Polycyclic aromatic hydrocarbon derivatives onto polar microplastics of polyurethane: equilibrium, thermodynamics, and kinetics of monolayer-multilayer adsorption.

The study of the adsorption of polycyclic aromatic hydrocarbons on microplastics (MPs) has attracted much attention as to how microplastics can act as carriers of these pollutants. Polyurethane (PU) is one of the MPs found in aquatic environments, containing different functional groups it can interact with polar and nonpolar molecules. PAH derivatives (dPAHs) present different properties and thus can be adsorbed by different interactions; thus, this study investigated the adsorption of fluorene (FLN), dibenzothiophene (DBT), dibenzofuran (DBF), and carbazole (CBZ) onto PU MP. The Langmuir, Freundlich, and BET isotherm models were examined, and the BET model best fitted. The adsorption was a nonspontaneous process, exothermic for mono- and multilayer formation for FLN, DBT, and CBZ, and endothermic for DBF monolayer formation. The adsorption monolayer was formed by van der Waals forces, H─bonding, and π─π interactions, while the formation of the multilayer can be explained by π─π and hydrophobic interactions. The pseudo-second-order model proved to be more consistent for the adsorption of dPAHs. The adsorption in artificial seawater shows no significant differences for the monolayer but favored the adsorption multilayer due to the salting-out effect. Due to the existence of several adsorption mechanisms, PU MP interacts with dPAHs in greater quantities when compared to a MP with a simpler structure.

Hybrid organic monolithic column containing MIL-68(Al) for the separation of small molecules by capillary HPLC.

A hybrid organic monolithic column made of poly(lauryl methacrylate-co-1,6-hexanediol dimethacrylate) and the metal-organic framework MIL-68(Al) was prepared for the first time. The column was used in capillary liquid chromatography, both in isocratic and gradient elution modes. Separation performance towards small molecules of different chemical nature (polycyclic aromatic hydrocarbons, alkylbenzenes, phenols, etc.) was studied. Monte Carlo simulations were made to both select the proper precursors to obtain empty metal-organic framework micropores in the monolithic polymer and also, to analyze the potential free access of the studied analytes into the micropores (necessary to improve mass transfer and column efficiency). The hereby synthesized metal-organic framework microcrystals allowed obtaining homogeneous hybrid monolithic columns. Adding of MIL-68(Al) (1030 m2 g-1 BET specific surface area) increased the surface area from 3.9 m2 g-1 for the parent monolith to 18.2 m2 g-1 for the hybrid column containing 8 mg mL-1 of the microcrystals. Chromatographic performance of this new column was evaluated by studying retention factors, resolution, and plate counts at room temperature. Different compounds, not completely resolved in the parent monolith, were partially or completely separated after metal-organic framework addition. Using the monolithic column with only 2 mg mL-1 of MIL-68(Al), five alkylbenzenes were completely separated with very symmetrical peak shapes, resolution factors up to 3.60 and plate counts of 4300 plates m-1 for n-hexylbenzene. This value is higher than those obtained by other authors who used organic monolithic columns with embedded metal-organic frameworks to perform separations at room temperature. Additionally, nine polycyclic aromatic hydrocarbons were partially or completely resolved in gradient elution mode. The hybrid monolithic columns exhibited very good intra-day (%RSD=1.9), inter-day (%RSD=2.6), and column-to-column (%RSD=4.3) reproducibility values. Easy and fast column preparation, and versatility to efficiently separate several compounds of different chemical nature in isocratic and gradient mode, makes this new hybrid column a very good option for the analysis of small molecules in capillary (or nano) HPLC.

Common bean polyphenolic enriched extracts decrease reactive oxygen species induced by heavy metals and polycyclic aromatic hydrocarbons in Hs27 and Hs68 human fibroblasts.

The increase of coarse particulate matter (PM10) due to industrialization and urban sprawl has been identified as a significant contributor to air pollution and a threat to human skin health and premature aging. The objective was to analyze the antioxidant effect of phenolic-enriched extracts (PHE) obtained from black bean (BB) and pinto bean (PB) varieties (Phaseolus vulgaris L.) and pure phenolic compounds (rutin, catechin, and gallic acid) in two human dermal fibroblasts cell lines exposed to PM10. Petunidin-3-O-glucoside was the most abundant anthocyanin, with 57 ± 0.9 mg/g dry extract (DE) in PHE-BB. Gallic acid was the prevalent phenolic acid with 8.2 ± 2.8 mg/g DE in PHE-BB (p < 0.05). Hs27 and Hs68 cell lines were exposed to PM10 (100 µg/mL) to induce oxidative stress; PHE-BB reduced it by 69% ± 12 and PHE-PB by 80% ± 5 relative to PM10 treatment (p < 0.05). Delphinidin-3-O-glucoside showed the highest binding affinity in adenosine monophosphate-activated protein kinase (AMPK) with -9.0 kcal/mol and quercetin-3-D-galactoside with -6.9 kcal/mol in sirtuin 1 (Sirt1). Rutin increased the expression of Sirt1 by 30% (p < 0.05) in the Hs27 cell line treated with PM10. Common bean extracts can potentially reduce oxidative stress induced by PM10 in human dermal fibroblasts.

Deep eutectic solvent for the extraction of polycyclic aromatic compounds in fuel, food and environmental samples.

Polycyclic aromatic compounds (PACs) encompass a wide variety of organic analytes that have mutagenic and carcinogenic potentials for human health and are recalcitrant in the environment. Evaluating PACs levels in fuel (e.g., gasoline and diesel), food (e.g., grilled meat, fish, powdered milk, fruits, honey, and coffee) and environmental (e.g., industrial effluents, water, wastewater and marine organisms) samples are critical to determine the risk that these chemicals pose. Deep eutectic solvents (DES) have garnered significant attention in recent years as a green alternative to traditional organic solvents employed in sample preparation. DES are biodegradable, have low toxicities, ease of synthesis, low cost, and a remarkable ability to extract PACs. However, no comprehensive assessment of the use of DESs for extracting PACs from fuel, food and environmental samples has been performed. This review focused on research involving the utilization of DESs to extract PACs in matrices such as PAHs in environmental samples, NSO-HET in fuels, and bisphenols in foods. Chromatographic methods, such as gas chromatography (GC) and high-performance liquid chromatography (HPLC), were also revised, considering the sensibility to quantify these compound types. In addition, the characteristics of DES and advantages and limitations for PACs in the context of green analytical chemistry principles (GAC) and green profile based on metrics provide perspective and directions for future development.

Biomolecular condensates of Chlorocatechol 1,2-Dioxygenase as prototypes of enzymatic microreactors for the degradation of polycyclic aromatic hydrocarbons.

Polycyclic aromatic hydrocarbons (PAHs) are molecules with two or more fused aromatic rings that occur naturally in the environment due to incomplete combustion of organic substances. However, the increased demand for fossil fuels in recent years has increased anthropogenic activity, contributing to the environmental concentration of PAHs. The enzyme chlorocatechol 1,2-dioxygenase from Pseudomonas putida (Pp 1,2-CCD) is responsible for the breakdown of the aromatic ring of catechol, making it a potential player in bioremediation strategies. Pp 1,2-CCD can tolerate a broader range of substrates, including halogenated compounds, than other dioxygenases. Here, we report the construction of a chimera protein able to form biomolecular condensates with potential application in bioremediation. The chimera protein was built by conjugating Pp 1,2-CCD to low complex domains (LCDs) derived from the DEAD-box protein Dhh1. We showed that the chimera could undergo liquid-liquid phase separation (LLPS), forming a protein-rich liquid droplet under different conditions (variable protein and PEG8000 concentrations and pH values), in which the protein maintained its structure and main biophysical properties. The condensates were active against 4-chlorocatechol, showing that the chimera droplets preserved the enzymatic activity of the native protein. Therefore, it constitutes a prototype of a microreactor with potential use in bioremediation.

Investigating the Solvent Effects on Binding Affinity of PAHs-ExBox4+ Complexes: An Alchemical Approach.

Polycyclic aromatic hydrocarbons (PAHs) are polluting agents, produced naturally or artificially, widely dispersed in the environment and potentially carcinogenic and immunotoxic to humans and animals, mainly for marine life. Recently, a tetracationic box-shaped cyclophane (ExBox4+) was synthesized, fully characterized, and revealed to form host-guest complexes with PAHs in acetonitrile, demonstrating the potential ability for it to act as a PAHs scavenger. This work investigates, through Molecular Dynamics (MD) simulations, the binding affinity between different PAHs and ExBox4+ in different solvents: chloroform (nonpolar), acetonitrile (polar protic), and water (polar protic). An alchemical method of simultaneous decoupling-recoupling (SDR) was used and implemented in a newly developed Python program called GHOAT, which fully automates the calculation of binding free energies and invokes the AMBER 2020 simulation package. The results showed that the affinity between ExBox4+ and PAHs in water is much larger than in organic media, with free energies between -5 and -20 kcal/mol, being able to act as a PHAs scavenger with great potential for applications in environmental chemistry such as soil washing. The results also reveal a significant correlation with the experimental available ΔG values. The methodology employed presents itself as an important tool for the in silico determination of binding affinities, not only available for charged cyclophanes but also extensible to several other HG supramolecular systems in condensed media, aiding in the rational design of host-guest systems in a significant way.

Polycyclic aromatic hydrocarbons in cachaças packed in bottles of polyethylene terephthalate.

Cachaça is a beverage of great cultural and economic importance for Brazil. It is made up of several substances that are responsible for the flavor of the beverage. Countless substances of a toxic nature can also be present, such as polycyclic aromatic hydrocarbons (PAHs). These contaminants are commonly found in beverages and food. They have been studied because their toxicity is related to their mutagenic and carcinogenic properties, and they pose a risk to human health. The PAHs can be formed in cachaça during different stages of processing. In this work, the presence of PAHs (naphthalene, acenaphene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, acephenylene, and benzo[a]pyrene) was investigated during the storage of the beverage in plastic containers. Thus, samples from five producers of cachaça in the state of Minas Gerais were stored for up to 8 months in polyethylene terephthalate (PET) packaging from three different manufacturers. Samples stored for 4 and 8 months were analyzed by high-performance liquid chromatography, and 10 PAHs (naphthalene, acenaphene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, acephenylene, and benzo[a]pyrene) were identified and quantified. An increase in PAH concentration in cachaça samples with the storage time in plastic containers was observed. The three different packages contributed to the contamination of the cachaça samples with different PAHs. The highest concentration (approximately 11.0 µg L-1 ) of fluorene was observed in sample A from the three packages and during the two storage times. Thus, it can be inferred that the storage of cachaça in bottles of PET is inadequate for maintaining the quality of the beverage. PRACTICAL APPLICATION: Therefore, it can be inferred from the results of the analysis that PET packages are sources of PAHs, and the storage time in these packages contributed to the increase in the concentration of these contaminants in the beverage. These results suggest that a review of the legislation regarding the use of PET packaging for beverage storage is necessary, as these compounds are carcinogenic.

Planetary Minerals Catalyze Conversion of a Polycyclic Aromatic Hydrocarbon to a Prebiotic Quinone: Implications for Origins of Life.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in astrochemical environments and are disbursed into planetary environments via meteorites and extraterrestrial infall where they may interact with mineral phases to produce quinones important for origins of life. In this study, we assessed the potential of the phyllosilicates montmorillonite (MONT) and kaolinite (KAO), and the enhanced Mojave Mars Simulant (MMS) to convert the PAH anthracene (ANTH) to the biologically important 9,10-anthraquinone (ANTHQ). All studied mineral substrates mediate conversion over the temperature range assessed (25-500°C). Apparent rate curves for conversion were sigmoidal for MONT and KAO, but quadratic for MMS. Conversion efficiency maxima for ANTHQ were 3.06% ± 0.42%, 1.15% ± 0.13%, and 0.56% ± 0.039% for MONT, KAO, and MMS, respectively. We hypothesized that differential substrate binding and compound loss account for the apparent conversion kinetics observed. Apparent loss rate curves for ANTH and ANTHQ were exponential for all substrates, suggesting a pathway for wide distribution of both compounds in warmer prebiotic environments. These findings improve upon our previously reported ANTHQ conversion efficiency on MONT and provide support for a plausible scenario in which PAH-mineral interactions could have produced prebiotically relevant quinones in early Earth environments.

Nucleus-Independent Chemical Shift (NICS) as a Criterion for the Design of New Antifungal Benzofuranones.

The assertion made by Wu et al. that aromaticity may have considerable implications for molecular design motivated us to use nucleus-independent chemical shifts (NICS) as an aromaticity criterion to evaluate the antifungal activity of two series of indol-4-ones. A linear regression analysis of NICS and antifungal activity showed that both tested variables were significantly related (p < 0.05); when aromaticity increased, the antifungal activity decreased for series I and increased for series II. To verify the validity of the obtained equations, a new set of 44 benzofuran-4-ones was designed by replacing the nitrogen atom of the five-membered ring with oxygen in indol-4-ones. The NICS(0) and NICS(1) of benzofuran-4-ones were calculated and used to predict their biological activities using the previous equations. A set of 10 benzofuran-4-ones was synthesized and tested in eight human pathogenic fungi, showing the validity of the equations. The minimum inhibitory concentration (MIC) in yeasts was 31.25 µg·mL-1 for Candida glabrata, Candida krusei and Candida guilliermondii with compounds 15-32, 15-15 and 15-1. The MIC for filamentous fungi was 1.95 µg·mL-1 for Aspergillus niger for compounds 15-1, 15-33 and 15-34. The results obtained support the use of NICS in the molecular design of compounds with antifungal activity.

Optimized PAH/Folic acid layer-by-layer films as an electrochemical biosensor for the detection of folate receptors.

Folate receptor alpha (FR-α) is a glycoprotein overexpressed in tumor cell surfaces, especially in gynecologic cancers, and can be used as a biomarker for diagnostics. Currently, FRα is quantified by positron emission tomography (PET) or fluorescence imaging techniques. However, these methods are costly and time-consuming. We report on the development of an electrochemical biosensor for FRα detection based on the use of nanostructured layer-by-layer (LbL) films as modified electrodes. Multilayer films were deposited on indium tin oxide (ITO) electrodes by the alternately assembling of positively charged polyallylamine hydrochloride (PAH) and negatively charged folic acid (FA), used as the biorecognition element. UV-vis and FTIR spectroscopies revealed the successful PAH and FA adsorption on ITO. Devices performance was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The [PAH/FA] films presented a good reproducibility (RSD of 1.12%) and stability when stored in the Tris-HCl solution (RSD 6.7%). The biosensor electrochemical response exhibited a linear relationship with FRα concentration in the range from 10 to 40 nM. The limit of detection reached for CV and EIS measurements were 0.7 and 1.5 nM, respectively. As a proof-of-concept, we show that the devices can differenciate tumor cells from healthy cell, showing an excellent selectivity. The biosensor device based on [PAH/FA] films represents a promising strategy for a simple, rapid, and low-cost cancer diagnosis through FRα quantification on the surface of cancer cells.

Database of Nuclear Independent Chemical Shifts (NICS) versus NICSZZ of Polycyclic Aromatic Hydrocarbons (PAHs).

In the present contribution, we have developed a database, called the FAR-database, where the acronym FAR stands for Fused Aromatic Rings, which presents the results of nuclear independent chemical shifts calculations, NICS(0), NICS(1), NICS(0)ZZ, and NICS(1)ZZ, of 660 neutral benzenoid-PAHs and cyclopenta-fused PAHs. The FAR-database provides NICS data of aromaticity of PAHs that could be used in data science and machine learning. To the best of our knowledge, no such database is available in the literature. The importance of this database lies in its potential to transform data into insight and knowledge. Additionally, a new visual representation of the NICS aromaticity pattern, based on the magnitude of the NICS value, is presented. Nowadays calculations of NICS(0)ZZ or NICS(1)ZZ have become popular methods to evaluate aromaticity of systems. By looking at all the 660 systems in the FAR-database, it becomes evident that NICS(0), NICS(1), and NICS(1)ZZ present similar NICS aromaticity patterns for most of the systems. But the NICS aromaticity patterns found with NICS(0)ZZ in many cases do not agree with the NICS aromaticity patterns found with NICS(0), NICS(1), and NICS(1)ZZ. There are cases where the NICS(0)ZZ aromaticity pattern does not show an aromatic character at all. From XY NICS scan at planes from Z = 0 to Z = 1, it is found that as the Z-height is increased, the π-electron ring current effects are dominant, and the σ-bonding contributions are diminished. Therefore, it is recommended here to compute NICS(1)ZZ instead of NICS(0)ZZ when analyzing NICS of PAHs.

Characterization of atmospheric and soil polycyclic aromatic hydrocarbons and evaluation of air-soil relationship in the Southwest of Buenos Aires province (Argentina).

Sixteen polycyclic aromatic hydrocarbons (PAHs) proposed by the US EPA as priority were analyzed in air and soil samples in the Southwest of Buenos Aires, Argentina, in order to study the levels, distribution, sources and fugacity ratios of PAHs, evaluating the relationship between them. For this, 10 passive air samplers (XAD-2® resin) were deployed along the area and replaced three-monthly from January to December 2015. PAHs were analyzed through gas chromatography -mass spectrometry (GC-MS). Results obtained showed that total PAHs levels (∑16) ranged from 27.97 to 1052.99 ng m-3 and from 52.40 to 2118.34 ng. g-1 d.w. for air and soil samples, respectively. The highest air- PAHs levels were registered in Bahía Blanca city (1052.99 ng. m-3, d.w.) an urban-industrial site, while the highest soil-PAHs levels were found in La Vitícola (2118.34 ng. g-1, d.w.), a rural location closed to a high traffic national route. For all sites the highest levels were observed during the winter; however, both spatial and temporal variations were only statistically significant for certain specific PAHs. Diagnostic ratios + PCA, determined dominance of pyrolytic sources. Further, data showed that source of PAHs could be attributed to vehicular and industrial emissions (observed in all periods), biomass combustion (linked mainly to warm period) and domestic emissions (linked mainly to cold period). Finally, fugacity ratios resulted <1, indicating that soil and air samples were not in equilibrium for the majority of PAHs determining a net tendency of air PAHs towards deposition while soil acted principally as a sink.

Trace metals and PAHs in topsoils of the University campus in the megacity of São Paulo, Brazil.

The aim of this study is to discuss the concentration distribution, composition and possible sources of trace metals and 13 PAHs in topsoils of the University campus, in the city of São Paulo, the largest city of South America. Mineralogy and granulometry of topsoils (0-10 cm) samples, were determined and As, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, Sb, V, Zn, Hg, Pt, Pd and PAHs concentrations were quantified in the bulk fraction. The average clay content of soils was 221±61.8 g kg-1 and total carbon was low (mean of 25 g kg-1). Concentrations of metals were generally lower than the reference value established by the São Paulo State Environmental Agency and other studies in the São Paulo urban area, except for Cd, Ni, Pb, Cr and Zn. The mean concentration of the sum of 13 PAHs was 0.33 mg kg-1 and fluorene, indeno(1,2,3-cd)pyrene, anthracene, pyrene and benzo(ghi)perylene were the most abundant compounds. PAHs and trace metals variability were constrained in PMF analysis and showed an association with exhaust and non-exhaust vehicular emissions. The results also pointed out a spatial pattern in the campus area related to traffic conditions and intensity and terrain slope.

Respiratory health assessment and exposure to polycyclic aromatic hydrocarbons in Mexican indigenous population.

Indoor air pollution is an important risk factor for the generation of lung diseases in developing countries. The indigenous population is particularly susceptible to be exposed to the mixture of pollutants from the biomass burning, among them, polycyclic aromatic hydrocarbons (PAHs). The objective of this study was to assess respiratory health and exposure to PAHs in indigenous populations of the Huasteca Potosina in Mexico. The urinary metabolite 1-hydroxypyrene (1-OHP) was evaluated by HPLC with fluorescence detector, the forced expiratory volume in one second (FEV1) and the FEV1/FVC ratio (forced vital capacity) by spirometry in the Teenek indigenous adult population of the communities from Tocoy (TOC), Xolol (XOL), and Tanjajnec (TAN). A total of 134 subjects participated in the study: 64 from TOC, 30 from XOL, and 40 from TAN; in all the communities, high percentages of overweight and obesity were presented (from 50 to 73%). The average hours of firewood usage per year were 281.06, 284.6, and 206.6 in TOC, XOL, and TAN, respectively. The average of the three communities of the % FEV1 post-bronchodilator was 86.1%. There were identified from 4.5 to 6.6% and from 12.5 to 15.5% of spirometric obstructive and restrictive patterns respectively, in all communities. The highest exposure levels reported as median were found in TOC (1.15 µmol/mol of creatinine) followed by TAN (0.94 µmol/mol of creatinine) and XOL (0.65 µmol/mol of creatinine). Considering the magnitude of the indigenous population exposed to pollutants from the biomass burning and the possible effects on respiratory health, it is important to design strategies that mitigate exposure and evaluate the effectiveness through biological monitoring and effects.

Presence and Spatial Distribution of Polynuclear Aromatic Hydrocarbons (PAHs) in Groundwater of Merida City, Yucatan, Mexico.

The karstic aquifer of Yucatan features a high permeability, therefore, all contaminants placed in the soil surface, can reach it through infiltration along with the rain water. The purpose of the present study is to determine the spatial distribution of the aromatic hydrocarbons in the underground water of Merida City. Fifty wells inside the city were sampled. The sampling took place during the dry season, from October 2007 to March 2008. Liquid-liquid Hydrocarbon extraction was performed using hexane and purification was made by previously packed chromatography columns. Regarding the occurrence of polynuclear aromatic hydrocarbon (PAHs) traces, 28 water samples (56%) contained residues of these compounds. The following PAHs presented the highest concentrations: benzo(a)anthracene y benzo(k)fluoranthene 13.26 and 7.88 µg L-1 respectively. Only three of the sampled wells showed levels above those allowed by EPA and WHO norms. The origin of these compounds is mainly pyrogenic.

Determination of polycyclic aromatic hydrocarbons and their nitrated and oxygenated derivatives in coffee brews using an efficient cold fiber-solid phase microextraction and gas chromatography mass spectrometry method.

Polycyclic aromatic hydrocarbons (PAHs) are food contaminants; besides, their oxygenated (oxy-PAHs) and nitrated (nitro-PAHs) derivatives have also been detected in some foods. This is worrying because these derivatives may be more toxic than PAHs. This study presents a new method for the determination of PAHs and their oxygenated and nitrated derivatives in coffee brew. The analytes were extracted by cold fiber solid phase microextraction (CF-SPME) with analysis by gas chromatography/mass spectrometry. The developed method presented good precision with intra-assay and inter-assay, ranged from 4.5 to 16.4%, and from 9.8 to 19.8%, respectively. Recovery ranged from 82.1 to96.3% and linearity showed good adjustment presenting determination coefficients (R2) from 0.980 to 0.999. The limits of quantification ranged from 0.025 to 0.224 µg L-1. The proposed method is simple, versatile, allows simultaneous extraction of PAHs, nitrated and oxygenated derivatives and was successfully applied to the analysis of commercial coffee samples. Benzo(k)fluoranthene, benzo(b)fluoranthene, pyrene, acenaphthylene and acenaphthene are the most abundant PAHs found in samples. In addition, 5,12-naphthacenequinone was the most abundant oxy-PAH and 1-nitropyrene was the most abundant nitro-PAH.

Simultaneous Extraction of Pesticides and Polycyclic Aromatic Hydrocarbons in Brazilian Cachaça Using a Modified QuEChERS Method Followed by Gas Chromatography Coupled to Tandem Mass Spectrometry Quantification.

A modified QuEChERS method was optimized for simultaneous extraction of 93 pesticides and 6 polycyclic aromatic hydrocarbons (PAHs) in cachaça. The procedure employed 20 mL of sample, 10 mL of dichloromethane, 1 g of NaCl, and 6 g of MgSO4. The methods were validated in accordance with pesticide tolerances set by the National Health Surveillance Agency of Brazil and government guidelines of Brazil and the European Union. The linearity of all curves was adequate, with calculated tr higher than the critical value, at the 95% confidence level. For pesticides, recoveries ranged between 86.7 and 118.2%, relative standard deviation (RSD) ≤ 20%, at least at two concentration levels, and limit of detection (LOD) and limit of quantitation (LOQ) were 2.5 and 10.0 µg L-1, respectively. For PAHs, recoveries ranged between 84.8 and 111.5%, RSD was between 6.2 and 27.3%, LOD and LOQ were 0.25 and 1.0 µg L-1, respectively. The combined standard uncertainty was lower than 50% of the relative expanded uncertainty value at concentration levels of greater relevance in both methods. Analyses of five commercial samples detected the presence of 9 pesticides (10.0-128.0 µg L-1) and 6 PAHs (2.0-4.0 µg L-1), indicating the need for a specific legislation for Brazilian cachaça.

Methodology to examine polycyclic aromatic hydrocarbons (PAHs) nitrated PAHs and oxygenated PAHs in sediments of the Paraguaçu River (Bahia, Brazil).

Conventional methods for determination of polycyclic aromatic compounds (PACs) in sediments usually require large sample sizes (grams) and solvent volumes (at least 100 mL) through the employment of Soxhlet extraction, which is both time (hours) and energy consuming, among other disadvantages. We developed a new analytical protocol for the determination of PACs in sediments using microextraction, which requires small sample masses (25 mg), 500 µL of acetonitrile-dichloromethane mix and sonication for 23 min, followed by GC-MS analysis. The method was validated using the certified reference material SRM 1941b - NIST organic marine sediment, as well as internal deuterated standards. Seventeen PAHs, seven nitro-PAHs and one quinone were detected and quantified. The mean concentrations were 90.4 ng g-1 for PAHs, 179.2 ng g-1 for nitro-PAHs and 822.5 ng g-1 for quinones. The proposed method showed good sensitivity, linearity, precision and accuracy for the determination of PAC in sediments samples.

Polycyclic aromatic hydrocarbons degradation by marine-derived basidiomycetes: optimization of the degradation process

ABSTRACT Pyrene and benzo[a]pyrene (BaP) are high molecular weight polycyclic aromatic hydrocarbons (PAHs) recalcitrant to microbial attack. Although studies related to the microbial degradation of PAHs have been carried out in the last decades, little is known about degradation of these environmental pollutants by fungi from marine origin. Therefore, this study aimed to select one PAHs degrader among three marine-derived basidiomycete fungi and to study its pyrene detoxification/degradation. Marasmiellus sp. CBMAI 1062 showed higher levels of pyrene and BaP degradation and was subjected to studies related to pyrene degradation optimization using experimental design, acute toxicity, organic carbon removal (TOC), and metabolite evaluation. The experimental design resulted in an efficient pyrene degradation, reducing the experiment time while the PAH concentration applied in the assays was increased. The selected fungus was able to degrade almost 100% of pyrene (0.08 mg mL-1) after 48 h of incubation under saline condition, without generating toxic compounds and with a TOC reduction of 17%. Intermediate metabolites of pyrene degradation were identified, suggesting that the fungus degraded the compound via the cytochrome P450 system and epoxide hydrolases. These results highlight the relevance of marine-derived fungi in the field of PAH bioremediation, adding value to the blue biotechnology.

Polycyclic aromatic hydrocarbons degradation by marine-derived basidiomycetes: optimization of the degradation process.

Pyrene and benzo[a]pyrene (BaP) are high molecular weight polycyclic aromatic hydrocarbons (PAHs) recalcitrant to microbial attack. Although studies related to the microbial degradation of PAHs have been carried out in the last decades, little is known about degradation of these environmental pollutants by fungi from marine origin. Therefore, this study aimed to select one PAHs degrader among three marine-derived basidiomycete fungi and to study its pyrene detoxification/degradation. Marasmiellus sp. CBMAI 1062 showed higher levels of pyrene and BaP degradation and was subjected to studies related to pyrene degradation optimization using experimental design, acute toxicity, organic carbon removal (TOC), and metabolite evaluation. The experimental design resulted in an efficient pyrene degradation, reducing the experiment time while the PAH concentration applied in the assays was increased. The selected fungus was able to degrade almost 100% of pyrene (0.08mgmL-1) after 48h of incubation under saline condition, without generating toxic compounds and with a TOC reduction of 17%. Intermediate metabolites of pyrene degradation were identified, suggesting that the fungus degraded the compound via the cytochrome P450 system and epoxide hydrolases. These results highlight the relevance of marine-derived fungi in the field of PAH bioremediation, adding value to the blue biotechnology.