Polycyclic aromatic hydrocarbons environmental exposure

Pyrene is not classified as human carcinogen by the US Environmental Protection Agency (EPA) based on no human data and inadequate data from animal bioassays. Increased incidences of lung, skin, or genitourinary cancers were observed in workers exposed to a variety of polycyclic aromatic hydrocarbons. Prolonged exposure to coal tar pitch volatiles can cause dermatitis. 

Monteiro, P.R.R., Reis-Henriques, M.A., and Coimbra, J. (2000a). Plasma steroid levels in female flounder (Platichthys flesus) after chronic dietary exposure to single polycyclic aromatic hydrocarbons. Marine Environmental Research 49, 453 67. 

A wide variety of xenobiotics, such as polycyclic aromatic hydrocarbons or dioxins, are analyzed in human body fluids for the investigation of environmental and occupational exposure. 

Human exposure to complex mixtures of polycyclic aromatic hydrocarbons (PAH) occurs through inhalation of tobacco smoke and polluted indoor or outdoor air, through ingestion of certain foods and polluted water, and by dermal contact with soots, tars, and oils CO. Methylated PAH are always components of these mixtures and in some cases, as in tobacco smoke and in emissions from certain fuel processes, their concentrations can be in the same range as some unsubstituted PAH. The estimated emission of methylated PAH from mobile sources in the U.S. in 1979 was approximately 1700 metric tons (2). The occurrence of methylated and unsubstituted PAH has been recently reviewed (1, 2). In addition to their environmental occurrence, methylated PAH are among the most important model compounds in experimental carcinogenesis. 7,12-Dimethylbenz[a]anthracene, one of... 

Environmental chemicals and pollutants are also capable of inducing P450 enzymes. As previously noted, exposure to benzo[a]pyrene and other polycyclic aromatic hydrocarbons, which are present in tobacco smoke, charcoal-broiled meat, and other organic pyrolysis products, is known to induce CYP1A enzymes and to alter the rates of drug metabolism. Other environmental chemicals known to induce specific P450s include the polychlorinated biphenyls (PCBs), which were once used widely in industry as insulating materials and plasticizers, and 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin, TCDD), a trace byproduct of the chemical synthesis of the defoliant 2,4,5-T (see Chapter 56). 

Heitkamp, M. A. Cerniglia, C. E. (1987). The effects of chemical structure and exposure on the microbial degradation of polycyclic aromatic hydrocarbons in freshwater and estuarine ecosystems. Environmental Toxicology and Chemistry, 6, 535—46. 

Once the inhalation exposure questions have been identified, the specifications for each personal monitor must be determined and the monitor must be validated for the contaminant being measured. Table I, updated from Samet et al. (14), identifies currently available personal monitors, and Table II, taken from an Environmental Protection Agency (EPA) report (15), shows the projected needs in the 1990s. There are a number of opportunities for research on personal monitors Table II indicates that relatively few commercial units are currently available for either particulate or gas-phase species. For compounds such as polycyclic aromatic hydrocarbons (PAHs), a two-stage sampler is required because some PAHs exist simultaneously in the gaseous and particulate phase (16). Consequently, research must be ranked with respect to the significance of the air pollution problem, and the technological developments required to provide reliable samplers must be defined. 

Air quality is important from both a health and a safety perspective. In the USA, the National Institute for Occupational Safety and Health (NIOSH) and the Occupational Safety and Health Administration set limits of exposure to over 2000 different chemicals or classes of respiratory irritants [11, 12], Many of the compounds that are monitored indoors are of similar interest to outdoor assessment, such as in the atmosphere and stratosphere. VOCs emitted from industrial operations are continuously monitored as required by US and local Environmental Protection Agencies. Power plants and waste incinerators are required to follow emission guidelines for harmful combustion gases, including CO and NO, as well as other combustion by-products, including polycyclic aromatic hydrocarbons, phenols, and hy-... 

Perera, E.P., Rauh, V., et al (2006) Effect of prenatal exposure to airborne polycyclic aromatic hydrocarbons on neurodevelopment in the first 3 years of life among inner-city children. Environmental Health Perspectives, 114(8) 1287-1292. 

Singh, R., Sram, R.J., Binkova, B., Kalina, I., Popov, T.A., Georgieva, T., Garte, S., Taioli, E., Farmer, P.B. (2007). The relationship between biomarkers of oxidative DNA damage, polycyclic aromatic hydrocarbon DNA adducts, antioxidant status and genetic susceptibility following exposure to environmental air pollution in humans. Mutat. Res. 620 83-92. 

Benz [a] anthracene alone is not regulated however, all polycyclic aromatic hydrocarbons or volatile coal tar products together are regulated. The World Health Organization has established 0.2 pgH as the limit for aromatic hydrocarbons in a domestic water supply. The US Occupational Safety and Health Administration limit in workplace air (coal tar volatiles) is 0.2 mg m The US Environmental Protection Agency weight-of-evidence classification for benz [a] anthracene is B2, a probable human carcinogen, for both oral and inhalation exposure based on adequate animal evidence and no human evidence. 

Petty T, Schmid P, and Schlatter C (1996) The use of toxic equivalency factors in assessing occupational and environmental health science associated with exposure to air borne mixtures of polycyclic aromatic hydrocarbons. Chemosphere 32 639-648. 

HSPs as cellular markers of stress HSPs are involved in various aspects of cellular function and a lot is being learnt about its role in normal and pathological states. Recent studies from lower animals, especially fish, have revealed the potential use of induced fish HSPs as a biomarker of exposure to environmental stressors. Industrial effluents, polycyclic aromatic hydrocarbons, metals such as copper, zinc, mercury, pesticides, etc. have shown to induce HSP in fish. Further, the HSP response may vary with the stressor, tissue, species of fish, and the family of HSP studied. Hence it appears that a more extensive and probably a high-throughput profiling (using genomic and pro-teomic) approaches may be necessary to identify patterns of HSP modulation by various stressors. 

Boffetta P, Jourenkova N, Gustavsson P Cancer risk from occupational and environmental exposure to polycyclic aromatic hydrocarbons. Cancer Causes Control 1997 8 444-72. 

Evidence for health effects associated with exposure to smoke from combustion of biomass fuels was provided initially by studies on outdoor air pollution as well as by studies dealing with exposure to environmental tobacco smoke. Criteria documents for outdoor air pollutants published by the USEPA [ 13], for example, detail the effects of many components, including particulate matter, carbon monoxide, oxides of sulfur and nitrogen and polycyclic aromatic hydrocarbons. 

These experts collectively have knowledge of the polycyclic aromatic hydrocarbons physical and chemical properties, toxicokinetics, key health end points, mechanisms of action, human and animal exposure, and quantification of risk to humans. All reviewers were selected in conformity with the conditions for peer review specified in Section 104(i)(13) of the Comprehensive Environmental Response, Compensation, and Liability Act, as amended. 

This statement was prepared to give you information about polycyclic aromatic hydrocarbons (PAHs) and to emphasize the human health effects that may result from exposure to them. The Environmental Protection Agency (EPA) has identified 1,408 hazardous waste sites as the most serious in the nation. These sites make up the National Priorities List (NPL) and are the sites targeted for long-term federal clean-up activities. PAHs have been found in at least 600 of the sites on the NPL. However, the number of NPL sites evaluated for PAHs is not known. As EPA evaluates more sites, the number of sites at which PAHs are found may increase. This information is important because exposure to PAHs may cause harmful health effects and because these sites are potential or actual sources of human exposure to PAHs. 

Perwak J, Byrne M, Coons S, et al. 1982. An exposure and risk assessment for benzo[a]pyrene and other polycyclic aromatic hydrocarbons. Volume IV. Benzo[a]pyrene, acenaphthylene, benz[a]anthracene, benzo[b]fluoranthene, benzo[k]fluroanthene, benzo[g,h,i]perylene, chrysene, dibenz[a,h]anthracene, and indeno[1,2,3-c,d]pyrene. Washington, D.C. US Environmental Protection Agency, Office of Water Regulations and Standards. EPA 440/4-85-020-V4. 

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