Atrazine recommendations

In terrestrial ecosystems, atrazine effectively inhibits photosynthesis in target weeds and can also affect certain sensitive crop plants. Atrazine metabolites are not as phytotoxic as the parent compound. Degradation is usually rapid, although atrazine can persist in soils for more than one growing season. Soil fauna may be adversely affected shortly after initial atrazine application at recommended levels, but long-term population effects on this group are considered negligible. 

Atrazine, a triazlne compound, is extensively used as a selective herbicide on corn and sorghum fields for the control of broadleaf and grassy weeds. Depending on soil properties and climatic effects, its persistence from recommended application rates in north central states may extend well beyond one year and crop injury may result when sensitive species are in the rotation (50). 

Atrazine is the only proven product for control of these six common and economically important broadleaf weed species with ALS-resistant biotypes in com. Product labels for each of the ALS herbicides recommend tank mixtures with atrazine. When used in the corn-soybean rotation, atrazine use in com breaks the continuous use of ALS-inhibitor herbicides and delays the spread of ALS-resistant biotypes. For example, Owen el al., (1995) reported that none of the ALS herbicides controlled ALS-resistant common lambsquarters, but atrazine provided excellent control. Sprague et al. (1997c) reported excellent control with atrazine both preemergence and postemergence on ALS-resistant, cross-resistant, and susceptible biotypes of common waterhemp. 

The widespread application of herbicides in agriculture has resulted in many polluted surface waters. As a result, numerous pesticides/herbicides have been treated in bench-scale laboratory studies with 03/UV/H202 processes during the last 10 years (see Table 10). Among them, many studies focused on the treatment of atrazine and other. v-triazine herbicides (simazine, prop-azine, etc.). Atrazine is a priority pollutant that similar to other individual pesticides has a very low maximum contaminant level (MCL) (0.1 pg L 1 for the European Environmental Commission according to Directive 80/778/ EEC). In some countries atrazine cannot be used but it is still found in many surface waters. In France, for example, atrazine was banned on September 28, 2001. From applied technologies, only carbon adsorption [180] and possibly advanced oxidations can be recommended to remove some of these... 

Silylation and alkylation are other methods of modifying triazines. An HMDS—TMCS mixture was used for the preparation of TMS derivatives [492]. Flint and Aue [493], who evaluated several reagents, recommended performing silylation with the aid of BSTFA by heating at 150°C for 15 min. Under these conditions, hydroxy derivatives of simazine, atrazine and propazine provided one large peak and few by-products, identified as mono-, di- and trisilyl derivatives 10% of OV-17 was used as the stationary phase. 

The 1 1 mixture of 2-(2,4,5-trichlorophenoxy)ethanol (TCPE, 24) and atrazine (Buvinol ) is a selective pre- and postemergence herbicide with a broad range of herbicidal action. Many species of mono- and dicotyledonous weeds are sensitive to it in their various stages of development. Postemergence treatment is recommended in soils with extremely low humus content (below 1 %) because of the hazard of phytotoxicity, and in soils with extremely high humus content because of strong adsorption. 

At 2.5 mg atrazine/kg soil, equivalent to 2 kg/ha in the top 10 cm, field and laboratory studies demonstrated that mortality in arthropod coUembolids Onchiurus apuanicus) was 47% in 60 days however, fecundity was not affected at dose levels up to 5.0 mg/kg soil. It was concluded that atrazine applications at recommended treatment levels had negligible long-term population effects on sensitive species of soil fauna. At 5.0 or 8.0 kg atrazine/ha, all species of soil fauna tested, except some species of nematodes, were adversely affected. One month post-application, population reductions of 65-91% were recorded in protozoans, mites, various insect groups, and collem-bolids at 5.0 kg/ha after 4 months, populations were still depressed by 55-78%. At 8.0 kg atrazine/ha, soil faun populations... 

BW daily for a 60-kg person. Both TRMC estimates are substantially below the proposed limit of 0.0375 mg/kg BW daily. Lifetime exposure to drinking water concentrations of 2.3 (xg atrazine/L poses negligible risk to human health, as judged by the no adverse effect level of 7.5 xg/L when 1% of the allowable daily intake is obtained from this source. Higher allowable concentrations are proposed over short periods 123.0 xg/L for adults and 35.0 jig/L for children, over a 10-day period. The proposed drinking water criterion to protect human health in Western Europe is <0.1 Jig/L. In the United States, it should not exceed 3.0 jig atrazine/L drinking water, although some authorities recommend less than 3.6 jig atrazine/L. 

This is photostable and complete mineralisation was not observed. In some countries restrictions on the use of s-triazines, such as atrazine, have been implemented, while in others, these have even been banned. Atrazine has, however, been detected above the recommended levels (0.1 ppb or pg dm ) throughout Europe and the United States and is considered as a priority toxic substance by the EC. Considerable efforts are being made to eliminate it from water. 

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