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
Researchers transform carbon dioxide into methanol
Apr 16, 2009 |
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Scientists at Singapore's Institute of Bioengineering and Nanotechnology (IBN) have succeeded in unlocking the potential of carbon dioxide - a common greenhouse gas - by converting it into a more useful product.
A dirty job but ...
Apr 13, 2009 |
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Byproducts from the electronics, fuel, chemical and defense industries can be far from benign. Toxic heavy metals like cadmium and lead can seep into our food chain and cause cancer. And if found in the soil, these dangerous ...
EPA to test air outside schools, but has largely ignoring its peer-reviewed screening tool
Apr 07, 2009 |
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After ignoring its own research for most of the last decade, the U.S. Environmental Protection Agency this spring will test the air outside dozens of schools across the nation that are close to industrial polluters.
Scientists eye risks of quantum dots
Nanotechnology / Bio & Medicine
Feb 02, 2009 |
4.3 / 5 (6) |
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Quantum dots have the potential to bring many good things into the world: efficient solar power, targeted gene and drug delivery, solid-state lighting and advances in biomedical imaging among them.
Scientists Identify Bacteria That Increase Plant Growth
Biology /
Jan 26, 2009 |
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(PhysOrg.com) -- Through work originally designed to remove contaminants from soil, scientists at the U.S. Department of Energy's Brookhaven National Laboratory and their Belgium colleagues at Hasselt University ...
Greenland ice core reveals history of pollution in the Arctic
Space & Earth / Earth Sciences
Aug 19, 2008 |
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New research, reported this week in the online early edition of the Proceedings of the National Academy of Sciences, finds that coal burning, primarily in North America and Europe, contaminated the Arctic ...
Carbon nanotubes and the environment
Nanotechnology / Bio & Medicine
May 05, 2009 |
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Carbon nanotubes have made a meteoric career in the past 15 years, even if their applications are still limited. Recent research results show that - apart from their favorable mechanical and electrical properties ...
Hidden Risks Of Modular Classrooms
Nov 18, 2009 |
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Every school day, more than 5 million students in the United States attend lessons held in modular classrooms. With new carpeting and paint, metal roofs and noisy ventilation systems, they can be a health ...
