Estimativa de risco de contaminação das águas por pesticidas na região sul do estado do RS

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.

Cutinases fúngicas: propriedades e aplicações industriais

Cutinases (EC 3.1.1.74) are also known as cutin hidrolases. These enzymes share catalytic properties of lipases and esterases, presenting a unique feature of being active regardless the presence of an oil-water interface, making them interesting as biocatalysts in several industrial processes involving hydrolysis, esterification and trans-esterification reactions. They are also active in different reaction media, allowing their applications in different areas such as food industry, cosmetics, fine chemicals, pesticide and insecticide degradation, treatment and laundry of fiber textiles and polymer chemistry. The present review describes the characteristics, potential applications and new perspectives for these enzymes.

Análise de resíduos de agrotóxicos em tomates empregando dispersão da matriz em fase sólida (DMFS) e cromatografia gasosa

This work was aimed on optimization of the matrix solid-phase dispersion (MSPD) technique using gas chromatography for analyzing residues of chlorpyriphos, λ-cyhalothrin, cypermethrin and deltamethrin in tomatoes. The results showed that silica was more efficient for the clean up of extracts, but florisil provided the highest recovery rates. A 2³ complete factorial design was carried out to evaluate the absorbent/sample ratio, presence of co-column (silica) and ultrasonic bath on the extraction rate. The percentage of extraction of the pesticides chlorpyriphos, λ-cyhalothrin, cypermethrin and deltamethrin were 64.7, 88.3, 99.2 and 89.2%, respectively, with relative standard deviations below 5%.

Efeito de matriz na quantificação de agrotóxicos por cromatografia gasosa

The lack of accuracy of a chromatographic method can be associated with the matrix effect. This effect is observed in pesticide quantification by gas chromatography when the chromatographic signals of standards prepared in solvents are compared with those of the analyte in extracts of complex matrices. In the competition between the matrix components and the pesticides for the active sites of the liner, a larger amount of pesticides is transferred to the column, giving apparent extractions above 100%. In this work, we discuss factors that contribute to the matrix effect and present some attempts to overcome the problem.

Resíduos de agrotóxicos em alimentos: uma preocupação ambiental global - Um enfoque às maçãs

This paper describes the use of pesticides in agriculture. Research has shown that significant quantities of pesticide residues have been found in many types of foods. Thus, an overview is given of pesticide residue determinations in fruits and vegetables, with special attention to apples. The toxicity and the adverse effects possibly caused by the exposure of these compounds are alerting the scientific community to develop studies about the validation of analytical methods for multiresidue pesticide determination in these samples. This review shows that pesticide-residue determination in apples is becoming a very important and challenging issue.

Sorção do inseticida tiametoxam em latossolos sob efeito de fosfato e vinhaça

Little information is available on the behavior of thiamethoxam in soils, whereas many studies show the effect of phosphate and vinasse in soils in Brazil. This study evaluated the sorption, desorption and retention of thiamethoxam in vinasse- and phosphate-amended samples of a dystrophic Red-Yellow Latosol (LVAd) and a distroferric Red Latosol (LVdf). The LVAd presented higher sorption of thiamethoxam. Phosphate did not affect the sorption or retention and vinasse increased the interaction of the compound with the soil particles, reducing desorption to the soil solution.

Rapid and accurate hplc-dad method for the determination of the herbicide bispyribac-sodium in surface water, and its validation

A new method is described for the determination of the herbicide bispyribac-sodium in surface water, especially from river and irrigated rice water samples. The method involves extraction in solid phase and quantification by high performance liquid chromatography with diode array detection (HPLC-DAD). After optimization of the extraction and separation parameters, the method was validated. The method presented average recoveries of 101.3 and 97.7%, under repeatability and intermediate precision conditions, respectively, with adequate precision (RSD from 0.9 to 7.5%). The method was applied for the determination of bispyribac-sodium in surface water samples with a limit of detection of 0.1 μg L-1.

QuEChERS: um método moderno de preparo de amostra para determinação multirresíduo de pesticidas em alimentos por métodos cromatográficos acoplados à espectrometria de massas

This review attempts to provide an updated overview of the Quick, Easy, Cheap, Effective, Ruged and Safe (QuEChERS) multiresidue extraction method, that involves initial extraction in acetonitrile, an extraction/partition step after the addition of salt, and a cleanup step utilizing dispersive solid phase extraction. QuEChERS method is nowadays the most applied extraction method for the determination of pesticide residues in food samples, providing acceptable recoveries for acidic, neutral and basic pesticides. Several applications for various food matrices (fruits, vegetables, cereals and others) in combination with chromatographic mass spectrometry analysis were presented.

Influência da temperatura, umidade e profundidade do solo na persistência do diurom e sulfato de endossulfam em um solo tropical

The influence of temperature (30 and 40 ºC) and soil humidity (20, 50 and 70% of water holding capacity) on the degradation of the herbicide diurom and the endosulfan metabolite, endosulfan sulfate was studied under laboratory conditions, in different soil layers (0-30, 30-38 and 38-83 cm) of an Oxisol (Yellow Latosol) collected in an agricultural area of Mato Grosso State, Brazil. Endosulfan sulfate was rapidly degraded under lower soil humidity, higher temperature and deeper soil layers. For diurom the opposite was observed as a consequence of its higher water solubility and lower soil sorption coefficient.

Potencialidades do uso de ultrassom na determinação do pesticida carbaril empregando eletrodos de diamante

The potentiality of the use of ultrasound radiation in association with a boron-doped diamond electrode was evaluated on the voltammetric determination of the pesticide carbaryl. Improvements in the sensitivity, limit of detection and reproducibility of the measurements were observed due to both, the enhancement of mass transport and the cleaning of the electrode surface provided by ultrasound. Satisfactory recovery levels for carbaryl in pure water (96-98%) and pineapple juice (89-92%) for quiescent and sonovoltammetric methodologies were obtained. These methodologies can be alternative tools for the analyses of pesticides in fruit samples, mainly the insonated condition that improve the analytical performance and dispense intermediary cleanings of the electrode surface.

Ocorrência de agrotóxicos em águas subterrâneas de áreas adjacentes a lavouras de arroz irrigado

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.

Análise de risco de contaminação de águas superficiais e subterrâneas por pesticidas em municípios do Alto Paranaíba - MG

A preliminary analyses of the possible contamination of surface and groundwater by the active ingredients of the pesticide products used in the areas with intensive agricultural activities of Alto Paranaíba region, MG, Brazil, was carried out. The active ingredients and formulated products most used in the region were identified and their characteristics of environmental importance were presented. The EPA screening criteria, the groundwater ubiquity score (GUS) and the criteria proposed by Goss were used to evaluate which pesticides might contaminate the local waters. Among the active ingredients studied, several present risks to the local aquatic environment.

Principais técnicas de preparo de amostra para a determinação de resíduos de agrotóxicos em água por cromatografia líquida com detecção por arranjo de diodos e por espectrometria de massas

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.

Metodologia para preservação do fungicida mancozebe em amostras de solo

The influence of temperature, storage time and the addition of hydrochloride L-cysteine in the preservation of the fungicide mancozeb was studied under field conditions in the surface layer of a Cambisol collected in an area planted with cabbage in Nova Friburgo - RJ, Brazil. The results of this study showed an efficiency of up to 42% in the preservation of the fungicide in the samples treated with cysteine and stored at low temperatures compared to those not treated and kept at room temperature

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%.