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limited to 10 m in height without special ash stacking procedures. The 

 experimental program which was started in 1978 to determine suitable 

 types of vegetation for the exposed ash, continued in 1990. Three 

 species of grass continued to show good results. 



The water quality data continued to show slight increasing trends in 

 sodium and molybdenum; however, a leveling trend for these parameters may 

 be developing. Sulphate and fluoride concentrations have been fairly 

 erratic but appear to be developing a slight decreasing trend. Chromium 

 and strontium have both shown decreasing trends in recent years but now 

 appear to be leveling off. Vanadium has historically been quite stable 

 at fairly low levels but has decreased to below detection in 1990. 



Uranium levels have historically been quite variable but have rarely 

 exceeded detection (0.1 ng/L) in 1990. Considerably higher pH levels 

 were noted in the ponds during 1990. This was accompanied by reduced 

 boron values. Further testing in 1991 will provide more information on 

 the pH and boron values. Generally, the quality variations of the 

 filtered ash lagoon water are not unexpected in a closed system of this 

 type. Ash lagoon water quality is shown in Figure 62. 



