PAHs have received increased attention in recent years in air pollution studies because some of these compounds are highly carcinogenic or mutagenic (IARC 1983). PAH refers to a group of a few hundreds of compounds with two or more fused benzene rings. PAHs from fuel oils tend to be quickly adsorbed onto particles and to accumulate in sediments (Tolosa et al. Their fate is determined by their physico-chemical properties, especially nonpolarity and hydrophobicity responsible for their persistence in the environment. Natural sources such as forest fires and volcanic eruptions are less important. 2002), while the use of heating sources can increase PAH concentrations in indoor air (WHO 1987). Additional contributions to ambient air levels arise from tobacco smoking (Sakai et al. PAHs are also occurring in large amounts in sedimentary rocks and petroleum (Lichtfouse et al. Sources of PAHs in urban atmosphere include automobiles, re-suspended soils, refineries and power plants (Omar et al. 2002) and stationary combustion sources or crematoria (Santasiero et al. Other possible sources are tire wear debris, asphalt particles (Binet et al. Therefore vehicular emissions may not be the only source of PAHs in these samples. Polycyclic aromatic hydrocarbons (PAHs) from incomplete combustion or pyrolysis organic material sources are ubiquitous in the global environment and are typically more concentrated near urban centers (Hyötyläinen and Oikari 2004). Emphasis in this review will, therefore, be placed on the use of bioaccumulation and biomarker responses in air, soil, water and food, as monitoring tools for the assessment of the risks and hazards of PAH concentrations for the ecosystem, as well as on its limitations. bioaccumulation) as well as pollution-induced biological and biochemical effects on human organisms to evaluate or predict the impact of chemicals on ecosystems. As it well known, there is an increasing trend to use the behavior of pollutants (i.e. The scope of this review will be to give an overview of PAH concentrations in various environmental samples and to discuss the advantages and limitations of applying these parameters in the assessment of environmental risks in ecosystems and human health. Thus, exposure assessments of PAHs in the developing world are important. The US Environmental Protection Agency (EPA) has promulgated 16 unsubstituted PAHs (EPA-PAH) as priority pollutants. In particular, benzo(a)pyrene has been identified as being highly carcinogenic. Eight PAHs (Car-PAHs) typically considered as possible carcinogens are: benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene (B(a)P), dibenzo(a,h)anthracene, indeno(1,2,3-cd)pyrene and benzo(g,h,i)perylene. PAHs have received increased attention in recent years in air pollution studies because some of these compounds are highly carcinogenic or mutagenic. The occurrence is largely a result of anthropogenic emissions such as fossil fuel-burning, motor vehicle, waste incinerator, oil refining, coke and asphalt production, and aluminum production, etc. PAHs are widespread environmental contaminants resulting from incomplete combustion of organic materials. PAHs may also be degraded by some microorganisms in the soil. In the atmosphere, PAHs can react with pollutants such as ozone, nitrogen oxides and sulfur dioxide, yielding diones, nitro- and dinitro-PAHs, and sulfonic acids, respectively. When dissolved in water or adsorbed on particulate matter, PAHs can undergo photodecomposition when exposed to ultraviolet light from solar radiation. Most of the PAHs with low vapour pressure in the air are adsorbed on particles. They have a relatively low solubility in water, but are highly lipophilic.
Polycyclic aromatic hydrocarbons (PAHs) are a large group of organic compounds with two or more fused aromatic rings.