Date of Award

Spring 2004

Document Type



Life & Environmental Sciences

First Advisor

Sam Alvey

Second Advisor

Kyle Strode

Third Advisor

Joan Stottlemyer


Bacteria play an essential role in nutrient cycling processes essential to the survival of plant and animal life. These processes may be adversely affected by the degradation of soil quality by heavy metal pollution. Heavy metal contamination is a significant problem in southwestern Montana’s Clark Fork River Valley due to the activities of the Anaconda Copper Mining Company during the years 1884-1980. This study focused on the effects of heavy metal contamination on bacterial activities, population density, and species richness. Using dehydrogenase activity, pH, ICP-AES analysis, plate counts, and ribosomal intergenic spacer analysis (RISA), I determined the following: (i)

Availability of the heavy metals (Zn and Cu in particular) was pH-dependent; (ii) bacterial activity was pH- and metal concentration-dependent; (iii) tolerant bacterial populations were more prevalent as pH decreased and metal concentration increased; (iv) species “richness” decreased as pH decreased and concentration of metals increased; (v) RISA analysis suggested that soils contaminated with metals had lower species richness as determined by the presence of dominant bacterial communities.