Native Polycyclic Aromatic Hydrocarbons (PAH) in Coals – a Hardly Recognized Source of Environmental Contamination

Home , Coal in Australia, Kerogen, Retene

SCIENCE OF THE TOTAL ENVIRONMENT 407 (2009) 2461– 2473

available at www.sciencedirect.com

www.elsevier.com/locate/scitotenv

Review Native polycyclic aromatic hydrocarbons (PAH) in coals – A hardly recognized source of environmental contamination

C. Achtena,b, T. Hofmanna,⁎ a University of Vienna, Department of Environmental Geosciences, Althanstr. 14, 1090 Vienna, Austria b University of Münster, Department of Applied Geology, Corrensstr. 24, 48149 Münster, Germany

ARTICLE DATA ABSTRACT

Article history: Numerous environmental polycyclic aromatic hydrocarbon (PAH) sources have been Received 15 October 2008 reported in literature, however, unburnt hard coal/ bituminous coal is considered only Received in revised form rarely. It can carry native PAH concentrations up to hundreds, in some cases, thousands of 29 November 2008 mg/kg. The molecular structures of extractable compounds from hard coals consist mostly Accepted 5 December 2008 of 2–6 polyaromatic condensed rings, linked by ether or methylene bridges carrying methyl Available online 4 February 2009 and phenol side chains. The extractable phase may be released to the aquatic environment, be available to organisms, and thus be an important PAH source. PAH concentrations and Keywords: patterns in coals depend on the original organic matter type, as well as temperature and Native PAH pressure conditions during coalification. The environmental impact of native unburnt coal- Bituminous coal bound PAH in soils and sediments is not well studied, and an exact source apportionment is Hard coal hardly possible. In this paper, we review the current state of the art. Sediment © 2008 Elsevier B.V. All rights reserved. Soil

Contents

1. Introduction ...... 2462 2. Reserves and production ...... 2462 3. Coal diagenesis and associated PAH formation ...... 2463 4. Coal classification ...... 2463 4.1. Coal rank ...... 2464 4.2. Types of fossil organic matter...... 2464 4.3. Coal maceral composition ...... 2464 5. Native PAH concentrations and distribution patterns: Occurrence and correlations with coal rank and type ....2465 6. Native hard coal-bound PAH in soils and sediments ...... 2467 6.1. Unburnt coal particles in soils and sediments ...... 2467 6.2. Identification, patterns and quantification of native PAH from unburnt coal particles in soils and sediments . . 2469 7. Conclusions...... 2470 References ...... 2470

⁎ Corresponding author. E-mail addresses: [email protected] (C. Achten), [email protected] (T. Hofmann).

2005, Chapman et al., 1996). It is well-known that non-native 1. Introduction PAH and other hydrophobic contaminants present in the environment are effectively sorbed to simultaneously present Polycyclic aromatic hydrocarbons (PAH) comprise of many coal particles (sink), which is explained by the strong sorption carcinogenic substances and are ubiquitous in the environ- affinity, high sorption capacity, and slow desorption kinetics ment. The U.S. Environmental Protection Agency regulated 16 compared to other organic matter (Kleineidam et al., 2002; priority pollutant PAH (16 EPA-PAH) spanning from 2–6 Wang et al., 2007; Yang et al., 2008a). However, little is known condensed aromatic rings, which are commonly analyzed. about desorption of native PAH from coal (Yang et al., 2008a,c The occurrence of PAH in soils and sediments is often and references therein). correlated to pyrogenic non-point sources from incomplete Native PAHs in coal are of particular interest in environ- combustion of (fossil) organic matter (Costa and Sauer, 2005; mental research since coal has been mined on a global scale Lima et al., 2005; Müller et al., 1977; Suess, 1976). Point sources for centuries at quantities reaching approx. 5 billion tons in may originate from e. g. oil spills (Short et al., 2007), used 2005 (Thielemann et al., 2007). Unburnt coal particles can be motor oil (Stout et al., 2002b; Napier et al., 2008), or con- released by open pit mining, spills during coal loading, and taminated industrial sites such as manufactured gas plant transport or accidents releasing coal into freshwater or marine sites (coal tar, coke) (Khalil and Ghosh, 2006; Saber et al., 2006; systems (Fig. 1)(French, 1998; Johnson and Bustin, 2006; Pies Stout and Wasielewski, 2004), sites of wood treatment with et al., 2007). On industrial sites, coal is stored in stockpiles for creosote (Murphy and Brown, 2005), aluminum production the production of coke, gas or steam and is subject to erosion. (Booth and Gribben, 2005) or steel works (Almaula, 2005). The Apart from coke and coal tar, manufactured gas plant sites are occurrence of natural or industrially refined petrogenic PAH also known for present unburnt coal particles (Saber et al., has been reported from crude oil/petroleum, naphtha, fuels, 2006; Stout and Wasielewski, 2004). Recently, the addition of diesel, bunker C (marine) fuels and lubricating oil (Boehm carbon particles like activated carbon and coke to reduce et al., 1998, 2001; Short et al., 2007; Stout et al., 2002b; Wang availability of organic contaminants has been discussed and and Fingas, 2006). Biogenic PAH such as retene (Simoneit et al., investigated (Zimmerman et al., 2004; Werner et al., 2006; 1986), triaromatic triterpenoids/steroids (Tissot and Welte, Brändli et al., 2008; Sun and Ghosh, 2008). Some of these 1978) or partially perylene (Meyers and Ishiwatari, 1993) have materials may also contain PAH (e.g. coke) and add up to the been identified. total concentration present in sediments. In some areas, coal Surprisingly, unburnt coal has rarely been considered as a naturally eroded into aquatic systems from sedimentary rock PAH source in soils and sediments (Ahrens and Morrisey, outcroppings containing coal seams (Stout et al., 2002a). 2005). In addition to sorbed PAH once being exposed to the Finally, native and sorbed coal bound PAH may be relocated environment, original hard coals from the seam can contain by colloidal/particulate transport of the coal particles them- PAH up to hundreds and, in exceptional cases, thousands of selves enhancing (or reducing) the mobility of hydrophobic mg/kg (Stout and Emsbo-Mattingly, 2008; Willsch and Radke, organic contaminants (Hofmann 2002, Hofmann et al., 2003a, 1995). This neglect was expressed by Walker et al. (2005), who b; Hofmann and von der Kammer, 2008). described coal as an unknown or unsuspected source of PAH. In this paper we focus on coal being a possible PAH source. In coals of low rank, such as lignite, sub-bituminous coal or The aim of this paper is to review the state of the art brown coal, significantly lower PAH concentrations were addressing the (1) characterization of PAH predominantly in detected (e. g. 13 mg/kg EPA-PAH, Püttmann, 1988). Up to hard coals/ bituminous coals, (2) the formation of PAH and 30 mg/kg alkylnaphthalenes, but no EPA-PAH were observed influencing factors such as hard coal maturity and origin by Bechtel et al. (2005). Their occurrence in brown coals is together with (3) the occurrence of hard coals and coal bound explained by degradation of pentacyclic angiosperm-derived PAH in soils and sediments. triterpenoids (Püttmann and Villar, 1987; Tuo and Philp, 2005). In a sub-bituminous coal from the Wealden Basin at Zwische- nahn, Germany, 243 mg/kg of total PAH and 14 mg/kg of EPA- 2. Reserves and production PAH were detected (Radke et al., 1990). Kashimura et al. (2004) identified semi-quantitatively naphthalene, phenanthrene, Currently, the top eleven hard coal producing countries or anthracene, pyrene, chrysene, benzo[a]anthracene, perylene, countries with more than 10 billion tons of hard coal reserves benzo[a]pyrene, benzo[e]pyrene, benzo[b]chrysene, dibenzo[a, are China, U.S.A., India, Australia, South Africa, Russia, i]pyrene, dibenzo[a,h]pyrene, and coronene in Victorian brown Indonesia, Poland, Kazakhstan, Ukraine and Germany coals from Australia. Other studies presented qualitative (World Coal Institute, 2007). Worldwide hard coal production results only (Chaffee and Johns, 1982; Stout et al., 2002a). has increased from less than 1 to 4.96 billon tons from 1900 to Besides other environmental concerns regarding coal use 2005 (Thielemann et al., 2007). The significance of coal as an and production, in theory their native PAH content could pose energy source has recently been predicted to increase in the a risk to soils and sediments, however until today, no study future (Massachusetts Institute of Technology, 2007). In 2004, clearly showed it. Whereas physical effects of coal dust on China, the U.S.A. and India produced about 2, 1 and 0.4 billion organisms have often been investigated (e. g. Ahrens and tons of hard coal and held about 60, 100 and more than 80 Morrisey, 2005 and references therein), less is known about billion tons of reserves, respectively. Australia, South Africa chemical effects due to coal constituents such as PAH. The and Russia have reserves of about 40–50 billion tons of hard ecotoxicological impact of coal particles in soils and sedi- coal each and annual productions of less than 0.3 billion tons ments has not yet been studied in detail (Ahrens and Morrisey, each. With a share of more than 70%, Australia is the largest SCIENCE OF THE TOTAL ENVIRONMENT 407 (2009) 2461– 2473 2463

Fig. 1 – Coal emission sources to the aquatic environment (modified after Ahrens and Morrisey, 2005).

export country compared to 8%, 3% and no significant methyl, and less of ethyl, propyl or butyl functional groups. amounts of exports from the U.S.A., China and India, The average number of aromatic rings per structural unit in respectively (Max-Planck-Institut für Plasmaphysik, 2000; mostcoalsis3–5(Stout et al., 2002b) with some individual 2001a,b; 2002a,b). Due to the economic combination of large units containing up to 10 rings. A typical hard coal is open pit mining near the East Coast and railway connections characterized by 2–6PAHlinkedbymethylenebridgeswith to several coal harbors, Australia is able to export 70% of the additionally bound aliphatic side chains and phenol func- coal to Japan and other Asian countries and about 15% to tional groups. With increasing rank, aromatic units increase Europe. Since the 1980s, the export of coal in Australia has from 3–4 condensed rings at low rank to about 30 fused rings doubled. In 1991, Russia was the largest hard coal exporting in anthracite. Concurrently, the lengths of side chains country worldwide, however since the break-up of the Soviet decrease. Union, the production and export numbers have reduced In addition to the network structure, a multitude of small significantly. molecules, i.e. a ‘mobile phase’, is present within the network (Given, 1987) and is of particular environmental interest. These molecules can be released from the coal network more 3. Coal diagenesis and associated PAH rapidly because they are less bound to the macromolecular formation matrix compared to the cross-linked molecules within the network. The type and rank of a coal influences the When remains of land plants, particularly peat, are buried, it concentration and composition of the mobile phase, which is converted to coal by prolonged exposure to elevated is abundantly present in coals ranking within the oil genera- temperatures and pressures in the subsurface. The concur- tion window. The mobile phase is eliminated during hot rent physico-chemical changes are complex (Taylor et al., steam treatment used for active carbon production from e. g. 1998). Generally, resistant plant biopolymers, e. g. lignin, are hard coal or charred coconut shells. During coal heating at converted into highly aromatic, three-dimensional, network manufactured gas plant sites, the linkages between some of matrix in the order of increasing maturity: peat → lignite → the carbon units are cleaved, thereby releasing the conjugated sub-bituminous coal → bituminous coal → anthracite → aromatic rings into the mobile fraction (gas and coal tar). graphite (Fig. 2). The proportion of conjugated aromatic rings per structural unit within the matrix determines the aromaticity and increases with increasing coalification, ultimately 4. Coal classification resulting in graphite. Dehydroxylation, demethylation and condensation reactions produce a relative increase in carbon Coal is being classified according to its various physico- combined with a decrease in oxygen and hydrogen as it is chemical properties (van Krevelen, 1993). Due to the expected suggested in the van-Krevelen-diagram (Fig. 3, van Krevelen, impact on the formation of PAH, we consider those classifica- 1993). Aromatic structures are commonly linked by ether or tion systems, which are based on rank, types of fossil methylene bridges. Aliphatic side chains consist mainly of sedimentary organic matter and coal maceral composition. 2464 SCIENCE OF THE TOTAL ENVIRONMENT 407 (2009) 2461– 2473

on different stabilities of the alkyl functional groups at different positions on the molecules. The β-positions are more thermo- dynamically stable (e. g. 2- and 3-methylphenanthrenes) compared to the α-positions (e. g. 1- and 9-methylphenanthrenes) and their formation is preferred with increasing rank (Willsch and Radke, 1995). Trimethylnaphthalene ratios (TNR-1, TNR-2), methylphenanthrene ratio (MPR) (Radke and Welte, 1981), dimethylphenanthrene ratios (DPR-1, DPR-2), methylphenanthrene indices (MPI-1 and MPI-4) (Radke et al., 1982b; Radke et al., 1984; Willsch and Radke, 1995) and dimethylnaphthalene ratios (DNR-1 to -5) (Alexander et al., 1983, 1985) were described.

4.2. Types of fossil organic matter

Kerogen represents about 90% of the fossil organic carbon in sediments (van Krevelen, 1993). Three types can be recognized (Tissot and Welte, 1978); Type I is primarily derived from algal lipids (hydrogen-rich) and is mainly of aliphatic nature; Type II is primarily formed of marine plankton and bacteria (both exhibit a high gas and oil generating potential); Type III, the most common type of coal (humic coals, oxygen-rich) contains organic matter derived from terrestrial higher plants and exhibits a mostly aromatic nature. Its potential for oil generation is low. After successive alteration stages of diagenesis, catagenesis and metagenesis, finally, a chemically uniform product (graphite) is generated (Fig. 2).

4.3. Coal maceral composition

A classification system based on the fossilized plant remains (macerals) observed under the microscope is commonly used in coal research (Teichmüller, 1989). Three different maceral groups can be distinguished: (1) vitrinite, which may be considered the standard coalification product of woody tissue,

Fig. 2 – Small molecule sections of lignin (top), bituminous coal (middle) and anthracite (bottom) (modified after the College of Liberal Arts and Sciences, Western Oregon University, and after U.S., Lignin Institute, U.S.A.)

4.1. Coal rank

Volatile matter content, vitrinite reflectance (% Ro), carbon and water content, calorific value, hydrocarbon indices, temperature of maximum hydrocarbon formation during heating (Tmax)andotherfactors(Tissot and Welte, 1978)are used to measure coal rank. Vitrinite reflectance is commonly used due to its stability over a wide range of coal rank, its abundance and independency on kerogen types or bitumen content (Stach et al., 1982).Itisameasureofthepercentageof light reflected from the vitrinite macerals at high magnifica- tion (×500) in oil immersion. Lignite is characterized by approx. 0.3% Ro, the transition zone from brown coal to hard coal is at approx. 0.65% Ro andfromhardcoaltoanthracite – approx. 2.2 2.5% Ro (Fig. 4). The oil generation window ranges – from 0.5 1.3% Ro. Various indices of parent and alkylated naphthalenes Fig. 3 – van Krevelen diagram (modified after van Krevelen, or phenanthrenes can also be applied. They are based 1993). SCIENCE OF THE TOTAL ENVIRONMENT 407 (2009) 2461– 2473 2465

Fig. 4 – Total polycyclic aromatic hydrocarbon concentrations against coal rank of different coals. Dashed line: total aromatic hydrocarbons (Radke et al., 1990), solid line: total PAH∑43 (Stout and Emsbo-Mattingly, 2008), dash-dotted line: EPA-PAH concentrations (Stout and Emsbo-Mattingly, 2008), dotted line: EPA-PAH concentrations (Zhao et al., 2000); (and data compiled from Chen et al., 2004; Pies et al., 2007; 2008a,b; Radke et al., 1990; Willsch and Radke, 1995; Van Kooten et al., 2002).

(2) liptinite, which has a higher hydrogen-content compared rank vary and at the same coal rank it decreases in the order to vitrinite, and (3) inertinite, which shows a lower hydrogen- inertiniteNvitriniteNliptinite. content compared to vitrinite. The maceral groups of vitrinite and liptinite form the reactive components in the carbonization and liquefaction processes of coal, whereas inertinite 5. Native PAH concentrations and distribution behaves as an inert additive (van Krevelen, 1993). patterns: Occurrence and correlations with coal Macerals originating from woody and cortical tissues rank and type include the following (numbers in brackets refer to maceral The presence of PAH in hard coals has been reported from groups): several countries, e. g. Germany (76 samples) (Püttmann and Schaefer, 1990; Radke et al., 1982a, 1990; Radke and Welte, 1981; • Vitrinite (with wooden structure: telinite, 1, without struc- Willsch and Radke, 1995), Canada (34 samples) (Radke et al., ture: collinite, 1), 1982b; Willsch and Radke, 1995), U.S.A. (48 samples, including • Fusinite (charred cell walls, characteristic maceral of fossil Alaska) (Hayatsu et al., 1978; Kruge, 2000; Kruge and Bensley, char coal, 3). 1994; Stout et al., 2002a; Van Kooten et al., 2002; White and Lee, Macerals with a clear origin of plant material and other 1980; Zhao et al., 2000; Stout and Emsbo-Mattingly, 2008), Japan woody tissues include: (3 samples) (Radke et al., 1990), France (1 sample) (Kruge, 2000), China (5 samples) (Chen et al., 2004; Tang et al., 1991) and Brazil • Sporinite (fossil remains of spore exines, 2), (1 sample) (Püttmann, 1988). However, many studies present • Cutinite (constituent formed from cuticules, 2), qualitative results only. A summary of the limited published • Resinite (fossil remains of plant resins, 2), quantitative PAH data available (Table 1) shows that concen- • Alginate (remains of algae bodies, 2) and trations vary widely, from 1 to about 2500 mg/kg. PAH in a • Sclerotinite (fossil remains of fungal sclerotia, 3). sample set of several hard coals from international large coal basins are currently studied (Micic et al., 2007). The properties of different coals are strongly affected by Detected compounds include 16 EPA-PAH, benzo[e]pyrene, the types and proportions of the various macerals present perylene, coronene, and their alkylated derivatives (Püttmann, therein. The aromaticity of coal macerals in coals of different 1988; Van Kooten et al., 2002; Willsch and Radke, 1995), as well 2466 SCIENCE OF THE TOTAL ENVIRONMENT 407 (2009) 2461– 2473

Table 1 – Summary of total and 16 EPA polycyclic aromatic hydrocarbon concentrations in coals Total PAHs EPA-PAHs References [mg/kg] [mg/kg]

High volatile bituminous coal A, Elmsworth gasfield, 10-11-71-11W6, Canada 2429.1 152.1 High volatile bituminous coal A, Elmsworth gasfield, 10-03-70-10W6, Canada 2412.3 136.6 Medium volatile bituminous coal, Ruhr basin, Osterfeld, Germany 1037.2 153.3 Medium volatile bituminous coal, Ruhr basin, Hugo, Germany 933.8 123.6 Low volatile bituminous coal, Ruhr basin, Westerholt, Germany 1200.7 163.9 Low volatile bituminous coal, Ruhr basin, Blumenthal, Germany 786.5 155.4 Willsch and Radke (1995) Low volatile bituminous coal, Elmsworth gasfield, 06-19-68-13W6, Canada 546.4 98.6 Low volatile bituminous coal, Ruhr basin, Haard, Germany 567.7 154.8 High volatile bituminous coal, Wealden Basin, Nesselberg, Germany 656.2 43.1 High volatile bituminous coal, Wealden Basin, Barsinghausen, Germany 554.4 56.7 Radke et al. (1990) High volatile bituminous coal, Saar, Ensdorf, Germany 165.9 50.5 Medium volatile bituminous coal, Germany 68.0 22.4 Pies et al. (2007) Bituminous coal, Germany 127.6 28.7 Lignite A, Northern Great Plains, Beulah, USA 8.5 a 1.2 Lignite A, Northern Great Plains, Pust, USA 6.5 a 1.0 Sub-bituminous coal C, Northern Great Plains, Smith-Roland, USA 12.0 a 0.1 Sub-bituminous coal C, Gulf Coast, Bottom, USA 14.0 a 1.6 Sub-bituminous coal B, Northern Great Plaines, Dietz, USA 14.0 a 0.8 Sub-bituminous coal B, Northern Great Plaines, Wyodak, USA 5.4 a 0.3 Sub-bituminous coal A, Rocky Mountains, Deadman, USA 12.0 a 1.5 High volatile bituminous coal C, Rocky Mountains, Blue, USA 77.0 a 5.3 High volatile bituminous coal B, Eastern Coal, Ohio #4A, USA 60.0 a 8.2 High volatile bituminous coal A, Rocky Mountains, Blind Canyon, USA 78.0 a 4.4 High volatile bituminous coal A, Eastern Coal, Pittsburgh, USA 76.0 a 11.0 Stout and Emsbo-Mattingly (2008) Medium volatile bituminous coal, Rocky Mountains, Coal Basin M, USA 29.0 a 1.8 Low volatile bituminous coal, Eastern Coal, Pocahontas #3, USA 20.0 a 3.8 Semianthracite, Eastern Coal, PA Semi-Anth. C, USA 5.9 a 2.1 Anthracite, Eastern Coal, Lykens Valley #2, USA 0.2 a b0.1 High volatile bituminous coal, Blind Canyon, USA 78.3 – Stout et al. (2002b) High volatile bituminous coal C-1, USA 7.5 0.5 High volatile bituminous coal C-2, USA 3.4 0.4 High volatile bituminous coal C-3, USA 2.4 0.3 High volatile bituminous coal B-1, USA 1.6 0.3 High volatile bituminous coal B-2, USA 12.7 2.4 High volatile bituminous coal A-1, USA 13.7 5.4 Zhao et al. (2000) High volatile bituminous coal A-2, USA 27.6 6.4 Low volatile bituminous coal, USA 1.2 0.3 Anthracite, China 2.5 1.8 Chen et al. (2004) Bituminous coal, Brazil 13.0 – Püttmann (1988)

a Sum of 43 PAHS.

as retene, methylated chrysenes, methylated picenes, tetra- respectively. Both measurements lie within the oil generation hydrochrysenes, hydropicenes and methylphenanthrenes in window. Stout et al. (2002b) and Stout and Emsbo-Mattingly coals ranging from lignite to anthracite (Barrick et al., 1984). (2008) observed maximum PAH concentrations in coals of about – Recently, 15 coal samples of different rank from the U.S.A. 0.5 0.9% Ro. Raises of PAH concentrations up to 1.1% Ro is were analyzed for PAH concentrations and source character- explained by increasing condensation, carbon concentration ization of coal (Stout and Emsbo-Mattingly, 2008). Low and aromatization of coal with increasing maturity (Suggate – N concentrations of 16 EPA-PAH from 0.035 11 mg/kg were and Dickinson, 2004). However, at high rank ( 1.1% Ro)an observed with a mean of 3 mg/kg. Concentrations ranging increase of the polyaromatic compounds with more than 6 from 0.18–78 mg/kg with a mean of 30 mg/kg were reported condensed rings may occur, at least partially, at the expense of for 43 PAH compounds. Highest concentrations occurred in 2–6 ring PAH due to rearrangement and fragmentation reac- high volatile bituminous coals. tions. This process may be responsible for decreased total PAH Considering the chemical processes during coalification, a (2–6 ring) concentrations in e. g. anthracite (Chen et al., 2004). systematic relationship between PAH concentrations and coal Not only PAH concentrations but also PAH patterns change maturity is expected. In Fig. 4, total PAH concentrations from the with increasing rank. Sub-bituminous coals contain PAH, literature are plotted against corresponding coal rank and no predominantly in the form of chrysene, picene and their correlation can be deduced. However, if coals of similar origin alkylated derivatives. During coalification, PAH patterns are considered, the maximum total aromatic hydrocarbon yield change because primary products of higher thermodynamic (Radke et al., 1990) and maximum EPA-PAH concentrations stability are generated at the expense of less stable com-

(Zhao et al., 2000) were observed at 0.9% Ro and 1.1% Ro, pounds. At the boundary between sub-bituminous/high SCIENCE OF THE TOTAL ENVIRONMENT 407 (2009) 2461– 2473 2467 volatile bituminous coal (or brown/hard coal), distinct low ans and dimethylphenanthrenes as an indicator for organic molecular weight aromatic compounds are generated. Bi- and matter type I, II or III. tricyclic PAH are formed mainly in the high volatile bituminous coal stage and provide a pattern of compounds showing a structural relationship to natural precursor molecules, e. g. 6. Native hard coal-bound PAH in soils and phenanthrene derivatives, which are thought to be derived sediments from plant resins and steroids (Püttmann and Schaefer, 1990). With increasing maturity, a shift occurs in the PAH pattern 6.1. Unburnt coal particles in soils and sediments from high concentrations of naphthalene and its alkylated derivatives at low hard coal rank to a relative increase of 4–6- The presence of unburnt coal particles has been reported from ring PAH at high rank (Ahrens and Morrisey, 2005). Simulta- marine and freshwater sediments, as well as soils. In the marine neously, the oxygen content is lowered, which results in lower environment, the Exxon Valdez oil spill in Alaska, U.S.A., concentrations of hydroxylated aromatic compounds, such as triggereddetaileddiscussionwhetherPAHinsedimentsof phenols, which are most prevalent in lignite. Due to rearran- Prince William Sound originated from the spill or from naturally gement and fragmentation reactions at increasing rank, outcropping coal seams near the shore (Boehm et al., 2001; Short aromatic hydrocarbons are no longer directly derived from et al., 1999). In coastal sediments, coal particles in some cases biological precursors. Similar distribution patterns compared reached sizes of some tens of centimeters in diameter, e. g. at to those of other coals of comparable rank occur and the Katalla beach. Earlier, Tripp et al. (1981) concluded that unburnt individual PAH patterns of coals become less complex coal can be a significant source of sediment hydrocarbons in the (Püttmann and Schaefer, 1990). coastal marine environment. Barrick et al. (1984) correlated The changes in PAH patterns with increasing rank are shown hydrocarbons from 16 Western Washington coals to sediment b – in Fig. 5. At low hard coal rank (Ro 1%, Fig. 5a), C0 C4 samples from Puget Sound and Lake Washington. alkylnaphthalenes (up to about 30%) are the dominant PAH Estuaries in the vicinity of mining activity can be impacted – group. C0 C3 alkylphenanthrenes rank second and typically by coal emissions as reported from the Severn Estuary, Great comprise b10% of total PAH. Retene is present up to about 25%, Britain, where coal mining dates back to the mid-16th century whereas C1 +C2 alkylfluorenes and methylfluoranthenes are only (French, 1998). Intertidal mudflat sediments are estimated to detected at low concentrations (up to about 2% each). Other PAH, hold around 105–106 tonnes of coal. Coal emissions into if present, only occur at trace concentrations. With increasing sediments were reported from harbors such as Hamilton – – rank (Ro =1.26 1.65%, Fig. 5b), the C0 C3 alkylnaphthalenes Harbour (Curran et al., 2000) and Roberts Bank coal terminal, dominance is diminished, and C4 alkylnaphthalenes and retene both in Canada (Johnson and Bustin, 2006). Coal particles are no longer detected. In contrast, the phenanthrene dominance present in sediments made up 10.5 to 11.9% dry weight of the often increases with concentrations N10% of the total PAH soil mass in the vicinity of coal-loading terminals and was present. C1 +C2 alkylfluorene and methylfluoranthene concen- reported as non-hydrolysable solids. An increase of the coal trations increase, often reaching about 5% of the total aromatic concentration in the uppermost 2–3 cm within about 3 km2 hydrocarbons. Generally, higher molecular weight PAH concen- was observed from 1.8% to 3.6% during the time from 1977 to trations are increased compared to those observed at lower hard 1999 (Johnson and Bustin, 2006). coal rank, and C0 +C1 alkylchrysenes and isomers are present up In freshwater sediments and floodplain soils, unburnt coal to about 4%. Significant increases in higher molecular weight particles were identified at the Lippe (Klos and Schoch, 1993), N PAH occur at high rank such as anthracite (Ro 2.5%, Fig. 5c). Here, Saar and Mosel rivers, Germany, due to former coal mining naphthalenes are not present and the dominance of parent PAH (Hofmann et al., 2007; Pies et al., 2007, 2008a; Yang et al., 2007). and methylphenanthrenes is observed in the single reported Hard coal particle concentrations of the heavily coal-impacted sample. Higher molecular weight PAH such as benzo[e]pyrene floodplain soil samples were in the range of 45–74 vol.% of the and benzo[b]fluoranthene are detected at N10% each and light fraction (the fraction with a density b2 g/cm3, predomi- coronene at N2%. The degree of alkylation of aromatic hydro- nantly organic carbon). PAH concentrations of the light carbons decreases with increasing coal rank from low volatile fractions in the samples ranged from 370–460 mg/kg (sum of bituminous coal to anthracite. In summary, a shift from alkylated EPA-PAH, 1- and 2- methylnaphthalenes) dry weight and bi- and tricyclic PAH at lower hard coal rank to higher molecular thereby contributed 89.9% to the total (sum of EPA-PAH, 1- and parent compounds in anthracite has been observed, which is in 2- methylnaphthalenes) sediment PAH content (Yang et al., accordance with increasing carbon concentration and aromati- 2008b). zation during the coalification process. Apparently, PAH patterns In soils, unburnt coal particles and elevated hydrocarbon shift with increasing rank from a “bell-type" shape (C0-C4 concentrations were identified in dust and soil samples from naphthalenes and phenanthrenes) to a “slope-type" shape the Ojców National Park, Poland (Schejbal-Chwastek and which is commonly known to be typical of a pyrogenic PAH Marszalek, 1999). During the coal combustion process, fly origin. ash notably still contains unburnt coal particles at low Correlations between PAH distributions and the original concentrations (Külaots et al., 2004; Lopez-Anton et al., 2007). organic matter type of coals are expected, since different coal These are not commonly investigated in soils and sediments. macerals can produce different mixtures of aromatic com- It cannot be excluded that native PAH from co-emitted pounds. For example, liptinites are known as sources for unburnt coal particles contribute to health issues resulting naphthalenes or vitrinite for biphenyls (Tang et al., 1991). Kruge from coal combustion linked emissions (Liu et al., 2008; (2000) observed correlations between dibenzothiophenes/-fur- Tremblay, 2007). For example, in China, since 2001 an increase 2468 SCIENCE OF THE TOTAL ENVIRONMENT 407 (2009) 2461– 2473

– b – Fig. 5 Total polycyclic aromatic hydrocarbon patterns at different coal ranks: a) 1% vitrinite reflectance (Ro), b) 1.26 1.65% Ro, N and, c) 1.7% Ro; Naph: naphthalene, Acy: acenaphthylene, Ace: acenaphthene, Fl: fluorene, Phe: phenanthrene, Ant: anthracene, Flu: fluoranthene, Pyr: pyrene, BaA: benzo[a]anthracene, Chry+Tri: chrysene and triphenylene, BbF: benzo[b] fluoranthene, BkF: benzo[k]fluoranthene, Bep: benzo[e]pyrene, Bap: benzo[a]pyrene, Incdp: indeno[1,2,3-cd]pyrene, BghiP: – – benzo[g,h,i]perylene, Ret: retene, Cor: coronene, C0: parent compound, C1 C4: C1 C4 alkylated derivatives. SCIENCE OF THE TOTAL ENVIRONMENT 407 (2009) 2461– 2473 2469

Fig. 5 (continued).

of 40% in birth defects was reported in regions of intensive coal Yang et al., 2008b). However, since the method is complex and mining and burning, i.e. in Shanxi Province. However, no time-consuming it is seldom resorted to. In the coal mining statistical significance was detected between malformations area of Ruhr-Lippe, Klös and Schoch (1993) could correlate during early embryogenesis and distance from coal plants (Gu different historical periods of low coal-production due to an et al., 2007). economic crisis to reduced PAH concentrations found in age- Several investigations on emitted unburnt coal particles dated sediments. However, it was not investigated whether from opencast mining have been reported from India: Jharia the PAH emissions originated from coal combustion or coalfield (Ghose and Majee, 2000a,b), Raniganj coalfield (Singh unburnt coal particles. and Sharma, 1992), Manuguru coal belt area of Andhra Frequently, hydrocarbon fingerprints and indices are used Pradesh (Sekhar and Rao, 1997) and Lakhanpur area of Ib to distinguish between petrogenic and pyrogenic PAH in soils Valley coalfield (Chaulya, 2004). In the Block II opencast and sediments (Budzinski et al., 1997; Stout et al., 2002b; Wang, project at the Jharia coalfield, different emission sources 2007; Pies et al., 2008b), but it is difficult to identify PAH derived were quantified. Based on the project holding coal reserves from coal vs. PAH from oil. These uncertainties are assumed to of 37 Mt occupying 674 ha of land, an estimated total amount be predominantly responsible for the lack of information on of 9368 kg/day of coal dust is emitted mainly due to mining native coal-bound PAH in soils and sediments. This gap of activities and wind erosion of the exposed area (Ghose, 2007). knowledge can easily confound forensic attempts of source The predominant emission sources were the crushing and identification (Stout et al., 2002b), as evident in the case of the feeding point for size reduction (40%), the unloading point of Exxon Valdez oil spill (Boehm et al., 1998, 2001; Short et al., 1999; the conveyor belt (31%), wind erosion of the total area (17%), Van Kooten et al., 2002). In the investigated sediments, Barrick transportation on haul road (5.2%), loading into dumper (3%) et al. (1984) and Stout et al. (2002a,b) observed dominating and onto the conveyor belt (2%). Also, in the Manuguru coal alkylated naphthalenes with a “bell-shaped” pattern typical for belt area of Andhra Pradesh, an increase in coal emissions in petrogenic sources. Regarding the aliphatic fraction, n-alkanes recent years was observed (Sekhar and Rao, 1997). exhibited a characteristic odd-even predominance within the C25-C31 range in a high volatile bituminous coal (Stout et al., 6.2. Identification, patterns and quantification of native 2002b). Low ratios of triaromatic steranes to methylchrysenes PAH from unburnt coal particles in soils and sediments in coal (b0.2) compared to high ratios (11 and 13) were detected in oil (Short et al., 1999). Unburnt coal particles in soils and sediments can be identified Barrick and Prahl (1987) described alkylphenanthrenes, by coal petrography (Ligouis et al., 2005; Taylor et al., 1998; alkylchrysenes and alkylpicenes concentrated in coal 2470 SCIENCE OF THE TOTAL ENVIRONMENT 407 (2009) 2461– 2473 fragments of sediments near river mouths in the central and phase is of special environmental interest because it is southern Puget Sound region, U.S.A., originating from river more mobile and is expected to have higher bioavailability. systems draining coal-bearing strata. Surely, the most obvious Aromatization of coals increases with increasing rank from characteristics of native PAH from coals are the predominance sub-bituminous coal to anthracite. In coals, oil (mobile phase, of naphthalene, phenanthrene and their alkylated derivatives, including 2–6 ring PAH) is generated at low to medium hard – however, these are also typical of PAH from other petrogenic coal rank from 0.5 1.3% Ro. In this range also maximum PAH sources such as oil. Soil from a manufactured gas plant site concentrations may occur but they also depend on origin (e. g. contained a dominance of naphthalene, phenanthrene, chry- maceral composition). Naphthalene, phenanthrene, chrysene sene and their alkylated derivatives in a coal sample separated and alkylated derivatives are characteristic petrogenic PAH. To from the soil, but not in other samples containing tar or date, it is hardly possible to distinguish PAH derived from oil residual petroleum (Stout and Wasielewski, 2004). EPA-PAH vs. PAH from coal. If other geosorbents such as black carbon concentrations of the coal sample were around 10 mg/kg. are not present at higher levels, limited evaporation of Increased concentrations of fluoranthene, phenanthrene, naphthalenes compared to the greater losses in other samples pyrene and chrysene were reported from a coal pile runoff in may be a helpful indicator of the presence of coal. Other Hamilton Harbour, Canada (Curran et al., 2000). techniques, like organic petrography, are of major importance The PAH patterns of the coals investigated in the aftermath for source identification. The data is presently insufficient for of the Exxon Valdez oil spill were also dominated by naphtha- us to ascertain if native PAH derived from unburnt hard coal lene, phenanthrene and alkylated derivatives (Short et al., particles pose a severe risk for humans or organisms of the 1999; Boehm et al., 2001). EPA-PAH concentrations are benthos and soil. In addition, coal particles might also be estimated at approx. 500 mg/kg in coals from the Kulthieth relocated by wind erosion, transport/loading, or accidental Formation (Van Kooten et al., 2002). In these coals, the releases (Ghoose and Majee, 2000a,b). Coal particles in the presence of naphthalene, C1 and C2 naphthalenes tended to environment may sorb hydrophobic organic contaminants be greater than in seep oils, whereas the higher molecular and enhance their relocation by colloidal/particulate transport weight PAH were more abundant in seep oils. Low molecular (Hofmann et al., 2003a; Hofmann and Wendelborn, 2007; weight PAH can easily volatilize during sample preparation, Hofmann and von der Kammer, 2008). For most of the large e. g. if the extract is dried, which was not the case in this study. coal basins, these topics are not well studied. They should be Naphthalenes volatilize more easily from oil or tar compared included into an assessment of the environmental impacts of to coal since coal is a very strong sorbent. Therefore, the coal. decrease in naphthalene concentrations in soils and sediments, after being subject to gentle evaporation, could be regarded as an indicator for oil-bound PAH but not coal-bound REFERENCES PAH. At the Mosel River, Germany, naphthalenes were also shown to be the key compounds for source apportionment of PAH. Native PAH in Saar coals (70–165 mg/kg EPA-PAH) are the Ahrens MJ, Morrisey DJ. Biological effects of unburnt coal in the – major reason for elevated PAH concentrations in Saar and marine environment. Oceanogr Mar Biol Ann Rev 2005;43:69–122. Mosel River floodplain soils downstream from mining activity Alexander R, Kagi RI, Sheppard PN. Relative abundance of (Hofmann et al., 2007; Pies et al., 2007, 2008a; Yang et al., 2007, dimethylnaphthalene isomers in crude oils. Chromatorgraphy 2008b,). Although major mining activity occurred between 200 1983;267:367–72. to 50 years ago, naphthalenes and alkylated derivatives still Alexander R, Kagi RI, Roland SJ, Sheppard PN, Chirila TV. The dominate the PAH patterns in the floodplain soils (Pies et al., effects of thermal maturity on distributions of 2008a,b). Recently, Stout and Emsbo-Mattingly (2008) showed dimethylnaphthalenes and trimethylnapthalenes in some that PAH distributions and indices varied with coal rank and ancient sediments and petroleums. Geochim Cosmochim Acta 1985;49:385–95. concluded that particulate coal in soils and sediments cannot Almaula S. Polycyclic aromatic hydrocarbons from steelmaking. be universally represented by a single set of diagnostic Environ Forensics 2005;6:143–50. parameters based on the investigated samples. Barrick RC, Prahl FG. Hydrocarbon geochemistry of the Puget Sound region – III. Polycyclic aromatic hydrocarbons in sediments. Estuar Coast Shelf Sci 1987;25:175–91. 7. Conclusions Barrick RC, Furlong ET, Carpenter R. Hydrocarbon and azaarene markers of coal transport to aquatic sediments. Environ Sci Technol 1984;18:846–54. Coal-bound native PAH in soils and sediments have been Bechtel A, Sachsenhofer RF, Zdravkov A, Kostova I, Gratzer R. studied to a minor extent, despite 30 years of research on PAH Influence of floral assemblage, facies and diagenesis on in the environment. Their impact on the environment is not petrography and organic geochemistry of the Eocene Bourgas well understood. Unburnt hard / bituminous coal emissions coal and the Miocene Maritza-East lignite (Bulgaria). Org from mining activity particularly impact those countries hold- Geochem 2005;36:1498–522. ing large coal basins. Coal particles were found in concentra- Boehm PD, Page DS, Gifillan ES, Bence AE, Burns WA, Mankiewicz PJ. Study of the fates and effects of the Exxon Valdez oil spill on tions up to approx. 75 vol. % of the light fraction (b2g/cm3)of benthic sediments in two bays in Prince William Sound, soils and sediments and they contain PAH concentrations Alaska. 1. Study design, chemistry, and source fingerprinting. ranges from trace level up to thousands of mg/kg. Environ Sci Technol 1998;32:567–76. Hard coal consists of a macromolecular network phase and Boehm PD, Page DS, Burns WA, Benze AE, Makiewicz PJ, Brown JS. a mobile phase, and PAH are part of both. However, the latter Resolving the origin of the petrogenic hydrocarbon background SCIENCE OF THE TOTAL ENVIRONMENT 407 (2009) 2461– 2473 2471

in Prince William Sound, Alaska. Environ Sci Technol hydrophobic organic contaminants in porous media. Environ 2001;35:471–9. Pollut 2008, doi:10.1016/j.envpol.2008.10.022. Booth R, Gribben K. A review of formation, environmental fate, Johnson R, Bustin RM. Coal dust dispersal around a marine coal and forensic methods for PAHs from aluminum smelting terminal (1977–1999), British Columbia: the fate of coal dust in processes. Environ Forensics 2005;6:133–42. the marine environment. Int J Coal Geol 2006;68:57–69. Brändli RC, Hartnik T, Henriksen T, Cornelissen G. Sorption of Kashimura N, Hayashi J, Li C, Sathe C, Chiba T. Evidence of native polyaromatic hydrocarbons (PAH) to black carbon and poly-condensed aromatic rings in a Victorian brown coal. Fuels amended activated carbon in soil. Chemosphere 2004;83:97–107. 2008;73:1805–10. Khalil MF, Ghosh U. Role of weathered coal tar pitch in the Budzinski H, Baumard P, Papineau A, Wise S, Garrigues P. partitioning of polycyclic aromatic hydrocarbons in Focused microwave assisted extraction of polycyclic manufactured gas plant site sediments. Environ Sci Technol aromatic compounds from standard reference materials, 2006;40:5681–7. sediments and biological tissues. Polycyc Aromat Compd Kleineidam S, Schüth C, Grathwohl P. Solubility-normalized 1997;9:1–4. combined pore-filling-partitioning sorption isotherms for Chaffee AL, Johns RB. PAHs in Australian coals. I. Angularly fused organic pollutants. Environ Sci Technol 2002;36:4689–97. pentacyclic tri- and tetraaromatic components of Victorian Klös H, Schoch C. Historical trends of sediment loads – memory of brown coal. Geochim Cosmochim Acta 1982;47:2141–55. an industrial region. Acta Hydrochim Hydrobiol 1993;21:32–7. Chapman PM, Downie J, Maynard A, Taylors LA. Coal and Kruge MA. Determination of thermal maturity and organic matter deodorizer residues in marine sediments – contaminants or type by principal components analysis of the distributions of pollutants? Environ. Toxicol Chem 1996;15:638–42. polycyclic aromatic compounds. Int J Coal Geol 2000;43:27–51. Chaulya SK. Assessment and management of air quality for an Kruge MA, Bensley DF. Flash pyrolysis-gas chromatography/mass opencast coal mining area. J Environ Manag 2004;70/1:1–14. spectrometry of Lower Kittanning vitrinites: changes in the Chen Y, Bi X, Mai B, Sheng G, Fu J. Emission characterization of distributions of polyaromatic hydrocarbons as a function of particulate/gaseous phases and size association for PAHs from coal rank. In: Mukhophadyay PK, Dow WG, editors. Vitrinite residential coal combustion. Fuel 2004;83:781–90. reflectance as a maturity parameter: applications and Costa HJ, Sauer TCJ. Forensics approaches and consideration in limitationsAmerican Chemical Society Symposium Series; identifying PAH background. Environ Forensics 2005;6:9–16. 1994. p. 136–48. Curran KJ, Irvine KN, Droppo IG, Murphy TP. Suspended solids, Külaots I, Hurt RH, Suuberg EM. Size distribution of unburnt trace metal and PAH concentrations and loadings from coal carbon in coal fly ash and its implications. Fuel pile runoff to Hamilton Harbour, Ontario. J Great Lakes Res 2004;83:223–30. 2000;26/1:18–30. Ligouis B, Kleineidam S, Karapanagioti HK, Kiem R, Grathwohl P, French PW. The impact of coal production on the sediment record Niemz C. Organic petrology: a new tool to study contaminants of the Severn Estuary. Environ Pollut 1998;103:37–43. in soils and sediments. In: Lichtfouse E, Schwarzenbauer J, Ghose MK. Generation and quantification of hazardous dusts from Robert D, editors. Environ. Chem. Germany: Springer Berlin coal mining in the Indian context. Environ Monit Assess Heidelberg; 2005. p. 89–98. 2007;130:35–45. Lima ALC, Farrington JW, Reddy CM. Combustion-derived Ghose MK, Majee SR. Assessment of the impact on the air polycyclic aromatic hydrocarbons in the environment – a environment due to opencast coal mining – an Indian case review. Environ Forensics 2005;6:109–31. study. Atmos Environ 2000a;34:2791–6. Liu G, Niu Z, Van Niekerk D, Xue T, Zheng L. Polycyclic aromatic Ghose MK, Majee SR. Sources of air pollution due to coal hydrocarbons (PAHs) from coal combustion: emissions, mining and their impact in Jharia coalfield. Environ Int analysis, and toxicology. Rev Environ Contam Toxicol 2000b;26:81–5. 2008;192:1–28. Given PH. The mobile phase in coals: its nature and modes of Lopez-Anton MA, Diaz-Somoano M, Martinez-Tarazona MR. release. Final report – Part 2, U.S. Department for Energy; 1987. Mercury retention by fly ashes from coal combustion: Gu X, Lin L, Zheng X, Zhang T, Song X, Wang J, et al. High influence of the unburnt carbon content. Ind Eng Chem Res prevalence of NTDs in Shanxi Province: a combined 2007;46:927–31. epidemiological approach. Birth defects research Massachusetts Institute of Technology. The future of coal – an Part A-clinical and molecular teratology, vol. 79; 2007. p. 702–7. interdisciplinary MIT study; 2007. free access at http://web.mit. Hayatsu R, Winans RE, Scott RG, Moore LP, Studier MH. Trapped edu/coal/. organic compounds and aromatic units in coals. Fuel Max-Planck-Institut für Plasmaphysik. Kohle in den USA/ Coal in 1978;57:541–8. the U. S. Energie-Perspektiven online journal, 03; 2000. http:// Hofmann T. An overview of factors influencing the colloid/particle www.ipp.mpg.de/ippcms/ep/ausgaben/ep200003/0300_ favoured relocation of contaminants. IAHS-AISH Publication; kohleusa_ep.html. 2002. p. 165–8. Max-Planck-Institut für Plasmaphysik. Kohle in China/ Coal in Hofmann T, Baumann T, Bundschuh T, Kammer Fvd, Leis A, China. Energie-Perspektiven online journal, 01; 2001a. http:// Schmitt D, et al. Aquatic colloids 1: definition and relevance – a www.ipp.mpg.de/ippcms/ep/ausgaben/ep200101/0101_ review. Grundwasser 2003a;8:203–10. kohlechina_ep.html. Hofmann T, Baumann T, Bundschuh T, Kammer Fvd, Leis A, Max-Planck-Institut für Plasmaphysik. Kohle in Indien/ Coal in Schmitt D, et al. Aquatic colloids 2: sampling and India. Energie-Perspektiven online journal, 03; 2001b. http:// characterization – a review. Grundwasser 2003b;8:213–23. www.ipp.mpg.de/ippcms/ep/ausgaben/ep200103/0301_ Hofmann T, Pies C, Yang Y. Elevated polycyclic aromatic kohle_indien_ep.html. hydrocarbons in a river flood plain soil due to mining activities. Max-Planck-Institut für Plasmaphysik. Kohle in Australien/ Coal Water Sci Technol: Water Supply 2007;7:69–77. in Australia. Energie-Perspektiven online journal, 01; 2002a. Hofmann T, Wendelborn A. Colloid facilitated transport of http://www.ipp.mpg.de/ippcms/ep/ausgaben/ep200201/ polychlorinated dibenzo-p-dioxins and dibenzofurans 0102_kohle_australien_ep.html. (PCDD/Fs) to the groundwater at Ma Da area, Vietnam. Max-Planck-Institut für Plasmaphysik. Kohle in Russland/ Coal in Environ Sci Pollut Res 2007;14:223–4. Russia. Energie-Perspektiven online journal, 04; 2002b. http:// Hofmann T, von der Kammer F. Estimating the relevance of www.ipp.mpg.de/ippcms/ep/ausgaben/ep200204/0402_ engineered carbonaceous nanoparticle facilitated transport of kohle_russland.html. 2472 SCIENCE OF THE TOTAL ENVIRONMENT 407 (2009) 2461– 2473

Meyers PA, Ishiwatari R. Lacustrine organic geochemistry—an plant detritus and of fossil woods, ambers and coals. Org overview of indicators of organic matter sources and Geochem 1986;10:877–89. diagenesis in lake sediments. Org Geochem 1993;20:867–900. Singh G, Sharma RK. A study of spatial distribution of air Micic V, Achten C, Schwarzbauer J, Hofmann T. Native PAHs in hard pollutants in some coal mining areas of Raniganj coalfield, coal particles as a possible source of increased PAH concentrations India. Environ Int 1992;18/2:191–200. in river sediments. Geochim. Cosmochim Acta 2007;15:A663. Stach E, Mackowsky MTh, Teichmüller M. Stach's Textbook of Coal Müller G, Grimmer G, Böhnke H. Sedimentary record of heavy Petrology. 3rd ed. Stuttgart, Germany: Borntraeger; 1982. metals and polycyclic aromatic hydrocarbons in Lake Stout SA, Wasielewski TN. Historical and chemical assessment of Constance. Naturwissenschaften 1977;64:427–31. the sources of PAHs in soils at a former coal burning power Murphy BL, Brown J. Environmental forensics aspects of PAHs plant, New Haven, Connecticut. Environ Forensics from wood treatment with creosote compounds. Environ 2004;5:195–211. Forensics 2005;6:151–9. Stout SA, Emsbo-Mattingly S. Concentration and character of Napier F, D'Arcy B, Jefferies C. A review of vehicle related metals PAHs and other hydrocarbons in coals of varying rank – and polycyclic aromatic hydrocarbons in the UK environment. Implications for environmental studies of soils and sediments Desalination 2008;226/1-3:143–50. containing particulate coal. Org Geochem 2008;39:801–19. Pies C, Yang Y, Hofmann T. Polycyclic aromatic hydrocarbon (PAH) Stout SA, Emsbo-Mattingly S, Uhler AD, McCarthy K. distribution in bank and alluvial soils of Mosel and Saar River. Environmental forensics particulate coal in soils and J Soils Sediments 2007;7:216–22. sediments – recognition and potential influences on Pies C, Hoffmann B, Petrowsky J, Yang Y, Ternes TA, Hofmann T. hydrocarbon fingerprinting and concentration. AEHS Characterization and source identification of polycyclic Magazine – Soil Sediment & Water (Environmental Forensics) aromatic hydrocarbons (PAHs) in river bank soils. June; 2002a. p. 12–5. Chemosphere 2008a;72:1594–601. Stout SA, Uhler AD, McCarthy KJ, Mattingly SE. Chemical Pies C, Ternes T, Hofmann T. Identifying sources of polycyclic fingerprinting of hydrocarbons. In: Murphy BL, Morrison RD, aromatic hydrocarbons (PAHs) in soils: distinguishing point and editors. Introduction to environmental forensics. Amsterdam, non-point sources using an extended PAH spectrum and Netherlands: Elsevier Academic Press; 2002b. p. 137–260. n-alkanes. J Soils Sediments 2008b;8:312–22. Suess MJ. The environmental load and cycle of polycyclic aromatic Püttmann W. Analysis of polycyclic aromatic hydrocarbons in hydrocarbons. Sci Tot Environ 1976;6:239–50. solid sample material using a desorption device coupled to a Suggate RP, Dickinson WW. Carbon NMR of coals: the effects of GC/MS system. Chromatography 1988;26:171–7. coal type and rank. Int J Coal Geol 2004;57:1–22. Püttmann W, Villar H. Occurrence and geochemical significance of Sun X, Ghosh U. The effect of activated carbon on partitioning, 1,2,5,6-tetramethylnaphthalene. Geochim Cosmochim Acta desorption, and biouptake of native polychlorinated biphenyls 1987;51:3023–929. in four freshwater sediments. Environ Toxicol Chem Püttmann W, Schaefer RG. Assessment of carbonization 2008;27:2287–95. properties of coals by analysis of trapped hydrocarbons. Tang D, Fermont WJ, Zhigui R, Püttmann W, Yang Q. Extraction Energy Fuels 1990;4:339–46. yields and GC/MS characteristics of extracts from high rank Radke M, Welte DH. The Methylphenanthrene Index (MPI): a coals and anthracites. Proceedings of the International maturity parameter based on aromatic hydrocarbons. Adv Org Conference on Coal Science, 16–20 September 1991. U. K.: Geochem 1981:504–12. University of Newcastle-upon-Tyne; 1991. Radke M, Welte DH, Willsch H. Geochemical study on a well in the Taylor GH, Teichmüller M, Davis A, Diessel CFK, Littke R, Robert P. western Canada Basin: relation of the aromatic distribution Organic petrology. Berlin-Stuttgart: Gebrüder Borntraeger; pattern to maturity of organic matter. Geochim Cosmochim A 1998. Germany. 1982a;46:1–10. Teichmüller M. The Genesis of coal from the standpoint of coal Radke M, Willsch H, Leythaeuser D. Aromatic compounds of coal: petrology. Int J Coal Geol 1989;12:1–87. relation of distribution pattern to rank. Geochim Cosmochim Thielemann T, Schmidt S, Gerling C. Lignite and hard coal: energy Acta 1982b;46:1831–48. suppliers for world needs until the year 2100 – an outlook. Int J Radke M, Leythaeuser D, Teichmüller M. Relationships between Coal Geol 2007;72:1–14. rank and composition of aromatic hydrocarbons for coals of Tissot BP, Welte DH. Petroleum formation and occurrence. Berlin: different origins. Org Geochem 1984;6:423–30. Springer Verlag; 1978. Germany. Radke M, Willsch H, Teichmüller M. Generation and distribution of Tremblay GA. Historical statistics support a hypothesis linking aromatic hydrocarbons in coals of low rank. Org Geochem tuberculosis and air pollution caused by coal. Int J Tuberc Lung 1990;15:539–63. Dis 2007;11/7:722–32. Saber D, Mauro D, Sirivedhin T. Environmental forensic Tripp BW, Farrington JW, Teal JM. Unburned coal as a source of investigation in sediments near a former manufactured gas hydrocarbons in surface sediments. Mar Pollut Bull plant site. Environ Forensics 2006;7:65–75. 1981;12:122–6. Schejbal-Chwastek M, Marszalek M. Mineralogical and chemical Tuo J, Philp RP. Saturated and aromatic diterpenoids and impact of anthropogenic emissions on soils and rocks on the triterpenoids in Eocene coals and mudstones from China. Appl Ojcow National Park (Poland). Geol Carpath 1999;50:409–12. Geochem 2005;20:367–81. Sekhar MC, Rao GA. Impact of opencast coal mining on the air Van Kooten GK, Short JW, Kolak JJ. Low-maturity Kulthieth environment. Eng Geol Environ 1997;1–3:2487–93. Formation coal: a possible source of polycyclic aromatic Short JW, Kvenvolden KA, Carlson PR, Hostettler FD, Rosenbauer hydrocarbons in benthic sediment of the Northern Gulf of RJ, Wright BA. Natural hydrocarbon background in benthic Alaska. Environ Forensics 2002;3:227–41. sediments of Prince William Sound, Alaska: Oil vs coal. Environ Van Krevelen DW. Coal, typology – physics – chemistry – Sci Technol 1999;33:34–42. constitution. 3rd ed. Amsterdam, The Netherlands: Elsevier Short JW, Irvine GV, Mann DH, Maselko JM, Pella JJ, Lindeberg MR, Science Publishers B. V.; 1993. et al. Slightly weathered Exxon Valdez oil persists in Gulf of Walker SE, Dickhut RM, Chisholm-Brause C, Sylva S, Reddy CM. Alaska beach sediments after 16 years. Environ Sci Technol Molecular and isotopic identification of PAH sources in a highly 2007;41:1245–50. industrialized urban estuary. Org Geochem 2005;36:619–32. Simoneit BRT, Grimalt JO, Wang TG, Cox RE, Hatcher RG, Wang Z. Forensic identification and differentiation of pyrogenic Nissenbaum A. Cyclic terpenoids of contemporary resinous PAHs from petrogenic PAHs. Proceedings The 21st SCIENCE OF THE TOTAL ENVIRONMENT 407 (2009) 2461– 2473 2473

International Symposium for Polycyclic Aromatic Compounds, Yang Y, Hofmann T, Pies C, Grathwohl P. Occurrence of coal and 05.–10.08.2007, Trondheim, Norway; 2007. coal-derived particle-bound polycyclic aromatic hydrocarbons Wang Z, Fingas M. Oil and petroleum product fingerprinting (PAHs) in a river floodplain soil. Environ Pollut 2007;151:121–9. analysis by gas chromatographic techniques. In: Nollet LML, Yang Y, Cajthaml T, Hofmann T. PAH desorption from river editor. Chromatographic analysis of the environment. Boca floodplain soils using supercritical fluid extraction. Environ Raton, U.S.: Taylor & Francis; 2006. p. 1028–98. Pollut 2008a;156:745–52. Wang G, Kleineidam S, Grathwohl P. Sorption/desorption Yang Y, Ligouis B, Pies C, Achten C, Hofmann T. Identification of reversibility of phenanthrene in soils and carbonaceous carbonaceous geosorbents for PAHs by organic petrography in materials. Environ Sci Technol 2007;41:1186–93. river floodplain soils. Chemosphere 2008b;71:2158–67. Werner D, Ghosh U, Luthy RG. Modeling polychlorinated biphenyl Yang Y, Hofmann T, Pies C, Grathwohl P. Sorption of polycyclic mass transfer after amendment of contaminated sediment aromatic hydrocarbons (PAHs) to carbonaceous materials in a with activated carbon. Environ Sci Technol 2006;40:4211–8. river floodplain soil. Environ Pollut 2008c:1357–63. White CM, Lee ML. Identification and geochemical significance of Zhao ZB, Liu K, Xie W, Pan WP, Riley JT. Soluble polycyclic aromatic some aromatic components of coal. Geochim Cosmochim Acta hydrocarbons in raw coals. J Hazard Mater 2000;73:77–85. 1980;44:1825–32. Zimmermann JR, Gosh U, Millward RN, Bridges TS, Luthy RG. Willsch H, Radke M. Distribution of polycyclic aromatic Addition of carbon sorbents to reduce PCB and PAH compounds in coals of high rank. Polycyc Aromat Comp bioavailability in marine sediments: physicochemical tests. 1995;7:231–51. Environ Sci Technol, 2004;38:5458–64. World Coal Institute. Top ten hard coal producing countries worldwide, 2004; 2007. http://www.worldcoal.org.