523 research outputs found

    Heavy metal content of vegetables irrigated with mixtures of wastewater and sewage sludge in Zimbabwe: Implications for human health

    Get PDF
    There is growing public concern in Zimbabwe over the illegal cultivation of vegetables on soils amended with sewage sludge or irrigated with admixtures of sewage and sewage sludge. Excessive accumulation of heavy metals in agricultural soils may not only result in environmental contamination, but lead to elevated heavy metal uptake by crops, which may affect food quality and safety. The work reported here studied heavy metal concentrations in crops irrigated with sewage sludge and sewage/sewage sludge admixtures at Firle Municipal Farm in Harare. The crops analysed in this study are heavily contaminated with the four regulated elements Cd, Cu, Pb and Zn. This contamination is at its highest in two of the staple dietary crops maize and tsunga. Tsunga leaves contained 3.68 mg kg-1 Cd, over 18 times the permissible level by the EU standards (0.2 mg kg-1); Cu concentrations were 111 mg kg-1, 5 times the EU Standard (20 mg kg-1); concentrations of Pb were 6.77 mg kg-1, over 22 times the permissible levels allowed by both EU standards and UK guidelines (0.3 mg kg-1); Zn concentrations were 221 mg kg-1, over 4 times the guideline value (50 mg kg-1). The other plants (beans, maize, peppers and sugarcane) also contained concentrations of heavy metals above the permissible levels. Furthermore the concentrations observed in this study were higher than those reported by other workers who have examined vegetation from other contaminated sites. This study highlights the potential risks involved in the cultivation and consumption of vegetables on plots irrigated with sewage sludge, a practice which may place at risk the health of the urban population who consume these vegetables

    Measurement of 73 Ge(n,ő≥) cross sections and implications for stellar nucleosynthesis

    Get PDF
    ¬© 2019 The Author(s). Published by Elsevier B.V.73 Ge(n,ő≥) cross sections were measured at the neutron time-of-flight facility n_TOF at CERN up to neutron energies of 300 keV, providing for the first time experimental data above 8 keV. Results indicate that the stellar cross section at kT=30 keV is 1.5 to 1.7 times higher than most theoretical predictions. The new cross sections result in a substantial decrease of 73 Ge produced in stars, which would explain the low isotopic abundance of 73 Ge in the solar system.Peer reviewe

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in ‚ąös = 7 TeV pp collisions with the ATLAS detector

    Get PDF
    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb‚ąí1 of proton‚Äďproton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Measurement of the inclusive isolated prompt photon cross-section in pp collisions at sqrt(s)= 7 TeV using 35 pb-1 of ATLAS data