Enhancing biodegradation of aged hydrocarbon-contaminated soils through toluene addition: assessing effects on solid and slurry phase treatments.

The main challenge in treating aged soils highly contaminated with total petroleum hydrocarbons (TPH) is to enhance their bioavailability for microbial degradation. Hydrocarbons in soils undergo chemical changes that make them more resistant to biodegradation. This study investigates toluene's efficacy in enhancing the biodegradation of aged hydrocarbon-contaminated soil containing 292,000 mg TPH kg-1 dry soil. Toluene's effect was compared between solid phase (SOP) and slurry phase (SLP) treatments using a microbial consortium isolated from Cyperus laxus rhizosphere. TPH biodegradation and microbial respiration were measured, the latter to estimate the respiratory quotient (RQ, the ratio between moles of carbon dioxide released and moles of oxygen absorbed during respiration). Toluene significantly accelerated TPH biodegradation in both treatments, achieving ~ 30% higher removal than in a non-solvent control, possibly through improved bioavailability of aromatic compounds and other low molecular weight compounds. According to the RQ analysis, toluene enhanced microbial respiratory processes and hydrocarbon catabolism with higher hydrocarbon mineralization (RQ = ~ 0.5) in both SOP and SLP assays. Our results reveal toluene's potential to increase hydrocarbon availability and microbial degradation efficiency in aged contaminated soils; its use in various bioremediation techniques could be of broad applicability across diverse soil types and pollutants.

Evaluation of different composting systems on an industrial scale as a contribution to the circular economy and its impact on human health.

Due to the production of volatile organic compounds (VOCs), large-scale composting can cause air pollution and occupational health issues. Due to this, it is necessary to determine if the amount generated poses a health risk to plant workers, which can be a starting point for those in charge of composting plant facilities. As a result, the goal of this work is to conduct a thorough analysis of both the physicochemical features and the VOC generation of three large-scale systems. For ten weeks, the three different composting plants were monitored weekly, and VOC identification and quantification were performed using GC-MS gas chromatography. It has been observed that the biggest risk related with VOC formation occurs between the fourth and fifth weeks, when microbial activity is at its peak. Similarly, it has been demonstrated that xylenes and toluene are the ones that are produced in the greatest quantity. Finally, after ten weeks of processing, it was discovered that the material obtained complies with the regulations for the sale of an amendment.Implications: The evaluation and monitoring of the composting processes at an industrial scale is very important, due to the implications they bring. VOCs are produced by the operation of composting facilities with substantial amounts of solid waste, such as the companies in this study. These may pose a health risk to those working in the plants; thus, it is critical to understand where the VOCs occur in the process in order to maintain workers' occupational health measures. This form of evaluation is rare or nonexistent in Colombia, which is why conducting this type of study is critical, as it will provide crucial input into determining when the highest levels of VOC generation occur. These are the ones that may pose a risk at some point, but with proper occupational safety planning, said risk may be avoided. This work has evaluated three composting systems, with different types of waste and mixtures. According to reports, while composting systems continue to produce VOCs and their generation is unavoidable, the potential risk exists only within the plant. These findings can pave the way for the implementation of public policies that will improve the design and operation of composting plants. There is no specific legislation in Colombia for the design and execution of this sort of technology, which allows the use of organic waste.

Volatile organic compounds measured by proton transfer reaction mass spectrometry over the complex terrain of Quintero Bay, Central Chile.

This research provides new evidence regarding the different kinds of air quality episodes, and their underlying mechanisms, that frequently impact the urban area of Quintero Bay in Central Chile, which is located along complex coastal terrain and is surrounded by industries. The monitoring campaign was carried out in January 2022 and encompassed two distinctive meteorological regimes. The first part of the month was dominated by a coastal low centered to the south of Quintero, which resulted in prevailing northerly flow (or weak southerlies) and a deep cloud-topped marine boundary layer. After a 2-3-day transition, the latter collapsed, and a clear-sky regime ensued, which was characterized by a shallow boundary layer and strong southerly winds during the daytime that lasted until the end of the campaign. By using proton transfer reaction time of flight mass spectrometry (PTR-TOF-MS) at a high temporal resolution (1 s), we measured high levels of volatile organic compounds (VOCs) during air quality episodes in real time. The episodes detected were associated with different prevailing meteorological regimes, suggesting that different point sources were involved. In the first episode, propene/cyclopropane, butenes, benzene, toluene and ethylbenzene/xylenes were associated with north and northwesterly weak winds. Complaints associated with hydrocarbon odor were reported. The pollution originated from industrial and petrochemical units located to the north of Quintero, which transport and store natural gas, liquified petroleum gas and oil. The second episode was linked to an oil refinery located south of our measurement site. In this case, high levels of phenol, furan and cresols occurred under strong southwesterly winds. During this event, headaches and dizziness were reported. By contrast, the levels of other aromatic compounds (benzene, toluene, ethylbenzene/xylenes) were lower than in the first air pollution episode.

BTEX profile and health risk at the largest bulk port in Latin America, Paranaguá Port.

Port-related activities have a detrimental impact on the air quality both at the point of source and for considerable distances beyond. These activities include, but are not limited to, heavy cargo traffic, onboard, and at-berth emissions. Due to differences in construction, operation, location, and policies at ports, the site-specific air pollution cocktail could result in different human health risks. Thus, monitoring and evaluating such emissions are essential to predict the risk to the community. Environmental agencies often monitor key pollutants (PM2.5, PM10, NO2, SO2), but the volatile organic carbons (VOCs) most often are not, due to its analytical challenging. This study intends to fill that gap and evaluate the VOC emissions caused by activities related to the port of Paranaguá - one of the largest bulk ports in Latin America - by characterizing BTEX concentrations at the port and its surroundings. At seven different sites, passive samplers were used to measure the dispersion of BTEX concentrations throughout the port and around the city at weekly intervals from November 2018 to January 2019. The average and uncertainty of BTEX concentrations (µg m-3) were 0.60 ± 0.43, 5.58 ± 3.80, 3.30 ± 2.41, 4.66 ± 3.67, and 2.82 ± 1.95 for benzene, toluene, ethylbenzene, m- and p-xylene, and o-xylene, respectively. Relationships between toluene and benzene and health risk analysis were used to establish the potential effects of BTEX emissions on the population of the city of Paranaguá. Ratio analysis (T/B, B/T, m,p X/Et, and m,p X/B) indicate that the BTEX levels are mainly from fresh emission sources and that photochemical ageing was at minimum. The cancer risk varied across the sampling trajectory, whereas ethylbenzene represented a moderate cancer risk development for the exposed population in some of the locations. This study provided the necessary baseline data to support policymakers on how to change the circumstances of those currently at risk, putting in place a sustainable operation.

Solvent-dependent formation kinetics of L,L-diphenylalanine micro/nanotubes.

Investigating the molecular mechanism underlying the aggregation process of amyloid fibers is of great importance both for its implications in several degenerative diseases and for the design of new materials based on self-assembly. In particular, micro/nanotubes of L,L-diphenylalanine have been investigated as a model of amyloid plaques in Alzheimer's disease and also for their broad range of physical properties, e.g., good thermo- and mechanical stability, semiconductivity, piezoelectricity and optical properties. It has been reported that the assembly/disassembly dynamics of L,L-diphenylalanine crystals is influenced by the solvent composition being triggered by evaporation of solvents. In fact the solvatomorphism of this peptide-based nanomaterial is complex and rich attracting great attention. Here we investigated the growing kinetics of the micro/nanotubes of L,L-diphenylalanine in samples prepared with toluene, ethanol, and acetic acid solvents by time-resolved Raman spectroscopy. Our results indicated that the self-assembly in this case competes with the water evaporation process contrary to what is reported by samples prepared with widely used solvent 1,1,1,3,3,3-hexafluoro-2-propanol. We note that exclusively tubular structures (being hollow for the toluene solvent case) were observed. Interestingly our results support the fact that for acetic acid, ethanol, and toluene the micro/nanotube formation process is autocatalytic instead of being nucleation-dominating as reported for samples prepared using solvent 1,1,1,3,3,3-hexafluoro-2-propanol.

Evaluation of Bacillus subtilis as a Tool for Biodegrading Diesel Oil and Gasoline in Experimentally Contaminated Water and Soil.

Benzene, toluene, ethylbenzene and xylene (BTEX) are toxic petroleum hydrocarbons pollutants that can affect the central nervous system and even cause cancer. For that reason, studies regarding BTEX degradation are extremely important. Our study aimed evaluate the microorganism Bacillus subtilis as a tool for degrading petroleum hydrocarbons pollutants. Assays were run utilizing water or soil distinctly contaminated with gasoline and diesel oil, with and without B. subtilis. The ability of B. subtilis to degrade hydrophobic compounds was analyzed by Fourier-Transform Infrared Spectroscopy (FTIR) and gas chromatography. The FTIR results indicated, for water assays, that B. subtilis utilized the gasoline and diesel oil to produce the biosurfactant, and, as a consequence, performed a biodegradation process. In the same way, for soil assay, B. subtilis biodegraded the diesel oil. The gas chromatography results indicated, for gasoline in soil assay, the B. subtilis removed BTEX. So, B. subtilis was capable of degrading BTEX, producing biosurfactant and it can also be used for other industrial applications. Bioremediation can be an efficient, economical, and versatile alternative for BTEX contamination.

Caracterização da qualidade do ar atmosférico na Cidade de São Paulo para compostos do grupo BTEX (benzeno, tolueno, etilbenzeno e xilenos), utilizando amostradores passivos / Characterization of atmospheric air quality in the City of São Paulo for compounds of the BTEX group (benzene, toluene, ethylbenzene and xylenes), using passive samplers

A presença de compostos do grupo BTEX, no ar atmosférico de grandes centros urbanos como a cidade de São Paulo é proveniente principalmente de emissões veiculares e demais fontes como as industriais. A exposição a estes compostos, principalmente quando inalados, podem causar sérios efeitos adversos a saúde humana, especialmente o composto benzeno que possui propriedades cancerígenas. Desta forma, a presente pesquisa teve objetivo realizar uma caracterização da qualidade do ar atmosférico na cidade de São Paulo utilizando amostradores passivos para quantificação de compostos do grupo BTEX. Foram selecionadas 5 áreas na cidade conforme dados de tráfego destas regiões e de acordo com o perfil de uso e ocupação do solo. Adicionalmente, foi selecionada uma área como background, com interferência mínima de emissões veiculares ou industriais. Ao todo foram realizadas 3 campanhas de amostragem no entre os anos de 2020 e 2021. O período de coleta de cada campanha foi de 21 dias e na sequência as amostras foram enviadas para análise química em laboratório através do método USEPA-TO17, de 1999 com a utilização de dessorvedor térmico acoplado à um cromatógrafo de gás e um espectrômetro de massas. Foram quantificadas concentrações de BTEX em todas as áreas selecionadas, com destaque para as concentrações de benzeno cuja variação foi de 1,2µg/m3 a 13,5µg/m3, e média de 4,6µg/m3, considerando as 3 campanhas e todas as áreas. Dentro as áreas avaliadas, os pontos localizados no bairro de Santo Amaro apresentaram as maiores concentrações de BTEX, seguido dos pontos no Jaguaré, Mooca, Pinheiros e Paraíso. A campanha realizada no inverno de 2021 apresentou as maiores concentrações tendo influência das condições meteorológicas características desta estação como também influência do aumento do número de veículos circulando na cidade decorrente da diminuição do distanciamento social necessário por conta da pandemia da COVID-19. Os tratamentos estatísticos utilizados nesta pesquisa, especialmente as ferramentas PCA e PMF, concluíram que a principal contribuição para a presença dos BTEX no ar atmosférico são as emissões veiculares, principalmente para os veículos movidos a gasolina.

The presence of compounds from the BTEX group in the atmospheric air of large urban centers such as the city of São Paulo comes mainly from vehicular emissions and other sources such as industrial ones. Exposure to these compounds, especially when inhaled, can cause serious adverse effects on human health, especially the compound benzene, which has carcinogenic properties. Thus, the present research aimed to carry out a characterization of the atmospheric air quality in the city of São Paulo using passive samplers to quantify compounds of the BTEX group. Five areas were selected in the city according to traffic data from these regions and according to the profile of land use and occupation. Additionally, an area was selected as a background, with minimal interference from vehicular or industrial emissions. In all, 3 sampling campaigns were carried out between the years 2020 and 2021. The collection period of each campaign was 21 days and then the samples were sent for chemical analysis in the laboratory using the USEPA-TO17 method, from 1999 with the use of a thermal desorber coupled to a gas chromatograph and a mass spectrometer. BTEX concentrations were quantified in all selected areas, especially benzene concentrations which ranged from 1.2µg/m3 to 13.5µg/m3, and an average of 4.6µg/m3, considering the 3 campaigns and all areas. Within the evaluated areas, the points located in the Santo Amaro neighborhood had the highest concentrations of BTEX, followed by the points in Jaguaré, Mooca, Pinheiros and Paraíso. The campaign carried out in the winter of 2021 showed the highest concentrations influenced by the meteorological conditions characteristic of this season as well as the influence of the increase in the number of vehicles circulating in the city due to the decrease in the social distance necessary due to the COVID-19 pandemic. The statistical treatments used in this research, especially the PCA and PMF tools, concluded that the main contribution to the presence of BTEX in the atmospheric air are vehicular emissions, especially for gasoline-powered vehicles.

Pyrolysis-GCMS of Spirulina platensis: Evaluation of biomasses cultivated under autotrophic and mixotrophic conditions.

Microalgae are autotrophs and CO2 fixers with great potential to produce biofuels in a sustainable way, however the high cost of biomass production is a challenge. Mixotrophic growth of microalgae has been presented as a great alternative to achieve economic sustainability. Thus, the present work reports the energetic characterization of S. platensis biomasses cultivated under autotrophic (A) and mixotrophic conditions using cheese whey waste at different concentrations, 2.5 (M2.5), 5.0 (M5) and 10.0% (M10), in order to analyze the potential production of valuable chemicals and bio-oil by TGA/DTG and Py-GC/MS. The biochemical compositions of the studied biomasses were different due to the influence of different culture mediums. As the whey concentration increased, there was an increase in the carbohydrate content and a decrease in the protein content, which influenced the elemental composition, calorific value, TGA and volatile compounds evaluated by Py-GC/MS at 450°C, 550°C and 650°C. Sample M10 had lower protein content and formed a smaller amount of nitrogenates compounds by pyrolysis at all temperatures evaluated. There was a reduction of 43.8% (450º), 45.6% (550ºC) and 23.8% (650ºC) in the formation of nitrogenates compounds in relation to sample A. Moreover, the temperature also showed a considerable effect in the formation of volatile compounds. The highest yields of nitrogenates compounds, phenols and aromatic and non-aromatic hydrocarbons were observed at 650ºC. The oxygenated, and N and O containing compounds decreased as the temperature increased. Hydrocarbons such as toluene, heptadecane and heneicosane were produced by S.platensis pyrolysis, which makes this biomass attractive for production of high quality bio-oil and valuable chemicals. Therefore, the results showed that it is possible to decrease the formation of nitrogen compounds via manipulation of growth conditions and temperature.

Microbial production of toluene in oxygen minimum zone waters in the Humboldt Current System off Chile.

Expansion of oxygen minimum zones in the world's oceans is likely to enhance the production of anaerobic metabolites by marine microorganisms. Here we show that toluene is present throughout the year in shelf waters of the upwelling ecosystem off Concepción (36° S), Chile, and it is a product of microbial anaerobic metabolism. The intra-annual variability in toluene concentrations is consistent with seasonal variability in the strengths of suboxic equatorial and oxygenated subantarctic water masses. Laboratory incubations of oxygen minimum zone water showed microbial production of toluene in the absence of O2. Toluene concentrations were elevated (up to 96 nM) in deeper O2-depleted waters and followed a seasonal pattern in oceanographic conditions. There is evidence to hypothesize that microbial production of toluene could be a homeostatic biochemical mechanism to thrive in the more acidic oxygen minimum zone waters. On the other hand, evidence indicates that microbial anaerobic degradation of toluene may be a source of NO2- by partial denitrification, as shown for aquifer sediments. Since toluene production was not detected in incubations under aerobic conditions, we hypothesize that oxygen minimum zone waters export toluene to surrounding oxygenated waters. Expansion of hypoxia in the ocean will certainly enhance the production and export of anaerobic metabolites by marine microorganisms.

Catalytic Transformation of Triglycerides to Biodiesel with SiO2-SO3H and Quaternary Ammonium Salts in Toluene or DMSO.

SiO2-SO3H, with a surface area of 115 m2·g-1, pore volumes of 0.38 cm3·g-1 and 1.32 mmol H+/g, was used as a transesterification catalyst. Triglycerides of waste cooking oil reacted with methanol in refluxing toluene to yield mixtures of diglycerides, monoglycerides and fatty acid methyl esters (FAMEs) in the presence of 20% (w/w) catalyst/oil using the hydrophilic sulfonated silica (SiO2-SO3H) catalyst alone or with the addition of 10% (w/w) co-catalyst/oil [(Bun4N)(BF4) or Aliquat 336]. The addition of the ammonium salts to the catalyst lead to a decrease in the amounts of diglycerides in the products, but the concentrations of monoglycerides increased. Mixtures of (Bun4N)(BF4)/catalyst were superior to catalyst alone or Aliquat 336/catalyst for promoting the production of mixtures with high concentrations of FAMEs. The same experiments were repeated using DMSO as the solvent. The use of the more polar solvent resulted in excellent conversion of the triglycerides to FAME esters with all three-catalyst media. A simplified mechanism is presented to account for the experimental results.

Unique volatile metabolite signature of sinonasal inverted papilloma detectable in plasma and nasal secretions.

BACKGROUND: Sinonasal inverted papilloma (SNIP) is a benign neoplasm with aggressive features, including a high recurrence rate and a propensity for malignant transformation. Accurate diagnosis with complete resection and the need for close long-term surveillance is widely accepted as standard management. In this study, we investigate whether SNIP produces a unique volatile metabolite signature, which may ultimately lead to a novel approach to diagnose and monitor SNIP. METHODS: Whole blood and nasal secretions from patients with SNIP and healthy age-, sex-, and smoking-status-matched controls, were collected. There were 56 blood samples and 42 nasal secretion samples collected. The volatile metabolite signature of SNIP plasma and nasal secretion samples were compared with those of healthy controls using chromatography. RESULTS: Seventy-two volatiles were identified in plasma samples. Multivariate analysis of variance results, even when controlled for smoking status, indicated toluene as a significant univariate result with lower levels of toluene identified in SNIP plasma samples than healthy control plasma samples. A linear discriminant analysis (LDA) model for plasma volatiles correctly classified 23 of 24 SNIP patients and 26 of 27 control patients, with a cross-validation error rate of 6.02%. Sixty-nine volatiles were identified in nasal samples. For nasal secretion samples, no single univariate response was significant. The LDA model correctly classified 21 of 21 SNIP patients and 11 of 12 control patients, with a cross-validation error rate of 6.55%. CONCLUSION: This study suggests that SNIP produces a unique, detectable volatile metabolite signature. With further investigation, this can have dramatic clinical implications for diagnosis and monitoring. Although most volatile metabolite studies have investigated solid-organ malignancy, this novel study addresses a benign sinonasal neoplasm by using nasal secretions and plasma as an analysis medium, representing the first such study.

Seasonal and Diurnal Variations of BTEX in Ambient Air from a Site Impacted by the Oil Industry in Southeast Mexico.

Atmospheric concentrations of BTEX were measured in an urban site located in the vicinity of an oil storage-distribution facility in Paraiso, Tabasco, Mexico. Samples were collected during two seasons (nortes 2018 and dry 2019). The relative abundance of BTEX mean concentrations was: toluene (5.24 µg m-3) > ethylbenzene (3.92 µg m-3) > m, p-xylene (3.89 µg m-3) > benzene (2.43 µg m-3). BTEX concentrations had a clear diurnal and seasonal pattern, showing higher levels during the dry season due to differences in wind conditions, rainfall patterns and temperature. Statistical analysis showed significant positive correlations among BTEX, indicating that these compounds had common sources. Interspecies ratios revealed that BTEX were originated from sources beyond vehicular traffic and that they were influenced by the transport of local air masses. The assessment of lifetime cancer risk showed that the population in the study area is at possible risk of developing cancer.

Multivariate Optimization of an SPME Technique for GC-MS Analysis of Urinary BTX.

Volatile organic compounds (VOCs), such as benzene, toluene and xylenes (BTX), are recognized as environmental contaminants due to their acute and chronic toxic effects, and toluene is a substance contained in products used in inhalants. In this way, methods able to determine these substances in non-invasive matrices offer great applicability for assessing acute exposure. In this study, a functionalized polymer, chloropropyltrimethoxysilane/polydimethylsiloxane, was evaluated as a potential material to be used in solid-phase microextraction for the quantification of BTX in urine by gas chromatography coupled to mass spectrometry (GC-MS). The method optimization was performed by using fractional factorial planning 2 (4-1) and the Doehlert's experiment. Desorption time and salinity were the most important factors that impact the sensitivity of the method. Spectroscopic and thermogravimetric characterization demonstrated the functionalization of the material and its thermal stability up to 390°C. This allowed it to be used for ~60 analytical cycles without loss of efficiency. The proposed method demonstrated a satisfactory analytical performance to determine the VOCs studied. The protocol agrees with the principles of green analytical chemistry since the procedure reduced the reagents consumed and wastes generated. It represents a promising tool for acute exposure assessment to BTX since urine tests demonstrated its applicability.

Use of statistical modeling for BTEX prediction in cases of crude oil spill in seawater.

Cases of oil spillage and leakage in marine environments are increasing, and generating a need to quickly assess the presence of these contaminants in seawater. This work aims to estimate the concentrations of benzene, toluene, ethylbenzene and xylenes (BTEX) dissolved in seawater in cases of oil spillage using experimental factorial planning. The study factors were oil °API and oil/seawater contact time after spillage. The models obtained were able to satisfactorily estimate BTEX concentrations, with accuracy greater than 99.3% within the ranges studied, with R² correlation coefficients ranging from 0.992 to 0.997. The models presented forecast efficiency higher than 88%, with low relative errors, ranging from 0.1% to 12%. The concentrations of benzene dissolved in seawater found experimentally with only one hour of spillage, for the two types of oils studied, were higher than allowed by Brazilian legislation, demonstrating real environmental risk in cases of spillage of these types of oil into the sea. These results can corroborate the development of a risk assessment in oil spills within the studied ranges and serve as a useful analytical tool for emergencies.

Benzene, Toluene, Ethylbenzene and Xylene (BTEX) Concentrations in Urban Areas Impacted by Chemical and Petrochemical Industrial Emissions.

The Metropolitan Region of Rio de Janeiro is the second largest urban and industrial region in Brazil. While the south and south-east areas are affected by vehicular emissions, the districts and cities located in the northern area are subjected to industrial emissions and have the poorest air quality of the region. In this study, BTEX concentrations were determined in the District of Irajá, a residential area located in the north of the city of Rio de Janeiro, approximately 25 km from the industrial zone, as well as in the District of Jardim Primavera, in the city of Duque de Caxias. The mean values for total BTEX concentrations were 38.4 ± 11.7 and 44.6 ± 29.3 µg m-3, in Irajá and Jardim Primavera, respectively, which are higher than those previously reported for other areas. The benzene/toluene rates, (approximately 0.5 for both sampling sites), were also higher than typical values that were determined for diesel and gasoline emissions through dynamometer experiments.

Comparative bioaccumulation of PAH and BTEX in Malapterurus electricus (Siluriformes: Malapteruridae) and its enteric parasite, Electrotaenia malopteruri Sampled from Lekki lagoon, Lagos, Nigeria / Bioacumulação comparativa de HAP e BTEX em Malapterurus electricus (Siluriformes: Malapteruridae) e seu parasita entérico, Electrotaenia malopteruri, coletado na lagoa Lekki, Lagos, Nigéria

Contamination of Lekki lagoon by petrogenic chemicals such as polycyclic aromatic hydrocarbons (PAH) and benzene, toluene, ethylbenzene, and xylene (BTEX) has been widely reported. The study was aimed at investigating the bioaccumulation of PAH and BTEX in Malapterurus electricus collected from Lekki lagoon in Lagos, Nigeria. BTEX was analyzed in the intestine, water, and sediment samples using 8260B Agilent 7890B gas chromatograph coupled to a mass spectrometer (GC-MS). While PAHs were tested in the same media using a gas chromatograph coupled to a flame ionization detector (GC-FID). Histopathological analysis of the fish intestine was conducted using haematoxylin and eosin (H&E) stains. Parasite intensity, antioxidant enzymes, and lipid peroxidation activities were investigated in the fish. The parasitic infection detected in Malapterurus electricus was Electrotaenia malopteruri. The parasite showed weak and no depurative capacities for BTEX and PAH respectively. The decrease in superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH) in conjunction with an increase in Malondialdehyde (MDA) characterized relatively higher susceptibility among the male fish. Varieties of tissue injuries increased with the standard length of the fish groups. Results suggest that lengthier and uninfected M. electricus were more susceptible to PAH in Lekki lagoon than the shorter and infected ones. The study demonstrated a promising tendency of the enteric parasite, E. malopteruri to depurate chlorobenzene, ethylbenzene, o-xylene, m+p-xylene, and 1,4-dichlorobenzene from the intestine of its host fish, M. electricus, while PAHs were poorly mediated by the parasite.(AU)

A contaminação da lagoa Lekki por produtos químicos petrogênicos, como hidrocarbonetos aromáticos policíclicos (HAP) e benzeno, tolueno, etilbenzeno e xileno (BTEX), foi amplamente relatada. O estudo teve como objetivo investigar a bioacumulação de HAP e BTEX em Malapterurus electricus, coletados na lagoa Lekki, em Lagos, Nigéria. O BTEX foi analisado no intestino, na água e nas amostras de sedimento usando o cromatógrafo de gás Agilent 7890B 8260B acoplado a um espectrômetro de massa (GC-MS). Já os HAP foram testados no mesmo meio utilizando cromatógrafo gasoso acoplado a detector de ionização de chama (GC-FID). A análise histopatológica do intestino do peixe foi conduzida usando colorações de hematoxilina e eosina (H&E). Intensidade de parasitas, enzimas antioxidantes e atividades de peroxidação lipídica foram investigadas nos peixes. A infecção parasitária detectada em Malapterurus electricus foi Electrotaenia malopteruri. O parasita mostrou fraca e nenhuma capacidade depurativa para BTEX e HAP, respectivamente. A diminuição da superóxido dismutase (SOD), catalase (CAT) e glutationa reduzida (GSH), em conjunto com o aumento do Malondialdeído (MDA), caracterizou a suscetibilidade relativamente maior entre os peixes machos. Variedades de lesões nos tecidos aumentaram com o comprimento padrão dos grupos de peixes. Os resultados sugerem que os M. electricus maiores e não infectados foram mais suscetíveis aos HAP na lagoa Lekki do que os menores e infectados. O estudo demonstrou uma tendência promissora do parasita entérico E. malopteruri de depurar clorobenzeno, etilbenzeno, o-xileno, m + p-xileno e 1,4-diclorobenzeno do intestino de seu peixe hospedeiro, M. electricus, enquanto os HAP foram mal mediados pelo parasita.(AU)

Comparative Bioaccumulation of PAH and BTEX in Malapterurus electricus (Siluriformes: Malapteruridae) and its Enteric Parasite, Electrotaenia malopteruri Sampled from Lekki Lagoon, Lagos, Nigeria / Bioacumulação comparativa de HAP e BTEX em Malapterurus electricus (Siluriformes: Malapteruridae) e seu parasita entérico, Electrotaenia malopteruri, coletado na lagoa Lekki, Lagos, Nigéria

Abstract Contamination of Lekki lagoon by petrogenic chemicals such as polycyclic aromatic hydrocarbons (PAH) and benzene, toluene, ethylbenzene, and xylene (BTEX) has been widely reported. The study was aimed at investigating the bioaccumulation of PAH and BTEX in Malapterurus electricus collected from Lekki lagoon in Lagos, Nigeria. BTEX was analyzed in the intestine, water, and sediment samples using 8260B Agilent 7890B gas chromatograph coupled to a mass spectrometer (GC-MS). While PAHs were tested in the same media using a gas chromatograph coupled to a flame ionization detector (GC-FID). Histopathological analysis of the fish intestine was conducted using haematoxylin and eosin (H&E) stains. Parasite intensity, antioxidant enzymes, and lipid peroxidation activities were investigated in the fish. The parasitic infection detected in Malapterurus electricus was Electrotaenia malopteruri. The parasite showed weak and no depurative capacities for BTEX and PAH respectively. The decrease in superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH) in conjunction with an increase in Malondialdehyde (MDA) characterized relatively higher susceptibility among the male fish. Varieties of tissue injuries increased with the standard length of the fish groups. Results suggest that lengthier and uninfected M. electricus were more susceptible to PAH in Lekki lagoon than the shorter and infected ones. The study demonstrated a promising tendency of the enteric parasite, E. malopteruri to depurate chlorobenzene, ethylbenzene, o-xylene, m+p-xylene, and 1,4-dichlorobenzene from the intestine of its host fish, M. electricus, while PAHs were poorly mediated by the parasite.

Resumo A contaminação da lagoa Lekki por produtos químicos petrogênicos, como hidrocarbonetos aromáticos policíclicos (HAP) e benzeno, tolueno, etilbenzeno e xileno (BTEX), foi amplamente relatada. O estudo teve como objetivo investigar a bioacumulação de HAP e BTEX em Malapterurus electricus, coletados na lagoa Lekki, em Lagos, Nigéria. O BTEX foi analisado no intestino, na água e nas amostras de sedimento usando o cromatógrafo de gás Agilent 7890B 8260B acoplado a um espectrômetro de massa (GC-MS). Já os HAP foram testados no mesmo meio utilizando cromatógrafo gasoso acoplado a detector de ionização de chama (GC-FID). A análise histopatológica do intestino do peixe foi conduzida usando colorações de hematoxilina e eosina (H&E). Intensidade de parasitas, enzimas antioxidantes e atividades de peroxidação lipídica foram investigadas nos peixes. A infecção parasitária detectada em Malapterurus electricus foi Electrotaenia malopteruri. O parasita mostrou fraca e nenhuma capacidade depurativa para BTEX e HAP, respectivamente. A diminuição da superóxido dismutase (SOD), catalase (CAT) e glutationa reduzida (GSH), em conjunto com o aumento do Malondialdeído (MDA), caracterizou a suscetibilidade relativamente maior entre os peixes machos. Variedades de lesões nos tecidos aumentaram com o comprimento padrão dos grupos de peixes. Os resultados sugerem que os M. electricus maiores e não infectados foram mais suscetíveis aos HAP na lagoa Lekki do que os menores e infectados. O estudo demonstrou uma tendência promissora do parasita entérico E. malopteruri de depurar clorobenzeno, etilbenzeno, o-xileno, m + p-xileno e 1,4-diclorobenzeno do intestino de seu peixe hospedeiro, M. electricus, enquanto os HAP foram mal mediados pelo parasita.

[Assessment of exposure to BTEX in vehicle filling stations in Rio de Janeiro, Brazil, and risks to workers' health]. / Avaliação da exposição a BTEX em postos de revenda de combustíveis no Rio de Janeiro, Brasil, e os riscos à saúde do trabalhador.

Gasoline is a complex mixture of substances, including aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylenes (BTEX). These compounds are emitted into the air, with the special relevance of benzene since it is provenly carcinogenic. The study aimed to assess BTEX concentrations in filling stations in the city of Rio de Janeiro, Brazil, and to calculate the cancer risk associated with such exposures. Two types of sampling were performed (stationary and mobile), adapted from methodology n. 1,501 (U.S. National Institute for Occupational Safety and Health) for aromatic hydrocarbons, in six filling stations in the West Zone of Rio de Janeiro. Stationary sampling was done near the fuel pumps, while mobile sampling was done in the breathing zone of the workers (station attendants) as they moved around the station. The samples were analyzed with gas chromatography flame ionization detector. The sampling results were used to calculate the health risk, using the indicators Hazard quotient (HQ) and Cancer risk (CR) to assess the possible non-carcinogenic and carcinogenic effects, respectively, in filling station workers. Environmental concentrations for the most of the BTEX compounds were below the recommended limits, except for benzene, a carcinogenic compound, which displayed concentrations far above the limits, leading to high cancer risk values. The results showed that there are health risks for filling station attendants, especially the risk of developing cancer from excessive exposure to benzene.

A gasolina é uma mistura complexa de substâncias, dentre elas estão hidrocarbonetos como o benzeno, tolueno, etilbenzeno e xilenos (BTEX), sendo esses compostos emitidos para a atmosfera, com destaque ao benzeno, por ser comprovadamente carcinogênico. Objetivamos avaliar as concentrações de BTEX no ar de postos de revenda de combustíveis no Município do Rio de Janeiro, Brasil, e calcular o risco de câncer associado a estas exposições. Foram realizados dois tipos de amostragem (fixa e móvel) adaptadas da metodologia nº 1.501 do Instituto Nacional de Segurança e Saúde Ocupacional (Estados Unidos), em seis postos de revenda de combustíveis na Zona Oeste da cidade. A amostragem fixa foi feita próxima às bombas de combustível, enquanto a móvel foi realizada através da coleta do ar na zona respiratória dos trabalhadores (frentistas), conforme estes se deslocavam pelo posto. As amostras foram analisadas por cromatografia gasosa com detecção por ionização em chama. Com os resultados das amostragens foram feitos os cálculos de risco à saúde, usando os indicadores Quociente de perigo (HQ) e Risco de câncer (CR), para avaliar os possíveis efeitos não-carcinogênicos e carcinogênicos, respectivamente, nos trabalhadores dos postos de revenda de combustíveis. As concentrações ambientais para a maioria dos compostos BTEX foram abaixo dos limites preconizados, menos para o benzeno, um composto carcinogênico, que apresentou concentrações muito acima dos limites, levando a altos valores de risco de câncer. Os resultados demonstraram que há riscos à saúde dos trabalhadores de postos de revenda de combustíveis, principalmente o risco de desenvolver câncer, devido à exposição excessiva ao benzeno.

La gasolina es una mezcla compleja de sustancias, entre ellas existen hidrocarburos como el benceno, tolueno, etilbenceno y xilenos (BTEX), emitiéndose estos compuestos a la atmósfera, donde se destaca el benceno, al tratarse de un carcinogénico comprobado. Los objetivos fueron evaluar las concentraciones de BTEX en el aire de puestos de reventa de combustibles, en el municipio de Río de Janeiro, Brasil, así como calcular el riesgo de cáncer asociado a estas exposiciones. Se realizaron dos tipos de muestra (fija y movible), adaptadas de la metodología nº 1.501 del Instituto Nacional de Seguridad y Salud Laboral (EE.UU.), en seis puestos de reventa de combustibles de la zona oeste de la ciudad. La muestra fija se realizó cerca de las bombas de combustible, mientras que la móvil se hizo mediante tomas de aire en la zona respiratoria de los trabajadores (de la gasolinera), a medida que estos se desplazaban por el lugar de trabajo. Las muestras se analizaron por cromatografía gaseosa con detección por ionización en llama. Junto a los resultados de las muestras, se realizaron cálculos de riesgo para la salud, usando los indicadores Cociente de peligro (HQ) y Riesgo de cáncer (CR), con el fin de evaluar los posibles efectos no-carcinogénicos y carcinogénicos, respectivamente, en los trabajadores de los puestos de reventa de combustibles. Las concentraciones ambientales para la mayoría de los compuestos BTEX estuvieron por debajo de los limites preconizados, menos en el caso del benceno, un compuesto carcinogénico, que presentó concentraciones muy por encima de los límites, llevando a altos valores de riesgo de cáncer. Los resultados demostraron que existen riesgos para la salud de los trabajadores de puestos de reventa de combustibles, principalmente, riesgo de desarrollar cáncer, debido a la exposición excesiva al benceno.

Adsorption of benzene and toluene from aqueous solution using a composite hydrogel of alginate-grafted with mesoporous silica.

Hydrogels are often claimed as optimal adsorbents for water treatment; however, their efficiency towards the removal of hydrophobic pollutants is still limited. As an alternative, hydrogels prepared from polymers functionalized with siliceous materials can overcome this issue. Here, a composite hydrogel (denoted as GEL-SBA15) was prepared using alginate grafted with mesoporous silica (SBA15) and poly(vinyl alcohol) for benzene and toluene adsorption from aqueous solutions. Adsorption studies demonstrated that a low dosage of GEL-SBA15 (10 mg) has a high adsorption capacity for benzene (1482.8 mg/g) and toluene (596.6 mg/g) under mild experimental conditions (pH 7.0, at 25 °C). Besides, the adsorption capacities of GEL-SBA15 for both pollutants were enhanced compared to the conventional hydrogel. Kinetic analysis showed that the adsorption of benzene and toluene follows a pseudo-second order model, while the experimental adsorption data were well-fitted by the Freundlich isotherm. According to this isotherm, the adsorption occurs via a collaborative process, and weak physical forces (π-π interactions, van der Waals and hydrophobic) are involved. Hence, the post-utilized GEL-SBA15 can be recycled and reused up to 6 times without losing adsorption performance. Although hydrogels are not common adsorbents for aromatic hydrocarbons, the results reported here rank GEL-SBA15 as a promising adsorbent for the removal of these pollutants from water.