1、 A Guide to Polycyclic Aromatic Hydrocarbons for the Non-SpecialistRegulatory and Scientific AffairsPUBLICATION NUMBER 4714FEBRUARY 2002A Guide to Polycyclic Aromatic Hydrocarbons for the Non-SpecialistRegulatory and Scientific AffairsAPI PUBLICATION NUMBER 4714FEBRUARY 2002PREPARED UNDER CONTRACT B
2、Y:Paul D. Boehm*, Christopher P. Loreti, Amy B. Rosenstein, and Phillip M. Rury*Arthur D. Little, Inc.Acorn ParkCambridge, Massachusetts02140-2390*Currently at Battelle Memorial Institute, Waltham, Massachusetts*Currently at Killam Associates, New England, Hadley, MassachusettsReference 69458FOREWOR
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9、t 2002 American Petroleum InstituteTABLE OF CONTENTSPageSection0 OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10、. . . . . . . 11.1 What are PAHs?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 SOURCES OF PAHS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22.1 Primary Sources of PAHs . . . . . . . .
11、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 PAHS IN THE ENVIRONMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43.1 PAH “Environmental Delivery Systems” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43.2 Overview of
12、 Concentrations in the Environment . . . . . . . . . . . . . . . . . . . . . . . . . 74 PAH TRANSPORT AND FATE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84.1 Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13、. . . . . . . . . . . 84.2 Fate Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 ENVIRONMENTAL AND HUMAN HEALTH EFFECTS. . . . . . . . . . . . . . . . . . . . 115.1 Sources of Human Exposure . . . . . . . . . . . . . . . . . . . . .
14、 . . . . . . . . . . . . . . . . . . . 115.2 Human Health Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125.2.1 Non-carcinogenic Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135.2.2 Carcinogenic Effects . . . . .
15、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145.2.3 Regulatory Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155.3 Ecological Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16、 155.3.1 Bioavailability and Uptake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165.3.2 Regulatory Standards Related to PAH Ecological Effects . . . . . . . . . . . 175.3.3 Guidance on Screening Methods for Ecological Effects . . . . . . . . . . . . 186 CHEMICAL ANALYSIS OF
17、 PAHS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196.1 PAH Analytical Goals and Targets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196.2 Analytical Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18、. . . . . 206.3 PAH Source Identification (Fingerprinting) and Allocation . . . . . . . . . . . . . . . . 226.4 Analytical Efficiency and Costs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22APPENDIX A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19、. . . . . . . . . . . . . . . . . . . . . . . . . . 25REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Figures2-1 Perylene, a Five-Ringed Diagenic PAH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20、 22-2 Phenanthrene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-3 Representative Distribution of Alkylated PAHs Formed atDifferent Temperatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21、. . . 32-4 Retene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43-1 PAHs in Alaska North Slope Crude Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65-1 Relative Doses of Carcinogenic PAHs . . . . . .
22、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136-1 Comparison of PAH Analyses with Two Different Target Lists . . . . . . . . . . . . . . 216-2 Schematic of Top-Level PAH Fingerprinting and Allocation Approach . . . . . . . . 23A-1 Structures of the 16 Priority Pollutant PAHs . . . . . .
23、 . . . . . . . . . . . . . . . . . . . . . . . 27iiiPageSectionTables5-1 Average Concentrations of Carcinogenic PAHs in Food, mg/kg . . . . . . . . . . . . . . 125-2 PAH Reference Doses for Non-Cancer Health Effects . . . . . . . . . . . . . . . . . . . . . 145-3 Slope Factors and EPA Classification
24、 for Carcinogenic PAHs . . . . . . . . . . . . . . . 155-4 Ambient Water Quality Criteria for PAHs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166-1 Extended Analytical Target List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206-2 Recommended Detec
25、tion Limits for PAHs in Environmental Samples . . . . . . . . 226-3 Approximate Costs for High Quality PAH Analyses Performed byExperienced Laboratories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23A-1 Physico-chemical Properties of Selected PAHs . . . .
26、. . . . . . . . . . . . . . . . . . . . . . . 27iv1A Guide to Polycyclic Aromatic Hydrocarbons for the Non-Specialist0 OverviewThis report provides an introduction to polycyclic aromatic hydrocarbons (PAHs) for persons working in the petroleumindustry. It describes what PAHs are and how they are for
27、med; 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, thefo
28、rmation of PAHs during some refining processes, and the production of PAHs throughout the combustion of petroleumproducts. The intended audience for this report includes environmental professionals who must address PAH regulatoryissues, and field personnel who are responsible for the sampling and an
29、alyses of PAHs.Concern about PAHs in the environment is due to their acute toxicity or carcinogenic properties, as well as their relativepersistence. 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 Plann
30、ing 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
31、 one of the toxic air pollutants whose emissions reformulated gasoline are meant to reduce. POM (defined as thesum of the seven carcinogenic PAHs) is also on the list of mobile source hazardous air pollutants that the EPA is proposingfor future regulation, as well as on the list of hazardous air pol
32、lutants for the EPAs Urban Air Toxics Strategy.Toxic release inventory reporting (TRI) under EPCRA requires facilities, such as oil refineries that manufacture, process, orotherwise use as little as 10 lbs of the PAH benzoghiperylene or 100 lbs of polycyclic aromatic compounds (a group of 21PAHs, su
33、bstituted PAHs, and heterocyclic compounds), to report their releases to the environment. Other laws andregulations on PAHs, which are described in Section 5 of this report, apply to their concentrations in the natural andworkplace environment. 1 Introduction1.1 WHAT ARE PAHS?Polycyclic aromatic hyd
34、rocarbons (PAHs)sometimes referred to as polynuclear aromatic hydrocarbons (PNAs),condensed ring aromatics, or fused ring aromaticsare a class of organic compounds consisting of two or more fusedaromatic rings.Naphthalene, consisting of two fused benzene rings, is the simplest PAH. In this depiction
35、, all of thehydrogen and carbon atoms are labeled. More commonly, PAHs are shown without labeling the carbon and hydrogenatoms: .PAHs most commonly encountered in the environment contain two to seven fused benzene rings, although PAHs with agreater number of rings are also found. The “ultimate” PAH
36、is graphite, an inert material comprised of planes of fusedbenzene rings. Like all hydrocarbons, PAHs contain only hydrogen and carbon. However, closely related compounds called heterocycles,in which an atom of nitrogen, oxygen, or sulfur replaces one of the carbon atoms in a ring, are commonly foun
37、d with PAHs.CHCCCHCHCHCHHCHCCH2 API PUBLICATION4714Dibenzothiophene, for example, is a sulfur heterocycle. Names and structures of the list of 16 PAHsconsidered “priority pollutants” under the “Clean Water Act” are found in Figure A-1 in the Appendix.PAHs often occur with aliphatic (straight chain)
38、hydrocarbons attached to the rings at one or more points. These compoundsare referred to as “branched” or “alkylated” PAHs. The aliphatic chains are depicted as lines attached to the PAH with theend of the line representing a methyl group (-CH3) and an angle representing an intermediate carbon (-CH2
39、-). Thus,methylnaphthaleneand ethylpyrene are depicted as and .Because there are numerous possible combinations of the location of the alkyl chain on the parent PAH, the number ofchains on the molecule, and the length of the chains, alkylated PAHs are often classified by the number of alkyl carbonst
40、hey contain. Thus, methylnaphthalene, as depicted above, is a C1-naphthalene, while ethylpyrene is a C2-pyrene. 2 Sources of PAHsPAHs are produced in nature through four generalized pathways: 1) low temperature diagenesis of organic matter (part ofthe changes undergone by a sediment after its initia
41、l deposition); 2) the formation of petroleum and coal; 3) incomplete orinefficient combustion at moderate to high temperatures (pyrolysis); and, 4) biosynthesis by plants and animals. Theseprocesses are the primary sourcesof PAHs. Primary sources of PAHs also include anthropogenic (man-made) sources
42、.These include the combustion of fossil fuels and biomass, such as wood, as well as chemical production that results in theformation of PAHs.Because the type distribution of PAHs depends on the temperature of formation, the characteristic distributions of thesedifferent sources can be used to help d
43、istinguish among different sources of PAHs in the environment. Once produced, PAHsare introduced or “delivered” into the environment through a number of pathways (i.e., secondary sources), which aredescribed in Section 3.2.1 PRIMARY SOURCES OF PAHSDiagenic PAHs. DiagenicPAHs are those produced by na
44、tural processes that are set in motion when organic matter isdeposited in naturein soils or sediments. These processes, collectively called diagenesis, begin shortly after deposition ofthe organic matter. These are low temperature processes that occur after oxygen is depleted, and are believed to in
45、volvemicroorganisms, such as bacteria, though non-biological processes may occur in tandem. Relatively few individual PAHsare produced by these early diagenic processes. One of the most notable PAHs produced in this manner is the five-ringedPAH, perylene, shown in Figure 2-1. Perylene is commonly fo
46、und in sediments of rivers, lakes, and oceans at a depth in thesediment where oxygen is reduced. Fossil Fuel (Petroleum and Coal) PAHs. Over geological time and within petroleum reservoirs and coal beds in geologicalstructures, another type of PAHs is producedpetrogenicPAHs. Petrogenic PAHs are form
47、ed at elevated pressures (and athigher temperatures than the formation of diagenic PAHs) within deeply buried layers of sediments. Petrogenic PAHs areformed, for example, when biological organic matter from plankton is converted to petroleum. These processes also canform coal, although the starting
48、biological material (e.g., higher plants and animals) may be different. Petroleum orpetrogenic PAHs and coal-derived PAHs are “fossil fuel” PAHs. The nature of the processes, which convert organic matterFigure 2-1. Perylene, a Five-Ringed Diagenic PAHSA GUIDETOPOLYCYCLICAROMATICHYDROCARBONSFORTHENON
49、-SPECIALIST3to fossil fuels, involves semi-random chemical processes. This fact results in the complexity of many PAH structures thatare found in fossil fuels. Hundreds to thousands of individual PAHs may be produced by nature during the processes thatform petroleum. Nevertheless, while their compositions vary greatly, crude oils have in common the existence of two tosix+ ringed PAHs, with a preponderance of alkylated structures associated with the two to four ringed compounds. The types of PAHs formed as fossil fuels include a complex variety of parent (i.e., unsubstituted),
