Vânia Palmeira Campos

Amostragem passiva de poluentes atmosféricos: aplicação ao SO2

The passive sampling technique has been widely used for many years in the measurement of personal exposure to pollutantes in the workplace. In recent years the technique has been used too for measurements in ambient air. In the specific case of SO2 a variety of passive samplers have been described in the literature. The great number are diffusive samplers and some few are permeation samplers. They are basically of two types: badge and tube-type. However there are more than 10 variations in relation to the sampler dimensions, diffusion barriers and pollutant sorption medium. The technique trend to be very used in the near future with samplers able to reach very low detection limits, proposing a viable option for monitoring specific species at urban, regional and global scales.

Avaliação e identificação de parâmetros importantes para a qualidade de corpos d'água no semiárido baiano. Estudo de caso: bacia hidrográfica do rio Salitre

Objective of this work was identifying superficial water quality parameters, significant to semi-arid hydrographic basins, minimizing costs of water monitoring. The Salitre river basin, an important sub-basin of the Sao Francisco river, was used as a case study. STD, Cl-, DO, BOD, pH, NO3-, PO43-, Al, Cu, Fe, Mn, Ni and Pb were considered the most significant parameters, with concentration levels found in some stretches of the basin not compliant with the current legislation. Some of the Salitre river basin sediments may represent a risk to the quality of the water body in relation to levels of nickel and zinc.

Métodos de amostragem e análise para compostos reduzidos de enxofre atmosférico

This work presents a review of sampling and analytical methods that can be applied to atmospheric traces of reduced sulphur compounds (RSC) in the atmosphere. Sampling methodology involving discontinuous methods with preconcentration is mostly used. For the most part, adsorption on solids and cryogenic capture are applied as a procedure. The analysis of these compounds has been done mainly by gas chromatography with FPD, fluorescence and spectrophotometry. Advantages and disadvantages of the methodologies are also mentioned in this paper, aiming to guide the reader towards the most appropriate choice of a sampling and analytical method for RSCs.

Laboratory validation of a passive sampler for SO2 atmospheric monitoring

The performance of a passive sampler was tested under exposure in Teflon chamber. The SO2 trapped in impregnated filter with 1.0 x 10-2 mol L-1 Na2CO3 solution was extracted in ultrasound bath with H2O2 solution for 15 min and determined as SO42- by ion chromatography. The sampler presented good performance except for air in total stillness condition (0 m s-1), for very short exposure periods (0.5 h), for atmosphere with O3 > 150 mg m-3 and for high concentrations of reduced sulfur compounds. The relative humidity of the air (20 - 80%) and the exposure to zero concentration did not affect the sampler performance. It showed stability for one month at 4 oC or for one week at about 25 oC. Its precision varied within 3.5 and 23% depending of the SO2 concentration and the accuracy varied from 91 to 100%.

Inorganic and organic contaminants in drinking water stored in polyethylene cisterns

This work evaluated the presence of contaminants in stored rainwater in 36 polyethylene tanks installed in two rural communities of the semiarid of Bahia, Brazil. Carbonyl compounds were analyzed by High Performance Liquid Chromatography (HPLC-UV), BTEX (Benzene, Toluene, Ethylbenzene and Xylenes) by gas chromatoghaphy (GC-FID), and trace elements by inductively coupled plasma optical emission spectrometry (ICP-OES). Seven carbonyl compounds were quantified including acrolein (<3-115 µg L-1), which is considered a potent mutagenic agent, above the potability limit in 75% of the cases. Trace elements such as copper, zinc, barium, aluminum and lead, more frequently found, were also quantified, and lead (<0,56-99 µg L-1) was above the tolerable limit for drinking water of 10 μg L-1 in 73% of the cases. The results show that the stored water in polyethylene cisterns in the Brazilian semiarid region does not present satisfactory conditions for human consumption.

Influence of the Transport of Sea Spray on the Salinization of the Semiarid Region Waters (Bahia, Brazil)

The sea spray can be transported to long distances, reaching the semiarid regions. In this work, the rainwater and the atmospheric particulate matter were characterized by investigating the presence of sea spray in the atmosphere of the semiarid region of Bahia, Brazil, aiming to study the influence of its transport on the salinization of the waters of the region. Stable isotopes of deuterium and oxygen-18 were also determined in the rain as environmental tracers, evaluating the isotopic ratios O/O and D/H. The atmosphere of the region suffers marine influence, as well as resuspended soil particles and anthropogenic sources. The results demonstrate that the amount of sea spray which reaches the region is insufficient to interfere at the groundwater composition and the cause of its salinization should be attributed to the local geology and the evaporation and salt concentration process due to the high temperatures found in the region.

Determination of agrochemical multi-residues in grapes. Identification and confirmation by gas chromatography-mass spectrometry

The valley of the Sao Francisco river, northeastern Brazil, is home to the major mango and grape producers of Brazil, many of which already export to foreign markets. Grape cultivation in the Sao Francisco River Valley is arguably the most important fruit cultivation in the region. The products are assessed using stringent criteria through audits based on international standards, which specify the maximum levels of agrochemical residues in the fruits. The objective of this study was to adapt and validate the effective Quick, Easy, Cheap, Effective, Robust and Safe (QuEChERS) method for the determination of agrochemical multi-residues in grapes. Agrochemicals of interest included fungicides, insecticides, and herbicides, including groups of compounds such as pyrethroids, triazoles, dicarboximides, quinones, tetrazines, dinitroanilines, carbamates, organochlorine, and organophosphate. The grapes were collected weekly over a period of 6 months on farms and markets in the region (approximately 140 samples). Sample preparation involved ultra-turrax extraction, centrifugation and clean-up with a mixture of inorganic salts and polymers, enabling the identification and confirmation by gas chromatography-mass spectrometry (GC-MS) of 80 agrochemical multi-residues in grapes. The results showed QuEChERS to be an accurate and effective method, with detection limits (0.0025–0.02 mg kg−1) and quantification limits (0.01–0.22 mg kg−1) within the requirements of both domestic standards (Ministry of Agriculture) and international standards for food, including Codex Alimentarius and others. The repeatability was tested at intermediate levels of limits of quantification with seven replicates, presenting variation coefficients in the range 2.1–15%. Recovery percentages were satisfactory, and within the range 70–125%.

Phytochemical Profile of Seed Extracts of Plants Typical of the Brazilian Semiarid and their Potential Application in Brackish Water Desalination

The phytochemical profile of typical seeds from semiarid areas of Bahia was explored. The desalination capacity of the seeds discovered in previous studies considered the seeds potentially suitable for desalination of water. Coals composed of crushed seeds of umbu (Spondias tuberosa Arr. Cam.) and umburana (Amburana cearensis A. C. Sm.) were prepared by heating at 250 oC. As the desalination process using these materials involves ion exchange besides adsorption, it became necessary to study their chemical composition to check the possibility of transferring undesirable chemical species to the water during the contact between material and water. None of the tested metabolites were found in umbu coal, which enabled its use in desalination. However, the presence of coumarin and alkaloids in the umburana seeds coal indicated that this material is not suitable for that use.

Desenvolvimento de dispositivo caseiro para dessalinização de água salobra a partir de sementes de umbu (Spondias tuberosa Arruda Câmara)

The goal of this work was to develop a homemade device to desalinate brackish water, using biological material like seeds from different plant species of the semi arid regions. Umbu seeds (Spondias tuberosa Arruda Câmara) were found to be the most appropriate material, removing a higher quantity of salt from the water compared to the other tested materials. The salt content in 1 L of brackish water typical of the region can be removed with only 1 g of the material, if the water is heated to 50 °C and it may also lower the water hardness, achieving drinking water standards.