Contaminação ambiental por compostos organoestânicos

The occurrence and the effects of organotin compounds (OTs) have been studied since a long time, due to their widespread use and deleterious effects. Some OTs are used as pesticides in crops, or as biocides in antifouling paints, applied in the ship hulls to avoid attachment and growth of tube worms, mussels and barnacles. However, "nontarget" organisms may be exposed, resulting in the poisoning of biological system, originating mutations and sentencing species to extinction. In this work we reported a revision study on the history of OTs and the techniques developed for its assessment and control.

Contaminação de águas por BTXs e processos utilizados na remediação de sítios contaminados

After decades of polluting actions the environment manifests serious and global consequences. The contamination of soils and groundwater by organic compounds is a widespread problem mainly on account of contamination by leakage from underground storage tanks, which often results in the release of gasoline or other chemicals. The main problem about groundwater contamination is due to the toxicity of water-soluble components such as benzene, toluene and xylene (BTX). In the present work a study about classical and modern methods for remediation of BTX is reported.

Análise de praguicidas organofosforados em água por extração em fase sólida (SPE) utilizando discos C18 e cromatografia em fase gasosa: avaliação da contaminação do reservatório de Furnas (MG-Brasil)

Solid phase extraction (SPE) in C18 disks has been optimized and validated for extraction of 5 organophosphorus (OP) pesticides in water. Extraction has been followed by separation and detection by gas chromatography/flame photometry. Excellent linearity was obtained for all compounds (r greater than 0.99), with CVs between 1.0-6.9%, recoveries between 73-95% and quantification limits between 2.5-5.0 µg L-1. Samples from Furnas dam were analyzed monthly during one year and 10% showed OP pesticide residues.

Adsorção de As, Cu, Pb e Cr na avaliação da capacidade de fixação de metais por resíduo de mineradoras de ferro

Two samples of residues from iron mining plants have been investigated for their retention capacity of As, Cu, Cr, and Pb. The sample with the higher content of iron oxides showed the highest capacity to retain metals. The adsorption affinity series changes from Pb>Cu>Cr~As to As>Pb>Cu>Cr or As>Cu>Cr>Pb, depending on the material and the concentration of the initial solution. In the competitive environment, the Pb adsorption decreases and the As, Cu and Cr adsorption increases. Sequential extraction procedures, carried out after adsorption batch experiments, showed that the most important adsorption process occurs in the oxide fraction and that the major part of the absorbed metal is remobilized from exchangeable and oxide fractions.

Preparação de amostra de fígado bovino e estudo de micro homogeneidade para a determinação de Cd E Pb por espectrometria de absorção atômica com atomização eletrotérmica e amostragem direta de sólido

This work describes a systematic study for bovine liver sample preparation for Cd and Pb determination by solid sampling electrothermal atomic absorption spectrometry. Samples were prepared using different procedures: (1) drying in a household microwave oven followed by drying in a stove at 60 ºC until constant mass, and (2) freeze-drying. Ball and cryogenic mills were used for grinding. Particle size, sample size and micro sample homogeneity were investigated. All prepared samples showed good homogeneity (He < 10) even for low sample mass, but samples dried in a microwave oven/stove and ground in a ball mill presented the best homogeneity.

Método multirresíduo para monitoramento de contaminação ambiental de pesticidas na região de Bauru (SP) usando mel como bio-indicador

The presence of residues of the major groups of pesticides (organohalogen, organophosphorous, pyrethroids and organonitrogen) in representative samples of honey produced in Bauru (state of São Paulo, Brazil) was investigated from 1999 through2004. A multiresidue method was applied to honey samples to determine 48 pesticides with recoveries ranging from 76 to 95%. The limits of detection found were lower than 10 µg/kg for GC-MS-SIM. The results indicated that most pesticides found in the samples belonged to the organohalogen and organonitrogen groups. Residues of malathion were detected in almost all of the samples in high concentration.

Avaliação de contaminação ambiental causada por poluentes orgânicos persistentes utilizando simulação computacional

Environmental concern is growing in the current days and there is global agreement to banish production and use of persistent organic pollutants (POP). The synthetic insecticides chlordecone and mirex, classified as POPs, have similar structures and they are potentially toxic. This work uses properties and physicochemical constants related to the pesticides and computational simulation to evaluate the leach phenomenon and persistency in soil. The largest tendency of persistence of the compound is found to be in the surface of soil, but even low concentration in water represents a high risk due to bioaccumulation in adipose tissue.

Contaminação de águas subterrâneas por pesticidas: avaliação preliminar

A discussion about groundwater contamination is presented in this work. Contamination by agricultural activity, more specifically by pesticides is emphasized. Indirect and direct estimates could be used to predict pesticide behavior in soil, and consequently, to evaluate the potential of groundwater contamination. These results could be applied to advise about the possibility of groundwater contamination by pesticides, and to provide subsidies for making decisions more quickly and efficiently.

Contaminação de aqüífero por hidrocarbonetos: estudo de caso na Vila Tupi, Porto Velho - Rondônia

Underground storage tanks (UST) are widely used in the Porto Velho area. A large number of these USTs are in bad condition due to corrosion processes causing groundwater contamination. A large number of these leaking underground fuel tanks (LUFT) are in urban areas but due to the lack of water quality monitoring, they are only detected when there is a high contamination level. This study identified petroleum hydrocarbons, derived from a LUFT, by a silica gel/petroleum ether partitioning gravimetric method and by gas chromatographic analysis of samples collected in wells dug in a gas station and in houses in the aforementioned neighborhood.

Determinação simultânea de As, Cd e Pb em amostras de água purificada para hemodiálise por espectrometria de absorção atômica com forno de grafite, após otimização multivariada baseada no uso de planejamento experimental

This paper reports the development of a methodology for simultaneously determining As, Cd and Pb, employing GF AAS with polarized Zeeman-effect background correction. In order to make the procedure applicable, the influence of pyrolysis and atomization temperatures and the amount of chemical modifiers were studied. Factorial and central composite designs were used to optimize these variables. Precision and accuracy of the method were investigated using Natural Water Reference material, Nist SRM 1640. Results are in agreement with certified values at the 95% confidence limit when the Student t-test is used. This methodology was used for quality control of purified water for hemodialysis.

Marcadores orgânicos de contaminação por esgotos sanitários em sedimentos superficiais da baía de Santos, São Paulo

Organic markers, such as sterols and ketones, were used to assess sewage contamination in sediments from the Santos Bay, SP, and its continental shelf. These compounds were analyzed by GC/FID after soxhlet extraction, clean up and derivatization. The concentration of coprostanol and ratios between selected sterols were used to evaluate fecal contamination. The stations located in the mid-western part of the Santos Bay presented organic matter from sewage due to the input of fecal material from the city of Santos by submarine sewage outfall. Stations located at the continental shelf did not present fecal contamination. Coprostanol levels in sewage outfall stations were higher in comparison to other Brazilian coastal areas, except Guanabara Bay/RJ, and could be related to the fraction of the population without sewage treatment.

Determination of Cd and Pb in fuel ethanol by filter furnace electrothermal atomic absorption spectrometry

A method was developed for quantification of Cd and Pb in ethanol fuel by filter furnace atomic absorption spectrometry. Filter furnace was used to eliminate the need for chemical modification, to stabilize volatile analytes and to allow the application of short pyrolysis step. The determinations in samples were carried out against calibration solutions prepared in ethanol. Recovery tests were made in seven commercial ethanol fuel samples with values between 90 and 120%. Limits of detection were 0.1 µg L-1 for Cd and 0.3 µg L-1 for Pb. Certified water samples (APS 1071, APS 1033, NIST 1643d, NIST 1640) were also used to evaluate accuracy and recoveries from 86.8% to115% were obtained.

Avaliação da contaminação por organofosforados em águas superficiais no município de Rondinha - Rio Grande do Sul

Water pollution is a serious environmental problem. In Rondinha, Rio Grande do Sul, on a small area planted with tobacco, it has been using organophosphates pesticides. The purpose of this study was to evaluate the organophosphates pesticides contamination of the superficial water in this municipality. The samples collected in fifteen places were evaluated by the method of organophosphates acethylcolinestherase inhibition. In five samples the organophosphates levels were above the limit established by CONAMA, indicating the necessity of arrangements that allow reducing the risk of the population and the environment contamination.

Analytical procedures for determining Pb and Sr isotopic compositions in water samples by ID-TIMS

Few articles deal with lead and strontium isotopic analysis of water samples. The aim of this study was to define the chemical procedures for Pb and Sr isotopic analyses of groundwater samples from an urban sedimentary aquifer. Thirty lead and fourteen strontium isotopic analyses were performed to test different analytical procedures. Pb and Sr isotopic ratios as well as Sr concentration did not vary using different chemical procedures. However, the Pb concentrations were very dependent on the different procedures. Therefore, the choice of the best analytical procedure was based on the Pb results, which indicated a higher reproducibility from samples that had been filtered and acidified before the evaporation, had their residues totally dissolved, and were purified by ion chromatography using the Biorad® column. Our results showed no changes in Pb ratios with the storage time.

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.