V. L. Ferracini

Monitoramento e avaliação do risco de contaminação por pesticidas em água superficial e subterrânea na região de Guaíra

The objective of this work was to determine the level of occurrence of pesticides in water, with the purpose of preserving from contamination risk by these pesticides the potable water of the region of Guaira, SP, Brazil. Preliminary hypothesis was that the intensive use of pesticide in the Guaira region is an important factor in the potential contamination of the surface water and groundwater. To identify physical properties and water dynamics in soil, the Fazenda Macauba was selected because of its soil and topography typical of the region. About 80% of the soil of the farm is Oxisol. The plowed layer of the soil has no natural structure and below it there is a compacted layer, both of which derived from agricultural activities. With the goal to evaluate the risk of contamination, the Jardim river, one of its tributary and the groundwater of the Guarani Aquifer were monitored for 2.5 years. The pesticides which were used for the irrigation activities (trifluralin, endosulfan, lambda cyhalothrin, dicofol (4,4 dichlorobenzofenone), captan, parathionmethyl, chlorothalonil and chlorpyriphos) were searched for. Water was analyzed by multiresidue method and the results of this study showed that there is not contamination, except by direct of the surface water. The absence of water contamination is interpreted in relation to the structural characteristics of the soils like thickness, grain size, and field capacity.

Antifungal terpenoids from Chenopodium ambrosioides.

Abstract Two monoterpenes with antifungal activity were isolated from Chenopodium ambrosioides . Structures were elucidated by spectroscopic methods.

Studies on degradation of glyphosate by several oxidative chemical processes: Ozonation, photolysis and heterogeneous photocatalysis

Several different Advanced Oxidation Processes (AOPs) including ozonation at pH 6.5 and 10, photolysis and heterogeneous photocatalysis using TiO2 as semiconductor and dissolved oxygen as electron acceptor were applied to study the degradation of glyphosate (N-phosphonomethyl glycine) in water. The degree of glyphosate degradation, the reactions kinetic and the formation of the major metabolite, aminomethyl phosphonic acid (AMPA), were evaluated. Ozonation at pH 10 resulted in the maximum mineralization of glyphosate. It was observed that under the experimental conditions used in this study the degradation of glyphosate followed the first-order kinetics. The half-life obtained for glyphosate degradation in the O3/pH 10 process was 1.8 minutes.

Three new oxygenated cadinanes from Baccharis species

Abstract Synthesis of several (±)-[4S-(4β,4aβ,8aα)]-1,6-dimethyl-4-(1 methylethyl)-1,2,3,4,5,8,8a-octahydro-1-naphthalenol derivatives (cadinanol derivatives) provided the necessary evidence for the identification of three novel cadinane derivatives [(±)-[1S-(1β, 4β, 4aβ, 8aα)]-1,6-dimethyl-4-(1-methylethyl)-1,2,3,4,4a,5,8,8a-octahydro-1-naphthalenol 11a, (±)-[1S-(1β, 4β, 4aβ, 4aβ, 6α, 7α, 8aα)]-6, 7-epoxide-1,6-dimethyl-4-(1-methylethyl)-1,2,3,4,4a,5,6,7,8,8a-decahydro-1- naphthalenol 14 and (±)-[1S-(1β,4β,4aβ,6β,8aα)]-1,6-dimethyl-4-(1-methylethyl-1,2,3,4,4a,5,6,7,8,8a-decahydro-1,6-naphthalenediol 15] detected, in the essential oils of, B. platipoda. Compound 14 was also detected in B. tridentata. The synthetic compounds were characterized by one and two dimensional 1H and 13C NMR. The identification was obtained by coinjection of the oils with the synthetic standards and fragmentation pattern comparison.

Comportamento do herbicida hexazinone em área de recarga do aqüífero Guarani cultivada com cana-de-açúcar

Sao Paulo state (Brazil) has an important area of sugarcane production, mainly for obtaining alcohol and sugar, where there is an intensive use of pesticides. An important recharge zone of Guarani aquifer, with supplies water for the local population, is located at Ribeirao Preto city, so the local behavior of pesticides must be investigated. The GUS index was obtained by using the paramenters Koc and half-life for hezazinone herbicide, determinated in representative soil of this region. This study has demonstrated that there is potential risks of hexazinone leaching to ground water, indicating that this herbicide must be monitored in ground water.

Leaching and half-life of the herbicide tebuthiuron on a recharge area of Guarany aquifer in sugarcane fields in Brazil

This study was undertaken to evaluate the degradation and mobility of the herbicide tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimethylurea) in soil under field conditions, and its potential for leaching and groundwater contamination. A watershed, Espraiado, located over a recharge area in Brazil, was chosen for soil and water studies. At Espraiado, water samples were collected from seven wells at intervals of three months from March 2004 to June 2006 and analyzed for tebuthiuron. Other samples were taken from city wells located outside of the recharge area. To assess the potential movement to the aquifer, tebuthiuron was also applied to trial plots at the recommended label rate of 1.0 kg/ha a.i. in May of 2004, with and without sugarcane coverage, on sandy soil. Soil samples were collected during the years of 2004 and 2005, at depths intervals of 20 cm from soil surface down to 120 cm and analyzed for tebuthiuron at zero, 3, 30, 60, 90, 120, 150, 180, 240, and 300 days after application. There was no clear effect of sugarcane coverage on the tebuthiuron degradation in soils, but it moved faster into the soil where there was no cover. After 180 days there were no measurable residues in the soil, and tebuthiuron was not found below 40 cm depth in any time. Tebuthiuron had a half-life of 20 days under those conditions. No tebuthiuron residue was found in ground water samples at any sampling time.

ADSORÇÃO E LIXIVIAÇÃO DE TEBUTHIURON EM TRÊS TIPOS DE SOLO

Tebuthiuron adsorption was determined in samples from 0-10 to 10-20 cm layers of three soils from the county of Ribeirao Preto (SP)-Brazil: Quartzarenic Neosol (Entisol), Red Latosol dystrofic and Red Latosol dystroferric (Oxisols). Sorption data were obtained by batch equilibrium and fitted to four adsorption models: Freundlich, linear, Langmuir and Lambert. Several statistical criteria were applied for selection among these isotherms. Freundlich model showed the best fit to the data. Kd values ranged from 0.723 to 2.573 L kg-1, and were correlated to organic carbon (OC) and clay content; KOC values ranged from 135.4 to 374.3 L kg-1. Tebuthiuron mobility was evaluated in soil-packed columns under laboratory conditions and detected at the depths of 60 cm in the Quartzarenic Neosol, 20 cm in the Red Latosol dystrofic and 10 cm in the Red Latosol dystroferric, its leaching being inversely related to Kf values.

Bioconcentration factor estimates of polycyclic aromatic hydrocarbons in grains of corn plants cultivated in soils treated with sewage sludge

This study presents a model to simulate the organic substance concentrations in corn grains assuming that the substances in soil solution are absorbed via the transpiration stream by plants growing in soils fertilized with sewage sludge (SS). The model was applied and validated using soil and corn grain samples from a long-term field experiment with six successive yearly applications of SS to the soil. The following polycyclic aromatic hydrocarbons (PAHs) were simulated and evaluated in soil and grain samples: acenaphthene, acenaphthylene, anthracene, benz(a)anthracene, benz(a)pyrene, benz(b)fluoranthene, benz(g,h,i)perylene, benz(k)fluoranthene, chrysene, dibenz(a,h)anthracene, fluoranthene, fluorene, indeno(1,2,3-c,d)pyrene, naphthalene, phenanthrene and pyrene. The PAH bioconcentration factors (BCF) in corn grains ranged from 1.57 to 10.97 L kg(-1). Polycyclic aromatic hydrocarbons with low soil distribution coefficients and high values of transpiration stream concentration factors (TSCF) are more likely to be absorbed by corn plants and accumulated in grains. It was possible to estimate and observe that highly lipophilic PAH molecules (heavy PAHs) show lower accumulative potential in corn grains than the less lipophilic ones (light PAHs). Sewage sludges containing significant concentrations of light PAHs with two, three or four benzene rings should be avoided as fertilizers in alimentary field crops.

Validação de método multirresíduo para determinação de pesticidas em alimentos empregando QuEChERS E UPLC-MS/MS

This paper presents a practical and rapid method which was validated for simultaneous quantification and confirmation of 29 pesticides in fruits and vegetables using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were extracted following the method known as QuEChERS. Using the developed chromatographic conditions, the pesticides can be separated in less than 9 min. Two multiple reaction monitoring (MRM) assays were used for each pesticide. Four representative matrices (lettuce, tomato, apple and grapes) were selected to investigate the effect in recoveries and precision. Typical recoveries ranged from 70-120%, with relative standard deviation (RSDs) lower than 20%.

Método para a determinação de hexazinone e tebutiuron em água

METHOD FOR DETERMINATION OF HEXAZINONE AND TEBUTHIURON IN WATER. This work presents an alternative method for determination of the herbicides tebuthiuron and hexazinone in ground water. The extraction was made with dichloromethane and the analyses by high performance liquid chromatography (HPLC), using reversed-phase column, C-18, mobile phase methanol/water 50:50, v/v, detection and quantification at 247 nm. The following validation parameters were obtained: limit of detection of method 0.02 and 0.03 µg L -1 , limit of quantification of method 0.07 and 0.09 µg L -1 ; linear range limit of quantification of instrument – 300 µg L -1 (r 2 ≥ 0.998); recoveries from 90.3 to 108.2% and 90.3 to 101.6%; intermediary precision (%RSD) < 8 and < 6%, for hexazinone and tebuthiuron, respectively. The method showed to be efficient and reliable for determination of the herbicides in ground water.