Atrazine soil interactions

In addition to SOM, clay minerals are another important component that may influence contaminant-soil interactions. Expandable 2 1 type clays are usually more reactive than other clay minerals. Park et al. (2003) used a K-saturated montmorillonite as a sorbent to evaluate the availability of sorbed atrazine to three atrazine-degrading bacteria. K-saturated montmorillonite has a high atrazine sorption capacity with a Freundlich sorption... 

Dunigan, E.P. and T.H. McIntosh (1971). Atrazine-soil organic matter interactions. Weed Sci., 19 279-282. 

Carrizosa MJ, Hermosin MC, Koskinen WC, Cornejo J (2004) Interactions of two sulfonylurea herbicides with organoclays. Clays Clay Miner 52 643-649 Celis R, Hermosin MC, Cornejo J (2000) Heavy metal adsorption by functionalized clays. Environ Sci Technol 34 4593-4599 Chappell MA, Laird DA, Thompson ML, Li H, Teppen BJ, Johnston CT, Boyd SA (2005) Influence of smectite hydration and swelling on atrazine sorption behavior. Environ. Sci Technol 39 3150-3156 Chiou CT (1989) Theoretical considerations of the partition uptake of nonionic organic compounds by soil organic matter. In Sawhney BL, Brown K (eds) Reactions and movement of organic chemicals in soils. Soil Science Society of America, Madison, WI, pp 1-29... 

A variety of studies have shown that as temperature increases, sorption may increase, decrease, or remain the same, with isosteric heats of sorption being very low (Table 21.7). These studies have used the batch slurry technique, so the impact of temperature on water-triazine interactions may mask surface-triazine interactions. In contrast, at 10% soil moisture isosteric heats of atrazine sorption ranged from -10 to -12kcal/mol determined with the SF technique (Koskinen and Rochette, 1996). Sorption coefficients in field-moist soils were much greater than are typically obtained with the batch slurry system, while heats of sorption were much more negative, indicating greater sorption at low moisture contents. 

Wang, Z., D.S. Gamble, and C.H. Langford (1992). Interaction of atrazine with Laurentian soil. Environ. Sci. Technol., 26 560-565. 

Masaphy and Mandelbaum (1997) indicated that long-term irrigation with treated wastewater increased organic matter in soil but decreased the overall mineralization rate of atrazine. The authors indicated that initial atrazine mineralization was greater in soils irrigated with treated wastewater, but after a few days of interaction between the soil and the applied herbicide, mineralization rates decreased as a result of decrease in bioavailability. 

The interactions between y-triazines and microorganisms have been studied over nearly 50 years and new research has led to important discoveries. The isolation of pure cultures that are able to modify or completely mineralize y-triazines has led to the discovery of new genes and enzymes that are involved in the degradation and mineralization of y-triazines by soil bacteria. Studies carried out in soils with a history of repeated y-triazine applications indicate that rapid degradation and mineralization of atrazine developed in various soils (Barriuso and Houot, 1996 Bradley et al, 1997 Pussemier et al, 1997). 

It appears that pesticides with solubiHties greater than 10 mg/L are mainly transported in the aqueous phase (48) as a result of the interaction of solution/sediment ratio in the mnoff and the pesticide sorption coefficient. For instance, on a silt loam soil with a steep slope (>12%), >80% of atrazine transport occurs in the aqueous phase (49). In contrast, it has been found that total metolachlor losses in runoff from plots with medium ground slopes (2—9%) were < 1% of appHed chemical (50). Of the metolachlor in the runoff, sediment carried 20 to 46% of the total transported pesticide over the monitoring period. 

The interaction of soil carbohydrate with atrazine is only weak, whereas... 

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