Resumo em inglês The synthesis of ten symmetrically and unsymmetrically substituted 1,3,5-triazines by Phase Transfer Catalysis (PTC) method is described. Their toxicities were determined against Artemia salina Leach. The LD50 values have also been obtained for these compounds.
Identificação taxonômica de espécies de capim-colchão infestantes da cultura da cana-de-açúcar no Estado de São Paulo e eficácia de herbicidas no controle de Digitaria nuda/ Taxonomic identification of crabgrass species infesting sugarcane crop in São Paulo State and herbicide efficacy to control Digitaria nuda
Resumo em português O uso contínuo de herbicidas recomendados para o controle de plantas daninhas na cultura da cana-de-açúcar tem imposto pressão de seleção sobre espécies de capim-colchão (Digitaria spp) ocorrentes na cultura da cana-de-açúcar, causando redução das populações suscetíveis e aumentando a proporção de espécies tolerantes desse gênero de plantas daninhas. A fim de avaliar este fenômeno, sob condições de produção de cana no campo, foi desenvolvida esta p (mais) esquisa com os seguintes objetivos: a) avaliar a eficácia de herbicidas utilizados na cultura da cana-de-açúcar no controle da Digitaria nuda em condições de campo e b) identificar as espécies de Digitaria selecionadas em áreas de aplicação repetitiva de herbicidas. No experimento de campo foram utilizados oito tratamentos herbicidas (ametrina, diuron, tebuthiuron, diuron + hexazinone, imazapyr, isoxaflutole, metribuzin e imazapic), aplicados em condições de pré-emergência. As avaliações de controle foram realizadas aos 15, 30 e 60 dias após a aplicação (DAA). A identificação das espécies de Digitaria, foram efetuadas, seguindo chave analítica de identificação, através da observação das caracterí sticas morfológicas das plantas e por meio de consulta a especialista. A espécie D. nuda foi selecionada pela aplicação contínua dos herbicidas utilizados no controle de capim-colchão na cultura da cana-de-açúcar. Essa espécie pode, de maneira geral, ser controlada em níveis abaixo do esperado, pelos herbicidas diuron, tebuthiuron, diuron + hexazinone, imazapyr e imazapic. No entanto, os herbicidas ametrina, isoxaflutole e metribuzin apresentaram boa eficácia de controle até os 60 DAA. Resumo em inglês The continuous use of herbicides from the chemical groups triazines and substituted ureas has imposed a selection pression upon tolerant species of crabgrass (Digitaria spp), in sugarcane plantations, causing the phenomenon of weed species shift, by reducing the populations of susceptible crabgrass species and increasing the proportion of tolerant species of this weed genus. In order to scientifically elucidate this phenomenon, this research was developed, under field con (mais) ditions, with the following objectives: a) to evaluate the agronomic efficacy of herbicides used in sugarcane crops to control D. nuda and b) taxonomic identification of Digitaria species selected by herbicides in areas that received repetitive applications. Eight herbicide treatments (ametryne, diuron, tebuthiuron, diuron + hexazinone, imazapyr, isoxaflutole, metribuzin e imazapic), applied during pre-emergence were used, and control percentage was evaluated at 15, 30 and 60 days after herbicide application (DAA). The identification of species of Digitaria population was carried out following analytical identification key, through the observation of plant morphologic characteristics. The specie D. nuda was selected by herbicide repetitive applications. The specie D. nuda was controlled in a lower level by the herbicides diuron, tebuthiuron, diuron + hexazinone, imazapyr and imazapic. However, the herbicides ametryne, isoxaflutole and metribuzin showed good efficacy to control until 60 DAA.
Resumo em inglês The clay minerals montmorillonite (MT) and vermiculite (VT), previously treated with Ca2+, K+ and Na+, were employed in a sorption study with herbicides. The herbicides 2,4-D, diuron, alachlor and metolachlor showed no interaction with MT and VT. On the other hand, the triazines presented a good sorption process, close to 100% for ametrine removal and near to 56 and 69% for atrazine and simazine, respectively, by MT. These results suggest that the MT specie may be a good (mais) material for triazines removal from aqueous medium and an alternative phase to preconcentration process, besides to exhibit a good selectivity.
Diagnóstico espaço-temporal da ocorrência de herbicidas nas águas superficiais e sedimentos do Rio Corumbataí e principais afluentes/ Spatial-temporal diagnostic of herbicide occurrence in surface waters and sediments of Corumbataí River and main affluents
Resumo em inglês Residues of herbicides from sugarcane were monitored in waters and sediments of Corumbataí River and tributaries. Ametryne, atrazine, simazine, hexazinone, glyphosate, and clomazone were detected in water samples, with negligible levels of ametryne and glyphosate in sediment samples. The area of recharge of the Guarani aquifer presented the highest triazine and clomazone levels. The triazines were detected at higher levels, with atrazine above Brazil's potability and qua (mais) lity standards. Total herbicide levels at some sampling points were 13 times higher than the European Community potability limit. There is no Brazilian standard for ametryne, although the risk is larger due to ametryne's higher toxicity for the aquatic biota.
Resumo em inglês The aromatic six-membered heterocycles having three nitrogen atoms are denominated triazines. Among these heterocycles, isocyanuric chloride and cyanuric chloride are inexpensive and readily available 1,3,5-triazine derivatives, which have been attracting significant attention of organic chemists due to their different kinds of applications, which vary from pharmaceuticals to explosives. This short overview explores their uses in synthetic methods, as chlorinating and oxidating agents and some procedures for their preparation.
Avaliação do impacto da agricultura em áreas de proteção ambiental, pertencentes à bacia hidrográfica do rio ribeira de iguape, São Paulo/ Assessment of the impact of agriculture on environmental preservation aers of the ribeira de iguare river, São Paulo
Resumo em inglês In order to ascertain the impact of agricultural activities on water quality of the Ribeira de Iguape River Basin in the state of São Paulo, surface water areas for catchment and drinking water have been characterized. The sampling period covered March/2002 - February/2003 and January/2004 at 10 different catchment points. SPE-LC-UV/Vis was used to monitor various pesticide classes such as carbamates, triazines and nitroanilines. The results revealed that water quality i (mais) s associated with seasonal variation. Of 152 samples analyzed, only 24% showed the presence of pesticides, particulary during the wet season. High variability in pH, turbidity and color were observed.