Sulfate supply decreases barium availability, uptake, and toxicity in lettuce plants grown in a tropical Ba-contaminated soil.

Barium (Ba) is a non-essential element that can cause toxicity in living organisms and environmental contamination. Plants absorb barium predominantly in its divalent cationic form Ba2+. Sulfur (S) can decrease the availability of Ba2+ in the soil by causing its precipitation as barium sulfate, a compound known for its very low solubility. The objective of this study was to evaluate the effect of soil sulfate supply in soil Ba fractions, as well as on plant growth, and Ba and S uptake by lettuce plants grown in artificially Ba-contaminated soil under greenhouse conditions. The treatments consisted of five Ba doses (0, 150, 300, 450, and 600 mg kg-1 Ba, as barium chloride) combined with three S doses (0, 40, and 80 mg kg-1 S, as potassium sulfate). The treatments were applied to soil samples (2.5 kg) and placed in plastic pots for plant cultivation. The Ba fractions analyzed were extractable-Ba, organic matter-Ba, oxides associated-Ba, and residual-Ba. The results indicate that the extractable-Ba fraction was the main one responsible for Ba bioavailability and phytotoxicity, probably corresponding to the exchangeable Ba in the soil. The dose of 80 mg kg-1 of S reduced extractable-Ba by 30% at higher Ba doses while it increased the other fractions. Furthermore, S supply attenuated the growth inhibition in plants under Ba exposure. Thus, S supply protected the lettuce plants from Ba toxicity by reduction of Ba availability in soil and plant growth enhancement. The results suggest that sulfate supply is a suitable strategy for managing Ba-contaminated areas.

Marine Submicron Aerosols from the Gulf of Mexico: Polluted and Acidic with Rapid Production of Sulfate and Organosulfates.

We measured submicron aerosols (PM1) at a beachfront site in Texas in Spring 2021 to characterize the "background" aerosol chemical composition advecting into Texas and the factors controlling this composition. Observations show that marine "background" aerosols from the Gulf of Mexico were highly processed and acidic; sulfate was the most abundant component (on average 57% of total PM1 mass), followed by organic material (26%). These chemical characteristics are similar to those observed at other marine locations globally. However, Gulf "background" aerosols were much more polluted; the average non-refractory (NR-) PM1 mass concentration was 3-70 times higher than that observed in other clean marine atmospheres. Anthropogenic shipping emissions over the Gulf of Mexico explain 78.3% of the total measured "background" sulfate in the Gulf air. We frequently observed haze pollution in the air mass from the Gulf, with significantly elevated concentrations of sulfate, organosulfates, and secondary organic aerosol associated with sulfuric acid. Analysis suggests that aqueous oxidation of shipping emissions over the Gulf of Mexico by peroxides in the particles might potentially be an important pathway for the rapid production of acidic sulfate and organosulfates during the haze episodes under acidic conditions.

Two problems in one shot: Vinasse and glycerol co-digestion in a thermophilic high-rate reactor to improve process stability even at high sulfate concentrations.

Anaerobic co-digestion (AcoD) of sugarcane vinasse and glycerol can be profitable because of the destination of two biofuel wastes produced in large quantities in Brazil (ethanol and biodiesel, respectively) and the complementary properties of these substrates. Thus, the objective of this study was to assess the effect of increasing the organic loading rate (OLR) from 2 to 20 kg COD m-3 d-1 on the AcoD of vinasse and glycerol (50 %:50 % on a COD basis) in a thermophilic (55 °C) anaerobic fluidized bed reactor (AFBR). The highest methane production rate was observed at 20 kg COD m-3 d-1 (8.83 L CH4 d-1 L-1), while the methane yield remained stable at around 265 NmL CH4 g-1 CODrem in all conditions, even when influent vinasse reached 1811 mg SO42- L-1 (10 kg COD m-3 d-1). Sulfate was not detected in the effluent. Bacterial genera related to sulfate removal, such as Desulfovibrio and Desulfomicrobium, were observed by means of shotgun metagenomic sequencing at 10 kg COD m-3 d-1, as well as the acetoclastic archaea Methanosaeta and prevalence of genes encoding enzymes related to acetoclastic methanogenesis. It was concluded that process efficiency and methane production occurred even in higher sulfate concentrations due to glycerol addition.

Role of sulfated polysaccharides from seaweeds in bone regeneration: A systematic review.

Studies on the effect of sulfated polysaccharides from seaweed on bone regeneration have increased in recent years. However, there is no consensus on how to use them and their real effectiveness in that process. Thereby, we carried out a systematic review to answer the question "Do the sulfated polysaccharides from seaweeds promote osteogenesis?". Searches were performed in Pubmed, Scopus, and Web of Knowledge databases. A total of 599 articles were selected, resulting in 14 eligible studies. Results showed that the sulfated polysaccharides from seaweeds increase the osteogenic markers evaluated. Nevertheless, due to the lack of standardization on protocols used, the results should be cautiously interpreted. In addition, studies using animal models are still scarce, and the results with cellular models cannot always be extrapolated to systems that are more complex. Despite the study limitations, the use of sulfated polysaccharides appears to promote in vitro osteogenesis and enhance bone regeneration.

Basic oxygen furnace sludge to treat industrial arsenic- and sulfate-rich acid mine drainage.

In this study, four systems (S1, S2, S3, and S4) were evaluated to determine whether basic oxygen furnace sludge (BOFS), mainly composed of Fe (84%, mostly as elemental Fe and FeO), Ca (3%, as CaCO3), and Si (1%), is capable of removing As-spiked, Mn, Mg, and sulfate from an industrial acid mine drainage (AMDi) collected in a gold mine in Minas Gerais, Brazil. In the S1 system (BOFS/deionized water pH 2.5), the stability of the residue was evaluated for 408 h under agitation. The results showed that only Ca and Mg were solubilized, and the pH increased from 2.5 up to 11.4 within the initial 24 h and kept still until the end of the experiment (408 h). The S2 system (BOFS/AMDi) achieved 100% removal of As and Mn, and 70% removal of sulfate after 648 h. In the first 30 min, the pH increased from 2.5 to 10, which was maintained until the end of the experiment. The removal of As, Mn, and sulfate in the presence of hydrogen peroxide (S3 and S4 systems - BOFS/AMDi/H2O2) was similar to that in the S2 system, which contained only BOFS. The formation of iron oxides was not accelerated by H2O2. As regards the removal of arsenic and sulfate species, the formation of incipient calcium arsenate and calcium sulfate dehydrated was indicated by X-ray diffraction analysis and PHREEQC modeling. Dissolved manganese and magnesium precipitated as oxides, according to the geochemical modeling. After contact with AMDi, the raw BOFS, initially classified as hazardous waste, became a non-inert waste, which implies simplified, less costly disposal. Except for sulfate, the concentrations of all the other elements were below the maximum permitted levels.

Role of sulfate, chloride, and nitrate anions on the degradation of fluoroquinolone antibiotics by photoelectro-Fenton.

Taking ciprofloxacin (CIP) as a fluoroquinolone antibiotic model, this work explores the role of common anions (sulfate, nitrate, and chloride) during the application of photoelectro-Fenton (PEF) at natural pH to degrade this type of compound in water. The system was composed of an IrO2 anode, Ti, or gas diffusion electrode (GDE) as cathode, Fe2+, and UV (254 nm). To determine the implications of these anions, the degradation pathway and efficiency of the PEF sub-processes (UV photolysis, anodic oxidation, and electro-Fenton at natural pH) were studied in the individual presence of the anions. The results highlight that degradation routes and kinetics are strongly dependent on electrolytes. When chloride and nitrate ions were present, indirect electro-chemical oxidation was identified by electro-generated HOCl and nitrogenated oxidative species, respectively. Additionally, direct photolysis and direct oxidation at the anode surface were identified as degradation routes. As a consequence of the different pathways, six primary CIP by-products were identified. Therefore, a scheme was proposed representing the pathways involved in the degradation of CIP when submitted to PEF in water with chloride, nitrate, and sulfate ions, showing the complexity of this process. Promoted by individual and synergistic actions of this process, the PEF system leads to a complete elimination of CIP with total removal of antibiotic activity against Staphylococcus aureus and Escherichia coli, and significant mineralization. Finally, the role of the anions was tested in seawater containing CIP, in which the positive contributions of the anions were partially suppressed by its OH radical scavenger action. The findings are of interest for the understanding of the degradation of antibiotics via the PEF process in different matrices containing sulfate, nitrate, and chloride ions.

Unravelling the molecular structure and packing of a planar molecule by combining nuclear magnetic resonance and scanning tunneling microscopy.

The determination of the molecular structure of a porphyrin is achieved by using nuclear magnetic resonance (NMR) and scanning tunneling microscopy (STM) techniques. Since macroscopic crystals cannot be obtained in this system, this combination of techniques is crucial to solve the molecular structure without the need for X-ray crystallography. For this purpose, previous knowledge of the flatness of the reagent molecules (a porphyrin and its functionalizing group, a naphthalimide) and the resulting molecular structure obtained by a force-field simulation are used. The exponents of the I-V curves obtained by scanning tunneling spectroscopy (STS) allow us to check whether the thickness of the film of molecules is greater than a monolayer, even when there is no direct access to the exposed surface of the metal substrate. Photoluminescence (PL), optical absorption, infrared (IR) reflectance and solubility tests are used to confirm the results obtained here with this NMR/STM/STS combination.

Effect of gas and kerosene space heaters on indoor air quality: a study in homes of Santiago, Chile.

The impact of outdoor and indoor pollution sources on indoor air quality in Santiago, Chile was investigated. Toward this end, 16 homes were sampled in four sessions. Each session included an outdoor site and four homes using different unvented space heaters (electric or central heating, compressed natural gas, liquefied petroleum gas, and kerosene). Average outdoor fine particulate matter (PM2.5) concentrations were very high (55.9 microg x m(-3)), and a large fraction of these particles penetrated indoors. PM2.5 and several PM2.5 components (including sulfate, elemental carbon, organic carbon, metals, and polycyclic aromatic hydrocarbons) were elevated in homes using kerosene heaters. Nitrogen dioxide (NO2) and ultrafine particles (UFPs) were higher in homes with combustion heaters as compared with those with electric heaters or central heating. A regression model was used to assess the effect of heater use on continuous indoor PM2.5 concentrations when windows were closed. The model found an impact only for kerosene heaters (45.8 microg m(-3)).

Experimental and theoretical characterization of molecular complexes formed between OCS and XY molecules (X, Y = F, Cl and Br) and their role in photochemical matrix reactions.

Molecular complexes between OCS and ClF, Cl(2), Br(2), or BrCl have for the first time been isolated in solid matrixes at low temperature, and characterized by their IR spectra. 1 : 1 adducts between OCS and ClF, Cl(2), or BrCl were formed by broad-band UV-visible photolysis of matrix-isolated FC(O)SCl, ClC(O)SCl or BrC(O)SCl, respectively. Co-deposition of gaseous mixtures of OCS and ClF or Br(2) diluted with Ar on a CsI window cooled to approximately 15 K led to the identification of 1 : 1 complexes, while similar mixtures of OCS and Cl(2) gave rise mainly to 1 : 2 species. The differences in the structures and stoichiometries of the molecular complexes may well be responsible for the different reaction channels observed for the photochemical matrix reactions between OCS and Cl(2) or Br(2). The structures, energy differences, vibrational spectra, and bonding properties of all the possible complexes formed between OCS and XY (XY = ClF, Cl(2), Br(2), or BrCl) have been studied with different theoretical approximations.

Air emissions assessment from offshore oil activities in Sonda de Campeche, Mexico.

Air emission data from offshore oil platforms, gas and oil processing installations and contribution of marine activities at the Sonda de Campeche, located at the Gulf of Mexico, were compiled and integrated to facilitate the study of long range transport of pollutants into the region. From this important region, roughly 76% of the total Mexican oil and gas production is obtained. It was estimated that the total air emissions of all contaminants are approximately 821,000 tons per year. Hydrocarbons are the largest pollutant emissions with 277,590 tons per year, generated during flaring activities, and SOx in second place with 185,907 tons per year. Marine and aviation activities contribute with less than 2% of total emissions. Mass of pollutants emitted per barrel of petroleum produced calculated in this work, are in the range reported by similar oil companies.

Occupational exposures to acid mists and gases and ulcerative lesions of the oral mucosa.

BACKGROUND: This study examines the hypothesis that acid mist or mixtures of acid mists and acid gases are associated with ulcerative lesions of the oral mucosa. METHODS: All 665 active male workers of a metal processing factory were the study population. Semi-quantitative measures of exposure were estimated from a job exposure matrix constructed with industrial hygienist scoring and job titles. Ulcerative lesions of the oral mucosa were identified with standardized clinical dental exams. RESULTS: Past exposure to acid mists were positively associated with ulcerative lesions of the oral mucosa but only among workers without lip sealing (age- and alcohol consumption-adjusted prevalence ratio (PR), PR(adjusted) = 3.40; 90% CI: 1.48-7.85). Also in this worker group, the mixture of acid mists and acid gases was associated with ulcerative lesions of the oral mucosa limited to exposure in the past (PR(adjusted) = 2.83; 90% CI: 1.12-7.17). CONCLUSIONS: There is a positive association between acid mist or mixtures of acid mists and acid gases and ulcerative lesions of the oral mucosa only in the absence of lip sealing. The evidence of a chronic rather than acute irritative process suggests a possible step on the etiology of oral malignancies, which needs investigation.

Air Quality monitoring in the city of Córdoba (Argentina)

Se midieron las concentraciones de óxidos de nitrógeno y azufre, monóxido de carbono y otras sustancias volátiles en distintas localidades de la ciudad de Córdoba, Argentina, desde junio de 1995

Manual de tecnologías de medición de concentraciones de gases y material particulado en chimeneas y atmósfera

Presenta información sobre la contaminación del aire por parte de las industrias. En primer lugar brinda las características más importantes de los contaminantes del aire y sus efectos sobre el ambiente, y su propagación. Luego brinda normas de calidad ambiental, y luego la mayor parte de la obra trata sobre los métodos de medición, análisis e instrumentación para los distintos tipos de contaminantes, como ozono, hidrocarburos, oxidos de azufre y nitrógeno, plomo, ácido sulfúrico, etc

Air Quality monitoring in the city of Córdoba (Argentina)

Se midieron las concentraciones de óxidos de nitrógeno y azufre, monóxido de carbono y otras sustancias volátiles en distintas localidades de la ciudad de Córdoba, Argentina, desde junio de 1995

Manual de tecnologías de medición de concentraciones de gases y material particulado en chimeneas y atmósfera

Presenta información sobre la contaminación del aire por parte de las industrias. En primer lugar brinda las características más importantes de los contaminantes del aire y sus efectos sobre el ambiente, y su propagación. Luego brinda normas de calidad ambiental, y luego la mayor parte de la obra trata sobre los métodos de medición, análisis e instrumentación para los distintos tipos de contaminantes, como ozono, hidrocarburos, oxidos de azufre y nitrógeno, plomo, ácido sulfúrico, etc

Manual de tecnologías de medición de concentraciones de gases y material particulado en chimeneas y atmósfera

Presenta información sobre la contaminación del aire por parte de las industrias. En primer lugar brinda las características más importantes de los contaminantes del aire y sus efectos sobre el ambiente, y su propagación. Luego brinda normas de calidad ambiental, y luego la mayor parte de la obra trata sobre los métodos de medición, análisis e instrumentación para los distintos tipos de contaminantes, como ozono, hidrocarburos, oxidos de azufre y nitrógeno, plomo, ácido sulfúrico, etc

Impact winter and the Cretaceous/Tertiary extinctions: results of a Chicxulub asteroid impact model.

The Chicxulub impact crater in Mexico is the site of the impact purported to have caused mass extinctions at the Cretaceous/Tertiary (K/T) boundary. 2-D hydrocode modeling of the impact, coupled with studies of the impact site geology, indicate that between 0.4 and 7.0 x 10(17) g of sulfur were vaporized by the impact into anhydrite target rocks. A small portion of the sulfur was released as SO3 or SO4, which converted rapidly into H2SO4 aerosol and fell as acid rain. A radiative transfer model, coupled with a model of coagulation indicates that the aerosol prolonged the initial blackout period caused by impact dust only if the aerosol contained impurities. A larger portion of sulfur was released as SO2, which converted to aerosol slowly, due to the rate-limiting oxidation of SO2. Our radiative transfer calculations, combined with rates of acid production, coagulation, and diffusion indicate that solar transmission was reduced to 10-20% of normal for a period of 8-13 yr. This reduction produced a climate forcing (cooling) of -300 Wm-2, which far exceeded the +8 Wm-2 greenhouse warming, caused by the CO2 released through the vaporization of carbonates, and therefore produced a decade of freezing and near-freezing temperatures. Several decades of moderate warming followed the decade of severe cooling due to the long residence time of CO2. The prolonged impact winter may have been a major cause of the K/T extinctions.

Ecología y salud / Ecology and health

Este trabajo de investigación participativo se ha dividido en 5 temas, los cuales nos dan un enfoque general de la situación ecológica y de salud en la que se desenvuelve nuestro medio en relación de la posibilidad de que el futuro se de un cambio en el cual el hombre se reconcilie con la naturaleza y no siga infringiendo daños en ella. En el primer capítulo tenemos concepción occidental de ciencia, ecología y salud. El capítulo segundo se trata de el desarrollo de la destrucción del medio ambiente, presentando la contaminación que se produce dentro de los hospitales. El tercer capítulo abarca los daños ecológicos producto de la deforestación realizada por las industrias madederas. El cuarto capítulo va dirigido a determinar que instituciones se preocupan por este fenómeno y que programas preventivos han desarrollado. El quinto capítulo hace una relación entre Educación, Ecología y salud, en donde damos a conocer que es lo que se enseña desde el nivel pre-primario hasta el universitario

Urban air pollution in Latin America and the Caribbean: health perspectives.

In the last few years, air pollution has become a major issue in some countries of Latin America and the Caribbean because of urban development and growing industrialization. In addition to industrial processes often concentrated in the cities, vehicle emission and stationary-source fuel combustion are the primary sources of air pollution. Although air-quality standards have been established in some Latin American countries, these are frequently exceeded. Adverse health effects of air pollution have been mainly associated with the following pollutants: sulfur dioxide and particulate matter, photochemical oxidants, nitrogen dioxide and carbon monoxide, and lead. Short-term as well as long-term effects can be expected at levels exceeding WHO guidelines. The Latin American urban areas most affected by anthropogenic pollutant emissions are: the area of São Paulo (Brazil), the city of Santiago (Chile) and the metropolitan area of Mexico City. However, situations similar to those prevailing in these cities could well occur in other cities of Latin America and the Caribbean. The population exposed to air-pollutant levels exceeding WHO guidelines can be estimated to 81 million or 26.5% of the total urban population of Latin America and 19% of its total population. These estimates correspond to 30 million children (0-14), 47 million adults (15-59) and 4 million elderly people (60+). To date a very limited number of epidemiological studies have been carried out to determine the potential health effects of air pollutants in Latin America. To obtain a rough estimate, a scenario was hypothesized in which subjects living in cities would be exposed to a given level of air pollutant, using data from the international literature to extrapolate the expected number of events in different strata of the hypothetical population. The estimated health effects are considerable and warrant priority control intervention. This is true although epidemiological studies are needed to evaluate the health impact of specific pollutant compounds as well as their interactions in Latin American populations exposed to high levels of pollution.