Remediation of PAH-Contaminated Soils and Sediments: A ...

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Extraction Table 11. U.S. EPA recommended extraction methods for PAHs (EPA, 2007) Method Matrix Extraction Type Remarks 3510 Aqueous Separatory Funnel Liquid-Liquid Extraction 3520* Aqueous Continuous Liquid- Liquid Extraction 3535 Aqueous Solid-Phase Extraction (SPE) � Inexpensive glassware, fairly rapid. � Labor intensive. � Large volumes of solvent required. � Subject to emulsion problems. � Excellent for samples with particulates (up to 1% solids). � No hands-on manipulation. � More expensive glassware. � Fairly large volumes of solvent. � Lengthy extraction time (6 to 24 hours). � Allow extraction of water containing particulates. � Relatively fast. � Use small volumes of solvent. � Require specialized pieces of equipment. 3540* Solids Soxhlet Extraction � Relatively inexpensive glassware. � No hands-on manipulation. � Efficient extraction. � Lengthy (16 to 24 hours). � Fairly large volumes of solvent. � Rugged extraction method; very few variables can adversely affect extraction efficiency. 3541 Solids Automated Soxhlet Extraction 3545 Solids Pressurized Fluid Extraction (ASE) (Heat & Pressure) � Allows equivalent extraction efficiency in 2 hours. � Requires a rather expensive device. � Rapid and efficient. � Uses small volumes of solvent. � Expensive extraction device. 3550 Solids Ultrasonic Extraction � Fairly rapid (three, 3-minute extractions followed by filtration). � Uses relatively large volumes of solvent. Requires a somewhat expensive device. � much less efficient than the other � Extraction techniques. 3560/1 Solids Supercritical Fluid � Relatively rapid extraction. Extraction (SFE) � Expensive device. *EPA Note: Method 3520 (continuous liquid-liquid extraction of aqueous samples) or Method 3540 (Soxhlet extraction of solid samples), seems to be the most robust ones as these methods have the broadest applicability to environmental matrices. 80
Sample Cleanup After extraction, cleanup methods are used to reduce and or eliminate sample interferences. Most soil and waste extracts require some degree of cleanup, but cleanup for water extracts may be unnecessary. For PAH analysis, the recommended cleanup methods are: � Gel permeation chromatography (3640). This is the most universal cleanup technique for a broad range of semivolatile organics. It is capable of separating high molecular-weight, high boiling material from the sample analytes. It has been used successfully for all the semivolatile base, neutral, and acid compounds associated with the EPA Priority Pollutant and the Superfund Target Compound list to clean up samples prior to GC/MS analysis for semivolatiles and pesticides. � Alumina (EPA 3610 and 3611). Method 3611 may be used for fractionation of aliphatic, aromatic, and polar analytes. � Florisil (EPA 3620) � Silica gel (EPA 3630). The decision process in selecting between the different options available generally depends on the amount of interferences/high boiling material in the sample extract and the degree of cleanup required by the determinative method. For analysis with either the 8100/8310 determinative methods, the cleanup methods 3611, 3630, and 3640 are preferred. Analysis Determination procedures include: � EPA 8100 GC Packed and capillary column with FID (flame ionization detector) � EPA 8310 HPLC Reverse Phase with UV/ Fluorescence detectors. � EPA 8270 GC MS � EPA 8275 Thermal extraction/GC MS � EPA 8410 GC, capillary column FT-IR The Mass Spec procedures are generally more specific, but less sensitive than the appropriate gas chromatographic (GC)/specific detection method. Many GC methods with either selective or non-selective detectors are more appropriate for use where the target analytes are known, are of limited number, and of significantly greater concentration than potential interfering materials. When the site where samples are taken from is not well characterized, and the researchers are concerned about a large numbers of analytes, analysis by GC/MS or HPLC/MS may be more appropriate. 81
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Remediation of PAH-Contaminated Soi
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Abstract Polycyclic aromatic hydroc
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soil is the primary environmental r
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Solubility Solubility of PAH compou
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Figure 1. Structures of US EPA’s
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� If you were to add 2 benzene ri
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and their mutagenic and carcinogeni
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PAH in humans The carcinogenicity o
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persist in the soil (Alexander, 199
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Figure 3. Relative PAH concentratio
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the gas phase was attributed to tem
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increasing rainfall intensity or wi
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in contaminated soils than uncontam
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Ideal biodegradation of PAHs, where
Page 29 and 30: Figure 5. Aerobic degradation of PA
Page 31 and 32: Cometabolism is explained by three
Page 33 and 34: donate electrons. The redox potenti
Page 35 and 36: 1. Fenton’s reagent - formation o
Page 37 and 38: Figure 7. Schematic of integrated e
Page 39 and 40: Figure 8. Possible mechanism for di
Page 41 and 42: Freundlich adsorption equation: x/m
Page 43 and 44: Diffusion: Weber et al. (1992), Web
Page 45 and 46: Biological Techniques for Enhancing
Page 47 and 48: oot extract resulted in continuous
Page 49 and 50: Composting Composting is a form of
Page 51 and 52: The addition of inorganic nutrients
Page 53 and 54: � Yu et al. (2006) found no effec
Page 55 and 56: Carrot Daucus carota Wild and Jones
Page 57 and 58: Surfactants Mass transfer of PAH co
Page 59 and 60: � Straube et al. (2003) showed th
Page 61 and 62: encountered with biodegradation, an
Page 63 and 64: volatilization of some compounds, s
Page 65 and 66: Regulatory Framework Dredged materi
Page 67 and 68: transition phase between slurried s
Page 69 and 70: In addition to equation manipulatio
Page 71 and 72: Coastal Zone Management Act (CZMA)
Page 73 and 74: EPA Region V NA http://www.epa.gov/
Page 75 and 76: Indiana Department of Environmental
Page 77 and 78: New York State Department of Enviro
Page 79: Analytical Methods The following is
Page 83 and 84: Table 13. Detection limits for cert
Page 85 and 86: Citations Accardi-Dey, A., and P.M.
Page 87 and 88: Cerniglia, C.E., and D.T. Gibson. 1
Page 89 and 90: EPA. 2008. Integrated Risk Informat
Page 91 and 92: Harmsen, J. 2007. Measuring bioavai
Page 93 and 94: Kelsey, J.W., B.D. Kottler, and M.
Page 95 and 96: Mackay, D., and D. Callcott. 1998.
Page 97 and 98: O’Mahony, M., A. Dobson, J. Barne
Page 99 and 100: Saison, C., C. Perrin-Ganier, M. Sc
Page 101 and 102: Vessigaud, S., C Perrin-Ganier, L.
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