Coal tar is a thick dark liquid which is a by-product of the production of coke and coal gas from coal. It is a type of creosote. It has both medical and industrial uses. Medicinally it is a topical medication applied to skin to treat psoriasis and seborrheic dermatitis (dandruff). It may be used in combination with ultraviolet light therapy. Industrially it is a railroad tie preservative and used in the surfacing of roads. Coal tar was listed as a known human carcinogen in the first Report on Carcinogens from the U.S. Federal Government, issued in 1980.
Naphthalene is an organic compound with formula C
10H
8. It is the simplest polycyclic aromatic hydrocarbon, and is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings. It is the main ingredient of traditional mothballs.
Anthracene is a solid polycyclic aromatic hydrocarbon (PAH) of formula C14H10, consisting of three fused benzene rings. It is a component of coal tar. Anthracene is used in the production of the red dye alizarin and other dyes. Anthracene is colorless but exhibits a blue (400–500 nm peak) fluorescence under ultraviolet radiation.
Soot is a mass of impure carbon particles resulting from the incomplete combustion of hydrocarbons. It is more properly restricted to the product of the gas-phase combustion process but is commonly extended to include the residual pyrolysed fuel particles such as coal, cenospheres, charred wood, and petroleum coke that may become airborne during pyrolysis and that are more properly identified as cokes or char.
Phenanthrene is a polycyclic aromatic hydrocarbon (PAH) with formula C14H10, consisting of three fused benzene rings. It is a colorless, crystal-like solid, but can also appear yellow. Phenanthrene is used to make dyes, plastics and pesticides, explosives and drugs. It has also been used to make bile acids, cholesterol and steroids.
A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. The simplest representative is naphthalene, having two aromatic rings, and the three-ring compounds anthracene and phenanthrene. PAHs are uncharged, non-polar and planar. Many are colorless. Many of them are found in coal and in oil deposits, and are also produced by the incomplete combustion of organic matter—for example, in engines and incinerators or when biomass burns in forest fires.
Benzo[a]pyrene (BaP or B[a]P) is a polycyclic aromatic hydrocarbon and the result of incomplete combustion of organic matter at temperatures between 300 °C (572 °F) and 600 °C (1,112 °F). The ubiquitous compound can be found in coal tar, tobacco smoke and many foods, especially grilled meats. The substance with the formula C20H12 is one of the benzopyrenes, formed by a benzene ring fused to pyrene. Its diol epoxide metabolites, more commonly known as BPDE, react with and bind to DNA, resulting in mutations and eventually cancer. It is listed as a Group 1 carcinogen by the IARC. In the 18th century a scrotal cancer of chimney sweepers, the chimney sweeps' carcinoma, was already known to be connected to soot.
IARC group 2A agents are substances and exposure circumstances that have been classified as probable carcinogens by the International Agency for Research on Cancer (IARC). This designation is applied when there is limited evidence of carcinogenicity in humans, as well as sufficient evidence of carcinogenicity in experimental animals. In some cases, an agent may be classified in this group when there is inadequate evidence of carcinogenicity in humans along with sufficient evidence of carcinogenicity in experimental animals and strong evidence that the carcinogenesis is mediated by a mechanism that also operates in humans. Exceptionally, an agent may be classified in this group solely on the basis of limited evidence of carcinogenicity in humans.
Fluoranthene is a polycyclic aromatic hydrocarbon (PAH). The molecule can be viewed as the fusion of naphthalene and benzene unit connected by a five-membered ring. Although samples are often pale yellow, the compound is colorless. It is soluble in nonpolar organic solvents. It is a member of the class of PAHs known as non-alternant PAHs because it has rings other than those with six carbon atoms. It is a structural isomer of the alternant PAH pyrene. It is not as thermodynamically stable as pyrene. Its name is derived from its fluorescence under UV light.
Occupational lung diseases comprise a broad group of diseases, including occupational asthma, industrial bronchitis, chronic obstructive pulmonary disease (COPD), bronchiolitis obliterans, inhalation injury, interstitial lung diseases, infections, lung cancer and mesothelioma. These can be caused directly or due to immunological response to an exposure to a variety of dusts, chemicals, proteins or organisms. Occupational cases of interstitial lung disease may be misdiagnosed as COPD, idiopathic pulmonary fibrosis, or a myriad of other diseases; leading to a delay in identification of the causative agent.
In molecular genetics, a DNA adduct is a segment of DNA bound to a cancer-causing chemical. This process could lead to the development of cancerous cells, or carcinogenesis. DNA adducts in scientific experiments are used as biomarkers of exposure. They are especially useful in quantifying an organism's exposure to a carcinogen. The presence of such an adduct indicates prior exposure to a potential carcinogen, but it does not necessarily indicate the presence of cancer in the subject animal.
Chrysene is a polycyclic aromatic hydrocarbon (PAH) with the molecular formula C
18H
12 that consists of four fused benzene rings. It is a natural constituent of coal tar, from which it was first isolated and characterized. It is also found in creosote at levels of 0.5–6 mg/kg.
Sir Ernest Laurence Kennaway FRS was a British pathologist and Royal Medal winner. He first became interested in natural life when, due to a childhood illness, he was encouraged to spend time outdoors. He was trained at University College London, and in 1898 was accepted into New College, Oxford on an open scholarship to study natural sciences. He graduated with a B.A. in 1903, and after three years at Middlesex Hospital he completed a Bachelor of Medicine and Surgery. After graduating he worked for The Lister Institute for Preventive Medicine and UCL before returning to Oxford, this time to Brasenose College on a Hulme scholarship in 1909. He became a Travelling Fellow of Brasenose in 1910, a Doctor of Medicine in 1911 and a Doctor of Science in 1915.
Anthanthrene is a polycyclic aromatic hydrocarbon. According to the International Agency for Research on Cancer, as of 2006 there was "limited evidence in experimental animals" that it is a carcinogen.
Chlorinated polycyclic aromatic hydrocarbons (Cl-PAHs) are a group of compounds comprising polycyclic aromatic hydrocarbons with two or more aromatic rings and one or more chlorine atoms attached to the ring system. Cl-PAHs can be divided into two groups: chloro-substituted PAHs, which have one or more hydrogen atoms substituted by a chlorine atom, and chloro-added Cl-PAHs, which have two or more chlorine atoms added to the molecule. They are products of incomplete combustion of organic materials. They have many congeners, and the occurrences and toxicities of the congeners differ. Cl-PAHs are hydrophobic compounds and their persistence within ecosystems is due to their low water solubility. They are structurally similar to other halogenated hydrocarbons such as polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs). Cl-PAHs in the environment are strongly susceptible to the effects of gas/particle partitioning, seasonal sources, and climatic conditions.
A benzopyrene is an organic compound with the formula C20H12. Structurally speaking, the colorless isomers of benzopyrene are pentacyclic hydrocarbons and are fusion products of pyrene and a phenylene group. Two isomeric species of benzopyrene are benzo[a]pyrene and the less common benzo[e]pyrene. They belong to the chemical class of polycyclic aromatic hydrocarbons.
Benzo[j]fluoranthene (BjF) is an organic compound with the chemical formula C20H12. Classified as a polycyclic aromatic hydrocarbon (PAH), it is a colourless solid that is poorly soluble in most solvents. Impure samples can appear off white. Closely related isomeric compounds include benzo[a]fluoranthene (BaF), bendo[b]fluoranthene (BbF), benzo[e]fluoranthene (BeF), and benzo[k]fluoranthene (BkF). BjF is present in fossil fuels and is released during incomplete combustion of organic matter. It has been traced in the smoke of cigarettes, exhaust from gasoline engines, emissions from the combustion of various types of coal and emissions from oil heating, as well as an impurity in some oils such as soybean oil.
Dibenz[a,h]anthracene or Benzo[k]tetraphene or 1,2:5,6-Dibenzanthracene is an organic compound with the chemical formula C22H14. It is a polycyclic aromatic hydrocarbon (PAH) made of five fused benzene rings. It is a fused five-ringed PAH which is common as a pollutant of smoke and oils. It is stable and highly genotoxic in bacterial and mammalian cell systems, as it intercalates into DNA and causes mutations.
Benzo[c]fluorene is a polycyclic aromatic hydrocarbon (PAH) with mutagenic activity. It is a component of coal tar, cigarette smoke and smog and thought to be a major contributor to its carcinogenic properties. The mutagenicity of benzo[c]fluorene is mainly attributed to formation of metabolites that are reactive and capable of forming DNA adducts. According to the KEGG it is a group 3 carcinogen. Other names for benzo[c]fluorene are 7H-benzo[c]fluorene, 3,4-benzofluorene, and NSC 89264.
Indeno[1,2,3-cd]pyrene is a polycyclic aromatic hydrocarbon (PAH), one of 16 PAHs generally measured in studies of environmental exposure and air pollution. Many compounds of this class are formed when burning coal, oil, gas, wood, household waste and tobacco, and can bind to or form small particles in the air. The compounds are known to have toxic, mutagenic and/or carcinogenic properties. Over 100 different PAHs have been identified in environmental samples. One of these 16 is Indeno[1,2,3-cd]pyrene (IP). IP is the combination of an indeno molecule and a pyrene molecule with a fluoranthene network. In 1962, the National Cancer Institute reported that indeno[1,2,3-cd]pyrene has a slight tumor activity. This was confirmed in 1973 by the IARC in mice testing.
