3.2.5.2 Boron 



Similar to TDS, four water-quality samples were collected by the USGS for boron in 2004. The boron 

 analysis is based on the daily specific-conductance data collected by the specific-conductance monitor 

 and making use of the boron equation that was developed from water-quality samples collected from 

 1974-2002. Figure 3.8 shows that during 2004, boron concentrations in the East Poplar River at 

 International Boundary varied from 1.39 mg/L on March 15 to 2.04 mg/L on November 15. 



The 3-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 2004. 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 suggest 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 5-year moving FWC for boron displayed in Figure 3.10 remained well below the long-term 

 objective of 2.5 mg/L. 



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 December 1990 to December 2004 are 

 shown in Figures 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) - 0.04709 

 (R^ = 0.57, n = 617) 



14 



