Due to the expansion of sugarcane crops and the high costs of agricultural inputs, an alternative for fertilization of the soil is the use of humic substances (HS) because they improve its physical-chemical properties. The objective of this study was to assess the biological degradation of fipronil in soil supplemented with HS. For determination of fipronil and its metabolites, we validated a quick, easy, cheap, effective, rugged, and safe gas chromatography-mass spectrometry (QuEChERS/GC-MS) method, which yielded detection and quantification limits of 15.0 and 62.5 ng g-1, respectively. The method presented linearity of 0.99, precision between 1.5 and 10.9%, while the recovery ranged from 78 to 98%, with precision (relative standard deviation (RSD)) < 5%. The strain B. thailandensis of Burkholderia sp. grew under typical conditions for degradation of fipronil. Eight treatments assessed the degradation by B. thailandensis in the presence of HS. The metabolites produced in the experiment, although detected, could not be quantified because they were below the limit of quantification of the method. Our results showed that B. thailandensis has the potential to degrade fipronil, and that HS is not toxic to the microbiota, and does not inactivate fipronil.

A method using dispersive liquid-liquid microextraction (DLLME) based on low density solvent (LDS) combined with liquid chromatography with diode array detection (LC-DAD) has been developed for determination of parabens. Some DLLME parameters such as kind and volumes of extraction and disperser solvents, pH of the aqueous samples, ionic strength, extraction, centrifugation and speed time, were investigated. The method exhibits good linearity (0.9990 to 0.9993), limits of detection (0.5-0.8 µg L-1), and limits of quantification (1.3-2.4 µg L-1). In optimum conditions, enrichment factors and recoveries of studied parabens obtained were 38.9 to 88.4% and 30.3 to 68.0%, respectively. Surface water samples collected from Mogi Guaçu River (São Paulo state, Brazil) were analyzed, showing average contents of methyl-, ethyl-, propyl-, and n-butylparaben of 8.0, 5.8, 13.1 and 15.1 µg L-1, respectively. This is the first study on parabens in a Brazilian River, in a long stretch of river (ca. 300 km of extension).

Diuron e Irgarol são anti-incrustantes que, a despeito das evidências de suas toxicidades para várias espécies marinhas, ainda são utilizados em pinturas de embarcações e estruturas marítimas. No caso do Irgarol, já existe restrição de uso em vários países. Neste estudo, que é o primeiro registro dos biocidas na região caracterizada como sendo uma das maiores extensões contínuas de manguezal em todo o mundo, a presença dos biocidas foi investigada durante dois anos, em um porto de intenso tráfego marítimo (Porto do Itaqui, nordeste do Brasil). Com intuito de selecionar o método analítico com sensibilidade e seletividade apropriadas, cromatografia líquida com detecção por conjunto de diodos (HPLC-DAD) e cromatografia líquida com detecção por espectrometria de massas em interface electrospray (LC-ESI-MS/MS) foram devidamente validados e comparados. Em ambos os métodos as amostras foram previamente concentradas em cartuchos de extração em fase sólida. LC-ESI-MS/MS foi o método selecionado em razão da melhor sensibilidade. Diuron e Irgarol foram identificados, respectivamente, em treze e dezenove das vinte e quatro amostras coletadas, em concentrações que variaram de 0,05 a 7,80 µg L-1 e de 0,01 a 4,80 µg L-1, respectivamente. Tais concentrações são ambientalmente relevantes e potencialmente prejudiciais aos organismos aquáticos do ambiente em estudo.

Diuron and Irgarol are antifouling booster that, despite evidences of their toxicities to various marine species, are still being used in paints of boats and marine structures. Irgarol has already been restricted in some countries though. In the present study, which is the first record of the antifouling biocides in this region characterized as one of the largest continuous mangrove area worldwide, the presence of both biocides was investigated during two years in surface water of a Port with intense maritime traffic (Itaqui Harbor, Northeastern Brazil). In order to select the analytical method with suitable sensitivity and selectivity, liquid chromatography with diode array detection (HPLC-DAD) and liquid chromatography with electrospray interface tandem mass spectrometry (LC-ESI-MS/MS) were properly validated and compared. For both methods, samples were previously concentrated into solid phase extraction cartridges. LC-ESI-MS/MS was the selected method due to better sensibility. Diuron and Irgarol were identified, respectively, on thirteen and nineteen of the twenty-four samples and concentrations ranged from 0.05 to 7.80 µg L-1 and from 0.01 to 4.80 µg L-1, respectively. Such concentrations are environmentally relevant and might cause potential harm to aquatic organisms of the studied environment.

Este artigo descreve os resultados da fotodegradação de três tipos de fluidos de corte solúveis e emulsionavéis em meio aquoso, usando TiO2 como catalisador em suspensão e radiação UV. O TiO2 mostrou ser um catalisador efetivo na degradação dos fluidos de corte investigados. A velocidade de degradação depende do pH e da natureza dos fluidos. O melhor desempenho do catalisador foi observado em pH = 8,0 para todos os fluidos, quando mais de 70% da carga orgânica foi decomposta.

This paper describes results of the photo-degradation of three types of soluble and emulsive cutting fluids in an aqueous medium, using TiO2 as catalyst in suspension and UV radiation. The TiO2 proved to be an effective catalyst for the degradation of the cutting fluids investigated. The degradation rate depends on pH and nature of the fluids. The best performance of catalyst was observed at pH 8.0 for all the fluids when most of 70% of the organic load was decomposed.

Um estudo sobre os impactos ambientais causados por atividades agrícolas e industriais, ao longo da bacia do rio Mogi Guaçu, foi realizado neste trabalho. A concentração de alguns metais (Fe, Cd, Cu, Cr, Zn, Ni, Pb e Mn) foi determinada em quinze estações de coleta de sedimentos e em dois períodos diferentes: chuvoso (Março/2001) e seco (Junho/2001). Os métodos de reconhecimento de padrões PCA e HCA foram utilizados para agrupar as amostras coletadas em São Paulo e em Minas Gerais e obter informações relevantes sobre as possíveis fontes de contaminação do rio Mogi Guaçu de acordo com o período de coleta das amostras. As análises quimiométricas realizadas, utilizando as amostras coletas em Março/2001 e em Junho/2001, indicaram que somente a concentração de Cd, Cu, Cr e Pb discrimina as amostras coletadas em São Paulo das amostras coletadas em Minas Gerais. A influência do período de coleta também foi analisada e os resultados obtidos indicaram que a concentração de quatro metais (Cd, Cr, Zn e Mn) foi importante para discriminar as amostras coletadas em Março/2001 das amostras coletadas em Junho/2001. De forma geral, a concentração dos metais estudados se apresenta em altos níveis em todas as estações de coleta e este fato caracteriza um ambiente com alto grau de contaminação causada, principalmente, por atividades antropogênicas.

A study on the environmental impacts caused by agricultural and industrial activities along the Mogi Guaçu river basin was carried out. Concentrations of some metals (Fe, Cd, Cu, Cr, Zn, Ni, Pb and Mn) were determined for fifteen collection stations in two different seasons: rainy (March/2001) and dry (June/2001). Pattern recognition methods (Principal Component Analysis and Hierarchical Cluster Analysis) were used to group samples collected in São Paulo and Minas Gerais and obtain relevant information on possible polluting sources of the Mogi Guaçu river according to the collection season of the samples. A chemometric analyses performed using samples collected in March/2001 and June/2001 indicated that only the concentrations of Cd, Cu, Cr and Pb discriminate samples collected in São Paulo from those collected in Minas Gerais. The influence of the collection season was also analysed and the results indicated that four metals (Cd, Cr, Zn and Mn) were important to discriminate samples collected in March/2001 (rainy season) from those collected in June/2001 (dry season). We verified that the concentrations of the metals studied are at high levels in all collection stations and this fact characterizes an environment with a high degree of contamination caused mainly by anthropogenic activities.

Os pesticidas têm sido usados para eliminar formas indesejáveis de vida nocivas à agricultura ou em áreas urbanas. O êxodo rural e, conseqüentemente, o aumento de preço da mão-de-obra remanescente nas áreas agrícolas levaram a um aumento do uso de herbicidas nas lavouras, principalmente do 2,4-D. Através de processos de adsorção-dessorção a mobilidade do herbicida 2,4-D pode ser avaliada. A contribuição da matéria orgânica do solo foi avaliada no processo de sorção do referido herbicida, constatando-se que a mesma contribui para o aumento de sua adsorção. A concentração ideal de 2,4-D a ser aplicada em um solo tipo latossolo roxo foi determinada através de experimentos de adsorção-dessorção.

Agrochemicals have been used to eliminate different undesirable forms of life both in agriculture and in urban areas. The rural exodus and the increase of labor costs in the agricultural areas have induced a greater use of herbicides in crops, mainly of 2,4-D. Through adsorption-desorption processes the mobility of this herbicide can be evaluated. The effect of organic matter on sorption of 2,4-D in soil has been studied. Organic matter contributed to the increase of 2,4-D adsorption. The ideal concentrations of 2,4-D in yellow-red Latosol soils were determined based on adsorption-desorption experiments.