Heavy metal (chemistry)
hideA heavy metal is a member of an ill-defined subset of elements that exhibit metallic properties, which would mainly include the transition metals, some metalloids, lanthanides, and actinides. Many different definitions have been proposed—some based on density, some on atomic number or atomic weight, and some on chemical properties or toxicity. The term heavy metal has been called "meaningless and misleading" in an IUPAC technical report due to the contradictory definitions and its lack of a "coherent scientific basis". There is an alternative term toxic metal, for which no consensus of exact definition exists either. As discussed below, depending on context, heavy metal can include elements lighter than carbon and can exclude some of the heaviest metals. Heavy metals occur naturally in the ecosystem with large variations in concentration. Nowadays anthropogenic sources of heavy metals, i.e. pollution, have been introduced to the ecosystem. Waste derived fuels are especially prone to contain heavy metals so they should be a central concern in a consideration of their use.
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News tagged with heavy metals
Heavy metal paradox could point toward new therapy for Lou Gehrig's disease
Medicine & Health / Neuroscience
27 minutes ago |
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New discoveries have been made about how an elevated level of lead, which is a neurotoxic heavy metal, can slow the progression of amyotrophic lateral sclerosis, or Lou Gehrig's disease - findings that could point the way ...
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Super Typhoon Nida to pass east of Iwo To and Chichi Jima
Space & Earth / Earth Sciences
5 hours ago |
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Nida is still holding on to Super Typhoon status in the Western Pacific Ocean, and over the weekend, is forecast to pass east of both Iwo To and Chichi Jima islands. Although the center of Nida will remain ...
First metallic nanoparticles resistant to extreme heat
Nanotechnology / Nanomaterials
3 hours ago |
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A University of Pittsburgh team overcame a major hurdle plaguing the development of nanomaterials such as those that could lead to more efficient catalysts used to produce hydrogen and render car exhaust less toxic. The researchers ...
NASA captures Typhoon Nida's clouds from 2 angles
Space & Earth / Earth Sciences
39 minutes ago |
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NASA satellites capture amazing views of tropical cyclones, and the Aqua and CloudSat satellites captured a top-down look at temperatures in Typhoon Nida's clouds, and an image of what they look like from ...
Making sense of greenhouse gas accounting
23 minutes ago |
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Waste management is increasingly gaining the recognition that it deserves as a major contributor to mitigating climate change. But with at least four different methods of accounting for greenhouse gas (GHG) emissions currently ...
Hospital noise initiative reduces average peak decibel levels by 20 percent
4 hours ago |
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Patients often complain that getting a good night's sleep or a bit of peace and quiet in hospital can be difficult. But a study published in the December issue of the Journal of Clinical Nursing has shown that adopting some s ...
Holiday shopping off to mildly encouraging start
3 hours ago |
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(AP) -- After shoppers gave retailers a somewhat encouraging start to the holiday shopping season, stores now turn their attention to the online promotions known as Cyber Monday and bringing back customers ...
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