Monitoring and Risk Analysis of PAHs in the Environment

• Published in: Handbook of Environmental Materials Management pp. 973 - 1007
• Main Authors: Hussain, Karishma, Hoque, Raza R., Balachandran, Srinivasan, Medhi, Subhash, Idris, Mohammad Ghaznavi, Rahman, Mirzanur, Hussain, Farhaz Liaquat
• Format: Book Chapter
• Language: English
• Published: Cham Springer International Publishing
• Subjects: Carcinogenicity; Ecosystem risk; Ecotoxic Effects; Polycyclic aromatic hydrocarbon; Toxicity
• ISBN: 3319736442; 9783319736440
• DOI: 10.1007/978-3-319-73645-7_29

Polycyclic aromatic hydrocarbons (PAHs) are a unique class of organic pollutants containing two or more fused aromatic rings, which are toxic and potential carcinogens. They are extensively studied compounds, and their occurrence has been reported from various places over the world which indicates their ubiquitous nature in our environment. Anthropogenic sources of PAHs are more dominant than their natural source which include sources like combustion engines, residential heating, industrial activities, and biomass burning. USEPA has already listed 16 PAHs [naphthalene, acenaphthylene, acenaphthene, fluorine, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perylene, and indeno(1,2,3-c,d)pyrene] as most priority ones to be analyzed in various environmental matrices. More so, benzo(a)pyrene is termed as index or gold standard of the whole group of PAHs due to its high carcinogenic potency. Once in the atmosphere, depending on their physical and chemical properties, PAHs get distributed between gas, particle, and droplet phase. Aerial movement is one of the major pathways for environmental distribution and transboundary deposition of PAHs. Eventually, PAHs settle down in soils and street dust and enter into aquatic environment. Soil and street dust act as direct sink of atmospheric PAHs near to traffic and other combustion sources. From these environmental compartments, rainwater and storm water easily wash away PAHs to nearby aquatic bodies. Due to hydrophobic nature, PAHs in aquatic environment are preferably partitioned and accumulate into the particulate phase of sediment. PAHs, thus, occur in multicompartmental system of the environment and paved the way for multiple routes of exposure to this class of carcinogen. Therefore, extensive studies have been carried out for PAHs in different environmental matrices over the world, and many places are revealed with very high exposure levels of PAHs. Environmental PAHs have harmful effects on different types of organisms of the ecosystem. PAHs attract considerable attention among researchers due to continuous rise in death toll of human cancer worldwide. Toxic equivalency factors (TEFs) were often employed to assess carcinogenic potential of individual PAHs. Here, the maximum TEF of one is assigned to BaP, and other individual PAHs are relative to BaP as BaP equivalents (BaPq). To characterize risk of PAHs to surrounding organisms and ecosystems in aquatic environment, ecosystem risk was often employed by researchers by using risk quotient (RQ) of individual PAHs. Risk quotients (RQ) value indicated the levels of risk posed by certain PAHs. Studies are revealed with high exposure risk in different environmental matrices in several places around the world. However, only a few recommendations or guidelines exist worldwide for concentration of PAHs.