Antônio Fernando de Souza Queiroz

Determination of total arsenic and arsenic (III) in phosphate fertilizers and phosphate rocks by HG-AAS after multivariate optimization based on Box-Behnken design

In the present paper, a procedure for the determination of total arsenic and arsenic (III) in phosphate fertilizers and phosphate rocks by slurry sampling (SS) with hydride generation atomic absorption spectrometry (HG-AAS) is proposed. Arsenic (III) is determinated directly and total arsenic is determinated after reduction reaction. The procedure was optimized for the flow rate of NaBH(4), NaBH(4) and hydrochloric acid concentrations using a full two-level factorial and also a Box-Behnken design. Slurry preparation with hydrochloric acid in an ultrasonic bath allowed the determination of arsenic (III) with limits of detection and quantification of 0.1 and 0.3 microg L(-1), respectively. The precision of results, expressed as relative standard deviation (RSD), was always lower than 3%. The accuracy of this method was confirmed by analysis of certified sediment reference materials, while the procedure also allows for calibration using aqueous external standards. This method (SS/HG-AAS) was used to determine total arsenic and arsenic (III) in two phosphate rock samples and two phosphate fertilizer samples. In these samples, total arsenic concentrations varied from 5.2 to 20.0 mg kg(-1), while As (III) concentrations varied from 2.1 to 5.5 mg kg(-1), in agreement with published values. All samples were also analyzed using acid digestion/HG-AAS. Both, a paired t-test and a linear regression model demonstrated no significant difference (95% CL) between the results obtained using these two sample preparation procedures.

Phytoremediation in mangrove sediments impacted by persistent total petroleum hydrocarbons (TPH’s) using Avicennia schaueriana

This study evaluated the efficiency of Avicennia schaueriana in the implementation of phytoremediation compared with intrinsic bioremediation in mangrove sediments contaminated by total petroleum hydrocarbons (TPHs). The experiment was conducted for 3months at a pilot scale under conditions similar to a mangrove: the dynamics of the tides were simulated, and physical, chemical, microbiological and biogeochemical parameters were monitored. After the 90 days, it was found that the phytoremediation was more efficient in the degradation of the TPHs compared to bioremediation, reducing the initial concentration of 32.2-4.2 mg/g. A. schaueriana was also more efficient in mediating the degradation of different fractions of hydrocarbons, achieving a removal efficiency of 87%. The microbiological results consisted of a higher growth in the model with the plants, demonstrating the phytostimulation ability of the plants. Finally, the experiment showed that phytoremediation is a promising alternative in mangrove impacted by oil.

Fonte e grau da contaminação por hidrocarbonetos policíclicos aromáticos (HPAs) de baixa massa molecular em sedimentos da baía de Todos os Santos, Bahia

Todos os Santos Bay, located in Reconcavo Bahiano, is the largest navigable bay of Brazil. Its seafront has about 450 km and is covered by extensive mangroves and recent sediments. This study was undertaken to evaluate the possibility of chronic environmental impact induced by 50 years of exposure to the local petroleum industry. Polycyclic Aromatic Hydrocarbons (PAHs) from pyrolitic sources were identified and quantified in the total concentration range 1 - 408.629 ng.g -1 . The highest contents of PAHs were found in the harbors and transportation areas. Phe/An and An/(An+Phe) molecular indices were used to identify the PAH contamination source in the studied sampling stations. It was found that the pyrolitics PAHs concentrations were comparable with those of contaminated zones (refinery and extraction areas). In general, the Todos os Santos Bay sampling sites were contaminated, due to the petroleum trade on an individual scale along the Bay, and also waste oils from motorized boats.

Speciation analysis of inorganic antimony in airborne particulate matter employing slurry sampling and HG QT AAS

The present paper proposes an analytical procedure for speciation analysis of inorganic antimony in airborne particulate matter using slurry sampling and hydride generation atomic absorption spectrometry (HG QT AAS). During the antimony determination, a quartz T tube cell was heated to approximately 900 °C using air–acetylene flame. The optimization step was performed by employing full two-level factorial and Box–Behnken designs involving the following factors: flow rate and concentration of sodium tetrahydroborate and hydrochloric acid concentration, having as chemometric response absorbance. Using the optimized conditions, the method employing slurry sampling allows for the determination of total Sb and Sb(III) with limits of quantification of 0.3 and 0.2 μg L−1, respectively. The precision, expressed as a relative standard deviation (%RSD), was always lower than 6.2%. The accuracy was confirmed by analysis of a certified reference material of atmospheric particulate matter urban dust furnished by National Institute of Standards & Technology. This method was used to determine total antimony and antimony(III) in four particulate matter samples collected in Bananeira Village, Bahia State, Brazil. In these samples, total antimony concentrations varied from 4.32 to 4.60 ng m−3, and Sb(III) concentrations varied from 0.33 to 0.67 ng m−3.

Estudo mineralógico do sedimento de manguezal da baía de Camamu-Ba

The Camamu Bay, an important fishing, mining and tourist site, is located at the South Coastal Region of the State of Bahia, Brazil. This large water body is surrounded by extensive mangrove forest and has been the object of many geo-environmental studies. The objective of this work is to present partial results of one of these studies, a mineralogical evaluation in the sediments of the Camamu Bays mangrove. This semi-quantitative study showed that in the stations next the mining zone the sediment is rich in quartz, barite and clays, with small percentage of pyrite and jarosite. However, for the majority of the stations, the mineralogy is predominantly: quartz and clays, with a variety of percentages of barite, pyrite and crude gypsum in some stations. The results obtained in this work indicated that, for this studied mangrove, the mineralogical composition of the sediments seems to be intimately related to the geologic processes occurring locally. The processes can be: either weathering processes in situ, or man made processes with posterior carriage; or through mineralogical modifications in situ, resulting from the physical-chemical conditions operating at the environment.

Sources and distribution of polycyclic aromatic hydrocarbons (PAHs) and organic matter in surface sediments of an estuary under petroleum activity influence, Todos os Santos Bay, Brazil

The present study evaluated the origin and distribution of polycyclic aromatic hydrocarbons (PAHs) and the organic matter (OM) in the surface sediment of the São Paulo River estuary, Todos os Santos Bay (TSB), Brazil. The samples were collected in the rainy (CP1) and the dry (CP2) seasons. We analyzed the 16 PAHs from the United States Environmental Protection Agency (US EPA) priority pollutant list, total organic carbon (TOC), total nitrogen (N), and stable carbon isotope (δ13C). The total concentration of PAHs ranged from 11.45±1.28 to 1825.35±107.96ngg-1, while TOC ranged from 3.8 to 27.7gkg-1. CP1 showed the highest concentrations for all parameters. The δ13C ratio indicated terrigenous OM (-23.81 to -26.63‰). The TOC/N ratio (C/N) indicated transitional OM (12.32 to 24.39), in addition to the continental origin. The diagnostic ratios of PAHs origin revealed only pyrolytic source, although close to areas with a history of petroleum contamination.

Multivariate optimization of a procedure employing microwave-assisted digestion for the determination of nickel and vanadium in crude oil by ICP OES

This work presents the optimization of a sample preparation procedure using microwave-assisted digestion for the determination of nickel and vanadium in crude oil employing inductively coupled plasma optical emission spectrometry (ICP OES). The optimization step was performed utilizing a two-level full factorial design involving the following factors: concentrated nitric acid and hydrogen peroxide volumes, and microwave-assisted digestion temperature. Nickel and vanadium concentrations were used as responses. Additionally, a multiple response based on the normalization of the concentrations by the highest values was built to establish a compromise condition between the two analytes. A Doehlert matrix optimized the instrumental conditions of the ICP OE spectrometer. In this design, the plasma robustness was used as chemometric response. The experiments were performed using a digested oil sample solution doped with magnesium(II) ions, as well as a standard magnesium solution. The optimized method allows for the determination of nickel and vanadium with quantification limits of 0.79 and 0.20μgg-1, respectively, for a digested sample mass of 0.1g. The precision (expressed as relative standard deviations) was determined using five replicates of two oil samples and the results obtained were 1.63% and 3.67% for nickel and 0.42% and 4.64% for vanadium. Bismuth and yttrium were also tested as internal standards, and the results demonstrate that yttrium allows for a better precision for the method. The accuracy was confirmed by the analysis of the certified reference material trace element in fuel oil (CRM NIST 1634c). The proposed method was applied for the determination of nickel and vanadium in five crude oil samples from Brazilian Basins. The metal concentrations found varied from 7.30 to 33.21μgg-1 for nickel and from 0.63 to 19.42μgg-1 for vanadium.

Ultrasound assisted extraction for the determination of mercury in sediment samples employing cold vapour atomic absorption spectrometry

An extraction procedure involving ultrasound assisted radiation was proposed for the determination of mercury in river sediment samples using cold vapour atomic absorption spectrometry (CV AAS). The optimization step was performed using a two-level full factorial design, being that the studied factors were thiourea and hydrochloric acid concentrations, time and temperature of sonication and absorbance as the chemometric response. The experimental conditions of the extraction procedure found by optimization were as follows: hydrochloric acid concentration, 4 mol L−1; thiourea concentration, 0.75% (m v−1); sonication time, 20 min and sonication temperature, 60 °C. The validation studies demonstrated that by employing the optimized conditions, the method allows the determination of mercury using an external calibration technique with limits of detection and quantification of 10 and 35 ng L−1, respectively, and precision expressed as a relative standard deviation of 4.31% for a mercury solution with a concentration of 5.00 μg L−1. The limits of detection and quantification calculated for a sample mass of 0.20 g are respectively 1.04 and 3.46 ng g−1. The method accuracy was confirmed by analysis of the certified reference materials: NIST SRM 2709a San Joaquim Soil and BCR 320 Channel sediment. This method was applied for the determination of mercury in five sediment samples collected from the Sao Paulo River (Bahia State, Brazil). The mercury concentrations obtained varied from 13.8 to 38.5 ng g−1. These values are compatible with other data reported in the literature for mercury contents in uncontaminated sediment samples.

GEOCHEMICAL CORRELATIONS BETWEEN PETROLEUM SAMPLES FROM THE POTIGUAR BASIN AND DEFINITION OF THEIR POSSIBLE GENERATING ROCKS

Jeferson Cavalcante Alvesa, Rennan Geovanny Oliveira Araujoa,b,*,#, Eliane Soares de Souzac, Sarah Adriana Rocha Soaresa, José Roberto Cerqueiraa, Karina Santos Garciaa, Antonio Fernando de Souza Queiroza, Maria Goreti Rodrigues Valed e Aline Rocha Borgese Núcleo de Estudos Ambientais, Instituto de Geociências, Universidade Federal da Bahia, Campus de Ondina, Rua Barão de Jeremoabo, s/n – Ondina, 40170-110 Salvador – BA, Brasil Departamento de Química Analítica, Instituto de Química, Universidade Federal da Bahia, Campus Ondina, Rua Barão de Jeremoabo, 147 – Ondina, 40170-115 Salvador – BA, Brasil Laboratório de Engenharia e Exploração de Petróleo, Centro de Ciências e Tecnologia, Universidade Estadual do Norte Fluminense, Rodovia Amaral Peixoto Km 163, Avenida Brennand s/n – Imboacica, 27925-310 Macaé – RJ, Brasil Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-790 Porto Alegre – RS, Brasil Instituto Federal do Paraná, Campus Palmas, 85555-000, Palmas – PR, Brasil

DISTRIBUIÇÃO DE ELEMENTOS TRAÇO EM TECIDOS DE Goniopsis cruentata (LATREILLE, 1803) CAPTURADOS NOS MANGUEZAIS DO SUL DA BAHIA - BRASIL E AVALIAÇÃO DO POTENCIAL DE RISCO NO CONSUMO

DISTRIBUTION OF TRACE ELEMENTS IN TISSUES OF Goniopsis cruentata (LATREILLE, 1803) CAUGHT FROM SOUTH OF BAHIA/ BRAZIL MANGROVES AND POTENTIAL OF RISK ASSESSMENT IN CONSUMPTION. The concentrations of trace metals Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Zn and V were measured in gills, muscle and hepatopancreas of G. cruentata caught from South of Bahia in order to assess the potential health risk by the consumption of mangrove crabs. The highest metal concentrations in gills, and hepatopancreas were Cu, and Zn in muscles, while the lowest metal concentration in three tissues was Cd and Mo. With the results, it is possible to suggest that the high concentrations of some elements, especially of the Cu, may present risks to the Aratu consumers of the mangrove areas studied, or to other populations where these animals may be transported, same for other cities. The mean concentration of Pb in gills in Una and Jequitinhonha is above the value allowed by the legislation, 3,08 μg g and 3,49 μg g, respectively. The concentration of Mn in the females in the three estuaries studied was 1.5 to 4.2 times higher than in the males. In general, detected mean metal concentrations in crab tissues were (in decreasing order) gills > hepatopancreas > muscles. Through the PCA analysis, differentiation between the tissues studied was observed due to its elemental composition. The target hazard quotient (QR) of all trace metals in muscle was less than 1.0 of the provisional tolerable daily intake (IDE) adopted by the USEPA. These results imply that G. cruentata caught from South of Bahia do not have an adverse impact on the consumer health.