Theses and Dissertations - UTB/UTPA

Date of Award


Document Type


Degree Name

Master of Science (MS)



First Advisor

Dr. Kristine L. Lowe

Second Advisor

Dr. Michael Persans

Third Advisor

Dr. Jonathan H. Lieman


The research hypothesis was that atrazine-degrading bacteria would be detectable during the planting and rainy seasons with their populations dissipating during non-planting and dry seasons in 2010-2011. Atrazine concentration was detected in March, May, June and August for all canals with June having the highest average concentration of 0.77ppb. Gene atzA abundance was detected from June through August with July samples having the highest gene abundance of 250.6 (pg). Tolerant bacterial densities were detectable from March through June. Atrazine concentration and population abundance were not statistically different during planting and non-planting, rainy and dry seasons, although there was a trend of increased atrazine concentration, denser atrazine-tolerant bacterial populations and increased atzA abundance during rainy months. These results indicate atrazine-degrading and atrazine- tolerant bacteria are present in these canals; these organisms potentially degrade excess atrazine in the Lower Rio Grande Valley.


Copyright 2011 Ibdanelo Cortez. All Rights Reserved.

Granting Institution

University of Texas-Pan American

Included in

Biology Commons