CLUSTER ANALYSIS 

 74 vs. 79 



REVEGETATED AREA 

 74-75 21 Tubes 

 77 79 21 Tubes 



E • 74-75 (Early) 

 L- 77-79 (Late) 



L L 



3 24 1629 14 21 4 3 

 LL LL LLLE 



4 12 13 6 7 12 22 6 30 1 

 ELLLLELELE 



8 28 25 30 26 22 26 17 10 25 13 14 24 16 28 31 7 29 1031 17 21 

 ELEELEEE LLEEEEEEEEELLE 



Figure 4.— Dendrogram of soil-water samplers on the revegetated area only 1974-75 and 1977-79. 



Cophenetic correlation = 0.93. 



Revegetated 1974-75 vs. 

 Revegetated 1977-79 



The dendrogram for the revegetated area in 

 1 974-75 and 1 977-79 (fig. 4) exhibits a tendency 

 similar to that of the untreated area. That is, the 

 1974-75 samples tend to group, as do the 1977- 

 79 samples. 



We conclude that there has been some real 

 change in water quality on the revegetated area 

 over time; the concentration of copper, iron, and 

 sulfate has decreased. 



CONCLUSIONS AND 

 DISCUSSION 



On the basis of the data (table 1) and cluster 

 analysis results, we draw two conclusions regard- 



ing the influence of revegetation on water quality 

 in this acid mine waste situation: 



1. Both the revegetated and untreated areas 

 show decreasing soil-water ionic concen- 

 trations of copper, iron, and sulfate over the 

 1974-79 study. 



2. The revegetation procedures, including top- 

 soiling and liming and subsequent vegeta- 

 tive growth, have not changed the soil-water 

 ionic concentrations of copper, iron, and 

 sulfate as compared to no surface treat- 

 ment. 



Regarding the first conclusion, what is the prob- 

 able cause of the decreasing amounts of soluble 

 iron, copper, and sulfate in the soil water? There is 

 a temptation to suggest the oxidation reactions 

 are slowing down because the most reactive spoil 



7 



