Caio S.A. Felix’s research while affiliated with Federal University of Bahia and other places

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Publications (17)


Mercury in the Southwestern Atlantic reef-building coral Montastraea cavernosa (Cnidaria, Scleractinia)
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July 2024

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20 Reads

Chemosphere

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Caio Felix

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[...]

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Jailson B de Andrade

Evaluation of contamination of chemical elements in fish samples using human health risk assessment indices

May 2024

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39 Reads

Microchemical Journal

This work reports carcinogenic and non-carcinogenic indices in inorganic assessing contamination in fish samples. In this context, fifty-one sardine samples were commercially acquired in seventeen neighborhoods and were toxicologically evaluated. These samples were washed, frozen, freeze-dried, and digested in a microwave oven. Six chemical elements were quantified using inductively coupled plasma optical emission spectrometry. The average levels on a wet basis expressed as μg g−1, ranged from 0.34 to 2.03 for total arsenic, 0.12 to 4.42 for copper, 0.04 to 0.26 for chromium, 4.61 to 99.39 for iron, 3.73 to 34.99 for zinc, and 0.01 to 4.07 for manganese. The estimated weekly intake, target hazard quotient, maximum safe consumption quantity, and carcinogenic risk indices were applied to the data found, denoting that arsenic levels can cause carcinogenic and non-carcinogenic adverse effects on the health of residents. However, these risks are minimized because the evaluation indices were calculated by total arsenic concentrations. In fish matrices, the arsenic is predominantly arsenobetaine, which has low toxicity. Samples from ten neighborhoods also showed copper concentrations that indicate the likelihood of carcinogenic risks. The chromium, iron, zinc, and manganese levels do not pose any health risks to consumers.


Human health risk assessment of mercury in highly consumed fish in Salvador, Brazil

November 2023

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35 Reads

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3 Citations

Marine Pollution Bulletin

This work reports assessing risks to human health resulting from mercury levels in sardines (Sardinella brasiliensis), which have been highly consumed by the low-income population from Salvador, Brazil. Mercury was determined using the Direct Mercury Analysis (DMA) in fifty-one commercially acquired samples in seventeen neighborhoods. The mercury content on a wet basis ranged from 0.023 to 0.083 μg g− 1 for an average value of 0.039 μg g− 1. The estimated weekly intake (EWI), target hazard quotient (THQ), and maximum safe consuming quantity (MSCQ) were used in the toxicological assessment, and all these indices denoted that this food does not pose any risks to the human health of the population that consumes it. The development of this work was very significant because most sardines sold in Salvador originate from Todos os Santos Bay, which has a history of mercury contamination.



Determination and evaluation of the ecological risk of mercury in different granulometric fractions of sediments from a public supply river in Brazil

May 2023

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17 Reads

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4 Citations

Marine Pollution Bulletin

This work reports the quantification of total mercury in sediments collected in periods with and without rain from the Joanes River, Bahia, Brazil. Determinations were made using Direct Mercury Analysis (DMA), the accuracy of which was confirmed with two certified reference materials. The highest total mercury concentrations were found at the sampling point close to commercial areas and large residential condominiums. On the other hand, the lowest levels were found in the site close to a mangrove region. The geoaccumulation index was applied to the total mercury results, evidencing low contamination in the region studied. The contamination factor showed that of the seven stations investigated, four samples collected in the rainy season showed moderate contamination. The results of the ecological risk assessment were utterly consistent with the contamination factor data. This study showed that the smaller sediment particles concentrate more mercury, corroborating what has been predicted by the adsorption processes.


Figure 6. Response surfaces obtained by the Doehlert design for concentrated nitric acid and pH.
Figure 7. Pareto graphic of the robustness test.
Figure 8. Model of the box used for the acquisition of digital images of the proposed methodology. A: Box; B: lamp 6 W SMD LED white light 6500 k; C: cam; D: sample holder; E: bucket.
RGB values and their respective absorbance values.
Effects of factors and their interactions on the bismuth extraction.

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Synthesis and Application of a New Polymer with Imprinted Ions for the Preconcentration of Uranium in Natural Water Samples and Determination by Digital Imaging
  • Article
  • Full-text available

May 2023

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312 Reads

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7 Citations

Molecules

This work proposes the synthesis of a new polymer with imprinted ions (IIP) for the pre-concentration of uranium in natural waters using digital imaging as a detection technique. The polymer was synthesized using 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Br-PADAP) for complex formation, ethylene glycol dimethacrylate (EGDMA) as a crosslinking reagent, methacrylic acid (AMA) as functional monomer, and 2,2′-azobisisobutyronitrile as a radical initiator. The IIP was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy (FTIR). Uranium determination was performed using digital imaging (ID), and some experimental conditions (sample pH, eluent concentration, and sampling flow rate) were optimized using a two-level full factorial design and Doelhert response surface methodology. Thus, using the optimized conditions, the system allowed the determination of uranium with detection and quantification limits of 2.55 and 8.51 µg L−1, respectively, and a pre-concentration factor of 8.2. All parameters were determined using a 25 mL sample volume. The precision expressed as relative deviation (RSD%) was 3.5% for a solution with a concentration of 50 µg L−1. Given this, the proposed method was used for the determination of uranium in four samples of natural waters collected in the city of Caetité, Bahia, Brazil. The concentrations obtained ranged from 35 to 75.4 μg L−1. The accuracy was evaluated by the addition/recovery test, and the values found ranged between 91 and 109%.

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Determination and human health risk assessment of mercury in fish samples

May 2022

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107 Reads

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24 Citations

Talanta

This work reports the determination of mercury in fish samples purchased at a public market in Belem City, Brazil. The mercury quantification was performed using the DMA method, which allows limits of detection and quantification of 0.004 and 0.012 ng, respectively. Method accuracy was confirmed using a certified reference material of fish protein from (NRCC) National Research Council, Canada. The analyzed species were: Dourada (Brachyplatystoma rousseauxii), Filhote (Brachyplatystoma filamentosum), Pescada Branca (Cynoscion leiarchus), Piramutaba (Brachyplatystoma vaillanti). The mercury contents expressed as wet sample weight varied from 0.078 to 0.150 μg g-1. Afterward, the health risk assessment indices Estimated Weekly Intake (EWI), Target Hazard Quotient (THQ), and Maximum Safe Consuming Quantity (MSCQ) were applied to the analytical data, and the results obtained were exhaustively interpreted and discussed. All the indices demonstrated that the daily consumption of 25 g of these fishes does not pose a risk to the human health of the local population. However, these conclusions are preliminary and should not be used in public policy matters.


Figure 1. Mercury concentration in different ascidian tissue in each site. Blue dots represent each tunic measured, yellow ones represent each hepatopancreas measured, and red ones represent the branchial basket measured. The color lines represent each site's mean mercury concentration in respective colors dots tissue in each site and the black line represent the mercury concentration mean in all tissue samples in the respective site.
Mercury studies in solitary ascidian species
When the Detail of Organism Makes the Difference in the Seascape: Different Tissues of Phallusia nigra Have Distinct Hg Concentrations and Show Differences Resolution in Spatial Pollution

January 2022

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27 Reads

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6 Citations

Journal of the Brazilian Chemical Society

This study indicates the use of Phallusia nigra as a potential biomonitor of mercury contamination. In this way, Hg levels were measured in seawater and different parts of ascidians (tunic, hepatopancreas, and branchial basket) from eight different sites in the Todos os Santos Bay, Salvador-Bahia. The ascidians were lyophilized, weighed, and taken to the DMA-80 (direct mercury analyzer); the method accuracy was confirmed by analyzing the certified material DORM- 4 muscle tissue and MEES-3 marine sediment with a confidence level of 95%. The results were evaluated through the Tukey’s test and it was possible to observe a higher concentration of Hg (82.00-312.7 ng g-1) in the branchial basket, followed by the hepatopancreas (69.67‑130.7 ng g-1) and tunic (21.63-33.27 ng g-1). Thus, the branchial basket was the only tissue capable of identifying spatial differences in pollution between the points.


Fig. 2. Representative diagram of the on-line preconcentration system used for the determination of Hg(II) by CV AFS: P = peristaltic pump; MC = minicolumn packed with IIP; RC = reaction cell; GLS = gas-liquid separator; DC = detection cell; and W = waste. A = preconcentration step and B = elution step. Dotted line = without solution flow.
Comparison between the proposed method and IIP-SPE methods related in literature for preconcentration and determination of mercury(II) employing spectrometric techniques.
On-line solid phase extraction system using an ion imprinted polymer based on dithizone chelating for selective preconcentration and determination of mercury(II) in natural waters by CV AFS

July 2019

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138 Reads

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33 Citations

Microchemical Journal

In the present work is described a new on-line solid-phase extraction system using a novel ion imprinted polymer as adsorbent for the preconcentration and determination of mercury(II) in natural water samples by Cold Vapor Atomic Fluorescence Spectrometry (CV AFS). The ion imprinted polymer was prepared by the improved bulk polymerization technique, occurring in only 3 h, based on mercury(II)-dithizone chelate, using methacrylic acid as monomer, ethylene glycol dimethacrylate as cross-linking reagent, 2,2′‑azobisisobutyronitrile as radical initiator, and dimethyl sulfoxide and acetonitrile as porogen solvents. The obtained polymer was characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Thermogravimetry (TG), Derivative Thermogravimetry (DTG) and X-ray Diffraction (XRD). The on-line system was mounted by the easy coupling the mini-column packed with the Hg²⁺-IIP sorbent to the cold vapor system of the spectrometer. The optimum experimental conditions for the on-line preconcentration system were established employing multivariate methodology (two-level full factorial design and Doehlert matrix). Under the optimized conditions, limits of detection and quantification of 0.02 and 0.06 μg L⁻¹, and preconcentration factor of 29 were obtained for the determination of mercury using the developed on-line system, considering a sample volume of 50 mL. Precision expressed as a relative standard deviation (RSD%) was of 5.2% (n = 7) for a standard solution with mercury(II) concentration of 0.5 μg L⁻¹. Then, the on-line system was applied for the selective preconcentration and determination of mercury (II) in four natural water samples, and addition/recovery tests were performed to evaluate the accuracy of the method. All analyzed samples presented Hg²⁺ concentrations below the limit of quantification of the proposed method and the recovery values found were in range from 90 to 105%.


A green on-line digestion system using 70% hydrogen peroxide and UV radiation for the determination of chromium in beer employing ETAAS

February 2019

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53 Reads

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9 Citations

Microchemical Journal

This work proposes an on-line digestion system employing 70% (w/w) hydrogen peroxide and UV radiation for producing hydroxyl radicals for the determination of chromium in beer samples by electrothermal atomization atomic absorption spectrometry (ETAAS). The digester system consists of a closed wooden box, which is painted black internally, containing a PTFE tube wrapped around a 15 W UV lamp. During the mineralization step, a peristaltic pump is employed to propel the sample solution over the UV lamp. The experimental factors UV irradiation time and hydrogen peroxide volume were optimized using a two-level full factorial design. Degradation curves at different pH conditions demonstrated that the digestion of beer is faster at alkaline pH. The results demonstrated that, in the presence of 70% H 2 O 2 and 15 W UV radiation, 75% of the chromophore species is degraded with an irradiation time of 25 min. The degradation kinetic curves of beer samples under different conditions were also evaluated. The apparent kinetic constant (kapp) found for the process assisted by 70% H 2 O 2 and 15 W UV light was 0.0668 min ⁻¹ (R ² = 0.9936). The on-line digestion procedure with a sample flow rate of 2 mL min ⁻¹ for 45 min allowed the determination of chromium in beer samples by ETAAS, utilizing the external calibration technique, with the analytical line 357.9 nm, in the presence of magnesium as chemical modifier with limits of detection and quantification of 0.86 and 2.90 μg L ⁻¹ , respectively. The method accuracy was confirmed by the analysis of the certified reference material of ERM-CA713 wastewater provided by the European Reference Materials. Six beer samples were digested and the chromium was determined. The contents found varied from 4.26 to 33.28 μg L ⁻¹ . Addition/recoveries tests were also performed to evaluate the accuracy method. The recoveries obtained varied from 93.2 to 96.4%.


Citations (14)


... However, levels of mercury exposure should be regularly monitored as they have occasionally approached safety limits. Also, assessing risks to human health resulting from mercury levels in sardines (Sardinella brasiliensis) by Porto et al. [56] demostrated that THQ ranged from 0.027 to 0.086 (<1.00), showing that the consumption of this food would not pose a health risk to the resident population. The study by Cheraghi et al. [57] showed that although the amount of mercury in the muscle of all the studied fish of the Karun River is less than the international standard, the amount of HQ is higher than 1.00, so the consumption of the mentioned fish would pose risks to the health of the consumers. ...

Reference:

Mercury Contamination in Tigertooth croaker, Otolithes ruber (Teleostei, Sciaenidae), Fish of the Northwestern Persian Gulf, with an Emphasis on Human Health Risk
Human health risk assessment of mercury in highly consumed fish in Salvador, Brazil
  • Citing Article
  • November 2023

Marine Pollution Bulletin

... 15 Wavelength-dispersive X-ray uorescence spectrometry (WDXRF) has a good spectral resolution and allows the direct determination of a wide range of elements, including U and Th. 16,17 Energy-dispersive X-ray uorescence spectrometry (EDXRF) is even more express due to simultaneous determination of the elements, but conventional EDXRF lacks the spectral resolution and sensitivity of WDXRF, also inuenced by the matrix effects; 18 hence, EDXRF is less suitable for Th and U determination. 19,20 Laser-induced breakdown spectrometry (LIBS) 21,22 as well as laser ablation ICP-MS (LA-ICP-MS) [23][24][25] can also provide a direct and rapid determination of the Th and U content in solids with minimal sample preparation. LIBS is suitable for the detection of actinides in the range of several wt% due to its low sensitivity and signicant line overlapping. ...

Automated flow systems for total and isotopic analysis of uranium and thorium in samples of environmental interest – A review
  • Citing Article
  • June 2023

TrAC Trends in Analytical Chemistry

... Human activities and industrialization contribute to environmental pollution, causing problems for humans and living organisms [1,2]. Cadmium and lead are significant environmental pollutants, with cadmium being a toxic element found in rocks, soil, and water [1,[3][4][5]. ...

Determination and evaluation of the ecological risk of mercury in different granulometric fractions of sediments from a public supply river in Brazil
  • Citing Article
  • May 2023

Marine Pollution Bulletin

... Thus, the recovery of thorium from aqueous systems containing thorium or other heavy metals becomes extremely important [14]. Classical separation processes (precipitation, sedimentation, flocculation, ion exchange) can be taken into account [15,16], but modern extractive, adsorptive, and membrane processes can also be approached (Table 1) [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. Table 1. ...

Synthesis and Application of a New Polymer with Imprinted Ions for the Preconcentration of Uranium in Natural Water Samples and Determination by Digital Imaging

Molecules

... This lack of standardization poses a major challenge, as it limits the comparability of results across regulatory bodies. Nonetheless, some ERAs integrate data from both standardized and non-standardized Heavy metal bioaccumulation in Phallusia nigra and Microcosmus exasperatus showed species-dependent preferences for the tissues (tunic or body) where heavy metals tend to accumulate, as well as a pollution-dependent Hepato-Somatic Index, which was lower in polluted regions [149,150]. Similarly, bioaccumulation of heavy metals by the ascidian Styela plicata has been documented [151], leading to reduced cell proliferation, decreased viability, and diminished cytotoxic activity of hemocytes [152,153]. Hemocyte morphological alterations and cell death were also observed in 'in vitro' systems [154]. ...

When the Detail of Organism Makes the Difference in the Seascape: Different Tissues of Phallusia nigra Have Distinct Hg Concentrations and Show Differences Resolution in Spatial Pollution

Journal of the Brazilian Chemical Society

... The trophic level grouping was based on information provided by the authors and according to data compiled in a study from the National Amazon Research Institute [13]. For studies that determined the concentration of Hg species on a dry basis, the values were also converted to a wet basis, assuming that the muscle tissue of the fish analyzed has a moisture content of 80 % [14,15]. ...

Determination and human health risk assessment of mercury in fish samples
  • Citing Article
  • May 2022

Talanta

... Tinggi puncak intensitas mencerminkan sejauh mana intensitas difraksi sinar-X pada sudut tertentu, dengan puncak-puncak yang lebih tinggi menunjukkan partisipasi atom yang lebih besar dalam difraksi, yang dapat digunakan untuk mengidentifikasi kualitas bahan dan mengukur tingkat keteraturan kristal. Sementara itu, lebar puncak memberikan informasi tentang distribusi jarak antar bidang kisi dalam kristal, puncak yang lebih lebar mengindikasikan distribusi lebih besar atau kristal yang kurang teratur, sedangkan puncak yang lebih tajam menunjukkan struktur kristal yang lebih teratur [9]. Gambar [11]. ...

On-line solid phase extraction system using an ion imprinted polymer based on dithizone chelating for selective preconcentration and determination of mercury(II) in natural waters by CV AFS

Microchemical Journal

... An on-line digestion system using UV radiation and hydrogen peroxide was used for the determinations by HR-CS GF AAS/ MAS, considering that this procedure is a good alternative for the pretreatment of rich matrices in organic compounds with low risk of contamination and minimal sample handling. The association of the HR-CS GF AAS/MAS with the UV radiation sample pretreatment had the intention of allowing a method, in agreement with the principles of green chemistry, avoiding the use of concentrated acids and minimizing the generation of residues (Felix et al. 2019). In the procedure, the samples were initially sonicated for 30 min for degassing. ...

A green on-line digestion system using 70% hydrogen peroxide and UV radiation for the determination of chromium in beer employing ETAAS
  • Citing Article
  • February 2019

Microchemical Journal

... However, although the PTEs "total concentration" provides a fair indication of soil contamination in risk assessment studies, the information obtained by total concentration analysis is insufficient for precise risk assessment since PTEs toxicity, bioavailability, and environmental mobility are strongly dependents on its chemical form (Quintanilla-Villanueva et al. 2020;Mourinha et al. 2022;Abdul Rashid et al. 2023). Thus, sequential extraction procedures (SEPs) (Du Laing 2010;Reis et al. 2016;Costa Ferreira et al. 2019;Du et al. 2020;Srithongkul et al. 2020;Mourinha et al. 2022;Wang et al. 2022) can be applied for metal fractioning and speciation according to species mobility by successively applying extraction solutions with increasing reactivity to the same soil sample in a way that the obtained fractions contain species ranging from higher to lower mobility. ...

Speciation analysis of antimony in environmental samples employing atomic fluorescence spectrometry - Review
  • Citing Article
  • November 2018

TrAC Trends in Analytical Chemistry

... Box-Behnken design (BBD) is an important statistical method for multi-system design experiments, modeling, evaluating factors and seeking the best conditions for the desired response value [15,16]. It is helpful to analyze various factors that affect the response value by changing parameters simultaneously through a limited number of experiments [17]. Rais et al. [18] prepared a magnetic copper IIP and used BBD to optimize solid-phase extraction parameters to remove Cu(II). ...

Application of a Novel Ion-Imprinted Polymer to the Separation of Traces of CdII Ions in Natural Water: Optimization by Box-Behnken Design

Journal of the Brazilian Chemical Society