Application of a PLA/PBAT/Graphite sensor obtained by electrospinning on determination of 2,4,6-trichlorophenol.

The widespread use of pesticides requires effective detection and quantification tools to improve monitoring of environmental quality. Electrochemical sensors offer a fast and sensitive response, and can also be optimized by combining several constituents and techniques, including biodegradable materials, being useful in the determination of chemical agents from environmental samples. Here, we produced a polymer-based sensor for 2,4,6-trichlorophenol determination, through electrospinning of poly(lactic acid)/poly(butylene adipate-co-terephthalate) (PLA/PBAT) blend with graphite. The graphite-containing fibres were thermally treated and wetted in mineral oil, thus forming a paste, used as an electrode in the electrochemical sensor. The thermal analysis indicated a disorganization of the polymeric chains between the aromatic carbon chain of the PBAT polymer, resulting in a material with low enthalpy, lower crystallinity and greater thermal degradability after insertion of graphite in polymeric fibres. NIR spectra revealed changes related to the carbonyls of the polymeric ester groups. Cyclic voltammetry and square wave voltammetry techniques were applied to study the electrochemical behaviour of developed sensor. The thermal treatment of graphite-containing fibres increased the adhesion surface in which occurs the adsorption of the analyte on the electrode, which improved the peak current in the electrochemical tests. The PLA/PBAT/Graphite sensor applied to determination of 2,4,6-TCP presented the detection and quantification limits of 7.84 × 10-8 mol L-1 (0.0155 mg L-1) and 2.36 × 10-7 mol L-1 (0.0466 mg L-1) with a linearity response of 1.00 × 10-7 mol L-1 and 2.00 × 10-6 mol L-1 with correlation coefficient of 0.993 (r2).

Plasticizer concentration effect on films and coatings based on poly(vinyl alcohol) and cationic starch blends.

Films based on poly(vinyl alcohol) (PVA) and cationic starch (CS) were combined with different percentages of sorbitol (S; 15.0, 22.5, and 30.0% w v-1) to assess the effect of plasticizer on the films. Spectroscopic analyses confirmed the interaction between them. However, micrographs indicated the formation of sorbitol crystals on the surface of the films, especially at higher sorbitol concentrations. The blends presented low water vapor transmission rate values, reaching (7.703 ± 0.000) g h-1 m-2 (PVA75CS25S15), and low solubility values for the films containing higher CS amounts. The lack of statistical differences in most parameters suggests that no significant gain comes from increasing the amount of sorbitol at percentages higher than 15%. As a coating, the blend PVA75CS25S15 successfully decreased the loss of moisture content in acerolas by 1.15 times (compared to the control), confirming the suitability of this matrix as a fruit coating.

Electrospinning in personal protective equipment for healthcare work.

Protection in many service areas is mandatory for good performance in daily activities of workers, especially health areas. Personal protective equipment (PPE) is used to protect patients and health workers from contamination by harmful pathogens and body fluids during clinical attendance. The pandemic scenario caused by SARS-CoV-2 has shown that the world is not prepared to face global disease outbreaks, especially when it comes to the PPE of healthcare workers. In the last years, the world has faced a deficiency in the development of advanced technologies to produce high-quality PPE to attend to the exponential increasing demand. Electrospinning is a technology that can be used to produce high-quality PPE by improving the protective action of clothing. In the face of this concern, this manuscript presents as focus the potential of electrospinning to be applied in protective clothing. PPE mostly used by healthcare workers are also presented. The physico-chemical characteristics and production processes of medical textiles for PPE are addressed. Furthermore, an overview of the electrospinning technique is shown. It is important to highlight most research about electrospinning applied to PPE for health areas presents gaps and challenges; thus, future projections are also addressed in this manuscript.

Biosorption of methylene blue by residue from Lentinus crinitus mushroom cultivation.

Conventional textile effluent treatments cannot remove methylene blue, a mutagenic azo dye, and an endocrine disruptor, that remains in the drinking water after conventional water treatment. However, the spent substrate from Lentinus crinitus mushroom cultivation, a waste, could be an attractive alternative to remove persistent azo dyes in water. The objective of this study was to assess the methylene blue biosorption by spent substrate from L. crinitus mushroom cultivation. The spent substrate obtained after mushroom cultivation had been characterized by the point of zero charge, functional groups, thermogravimetric analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. Moreover, the spent substrate biosorption capacity was determined in function of pH, time, and temperature. The spent substrate had a point of zero charge value of 4.3 and biosorbed 99% of methylene blue in pH from 3 to 9, with the highest biosorption in the kinetic assay of 15.92 mg g- 1, and in the isothermal assay of 120.31 mg g- 1. Biosorption reached equilibrium at 40 min after mixing and best fitted the pseudo-second-order model. Freundlich model best fitted the isothermal parameters and each 100 g spent substrate biosorbed 12 g dye in an aqueous solution. The spent substrate of L. crinitus cultivation is an effective biosorbent of methylene blue and an alternative to removing this dye from water, adding value to the mushroom production chain, and supporting the circular economy.

Poly(butylene adipate-co-terephthalate)/Poly(lactic acid) Polymeric Blends Electrospun with TiO2-R/Fe3O4 for Pollutant Photodegradation.

This work aimed to use the electrospinning technique to obtain PBAT/PLA polymer fibers, with the semiconductors rutile titanium dioxide (TiO2-R) and magnetite iron oxide (Fe3O4), in order to promote the photocatalytic degradation of environmental contaminants. The parameters used in the electrospinning process to obtain the fibers were distance from the needle to the collecting target of 12 cm, flow of 1 mL h-1 and voltage of 14 kV. The best mass ratio of semiconductors in the polymeric fiber was defined from a 22 experimental design, and the values obtained were 10% TiO2-R, 1% Fe3O4 at pH 7.0. Polymer fibers were characterized by Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and Fourier Transform Infrared (FTIR) techniques. SEM measurements indicated a reduction in fiber diameter after the incorporation of semiconductors; for the PBAT/PLA fiber, the average diameter was 0.9466 ± 0.2490 µm, and for the fiber with TiO2-R and Fe3O4 was 0.6706 ± 0.1447 µm. In the DSC, DRX, TGA and FTIR analyses, it was possible to identify the presence of TiO2-R and Fe3O4 in the fibers, as well as their interactions with polymers, demonstrating changes in the crystallinity and degradation temperature of the material. These fibers were tested against Reactive Red 195 dye, showing an efficiency of 64.0% within 24 h, showing promise for photocatalytic degradation of environmental contaminants.

Lithium bioaccumulation in Lentinus crinitus mycelia grown in media with different lithium sources and pH values.

Lentinus crinitus bioaccumulates lithium in mycelia, but bioaccumulation may be affected by pH of the culture medium. Lithium is used in clinical practice as a mood stabilizer and antidepressant. This study aimed to assess the effect of culture medium pH and lithium source (LiCl or Li2CO3) on lithium bioaccumulation in vegetative mycelia of L. crinitus grown in malt extract broth. Lentinus crinitus U9-1 was cultured in malt extract broth supplemented with Li2CO3 or LiCl (50 mg L-1 lithium) in the pH range of 3.0 to 6.0. The pH was adjusted using HCl solution. The results showed that medium pH affected mycelial biomass production, lithium bioaccumulation in mycelial biomass, and lithium transfer from the culture medium to mycelial biomass. The effect of lithium source on the bioaccumulation capacity of mycelial biomass varied according to pH. At pH 4.0, both lithium sources stimulated mycelial biomass production compared to the control without the addition of lithium. At pH 5.5, Li2CO3 provided the highest lithium bioaccumulation in mycelial biomass. Lithium transfer from the culture medium to mycelia was highest in Li2CO3-supplemented cultures at pH 4.5. LiCl reduced hyphal width compared with Li2CO3 and the control. However, pH and lithium sources did not affect the formation of clamp connections in hyphae. For the first time, the influence of the pH of the culture medium on lithium bioaccumulation by Lentinus crinitus is reported. Finally, we conclude that the culture medium pH affected lithium transfer and bioaccumulation in mycelial biomass differently depending on the lithium source. Additionally, we report the presence of clamp connections in the hyphae of L. crinitus as an indicator of even growth.

Basidiocarp structures of Lentinus crinitus: an antimicrobial source against foodborne pathogens and food spoilage microorganisms.

Lentinus crinitus basidiocarps are an alternative to antimicrobials, but the stipe (24% basidiocarp) is discarded even with potential antimicrobial activity. This study evaluated the antimicrobial activity of L. crinitus basidiocarp pileus and stipe extracts against foodborne pathogens and food spoilage microorganisms. Basidiocarps of L. crinitus were grown in sugarcane bagasse and rice husks and the pileus and stipe methanolic extract was analyzed by broth microdilution method for antimicrobial activity against eight bacteria and eight fungi. The minimum bactericidal concentration values for pileus and stipe ranged from 0.40 to 0.50 mg mL- 1, for streptomycin from 0.10 to 0.50 mg mL- 1, and for ampicillin from 0.40 to 1.20 mg mL- 1. The minimum fungicidal concentration values for pileus and stipe ranged from 0.06 to 0.60 mg mL- 1, for bifonazole from 0.20 to 0.25 mg mL- 1, and for ketoconazole from 0.30 to 3.50 mg mL- 1. Extracts had bacteriostatic, bactericidal, fungistatic and fungicidal activity against all microorganisms, but with greater efficiency and specificity for some microorganisms. Both pileus and stipe are promising and sustainable alternatives for use in food, agricultural, and pharmaceutical industries.

Iron-enriched mycelia of edible and medicinal basidiomycetes.

Iron bioaccumulation in basidiomycetes is an alternative to recover ferrous sulphate from titanium dioxide pigment production and to produce an iron-enriched mycelial biomass. This study aimed to evaluate iron bioaccumulation capacity in vegetative mycelium of edible and medicinal fungi grown in malt extract liquid medium with different ferrous sulphate contents. Five basidiomycetes were grown in malt extract liquid medium with different iron contents from 0.116 to 100 mg L-1 iron. The iron content of dried mycelial biomass bioaccumulated with iron was determined by flame atomic absorption spectrophotometry. All fungi grew on the iron culture media and the mycelial biomass growth ranged from 3.24 ± 0.65a mg mL-1 to 12.46 ± 0.29 mg mL-1. Iron addition to culture media increased the iron content in the mycelial biomass from 4000-13,000-fold compared with control. Pleurotus ostreatus (2181 ± 218 mg kg-1) presented the greatest iron content in the mycelial biomass, followed by Schizophyllum commune (1769 ± 131 mg kg-1), Agaricus subrufescens (1272 ± 8.84 mg kg-1), and Ganoderma lucidum (840 ± 75 mg kg-1). P. ostreatus, followed by S. commune, and G. lucidum at 90 and 100 mg L-1 iron in the culture medium are the best choices to produce iron-enriched mycelial biomass. This extensive study of several edible and medicinal basidiomycetes grown in different iron contents was effective in recovering ferrous sulphate byproduct and transferring it to mycelium to produce a new nutraceutical food of iron-enriched mycelial biomass.

Electrospun poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) nanofibers for the controlled release of cilostazol.

Drug delivery devices are attractive alternatives to drugs usually orally administrated. Therefore, this work aimed to produce PLA/PBAT-based nanofibers for the controlled release of cilostazol, evaluating the effect of different drug concentrations (20 and 30%) over the properties of the fibers. The fibers were characterized by scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), x-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric (TG/DTG), and mechanical analysis. SEM results indicated a high concentration of drug crystals on the surface of the fibers that contained 20% of cilostazol. These fibers were also thinner, more crystalline, less thermally stable, and less fragile in comparison to the fibers containing 30% of cilostazol, according to the XRD, DSC, TG/DTG, and mechanical results. The controlled release assays indicated that the fibers containing 20% of cilostazol would be attractive for short-term releases, reaching the equilibrium after approximately 6 h, while the ones containing 30% would ensure a slower release (~ 12 h). Despite the differences, both fibers would improve and enhance the efficiency of the treatment, and they would also prevent possible side effects caused by the drug to the gastric system.

Sugarcane biomass colonized by Pleurotus ostreatus for red 4B dye removal: a sustainable alternative.

Biosorption of the red 4B dye was evaluated using non-colonized sugarcane bagasse and colonized by Pleurotus ostreatus. The fungal colonization caused an increase in the acid and phenolic groups, making the biosorbent surface more positive, with lower thermal stability due to decomposition of lignocellulosic compounds, lower pHpcz, and smaller pores. The biosorbents showed better adsorption at pH 2.0 and required 260 min to reach equilibrium. The kinetic data fit the pseudo-second order mathematical model, which predicts strong chemical interaction between adsorbent and adsorbate. The mathematical models that best fit the isothermal data were the combination of Langmuir for low dye concentrations and Freundlich for high dye concentrations in the solution for the non-colonized biosorbent, which predict that adsorption occurs in monolayer and multilayer, respectively. For the colonized biosorbent, the model that best fits the isothermal data (25°C and 40°C) was the Freundlich model, showing that the adsorption for this case occurs in multilayers. Thermodynamic studies (25°C, 40°C and 50°C) show that increasing temperature decreases the biosorption capacity (exothermic process for both biosorbents), and the system shows low spontaneity with increasing concentration. Also, the entropy for non-colonized sugarcane bagasse increases at low concentrations, however after fungal colonization, it decreases for both. In industrial effluent, the non-colonized biosorbent presented a higher biosorption capacity, but fungal colonization demonstrates greater sustainability by initially allowing the production of mushrooms.

Iron biofortification and availability in the mycelial biomass of edible and medicinal basidiomycetes cultivated in sugarcane molasses.

Basidiomycetes can bioaccumulate high iron contents, but there are few studies on iron availability from the mycelial biomass in order to support their use as an iron-enriched fungal food. This study aimed to evaluate the in vitro iron bioaccumulation and availability in the mycelial biomass of edible and medicinal basidiomycetes grown in two distinct culture media. Lentinus crinitus, Ganoderma lucidum, Schizophyllum commune, Pleurotus ostreatus, Pleurotus eryngii, Lentinula edodes, and Agaricus subrufescens were grown in liquid culture medium of malt extract or sugarcane molasses to obtain iron-bioaccumulated mycelial biomass. P. ostreatus was the fungus that most bioaccumulated iron, followed by S. commune, and P. eryngii; they also had the highest mycelial biomass growth and iron transfer from the culture medium to the mycelial biomass. Mycelial iron availability is species-specific, regardless of the culture medium and the iron bioaccumulation capacity of the fungus in the mycelial biomass. Mycelial biomass of S. commune, followed by G. lucidum, P. ostreatus, and P. eryngii, associated with molasses culture medium, are the best choice for the production of iron-enriched mycelial biomass.

Lithium bioaccumulation in Lentinus crinitus mycelial biomass as a potential functional food.

Lentinus crinitus is an important basidiomycete consumed by ethnic groups from the Amazon, commonly found in decomposing trees with high lignolytic and antioxidant activities. Lithium is a mood stabilizer, antiepileptic, antipsychotic, and antidepressant used in clinical practice. This study aimed to evaluate L. crinitus mycelial biomass bioaccumulated with lithium in liquid cultivation medium. The malt extract medium was added from zero to 100 mg L-1 lithium from two lithium sources (Li2CO3 and LiCl). The maximum mycelial biomass production was 7218.89 mg L-1 in the culture medium added with 5 mg L-1 lithium from LiCl. The highest lithium concentration in the mycelial biomass was of 574.72 µg g-1 produced in the culture medium with 25 mg L-1 lithium from Li2CO3. Pearson's correlation showed that Li2CO3 reduces the mycelial biomass and increases lithium bioaccumulation. The maximum translocated lithium from cultivation medium to mycelial biomass was up to 19 or 28% with LiCl or Li2CO3, respectively. Therefore, although Li2CO3 presents greater inhibition on the mycelial biomass production, it promoted greater lithium bioaccumulation in L. crinitus mycelial biomass and resulted in greater yield of lithium translocation. The equivalent daily dose of lithium for psychiatric treatment, without bioavailability studies, could be reached with 97.4 g lithium-enriched mycelial biomass and, based in the literature, for reduction of violence and criminality rates the amount could be reached with 0.24-0.58 mg. Thus, the development of lithium-enriched mycelial biomass could be an alternative functional food.

Biossorção de íons Cr(III) de soluções aquosas sintéticas e efluente de curtume utilizando a macrófita aquática Pistia stratiotes / Biosorption of Cr(III) ions from synthetic aqueous solutions and tannery effluent using the macrophyte Pistia stratiotes

RESUMO O cromo é um metal tóxico amplamente utilizado em processos industriais, por isso a constante preocupação com os efluentes líquidos gerados. Uma vez lançados sem o devido tratamento podem comprometer a qualidade do corpo receptor. Este trabalho teve por objetivo analisar o processo de biossorção na remoção de íons Cr(III) de soluções aquosas sintéticas e efluente de curtume utilizando como biossorvente a macrófita aquática Pistia stratiotes in natura (PN) e quimicamente modificada (PM) com hidróxido de sódio e ácido cítrico. Realizou-se o preparo, a caracterização dos biossorventes e os experimentos de biossorção. Os estudos de equilíbrio indicaram que a capacidade máxima de biossorção foi de 58,16 e 19,80 mg g-1 para PM e PN, respectivamente. Nos testes utilizando efluente bruto de curtume, a remoção de cromo foi de 28,26% para ambos os biossorventes, e no efluente da lagoa de tratamento biológico, a maior taxa de remoção do metal foi obtida pelo biossorvente PM, com 65,44%. Os resultados demonstraram que a utilização de P. stratiotes como biossorvente apresenta-se como uma alternativa eficaz e de baixo custo, porém estudos complementares são necessários a fim de avaliar sua aplicação em escala real.

ABSTRACT Chromium is a toxic metal widely used in industrial processes, so the concern with the liquid effluents generated is constant, that once released without proper treatment can compromise the quality of the receiver body. The study aimed at analyzing the process of biosorption in removing Cr(III) ions of synthetic aqueous solutions and tannery effluent using as biosorbent the Pistia stratiotes macrophyte in natura (PN) and chemically modified (PM) with sodium hydroxide and citric acid. The preparation, characterization of the biosorbents and the experiments of biosorption were performed. Equilibrium studies indicated that the maximum biosorption capacity for PM was 58.16 mg g-1 and 19.80 mg g-1 for PN. In the tests using raw effluent from tannery, chromium removal was 28.26% for both biosorbents, and in the effluent from biological treatment lagoon, the higher rate of metal removal was obtained by biosorbent PM with 65.44%. The results showed that the use of P. stratiotes as biosorbent may be an effective and low-cost alternative and that additional studies are needed to assess its full-scale application.

Bioaccumulation of Lithium (Li2CO3) in Mycelia of the Culinary-Medicinal Oyster Mushroom, Pleurotus ostreatus (Agaricomycetes).

Pleurotus ostreatus is a white-rot mushroom that bioaccumulates metals in basidiocarps and vegetative mycelia. This fungus has been used in soil and water bioremediation of several heavy metals; however, there are few studies of lithium mycelial bioaccumulation for pharmacological use. The aim of this study was to evaluate lithium bioaccumulation in P. ostreatus mycelia grown in a liquid malt extract cultivation medium with Li2CO3 or LiCl. Each lithium source was added to the medium to obtain a concentration of 0, 5, 10, 15, 20, 25, 30, 40, 50, 100, or 200 mg · L-1 lithium. The highest bioaccumulation of lithium in mycelia was 1575.29 µg · g-1 upon treatment with 40 mg · L-1 Li2CO3. P. ostreatus mycelia produce biomass and bioaccumulate both lithium sources, but more lithium bioaccumulates when in the form of Li2CO3. This study provides a prospective for the development of biotechnological products with high aggregate values and alternative ways to deliver lithium and eventually other salts for pharmacological use.

Removal of toxic metals using endocarp of açaí berry as biosorbent.

The effectiveness of açaí endocarp as biosorbent for removal of Cd2+, Pb2+ and Cr3+ from single solute solutions was analyzed. The biomass of açaí endocarp was characterized by scanning electron microscopy, infrared spectroscopy and determining the point of zero charge. The optimum conditions for adsorption process were obtained at solution pH 6.0 for Cd(II) removal, pH 5.0 for Pb(II) removal, and, pH 4.0 for Cr(III). Furthermore, the average optimum efficiency of biosorbent in the optimum conditions was 8, 20 and 12 g of biosorbent per litre of contaminant solution, respectively, for Cd(II), Pb(II) and Cr(III). The best dynamic equilibrium time was reached at 60 min and Langmuir's model had the best fit for Cd(II) and Cr(III) biosorption, indicating a monolayer adsorption. Freundlich's model exhibited the best fit for Pb(II) ion. Elution rates were low, indicating a strong metal interaction with the adsorbent's surface. Thermodynamic parameters showed a spontaneous and endothermal process in the case of Cd(II) and Pb(II) ions, but not for Cr(III) ion, which appears to be an exothermic process. Results show that the use of the açaí biosorbent may be a promising alternative for the remediation of polluted water, due to its low cost and highly availability.

Adsorption mechanism of chromium(III) using biosorbents of Jatropha curcas L.

The removal of Cr3+ from water solutions by biosorbents from the rind, endosperm, and endosperm + episperm of the Jatropha curcas was evaluated. Adsorption tests were performed in batch systems for evaluating the influence of the solution's pH, adsorbent mass, contact time, initial Cr3+ concentrations, and solution temperature during the adsorption process. Kinetic, adsorption isotherm, and thermodynamic studies were performed to investigate the mechanisms that control adsorption. Ideal conditions for the adsorption process included pH of the solution of 5.5 and 8 g L-1 adsorbent mass, within 60 min time contact between adsorbent and adsorbate. Maximum adsorption capacities by Langmuir model for rind, endosperm, and endosperm + episperm of the J. curcas were, respectively, 22.11, 18.20, and 22.88 mg g-1, with the occurrence of chemosorption in mono and multilayers. Results show that the biosorbents obtained from J. curcas have a high potential to recuperate Cr3+ from contaminated water sources.

Investigation on the Performance of Chemically Modified Aquatic Macrophytes-Salvinia molesta for the Micro-Solid Phase Preconcentration of Cd(II) On-Line Coupled to FAAS.

In this study, a new method for the preconcentration of cadmium ions using modified aquatic macrophytes - Salvinia molesta as biosorbent in an on-line preconcentration system coupled to flame atomic absorption spectrometry (FAAS) was developed. The method is based on preconcentration of 20.0 mL sample at pH 3.75 through 35.0 mg of biosorbent at 10.0 mL min-1 and subsequent elution with 0.5 mol L-1 HNO3. A preconcentration factor of 31-fold, linear dynamic range from 5.0 to 70.0 µg L-1 (r = 0.9996) and detection and quantification limits of 0.15 and 0.51 µg L-1 were obtained. The characterization of the biosorbent chemically modified with NaOH and citric acid, was performed through FTIR and SEM measurements. The method precision was found to be 3.97 % and 1.48 % for 5.0 and 60.0 µg L-1 Cd(II) solutions, respectively. The applicability of method was checked by analysis of different kind of water samples and certified reference material.

Ninety-Day Oral Toxicity Assessment of an Alternative Biopolymer for Controlled Release Drug Delivery Systems Obtained from Cassava Starch Acetate.

The large consumption of biodegradable films from cassava starch acetate (FCSA) as ingredients in food and pharmaceutical products requires the assessment of the possible toxicity of these products. The aim of this study was to investigate the toxicity of biodegradable film from cassava starch acetate after oral exposure of Wistar rats for 90 days. The amount of food consumed and the body weight were weekly monitored. Blood and urine samples were obtained for the assessment of serum parameters and renal function. Histopathological analyses in target organs were also performed. No evidence of clinical toxicity in hematological, biochemical, or renal parameters in the FCSA-treated animals was found. In addition, relative organ weight and histopathological evaluations did not differ between groups treated with FCSA and control. Data obtained suggest that the subchronic exposure to FCSA does not cause obvious signs of toxicity in Wistar rats, indicating possible safety of this biofilm.

Crosslinked poly (4-vinylpyridine-ethylene glycol dimethacrylate) used for preconcentration of Cd(II) and its determination by flow injection flame atomic absorption spectrometry.

The main purpose of this research was to synthesize crosslinked poly(4-vinylpyridine-ethylene glycol dimethacrylate) and evaluate its feasibility for highly sensitive and selective determination of Cd in water samples by using flow injection flame atomic absorption spectrometry. The crosslinked polymer, prepared by bulk polymerization, was characterized by FTIR spectrometry and scanning electron microscopy. The flow injection solid-phase method was based on preconcentration of 20.0 mL of sample through 100 mg of the polymer packed into a minicolumn at pH 8.25 using a flow rate of 6.0 mL/min, followed by elution with 1.0 M HNO3. The sample solution parameters influencing the preconcentration behavior of Cd ions, such as pH, buffer concentration, and flow rate, were simultaneously studied and optimized using a Doehlert matrix. Values of 0.10 microg/L, 2.0-210 microg/L, 32.3, 18/h, 9.7/min, and 0.62 mL were obtained for LOD, linear range, preconcentration factor, sample throughput, concentration efficiency, and consumption index, respectively. The effect of the presence of the inorganic cations Pb(II), U(IV), Co(II), Hg(II), Cu(II), As(II), Mg(II), Sb(III), Ni(II), Th(IV), Ba(II), and Ca(II) on the method was studied, and the preconcentration of Cd was observed to have no interference. The accuracy of the method was assessed by analysis of natural water samples using addition and recovery tests and inductively coupled plasma/MS as a reference technique, as well as by analysis of a standard reference material of trace elements in water.

Eficiência da quantificação do chumbo em larvas da família chironomidae em ambiente sujeito a contaminação por chumbo / Efficiency of lead quantification in chironomidae larvae family in an environment unprotected to lead contamination

Metais traço como o chumbo (Pb) são poluentes ambientais muito abundantes devido sua ampla aplicação industrial. Os riscos ao meio ambiente causados pela presença destes elementos têm despertado a atenção das autoridades ambientais para o controle da emissão de poluentes e monitoramento, desta forma, o uso de bioindicadores têm sido constantes na avaliação de impactos ambientais. Os organismos mais comuns utilizados para este propósito são os macroinvertebrados bentônicos, pois estes organismos habitam o fundo deste ambiente durante pelo menos parte de seu ciclo de vida e estão associados a diversos tipos de substratos. O presente trabalho teve como objetivo avaliar a eficiência da quantificação de chumbo em indivíduos da família Chironomidae visando sua utilização como indicadores de presença de chumbo em ambientes aquáticos que recebem descarga aleatória deste elemento. Amostras de quironomídeos e do substrato foram submetidas à solução extratora Mehlich e o chumbo foi quantificado por espectrometria de absorção atômica por chama GBC932. Detectou-se Pb nos indivíduos coletados em ambiente contaminado por este elemento, no entanto são necessários novos delineamentos experimentais para validação do método.

Trace metals, such as lead (Pb), are environmental pollutants are plentiful due its wide industrial application. The risks caused to the environment by the presence of these elements have awakened the attention of environmental authorities to control the emission of pollutants and monitoring, thus the use of biomarkers have been constant in the evaluation of environmental impacts. The most common organisms used for this purpose are benthic macroinvertebrates, since these organisms inhabit the bottom of this environment for at least a part of their life cycle and are associated to several types of substrates. This study aimed to evaluate the effectiveness of quantification of lead in individuals of the family Chironomidae for their use as indicators of the presence of lead in aquatic environments that receive random discharge of this element. Samples of chironomids and substrate were submitted to the Mehlich extraction solution and the lead was measured by a GBC932 flame atomic absorption spectrometer. Pb was detected among individuals collected from Chironomidae family in environment contaminated by this element, however new experimental designs are needed to validate the method.