alkalinity, and a predominantly calcium-magnesium bicarbonate type. 

 Sulphate is the second most abundant anion. 



At locations 2a (piezometer C726E), 9a (piezometer 728E), C533, C741, 

 and C742, no significant overall water quality trends are apparent. 

 During the 1984 meeting, the Bilateral Monitoring Committee recognized 

 that, due to the galvanized steel pipe used in the construction of 

 C533, iron and zinc concentrations from that piezometer have been 

 unreliable. These two parameters, therefore, have not been reported 

 in 1984. 



Due to the absence of consistent water quality trends in the Empress 

 Gravel, it appears that no significant amount of leakage from the 

 lagoons, into the gravels, has occurred. 



Montana 



Water quality sampling was conducted in September 1984. Wells 5 

 through 11 were sampled utilizing a submersible pump; wells 3 and 4 

 using a gas lift sampler; and well 2 was bailed due to the depth of 

 water. 



The ground-water chemistry appears to be stable from year to year. 

 Sulfide greater than 0.1 mg/L was detected only in samples from the 

 two Fox Hills-Hell Creek wells (4 and 11) and from one Hart Coal well 

 (2). The sulfide and sulfate values were used to calculate the 

 redox potential for these three samples. These three waters all lie 

 in the pyrite stability field. The water in well 11 is also satu- 

 rated with respect to siderite. The high iron content (0.5 mg/L) of 



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