14 



-| — ' — I — ' — r 



Long— Term Objective (2.5 mg/L) 



I , I ; I . I 



J . I 



J i I 1 I . I 



1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 



Year 



Figure 3.8 Five- Year Moving, Flow-Weighted Boron Concentration for East 

 Poplar River at International Boundary. 



The relation between boron and specific conductance at East Poplar River at International Boundary 

 during the period 1975-1994 is described by the equation: 



boron = (0.00140 x specific conductance) - 0.169764 

 (R2 = 0.67, n = 493) 



3.2.5.3 Other Water-Quality Variables 



Table 3.1 lists the current multipurpose water-quality objectives for the East Poplar River at 

 International Boundary, approved by the Poplar River Bilateral Monitoring Committee. Revisions to 

 the water-quality objectives recommended by the International Poplar River Water Quality Board to 

 the IJC were made in 1992 as outlined in the 1992 annual report. Objectives for un-ionized 

 ammonia, mercury in fish tissue, and pH require further definition. No excursions occurred in 1994. 



