Simazine Document

Groundwater contamination by agrochemicals from non-point sources has been well documented in a number of countries [26-28, 30-32], The pesticides that have been detected in regional council groundwater surveys include 2,4-D, Amitrole, Picloram, Simazine and Atrazine [20]. 

Triazines were one of the first family of herbicides where weed resistance was widely recognized and documented in the literature. A simazine-resistant biotype of common groundsel was identified in Washington, United States, in 1968. Since then biotypes of at least 66 triazine-resistant weed species have been reported, mostly in the United States, Canada, and Europe (Heap, 2006). 

Ciba Crop Protection (1995). Atrazine/simazine response to the United States Environmental Protection Agency s Position Document 1 Initiation of Special Review November 23, 1994. Submitted to USEPA. Public Docket OPP-30000-60. 

During late 1994, the United States Environmental Protection Agency (USEPA) published a public document (PD-1) relative to the use of triazine herbicides by American farmers. In doing so, they placed atrazine and simazine in Special Review. USEPA s PD-1 triggered a benefits study of unprecedented proportions on the following issues benefits of atrazine and simazine use economic and biological impact of the loss of these products feasibility and efficacy of alternatives environmental benefits associated with atrazine and simazine use best management practices and comparative performance of alternatives. 

Breckenridge, C. (1996a). Summary of Additional Comments on the Response to the Special Review Position Document 1 for Pesticide Products Containing Atrazine and Simazine. Supplement 1. Submitted to USEPA. 

Selman, F. (1996b). A Revised Assessment of Worker Exposure For Simazine in Response to the USEPA Issuance of the Triazine Herbicides Position Document 1 Initiation of Special Review. Submitted to USEPA. 

These landmarks in American agriculture, and many others dated from before 1600 to 1990, are documented by Smith and Roth (1990). In 1958 and 1959 another major milestone in com production was attained when the triazine herbicides (simazine and atrazine) were registered for weed control in com. 

Clarkson, J.R. (1996). Human Exposure to Atrazine and Simazine via Ground and Surface Drinking Water Update 1 (Submission by Ciba Crop Protection, Ciba-Geigy Corporation (now Syngenta Crop Protection, Inc.), Atrazine/Simazine Atrazine/Simazine Response to the United States Environmental Protection Agency s Position Document 1 Initiation of Special Review (November 23, 1994) Public Docket OPP-30000-60), Montgomery Watson, Wayzata, MN, USA. 

The documented occurrence of pesticides in surface water is indicative that runoff is an important pathway for transport of pesticide away from the site of appHcation. An estimated 160 t of atrazine, 71 t of simazine, 56 t of metolachlor, and 181 of alachlor enter the Gulf of Mexico from the Mississippi River annually as the result of mnoff (47). Field appHcation of pesticides inevitably leads to pesticide contamination of surface runoff water unless runoff does not occur while pesticide residues remain on the surface of the soil. The amount of pesticides transported in a field in runoff varies from site to site. It is controlled by the timing of mnoff events, pesticide formulation, physical—chemical properties of the pesticide, and properties of the soil surface (48). Under worst-case conditions, 10% or more of the appHed pesticide can leave the edge of the field where it was appHed. 

The electrochemistry of triazines is well documented.Polak and Volke described a dpp procedure for the determination of symmetrical and asymmetrical triazines (desmetryne, methoprotryne, prometryne, aziprotryne, terbutryne, atrazine, cyanazine, simazine, terbuty-lazine, metribuzine) in water. The herbicides are extracted into chloroform from the sample at pH 8 to 9. The detection limit in 0.02 M H2SO4 or acetic acid buffered solution at pH 2.5 is given as 10 M. 

---