Polynuclear Aromatic Hydrocarbons

Abstract

CONTENTS 22.1 Introduction ................................................................................................................... 580 22.2 Chemistry of PAHs ...................................................................................................... 580 22.3 Sources of PAHs ........................................................................................................... 581 22.4 Occurrence ..................................................................................................................... 582 22.5 Toxicity ........................................................................................................................... 582 22.6 Genotoxicity ................................................................................................................... 583 22.7 Carcinogenicity.............................................................................................................. 584 22.8 Carcinogenesis of PAHs .............................................................................................. 585 22.9 Effect of PAH Exposure to Humans ......................................................................... 586 22.10 Toxicokinetics ................................................................................................................ 587 22.10.1 Absorption..................................................................................................... 587 22.10.2 Distribution ................................................................................................... 587 22.10.3 Metabolism.................................................................................................... 587 22.10.4 Excretion........................................................................................................ 588 22.11 Structure-Activity Relationship ................................................................................. 588 22.12 Biomarkers of Exposure to PAHs .............................................................................. 589 22.13 Analysis of PAHs.......................................................................................................... 589 22.13.1 Extraction of PAHs ...................................................................................... 590 22.13.2 Sample Cleanup ........................................................................................... 590 22.13.3 Quality Assurance/Quality Control of Sample Collection.................... 591 22.13.4 Recovery Studies .......................................................................................... 591 22.13.5 Chromatographic Separation of PAHs..................................................... 592 22.13.6 Gas Chromatography in the Analysis of PAHs...................................... 592 22.13.7 High-Performance Liquid Chromatography in the Analysis of PAHs......................................................................................... 593 22.13.8 Micellar Electrokinetic Capillary Chromatography in the Analysis of PAHs ............................................................................. 593 22.13.9 Use of Internal Standards ........................................................................... 593 References ................................................................................................................................... 595 Polynuclear aromatic hydrocarbons (PAHs) are a class of diverse organic compounds containing two or more fused aromatic rings of carbon and hydrogen atoms. They are ubiquitous environmental contaminants found in air, water, and soil [1-4]. Hundreds of PAHs have been identified and these are usually found as complex mixtures of individual compounds [5]. PAHs comprise the largest class of chemical compounds known to be cancer-causing agents and are included in the European Union and United States Environmental Protection Agency (EPA) priority pollutant list due to their mutagenic and carcinogenic properties [6]. Some compounds, while not carcinogenic, may act as synergists [7]. At ambient temperatures, PAHs are colorless to yellow solids. The general characteristics common to the class are their high melting and boiling points, low vapor pressures, low water solubility, and high lipid solubility; their water solubility tends to decrease with increasing molecular mass.