Atrazine degradation products

Lerch, R. and W. Donald (1994). Analysis of hydroxylated atrazine degradation products in water using sohd-phase extraction and high-performance hquid chromatography. J. Agric. Food Chem., 42 922-927. 

Figure 22.3 TMn layer chromatograph of (U-ring 14C) atrazine degradation products of pMDl and pMD4.a aThe silica gel plate was developed in chloroform methanohformic acid water (74 20 4 2 v/v). Metabolites were visualized by phosphor imaging.

Lerch, R.N., E.M. Thurman, and E.L. Kruger (1997). Mixed-mode sorption of hydroxylated atrazine degradation products to soil A mechanism for bound residue. Environ. Sci. Technol., 31 1539-1546. 

Sorenson, B.A., D.L. Wyse, W.C. Koskinen, D.D. Buhler, W.E. Lueschen, and M.D. Jorgenson (1993). Formation and movement of 14C-atrazine degradation products in a sandy loam soil under field conditions. Weed Sci., 41 239-245. 

During 1991, water-quality samples were analyzed from a network of 303 wells across 12 states, while a subset of the 303 wells was sampled from 1992 to 1994 (Kolpin and Burkart, 1991 Kolpin et al., 1993, 1994,1995, 1996, 1997, 1998, 2000) (Figure 30.3A). Atrazine was detected in samples from 22.4% of the 303 wells (Table 30.1). Two atrazine degradation products, DEA and DIA, also were some of the most frequently detected compounds in these studies. The trend, as shown by the frequencies of detection, reflects the relative stability of these compounds. 

An important finding of USGS research was the occurrence of triazine herbicides in surface water. In a study by Thurman et al. (1991, 1994) measurable amounts of atrazine, the most frequently detected herbicide, occurred in 91% of the pre-planting samples, 98% of the post-planting samples, and 76% of the harvest samples. The atrazine degradation product DEA was found in many of the samples that contained atrazine. The frequency of detection or apparent order of stability of the herbicides and their degradation products is as follows atrazine, DEA, DIA, and cyanazine. This stability order is based on results of field-dissipation studies on atrazine and cyanazine (Meyer, 1994 Mills and Thurman, 1994). 

Lerch, R. N., Donald, W. W., Li, Y.-X., and Alberts, E. E., Hydroxylated atrazine degradation products in a small Missouri stream, Ch 19, In Herbicide Metabolites in Surface Water and Groundwater, Meyer, M. T. and Thurmann, E. M. Eds., American Chemical Society Symposium Series, p. 318, 1996. 

In a soil-core microcosm study, Winkelmann and Klaine (1991) observed that the concentration of atrazine decreased exponentially over a 6-month period. Metabolites identified in soil included DEA, deisopropylatrazine, DAA and hydroxyatrazine. The half-life in soil is 71 days (Jury et al., 1987). Under laboratory conditions, the half-lives for atrazine in a Hatzenbiihl soil (pH 4.8) and Neuhofen soil (pH 6.5) at 22°C were 53 and 113 days, respectively (Burkhatd and Guth, 1981). Atrazine degradation products identified in soil were deethylatrazine, deisopropylatrazine, deethyldeisopropylatrazine and hydroxyatrazine (Patumi et al., 1981). Microbial attack of atrazine gave deethylated atrazine and deisopropyl atrazine as major and minor metabolites, respectively (Sirons et al., 1973). 

Figure 3.30 TIC trace obtained from the LC-MS analysis of atrazine and its degradation products. Reprinted from J. Chromatogr., A, 915, Steen, R. 1. C. A., Bobeldijk, I. and Brinkman, U. A. Th., Screening for transformation products of pesticides using tandem mass spectrometric scan modes , 129-137, Copyright (2001), with permission from Elsevier Science.

The TIC trace from the LC-MS analysis of an extracted river water sample, spiked with 3 p.g dm of atrazine and three of its degradation products, is shown in Figure 3.30. The presence of significant levels of background makes confirmation of the presence of any materials related to atrazine very difficult. The TIC traces from the constant-neutral-loss scan for 42 Da and the precursor-ion scan for m/z 68 are shown in Figure 3.31 and allow the signals from the target compounds to be located readily. 

Acero JL, K Stemmier, U van Gunten (2000) Degradation kinetics of atrazine and its degradation products with ozone and OH radicals a predictive tool for drinking water treatment. Environ Sci Technol 34 591-597. 

Jones, T.W. and L. Winchell. 1984. Uptake and photosynthetic inhibition by atrazine and its degradation products on four species of submerged vascular plants. Jour. Environ. Qual. 13 243-247. 

Stratton, G.W. 1984. Effects of the herbicide atrazine and its degradation products, alone and in combination, on phototrophic microorganisms. Arch. Environ. Contam. Toxicol. 13 35-42. 

The LLE of relatively polar and water-soluble organic compounds is, in general, difficult. The recovery obtained from 11 of water with dichloromethane is 90% for Atrazine but lower for its more polar, degradation products, i.e., di-isopropyl- (16%), di-ethyl- (46%),andhydroxy-atrazine (46%). By carrying out LLE with a mixture of dichloromethane and ethyl acetate with 0.2 mol/1 ammonium formate, the extraction recoveries for the three degradation products were increased to 62 %, 87 %, and 65 %, respectively [437]. 

A facultative anaerobic bacterium isolated from a stream sediment utilized atrazine as a carbon and nutrient source. Microbial growth was observed but no degradation products were isolated. At 30 °C, the half-life was estimated to be 7 d (Jessee et ah, 1983). 

Surface Water. Desethyl- and desisopropylatrazine were degradation products of atrazine identified in the Mississippi River and its tributaries (Pereira and Rostad, 1990). Under laboratory conditions, atrazine in distilled water and river water was completely degraded after 21.3 and 7.3 h, respectively (Mansour et al., 1989). 

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