December 2002 

 are shown in Figure 3.11. 



The relationship between boron and specific conductance applied to data collected from 1974 to 2002 is 

 as follows: 



boron = (0.00129 x specific conductance) - 0.0434 

 (R- = 0.58, n = 605) 



