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GROUND WATER QUALITY 



Saskatchewan 



Ground water sampling continued in 1987 at the locations specified 

 in the Technical Monitoring Schedule. 



Water Quality in the Tills 



The quality of ground waters from the tills is expressed in 

 Figure 13 as temporal plots of total dissolved solids (TDS) for 

 each piezometer for the period of record. Higher and more variable 

 TDS concentrations are associated with the tills, compared to the 

 Empress Gravels. This is due principally to the presence of 

 soluble minerals such as gypsum and calcite in the till matrix and 

 on fracture surfaces. 



At location 2a, on the north edge of Ash Lagoon No. 2, no 

 significant trends have been observed in parameters analyzed from 

 piezometer C712B of the oxidized till. 



At locations 2b (piezometer C718) and 2c (piezometer C719) near the 

 north end of the Polishing Lagoon, there have been no consistent 

 water quality trends over the period of record. Although these two 

 sites are close together, there are large differences in the 

 quality of water from C718 (mottled till) and C719 (oxidized 

 till) . The presence of gypsum, distributed unevenly throughout the 

 till, is indicated by the much higher sulphate concentrations in 

 C719 (3 260 mg/L, July 1987) compared to C718 (198 mg/L, July 1987). 



