Surveillance of Occupational Exposure to Volatile Organic Compounds at Gas Stations: A Scoping Review Protocol.

Health surveillance guides public policies, allows for the monitoring of occupational exposures that may cause health risks, and can prevent work-related diseases. The scoping review protocol herein is designed to map studies on the surveillance of occupational exposure to volatile organic compounds (VOCs) in gas stations and identify the governmental agencies and public health measures in different countries. This review protocol is based on the Joanna Briggs Institute manual and guided by the PRISMA Extension for Scoping Reviews. It includes research articles, theses, dissertations, and official documents on surveillance measures for occupational exposure to VOCs (i.e., benzene, ethylbenzene, toluene, and xylene) in gas stations from different countries. All languages and publication dates will be considered, and a spreadsheet will be used to extract and analyze qualitative and quantitative data. The final version will present the main surveillance measures implemented, responsible entities, results, challenges, limitations, and potential gaps in gas stations.

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.

Characterizations of highly efficient moderately halophilic toluene degrading exiguobacterium mexicanum M7 strain isolated from Egyptian saline sediments.

Toluene and other monoaromatic compounds are released into the environment particularly saline habitats due to the inappropriate disposal methods of petroleum products. Studying the bio-removal strategy is required to clean up these hazardous hydrocarbons that threaten all ecosystem life using halophilic bacteria with higher biodegradation efficiency of monoaromatic compounds as a sole carbon and energy source. Therefore, sixteen pure halophilic bacterial isolates were obtained from saline soil of Wadi An Natrun, Egypt, which have the ability to degrade toluene and consume it as the only source of carbon and energy. Amongst these isolates, isolate M7 exhibited the best growth with considerable properties. This isolate was selected as the most potent strain and identified based on phenotypic and genotypic characterizations. The strain M7 was belonging to Exiguobacterium genus and founded to be closely matched to the Exiguobacterium mexicanum with a similarity of 99%. Using toluene as sole carbon source, strain M7 showed good growth at a wide range temperature degree (20-40ºC), pH (5-9), and salt concentrations (2.5-10%, w/v) with optimal growth conditions at 35ºC, pH 8, and 5%, respectively. The biodegradation ratio of toluene was estimated at above optimal conditions and analyzed using Purge-Trap GC-MS. The results showed that strain M7 has the potentiality to degraded 88.32% of toluene within greatly short time (48 h). The current study findings support the potential ability to use strain M7 as a biotechnological tool in many applications such as effluent treatment and toluene waste management.

Exploring the substrate scope of glycerol dehydrogenase GldA from E. coli BW25113 towards cis-dihydrocatechol derivatives.

Glycerol dehydrogenase (GldA) from Escherichia coli BW25113, naturally catalyzes the oxidation of glycerol to dihydroxyacetone. It is known that GldA exhibits promiscuity towards short-chain C2-C4 alcohols. However, there are no reports regarding the substrate scope of GldA towards larger substrates. Herein we demonstrate that GldA can accept bulkier C6-C8 alcohols than previously anticipated. Overexpression of the gldA gene in the knockout background, E. coli BW25113 ΔgldA, was strikingly effective converting 2 mM of the compounds: cis-dihydrocatetechol, cis-(1 S,2 R)- 3-methylcyclohexa-3,5-diene-1,2-diol and cis-(1 S,2 R)- 3-ethylcyclohexa-3,5-diene-1,2-diol, into 2.04 ± 0.21 mM of catechol, 0.62 ± 0.11 mM 3-methylcatechol, and 0.16 ± 0.02 mM 3-ethylcatechol, respectively. In-silico studies on the active site of GldA enlightened the decrease in product formation as the steric substrate demand increased. These results are of high interests for E. coli-based cell factories expressing Rieske non-heme iron dioxygenases, producing cis-dihydrocatechols, since such sough-after valuable products can be immediately degraded by GldA, substantially hampering the expected performance of the recombinant platform.

Toluene exposure and changes in platelet count: a narrative review.

Toluene is a widely used solvent whose many toxic effects include neurological and hematological damage. This study reviewed evidence about the effects of toluene exposure on platelet count in humans. Three electronic databases and a digital library of theses and dissertations were searched using a specific strategy, yielding 64 articles, of which 14 were selected. These studies assessed a total of 15,759 participants, including 13,297 exposed individuals, mainly women exposed in an environmental setting. The major findings were: (1) conflicting results (positive, inverse, or no association), (2) cross-contamination with other substances, which impaired assessment of the relationship, and (3) a lack of studies. Thus, further research is needed on this topic, especially toluene exposure in isolation from associated substances.

O tolueno é um solvente amplamente utilizado com múltiplos efeitos tóxicos, sobretudo sobre o sistema nervoso central, assim como efeitos hematológicos. Este estudo foi conduzido para revisar a evidência presente na literatura sobre a exposição humana ao tolueno e seu efeito na contagem de plaquetas. Em 3 bases de dados eletrônicas e 1 biblioteca digital de teses e dissertações foram pesquisadas utilizando uma estratégia de busca específica, da qual resultaram 64 artigos, dos quais 14 foram selecionados. Estes avaliaram 15.759 pessoas, com 13.297 indivíduos expostos, compostos principalmente de mulheres em um cenário ambiental. Foram encontrados 3 grandes resultados, os quais incluem a presença de relações conflitantes (positiva, inversa, sem associação), a presença frequente de outras substâncias afetando a análise da relação, e a falta de estudos. Portanto, nós recomendamos mais pesquisas no tópico, com ênfase na exposição ao tolueno sem substâncias associadas.

Intranasal Methylprednisolone Ameliorates Neuroinflammation Induced by Chronic Toluene Exposure.

Inhalants are chemical substances that induce intoxication, and toluene is the main component of them. Increasing evidence indicates that a dependence on inhalants involves a state of chronic stress associated to the activation of immune cells in the central nervous system and release of proinflammatory mediators, especially in some brain areas such as the nucleus accumbens and frontal cortex, where the circuits of pleasure and reward are. In this study, anti-neuroinflammatory treatment based on a single dose of intranasal methylprednisolone was assessed in a murine model of chronic toluene exposure. The levels of proinflammatory mediators, expression levels of Iba-1 and GFAP, and histological changes in the frontal cortex and nucleus accumbens were evaluated after the treatment. The chronic exposure to toluene significantly increased the levels of TNF-α, IL-6, and NO, the expression of GFAP, and induced histological alterations in mouse brains. The treatment with intranasally administered MP significantly reduced the expression of TNF-α and NO and the expression of GFAP (p < 0.05); additionally, it reversed the central histological damage. These results indicate that intranasally administered methylprednisolone could be considered as a treatment to reverse neuroinflammation and histological damages associated with the use of inhalants.

Involuntary Emotional Expression Disorder in a Patient With Toluene Leukoencephalopathy / Trastorno de expresión emocional involuntaria en un paciente con leucoencefalopatía por tolueno

ABSTRACT Objective: Inhalant users may develop toluene leukoencephalopathy, a devastating neuropsychiatric disorder. We present a case of toluene-induced damage to the corticospinal and the corticonuclear tracts, which presented with involuntary emotional expression dis-order. Methods: Case study of a 20-year-old man with a 3-year history of frequent solvent abuse was admitted to the Neuropsychiatry Unit of the National Institute of Neurology and Neurosurgery because "he could not speak or walk" but would keep "laughing and crying without reason". Results: Neuropsychiatric examination revealed pathological laughter and crying, facial and speech apraxia, a bilateral pyramidal syndrome, and lack of control of urinary sphincter. Magnetic resonance imaging revealed a highly selective bilateral damage to the pyramidal system and the somatosensory pathway. SPECT imaging showed left fronto-parietal hypoperfusion. Conclusions: This document provides support for the understanding of involuntary emotional expression disorders as a differential diagnosis in the clinical practice of psychiatrists, as well as the functional anatomy of these conditions.

RESUMEN Objetivo: Los usuarios de inhalantes pueden contraer leucoencefalopatía por tolueno, un trastorno neuropsiquiátrico devastador. Se presenta un caso de daño inducido por tolueno en el tracto corticoespinal y corticonuclear, que se manifestó con un trastorno involuntario de la expresión emocional. Métodos: Un varón de 20 años con antecedente de 3 años de abuso de solventes ingresó en la Unidad de Neuropsiquiatría del Instituto Nacional de Neurología y Neurocirugía porque «no podía hablar ni caminar¼ y presentaba episodios súbitos de risa y llanto sin razón aparente. Resultados: La valoración neuropsiquiátrica reveló risa y llanto patológicos, apraxia facial y fonatoria, síndrome piramidal bilateral y ausencia de control del esfínter urinario. La resonancia magnética cerebral mostró un daño bilateral muy selectivo del sistema piramidal y la vía somatosensorial. La imagen de tomografía computarizada por emisión monofotónica mostró hipoperfusión frontoparietal izquierda. Conclusiones: Este documento proporciona apoyo para la comprensión de los trastornos de la expresión emocional involuntaria como diagnóstico diferencial en la práctica clínica de los psiquiatras, así como de la anatomía funcional de estas condiciones.

Neurotoxicidad en trabajadores petroquímicos con bajos índices de exposición a disolventes orgánicos / Neurotoxicity among petrochemical workers with low exposure indexes to organic solvents

Resumen: Objetivo: Estimar el desempeño neuropsicológico y su asociación con la exposición a disolventes orgánicos (DO) en trabajadores petroquímicos en México. Material y métodos: Estudio transversal en 203 trabajadores: 102 expuestos a DO y 101 no expuestos. Se evaluó el desempeño neuropsicológico con Neurobehavioral Core Test Battery y la exposición a DO con la medición de metabolitos de exposición para tolueno, xilenos y benceno. Resultados: Los trabajadores expuestos presentaron un peor desempeño en todas las pruebas (p<0.05), excepto en la prueba de Santa Ana. Esto se corroboró con modelos de regresión; los trabajadores expuestos a DO tuvieron un mayor número de errores y realizaron las pruebas en mayor tiempo (p<0.05), además de presentar mayores probabilidades de padecer síntomas de neurotoxicidad (OR: 2.93; IC95%: 0.96, 8.96). Conclusiones: La exposición ocupacional a disolventes orgánicos, aun a niveles permitidos por la normatividad mexicana vigente, se relacionó con un menor desempeño neuropsicológico.

Abstract: Objective: To estimate the neuropsychological performance and its association with exposure to organic solvents (OS) among petrochemical workers in Mexico. Materials and methods: Cross-sectional study including 203 workers: 102 exposed to OS and 101 non-exposed. Neuropsychological performance was evaluated with Neurobehavioral Core Test Battery. Exposure to OS was evaluated with the metabolites from exposure to toluene, xylenes and benzene. Results: Exposed workers presented with a worse performance in all tests (p<0.05), except for Santa Ana test. This was corroborated with regression models; workers exposed to OS had a higher number of mistakes and performed the tests in longer time (p<0.05), together with having greater odds of neurotoxicity symptoms (OR: 2.93; 95%CI: 0.96, 8.96). Conclusions: Occupational exposure to organic solvents, even at levels allowed by current Mexican standards, was related to an impaired neuropsychological performance.

Toluene: correlation between occupational exposure limits and biological exposure indices.

Threshold limit values for chemical substances and biological exposure indices are the main tools used in occupational hygiene and occupational medicine to control worker exposure levels. The correlation between these limits and indicators is of fundamental importance. The setting of new toluene exposure limits has raised discussion about which indicator to use. This article aims to enrich this debate with scientific data. Through a literature review, we provide a broad analysis of the factors that led to the lowering of the occupational exposure limit. Although internationally, biological indicators for toluene were replaced more than a decade ago, Brazilian authorities only began to discuss changing them in 2020. Toluene is a concern due to critical effects observed in exposed individuals, especially miscarriage. Urinary οrtho-cresol was suggested as the main biomarker in 2007. Given the broad data analysis, there are no doubts about the utility of οrtho-cresol as a biological indicator for toluene; what is lacking now is implementation of a monitoring system to comply with the legislation.

Os limites de exposição ocupacional às substâncias químicas e os indicadores biológicos de exposição são as principais ferramentas usadas pela Higiene Ocupacional e Medicina do Trabalho para o controle de exposições dos trabalhadores, e a correlação entre esses parâmetros é de fundamental importância. A adoção de novos limites de exposição ao tolueno abriu o debate sobre qual indicador usar, e este artigo tem como objetivo trazer dados científicos para essa discussão. Através de revisão bibliográfica, foi feita uma análise ampla dos fatores que levaram à redução do limite de exposição ocupacional. Embora, no cenário internacional, a substituição dos indicadores biológicos para o tolueno tenha acontecido há mais de uma década, somente no ano de 2020 as autoridades brasileiras trouxeram à tona essa discussão, com a alteração do indicador biológico de referência na Norma Regulamentadora n.º 7. A preocupação em torno do tolueno está baseada em seus efeitos críticos observados em indivíduos expostos, especialmente a indução de aborto espontâneo. Nesse sentido, já em 2007 foi sugerido o οrto-cresol urinário como principal biomarcador. Diante da ampla análise dos dados, não há dúvidas da representatividade do οrto-cresol como indicador biológico para o tolueno, restando agora a implementação de uma sistemática de monitorização para atender à legislação.

Enthalpic and Liquid-Phase Adsorption Study of Toluene-Cyclohexane and Toluene-Hexane Binary Systems on Modified Activated Carbons.

The liquid-phase adsorption of toluene in cyclohexane and hexane solutions on modified activated carbons was evaluated; the energy involved in the interaction between these solutions and the solids was determined by immersion enthalpies of pure solvents and their mixtures, and the contribution of the system constituents was calculated by differential enthalpies. The thermal treatment generated modifications that favored adsorption and interaction with the evaluated solutions, since it increased the textural parameters and the basic character of the samples. Cyclohexane could create greater competition with the adsorption sites compared to hexane, but it favored the increase in adsorption capacities (0.416 to 1.026 mmol g-1) and the interactions with the solid evaluated through the immersion enthalpies. The immersion enthalpies of pure solvents (-16.36 to -112.7 J g-1) and mixtures (-25.65 to -104.34 J g-1) had exothermic behaviors that were decreasing due to the possible displacement of solvent molecules when increasing the solute concentration in the mixtures. The differential enthalpies for toluene were negative (-18.63 to -2.14 J), mainly due to the π-π interaction with the solid, while those of the solvent-solid component tended to be positive values (-4.25 to 55.97 J) due to the displacement of the solvent molecules by those of toluene.

Black Fungi and Hydrocarbons: An Environmental Survey for Alkylbenzene Assimilation.

Environmental pollution with alkylbenzene hydrocarbons such as toluene is a recurring phenomenon. Their toxicity and harmful effect on people and the environment drive the search for sustainable removal techniques such as bioremediation, which is based on the microbial metabolism of xenobiotic compounds. Melanized fungi present extremophilic characteristics, which allow their survival in inhospitable habitats such as those contaminated with hydrocarbons. Screening methodologies for testing the microbial assimilation of volatile organic compounds (VOC) are scarce despite their importance for the bioremediation of hydrocarbon associated areas. In this study, 200 strains of melanized fungi were isolated from four different hydrocarbon-related environments by using selective methods, and their biodiversity was assessed by molecular and ecological analyses. Seventeen genera and 27 species from three main orders, namely Chaetothyriales, Cladosporiales, and Pleosporales, were identified. The ecological analysis showed a particular species distribution according to their original substrate. The isolated strains were also screened for their toluene assimilation potential using a simple and inexpensive methodology based on miniaturized incubations under controlled atmospheres. The biomass produced by the 200 strains with toluene as the sole carbon source was compared against positive and negative controls, with glucose and with only mineral medium, respectively. Nineteen strains were selected as the most promising for further investigation on the biodegradation of alkylbenzenes.

Passive sampling of toluene (and benzene) in indoor air using a semipermeable membrane device.

The distribution and concentration of organic compounds in the environment have attracted great interest mainly due to their capability of bioaccumulation, dispersion, and danger to living organisms. Factors such as urbanization, population growth, and the emergence of new technologies contribute to the increase in pollutant emissions, especially volatile organic compounds (VOCs), such as benzene, toluene, ethylbenzene, and xylenes (BTEX). These compounds are emitted by several sources, becoming more common in work environments, influencing indoor air quality (IAQ), which can cause health damage, in addition to increasing the likelihood of cancer development. In this context, we developed a semipermeable membrane device (SPMD), consisting of low density polyethylene membrane (8 cm long × 3 cm wide), filled with 3 mL of acetonitrile, for passive sampling of toluene (and benzene) in gas phase. With this configuration, the SPMD needed 24 h exposure to the indoor air in order to achieve equilibrium. The target compounds were quantified in the acceptor phase by HPLC-DAD. The optimized SPMD was tested for the collection of toluene and benzene in six chemistry laboratories at Fluminense Federal University and in five nail salons in the city of Niterói, in the state of Rio de Janeiro, Brazil. The developed sampling method was able to identify the analytes in the indoor air of the studied environments, and was easy to operate, with no need to clean up the extracts, allowing their direct injection into the chromatographic system.

Intoxicación por tolueno / Toluene poisoning

Resumen El ser humano está inmerso en un entorno donde inhala, ingiere o absorbe muchas sustancias químicas, de las cuales toman relevancia las exposiciones en los lugares de trabajo y las que causan la muerte en la práctica médico forense. El tolueno es un inhibidor neuronal asociado con daño progresivo del sistema nervioso central y periférico, su toxicidad puede ocurrir por inhalación involuntaria o deliberada y puede llevar incluso a la muerte. Se realizó una revisión bibliográfica en diferentes bases de datos, de los artículos publicados referentes al tema de los últimos ocho años, con el objetivo de revisar las características del químico, el metabolismo, las intoxicaciones agudas y las crónicas, así como sus implicaciones letales. Se concluye que para mejorar la pericia médico legal, al valorar casos de intoxicacion por tolueno se deben de contemplar los criterios de causalidad en los casos de enfermedad laboral y en sospecha de causa de muerte es fundamentantal el resultado toxicológico ante la ausencia de hallazgos específicos en la autopsia.

Abstract The human being is immersed in an environment where he inhales, ingests or absorbs many chemical substances, in forensic medical practice the exposures in the workplace and those that cause death take on relevance. Toluene is a neuronal inhibitor associated with progressive damage of the central and peripheral nervous system, its toxicity can occur by involuntary or deliberate inhalation and can even lead to death. A bibliographic review was carried out in different databases, of the published articles referring to the subject of the last eight years, with the objective of reviewing the characteristics of the chemical, the metabolism, both acute and chronic poisoning and its lethal implications. It is concluded that to improve the legal medical expertise when assessing cases of toluene poisoning, causality criteria must be considered in cases of occupational disease and in suspected cases of death the toxicology result is fundamental in the absence of specific findings in the autopsy.

Biomarkers of susceptibility and effect in car painters exposed to organic solvents.

INTRODUCTION: Car painters are routinely exposed to organic solvents classified as carcinogenic and mutagenic substances. OBJECTIVE: To characterize the population susceptibility and evaluate the genotoxic effects of exposure to organic solvents. METHODS: A cross-sectional study comparing a group of car painters exposed to organic solvents with a non-exposed group. CYP2E1 polymorphisms and the presence of micronuclei in lymphocytes were determined. RESULTS: One hundred twenty-two workers participated in the study: 62 who worked in car paint shops and were exposed to solvents, and 60 who were not exposed. There were statistically significant differences between the two groups regarding micronucleated cells and nucleoplasmic bridges frequencies (p= 0.042 and p= 0.046, respectively; exact likelihood ratio). Significant differences were found at the interaction between the CYP2E1 genotype c1c1 and occupational exposure to solvents, with higher frequencies of micronuclei (p= 0.013) and micronucleated cells (p= 0.015). However, when the frequencies of micronuclei, micronucleated cells and nucleoplasmic bridges in the exposure group were compared between the c1c1 and c2c2/c1c2 allele groups of the CYP2E1 polymorphism, statistically significant differences were found. CONCLUSIONS: This study confirms that when workers with CYP2E1 polymorphisms, specifically the c1c1 genotype, are exposed to organic solvents, they are more likely to have somatic cell mutations, a condition associated with increased susceptibility to diseases such as cancer.

INTRODUCCIÓN: Los pintores de vehículos automotores están rutinariamente expuestos a agentes como los solventes orgánicos, capaces de producir efectos mutágenos y carcinógenos. OBJETIVO: Caracterizar la susceptibilidad poblacional y evaluar los efectos genotóxicos debidos a la exposición a solventes orgánicos. MÉTODOS: Estudio de corte transversal que comparó a un grupo de pintores de carros expuestos a solventes orgánicos con un grupo de personas no expuestas. Fueron determinados tanto los polimorfismos de CYP2E1 como la presencia de micronúcleos en linfocitos. RESULTADOS: Participaron 122 personas, 62 trabajadores de talleres de pintura de autos expuestos a solventes y 60 personas no expuestas. Con relación al cuestionario Q 16, 32% de los expuestos refirieron síntomas sugestivos de neurotoxicidad. Las frecuencias de células micronucleadas y de puentes nucleoplásmicos fueron significativamente mayores en los expuestos que en los no expuestos: p= 0.042 y p= 0.046, respectivamente, Razón de verosimilitud exacta). Fueron halladas diferencias significativas en la interacción de CYP2E1 (c1c1) y la exposición ocupacional a solventes, con mayores frecuencias de micronúcleos (p= 0.013) y de células micronucleadas (p= 0.015). CONCLUSIONES: Este estudio reafirma que los trabajadores expuestos a solventes orgánicos con polimorfismos de CYP2E1, específicamente con genotipo c1c1, tienen mayor probabilidad de presentar mutaciones en las células somáticas, condición asociada con una mayor susceptibilidad a enfermedades como el cáncer.

Toxicity of a mixture of monoaromatic hydrocarbons (BTX) to a tropical marine microcrustacean.

This study evaluated the toxicity of benzene, toluene, and xylenes (BTX), isolated and in binary mixtures to Mysidopsis juniae. The organisms were exposed to BTX, and combined effect patterns were predicted by applying the theoretical models of Concentration Addition and Independent Action. According to the LC50 of the isolated compounds, xylene (16.1 ± 2.4 mg L-1) was considered the most toxic, followed by toluene (38.0 ± 5.3 mg L-1) and, lastly, benzene (78.0 ± 2.9 mg L-1). The binary combinations showed deviations from additivity, with exposure to the xylene-benzene mixture presenting as antagonistic, while the xylene-toluene and toluene-benzene mixtures were better explained by a dose ratio deviation, with toluene being responsible for the antagonistic pattern. This study provides new insights into toxicity prediction of a BTX mixture, which adds value to the risk assessment procedure over evaluation of chemical hazards on a case-by-case basis.

Evaluation of bioaerosols by flow cytometry and removal performance in a biofilter treating toluene/ethyl acetate vapors.

The removal efficiency (RE) and bioaerosol emission of a perlite biofilter treating vapors of toluene (T) and/or ethyl acetate (EA) were assessed, under different operating conditions, during 171 days. Under the first stages of operation, a mixture of EA and T was treated, with equivalent inlet loads (ILs) of each compound (ranging from 26 to 84 g m-3 h-1), achieving a 100% RE of EA, and a maximum elimination capacity (EC) of T of 58.7 g m-3 h-1. An inhibition of T removal was noted in presence of EA, as T was treated subsequently to EA, along biofilter depth. A 17 days starvation period induced no global deterioration of performance regarding EA removal, but a 50% lower RE of T. Suspension of one contaminant, with interspersed feeding of only one component of the mixture, caused a permanent drop of the RE of EA (to 87.3%), after a T only feeding of 41 days. Flow cytometry (FC) was applied for quantification of bioaerosols, allowing for differentiation between viable, dead and damaged cells. During the overall biofilter operation, bioaerosol emission was not statistically different from bioaerosol retention. However, the biofilter significantly emitted bioaerosols (mostly viable cells) during start-up and IL increase, whereas a global retention of dead cells was observed during the interspersed feeding of one contaminant. Bioaerosols measured by FC (107 Cells m-3) were three orders of magnitude greater than with plate counting dishes, indicating that FC does not underestimate bioaerosols as culture dependent techniques.

Biomarkers of susceptibility and effect in car painters exposed to organic solvents / Biomarcadores de susceptibilidad y efecto en pintores de carros expuestos a solventes orgánicos

Abstract Introduction: Car painters are routinely exposed to organic solvents classified as carcinogenic and mutagenic substances. Objective: To characterize the population susceptibility and evaluate the genotoxic effects of exposure to organic solvents. Methods: A cross-sectional study comparing a group of car painters exposed to organic solvents with a non-exposed group. CYP2E1 polymorphisms and the presence of micronuclei in lymphocytes were determined. Results: One hundred twenty-two workers participated in the study: 62 who worked in car paint shops and were exposed to solvents, and 60 who were not exposed. There were statistically significant differences between the two groups regarding micronucleated cells and nucleoplasmic bridges frequencies (p=0.042 and p=0.046, respectively; exact likelihood ratio). Significant differences were found at the interaction between the CYP2E1 genotype c1c1 and occupational exposure to solvents, with higher frequencies of micronuclei (p= 0.013) and micronucleated cells (p= 0.015). However, when the frequencies of micronuclei, micronucleated cells and nucleoplasmic bridges in the exposure group were compared between the c1c1 and c2c2/c1c2 allele groups of the CYP2E1 polymorphism, statistically significant differences were found. Conclusions: This study confirms that when workers with CYP2E1 polymorphisms, specifically the c1c1 genotype, are exposed to organic solvents, they are more likely to have somatic cell mutations, a condition associated with increased susceptibility to diseases such as cancer

Resumen Introducción: Los pintores de vehículos automotores están rutinariamente expuestos a agentes como los solventes orgánicos, capaces de producir efectos mutágenos y carcinógenos. Objetivo: Caracterizar la susceptibilidad poblacional y evaluar los efectos genotóxicos debidos a la exposición a solventes orgánicos. Métodos: Estudio de corte transversal que comparó a un grupo de pintores de carros expuestos a solven tes orgánicos con un grupo de personas no expuestas. Fueron determinados tanto los polimorfismos de CYP2E1 como la presencia de micronúcleos en linfocitos. Resultados: Participaron 122 personas, 62 trabajadores de talleres de pintura de autos expuestos a solventes y 60 personas no expuestas. Con relación al cuestionario Q 16, 32% de los expuestos refirieron síntomas sugestivos de neurotoxicidad. Las frecuencias de células micronucleadas y de puentes nucleoplásmicos fueron significativamente mayores en los expuestos que en los no expuestos: p= 0.042 y p= 0.046, respectivamente, Razón de verosimilitud exacta). Fueron halladas diferencias significativas en la interacción de CYP2E1 (c1c1) y la exposición ocupacional a solventes, con mayores frecuencias de micronúcleos (p= 0.013) y de células micronucleadas (p= 0.015). Conclusiones: Este estudio reafirma que los trabajadores expuestos a solventes orgánicos con polimorfismos de CYP2E1, específicamente con genotipo c1c1, tienen mayor probabilidad de presentar mutaciones en las células somáticas, condición asociada con una mayor susceptibilidad a enfermedades como el cáncer

Public health issues from crude-oil production in the Ecuadorian Amazon territories.

Crude oil production (COP) is a high-pollution industry but the vast Amazon rainforest has been an active COP zone for South America. Although COP has been associated with a variety of health effects among workers around the world, such effects have not been adequately investigated in the Amazon region, especially at the community level. Therefore, this review was conducted to provide a report about COP in the Amazon of Ecuador and about its association with health status of indigenous human populations. Some epidemiological surveys in the Amazonian Territories indicate that COP has been associated with health problems in the surrounding populations, e.g. cancers in the stomach, rectum, skin, soft tissue, kidney and cervix in adults, and leukemia in children. In addition, some biomarkers and mechanistic studies show exposure effects. However, due to limitations from these studies, contradictory associations have been reported. Our review indicates that COP in the Amazonian territories of northern Ecuador was characterised by contamination which could have affected the indigenous and non-indigenous populations. However, there have not been dedicated investigations to provide relationships between the contamination and the subsequent exposure-health effects. Since indigenous populations have different lifestyle and cultures from regular city dwellers, systematic studies on their potential health hazards need to be conducted. Due to the remote locations and sparse populations, these new studies may involve the use of novel and genomic-based biomarkers as well as using high technology in the remote regions.

Diverse sleep patterns, psychiatric disorders, and perceived stress in inhalants users living on the streets of Mexico City.

Homeless people face stressful circumstances influencing drug consumption, mental health, and sleep disorders. We performed an interdisciplinary study involving psychometric, polysomnographic, and ethnographic records to relate stress, psychiatric disorders, drug consumption, and sleep in ten people (four women, M = 32 y/o) living on the streets of Mexico City. Toluene-based inhalant dependence and suicidality were the more common psychiatric disorders among participants. They also presented sleep fragmentation; some manifested insomnia or sleep restriction, whereas others displayed extended rapid-eye movement sleep latencies associated with depression or inhalant consumption. Inhalants are used to improve mood, strengthen social bonds, and induce either sleep or alertness during the night. Inter-individual distinctions may be related to differential levels of intoxication, stress perception, backgrounds, and abilities to live and sleep on the street. Sleep restriction seems to be the more common factor, which may enhance the negative consequences of street situation.

Evaluation of immunological, inflammatory, and oxidative stress biomarkers in gasoline station attendants.

BACKGROUND: Gasoline is a complex mixture of saturated and unsaturated hydrocarbons, in which aromatic compounds, such as BTX (benzene, toluene, and xylene) feature as the main constituents. Simultaneous exposure to these aromatic hydrocarbons causes a significant impact on benzene toxicity. In order to detect early alterations caused in gasoline station attendants exposed to BTX compounds, immunological, inflammatory, and oxidative stress biomarkers were evaluated. METHODS: A total of 66 male subjects participated in this study. The gasoline station attendants (GSA) group consisted of 38 gasoline station attendants from Rio Grande do Sul, Brazil. The non-exposed group consisted of 28 subjects who were non-smokers and who had no history of occupational exposure. Environmental and biological monitoring of BTX exposure was performed using blood and urine. RESULTS: The GSA group showed increased BTX concentrations in relation to the non-exposed group (p < 0.001). The GSA group showed elevated protein carbonyl (PCO) levels and pro-inflammatory cytokines, decreased expression of CD80 and CD86 in monocytes, and reduced glutathione S-transferase (GST) activity compared to the non-exposed group (p < 0.05). BTX levels and trans,trans-muconic acid levels were positively correlated with pro-inflammatory cytokines and negatively correlated with interleukin-10 contents (p < 0.001). Increased levels of pro-inflammatory cytokines were accompanied by increased PCO contents and decreased GST activity (p < 0.001). Furthermore, according to the multiple linear regression analysis, benzene exposure was the only factor that significantly contributed to the increased pro-inflammatory cytokines (p < 0.05). CONCLUSIONS: Taken together, these findings show the influence of exposure to BTX compounds, especially benzene, on the immunological, inflammatory, and oxidative stress biomarkers evaluated. Furthermore, the data suggest the relationship among the evaluated biomarkers of effect, which could contribute to providing early signs of damage to biomolecules in subjects occupationally exposed to BTX compounds.