COMPORTAMIENTO Y DESTINO AMBIENTAL DE LA ATRAZINA EN EL SUELO:

Abstract

<span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;"><p align="left">En este trabajo se optimizó y validó un método analítico</p><p align="left">que incluyó extracción, limpieza, y determinación cromatográfica</p><p align="left">por HPLC de los compuestos atrazina (AT), deetilatrazina</p><p align="left">(DEA) y deisopropilatrazina (DIA). Se analizaron</p><p align="left">muestras de suelo tomadas de una parcela sembrada comercialmente</p><p align="left">con maíz en el municipio de Saldaña, Tolima, tratada</p><p align="left">con el herbicida atrazina a una dosis de 2,4 Kg i.a/ha.</p><p align="left">No se detectaron los productos de degradación DIA y DEA</p><p align="left">en ninguna de las muestras. AT se encontró a una concentración</p><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left">de 233</p></span></span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left"> </p></span></span><p align="left"><span style="font-size: small; font-family: SymbolMT;"><span style="font-size: small; font-family: SymbolMT;">μ</span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">g/Kg a los 4 días después del tratamiento (ddt),<span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left">de 137,0</p></span></span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left"> </p></span></span></p><p align="left"><span style="font-size: small; font-family: SymbolMT;"><span style="font-size: small; font-family: SymbolMT;">μ</span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">g/Kg a los 37 ddt y de 24,8 </span></span><span style="font-size: small; font-family: SymbolMT;"><span style="font-size: small; font-family: SymbolMT;">μ</span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">g/Kg a los 70 ddt; en<p align="left">el muestreo a los 125 ddt no fue detectada.</p><p align="left">En otro experimento bajo condiciones controladas de</p><p align="left">cámaras de crecimiento, para evaluar el efecto de la temperatura</p><p align="left">y la humedad del suelo en el proceso de degradación</p><p align="left">de la atrazina, se encontró que la temperatura, más</p><p align="left">que la humedad, resultó ser un factor determinante para</p><p align="left">la degradación de este herbicida; así, la degradación del</p><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left">compuesto fue mayor a 30</p></span></span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left"> </p></span></span></p><p align="left"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">o</span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">C que a 20</span></span><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">o</span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">C. Con base en el<p align="left">análisis cromatográfico por HPLC tampoco se detectaron</p><p align="left">los metabolitos DIA y DEA en ninguno de los muestreos.</p><p align="left">Los resultados sugirieron, o que el compuesto parental se</p><p align="left">transformaba (metabolizaba) a otros metabolitos diferentes</p><p align="left">a DIA y DEA, o que existía una fuerte interacción de la</p><p align="left">molécula parental y sus metabolitos con los componentes</p><p align="left">del suelo, lo cual no permitía su extracción y detección</p><p align="left">mediante técnicas analíticas convencionales. Por lo cual,</p><p align="left">se estudió la mineralización, sorción y movilidad de la</p><p align="left">atrazina bajo condiciones de laboratorio utilizando técnicas</p><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left">isotópicas con</p></span></span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left"> </p></span></span></p><p align="left"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">14</span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">C en dos suelos del Municipio de Saldaña.<p align="left">La mineralización se determinó a 25°C en bióetros que</p><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left">contenín suelo tratado con</p></span></span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left"> </p></span></span></p><p align="left"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">14</span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">C-atrazina equivalente a 2,0<p align="left">Kg ia/Ha y pequeños frascos con NaOH para colectar el</p></span></span></p><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><p align="left">14</p></span></span></span><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><p align="left"> </p></span></span><p align="left"><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">CO</span></span><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">2 </span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">producto de la mineralización del herbicida. El </span></span><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">14</span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">CO</span></span><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">2</span></span></p><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;"><p align="left">se colectaba semanalmente y se leía su actividad en un contador</p><p>de centelleo. Los suelos estudiados presentaron una <span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;"><p align="left">HPLC procedure DIA and DEA was not detected in any</p><p align="left">of soil samples. Results suggest that parental compound</p><p align="left">was transformed to other metabolites different to DIA or</p><p align="left">DEA, or that a strong interaction of atrazine and their</p><p align="left">metabolites with soil components happens, which did</p><p align="left">not allow compounds extraction and detection by means</p><p align="left">of HPLC procedures. In a third phase, herbicide mineralization,</p><p align="left">sortion and mobility was studied under laboratory</p><p align="left">conditions using isotopic techniques in two soils of</p><p align="left">Saldaña Municipality. Mineralization was determined at</p><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left">25°C in biomethers contained soil treated with</p></span></span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left"> </p></span></span></p><p align="left"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">14</span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">C-atrazine<p align="left">equivalent to a dose of 2,0 Kg ai/Ha and small flasks</p><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left">with NaOH to collect the</p></span></span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left"> </p></span></span></p><p align="left"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">14</span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">CO</span></span><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">2 </span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">resulting of </span></span><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">14</span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">C-atrazine<span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left">mineralization.</p></span></span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left"> </p></span></span></p><p align="left"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">14</span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">CO</span></span><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">2 </span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">was collected weekly and their<p align="left">activity was read by liquid scintillation counting. No</p><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left">more than 11% of</p></span></span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left"> </p></span></span></p><p align="left"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">14</span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">C-atrazine was transformed to </span></span><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">14</span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">CO</span></span><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">2</span></span></p><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left">during 17 weeks period.</p></span></span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left"> </p></span></span><p align="left"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">14</span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">C remained in bound form<p align="left">(49% to 80%), and this bound portion increased with</p><p align="left">the time. Extractable fraction was composed in a 62%</p><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left">to 94% by</p></span></span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left"> </p></span></span></p><p align="left"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">14</span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">C-atrazine and in 6% to 38% by hidroxiatrazine.<p align="left">There was not found any other metabolite. Soils had</p><p align="left">high affinity for the herbicide, and adsorption as the desorption</p><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left">were adjusted to Freundlich model. K</p></span></span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;"><p align="left"> </p></span></span></p><p align="left"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;">d </span></span><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">adsorption<p align="left">values were 0,61 and 0,14 for the two soils, respectively.</p></span></span></p><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-size: xx-small; font-family: TimesNewRomanPSMT;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><p align="left">14</p></span></span></span><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><p align="left"> </p></span></span><p align="left"><span style="font-size: small; font-family: TimesNewRomanPSMT;"><span style="font-size: small; font-family: TimesNewRomanPSMT;">C-atrazina mobility was evaluated by means of Soil<p align="left">Thin Layer Cromatography (STLC); herbicide mobility</p><p>was higher in the sandy-loam than in the silty-loam soil</p></span></span></p></span></span>

Keywords

• Herbicides, atrazine, metabolites, mineralization,