Heavy metals

<h2 id="definitions">Definitions</h2>
<h3>Controversial terminology</h3>
The <a href="/facts/International_Union_of_Pure_and_Applied_Chemistry/2AV6myCK">International Union of Pure and Applied Chemistry</a> (IUPAC), which standardizes nomenclature, says "the term heavy metals is both meaningless and misleading".<a class="footnote-ref" id="fnref:4" href="#fn:4">4</a> The IUPAC report focuses on the legal and toxicological implications of describing "heavy metals" as toxins when there is no scientific evidence to support a connection. The density implied by the adjective "heavy" has almost no biological consequences and pure metals are rarely the biologically active substance.<a class="footnote-ref" id="fnref:5" href="#fn:5">5</a>
This characterization has been echoed by numerous reviews.<a class="footnote-ref" id="fnref:6" href="#fn:6">6</a><a class="footnote-ref" id="fnref:7" href="#fn:7">7</a><a class="footnote-ref" id="fnref:8" href="#fn:8">8</a> The most widely used toxicology textbook, Casarett and Doull’s Toxicology<a class="footnote-ref" id="fnref:9" href="#fn:9">9</a> uses "toxic metal", not "heavy metal".<a class="footnote-ref" id="fnref:10" href="#fn:10">10</a> Nevertheless, there are scientific and science related articles which continue to use "heavy metal" as a term for toxic substances.<a class="footnote-ref" id="fnref:11" href="#fn:11">11</a><a class="footnote-ref" id="fnref:12" href="#fn:12">12</a> To be an acceptable term in scientific papers, a strict definition has been encouraged.<a class="footnote-ref" id="fnref:13" href="#fn:13">13</a>

<h3>Use outside toxicology</h3>
Even in applications other than toxicity, there no widely agreed criterion-based definition of a heavy metal. Reviews have recommended that it not be used.<a class="footnote-ref" id="fnref:14" href="#fn:14">14</a><a class="footnote-ref" id="fnref:15" href="#fn:15">15</a> Different meanings may be attached to the term, depending on the context. For example, a heavy metal may be defined on the basis of <a href="/facts/Density/92p6hh9I">density</a>,<a class="footnote-ref" id="fnref:16" href="#fn:16">16</a> the distinguishing criterion might be <a href="/facts/Atomic_number/bgAr581S">atomic number</a><a class="footnote-ref" id="fnref:17" href="#fn:17">17</a> or chemical behaviour.<a class="footnote-ref" id="fnref:18" href="#fn:18">18</a>
Density criteria range from above 3.5 g/cm3 to above 7 g/cm3.<a class="footnote-ref" id="fnref:19" href="#fn:19">19</a> Atomic weight definitions can range from greater than <a href="/facts/Sodium/eYuSPu2V">sodium</a> (atomic weight 22.98);<a class="footnote-ref" id="fnref:20" href="#fn:20">20</a> greater than 40 (excluding <a href="/facts/S-block/BbzD5jUU">s-</a> and <a href="/facts/F-block/BbzD5jUU">f-block</a> metals, hence starting with <a href="/facts/Scandium/TJRt1chg">scandium</a>);<a class="footnote-ref" id="fnref:21" href="#fn:21">21</a> or more than 200, i.e. from <a href="/facts/Mercury_(element)/WlxfoHva">mercury</a> onwards.<a class="footnote-ref" id="fnref:22" href="#fn:22">22</a> Atomic numbers are sometimes capped at 92 (<a href="/facts/Uranium/n2sGWBzU">uranium</a>).<a class="footnote-ref" id="fnref:23" href="#fn:23">23</a> Definitions based on atomic number have been criticised for including metals with low densities. For example, <a href="/facts/Rubidium/KDHSe2HM">rubidium</a> in <a href="/facts/Alkali_metals/IkWbCLk2">group (column) 1</a> of the <a href="/facts/Periodic_table/umdGIfUb">periodic table</a> has an atomic number of 37 but a density of only 1.532 g/cm3, which is below the threshold figure used by other authors.<a class="footnote-ref" id="fnref:24" href="#fn:24">24</a> The same problem may occur with definitions which are based on atomic weight.<a class="footnote-ref" id="fnref:25" href="#fn:25">25</a>

<table><tbody><tr><th colspan="20">Heat map of heavy metals in the periodic table</th></tr><tr><td></td><td><a href="/facts/Alkali_metal/IkWbCLk2">1</a></td><td><a href="/facts/Alkaline_earth_metal/Ts4U5zIe">2</a></td><td></td><td><a href="/facts/Group_3_element/q60AHJ7U">3</a></td><td><a href="/facts/Group_4_element/QGKs7lMz">4</a></td><td><a href="/facts/Group_5_element/C08aMlur">5</a></td><td><a href="/facts/Group_6_element/s8cA1Rwd">6</a></td><td><a href="/facts/Group_7_element/C1kHt0oD">7</a></td><td><a href="/facts/Group_8_element/VtbLeVpY">8</a></td><td><a href="/facts/Group_9_element/YsFjV4Ey">9</a></td><td><a href="/facts/Group_10_element/oIUwy5mC">10</a></td><td><a href="/facts/Group_11_element/phumzNJU">11</a></td><td><a href="/facts/Group_12_element/z8aB00Ih">12</a></td><td><a href="/facts/Boron_group/RXnvqnNk">13</a></td><td><a href="/facts/Carbon_group/PkWCV3Vx">14</a></td><td><a href="/facts/Pnictogen/jX4hvCkK">15</a></td><td><a href="/facts/Chalcogen/nXLGmnqL">16</a></td><td><a href="/facts/Halogen/YeFgWHeA">17</a></td><td><a href="/facts/Noble_gas/j0yHMEAE">18</a></td></tr><tr><td><a href="/facts/Period_1/bRg5LCQF">1 </a></td><td><a href="/facts/Hydrogen/BoYHjl0J">H</a></td><td colspan="17"></td><td><a href="/facts/Helium/yRul93TG">He</a></td></tr><tr><td><a href="/facts/Period_2/1ajRWfrb">2 </a></td><td><a href="/facts/Lithium/7vXX6BWA">Li</a></td><td><a href="/facts/Beryllium/dv295voP">Be</a></td><td colspan="11"></td><td><a href="/facts/Boron/Pmwgd7Mf">B</a></td><td><a href="/facts/Carbon/ukrgQexo">C</a></td><td><a href="/facts/Nitrogen/Nf1QpGDz">N</a></td><td><a href="/facts/Oxygen/acyn6o8r">O</a></td><td><a href="/facts/Fluorine/YUV0Fb8m">F</a></td><td><a href="/facts/Neon/5bF1FwGL">Ne</a></td></tr><tr><td><a href="/facts/Period_3/1BE0Nc0K">3 </a></td><td><a href="/facts/Sodium/eYuSPu2V">Na</a></td><td><a href="/facts/Magnesium/XyIhd2FG">Mg</a></td><td colspan="11"></td><td><a href="/facts/Aluminium/7wmR8jYE">Al</a></td><td><a href="/facts/Silicon/cgWx0hdr">Si</a></td><td><a href="/facts/Phosphorus/27xCeIqs">P</a></td><td><a href="/facts/Sulfur/IK0amTfM">S</a></td><td><a href="/facts/Chlorine/y27UwYBM">Cl</a></td><td><a href="/facts/Argon/QX6NRH6d">Ar</a></td></tr><tr><td><a href="/facts/Period_4/BgDFfE26">4 </a></td><td><a href="/facts/Potassium/5lcumVgo">K</a></td><td><a href="/facts/Calcium/hf252CC0">Ca</a></td><td></td><td><a href="/facts/Scandium/TJRt1chg">Sc</a></td><td><a href="/facts/Titanium/53ArnDoy">Ti</a></td><td><a href="/facts/Vanadium/UvKkKTSm">V</a></td><td><a href="/facts/Chromium/6sVk6Uu7">Cr</a></td><td><a href="/facts/Manganese/j9ELd1TL">Mn</a></td><td><a href="/facts/Iron/DkICCKIC">Fe</a></td><td><a href="/facts/Cobalt/gqhScEw4">Co</a></td><td><a href="/facts/Nickel/KwMCHYRP">Ni</a></td><td><a href="/facts/Copper/I8PEE8oX">Cu</a></td><td><a href="/facts/Zinc/80b1qgk3">Zn</a></td><td><a href="/facts/Gallium/EucevDs9">Ga</a></td><td><a href="/facts/Germanium/wtoALHGs">Ge</a></td><td><a href="/facts/Arsenic/k1c4f44D">As</a></td><td><a href="/facts/Selenium/k975NApC">Se</a></td><td><a href="/facts/Bromine/oLfj3C7D">Br</a></td><td><a href="/facts/Krypton/llkNlCke">Kr</a></td></tr><tr><td><a href="/facts/Period_5/xLJUWWDS">5 </a></td><td><a href="/facts/Rubidium/KDHSe2HM">Rb</a></td><td><a href="/facts/Strontium/ABaA5qQK">Sr</a></td><td></td><td><a href="/facts/Yttrium/BlX6rj99">Y</a></td><td><a href="/facts/Zirconium/y7gsoQFz">Zr</a></td><td><a href="/facts/Niobium/3zNI8AKp">Nb</a></td><td><a href="/facts/Molybdenum/RX6vp2bF">Mo</a></td><td><a href="/facts/Technetium/MGYWNI5d">Tc</a></td><td><a href="/facts/Ruthenium/uzCm4ufn">Ru</a></td><td><a href="/facts/Rhodium/xmBd9aFG">Rh</a></td><td><a href="/facts/Palladium/P7y0ESWf">Pd</a></td><td><a href="/facts/Silver/xXe41BGg">Ag</a></td><td><a href="/facts/Cadmium/wXkV2eIX">Cd</a></td><td><a href="/facts/Indium/zRq3stVb">In</a></td><td><a href="/facts/Tin/vxbbBgNz">Sn</a></td><td><a href="/facts/Antimony/YsA7lVgT">Sb</a></td><td><a href="/facts/Tellurium/v7QvfIvS">Te</a></td><td><a href="/facts/Iodine/JlfMecMf">I</a></td><td><a href="/facts/Xenon/9E3XR69R">Xe</a></td></tr><tr><td><a href="/facts/Period_6/9YleCXwf">6 </a></td><td><a href="/facts/Caesium/dXKN1S5k">Cs</a></td><td><a href="/facts/Barium/IkL09XHQ">Ba</a></td><td></td><td><a href="/facts/Lutetium/URlmnYG8">Lu</a></td><td><a href="/facts/Hafnium/rBNnlxDS">Hf</a></td><td><a href="/facts/Tantalum/VwaxMm33">Ta</a></td><td><a href="/facts/Tungsten/WYwbNDYX">W</a></td><td><a href="/facts/Rhenium/TzyqJYEn">Re</a></td><td><a href="/facts/Osmium/1TjXD69n">Os</a></td><td><a href="/facts/Iridium/cB4n6MbQ">Ir</a></td><td><a href="/facts/Platinum/qJC6lQf7">Pt</a></td><td><a href="/facts/Gold/1znknojp">Au</a></td><td><a href="/facts/Mercury_(element)/WlxfoHva">Hg</a></td><td><a href="/facts/Thallium/v35pGMJB">Tl</a></td><td><a href="/facts/Lead/EYljasJN">Pb</a></td><td><a href="/facts/Bismuth/75FLjkoX">Bi</a></td><td><a href="/facts/Polonium/G4rzsyjP">Po</a></td><td><a href="/facts/Astatine/AlbHPBK5">At</a></td><td><a href="/facts/Radon/0V9arWKl">Rn</a></td></tr><tr><td><a href="/facts/Period_7/H5QuVHGQ">7 </a></td><td><a href="/facts/Francium/P3Rz4gDP">Fr</a></td><td><a href="/facts/Radium/VWo5gkzn">Ra</a></td><td></td><td><a href="/facts/Lawrencium/HVw2LVlx">Lr</a></td><td><a href="/facts/Rutherfordium/44LSnv9p">Rf</a></td><td><a href="/facts/Dubnium/3CHC1lEt">Db</a></td><td><a href="/facts/Seaborgium/ejs0Ap6P">Sg</a></td><td><a href="/facts/Bohrium/epvp3GWM">Bh</a></td><td><a href="/facts/Hassium/t0bgGzwt">Hs</a></td><td><a href="/facts/Meitnerium/pKaD3sRY">Mt</a></td><td><a href="/facts/Darmstadtium/etmwTLmP">Ds</a></td><td><a href="/facts/Roentgenium/LEhvJaJQ">Rg</a></td><td><a href="/facts/Copernicium/EhgyBkg0">Cn</a></td><td><a href="/facts/Nihonium/sb09p5dv">Nh</a></td><td><a href="/facts/Flerovium/Aa7uGMuG">Fl</a></td><td><a href="/facts/Moscovium/QhSEr0H5">Mc</a></td><td><a href="/facts/Livermorium/nQc1FE6E">Lv</a></td><td><a href="/facts/Tennessine/eGCBDvEr">Ts</a></td><td><a href="/facts/Oganesson/zs5MQDjV">Og</a></td></tr><tr><td colspan="20"> </td></tr><tr><td colspan="3"></td><td></td><td><a href="/facts/Lanthanum/Uhmmy1sB">La</a></td><td><a href="/facts/Cerium/a7UjMBQ6">Ce</a></td><td><a href="/facts/Praseodymium/2lnRJ9dH">Pr</a></td><td><a href="/facts/Neodymium/GzDkTIoI">Nd</a></td><td><a href="/facts/Promethium/8xvCz9Rg">Pm</a></td><td><a href="/facts/Samarium/09K3kl93">Sm</a></td><td><a href="/facts/Europium/dqmBm1vr">Eu</a></td><td><a href="/facts/Gadolinium/eLYUeScu">Gd</a></td><td><a href="/facts/Terbium/ICF3PMED">Tb</a></td><td><a href="/facts/Dysprosium/eMev6zGS">Dy</a></td><td><a href="/facts/Holmium/C73kJVtp">Ho</a></td><td><a href="/facts/Erbium/XEJlgJcx">Er</a></td><td><a href="/facts/Thulium/G2905xhd">Tm</a></td><td><a href="/facts/Ytterbium/3lerM9uf">Yb</a></td><td></td><td></td></tr><tr><td colspan="3"></td><td></td><td><a href="/facts/Actinium/GMQtJ4Gm">Ac</a></td><td><a href="/facts/Thorium/ysdWH470">Th</a></td><td><a href="/facts/Protactinium/v87VqTPf">Pa</a></td><td><a href="/facts/Uranium/n2sGWBzU">U</a></td><td><a href="/facts/Neptunium/pwp7Yvds">Np</a></td><td><a href="/facts/Plutonium/4bUw9zH3">Pu</a></td><td><a href="/facts/Americium/rxL9Yc64">Am</a></td><td><a href="/facts/Curium/LMyWXg8l">Cm</a></td><td><a href="/facts/Berkelium/ePryEYy3">Bk</a></td><td><a href="/facts/Californium/AJVjoVut">Cf</a></td><td><a href="/facts/Einsteinium/RePoIVN9">Es</a></td><td><a href="/facts/Fermium/Us3rnvG5">Fm</a></td><td><a href="/facts/Mendelevium/bEHBu18F">Md</a></td><td><a href="/facts/Nobelium/syRkloSw">No</a></td><td></td><td></td></tr><tr><td colspan="20"> </td></tr><tr><td colspan="1"></td><td colspan="19"><table><tbody><tr><td>Number of criteria met:Number of elements:</td><td>  103 </td><td>  95 </td><td>  814 </td><td>  6–756 </td><td>  4–514 </td><td>  1–34 </td><td>  03 </td><td>  <a href="/facts/Nonmetal_(chemistry)/0oejKuzK">nonmetals</a>19 </td></tr></tbody></table></td></tr><tr><td colspan="20">This table shows the number of heavy metal criteria met by each metal, out of the ten criteria listed in this section i.e. two based on <a href="/facts/Density/92p6hh9I">density</a>, three on <a href="/facts/Atomic_weight/A3vbuz2n">atomic weight</a>, two on <a href="/facts/Atomic_number/bgAr581S">atomic number</a>, and three on chemical behaviour.<a class="footnote-ref" id="fnref:26" href="#fn:26">26</a> It illustrates the lack of agreement surrounding the concept, with the possible exception of <a href="/facts/Mercury_(element)/WlxfoHva">mercury</a>, <a href="/facts/Lead/EYljasJN">lead</a> and <a href="/facts/Bismuth/75FLjkoX">bismuth</a>.Six elements near the end of <a href="/facts/Period_(periodic_table)/WpGUFh5V">periods</a> (rows) 4 to 7 sometimes considered metalloids are treated here as metals: they are <a href="/facts/Germanium/wtoALHGs">germanium</a> (Ge), <a href="/facts/Arsenic/k1c4f44D">arsenic</a> (As), <a href="/facts/Selenium/k975NApC">selenium</a> (Se), <a href="/facts/Antimony/YsA7lVgT">antimony</a> (Sb), <a href="/facts/Tellurium/v7QvfIvS">tellurium</a> (Te), and <a href="/facts/Astatine/AlbHPBK5">astatine</a> (At).<a class="footnote-ref" id="fnref:27" href="#fn:27">27</a><a class="footnote-ref" id="fnref:28" href="#fn:28">28</a> <a href="/facts/Oganesson/zs5MQDjV">Oganesson</a> (Og) is treated as a nonmetal.<table><tbody><tr><td>Metals enclosed by a dashed line have (or, for At and Fm–Ts, are predicted to have) densities of more than 5 g/cm3.</td></tr></tbody></table></td></tr></tbody></table>
The <a href="/facts/United_States_Pharmacopeia/CyYDYG8m">United States Pharmacopeia</a> includes a test for heavy metals that involves precipitating metallic impurities as their coloured <a href="/facts/Sulfide/d8YMjLeu">sulfides</a>.<a class="footnote-ref" id="fnref:29" href="#fn:29">29</a> On the basis of this type of chemical test, the group would include the <a href="/facts/Transition_metal/0slGWoLQ">transition metals</a> and <a href="/facts/Post-transition_metal/wjp3aeGn">post-transition metals</a>.<a class="footnote-ref" id="fnref:30" href="#fn:30">30</a>
A different chemistry-based approach advocates replacing the term "heavy metal" with two groups of metals and a gray area. Class A metal ions prefer <a href="/facts/Oxygen/acyn6o8r">oxygen</a> donors; class B ions prefer <a href="/facts/Nitrogen/Nf1QpGDz">nitrogen</a> or <a href="/facts/Sulfur/IK0amTfM">sulfur</a> donors; and borderline or ambivalent ions show either class A or B characteristics, depending on the circumstances.<a class="footnote-ref" id="fnref:31" href="#fn:31">31</a> The distinction between the class A metals and the other two categories is sharp. The class A and class B terminology is analogous to the <a href="/facts/HSAB_theory/yguwscxc">"hard acid" and "soft base"</a> terminology sometimes used to refer to the behaviour of metal ions in inorganic systems.<a class="footnote-ref" id="fnref:32" href="#fn:32">32</a> The system groups the elements by 
 
 
 
 
 X
 
 m
 
 
 2
 
 
 r
 
 
 {\displaystyle X_{m}^{2}r}
 
 where 
 
 
 
 
 X
 
 m
 
 
 
 
 {\displaystyle X_{m}}
 
 is the metal ion <a href="/facts/Electronegativity/H7Vq7Uah">electronegativity</a> and 
 
 
 
 r
 
 
 {\displaystyle r}
 
 is its <a href="/facts/Ionic_radius/C3dwKrrB">ionic radius</a>. This index gauges the importance of <a href="/facts/Covalent/EzMLf3Pz">covalent</a> interactions vs <a href="/facts/Ionic_bond/R6nUJI5u">ionic</a> interactions for a given metal ion.<a class="footnote-ref" id="fnref:33" href="#fn:33">33</a> This scheme has been applied to analyze biologically active metals in sea water for example,<a class="footnote-ref" id="fnref:34" href="#fn:34">34</a> but it has not been widely adopted.<a class="footnote-ref" id="fnref:35" href="#fn:35">35</a>

<h2 id="origins-and-use-of-the-term">Origins and use of the term</h2>
The heaviness of <a href="/facts/Native_metal/gsbV9m3h">naturally occurring metals</a> such as <a href="/facts/Gold/1znknojp">gold</a>, <a href="/facts/Copper/I8PEE8oX">copper</a>, and <a href="/facts/Telluric_iron/xYgwowV9">iron</a> may have been noticed in <a href="/facts/Prehistory/52D6oKM4">prehistory</a> and, in light of their <a href="/facts/Malleable/SBJsahEk">malleability</a>, led to the first attempts to craft metal ornaments, tools, and weapons.<a class="footnote-ref" id="fnref:36" href="#fn:36">36</a>
In 1817, the German chemist <a href="/facts/Leopold_Gmelin/IHp6vhYS">Leopold Gmelin</a> divided the elements into nonmetals, light metals, and heavy metals.<a class="footnote-ref" id="fnref:37" href="#fn:37">37</a> Light metals had densities of 0.860–5.0 g/cm3; heavy metals 5.308–22.000.<a class="footnote-ref" id="fnref:38" href="#fn:38">38</a> The term heavy metal is sometimes used interchangeably with the term heavy element. For example, in discussing the history of <a href="/facts/Nuclear_chemistry/aJulAlTD">nuclear chemistry</a>, Magee<a class="footnote-ref" id="fnref:39" href="#fn:39">39</a> notes that the actinides were once thought to represent a new heavy element transition group whereas <a href="/facts/Glenn_T._Seaborg/w1a3mume">Seaborg</a> and co-workers "favoured ... a heavy metal <a href="/facts/Lanthanide/rt3XIRCl">rare-earth</a> like series ...".
The counterparts to the heavy metals, the light metals, are defined by <a href="/facts/The_Minerals%2c_Metals_%2526_Materials_Society/zTgyN9KP">The Minerals, Metals and Materials Society</a> as including "the traditional (<a href="/facts/Aluminium/7wmR8jYE">aluminium</a>, <a href="/facts/Magnesium/XyIhd2FG">magnesium</a>, <a href="/facts/Beryllium/dv295voP">beryllium</a>, <a href="/facts/Titanium/53ArnDoy">titanium</a>, <a href="/facts/Lithium/7vXX6BWA">lithium</a>, and other reactive metals) and emerging light metals (composites, laminates, etc.)"<a class="footnote-ref" id="fnref:40" href="#fn:40">40</a>

<h2 id="biological-role">Biological role</h2>
Amount of heavy metals inan average 70 kg human body<table><tbody><tr><th>Element</th><th colspan="2">Milligrams<a class="footnote-ref" id="fnref:41" href="#fn:41">41</a></th></tr><tr><td><a href="/facts/Iron/DkICCKIC">Iron</a></td><td>4000</td><td>4000 </td></tr><tr><td><a href="/facts/Zinc/80b1qgk3">Zinc</a></td><td>2500</td><td>2500 </td></tr><tr><td><a href="/facts/Lead/EYljasJN">Lead</a><a class="footnote-ref" id="fnref:42" href="#fn:42">42</a></td><td>120</td><td>120 </td></tr><tr><td><a href="/facts/Copper/I8PEE8oX">Copper</a></td><td>70</td><td>70 </td></tr><tr><td><a href="/facts/Tin/vxbbBgNz">Tin</a><a class="footnote-ref" id="fnref:43" href="#fn:43">43</a></td><td>30</td><td>30 </td></tr><tr><td><a href="/facts/Vanadium/UvKkKTSm">Vanadium</a></td><td>20</td><td>20 </td></tr><tr><td><a href="/facts/Cadmium/wXkV2eIX">Cadmium</a></td><td>20</td><td>20 </td></tr><tr><td><a href="/facts/Nickel/KwMCHYRP">Nickel</a><a class="footnote-ref" id="fnref:44" href="#fn:44">44</a></td><td>15</td><td>15 </td></tr><tr><td><a href="/facts/Selenium/k975NApC">Selenium</a><a class="footnote-ref" id="fnref:45" href="#fn:45">45</a></td><td>14</td><td>14 </td></tr><tr><td><a href="/facts/Manganese/j9ELd1TL">Manganese</a></td><td>12</td><td>12 </td></tr><tr><td>Other<a class="footnote-ref" id="fnref:46" href="#fn:46">46</a></td><td>200</td><td>200 </td></tr><tr><td>Total</td><td>7000</td><td></td></tr></tbody></table>
See also: <a href="/facts/Essential_trace_element/ACv8EG7f">Essential trace element</a>
Trace amounts of some heavy metals, mostly in period 4, are required for certain biological processes. These are <a href="/facts/Iron/DkICCKIC">iron</a> and <a href="/facts/Copper/I8PEE8oX">copper</a> (<a href="/facts/Blood/03zEulkj">oxygen</a> and <a href="/facts/Electron_transport_chain/QjcIkgeR">electron transport</a>); <a href="/facts/Cobalt/gqhScEw4">cobalt</a> (<a href="/facts/Vitamin_B12/vCk613gD">complex syntheses and cell metabolism</a>); <a href="/facts/Vanadium/UvKkKTSm">vanadium</a> and <a href="/facts/Manganese/j9ELd1TL">manganese</a> (<a href="/facts/Cofactor_(biochemistry)/AGo0PCUU">enzyme regulation</a> or functioning); <a href="/facts/Chromium/6sVk6Uu7">chromium</a> (<a href="/facts/Glucose/oUSkoLCD">glucose</a> utilisation); <a href="/facts/Nickel/KwMCHYRP">nickel</a> (<a href="/facts/Cell_growth/wbArMaJU">cell growth</a>); <a href="/facts/Arsenic/k1c4f44D">arsenic</a> (metabolic growth in some animals and possibly in humans) and <a href="/facts/Selenium/k975NApC">selenium</a> (<a href="/facts/Antioxidant/4TG4MQ83">antioxidant</a> functioning and <a href="/facts/Hormone/WFnBnINJ">hormone</a> production).<a class="footnote-ref" id="fnref:47" href="#fn:47">47</a> Periods 5 and 6 contain fewer essential heavy metals, consistent with the general pattern that heavier elements tend to be less abundant and that scarcer elements are less likely to be nutritionally essential.<a class="footnote-ref" id="fnref:48" href="#fn:48">48</a> In <a href="/facts/Period_5/xLJUWWDS">period 5</a>, <a href="/facts/Molybdenum/RX6vp2bF">molybdenum</a> is required for the <a href="/facts/Catalysis/LPBS7TQC">catalysis</a> of <a href="/facts/Redox/Pyd5RVcj">redox</a> reactions; <a href="/facts/Cadmium/wXkV2eIX">cadmium</a> is used by some marine <a href="/facts/Diatom/x2oEcP1P">diatoms</a> for the same purpose; and <a href="/facts/Tin/vxbbBgNz">tin</a> may be required for growth in a few species.<a class="footnote-ref" id="fnref:49" href="#fn:49">49</a> In <a href="/facts/Period_6/9YleCXwf">period 6</a>, <a href="/facts/Tungsten/WYwbNDYX">tungsten</a> is required by some <a href="/facts/Archaea/Adxh0aHw">archaea</a> and bacteria for <a href="/facts/Metabolic_process/WxDrm8k5">metabolic processes</a>.<a class="footnote-ref" id="fnref:50" href="#fn:50">50</a> A deficiency of any of these period 4–6 essential heavy metals may increase susceptibility to <a href="/facts/Heavy_metal_poisoning/2VRBFJVm">heavy metal poisoning</a><a class="footnote-ref" id="fnref:51" href="#fn:51">51</a> (conversely, an excess may also have <a href="/facts/Toxic_heavy_metal/2VRBFJVm">adverse biological effects</a>). 
An average 70 kg (150 lb) <a href="/facts/Composition_of_the_human_body/bbPXIH0x">human body</a> is about 0.01% heavy metals (~7 g (0.25 oz), equivalent to the weight of two dried peas, with iron at 4 g (0.14 oz), zinc at 2.5 g (0.088 oz), and lead at 0.12 g (0.0042 oz) comprising the three main constituents), 2% light metals (~1.4 kg (3.1 lb), the weight of a bottle of wine) and nearly 98% nonmetals (mostly <a href="/facts/Water/0lkXnJPK">water</a>).<a class="footnote-ref" id="fnref:52" href="#fn:52">52</a><a class="footnote-ref" id="fnref:53" href="#fn:53">53</a>
A few non-essential heavy metals have been observed to have biological effects. <a href="/facts/Gallium/EucevDs9">Gallium</a>, germanium (a metalloid), indium, and most lanthanides can stimulate metabolism, and titanium promotes growth in plants<a class="footnote-ref" id="fnref:54" href="#fn:54">54</a> (though it is not always considered a heavy metal).

<h2 id="toxicity">Toxicity</h2>
Main articles: <a href="/facts/Toxic_heavy_metal/2VRBFJVm">Toxic heavy metal</a> and <a href="/facts/Metal_toxicity/23rAhhVy">Metal toxicity</a>
Heavy metals are often assumed to be highly toxic or damaging to the environment<a class="footnote-ref" id="fnref:55" href="#fn:55">55</a> and while some are, certain others are toxic only when taken in excess or encountered in certain forms. Inhalation of certain metals, either as fine dust or most commonly as fumes, can also result in a condition called <a href="/facts/Metal_fume_fever/Hgo8q3ly">metal fume fever</a>.

<h3>Environmental heavy metals</h3>
Chromium, arsenic, cadmium, mercury, and lead have the greatest potential to cause harm on account of their extensive use, the <a href="/facts/Toxicity/qa96rs60">toxicity</a> of some of their combined or elemental forms, and their widespread distribution in the environment.<a class="footnote-ref" id="fnref:56" href="#fn:56">56</a> <a href="/facts/Hexavalent_chromium/lLgEDVPl">Hexavalent chromium</a>, for example, is highly toxic as are mercury vapour and many mercury compounds.<a class="footnote-ref" id="fnref:57" href="#fn:57">57</a> These five elements have a strong affinity for sulfur; in the human body they usually bind, via <a href="/facts/Thiol/VemKEDP9">thiol</a> groups (–SH), to <a href="/facts/Enzyme/DSI1Fh7y">enzymes</a> responsible for controlling the speed of metabolic reactions. The resulting sulfur-metal bonds inhibit the proper functioning of the enzymes involved; human health deteriorates, sometimes fatally.<a class="footnote-ref" id="fnref:58" href="#fn:58">58</a> Chromium (in its hexavalent form) and arsenic are <a href="/facts/Carcinogen/soH8Y9CE">carcinogens</a>; cadmium causes a <a href="/facts/Itai-itai_disease/BhCInjqL">degenerative bone disease</a>; and mercury and lead damage the <a href="/facts/Central_nervous_system/k8I6To97">central nervous system</a>.

Lead is the most prevalent heavy metal contaminant.<a class="footnote-ref" id="fnref:59" href="#fn:59">59</a> Levels in the aquatic environments of industrialised societies have been estimated to be two to three times those of pre-industrial levels.<a class="footnote-ref" id="fnref:60" href="#fn:60">60</a> As a component of <a href="/facts/Tetraethyl_lead/M33pHTTX">tetraethyl lead</a>, (CH3CH2)4Pb, it was used extensively in <a href="/facts/Gasoline/lcnxq5BS">gasoline</a> from the 1930s until the 1970s.<a class="footnote-ref" id="fnref:61" href="#fn:61">61</a> Although the use of leaded gasoline was largely phased out in North America by 1996, soils next to roads built before this time retain high lead concentrations.<a class="footnote-ref" id="fnref:62" href="#fn:62">62</a> Later research demonstrated a statistically significant correlation between the usage rate of leaded gasoline and violent crime in the United States; taking into account a 22-year time lag (for the average age of violent criminals), the violent crime curve virtually tracked the lead exposure curve.<a class="footnote-ref" id="fnref:63" href="#fn:63">63</a>
Other heavy metals noted for their potentially hazardous nature, usually as toxic environmental pollutants, include manganese (central nervous system damage);<a class="footnote-ref" id="fnref:64" href="#fn:64">64</a> cobalt and <a href="/facts/Nickel/KwMCHYRP">nickel</a> (carcinogens);<a class="footnote-ref" id="fnref:65" href="#fn:65">65</a> copper,<a class="footnote-ref" id="fnref:66" href="#fn:66">66</a> zinc,<a class="footnote-ref" id="fnref:67" href="#fn:67">67</a> selenium<a class="footnote-ref" id="fnref:68" href="#fn:68">68</a> and <a href="/facts/Silver/xXe41BGg">silver</a><a class="footnote-ref" id="fnref:69" href="#fn:69">69</a> (<a href="/facts/Endocrine_system/PDvN5cpj">endocrine</a> disruption, <a href="/facts/Congenital_disorder/ESfzQhTx">congenital disorders</a>, or general toxic effects in fish, plants, birds, or other aquatic organisms); tin, as <a href="/facts/Organotin/B4aDa9Lq">organotin</a> (central nervous system damage);<a class="footnote-ref" id="fnref:70" href="#fn:70">70</a> antimony (a suspected carcinogen);<a class="footnote-ref" id="fnref:71" href="#fn:71">71</a> and <a href="/facts/Thallium/v35pGMJB">thallium</a> (central nervous system damage).<a class="footnote-ref" id="fnref:72" href="#fn:72">72</a><a class="footnote-ref" id="fnref:73" href="#fn:73">73</a>

<h3>Other heavy metals</h3>
A few other non-essential heavy metals have one or more toxic forms. Kidney failure and fatalities have been recorded arising from the ingestion of germanium dietary supplements (~15 to 300 g in total consumed over a period of two months to three years).<a class="footnote-ref" id="fnref:74" href="#fn:74">74</a> Exposure to <a href="/facts/Osmium_tetroxide/cxmYVnFK">osmium tetroxide</a> (OsO4) may cause permanent eye damage and can lead to respiratory failure<a class="footnote-ref" id="fnref:75" href="#fn:75">75</a> and death.<a class="footnote-ref" id="fnref:76" href="#fn:76">76</a> Indium salts are toxic if more than few milligrams are ingested and will affect the kidneys, liver, and heart.<a class="footnote-ref" id="fnref:77" href="#fn:77">77</a> <a href="/facts/Cisplatin/eXLc7Fzw">Cisplatin</a> (PtCl2(NH3)2), an important drug used to <a href="/facts/Chemotherapy/fWTLbaUT">kill cancer cells</a>, is also a kidney and nerve poison.<a class="footnote-ref" id="fnref:78" href="#fn:78">78</a> <a href="/facts/Bismuth/75FLjkoX">Bismuth</a> compounds can cause liver damage if taken in excess; insoluble uranium compounds, as well as the dangerous <a href="/facts/Radiation_damage/xTPC6Xg3">radiation</a> they emit, can cause permanent kidney damage.<a class="footnote-ref" id="fnref:79" href="#fn:79">79</a>

<h3>Exposure sources</h3>
See also: <a href="/facts/Cement/VfDMkk12">Cement § Heavy metal emissions in the air</a>
Heavy metals can degrade air, water, and <a href="/facts/Soil_quality/2mDaaCxb">soil quality</a>, and subsequently cause health issues in plants, animals, and people, when they become concentrated as a result of industrial activities.<a class="footnote-ref" id="fnref:80" href="#fn:80">80</a><a class="footnote-ref" id="fnref:81" href="#fn:81">81</a> Common sources of heavy metals in this context include vehicle emissions;<a class="footnote-ref" id="fnref:82" href="#fn:82">82</a> motor oil;<a class="footnote-ref" id="fnref:83" href="#fn:83">83</a> fertilisers;<a class="footnote-ref" id="fnref:84" href="#fn:84">84</a> glassworking;<a class="footnote-ref" id="fnref:85" href="#fn:85">85</a> incinerators;<a class="footnote-ref" id="fnref:86" href="#fn:86">86</a> <a href="/facts/Treated_wood/eLLDnkbE">treated timber</a>;<a class="footnote-ref" id="fnref:87" href="#fn:87">87</a> <a href="/facts/Pipe_(fluid_conveyance)/dgX5uQjj">aging water supply infrastructure</a>;<a class="footnote-ref" id="fnref:88" href="#fn:88">88</a> and <a href="/facts/Microplastics/HzH0eKP5">microplastics</a> floating in the world's oceans.<a class="footnote-ref" id="fnref:89" href="#fn:89">89</a> Recent examples of heavy metal contamination and health risks include the occurrence of <a href="/facts/Minamata_disease/K2mM5Eex">Minamata disease</a>, in Japan (1932–1968; lawsuits ongoing as of 2016);<a class="footnote-ref" id="fnref:90" href="#fn:90">90</a> the <a href="/facts/Bento_Rodrigues_dam_disaster/65dAkDuM">Bento Rodrigues dam disaster</a> in Brazil,<a class="footnote-ref" id="fnref:91" href="#fn:91">91</a> high levels of lead in drinking water supplied to the residents of <a href="/facts/Flint_water_crisis/w5AgWJga">Flint</a>, Michigan, in the north-east of the United States<a class="footnote-ref" id="fnref:92" href="#fn:92">92</a> and <a href="/facts/2015_Hong_Kong_heavy_metal_in_drinking_water_incidents/QHn0lKbW">2015 Hong Kong heavy metal in drinking water incidents</a>.

<h2 id="formation-abundance-occurrence-and-extraction">Formation, abundance, occurrence, and extraction</h2>
See also: <a href="/facts/Nucleosynthesis/F9MIeADF">Nucleosynthesis</a> and <a href="/facts/Abundance_of_the_chemical_elements/CE9WehBl">Abundance of the chemical elements</a>
<table><tbody><tr><td colspan="20"> </td></tr><tr><th colspan="20">Heavy metals in the Earth's crust:</th></tr><tr><td colspan="20">abundance and main occurrence or source<a class="footnote-ref" id="fnref:93" href="#fn:93">93</a></td></tr><tr><td></td><td><a href="/facts/Alkali_metal/IkWbCLk2">1</a></td><td><a href="/facts/Alkaline_earth_metal/Ts4U5zIe">2</a></td><td></td><td><a href="/facts/Group_3_element/q60AHJ7U">3</a></td><td><a href="/facts/Group_4_element/QGKs7lMz">4</a></td><td><a href="/facts/Group_5_element/C08aMlur">5</a></td><td><a href="/facts/Group_6_element/s8cA1Rwd">6</a></td><td><a href="/facts/Group_7_element/C1kHt0oD">7</a></td><td><a href="/facts/Group_8_element/VtbLeVpY">8</a></td><td><a href="/facts/Group_9_element/YsFjV4Ey">9</a></td><td><a href="/facts/Group_10_element/oIUwy5mC">10</a></td><td><a href="/facts/Group_11_element/phumzNJU">11</a></td><td><a href="/facts/Group_12_element/z8aB00Ih">12</a></td><td><a href="/facts/Boron_group/RXnvqnNk">13</a></td><td><a href="/facts/Carbon_group/PkWCV3Vx">14</a></td><td><a href="/facts/Pnictogen/jX4hvCkK">15</a></td><td><a href="/facts/Chalcogen/nXLGmnqL">16</a></td><td><a href="/facts/Halogen/YeFgWHeA">17</a></td><td><a href="/facts/Noble_gas/j0yHMEAE">18</a></td></tr><tr><td><a href="/facts/Period_1/bRg5LCQF">1 </a></td><td><a href="/facts/Hydrogen/BoYHjl0J">H</a></td><td colspan="17"></td><td><a href="/facts/Helium/yRul93TG">He</a></td></tr><tr><td><a href="/facts/Period_2/1ajRWfrb">2 </a></td><td><a href="/facts/Lithium/7vXX6BWA">Li</a></td><td><a href="/facts/Beryllium/dv295voP">Be</a></td><td colspan="11"></td><td><a href="/facts/Boron/Pmwgd7Mf">B</a></td><td><a href="/facts/Carbon/ukrgQexo">C</a></td><td><a href="/facts/Nitrogen/Nf1QpGDz">N</a></td><td><a href="/facts/Oxygen/acyn6o8r">O</a></td><td><a href="/facts/Fluorine/YUV0Fb8m">F</a></td><td><a href="/facts/Neon/5bF1FwGL">Ne</a></td></tr><tr><td><a href="/facts/Period_3/1BE0Nc0K">3 </a></td><td><a href="/facts/Sodium/eYuSPu2V">Na</a></td><td><a href="/facts/Magnesium/XyIhd2FG">Mg</a></td><td colspan="3"></td><td colspan="4"></td><td colspan="4"></td><td><a href="/facts/Aluminium/7wmR8jYE">Al</a></td><td><a href="/facts/Silicon/cgWx0hdr">Si</a></td><td><a href="/facts/Phosphorus/27xCeIqs">P</a></td><td><a href="/facts/Sulfur/IK0amTfM">S</a></td><td><a href="/facts/Chlorine/y27UwYBM">Cl</a></td><td><a href="/facts/Argon/QX6NRH6d">Ar</a></td></tr><tr><td><a href="/facts/Period_4/BgDFfE26">4 </a></td><td><a href="/facts/Potassium/5lcumVgo">K</a></td><td><a href="/facts/Calcium/hf252CC0">Ca</a></td><td></td><td><a href="/facts/Scandium/TJRt1chg">Sc</a></td><td><a href="/facts/Titanium/53ArnDoy">Ti</a></td><td><a href="/facts/Vanadium/UvKkKTSm">V</a></td><td><a href="/facts/Chromium/6sVk6Uu7">Cr</a></td><td><a href="/facts/Manganese/j9ELd1TL">Mn</a></td><td><a href="/facts/Iron/DkICCKIC">Fe</a></td><td><a href="/facts/Cobalt/gqhScEw4">Co</a></td><td><a href="/facts/Nickel/KwMCHYRP">Ni</a></td><td><a href="/facts/Copper/I8PEE8oX">Cu</a></td><td><a href="/facts/Zinc/80b1qgk3">Zn</a></td><td><a href="/facts/Gallium/EucevDs9">Ga</a></td><td><a href="/facts/Germanium/wtoALHGs">Ge</a></td><td><a href="/facts/Arsenic/k1c4f44D">As</a></td><td><a href="/facts/Selenium/k975NApC">Se</a></td><td><a href="/facts/Bromine/oLfj3C7D">Br</a></td><td><a href="/facts/Krypton/llkNlCke">Kr</a></td></tr><tr><td><a href="/facts/Period_5/xLJUWWDS">5 </a></td><td><a href="/facts/Rubidium/KDHSe2HM">Rb</a></td><td><a href="/facts/Strontium/ABaA5qQK">Sr</a></td><td></td><td><a href="/facts/Yttrium/BlX6rj99">Y</a></td><td><a href="/facts/Zirconium/y7gsoQFz">Zr</a></td><td><a href="/facts/Niobium/3zNI8AKp">Nb</a></td><td><a href="/facts/Molybdenum/RX6vp2bF">Mo</a></td><td></td><td><a href="/facts/Ruthenium/uzCm4ufn">Ru</a></td><td><a href="/facts/Rhodium/xmBd9aFG">Rh</a></td><td><a href="/facts/Palladium/P7y0ESWf">Pd</a></td><td><a href="/facts/Silver/xXe41BGg">Ag</a></td><td><a href="/facts/Cadmium/wXkV2eIX">Cd</a></td><td><a href="/facts/Indium/zRq3stVb">In</a></td><td><a href="/facts/Tin/vxbbBgNz">Sn</a></td><td><a href="/facts/Antimony/YsA7lVgT">Sb</a></td><td><a href="/facts/Tellurium/v7QvfIvS">Te</a></td><td><a href="/facts/Iodine/JlfMecMf"> I </a></td><td><a href="/facts/Xenon/9E3XR69R">Xe</a></td></tr><tr><td><a href="/facts/Period_6/9YleCXwf">6 </a></td><td><a href="/facts/Caesium/dXKN1S5k">Cs</a></td><td><a href="/facts/Barium/IkL09XHQ">Ba</a></td><td></td><td><a href="/facts/Lutetium/URlmnYG8">Lu</a></td><td><a href="/facts/Hafnium/rBNnlxDS">Hf</a></td><td><a href="/facts/Tantalum/VwaxMm33">Ta</a></td><td><a href="/facts/Tungsten/WYwbNDYX">W</a></td><td><a href="/facts/Rhenium/TzyqJYEn">Re</a></td><td><a href="/facts/Osmium/1TjXD69n">Os</a></td><td><a href="/facts/Iridium/cB4n6MbQ">Ir</a></td><td><a href="/facts/Platinum/qJC6lQf7">Pt</a></td><td><a href="/facts/Gold/1znknojp">Au</a></td><td><a href="/facts/Mercury_(element)/WlxfoHva">Hg</a></td><td><a href="/facts/Thallium/v35pGMJB">Tl</a></td><td><a href="/facts/Lead/EYljasJN">Pb</a></td><td><a href="/facts/Bismuth/75FLjkoX">Bi</a></td><td></td><td></td><td></td></tr><tr><td><a href="/facts/Period_7/H5QuVHGQ">7 </a></td><td></td><td></td><td></td><td colspan="4"></td><td colspan="4"></td><td></td><td colspan="5"></td><td colspan="1"></td></tr><tr><td colspan="8"></td><td colspan="10"></td><td colspan="1"></td></tr><tr><td colspan="3"></td><td></td><td><a href="/facts/Lanthanum/Uhmmy1sB">La</a></td><td><a href="/facts/Cerium/a7UjMBQ6">Ce</a></td><td><a href="/facts/Praseodymium/2lnRJ9dH">Pr</a></td><td><a href="/facts/Neodymium/GzDkTIoI">Nd</a></td><td></td><td><a href="/facts/Samarium/09K3kl93">Sm</a></td><td><a href="/facts/Europium/dqmBm1vr">Eu</a></td><td><a href="/facts/Gadolinium/eLYUeScu">Gd</a></td><td><a href="/facts/Terbium/ICF3PMED">Tb</a></td><td><a href="/facts/Dysprosium/eMev6zGS">Dy</a></td><td><a href="/facts/Holmium/C73kJVtp">Ho</a></td><td><a href="/facts/Erbium/XEJlgJcx">Er</a></td><td><a href="/facts/Thulium/G2905xhd">Tm</a></td><td><a href="/facts/Ytterbium/3lerM9uf">Yb</a></td><td></td><td></td></tr><tr><td colspan="3"></td><td></td><td></td><td><a href="/facts/Thorium/ysdWH470">Th</a></td><td></td><td><a href="/facts/Uranium/n2sGWBzU">U</a></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td colspan="20"> </td></tr><tr><td></td><td colspan="10">   Most abundant (56,300 ppm by weight)</td><td colspan="9">   Rare (0.01–0.99 ppm)</td></tr><tr><td></td><td colspan="10">   Abundant (100–999 ppm)</td><td colspan="9">   Very rare (0.0001–0.0099 ppm)</td></tr><tr><td></td><td colspan="10">   Uncommon (1–99 ppm)</td><td></td></tr><tr><td> </td></tr><tr><td colspan="20">Heavy metals left of the dividing line occur (or are sourced) mainly as <a href="/facts/Goldschmidt_classification/8p9CWrpe">lithophiles</a>; those to the right, as <a href="/facts/Goldschmidt_classification/8p9CWrpe">chalcophiles</a> except gold (a <a href="/facts/Goldschmidt_classification/8p9CWrpe">siderophile</a>) and tin (a lithophile).</td></tr></tbody></table>
Heavy metals up to the <a href="/facts/Iron_peak/GYAe3weY">vicinity of iron</a> (in the periodic table) are largely made via <a href="/facts/Stellar_nucleosynthesis/qEQJdJe6">stellar nucleosynthesis</a>. In this process, lighter elements from hydrogen to <a href="/facts/Silicon/cgWx0hdr">silicon</a> undergo successive <a href="/facts/Nuclear_fusion/hP0gLDqj">fusion</a> reactions inside stars, releasing light and heat and forming heavier elements with higher atomic numbers.<a class="footnote-ref" id="fnref:94" href="#fn:94">94</a>
Heavier heavy metals are not usually formed this way since fusion reactions involving such nuclei would consume rather than release energy.<a class="footnote-ref" id="fnref:95" href="#fn:95">95</a> Rather, they are largely synthesised (from elements with a lower atomic number) by <a href="/facts/Neutron_capture/elsFpM12">neutron capture</a>, with the two main modes of this repetitive capture being the <a href="/facts/S-process/31HVkqkI">s-process</a> and the <a href="/facts/R-process/wEDL01yc">r-process</a>. In the s-process ("s" stands for "slow"), singular captures are separated by years or decades, allowing the less stable nuclei to <a href="/facts/Beta_decay/vxTBlckp">beta decay</a>,<a class="footnote-ref" id="fnref:96" href="#fn:96">96</a> while in the r-process ("rapid"), captures happen faster than nuclei can decay. Therefore, the s-process takes a more or less clear path: for example, stable cadmium-110 nuclei are successively bombarded by free neutrons inside a star until they form cadmium-115 nuclei which are unstable and decay to form indium-115 (which is nearly stable, with a half-life 30,000 times the age of the universe). These nuclei capture neutrons and form indium-116, which is unstable, and decays to form tin-116, and so on.<a class="footnote-ref" id="fnref:97" href="#fn:97">97</a><a class="footnote-ref" id="fnref:98" href="#fn:98">98</a><a class="footnote-ref" id="fnref:99" href="#fn:99">99</a> In contrast, there is no such path in the r-process. The s-process stops at bismuth due to the short half-lives of the next two elements, polonium and astatine, which decay to bismuth or lead. The r-process is so fast it can skip this zone of instability and go on to create heavier elements such as <a href="/facts/Thorium/ysdWH470">thorium</a> and uranium.<a class="footnote-ref" id="fnref:100" href="#fn:100">100</a>
Heavy metals condense in planets as a result of stellar evolution and destruction processes. Stars lose much of their mass when it is <a href="/facts/Stellar_mass_loss/61jfD9bm">ejected</a> late in their lifetimes, and sometimes thereafter as a result of a <a href="/facts/Neutron_star/4enfoxBA">neutron star</a> merger,<a class="footnote-ref" id="fnref:101" href="#fn:101">101</a><a class="footnote-ref" id="fnref:102" href="#fn:102">102</a> thereby increasing the abundance of elements heavier than helium in the <a href="/facts/Interstellar_medium/mokU0WEz">interstellar medium</a>. When gravitational attraction causes this matter to coalesce and collapse, <a href="/facts/Nebular_hypothesis/IT3D6MpE">new stars and planets are formed</a>.<a class="footnote-ref" id="fnref:103" href="#fn:103">103</a>
The Earth's crust is made of approximately 5% of heavy metals by weight, with iron comprising 95% of this quantity. Light metals (~20%) and nonmetals (~75%) make up the other 95% of the crust.<a class="footnote-ref" id="fnref:104" href="#fn:104">104</a> Despite their overall scarcity, heavy metals can become concentrated in economically extractable quantities as a result of <a href="/facts/Mountain_formation/zVjPULmN">mountain building</a>, <a href="/facts/Erosion/gaGJXy0W">erosion</a>, or other <a href="/facts/Geomorphology/MDf2I2h5">geological processes</a>.<a class="footnote-ref" id="fnref:105" href="#fn:105">105</a>
Heavy metals are found primarily as <a href="/facts/Goldschmidt_classification/8p9CWrpe">lithophiles</a> (rock-loving) or <a href="/facts/Goldschmidt_classification/8p9CWrpe">chalcophiles</a> (ore-loving). Lithophile heavy metals are mainly f-block elements and the more reactive of the <a href="/facts/D-block/BbzD5jUU">d-block</a> elements. They have a strong affinity for oxygen and mostly exist as relatively low density <a href="/facts/Silicate_minerals/WclrQW2I">silicate minerals</a>.<a class="footnote-ref" id="fnref:106" href="#fn:106">106</a> Chalcophile heavy metals are mainly the less reactive d-block elements, and period 4–6 <a href="/facts/P-block/BbzD5jUU">p-block</a> metals and metalloids. They are usually found in (insoluble) <a href="/facts/Sulfide_minerals/f8rxJpCW">sulfide minerals</a>. Being denser than the lithophiles, hence sinking lower into the crust at the time of its solidification, the chalcophiles tend to be less abundant than the lithophiles.<a class="footnote-ref" id="fnref:107" href="#fn:107">107</a>
In contrast, gold is a <a href="/facts/Goldschmidt_classification/8p9CWrpe">siderophile</a>, or iron-loving element. It does not readily form compounds with either oxygen or sulfur.<a class="footnote-ref" id="fnref:108" href="#fn:108">108</a> At the time of the <a href="/facts/Formation_of_the_Earth/HLLmDfj0">Earth's formation</a>, and as the most <a href="/facts/Noble_metal/Pe9EKIvU">noble</a> (inert) of metals, gold sank into the <a href="/facts/Structure_of_the_Earth/678dYXU7">core</a> due to its tendency to form high-density metallic alloys. Consequently, it is a relatively rare metal.<a class="footnote-ref" id="fnref:109" href="#fn:109">109</a> Some other (less) noble heavy metals—molybdenum, <a href="/facts/Rhenium/TzyqJYEn">rhenium</a>, the <a href="/facts/Platinum_group_metal/pbDgst54">platinum group metals</a> (<a href="/facts/Ruthenium/uzCm4ufn">ruthenium</a>, rhodium, <a href="/facts/Palladium/P7y0ESWf">palladium</a>, osmium, <a href="/facts/Iridium/cB4n6MbQ">iridium</a>, and platinum), germanium, and tin—can be counted as siderophiles but only in terms of their primary occurrence in the Earth (core, <a href="/facts/Structure_of_the_Earth/678dYXU7">mantle</a> and crust), rather the crust. These metals otherwise occur in the crust, in small quantities, chiefly as chalcophiles (less so in their <a href="/facts/Native_metal/gsbV9m3h">native form</a>).<a class="footnote-ref" id="fnref:110" href="#fn:110">110</a><a class="footnote-ref" id="fnref:111" href="#fn:111">111</a>
Concentrations of heavy metals below the crust are generally higher, with most being found in the largely iron-silicon-nickel core. <a href="/facts/Platinum/qJC6lQf7">Platinum</a>, for example, comprises approximately 1 part per billion of the crust whereas its concentration in the core is thought to be nearly 6,000 times higher.<a class="footnote-ref" id="fnref:112" href="#fn:112">112</a><a class="footnote-ref" id="fnref:113" href="#fn:113">113</a> Recent speculation suggests that uranium (and thorium) in the core may generate a substantial amount of the heat that drives <a href="/facts/Plate_tectonics/RtRG5lY4">plate tectonics</a> and (ultimately) sustains the <a href="/facts/Earth%2527s_magnetic_field/73G36wmx">Earth's magnetic field</a>.<a class="footnote-ref" id="fnref:114" href="#fn:114">114</a><a class="footnote-ref" id="fnref:115" href="#fn:115">115</a>
Broadly speaking, and with some exceptions, lithophile heavy metals can be extracted from their ores by <a href="/facts/Electrowinning/XYkUqWVM">electrical</a> or <a href="/facts/Chemical_reduction/Pyd5RVcj">chemical treatments</a>, while chalcophile heavy metals are obtained by <a href="/facts/Roasting_(metallurgy)/kvlzMoeg">roasting</a> their sulphide ores to yield the corresponding oxides, and then heating these to obtain the raw metals.<a class="footnote-ref" id="fnref:116" href="#fn:116">116</a><a class="footnote-ref" id="fnref:117" href="#fn:117">117</a> Radium occurs in quantities too small to be economically mined and is instead obtained from spent <a href="/facts/Nuclear_fuel/8RhAomlJ">nuclear fuels</a>.<a class="footnote-ref" id="fnref:118" href="#fn:118">118</a> The chalcophile platinum group metals (PGM) mainly occur in small (mixed) quantities with other chalcophile ores. The ores involved need to be <a href="/facts/Smelting/Ghdvhlga">smelted</a>, roasted, and then <a href="/facts/Leaching_(metallurgy)/lkF9x75r">leached</a> with <a href="/facts/Sulfuric_acid/Wom6fymJ">sulfuric acid</a> to produce a residue of PGM. This is chemically refined to obtain the individual metals in their pure forms.<a class="footnote-ref" id="fnref:119" href="#fn:119">119</a> Compared to other metals, PGM are expensive due to their scarcity<a class="footnote-ref" id="fnref:120" href="#fn:120">120</a> and high production costs.<a class="footnote-ref" id="fnref:121" href="#fn:121">121</a>
Gold, a siderophile, is most commonly recovered by dissolving the ores in which it is found in a <a href="/facts/Gold_cyanidation/cfLm9oBQ">cyanide solution</a>.<a class="footnote-ref" id="fnref:122" href="#fn:122">122</a> The gold forms a dicyanoaurate(I), for example: 2 Au + <a href="/facts/Water/0lkXnJPK">H2O</a> +½ O2 + 4 <a href="/facts/Potassium_cyanide/xcoXn4I8">KCN</a> → 2 K[Au(CN)2] + 2 <a href="/facts/Potassium_hydroxide/NBhPBuXc">KOH</a>. Zinc is added to the mix and, being more <a href="/facts/Reactivity_series/kbv5QP1Y">reactive</a> than gold, displaces the gold: 2 K[Au(CN)2] + Zn → K2[Zn(CN)4] + 2 Au. The gold precipitates out of solution as a sludge, and is filtered off and melted.<a class="footnote-ref" id="fnref:123" href="#fn:123">123</a>

<h2 id="uses">Uses</h2>
Some common uses of heavy metals depend on the general characteristics of metals such as <a href="/facts/Electrical_conductivity/akyCKvMy">electrical conductivity</a> and <a href="/facts/Reflectivity/TT4sBwIw">reflectivity</a> or the general characteristics of heavy metals such as density, strength, and durability. Other uses depend on the characteristics of the specific element, such as their biological role as nutrients or poisons or some other specific atomic properties. Examples of such atomic properties include: partly filled <a href="/facts/D-orbital/tKhgl6mL">d-</a> or <a href="/facts/F-orbital/tKhgl6mL">f- orbitals</a> (in many of the transition, lanthanide, and actinide heavy metals) that enable the formation of coloured compounds;<a class="footnote-ref" id="fnref:124" href="#fn:124">124</a> the capacity of heavy metal ions (such as platinum,<a class="footnote-ref" id="fnref:125" href="#fn:125">125</a> cerium<a class="footnote-ref" id="fnref:126" href="#fn:126">126</a> or bismuth<a class="footnote-ref" id="fnref:127" href="#fn:127">127</a>) to exist in different <a href="/facts/Oxidation_state/W53W6s6V">oxidation states</a> and are used in catalysts;<a class="footnote-ref" id="fnref:128" href="#fn:128">128</a> strong <a href="/facts/Exchange_interactions/orogl7qP">exchange interactions</a> in 3d or 4f orbitals (in iron, cobalt, and nickel, or the lanthanide heavy metals) that give rise to magnetic effects;<a class="footnote-ref" id="fnref:129" href="#fn:129">129</a> and high atomic numbers and <a href="/facts/Electron_density/L5yDsk6j">electron densities</a> that underpin their nuclear science applications.<a class="footnote-ref" id="fnref:130" href="#fn:130">130</a> Typical uses of heavy metals can be broadly grouped into the following categories.<a class="footnote-ref" id="fnref:131" href="#fn:131">131</a>

<h3>Weight- or density-based</h3>

Some uses of heavy metals, including in sport, <a href="/facts/Mechanical_engineering/cbId4fye">mechanical engineering</a>, <a href="/facts/Artillery/GLpMYG9o">military ordnance</a>, and <a href="/facts/Nuclear_science/fzQbt1aF">nuclear science</a>, take advantage of their relatively high densities. In <a href="/facts/Underwater_diving/yhjLjF1H">underwater diving</a>, lead is used as a <a href="/facts/Ballast/hF7xWfRg">ballast</a>;<a class="footnote-ref" id="fnref:132" href="#fn:132">132</a> in <a href="/facts/Handicapping/c1ngyrRC">handicap horse racing</a> each horse must carry a specified lead weight, based on factors including past performance, so as to equalize the chances of the various competitors.<a class="footnote-ref" id="fnref:133" href="#fn:133">133</a> In <a href="/facts/Golf/k8jn7q42">golf</a>, tungsten, <a href="/facts/Brass/pe8EHk6x">brass</a>, or copper inserts in <a href="/facts/Fairway_(golf)/8kuMFVyx">fairway</a> <a href="/facts/Golf_club/e10LtRMx">clubs and irons</a> lower the centre of gravity of the club making it easier to get the ball into the air;<a class="footnote-ref" id="fnref:134" href="#fn:134">134</a> and golf balls with tungsten cores are claimed to have better flight characteristics.<a class="footnote-ref" id="fnref:135" href="#fn:135">135</a> In <a href="/facts/Fly_fishing/dCKhBjoE">fly fishing</a>, sinking fly lines have a <a href="/facts/Polyvinyl_chloride/9VkegJvr">PVC</a> coating embedded with tungsten powder, so that they sink at the required rate.<a class="footnote-ref" id="fnref:136" href="#fn:136">136</a> In <a href="/facts/Track_and_field/UNg97aPX">track and field</a> sport, <a href="/facts/Steel/aN6qWo4H">steel</a> balls used in the <a href="/facts/Hammer_throw/hPyBRIxp">hammer throw</a> and <a href="/facts/Shot_put/pPQ1j0sl">shot put</a> events are filled with lead in order to attain the minimum weight required under international rules.<a class="footnote-ref" id="fnref:137" href="#fn:137">137</a> Tungsten was used in hammer throw balls at least up to 1980; the minimum size of the ball was increased in 1981 to eliminate the need for what was, at that time, an expensive metal (triple the cost of other hammers) not generally available in all countries.<a class="footnote-ref" id="fnref:138" href="#fn:138">138</a> Tungsten hammers were so dense that they penetrated too deeply into the turf.<a class="footnote-ref" id="fnref:139" href="#fn:139">139</a>

Heavy metals are used for ballast in boats,<a class="footnote-ref" id="fnref:140" href="#fn:140">140</a> aeroplanes,<a class="footnote-ref" id="fnref:141" href="#fn:141">141</a> and motor vehicles;<a class="footnote-ref" id="fnref:142" href="#fn:142">142</a> or in <a href="/facts/Tire_balance/FMHFRbV5">balance weights on wheels</a> and <a href="/facts/Crankshaft/oYCe9nB3">crankshafts</a>,<a class="footnote-ref" id="fnref:143" href="#fn:143">143</a> <a href="/facts/Gyroscope/UjXGsfMq">gyroscopes</a>, and <a href="/facts/Propeller/0IN0JKXC">propellers</a>,<a class="footnote-ref" id="fnref:144" href="#fn:144">144</a> and <a href="/facts/Centrifugal_clutch/yffjaKse">centrifugal clutches</a>,<a class="footnote-ref" id="fnref:145" href="#fn:145">145</a> in situations requiring maximum weight in minimum space (for example in <a href="/facts/Movement_(clockwork)/G7CES9vo">watch movements</a>).<a class="footnote-ref" id="fnref:146" href="#fn:146">146</a>
In military ordnance, tungsten or uranium is used in <a href="/facts/Chobham_armour/C1ve0lva">armour plating</a><a class="footnote-ref" id="fnref:147" href="#fn:147">147</a> and <a href="/facts/Kinetic_energy_penetrator/RHE3NJqY">armour piercing projectiles</a>,<a class="footnote-ref" id="fnref:148" href="#fn:148">148</a> as well as in <a href="/facts/Nuclear_weapon_design/gw0LEc74">nuclear weapons</a> to increase efficiency (by <a href="/facts/Neutron_reflector/yDkgmcrE">reflecting neutrons</a> and momentarily delaying the expansion of reacting materials).<a class="footnote-ref" id="fnref:149" href="#fn:149">149</a> In the 1970s, <a href="/facts/Tantalum/VwaxMm33">tantalum</a> was found to be more effective than copper in <a href="/facts/Shaped_charge/bJGUyrWM">shaped charge</a> and <a href="/facts/Explosively_formed_penetrator/IYo1L0LL">explosively formed anti-armour weapons</a> on account of its higher density, allowing greater force concentration, and better deformability.<a class="footnote-ref" id="fnref:150" href="#fn:150">150</a> Less-<a href="/facts/Toxic_heavy_metal/2VRBFJVm">toxic heavy metals</a>, such as copper, tin, tungsten, and bismuth, and probably manganese (as well as <a href="/facts/Boron/Pmwgd7Mf">boron</a>, a metalloid), have replaced lead and antimony in the <a href="/facts/Green_bullets/HmCVH62C">green bullets</a> used by some armies and in some recreational shooting munitions.<a class="footnote-ref" id="fnref:151" href="#fn:151">151</a> Doubts have been raised about the safety (or <a href="/facts/Environmentally_friendly/cc9zhfHV">green credentials</a>) of tungsten.<a class="footnote-ref" id="fnref:152" href="#fn:152">152</a>

<h3>Biological and chemical</h3>
The <a href="/facts/Biocide/VwIWkeJE">biocidal</a> effects of <a href="/facts/Oligodynamic_effect/uKE1lupq">some heavy metals</a> have been known since antiquity.<a class="footnote-ref" id="fnref:153" href="#fn:153">153</a> Platinum, osmium, copper, ruthenium, and other heavy metals, including arsenic, are used in anti-cancer treatments, or have shown potential.<a class="footnote-ref" id="fnref:154" href="#fn:154">154</a> Antimony (anti-protozoal), bismuth (<a href="/facts/Antiulcer_agent/peMGnYCd">anti-ulcer</a>), gold (<a href="/facts/Arthritis/IQ1wyf21">anti-arthritic</a>), and iron (<a href="/facts/Anti-malarial_medication/8l4vNNNH">anti-malarial</a>) are also important in medicine.<a class="footnote-ref" id="fnref:155" href="#fn:155">155</a> Copper, zinc, silver, gold, or mercury are used in <a href="/facts/Antiseptic/ua05WK9M">antiseptic</a> formulations;<a class="footnote-ref" id="fnref:156" href="#fn:156">156</a> small amounts of some heavy metals are used to control algal growth in, for example, <a href="/facts/Cooling_tower/rnTgbsSA">cooling towers</a>.<a class="footnote-ref" id="fnref:157" href="#fn:157">157</a> Depending on their intended use as fertilisers or biocides, <a href="/facts/Agrochemical/Pf7FXeuG">agrochemicals</a> may contain heavy metals such as chromium, cobalt, nickel, copper, zinc, arsenic, cadmium, mercury, or lead.<a class="footnote-ref" id="fnref:158" href="#fn:158">158</a>
Selected heavy metals are used as catalysts in fuel processing (rhenium, for example), <a href="/facts/Synthetic_rubber/58Fq4XYx">synthetic rubber</a> and fibre production (bismuth), <a href="/facts/Catalytic_converter/KsP1ecPY">emission control devices</a> (palladium and platinum), and in <a href="/facts/Self-cleaning_oven/56maIKKY">self-cleaning ovens</a> (where <a href="/facts/Cerium_oxide/pqmIvGGc">cerium(IV) oxide</a> in the walls of such ovens helps <a href="/facts/Redox/Pyd5RVcj">oxidise</a> <a href="/facts/Carbon/ukrgQexo">carbon</a>-based cooking residues).<a class="footnote-ref" id="fnref:159" href="#fn:159">159</a> In soap chemistry, heavy metals form insoluble soaps that are used in <a href="/facts/Grease_(lubricant)/SoG6pwuV">lubricating greases</a>, paint dryers, and <a href="/facts/Fungicide/c1twQBYo">fungicides</a> (apart from lithium, the alkali metals and the <a href="/facts/Ammonium/jYm8wc1n">ammonium</a> ion form soluble soaps).<a class="footnote-ref" id="fnref:160" href="#fn:160">160</a>

<h3>Colouring and optics</h3>

The colours of <a href="/facts/Glass/hezRsAGf">glass</a>, <a href="/facts/Ceramic_glaze/eWJqJTYk">ceramic glazes</a>, <a href="/facts/Environmental_impact_of_paint/AlhprtEe">paints</a>, <a href="/facts/Pigment/I3clCYkF">pigments</a>, and <a href="/facts/Plastic/Kla5QItn">plastics</a> are commonly produced by the inclusion of heavy metals (or their compounds) such as chromium, manganese, cobalt, copper, zinc, <a href="/facts/Zirconium/y7gsoQFz">zirconium</a>, molybdenum, silver, tin, <a href="/facts/Praseodymium/2lnRJ9dH">praseodymium</a>, <a href="/facts/Neodymium/GzDkTIoI">neodymium</a>, <a href="/facts/Erbium/XEJlgJcx">erbium</a>, tungsten, iridium, gold, lead, or uranium.<a class="footnote-ref" id="fnref:161" href="#fn:161">161</a> <a href="/facts/Tattoo/l5QSeblC">Tattoo</a> inks may contain heavy metals, such as chromium, cobalt, nickel, and copper.<a class="footnote-ref" id="fnref:162" href="#fn:162">162</a> The high reflectivity of some heavy metals is important in the construction of <a href="/facts/Mirror/wMu4u6BB">mirrors</a>, including precision <a href="/facts/Astronomical_instrument/1KCmcxRW">astronomical instruments</a>. Headlight reflectors rely on the excellent reflectivity of a thin film of rhodium.<a class="footnote-ref" id="fnref:163" href="#fn:163">163</a>

<h3>Electronics, magnets, and lighting</h3>
Heavy metals or their compounds can be found in <a href="/facts/Electronic_component/F3NBVv4Q">electronic components</a>, <a href="/facts/Electrode/251PaKX8">electrodes</a>, and <a href="/facts/Electrical_wiring/Ibfa7Eq7">wiring</a> and <a href="/facts/Solar_panel/gufbEu8n">solar panels</a>. Molybdenum powder is used in <a href="/facts/Circuit_board/muSR2p43">circuit board</a> inks.<a class="footnote-ref" id="fnref:164" href="#fn:164">164</a> Home electrical systems, for the most part, are wired with copper wire for its good conducting properties.<a class="footnote-ref" id="fnref:165" href="#fn:165">165</a> Silver and gold are used in electrical and electronic devices, particularly in contact <a href="/facts/Switch/vqbNDgYm">switches</a>, as a result of their high electrical conductivity and capacity to resist or minimise the formation of impurities on their surfaces.<a class="footnote-ref" id="fnref:166" href="#fn:166">166</a> Heavy metals have been used in batteries for over 200 years, at least since <a href="/facts/Alessandro_Volta/W9rIYxmv">Volta</a> invented his copper and silver <a href="/facts/Voltaic_pile/9KoUfqGE">voltaic pile</a> in 1800.<a class="footnote-ref" id="fnref:167" href="#fn:167">167</a>
<a href="/facts/Magnet/vvrg6VSk">Magnets</a> are often made of heavy metals such as manganese, iron, cobalt, nickel, niobium, bismuth, praseodymium, neodymium, gadolinium, and <a href="/facts/Dysprosium/eMev6zGS">dysprosium</a>. Neodymium magnets are the strongest type of <a href="/facts/Magnet/vvrg6VSk">permanent magnet</a> commercially available. They are key components of, for example, car door locks, <a href="/facts/Starter_motor/4IFcgw83">starter motors</a>, <a href="/facts/Fuel_pump/kgwEn2HP">fuel pumps</a>, and <a href="/facts/Power_window/ImuPTqAR">power windows</a>.<a class="footnote-ref" id="fnref:168" href="#fn:168">168</a>
Heavy metals are used in <a href="/facts/Lighting/Gk54r8xE">lighting</a>, <a href="/facts/Laser/jk6PTvvT">lasers</a>, and <a href="/facts/Light-emitting_diode/gE8x4MDb">light-emitting diodes</a> (LEDs). <a href="/facts/Fluorescent_lighting/R8SlXCyg">Fluorescent lighting</a> relies on mercury vapour for its operation. <a href="/facts/Ruby_laser/rhnwSR4T">Ruby lasers</a> generate deep red beams by exciting chromium atoms in <a href="/facts/Aluminum_oxide/wXM9P6pI">aluminum oxide</a>; the lanthanides are also extensively employed in lasers. Copper, iridium, and platinum are used in <a href="/facts/Organic_LED/219L1aMJ">organic LEDs</a>.<a class="footnote-ref" id="fnref:169" href="#fn:169">169</a>

<h3>Nuclear</h3>

Because denser materials absorb more of certain types of radioactive emissions such as <a href="/facts/Gamma_ray/5Drf913J">gamma rays</a> than lighter ones, heavy metals are useful for <a href="/facts/Radiation_protection/5LaNNgXe">radiation shielding</a> and to <a href="/facts/Collimator/UAsMlkeh">focus radiation beams</a> in <a href="/facts/Linear_accelerator/GIz6Uc4x">linear accelerators</a> and <a href="/facts/Radiotherapy/j60q5EC6">radiotherapy</a> applications.
Niche uses of heavy metals with high atomic numbers occur in <a href="/facts/Diagnostic_imaging/pL6JyJEp">diagnostic imaging</a>, <a href="/facts/Transmission_electron_microscopy/Rpr8jpCn">electron microscopy</a>, and nuclear science. In diagnostic imaging, heavy metals such as cobalt or tungsten make up the anode materials found in <a href="/facts/X-ray_tube/tx0dTDqp">x-ray tubes</a>.<a class="footnote-ref" id="fnref:170" href="#fn:170">170</a> In electron microscopy, heavy metals such as lead, gold, palladium, platinum, or uranium have been used in the past to make conductive coatings and to introduce electron density into biological specimens by <a href="/facts/Staining/jqGqWEE1">staining</a>, <a href="/facts/Negative_staining/neI3a22v">negative staining</a>, or <a href="/facts/Evaporation_(deposition)/kdu4uIbJ">vacuum deposition</a>.<a class="footnote-ref" id="fnref:171" href="#fn:171">171</a> In nuclear science, nuclei of heavy metals such as chromium, iron, or zinc are sometimes fired at other heavy metal targets to produce <a href="/facts/Transuranium_element/a12PwdAw">superheavy elements</a>;<a class="footnote-ref" id="fnref:172" href="#fn:172">172</a> heavy metals are also employed as <a href="/facts/Spallation/k7AsUBbk">spallation</a> targets for the production of <a href="/facts/Neutron/oRCM1geb">neutrons</a><a class="footnote-ref" id="fnref:173" href="#fn:173">173</a> or isotopes of non-primordial elements such as astatine (using lead, bismuth, thorium, or uranium in the latter case).<a class="footnote-ref" id="fnref:174" href="#fn:174">174</a>

<h2 id="notes">Notes</h2>

<h3>Sources</h3>

<ul><li>Ahrland S., <a href="/facts/Jan-Olov_Liljenzin/12KfELln">Liljenzin</a> J. O. & Rydberg J. 1973, "Solution chemistry," in J. C. Bailar & <a href="/facts/Aubrey_Trotman-Dickenson/enQyFKBP">A. F. Trotman-Dickenson</a> (eds), Comprehensive Inorganic Chemistry, vol. 5, The Actinides, <a href="/facts/Pergamon_Press/qe6ctSTB">Pergamon Press</a>, Oxford.</li>
<li>Albutt M. & Dell R. 1963, The nitrites and sulphides of uranium, thorium and plutonium: A review of present knowledge, UK Atomic Energy Authority Research Group, <a href="/facts/Atomic_Energy_Research_Establishment/4UMoNfcP">Harwell</a>, Berkshire.</li>
<li>Ali H, Khan E (2018-01-02). <a href="https://www.tandfonline.com/doi/full/10.1080/02772248.2017.1413652">"What are heavy metals? Long-standing controversy over the scientific use of the term 'heavy metals' – proposal of a comprehensive definition"</a>. Toxicological & Environmental Chemistry. 100 (1): 6–19. <a href="/facts/Bibcode_(identifier)/9HtdQSGB">Bibcode</a>:<a href="https://ui.adsabs.harvard.edu/abs/2018TxEC..100....6A">2018TxEC..100....6A</a>. <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1080%2F02772248.2017.1413652">10.1080/02772248.2017.1413652</a>. <a href="/facts/ISSN_(identifier)/DPAflDvU">ISSN</a> <a href="https://search.worldcat.org/issn/0277-2248">0277-2248</a>.</li>
<li>Alves A. K., Berutti, F. A. & Sánche, F. A. L. 2012, "Nanomaterials and catalysis", in C. P. Bergmann & M. J. de Andrade (ads), Nanonstructured Materials for Engineering Applications, Springer-Verlag, Berlin, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3-642-19130-5.</li>
<li>Amasawa E., Yi Teah H., Yu Ting Khew, J., Ikeda I. & Onuki M. 2016, "Drawing Lessons from the Minamata Incident for the General Public: Exercise on Resilience, Minamata Unit AY2014", in M. Esteban, T. Akiyama, C. Chen, I. Ikea, T. Mino (eds), Sustainability Science: Field Methods and Exercises, Springer International, Switzerland, pp. 93–116, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1007%2F978-3-319-32930-7_5">10.1007/978-3-319-32930-7_5</a> <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3-319-32929-1.</li>
<li>Ariel E., Barta J. & Brandon D. 1973, "Preparation and properties of heavy metals", Powder Metallurgy International, vol. 5, no. 3, pp. 126–129.</li>
<li>Atlas R. M. 1986, Basic and Practical Microbiology, <a href="/facts/Macmillan_Publishers/enNEBMM2">Macmillan Publishing Company</a>, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-02-304350-5.</li>
<li>Australian Government 2016, <a href="http://www.npi.gov.au/">National Pollutant Inventory</a>, Department of the Environment and Energy, accessed 16 August 2016.</li>
<li>Baird C. & Cann M. 2012, Environmental Chemistry, 5th ed., <a href="/facts/W._H._Freeman_and_Company/sJ3zg32G">W. H. Freeman and Company</a>, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-4292-7704-4.</li>
<li>Baldwin D. R. & Marshall W. J. 1999, "Heavy metal poisoning and its laboratory investigation", <a href="/facts/Annals_of_Clinical_Biochemistry/pNeDx255">Annals of Clinical Biochemistry</a>, vol. 36, no. 3, pp. 267–300, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1177%2F000456329903600301">10.1177/000456329903600301</a>.</li>
<li>Ball J. L., Moore A. D. & Turner S. 2008, Ball and Moore's Essential Physics for Radiographers, 4th ed., <a href="/facts/Blackwell_Publishing/XUkBW8kE">Blackwell Publishing</a>, Chichester, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-4051-6101-5.</li>
<li>Bánfalvi G. 2011, "Heavy metals, trace elements and their cellular effects", in G. Bánfalvi (ed.), Cellular Effects of Heavy Metals, <a href="/facts/Axel_Springer_SE/vKBtswut">Springer</a>, Dordrecht, pp.  3–28, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-94-007-0427-5.</li>
<li>Baranoff E. 2015, "First-row transition metal complexes for the conversion of light into electricity and electricity into light", in W-Y Wong (ed.), Organometallics and Related Molecules for Energy Conversion, Springer, Heidelberg, pp. 61–90, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3-662-46053-5.</li>
<li>Berea E., Rodriguez-lbelo M. & Navarro J. A. R. 2016, "Platinum Group Metal—Organic frameworks" in S. Kaskel (ed.), The Chemistry of Metal-Organic Frameworks: Synthesis, Characterisation, and Applications, vol. 2, Wiley-VCH Weinheim, pp. 203–230, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3-527-33874-0.</li>
<li>Berger A. J. & Bruning N. 1979, Lady Luck's Companion: How to Play ... How to Enjoy ... How to Bet ... How to Win, Harper & Row, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-06-014696-2.</li>
<li>Berry L. G. & Mason B. 1959, Mineralogy: Concepts, Descriptions, Determinations, W. H. Freeman and Company, San Francisco.</li>
<li>Biddle H. C. & Bush G. L 1949, Chemistry Today, <a href="/facts/Rand_McNally/uyrkU0Pw">Rand McNally</a>, Chicago.</li>
<li>Bonchev D. & Kamenska V. 1981, "Predicting the properties of the 113–120 transactinide elements", <a href="/facts/The_Journal_of_Physical_Chemistry/v9He6WJ8">The Journal of Physical Chemistry</a>, vo. 85, no. 9, pp. 1177–1186, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1021%2Fj150609a021">10.1021/j150609a021</a>.</li>
<li>Bonetti A., Leone R., Muggia F. & Howell S. B. (eds) 2009, Platinum and Other Heavy Metal Compounds in Cancer Chemotherapy: Molecular Mechanisms and Clinical Applications, <a href="/facts/Humana/7XJI0wGw">Humana</a> Press, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-60327-458-6.</li>
<li>Booth H. S. 1957, Inorganic Syntheses, vol. 5, McGraw-Hill, New York.</li>
<li>Bradl H. E. 2005, "Sources and origins of heavy metals", in Bradl H. E. (ed.), Heavy Metals in the Environment: Origin, Interaction and Remediation, Elsevier, Amsterdam, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-12-088381-3.</li>
<li>Brady J. E. & Holum J. R. 1995, Chemistry: The Study of Matter and its Changes, 2nd ed., <a href="/facts/John_Wiley_%2526_Sons/53g3LqJc">John Wiley & Sons</a>, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-471-10042-3.</li>
<li>Brephohl E. & <a href="/facts/Tim_McCreight/8IckJGGs">McCreight T.</a> (ed) 2001, The Theory and Practice of Goldsmithing, C. Lewton-Brain trans., Brynmorgen Press, Portland, Maine, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-9615984-9-5.</li>
<li>Brown I. 1987, "Astatine: Its organonuclear chemistry and biomedical applications," in H. J. Emeléus & A. G. Sharpe (eds), Advances in Inorganic Chemistry, vol. 31, <a href="/facts/Academic_Press/qxoKjzFy">Academic Press</a>, Orlando, pp. 43–88, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-12-023631-2.</li>
<li>Bryson R. M. & Hammond C. 2005, "Generic methodologies for nanotechnology: Characterisation"', in R. Kelsall, I. W. Hamley & M. Geoghegan, Nanoscale Science and Technology, John Wiley & Sons, Chichester, pp. 56–129, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-470-85086-2.</li>
<li>Burkett B. 2010, Sport Mechanics for Coaches, 3rd ed., Human Kinetics, Champaign, Illinois, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-7360-8359-1.</li>
<li>Casey C. 1993, "Restructuring work: New work and new workers in post-industrial production", in R. P. Coulter & I. F. Goodson (eds), Rethinking Vocationalism: Whose Work/life is it?, Our Schools/Our Selves Education Foundation, Toronto, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-921908-15-9.</li>
<li>Chakhmouradian A.R., Smith M. P. & Kynicky J. 2015, "From "strategic" tungsten to "green" neodymium: A century of critical metals at a glance", Ore Geology Reviews, vol. 64, January, pp. 455–458, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1016%2Fj.oregeorev.2014.06.008">10.1016/j.oregeorev.2014.06.008</a>.</li>
<li><a href="/facts/Ephraim_Chambers/Jw3pGdyb">Chambers E.</a> 1743, "<a href="https://books.google.com/books?id=XUtOAAAAcAAJ&pg=PT126">Metal</a>", in Cyclopedia: Or an Universal Dictionary of Arts and Sciences (etc.), vol. 2, D. Midwinter, London.</li>
<li>Chandler D. E. & Roberson R. W. 2009, Bioimaging: Current Concepts in Light & Electron Microscopy, <a href="/facts/Jones_%2526_Bartlett_Publishers/Bz6vdDg8">Jones & Bartlett Publishers</a>, Boston, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-7637-3874-7.</li>
<li>Chawla N. & Chawla K. K. 2013, Metal matrix composites, 2nd ed., <a href="/facts/Springer_Science%252BBusiness_Media/nAesf6nT">Springer Science+Business Media</a>, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-4614-9547-5.</li>
<li>Chen J. & Huang K. 2006, "A new technique for extraction of platinum group metals by pressure cyanidation", Hydrometallurgy, vol. 82, nos. 3–4, pp. 164–171, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1016%2Fj.hydromet.2006.03.041">10.1016/j.hydromet.2006.03.041</a>.</li>
<li><a href="/facts/Matthew_Choptuik/Po5FSyhK">Choptuik M. W.</a>, Lehner L. & Pretorias F. 2015, "Probing strong-field gravity through numerical simulation", in <a href="/facts/Abhay_Ashtekar/HHtJBbnD">A. Ashtekar</a>, <a href="/facts/Beverly_Berger/B7G86GyB">B. K. Berger</a>, J. Isenberg & M. MacCallum (eds), General Relativity and Gravitation: A Centennial Perspective, Cambridge University Press, Cambridge, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-107-03731-1.</li>
<li><a href="/facts/Brian_Clegg_(writer)/eR5J6eMW">Clegg B</a> 2014, "<a href="https://www.chemistryworld.com/podcasts/osmium-tetraoxide/7656.article">Osmium tetroxide</a>", <a href="/facts/Chemistry_World/kYJKs768">Chemistry World</a>, accessed 2 September 2016.</li>
<li>Close F. 2015, Nuclear Physics: A Very Short Introduction, <a href="/facts/Oxford_University_Press/CYyTzzWG">Oxford University Press</a>, Oxford, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-19-871863-5.</li>
<li>Clugston M & Flemming R 2000, Advanced Chemistry, Oxford University, Oxford, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-19-914633-8.</li>
<li>Cole M., Lindeque P., Halsband C. & Galloway T. S. 2011, "Microplastics as contaminants in the marine environment: A review", Marine Pollution Bulletin, vol. 62, no. 12, pp. 2588–2597, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1016%2Fj.marpolbul.2011.09.025">10.1016/j.marpolbul.2011.09.025</a>.</li>
<li>Cole S. E. & Stuart K. R. 2000, "Nuclear and cortical histology for <a href="/facts/Bright-field_microscopy/pWu3Dqkr">brightfield microscopy</a>", in D. J. Asai & J. D. Forney (eds), Methods in Cell Biology, vol. 62, Academic Press, San Diego, pp. 313–322, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-12-544164-3.</li>
<li>Cotton S. A. 1997, Chemistry of Precious Metals, Blackie Academic & Professional, London, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-94-010-7154-3.</li>
<li>Cotton S. 2006, Lanthanide and Actinide Chemistry, reprinted with corrections 2007, <a href="/facts/John_Wiley_%2526_Sons/53g3LqJc">John Wiley & Sons</a>, Chichester, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-470-01005-1.</li>
<li>Cox P. A. 1997, The elements: Their Origin, Abundance and Distribution, <a href="/facts/Oxford_University_Press/CYyTzzWG">Oxford University Press</a>, Oxford, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-19-855298-7.</li>
<li>Crundwell F. K., Moats M. S., Ramachandran V., Robinson T. G. & Davenport W. G. 2011, Extractive Metallurgy of Nickel, Cobalt and Platinum Group Metals, Elsevier, Kidlington, Oxford, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-08-096809-4.</li>
<li>Cui X-Y., Li S-W., Zhang S-J., Fan Y-Y., Ma L. Q. 2015, "Toxic metals in children's toys and jewelry: Coupling bioaccessibility with risk assessment", <a href="/facts/Environmental_Pollution_(journal)/zeeG3ort">Environmental Pollution</a>, vol. 200, pp. 77–84, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1016%2Fj.envpol.2015.01.035">10.1016/j.envpol.2015.01.035</a>.</li>
<li>Dapena J. & Teves M. A. 1982, "Influence of the diameter of the hammer head on the distance of a hammer throw", Research Quarterly for Exercise and Sport, vol. 53, no. 1, pp. 78–81, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1080%2F02701367.1982.10605229">10.1080/02701367.1982.10605229</a>.</li>
<li>De Zuane J. 1997, Handbook of Drinking Water Quality, 2nd ed., John Wiley & Sons, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-471-28789-6.</li>
<li><a href="/facts/United_States_Department_of_the_Navy/bBdzKgXr">Department of the Navy</a> 2009, <a href="http://www.nmfs.noaa.gov/pr/pdfs/permits/goa_deis.pdf">Gulf of Alaska Navy Training Activities: Draft Environmental Impact Statement/Overseas Environmental Impact Statement</a>, U.S. Government, accessed 21 August 2016.</li>
<li>Deschlag J. O. 2011, "Nuclear fission", in A. Vértes, S. Nagy, Z. Klencsár, R. G. Lovas, F. Rösch (eds), Handbook of Nuclear Chemistry, 2nd ed., <a href="/facts/Springer_Science%252BBusiness_Media/nAesf6nT">Springer Science+Business Media</a>, Dordrecht, pp. 223–280, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-4419-0719-6.</li>
<li>Desoize B. 2004, "Metals and metal compounds in cancer treatment", <a href="/facts/Anticancer_Research/YhCMoFFR">Anticancer Research</a>, vol. 24, no. 3a, pp. 1529–1544, <a href="/facts/PMID_(identifier)/JlHAvMHt">PMID</a> <a href="https://pubmed.ncbi.nlm.nih.gov/15274320">15274320</a>.</li>
<li>Dev N. 2008, 'Modelling Selenium Fate and Transport in Great Salt Lake Wetlands', PhD dissertation, University of Utah, <a href="/facts/ProQuest/yoBIhGBy">ProQuest</a>, Ann Arbor, Michigan, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-549-86542-1.</li>
<li><a href="/facts/Vincent_Di_Maio/312VJnHC">Di Maio V. J. M.</a> 2001, Forensic Pathology, 2nd ed., CRC Press, Boca Raton, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 0-8493-0072-X.</li>
<li><a href="/facts/Vincent_Di_Maio/312VJnHC">Di Maio V. J. M.</a> 2016, Gunshot Wounds: Practical Aspects of Firearms, Ballistics, and Forensic Techniques, 3rd ed., <a href="/facts/CRC_Press/duTuH4hz">CRC Press</a>, Boca Raton, Florida, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-4987-2570-5.</li>
<li><a href="http://www.duffus.com/jhduffus1940.htm">Duffus J. H.</a> 2002, " <a href="http://www.iupac.org/publications/pac/2002/pdf/7405x0793.pdf">'Heavy metals'—A meaningless term?"</a>, <a href="/facts/Pure_and_Applied_Chemistry/9QdCDKxf">Pure and Applied Chemistry</a>, vol. 74, no. 5, pp. 793–807, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1351%2Fpac200274050793">10.1351/pac200274050793</a>.</li>
<li>Dunn P. 2009, <a href="http://www2.warwick.ac.uk/newsandevents/pressreleases/unusual_metals_could/">Unusual metals could forge new cancer drugs</a>, University of Warwick, accessed 23 March 2016.</li>
<li>Ebbing D. D. & Gammon S. D. 2017, General Chemistry, 11th ed., <a href="/facts/Cengage_Learning/Bda6bYXT">Cengage Learning</a>, Boston, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-305-58034-3.</li>
<li>Edelstein N. M., Fuger J., Katz J. L. & Morss L. R. 2010, "Summary and comparison of properties of the actinde and transactinide elements," in L. R. Morss, N. M. Edelstein & J. Fuger (eds), The Chemistry of the Actinide and Transactinide Elements, 4th ed., vol. 1–6, <a href="/facts/Springer_Publishing/JfRev59b">Springer</a>, Dordrecht, pp. 1753–1835, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-94-007-0210-3.</li>
<li>Eisler R. 1993, <a href="https://www.pwrc.usgs.gov/eisler/CHR_26_Zinc.pdf">Zinc Hazards to Fish, Wildlife, and Invertebrates: A Synoptic Review</a>, Biological Report 10, <a href="/facts/United_States_Department_of_the_Interior/uWllgxWx">U. S. Department of the Interior</a>, Laurel, Maryland, accessed 2 September 2016.</li>
<li>Elliott S. B. 1946, The Alkaline-earth and Heavy-metal Soaps, Reinhold Publishing Corporation, New York.</li>
<li><a href="/facts/John_Emsley/wzl2Ro6D">Emsley J.</a> 2011, <a href="https://books.google.com/books?id=2EfYXzwPo3UC&q=Emsley+%22Nature%27s+Building+Blocks%22">Nature's Building Blocks</a>, new edition, Oxford University Press, Oxford, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-19-960563-7.</li>
<li>Everts S. 2016, "<a href="http://cen.acs.org/articles/94/i33/chemicals-tattoo.html">What chemicals are in your tattoo</a>", <a href="/facts/Chemical_%2526_Engineering_News/2YFULpeW">Chemical & Engineering News</a>, vol. 94, no. 33, pp. 24–26.</li>
<li>Fournier J. 1976, "Bonding and the electronic structure of the actinide metals," <a href="/facts/Journal_of_Physics_and_Chemistry_of_Solids/e9tLeV7J">Journal of Physics and Chemistry of Solids</a>, vol 37, no. 2, pp. 235–244, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1016%2F0022-3697%2876%2990167-0">10.1016/0022-3697(76)90167-0</a>.</li>
<li>Frick J. P. (ed.) 2000, Woldman's Engineering Alloys, 9th ed., <a href="/facts/ASM_International_(society)/yuz90W8c">ASM International</a>, Materials Park, Ohio, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-87170-691-1.</li>
<li>Frommer H. H. & Stabulas-Savage J. J. 2014, Radiology for the Dental Professional, 9th ed., <a href="/facts/Mosby_(imprint)/davjSmnn">Mosby Inc.</a>, St. Louis, Missouri, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-323-06401-9.</li>
<li>Gidding J. C. 1973, Chemistry, Man, and Environmental Change: An Integrated Approach, Canfield Press, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-06-382790-5.</li>
<li><a href="/facts/Leopold_Gmelin/IHp6vhYS">Gmelin L.</a> 1849, Hand-book of chemistry, vol. III, Metals, translated from the German by H. Watts, Cavendish Society, London.</li>
<li>Goldsmith R. H. 1982, "Metalloids", <a href="/facts/Journal_of_Chemical_Education/fy9KJDa9">Journal of Chemical Education</a>, vol. 59, no. 6, pp. 526–527, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1021%2Fed059p526">10.1021/ed059p526</a>.</li>
<li>Gorbachev V. M., Zamyatnin Y. S. & Lbov A. A. 1980, Nuclear Reactions in Heavy Elements: A Data Handbook, Pergamon Press, Oxford, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-08-023595-0.</li>
<li><a href="/facts/Gordon_Gordh/6eMejI1e">Gordh G.</a> & Headrick D. 2003, A Dictionary of Entomology, CABI Publishing, Wallingford, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-85199-655-4.</li>
<li>* Goyer RA, Clarkson TW (1996). "Toxic effects of metals". Casarett and Doull's toxicology: the basic science of poisons 5. McGraw-Hill.</li>
<li>Greenberg B. R. & Patterson D. 2008, Art in Chemistry; Chemistry in Art, 2nd ed., Teachers Ideas Press, Westport, Connecticut, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-59158-309-7.</li>
<li>Gribbon J. 2016, 13.8: The Quest to Find the True Age of the Universe and the Theory of Everything, <a href="/facts/Yale_University_Press/oavMPaT7">Yale University Press</a>, New Haven, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-300-21827-5.</li>
<li>Gschneidner Jr., K. A. 1975, Inorganic compounds, in C. T. Horowitz (ed.), Scandium: Its Occurrence, Chemistry, Physics, Metallurgy, Biology and Technology, <a href="/facts/Academic_Press/qxoKjzFy">Academic Press</a>, London, pp. 152–251, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-12-355850-3.</li>
<li>Guandalini G. S., Zhang L., Fornero E., Centeno J. A., Mokashi V. P., Ortiz P. A., Stockelman M. D., Osterburg A. R. & Chapman G. G. 2011, "Tissue distribution of tungsten in mice following oral exposure to sodium tungstate," <a href="/facts/Chemical_Research_in_Toxicology/9ab5g2nM">Chemical Research in Toxicology</a>, vol. 24, no. 4, pp 488–493, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1021%2Ftx200011k">10.1021/tx200011k</a>.</li>
<li>Guney M. & Zagury G. J. 2012, "Heavy metals in toys and low-cost jewelry: Critical review of U.S. and Canadian legislations and recommendations for testing", <a href="/facts/Environmental_Science_%2526_Technology/vAgEA55q">Environmental Science & Technology</a>, vol. 48, pp. 1238–1246, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1021%2Fes4036122">10.1021/es4036122</a>.</li>
<li>Habashi F. 2009, "<a href="http://www.scs.illinois.edu/~mainzv/HIST/bulletin_open_access/v34-1/v34-1%20p30-31.pdf">Gmelin and his Handbuch"</a> <a href="https://web.archive.org/web/20160415132309/http://www.scs.illinois.edu/~mainzv/HIST/bulletin_open_access/v34-1/v34-1%20p30-31.pdf">Archived</a> 2016-04-15 at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a>, <a href="/facts/Bulletin_for_the_History_of_Chemistry/weq0w66c">Bulletin for the History of Chemistry</a>, vol. 34, no. 1, pp. 30–1.</li>
<li>Hadhazy A. 2016, "<a href="http://www.kavlifoundation.org/science-spotlights/cosmic-heavy-metals#.V4MEDleO7OY">Galactic 'gold mine' explains the origin of nature's heaviest elements</a> <a href="https://web.archive.org/web/20160524101329/http://www.kavlifoundation.org/science-spotlights/cosmic-heavy-metals#.V4MEDleO7OY">Archived</a> 2016-05-24 at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a>", Science Spotlights, 10 May 2016, accessed 11 July 2016.</li>
<li><a href="/facts/William_Kenneth_Hartmann/jBmfADSr">Hartmann W. K.</a> 2005, Moons & Planets, 5th ed., <a href="/facts/Thomson_Brooks%2fCole/EDNXn9VX">Thomson Brooks/Cole</a>, Belmont, California, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-534-49393-6.</li>
<li>Harvey P. J., Handley H. K. & Taylor M. P. 2015, "Identification of the sources of metal (lead) contamination in drinking waters in north-eastern Tasmania using lead isotopic compositions," Environmental Science and Pollution Research, vol. 22, no. 16, pp. 12276–12288, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1007%2Fs11356-015-4349-2">10.1007/s11356-015-4349-2</a> <a href="/facts/PMID_(identifier)/JlHAvMHt">PMID</a> <a href="https://pubmed.ncbi.nlm.nih.gov/25895456">25895456</a>.</li>
<li>Hasan S. E. 1996, Geology and Hazardous Waste Management, <a href="/facts/Prentice_Hall/bynWAuat">Prentice Hall</a>, Upper Saddle River, New Jersey, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-02-351682-5.</li>
<li>Hawkes S. J. 1997, "What is a "heavy metal"?", Journal of Chemical Education, vol. 74, no. 11, p. 1374, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1021%2Fed074p1374">10.1021/ed074p1374</a>.</li>
<li>Haynes W. M. 2015, CRC Handbook of Chemistry and Physics, 96th ed., CRC Press, Boca Raton, Florida, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-4822-6097-7.</li>
<li>Hendrickson D. J. 2916, "Effects of early experience on brain and body", in D. Alicata, N. N. Jacobs, A. Guerrero and M. Piasecki (eds), Problem-based Behavioural Science and Psychiatry 2nd ed., Springer, Cham, pp. 33–54, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3-319-23669-8.</li>
<li>Hermann A., <a href="/facts/Roald_Hoffmann/DHMcXIff">Hoffmann R.</a> & <a href="/facts/Neil_Ashcroft/q0h0CMfW">Ashcroft N. W.</a> 2013, "<a href="http://www.roaldhoffmann.com/sites/all/files/581.pdf">Condensed astatine: Monatomic and metallic</a> <a href="https://web.archive.org/web/20160316093932/http://www.roaldhoffmann.com/sites/all/files/581.pdf">Archived</a> 2016-03-16 at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a>", <a href="/facts/Physical_Review_Letters/rNP3XvYq">Physical Review Letters</a>, vol. 111, pp. 11604–1−11604-5, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1103%2FPhysRevLett.111.116404">10.1103/PhysRevLett.111.116404</a>.</li>
<li>Herron N. 2000, "Cadmium compounds," in Kirk-Othmer Encyclopedia of Chemical Technology, vol. 4, John Wiley & Sons, New York, pp. 507–523, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-471-23896-6.</li>
<li>Hoffman D. C., Lee D. M. & Pershina V. 2011, "Transactinide elements and future elements," in L. R. Morss, N. Edelstein, J. Fuger & J. J. Katz (eds), The Chemistry of the Actinide and Transactinide Elements, 4th ed., vol. 3, Springer, Dordrecht, pp. 1652–1752, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-94-007-0210-3.</li>
<li>Hofmann S. 2002, On Beyond Uranium: Journey to the End of the Periodic Table, <a href="/facts/Taylor_%2526_Francis/tLDanRJg">Taylor & Francis</a>, London, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-415-28495-0.</li>
<li>Housecroft J. E. 2008, Inorganic Chemistry, <a href="/facts/Elsevier/jkPSAEmR">Elsevier</a>, Burlington, Massachusetts, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-12-356786-4.</li>
<li>Howell N., Lavers J., Paterson D., Garrett R. & Banati R. 2012, <a href="http://www.ansto.gov.au/AboutANSTO/MediaCentre/News/ACS013097#sthash.wIvPum6r.dpuf">Trace metal distribution in feathers from migratory, pelagic birds</a>, <a href="/facts/Australian_Nuclear_Science_and_Technology_Organisation/dCdDEbPv">Australian Nuclear Science and Technology Organisation</a>, accessed 3 May 2014.</li>
<li>Hübner R., Astin K. B. & Herbert R. J. H. 2010, " 'Heavy metal'—time to move on from semantics to pragmatics?", <a href="/facts/Journal_of_Environmental_Monitoring/s6Cg3pAp">Journal of Environmental Monitoring</a>, vol. 12, pp. 1511–1514, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1039%2FC0EM00056F">10.1039/C0EM00056F</a>.</li>
<li>Ikehata K., Jin Y., Maleky N. & Lin A. 2015, "Heavy metal pollution in water resources in China—Occurrence and public health implications", in S. K. Sharma (ed.), Heavy Metals in Water: Presence, Removal and Safety, <a href="/facts/Royal_Society_of_Chemistry/1fg4xnqR">Royal Society of Chemistry</a>, Cambridge, pp. 141–167, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-84973-885-9.</li>
<li>International Antimony Association 2016, <a href="https://web.archive.org/web/20160912005613/http://www.antimony.com/en/antimony-compounds.aspx">Antimony compounds</a>, accessed 2 September 2016.</li>
<li>International Platinum Group Metals Association n.d., <a href="http://ipa-news.com/assets/sustainability/Primary%20Production%20Fact%20Sheet_LR.pdf?PHPSESSID=8f924aa0e30f81ba7fe97c7449665b58">The Primary Production of Platinum Group Metals (PGMs)</a>, accessed 4 September 2016.</li>
<li>Ismail A. F., Khulbe K. & Matsuura T. 2015, Gas Separation Membranes: Polymeric and Inorganic, Springer, Cham, Switzerland, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3-319-01095-3.</li>
<li><a href="/facts/IUPAC/2AV6myCK">IUPAC</a> 2016, "<a href="https://iupac.org/iupac-is-naming-the-four-new-elements-nihonium-moscovium-tennessine-and-oganesson/">IUPAC is naming the four new elements nihonium, moscovium, tennessine, and oganesson</a>" accessed 27 August 2016.</li>
<li>Iyengar G. V. 1998, "Reevaluation of the trace element content in Reference Man", Radiation Physics and Chemistry, vol. 51, nos 4–6, pp. 545–560, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1016%2FS0969-806X%2897%2900202-8">10.1016/S0969-806X(97)00202-8</a></li>
<li>Jackson J. & Summitt J. 2006, The Modern Guide to Golf Clubmaking: The Principles and Techniques of Component Golf Club Assembly and Alteration, 5th ed., Hireko Trading Company, City of Industry, California, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-9619413-0-7.</li>
<li>Järup L 2003, "Hazards of heavy metal contamination", <a href="/facts/British_Medical_Bulletin/IfKTWWIQ">British Medical Bulletin</a>, vol. 68, no. 1, pp. 167–182, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1093%2Fbmb%2Fldg032">10.1093/bmb/ldg032</a>.</li>
<li>Jones C. J. 2001, d- and f-Block Chemistry, Royal Society of Chemistry, Cambridge, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-85404-637-9.</li>
<li>Kantra S. 2001, "What's new", <a href="/facts/Popular_Science/cnhLw9rI">Popular Science</a>, vol. 254, no. 4, April, p. 10.</li>
<li>Keller C., Wolf W. & Shani J. 2012, "Radionuclides, 2. Radioactive elements and artificial radionuclides", in <a href="/facts/Fritz_Ullmann/EEKjXEM9">F. Ullmann</a> (ed.), <a href="/facts/Ullmann%2527s_Encyclopedia_of_Industrial_Chemistry/2Cx6SsUM">Ullmann's Encyclopedia of Industrial Chemistry</a>, vol. 31, Wiley-VCH, Weinheim, pp. 89–117, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1002%2F14356007.o22_o15">10.1002/14356007.o22_o15</a>.</li>
<li>King R. B. 1995, Inorganic Chemistry of Main Group Elements, <a href="/facts/Wiley-VCH/4oQWIG4d">Wiley-VCH</a>, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-56081-679-9.</li>
<li><a href="/facts/Izaak_Kolthoff/YT6bbV5V">Kolthoff I. M.</a> & Elving P. J. FR 1964, Treatise on Analytical Chemistry, part II, vol. 6, Interscience Encyclopedia, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-07-038685-3.</li>
<li>Korenman I. M. 1959, "Regularities in properties of thallium", Journal of General Chemistry of the USSR, English translation, Consultants Bureau, New York, vol. 29, no. 2, pp. 1366–90, <a href="/facts/ISSN_(identifier)/DPAflDvU">ISSN</a> <a href="https://www.worldcat.org/search?fq=x0:jrnl&q=n2:0022-1279">0022-1279</a>.</li>
<li>Kozin L. F. & Hansen S. C. 2013, Mercury Handbook: Chemistry, Applications and Environmental Impact, <a href="/facts/RSC_Publishing/1fg4xnqR">RSC Publishing</a>, Cambridge, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-84973-409-7.</li>
<li>Kumar R., Srivastava P. K., Srivastava S. P. 1994, "Leaching of heavy metals (Cr, Fe, and Ni) from stainless steel utensils in food simulates and food materials", Bulletin of Environmental Contamination and Toxicology, vol. 53, no. 2, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1007%2FBF00192942">10.1007/BF00192942</a>, pp. 259–266.</li>
<li>Lach K., Steer B., Gorbunov B., Mička V. & Muir R. B. 2015, "Evaluation of exposure to airborne heavy metals at gun shooting ranges", <a href="/facts/The_Annals_of_Occupational_Hygiene/YtMv0xIF">The Annals of Occupational Hygiene</a>, vol. 59, no. 3, pp. 307–323, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1093%2Fannhyg%2Fmeu097">10.1093/annhyg/meu097</a>.</li>
<li>Landis W., Sofield R. & Yu M-H. 2010, Introduction to Environmental Toxicology: Molecular Substructures to Ecological Landscapes, 4th ed., CRC Press, Boca Raton, Florida, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-4398-0411-7.</li>
<li>Lane T. W., Saito M. A., George G. N., Pickering, I. J., Prince R. C. & Morel F. M. M. 2005, "Biochemistry: A cadmium enzyme from a marine diatom", <a href="/facts/Nature_(journal)/XmlJXkFx">Nature</a>, vol. 435, no. 7038, p. 42, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1038%2F435042a">10.1038/435042a</a>.</li>
<li>Lee J. D. 1996, Concise Inorganic Chemistry, 5th ed., <a href="/facts/Blackwell_Science/XUkBW8kE">Blackwell Science</a>, Oxford, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-632-05293-6.</li>
<li>Leeper G. W. 1978, Managing the Heavy Metals on the Land <a href="/facts/Marcel_Dekker/HdEhf51X">Marcel Dekker</a>, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 0-8247-6661-X.</li>
<li>Lemly A. D. 1997, "A teratogenic deformity index for evaluating impacts of selenium on fish populations", Ecotoxicology and Environmental Safety, vol. 37, no. 3, pp. 259–266, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1006%2Feesa.1997.1554">10.1006/eesa.1997.1554</a>.</li>
<li>Lide D. R. (ed.) 2004, CRC Handbook of Chemistry and Physics, 85th ed., CRC Press, Boca Raton, Florida, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-8493-0485-9.</li>
<li>Liens J. 2010, "Heavy metals as pollutants", in B. Warf (ed.), Encyclopaedia of Geography, Sage Publications, Thousand Oaks, California, pp. 1415–1418, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-4129-5697-0.</li>
<li>Lima E., Guerra R., Lara V. & Guzmán A. 2013, "Gold nanoparticles as efficient antimicrobial agents for Escherichia coli and Salmonella typhi " <a href="/facts/Chemistry_Central/b8pr31w3">Chemistry Central</a>, vol. 7:11, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1186%2F1752-153X-7-11">10.1186/1752-153X-7-11</a> <a href="/facts/PMID_(identifier)/JlHAvMHt">PMID</a> <a href="https://pubmed.ncbi.nlm.nih.gov/23331621">23331621</a> <a href="/facts/PMC_(identifier)/dX1zMt71">PMC</a> <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3556127/">3556127</a>.</li>
<li>Litasov K. D. & Shatskiy A. F. 2016, "Composition of the Earth's core: A review", Russian Geology and Geophysics, vol. 57, no. 1, pp. 22–46, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1016%2Fj.rgg.2016.01.003">10.1016/j.rgg.2016.01.003</a>.</li>
<li>Livesey A. 2012, Advanced Motorsport Engineering, <a href="/facts/Routledge/aSwcES11">Routledge</a>, London, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-7506-8908-3.</li>
<li>Livingston R. A. 1991, "Influence of the Environment on the Patina of the Statue of Liberty", <a href="/facts/Environmental_Science_%2526_Technology/vAgEA55q">Environmental Science & Technology</a>, vol. 25, no. 8, pp. 1400–1408, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1021%2Fes00020a006">10.1021/es00020a006</a>.</li>
<li>Longo F. R. 1974, General Chemistry: Interaction of Matter, Energy, and Man, <a href="/facts/McGraw-Hill/oG8VpKJT">McGraw-Hill</a>, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-07-038685-3.</li>
<li>Love M. 1998, Phasing Out Lead from Gasoline: Worldwide Experience and Policy Implications, World Bank Technical Paper volume 397, <a href="/facts/The_World_Bank/9z4A2PDl">The World Bank</a>, Washington DC, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 0-8213-4157-X.</li>
<li>Lyman W. J. 1995, "Transport and transformation processes", in Fundamentals of Aquatic Toxicology, G. M. Rand (ed.), Taylor & Francis, London, pp. 449–492, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-56032-090-6.</li>
<li>Macintyre J. E. 1994, Dictionary of inorganic compounds, supplement 2, Dictionary of Inorganic Compounds, vol. 7, <a href="/facts/Chapman_%2526_Hall/roCcaakR">Chapman & Hall</a>, London, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-412-49100-9.</li>
<li>MacKay K. M., MacKay R. A. & Henderson W. 2002, Introduction to Modern Inorganic Chemistry, 6th ed., Nelson Thornes, Cheltenham, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-7487-6420-4.</li>
<li>Magee R. J. 1969, Steps to Atomic Power, Cheshire for La Trobe University, Melbourne.</li>
<li>Magill F. N. I (ed.) 1992, Magill's Survey of Science, Physical Science series, vol. 3, Salem Press, Pasadena, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-89356-621-0.</li>
<li>Martin M. H. & Coughtrey P. J. 1982, Biological Monitoring of Heavy Metal Pollution, Applied Science Publishers, London, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-85334-136-9.</li>
<li>Massarani M. 2015, "<a href="http://www.rsc.org/chemistryworld/2015/11/brazil-mine-disaster-dam-collapse">Brazilian mine disaster releases dangerous metals</a>," Chemistry World, November 2015, accessed 16 April 2016.</li>
<li>Masters C. 1981, Homogenous Transition-metal Catalysis: A Gentle Art, Chapman and Hall, London, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-412-22110-1.</li>
<li>Matyi R. J. & Baboian R. 1986, "An X-ray Diffraction Analysis of the Patina of the Statue of Liberty", Powder Diffraction, vol. 1, no. 4, pp. 299–304, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1017%2FS0885715600011970">10.1017/S0885715600011970</a>.</li>
<li>McColm I. J. 1994, Dictionary of Ceramic Science and Engineering, 2nd ed., Springer Science+Business Media, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-4419-3235-8.</li>
<li>McCurdy, Richard M. (1975). Qualities and quantities: preparation for college chemistry. New York: Harcourt Brace Jovanovich. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-15-574100-3.</li>
<li>McLemore V. T. (ed.) 2008, Basics of Metal Mining Influenced Water, vol. 1, Society for Mining, Metallurgy, and Exploration, Littleton, Colorado, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-87335-259-8.</li>
<li>McQueen K. G. 2009, Regolith geochemistry, in K. M. Scott & C. F. Pain (eds), Regolith Science, <a href="/facts/CSIRO_Publishing/KjEKYMkP">CSIRO Publishing</a>, Collingwood, Victoria, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-643-09396-6.</li>
<li><a href="/facts/Joseph_William_Mellor/qVP4RzTg">Mellor J. W.</a> 1924, A comprehensive Treatise on Inorganic and Theoretical Chemistry, vol. 5, <a href="/facts/Longmans%2c_Green_and_Company/l5JQ1NGz">Longmans, Green and Company</a>, London.</li>
<li>Moore J. W. & Ramamoorthy S. 1984, Heavy Metals in Natural Waters: Applied Monitoring and Impact Assessment, <a href="/facts/Springer_Verlag/nAesf6nT">Springer Verlag</a>, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-4612-9739-0.</li>
<li>Morris C. G. 1992, Academic Press Dictionary of Science and Technology, <a href="/facts/Harcourt_Brace_Jovanovich/JJoDPsh6">Harcourt Brace Jovanovich</a>, San Diego, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-12-200400-1.</li>
<li>Morstein J. H. 2005, "Fat Man", in E. A. Croddy & Y. Y. Wirtz (eds), Weapons of Mass Destruction: An Encyclopedia of Worldwide Policy, Technology, and History, <a href="/facts/ABC-CLIO/7B9JFAeq">ABC-CLIO</a>, Santa Barbara, California, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-85109-495-0.</li>
<li>Moselle B. (ed.) 2005, 2004 National Home Improvement Estimator, Craftsman Book Company, Carlsbad, California, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-57218-150-2.</li>
<li>Naja G. M. & Volesky B. 2009, "Toxicity and sources of Pb, Cd, Hg, Cr, As, and radionuclides", in L. K. Wang, J. P. Chen, Y. Hung & N. K. Shammas, Heavy Metals in the Environment, CRC Press, Boca Raton, Florida, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-4200-7316-4.</li>
<li>Nakbanpote W., Meesungneon O. & Prasad M. N. V. 2016, "Potential of ornamental plants for phytoremediation of heavy metals and income generation", in M. N. V. Prasad (ed.), Bioremediation and Bioeconomy, <a href="/facts/Elsevier/jkPSAEmR">Elsevier</a>, Amsterdam, pp. 179–218, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-12-802830-8.</li>
<li>Nathans M. W. 1963, Elementary Chemistry, <a href="/facts/Prentice_Hall/bynWAuat">Prentice Hall</a>, Englewood Cliffs, New Jersey.</li>
<li>National Materials Advisory Board 1971, Trends in the Use of Depleted Uranium, National Academy of Sciences – National Academy of Engineering, Washington DC.</li>
<li>National Materials Advisory Board 1973, Trends in Usage of Tungsten, <a href="/facts/National_Academy_of_Sciences/M3oePVeG">National Academy of Sciences</a> – <a href="/facts/National_Academy_of_Engineering/6RCqfvXM">National Academy of Engineering</a>, Washington DC.</li>
<li><a href="/facts/National_Organization_for_Rare_Disorders/dD7CKx2J">National Organization for Rare Disorders</a> 2015, <a href="http://rarediseases.org/rare-diseases/heavy-metal-poisoning/">Heavy metal poisoning</a>, accessed 3 March 2016.</li>
<li>Natural Resources Canada 2015, "<a href="http://www.geomag.nrcan.gc.ca/mag_fld/fld-en.php">Generation of the Earth's magnetic field</a>", accessed 30 August 2016.</li>
<li>Nieboer E. & Richardson D. 1978, "Lichens and 'heavy metals' ", International Lichenology Newsletter, vol. 11, no. 1, pp. 1–3.</li>
<li>Nieboer E. & Richardson D. H. S. 1980, "The replacement of the nondescript term 'heavy metals' by a biologically and chemically significant classification of metal ions", <a href="/facts/Environmental_Pollution_(journal)/zeeG3ort">Environmental Pollution</a> Series B, Chemical and Physical, vol. 1, no. 1, pp. 3–26, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1016%2F0143-148X%2880%2990017-8">10.1016/0143-148X(80)90017-8</a>.</li>
<li>Nzierżanowski K. & Gawroński S. W. 2012, "<a href="http://journal.young-scientists.eu/index.php/isuues/file/78-heavy-metal-concentration-in-plants-growing-on-the-vicinity-of-railroad-tracks-a-pilot-study">Heavy metal concentration in plants growing on the vicinity of railroad tracks: a pilot study</a>", Challenges of Modern Technology, vol. 3, no. 1, pp. 42–45, <a href="/facts/ISSN_(identifier)/DPAflDvU">ISSN</a> <a href="https://www.worldcat.org/search?fq=x0:jrnl&q=n2:2353-4419">2353-4419</a>, accessed 21 August 2016.</li>
<li>Ohlendorf H. M. 2003, "Ecotoxicology of selenium", in D. J. Hoffman, B. A. Rattner, G. A. Burton & <a href="/facts/John_Cairns_(biochemist)/IBltp6yL">J. Cairns</a>, Handbook of Ecotoxicology, 2nd ed., <a href="/facts/Lewis_Publishers/duTuH4hz">Lewis Publishers</a>, Boca Raton, pp. 466–491, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-56670-546-2.</li>
<li>Ondreička R., Kortus J. & Ginter E. 1971, "Aluminium, its absorption, distribution, and effects on phosphorus metabolism", in S. C. Skoryna & D. Waldron-Edward (eds), Intestinal Absorption of Metal Ions, Trace Elements and Radionuclides, Pergamon press, Oxford.</li>
<li>Ong K. L., Tan T. H. & Cheung W. L. 1997, "Potassium permanganate poisoning—a rare cause of fatal poisoning", Journal of Accident & Emergency Medicine, vol. 14, no. 1, pp. 43–45, <a href="/facts/PMC_(identifier)/dX1zMt71">PMC</a> <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1342846/">1342846</a>.</li>
<li><a href="/facts/Oxford_English_Dictionary/qaxKX8Bc">Oxford English Dictionary</a> 1989, 2nd ed., Oxford University Press, Oxford, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-19-861213-1.</li>
<li>Pacheco-Torgal F., Jalali S. & Fucic A. (eds) 2012, Toxicity of building materials, <a href="/facts/Woodhead_Publishing/rWgKfdx9">Woodhead Publishing</a>, Oxford, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-85709-122-2.</li>
<li><a href="/facts/Thanu_Padmanabhan/8I6Q5z1P">Padmanabhan T.</a> 2001, Theoretical Astrophysics, vol. 2, Stars and Stellar Systems, <a href="/facts/Cambridge_University_Press/fgEBSSRq">Cambridge University Press</a>, Cambridge, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-521-56241-6.</li>
<li>Pan W. & Dai J. 2015, "ADS based on linear accelerators", in W. Chao & W. Chou (eds), Reviews of accelerator science and technology, vol. 8, Accelerator Applications in Energy and Security, <a href="/facts/World_Scientific/qJPTP0Yk">World Scientific</a>, Singapore, pp. 55–76, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 981-3108-89-4.</li>
<li>Parish R. V. 1977, The Metallic Elements, <a href="/facts/Longman/l5JQ1NGz">Longman</a>, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-582-44278-8.</li>
<li>Perry J. & Vanderklein E. L. Water Quality: Management of a Natural Resource, Blackwell Science, Cambridge, Massachusetts <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 0-86542-469-1.</li>
<li>Pickering N. C. 1991, The Bowed String: Observations on the Design, Manufacture, Testing and Performance of Strings for Violins, Violas and Cellos, Amereon, Mattituck, New York.</li>
<li>Podosek F. A. 2011, "Noble gases", in H. D. Holland & <a href="/facts/Karl_Turekian/JtnqM0wN">K. K. Turekian</a> (eds), Isotope Geochemistry: From the Treatise on Geochemistry, Elsevier, Amsterdam, pp. 467–492, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-08-096710-3.</li>
<li>Podsiki C. 2008, "<a href="http://www.conservation-us.org/docs/default-source/resource-guides/heavy-metals-their-salts-and-other-compounds.pdf">Heavy metals, their salts, and other compounds</a>", <a href="/facts/American_Institute_for_Conservation/0ebdYUr9">AIC News</a>, November, special insert, pp. 1–4.</li>
<li>Preschel J. July 29, 2005, "<a href="http://www.cbsnews.com/news/green-bullets-not-so-eco-friendly/">Green bullets not so eco-friendly</a>", <a href="/facts/CBS_News/E1IB4hb0">CBS News</a>, accessed 18 March 2016.</li>
<li>Preuss P. 17 July 2011, "<a href="http://newscenter.lbl.gov/2011/07/17/kamland-geoneutrinos/">What keeps the Earth cooking?</a>," Berkeley Lab, accessed 17 July 2016.</li>
<li><a href="/facts/Carlos_Prieto_(cellist)/EolEKk8C">Prieto C.</a> 2011, The Adventures of a Cello: Revised Edition, with a New Epilogue, <a href="/facts/University_of_Texas_Press/7mIDlRsh">University of Texas Press</a>, Austin, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-292-72393-1</li>
<li>Raghuram P., Soma Raju I. V. & Sriramulu J. 2010, "Heavy metals testing in active pharmaceutical ingredients: an alternate approach", <a href="/facts/Pharmazie/w3ylcN42">Pharmazie</a>, vol. 65, no. 1, pp. 15–18, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1691%2Fph.2010.9222">10.1691/ph.2010.9222</a>.</li>
<li>Rainbow P. S. 1991, "The biology of heavy metals in the sea", in J. Rose (ed.), Water and the Environment, <a href="/facts/Gordon_and_Breach_Science_Publishers/tLDanRJg">Gordon and Breach Science Publishers</a>, Philadelphia, pp. 415–432, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-2-88124-747-7.</li>
<li>Rand G. M., Wells P. G. & McCarty L. S. 1995, "Introduction to aquatic toxicology", in G. M. Rand (ed.), Fundamentals of Aquatic Toxicology: Effects, Environmental Fate and Risk Assessment, 2nd ed., Taylor & Francis, London, pp. 3–70, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-56032-090-6.</li>
<li>Rankin W. J. 2011, Minerals, Metals and Sustainability: Meeting Future Material Needs, CSIRO Publishing, Collingwood, Victoria, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-643-09726-1.</li>
<li>Rasic-Milutinovic Z. & Jovanovic D. 2013, "Toxic metals", in M. Ferrante, G. Oliveri Conti, Z. Rasic-Milutinovic & D. Jovanovic (eds), Health Effects of Metals and Related Substances in Drinking Water, <a href="/facts/International_Water_Association/zPvj8pHl">IWA Publishing</a>, London, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-68015-557-0.</li>
<li>Raymond R. 1984, Out of the Fiery Furnace: The Impact of Metals on the History of Mankind, <a href="/facts/Macmillan_Publishing/enNEBMM2">Macmillan</a>, South Melbourne, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-333-38024-6.</li>
<li>Rebhandl W., Milassin A., Brunner L., Steffan I., Benkö T., Hörmann M., Burschen J. 2007, "In vitro study of ingested coins: Leave them or retrieve them?", Journal of Paediatric Surgery, vol. 42, no. 10, pp. 1729–1734, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1016%2Fj.jpedsurg.2007.05.031">10.1016/j.jpedsurg.2007.05.031</a>.</li>
<li>Rehder D. 2010, Chemistry in Space: From Interstellar Matter to the Origin of Life, Wiley-VCH, Weinheim, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3-527-32689-1.</li>
<li>Renner H., Schlamp G., Kleinwächter I., Drost E., Lüchow H. M., Tews P., Panster P., Diehl M., Lang J., Kreuzer T., Knödler A., Starz K. A., Dermann K., Rothaut J., Drieselmann R., Peter C. & Schiele R. 2012, "Platinum Group Metals and compounds", in F. Ullmann (ed.), Ullmann's Encyclopedia of Industrial Chemistry, vol. 28, Wiley-VCH, Weinheim, pp. 317–388, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1002%2F14356007.a21_075">10.1002/14356007.a21_075</a>.</li>
<li>Reyes J. W. 2007, <a href="http://www3.amherst.edu/~jwreyes/papers/LeadCrimeNBERWP13097.pdf">Environmental Policy as Social Policy? The Impact of Childhood Lead Exposure on Crime</a>, <a href="/facts/National_Bureau_of_Economic_Research/oQREczIe">National Bureau of Economic Research</a> Working Paper 13097, accessed 16 October 2016.</li>
<li><a href="/facts/Ian_Ridpath/vKwa0HRu">Ridpath I.</a> (ed.) 2012, Oxford Dictionary of Astronomy, 2nd ed. rev., Oxford University Press, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-19-960905-5.</li>
<li>Rockhoff H. 2012, America's Economic Way of War: War and the US Economy from the Spanish–American War to the Persian Gulf War, Cambridge University Press, Cambridge, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-521-85940-0.</li>
<li>Roe J. & Roe M. 1992, "World's coinage uses 24 chemical elements", World Coinage News, vol. 19, no. 4, pp. 24–25; no. 5, pp. 18–19.</li>
<li>Russell A. M. & Lee K. L. 2005, Structure–Property Relations in Nonferrous Metals, John Wiley & Sons, Hoboken, New Jersey, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-471-64952-6.</li>
<li>Rusyniak D. E., Arroyo A., Acciani J., Froberg B., Kao L. & Furbee B. 2010, "Heavy metal poisoning: Management of intoxication and antidotes", in A. Luch (ed.), Molecular, Clinical and Environmental Toxicology, vol. 2, Birkhäuser Verlag, Basel, pp. 365–396, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3-7643-8337-4.</li>
<li>Ryan J. 2012, Personal Financial Literacy, 2nd ed., South-Western, Mason, Ohio, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-8400-5829-4.</li>
<li>Samsonov G. V. (ed.) 1968, Handbook of the Physicochemical Properties of the Elements, IFI-Plenum, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-4684-6066-7.</li>
<li>Sanders R. 2003, "<a href="http://www.berkeley.edu/news/media/releases/2003/12/10_heat.shtml">Radioactive potassium may be major heat source in Earth's core</a>," UCBerkelyNews, 10 December, accessed 17 July 20016.</li>
<li>Schweitzer P. A. 2003, Metallic materials: Physical, Mechanical, and Corrosion properties, Marcel Dekker, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-8247-0878-8.</li>
<li><a href="/facts/George_K._Schweitzer/6DE9Evdx">Schweitzer G. K.</a> & Pesterfield L. L. 2010, The Aqueous Chemistry of the Elements, Oxford University Press, Oxford, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-19-539335-4.</li>
<li>Scott R. M. 1989, Chemical Hazards in the Workplace, CRC Press, Boca Raton, Orlando, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-87371-134-0.</li>
<li>Scoullos M. (ed.), Vonkeman G. H., Thornton I. & Makuch Z. 2001, Mercury — Cadmium — Lead Handbook for Sustainable Heavy Metals Policy and Regulation, <a href="/facts/Kluwer_Academic_Publishers/nAesf6nT">Kluwer Academic Publishers</a>, Dordrecht, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-4020-0224-3.</li>
<li>Selinger B. 1978, Chemistry in the Market Place, 2nd ed., <a href="/facts/Australian_National_University_Press/wlYxbSmL">Australian National University Press</a>, Canberra, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-7081-0728-7.</li>
<li>Seymour R. J. & O'Farrelly J. 2012, "Platinum Group Metals", Kirk-Other Encyclopaedia of Chemical Technology, John Wiley & Sons, New York, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1002%2F0471238961.1612012019052513.a01.pub3">10.1002/0471238961.1612012019052513.a01.pub3</a>.</li>
<li>Shaw B. P., Sahu S. K. & Mishra R. K. 1999, "Heavy metal induced oxidative damage in terrestrial plants", in M. N. V. Prased (ed.), Heavy Metal Stress in Plants: From Biomolecules to Ecosystems Springer-Verlag, Berlin, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3-540-40131-5.</li>
<li>Shedd K. B. 2002, "<a href="https://minerals.usgs.gov/minerals/pubs/commodity/tungsten/tungsmyb02.pdf">Tungsten"</a>, Minerals Yearbook, <a href="/facts/United_States_Geological_Survey/nVaGtMjl">United States Geological Survey</a>.</li>
<li><a href="/facts/Nevil_Sidgwick/kYRJDNeV">Sidgwick N. V.</a> 1950, The Chemical Elements and their Compounds, vol. 1, Oxford University Press, London.</li>
<li>Silva R. J. 2010, "Fermium, mendelevium, nobelium, and lawrencium", in L. R. Morss, N. Edelstein & J. Fuger (eds), The Chemistry of the Actinide and Transactinide Elements, vol. 3, 4th ed., Springer, Dordrecht, pp. 1621–1651, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-94-007-0210-3.</li>
<li>Spolek G. 2007, "Design and materials in fly fishing", in A. Subic (ed.), Materials in Sports Equipment, Volume 2, <a href="/facts/Woodhead_Publishing/rWgKfdx9">Woodhead Publishing</a>, Abington, Cambridge, pp. 225–247, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-84569-131-8.</li>
<li>Stankovic S. & Stankocic A. R. 2013, "Bioindicators of toxic metals", in E. Lichtfouse, J. Schwarzbauer, D. Robert 2013, Green materials for energy, products and depollution, Springer, Dordrecht, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-94-007-6835-2, pp. 151–228.</li>
<li>State Water Control Resources Board 1987, Toxic substances monitoring program, issue 79, part 20 of the Water Quality Monitoring Report, Sacramento, California.</li>
<li>Technical Publications 1953, <a href="/facts/Fire_Engineering/FsC2DlT7">Fire Engineering</a>, vol. 111, p. 235, <a href="/facts/ISSN_(identifier)/DPAflDvU">ISSN</a> <a href="https://www.worldcat.org/search?fq=x0:jrnl&q=n2:0015-2587">0015-2587</a>.</li>
<li><a href="/facts/The_Minerals%2c_Metals_and_Materials_Society/zTgyN9KP">The Minerals, Metals and Materials Society</a>, <a href="https://web.archive.org/web/20160606203401/http://www.tms.org/administration/technicalDivisions.aspx?iframe=LMD%2FLMDmain.asp">Light Metals Division 2016</a>, accessed 22 June 2016.</li>
<li>The <a href="/facts/United_States_Pharmacopeia/CyYDYG8m">United States Pharmacopeia</a> 1985, 21st revision, The United States Pharmacopeial Convention, Rockville, Maryland, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-913595-04-6.</li>
<li>Thorne P. C. L. & Roberts E. R. 1943, Fritz Ephraim Inorganic Chemistry, 4th ed., Gurney and Jackson, London.</li>
<li>Tisza M. 2001, Physical Metallurgy for Engineers, ASM International, Materials Park, Ohio, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-87170-725-3.</li>
<li>Tokar E. J., Boyd W. A., Freedman J. H. & Wales M. P. 2013, "<a href="http://accesspharmacy.mhmedical.com/content.aspx?bookid=958§ionid=53483748">Toxic effects of metals</a>", in C. D. Klaassen (ed.), Casarett and Doull's Toxicology: the Basic Science of Poisons, 8th ed., <a href="/facts/McGraw-Hill_Medical/srSyQSsY">McGraw-Hill Medical</a>, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-07-176923-5, accessed 9 September 2016 (subscription required).</li>
<li>Tomasik P. & Ratajewicz Z. 1985, Pyridine metal complexes, vol. 14, no. 6A, The Chemistry of Heterocyclic Compounds, John Wiley & Sons, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-471-05073-5.</li>
<li>Topp N. E. 1965, The Chemistry of the Rare-earth Elements, Elsevier Publishing Company, Amsterdam.</li>
<li>Torrice M. 2016, "<a href="http://cen.acs.org/articles/94/i7/Lead-Ended-Flints-Tap-Water.html">How lead ended up in Flint's tap water</a>," Chemical & Engineering News, vol. 94, no. 7, pp. 26–27.</li>
<li>Tretkoff E. 2006, "<a href="https://www.aps.org/publications/apsnews/200603/history.cfm">March 20, 1800: Volta describes the Electric Battery</a>", APS News, This Month in Physics History, <a href="/facts/American_Physical_Society/DCkkU6dD">American Physical Society</a>, accessed 26 August 2016.</li>
<li>Uden P. C. 2005, 'Speciation of Selenium,' in R. Cornelis, J. Caruso, H. Crews & K. Heumann (eds), Handbook of Elemental Speciation II: Species in the Environment, Food, Medicine and Occupational Health, John Wiley & Sons, Chichester, pp. 346–65, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-470-85598-0.</li>
<li>United States Environmental Protection Agency 1988, Ambient Aquatic Life Water Quality Criteria for Antimony (III), draft, Office of Research and Development, Environmental Research Laboratories, Washington.</li>
<li><a href="/facts/United_States_Environmental_Protection_Agency/ghI985SI">United States Environmental Protection Agency</a> 2014, <a href="https://www.epa.gov/sites/production/files/2014-03/documents/ffrrofactsheet_contaminant_tungsten_january2014_final.pdf">Technical Fact Sheet–Tungsten</a>, accessed 27 March 2016.</li>
<li><a href="/facts/United_States_Government/VJCxUaf7">United States Government</a> 2014, <a href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title40-vol29/xml/CFR-2014-title40-vol29-sec401-15.xml">Toxic Pollutant List</a>, Code of Federal Regulations, 40 CFR 401.15., accessed 27 March 2016.</li>
<li>Valkovic V. 1990, "Origin of trace element requirements by living matter", in B. Gruber & J. H. Yopp (eds), Symmetries in Science IV: Biological and biophysical systems, Plenum Press, New York, pp. 213–242, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-4612-7884-9.</li>
<li>VanGelder K. T. 2014, Fundamentals of Automotive Technology: Principles and Practice, <a href="/facts/Jones_%2526_Bartlett_Learning/Bz6vdDg8">Jones & Bartlett Learning</a>, Burlington MA, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-4496-7108-2.</li>
<li>Venner M., Lessening M., Pankani D. & Strecker E. 2004, <a href="http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_521.pdf">Identification of Research Needs Related to Highway Runoff Management</a>, <a href="/facts/Transportation_Research_Board/8w5oPeIG">Transportation Research Board</a>, Washington DC, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-309-08815-2, accessed 21 August 2016.</li>
<li>Venugopal B. & Luckey T. D. 1978, Metal Toxicity in Mammals, vol. 2, Plenum Press, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-306-37177-6.</li>
<li>Vernon R. E. 2013, "Which elements are metalloids", Journal of Chemical Education, vol. 90, no. 12, pp. 1703–1707, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1021%2Fed3008457">10.1021/ed3008457</a>.</li>
<li>Volesky B. 1990, Biosorption of Heavy Metals, CRC Press, Boca Raton, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-8493-4917-1.</li>
<li>von Gleich A. 2013, "Outlines of a sustainable metals industry", in A. von Gleich, R. U. Ayres & S. Gößling-Reisemann (eds), Sustainable Metals Management, Springer, Dordrecht, pp. 3–40, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-4020-4007-8.</li>
<li>von Zeerleder A. 1949, Technology of Light Metals, Elsevier Publishing Company, New York.</li>
<li>Warth A. H. 1956, The Chemistry and Technology of Waxes, Reinhold Publishing Corporation, New York.</li>
<li><a href="/facts/Spencer_R._Weart/312ryym8">Weart S. R.</a> 1983, "The discovery of nuclear fission and a nuclear physics paradigm", in W. Shea (ed.), Otto Hahn and the Rise of Nuclear Physics, <a href="/facts/D._Reidel/GStj4ADP">D. Reidel</a> Publishing Company, Dordrecht, pp. 91–133, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-90-277-1584-5.</li>
<li>Weber D. J. & Rutula W. A. 2001, "Use of metals as microbicides in preventing infections in healthcare", in Disinfection, Sterilization, and Preservation, 5th ed., S. S. Block (ed.), <a href="/facts/Lippincott%2c_Williams_%2526_Wilkins/5kwRHTut">Lippincott, Williams & Wilkins</a>, Philadelphia, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-683-30740-5.</li>
<li>Welter G. 1976, Cleaning and Preservation of Coins and Medals, S. J. Durst, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-915262-03-8.</li>
<li>White C. 2010, Projectile Dynamics in Sport: Principles and Applications, <a href="/facts/Routledge/aSwcES11">Routledge</a>, London, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-415-47331-6.</li>
<li>Wiberg N. 2001, Inorganic Chemistry, Academic Press, San Diego, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-12-352651-9.</li>
<li>Wijayawardena M. A. A., Megharaj M. & Naidu R. 2016, "Exposure, toxicity, health impacts and bioavailability of heavy metal mixtures", in D. L. Sparks, Advances in Agronomy, vol. 138, pp. 175–234, Academic Press, London, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-12-804774-3.</li>
<li>Wingerson L. 1986, "<a href="https://books.google.com/books?id=qfak8nsMNGIC&pg=PA35">America cleans up Liberty</a>[permanent dead link]", New Scientist, 25 December/1 January 1987, pp. 31–35, accessed 1 October 2016.</li>
<li>Wong M. Y., Hedley G. J., Xie G., Kölln L. S, Samuel I. D. W., Pertegaś A., Bolink H. J., Mosman-Colman, E., "Light-emitting electrochemical cells and solution-processed organic light-emitting diodes using small molecule organic thermally activated delayed fluorescence emitters", <a href="/facts/Chemistry_of_Materials/Ps5Sxk41">Chemistry of Materials</a>, vol. 27, no. 19, pp. 6535–6542, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1021%2Facs.chemmater.5b03245">10.1021/acs.chemmater.5b03245</a>.</li>
<li>Wulfsberg G. 1987, Principles of Descriptive Inorganic Chemistry, <a href="/facts/Cengage_Learning/Bda6bYXT">Brooks/Cole Publishing Company</a>, Monterey, California, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-534-07494-4.</li>
<li>Wulfsberg G. 2000, Inorganic Chemistry, University Science Books, Sausalito, California, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-891389-01-6.</li>
<li>Yadav J. S., Antony A., Subba Reddy, B. V. 2012, "Bismuth(III) salts as synthetic tools in organic transformations", in T. Ollevier (ed.), Bismuth-mediated Organic Reactions, Topics in Current Chemistry 311, Springer, Heidelberg, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3-642-27238-7.</li>
<li>Yang D. J., Jolly W. L. & O'Keefe A. 1977, "Conversion of hydrous germanium(II) oxide to germynyl sesquioxide, (HGe)2O3", <a href="/facts/Inorganic_Chemistry_(journal)/yEeLo9Na">'Inorganic Chemistry</a>, vol. 16, no. 11, pp.  2980–2982, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1021%2Fic50177a070">10.1021/ic50177a070</a>.</li>
<li>Yousif N. 2007, Geochemistry of stream sediment from the state of Colorado using NURE data, ETD Collection for the University of Texas, El Paso, <a href="http://digitalcommons.utep.edu/dissertations/AAI3273991">paper AAI3273991</a>.</li></ul>

<h2 id="further-reading">Further reading</h2>
Definition and usage

<ul><li>Ali H. & Khan E. 2017, "What are heavy metals? Long-standing controversy over the scientific use of the term 'heavy metals'—proposal of a comprehensive definition", Toxicological & Environmental Chemistry, pp. 1–25, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1080%2F02772248.2017.1413652">10.1080/02772248.2017.1413652</a>. Suggests defining heavy metals as "naturally occurring metals having atomic number (Z) greater than 20 and an elemental density greater than 5 g cm−3".</li>
<li><a href="http://www.duffus.com/jhduffus1940.htm">Duffus J. H.</a> 2002, "<a href="http://www.iupac.org/publications/pac/2002/pdf/7405x0793.pdf">'Heavy metals'—A meaningless term?"</a>, Pure and Applied Chemistry, vol. 74, no. 5, pp. 793–807, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1351%2Fpac200274050793">10.1351/pac200274050793</a>. Includes a survey of the term's various meanings.</li>
<li>Hawkes S. J. 1997, "<a href="http://pubs.acs.org/doi/abs/10.1021/ed074p1374">What is a 'heavy metal'?</a>", Journal of Chemical Education, vol. 74, no. 11, p. 1374, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1021%2Fed074p1374">10.1021/ed074p1374</a>. A chemist's perspective.</li>
<li>Hübner R., Astin K. B. & Herbert R. J. H. 2010, "'Heavy metal'—time to move on from semantics to pragmatics?", <a href="/facts/Journal_of_Environmental_Monitoring/s6Cg3pAp">Journal of Environmental Monitoring</a>, vol. 12, pp. 1511–1514, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1039%2FC0EM00056F">10.1039/C0EM00056F</a>. Finds that, despite its lack of specificity, the term appears to have become part of the language of science.</li></ul>
Toxicity and biological role

<ul><li>Baird C. & Cann M. 2012, Environmental Chemistry, 5th ed., chapter 12, "Toxic heavy metals", <a href="/facts/W._H._Freeman_and_Company/sJ3zg32G">W. H. Freeman and Company</a>, New York, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 1-4292-7704-1. Discusses the use, toxicity, and distribution of Hg, Pb, Cd, As, and Cr.</li>
<li>Nieboer E. & Richardson D. H. S. 1980, "The replacement of the nondescript term 'heavy metals' by a biologically and chemically significant classification of metal ions", Environmental Pollution Series B, Chemical and Physical, vol. 1, no. 1, pp. 3–26, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1016%2F0143-148X%2880%2990017-8">10.1016/0143-148X(80)90017-8</a>. A widely cited paper, focusing on the biological role of heavy metals.</li>
<li><a href="https://www.mdpi.com/2076-3921/11/12/2467">Association between Heavy Metal Exposure and Parkinson’s Disease: A Review of the Mechanisms Related to Oxidative Stress</a>.</li></ul>
Formation

<ul><li>Hadhazy A. 2016, "<a href="http://www.kavlifoundation.org/science-spotlights/cosmic-heavy-metals#.V4MEDleO7OY">Galactic 'gold mine' explains the origin of nature's heaviest elements</a> <a href="https://web.archive.org/web/20160524101329/http://www.kavlifoundation.org/science-spotlights/cosmic-heavy-metals#.V4MEDleO7OY">Archived</a> 2016-05-24 at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a>", Science Spotlights, 10 May, accessed 11 July 2016</li></ul>
Uses

<ul><li>Koehler C. S. W. 2001, "<a href="http://pubs.acs.org/subscribe/archive/tcaw/10/i01/html/01chemch.html">Heavy metal medicine</a>", Chemistry Chronicles, American Chemical Society, accessed 11 July 2016</li>
<li>Morowitz N. 2006, "The heavy metals", Modern Marvels, season 12, episode 14, <a href="/facts/History_(U.S._TV_channel)/jLIIsuhg">HistoryChannel.com</a></li>
<li>Öhrström L. 2014, "<a href="http://www.rsc.org/periodic-table/element/73/tantalum#podcast">Tantalum oxide</a>", Chemistry World, 24 September, accessed 4 October 2016. The author explains how tantalum(V) oxide banished brick-sized mobile phones. Also available as a <a href="http://www.rsc.org/periodic-table/podcast/73/tantalum">podcast</a>.</li></ul>
<h2 id="external-links">External links</h2>
<ul><li> Media related to Heavy metals at Wikimedia Commons</li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1">Duffus 2002. <a href="#fnref:1" class="footnote-back-ref">↩</a></li>
<li id="fn:2">Pourret, Olivier; Bollinger, Jean-Claude; Hursthouse, Andrew (2021). "Heavy metal: a misused term?" (PDF). Acta Geochimica. 40 (3): 466–471. Bibcode:2021AcGch..40..466P. doi:10.1007/s11631-021-00468-0. S2CID 232342843.Clegg 2014 <a href="https://hal.archives-ouvertes.fr/hal-03174937/file/Heavy%20Metal%20March%202021.pdf" target="_blank">https://hal.archives-ouvertes.fr/hal-03174937/file/Heavy%20Metal%20March%202021.pdf</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></li>
<li id="fn:3">Hübner, Astin & Herbert 2010 <a href="#fnref:3" class="footnote-back-ref">↩</a></li>
<li id="fn:4">Duffus 2002. <a href="#fnref:4" class="footnote-back-ref">↩</a></li>
<li id="fn:5">Duffus 2002, p. 795. <a href="#fnref:5" class="footnote-back-ref">↩</a></li>
<li id="fn:6">Ali & Khan 2018. - Ali H, Khan E (2018-01-02). "What are heavy metals? Long-standing controversy over the scientific use of the term 'heavy metals' – proposal of a comprehensive definition". Toxicological & Environmental Chemistry. 100 (1): 6–19. Bibcode:2018TxEC..100....6A. doi:10.1080/02772248.2017.1413652. ISSN 0277-2248. <a href="https://www.tandfonline.com/doi/full/10.1080/02772248.2017.1413652" target="_blank">https://www.tandfonline.com/doi/full/10.1080/02772248.2017.1413652</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></li>
<li id="fn:7">Nieboer & Richardson 1980. <a href="#fnref:7" class="footnote-back-ref">↩</a></li>
<li id="fn:8">Baldwin & Marshall 1999. <a href="#fnref:8" class="footnote-back-ref">↩</a></li>
<li id="fn:9">Goyer & Clarkson 1996, p. 839. - Goyer RA, Clarkson TW (1996). "Toxic effects of metals". Casarett and Doull's toxicology: the basic science of poisons 5. McGraw-Hill. <a href="#fnref:9" class="footnote-back-ref">↩</a></li>
<li id="fn:10">Duffus 2002, p. 795. <a href="#fnref:10" class="footnote-back-ref">↩</a></li>
<li id="fn:11">Pourret, Bollinger & Hursthouse 2021. - Pourret, Olivier; Bollinger, Jean-Claude; Hursthouse, Andrew (2021). "Heavy metal: a misused term?" (PDF). Acta Geochimica. 40 (3): 466–471. Bibcode:2021AcGch..40..466P. doi:10.1007/s11631-021-00468-0. S2CID 232342843. <a href="https://hal.archives-ouvertes.fr/hal-03174937/file/Heavy%20Metal%20March%202021.pdf" target="_blank">https://hal.archives-ouvertes.fr/hal-03174937/file/Heavy%20Metal%20March%202021.pdf</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></li>
<li id="fn:12">Hübner, Astin & Herbert 2010, p. 1513 <a href="#fnref:12" class="footnote-back-ref">↩</a></li>
<li id="fn:13">Rainbow 1991, p. 416 <a href="#fnref:13" class="footnote-back-ref">↩</a></li>
<li id="fn:14">Pourret, Bollinger & Hursthouse 2021. - Pourret, Olivier; Bollinger, Jean-Claude; Hursthouse, Andrew (2021). "Heavy metal: a misused term?" (PDF). Acta Geochimica. 40 (3): 466–471. Bibcode:2021AcGch..40..466P. doi:10.1007/s11631-021-00468-0. S2CID 232342843. <a href="https://hal.archives-ouvertes.fr/hal-03174937/file/Heavy%20Metal%20March%202021.pdf" target="_blank">https://hal.archives-ouvertes.fr/hal-03174937/file/Heavy%20Metal%20March%202021.pdf</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></li>
<li id="fn:15">Nieboer & Richardson 1980, p. 21 <a href="#fnref:15" class="footnote-back-ref">↩</a></li>
<li id="fn:16">Morris 1992, p. 1001 <a href="#fnref:16" class="footnote-back-ref">↩</a></li>
<li id="fn:17">Gorbachev, Zamyatnin & Lbov 1980, p. 5 <a href="#fnref:17" class="footnote-back-ref">↩</a></li>
<li id="fn:18">Hawkes 1997 <a href="#fnref:18" class="footnote-back-ref">↩</a></li>
<li id="fn:19">Duffus 2002, p. 798 <a href="#fnref:19" class="footnote-back-ref">↩</a></li>
<li id="fn:20">Duffus 2002, p. 798 <a href="#fnref:20" class="footnote-back-ref">↩</a></li>
<li id="fn:21">Rand, Wells & McCarty 1995, p. 23 <a href="#fnref:21" class="footnote-back-ref">↩</a></li>
<li id="fn:22">Baldwin & Marshall 1999, p. 267 <a href="#fnref:22" class="footnote-back-ref">↩</a></li>
<li id="fn:23">Lyman 2003, p. 452 <a href="#fnref:23" class="footnote-back-ref">↩</a></li>
<li id="fn:24">Duffus 2002, p. 797 <a href="#fnref:24" class="footnote-back-ref">↩</a></li>
<li id="fn:25">Liens 2010, p. 1415 <a href="#fnref:25" class="footnote-back-ref">↩</a></li>
<li id="fn:26">Criteria used were density:[17] (1) above 3.5 g/cm3; (2) above 7 g/cm3; atomic weight: (3) > 22.98;[17] (4) > 40 (excluding s- and f-block metals);[18] (5) > 200;[19] atomic number: (6) > 20; (7) 21–92;[20] chemical behaviour: (8) United States Pharmacopeia;[23][24][25] (9) Hawkes' periodic table-based definition (excluding the lanthanides and actinides);[16] and (10) Nieboer and Richardson's biochemical classifications.[26] Densities of the elements are mainly from Emsley.[27] Predicted densities have been used for At, Fr and Fm–Ts.[28] Indicative densities were derived for Fm, Md, No and Lr based on their atomic weights, estimated metallic radii,[29] and predicted close-packed crystalline structures.[30] Atomic weights are from Emsley,[27] inside back cover <a href="#fnref:26" class="footnote-back-ref">↩</a></li>
<li id="fn:27">Vernon 2013, p. 1703 <a href="#fnref:27" class="footnote-back-ref">↩</a></li>
<li id="fn:28">Metalloids were, however, excluded from Hawkes' periodic table-based definition given he noted it was "not necessary to decide whether semimetals [i.e. metalloids] should be included as heavy metals."[16] <a href="#fnref:28" class="footnote-back-ref">↩</a></li>
<li id="fn:29">The United States Pharmacopeia 1985, p. 1189 <a href="#fnref:29" class="footnote-back-ref">↩</a></li>
<li id="fn:30">Hawkes 1997 <a href="#fnref:30" class="footnote-back-ref">↩</a></li>
<li id="fn:31">Nieboer & Richardson 1980, p. 5 <a href="#fnref:31" class="footnote-back-ref">↩</a></li>
<li id="fn:32">Nieboer & Richardson 1980, pp. 6–7 <a href="#fnref:32" class="footnote-back-ref">↩</a></li>
<li id="fn:33">Nieboer & Richardson 1980, p. 9 <a href="#fnref:33" class="footnote-back-ref">↩</a></li>
<li id="fn:34">Rainbow 1991, p. 416 <a href="#fnref:34" class="footnote-back-ref">↩</a></li>
<li id="fn:35">Hübner, Astin & Herbert 2010, pp. 1511–1512 <a href="#fnref:35" class="footnote-back-ref">↩</a></li>
<li id="fn:36">Raymond 1984, pp. 8–9 <a href="#fnref:36" class="footnote-back-ref">↩</a></li>
<li id="fn:37">Habashi 2009, p. 31 <a href="#fnref:37" class="footnote-back-ref">↩</a></li>
<li id="fn:38">Gmelin 1849, p. 2 <a href="#fnref:38" class="footnote-back-ref">↩</a></li>
<li id="fn:39">Magee 1969, p. 14 <a href="#fnref:39" class="footnote-back-ref">↩</a></li>
<li id="fn:40">The Minerals, Metals and Materials Society 2016 <a href="#fnref:40" class="footnote-back-ref">↩</a></li>
<li id="fn:41">Emsley 2011, pp. 35, passim <a href="#fnref:41" class="footnote-back-ref">↩</a></li>
<li id="fn:42">Lead, a cumulative poison, has a relatively high abundance due to its extensive historical use and human-caused discharge into the environment.[42] <a href="/wiki/Bioaccumulation" target="_blank">/wiki/Bioaccumulation</a> <a href="#fnref:42" class="footnote-back-ref">↩</a></li>
<li id="fn:43">Haynes shows an amount of < 17 mg for tin[43] <a href="#fnref:43" class="footnote-back-ref">↩</a></li>
<li id="fn:44">Iyengar records a figure of 5 mg for nickel;[44] Haynes shows an amount of 10 mg[43]
 <a href="#fnref:44" class="footnote-back-ref">↩</a></li>
<li id="fn:45">Selenium is a nonmetal. <a href="#fnref:45" class="footnote-back-ref">↩</a></li>
<li id="fn:46">Encompassing 45 heavy metals occurring in quantities of less than 10 mg each, including As (7 mg), Mo (5), Co (1.5), and Cr (1.4)[45] <a href="#fnref:46" class="footnote-back-ref">↩</a></li>
<li id="fn:47">Emsley 2011, pp. 604, 31, 133, 358, 47, 475 <a href="#fnref:47" class="footnote-back-ref">↩</a></li>
<li id="fn:48">Valkovic 1990, pp. 214, 218 <a href="#fnref:48" class="footnote-back-ref">↩</a></li>
<li id="fn:49">Emsley 2011, pp. 331, 89, 552 <a href="#fnref:49" class="footnote-back-ref">↩</a></li>
<li id="fn:50">Emsley 2011, p. 571 <a href="#fnref:50" class="footnote-back-ref">↩</a></li>
<li id="fn:51">Venugopal & Luckey 1978, p. 307 <a href="#fnref:51" class="footnote-back-ref">↩</a></li>
<li id="fn:52">Emsley 2011, pp. 24, passim <a href="#fnref:52" class="footnote-back-ref">↩</a></li>
<li id="fn:53">Of the elements commonly recognised as metalloids, B and Si were counted as nonmetals; Ge, As, Sb, and Te as heavy metals. <a href="#fnref:53" class="footnote-back-ref">↩</a></li>
<li id="fn:54">Emsley 2011, pp. 192, 197, 240, 120, 166, 188, 224, 269, 299, 423, 464, 549, 614, 559 <a href="#fnref:54" class="footnote-back-ref">↩</a></li>
<li id="fn:55">Duffus 2002, pp. 794, 799 <a href="#fnref:55" class="footnote-back-ref">↩</a></li>
<li id="fn:56">Baird & Cann 2012, p. 519 <a href="#fnref:56" class="footnote-back-ref">↩</a></li>
<li id="fn:57">Kozin & Hansen 2013, p. 80 <a href="#fnref:57" class="footnote-back-ref">↩</a></li>
<li id="fn:58">Baird & Cann 2012, pp. 519–520, 567; Rusyniak et al. 2010, p. 387 <a href="#fnref:58" class="footnote-back-ref">↩</a></li>
<li id="fn:59">Di Maio 2001, p. 208 <a href="#fnref:59" class="footnote-back-ref">↩</a></li>
<li id="fn:60">Perry & Vanderklein 1996, p. 208 <a href="#fnref:60" class="footnote-back-ref">↩</a></li>
<li id="fn:61">Love 1998, p. 208 <a href="#fnref:61" class="footnote-back-ref">↩</a></li>
<li id="fn:62">Hendrickson 2016, p. 42 <a href="#fnref:62" class="footnote-back-ref">↩</a></li>
<li id="fn:63">Reyes 2007, pp. 1, 20, 35–36 <a href="#fnref:63" class="footnote-back-ref">↩</a></li>
<li id="fn:64">Emsley 2011, p. 311 <a href="#fnref:64" class="footnote-back-ref">↩</a></li>
<li id="fn:65">Wiberg 2001, pp. 1474, 1501 <a href="#fnref:65" class="footnote-back-ref">↩</a></li>
<li id="fn:66">Tokar et al. 2013 <a href="#fnref:66" class="footnote-back-ref">↩</a></li>
<li id="fn:67">Eisler 1993, pp. 3, passim <a href="#fnref:67" class="footnote-back-ref">↩</a></li>
<li id="fn:68">Lemly 1997, p. 259; Ohlendorf 2003, p. 490 <a href="#fnref:68" class="footnote-back-ref">↩</a></li>
<li id="fn:69">State Water Control Resources Board 1987, p. 63 <a href="#fnref:69" class="footnote-back-ref">↩</a></li>
<li id="fn:70">Scott 1989, pp. 107–108 <a href="#fnref:70" class="footnote-back-ref">↩</a></li>
<li id="fn:71">International Antimony Association 2016 <a href="#fnref:71" class="footnote-back-ref">↩</a></li>
<li id="fn:72">Tokar et al. 2013 <a href="#fnref:72" class="footnote-back-ref">↩</a></li>
<li id="fn:73">Ni, Cu, Zn, Se, Ag and Sb appear in the United States Government's Toxic Pollutant List;[70] Mn, Co, and Sn are listed in the Australian Government's National Pollutant Inventory.[71] <a href="#fnref:73" class="footnote-back-ref">↩</a></li>
<li id="fn:74">Tokar et al. 2013 <a href="#fnref:74" class="footnote-back-ref">↩</a></li>
<li id="fn:75">Cole & Stuart 2000, p. 315 <a href="#fnref:75" class="footnote-back-ref">↩</a></li>
<li id="fn:76">Pourret, Olivier; Bollinger, Jean-Claude; Hursthouse, Andrew (2021). "Heavy metal: a misused term?" (PDF). Acta Geochimica. 40 (3): 466–471. Bibcode:2021AcGch..40..466P. doi:10.1007/s11631-021-00468-0. S2CID 232342843.Clegg 2014 <a href="https://hal.archives-ouvertes.fr/hal-03174937/file/Heavy%20Metal%20March%202021.pdf" target="_blank">https://hal.archives-ouvertes.fr/hal-03174937/file/Heavy%20Metal%20March%202021.pdf</a> <a href="#fnref:76" class="footnote-back-ref">↩</a></li>
<li id="fn:77">Emsley 2011, p. 240 <a href="#fnref:77" class="footnote-back-ref">↩</a></li>
<li id="fn:78">Tokar et al. 2013 <a href="#fnref:78" class="footnote-back-ref">↩</a></li>
<li id="fn:79">Emsley 2011, p. 595 <a href="#fnref:79" class="footnote-back-ref">↩</a></li>
<li id="fn:80">Namla, Djadjiti; Mangse, George; Koleoso, Peter O.; Ogbaga, Chukwuma C.; Nwagbara, Onyinye F. (2022). "Assessment of Heavy Metal Concentrations of Municipal Open-Air Dumpsite: A Case Study of Gosa Dumpsite, Abuja". Innovations and Interdisciplinary Solutions for Underserved Areas. Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering. Vol. 449. pp. 165–174. doi:10.1007/978-3-031-23116-2_13. ISBN 978-3-031-23115-5. <a href="978-3-031-23115-5" target="_blank">978-3-031-23115-5</a> <a href="#fnref:80" class="footnote-back-ref">↩</a></li>
<li id="fn:81">Stankovic & Stankovic 2013, pp. 154–159 <a href="#fnref:81" class="footnote-back-ref">↩</a></li>
<li id="fn:82">Ndiokwere, C.L. (January 1984). "A study of heavy metal pollution from motor vehicle emissions and its effect on roadside soil, vegetation and crops in Nigeria". Environmental Pollution Series B, Chemical and Physical. 7 (1): 35–42. doi:10.1016/0143-148X(84)90035-1. <a href="https://linkinghub.elsevier.com/retrieve/pii/0143148X84900351" target="_blank">https://linkinghub.elsevier.com/retrieve/pii/0143148X84900351</a> <a href="#fnref:82" class="footnote-back-ref">↩</a></li>
<li id="fn:83">https://blog.nationalgeographic.org/2015/08/03/heavy-metals-in-motor-oil-have-heavy-consequences/ Heavy Metals in Motor Oil Have Heavy Consequences <a href="https://blog.nationalgeographic.org/2015/08/03/heavy-metals-in-motor-oil-have-heavy-consequences/" target="_blank">https://blog.nationalgeographic.org/2015/08/03/heavy-metals-in-motor-oil-have-heavy-consequences/</a> <a href="#fnref:83" class="footnote-back-ref">↩</a></li>
<li id="fn:84">"Fear In The Fields -- How Hazardous Wastes Become Fertilizer -- Spreading Heavy Metals On Farmland Is Perfectly Legal, But Little Research Has Been Done To Find Out Whether It's Safe". <a href="https://archive.seattletimes.com/archive/?date=19970703&slug=2547772" target="_blank">https://archive.seattletimes.com/archive/?date=19970703&slug=2547772</a> <a href="#fnref:84" class="footnote-back-ref">↩</a></li>
<li id="fn:85">https://hazwastehelp.org/ArtHazards/glassworking.aspx Art Hazards <a href="https://hazwastehelp.org/ArtHazards/glassworking.aspx" target="_blank">https://hazwastehelp.org/ArtHazards/glassworking.aspx</a> <a href="#fnref:85" class="footnote-back-ref">↩</a></li>
<li id="fn:86">Wang, P.; Hu, Y.; Cheng, H. (2019). "Municipal solid waste (MSW) incineration fly ash as an important source of heavy metal pollution in China". Environmental Pollution. 252 (Pt A): 461–475. Bibcode:2019EPoll.252..461W. doi:10.1016/j.envpol.2019.04.082. PMID 31158674. S2CID 145832923. <a href="https://pubmed.ncbi.nlm.nih.gov/31158674/" target="_blank">https://pubmed.ncbi.nlm.nih.gov/31158674/</a> <a href="#fnref:86" class="footnote-back-ref">↩</a></li>
<li id="fn:87">Bradl 2005, pp. 15, 17–20 <a href="#fnref:87" class="footnote-back-ref">↩</a></li>
<li id="fn:88">Harvey, Handley & Taylor 2015, p. 12276 <a href="#fnref:88" class="footnote-back-ref">↩</a></li>
<li id="fn:89">Howell et al. 2012; Cole et al. 2011, pp. 2589–2590 <a href="#fnref:89" class="footnote-back-ref">↩</a></li>
<li id="fn:90">Amasawa et al. 2016, pp. 95–101 <a href="#fnref:90" class="footnote-back-ref">↩</a></li>
<li id="fn:91">Massarani 2015 <a href="#fnref:91" class="footnote-back-ref">↩</a></li>
<li id="fn:92">Torrice 2016 <a href="#fnref:92" class="footnote-back-ref">↩</a></li>
<li id="fn:93">Trace elements having an abundance much less than the one part per trillion of Ra and Pa (namely Tc, Pm, Po, At, Ac, Np, and Pu) are not shown. Abundances are from Lide[89] and Emsley;[90] occurrence types are from McQueen.[91] <a href="/wiki/Radium" target="_blank">/wiki/Radium</a> <a href="#fnref:93" class="footnote-back-ref">↩</a></li>
<li id="fn:94">Cox 1997, pp. 73–89 <a href="#fnref:94" class="footnote-back-ref">↩</a></li>
<li id="fn:95">Cox 1997, pp. 32, 63, 85 <a href="#fnref:95" class="footnote-back-ref">↩</a></li>
<li id="fn:96">Podosek 2011, p. 482 <a href="#fnref:96" class="footnote-back-ref">↩</a></li>
<li id="fn:97">Cox 1997, pp. 73–89 <a href="#fnref:97" class="footnote-back-ref">↩</a></li>
<li id="fn:98">Padmanabhan 2001, p. 234 <a href="#fnref:98" class="footnote-back-ref">↩</a></li>
<li id="fn:99">In some cases, for example in the presence of high energy gamma rays or in a very high temperature hydrogen rich environment, the subject nuclei may experience neutron loss or proton gain resulting in the production of (comparatively rare) neutron deficient isotopes.[96] <a href="/wiki/Photodisintegration" target="_blank">/wiki/Photodisintegration</a> <a href="#fnref:99" class="footnote-back-ref">↩</a></li>
<li id="fn:100">Hofmann 2002, pp. 23–24 <a href="#fnref:100" class="footnote-back-ref">↩</a></li>
<li id="fn:101">Hadhazy 2016 <a href="#fnref:101" class="footnote-back-ref">↩</a></li>
<li id="fn:102">The ejection of matter when two neutron stars collide is attributed to the interaction of their tidal forces, possible crustal disruption, and shock heating (which is what happens if you floor the accelerator in a car when the engine is cold).[99] <a href="/wiki/Tidal_force" target="_blank">/wiki/Tidal_force</a> <a href="#fnref:102" class="footnote-back-ref">↩</a></li>
<li id="fn:103">Cox 1997, pp. 83, 91, 102–103 <a href="#fnref:103" class="footnote-back-ref">↩</a></li>
<li id="fn:104">Lide 2004, pp. 14–17 <a href="#fnref:104" class="footnote-back-ref">↩</a></li>
<li id="fn:105">Berry & Mason 1959, pp. 210–211; Rankin 2011, p. 69 <a href="#fnref:105" class="footnote-back-ref">↩</a></li>
<li id="fn:106">Hartmann 2005, p. 197 <a href="#fnref:106" class="footnote-back-ref">↩</a></li>
<li id="fn:107">Yousif 2007, pp. 11–12 <a href="#fnref:107" class="footnote-back-ref">↩</a></li>
<li id="fn:108">Berry & Mason 1959, p. 214 <a href="#fnref:108" class="footnote-back-ref">↩</a></li>
<li id="fn:109">Yousif 2007, p. 11 <a href="#fnref:109" class="footnote-back-ref">↩</a></li>
<li id="fn:110">Wiberg 2001, p. 1511 <a href="#fnref:110" class="footnote-back-ref">↩</a></li>
<li id="fn:111">Iron, cobalt, nickel, germanium and tin are also siderophiles from a whole of Earth perspective.[91] <a href="#fnref:111" class="footnote-back-ref">↩</a></li>
<li id="fn:112">Emsley 2011, p. 403 <a href="#fnref:112" class="footnote-back-ref">↩</a></li>
<li id="fn:113">Litasov & Shatskiy 2016, p. 27 <a href="#fnref:113" class="footnote-back-ref">↩</a></li>
<li id="fn:114">Sanders 2003; Preuss 2011 <a href="#fnref:114" class="footnote-back-ref">↩</a></li>
<li id="fn:115">Heat escaping from the inner solid core is believed to generate motion in the outer core, which is made of liquid iron alloys. The motion of this liquid generates electrical currents which give rise to a magnetic field.[110] <a href="#fnref:115" class="footnote-back-ref">↩</a></li>
<li id="fn:116">MacKay, MacKay & Henderson 2002, pp. 203–204 <a href="#fnref:116" class="footnote-back-ref">↩</a></li>
<li id="fn:117">Heavy metals that occur naturally in quantities too small to be economically mined (Tc, Pm, Po, At, Ac, Np and Pu) are instead produced by artificial transmutation.[112] The latter method is also used to produce heavy metals from americium onwards.[113] <a href="/wiki/Nuclear_transmutation" target="_blank">/wiki/Nuclear_transmutation</a> <a href="#fnref:117" class="footnote-back-ref">↩</a></li>
<li id="fn:118">Emsley 2011, p. 437 <a href="#fnref:118" class="footnote-back-ref">↩</a></li>
<li id="fn:119">Chen & Huang 2006, p. 208; Crundwell et al. 2011, pp. 411–413; Renner et al. 2012, p. 332; Seymour & O'Farrelly 2012, pp. 10–12 <a href="#fnref:119" class="footnote-back-ref">↩</a></li>
<li id="fn:120">Crundwell et al. 2011, p. 409 <a href="#fnref:120" class="footnote-back-ref">↩</a></li>
<li id="fn:121">International Platinum Group Metals Association n.d., pp. 3–4 <a href="#fnref:121" class="footnote-back-ref">↩</a></li>
<li id="fn:122">McLemore 2008, p. 44 <a href="#fnref:122" class="footnote-back-ref">↩</a></li>
<li id="fn:123">Wiberg 2001, p. 1277 <a href="#fnref:123" class="footnote-back-ref">↩</a></li>
<li id="fn:124">Jones 2001, p. 3 <a href="#fnref:124" class="footnote-back-ref">↩</a></li>
<li id="fn:125">Berea, Rodriguez-lbelo & Navarro 2016, p. 203 <a href="#fnref:125" class="footnote-back-ref">↩</a></li>
<li id="fn:126">Alves, Berutti & Sánchez 2012, p. 94 <a href="#fnref:126" class="footnote-back-ref">↩</a></li>
<li id="fn:127">Yadav, Antony & Subba Reddy 2012, p. 231 <a href="#fnref:127" class="footnote-back-ref">↩</a></li>
<li id="fn:128">Masters 1981, p. 5 <a href="#fnref:128" class="footnote-back-ref">↩</a></li>
<li id="fn:129">Wulfsberg 1987, pp. 200–201 <a href="#fnref:129" class="footnote-back-ref">↩</a></li>
<li id="fn:130">Bryson & Hammond 2005, p. 120 (high electron density); Frommer & Stabulas-Savage 2014, pp. 69–70 (high atomic number) <a href="#fnref:130" class="footnote-back-ref">↩</a></li>
<li id="fn:131">Landis, Sofield & Yu 2011, p. 269 <a href="#fnref:131" class="footnote-back-ref">↩</a></li>
<li id="fn:132">Emsley 2011, p. 286 <a href="#fnref:132" class="footnote-back-ref">↩</a></li>
<li id="fn:133">Berger & Bruning 1979, p. 173 <a href="#fnref:133" class="footnote-back-ref">↩</a></li>
<li id="fn:134">Jackson & Summitt 2006, pp. 10, 13 <a href="#fnref:134" class="footnote-back-ref">↩</a></li>
<li id="fn:135">Shedd 2002, p. 80.5; Kantra 2001, p. 10 <a href="#fnref:135" class="footnote-back-ref">↩</a></li>
<li id="fn:136">Spolek 2007, p. 239 <a href="#fnref:136" class="footnote-back-ref">↩</a></li>
<li id="fn:137">White 2010, p. 139 <a href="#fnref:137" class="footnote-back-ref">↩</a></li>
<li id="fn:138">Dapena & Teves 1982, p. 78 <a href="#fnref:138" class="footnote-back-ref">↩</a></li>
<li id="fn:139">Burkett 2010, p. 80 <a href="#fnref:139" class="footnote-back-ref">↩</a></li>
<li id="fn:140">Moore & Ramamoorthy 1984, p. 102 <a href="#fnref:140" class="footnote-back-ref">↩</a></li>
<li id="fn:141">National Materials Advisory Board 1973, p. 58 <a href="#fnref:141" class="footnote-back-ref">↩</a></li>
<li id="fn:142">Livesey 2012, p. 57 <a href="#fnref:142" class="footnote-back-ref">↩</a></li>
<li id="fn:143">VanGelder 2014, pp. 354, 801 <a href="#fnref:143" class="footnote-back-ref">↩</a></li>
<li id="fn:144">National Materials Advisory Board 1971, pp. 35–37 <a href="#fnref:144" class="footnote-back-ref">↩</a></li>
<li id="fn:145">Frick 2000, p. 342 <a href="#fnref:145" class="footnote-back-ref">↩</a></li>
<li id="fn:146">National Materials Advisory Board 1973, p. 58 <a href="#fnref:146" class="footnote-back-ref">↩</a></li>
<li id="fn:147">Rockhoff 2012, p. 314 <a href="#fnref:147" class="footnote-back-ref">↩</a></li>
<li id="fn:148">Russell & Lee 2005, pp. 16, 96 <a href="#fnref:148" class="footnote-back-ref">↩</a></li>
<li id="fn:149">Morstein 2005, p. 129 <a href="#fnref:149" class="footnote-back-ref">↩</a></li>
<li id="fn:150">Russell & Lee 2005, pp. 218–219 <a href="#fnref:150" class="footnote-back-ref">↩</a></li>
<li id="fn:151">Lach et al. 2015; Di Maio 2016, p. 154 <a href="#fnref:151" class="footnote-back-ref">↩</a></li>
<li id="fn:152">Preschel 2005; Guandalini et al. 2011, p. 488 <a href="#fnref:152" class="footnote-back-ref">↩</a></li>
<li id="fn:153">Weber & Rutula 2001, p. 415 <a href="#fnref:153" class="footnote-back-ref">↩</a></li>
<li id="fn:154">Dunn 2009; Bonetti et al. 2009, pp. 1, 84, 201 <a href="#fnref:154" class="footnote-back-ref">↩</a></li>
<li id="fn:155">Desoize 2004, p. 1529 <a href="#fnref:155" class="footnote-back-ref">↩</a></li>
<li id="fn:156">Atlas 1986, p. 359; Lima et al. 2013, p. 1 <a href="#fnref:156" class="footnote-back-ref">↩</a></li>
<li id="fn:157">Volesky 1990, p. 174 <a href="#fnref:157" class="footnote-back-ref">↩</a></li>
<li id="fn:158">Nakbanpote, Meesungnoen & Prasad 2016, p. 180 <a href="#fnref:158" class="footnote-back-ref">↩</a></li>
<li id="fn:159">Emsley 2011, pp. 447, 74, 384, 123 <a href="#fnref:159" class="footnote-back-ref">↩</a></li>
<li id="fn:160">Elliot 1946, p. 11; Warth 1956, p. 571 <a href="#fnref:160" class="footnote-back-ref">↩</a></li>
<li id="fn:161">Emsley 2011, pp. 135, 313, 141, 495, 626, 479, 630, 334, 495, 556, 424, 339, 169, 571, 252, 205, 286, 599 <a href="#fnref:161" class="footnote-back-ref">↩</a></li>
<li id="fn:162">Everts 2016 <a href="#fnref:162" class="footnote-back-ref">↩</a></li>
<li id="fn:163">Emsley 2011, p. 450 <a href="#fnref:163" class="footnote-back-ref">↩</a></li>
<li id="fn:164">Emsley 2011, p. 334 <a href="#fnref:164" class="footnote-back-ref">↩</a></li>
<li id="fn:165">Moselle 2004, pp. 409–410 <a href="#fnref:165" class="footnote-back-ref">↩</a></li>
<li id="fn:166">Russell & Lee 2005, p. 323 <a href="#fnref:166" class="footnote-back-ref">↩</a></li>
<li id="fn:167">Tretkoff 2006 <a href="#fnref:167" class="footnote-back-ref">↩</a></li>
<li id="fn:168">Emsley 2011, pp. 73, 141, 141, 141, 355, 73, 424, 340, 189, 189 <a href="#fnref:168" class="footnote-back-ref">↩</a></li>
<li id="fn:169">Baranoff 2015, p. 80; Wong et al. 2015, p. 6535 <a href="#fnref:169" class="footnote-back-ref">↩</a></li>
<li id="fn:170">Tisza 2001, p. 73 <a href="#fnref:170" class="footnote-back-ref">↩</a></li>
<li id="fn:171">Chandler & Roberson 2009, pp. 47, 367–369, 373; Ismail, Khulbe & Matsuura 2015, p. 302 <a href="#fnref:171" class="footnote-back-ref">↩</a></li>
<li id="fn:172">Ebbing & Gammon 2017, p. 695 <a href="#fnref:172" class="footnote-back-ref">↩</a></li>
<li id="fn:173">Pan & Dai 2015, p. 69 <a href="#fnref:173" class="footnote-back-ref">↩</a></li>
<li id="fn:174">Brown 1987, p. 48 <a href="#fnref:174" class="footnote-back-ref">↩</a></li>
</ol>

Heavy metals open-in-new

Heavy metals