Marine Pollution Bulletin 58 (2009) 189–200

Contents lists available at ScienceDirect

Marine Pollution Bulletin

journal homepage: www.elsevier .com/ locate /marpolbul

Sources of sedimentary PAHs in tropical Asian waters: Differentiation betweenpyrogenic and petrogenic sources by alkyl homolog abundance

Mahua Saha a, Ayako Togo a, Kaoruko Mizukawa a, Michio Murakami a, Hideshige Takada a,*,Mohamad P. Zakaria b, Nguyen H. Chiem c, Bui Cach Tuyen d, Maricar Prudente e,Ruchaya Boonyatumanond f, Santosh Kumar Sarkar g, Badal Bhattacharya h,Pravakar Mishra i, Touch Seang Tana j

a Laboratory of Organic Geochemistry (LOG), Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japanb Faculty of Science and Environmental Studies, Universiti Putra Malaysia, Malaysiac College of Agriculture, Can Tho University, Vietnamd Nong Lam University, Ho Chi Minh City, Vietname Science Education Department, De La Salle University, Manila, Philippinesf Environmental Research and Training Center, Bangkok, Thailandg Department of Marine Science, University of Calcutta, Kolkata, Indiah Institute of Ecotoxicology and Environmental Sciences, Kolkata, Indiai Department of Ocean Development, Government of India, NIOT Campus, Chennai, Indiaj Economic, Social and Cultural Observation Unit, Phnom Penh, Cambodia

0025-326X/$ - see front matter � 2008 Elsevier Ltd. Adoi:10.1016/j.marpolbul.2008.04.049

* Corresponding author. Tel.: +81 42 367 5825; faxE-mail address: shige@cc.tuat.ac.jp (H. Takada).

a b s t r a c t

We collected surface sediment samples from 174 locations in India, Indonesia, Malaysia, Thailand, Viet-nam, Cambodia, Laos, and the Philippines and analyzed them for polycyclic aromatic hydrocarbons(PAHs) and hopanes. PAHs were widely distributed in the sediments, with comparatively higher concen-trations in urban areas (

PPAHs: �1000 to �100000 ng/g-dry) than in rural areas (�10 to �100 g-dry),

indicating large sources of PAHs in urban areas. To distinguish petrogenic and pyrogenic sources of PAHs,we calculated the ratios of alkyl PAHs to parent PAHs: methylphenanthrenes to phenanthrene (MP/P),methylpyrenes + methylfluoranthenes to pyrene + fluoranthene (MPy/Py), and methylchrysenes + meth-ylbenz[a]anthracenes to chrysene + benz[a]anthracene (MC/C). Analysis of source materials (crude oil,automobile exhaust, and coal and wood combustion products) gave thresholds of MP/P = 0.4,MPy/Py = 0.5, and MC/C = 1.0 for exclusive combustion origin. All the combustion product samples hadthe ratios of alkyl PAHs to parent PAHs below these threshold values. Contributions of petrogenic andpyrogenic sources to the sedimentary PAHs were uneven among the homologs: the phenanthrene serieshad a greater petrogenic contribution, whereas the chrysene series had a greater pyrogenic contribution.All the Indian sediments showed a strong pyrogenic signature with MP/P � 0.5, MPy/Py � 0.1, and MC/C � 0.2, together with depletion of hopanes indicating intensive inputs of combustion products of coaland/or wood, probably due to the heavy dependence on these fuels as sources of energy. In contrast, sed-imentary PAHs from all other tropical Asian cities were abundant in alkylated PAHs with MP/P � 1–4,MPy/Py � 0.3–1, and MC/C � 0.2–1.0, suggesting a ubiquitous input of petrogenic PAHs. Petrogenic con-tributions to PAH homologs varied among the countries: largest in Malaysia whereas inferior in Laos. Thehigher abundance of alkylated PAHs together with constant hopane profiles suggests widespread inputsof automobile-derived petrogenic PAHs to Asian waters.

� 2008 Elsevier Ltd. All rights reserved.

1. Introduction

Polycyclic aromatic hydrocarbons (PAHs) form one of the mostimportant classes of persistent pollutants (Blumer, 1976). SomePAHs are carcinogenic and mutagenic. Owing to their toxicityand widespread distribution around the globe, identification of

ll rights reserved.

: +81 42 360 8264.

the sources of PAHs is important. There are two types of anthropo-genic sources of PAHs: petrogenic and pyrogenic. Petrogenicsources include crude oil and petroleum products such as kero-sene, gasoline, diesel fuel, lubricating oil, and asphalt. Pyrogenicsources form by the incomplete combustion of organic matter(e.g., coal, petroleum, and wood) in industrial operations andpower plants that use fossil fuels, smelting, garbage incinerators,vehicle engines powered by gasoline or diesel fuel, and forest fires.PAHs are also derived from some natural sources such as oil seeps,

PHILIPPINES

INDONESIA

MALAYSIA

VIETNAM

LAOS

CAMBODIATHAILAND

INDIAManila

Jakarta

Kuala Lumpur

Ho Chi Minh

Phnom PenhBangkok

Vientiane

Kolkata

0º

15º N

120º105º90º75º E

Fig. 1. Study area and investigated countries.

190 M. Saha et al. / Marine Pollution Bulletin 58 (2009) 189–200

ancient sediment erosion, and early diagenesis. However, in manyareas affected by human activities, natural sources are over-whelmed by anthropogenic sources of all PAHs except perylene.

The distributions of PAHs in sediments have been studied sincethe mid-1970s. PAHs are distributed globally, from inland lakesand urban rivers to the open ocean, over a wide range of concentra-tions. Most studies of their distribution in aquatic sediments havebeen conducted in industrialized countries, e.g., England (Wood-head et al., 1999), the USA (Hites et al., 1980; Simcik et al., 1996;Zeng and Vista, 1997; Pereira et al., 1999; Stout et al., 2004), Eur-ope (Lipiatou and Saliot, 1991; Wakeham, 1996; Budzinski et al.,1997; Notar et al., 2001), and Australia (McCready et al., 2000).They found that pyrogenic PAHs predominate. Very few reportsindicate the predominance of petrogenic PAHs (Eganhouse andGossett, 1991; Bence et al., 1996; Boehm et al., 1998), which weremostly associated with accidental oil spills or were localized. Pyro-genic sources predominated in the East China Sea (Guo et al.,2006), whereas both sources were comparable in the coastal sedi-ment of the Pearl River, China (Bixian et al., 2001). However, verylimited information on the environmental distribution of PAHs intropical Asia is available, although industrialization and urbaniza-tion have proceeded rapidly during the last few decades, and theassociated increase in PAHs is of concern in this region. Recently,Zakaria et al. (2002) demonstrated the widespread input of petro-genic PAHs to Malaysian waters. They suggested that the frequentheavy rain inherent to tropical Asia may facilitate the transfer ofleaked petroleum from land to rivers and coastal waters. This com-bination of socio-economic and climatic conditions is likely to becommon across tropical Asia.

The identification of PAH sources is requisite to regulation ofthe input of PAHs to waters. The initial step in source identificationis differentiation between petrogenic and pyrogenic sources, whichis relevant to the impacts of PAH accumulation on aquatic and ben-thic ecosystems. Petrogenic PAHs may be more available for bio-logical uptake than pyrogenic PAHs (Farrington et al., 1983),since it tends to bind more strongly to sedimentary particles(McGroddy and Farrington, 1995; Gustafsson et al., 1997). Hence,to evaluate the risks of PAHs to aquatic biota, source-distinctionis essential.

There have been proposed many molecular markers to identifycontribution from sources of PAHs. Some unique compounds, spe-cific to certain fuels have been reported. For example, retene (Ram-dahl, 1983), 1,7-dimethylphenanthrene (Benner et al., 1995) havebeen proposed as tracers of wood combustion. However, any uni-versal compounds generated through all the fuels for combustion(e.g., biomass, coal, and petroleum) have not been reported. Oneapproach is to focus on the difference in thermodynamic stabilityamong PAH species to distinguish pyrogenic and petrogenic PAHs.Thermodynamically stable species of PAHs are enriched in com-bustion products because thermodynamically unstable species dis-appear during combustion. Alkylated PAHs are thermodynamicallyunstable than the corresponding parent PAHs and, therefore, theratio of alkyl PAHs to parent PAHs has been used for source differ-entiation of PAHs (Youngblood and Blumer, 1975; Blumer, 1976;Garrigues et al., 1995). The ratio of alkylphenanthrenes to phenan-threnes (MP/P) has been used to distinguish petrogenic and pyro-genic sources of PAHs in many studies (Eganhouse and Gossett,1991; Lipiatou and Saliot, 1991; Garrigues et al., 1995; Budzinskiet al., 1997; Zeng and Vista, 1997; Pereira et al., 1999; Wanget al., 1999; Notar et al., 2001; Yunker et al., 2002; Zakaria et al.,2002; Boonyatumanond et al., 2007). But MP/P ratio is explainingonly the phenanthrene group of PAHs which is only one part of to-tal PAHs. There are some other homolog series including fluoranth-ene–pyrene group and chrysene–benz[a]anthracene group andindividual homologs sometimes have different sources. To makeour source-distinction more superlative we expanded our study

taking into account the fluoranthene–pyrene series and chry-sene–benz[a]anthracene series along with the phenanthrene seriesin the present study.

To identify the sources of the petrogenic PAHs in detail, we in-cluded hopanes, a group of pentacyclic triterpane hydrocarbons.Hopanes are produced through diagenesis during petroleum for-mation in sedimentary bed and are ubiquitously present in crudeoil. Owing to their high boiling points, they are not present in gas-oline and diesel fuel but are found in lubricating oils, asphalt, andheavy residual oils. Hopanes consist of a range of homologs fromC27 to C35, with various stereo isomers (Peters et al., 2005). Theircompositions vary in crude oils, depending on their origin (e.g.,the sources of organic matter and the depositional environment)and the maturity of the oil (Volkman et al., 1997; Luellen and Shea,2003). The hopane distributions of most of the source oils have avery distinct signature that is conserved even in highly weatheredoils which shows their persistent nature in the environment(Prince et al., 1994; Wang et al., 1994). Hence this petroleum bio-marker often provides a fingerprint to identify source oils and allo-cate source contributions towards the aquatic environment(Volkman et al., 1997). Compositional indices of hopanes (e.g., a ra-tio of 17a,21b(H)-hopane to 17a,21b(H)-30-norhopane: C30/C29,17a-22,29,30-trisnorhopane/18a-22,29,30-trisnorneohopane: Tm/Ts)were utilized to distinguish tar ball derived from the 1989 ExxonValdez oil spill from background oil pollution in Prince WilliamSound, Alaska (Kvenvolden et al., 1995). Finger-printing of hopaneswas also applied to give an evidence of an important contributionof road asphalt particles to sedimentary hydrocarbons in riverinesystem in the Alsace–Lorraine region, France (Faure et al., 2000).Therefore based on the examination of hopane concentration andthe profile of its homologs, we can validate the presence and sortof petrogenic PAHs in sediments.

The purposes of this study are (1) to evaluate several parame-ters of alkylated PAHs in order to establish criteria for discrimina-tion of PAH sources; (2) to investigate the PAH pollution status insediments in a wide range of tropical Asian countries; and (3) todistinguish the sources of the sedimentary PAHs on the basis ofour established criteria.

2. Samples and analytical methods

Surface sediment samples were collected from canals, rivers, alake, and coastal environments in eight tropical Asian countries:India (n = 38), Indonesia (n = 10), Malaysia (n = 34), Thailand(n = 35), Vietnam (n = 19), Cambodia (n = 19), Laos (n = 9), andthe Philippines (n = 10) in 2000–2007, as shown in Fig. 1. The sam-ples were collected from populated cities and rural areas in eachcountry. For comparison, samples were collected from Tokyo Bay,Japan, and adjacent canals (n = 24) in 2004–2006. Maps and details

m/z = 202PyrFluo

m/z = 216

x

ya

bc

d

Retention time (min)

Sele

cted

ion

curre

nt

m/z = 228ChryBaA

m/z = 242 e

fg h

Retention time (min)

Sele

cted

ion

curre

nt

i

m/z = 178

Anth

Phe

m/z = 192 3 2 91

Retention time (min)

Sele

cted

ion

curre

nt

Retention time (min)

Sele

cted

ion

curre

ntAnth

Phe Pyr

Fluo

ChryBaA

BbFBFs

BaPBePPery

IndPyBghiP

Cor

m/z = 178+ 202 + 228 + 252 +276 +300a

b

c

d

Fig. 2. Reconstructed ion chromatograms for parent PAHs (a), methylphenanthrenes (b), methylpyrenes/fluoranthenes (c), methylchrysenes/benz[a]anthracene (d). Sample:PR1 (the Philippines).

M. Saha et al. / Marine Pollution Bulletin 58 (2009) 189–200 191

are available in Supporting Information (Fig. S1, Table S1). Riverand estuarine sediments (top 0–5 cm) were collected by using anEkman dredge. Coastal sediments (top 0–2 cm) were collected byusing a Smith–McIntyre sampler. The samples were stored at�30 �C and freeze-dried before analysis.

Five crude oil samples were obtained from a worldwide collec-tion of samples held by the Japanese Coast Guard. Eight soot sam-ples were collected from two gasoline-powered cars (called Auto),three diesel-powered taxis, and three diesel-powered buses inKolkata, India, by scraping the inner wall of the exhaust pipes with

192 M. Saha et al. / Marine Pollution Bulletin 58 (2009) 189–200

a stainless steel spoon. Two types of soot samples were scrapedfrom the bottom of cooking pans where coal and wood were com-busted for cooking separately. Four soot samples from each type ofcombustion (coal and wood) were collected from food shops inKolkata and houses in nearby villages, respectively. Three samplesof soot from brick manufacturing were scraped from the innerwalls of chimneys at brick factories near Kolkata, which burn coalto acquire high temperature.

Details of the extraction and purification procedures were de-scribed elsewhere (Zakaria et al., 2001; Boonyatumanond et al.,2006). Briefly, freeze-dried sediment samples and soot sampleswere extracted in a Dionex ASE 200 accelerated solvent extractorwith a mixture of dichloromethane (DCM) and acetone (3:1, v/v).The crude oil samples were dissolved in DCM. The extracts andsolutions were spiked with deuterated PAHs (anthracene-d10, p-terphenyl-d14, and benz[a]anthracene-d12) as surrogates and puri-fied by 2-step silica gel column chromatography. The alkane + ho-pane fraction and PAH fraction were analyzed by a gaschromatograph equipped with a quadrupole mass-selective detec-tor (GC–MS; Agilent HP5890, HP5972) as described (Boonyatu-manond et al., 2006).

In the present study 14 parent PAH species and 12 methylatedPAH species were quantified. The parent PAHs and their abbrevia-tion in bracket are as follows: phenanthrene (Phe), anthracene(Anth), fluoranthene (Fluo), pyrene (Pyr), benz[a]anthracene (BaA),chrysene (Chry), benzo[b]fluoranthene (BbF), benzo[j]fluoranth-ene + benzo[k]fluoranthene (BFs), benzo[e]pyrene (BaP), benzo[a]-pyrene (BeP), indeno[1,2,3-cd]pyrene (IndPy), benzo[ghi]perylene(BghiP), and coronene (Cor). On GC–MS, they were monitored atm/z = 178 (phenanthrene, anthracene), m/z = 202 (fluoranthene,pyrene), m/z = 228 (benz[a]anthracene, chrysene), m/z = 252(benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[k]fluoranth-ene, benzo[e]pyrene, benzo[a]pyrene, perylene), m/z = 276(indeno[1,2,3-cd]pyrene, benzo[ghi]perylene), and m/z = 300 (cor-onene). Typical mass fragmentgram for the parent PAH species areshown in Fig. 2a. Their identification was based on mass spectrum,comparison of the retention time with corresponding authenticstandard and/or retention indices listed in Lee et al. (1979).

Four isomers of methylphenanthrenes were monitored atm/z = 192. Mass fragmentgram at m/z = 192 showed fourprominent peaks, as shown in Fig. 2b and they were identified as3-methylphenanthrene (3-MP), 2-methylphenanthrene (2-MP),9-methylphenanthrene (9-MP), 1-methylphenanthrene (1-MP) inthe order of elution. The identification was based on the compari-son of retention time with an authentic standard (1-MP) and ofretention indices listed in Lee et al. (1979) and Takada et al.(1990). Because anthracene is a minor component and their alkyl-ated homologs are not positively identified in environmental sam-ples (Takada et al., 1990). Thus, methylanthracenes were not usedfor the source-discrimination in the present study. Methylpyrenesand/or methylfluoranthenes were monitored at m/z = 216.Although normally six peaks were observed on the mass fragment-gram at m/z = 216 (Fig. 2c), three peaks (i.e., peaks ‘‘b”, ‘‘c”, and ‘‘d”)were identified as methylpyrenes and/or methylfluoranthenes.Based on the accordance of retention time of peak ‘‘d” with thatof authentic standard, peak ‘‘d” was assigned as 1-methylpyrene.The comparison of retention indices listed in Lee et al. (1979) ten-tatively identified peak ‘‘b” and peak ‘‘c” as 4-methylpyrene and 2-methylpyrene, respectively. It was proved that benzo[a]fluoreneand benzo[b]fluorene were coeluted as peak ‘‘y” and peak ‘‘a”, bycoinjection of their authentic standards. Regarding peak ‘‘x”, nei-ther methylpyrenes nor methylfluoranthenes was eluted in thecorresponding range of retention indices (Lee et al., 1979). Conse-quently, peaks ‘‘b”, ‘‘c” and ‘‘d” were quantified as methylpyrenesand/or methylfluoranthenes in the present study. Methylchrysenesand/or methylbenz[a]anthracenes were monitored at m/z = 242.

Major five peaks (i.e., peaks ‘‘e”, ‘‘f”, ‘‘g”, ‘‘h”, and ‘‘i”) were quanti-fied as methylchrysenes and/or methylbenz[a]anthracenes(Fig. 2d). Based on the accordance of retention time of peak ‘‘i” withthat of authentic standard, peak ‘‘i” was assigned as 1-methylchry-sene. For the other four peaks, identification of positions of methylsubstitution was not made, because retention indices suggest morethan 10 candidates (Lee et al., 1979).

Individual PAHs were quantified by comparing the integratedpeak area of the selected ion with the peak area of internal injec-tion standard (IISTD). Acenaphthene-d8 and chrysene-d12 wereused as IISTD for the quantification of PAHs ranging from phenan-threne to 1-methylphenanthrene and for PAHs from fluorantheneto coronene, respectively. Corrections for relative response at thecorresponding mass/charge ratio were made by analyzing a PAHstandard (phenanthrene, anthracene, 1-methylphenanthrene,fluoranthene, pyrene, 1-methylpyrene, chrysene, 1-methylchry-sene, 5-methylchrysene, benzo[b]fluoranthene, benzo[e]pyrene,benzo[a]pyrene, perylene, benzo[ghi]perylene, coronene) underthe same instrumental conditions like the sample analyses. Nobenz[a]anthracene standard was available, therefore an estimatedresponse factor for benz[a]anthracene was based on a response forchrysene. Similarly, benzo[j]fluoranthene + benzo[k]fluorantheneand indeno[1,2,3-cd]pyrene concentrations were based on thebenzo[b]fluoranthene and benzo[ghi]perylene response, respec-tively. Also all the methylphenanthrenes, methylpyrenes andmethylfluoranthenes, methylchrysenes and methylbenz[a]anthra-cenes were based on the 1-methylphenanthrene, 1-methylpyrene,and average of 1-methylchrysene and 5-methylchrysene respec-tively. PAHs concentrations were recovery-corrected using thespiked surrogates. Concentrations of PAHs ranging from phenan-threne to 1-methylphenanthrene, from fluoranthene to 1-meth-ylpyrene and from benz[a]anthracene to coronene werecorrected by recovery of anthracene-d10, p-terphenyl-d14 andbenz[a]anthracene-d12, respectively. Results were recovery-cor-rected with the recoveries of the surrogates (>80% throughoutthe analyses). We tested the reproducibility of the analyses by fourreplicate analyses of sediment; reproducibility ranged from 2.3% to14.6% of the relative standard deviation. Procedural blanks wererun with every batch, and analytical values 5 times higher thanthe blank were considered significant.

The sum of concentrations of 14 parental PAH species rangingfrom phenanthrene to coronene, excluding perylene, is expressedas ‘‘total parent PAHs” or ‘‘

P14PAHs”. The sum of concentrations

of all 26 PAH species except perylene is expressed as ‘‘P

26PAHs”.Because we measured four methylated phenanthrenes in additionto the 14 parental PAHs in our previous papers (Zakaria et al.,2002), the sum of the 18 PAH species is expressed as ‘‘

P18PAHs”

to facilitate comparison. The ratio of the sum of 3-methylphe-nanthrene, 2-methylphenanthrene, 9-methylphenanthrene and 1-methylphenanthrene to phenanthrene is expressed as ‘‘MP/P”.The ratio of the sum of three peaks of methylpyrenes/methylfluo-ranthenes to the sum of pyrene and fluoranthene is expressed as‘‘MPy/Py”. The ratio of the sum of five peaks of methylchrysenes/methylbenz[a]anthracenes to the sum of chrysene andbenz[a]anthracene is expressed as ‘‘MC/C”. In addition, the ratioof the sum of all the methyl PAH species to the sum of phenan-threne, fluoranthene, pyrene, chrysene and benz[a]anthracene isdefined as ‘‘MPAHs/PAHs”.

Individual hopanes were identified by comparison of theirretention times with those for the standards and their mass spec-tra, which were obtained on a different GC–MS run on Scan mode,or in literature. Triterpanes, including hopanes, were monitored ata mass/charge ratio (m/z) of 191 in selected ion monitoring mode.17a(H)-22,29,30-trisnorhopane (Tm), 17a(H),21a(H)-norhopane(C29 17a), 17b(H),21a(H)-norhopane (C29 17b), 17a(H),21b(H)-ho-pane (C30 17a), 17b(H),21a(H)-hopane (C30 17b), 18a(H)-oleanane,

Fig. 3. Concentrations of total parent PAHs in sediments from tropical Asiancountries in comparison to those in Tokyo, Japan and in world rivers, lakes andcoastal zones. Data for global sediments are derived from Boonyatumanond et al.(2006). Cross: urban locations; square: rural locations; short vertical line: global.Total parent PAHs = Sum of 14 parent PAHs (phenanthrene, anthracene, fluaranth-ene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[j]fluoranth-ene, benzo[k]fluoranthene, benzo[e]pyrene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, benzo[ghi]perylene, and coronene).

M. Saha et al. / Marine Pollution Bulletin 58 (2009) 189–200 193

18b(H)-oleanane), and 17a(H),21b(H)-homohopane (C31 17a)were used as analytical standards. Individual hopanes were quan-tified by comparing the integrated peak area of the selected ionwith the peak area of IISTD (17b,21(H)b-hopane). Response factorof 18a(H)-22,29,30-trisnorneohopane (Ts) was assumed to be thesame as Tm, 18a(H),21b(H)-30-norhopane (C29 18a) as C29 17b,and homohopanes ranging from C31 to C35 of carbon number asC31 17a.

3. Results and discussion

3.1. Establishment of criteria for source identification

The relative abundance of alkylated PAH is convenient forsource-distinction, since as temperature increases the abundanceof alkyl side chains in PAHs decreases (Blumer, 1976; Garrigueset al., 1995). Alkyl-substituted (alkylated) PAHs are formed atlow temperatures (�100–150 �C), while trace amounts are formedat higher temperatures (�2000 �C) (Blumer, 1976). Parent PAHs arethermodynamically more stable than alkylated PAHs. Therefore, incombustion products formed at high temperatures, alkylated PAHsare depleted, whereas in petroleum, which is diagenetically gener-ated at low temperatures in the crust, they are abundant.

Values of MP/P, MPy/Py, MC/C, and MPAHs/PAHs in the sourcematerials are reported in Table 1. The petrogenic sources havehigher value of ratios than the pyrogenic sources. Crude oil hashighest values of MP/P (2.43–4.34), MPy/Py (0.84–2.82), andMC/C (2.14–2.95). Most values were >2. The next highest valuescame from soot collected from automobiles: MP/P = 0.42–3.38,MPy/Py = 0.13–1.41, MC/C = 0.08–1.77. These values show a petro-

Table 1PAHs and hopanes in crude oil, automobile soots, soots from brick manufacturing and coo

Type ofsamples

SampleID

Total PAHs(ng/g-dry)

MP/P

MPy/Py

MC/C

MPAHs/PAHs

Pyr/Fluo

F(

Crude oil UmmShaif

700 4.34 2.41 2.74 3.98 1.07 0

Marban 339 3.88 2.82 2.90 3.66 1.76 0Labuan 3060 2.43 0.84 2.53 2.35 0.90 0Miri 480 2.45 1.49 2.14 2.24 1.65 0Tapis 946 3.17 1.31 2.95 3.04 0.73 0

SootAutomobile S-2 Bus 140 0.42 0.16 0.14 0.27 1.69 0

S-3 Bus 73 0.78 0.40 0.08 0.47 1.90 0S-12Bus

158 2.89 0.53 0.34 0.77 3.65 0

S-4Taxi

1259 1.12 0.22 0.19 0.31 1.62 0

S-6Taxi

721 1.05 0.13 0.10 0.20 1.40 0

S-13Taxi

228 1.51 0.16 0.26 0.46 1.27 0

S-8Auto

219 3.38 1.41 1.77 2.05 2.94 0

S-9Auto

588 1.45 0.26 0.71 0.51 2.46 0

Cooking(coal)

S-2 41 0.20 0.07 0.12 0.14 0.88 0S-5 77 0.31 0.48 1.01 0.83 1.44 0S-6 575 0.43 0.25 0.19 0.23 1.42 0S-7 1649 0.36 0.21 0.37 0.31 1.24 0

Cooking(wood)

WS1 520 0.16 0.07 0.10 0.11 0.82 0WS2 1628 0.07 0.05 0.06 0.05 1.06 0WS5 82 0.12 0.03 0.07 0.07 0.70 0WS8 721 0.14 0.06 0.07 0.09 0.80 0

Brickmanufact.

Ut 98 0.06 0.02 0.09 0.05 0.51 0Kn 78 0.03 0.01 0.07 0.03 0.27 0Hm 96 0.03 0.01 0.06 0.03 0.23 0

ND: Cannot be detected because of zero value of denominator.

genic signature of automobile soot. Although the soot results fromcombustion, the petrogenic signature is likely due to the presenceof crankcase oil and unburnt fuel. As indicated by previousresearchers (Rogge et al., 1993; Boonyatumanond et al., 2007),benzo[ghi]perlylene was more abundant in soot from gasoline-engine-equipped vehicles than that from diesel ones. Relative

king soots.

luo/Fluo + Pyr)

Phe/Anth

Anth/(Anth + Phe)

BaA/(BaA + Chry)

IP/(IP + BghiP)

C30 hopane/Total PAHs

.48 ND 0.00 0.00 0.11 0.2043

.36 ND 0.00 0.05 0.01 0.1593

.53 72.59 0.01 0.23 0.27 0.0526

.38 3.60 0.22 0.32 0.25 0.7625

.58 32.52 0.03 0.13 0.00 0.1533

.37 15.29 0.06 0.30 0.39 0.0132

.35 9.96 0.09 0.29 0.30 0.0316

.22 4.64 0.18 0.17 0.32 0.0687

.38 5.32 0.16 0.41 0.43 0.0367

.42 3.98 0.20 0.25 0.51 0.0160

.44 6.80 0.13 0.24 0.39 0.1841

.25 5.43 0.16 0.28 0.10 0.6562

.29 4.74 0.17 0.38 0.18 0.4031

.53 4.53 0.18 0.53 0.43 0.0001

.41 6.88 0.13 0.33 0.26 0.0005

.41 3.57 0.22 0.34 0.49 0.0001

.45 3.99 0.20 0.44 0.45 0.0001

.55 4.65 0.18 0.48 0.47 0.0000

.49 3.30 0.23 0.52 0.48 0.0000

.59 11.07 0.08 0.36 0.54 0.0001

.56 4.54 0.18 0.48 0.51 0.0000

.66 21.44 0.04 0.35 0.43 0.0001

.78 120.13 0.01 0.22 0.44 0.0001

.82 66.14 0.01 0.18 0.50 0.0001

194 M. Saha et al. / Marine Pollution Bulletin 58 (2009) 189–200

abundance of this compound could be an index for estimation ofautoexhaust contribution from gasoline-engine. The soot samplestaken from coal and wood combustion for cooking, tend towardpyrogenic and have lower values of the above ratios than that ofautomobile soot. Whereas between the coal and wood combustion,the coal combustion soot shows higher MP/P (0.2–0.43), MPy/Py(0.07–0.48), MC/C (0.12–1.01) values than wood combustionsoot which have MP/P = 0.07–0.16, MPy/Py = 0.03–0.07 andMC/C = 0.06–0.10, respectively (Table 1). Similar result was alsoobserved by Lee et al. (1977), where they found a relatively higherconcentration of alkylated PAHs in coal combustion products ascompared to wood combustion. Also high molecular weight PAHswere more abundant in coal combustion soot than wood one, asshown in Fig. 6. The lowest values were detected in soot from brickmanufacturing: MP/P = 0.03–0.06, MPy/Py = 0.01–0.02, MC/C = 0.06–0.09. These values were much lower than those in coalcombustion cooking soot, even though both processes use coal assource of fuel. The minimal contents of hopanes in the cooking sootsamples (Table 1), which were comparable to those in the sootfrom brick manufacturing, confirm the absence of petroleumsources. The difference can be explained by temperature: bricks

Fig. 4. (a) Sedimentary PAH profiles for rural locations in tropical Asian countries. (b) Sedto that in Tokyo, Japan.

are made at temperatures above 600–1100 �C, whereas cookinguses temperatures of 100–300 �C. Since the abundance of alkyl sidechains decreases with increasing temperature, brick soot had lowerratios of alkylated PAHs. Using the highest ratios of alkylated PAHsto parent PAHs in the pyrogenic source materials (i.e., cooking sootand brick soot), we selected threshold values of MP/P = 0.4, MPy/Py = 0.5, MC/C = 1.0, and MPAHs/PAHs = 0.8, below which PAHsare identified as exclusively pyrogenic.

Many other compositional parameters have been used for thedifferentiation of petrogenic and pyrogenic sources, including theratios of pyrene to fluoranthene (Pyr/Fluo), anthracene to anthra-cene + phenanthrene (Anth/Anth + Phe), benz[a]anthracene tobenz[a]anthracene + chrysene (BaA/BaA + Chry), and indenopyreneto indenopyrene + benzo[ghi]perylene (IP/IP + BghiP) (Bixian et al.,2001; Yunker et al., 2002; Guo et al., 2006). We examined thevalidity of these ratios for source differentiation with our sourcematerials (Table 1). Although they are usable for source-distinc-tion, they are not definitive, since there are many exceptions. Forexample, although most of the crude oil samples have Pyr/Fluo > 1,showing a petrogenic source, some (Labuan, Tapis) have Pyr/Fluo < 1 and one wood soot sample (WS2) have Pyr/Fluo > 1 (i.e

imentary PAH profiles for urban locations in tropical Asian countries in comparison

Fig. 4 (continued)

M. Saha et al. / Marine Pollution Bulletin 58 (2009) 189–200 195

petrogenic). Similarly, one crude oil sample (Miri) has Anth/(An-th + Phe) > 0.1 and BaA/(BaA + Chry) � 0.35, implying a pyrogenicsource and one wood soot sample (WS5) having Anth/(An-th + Phe) < 0.1, shows a petrogenic source of PAHs. All brick manu-facturing soot samples and most cooking soot samples with strongpyrogenic characteristics show IP/(IP + BghiP) < 0.5 (i.e., petrogen-ic). Hence, these ratios can give a rough idea of the source, but theyare not authoritative enough to be exact.

3.2. Levels of PAHs in surface sediments

PAHs were widely distributed in the tropical Asian sediments atconcentration ranges for

P26 PAHs of 4–42900 ng/g-dry, for

P18PAHs of 4–40500 ng/g-dry, and for

P14 PAHs (i.e. only 14

parent PAHs) of 4–38100 ng/g-dry (Table S2).P

14 PAHs is usedas total PAHs in this paper to facilitate the comparison of our datawith those reported by many researchers who normally measured

196 M. Saha et al. / Marine Pollution Bulletin 58 (2009) 189–200

parental PAHs. Perylene was excluded from theP

PAHs because ithas natural origins and was abundant in samples collected fromthe rural areas, and we focused on anthropogenic sources. TheP

PAH concentrations are comparable with those in Tokyo, Japanand in other industrialized countries (Fig. 3). Sediments collectedwithin and near populated cities had higher PAH concentrations(mean, 11300 ± 12100 ng/g; range, �100 to near 100000 ng/g)than those in rural areas (mean, 35 ± 13 ng/g; range, �10 to�100 ng/g). This indicates the presence of strong PAH sources inthe urban areas. Low but significant concentrations of PAHs werespread all over tropical Asia.

Among the urban areas, the highest PAH concentrations werefound in India (mean, 11300 ng/g, n = 17), and the lowest inMalaysia (206 ng/g, n = 17). The other countries showed moderatevalues: Laos (1020 ng/g, n = 5), Cambodia (1760 ng/g, n = 4), Viet-nam (1540 ng/g, n = 13), Thailand (1120 ng/g, n = 17), the Philip-pines (1410 ng/g, n = 6), and Indonesia (1300 ng/g, n = 4). ThePAH concentrations in the urban areas of all countries except Indiawere slightly lower than those in Tokyo, Japan (3430 ng/g: n = 24).This lower value of PAHs could be the effect of dilution by erodedsoil. Normally in tropical Asian countries, frequent heavy rainsupplies much more eroded soil particles, diluting PAHs, than inTokyo, Japan. Even so, with such dilution, the higher PAH concen-trations in India than Tokyo, Japan suggest much larger inputs ofPAHs in this tropical Asian country than in Tokyo, Japan.

3.3. Source identification in sediments

The PAH profiles, expressing the relative distribution of PAHcongeners, in the eight tropical Asian countries are given inFig. 4. In rural areas, alkylated PAHs were depleted and parentalPAHs were dominant in all countries (Fig. 4a). These features indi-cate that the rural PAHs are pyrogenic. This pyrogenic nature andthe ubiquitous low concentrations of PAHs across tropical Asiaindicate a background of PAHs of pyrogenic origins. Long rangeatmospheric transport has been reported by many researchers asa source of contamination of PAHs to pristine aquatic environmentin remote areas of cold climatic regions (Halsall et al., 2001; Tsapa-

Fig. 5. Ratios of methylated PAHs to parent PAHs in tropical Asian sediments in com

kis et al., 2003; Prevedouros et al., 2004). Hence a low but signifi-cant distribution of PAHs in rural areas of all tropical Asiancountries could be due to either widespread dispersion of urban-derived pyrogenic PAHs through long-range atmospheric transport(Sporstol et al., 1983), or the ubiquity of forest fires (Stout et al.,2001; Kim et al., 2003; Krauss et al., 2005), followed by woodand coal combustion for cooking and other combustion productscomes from local activities. Relatively higher abundance of high-er-molecular weight species in rural sediments from India andIndonesia (Fig. 4a) might suggest, the higher contribution fromcoal combustion used in cooking, as they were privileged in cook-ing soot from coke oven (Fig. 6). On the other hand, urban sedi-ments had a striking compositional feature (Fig. 4b): alkyl PAHsand lower-molecular-weight PAHs were more abundant in all trop-ical Asian cities (except in India) than in Tokyo and in other indus-trialized countries. This indicates a greater input of petrogenicPAHs to tropical urban waters.

To discuss the source of PAHs more quantitatively, we calcu-lated MP/P, MC/C, MPy/Py, and MPAHs/PAHs. Fig. 5a shows thatMP/P > 0.4 in most samples in all countries, signifying that mostlocations in all countries, including India and Japan, are affectedby petrogenic inputs. This is consistent with the fact that PAHs inpetrogenic sources such as crude oil are abundant in lower-molec-ular-weight species, including the phenanthrene series (Fig. 6). Incontrast, MC/C < 1.0 in most samples in all countries, showing apyrogenic signature (Fig. 5c). This is probably because pyrogenicPAHs are relatively rich in higher-molecular-weight species,whereas petrogenic PAHs are depleted in them, such as chryseneseries (Fig. 6). In comparison to these two extreme cases, the pyr-ene–fluoranthene series exhibited intermediate and interestingfeatures (Fig. 5b): Indian and Japanese sediments are exclusivelypyrogenic (MPy/Py� 0.5), whereas Malaysian and Indonesian sed-iments are extremely petrogenic (MPy/Py� 0.5). Thai sedimentsare a mixture of petrogenic and pyrogenic, whereas Philippineand Cambodian sediments are mainly petrogenic, and Laotianand Vietnamese sediments are mainly pyrogenic. Overall, Indianand Japanese sediments are strongly pyrogenic (MPAHs/PAHs� 0.8), Laotian sediments are pyrogenic, Thai and

parison to those in Tokyo, Japan. Cross: urban locations; square: rural locations.

Fig. 7. Ratio of C30 hopane to total PAHs in tropical Asian sediments in comparisonto those in Tokyo, Japan. Cross: urban locations; square: rural locations.

M. Saha et al. / Marine Pollution Bulletin 58 (2009) 189–200 197

Vietnamese sediments are mixed petrogenic and pyrogenic, Indo-nesian and Malaysian sediments are strongly petrogenic (MPAHs/PAHs > 0.8), and Cambodian and Philippine sediments are mostlypetrogenic (Fig. 5d). Our data clearly demonstrate that the contri-butions of petrogenic and pyrogenic sources are uneven among thehomologs, reflecting their relative abundance in the sources. Ingeneral, the phenanthrene series had a greater petrogenic contri-bution, and the chrysene series had a greater pyrogenic contribu-tion. Furthermore, petrogenic contributions to specific PAHhomologs varied among countries owing to the different intensi-ties of petrogenic inputs among the countries. Countries with high-er petrogenic inputs, such as Malaysia and Indonesia, had apetrogenic signature even for the chrysene series. On the otherhand, countries with higher pyrogenic inputs, such as India and To-kyo, Japan, had a petrogenic signature only in the phenanthreneseries. The reason for the difference is the differential homolog dis-tributions among petrogenic and pyrogenic sources. Overall, theseresults illustrate the ubiquitous input of PAHs with a petrogenicsignature in sediments of all the tropical Asian countries except In-dia. The strong pyrogenic signature of the Indian sediments is an-other interesting finding of this study.

We also examined the other ratios, i.e., Pyr/Fluo, Anth/(An-th + Phe), BaA/(BaA + Chry), IP/(IP + BghiP), for source identification(Table S2). They corroborate the petrogenic nature of sediments inall countries (except India). But there are some exceptions. Forexample, although in most of the samples having Pyr/Fluo > 1shows petrogenic signature of alkylated PAHs, there are some sam-ples (e.g., TS1 and PPC3 from Cambodia,) which have Pyr/Fluo < 1show petrogenic signature with the alkylated PAHs. Similarly,some samples from Cambodia, Indonesia, Malaysia, the Philip-pines, Vietnam, Thailand, and Tokyo, Japan having Anth/(An-th + Phe) > 0.1 and BaA/(BaA + Chry) > 0.35 (i.e., a pyrogenic

Fig. 6. PAH profiles in pote

signature) have petrogenic characteristics by alkyl PAH ratios.These discrepancies are probably due to inconsistencies associatedwith the conventional ratios, as mentioned above.

In most of the industrialized countries a pyrogenic input ofPAHs in aquatic sediments was reported (Hites et al., 1980; Wake-ham, 1996; Zeng and Vista, 1997; Pereira et al., 1999; Woodheadet al., 1999; Notar et al., 2001). A recent widescale study of back-ground anthropogenic hydrocarbons in surficial sediments col-lected from major cities throughout the USA using many ratios toidentify the sources of PAHs affirmed the pyrogenic origin of urbanbackground PAHs (Stout et al., 2004). In comparison to the indus-trialized countries, our finding of widespread inputs of petrogenicPAHs to tropical Asian cities (except in India) is unique.

ntial source materials.

Fig. 8. Sedimentary hopane profiles for urban locations in tropical Asian countries in comparison to that in Tokyo, Japan.

198 M. Saha et al. / Marine Pollution Bulletin 58 (2009) 189–200

The ubiquitous inputs of petrogenic PAHs in all tropical Asiancountries is supported by the ratio of hopanes to PAHs. Usually aratio of C30 hopane/total PAHs > 0.25 indicates the dominance ofpetrogenic input (Boonyatumanond et al., 2007) (Fig. S2). Fig. 7shows that C30 hopane/total PAHs > 0.25 in the tropical Asian sed-iments except in India and Tokyo, Japan, confirming the greater in-put of petrogenic PAHs in the tropical Asian cities. Hopanes consistof several homologs and isomers, and their compositions varyamong crude oils depending on their sources and maturationstages; therefore, the compositions have been used to distinguishthe sources of petroleum pollution. The hopane profiles in the ur-ban sediments (Fig. 8) were uniform across all countries and arecharacterized by the predominance of 17a,21b(H)-C30 hopane

(C3017a) and 17a,21b(H)-C29 hopane (C2917a) and a step progres-sion of C31–C35 homohopanes. This unique uniformity in hopaneprofile among all countries indicates the wide distribution of a sin-gle source of hopanes. The hopane profiles were similar to thosefound in automobile-related sources (i.e., used engine oil, automo-bile exhaust from gasoline- and diesel-powered cars, asphalt, andtire debris; Fig. S3). All these data indicate that automobile-relatedsources could be major sources of petrogenic PAHs in the tropicalAsian cities. Identification of specific sources of the petrogenicPAHs in each country will be an important task.

The results from India contrast with those of the other tropicalAsian countries. PAHs in Indian sediments showed severe deple-tion of alkylated species with extremely low MP/P (0.47 ± 0.24),

M. Saha et al. / Marine Pollution Bulletin 58 (2009) 189–200 199

MC/C (0.23 ± 0.07), and MPy/Py (0.13 ± 0.06) and lower C30 ho-panes/total PAHs (0.09 ± 0.05). This result demonstrates that PAHsincorporated into Indian waters have an exclusive pyrogenic signa-ture. The difference might be due to differences in energy sources.We found that most industries in India use coal, coal products andwood as sources of energy (almost 74% of total energy consump-tion), and use very little crude oil and petroleum (17% of total en-ergy consumption). In contrast, crude oil and petroleum productsare the main fossil fuels used in the other countries (the Philip-pines, 41%; Malaysia, 49%; Indonesia, 35%; Thailand, 54% of totalenergy consumption; data from World Resources Institute). Conse-quently, the coal, charcoal, and wood burned in India explain thepyrogenic signature of the PAHs in sediment. Here with the fartherdetailed identification of source of pyrogenic PAHs (i.e., coal vs.wood) based on collection and analysis of various source materialsin India and utilization of molecular markers will be an interestingeffort for our future research.

Acknowledgements

This study was financially supported by a Grant-in-Aid (ProjectNos. 15405044, 19404001). Several students at our laboratoriesprovided welcome assistance with the field work.

Appendix A. Supplementary material

Supplementary data associated with this article can be found, inthe online version, at doi:10.1016/j.marpolbul.2008.04.049.

References

Bence, A.E., Kvenvolden, K.A., Kennicutt II, M.C., 1996. Organic geochemistry appliedto environmental assessments of Prince William Sound, Alaska, after the ExxonValdez oil spill – a review. Organic Geochemistry 24, 7–42.

Benner, B.A., Wise, S.A., Currie, L.A., Klouda, G.A., Klinedinst, D.B., Zweidinger, R.B.,Stevens, R.K., Lewis, C.W., 1995. Distinguishing the contributions of residentialwood combustion and mobile source emissions using relative concentrations ofdimethylphenanthrene isomers. Environmental Science and Technology 29,2382–2389.

Bixian, M., Jiamo, F., Gan, Z., Zheng, L., Yushun, M., Guoying, S., Xingmin, W., 2001.Polycyclic aromatic hydrocarbons in sediments from the Pearl river and estuary,China: spatial and temporal distribution and sources. Applied Geochemistry 16,1429–1445.

Blumer, M., 1976. Polycyclic aromatic compounds in nature. Scientific American234, 34–45.

Boehm, P.D., Page, D.S., Gilfillan, E.S., Bence, A.E., Burns, W.A., Mankiewicz, P.J., 1998.Study of the fates and effects of the exxon valdez oil spill on benthic sedimentsin two bays in Prince William Sound, Alaska. 1. Study design, chemistry, andsource fingerprinting. Environmental Science and Technology 32, 567–576.

Boonyatumanond, R., Murakami, M., Wattayakorn, G., Togo, A., Takada, H., 2007.Sources of polycyclic aromatic hydrocarbons (PAHs) in street dust in a tropicalAsian mega-city, Bangkok, Thailand. The Science of the Total Environment 384,420–432.

Boonyatumanond, R., Wattayakorn, G., Togo, A., Takada, H., 2006. Distribution andorigins of polycyclic aromatic hydrocarbons (PAHs) in riverine, estuarine andmarine sediments in Thailand. Marine Pollution Bulletin 52, 942–956.

Budzinski, H., Jones, I., Bellocq, J., Pierard, C., Garrigues, P., 1997. Evaluation ofsediment contamination by polycyclic aromatic hydrocarbons in the GirondeEstuary. Marine Chemistry 58, 85–97.

Eganhouse, R.P., Gossett, R.W., 1991. Historical deposition and biogeochemical fateof polycyclic aromatic hydrocarbons in sediments near a major submarinewastewater outfall in Southern California. In: Baker, R.A. (Ed.), OrganicSubstances and Sediments in Water: Processes and Analytical, vol. 2. LewisPublishers, Boca Raton, FL, pp. 191–220.

Farrington, J.W., Goldberg, E.D., Risebrough, R.W., Martin, J.H., Bowen, V.T., 1983. US‘‘Mussel Watch” 1976–1978: an overview of the trace-metal, DDE, PCB,hydrocarbons, and artificial radionuclide data. Environmental Science andTechnology 17, 490–496.

Faure, P., Landais, P., Schlepp, L., Michels, R., 2000. Evidence for diffusecontamination of river sediments by road asphalt particles. EnvironmentalScience and Technology 34, 1174–1181.

Garrigues, P., Budzinski, H., Manitz, M.P., Wise, S.A., 1995. Pyrolytic and petorgenicinputs in recent sediments: a definitive signature through phenanthrene andchrysene compounds distribution. Polycyclic Aromatic Compounds 7, 275–284.

Guo, Z., Lin, T., Zhang, G., Yang, Z., Fang, M., 2006. High-resolution depositionalrecords of polycyclic aromatic hydrocarbons in the central continental shelfmud of the East China Sea. Environmental Science and Technology 40, 5304–5311.

Gustafsson, O., Haghseta, F., Chan, C., Macfarlane, J., Gschwend, P.M., 1997.Quantification of the dilute sedimentary soot phase: implications for PAHspeciation and bioavailability. Environmental Science and Technology 31, 203–209.

Halsall, C.J., Sweetman, A.J., Barrie, L.A., Jones, K.C., 2001. Modelling the behaviour ofPAHs during atmospheric transport from the UK to the Arctic. AtmosphericEnvironment 35, 255–267.

Hites, R.A., Laflamme, R.F., JR, J.G.W., Farrington, J.W., Deuser, W.G., 1980. Polycyclicaromatic hydrocarbons in an anoxic sediment core from the PettaquamscuttRiver (Rhode Island, USA). Geochimica et Cosmochimica Acta 44, 873–878.

Kim, E.-J., Oh, J.-E., Chang, Y.-S., 2003. Effects of forest fire on the level anddistribution of PCDD/Fs and PAHs in soil. The Science of the Total Environment311, 177–189.

Krauss, M., Wilcke, W., Martius, C., Bandeira, A.G., Garcia, M.V.B., Amelung, W.,2005. Atmospheric versus biological sources of polycyclic aromatichydrocarbons (PAHs) in a tropical rain forest environment. EnvironmentalPollution 135, 143–154.

Kvenvolden, K.A., Hostettler, F.D., Carlson, P.R., Bapp, J.B., Threlkeld, C.N., Warden,A., 1995. Ubiquitous tar talls with a california-source signature on theshorelines of Prince William Sounds, Alaska. Environmental Science andTechnology 29, 2684–2694.

Lee, M.L., Prado, G.P., Howard, J.B., Hites, R.A., 1977. Source identification of urbanairborne polycyclic aromatic hydrocarbons by gas chromatographic massspectrometry and high resolution mass spectrometry. Biomedical MassSpectrometry 4, 182–186.

Lee, M.L., Vassllaros, D.L., White, C.M., Novotny, M., 1979. Retention indices forprogrammed-temperature capillary-column gas chromatography of polycyclicaromatic hydrocarbons. Analytical Chemistry 51, 768–773.

Lipiatou, E., Saliot, A., 1991. Hydrocarbon contamination of the Rhone Delta andWestern Mediterranean. Marine Pollution Bulletin 22, 297–304.

Luellen, D.R., Shea, D., 2003. Semipermeable membrane devices accumulateconserved ratios of sterane and hopane petroleum biomarkers. Chemosphere53, 705–713.

McCready, S., Slee, D.J., Birch, G.F., Taylor, S.E., 2000. The distribution of polycyclicaromatic hydrocarbons in surficial sediments of Sydney Harbour, Australia.Marine Pollution Bulletin 40, 999–1006.

McGroddy, S.E., Farrington, J.W., 1995. Sediment porewater partitioning ofpolycyclic aromatic hydrocarbons in three cores from Boston Harbor,Massachusetts. Environmental Science and Technology 29, 1542–1550.

Notar, M., Leskovsek, H., Faganeli, J., 2001. Composition, distribution and sources ofpolycyclic aromatic hydrocarbons in sediments of the Gulf of Trieste, northernAdriatic Sea. Marine Pollution Bulletin 42, 36–44.

Pereira, W.E., Hostettler, F.D., Luoma, S.N., Van Geen, A., Fuller, C.C., Anima, R.J.,1999. Sedimentary record of anthropogenic and biogenic polycyclicaromatic hydrocarbons in San Francisco Bay, California. Marine Chemistry64, 99–113.

Peters, K.E., Walters, C.C., Moldowan, J.M., 2005. The Biomarker Guide, second ed..Biomarkers and Isotopes in the Environment and Human History, vol. 1Cambridge University Press, NJ. 471 pp.

Prevedouros, K., Jones, K.C., Sweetman, A.J., 2004. Modelling the atmospheric fateand seasonality of polycyclic aromatic hydrocarbons in the UK. Chemosphere56, 195–208.

Prince, R.C., Elmendorf, D.L., Lute, J.R., Hsu, C.S., Halth, C.E., Senlus, J.D., Dechert, G.J.,Douglas, G.S., Butler, E.L., 1994. 17a(H),21a(H)-Hopane as a conservativeinternal marker for estimating the biodegradation of cruce oil. EnvironmentalScience and Technology 28, 142–145.

Ramdahl, T., 1983. Retene-a molecular marker of wood combustion in ambient air.Nature 306, 580–582.

Rogge, W.F., Hildemann, L.M., Mazurek, M.A., Cass, G.R., Simoneit, B.R.T., 1993.Sources of fine organic aerosol. 2. Noncatalyst and catalyst-equippedautomobiles and heavy-duty trucks. Environmental Science and Technology27, 636–651.

Simcik, M.F., Eisenreich, S.J., Golden, K.A., Liu, S.P., Lipiatou, E., Swackhamer, D.L.,Long, D.T., 1996. Atmospheric loading of polycyclic aromatic hydrocarbons toLake Michigan as recorded in the sediments. Environmental Science andTechnology 30, 3039–3046.

Sporstol, S., Gjos, N., Lichtenthaler, R.G., Gustavsen, K.O., Urdal, K., Oreld, F., Skei, J.,1983. Source identification of aromatic hydrocarbons in sediments using GC/MS. Environmental Science and Technology 17, 282–286.

Stout, S.A., Magar, V.S., Uhler, R.M., Ickes, J., Abbott, J., Brenner, R., 2001.Characterization of Naturally-occurring and anthropogenic PAHs in urbansediments-Wycoff/Eagle Harbor Superfund Site. Environmental Forensics 2,287–300.

Stout, S.A., Uhler, A.D., Emsbo-Mattingly, S.D., 2004. Comparative evaluation ofbackground anthropogenic hydrocarbons in surficial sediments from nineurban waterways. Environmental Science and Technology 38, 2987–2994.

Takada, H., Onda, T., Ogura, N., 1990. Determination of polycyclic aromatichydrocarbons in urban street dusts and their source materials by capillary gaschromatography. Environmental Science and Technology 24, 1179–1186.

Tsapakis, M., Stephanou, E.G., Karakassis, I., 2003. Evaluation of atmospherictransport as a nonpoint source of polycyclic aromatic hydrocarbons in marinesediments of the Eastern Mediterranean. Marine Chemistry 80, 283–298.

200 M. Saha et al. / Marine Pollution Bulletin 58 (2009) 189–200

Volkman, J.K., Revill, A.T., Murray, A.P., 1997. Applications of biomarkers foridentifying sources of natural and pollutant hydrocarbons in aquaticenvironments. In: Eganhouse, R.P. (Ed.), Molecular Markers in EnvironmentalGeochemistry. American Chemical Society, Washington, DC, pp. 83–99.

Wakeham, S., 1996. Aliphatic and polycyclic aromatic hydrocarbons in Black Seasediments. Marine Chemistry 53, 187–205.

Wang, Z., Fingas, M., Sergy, G., 1994. Study of 22-year-old arrow oil samples usingbiomarker compounds by GC/MS. Environmental Science and Technology 28,1733–1746.

Wang, Z., Fingas, M., Shu, Y.Y., Sigouin, L., Landriault, M., Lambert, P., Turpin, R.,Campagna, P., Mullin, J., 1999. Quantitative characterization of PAHs in burnresidue and soot samples and differentiation of pyrogenic PAHs from petrogenicPAHs-the 1994 mobile burn study. Environmental Science and Technology 33,3100–3109.

Woodhead, R.J., Law, R.J., Matthiessen, P., 1999. Polycyclic aromatic hydrocarbons insurface sediments around England and Wales, and their possible biologicalsignificance. Marine Pollution Bulletin 38, 773–790.

World Resources Institute. Earth Trends Environmental Information, Washington,DC. <http://earthtrends.wri.org/country_profiles/index.php?theme=6>.

Youngblood, W.W., Blumer, M., 1975. Polycyclic aromatic hydrocarbons in theenvironment: homologous series in soils and recent marine sediments.Geochimica et Cosmochimica Acta 39, 1303–1314.

Yunker, M.B., Macdonald, R.W., Vingarzan, R., Mitchell, R.H., Goyette, D.S.,Stephanie, 2002. PAHs in the Fraser River basin: a critical appraisal of PAHratios as indicators of PAH source and composition. Organic Geochemistry 33,489–515.

Zakaria, M.P., Okuda, T., Takada, H., 2001. Polycyclic aromatic hydrocarbon (PAHs)and hopanes in stranded tar-balls on the coasts of Peninsular Malaysia:applications of biomarkers for identifying sources of oil pollution. MarinePollution Bulletin 42, 1357–1366.

Zakaria, M.P., Takada, H., Tsutsumi, S., Ohno, K., Yamada, J., Kouno, E., Kumata, H.,2002. Distribution of polycyclic aromatic hydrocarbons (PAHs) in rivers andestuaries in Malaysia: a widespread input of petrogenic PAHs. EnvironmentalScience and Technology 36, 1907–1918.

Zeng, E.Y., Vista, C.L., 1997. Organic Pollutants In the coastal environment off SanDiego, California.1. Source identification and assessment by compositionalindices of polycyclic aromatic hydrocarbons. Environmental Toxicology andChemistry 16, 179–188.