Aromatic compounds, also known as "mono- and polycyclic aromatic hydrocarbons", are organic compounds containing one or more aromatic rings. The word "aromatic" originates from the past grouping of molecules based on odor, before their general chemical properties were understood. The current definition of aromatic compounds does not have any relation with their odor.
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.
Tar is the name for the resinous, combusted particulate matter made by the burning of tobacco and other plant material in the act of smoking. Tar is toxic and damages the smoker's lungs over time through various biochemical and mechanical processes. Tar also damages the mouth by rotting and blackening teeth, damaging gums, and desensitizing taste buds. Tar includes the majority of mutagenic and carcinogenic agents in tobacco smoke. Polycyclic aromatic hydrocarbons (PAH), for example, are genotoxic and epoxidative.
Mycoremediation is a form of bioremediation in which fungi-based remediation methods are used to decontaminate the environment. Fungi have been proven to be a cheap, effective and environmentally sound way for removing a wide array of contaminants from damaged environments or wastewater. These contaminants include heavy metals, organic pollutants, textile dyes, leather tanning chemicals and wastewater, petroleum fuels, polycyclic aromatic hydrocarbons, pharmaceuticals and personal care products, pesticides and herbicides in land, fresh water, and marine environments.
Retene, methyl isopropyl phenanthrene or 1-methyl-7-isopropyl phenanthrene, C18H18, is a polycyclic aromatic hydrocarbon present in the coal tar fraction, boiling above 360 °C. It occurs naturally in the tars obtained by the distillation of resinous woods. It crystallizes in large plates, which melt at 98.5 °C and boil at 390 °C. It is readily soluble in warm ether and in hot glacial acetic acid. Sodium and boiling amyl alcohol reduce it to a tetrahydroretene, but if it heated with phosphorus and hydriodic acid to 260 °C, a dodecahydride is formed. Chromic acid oxidizes it to retene quinone, phthalic acid and acetic acid. It forms a picrate that melts at 123-124 °C.
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.
The PAH world hypothesis is a speculative hypothesis that proposes that polycyclic aromatic hydrocarbons (PAHs), known to be abundant in the universe, including in comets, and assumed to be abundant in the primordial soup of the early Earth, played a major role in the origin of life by mediating the synthesis of RNA molecules, leading into the RNA world. However, as yet, the hypothesis is untested.
Delftia is a genus of Gram-negative bacteria that was first isolated from soil in Delft, Netherlands. The species is named after both the city, and in honor of pioneering research in the field of bacteriology that occurred in Delft. Cells in the genus Delftia are rod shaped and straight or slightly curved. Cells occur singly or in pairs, are 0.4–0.8ɥM wide and 2.5–4.1 μm long. Delftia species are motile by flagella, nonsporulating, and chemo-organotrophic.
Unresolved complex mixture (UCM), or hump, is a feature frequently observed in gas chromatographic (GC) data of crude oils and extracts from organisms exposed to oil.
1H-Phenalene, often called simply phenalene is a polycyclic aromatic hydrocarbon (PAH). Like many PAHs, it is an atmospheric pollutant formed during the combustion of fossil fuels. It is the parent compound for the phosphorus-containing phosphaphenalenes.
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.
The environmental impact of the petroleum industry is extensive and expansive due to petroleum having many uses. Crude oil and natural gas are primary energy and raw material sources that enable numerous aspects of modern daily life and the world economy. Their supply has grown quickly over the last 150 years to meet the demands of the rapidly increasing human population, creativity, knowledge, and consumerism.
Dibenzopyrenes are a group of high molecular weight polycyclic aromatic hydrocarbons with the molecular formula C24H14. There are five isomers of dibenzopyrene which differ by the arrangement of aromatic rings: dibenzo[a,e]pyrene, dibenzo[a,h]pyrene, dibenzo[a,i]pyrene, dibenzo[a,l]pyrene, and dibenzo[e,l]pyrene.
Bioremediation of petroleum contaminated environments is a process in which the biological pathways within microorganisms or plants are used to degrade or sequester toxic hydrocarbons, heavy metals, and other volatile organic compounds found within fossil fuels. Oil spills happen frequently at varying degrees along with all aspects of the petroleum supply chain, presenting a complex array of issues for both environmental and public health. While traditional cleanup methods such as chemical or manual containment and removal often result in rapid results, bioremediation is less labor-intensive, expensive, and averts chemical or mechanical damage. The efficiency and effectiveness of bioremediation efforts are based on maintaining ideal conditions, such as pH, RED-OX potential, temperature, moisture, oxygen abundance, nutrient availability, soil composition, and pollutant structure, for the desired organism or biological pathway to facilitate reactions. Three main types of bioremediation used for petroleum spills include microbial remediation, phytoremediation, and mycoremediation. Bioremediation has been implemented in various notable oil spills including the 1989 Exxon Valdez incident where the application of fertilizer on affected shoreline increased rates of biodegradation.
Bioremediation is the process of decontaminating polluted sites through the usage of either endogenous or external microorganism. In situ is a term utilized within a variety of fields meaning "on site" and refers to the location of an event. Within the context of bioremediation, in situ indicates that the location of the bioremediation has occurred at the site of contamination without the translocation of the polluted materials. Bioremediation is used to neutralize pollutants including Hydrocarbons, chlorinated compounds, nitrates, toxic metals and other pollutants through a variety of chemical mechanisms. Microorganism used in the process of bioremediation can either be implanted or cultivated within the site through the application of fertilizers and other nutrients. Common polluted sites targeted by bioremediation are groundwater/aquifers and polluted soils. Aquatic ecosystems affected by oil spills have also shown improvement through the application of bioremediation. The most notable cases being the Deepwater Horizon oil spill in 2010 and the Exxon Valdez oil spill in 1989. Two variations of bioremediation exist defined by the location where the process occurs. Ex situ bioremediation occurs at a location separate from the contaminated site and involves the translocation of the contaminated material. In situ occurs within the site of contamination In situ bioremediation can further be categorized by the metabolism occurring, aerobic and anaerobic, and by the level of human involvement.
Roy Michael Harrison is a British environmental scientist. He has been Queen Elizabeth II Birmingham Centenary Professor of Environmental Health at the University of Birmingham since 1991, and is a distinguished adjunct professor at King Abdulaziz University in Jeddah, Saudi Arabia.
In organic chemistry, contorted aromatics, or more precisely contorted polycyclic aromatic hydrocarbons, are polycyclic aromatic hydrocarbons (PAHs) in which the fused aromatic molecules deviate from the usual planarity.
Passive sampling is an environmental monitoring technique involving the use of a collecting medium, such as a man-made device or biological organism, to accumulate chemical pollutants in the environment over time. This is in contrast to grab sampling, which involves taking a sample directly from the media of interest at one point in time. In passive sampling, average chemical concentrations are calculated over a device's deployment time, which avoids the need to visit a sampling site multiple times to collect multiple representative samples. Currently, passive samplers have been developed and deployed to detect toxic metals, pesticides, pharmaceuticals, radionuclides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and other organic compounds in water, while some passive samplers can detect hazardous substances in the air.
Sally Katharine Hammond is a Professor of Environmental Health Sciences and Associate Dean of Academic Affairs at the UC Berkeley School of Public Health. Her research considers the impact of pollution and passive smoking on public health. It resulted in the Federal Aviation Administration issuing a ban on smoking on aeroplanes. Hammond serves on the World Health Organization study group on Tobacco Product Regulation.
