API Publ 4714-2002 pdf free download

API Publ 4714-2002 pdf free download.A Guide to Polycyclic Aromatic Hydrocarbons for the Non-Specialist.
0 Overview This report provides an introduction to polycyclic aromatic hydrocarbons (PAHs) for persons working in the petroleum industry. It describes what PAHs are and how they are formed; PAH environmental transport, fate, and health effects; regulatory requirements related to PAHs; and analytical methods for measuring PAH concentrations in the environment. This information is of particular relevance to the petroleum industry due to the natural presence of PAHs in crude oil, the formation of PAHs during some refining processes, and the production of PAHs throughout the combustion of petroleum products. The intended audience for this report includes environmental professionals who must address PAH regulatory issues, and field personnel who are responsible for the sampling and analyses of PAHs. Concern about PAHs in the environment is due to their acute toxicity or carcinogenic properties, as well as their relative persistence. This concern has led to the regulation of PAHs under a number of U.S. laws, including the: • Clean Air Act (CAA), • Clean Water Act (CWA), • Emergency Planning and Community Right-to-Know Act (EPCRA), • Occupational Safety and Health Act (OSHA), • Resource Conservation and Recovery Act (RCRA), and • Safe Drinking Water Act (SDWA). Several environmental regulations relate directly to petroleum products or petroleum processing. Polycyclic organic matter (POM) is one of the toxic air pollutants whose emissions reformulated gasoline are meant to reduce. POM (defined as the sum of the seven carcinogenic PAHs) is also on the list of mobile source hazardous air pollutants that the EPA is proposing for future regulation, as well as on the list of hazardous air pollutants for the EPA’s Urban Air Toxics Strategy.
2 Sources of PAHs PAHs are produced in nature through four generalized pathways: 1) low temperature diagenesis of organic matter (part of the changes undergone by a sediment after its initial deposition); 2) the formation of petroleum and coal; 3) incomplete or inefficient combustion at moderate to high temperatures (pyrolysis); and, 4) biosynthesis by plants and animals. These processes are the primary sources of PAHs. Primary sources of PAHs also include anthropogenic (man-made) sources. These include the combustion of fossil fuels and biomass, such as wood, as well as chemical production that results in the formation of PAHs. Because the type distribution of PAHs depends on the temperature of formation, the characteristic distributions of these different sources can be used to help distinguish among different sources of PAHs in the environment. Once produced, PAHs are introduced or “delivered” into the environment through a number of pathways (i.e., secondary sources ), which are described in Section 3. 2.1 PRIMARY SOURCES OF PAHS Diagenic PAHs. Diagenic PAHs are those produced by natural processes that are set in motion when organic matter is deposited in nature—in soils or sediments. These processes, collectively called diagenesis, begin shortly after deposition of the organic matter. These are low temperature processes that occur after oxygen is depleted, and are believed to involve microorganisms, such as bacteria, though non-biological processes may occur in tandem. Relatively few individual PAHs are produced by these early diagenic processes. One of the most notable PAHs produced in this manner is the five-ringed PAH, perylene, shown in Figure 2-1. Perylene is commonly found in sediments of rivers, lakes, and oceans at a depth in the sediment where oxygen is reduced.
The types of PAHs formed as fossil fuels include a complex variety of parent (i.e., unsubstituted), and alkylated PAHs. Series of PAHs comprised of parent and substituted PAHs form many families or homologous series of PAHs. The phenanthrene homologous series of PAHs includes, for example, phenanthrene itself, plus a series of alkylated homologues of phenanthrene with many alkyl substitutions (see Figure 2-2). The relative abundance of the alkylated PAHs of petrogenic PAHs far exceeds the abundance of the parent (i.e. unsubstituted) compound or C 0 -phenanthrene. The fact that alkylated PAHs “are much greater than” parent PAHs is a main feature of petrogenic PAHs. This is illustrated in the first chart of Figure 2-3 for typical alkyl homologue distributions.