O objetivo deste trabalho foi avaliar a relação entre o consumo de água pelas plantas de cana-de-açúcar e plantas daninhas e a absorção de herbicidas. O trabalho foi desenvolvido em dois experimentos: no primeiro, mediu-se o consumo de água através da pesagem diária das espécies de plantas daninhas Digitaria horizontalis, Panicum maximum, Ipomoea grandifolia, Ipomoea hederifolia, Brachiaria decumbens, assim como para os cultivares de cana-deaçúcar PO8862, SP80 3280 e RB83 5486; e, no segundo, foram determinadas as concentrações do amicarbazone, imazapic, tebuthiuron e hexazinone no xilema dos três cultivares de cana-deaçúcar e de I. grandifolia por meio da bomba de Schollander e de cromatografia e espectrometria de massas (LC-MS). A taxa de transpiração e, consequentemente, a taxa de consumo de água mostraram-se determinantes da taxa de absorção de herbicidas pelas plantas de diferentes espécies de plantas daninhas e cultivares de cana-de-açúcar. As concentrações de herbicidas na seiva do xilema foram variáveis em função da espécie e do herbicida em contato com o sistema radicular, indicando que a facilidade de absorção pelas raízes pode ser determinante para eficácia e/ou seletividade de herbicidas.<br>The objective of this work was to evaluate the relationship between water consumption by sugarcane plants and weeds and herbicide absorption. Two experiments were carried out. In the first, water consumption was measured by daily weighing the weed species Digitaria horizontalis, Panicum maximum, Ipomoea grandifolia, Ipomoea hederifolia, Brachiaria decumbens, as well as the sugarcane cultivars PO8862, SP80 3280, and RB83 5486. In the second experiment, the concentrations of amicarbazone, imazapic, tebuthiuron and hexazinone in the xylem of the three sugarcane cultivars and I. grandifolia were measured using the Schollander pump and chromatography and mass spectrometry (LC MS). The transpiration rate and, consequently, the water consumption rate were determinants of the rate of herbicide absorption by the different weed species and sugarcane cultivars. The herbicide concentrations in the xylem sap varied according to the species and herbicide in contact with the root system, indicating that easy absorption by the roots can be crucial to the effectiveness and/or selectivity of herbicides.

[EN]Este trabajo se centra en el estudio de la degradación de los edulcorantes sucralosa (SUC), aspartamo (ASP) y sacarina (SAC) en agua mediante radiación ultravioleta. La degradación se monitorizó mediante un equipo de cromatografía de líquidos/espectrometría de masas con analizador de tiempo de vuelo (HPLC-TOFMS). También se evaluó la presencia y formación de diferentes productos de degradación. Los resultados muestran que, en el caso de sucralosa, se degrada completamente a las 7 horas de exposición a la radiación y muestra un producto de degradación (Peso Molecular (Pm): 358). El aspartamo se degrada completamente a las 3 horas de exposición encontrándose dos productos de degradación (Pm: 206 y 262). En el caso de la sacarina, esta se degrada parcialmente, hasta un 60% durante las 4 horas de exposición, originándose al menos 8 productos de degradación con Pm: 214 (4 isómeros) y 198 (4 isómeros). | [EN]This work is focused on the study of the degradation of the sweeteners sucralose (SUC), aspartame (ASP) and saccharin (SAC) in water by ultraviolet irradiation. The degradation was monitored using Liquid Chromatography/ Time-of-Flight Mass Spectrometry (HPLC-TOF-MS). Different degradation products were also analyzed. The results show that, sucralose is completely degraded after 7 hours of radiation exposure, being a degradation product (Mw: 358) identified. Aspartame is completely degraded after 3 hours of irradiation being 2 degradation products detected (Mw: 206 and 262). Finally, saccharin was partially degraded to 60% and the HPLC-TOFMS analyses revealed the generation of 8 degradation products with Mw 214 (4 isomers) and 198 (4 isomers).

[ES]En el presente trabajo de fin de grado, se ha estudiado el comportamiento de dos antimicrobianos (triclosán y triclocarbán) empleados en numerosos productos comerciales frente al tratamiento con radiación ultravioleta (UV) para su degradación, estudiando además la posible formación de productos de degradación y su persistencia al tratamiento. Para ello, el método analítico empleado es HPLC-MS ya que según los estudios previos es uno de los más eficaces para la determinación de estos compuestos. Se encontró que el triclosán se degradaba con facilidad, alcanzándose la degradación completa a los 10 minutos de exposición. Sin embargo el triclocarbán a los 120 minutos de exposición alcanza el 50% de su degradación, siendo la degradación completa a los 250 minutos. Por lo que respecta a la formación de n productos de transformación, se han podido identificar hasta 12 productos de transformación del Triclosán y 25 del triclocarbán siendo la mayoría de ellos de rápida formación y degradación, por lo que se eliminan rápidamente del medio. | [EN]In this work, the degradation of two antimicrobials (triclosan and triclocarban) with ultraviolet (UV) irradiation treatment has been studied. For this purpose, HPLC-MS was used for the monitoring of triclosan and triclocarban degradation as well as for the identification of transformation products. It was found that triclosan was easily degraded, reaching the complete degradation within 10 minutes of exposure. In contrast, triclocarban only reached 50% of its degradation after 120 minutes of UV exposure, being completely degradaded after 250 minutes. With respect to the formation of transformation products, 12 triclosan transformation products were identified, whille for triclocarban, 25 related species were formed from HPLC-MS data. In all cases, the intermediates identified were completely degraded.

Resumen: La aplicación de productos químicos para el control de plagas es uno de los métodos más usados en la agricultura a nivel mundial a pesar de tener efectos adversos sobre los humanos y el ambiente. Este es un tema de interés por el número creciente de productos químicos y su toxicidad. Los objetivos de esta investigación fueron identificar los plaguicidas más comercializados dentro de la cuenca del río Ayuquila-Armería (México) y determinar su concentración en el agua superficial. La hipótesis de este trabajo fue que el sistema actual de producción agrícola en la cuenca está provocando la degradación de la calidad de agua debido a la presencia de una amplia variedad de plaguicidas. Para el primer objetivo se visitaron 27 expendios de plaguicidas ubicados en las principales cabeceras municipales en la cuenca; obteniéndose un total de 143 ingredientes activos comercializados, principalmente de origen químico. Para el segundo objetivo se realizaron dos muestreos en temporada de estiaje y dos en la de lluvias, en 30 sitios distribuidos en la cuenca. Los sitios de muestreo fueron elegidos de forma dirigida de acuerdo a la problemática de contaminación existente y tratando de cubrir las zonas agrícolas más grandes dentro de la cuenca. Los análisis se hicieron con cromatografía de líquidos acoplada a espectrometría de masas-masas. Los resultados mostraron que el 66% de las muestras presentaron al menos un plaguicida. Los plaguicidas más frecuentes fueron ametrina, dimetoato y diazinón. Los sitios que presentaron mayor número de plaguicidas en los cuatro muestreos fueron Palo Blanco, Antes Manantlán, Tuxcacuesco y Ayuquila. Los sitios cercanos a la zona de agricultura intensiva presentaron número mayor de plaguicidas que aquellos ubicados en zonas con agricultura de secano. Este estudio es el primero en analizar la presencia de plaguicidas en aguas superficiales en la cuenca. | Summary: The application of chemical products for pest control is one of the most widely used methods in agriculture worldwide despite their adverse effects on humans and the environment. This is a topic of interest due to the growing number of chemical products and their toxicity. The objectives of this research were to identify the most commercialized pesticides in the Ayuquila-Armería River basin (Mexico) and to determine their concentration in the surface water of the basin. The hypothesis of this work was that the current system of agricultural production in the basin is causing degradation of water quality due to the presence of a wide variety of pesticides. For the first objective, we visited 27 outlets of pesticides located in the main municipal capitals within the basin, obtaining a total of 143 commercialized active ingredients, mainly of chemical origin. For the second objective, we carried out two samplings in the dry season and two in the rainy season, in 30 sites distributed within the basin. The sampling sites were chosen in a directed way according to the problem of existing contamination and trying to cover the largest agricultural areas within the basin. The analyses were carried out through liquid chromatography coupled to mass-mass spectrometry. The results showed that 66% of the samples contained at least one pesticide. The most frequent pesticides were ametrine, dimethoate and diazinon. The sites that presented the highest number of pesticides in the four samplings were Palo Blanco, Antes Manantlán, Tuxcacuesco and Ayuquila. The sites near the area of intensive agriculture had a higher number of pesticides than those located in areas with rainfed agriculture. This study is the first to analyze the presence of pesticides in surface waters of the basin.

O objetivo deste trabalho foi avaliar a relação entre o consumo de água pelas plantas de cana-de-açúcar e plantas daninhas e a absorção de herbicidas. O trabalho foi desenvolvido em dois experimentos: no primeiro, mediu-se o consumo de água através da pesagem diária das espécies de plantas daninhas Digitaria horizontalis, Panicum maximum, Ipomoea grandifolia, Ipomoea hederifolia, Brachiaria decumbens, assim como para os cultivares de cana-deaçúcar PO8862, SP80 3280 e RB83 5486; e, no segundo, foram determinadas as concentrações do amicarbazone, imazapic, tebuthiuron e hexazinone no xilema dos três cultivares de cana-deaçúcar e de I. grandifolia por meio da bomba de Schollander e de cromatografia e espectrometria de massas (LC-MS). A taxa de transpiração e, consequentemente, a taxa de consumo de água mostraram-se determinantes da taxa de absorção de herbicidas pelas plantas de diferentes espécies de plantas daninhas e cultivares de cana-de-açúcar. As concentrações de herbicidas na seiva do xilema foram variáveis em função da espécie e do herbicida em contato com o sistema radicular, indicando que a facilidade de absorção pelas raízes pode ser determinante para eficácia e/ou seletividade de herbicidas. | The objective of this work was to evaluate the relationship between water consumption by sugarcane plants and weeds and herbicide absorption. Two experiments were carried out. In the first, water consumption was measured by daily weighing the weed species Digitaria horizontalis, Panicum maximum, Ipomoea grandifolia, Ipomoea hederifolia, Brachiaria decumbens, as well as the sugarcane cultivars PO8862, SP80 3280, and RB83 5486. In the second experiment, the concentrations of amicarbazone, imazapic, tebuthiuron and hexazinone in the xylem of the three sugarcane cultivars and I. grandifolia were measured using the Schollander pump and chromatography and mass spectrometry (LC MS). The transpiration rate and, consequently, the water consumption rate were determinants of the rate of herbicide absorption by the different weed species and sugarcane cultivars. The herbicide concentrations in the xylem sap varied according to the species and herbicide in contact with the root system, indicating that easy absorption by the roots can be crucial to the effectiveness and/or selectivity of herbicides.