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| Registros recuperados: 10 | |
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| QUEIROZ, R. H. C.; LANCHOTE, V. L.; BONATO, P. S.; TOZZATO, E.; CARVALHO, D. de; GOMES, M. A.; CERDEIRA, A. L.. |
| A simple, rapid, and quantitative bioassay method was compared to a gas chromotography/mass spectrometry (GC/MS) procedure for the analysis of ametryn in surface and groundwater. This method was based on the activity of ametryn in inhibiting the growth of the primary root and shoot of germinating lettuce, Lactuca sativa L. seed. The procedure was sensitive to 0.01 ug/l and was applicable from this concentration up to 0.6 ug/l. Initial surface sterilization of the seed selection of pregerminated seed of certain root lengths, and special equipment are not necessary. So, we concluded that the sensitivity of the bioassay method is compatible with the chromatographic method (GC-MS). However, the study of the correlation between methods suggests that the... |
| Tipo: Artigo de periódico |
Palavras-chave: Persistance; Beneficial effects; Contamination; Water samples; Method; Persistent; Movement; Watershed; Environment; Herbicides; Leaching; Monitoring; Toxicity. |
| Ano: 1999 |
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/13134 |
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| SANTOS, N. A. G.; LANCHOTE, V. L.; DREOSSI, S. A. C.; GOMES, M. A. F.; CERDEIRA, A. L.; CARVALHO, D.; BONATO, P. S.. |
| The extensive use of chlorotriazines as selective herbicides in agriculture and their relatively high persistence imply that these compounds are now present in the environment, contaminating surface and groundwater. In European countries, United States and Canada, the drinking water ordinance demands a limited concentration of 0.5 ug/l for the sum of all pesticides and 0.1 ug/l with respect to each compound, with the consequent need for sensitive and selective analytical methods. Gas chromatography-mass spectrometry (GC-MS) is the most reliable technique for this kind of analysis and was employed in the present study to evaluate the contamination of aqueous environmental samples by atrazine, simazine and ametryne. Surface water samples (1 liter) were... |
| Tipo: Artigo de periódico |
Palavras-chave: GC-MS; Chlorotriazines. |
| Ano: 1997 |
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/12896 |
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| DREOSSI, S. A. C.; LANCHOTE, V. L.; SANTOS, N. A. G.; CERDEIRA, A. L.; GOMES, M. A. F.; CARVALHO, D.; BONATO, P. S.. |
| Substituted phenylureas are selective herbicides used extensively in agriculture and are fairly persistent in the aquatic environment. This has led to the development of many analytical procedures based on high performance liquid cromatography or gas chromatography for determining phenylurea residues in aqueous samples. Although HPLC methods have the advantage of requiring no derivatization, gas chromatography methods seem to be more convenient when coupled to the mass espectrometer detector by providing the reliable of the presence of the herbicide. This technique was employed in the present study to investigate the presence of tebuthiuron residues in 40 aqueous environmental samples collected over a period of ten months (10/95 to 07/96) from the Espraido... |
| Tipo: Artigo de periódico |
Palavras-chave: GC-MS.; Tebuthiuron.. |
| Ano: 1997 |
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/12762 |
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| CERDEIRA, A. L.; GOMES, M. A. F.; QUEIROZ, R. C.; BONATO, P. S.; FERRACINI, V. L.; LANCHOTE, V. L.. |
| Various studies have demonstrated the presence at high levels of pesticides and nitrate in soil, surface, and groundwater. Prior studies have identified a watershed area in Brazil with a high risk of soil, surface, and groundwater contamination by pesticides at the region of Riberao Preto, SP. Surface and groundwater were collected at the area during the period of October 1995 to November 1998. By means of gas chromatography-mass spectrometry (GC-MS) technique the herbicides tebuthiuron, diuron, simazine, atrazine, and ametryne, and nitrate were analyzed according to the protocols established in literature. The recovery obtained in the extraction procedure was higher than 95% for all herbicides except simazine for which the recovery was 85,6%. Due to the... |
| Tipo: Fôlder / Folheto / Cartilha (INFOTECA-E) |
Palavras-chave: Herbicide; Nitrate; Herbicidas; Nitrato de resíduos; Sugarcane. |
| Ano: 1999 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/13142 |
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| BONATO, P. S.; LANCHOTE, V. L.; DREOSSI, A. de C.. |
| Tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N-dimethylurea) is a phenylurea herbicide used in sugar cane culture for the pre- and post-emergence control of weeds [1,2]. Analysis of tebuthiuron (Figure 1) and of other phenylurea herbicides in environmental samples can be performed by HPLC [3-10], or by gas chromatography using selective detectors such as nitrogen-prosphorus detector (NPD), eletron-capture detector (ECD), or a mass spectrometer (MS) [11-16]. Although Loh et al [17] reported that the use of temperatures above 280oC permits quantitative tebuthiuron breakdown, thus permitting the analysis of the products of decomposition formed, methods based on gas chromatography usually involve a derivatization step to permit analysis of... |
| Tipo: Fôlder / Folheto / Cartilha (INFOTECA-E) |
Palavras-chave: Analysis; Contamination; Residues; Calibration; Environmental impact; Groundwater; Herbicides; Quality control. |
| Ano: 1999 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/13136 |
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| TOZZATO, E.; BONATO, P. S.; CERDEIRA, A. L.; GOMES, M. A. F.; CARVALHO, D.; LANCHOTE, V. L.; QUEIROZ, R. H. C.. |
| The beneficial effects of herbicides are sometimes mitigated by their persistence in the environment. Water may be contaminated with herbicides from aerial spraying, runoff from land treated with herbicides, and direct introduction of herbicides into water to control aquatic weeds. The availability of a monitoring system for herbicides, particularly in flowing wates such as irrigation canals is essential so that damage to the environment and crop plants through the use of contaminated water can ve avoided. Therefore, a simple and rapid quantitative method is presented for the screening and determination of small amounts of ametryne in aqueous solution. This method is based on the activity of the ametryne in inhibition the growth of the primary root and... |
| Tipo: Artigo de periódico |
Palavras-chave: Ametryne; Método de bioensaio. |
| Ano: 1997 |
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/12761 |
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| SANTOS, N. A. G.; BONATO, P. S.; DREOSSI, S. A. C.; GOMES, M. A. F.; CERDEIRA, A. L.; CARVALHO, D.; LANCHOTE, V. L.. |
| The high standards for drinking water purity laid down by the European Community, United States and other coutries require the development of suitable analytical methods with high sensitivity, selectivity, accuracy and reliability, that permit the analysis of a broad variety of substances in a single run, or at least those substances that are important in a specific water catchment area. The standard method for the investigation of environmental pollutants has been gas chromatography using different selective detectors after extraction with different organic solvents. Some of that substances that are difficult to analyze by gas chromatography because of thermal instability or chemical polarity, may be analyzed by high performance liquid chromatography. In... |
| Tipo: Artigo de periódico |
Palavras-chave: Multiresidue method; Surface and groundwater; Analysis of herbicides. |
| Ano: 1997 |
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/12895 |
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| SANTOS, A. C.; LANCHOTE, V. L.; BONATO, P. S.; QUEIROZ, R. H. C.; SANTOS, N. A. G.; CERDEIRA, A. L.; CARVALHO, D.. |
| O 2,4 D apresenta moderada solubilidade em água, media solubilidade nos solos e portanto constitui um herbicida com potencial risco de contaminação das águas. De acordo com os padrões de qualidade da água, estabelecidos pelos Estados Unidos e Canada, a Concentração Máxima Tolerada de 2,4 D e de 100 ug/l. Com o objetivo de implantar um programa de monitoramento das águas das regiões de Ribeirão Preto, Serrana e Guaíra, foi desenvolvido um método de analise do 2,4 D em água utilizando a cromatografia em fase gasosa com detector por captura de elétrons. UM volume de 100 ml de água, hidrolisado durante 1 hora em meio alcalino, foi acidificado e extraido com três porcões de 5 ml de diclorometano. Após evaporação das fases orgânicas, o 2,4 D e padrão interno... |
| Tipo: Separatas |
Palavras-chave: 2; 4 D.; Água; Cromatografia Gasosa; Contaminação; Herbicida; Resíduo; Toxicologia.. |
| Ano: 1993 |
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/10957 |
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| CERDEIRA, A. L.; PESSOA, M. C. P. Y.; BONATO, P. S.; QUEIROZ, R. H. C.; LANCHOTE, V. L.. |
| A região de Ribeirão Preto, SP, Brasil, é abastecida com água proveniente de mananciais subterrâneos advindos do aqüífero Guarani, importante lençol de água subterrânea da região centro-sul do país. Na microbacia do Córrego do Espraiado, localizado nesta região, encontra-se um dos pontos de recarga desse aqüífero. Nesse local, com predomínio da cultura de cana-de-açúcar e presença de solo arenoso, a água se infiltra para camadas mais profundas do solo podendo lixiviar defensivos aplicados na superfície, tornando-a vulnerável a essa exposição. O herbicida picloram é um dos produtos aplicados na cultura e para tal foi desenvolvido um método de análise de resíduo do herbicida para amostras de água coletadas na microbacia no período de 1996 a 2001. A avaliaçào... |
| Tipo: Separatas |
Palavras-chave: Qualidade de água; Água subterrânea.; Contaminação.. |
| Ano: 2002 |
URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/15542 |
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| Registros recuperados: 10 | |
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