Concentrations of Cd, Cr, Cu, Fe, Mn, Ni, Pb, Ti, V, and Zn in particulate matter (PM)
10
ambient air samples were determined for the urban zone of Tampico, Mexico every 6 days during 2004. A Wedding ...and Associates PM
10
high-volume sampler was used to collect the particles on quartz and glass fiber filters. A Thermo Jarrel Ash inductively coupled plasma-optical emission spectrometer (ICP-OES) was used to identify and quantify metals in PM
10
according to the USEPA-IO 3.1 method. A scanning electron microscope with an energy dispersive spectrometer (SEM-EDS) was used to analyze the elemental composition, size, and morphology of atmospheric particles. Principal component factor analysis (PCFA) was used to study the sources of PM
10
and metals. PM
10
and Pb concentrations in Tampico did not exceed the Mexican standard value of 120 and 1.5 μg m
−3
in 24 h, respectively. PM
10
concentrations ranged from 12 to 47 μg m
−3
. The results for Cd, Cr, and Cu are associated to the presence of an industrial source near the sampling site. V and Zn and likely Pb and Ni are related to a refinery. Fe and Ti are associated to natural sources, whereas Cu, Fe, Ni, Pb, and Zn are associated to the storage and transportation of minerals near the sampling zone. Mn is associated to a ferromanganese manufacturing industry and to the refinery. The SEM-EDS micrographs show porous spherical particles rich in V and Ni and smooth spherical particles rich in C and O.
In order to understand the hydrogeochemical pattern, ground (n = 23) and surface water (n = 2) samples were collected from three different landscapes (mountain, plain, valley) of Hidalgo State, ...Central Mexico. Physicochemical characteristics (pH, electrical conductivity, total hardness, alkalinity, total acidity, total solids, total dissolved solids, total suspended solids, CO2; cations (Ca2+, Mg2+, Na+), anions (NO3−, Cl−, PO43−and SO42−) and dissolved geochemical elements (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd and As) were analyzed. Results illustrated they are neutral to slightly alkaline due to the dissolution of carbonates. Average concentrations of anions and cations presented an order of (in mg/l): Na+ (273) > Ca2+ (206) > SO42− (181) > Cl− (163) > Mg2+ (115) > NO3− (11.07) > PO43− (0.12) revealing the local geogenic and anthropogenic influences. High mean concentrations of dissolved trace metals (0.052 mg/l) in the mountains is attributed to their diverse geochemical environment of the terrain and climatic variability. Concentrations of Cr, Cu, Ni and Zn were below the permissible limits set forth by WHO and the Mexican Government. Piper trilinear diagram revealed that they are mainly of Ca-Mg-HCO3 and Ca-Mg-SO4 type. Sodium Absorption Ratio (SAR) indicated that nearly 96% are of excellent quality, while Magnesium Adsorption Ratio (MAR) showed that 68% of them are unsuitable for irrigation purposes.
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The Valsequillo reservoir is a Ramsar wetland due to its importance as a point of convergence of migratory waterfowl. It is located in Central Mexico and is currently endangered by the constant spill ...of municipal and industrial discharges from Puebla city. On this context, we evaluated thirteen potential toxic metals (PTMs) in water, Water hyacinth (E. crassipes) plants and sediments at this site. A combined number of 31 samples were collected from the study area. The degree/extent of metal contamination in sediments was assessed through different geochemical indexes, namely: Geoaccumulation index (Igeo), Enrichment Factor (EF) and Potential Ecological Risk Index (PERI). The ability of Water hyacinth plants residues as a phytodepurator in the Ramsar site was tested in terms of the bioaccumulation factor (BF) and the translocation factor (TF). The results concerning sediments showed that Pb, Cu and Hg pose a threat to the aquatic environment since Igeo and EF indicate sediments ranging from moderately contaminated to contaminated. Moreover, PERI pointed out Hg as the main contributor to the ecological risk in sediments, especially in the part of the reservoir covered by E. crassipes. Water hyacinth plants displayed good capacity to absorb PTMs from the water, since the content of Co, Zn, As, Ni, Cu, Pb, Ti, Cr, Ba, Mo and V in the total plant was (all values in mg/kg of dry weight) 21 ± 9, 408 ± 300, 12 ± 6, 93 ± 21, 93 ± 69, 53 ± 29, 1067 ± 643, 78 ± 55, 362 ± 39, 14 ± 0.6 and 96 ± 35, respectively. Metal content in sediments resembles to that of E. crassipes; especially in the roots, suggesting a constant deposition of plants at the bottom of the reservoir, which contributes to the eutrophication of the water. The present work encourages the need for a sustainable management of Water hyacinth plants in the Ramsar site, since they represent a plague and a natural phyto-depurator at the same time.
With the aim to know possible risks to the population, Cd, Co, Cr, Cu, Mn, Ni, Pb, and Tl were determined for the first time in airborne samples of particulate matter in an urban zone in Tampico, ...México, during the winter of 2003. The 24-hour PM
10
samples were collected every 6 days on quartz-filters by using a high volume sampler and analyzed by Inductively Coupled Plasma Optical Emission Spectrometer. Standard reference material was used to verify metal recovery. The maximum PM
10
and lead concentrations were 12.05 and 0.040 μ g/m
3
, respectively, not exceeding Méxican standard values. The greatest metal concentration was that of manganese with 0.90 μ g/m
3
, followed by Cu and Ni with 0.17 and 0.012 μ g/m
3
, respectively. Agglomerates, well-defined particles, and heavy metals (e.g., Mn and Cu) were found in PM
10
using Scanning Electron Microscopy and Energy Dispersive Spectroscopy. Meteorological conditions associated with the sampling period showed that Pb and Ni are being continuously emitted, and that Mn, Cu, and Co could come from one industry located to the WSW of the region. All of these concentrations do not constitute a potential risk to human health, although it is necessary to continue studying the high concentrations of Mn and Cu in longer sampling periods.
Context.
Solar Orbiter strives to unveil how the Sun controls and shapes the heliosphere and fills it with energetic particle radiation. To this end, its Energetic Particle Detector (EPD) has now ...been in operation, providing excellent data, for just over a year.
Aims.
EPD measures suprathermal and energetic particles in the energy range from a few keV up to (near-) relativistic energies (few MeV for electrons and about 500 MeV nuc
−1
for ions). We present an overview of the initial results from the first year of operations and we provide a first assessment of issues and limitations. In addition, we present areas where EPD excels and provides opportunities for significant scientific progress in understanding how our Sun shapes the heliosphere.
Methods.
We used the solar particle events observed by Solar Orbiter on 21 July and between 10 and 11 December 2020 to discuss the capabilities, along with updates and open issues related to EPD on Solar Orbiter. We also give some words of caution and caveats related to the use of EPD-derived data.
Results.
During this first year of operations of the Solar Orbiter mission, EPD has recorded several particle events at distances between 0.5 and 1 au from the Sun. We present dynamic and time-averaged energy spectra for ions that were measured with a combination of all four EPD sensors, namely: the SupraThermal Electron and Proton sensor (STEP), the Electron Proton Telescope (EPT), the Suprathermal Ion Spectrograph (SIS), and the High-Energy Telescope (HET) as well as the associated energy spectra for electrons measured with STEP and EPT. We illustrate the capabilities of the EPD suite using the 10 and 11 December 2020 solar particle event. This event showed an enrichment of heavy ions as well as
3
He, for which we also present dynamic spectra measured with SIS. The high anisotropy of electrons at the onset of the event and its temporal evolution is also shown using data from these sensors. We discuss the ongoing in-flight calibration and a few open instrumental issues using data from the 21 July and the 10 and 11 December 2020 events and give guidelines and examples for the usage of the EPD data. We explain how spacecraft operations may affect EPD data and we present a list of such time periods in the appendix. A list of the most significant particle enhancements as observed by EPT during this first year is also provided.
Concentrations, sources, and relative contributions of Cd, Cr, Cu, Fe, Mn, Pb, Ni, Ti, V, and Zn observed in PM10 in the petrochemical industrial zone of Altamira in Northern Mexico are reported for ...the first time. Results show that oil refining, alloys, fertilizer, mining, metallurgical processes, and steel production industries are important contributions to PM10 and metal concentrations. PM10 concentrations ranged from 21 to 92 mug m-3 and exceeded the revised 24-h average Mexican standard NOM-025-SSA1-2014 of 75 mug m-3 12 % of the study period. The highest metal concentrations were Fe (1.64 mug m-3), Mn (0.57 mug m-3), and Ti (0.29 mug m-3) and were associated with two dominant wind directions. Ti and Fe were associated with NNW winds (natural sources), and Mn and Fe were associated with SSW winds (ferromanganese industry). An average V/Ni ratio of 8.5 was found in this study with highest ratios associated to two dominant wind directions, NNW-NW and SE-SSE, suggesting origins from a fuel oil thermoelectric power plant and a refinery fuel oil, respectively. Pb was associated with industrial activity and never exceeded the Mexican standard of 1.5 mug m-3 in 24 h. Zn and Cd were correlated with a dominant easterly wind, suggesting the presence of vehicle exhaust pollutants. The study of the size and shape of PM10 particles by scanning electronic microscopy and energy-dispersive spectroscopy (SEM-EDS) allowed us to confirm the presence of trace metals associated to natural soils and clays, combustion, and industrial processes. The results presented here constitute the first efforts to evaluate toxic metals in a heavily industrialized area in Mexico and can be used to develop air quality management programs.
Concentrations, sources, and relative contributions of Cd, Cr, Cu, Fe, Mn, Pb, Ni, Ti, V, and Zn observed in PM sub(10) in the petrochemical industrial zone of Altamira in Northern Mexico are ...reported for the first time. Results show that oil refining, alloys, fertilizer, mining, metallurgical processes, and steel production industries are important contributions to PM sub(10) and metal concentrations. PM sub(10) concentrations ranged from 21 to 92 mu g m super(-3) and exceeded the revised 24-h average Mexican standard NOM-025-SSA1-2014 of 75 mu g m super(-3) 12 % of the study period. The highest metal concentrations were Fe (1.64 mu g m super(-3) ), Mn (0.57 mu g m super(-3) ), and Ti (0.29 mu g m super(-3) ) and were associated with two dominant wind directions. Ti and Fe were associated with NNW winds (natural sources), and Mn and Fe were associated with SSW winds (ferromanganese industry). An average V/Ni ratio of 8.5 was found in this study with highest ratios associated to two dominant wind directions, NNW-NW and SE-SSE, suggesting origins from a fuel oil thermoelectric power plant and a refinery fuel oil, respectively. Pb was associated with industrial activity and never exceeded the Mexican standard of 1.5 mu g m super(-3) in 24 h. Zn and Cd were correlated with a dominant easterly wind, suggesting the presence of vehicle exhaust pollutants. The study of the size and shape of PM sub(10) particles by scanning electronic microscopy and energy-dispersive spectroscopy (SEM-EDS) allowed us to confirm the presence of trace metals associated to natural soils and clays, combustion, and industrial processes. The results presented here constitute the first efforts to evaluate toxic metals in a heavily industrialized area in Mexico and can be used to develop air quality management programs.
Between 1999 and 2005, 233 stranded cetaceans (comprising 19 species) were reported in the waters of the Canary Islands. Of these, 138/233 (59.2%) were subjected to a complete or partial standardized ...necropsy, including 4 Balaenopteridae, 9 Physeteridae, 8 Kogiidae, 27 Ziphiidae and 90 Delphinidae. Of these, 46/138 (33.3%) cetaceans were diagnosed with anthropogenic pathological categories (i.e. the cause of death was anthropogenic). These included fishing interaction (bycatch) (19 individuals), 'atypical' mass stranding events linked to naval exercises (13), ship collisions (8) and other anthropogenic-related pathology (6). 'Natural' (i.e. non-anthropogenic) causes of death accounted for another 82/138 (59.4%) cases, including infectious and non-infectious diseases (63), neonatal pathology (8), intra- and interspecific interactions (6) and mass strandings (5). The cause(s) of death could not be determined in 10/138 (7.3%) necropsied animals. The most common causes of death were ship collisions in 6/9 (66.6%) Physeteridae, 'atypical' mass stranding linked to naval exercises in 13/27 (48.1%) Ziphiidae, and 'natural' infectious and non-infectious diseases in 55/90 (61.1%) Delphinidae. Interaction with fishing activities was established as cause of death in 15/90 (16.7%) Delphinidae. These data show that a range of anthropogenic and natural single and mass mortality events occur in multiple cetacean species stranded in the Canary Islands.
Recent theoretical and observational works indicate the presence of a correlation between the star-formation rate (SFR) and active galactic nucleus (AGN) luminosity (and, therefore, the black hole ...accretion rate, M sub(BH)) of Seyfert galaxies. This suggests a physical connection between the gas-forming stars on kpc scales and the gas on sub-pc scales that is feeding the black hole. We compiled the largest sample of Seyfert galaxies to date with high angular resolution (~0."4-0."8) mid-infrared (8-13 mu m) spectroscopy. The sample includes 29 Seyfert galaxies drawn from the AGN Revised Shapley-Ames catalog. At a median distance of 33 Mpc, our data allow us to probe nuclear regions on scales of ~65 pc (median value). We found no general evidence of suppression of the 11.3 mu m polycyclic aromatic hydrocarbon (PAH) emission in the vicinity of these AGN, and we used this feature as a proxy for the SFR. We detected the 11.3 mu m PAH feature in the nuclear spectra of 45% of our sample. The derived nuclear SFRs are, on average, five times lower than those measured in circumnuclear regions of 600 pc in size (median value). However, the projected nuclear SFR densities (median value of 22 M sub(middot in circle) yr super(-1) kpc super(-2)) are a factor of 20 higher than those measured on circumnuclear scales. This indicates that the SF activity per unit area in the central ~65 pc region of Seyfert galaxies is much higher than at larger distances from their nuclei. We studied the connection between the nuclear SFR and M sub(BH) and showed that numerical simulations reproduce our observed relation fairly well.
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