The DOI matches its Crossref record; 15 of the 15 references it cites were found in a registry or an index.
What are heavy metals? Long-standing controversy over the scientific use of the term ‘heavy metals’ – proposal of a comprehensive definition
Abstract
The term ‘heavy metals’ is commonly used in the environmental literature to refer to metals and metalloids associated with environmental pollution, toxicity and adverse effects on biota. The term has been diversely defined, mostly in terms of density, relative atomic mass and atomic number. This diversity of definitions has raised questions about the nomenclature of these elements. The inclusion of the metalloid As and the nonmetal Se with heavy metals is also an important issue. Some people have called the term as meaningless, imprecise and poorly defined and have suggested abandoning the use of the term. The term itself may not be problematic but the careless and inconsistent use of terminology has led to a confusion about the meaning of the term. The use of the term may be continued but it should be defined in a more comprehensive and scientific way. Here, a more comprehensive definition of the term ‘heavy metals’ is suggested as ‘naturally occurring metals having atomic number (Z) greater than 20 and an elemental density greater than 5 g cm−3.’ A screening of the Periodic Table according to this definition yields 51 elements to be called ‘heavy metals.’ As and Se are excluded from heavy metals.
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Citations
Cites
Phytoremediation of heavy metals—concepts and applications
Ali, H., Khan, E., & Sajad, M. A. (2013) · Chemosphere · doi:10.1016/j.chemosphere.2013.01.075 · Cited by 3,961
Self-citationNew trends in removing heavy metals from industrial wastewater
Barakat, M. A. (2011) · Arabian Journal of Chemistry · doi:10.1016/j.arabjc.2010.07.019 · Cited by 3,094
"Heavy metals" a meaningless term? (IUPAC Technical Report)
Duffus, J. H. (2002) · Pure and Applied Chemistry · doi:10.1351/pac200274050793 · Cited by 1,364
Nieboer, E., & Richardson, D. H. S. (1980) · Environmental Pollution Series B, Chemical and Physical · doi:10.1016/0143-148x(80)90017-8 · Cited by 1,198
Bioinorganic Chemistry of Alzheimer’s Disease
Kepp, K. P. (2012) · Chemical Reviews · doi:10.1021/cr300009x · Cited by 672
A cadmium enzyme from a marine diatom
Lane, T. W., Saito, M. A., George, G. N., Pickering, I. J., Prince, R. C., & Morel, F. M. M. (2005) · Nature · doi:10.1038/435042a · Cited by 623
Fu, J., Zhou, Q., Liu, J., Liu, W., Wang, T., Zhang, Q., & Jiang, G. (2008) · Chemosphere · doi:10.1016/j.chemosphere.2007.11.065 · Cited by 551
Beasley, V. R., & Levengood, J. M. (2012) · Veterinary Toxicology · doi:10.1016/b978-0-12-385926-6.00077-6 · Cited by 271
Hawkes, S. J. (1997) · Journal of Chemical Education · doi:10.1021/ed074p1374 · Cited by 264
Chemistry: Molecules, Matter, and Change
Jones, L. F., & Atkins, P. J. (1997) · Medical Entomology and Zoology · Cited by 197
Cited by
Ali, H., Khan, E., & Ilahi, I. (2019) · Journal of Chemistry · doi:10.1155/2019/6730305 · Cited by 3,238
Self-citationZhou, Q., Yang, N., Li, Y., Ren, B., Ding, X., Bian, H., & Yao, X. (2020) · Global Ecology and Conservation · doi:10.1016/j.gecco.2020.e00925 · Cited by 694
Phytoextraction of Heavy Metals: A Promising Tool for Clean-Up of Polluted Environment?
Suman, J., Uhlik, O., Viktorova, J., & Macek, T. (2018) · Frontiers in Plant Science · doi:10.3389/fpls.2018.01476 · Cited by 553
Saxena, G., Purchase, D., Mulla, S. I., Saratale, G. D., & Bharagava, R. N. (2019) · Reviews of Environmental Contamination and Toxicology · doi:10.1007/398_2019_24 · Cited by 347
Heavy metals pollution from smelting activities: A threat to soil and groundwater
Adnan, M., Xiao, B., Ali, M. U., Xiao, P., Zhao, P., Wang, H., & Bibi, S. (2024) · Ecotoxicology and Environmental Safety · doi:10.1016/j.ecoenv.2024.116189 · Cited by 312
Metadata
- Authors
- Ali, H., & Khan, E.
- Venue
- Toxicological & Environmental Chemistry
- Publisher
- Informa UK Limited
- Published
- 2018-01-02
- Volume
- 100
- Issue
- 1
- Pages
- 6-19
- ISSN
- 0092-9867 (ISSN-L)
- 0277-2248
- 1029-0486
- OpenAlex
- W2771838486
- Cited by
- 494
- References
- 15
- FWCI
- 7.10
- Type
- journal article
- Language
- en
- Open access
- closed
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- Ali, H., & Khan, E. (2018). What are heavy metals? Long-standing controversy over the scientific use of the term ‘heavy metals’ – proposal of a comprehensive definition. Toxicological & Environmental Chemistry. https://doi.org/10.1080/02772248.2017.1413652
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Bibliographic data: Semantic Scholar, OpenAlex, Crossref.
Contains information from the Semantic Scholar Academic Graph Datasets, made available under the ODC Attribution License (ODC-BY 1.0).
Semantic Scholar’s data is described in: Kinney, R., et al. (2023). The Semantic Scholar Open Data Platform. arXiv:2301.10140.
