- 24 - 

 GROUND WATER QUALITY 



Saskatchewan 



Ground water sampling continued in 1988 at the locations specified in 

 the Technical Monitoring Schedule. 



Water Quality in the Tills 



The overall quality of ground water from the tills is expressed in 

 Figure 11 and as plots of TDS -vs- time for each piezometer for the 

 period of record. Higher and more variable TDS concentrations are 

 associated with the tills, compared to the Empress Gravels. 



At location 2a just north of the polishing pond, piezometer C712B 

 shows an increase in boron concentration from less than 1 mg/L in 

 July, 1987 to 6.93 in November, 1988. TDS in piezometer C712B has 

 shown considerable variation since monitoring began in 1980. 



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

 north end of the polishing pond, 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 and C719. The much higher sulphate concentrations 

 in C719 compared to C718 may be due to the presence of gypsum, 

 distributed unevenly throughout the till. 



At location 8a, west of cell No. 1 of the ash lagoon, piezometers 

 C726A, C726B, C726C, and C726D display no consistent changes in water 

 quality since 1987. 



