Benzoapyrene
<p ><b>Benzo[<i>a</i>]pyrene</b> is a <a href="http://en.wikipedia.org/wiki/Polycyclic_aromatic_hydrocarbon" title="Polycyclic aromatic hydrocarbon" >polycyclic aromatic hydrocarbon</a> found in <a href="http://en.wikipedia.org/wiki/Coal_tar" title="Coal tar" >coal tar</a> with the formula C<sub >20</sub>H<sub >12</sub>. Its metabolites are <a href="http://en.wikipedia.org/wiki/Mutagen" title="Mutagen" >mutagenic</a> and highly <a href="http://en.wikipedia.org/wiki/Carcinogen" title="Carcinogen" >carcinogenic</a>, and it is listed as a <a href="http://en.wikipedia.org/wiki/List_of_IARC_Group_1_carcinogens" title="List of IARC Group 1 carcinogens" >Group 1 carcinogen</a> by the <a href="http://en.wikipedia.org/wiki/International_Agency_for_Research_on_Cancer" title="International Agency for Research on Cancer" >IARC</a>. The compound is one of the <a href="http://en.wikipedia.org/wiki/Benzopyrene" title="Benzopyrene" >benzopyrenes</a>, formed by a <a href="http://en.wikipedia.org/wiki/Benzene" title="Benzene" >benzene</a> ring fused to <a href="http://en.wikipedia.org/wiki/Pyrene" title="Pyrene" >pyrene</a>, and is the result of incomplete combustion at temperatures between 300 °C (572 °F)and 600 °C (1,112 °F).</p>
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<a href="http://en.wikipedia.org/wiki/Chimney_sweep" title="Chimney sweep" >Chimney sweeps</a> suffered from <a href="http://en.wikipedia.org/wiki/Soot_wart" title="Soot wart" class="mw-redirect" >scrotal cancers</a> in the 18th century, and frequent <a href="http://en.wikipedia.org/wiki/Skin_cancer" title="Skin cancer" >skin cancers</a> were noted among fuel industry workers in the 19th century. In 1933, benzo[<i>a</i>]pyrene was determined to be the compound responsible for these cases, and its toxicity was demonstrated when skin tumors occurred in laboratory animals repeatedly painted with coal tar. When the body attempts to metabolise benzo[<i>a</i>]pyrene, the resulting diol epoxide reacts and binds to DNA, resulting in mutations and eventually cancer.</p>
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The most important source of human exposure is fatty food of animal origin (see Human intake, above).<sup id="cite_ref-Liem_28-2" class="reference" ><a href="http://en.wikipedia.org/wiki/Dioxins_and_dioxin-like_compounds#cite_note-Liem-28" >[29]</a></sup> There is quite a lot of variation between different countries as to the most important items. In U.S. and Central Europe milk and dairy products and meat have been by far the most important sources. In some countries, notably in Finland and to some extent in Sweden, fish is important due to contaminated Baltic fish and very low intake from any other sources.<sup id="cite_ref-synopsis_0-14" class="reference" ><a href="http://en.wikipedia.org/wiki/Dioxins_and_dioxin-like_compounds#cite_note-synopsis-0" >[1]</a></sup> In most countries a significant decrease of dioxin intake has occurred due to stricter controls during the last 20 years.</p>