Cuantificación de metales en sedimentos superficiales de la bahía interior, lago Titicaca-Perú

TIn aquatic ecosystems, sediments are reservoirs of heavy metals when their waters are exposed. The purpose of the study was to quantify metals in surface sediments of the interior bay of Puno, Lake Titicaca, Peru. From january to november 2016 of Cu, Zn, Pb, Cd, As and Hg concentrations were analyzed in the surface sediments of six selected environmental sampling stations by non-probabilistic sampling for convenience. The metals were analyzed by acid digestion where their quantification was by inductively coupled plasma spectrometry with axial view (ICP-AES). When comparing the results with the selected environmental standard, all the elements had concentrations in the recommended ranges, although statistically significant differences existed between the stations (p<0,05). The As and Hg, presented similarities in their values (0,0001 mg.L-1) between the stations. As and Hg, presented similarities in their values between the stations. It was concluded that, the surface sediments of the inner bay of Puno do not present risk due to exposure to total metals, since their concentrations were in the range of allowable values.En ecosistemas acuáticos, los sedimentos son reservorios de metales pesados cuando sus aguas se encuentran expuestas. El propósito del estudio fue cuantificar metales en sedimentos superficiales de la bahía interior de Puno, Lago Titicaca-Perú. De enero a noviembre del 2016 fueron analizadas las concentraciones de Cu, Zn, Pb, Cd, As y Hg en los sedimentos superficiales de seis estaciones de muestreo ambiental seleccionadas mediante un muestreo no probabilístico por conveniencia. Los metales se analizaron por digestión ácida donde su cuantificación fue mediante espectrometría de plasma inductivamente acoplado con vista axial (ICP-AES). Al comparar los resultados con la norma ambiental seleccionada (Interim Sediment Quality Guidelin, Canadá), todos los elementos presentaron concentraciones en los rangos recomendados, aunque existió entre las estaciones, diferencias estadísticamente significativas (p<0,05). El As y Hg, presentaron similitudes en sus valores (0,0001 mg.L-1) entre las estaciones. Se concluyó que, los sedimentos superficiales de la bahía interior de Puno, no representan riesgo por exposición a metales totales, ya que sus concentraciones se encontraron en el rango de los valores permisibles

Determinación interactiva de metales totales en las aguas de la bahía interior del Lago Titicaca- Puno Perú

ABSTRACT The inner Puno bay is a restricted area and one of the habitats of Lake Titicaca with high anthropization, where some organic and inorganic elements may be exceeding the thresholds allowable concentrations. The aim of the research was to determine interactively total metals available in the waters of the inner Puno bay of Lake Titicaca, Peru. It was conducted between January and November 2016 by a non-probabilistic for convenience and applying the theoretical method by comparison among six stations of selection. Cu, Zn, Pb, Cd, As, Hg were the determined and quantified elements using atomic absorption spectrometry by inductively coupled plasma with axial view (ICP-AES). It was observed that between the stations there were no statistically significant differences (p ≤ 0.05) when there was an availability of exposure among all the elements, although when comparing each element per station, there were differences for the rainy (January-February-March) and dry season (September-October-November). By comparing each station and between seasons, we found that there was no statistically significant difference, although the higher concentration levels were for the dryness season. We conclude that there is environmental exposure by metals in the waters of the Inner Bay and where their concentrations are permanent during the whole period of the year, being able to bring negative consequences not only for the ecosystem, but also to the human health itself given activities of community benefit that are developed in this geographic space.Resumen La bahía interior de Puno, es un área restringida (16.0 km2) y representa uno de los hábitats del Lago Titicaca con alto nivel de antropización, donde algunos elementos orgánicos e inorgánicos podrían estar superando las concentraciones umbrales permisibles. El objetivo de la investigación fue determinar en forma interactiva los metales totales disponibles en las aguas de la bahía interior del Lago Titicaca, Perú. Se realizó, entre enero y noviembre del 2016, mediante un muestreo no probabilístico por conveniencia y aplicando el método teórico por comparación entre seis estaciones de selección. El Cu, Zn, Pb, Cd, As, Hg fueron los elementos determinados y cuantificados mediante espectrometría de absorción atómica por plasma inductivamente acoplado con vista axial (ICP-AES). Se observó que entre las estaciones no hubo diferencias estadísticamente significativas (p≤0.05) cuando existió una disponibilidad de exposición entre todos los elementos, aunque al comparar cada elemento por estación, existieron diferencias para las épocas de lluvia (enero-febrero-marzo) y estiaje (septiembre-octubre-noviembre). Al comparar cada estación y entre épocas, no existió diferencias estadísticamente significativas, aunque los mayores niveles de concentración correspondieron a la época de estiaje. Se concluyó que existe exposición ambiental por metales en las aguas de la Bahía Interior y donde sus concentraciones son permanentes durante todo el período del año, pudiendo traer consecuencias negativas no solo para el ecosistema, sino además a la propia salud humana dada actividades de beneficio comunitario que se desarrolla en este espacio geográfico. Palabras claves: agua, metales, toxicología ambiental, bahía interior de Puno-Perú.

Heavy flavour decay muon production at forward rapidity in proton–proton collisions at √s=7 TeV

The production of muons from heavy flavour decays is measured at forward rapidity in proton–proton collisions at √s=7 TeV collected with the ALICE experiment at the LHC. The analysis is carried out on a data sample corresponding to an integrated luminosity Lint=16.5 nb−1. The transverse momentum and rapidity differential production cross sections of muons from heavy flavour decays are measured in the rapidity range 2.5<y<4, over the transverse momentum range 2<pt<12 GeV/c. The results are compared to predictions based on perturbative QCD calculations

Multi-strange baryon production in pp collisions at √s=7 TeV with ALICE

A measurement of the multi-strange Ξ− and Ω− baryons and their antiparticles by the ALICE experiment at the CERN Large Hadron Collider (LHC) is presented for inelastic proton–proton collisions at a centre-of-mass energy of 7 TeV. The transverse momentum (pT) distributions were studied at mid-rapidity (|y|6.0 GeV/c. We also illustrate the difference between the experimental data and model by comparing the corresponding ratios of (Ω−+Ω¯+)/(Ξ−+Ξ¯+) as a function of transverse mass

Coherent J/ψ photoproduction in ultra-peripheral Pb–Pb collisions at √sNN=2.76 TeV

The ALICE Collaboration has made the first measurement at the LHC of J/ψ photoproduction in ultra-peripheral Pb–Pb collisions at sNN=2.76 TeV. The J/ψ is identified via its dimuon decay in the forward rapidity region with the muon spectrometer for events where the hadronic activity is required to be minimal. The analysis is based on an event sample corresponding to an integrated luminosity of about 55 μb−1. The cross section for coherent J/ψ production in the rapidity interval −3.6<y<−2.6 is measured to be dσJ/ψcoh/dy=1.00±0.18(stat)−0.26+0.24(syst) mb. The result is compared to theoretical models for coherent J/ψ production and found to be in good agreement with those models which include nuclear gluon shadowing

Inclusive J/ψ production in pp collisions at √s=2.76 TeV

The ALICE Collaboration has measured inclusive J/ψ production in pp collisions at a center-of-mass energy √s=2.76 TeV at the LHC. The results presented in this Letter refer to the rapidity ranges |y|<0.9 and 2.5<y<4 and have been obtained by measuring the electron and muon pair decay channels, respectively. The integrated luminosities for the two channels are Linte=1.1 nb−1 and Lintμ=19.9 nb−1, and the corresponding signal statistics are NJ/ψe+e−=59±14 and NJ/ψμ+μ−=1364±53. We present dσJ/ψ/dy for the two rapidity regions under study and, for the forward-y range, d2σJ/ψ/dydpt in the transverse momentum domain 0<pt<8 GeV/c. The results are compared with previously published results at s=7 TeV and with theoretical calculations

Suppression of charged particle production at large transverse momentum in central Pb–Pb collisions at √sNN=2.76 TeV

Inclusive transverse momentum spectra of primary charged particles in Pb–Pb collisions at √sNN=2.76 TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0–5% and 70–80% of the hadronic Pb–Pb cross section. The measured charged particle spectra in |η|<0.8 and 0.3<pT<20 GeV/c are compared to the expectation in pp collisions at the same sNN, scaled by the number of underlying nucleon–nucleon collisions. The comparison is expressed in terms of the nuclear modification factor RAA. The result indicates only weak medium effects (RAA≈0.7) in peripheral collisions. In central collisions, RAA reaches a minimum of about 0.14 at pT=6–7 GeV/c and increases significantly at larger pT. The measured suppression of high-pT particles is stronger than that observed at lower collision energies, indicating that a very dense medium is formed in central Pb–Pb collisions at the LHC

Two-pion Bose–Einstein correlations in central Pb–Pb collisions at √sNN=2.76 TeV

The first measurement of two-pion Bose–Einstein correlations in central Pb–Pb collisions at √sNN=2.76 TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC

Neutral pion and η meson production in proton–proton collisions at √s=0.9 TeV and s=√7 TeV

he first measurements of the invariant differential cross sections of inclusive π0 and η meson production at mid-rapidity in proton–proton collisions at s=0.9 TeV and s=7 TeV are reported. The π0 measurement covers the ranges 0.4<pT<7 GeV/c and 0.3<pT<25 GeV/c for these two energies, respectively. The production of η mesons was measured at s=√7 TeV in the range 0.4<pT<15 GeV/c. Next-to-Leading Order perturbative QCD calculations, which are consistent with the π0 spectrum at s=0.9 TeV, overestimate those of π0 and η mesons at s=√7 TeV, but agree with the measured η/π0 ratio at s=√7 TeV