Theoretical analysis of aqueous residues incineration with oxygen enriched flames

The use of oxygen to enrich the oxidizer can be an attractive alternate to increase incineration rates of a combustion chamber originally designed to operate with air. For a certain fuel now rate, if some incineration parameters are held constant (as combustion chamber temperature, turbulence level, and residence time), an increase of incineration rates becomes possible with injection of oxygen. This work presents a theoretical evaluation of combustion air enrichment in a combustion chamber designed to incinerate aqueous residues using methane as fuel and air as oxidizer. Detailed chemistry was employed to predict pollutants formation. The overall process was investigated using the PSR routine from the CHEMKIN library. (C) 1999 Elsevier B.V. Ltd.

Effect of a pilot washing system on dicofol levels in orange matrix

An efficient analytical method is described for the analysis of dicofol residues in pulp and orange peel. Samples are mixed with Celite and transferred to chromatographic columns prepacked with silica gel. Dicofol is eluted with ethyl acetate, and the extracts are analyzed by gas chromatography with electron capture detection. Mean recoveries for dicofol at levels of 0.5, 2.0, 5.0, and 10 mg/kg ranged from 87 to 95% with relative standard deviation values between 2.6 and 9.0%. To investigate the effect of a pilot washing system on dicofol residues in oranges, the analytical procedure was applied to samples submitted to different treatments with commercial formulations under field and laboratory conditions. The orange samples with and without washing were analyzed in duplicate, and the results indicated that washing under the described conditions did not allow a complete removal of dicofol residues from orange peel.

Sources of atmospheric acidity in an agricultural-industrial region of São Paulo State, Brazil

[1] Surface-based measurements of atmospheric formic acid (HCOOH), acetic acid (CH3COOH), sulfur dioxide (SO2), hydrogen chloride (HCl), and nitric acid (HNO3) were made in central São Paulo State, Brazil, between April 1999 and March 2000. Mean concentrations were 9.0 ppb (HCOOH), 1.3 ppb (CH3COOH), 4.9 ppb (SO2), 0.3 ppb (HCl), and 0.5 ppb (HNO3). Concentrations in sugar cane burning plumes were 1160-4230 ppb (HCOOH), 360-1750 ppb (CH3COOH), 10-630 ppb (SO2), 4-210 ppb (HCl), and 14-90 ppb (HNO3). Higher ambient concentrations of SO2, HCl and HNO3 were measured during the burning season (May-November). Concentrations of SO2 and HCl increased during the evening, and of HCOOH and CH3COOH were lowest in the morning, with peak levels in the afternoon. Ratios obtained between different species showed either nighttime maxima (SO2/HCOOH, SO2/CH3COOH, SO2/HNO3, CH3COOH/HNO3, SO2/HCl and HCOOH/HNO3), daytime maxima (HCOOH/HCl, CH3COOH/HCl and HNO3/HCl), or no clear trends (HCOOH/CH3COOH). Correlation analysis showed that SO2 and HCl were primary emissions from biomass burning and road transport; HCOOH, HNO3 and CH3COOH were products of photochemistry; HCOOH and CH3COOH were emitted directly during combustion as well as from biogenic sources. Biomass burning affected atmospheric acidity on a regional scale, while vehicular emissions had greater impact in urban and adjacent areas. Atmospheric ammonia levels were insufficient to neutralize atmospheric acidity, which was mainly removed by deposition to the surface.

Measurements of gunshot residues by sector field inductively coupled plasma mass spectrometry - Further studies with pistols

The most popular handgun in Brazil is the single round-barrel caliber 0.38 revolver. In recent years, however, owing to the modernization of police arms and their availability on the legal and illicit markets, pistols have become increasingly popular and currently represent about 20% of police seizures. In a previous paper we presented a novel collection method for gunshot residues (GSR) using a sampling procedure based on ethylenediamine-tetraacetic acid (EDTA) solution as a complexing agent on moistened swabs with subsequent detection using sector field-high resolution-inductively coupled plasma-mass spectrometry (SF-HR-ICP-MS). In the present paper, we discuss the capability of this methodology to identify antimony (Sb), barium (Ba) and lead (Pb) on the hands of volunteers after shot tests with 9 mm and 0.40 in. caliber pistols. Two types of munitions were tested: 9 mm Taurus and clean range. The use of a technique with high sensitivity, such as SF-HR-ICP-MS, permits the identification of low concentrations (less than 1 mu g/L) of metals in firearm residue and constitutes a powerful tool in forensic science. We also discuss the importance of the sampling procedure, including collection from a different body part than the gun hand of the suspect. Comparison of the analytical data obtained allows clear discrimination between samples from the hands of shooters and non-shooters. (C) 2007 Elsevier B.V.. All rights reserved.

Kinetic of thermal decomposition of residues from different kinds of composting

Non-isothermal kinetic parameters regarding to the thermal decomposition of the ligninocellulosic fraction present in compost from urban solid residues (USR) obtained through stack covered (SC) with composted material, comes from the usine in composing of Araraquara city, São Paulo state, Brazil, and from stack containing academic restaurant organic solid residues (SAR). The samples were periodically revolved round 132 days of composting.Results from TG, DTG and DSC curves obtained on inert atmosphere indicated that the lignocellulosic fraction present, despite the slow degradation during the composting process, is thermally less stable than other substances originated during that process. The lignocellulosic fraction decomposition, between 200 and 400degreesC, were kinetically evaluated through non-isothermal methods of analysis.By using the Flynn-Wall and Ozawa isoconversional method, the medium activation energy, E-a, and pre-exponential factor, IgA, were 283.0+/-4.6, 257.6+/-1.3 U mol(-1) and 25.4+/-0.8, 23.2+/-0.2 min(-1),to the SC and SAR, respectively, at 95% confidence level.From E-a, and IgA values and DSC curves, Malek procedure could be applied, Suggesting that the SB (Sestik-Berggren) kinetic model is suitable for the first thermal decomposition step.

A simplified method for the determination of fenpropathrin residues in fruits

A simple and efficient method is described for the determination of fenpropathrin in oranges, pears, apples and strawberries. The procedure: is based on the extraction of each homogenized fruit sample with hexane:acetone (1:1, v/v) mixture, followed, by a cleanup technique on a column packed with florisil, using a hexane:ethyl ether (7:3, v/v) mixture, and gas chromatographic, analysis with electron capture detection (ECD). The fortification levels (0.5; 1.0; 2.0 mg kg(-1)) were selected according to the maximum residue limits (MRLs) established for fenpropathrin by Brazilian legislation. Mean recoveries from five replicates of fortified fruit samples ranged from 83 % to 98 %, with:coefficients of variation from 1.4 to 13.5 and detection limits varying from 0.1 to 0.2 mg kg(-1).

Determination of fluquinconazole, pyrimethanil, and clofentezine residues in fruits by liquid chromatography with ultraviolet detection

A simple method was developed for the determination of fluquinconazole, pyrimethanil, and clofentezine in whole fruit; peel; and pulp of mango, apple, and papaya. These compounds were extracted from fruit samples with a mixture of ethyl acetate-n-hexane (1 + 1, v/v). An aliquot (2 mL) of the extract was evaporated to near dryness under a stream of nitrogen, and the residue was dissolved with 2 mL methanol. The analysis was performed by means of liquid chromatography with ultraviolet detection at 254 nm using a gradient solvent system. The method was validated with fortified fruit samples at concentration levels of 0.05, 0.10, 0.20, and 0.50 mg/kg. Average recoveries (4-8 replicates) ranged from 80 to 95% with relative standard deviations between 3.5 and 12.7%. Detection limits ranged from 0.03 to 0.05 mg/kg for fruit pulp and 0.03 mg/kg for whole fruit. The quantitation limits ranged from 0.05 to 0.10 mg/kg for fruit pulp and 0.05 mg/kg for whole fruit. The analytical method was applied to fruit samples obtained from local markets.

Pesticides in the distilled spirits of wine and its byproducts

The fate of eight fungicides (benalaxyl, fenarimol, iprodione, metalaxyl, myclobutanil, procymidone, triadimefon, and vinclozolin) and five insecticides (dimethoate, fenthion, methidathion, parathion methyl, and quinalphos) in wine and its byproducts (cake and lees) during the production of distilled spirits was studied. Among the pesticides studied, only fenthion, quinalphos, and vinclozolin residues were present in the distilled spirits. During wine distillation, respectively 13% and 5% of the initial residues of fenthion and vinclozolin were transferred to the distilled spirit. Low percentages (2% for fenthion and 0.1% for vinclozolin) of these active ingredients (AI) also passed from the lees to the final-distilled spirit, when samples were fortified at 10.1 and 26.1 ppm for fenthion and vinclozolin, respectively. Quinalphos passed only from the lees to the final-distilled spirit in percentages lower than 1% when samples were fortified at the highest concentration (4.6 ppm).

EVOLUTION PATTERNS OF THE SOIL ORGANIC-MATTER IN SOME AGRICULTURAL SYSTEMS IN THE BRAZILIAN CERRADO REGION

Several changes in the soil humus characteristics were observed after clearing the Central Brazil virgin forest. When compared with the original ''Cerrado'' forest, the soils from the agricultural systems showed increased values for cation exchange capacity, total organic matter and non-extractable humin. The humic acid fraction underwent some changes suggesting increased oxidation and decreased aliphatic content. The soil organic N tends to accumulate in the insoluble humus fractions.The above changes were much less intense when the virgin forest was transformed into pastures. Under these conditions, the most significant changes were the reduction of readily biodegradable soil organic matter fractions.In view of the intensity of the lixiviation processes in the area studied, the above changes may be connected with the reduction in aggregate stability observed in the cleared sites.In general, the characteristics of the humus formations in the ''Cerrado'' region suggested high resistance to external factors, which is in part attributed to the active insolubilization of humic colloids by the Al and Fe oxides. In the absence of erosive processes in the cleared sites, additional humus stability may conform both to selective biodegradation and/or lixiviation of the humic colloids, or to the effects of the fire used in soil management.

Determination of carbamate residues in crop samples by cholinesterase-based biosensors and chromatographic techniques

An amperometric biosensor based on cholinesterase (ChE) has been used for the determination of selected carbamate insecticides in vegetable samples. The linear range of the biosensor for the N-methylcarbamates (aldicarb, carbaryl, carbofuran, methomyl and propoxur) varied from 5 x 10(-5) to 50 mg kg(-1). Limits of detection were calculated on the basis that the ChE enzymes were 10% inhibited and varied, depending of the combination ChE (as acetyl- or butyrylcholinesterase) vs. inhibitor (pesticide), from 1 x 10(-4) to 3.5 mg kg(-1). The biosensor-based carbamate determination was compared to liquid chromatography/UV methods. Three vegetable samples were spiked with carbofuran and propoxur at 125 mu g kg(-1) followed by conventional procedures. Good correlations were observed for carbofuran in the vegetable extracts (79, 96 and 91% recoveries for potato, carrot and sweet pepper, respectively), whereas for propoxur unsatisfactory results were obtained. Potato and carrot samples were spiked with 10, 50 and 125 mu g kg(-1) carbofuran, followed by direct determination by the amperometric biosensor. The fortified sampler; resulted in very high inhibition values, and recoveries were: 28, 34 and 99% for potato, and 140, 90 and 101% for carrot, respectively, at these three fortification levels. (C) 1998 Elsevier B.V. B.V.

NO2 emissions from agricultural burning in São Paulo, Brazil

We report here on the application of a compact ultraviolet spectrometer to measurement of NO2 emissions from sugar cane field burns in São Paulo, Brazil, the time-resolved NO2 emission from a 10 ha plot peaked at about 240 g (NO2) s(-1), and amounted to a total yield of approximately 50 kg of N, or about 0.5 g (N) m(-2). Emission of N as NOx (i.e., NO + NO2) was estimated at 2.5 g (N) in 2, equivalent to 30% of applied fertilizer nitrogen. The corresponding annual emission of NOx nitrogen from São Paulo State sugar cane burning was >45 Gg N. In contrast to mechanized harvesting, which does not require prior burning of the crop, manual harvesting with burning acts to recycle nitrogen into surface soils and ecosystems.

Thermostable invertases from Paecylomyces variotii produced under submerged and solid-state fermentation using agroindustrial residues

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Greenhouse gas balance due to the conversion of sugarcane areas from burned to green harvest in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determination of organochlorine pesticides and polychlorinated biphenyls residues in municipal solid waste compost by gas chromatography with electron-capture detection

A simple and efficient method for the simultaneous gas chromatographic determination of ten organochlorine pesticides (alpha-HCH, beta-HCH, gamma-HCH, p,p'-DDT, o,p'-DDT, p,p'-DDD, p,p'-DDE, aldrin, endrin, and dieldrin) and six congeners of PCBs (PCB 28, 52, 118, 138, 153, and 180) in municipal solid waste compost is described. The procedure involves a solid-phase dispersion matrix using celite as dispersant sorbent, alumina as clean up sorbent and hexane-dichloromethane (7:3, v/v) mixture as eluting solvent. An additional purification step with copper was necessary to eliminate sulphur. Analysis of the sample was performed by GC-ECD. The method was validated with fortified samples at two concentration levels (0.025 and 0.05 mg kg(-1)). Average recovery ranged from 77 to 121% with relative standard deviation between 1 and 18%. The detection limits, which ranged from 0.003 to 0.01 mg kg-1, were lower than those established by the Baden-Wurttemberg directive (0.033 mg kg(-1)).