3.2.5.2 Boron 



Similar to TDS, four water-quality samples were collected by the USGS for boron in 2005. Other boron 

 data presented below were estimated using the boron equation that was developed from water-quality 

 samples collected from 1974-2003 and the daily specific conductance data collected by the specific- 

 conductance monitor. Figure 3.8 shows that during 2005, boron concentrations in the East Poplar at the 

 International Boundary varied from 1.37 mg/L on April 6 to 1.97 mg/L on August 2. 



The 3-month 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 2005. 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 for 

 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 2005 are 

 shown in Figure 3.11. 



The relationship between boron and specific conductance applied to data collected from 1974 to 2003 is 



as follows: 



Boron = (0.00129 x specific conductance) - 0.04709 



(R^ = 0.57, n = 617) 

 Note: The above equation was used to derive the missing boron water-quality sample data for 2005. 

 These derived data are used in the current annual water-quality report. 



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