1,273 research outputs found

    Ecotoxicity of raw and treated effluents generated by a veterinary medicine industry

    Get PDF
    Effluents from veterinary pharmaceutical industries that formulate medicines are mainly generated during the washing of equipment. The aim of this work was to evaluate the acute toxicity to Daphnia similis and chronic toxicity to Ceriodaphnia dubia of raw and treated effluents generated by a veterinary pharmaceutical industry. The industrial effluent treatment system comprises a step of chemical treatment (coagulation-sedimentation forced) followed by aerobic biological treatment (activated sludge process). Five samplings campaigns were performed from October 2011 to July 2012. The raw effluent samples showed high acute and chronic toxicity (acute: fourth sampling with EC50 - 48-h of <0.001% and chronic: third sampling with IC50 - 7-d of <0.0001%). The chemically treated effluent samples were the most toxic with EC50 - 48-h between <0.001 and 0.1% and IC50 - 7-d between 0.00001 and 0.0001%. This increase in toxicity is probably related to the use of aluminum sulfate as flocculating agent. The biological treatment led to a small reduction in toxicity of the effluents. The selected ecotoxicological tests were adequate for detecting the effluent toxicity and useful for evaluating the efficiency of the steps of the effluent treatment. Improvements in the industrial wastewater treatment system should be implemented in order to reduce the observed toxicity of the final effluent.Efluentes de indústrias farmacêuticas veterinárias, que formulam medicamentos, são gerados principalmente durante a lavagem dos equipamentos. O objetivo desse trabalho foi avaliar a toxicidade aguda para Daphnia similis e crônica para Ceriodaphnia dubia, dos efluentes brutos e tratados gerados por uma indústria farmacêutica veterinária. O sistema de tratamento de efluentes usado é composto por uma etapa de tratamento químico (coagulação-sedimentação forçada) seguida do tratamento biológico aeróbio (processo de lodos ativados). Foram realizadas 5 campanhas de amostragens entre outubro de 2011 e julho de 2012. As amostras de efluentes brutos apresentaram elevada toxicidade aguda e crônica (aguda: quarta campanha com CE50 - 48-h de <0,001% e crônica: terceira campanha com CI50 - 7d <0,0001%). As amostras de efluentes tratados quimicamente foram as mais tóxicas com CE50 - 48-h entre <0,001 e 0,1% e CI50 - 7-d entre 0,00001 e 0,0001%, provavelmente relacionada ao uso de sulfato de alumínio como agente floculante. O tratamento biológico levou a uma pequena diminuição da toxicidade dos efluentes. Os testes ecotoxicológicos foram adequados para detectar a toxicidade dos efluentes e úteis para avaliar a eficiência das etapas do tratamento. Melhorias no sistema de tratamento de efluentes da indústria estudada deveriam ser implementadas visando à redução da toxicidade observada nos efluentes finais.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Universidade Federal de Alfenas Instituto de Ciências da NaturezaUniversidade Estadual de Campinas Laboratório de Ecotoxicologia Aquática e Limnologia Prof. Dr. Abílio LopesUniversidade Federal de São Paulo (UNIFESP) Instituto de Ciências Ambientais, Químicas e FarmacêuticasUNIFESP, Instituto de Ciências Ambientais, Químicas e FarmacêuticasSciEL

    Ecotoxicity of raw and treated effluents generated by a veterinary medicine industry

    Get PDF
    Effluents from veterinary pharmaceutical industries that formulate medicines are mainly generated during the washing of equipment. The aim of this work was to evaluate the acute toxicity to Daphnia similis and chronic toxicity to Ceriodaphnia dubia of raw and treated effluents generated by a veterinary pharmaceutical industry. The industrial effluent treatment system comprises a step of chemical treatment (coagulation-sedimentation forced) followed by aerobic biological treatment (activated sludge process). Five samplings campaigns were performed from October 2011 to July 2012. The raw effluent samples showed high acute and chronic toxicity (acute: fourth sampling with EC50 - 48-h of <0.001% and chronic: third sampling with IC50 - 7-d of <0.0001%). The chemically treated effluent samples were the most toxic with EC50 - 48-h between <0.001 and 0.1% and IC50 - 7-d between 0.00001 and 0.0001%. This increase in toxicity is probably related to the use of aluminum sulfate as flocculating agent. The biological treatment led to a small reduction in toxicity of the effluents. The selected ecotoxicological tests were adequate for detecting the effluent toxicity and useful for evaluating the efficiency of the steps of the effluent treatment. Improvements in the industrial wastewater treatment system should be implemented in order to reduce the observed toxicity of the final effluent.Efluentes de indústrias farmacêuticas veterinárias, que formulam medicamentos, são gerados principalmente durante a lavagem dos equipamentos. O objetivo desse trabalho foi avaliar a toxicidade aguda para Daphnia similis e crônica para Ceriodaphnia dubia, dos efluentes brutos e tratados gerados por uma indústria farmacêutica veterinária. O sistema de tratamento de efluentes usado é composto por uma etapa de tratamento químico (coagulação-sedimentação forçada) seguida do tratamento biológico aeróbio (processo de lodos ativados). Foram realizadas 5 campanhas de amostragens entre outubro de 2011 e julho de 2012. As amostras de efluentes brutos apresentaram elevada toxicidade aguda e crônica (aguda: quarta campanha com CE50 - 48-h de <0,001% e crônica: terceira campanha com CI50 - 7d <0,0001%). As amostras de efluentes tratados quimicamente foram as mais tóxicas com CE50 - 48-h entre <0,001 e 0,1% e CI50 - 7-d entre 0,00001 e 0,0001%, provavelmente relacionada ao uso de sulfato de alumínio como agente floculante. O tratamento biológico levou a uma pequena diminuição da toxicidade dos efluentes. Os testes ecotoxicológicos foram adequados para detectar a toxicidade dos efluentes e úteis para avaliar a eficiência das etapas do tratamento. Melhorias no sistema de tratamento de efluentes da indústria estudada deveriam ser implementadas visando à redução da toxicidade observada nos efluentes finais.168179Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Caminhos percorridos no mapa da portuguesificação: A Linguateca em perspectiva

    Get PDF
    This study evaluated the ecotoxicity of five dyes to freshwater organisms before and during their photo-Fenton degradation. EC50 (48 h) of the five tested dyes ranged from of 6.9 to >1000 mg L-1 for Daphnia similis. In the chronic tests IC50 (72 h) varied from 65 to >100 mg L-1 for Pseudokirchneriella subcapitata and IC50 (8 days) from 0.5 to 410 mg L-1 for Ceriodaphnia dubia. Toxicity tests revealed that although the applied treatment was effective for decolorization of the dye, the partial mineralization may be responsible for the presence of degradation products which can be either more toxic than the original dye, as is the case of Vat Green 3 and Reactive Black 5, lead to initially toxic products which may be further degraded to non toxic products (acid Orange 7 and Food Red 17), or generate non toxic products as in the case of Food Yellow 3. The results highlighted the importance of assessing both acute and chronic toxicity tests of treated sample before effluent discharge. (C) 2014 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

    All-particle cosmic ray energy spectrum measured by the HAWC experiment from 10 to 500 TeV

    Full text link
    We report on the measurement of the all-particle cosmic ray energy spectrum with the High Altitude Water Cherenkov (HAWC) Observatory in the energy range 10 to 500 TeV. HAWC is a ground based air-shower array deployed on the slopes of Volcan Sierra Negra in the state of Puebla, Mexico, and is sensitive to gamma rays and cosmic rays at TeV energies. The data used in this work were taken from 234 days between June 2016 to February 2017. The primary cosmic-ray energy is determined with a maximum likelihood approach using the particle density as a function of distance to the shower core. Introducing quality cuts to isolate events with shower cores landing on the array, the reconstructed energy distribution is unfolded iteratively. The measured all-particle spectrum is consistent with a broken power law with an index of 2.49±0.01-2.49\pm0.01 prior to a break at (45.7±0.1(45.7\pm0.1) TeV, followed by an index of 2.71±0.01-2.71\pm0.01. The spectrum also respresents a single measurement that spans the energy range between direct detection and ground based experiments. As a verification of the detector response, the energy scale and angular resolution are validated by observation of the cosmic ray Moon shadow's dependence on energy.Comment: 16 pages, 11 figures, 4 tables, submission to Physical Review

    Constraining the pˉ/p\bar{p}/p Ratio in TeV Cosmic Rays with Observations of the Moon Shadow by HAWC

    Get PDF
    An indirect measurement of the antiproton flux in cosmic rays is possible as the particles undergo deflection by the geomagnetic field. This effect can be measured by studying the deficit in the flux, or shadow, created by the Moon as it absorbs cosmic rays that are headed towards the Earth. The shadow is displaced from the actual position of the Moon due to geomagnetic deflection, which is a function of the energy and charge of the cosmic rays. The displacement provides a natural tool for momentum/charge discrimination that can be used to study the composition of cosmic rays. Using 33 months of data comprising more than 80 billion cosmic rays measured by the High Altitude Water Cherenkov (HAWC) observatory, we have analyzed the Moon shadow to search for TeV antiprotons in cosmic rays. We present our first upper limits on the pˉ/p\bar{p}/p fraction, which in the absence of any direct measurements, provide the tightest available constraints of 1%\sim1\% on the antiproton fraction for energies between 1 and 10 TeV.Comment: 10 pages, 5 figures. Accepted by Physical Review

    Search for very-high-energy emission from Gamma-ray Bursts using the first 18 months of data from the HAWC Gamma-ray Observatory

    Full text link
    The High Altitude Water Cherenkov (HAWC) Gamma-ray Observatory is an extensive air shower detector operating in central Mexico, which has recently completed its first two years of full operations. If for a burst like GRB 130427A at a redshift of 0.34 and a high-energy component following a power law with index -1.66, the high-energy component is extended to higher energies with no cut-off other than from extragalactic background light attenuation, HAWC would observe gamma rays with a peak energy of \sim300 GeV. This paper reports the results of HAWC observations of 64 gamma-ray bursts (GRBs) detected by Swift\mathit{Swift} and Fermi\mathit{Fermi}, including three GRBs that were also detected by the Large Area Telescope (Fermi\mathit{Fermi}-LAT). An ON/OFF analysis method is employed, searching on the time scale given by the observed light curve at keV-MeV energies and also on extended time scales. For all GRBs and time scales, no statistically significant excess of counts is found and upper limits on the number of gamma rays and the gamma-ray flux are calculated. GRB 170206A, the third brightest short GRB detected by the Gamma-ray Burst Monitor on board the Fermi\mathit{Fermi} satellite (Fermi\mathit{Fermi}-GBM) and also detected by the LAT, occurred very close to zenith. The LAT measurements can neither exclude the presence of a synchrotron self-Compton (SSC) component nor constrain its spectrum. Instead, the HAWC upper limits constrain the expected cut-off in an additional high-energy component to be less than 100 GeV100~\rm{GeV} for reasonable assumptions about the energetics and redshift of the burst.Comment: 19 pages, 6 figures, published in Ap

    Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory

    Get PDF
    Atmospheric parameters, such as pressure (P), temperature (T) and density, affect the development of extensive air showers initiated by energetic cosmic rays. We have studied the impact of atmospheric variations on extensive air showers by means of the surface detector of the Pierre Auger Observatory. The rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find that the observed behaviour is explained by a model including the effects associated with the variations of pressure and density. The former affects the longitudinal development of air showers while the latter influences the Moliere radius and hence the lateral distribution of the shower particles. The model is validated with full simulations of extensive air showers using atmospheric profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle Physic

    Search for the standard model Higgs boson in tau final states

    Get PDF
    We present a search for the standard model Higgs boson using hadronically decaying tau leptons, in 1 inverse femtobarn of data collected with the D0 detector at the Fermilab Tevatron ppbar collider. We select two final states: tau plus missing transverse energy and b jets, and tau+ tau- plus jets. These final states are sensitive to a combination of associated W/Z boson plus Higgs boson, vector boson fusion and gluon-gluon fusion production processes. The observed ratio of the combined limit on the Higgs production cross section at the 95% C.L. to the standard model expectation is 29 for a Higgs boson mass of 115 GeV.Comment: publication versio

    Search for the associated production of a b quark and a neutral supersymmetric Higgs boson which decays to tau pairs

    Get PDF
    We report results from a search for production of a neutral Higgs boson in association with a bb quark. We search for Higgs decays to τ\tau pairs with one τ\tau subsequently decaying to a muon and the other to hadrons. The data correspond to 2.7fb1^{-1} of \ppbar collisions recorded by the D0 detector at s=1.96\sqrt{s} = 1.96TeV. The data are found to be consistent with background predictions. The result allows us to exclude a significant region of parameter space of the minimal supersymmetric model.Comment: Submitted to Phys. Rev. Letter
    corecore