Wednesday, November 15, 2006

Evaluation of the Effect of Arsenic Contamination on Selected Soil Enzyme Activities and Microbial Diversity.

Iziegbe Garuba1, Ramble Ankumah1, Abasiofiok Ibekwe2, Michelle Corley1, and Marceline Egnin1. (1) Tuskegee Univ, Dept. of Agric. and Environ. Sciences, 305 Milbank Hall, Tuskegee, AL 36088, (2) USDA-ARS, US Salinity Lab, 450 W Big Springs Road, Riverside, CA 92507

Environmental impact of different contaminants which enter the soil can alter the diversity of the soil microflora thus disrupting their ability to maintain soil quality and health. Due to the vital role played by the diverse soil microbes in soil, the measurement of the soil microbial diversity has been proposed as a key indicator of soil health. Traditional methods of evaluating microbial numbers and diversity using plate counts have been found to only account for about less than 1% of the total population and is therefore not a viable method in evaluating impact of environmental contaminants on soil quality. High arsenic levels could have a long-term toxic effect on soil microbial diversity and thus the overall soil quality. In this study we evaluated to the effects of arsenic contamination on selected soil enzyme activities and microbial diversity using Denaturing Gradient Gel Electrophoresis (DGGE). DNA was be extracted from Arsenic contaminated and non-contaminated soil samples from Florida and Arizona.  DNA was extracted and Polymerase Chain Reaction (PCR) performed using 50ng of template DNA with the primers, PRBA338f and PRUN518r, located at the V3 region of the 16s rRNA genes of bacterioplankton.  The PCR product will then be subjected DGGE. The DGGE bands were be sequenced and analyzed to determine differences in the microbial diversity in the contaminated soil and non-contaminated soil.  Our results show that arsenic contamination resulted in decrease in soil microbial population and also resulted in shifts in the microbial community as determined by DGGE.