Soil bacteria have developed novel metabolic abilities resulting in enhanced atrazine degradation. Consequently, there is a need to evaluate the eff ects of enhanced degradation on parameters used to model atrazine fate and transport. Th e objectives of this study were (i) to screen Colorado (CO) and Mississippi (MS) atrazine-adapted and non-adapted soil for genes that code for enzymes able to rapidly catabolize atrazine and (ii) to compare atrazine persistence, Q10, β, and metabolite profi les between adapted and non-adapted soils. Th e 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 the USEPA estimate of 3 to 4 mo. Q10 was greater in adapted soil. No diff erence in β was observed between soils. Th e accumulation and persistence of mono-Ndealkylated 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 (i) enhanced atrazine degradation and atzABC and/or trzN genes are likely widespread across the Western and Southern corn-growing regions of the USA; (ii) persistence of atrazine and its mono- N-dealkylated metabolites is signifi cantly reduced in adapted soil; (iii) hydroxyatrazine can be a major degradation product in adapted soil; and (iv) fate, transport, and risk assessment models that assume historic atrazine degradation pathways and persistence estimates will likely overpredict the compounds’ transport potential in adapted soil.
Krutz L.J., Shaner D.L., Accinelli C., Zablotowicz R.M., Henry W.B. (2008). Atrazine dissipation in s-triazine-adapted and non-adapted soil from Colorado and Mississippi: implications of enhanced degradation on atrazine fate and transport parameters. JOURNAL OF ENVIRONMENTAL QUALITY, 37(3), 848-857 [10.2134/jeq2007.0448].
Atrazine dissipation in s-triazine-adapted and non-adapted soil from Colorado and Mississippi: implications of enhanced degradation on atrazine fate and transport parameters
ACCINELLI, CESARE;
2008
Abstract
Soil bacteria have developed novel metabolic abilities resulting in enhanced atrazine degradation. Consequently, there is a need to evaluate the eff ects of enhanced degradation on parameters used to model atrazine fate and transport. Th e objectives of this study were (i) to screen Colorado (CO) and Mississippi (MS) atrazine-adapted and non-adapted soil for genes that code for enzymes able to rapidly catabolize atrazine and (ii) to compare atrazine persistence, Q10, β, and metabolite profi les between adapted and non-adapted soils. Th e 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 the USEPA estimate of 3 to 4 mo. Q10 was greater in adapted soil. No diff erence in β was observed between soils. Th e accumulation and persistence of mono-Ndealkylated 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 (i) enhanced atrazine degradation and atzABC and/or trzN genes are likely widespread across the Western and Southern corn-growing regions of the USA; (ii) persistence of atrazine and its mono- N-dealkylated metabolites is signifi cantly reduced in adapted soil; (iii) hydroxyatrazine can be a major degradation product in adapted soil; and (iv) fate, transport, and risk assessment models that assume historic atrazine degradation pathways and persistence estimates will likely overpredict the compounds’ transport potential in adapted soil.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.