Estudio comparativo del impacto ambiental de tres herbicidas de uso comun en cultivos de soja y trigo

R. C. PESSAGNO; M. DOS SANTOS AFONSO

Medioambiente en Iberoamérica. Visión desde la Física y la Química en los albores del siglo XXI

SiFyQA

Año: 2006; p. 345 - 352

The herbicides of the sulfonylurea family are largely used for the control of broadleaf weeds in crops.   The application of persistent herbicides alone or in combination qith Glyphosate is a common practice in our region.  One of the most outstanding characteristics of sulfonylureas is their moderate to high residually in the soil.  Chlorsulfuron, chlorimuron-ethyl, metsulfuron-methyl among others belong to this group.Chlorimuron-ethyl controls broadleaf weeds in soybean while the metsulfuron-methyl is used for barley, oats, wheat and broadleaf control in non cultivated areas.  The deposition in soils, the runoffs, the adsorption processes and leached contribute to the contamination of the freshwaters and groundwaters being the hydrolysis one of the more important processes of these herbicides dissipationin the natural waters.  Glyphosate (N-phosphonomethylglycine) is one of the mores spread herbicides along the world.   This herbicide is non selective, post emergent and of wide spectrum.  In this work we show a comparative study of the environmental impact of th three herbicides: chlorimuron, metsulfuron and glyphosate.The reaction products at different pH were determined by GC-MS, ICP and/or IC.  To determine the permeation of the herbicides and their degradation products assays in packed columns with soils were carried out at controlled pH, temperature and humidty.  The permeation processes and degradation of these compounds were interpreted in function of their different molecular structures and chemical properties