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ARS Home » Southeast Area » Stoneville, Mississippi » Crop Production Systems Research » Research » Publications at this Location » Publication #216438
Title: Historical atrazine transport parameters are altered in soils exhibiting enhanced degradation

Author
item Krutz, Larry
item SHANER, DALE - 5402-10-00
item ACCINELLI, CESARE - UNIV OF BOLOGNA - ITALY
item Zablotowicz, Robert
item Henry, William

Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/2007
Publication Date: 2/5/2008
Citation: Krutz, L.J., Shaner, D.L., Accinelli, C., Zablotowicz, R.M., Henry, W.B. Historical atrazine transport parameters are altered in soils exhibiting enhanced degradation. Weed Science Society of America Meeting Abstracts. Oral Presentation at the WSSA Annual Meeting in Chicago, IL, February 5, 2008.

Interpretive Summary:

Technical Abstract: Soil bacteria have developed novel metabolic abilities resulting in enhanced atrazine degradation. Consequently, there is a need to evaluate the effects of enhanced degradation on parameters used to model atrazine fate and transport. The objectives of this study were to 1) screen Colorado (CO) and Mississippi (MS) atrazine-adapted and non-adapted soil for genes that code for enzymes able to rapidly catabolize atrazine; and 2) compare atrazine persistence, Q10, ', and metabolite profiles between adapted and non-adapted soils. The atzABC and (or) trzN genes were detected only in adapted soil. Atrazine’s average half life in adapted soil was 10-fold lower than that of the non-adapted soil and 18-fold lower than USEPA’s estimate of 3 to 4 months. Q10 was greater in adapted soil while no difference in ' was observed between soils. The accumulation and persistence of mono-N-dealkylated metabolites was lower in adapted soil; conversely, under suboptimal moisture levels in CO adapted soil, hydroxyatrazine concentrations exceeded 30% of the parent compounds initial mass. Results indicate that 1) enhanced atrazine degradation and atzABC and (or) trzN genes are likely widespread across the Western and Southern corn growing regions of the United States; 2) persistence of atrazine and its mono-N-dealkylated metabolites is significantly reduced in adapted soil; 3) hydroxyatrazine can be a major degradation product in adapted soil; and (4) fate, transport, and risk assessment models that assume historic atrazine degradation pathways and persistence estimates will likely over predict the compounds transport potential in adapted soil.