Determination of sugar cane herbicides in soil and soil treated with sugar cane vinasse by solid-phase extraction and HPLC-UV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Use of sugar cane bagasse as solid phase extractor for cadmium determination by FAAS

The present paper describes the use of sugar cane bagasse as solid phase extractor for cadmium determination after complexation of the analyte with ammonium diethyldithiophosphate (ADDP) and sorption of the Cd-DDP complexes on the solid support. The concomitants were separated using a flow injection analysis (FIA) system coupled to flame atomic absorption spectrometry (FAAS) for determination. The main parameters such as ADDP concentration, acid medium, flow rate, reaction coil length, and reaction time were investigated.The results obtained with HNO3 showed good accuracy and precision. The enhancement factor was 20.5 times for a 120-second preconcentration time, and the analytical frequency was 25 determinations per hour. The calibration curve was linear over the concentration range of 1-40 mu g L-1 Cd with a LOD of 0.697 mu g L-1 Cd and a relative standard deviation of 0.96% after 12 successive measurements of 30 mu g L-1 Cd.The proposed method was evaluated for the FIA-FAAS analysis of certified reference materials (tomato leaves, spinach leaves, and bovine liver) and Cd-spiked foods (shrimp, sardine, tuna, chicken liver and bovine liver). Good recoveries (80.0-97.1%) for the Cd-spiked samples and certified reference materials were obtained. The results of bagasse-packed minicolumns were compared with Si-C,8 packed minicolumns. The F-test was applied between Si-C-18/Bagasse minicolumns, Si-C-18/certified values, and bagasse/certified values. It was found that the results were in agreement with the certified values at a 95% confidence level.

Solid-phase extraction of sugar cane soot extract for analysis by gas chromatography with flame ionisation and mass spectrometric detection

The incomplete combustion of biomass is one of the most important sources of emissions of organic compounds into the atmosphere, like polycyclic aromatic hydrocarbons (PAHs) which show genotoxic activity. Since environmental samples generally contain interferents and trace amounts of PAHs of interest, concentration and clean-up procedures are usually required prior to the final chromatographic analysis. This paper discusses the performance of Sep-Pak cartridges (silica gel and RP18) on clean-up of sugar cane soot extract. The best results were obtained with a silica Sep-Pak cartridge. The recoveries ranged from 79% (benzo[b]fluoranthene) to 113% (benzo[e]pyrene). (C) 2000 Elsevier B.V. B.V. All rights reserved.

Characterisation of sugar cane combustion particles in the Araraquara region, Southeast Brazil

Biomass burning is an important primary and secondary source of aerosol particles. The presence of carbonaceous particles in the respirable size range makes the study of this fraction important in view of possible health and climatic effects. The annual burning of sugar cane plantations causes emission of huge amounts of pyrogenic particles. Aerosol samples were collected in Araraquara city, São Paulo state, Brazil, during the harvest season for fine and coarse particles and bulk; they were analysed by electron-probe microanalysis, including facilities for low-Z element determination (low-Z EPMA) and by energy-dispersive X-ray fluorescence (EDXRF), in order to investigate the elemental composition of individual particles and bulk samples, respectively. Numerical analysis of the EPMA results by hierarchical clustering shows high contributions of carbonaceous particles that can be distinguished mainly in two different types: biogenic and carbon-rich. Additionally, two significant contributions of aluminosilicate particles were identified: as rather pure aluminosilicates or mixed with carbonaceous species. The EDXRF results are compatible with those of aerosol particles in Amazon, which is nowadays one of the main sources of biogenic particles in the world.

Influence of sugar cane burning on aerosol soluble ion composition in Southeastern Brazil

Seasonal variability in the major soluble ion composition of atmospheric particulate matter in the principal sugar cane growing region of central São Paulo State indicates that pre-harvest burning of sugar cane plants is an important influence on the regional scale aerosol chemistry. Samples of particulate matter were collected between April 1999 and February 2001 in coarse (> 3.5 mum) and fine (< 3.5 mum) fractions, and analysed for HCOO-, CH3COO-, C2C42-, SO42- . Results indicated that the principal sources of the aerosols investigated NO3-, Cl-, Na+, K+, NH4+, Mg2+ and Ca2+ were local or regional in nature (scale of tens to a few hundreds of km), and that differences between air masses of varying origins were small. Fine particles were typically acidic, containing secondary nitrates, sulphates and organic species. Coarse fraction concentrations were mainly influenced by physical parameters (wind speed, movement of vehicles and surface condition) affecting rates of re-suspension, although secondary nitrate and sulphate were also present in the larger particles.Concentrations of all measured species except sodium and chloride were higher during the burning season. Although concentrations were lower than often found in polluted urban environments, the massive increases during much of the year, due to a single anthropogenic activity (sugar cane burning) are indicative of a very large perturbation of the lower troposphere in the region relative to the natural condition. These aerosols are suspected of promoting respiratory disease. They also represent an important mechanism for the tropospheric transport of species relevant to surface acidification (sulphates, nitrates, ammonium and organic acids) and soil nutrient status (potassium, nitrogen, ammonium, calcium), so their impact on fragile natural ecosystems (following deposition) needs to be considered. (C) 2004 Elsevier Ltd. All rights reserved.

Influence of sugar cane vinasse on the sorption and degradation of herbicides in soil under controlled conditions

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Chromosome analysis of two species of sugar cane pests of the genus Mahanarva (Homoptera, Cercopidae)

Studies on the cytogenetics of Homoptera are scarce. Some references in the literature have reported a chromosome number for the genus ranging from n=5 to 19 and 2n=10 to 2n=39 chromosomes. The genus Mahanarva includes two species of agricultural importance as pests of sugar cane culture in Brazil. We report here the first data concerning the chromosome number and morphology of the species Mahanarva fimbriolata and M. posticata. The chromosome number observed for the two species was 2n=19 for males and 2n=20 for females. The sex determining mechanism of these species was of the XX/X0 type (for males and females, respectively), with chromosome X being the smallest in the complement.

Windrowing and prismatic baling of sugar cane vegetal residues: Some operational parameters and energetic efficiency

It was evaluated the energetic efficiency and operational parameters of a windrowing and prismatic baling, both from CASE NEW HOLLAND® operations in sugarcane vegetal residues (green leaves, dry leaves and tops) picked mechanically in green cane. The area belongs to COSTA PINTO MILL (COSAN® Group) which was harvested mechanically by combines in the State of Sao Paulo, Brazil. The geographic location of the area is: Latitude 22°40'30S, Longitude 47°36'38W and Altitude of 605m. The variety was RB 82-5336, planted in 1.40m row spacing, with 78t.ha-1 yield. The vegetal residues analysis obtained 69.93% of leaves, 21.44% of stalks fractions, 2.27% of tops and 6.36% of total strange matter. The vegetal residues values were: gross heat of 18.43MJ.kg-1, low heat of 17.00MJ.kg'1 and useful heat of 12.94MJ.kg-1. The vegetal residues average energetic potential was 342.48GJ.ha-1. The treatments were simple, double and triple windrowing. The use of the rake and prismatic baler to pick up the residues was viable. The simple windrowing treatment presented the best results: effective capacity of 83.06t.ha-1, fuel consumption of 0.18L.t -1 and 99.95% of positive energetic efficiency. The bales obtained in the treatment of triple windrowing presented the largest specific mass average of 221.11kg.m-3. The soil amount in the bales increased with successive windrowing. The baling operation in the triple windrowing treatment obtained better results, presenting the effective capacities of 20.29t.h -1 and 1.45ha.h-1 and fuel consumption of for baled in 1.37L.t-1. The high total energetic efficiency of 99.53% indicates that is technically viable the withdrawal of the vegetal residues.

Windrowing and cylindrical baling of sugar cane vegetal residues: Some operational parameters and energetic efficiency

The objective of this study was to analyze the sugar cane vegetal residues collection, as well as determining its energetic potential, using a rake and cylindrical baler, both from NEW HOLLAND® under two different windrowing process (simple and double). The field tests were carried out in an area that belongs to COSTA PINTO MILL (COSAN® Group) in the city of Piracicaba, Sao Paulo State, Brazil. The geographic location of the area is: Latitude 22°4030'S, Longitude 47°3633'W and altitude of 605m. From the trash analysis, before the baling, the following average results were obtained: 69.93% of leaves; 2.27% of stalks fractions; 21.44% of tops and 6.36% of total strange matter. The estimated residues yield was 27.01 tons.ha -1 with a gross heat of 18.43 MJ.kg-1, low heat of 17.01 MJ.kg-1, useful heat of 13.32 MJ.kg-1, average moisture of 20.76% and an energetic potential of 494,875.09 MJ.ha-1. In the windrowing operations (simple and double) the averages of the 5 out of 13 analyzed variable presented differences between them in a 1% level of significance in the Tukey Test. The averages comparison of the results for bale's specific mass and the effective capacities (ton.h-1) e (ha.h-1) had been significant at a 5% level in the Tukey Test. The comparisons of the averages for the results had been significant to 1% level. The strange matter averages of the bales did not differed between them.

Lidar observation campaign of sugar cane fires and industrial emissions in the State of São Paulo, Brazil

Brazil has an important role in the biomass burning, with the detection of approximately 100,000 burning spots in a single year (2007). Most of these spots occur in the southern part of the Amazon basin during the dry season (from August to november) and these emissions reach the southeast of the country, a highly populated region and with serious urban air pollution problems. With the growing demand on biofuels, sugarcane is considerably expanding in the state of São Paulo, being a strong contributor to the bad air quality in this region. In the state of São Paulo, the main land use are pasture and sugarcane crop, that covers around 50% and 10% of the total area, respectively. Despite the aerosol from sugarcane burning having reduced atmospheric residence time, from a few days to some weeks, they might get together with those aerosol which spread over long distances (hundreds to thousands of kilometers). In the period of June through February 2010 a LIDAR observation campaign was carried in the state of São Paulo, Brazil, in order to observe and characterize optically the aerosols from two distinct sources, namely, sugar cane biomass burning and industrial emissions. For this purpose 2 LIDAR systems were available, one mobile and the other placed in a laboratory, both working in the visible (532 nm) and additionally the mobile system had a Raman channel available (607 nm). Also this campaign counted with a SODAR, a meteorological RADAR specially set up to detect aerosol echoes and gas-particle analyzers. To guarantee a good regional coverage 4 distinct sites were available to deploy the instruments, 2 in the near field of biomass burning activities (Rio Claro and Bauru), one for industrial emissions (Cubatão) and others from urban sources (São Paulo). The whole campaign provide the equivalent of 30 days of measurements which allowed us to get aerosol optical properties such as backscattering/extinction coefficients, scatter and LIDAR ratios, those were used to correlate with air quality and meteorological indicators and quantities. In this paper we should focus on the preliminary results of the Raman LIDAR system and its derived aerosol optical quantities. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Initial analysis from a Lidar observation campaign of sugar cane fires in the central and western portion of the S̃ao Paulo State - Brazil

The central and western portion of the S̃ao Paulo State has large areas of sugar cane plantations, and due to the growing demand for biofuels, the production is increasing every year. During the harvest period some plantation areas are burnt a few hours before the manual cutting, causing significant quantities of biomass burning aerosol to be injected into the atmosphere. During August 2010, a field campaign has been carried out in Ourinhos, situated in the south-western region of S̃ao Paulo State. A 2-channel Raman Lidar system and two meteorological S-Band Doppler Radars are used to indentify and quantify the biomass burning plumes. In addiction, CALIPSO Satellite observations were used to compare the aerosol optical properties detected in that region with those retrieved by Raman Lidar system. Although the campaign yielded 30 days of measurements, this paper will be focusing only one case study, when aerosols released from nearby sugar cane fires were detected by the Lidar system during a CALIPSO overpass. The meteorological radar, installed in Bauru, approximately 110 km northeast from the experimental site, had recorded echoes (dense smoke comprising aerosols) from several fires occurring close to the Raman Lidar system, which also detected an intense load of aerosol in the atmosphere. HYSPLIT model forward trajectories presented a strong indication that both instruments have measured the same air masss parcels, corroborated with the Lidar Ratio values from the 532 nm elastic and 607 nm Raman N2 channel analyses and data retrieved from CALIPSO have indicated the predominance of aerosol from biomass burning sources. © 2011 SPIE.

The enzymatic recalcitrance of internodes of sugar cane hybrids with contrasting lignin contents

The recalcitrance in grasses varies according to cell type and maturation. The origin of the recalcitrance in different regions from sugar cane internodes with varied lignin contents was evaluated. The efficiency of enzymatic hydrolysis was correlated with the chemical, micromorphological and microspectrophotometric characteristics of the samples. The internodes of three sugar cane hybrids were dissected into four different fractions. The outermost fraction and the rind were the most recalcitrant regions, whereas the pith-rind interface and the pith were less recalcitrant. Cellulose conversion reached 86% after 72h of enzymatic digestion of the pith from the hybrid with the lowest lignin content. There was an inversely proportional correlation between the area occupied by vascular bundles and the efficiency of cellulose hydrolysis. High cellulose and low lignin or hemicellulose contents enhanced the efficiency of enzymatic hydrolysis of the polysaccharides. The critical evaluation of the results permitted to propose an empirical parameter for predicting cellulose conversion levels that accounts for the positive effect of high cellulose and low lignin plus hemicellulose and the detrimental effect of abundant vascular bundles. The cellulose conversion levels fit well to this calculated parameter, following a second order polynomial with an r2 value of 0.96. © 2013 Elsevier B.V.