Esse estudo descreve pela primeira vez o uso do método ASTM D6584 para a determinação de glicerol e glicerídeos em amostras de ésteres etílicos de biodiesel obtidas a partir de óleo de girassol e da mistura de óleo de soja/sebo; e amostras de ésteres metílicos de biodiesel produzidas a partir da mistura de óleo de soja/tungue e de óleo de tungue. Os resultados mostraram que o método ASTM D6584 pode ser empregado para outras fontes de biodiesel, as quais representam uma alternativa para a produção de biodiesel, principalmente no Brasil.

This study describes for the first time the determination of glycerol and glycerides in samples of biodiesel ethyl esters from sunflower oil and soybean/tallow mixture and biodiesel methyl esters from soybean/tung mixture and tung oil by employing ASTM D6584 method. The results showed that ASTM D6584 can be used for other sources of biodiesel which represent an alternative to biodiesel production, mainly in Brazil.

A produção agrícola geralmente está associada ao uso de agrotóxicos. Suas características físico-químicas, condições do solo e do ambiente determinam seu destino, assim como o seu potencial de contaminação dos mananciais hídricos. Com o intuito de prever a contaminação do ambiente por agrotóxicos, critérios e modelos matemáticos são utilizados para avaliar o risco de contaminação das águas subterrâneas e superficiais. Diante do exposto, este trabalho teve por objetivo estimar a probabilidade de contaminação de águas subterrâneas e superficiais por agrotóxicos, baseado nas suas características físico-químicas, com auxílio de modelos e parâmetros matemáticos preexistentes. Para análise do risco de contaminação de águas superficiais, foi utilizado o método de Goss, o qual é dividido em dois grupos: potencial de transporte de agrotóxicos dissolvidos em água e adsorvido ao sedimento. Os critérios utilizados para avaliar o potencial de lixiviação foram os sugeridos pela Agência de Proteção Ambiental dos EUA e pelo Índice de GUS. Os resultados obtidos neste trabalho permitem concluir que o uso de modelos de predição do comportamento de agrotóxicos é útil para se obter uma estimativa do risco de contaminação ambiental, pois alguns resultados de monitoramentos confirmam a tendência do comportamento de certos agrotóxicos no ambiente.

Agricultural production is generally associated with the use of pesticides, their physicochemical characteristics, soil conditions and the environment will determine their fate, as well as the potential for contamination of water bodies. In order to predict environmental contamination by pesticides, parameters and mathematical models are utilized to assess the risk of contamination of groundwater and surface water. For this reason, the objective of this study was estimate the probability of contamination of groundwater and surface waters by pesticides based on their physicochemical characteristics with the aid of preexisting mathematical models and parameters. To analyze the risk of surface water contamination, the Goss method was used, which as composed by two groups: pesticide potential transport dissolved in water and adsorbed to the sediment. The parameter used to evaluate the leaching potential were those suggested by the US Environmental Protection Agency (EPA) and the GUS Index. The results obtained allow to conclude that the use of models to predict the behavior of pesticides is useful to obtain an estimate of the risk of environmental contamination, as some monitoring results confirm the tendency of the behavior of certain products into the environment.

The determination of pesticide residues in water samples by Liquid Chromatography require sample preparation for extraction and enrichment of the analytes with the minimization of interferences to achieve adequate detection limits. The Solid Phase Extraction (SPE), Solid Phase Microextraction (SPME), Stir Bar Sorptive Extraction (SBSE) and Dispersive Liquid-Liquid Microextraction (DLLME) techniques have been widely used for extraction of pesticides in water. In this review, the principles of these sample preparation techniques associated with the analysis by Liquid Chromatography with Diode Array Detection (LC-DAD) or Mass Spectrometry (LC-MS) are described and an overview of several applications were presented and discussed.

This work deals with the method validation for the determination of acetic, propionic and butyric acids (VFAs) in wastewaters from anaerobic reactors by HPLC-DAD. Separation was performed using a C18 column and the mobile phase composition were water pH 3.0 and methanol 90:10 (v/v). The detection and quantification was carried out at 220 nm. The method shows good linearity (r²>0.996), with adequate accuracy (89-102%) and relative standard deviations lower than 18%. The matrix effect was considered low (-4.1, -3.9 and 1.4%). The developed method is fast, simple and cheap; and it was applied in wastewater samples from anaerobic reactor.

The objective this study was to monitor pesticide residues in groundwater at three different times and in seven regions producing rice in southern Brazil, in the 2007/08 season. Imazethapyr and fipronil were found in all regions studied. All groundwater samples from the Planície Costeira Interna to Lagoa dos Patos and Santa Catarina contained at least one pesticide. The lowest number of contaminated samples were detected in the Southern region. The highest frequency of contaminated samples was found after drainage of the rice fields. Only fipronil exceeded limits of potability, in 27% of samples, according European Community criteria.

An evaluation of the pesticides extraction from onion using a modern sample preparation method (QuEChERS) and determination by liquid chromatography tandem mass spectrometry was carried out. All the calibration curves showed r>0.99. The recoveries ranged between 61.8 and 120.0% with relative standard deviation lower than 20% for all compounds. Due to the occurrence of matrix effect, the quantification was performed using matrix-matched calibration. The limits of quantification of the method were between 0.0005 and 0.05 mg kg-1. The method shows the advantages of not require the clean-up step and consume low volume of organic solvents, decreasing time, costs and residues.

A atividade orizícola é conduzida com uso intensivo de agrotóxicos, os quais, dependendo do manejo e das precipitações pluviais, podem chegar até os rios. O objetivo do trabalho foi determinar resíduos dos herbicidas clomazona, quincloraque, propanil, bentazona, 2,4-D e imazethapyr e dos inseticidas carbofurano e fipronil nos rios Vacacaí e Vacacaí-Mirim, situados na Depressão Central do Rio Grande do Sul, nas safras de 2003/04 a 2007/08, com coletas realizadas de novembro a fevereiro (cultivo do arroz). As análises dos herbicidas e do carbofurano foram realizadas por HPLC-DAD, e a análise do fipronil foi realizada por GC-ECD. Na safra 2003/04, em ambos os rios, os herbicidas clomazona, 2,4-D e propanil foram os mais frequentes nas amostras de água. Na safra 2004/05, o quincloraque foi detectado em maior número de amostras, já nas safras 2005/06 e 2006/07 fipronil foi o agrotóxico mais frequente nas amostras nos rios Vacacaí e Vacacaí-Mirim. Na safra de 2007/08, houve menor presença de resíduos de agrotóxicos nos rios Vacacaí e Vacacaí-Mirim. Há presença de agrotóxicos utilizados na lavoura de arroz nos rios Vacacaí e Vacacaí-Mirim durante o período de cultivo de arroz irrigado, destacando-se, entre os analisados, os herbicidas clomazona e quincloraque e o inseticida fipronil.

The rice-growing activity is conducted out with intensive use of agrochemicals, which, depending on the management and rainfall can reach rivers. The study aimed to determine the residues of herbicides clomazone, quinclorac, propanil, bentazone, 2,4-D and imazethapyr and insecticides carbofuran and fipronil in the Vacacaí and Vacacaí-Mirim rivers, located in the Central Depression of Rio Grande do Sul, in the crop of 2003/04 untill 2007/08. Samples were collected from November to February (rice growing season). Analysis of herbicides and carbofuran were performed by HPLC-DAD and fipronil by GC-ECD. During 2003/04, in both rivers, the herbicide clomazone, 2,4-D and propanil were the most frequent in water samples. In 2004/05, the quinclorac was detected in many samples and in 2005/06 and 2006/07 season's fipronil was the most common pesticide in the samples in Vacacaí and Vacacaí-Mirim rivers. In the 2007/08 crop, there were less residues of pesticides in Vacacaí and Vacacaí-Mirim rivers. There is presence of pesticides used in rice farming in the Vacacaí and Vacacaí-Mirim rivers during the rice crop, especially among those analyzed, the herbicides clomazone and quinclorac and the insecticide fipronil.

Pesticides can be quite useful in agricultural production, however, some pesticides after application can reach and contaminate the hydric resource. Pesticide monitoring must be careful because it is expensive and lengthy. Thus, in this work, a theoretical prediction was made using the approaches suggested by EPA-USA, the Groundwater Ubiquity Score index (GUS) and the Goss method associated with physicochemical properties of 27 pesticides used in a region in the south of Brazil. The results of this work led to the identification of the pesticides that should be prioritized in the environmental monitoring due to their high potential for contaminating water resources.

This article presents an evaluation of the pollution of river water by herbicides used in the culture of irrigated rice in Rio Grande do Sul State, Brazil. Firstly, a theoretical evaluation was made using the approaches suggested by EPA-USA, the "Groundwater Ubiquity Score" index and the Goss method to estimate the pollution possibilities. Afterwards, a monitoring program was established for the rivers of the area from 2001 to 2003 to investigate the presence of herbicide residues. The results indicate that the herbicides clomazone and propanil are the ones with larger presence and frequency in the analyzed samples. The theoretical forecast was confirmed by the results of the monitoring program.