Abstract
To further understand the fate of atrazine, a herbicide of public concern in the environment, this study was undertaken to determine if atrazine degradation potential is increased in turfgrass ponds having a history of repeated exposure to agrichemicals. Two sets of mesocosms (20 L) were established: one containing sediments from a pond at the Turfgrass Research Center on the Texas A&M campus, which had repeated exposure to agrichemicals, the other containing sediments from a pond on a local horse-farm that had no contact with agrichemicals in recent years. These mesocosms were fortified with atrazine (100 [u]g L⁻¹) and incubated under aerobic and hypoxic conditions, and the concentrations of atrazine in the water and sediment were monitored. In addition, dissolved oxygen, phosphate, nitrate, and ammonium levels, and bacterial populations were monitored in the mesocosms. To determine the role of microbes in the degradation of atrazine, sterile controls were developed in a manner similar to the mesocosms. By monitoring the twelve mesocosms, it was possible to determine that the appropriate environments were maintained, and that the water chemistry was consistent with either an aerobic or hypoxic environment, as appropriate. The rates of atrazine degradation in both pond systems were very similar. Atrazine concentrations declined by about 65% in 160 days. Degradation was more rapid under aerobic conditions, but the difference was not statistically significant. Effects of prior exposure to agrichemicals on the rate of atrazine degradation were not detected. The most likely cause is that there was insufficient exposure to atrazine in the turfgrass pond to develop a population of rapid atrazine degraders.
Shourds, Shalyn Wayne (2001). Is degradation of the herbicide atrazine enhanced in turfgrass pond sediments. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -2001 -THESIS -S563.