Unresolved Complex Mixture Of Hydrocarbons Research Articles

Oil leakage induces changes in microbiomes of deep-sea sediments of Campos Basin (Brazil)

The Campos Basin (100,000 km2) is located on the continental shelf of southeastern Brazil. Despite the significant oil and gas industrial activities underway in the Campos Basin, scarce information is available regarding the hydrocarbon contents and microbial communities in the deep-sea sediments. To gain new insights on these aspects, we first obtained deep-sea sediment samples with different degrees of oil exposure. We obtained samples from a seabed fissure (N = 28), surroundings (250 m to 500 m from the fissure; N = 24), and a control area (N = 4). We used shotgun metagenomics to characterize the taxonomic and metabolic diversity and analyzed biogeochemical parameters (metal and oil concentration) of all samples. The high levels of unresolved complex mixture of hydrocarbons in the fissure indicate a potentially recent petrogenic contribution in these sediments. The fissure area was found to have a higher abundance of hydrocarbonoclastic bacterial genera and hydrocarbon degradation genes. These bacteria may be used as biosensors of sediment contamination. The effects of oil contamination, mainly around the fissure, are less clear at 250 m and 500 m, suggesting that the surroundings may not have been heavily affected by the oil leakage. Our study demonstrates that metagenomics can disclose biosensors for environmental monitoring.

Dysregulation of photosynthetic genes in oceanic Prochlorococcus populations exposed to organic pollutants

The impact of organic pollutants on oceanic ecosystem functioning is largely unknown. Prochlorococcus, the most abundant known photosynthetic organism on Earth, has been suggested to be especially sensible to exposure to organic pollutants, but the sub-lethal effects of organic pollutants on its photosynthetic function at environmentally relevant concentrations and mixtures remain unexplored. Here we show the modulation of the expression of two photosynthetic genes, rbcL (RuBisCO large subunit) and psbA (PSII D1 protein), of oceanic populations of Prochlorococcus from the Atlantic, Indian and Pacific Oceans when exposed to mixtures of organic pollutants consisting of the non-polar fraction of a seawater extract. This mixture included most persistent organic pollutants, semivolatile aromatic-like compounds, and the unresolved complex mixture of hydrocarbons. Prochlorococcus populations in the controls showed the expected diel cycle variations in expression of photosynthetic genes. However, exposure to a complex mixture at concentrations only 2-fold above the environmental levels resulted in a decrease of expression of both genes, suggesting an effect on the photosynthetic function. While organic pollutant effects on marine phytoplankton have been already demonstrated at the cellular level, this is the first field study showing alterations at the molecular level of the photosynthetic function due to organic pollutants.

Towards bioremediation of toxic unresolved complex mixtures of hydrocarbons: identification of bacteria capable of rapid degradation of alkyltetralins

Unresolved complex mixtures (UCMs) of aromatic hydrocarbons are widespread, but often overlooked, environmental contaminants. Since UCMs are generally rather resistant to bacterial degradation, bioremediation of UCM-contaminated sites by bacteria is a challenging goal. Branched chain alkyltetralins are amongst the individual classes of components of aromatic UCMs which have been identified in hydrocarbon-contaminated sediments and a number of synthetic alkyltetralins have proved toxic in laboratory studies. Thus, alkyltetralins should perhaps be amongst the targets for UCM bioremediation strategies. The slow degradation of several alkyltetralins by a microbial consortium has been reported previously; however, the bacteria involved remain unidentified and no single strain capable of alkyltetralin biodegradation has been isolated. The present project therefore aimed to enrich and identify bacterial consortia and single strains of bacteria from a naturally hydrocarbon-contaminated site (Whitley Bay, UK), which were capable of the degradation of two synthetic alkyltetralins (6-cyclohexyltetralin (CHT) and 1-(3’-methylbutyl)-7-cyclohexyltetralin (MBCHT)). Bacteria were enriched from sediment collected from Whitley Bay, UK by culturing with CHT and MBCHT for a period of 4 months. Biodegradation experiments were then established and degradation of model compounds monitored by gas chromatography–mass spectrometry. Internal standards allowed the generation of quantitative data. 16S rRNA gene clone libraries were constructed from individual enrichments to allow assessment of microbial community structure. Selective media containing MBCHT were used to isolate single bacterial strains. These strains were then tested in liquid culture for their ability to degrade MBCHT. The consortia obtained through enrichment culture were able to degrade 87% of CHT and 76% of MBCHT after only 46 days compared with abiotic controls. The 16S ribosomal RNA gene clone libraries of these bacteria were dominated by sequences of Rhodococcus spp. Using selective media, a strain of Rhodococcus was then isolated that was also able to biodegrade 63% of MBCHT in only 21 days. The present report describes the isolation of a single bacterial strain able to degrade the resistant MBCHT. Although significant losses of MBCHT were observed, putative metabolites were not detectable. Rhodococcus sp. have been reported previously to be able to biodegrade a range of hydrocarbon compounds. Due to their environmental persistence and toxicity, aromatic UCMs require bioremediation. The culturing and identification of such bacteria capable of rapid degradation of alkyltetralins may be an important step toward the development of bioremediation strategies for sites contaminated with toxic UCMs.

Analysis of unresolved complex mixtures of hydrocarbons extracted from Late Archean sediments by comprehensive two-dimensional gas chromatography (GC×GC)

Hydrocarbon mixtures too complex to resolve by traditional capillary gas chromatography display gas chromatograms with dramatically rising baselines or “humps” of coeluting compounds that are termed unresolved complex mixtures (UCMs). Because the constituents of UCMs are not ordinarily identified, a large amount of geochemical information is never explored. Gas chromatograms of saturated/unsaturated hydrocarbons extracted from Late Archean argillites and greywackes of the southern Abitibi Province of Ontario, Canada contain UCMs with different appearances or “topologies” relating to the intensity and retention time of the compounds comprising the UCMs. These topologies appear to have some level of stratigraphic organization, such that samples collected at any stratigraphic formation collectively are dominated by UCMs that either elute early- (within a window of C 15–C 20 n-alkanes), early- to mid- (C 15–C 30 n-alkanes), or have a broad UCM that extends through the entire retention time of the sample (from C 15–C 42 n-alkanes). Comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC–MS) was used to resolve the constituents forming these various UCMs. Early- to mid-eluting UCMs are dominated by configurational isomers of alkyl-substituted and non-substituted polycyclic compounds that contain up to six rings. Late eluting UCMs are composed of C 36–C 40 mono-, bi-, and tricyclic archaeal isoprenoid diastereomers. Broad UCMs spanning the retention time of compound elution contain nearly the same compounds observed in the early-, mid-, and late-retention time UCMs. Although the origin of the polycyclic compounds is unclear, the variations in the UCM topology appear to depend on the concentration of initial compound classes that have the potential to become isomerized. Isomerization of these constituents may have resulted from hydrothermal alteration of organic matter.

Temporal trends of hydrocarbons in sediment cores from the Pearl River Estuary and the northern South China Sea

Concentrations and fluxes of unresolved complex mixture of hydrocarbons (UCM) and polycyclic aromatic hydrocarbons (PAHs) were analyzed for two (210)Pb dated sediment cores from the Pearl River Estuary (PRE) and the adjacent northern South China Sea (NSCS). Compound-specific stable carbon isotopic compositions of individual n-alkanes were also measured for identification of the hydrocarbon sources. The historical records of PAHs in the NSCS reflected the economic development in the Pearl River Delta during the 20th century. PAHs in the NSCS predominantly derive from combustion of coal and biomass, whereas PAHs in the PRE are a mixture of petrogenic and pyrogenic in origins. The isotopic profiles reveal that the petrogenic hydrocarbons in the PRE originate predominantly from local spillage/leakage of lube oil and crude oils. The accumulation rates of pyrogenic PAHs have significantly increased, whereas UCM accumulation has slightly declined in the NSCS in the recent three decades.

Chronic sublethal effects associated with branched alkylbenzenes bioaccumulated by mussels

Crude oils are complex mixtures of many thousands of compounds, both resolved and unresolved by conventional gas chromatography (GC). Recent research using comprehensive two-dimensional gas chromatography-time-of-flight-mass-spectrometry (GC x GC-ToF-MS) identified branched alkylbenzenes (BABs) as a major component of some unresolved complex mixtures of hydrocarbons (UCMs) bioaccumulated in the tissues of North Sea mussels, Mytilus edulis, previously found to have poor health status. Here the effect of long-term exposure to low aqueous concentration of BABs and mussels' ability to recover, was determined. Mussels were exposed to 5 microg/L of a complex mixture of C(12-14) BABs for 14 d. Feeding rates and the viability of hemocytes were measured immediately after exposure and again after 5 d depuration. Tissues were extracted, analyzed and alkylbenzenes quantified by both GC-MS and GC x GC-ToF-MS. Mussel extracts from previous acute tests were also reanalyzed and quantified using GC x GC-ToF-MS. Mussels exposed to 5 microg/L BABs for 14 d accumulated 46 to 47 microg/g dry weight alkylbenzenes; this was similar to tissue concentrations of mussels exposed to 41microg/L for 72 h. Feeding rates were significantly reduced (p < or = 0.05) and were dependent upon tissue concentration. Cellular viability was not significantly affected. Following 5 d in clean seawater, the BABs were only partially depurated and feeding rates failed to fully recover. The use of GC x GC-ToF-MS in the present study has shown that mussel tissue concentrations of complex mixtures of alkylbenzenes, and their corresponding effects, are consistent with reported concentrations within UCM-contaminated wild mussel populations with poor health status.

Can Amphipod Behavior Help to Predict Chronic Toxicity of Sediments?

ABSTRACT Amphipods are widely used in both acute and chronic (sub-lethal) sediment tests. Acute sediment tests provide relatively rapid results, but may fail to detect moderately toxic contaminants that are bound to the sediment, whereas chronic life-cycle tests are rarely performed as they are time consuming and expensive. Observations during chronic testing of oil-contaminated sediment suggested that there may be a link between the behavior of the marine amphipod Corophium volutator and reduction in growth rate. Behavior tests were performed with six individual amphipods per treatment using sediment spiked with weathered Forties oil with burrowing time, re-emergence from sediment, and activity prior to burrowing as endpoints. Further behavior tests were used to predict the chronic toxicity of sediments spiked with three crude oils each with a dominant unresolved complex mixture of hydrocarbons (UCM). The effect of sediment type on behavior was also investigated. The results suggested that although the behavior test could not be used alone as a viable alternative to sediment toxicity tests, it could prove useful as an adjunct to acute tests, and help select sediments that deserve further investigation.

Relative hopane content confirming the mineral origin of hydrocarbons contaminating foods and human milk

Hopanes, triterpenoid hydrocarbons formed under geological conditions, were analysed to confirm the mineral origin of the unresolved complex mixtures of hydrocarbons observed in the gas chromatography with flame ionization detection chromatograms of human milk and certain foodstuffs. The ‘relative hopane content’ (RHC) is introduced, i.e. it is the area ratio of the sum of the hopanes and the paraffins in the same segment of the chromatogram. The RHC in various mineral oil products (motor oils, hydraulic oils, lubricating oils, Vaseline) was 3.4%, with a relative standard deviation of 19%. The RHC determined in samples of vegetable oils, mussels and clams as well as of human milk containing an unresolved complex mixture of hydrocarbons was in the same range, confirming that these samples were contaminated by mineral oil material.

Climatic dependence of the organic matter contributions in the north eastern Norwegian Sea over the last 15,000 years

Lipids are used for the evaluation of the different organic matter contributions in the north eastern Norwegian Sea (M23258 site, 75°N, 14°E) over the last 15,000 years. Development of a mass balance model based on the down-core quantification of the C37 alkenones, the odd carbon numbered n-alkanes (Aodd) and the unresolved complex mixture of hydrocarbons (UCM) has allowed three main organic matter inputs involving marine, continental and ancient reworked organic matter to be recognized. The model shows good agreement between measured and reconstructed TOC values. Similarly, a strong parallelism is observed between predicted components such as marine TOC and carbonate content, which was determined independently. Representation of the model results within a time scale based on 15 AMS-14C measurements shows that the main changes in organic matter constituents are coincident with the major climatic events of the last 15,000 years. Thus, the predominance of reworked organic matter is characteristic of Termination Ia (up to 70%), continental organic matter was dominant during the Bølling-Allerød (B-A) and Younger Dryas (YD) periods (about 85%) and a strong increase of marine organic matter occurred in the Holocene (between 50 and 75%). This agreement reflects the main hydrographic changes that determined the deposition of sedimentary materials between 0 and 15 cal ka: ice-rafted detritus from the Barents continental platform, ice-melting waters from the Arctic fluvial system discharging into the Barents Sea and dominance of North Atlantic currents, respectively. In this respect, the high-resolution down-core record resulting from the mass balance and lipid measurements allows for the identification of millennial scale events such as the increase of reworked organic matter at the final retreat of the Barents ice sheet at the end of the deglaciation period (Termination Ib).

The Aegean Sea Oil Spill. 2. Temporal Study of the Hydrocarbons Accumulation in Bivalves

Aliphatic and aromatic hydrocarbons were determined in tissues of mussels (Mytilus edulis), clams (Tapes semidecussata), cockles (Cardium edule), and oysters (Ostrea edulis), collected 3, 6, 9, 12, and 34 months after the Aegean Sea oil spill occurred in the Galicia coast (NW Spain) in December 1992. Petroleum uptake was confirmed by the presence of an unresolved complex mixture of hydrocarbons containing fossil markers, such as triterpanes and saturated and aromatic steranes. These markers were useful in assessing the spatial and temporal evolution of the spilled oil in the area, resulting in the pregnane derivatives particularly enriched in the bivalve tissues. The distribution of parent 3−6-ring polycyclic aromatic hydrocarbons reflected the concurrence of oil residues and combustion products, possibly from the tanker fire. These distributions were depleted in higher ring components with respect to those found in sediments, indicating a lower bioavailability of the pyrogenic components but a longer per...

Evaluation of anthropogenic and biogenic inputs into the western Mediterranean using molecular markers

Aliphatic hydrocarbons (AHs), sterols (ST), and lipid classes were determined in suspended particles collected in the Catalan Sea, northwestern Mediterranean. Principal Component Analysis of the data set revealed a clustering of samples depending on the sources of organic matter, i.e., coastal influenced, open sea and frontal zone. Terrestrial inputs were recognized in particles collected in the surface waters, at the vicinities of river outflow (i.e., Rhône and Ebro), by a predominance of C 29 and C 31 n -alkanes, 24-ethylcholest-5-en-3β-ol (S12), and the anthropogenic 5β(H)-cholestan-3β-ol, coprostanol (S1). Phytoplanktonic molecular markers ( n -C 17 , 27-nor-24-methylcholesta-5,22E-dien-3β-ol, cholesta-5,22-dien-3β-ol and 24-methylcholest-5-en-3β-ol) were widespread but relatively more apparent in the open sea and frontal zones. A similar distribution was observed for lipid classes, with higher concentrations of phospholipids , and an enrichment in free fatty acids in the areas influenced by river discharges. Total sterol, the unresolved complex mixture of hydrocarbons and the pristane–phytane ratio were highest at a persistent frontal zone, possibly reflecting the combination of a higher primary productivity and fossil hydrocarbon absorption on to suspended particles. Moreover, vertical profiles exhibited a subsurface concentration maximum at 20–30 m water depth, concurrently with the chlorophyll.

Gas chromatographic screening of organic compounds in urban aerosols: II. Changes in hydrocarbon composition during storage

Gas chromatographic and gas chromatographic—mass spectrometric analyses of inadequately stored filters and hydrocarbon extracts of urban aerosols have shown the occurrence of microbially mediated transformation processes giving rise to hydrocarbon patterns different from the original composition of the samples. In all cases, a strong decrease in the concentration of the unresolved complex mixture of hydrocarbons is observed. The modifications also involve the formation of mixtures of C 29–C 34 iso- and anteisoalkanes and modal distributions of C 15–C 20 n-alkanes with no even/odd carbon number preference in vials and filters, respectively. These n-alkane distributions may even dominate the chromatographic profiles of the aliphatic hydrocarbon fractions corresponding to long-term stored filters. Decay of the polycyclic aromatic hydrocarbons of lower stability, e.g. 4(H)-cyclopenta[ cd]pyrene and benzo[ a]pyrene, is also observed in the filters. These de novo-produced n-alkane and iso- and anteisoalkane distributions occur at the initial stages of transformation, providing a useful tool for the detection of this type of post-sampling process.

Biodegradation studies of unresolved complex mixtures of hydrocarbons: model UCM hydrocarbons and the aliphatic UCM

An unresolved complex mixture (UCM) of hydrocarbons isolated from a commercially available lubricating oil, and a synthetic mixture of C 25 hydrocarbons were subjected to biodegration by an aerobic bacterium, Pseudomonas fluorescens, for 0–25 days. The rate and extent of biodegration was influenced by molecular structure. Straight chain and monomethyl-alkanes were rapidly degraded in the first 10 days in the approximate order n-C 25>2-methyl->9-methyl-tetracosane. The remaining alkanes were degraded more slowly, initially at a rate comparable to the UCM ( ca 1% day − up to day 14) but thereafter more quickly ( ca 3% day −). The UCM was degraded as a whole, i.e. no reduction in the proportion of resolved vs unresolved alkanes was observed.

Use of oxidative degradation followed by capillary gas chromatography-mass spectrometry and multi-dimensional scaling analysis to fingerprint unresolved complex mixtures of hydrocarbons

Unresolved complex mixtures (UCMS) of hydrocarbons are a common feature of the gas chromatograms of bacterially degraded crude oils, some refined oils ( e.g., lube oils) and of oil-polluted sediment extracts. It is often difficult to identify the original source oil in polluted sediments by existing methods. A study was made of the use of chemical oxidation of ten UCMs to yield gas chromatographically resolvable compounds and analysis of the oxidation products by quantitative gas chromatography-mass spectrometry. The data were then used to calculate inter-sample Euclidean distances. These values were input into a multi-dimensional scaling program which allows similar samples to be clustered. This technique allows UCMs in a number of different sediments to be compared with their likely source oils.

Characterization of unresolved complex mixtures of hydrocarbons from lubricating oil feedstocks

Lubricating oils, particularly those blended from hydrocarbon feedstocks for use as automobile lubricants, are economically important petroleum products. The hydrocarbons of waste lubricating oils are also quantitatively important sources of environmental pollution. However, both the feedstocks and the hydrocarbons found in sediments polluted with waste lube oils are very difficult to characterize by existing analytical methods and little is known, in detail, of their chemical composition. For example, the hydrocarbons often appear as unresolved complex mixtures (UCMs) when examined by techniques which are routinely successfully used to characterize other hydrocarbon mixtures such as crude oils (e.g., gas chromatography (GC) or GC-mass spectroscopy (GC-MS))

Biogeochemistry of organic matter in Lake Geneva: I ? particulate hydrocarbons as biogenic and anthropogenic molecular markers

A study of the biogeochemistry of organic matter in Lake Geneva at a central station (SHL2), was carried out at key periods of the biological cycles from November 1985 to September 1986. The seasonal variability of particulate hydrocarbons was studied in the epilimnion and the hypolimnion, focusing on specific periods such as high phytoplankton productivity and rising herbivorous zooplankton activity (May 1986), clearness of waters (June 1986) and intense mixing of waters (February 1986). Analysis of non-aromatic hydrocarbons (NAH) indicated that their major source is the autochtonous phytoplankton. Year 1986 was characterized by a spring bloom of nanoplankton (chlorophyceae and cryptophyceae) which remained predominant during summer and fall. These biological events were correlated with an increase of biogenic NAH, particulary n-alkane and alkene concentrations; the latter increased by one order of magnitude in May. n-Alkane distributions maximized at n-C17 or n-C29, and the n-C17/n-C29 ratio varied in surface water from 2.8 in May to 0.06 in November of the preceding year, reflecting phytoplankton dominant species. Values of NAH/POC, n-alkanes/POC, alkenes/POC and pristane/phytane ratios underwent seasonal and vertical variations which could be related to grazing and/or settling of particles. NAH, n-alkane and alkene enrichment in hypolimnion particles was interpreted to be a result of zooplankton migrations. A series of 37 monoenes and polyenes having from 15 to 31 carbon atoms, originating from planktonic sources, were recognized in the particulate matter by gas chromatography/mass spectrometry (GC/MS). Their distribution was described in 3 sized particles (> 200 µm, 200-60 µm and < 60 µm, identified as adult zooplankton, young zooplankton and nanoplankton respectively) at two different periods of the biological cycle, May and June 1986. Low level inputs originating from terrestrial higher plants were evident in particles; the value of the Carbon Preference Index (CPI) in the carbon range 23–35 was less than 2.8. In all samples analyzed by GC, an unresolved complex mixture of hydrocarbons (UCM) was present and was interpreted, at least in May, as partly originating from the degradation of organic matter by microorganisms. Typical anthropogenic PAH, such as benzofluoranthene and dibenzo (a) anthracene, were found at a low level (9 and 3 ng l−1 respectively). The absence of hopane-type hydrocarbons, except in November 1985 and in September 1986, and typical combustion PAH associated with particles indicated high temperature pyrolytic contaminants rather than petroleum-derived compounds.

Characterization of unresolved complex mixtures of hydrocarbons in petroleum

ALTHOUGH petroleum is an important energy resource, there is still much to learn about its composition that would be of practical importance in exploration, refining and the identification of materials resulting from oil spills. Chromatography does not resolve (and thus identify) a substantial proportion of even the hydrocarbons in petroleum. These components are often referred to as the unresolved complex mixture (UCM), or 'hump', which is especially pronounced for biodegraded petroleum and certain refined fractions such as lubricating oils1–4. We now describe the use of several methods in parallel to analyse the hydrocarbon hump from crudes, lubricating oils and oil-spill samples. Comparison of our results with those for synthesized alkanes allows us to propose model structures for some of the hydrocarbon components of the hump, and from in vitro studies we conclude that the resistance of many of these compounds to microbial degradation arises partly from their structure.

Bacterial reworking of sedimentary lipids during sample storage

Alterations in the hydrocarbon composition of recent sediments during storage at ambient temperature for short periods of time (1 month) have been observed. These consist in the transformation of the high odd-to-even carbon number predominated C 25C 33 n-alkane distributions into C 22C 30 n-alkanes with no carbon number preference, the generation of an unresolved complex mixture of hydrocarbons eluting between n-C 16 and n-C 22 and the degradation of the hopane components. Aerobic microbial reworking seems to be the process responsible for these changes.

Comparative study on organic constituents in polluted and unpolluted inland aquatic environments—V: Organic carbons and hydrocarbons in sediments

Organic carbons and hydrocarbons were analysed for polluted sediments from Tama River and sludges from night soil and sewage treatment plants in the Tokyo area and unpolluted sediments from river and reservoirs from Chichi-jima Island in the Ogasawara (Bonin) Islands to characterize their features for polluted and unpolluted aquatic environments. In addition the relationships of the features of organic constituents between waters and sediments were given. The contents of n-alkanes (C 14-C 36). squalane and unresolved complex mixture of hydrocarbons (UCMH) for the sediments from Tama River ranged from 16 to 94, 0.86–15 and 250–1100 μ g −1 dry base, which are much higher than those of the sediments from Chichi-jima Island. The major constituents of hydrocarbons in the sediments and sludges from the Tokyo area were mainly odd-carbon numbered n-alkanes and squalane, whereas those of the island were only odd-carbon numbered n-alkanes. Hydrocarbons as carbon (total content × 0.851. as C 20H 42, HCC)/total organic carbon (TOC), HCC/extractable organic carbon with ethyl acetate (EOC), squalane as carbon (SqC)/TOC. SqC/EOC and UCMH/ n-Alkane (C 15-C 33) values for the sediments from Tama River were much higher than those of the sediments from the island, while carbon preference index (CPI H) values for the sediments of Tama River were considerably lower than those of the island. It was thus indicated that HCC/TOC, HCC/EOC, UCMH/ n-Alkane and CPI H values should be the important indicators of hydrocarbon pollution for aquatic environments. In addition SqC/TOC and SqC/EOC ratios are apparently useful measures of urban-industrial activities on aquatic environments. The similarity of the nature of hydrocarbons of sediments and sludges from the Tokyo area indicated that the sewage contributed considerably to urban river sediments. Further it was also indicated that hydrocarbons were concentrated in sedimentary environments, although the features of hydrocarbons in sediments are generally similar to those of waters.

Comparative study on organic constituents in polluted and unpolluted inland aquatic environments-IV Indicators of hydrocarbon pollution for waters

The ratios between organic carbons and hydrocarbon constituents were compared for polluted river waters from the Tokyo area and unpolluted river, brook, reservoir and pond waters from the Ogasawara (Bonin) Islands to derive indicators of hydrocarbon pollution fossil fuels and their products and both combustion products, and industrial products. The hydrocarbons as carbon (HCC)/total organic carbon (TOC). HCC extractable organic carbon with ethyl acetate (EOC), squalane as carbon (SgC),TOC, SqC/EOC, and unresolved complex mixture of hydrocarbons (UCMH) n- Alkane (C 15-C 33) ratios of the waters from the Tokyo area were much higher than those of the waters from the Ogasawara Islands. The values of carbon preference index (CPI 11) for n- alkanes (C 14-C 14) close to unity were found in all the water samples from the Tokyo area. They are considerably lower than those of the water samples from the Ogasawara Islands. These results indicate that the HCC TOC, HCC/EOC UCMH/ n- Alkane and CPI 11 values are the important indicators of hydrocarbon pollution. Further, it was suggested that the SqC/TOC and SqC/EOC ratios are useful indicators of urban-industrial activities on water systems.