Identi®cation of speci®c organic contaminants for
estimating the contribution of the Elbe river to
the pollution of the German Bight
J. Schwarzbauer
a,*, R. Littke
a, V. Weigelt
baInstitute of Geology and Geochemistry of Petroleum and Coal, Aachen University of Technology, Lochnerstr. 4-20,
D-52056 Aachen, Germany
bFederal Maritime and Hydrographic Agency, Bernhard Nocht Str. 78, D-20359 Hamburg, Germany
Abstract
GC/MS analyses have been applied to sediment samples of the German Bight in order to document the state of organic contamination as well as to identify speci®c molecular markers that are appropriate to estimate the discharge of anthropogenic compounds derived from the Elbe river. Detailed screening analyses revealed a wide variety of organic lipophilic compounds of biogenic, petrogenic as well as anthropogenic origin. Potential marker compounds indicating the contribution of the Elbe river could be attributed mainly to the chlorinated aromatic contaminants. Speci®cally, these include to hexachlorobenzenes, mono- to dichloronaphthalenes, hexachlorobutadiene, tetra-butyl tin, alkylsulfonic acid phenylesters, 1,2,3,6,7,8-hexahydro-1,1,6,6-tetramethyl-4-isopropyl-as-indacene and 4,40 -dichlorodiphenylsul®de. These compounds are suitable to indicate the spatial distribution of Elbe river derived organic matter.#2000 Elsevier Science Ltd. All rights reserved.
1. Introduction
The marine environment of the North Sea is highly in¯uenced by anthropogenic input as a result of intense navigation, petroleum and gas production, atmospheric deposition as well as riverine contribution of terrestrial pollutants. The qualitative and quantitative composi-tion of the organic material in the sediment and the water column re¯ects the discharge of anthropogenic contaminants. Hence, natural biogenic substances are accompanied by a wide variety of anthropogenic com-pounds.
In the German Bight a signi®cant proportion of the anthropogenic organic matter is contributed by con-taminated riverine systems discharging into the North Sea. Next to the Ems and Weser rivers, the Elbe river is the most polluted riverine system due to well known
industrial emissions and partly de®cient sewage treat-ment in the catchtreat-ment area. In order to estimate the ¯uvial input to the organic contamination of marine sediments, analyses of carbon ¯uxes by bulk parameter such as dissolved organic carbon (DOC), particulate organic matter (POM), terrestrial organic matter (TOM) are useful (Ittekkot, 1988; Gupta et al., 1997; Keil et al., 1997; Alberts and TakaÂcs, 1999). More detailed information about the terrestrial contribution to the marine organic matter could be obtained by identi®cation and quanti®cation of several speci®c molecular markers (Hedges et al., 1997). For example, analyses of carbohydrates, amino carbohydrates and amino acids in the suspended particulate matter of the river Indus indicated a signi®cant terrigenous input to the marine environment (Ittekkot and Arain, 1986). Hedges and Parker (1976) characterized the terrestrial organic matter in surface sediments from the Gulf of Mexico using lignin oxidation products as markers. The contribution of the Mackenzie river to the Beaufort sea coastal sediments was assessed by examination of spe-ci®c aliphatic and aromatic hydrocarbons (Yunker et al., 1991, 1993). With a similar aim, Zegouagh et al.
0146-6380/00/$ - see front matter#2000 Elsevier Science Ltd. All rights reserved.
www.elsevier.nl/locate/orggeochem
* Corresponding author. Tel.: 241-805750; fax: +49-241-8888152.
(1996, 1998) studied the molecular and isotopic proper-ties both of hydrocarbons and acids in sediments of the Lena River delta and the Laptev Sea.
Information about the ¯uvial discharge into the mar-ine environment can also be achieved with anthro-pogenic substances (Eganhouse, 1997; Takada et al., 1997). Well known anthropogenic markers include e.g. tetrapropylene-based alkylbenzenes (TAB), linear alkyl-benzenes (LAB) and the sulfonated analogues (linear alkylbenzenesulfonates, LAS). The LAS are widely used surfactants and the LAB are synthetic raw material. Their occurrence in the aquatic environment re¯ects the emission of municipal waste water euents (Takada and Eganhouse, 1998, and references cited therein). Fecal steroids derived from sewage contaminated rivers have also been used to document the discharge of ¯uvial anthropogenic matter to coastal sediments (Takada and Eganhouse, 1998, and references cited therein).
Natural and anthropogenic marker compounds are useful to distinguish between marine and terrigenous organic matter in coastal sediments and water. But in order to point out the contributions made by dierent estuaries situated close together, such as in the area of the German Bight, more speci®c molecular marker information is needed. The emission of speci®c anthro-pogenic compounds from point sources or the common usage of characteristic technical formulations results in quite dierent patterns of organic substances. These can be used as river-speci®c molecular markers.
Detailed analyses of the organic matter are necessary to identify such speci®c marker compounds, but only a few investigations have been carried out on organic contaminants in coastal water and sediments of the North Sea. Previous detailed analyses of lipophilic and low molecular compounds in Elbe river water have indicated a high abundance of river-speci®c organic substances (Franke et al., 1995; Theobald et al., 1995). For preselected compounds (e.g. thiophosphates, ben-zothiazoles, nitrobenzenes and polycyclic musk fra-grances) the contribution of the Elbe river to the contamination of coastal waters has been demonstrated quantitatively (Gatermann et al., 1995, 1996; Bester et al., 1997, 1998).
In order to document the state of organic pollution in the sediments, GC/MS screening analysis has been applied to samples from the German Bight. Based on full scan electron impact mass spectra, gas chromato-graphic retention times and synthetic reference com-pounds, several classes of biogenic and anthropogenic compounds were identi®ed. The main focus of our study was to isolate Elbe-speci®c molecular markers that are appropriate to estimate the discharge of riverine anthropogenic compounds to the sediments of the Ger-man Bight. These compounds can only be potential markers because little information is available about the organic matter of the Ems and Weser rivers, which are
situated close to the Elbe and also in¯uence the sedi-ments of the German Bight.
2. Experimental
2.1. Samples
Sediment samples (Table 1) were taken in 1998 by the German Federal Maritime and Hydrographic Agency (Hamburg) using a van Veen grab. This yielded material from the sediment surface to a depth of approximately 15 cm. All sampling locations are shown in Fig. 1. The wet sediments were stored in glass ¯asks with Te¯on lined screw caps at 4C in the dark.
Because of the intense analytical approach (Fig. 2) only the samples of these seven locations were investi-gated. Three of the samples seemed to be directly in¯u-enced by the Elbe river (A,B) and the Weser and Ems rivers (G), whereas the contributions of the riverine sys-tems to the organic matter of the sediments situated farer from the coastal area (C,D,E,F) are still ambiguous.
2.2. Extraction
Amounts of 200±400 g fresh wet sediments were extracted sequentially with 50 ml of acetone, twice with 50 mln-hexane/acetone 50/50 (vol/vol) and twice with 50 mln-hexane. Extraction was carried out by disper-sing the samples in portions of 20 g for 5 min in the solvent using a high-speed dispersion tool (Ultra-Turrax T25, IKA, Stauen, FRG). Each extraction step was followed by centrifugation at 4000 rpm and separation of the solvent. After combining the extracts and separ-ating the aqueous phase, the organic layer was dried with anhydrous granulated sodium sulphate and con-centrated to a volume of 1 ml. Sulfur was removed by addition of 50 mg of activated copper powder and ultrasonic agitation. After 16 h, the extract was pre-pared for chromatographic fractionation by ®ltration over 1 g of anhydrous granulated sodium sulphate and concentration to 0.5 ml.
Table 1
Sediment samples collected from the German Bight (see Fig. 1 for locations)
Sample Altitude Latitude Fraction of grain size < 63 mm
2.3. Fractionation
Sediment extracts were separated into six fractions by column chromatography (Baker, silica gel 40mm) using mixtures of n-pentane and dichloromethane as the elu-ent according to Franke et al. (1995). Fraction 1: n -pentane (5 ml), fraction 2: n-pentane/dichloromethane 95/5 v/v (8.5 ml), fraction 3:n-pentane/dichloromethane 90/10 v/v (5 ml), fraction 4:n-pentane/dichloromethane 40/60 v/v (5 ml), fraction 5: dichloromethane (5 ml), fraction 6: methanol (5 ml). The acidic compounds of fraction 6 were methylated by addition of 0.5 ml of a methanolic diazomethane solution. Prior to analysis, 50 ml of an internal standard solution containing 6.0 ng/ml d36-hexadecane, 5.1 ng/mld10-anthracene and 4.7 ng/ml
d12-chrysene in n-hexane were added to each fraction,
and the volume was reduced to approximately 50ml by rotary evaporation at room temperature. All fractions were analysed on a gas chromatograph equipped with ¯ame ionization and electron capture detector (GC-FID/ECD) and on a gas chromatograph linked to a mass spectrometer (GC±MS).
Dry weights of sediments were determined by drying separate aliquots of samples at 110C to constant weight.
2.4. Gas chromatographic analysis
Gas chromatographic analysis was carried out on a GC8000 gas chromatograph (Fisons instruments,
Wies-0.25 mm ®lm SE54 fused silica capillary column (CS Chromatographie Service, Langerwehe, FRG). The end of the capillary column was split to lead the eluate separately to a ¯ame ionization detector (FID) and an electron capture detector (ECD) for a simultaneous detection of the analytes. Chromatographic conditions were: 1ml split/splitless injection at 60C, splitless time 60 s, 3 min hold, then programmed at 3/min to 300C, hydrogen carrier gas velocity was 25 cm/s.
2.5. GC/MS-analysis
GC/MS analyses were performed on a Finnigan MAT 8222 mass spectrometer (Finnigan, Bremen, FRG) linked to a Varian Series 3700 gas chromato-graph (Varian, Walnut Creek, USA) which was equip-ped with a 30 m0.25 mm i.d.0.25mm ®lm BPX5 fused silica capillary column (SGE, Weiterstadt, FRG). Chromatographic conditions were: 1 ml split/splitless injection at 60C, splitless time 60 s, 3 min hold, then programmed at 3C/min to 300C, helium carrier gas velocity was 40 cm/s.
For low resolution mass spectra the mass spectro-meter was operated at a resolution of 1000 in electron impact ionization mode (EI+, 70 eV) with a source
temperature of 200C with scanning from 35 to 700 amu at a rate of 1 s/decade with an inter-scan time of 0.1 s.
Identi®cation of individual compounds was based on comparison of EI+-mass spectra with those of reference
Mass Spectral Library NIST98, Wiley/NBS Registry of Mass Spectral Data, 4th Ed., electronic versions) and gas chromatographic retention times, elution patterns or retention indices (e.g. Vassilaros et al., 1982; Rostad and Pereira, 1986; Ballschmitter et al.; 1987, Bundt et al., 1991; Paschke et al., 1992; Peters and Moldowan, 1993; Wang et al., 1994). For correction of injection time inaccuracies the retention times of the internal standard compounds were used.
3. Results and discussion
The non-target screening analyses revealed a large number of individual organic compounds occurring in sediments of the German Bight. All identi®ed con-taminants are listed in Table 2. These are subdivided and arranged either by their structural properties or technical applications in case of some anthropogenic substances.
Table 2
Organic compounds identi®ed in sediments of the German Bight
Compounds A B C D E F G
Alkanes, cycloalkanes and alkenes
Homologous series ofn-alkanes (C9to C30)a + + + + + + +
2,2,4,4,6,8,8-Heptamethylnonanea + + + + + + +
Homologous series ofn-alkylcyclohexanes + (+)g (+) + + + (+)
(C4- to C20side chain)c
Homologous series ofn-alkenes (C12to C20)a +
Terpenoids and degradation products
Limonenea + + + + + + +
Dihydroactinidiolidec + + + + + +
a-Iononec + + + + + +
b-Iononec + + + + + +
b-Cyclocitrala + + +
Cadalenec +
Calamenenec + + + + + + +
a-Cedrenec +
Longicyclenec + +
Junipenec + +
7-Isopropyl-1-methylphenanthrenee + + + + + + +
1,2,3,4-Tetrahydro-7-isopropyl-1-methylphenanthrenee + + + + + + +
Dehydroabietine +
Dehydroabietanee +
2,6-Dimethylundecanee + + + + + + +
Pristanea + + + + + + +
Phytanea + + + + + + +
Phytene (1 isomer)d + + + + + +
Phytadienes (3 isomers)d + + + + + +
6,10-Dimethylundecan-2-onee + + + + + + +
6,10-Dimethyl-5,9-undecadien-2-onee + + + + + + +
6,10,14-Trimethylpentadecan-2-onee + + + + + + +
Phytola
Phytolic acide + + + + +
4,8,12-Trimethyltridecanoic acide + + + + + +
4,8,12-Trimethyltetradecanoic acidc + + + + +
Squalenea + + + + + + +
Hopanoids
18a(H)-Trisnorneohopane,Tsc + + + + + + +
17a(H)-Trisnorhopane,Tmc + + + + + + +
18a-Norneohopanec + + + + + +
17a(H),21b(H)-Norhopanec + + + + + + +
17b(H),21a(H)-Norhopanec + + + + + + +
17b(H),21b(H)-Norhopanec + + + + + + +
17a(H),21b(H)-Hopanec + + + + + + +
17b(H),21b(H)-Hopanec + + + + + + +
(22S)-17a(H),21b(H)-Homohopanec + + + + + + +
(22R)-17a(H),21b(H)-Homohopanec + + + + + + +
(22S)-17a(H),21b(H)-Bishomohopanec + + + + + + +
(22R)-17a(H),21b(H)-Bishomohopanec + + + + + + +
(22S)-17a(H),21b(H)-Trishomohopanec + + + + + + +
(22R)-17a(H),21b(H)-Trishomohopaned + + + + + + +
Steranes and steroids
C20-5a(H),14a(H),14a(H)-Steranec + + + + + + +
C21-5a(H),14b(H),17b(H)-Steranec + + + + + + +
Table 2 (continued)
Compounds A B C D E F G
C27-20S-13b(H),17a(H)-Diasteranec + + + + + + +
C27-20R-13b(H),17a(H)-Diasteranec + + + + + + +
C27-20S-13a(H),17b(H)-Diasteranec + + + + + + +
C27-20R-13a(H),17b(H)-Diasteranec + + + + + + +
C28-20S-13b(H),17a(H)-Diasteranec + + + + + + +
C29-20S-13b(H),17a(H)-Diasteranec + + + + + + +
20S-5a(H),14a(H),17a(H)-Cholestanec + + + + + + +
20R-5a(H),14b(H),17b(H)-Cholestanec + + + + + + +
20S-5a(H),14b(H),17b(H)-Cholestanec + + + + + + +
20R-5a(H),14a(H),17a(H)-Cholestanec + + + + + + +
Cholestenes (1 isomer)d + + + + + + +
Cholestadienes (3 isomers)d (+) (+) + (+) + + +
Cholestatrienes (3 isomers)d + + + + + + +
5a(H)-Cholestan-3-onea + + + + + +
5b(H)-Cholestan-3-onea + + + + + +
20S-5a(H),14a(H),17a(H)-Ergostanec + + + + + + +
20R-5a(H),14b(H),17b(H)-Ergostanec + + + + + + +
20S-5a(H),14b(H),17b(H)-Ergostanec + + + + + + +
20R-5a(H),14a(H),17a(H)-Ergostanec + + + + + + +
Ergostanones (2 isomers)d + + +
20S-5a(H), 14a(H),17a(H)-Stigmastanec + + + + + + +
20R-5a (H),14b(H),17b(H)-Stigmastanec + + + + + + +
20S-5a(H),14b(H),17b(H)-Stigmastanec + + + + + + +
20R-5a(H),14a(H),17a(H)-Stigmastanec + + + + + + +
Stigmastened + + + + + + +
Stigmastadienes (1 isomer)d + + + + + + +
Stigmastatrienes (2 isomers)d + + + + + + +
Stigmastanones (2 isomers)d + + + +
Alkylbenzenes
Ethylbenzenea + + + + + + +
m-/p-Xylenea + + + + + + +
o-Xylenea + + + + + + +
C3-Benzenes (8 isomers)d (+) + + (+) + (+) +
C4-Benzenes (15 isomers)d (+) (+) + + + + +
C5-Benzenes (10 isomers)d (+) + + + + + +
C6-Benzenes (6 isomers)d (+) + (+) (+) + + +
C7-Benzenes (7 isomers)d (+) + (+) + (+) + +
C8-Benzenes (9 isomers)d (+) + (+) (+) (+) + (+)
C9-Benzenes (11 isomers)d (+) + (+) (+) + + (+)
C10-Benzenes (8 isomers)d (+) + (+) (+) + + (+)
C11-Benzenes (3 isomers)d (+) + (+) (+) + + (+)
C12-Benzenes (5 isomers)d (+) + (+) + + + (+)
C13-Benzenes (5 isomers)d (+) + (+) + + + (+)
C14-Benzenes (11 isomers)d (+) + (+) + + (+)
5-Phenyldecanea + + + + + + +
4-Phenyldecanea + + + + + + +
3-Phenyldecanea + +
6-Phenylundecanea + + + + + + +
5-Phenylundecanea + + + + + + +
4-Phenylundecanea + + + + + + +
3-Phenylundecanea + + + + + + +
2-Phenylundecanea + + + + + + +
6-Phenyldodecanea + + + + + + +
5-Phenyldodecanea + + + + + + +
4-Phenyldodecanea + + + + + + +
3-Phenyldodecanea + + + + + + +
Table 2 (continued)
Compounds A B C D E F G
2-Phenyldodecanea + + + + + + +
7-/6-Phenyltridecanea + + + + + + +
5-Phenyltridecanea + + + + + + +
4-Penyltridecanea + + + + + + +
3-Phenyltridecanea + + + + + +
2-Phenyltridecanea + + + + +
Polycyclic aromatic compounds, PACs
Naphthalenea + + + + + + +
Ethylnaphthalene (1 isomer)d + + + + + + +
1-Methylnaphthalenea + + + + + + +
2-Methylnaphthalenea + + + + + + +
C2-Naphthalenes (6 isomers)d + + + + + + +
C3-Naphthalene (10 isomers)d + + + + + + +
C4-Naphthalene (8 isomers)d + + (+) (+) + + (+)
Biphenyla + + + + + + +
3-Methylbiphenylb + + + + + + +
4-Methylbiphenylb + + + + + + +
C2-Biphenyls (3 isomers)d + + + + + + +
C3-Biphenyls (3 isomers)d (+) + + + (+) (+) +
1,1-Diphenylethaneb +
Acenaphtylenea + + + + + + +
Acenaphtenea + + + + + + +
Fluorenea + + + + + + +
9-Methyl¯uorenea + + + + + + +
2-Methyl¯uorenea + + + + + + +
1-Methyl¯uorenea + + + + + + +
Methyl¯uorenes (1 isomer)d + + + + + + +
C2-Fluorenes (6 isomers)d (+) + (+) (+) (+) (+) (+)
1-Phenylnaphthalenea + + + + + + +
2-Phenylnaphthalenea + + + + + + +
Phenanthrenea + + + + + + +
Anthracenea + + + + + + +
3-Methylphenanthreneb + + + + + + +
2-Methylphenanthreneb + + + + + + +
2-Methylanthraceneb + + + + + +
4-/9-Methylphenanthreneb + + + + + + +
1-Methylphenanthreneb + + + + + + +
Dimethylphenanthrene (1 isomer)d + + + + + + +
3,5-Dimethylphenanthreneb + + + + + + +
2,7-Dimethylphenanthreneb + + + + + + +
1,3-3,10-Dimethylphenanthreneb + + + + + + +
1,6-/2,9-Dimethylphenanthreneb + + + + + + +
1,7-Dimethylphenanthreneb + + + + + + +
1,9-/4,9-Dimethylphenanthreneb + + + + + + +
1,8-Dimethylphenanthreneb + + + + + + +
1,2-Dimethylphenanthreneb + + + + + + +
C3-Phenanthrenes/-anthracenes (7 isomers)d + + + + + + +
4H-Cyclopenta(def)phenanthreneb + + + + + + +
Fluoranthenea + + + + + + +
Acephenanthryleneb + + + + + +
Pyrenea + + + + + + +
Methyl¯uoranthenes/-pyrenes (6 isomers)d + + + + + + +
Dimethyl¯uoranthenes/-pyrenes (9 isomers)d + + + + + + +
Ethyl¯uoranthenes/-pyrenes (2 isomers)d +
Table 2 (continued)
Compounds A B C D E F G
m-Terphenylb + + + + +
p-Terphenylb + + + + + + +
Benz(ghi)¯uoranthenea + + + + + + +
Benz(c)phenanthrenea + + + + + + +
Benz(a)anthracenea + + + + + + +
Cyclopenta(cd)pyrenea + +
Chrysene/Triphenylenea + + + + + + +
Naphthaceneb + + + + + + +
Methyl-228 (5 isomers)d,f + + + + + + +
C2-228 (7 isomers)d,f + + + + + + +
1,20-Binaphthylb + + + + + + +
2,20-Binaphthylb + + + + + + +
9-Phenylphenanthreneb + + + + + + +
Phenylphenanthrene/-anthracenes (3 isomers)d + + + + + + +
Benz(x)¯uoranthene (x=j,b,k)a + + + + + + +
Benz(e)pyrenea + + + + + + +
Benz(a)pyrenea + + + + + + +
Perylenea + + + + + + +
Methyl-252 (5 isomers)d,f + + + + + + +
Indeno(1,2,3-cd)pyrenea + + + + + + +
Benzo(ghi)perylenea + + + + + + +
Dibenzo(a,h)anthraceneb + + + + + + +
Dibenzo(a,c)anthraceneb + + + + + + +
Benzo(b)chrysenea + + + + + + +
Piceneb + + + + + + +
Anthanthreneb +
Hydrogenated aromatic compounds
Decalina + + + + + +
Tetralina + + + +
1,1,6-Trimethyletraline + + + + +
3,3,7-Trimethyl-1,2,3,4-tetrahydrochrysenee + + +
Cyclohexylbenzenee + + + + + +
Cyclohexylcyclohexanee + + + +
Sulphur containing PACs
Benzo(b)thiophenea + + + + +
Dibenzothiophenea + + + + +
Benzo(b)naphtho(2,1-d)thiopheneb + + + + + + +
Benzo(b)naphtho(1,2-d)thiopheneb + + + + + + +
Phenanthro(9,10-b)thiopheneb + + + + + + +
Benzo(b)naphtho(2,3-d)thiopheneb + + + + + + +
Methylbenzonaphthothiophenes (4 isomers)d + + + + + + +
Oxygen containing PACs
Benzofurana + + + + + + +
Methylbenzofuran (2 Isomers)d + + + + + + +
Dibenzofurana + + + + +
Methyldibenzofuran (2 isomers)d + + + + + +
C2-Dibenzofuran (4 isomers)d + + + + + + +
Benzonaphthofuran (6 isomers)d + + + (+) + + +
Methylbenzonaphthofuran (4 isomers)d + + + + +
Nitrogen containing PACs
Carbazola + + + + + + +
Methylcarbazoles (2 isomers)d + + + + + + +
Benzcarbazoles (2 isomers)d + + + + (+) +
Table 2 (continued)
Compounds A B C D E F G
Oxygenated aromatic compounds
Cyclpenta(def)phenanthren-4-oneb + + +
9,10-Anthraquinonea + +
Benzanthronea + + + + +
Sul®des
Di-iso-propyldisul®dea + + + + + + +
Di-iso-propyltrisul®dee + + + + + +
Alcohols and phenols
2,9-Dihydroxy-6-methyl-4,7-dioxadecanee + + + + + + +
Phenola + + + + +
4-Cresola + + +
2-/3-Cresola + + +
Aldehydes and ketones
Homologous series ofn-aldehydes (C9to C32)a + + + +
Homologous series of 2-alkanones (C23to C29)b + + (+) (+)
Benzaldehydea + + + + +
Methylacetophenoned + + + + + + +
1-(2,3-Dihydro-1,1-dimethyl-1H-inden-4-yl)-ethanonee + + + +
Alkanoic acids
Homologous series ofn-alkanoic acids (C9±C26)a (+) (+) (+) +
Homologous series ofiso-alkanoic acids (C12±C20) + (+) (+) +
Homologous series ofanteiso-alkanoic acids (C12±C20) + (+) (+) +
9-Hexadecenoic acid, palmitoleic acida + +
9,12,15-Octatrienoic acid, linolenic acida + +
9,12-Octadienoic acid, linoleic acida
9-Octadecenoic acid, oleic acida + + + +
Eicosatetraenoic acid, arachidonic acida +
Eicosapentaenoic acidd +
Phenylacetic acida + + + + +
Esters
Complex mixture of wax esters (C27to C32)d (+) + + + +
Methyldodecanoatea + + +
Methyltetradecanoatea + + +
Methyl-iso-pentadecanoatee + + +
Methyl-anteiso-pentadecanoatee + + +
Methylpentadecanoatea + + +
Methyl-iso-hexadecanoatee + + +
Methylpalmitoleatea + +
Methylhexadecanoatea + + +
Methyl-iso-heptadecanoatee + +
Methyl-anteiso-heptadecanoatee + +
Methylheptadecanoatea + + +
Methyloleatea + +
Methyloctadecanoatea + + +
Methyleicosanoatea + +
Isopropyldodecanoatee + +
Isopropyltetradecanoatee + + + + + +
Isopropylhexadecanoatee + + +
Dibutyl-2-butenoatee + + +
Amides
Pentadecanamidee + + + +
Hexadecanamidea + + + + + + +
Heptadecanamidee + + + + + + +
Table 2 (continued)
Compounds A B C D E F G
Ethylmethylmaleimidee + + + + +
Tocopherols and degradation products
a-Tocopherola + + + + + + +
3,4-Dimethyl-2,5-furandionea + + +
4,8,12,16-Tetramethylheptadecan-4-olidea + + + + + + +
Plasticizers
Dimethylphthalatea + + + + + + +
Dimethylterephthalatea + + + + + + +
Diethylphthalatea + + + + + + +
Di-iso-butylphthalatea + + + + + + +
Di-n-butylphthalatea + + + + + + +
Bis(2-ethylhexyl)phthalatea + + + + + + +
2,4,4-Trimethylpentan-1,3-diol-diisobutyratea + + + + +
Tributylphosphatea + + + + + +
Complex mixture of alkylsulfonic acid phenylesters (C12to C18side chains)a (+) +
Fragrances and UV-protectors
Galaxolidea + + + + + + +
Tonalidea + + + + + + +
2,6,6-Trimethyl-2-cyclohexen-1,4-dionea + + + + + +
1,2,3,6,7,8-Hexahydro-1,1,6,6-tetramethyl-4-isopropyl-as-indacene +
4-Methoxycinnamic acid 2-ethylhexyl estera + + + + + +
Halogenated compounds
Complex mixture of tetra- to heptachlorinated biphenylsa,d + + (+) (+) + + +
Hexachlorobutadienea + +
1,3-Dichlorobenzenea + + + + + + +
1,4-Dichlorobenzenea + + + + + + +
1,2-Dichlorobenzenea + + + + + + +
1,3,5-Trichlorobenzenea + + + + + + +
1,2,4-Trichlorobenzenea + + + + + + +
1,2,3,5-/1,2,4,5-Tetrachlorobenzenea + + + +
1,2,3,4-Tetrachlorobenzenea + + + +
Pentachlorobenzenea + + + + +
Hexachlorobenzenea + + + + +
4,40-Dichlorodiphenylsul®dea + + + + +
1-Chloronaphthalenea + + +
1,4-Dichloronaphthalenea + + +
1,5-/1,6-Dichloronaphthalenea + +
1,7-/2,6-/2,7-Dichloronaphthalenea + +
Bromophenold +
Pesticides and degradation products
4,40-DDMUa +
4,40-DDEa + + +
4,40-DDDa + + + + + +
Organometallic compounds
Tetrabutyltina + + + + +
a Identi®ed by comparison of gas chromatographic and mass spectral data with those of reference compounds.
b Identi®ed by comparison of gas chromatographic and mass spectral data with those of mass spectral data bases and published
retention indices.
c Identi®ed by comparison of gas chromatographic and mass spectral data with those of mass spectral data bases and published gas
chromatographic elution patterns.
d Molecular structure is not more speci®ed.
e Identi®ed by comparison of mass spectral data with those of mass spectral data bases. f Only molecular masses of the parent PAH are given.
3.1. Commonly observed organic compounds in coastal sediments of the German Bight
Biological activity in the German Bight produces several groups of low molecular lipophilic compounds deposited in the surface sediments together with land-derived organic matter. Carotenoid degradation products (e.g. ionenes, dihydroactinidiolide ) and compounds structu-rally related to phytol (e.g. pristane, phytane, phytene, phytadiene, 6,10,14-trimethylpentadecan-2-one, 4,8,12-trimethyltetradecanoic acid) were observed. Also fatty acids from C9to C26were identi®ed as main components
in the ®fth liquid chromatographic fraction. Next to the n-alkanoic acids, several methyl branched acids with anteiso andisosubstitution (chain length from C12 to
C17) as well as the unsaturated components, palmitoleic
acid, linolenic acid, linoleic acid, oleic acid, arachidonic acid and an eicosapentaenoic acid, were detectable at most of the sampling locations. It is well known that these classes of biogenic compounds detected in lacus-trine sediments are derived from both autochthonous and allochthonous emission and are, therefore, of mar-ine and terrigenous origin (Cranwell, 1981a; Cranwell et al., 1987; Riley et al., 1991). In addition, complex mixt-ures of wax esters with chain lengths from C27 to C32
could be detected in sediment samples of sites B, F,G,and E. The mass spectral data and gas chromatographic
properties (Fig. 3) suggest an isomer distribution similar to that described by Cranwell (1981b), who assumed that the wax esters were produced by microbial activity.
Terpenoids are not always diagnostic of biogenic contributions to the organic matter in sediments. Wide-spread use of monoterpenoic compounds in products such as perfumes and odour agents (e.g. mixtures ofa -andb-ionenes, limonene), in organic solvents (oil of tur-pentine) and as plasticizers (e.g. campher, fenchone) and the resulting discharge into riverine systems prevents an absolute association of such compounds with natural sources. Also a-tocopherol, detected in all sediment extracts, could not be associated only with biogenic sources because of its widespread use as an antioxidant and vitamin in food as well as food supplements (Egan-house and Kaplan, 1985). The occurrence of 3,4-dime-thyl-2,5-furandione and 4,8,12,16-tetramethylheptadecan-4-olide, previously described as oxidation products for the structure elucidation of tocopherols (Fernholz, 1938), suggests a possible oxidative degradation of a -tocopherol in the aquatic environment.
Long chain n-aldehydes (C9±C32) found at sampling
locations A,B and G, situated near to the estuaries of the Elbe and Ems rivers, could be indicative of the con-tribution of terrestrial organic matter. Such long-chain n-aldehydes (C20±C32) with even-to-odd carbon chain
length predominance have been attributed to the input
of terrestrial plant waxes, whereas the origin ofn- alde-hydes with shorter side chains is not known (Prahl and Pinto, 1987; Stephanou, 1989). In the studied sediments the homologous series of the n-aldehydes show a dis-tribution in the range from C20 to C32 according to
previously published results (Fig. 4). N-aldehydes of lower molecular weight (C9±C19) maximizing at C10and
C15 occurred in the same concentration range as the
higher homologous, but a carbon chain length pre-dominance is not observable. In sample A, mainly in¯u-enced by the Elbe river, the composition ofn-aldehydes was dierent to that of sample G, which is situated near the estuary of the Ems Rivers. In both samples dis-tributions maximized at C26, but the even-over-odd
predominance is higher at sample location G. Also the amount of short-chainn-aldehydes (C9±C18) relative to
the long-chain components (C19±C32) in sample G is
greater than in sediments from sample site A. The pre-sence ofn-aldehydes in sediments from sampling loca-tion E indicates a terrigenous contribuloca-tion at this site too. The homologous pattern in this sample could be constructed by mixing of the n-aldehydes at sampling location A and G. Accordingly, the land-derived organic matter at site E seemed to originate from the Elbe river as well as from the Ems and Weser rivers.
In addition, the occurrence of n-alkan-2-ones (C23±
C29) at sampling locations A,B,E and G suggested
ter-rigenous contributions to the coastal sediments due to the proposed formation by microbial b-oxidation of corresponding higher plant derivedn-alkanes (Allen et al., 1971; Cranwell, 1981a; Riley et al., 1991).
A second group of lipophilic compounds in sediments of the German Bight were petrogenic substances. The distributions of hopanoids and steranes identi®ed in the
sediment samples (Fig. 5) were indicative of petrogenic input due to their unique structures, persistence and well known diagenetic and catagenetic transformations (Volkman et al., 1997). For instance the occurrence of C31- to C33-hopanes with similar concentrations of
22R-and 22S-isomers as well as the ratio of trisnorhopanes (Ts/Ts-Tm) is characteristic of thermally mature organic
material that could only be introduced to recent sedi-ments by contamination from fossil fuels. Unresolved complex mixtures (UCM's) are generally observed in the aliphatic fractions. These UCMs and high amounts of alkylated cyclohexanes and benzenes also re¯ect the contribution of petrogenic emissions, whereas the pet-rogenic n-alkanes were superposed by biogenic con-tributions indicated by an odd-over-even carbon chain length predominance. A successful dierentiation of aliphatic hydrocarbons from both biogenic and petro-genic sources in coastal sediments is rather dicult (Fernandes et al., 1997; Tran et al., 1997).
Polycyclic aromatic compounds (PACs) are ubiqui-tous contaminants in several environmental compart-ments. In coastal sediments, direct input of PAC by atmospheric deposition or discharge of petroleum products is supplemented by riverine contribution of urban and industrial euents as well as urban runo containing PACs from asphalt and car exhaust parti-cles (Mattiasson et al., 1977; Wakeham et al., 1980; Wang et al., 1995; Bence et al., 1996; Aboul-Kassim and Simoneit, 1996; Burns et al., 1997; Dachs et al., 1997). In sediments of the German Bight we identi-®ed di- to hexacyclic aromatic compounds accom-panied by C1- to C3-substituted isomers in the same
concentration range. Pyrogenic PACs originating from incomplete combustion processes are represented by a predominance of ¯uoranthene and pyrene as well as ®ve- and six-membered ring compounds in the fourth chromatographic fraction of each sediment extract. PACs of fossil origin are indicated by high amounts of naphthalene, phenanthrene and alkylated isomers of several parent polycyclic aromatic hydrocarbons that were main components in the third chromatographic fraction.
Hydrogenated PACs were identi®ed in minor con-centrations such as tetralin, decalin, 1,1,6-trimethylte-tralin and hydrogenated biphenyls. Nitrogen-, sulphur-and oxygen-containing PAC with alkylated isomers occurring in higher amounts were indicative for organic matter of fossil origin. Sulphur containing PACs are well documented constituents of crude oils and petro-genic products (e.g. Grimmer et al., 1981a,b; Later et al., 1981; Glinzer et al., 1983; Arpino et al., 1987; Wang and Fingas, 1995; Chakhmakhchev et al., 1997). The identi®ed oxygenated PACs, cyclopenta(def)phenanthren-4-one, 9,10-anthraquinone and benzanthrone, probably originate from oxidation of polycyclic aromatic hydro-carbons during incomplete combustion or atmospheric
transport (Schuetzle et al., 1981; KoÈnig et al., 1983; Tong and Karasek, 1984).
In addition to biogenic and petrogenic compounds, a wide variety of anthropogenic substances were identi-®ed. Several low molecular weight organic compounds representing domestic source contamination were intro-duced to the coastal sediments by riverine discharge. Methyl and isopropyl esters of fatty acids originating from soaps and washing agents are main components of household euents (Paxeus, 1996). Their occurrence is associated with anthropogenic emissions and further-more riverine contribution to coastal sediments. Also the higher concentrations of coprostanone in comparison to cholestanone suggest contributions from sewage eu-ents and are, therefore, indicative for organic matter of riverine origin (Chalaux et al., 1995; Takada et al., 1997; Chan et al., 1998). Major components in the ®fth liquid chromatographic fraction of each analysed sediment extract were a group of plasticizers, including phtha-lates, 2,4,4-trimethylpentan-1,3-diol-diisobutyrate and tributylphosphate. These compounds are well known ubiquitous pollutants and were also detected in Elbe river water (Franke et al., 1995). Fragrances and odor-ants also indicate municipal and, therefore, land derived contamination in coastal sediments. In the sediment samples from the German Bight we identi®ed in most samples the musk fragrances galaxolide and tonalide used as odorants in detergents as well as 2,6,6-trimethyl-2-cyclohexen-1,4-dione (4-oxoisophorone). This com-pound is industrially produced via oxidation of iso-phorone and mainly used in perfumes (Papa and Sherman, 1981). In addition a 2-ethylhexyl ester of 4-methoxycinnamic acid was frequently identi®ed which is commonly used as a UV-protector in cosmetics. Further-more a group of organic contaminants could be detected at all sample locations re¯ecting the widespread use of synthetic detergents. Linear alkylbenzenes (LABs), with side chain length from C10to C13, are common detergent
residues due to their use as a raw material for the synth-esis of the alkylbenzenesulfonate surfactants and are therefore useful anthropogenic markers for domestic waste emissions (Takada and Eganhouse, 1998, and references cited therein). The isomeric composition of LABs (Fig. 6) diers from the pattern of technical for-mulations because of the more rapid degradation of external isomers (phenyl group attached near the end of the alkyl chain, e.g. 2- and 3-substitution) in comparison to internally substituted isomers (phenyl group attached near the middle of the alkyl chain, e.g. 5- and 6-substitu-tion). The relatively decreasing abundance of external isomers described as increasing I/E-ratio has been used as indicator for the state of LAB degradation in the aquatic environment (Takada and Ishiwatari, 1990).
Also alkylated benzenes (C10-14-benzenes) with
times and dierent mass spectral data of these com-pounds in comparison to those of LABs and TABs indi-cated a multiple substitution at the benzene ring.
Well known halogenated organic pollutants of anthropogenic origin include the polychlorinated biphe-nyls (PCBs) frequently used in a wide range of technical applications. Low aqueous solubility, low vapor pressure
dation result in the ubiquity of PCBs in aquatic sedi-ments (Lang, 1992). In each sample investigated in this study a complex mixture of tetra- to heptachlorinated congeners could be identi®ed by gas chromatographic analyses with simultaneous electron capture and ¯ame ionisation detection (ECD/FID). The individual con-generic composition corresponding to technical mixtures
All anthropogenic land-derived contaminants descri-bed above are mainly introduced to the coastal sedi-ments by atmospheric deposition and in higher quantity by riverine contributions. But these compounds can only be linked to multiple sources or widespread tech-nical use and are, therefore, inappropriate to assess the discharge of the Elbe river to the German Bight.
3.2. Potential organic molecular marker compounds for estimating the contribution of the Elbe river
Beside the components described above several com-pounds could be identi®ed that seemed to be indicative of the contribution of the Elbe river to the pollution of the sediments in the German Bight (Table 3). The use of these compounds as potential Elbe-speci®c markers is, however, limited because of the limited information about the organic matter derived from other rivers also discharging into the German Bight.
Two classes of substances are appropriate as Elbe-speci®c marker compounds: 1. common compounds only detected in high amounts at the locations close to the Elbe river (A,B), and 2. compounds with speci®c molecular structures that are not ubiquitous taminants or have been described formerly as con-taminants of the Elbe river.
A well known Elbe-speci®c compound is tetrabutyl tin, the parent substance for the synthesis of mono- to tributyl tin compounds widely used as antifoulants, sta-bilizers in poly(vinyl chloride)s (PVC) and industrial as well as agricultural biocides. The origin of tetrabutyl tin in sediments and suspended particulate matter of the Elbe river can be linked to an industrial point source situated near the con¯uence of the Mulde and the Elbe rivers (Wilken et al., 1994, Schwarzbauer, 1997). The occurrence of tetrabutyl tin not only at sample sites mainly in¯uenced by the Elbe river (sample sites A,B and C), but also in sediments situated farer from the Elbe estuary (sample sites E,F) indicates a wide spatial
distribution of Elbe-derived organic matter in the Ger-man Bight.
Also 1,2,3,6,7,8-hexahydro-1,1,6,6-tetramethyl-4-iso-propyl-as-indacene, attributed to a group of synthetic fragrances, can be used as Elbe-speci®c tracer molecule. It was detectable only at sampling location B, whereas 4-oxoisophorone, 2,4,4-trimethylpentan-1,3-diol-diiso-butyrate and the musk fragrances, galaxolide and tona-lide, are ubiquitous contaminants of both the Elbe river (Franke et al., 1995) and the sediments investigated in this study. The indacene compund is part of the large emission of an industrial plant situated near the Mulde river (Schwarzbauer, 1997).
As described above, plasticizers were main compo-nents in all gas chromatograms of the semi-polar and polar fractions obtained from the sediment samples. Examples include phthalates, tributyl phosphate and in addition a technical mixture of alkylsulfonic acid phe-nylesters. These arylesters were detected recently in high amounts in sediments as well as in the particulate matter of the Elbe system (Franke et al., 1998). We detected these plasticizers only at sampling locations A and B with a pattern similar to the isomeric distribution found in the Elbe river (Franke et al., 1998). The sample sites A and B are most in¯uenced by the Elbe river and, therefore, we suggest that alkylsulfonic acid pheny-lesters are Elbe-speci®c.
With respect to halogenated compounds, several sub-stances were identi®ed that are also frequently found in sediments of the Elbe river (Schwarzbauer, 1997). Chlorinated benzenes with 2±6 chlorine substituents were identi®ed in sediments of the Elbe river as well as in the samples of the German Bight. Dichloro- and tri-chlorobenzenes are used as synthetic raw material for many technical products such as antiseptic agents, sol-vents and additives (Bryant, 1993). These compounds were detected in all samples and are, therefore, not Elbe-speci®c. On the contrary higher substituted congeneres appeared at sample sites A,B,C,E and F, but not at sample sites D and G, which are mainly in¯uenced by input of the Ems river. The occurrence of tetra- and pentachlorbenzenes in the environment is not attributed to speci®c sources due to industrial processes or techni-cal applications. Only hexachlorobenzene is well known as a formerly used herbicide and synthetic by-product in a number of organic syntheses (Bryant, 1993; SchloÈr, 1970). Therefore, the appearance of tetrachloro- to hexachlorobenzenes in the sample sites described above could be suggestive for Elbe-speci®c contribution of organic matter.
Mono- and disubstituted chloronaphthalenes with patterns related to those of technical agents (e.g. Halo-wax 1000) may be appropriate as Elbe-speci®c mole-cular markers due to their presence only at locations A,B and C. Although the occurrence of only low chlorinated naphthalenes is rarely reported (Falandysz,
Table 3
Potential organic marker compounds of the Elbe river
Halogenated compounds
Nonhalogenated compounds
4,40-Dichlorodiphenylsul®de Complex mixture of
alkylsulfonic phenylesters
Tetrachlorobenzenes
1,2,3,6,7,8-Hexahydro- 1,1,6,6-tetramethyl-4-isopropyl-as -indacene
Pentachlorobenzene Tetrabutyl tin
Hexachlorobenzene
1-Chloronaphthalene
Dichloronaphthalenes
1998), these substances were identi®ed in sediments of the Elbe river (Schwarzbauer, 1997) as well as in the sediment samples described above. In contrast higher chlorinated naphthalenes with up to 8 chlorine atoms were detected frequently in several environmental com-partments (Falandysz, 1998).
Beside the congeneric groups of chlorinated aromatic substances, individual halogenated compounds such as 4,40-dichlorodiphenylsul®de and hexachlorobutadiene, a known organic agent used as solvent and in hydraulic ¯uids (Koch, 1995), could only be detected at sample sites A,B and C. The origin of 4,40-dichlorodiphenyl sul®de in sediments of the Elbe river and in the investigated samples of the German Bight is still unknown.
To a minor degree degradation products of the pesti-cide DDT might be useful Elbe-speci®c marker com-pounds, because of the longer period of DDT application in the catchment area of the Elbe river in contrast to the Weser and Ems rivers and the high con-centration of DDD and DDE found in water as well as suspended particulate matter of the Elbe river (Goetz et al., 1994). The para-substituted isomer of DDE could be detected only in sediment samples mainly in¯uenced by the Elbe river (sites A,B,C), whereas 4,40-DDD occurred additionally at sites D, E and F, but not at site G that is in¯uenced by the Weser river.
4. Summary and conclusion
Detailed screening analyses revealed a wide variety of organic lipophilic compounds of biogenic, petrogenic and anthropogenic origin in sediments of the German Bight. The biological activity in the marine environment is be re¯ected by the occurrence of several compounds, e.g. carotenoids, fatty acids and wax esters. Con-tamination of petrogenic origin are indicated by an iso-meric distribution of saturated steranes and hopanes, characteristic fossil markers occurring in high amounts in the examined sediments. Substances indicating the terrestrial input of low molecular organic matter to the coastal sediments might be both biogenic long chain n-aldehydes and isomers with shorter side chains of unknown origin. Also several anthropogenic com-pounds characterized the land-derived contribution to the organic matter in the coastal sediments. Sewage-speci®c marker compounds include coprostanone, linear alkylbenzenes, plasticizers and fragrances.
Speci®c organic marker compounds indicating the contribution of the Elbe river to the pollution in sedi-ments of the German Bight were attributed mainly to chlorinated aromatic contaminants. Speci®cally, tetra- to hexachlorbenzenes, mono- and dichloronaphthalenes, hexachlorobutadiene and 4,40-dichlorodiphenylsul®de
were useful in describing the spatial distribution of Elbe-derived organic matter.
Also, an isomeric mixture of alkylsulfonic acid phe-nylesters, the individual contaminants tetrabutyl tin and 1,2,3,6,7,8-hexahydro-1,1,6,6-tetramethyl-4-isopropyl-as-indacene as well as degraded compounds of DDT could be attributed to the group of Elbe-speci®c marker compounds.
All identi®ed Elbe-speci®c substances are only poten-tial molecular markers at present, because marker com-pounds re¯ecting the input of the Weser and the Ems river to the sediments of the German Bight are not known.
Acknowledgements
The authors would like to acknowledge a very helpful and thorough review of this manuscript by R.P. Egan-house.
References
Aboul-Kassim, T.A.T., Simoneit, B.R.T., 1996. Aliphatic and aromatic hydrocarbons in particulate fallout of Alexandria, Egypt: sources and implications. Environmental Science & Technology 29, 2473±2483.
Allen, J.E., Forney, F.W., Markovetz, A.J., 1971. Microbial subterminal oxidation of alkanes and alk-1-enes. Lipids 6, 448±452.
Alberts, J.J., TakaÂcs, M., 1999. Importance of humic sub-stances for carbon and nitrogen transport into southeastern United States estuaries. Organic Geochemistry 30, 385±396. Arpino, P.J., Ignatiadis, I., de Ryke, G., 1987.
Sulphur-containing polynuclear aromatic hydrocarbons from petro-leum. Examination of their possible statistical formation in sediments. Journal of Chromatography 390, 329±348. Ballschmitter, K., SchaÈfer, W., Buchert, H., 1987.
Isomer-spe-ci®c identi®cation of PCB congeners in technical mixtures and environmental samples by ECD and HRGC-MSD. Fresenius Journal of Analytical Chemistry 326, 253± 257.
Bence, A.E., Kvenvolden, K.A., Kennicutt, M.C., 1996. Organic geochemistry applied to environmental assessments of Prince William Sound, Alaska, after the Exxon Valdez oil spill Ð a review. Organic Geochemistry 24, 7±42.
Bester, K., HuÈhnerfuss, H., Lange, W., Rimkus, G.G., Theo-bald, N., 1998. Results of non-target screening of lipophilic organic pollutants in the German Bight II: polycyclic musk fragrances. Water Research 32, 1857±1863.
Bester, K., HuÈhnerfuss, H., Lange, W., Theobald, N., 1997. Results of non-target screening of lipophilic organic pollutants in the German Bight I: benzthiazoles. Science of the Total Environment 207, 111±118.
(Eds.) Kirk-Othmer Ð Encyclopedia of Chemical Technol-ogy 6, 4th Edition. John Wiley & Sons, New York, pp. 87-101.
Bundt, J., Herbel, H., Steinhart, H., Franke, S., Francke, W., 1991. Structure-type separation of diesel fuels by solid phase extraction and identi®cation of the two- and three-ring aro-matics by capillary GC±mass spectrometry. Journal of High Resolution Chromatography 14, 91±98.
Burns, W.A., Mankiewicz, P.J., Bence, E.A., Page, D.S., Par-ker, K.R., 1997. A principal-component and least-squares method for allocating polycyclic aromatic hydrocarbons in sediment to multiple sources. Environmental Science & Technology 16, 1119±1131.
Chakhmakhchev, S., Suzuki, M., Takayama, K., 1997. Dis-tribution of alkylated dibenzothiophenes in petroleum as a tool for maturity assessments. Organic Geochemistry 26, 483±490.
Chalaux, N., Takada, H., Bayona, J.M., 1995. Molecular mar-kers in Tokyo Bay sediments: sources and distribution. Marine Environmental Research 40, 77±92.
Chan, K.-H., Lam, M.H.W., Poon, K.-F., Yeung, H.-Y., Chiu, T.K.T., 1998. Application of sedimentary fecal stanols and sterols in tracing sewage pollution in coastal waters. Water Research 32, 225±235.
Cranwell, P.A., 1981a. Diagenesis of free and bound lipids in terrestrial detritus deposited in a lacustrine sediment. Organic Geochemistry 3, 79±89.
Cranwell, P.A., 1981b. Alkyl esters in recent sediments of two productive lakes. In: Bjoroy, M. et al. (Eds.), Advances in Organic Geochemistry 1981. John Wiley & Sons, Chichester, pp. 299±308.
Cranwell, P.A., Eglinton, G., Robinson, N., 1987. Lipids of aquatic organism as potential contributors to lacustrine sediments Ð II. Organic Geochemistry 11, 513±527. Dachs, J., Bayona, J.M., Raoux, C., AlbaigeÂs, J., 1997. Spatial,
vertical distribution and budget of polycyclic aromatic hydrocarbons in the Western Mediterranean seawater. Environmental Science & Technolology 31, 682±688. Eganhouse, R.P., 1997. Molecular markers and environmental
organic geochemistry: an overview. In: Eganhouse, R.P. (Ed.), Molecular markers in Environmental Geochemistry. ACS Symposium Series 671, Washington, DC, pp. 1±21. Eganhouse, R.P., Kaplan, I.R., 1985.a-Tocopherol acetate as
an indicator of municipal waste contamination in the envir-onment. Environmental Science & Technolology 19, 282±285. Falandysz, J., 1998. Polychlorinated naphthalenes: an
environ-mental update. Environenviron-mental Pollution 101, 77±90. Fernandes, M.B., Sicre, M.A., Boireau, A., Tronczynski, J.,
1997. Aquatic hydrocarbon distributions in the Seine estu-ary: biogenic polyaromatics and n-alkanes. Estuaries 20, 281±290.
Franke, S., Schwarzbauer, J., Francke, W., 1998. Arylesters of alkylsulfonic acids in sediments. Fresenius Journal of Analy-tical Chemistry 360, 580±588.
Franke, S., Hildebrandt, S., Schwarzbauer, J., Link, M., Francke, W., 1995. Organic compounds as contaminants of the Elbe river and its tributaries. Fresenius Journal of Ana-lytical Chemistry 353, 39±49.
Fernholz, E., 1938. On the constitution ofa-tocopherol. Jour-nal of the American Chemical Society 60, 700±705. Gatermann, R., Bester, K., Franke, S., HuÈhnerfuss, H., 1996.
The distribution of O,O,O-trimethylthiophosphate and O,O,S-trimethyldithiophosphate in the North Sea. Chemo-sphere 32, 1907±1918.
Gatermann, R., HuÈhnerfuss, H., Rimkus, G., Wolf, M., Franke, S., 1995. The distribution of nitrobenzene and other nitroaromatic compounds in the North Sea. Marine Pollu-tion Bulletin 30, 221±227.
Glinzer, O., Severin, D., BeduÈrftig, C., Czogalla, C.D., Puttins, U., 1983. Mass spectrometry of sulphur compounds as model substances for crude oil analysis Ð bisanellated thio-phenes. Fresenius Journal of Analytical Chemistry 315, 208± 212.
Goetz, R., Friesel, P., Roch, K., Ebel, C., Siebert, J., Reincke, H. et al., 1994. Pesticides in the river Elbe, in tributaries of the river Elbe and in small surface waters of the River Elbe catchment area. Vom Wasser 83, 43±55.
Grimmer, G., Jacob, J., Naujack, K.W., 1981a. Pro®le of the polycyclic aromatic hydrocarbons from lubricating oil Ð inventory by GC/MS. Fresenius Zeitschrift der Analytischen Chemie 306, 347±355.
Grimmer, G., Jacob, J., Naujack, K.W., Dettborn, G., 1981b. Pro®le of the polycyclic aromatic hydrocarbons from used engine oil Ð inventory by GC/MS. Fresenius Zeitschrift der Analytischen Chemie 309, 13±19.
Gupta, L.P., Subramanian, V., Ittekkot, V., 1997. Bio-geochemistry of particulate matter transported by the God-avaria River. Biogeochemistry 38, 103±128.
Hedges, J.I., Keil, R.G., Benner, R., 1997. What happens to terrestrial organic matter in the ocean? Organic Geochem-istry 27, 195±212.
Hedges, J.I., Parker, P.L., 1976. Land-derived matter in surface sediments from the Gulf of Mexico. Geochimica et Cosmo-chimica Acta 40, 1019±1029.
Ittekkot, V., 1988. Global trends in the nature of organic mat-ter in river suspensions. Nature 332, 436±438.
Ittekkot, V., Arain, R., 1986. Nature of particulate organic matter in the river Indus, Pakistan. Geochimica et Cosmo-chimica Acta 50, 1643±1653.
Keil, R.G., Mayer, L.M., Quay, P.D., Richey, J.E., Hedges, J.I., 1997. Loss of organic matter from riverine particles in deltas. Geochimica et Cosmochimica Acta 61, 1507±1511. Koch, R., 1995. Umweltchemikalien, 3rd Ed.. VCH,
Wein-heim.
KoÈnig, J., Balfanz, E., Funcke, W., Romanowski, T., 1983. Determination of oxygenated polycyclic aromatic hydro-carbons in airborne particulate matter by capillary gas chro-matography and gas chrochro-matography/mass spectrometry. Analytical Chemistry 55, 599±603.
Lang, V., 1992. Polychlorinated biphenyls in the environment. Journal of Chromatography 595, 1±43.
Later, D.W., Lee, M.L., Bartle, K.D., Kong, R.C., Vassilaros, L., 1981. Chemical class separation and characterization of organic compounds in synthetic fuels. Analytical Chemistry 53, 1612±1620.
Mattiasson, B., Larsson, P.O., Mosbach, K., 1977. Polycyclic aromatic hydrocarbons in long-range transported aerosols. Nature 268, 518±520.
Paschke, A., Herbel, W., Steinhart, H., Franke, S., Francke, W., 1992. Determination of mono- to tetracyclic aromatic hydrocarbons in lubricating oil. Journal of High Resolution Chromatography 15, 827±833.
Paxeus, N., 1996. Organic pollutants in the euents of large wastewater treatment plants in Sweden. Water Research 30, 1115±1122.
Peters, K.E., Moldowan, J.M., 1993. The Biomarker Guide : Interpreting Molecular Fossils in Petroleum and Ancient Sediments, Prentice Hall, Englewood Clis, NJ.
Prahl, F.G., Pinto, L.A., 1987. A geochemical study of long-chain n-aldehydes in Washington coastal sediments. Geochi-mica et CosmochiGeochi-mica Acta 51, 1573±1582.
Riley, G., Collier, R.J., Jones, D.M., Eglinton, G., 1991. The biogeochemistry of Ellesmere Lake U.K. Ð I: Source corre-lation of leaf wax inputs to the sedimentary lipid record. Organic Geochemistry 17, 901±912.
Rostad, C.E., Pereira, J., 1986. Kovats and Lee retention indi-ces determined by gas chromatography/mass spectrometry for organic compounds of environmental interest. Journal of High Resolution Chromatography 9, 328±334.
SchloÈr, H., 1970. Chemie der Fungizide. In: Wegler, R. (Ed.), Chemie der P¯anzenschutz- und SchaÈdlingsbekaÈmpfungsmittel 2, Springer Verlag, Berlin, pp. 45±156.
Schuetzle, D., Lee, F.S.C., Prater, T.J., 1981. The identi®cation of polynuclear aromatic hydrocarbon (PAH) derivatives in mutagenic fractions of diesel particulate extracts. International Journal of Environmental Analytical Chemistry 9, 93±144. Schwarzbauer, J., 1997, Thesis, University of Hamburg. Stephanou, E., 1989. Long-chain n-aldehydes.
Naturwissen-schaften 76, 464±467.
Takada, H., Eganhouse, R.P., 1998. Molecular markers of anthropogenic waste. In: Meyers, R.A. (Ed.), Encyclopedia of Environmental Analysis and Remediation. John Wiley and Sons, New York, pp. 2883±2940.
Takada, H., Ishiwatari, R., 1990. Biodegradation experiments of linear alkylbenzenes (LABs): isomeric composition of C12
LABs as an indicator of the degree of LAB degradation in the aquatic environment. Environmental Science & Technol-ogy 24, 86±91.
Takada, H., Satoh, F., Bothner, H., Tripp, B.W., Johnson, C.G., Farrington, J.W., 1997. Anthropogenic molecular markers: tools to identify the sources and transport pathways of pollutants. In: Eganhouse, R.P. (Ed.), Molecular Markers in Environmental Geochemistry. ACS Symposium Series 671, Washington, DC, pp. 178±195.
Theobald, N., Lange, W., GaÈhlert, W., Renner, F., 1995. Mass spectrometric investigations of water extracts of the river Elbe for the determination of potential inputs of pollutants into the North Sea. Fresenius Journal of Analytical Chem-istry 353, 50±56.
Tong, H.Y., Karasek, F.W., 1984. Quanti®cation of polycyclic aromatic hydrocarbons in diesel exhaust particulate matter by high-performance liquid chromatography fractionation and high-resolution gas chromatography. Analytical Chem-istry 56, 2129±2134.
Tran, K., Yu, C.C., Zeng, E.Y., 1997. Organic pollutants in the
coastal environment of San Diego, California. 2. Petrogenic and biogenic sources of aliphatic hydrocarbons. Environ-mental Toxicology and Chemistry 16, 189±195.
Vassilaros, D.L., Kong, R.C., Later, D.W., Lee, M.L., 1982. Linear retention index system for polycyclic aromatic com-pounds. Critical evaluation and additional indices. Journal of Chromatography 252, 1±20.
Volkman, J.K., Revill, A.T., Murray, A.P., 1997. Applications of biomarkers for identifying sources of natural and pollu-tant hydrocarbons in aquatic environments. In: Eganhouse, R.P. (Ed.), Molecular Markers in Environmental Geochem-istry. ACS Symposium Series 671, Washington, DC, pp. 110±133.
Wakeham, S.G., Schaner, C., Giger, W., 1980. Polycyclic aromatic hydrocarbons in recent lake sediments Ð I. Com-pounds having anthropogenic origins. Geochimica Cosmo-chimica Acta 44, 403±413.
Wang, Z., Fingas, M., Li, K., 1994. Fractionation of a light crude oil and identi®cation and quanti®cation of aliphatic, aromatic and biomarker compounds by GC±FID and GC± MS, Part 2. Journal of Chromatographic Science 32, 367± 382.
Wang, Z., Fingas, M., 1995. Use of methyldibenzothiophenes as markers for dierentiation and source identi®cation of crude and weathered oils. Environmental Science & Tech-nology 29, 2842±2849.
Wang, Z., Fingas, M., Sergy, G., 1995. Chemical characteriza-tion of crude oil residues from an Arctic beach by GC/MS and GC/FID. Environmental Science & Technology 29, 2622±2631.
Wilken, R.-D., Kuballa, J., Jantzen, E., 1994. Organotins: their analysis and assessment in the Elbe river system, northern Germany. Fresenius Journal of Analytical Chemistry 350, 77±84.
Yunker, M.B., MacDonald, R.W., Fowler, B.R., Cretney, W.J., Dallimore, S.R., McLaughlin, F.A., 1991. Geochem-istry and ¯uxes of hydrocarbons to the Beaufort sea shelf: a multivariate comparison of ¯uvial inputs and coastal erosion of peat using principal components analysis. Geochimica et Cosmochimica Acta 55, 255±273.
Yunker, M.B., MacDonald, R.W., Cretney, W.J., Fowler, B.R., McLaughlin, F.A., 1993. Alkane, terpene and poly-cyclic aromatic hydrocarbon geochemistry of the Mackenzie river and Mackenzie shelf:riverine contributions to Beaufort sea coastal sediment. Geochimica Cosmochimica Acta 57, 3041±3061.
Zegouagh, Y., Derenne, S., Largeau, C., Saliot, A., 1996. Organic matter sources and early diagenetic alterations in Arctic surface sediments of Lena river delta and Laptev sea, eastern Siberia., II. Analysis of the carboxylic acids released via sequential treatments. Organic Geochemistry 24, 841± 857.
