Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)

First Advisor

J. W. Robinson


Effect of acid rain and humic acid on aluminum toxicity. A study was carried out to find if leaf extracts could be used to counteract the effect of acid rain and aluminum in soils and lakes. Tilapia, and common shiners fish, and alligator grass plant were used to study the effects of pH and aluminum. The effect of dried leaves on the pH and the buffering capacity of deionized water and the effect of the presence of cations such as iron, calcium and magnesium on aluminum toxicity were investigated. The results of our investigation indicated a synergistic toxic effect of aluminum and acidity, with the gills' endothelia and the roots of alligator grass being the most affected by aluminum exposure at pH below 5, while the presence of leaves increased the pH of water, decreasing the toxic effect. Study revealed that the leaves that decomposed easily to form humic and fulvic acids were most effective in reducing the aluminum toxicity. Pine leaves did not mitigate the toxic effect. The presence of iron and/or phosphorus reduced the toxic effect of aluminum to fish while magnesium and/or iron reduced the toxicity of aluminum to alligator plant. A comparative study of chemical composition of old and the newly deposited plaque from heart patients. A preliminary study was initiated to compare the chemical composition of the newly deposited atherosclerotic plaque after a bypass operation and rigorous treatment, and the material that had been depositing since childhood of heart patients. The lipid composition was determined using HPLC, TLC and MS, after extraction from the plaque using 2:1 Chloroform:methanol. The metal composition was determined using ICP, after acid digestion. The results indicated a significant difference between old and new deposits in both metal concentration and the lipid composition. The number and type of lipids in the old and the new deposits from the same individual were different. Metal ratios and concentration, especially calcium, sodium and phosphorus were also different. The results indicated that a more extensive and controlled study would be useful in understanding the etiology of heart diseases.