Insights into the dynamics and sources of atmospheric lead and particulate matter in Sao Paulo, Brazil, from high temporal resolution sampling

We present the first results of a study investigating the processes that control concentrations and sources of Pb and particulate matter in the atmosphere of Sao Paulo City Brazil Aerosols were collected with high temporal resolution (3 hours) during a four-day period in July 2005 The highest Pb concentrations measured coincided with large fireworks during celebration events and associated to high traffic occurrence Our high-resolution data highlights the impact that a singular transient event can have on air quality even in a megacity Under meteorological conditions non-conducive to pollutant dispersion Pb and particulate matter concentrations accumulated during the night leading to the highest concentrations in aerosols collected early in the morning of the following day The stable isotopes of Pb suggest that emissions from traffic remain an Important source of Pb in Sao Paulo City due to the large traffic fleet despite low Pb concentrations in fuels (C) 2010 Elsevier BV All rights reserved

Sampling, WLS, and Mixed Models

Mixed models may be defined with or without reference to sampling, and can be used to predict realized random effects, as when estimating the latent values of study subjects measured with response error. When the model is specified without reference to sampling, a simple mixed model includes two random variables, one stemming from an exchangeable distribution of latent values of study subjects and the other, from the study subjects` response error distributions. Positive probabilities are assigned to both potentially realizable responses and artificial responses that are not potentially realizable, resulting in artificial latent values. In contrast, finite population mixed models represent the two-stage process of sampling subjects and measuring their responses, where positive probabilities are only assigned to potentially realizable responses. A comparison of the estimators over the same potentially realizable responses indicates that the optimal linear mixed model estimator (the usual best linear unbiased predictor, BLUP) is often (but not always) more accurate than the comparable finite population mixed model estimator (the FPMM BLUP). We examine a simple example and provide the basis for a broader discussion of the role of conditioning, sampling, and model assumptions in developing inference.

Versatile microanalytical system with porous polypropylene capillary membrane for calibration gas generation and trace gaseous pollutants sampling applied to the analysis of formaldehyde, formic acid, acetic acid and ammonia in outdoor air

The analytical determination of atmospheric pollutants still presents challenges due to the low-level concentrations (frequently in the mu g m(-3) range) and their variations with sampling site and time In this work a capillary membrane diffusion scrubber (CMDS) was scaled down to match with capillary electrophoresis (CE) a quick separation technique that requires nothing more than some nanoliters of sample and when combined with capacitively coupled contactless conductometric detection (C(4)D) is particularly favorable for ionic species that do not absorb in the UV-vis region like the target analytes formaldehyde formic acid acetic acid and ammonium The CMDS was coaxially assembled inside a PTFE tube and fed with acceptor phase (deionized water for species with a high Henry s constant such as formaldehyde and carboxylic acids or acidic solution for ammonia sampling with equilibrium displacement to the non-volatile ammonium ion) at a low flow rate (8 3 nLs(-1)) while the sample was aspirated through the annular gap of the concentric tubes at 25 mLs(-1) A second unit in all similar to the CMDS was operated as a capillary membrane diffusion emitter (CMDE) generating a gas flow with know concentrations of ammonia for the evaluation of the CMDS The fluids of the system were driven with inexpensive aquarium air pumps and the collected samples were stored in vials cooled by a Peltier element Complete protocols were developed for the analysis in air of NH(3) CH(3)COOH HCOOH and with a derivatization setup CH(2)O by associating the CMDS collection with the determination by CE-C(4)D The ammonia concentrations obtained by electrophoresis were checked against the reference spectrophotometric method based on Berthelot s reaction Sensitivity enhancements of this reference method were achieved by using a modified Berthelot reaction solenoid micro-pumps for liquid propulsion and a long optical path cell based on a liquid core waveguide (LCW) All techniques and methods of this work are in line with the green analytical chemistry trends (C) 2010 Elsevier B V All rights reserved

Simultaneous determination of chromium and manganese in alumina by slurry sampling graphite furnace atomic absorption spectrometry using NbC and NaF as modifiers

This paper reports a method for the direct and simultaneous determination of Cr and Mn in alumina by slurry sampling graphite furnace atomic absorption spectrometry (SiS-SIMAAS) using niobium carbide (NbC) as a graphite platform modifier and sodium fluoride (NaF) as a matrix modifier. 350 mu g of Nb were thermally deposited on the platform surface allowing the formation of NbC (mp 3500 degrees C) to minimize the reaction between aluminium and carbon of the pyrolytic platform, improving the graphite tube lifetime up to 150 heating cycles. A solution of 0.2 mol L(-1) NaF was used as matrix modifier for alumina dissolution as cryolite-based melt, allowing volatilization during pyrolysis step. Masses (c.a. 50 mg) of sample were suspended in 30 ml of 2.0% (v/v) of HNO(3). Slurry was manually homogenized before sampling. Aliquots of 20 mu l of analytical solutions and slurry samples were co-injected into the graphite tube with 20 mu l of the matrix modifier. In the best conditions of the heating program, pyrolysis and atomization temperatures were 1300 degrees C and 2400 degrees C, respectively. A step of 1000 degrees C was optimized allowing the alumina dissolution to form cryolite. The accuracy of the proposed method has been evaluated by the analysis of standard reference materials. The found concentrations presented no statistical differences compared to the certified values at 95% of the confidence level. Limits of detection were 66 ng g(-1) for Cr and 102 ng g(-1) for Mn and the characteristic masses were 10 and 13 pg for Cr and Mn, respectively.

Feasibility of using in situ fusion for the determination of Co, Cr and Mn in Portland cement by direct solid sampling graphite furnace atomic absorption spectrometry

In situ fusion on the boat-type graphite platform has been used as a sample pretreatment for the direct determination of Co, Cr and Mn in Portland cement by solid sampling graphite furnace atomic absorption spectrometry (SS-GF AAS). The 3-field Zeeman technique was adopted for background correction to decrease the sensitivity during measurements. This strategy allowed working with up to 200 mu g of sample. The in situ fusion was accomplished using 10 mu L of a flux mixture 4.0% m/v Na(2)CO(3) + 4.0% m/v ZnO + 0.1% m/v Triton (R) X-100 added over the cement sample and heated at 800 degrees C for 20 s. The resulting mould was completely dissolved with 10 mu L of 0.1% m/v HNO(3). Limits of detection were 0.11 mu g g(-1) for Co, 1.1 mu g g(-1) for Cr and 1.9 mu g g(-1) for Mn. The accuracy of the proposed method has been evaluated by the analysis of certified reference materials. The values found presented no statistically significant differences compared to the certified values (Student`s t-test, p<0.05). In general, the relative standard deviation was lower than 12% (n = 5). (C) 2009 Elsevier B.V. All rights reserved.

Environmental formaldehyde analysis by active diffusive sampling with a bundle of polypropylene porous capillaries followed by capillary zone electrophoretic separation and contactless conductivity detection

Compared to other volatile carbonylic compounds present in outdoor air, formaldehyde (CH2O) is the most toxic, deserving more attention in terms of indoor and outdoor air quality legislation and control. The analytical determination of CH2O in air still presents challenges due to the low-level concentration (in the sub-ppb range) and its variation with sampling site and time. Of the many available analytical methods for carbonylic compounds, the most widespread one is the time consuming collection in cartridges impregnated with 2,4-dinitrophenylhydrazine followed by the analysis of the formed hydrazones by HPLC. The present work proposes the use of polypropylene hollow porous capillary fibers to achieve efficient CH2O collection. The Oxyphan (R) fiber (designed for blood oxygenation) was chosen for this purpose because it presents good mechanical resistance, high density of very fine pores and high ratio of collection area to volume of the acceptor fluid in the tube, all favorable for the development of air sampling apparatus. The collector device consists of a Teflon pipe inside of which a bundle of polypropylene microporous capillary membranes was introduced. While the acceptor passes at a low flow rate through the capillaries, the sampled air circulates around the fibers, impelled by a low flow membrane pump (of the type used for aquariums ventilation). The coupling of this sampling technique with the selective and quantitative determination of CH2O, in the form of hydroxymethanesulfonate (HMS) after derivatization with HSO3-, by capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-(CD)-D-4) enabled the development of a complete analytical protocol for the CH2O evaluation in air. (C) 2008 Published by Elsevier B.V.

Direct determination of iron in sand using solid sampling graphite furnace atomic absorption spectrometry

A fast and reliable method for the direct determination of iron in sand by solid sampling graphite furnace atomic absorption spectrometry was developed. A Zeeman-effect 3-field background corrector was used to decrease the sensitivity of spectrometer measurements. This strategy allowed working with up to 200 mu g of samples, thus improving the representativity. Using samples with small particle sizes (1-50 mu m) and adding 5 mu g Pd as chemical modifier, it was possible to obtain suitable calibration curves with aqueous reference solutions. The pyrolysis and atomization temperatures for the optimized heating program were 1400 and 2500 degrees C, respectively. The characteristic mass, based on integrated absorbance, was 56 pg, and the detection limits, calculated considering the variability of 20 consecutive measurements of platform inserted without sample was 32 pg. The accuracy of the procedure was checked with the analysis of two reference materials (IPT 62 and 63). The determined concentrations were in agreement with the recommended values (95% confidence level). Five sand samples were analyzed, and a good agreement (95% confidence level) was observed using the proposed method and conventional flame atomic absorption spectrometry. The relative standard deviations were lower than 25% (n = 5). The tube and boat platform lifetimes were around 1000 and 250 heating cycles, respectively.

Application of solid sampling device for direct determination of chromium and nickel in lubricating oils by graphite furnace atomic absorption spectrometry

One method using a solid sampling device for the direct determination of Cr and Ni in fresh and used lubricating oils by graphite furnace atomic absorption spectrometry are proposed. The high organic content in the samples was minimized using a digestion step at 400 degrees C in combination with an oxidant mixture 1.0% (v v(-1)) HNO3+15% (v v(-1)) H2O2+0.1% (m v(-1)) Triton X-100 for the in situ digestion. The 3-field mode Zeeman-effect allowed the spectrometer calibration up to 5 ng of Cr and Ni. The quantification limits were 0.86 mu g g(-1) for Cr and 0.82 mg g(-1) for Ni, respectively. The analysis of reference materials showed no statistically significant difference between the recommended values and those obtained by the proposed methods.

Isolation and characterization of Flavobacterium columnare (Bernardet et al. 2002) from four tropical fish species in Brazil

Flavobacterium columnare is the causative agent of columnaris disease in freshwater fish, implicated in skin and gill disease, often causing high mortality. The aim of this study was the isolation and characterization of Flavobacterium columnare in tropical fish in Brazil. Piracanjuba (Brycon orbignyanus), pacu (Piaractus mesopotamicus), tambaqui (Colossoma macropomum) and cascudo (Hypostomus plecostomus) were examined for external lesions showing signs of colunmaris disease such as greyish white spots, especially on the head, dorsal part and caudal fin of the fish. The sampling comprised 50 samples representing four different fish species selected for study. Samples for culture were obtained by skin and kidney scrapes with a sterile cotton swabs of columnaris disease fish and streaked onto Carlson and Pacha (1968) artificial culture medium (broth and solid) which were used for isolation. The strains in the liquid medium were Gram negative, long, filamentous, exhibited flexing movements (gliding motility), contained a large number of long slender bacteria and gathered into ‘columns'. Strains on the agar produced yellow-pale colonies, rather small, flat that had rhizoid edges. A total of four Flavobacterium columnare were isolated: 01 Brycon orbignyanus strain, 01 Piaractus mesopotamicus strain, 01 Colossoma macropomum strain, and 01 Hypostomus plecostomus strain. Biochemical characterization, with its absorption of Congo red dye, production of flexirubin-type pigments, H2S production and reduction of nitrates proved that the isolate could be classified as Flavobacterium columnare.

Spatial pattern detection modeling of thrips (Thrips tabaci) on onion fields

Onion (Allium cepa) is one of the most cultivated and consumed vegetables in Brazil and its importance is due to the large laborforce involved. One of the main pests that affect this crop is the Onion Thrips (Thrips tabaci), but the spatial distribution of this insect, although important, has not been considered in crop management recommendations, experimental planning or sampling procedures. Our purpose here is to consider statistical tools to detect and model spatial patterns of the occurrence of the onion thrips. In order to characterize the spatial distribution pattern of the Onion Thrips a survey was carried out to record the number of insects in each development phase on onion plant leaves, on different dates and sample locations, in four rural properties with neighboring farms under different infestation levels and planting methods. The Mantel randomization test proved to be a useful tool to test for spatial correlation which, when detected, was described by a mixed spatial Poisson model with a geostatistical random component and parameters allowing for a characterization of the spatial pattern, as well as the production of prediction maps of susceptibility to levels of infestation throughout the area.

The role of pH on the survival of rumen protozoa in steers

In order to study the effect of pH on defaunation in the rumen, four rumen fistulated steers were fed a basal roughage diet for a 4-week adaptation period followed by 17 weeks of feeding with three diets and two feeding levels of high concentrate diet. Rumen outflow fluid rate was evaluated in both ration levels. Rumen protozoa population was monitored weekly and when animals became defaunated, protozoa were reinoculated with rumen contents from one of the faunated steers. At every two weeks, during all the experimental period, rumen pH was measured in all animals at 0, 4, 8 and 12 h after feeding. It was observed an individual animal influence on the establishment and maintenance of the rumen ciliate protozoa population. In all sampling times, mean rumen pH values were higher in faunated steers than in the defaunated ones. No differences were observed in rumen outflow fluid rates between the two ration levels. Extended periods of low rumen pH are probably more detrimental to the survival of ciliate protozoa in the rumen than other factors.

Modelagem dos processos de remoção sulfato e dióxido de enxofre presente no particulado em diferentes localidades da região metropolitana de São Paulo

This article deals with the scavenging processes modeling of the particulate sulfate and the gas sulfur dioxide, emphasizing the synoptic conditions at different sampling sites in order to verify the domination of the in-cloud or below-cloud scavenging processes in the Metropolitan Area of São Paulo (RMSP). Three sampling sites were chosen: GV (Granja Viana) at RMSP surroundings, IAG-USP and Mackenzie (RMSP center). Basing on synoptic conditions, it was chosen a group of events where the numerical modeling, a simple scavenging model, was used. These synoptic conditions were usually convective cloud storms, which are usual at RMSP. The results show that the in-cloud processes were dominant (80%) for sulfate/sulfur dioxide scavenging processes, with below-cloud process indicating around 20% of the total. Clearly convective events, with total rainfall higher than 20 mm, are better modeled than the stratiform events, with correlation coefficient of 0.92. There is also a clear association with events presenting higher rainfall amount and the ratio between modeled and observed data set with correlation coefficient of 0.63. Additionally, the suburb sampling site, GV, as expected due to the pollution source distance, presents in general smaller amount of rainwater sulfate (modeled and observed) than the center sampling site, Mackenzie, where the characterization event explains partially the rainfall concentration differences.

Diversidade de abelhas (Hymenoptera, Apidae) ao longo de um gradiente latitudinal na Mata Atlântica

A Mata Atlântica é um dos ambientes mais ricos e ameaçados do mundo, o que deveria ter estimulado em muito o estudo e a conservação do Bioma, mas a fauna de Hymenoptera permanece ainda relativamente pouco conhecida. Em especial, a fauna de abelhas da floresta ombrófila densa é pouco estudada em comparação à fauna das áreas abertas brasileiras. O projeto temático "Biodiversidade de Hymenoptera e Isoptera: riqueza e diversidade ao longo de um gradiente latitudinal na Mata Atlântica - a floresta úmida do leste do Brasil", integrante do Programa Biota-Fapesp, foi idealizado com o objetivo de catalogar térmitas, formigas e famílias selecionadas de vespas ao longo da Mata Atlântica, disponibilizando dados que permitam melhor embasar a conservação deste bioma. O protocolo de amostragem aplicada para a coleta de himenópteros (excluindo as formigas) empregou armadilhas Malaise, pratos-armadilha de cor amarela e esforço similar na varredura de vegetação ao longo de 17 localidades selecionadas, representando um gradiente de quase 20° de latitude na Mata Atlântica, dos Estados da Paraíba até Santa Catarina. Este protocolo foi definido para otimizar a coleta de vespas, sendo as abelhas um produto secundário da amostragem (levantamentos de abelhas em geral utilizam captura em flores ao longo das estações do ano). No entanto, devido à escala regional do projeto e ao grande esforço de amostragem, uma expressiva quantidade de abelhas foi coletada durante o projeto, incluindo novos registros de abelhas para a Mata Atlântica. Foi amostrado um total de 797 espécimes distribuídos em 105 espécies de abelhas; o grupo de abelhas mais rico e abundante foi Meliponina. Uma análise de correspondência "destendenciada" ('detrended correspondence analysis') aplicada à uma matriz de presença ou ausência de Meliponina revela a relativamente fraca influência do gradiente latitudinal na composição das assembléias de abelhas de Mata Atlântica. Uma listagem das espécies amostradas por localidade, com suas freqüências relativas, é apresentada e discutida.

Répteis da Estação Ecológica Serra Geral do Tocantins, Brasil Central

Os Cerrados sul-americanos abrigam alta diversidade de répteis, incluindo elevado número de endemismos. No entanto, o conhecimento desta diversidade é ainda incompleto frente à acelerada transformação das paisagens naturais no Brasil central. Constituem, portanto, uma das regiões prioritárias para estudo e conservação da biodiversidade mundial. Estudos intensivos sobre a fauna de répteis do Cerrado são necessários e urgentes para melhor compreensão dos processos que levaram à sua origem e distribuição e para subsidiar ações de conservação. Por meio de métodos padronizados, amostramos duas regiões ainda inexploradas da Estação Ecológica Serra Geral do Tocantins, situada na região do Jalapão. Registramos 45 espécies de répteis para a EESGT e entorno, o que representa uma riqueza alta e comparável à de outras regiões bem amostradas do Cerrado. Curvas de acumulação e estimadores indicam que a riqueza local de lagartos e anfisbenídeos aproxima-se da riqueza real enquanto a de serpentes é subestimada. A distribuição não-aleatória das espécies na paisagem concorda com evidências anteriores sugerindo utilização diferencial dos hábitats pelos répteis. Reunindo os resultados do presente estudo com os de levantamentos prévios realizados na região, registramos 88 espécies de répteis para o Jalapão sendo oito registros novos que incluem Bachia oxyrhina uma espécie recém descrita da região. As espécies da área apresentam três padrões gerais de distribuição: (1) espécies endêmicas do Cerrado, (2) espécies compartilhadas com domínios da diagonal de formações abertas sul-americanas, e (3) espécies de ampla ocorrência, compartilhadas também com ecossistemas florestais. Prevalecem espécies de ampla distribuição, porém é grande o número de espécies típicas do Cerrado, incluindo cinco possivelmente endêmicas do Jalapão, e há contribuição importante da fauna da Caatinga. A distribuição dos répteis em escala local e regional demonstra a necessidade de considerar a heterogeneidade paisagística para o planejamento de diretrizes visando à conservação em regiões do Cerrado. Por sua grande extensão, posição biogeográfica e complexidade de relevo e tipos de hábitat, a EESGT tem papel fundamental para a preservação e conhecimento da diversidade de répteis do Cerrado.

A assembléia de abelhas (Hymenoptera, Apidae) de uma área restrita de campos naturais do Parque Estadual de Vila Velha, Paraná e comparações com áreas de campos e cerrado

A assembléia de abelhas (Hymenoptera, Apidae) de uma área restrita de campos naturais do Parque Estadual de Vila Velha, Paraná e comparações com áreas de campos e cerrado. Foram realizadas coletas sistemáticas de abelhas em uma área restrita no Parque Estadual de Vila Velha, Paraná, no período de outubro de 2003 a setembro de 2004. Essa amostragem visou gerar subsídios para comparações entre áreas de campo dentro do Parque e com outras áreas de vegetação aberta brasileiras. A área de estudo possui cerca de quatro hectares e foi subdividida em quatro subáreas contínuas e com o mesmo perímetro. As abelhas em flores e em vôo foram capturadas com auxílio de rede entomológica. Foram coletados 1.459 espécimes pertencentes a 122 espécies de abelhas. Estas espécies estão distribuídas em 51 gêneros, 20 tribos e cinco subfamílias. As plantas visitadas correspondem a 93 espécies, pertencentes a 62 gêneros e 29 famílias. Neste estudo e em outro estudo realizado anteriormente em outra área do Parque foram coletadas 222 espécies sendo 74 espécies em comum as duas áreas e uma soma de 148 espécies restritas a uma ou outra área. Ainda, registros históricos de abelhas para Vila Velha elevam a riqueza conhecida para 261 espécies. O índice de similaridade de Morisita entre as áreas foi de 0,50 quando utilizadas as plantas como variáveis e 0,88 quando utilizados gêneros e espécies de abelhas, revelando uma notável heterogeneidade. Comparações entre as áreas do Parque Estadual de Vila Velha e áreas de campos e cerrado foram realizadas através do índice de similaridade e da análise de correspondência. Foram observados dois agrupamentos fortemente evidentes, referentes aos campos e ao cerrado. A análise de correspondência sugere que alguns gêneros podem ser relacionados a determinadas formações vegetais. Esse estudo indica que a fauna de abelhas de Vila Velha é composta principalmente por gêneros relacionados às áreas de campos, porém com presença de elementos de cerrado.