Heavy metal release from different ashes during serial batch tests using water and acid

Most ashes contain a significant amount of heavy metals and when released from disposed or used ash materials, they can form a major environmental concern for underground waters. The use of water extracts to assess the easily mobilisable content of heavy metals may not provide an appropriate measure. This study describes the patterns of heavy metal release from ash materials in context with results from the German standard extraction method DIN-S4 (DIN 38 414 S4). Samples of four different ashes (municipal solid waste incineration ash, wood ash, brown coal ash and hard coal ash) were subjected to a number of serial batch tests with liquid renewal, some of which involved the addition of acid to neutralize carbonates and oxides. Release of heavy metals showed different patterns depending on the element, the type of material, the method of extraction and the type of the extractant used. Only a small fraction of the total heavy metal contents occurred as water soluble salts; of special significance was the amount of Cr released from the wood ash. The reaction time (1, 24 or 72 h between each extraction step with water) had only a small effect on the release of heavy metals. However, the release of most of the heavy metals was governed by the dissolution processes following proton inputs, indicating that pH-dependent tests such as CEN TC 292 or others are required to estimate long-term effects of heavy metal releases from ashes. Based on the chemical characteristics of ash materials in terms of their form and solubility of heavy metals, recommendations were made on the disposal or use of the four ash materials.     

Emotion as mediators of the relations between perceived supervisor support and psychological hardiness on employee cynicism

In this study we explore whether emotion experienced at work mediates the relationships between perceived supervisor support, psychological hardiness, and employee cynicism. Data were collected from employees working at a medical technology company located in Switzerland. Mediational analyses showed that employees' positive and negative emotions experienced amidst an organizational crisis fully accounted for the relations between perceived supervisor support and cynicism and psychological hardiness and cynicism. Practical implications and directions for future research are discussed. Copyright © 2006 John Wiley & Sons, Ltd.     

Influence of platinum, palladium and rhodium as compared with cadmium, nickel and chromium on cell viability and oxidative stress in human bronchial epithelial cells

The platinum group elements (PGE) Pt, Pd and Rh are increasingly emitted into the environment by automobile catalytic converters. Whereas the biological availability of PGE to plants and animals has been demonstrated, only few studies concentrate on the influence of PGE on a cellular level. The effects of Pt, Pd and Rh compared with Cd, Ni and Cr on cell viability and oxidative stress response using soluble metal salts were studied in the human bronchial epithelial cell line BEAS-2B. Whilst Rh(III) showed little influence, both Pt(II) and Pt(IV) as well as Pd(II) had significant effects on cell viability at levels comparable to Cd(II) and Cr(VI). Arranging metal species in order of increasing toxicity as determined by LC50 yields: Rh(III)=1.2 mmol/L相似文献   

The effect of the Sars-Cov-2 pandemic on the use of personal protective equipment in hospitals

The Covid pandemic has strongly affected the use of personal protective equipment (PPE) in the medical sector. Our aim was to assess the influence of Covid on PPE use within a German hospital by analyzing PPE use in four years prior to Covid and in 2020/2021. Numbers of items and mass of different types of PPE were determined based on procurement data. The results show that for the use of gloves the pandemic only had a small effect on the number of items. For body protection there was a clear trend toward a decrease in the number of items used in the years before the pandemic due to actions by the hospital toward a better environmental footprint which was partially reversed by the pandemic. The number of masks on the other hand doubled during the pandemic. Expressed in mass of PPE per patient and day, 15 g of masks, 121 g of gloves, and 183 g of body protection are used, resulting in a total of 319 g of PPE per patient and day. As medical waste has a specific treatment, no direct environmental effects of PPE use in hospitals in a region with well-developed waste treatment system are expected.

     

Combined application of marble waste and beneficial microorganisms: toward a cost-effective approach for restoration of heavy metals contaminated sites

Environmental Science and Pollution Research - Heavy metal (HM) pollution and the need to preserve the environment have gathered increasing scientific attention. The immobilization of HMs into...