Ana Gabriela Castañeda Miranda - Academia.edu (original) (raw)

Papers by Ana Gabriela Castañeda Miranda

Ecological Indicators, 2018

The use of environmental magnetism methods and biomonitors allows us the development of a low-cos... more The use of environmental magnetism methods and biomonitors allows us the development of a low-cost tool for assessing atmospheric pollution through trapped magnetic particulate matter. Such particles concentration was monitored in situ, on the lichen's thallus, using magnetic susceptibility as a pollution proxy. We studied the magnetic particle distribution on the thallus surface from weekly measurements of in situ magnetic susceptibility κ is during 16 months for seven sites. A total of ∼8300 measurements was carried out; and mean overall κ is values for each lichen varied between 4.1 and 23.9 × 10 −5 SI revealing the influence of different atmospheric pollution sources on Parmotrema pilosum, such as metallurgical factories and vehicular emissions. Weekly measurements of κ is show areas of magnetic accumulation on the thallus over a period of 60 measurement campaigns. Iron rich spherules and irregular particulate matter between PM 2.5 and PM 1.0 were observed by SEM-EDS. A joint analysis of meteorological variables and magnetic susceptibility shows an inverse relation between this magnetic parameter and temperature, i.e., a trend of decreasing κ is values during seasons of higher temperatures which tend toward higher values of atmospheric mixing height. Precipitation also affects the magnetic signal over time, producing decreases in mean values of κ is after rainy periods.

Atmospheric Pollution Research, 2016

Abstract The lichen Parmotrema pilosum is sensitive to pollution and it can live accumulating air... more Abstract The lichen Parmotrema pilosum is sensitive to pollution and it can live accumulating airborne pollutants for long time, such characteristic allows its use as biomonitor for environmental mapping in urban areas when this epiphytic specie is available. In this work, we investigated the use of such passive collector and magnetic techniques to monitor the air pollution in Tandil, a city located in Buenos Aires province with approximately 125,000 inhabitants, 60,000 vehicles and various metallurgical factories inside the urban area. The sampling strategy was carried out following a random stratified design and measuring magnetic susceptibility, magnetic hysteresis loops, anhysteretic and isothermal remanent magnetization and thermomagnetic studies to determine the magnetic properties of airborne particles accumulated on lichen samples. Scanning electron microscopy observations show particles with different morphologies (individual particles, spherules and aggregates) and composition (Fe, Al, Ni, Cr, Ti, Cu, K and Br) produced by metallurgical factories and by gaseous/solid vehicle emissions. The magnetic mineralogy shows the predominance of pseudo-single domain magnetite-like mineral and the magnetic grain size estimations indicate the presence of fine particles ( −8 m 3 kg −1 ) that are indicative of areas with high pollution loading.

Archiv der Pharmazie, 2011

A new group of regioisomeric 2,3-diaryl-1,3-benzdiazinan-4-ones, possessing a methyl sulfonyl pha... more A new group of regioisomeric 2,3-diaryl-1,3-benzdiazinan-4-ones, possessing a methyl sulfonyl pharmacophore, were synthesized and their biological activities were tested for cyclooxygenase-2 (COX-2) inhibitory activity. In vitro COX-1/COX-2 inhibition studies identified 3-(p-fluorophenyl)-2-(4methylsulfonylphenyl)-1,3-benzdiazinane-4-one (2b) as a potent and highly selective (IC 50 ¼ 0.07 mM; selectivity index ¼ 572.8) COX-2 inhibitor.

Environmental Pollution, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Atmosphere, 2018

Recently, air pollution alerts were issued in the Metropolitan Area of Aburrá Valley (AVMA) due t... more Recently, air pollution alerts were issued in the Metropolitan Area of Aburrá Valley (AVMA) due to the highest recorded levels of particulate matter (PM2.5 and PM10) ever measured. We propose a novel methodology based on magnetic parameters and an epiphytic biomonitor of air pollution in order to improve the air pollution monitoring network at low cost. This methodology relies on environmental magnetism along with chemical methods on 185 Tillandsia recurvata specimens collected along the valley (290 km2). The highest magnetic particle concentrations were found at the bottom of the valley, where most human activities are concentrated. Mass-specific magnetic susceptibility (χ) reaches mean (and s.d.) values of 93.5 (81.0) and 100.8 (64.9) × 10−8 m3 kg−1 in areas with high vehicular traffic and industrial activity, while lower χ values of 27.3 (21.0) × 10−8 m3 kg−1 were found at residential areas. Most magnetite particles are breathable in size (0.2–5 μm), and can host potentially toxi...

Ecological Indicators, 2016

Some epiphytic species accumulate airborne particles and are suitable biological indicators for m... more Some epiphytic species accumulate airborne particles and are suitable biological indicators for monitoring urban and industrial pollution. The species Tillandsia recurvata L. was studied as a monitor of air pollution in an urban area from Mexico. Individuals were collected in 25 sites which are exposed to different pollution degree and sources. The magnetic particle concentration, particle size, and mineralogy were determined and compared with chemical contents for all samples. The highest values of magnetic concentration dependent parameters were observed in industrial and heavy traffic sites (e.g., mass specific magnetic susceptibility of up to 171.5 × 10 −8 m 3 kg −1). In contrast, sites with low or without vehicular traffic reached low values (e.g., mass specific magnetic susceptibility of down to 1.8 × 10 −8 m 3 kg −1). The integrated magnetic analysis (King's and Day's plots, remanent magnetization parameters and thermomagnetic measurements) revealed the presence of ferromagnetic minerals, mostly magnetite-like with fine grain sizes (0.1-1 m) and subordinate presence of high-coercivity minerals. Selected samples were observed by SEM and EDS analysis and revealed the presence of Fe-rich particles, as well as trace elements, among others, As, Sb, S, Cr, Mo, V, Zn, Ba, Hg, Pt and Cu. Most of the elements detected by EDS were also quantified by ICP-MS measurements. Multivariate statistical analyses prove a high correlation between magnetic parameters and elements, as well as allow us classifying sites in clusters (fuzzy c-means clustering) with different pollution degree. These results demonstrate the usefulness of the species T. recurvata L. as a passive pollution monitor, with an affordable and immediate application. This species is abundant not only in Mexico, but also in other cities from America.

Ecological Indicators, 2015

Studies of magnetic monitoring for assessing air pollution have been proposed as alternative and ... more Studies of magnetic monitoring for assessing air pollution have been proposed as alternative and complimentary of chemical methods. Such magnetic studies provide measurements at low cost and relative promptness. In this work, we present and apply a methodology to build an interval fuzzy model, which calculates the Tomlinson pollution load index (PLI). The input variables for the model are magnetic parameters relative to magnetic concentration, grain size and mineralogy. The model aims to two purposes, on one hand, to calculate the values of PLI only using magnetic variables and, on the other hand, to analyze the relationship between magnetic and chemical variables. The studied dataset was obtained from measurements of the biomonitor Tillandsia recurvata L. in a Mexican urban area (Santiago de Querétaro). The best model was selected from a total of about half a million possible models using a fitness measure (RIF). The model yields a satisfactory approximation of the PLI data and it was concluded that PLI increases with relation to: an increase in concentration of magnetic materials, an additional contribution to the magnetic signal of paramagnetic materials, and an increase in size of magnetic grains.

Atmospheric Environment, 2014

ABSTRACT We present the magnetic properties of the powders collected by high volume total suspend... more ABSTRACT We present the magnetic properties of the powders collected by high volume total suspended particle air samplers used to monitor atmospheric pollution in Santiago de Querétaro, a city of one million people in central Mexico. The magnetic measurements have been combined with scanning electron microscopy observations and analysis, in order to characterize the particles captured in the filters as natural and anthropogenic. The main goal of the study is to test if magnetic measurements on the sampled atmospheric dust can be effective, low-cost, proxy to qualitatively estimate the air quality, complementing the traditional analytical methods. The magnetic properties of the powder collected in the filters have been investigated measuring the low field magnetic susceptibility, hysteresis loops, thermomagnetic curves, and isothermal remanent magnetization. The rock magnetism data have been supplemented by energy-dispersive X-ray spectroscopy analysis and Raman spectroscopy. It was found that the main magnetic carrier is low-Ti magnetite in the PSD range with a contribution from SP particles, and small but significant contributions from hematite, maghemite and goethite particles. Total suspended particles in the atmosphere during the monitored days ranged between about 30 and 280 μg/m3. Magnetic susceptibility values are well correlated with the independently determined total suspended particles concentration (R = 0.93), but particle concentration does not correlate as well with IRM1T. This may be attributed to contributions from SP and paramagnetic particles to the susceptibility signal, but not to the remanence. The effects of climate in particle size, composition and concentration were considered in terms of precipitation and wind intensity, but they are actually minor. The main effect of climate appears to be the removal of SP particles during rainy days. There is a contribution to air pollution from natural mineral sources, which we attribute to low vegetation cover in the region's arid climate. The concentration of the magnetic particles and their grain-size vary according to the location of the monitoring station, with higher contributions to anthropogenic Fe-rich particles from vehicle emissions in the city center and other metals in the industrial parks. Metals of interest, usually diagnostic of atmospheric pollution (Fe, As, Sb, Cr, Mo, V, Zn, Ba, Pb, and Cu) were identified by means of electron microscopy.

Environmental Monitoring and Assessment, 2020

There are limited economic and reliable tools to monitor the effects of airborne particulate matt... more There are limited economic and reliable tools to monitor the effects of airborne particulate matter PM originating from rapid industrialization, urbanization, population growth, and economic development. It is now well established that urban PM contains magnetic particles along with other air pollutants. The velocity and temporal variability of the deposition of such PM on tree leaves are subject to the pollution sources, climate, and local atmospheric conditions. Therefore, these variables have to be taken into account during a biomonitoring. This study presents a magnetic biomonitoring in the city of Querétaro. In the city’s metropolitan area, the most abundant and perennial tree species for biomonitoring is Ficus benjamina. For leaves of this species, the number of days needed for collection NDNC was measured, taking into account the meteorological conditions and the time at which they reached the saturation of airborne PM (pollutants). By means of sequential sampling, we identified that the minimum NDNC after a rainfall > 3 mm is 15 days. In such a period, total suspended particle TSP depositions reach its dynamic equilibrium. This behavior can be observed from measurements of specific magnetic susceptibility χ in Ficus benjamina samples and their comparison with TSP depositions collected with traditional Hi-Vol monitoring systems. After the NDNC calculation, a magnetic monitoring was performed with the biomonitor Ficus benjamina to evaluate the air quality at different sites in the metropolitan area every month for a period of 5 months. Values of χ ranged from 0.45 to 18.52 × 10−8m3kg−1. The species Ficus benjamina can be used as a biomonitor in the city of Querétaro only in seasons (winter-spring) with no or low rainfall. The species has the advantage of providing current PM information about a specific period of time.