Petrogenic Inputs Research Articles

Distribution and sources of polycyclic aromatic hydrocarbons in the surface water of Taizi River, Northeast of China

Spatial and seasonal distribution and sources of 16 polycyclic aromatic hydrocarbons (PAHs), identified as priority pollutants by the US Environmental Protection Agency, were investigated in the surface water of the Taizi River in Liaoning Province, northeast of China. Samples were collected from the mainstream, and tributaries of the Taizi River in dry, wet, and normal seasons. Five important industrial point sources were also monitored. The total PAH concentrations ranged from 454.5 to 1,379.7ngl(-1) in the dry season, 1,801.6 to 5,868.9ngl(-1) in the wet season, and 367.0 to 5,794.5ngl(-1) in the normal season. The total PAH concentrations were significantly increased in the order of wet season > normal season > dry season. The profile of PAHs in the surface water samples was dominated by low molecular weight PAHs particularly with two- and three-ring components in the three seasons, suggesting that the PAHs were from a relatively recent local source. Source identification inferred that the PAHs in the surface water of the Taizi River came from both petrogenic inputs and pyrogenic sources.

N-Alkanes in surficial sediments of Visakhapatnam harbour, east coast of India

Surface sediments collected from 19 stations along Visakhapatnam harbour were analysed for organic carbon (OC), δ 13 Coc, total lipids (TL), total hydrocarbon (THC), n-alkane concentration and composition. OC, δ 13 Coc, TL and THC ranged from 0.6% to 7.6%, −29.3 to −23.8, 300 to 14,948 μ gg −1 dw, and 0.2 to 2,277 μ gg −1 dw, respectively. Predominance of even carbon numbers n-alkanes C12–C21 with carbon preference index (CPI) of <1 suggests major microbial influence. Fair abundance of odd carbon number n-alkanes in the range of C15–C22 and C23–C33 indicates some input from phytoplankton and terrestrial sources, respectively. Petrogenic input was evident from the presence of hopanes and steranes. The data suggest that organic matter (OM) sources varied spatially and were mostly derived from mixed source.

Composition and source identification of polycyclic aromatic hydrocarbons in mangrove sediments of Peninsular Malaysia: indication of anthropogenic input

This is a comprehensive study of the composition, origin and sources of specific polycyclic aromatic hydrocarbons (PAHs) in sediments of mangrove estuary in the western part of Peninsular Malaysia. Mangrove sediments were analyzed for 17 PAHs by gas chromatography–mass spectrometry. Total PAH concentrations in the sediments ranged from 20 to 112 ng/g on a dry-weight basis. High molecular weight PAHs were abundant in the sediments. Parent PAH ratios revealed that pyrogenic input has important contribution to the sedimentary PAHs. Ratios of alkylated PAHs indicate that the sedimentary PAHs were influenced by petrogenic PAHs, which implies that petrogenic input has contribution to the sedimentary PAHs but that it is not a major factor in distribution of PAHs within the estuary. Combustion-derived PAHs show a positive and very strong correlation with total PAHs (R 2 = 0.926, p < 0.05). Total methylphenanthrenes show very weak correlation with total PAHs (R 2 = 0.0928, p < 0.05). The PAH concentrations were found to increase with distance from the upstream of the estuary to the coastal area of the Straits of Malacca. For the assessment of sediment contamination using biological thresholds, none of the individual studied PAH compounds exceeded the values of the effect range low–effect range median guideline and the threshold effects level–probable effects level guideline. This study demonstrates that the sediments of the mangrove ecosystem facing the Straits of Malacca and Sumatra are influenced by anthropogenic PAH inputs as a result of human activities such as biomass burning, vehicle emissions and boating activities.

Persistent toxic substances in surface water of Todos Os Santos Bay, Brazil

Persistent toxic substances (PTSs) such as polycyclic aromatic hydrocarbons (PAHs) are of great concern due to their persistence, bioaccumulation and toxic effects. In this work, 14 PAHs included in the US Environmental Protection Agency’s (EPA) priority pollutant list were analysed using gas chromatography–mass spectrometry (GC–MS). Surface water sampling was undertaken in Todos os Santos Bay, northern Brazil. Total PAH concentrations varied from 0.0029 to 0.1079 ng/L in surface waters (main rivers, tributaries, etc.) with mean value of 0.0344 ng/L. Such concentrations can be taken as background values for the studied region and show that PAHs are within or lower than levels reported in certain other areas. The PAH profiles were dominated by high molecular weight PAHs (four- and five-ring components) in surface water samples. It indicated that PAHs in surface water have its origin from oil or sewage contamination (petrogenic input). The collected data, based on indices among phenanthrene versus anthracene, showed that petrogenic input was predominant at almost all the stations investigated. Principal component analysis (PCA), using a correlation matrix, revealed the latent relationships among all the surface water stations investigated and confirmed our analytical results.

Petroleum pollution in mangrove forests sediments from Qeshm Island and Khamir Port—Persian Gulf, Iran

The concentrations of total polycyclic aromatic hydrocarbons (PAHs) and 22 individual PAH compounds in 42 surface sediments collected from the mangrove forest of Qeshm Island and Khamir Port (Persian Gulf) were analyzed. PAHs concentrations ranged from 259 to 5,376 ng g(-1) dry weight with mean and median values of 1,585 and 1,146 ng g(-1), respectively. The mangrove sediments had higher percentages of lower molecular weight PAHs and the PAH profiles were dominated by naphthalene. Ratio values of specific PAH compounds were calculated to evaluate the possible source of PAH contamination. This ratios suggesting that the mangrove sediments have a petrogenic input of PAHs. Sediment quality guidelines were conducted to assess the toxicity of PAH compounds. The levels of total PAHs at all of stations except one station, namely Q6, were below the effects range low. Also, concentrations of naphthalene in some stations exceeded the effects range median.

Distribution and sources of aliphatic hydrocarbons in surface sediments of Sergipe River estuarine system

The assessment of aliphatic hydrocarbons was performed in the Sergipe River estuarine system, northeastern Brazil. Aliphatic hydrocarbons concentration ranged from 9.9ugg−1 up to 30.8ugg−1 of dry sediment. The carbon preference index (CPI, based on nC24 to nC34 range), indicated predominance of petrogenic input in two of the sites analyzed (P4 and P5). The unresolved complex mixture (UCM) was found to be present in seven of the nine sites sampled (except for P4 and P5). Overall, the results of this work suggest that there is a mix of organic matter sources to the sediment. Although the coast of Sergipe has an intense off shore petroleum exploration and the Sergipe River crosses the entire city of Aracaju, the capital city of Sergipe, non-significant anthropogenic fingerprint was assessed.

Spatial distribution and seasonal variation of polycyclic aromatic hydrocarbons (PAHs) contaminations in surface water from the Hun River, Northeast China

The objectives of this study were to investigate the levels, dispersion patterns, seasonal variation, and sources of 16 priority polycyclic aromatic hydrocarbons (16 EPA-PAHs) in the Hun River of Liaoning Province, China. Samples of surface water were collected from upstream to downstream locations, and also from the main tributaries of the Hun River in dry period, flood period, and level period, respectively. After appropriate preparation, all samples were analyzed for 16 EPA-PAHs. Total PAHs concentrations varied from 124.55 to 439.27 ng l(-1) in surface water in dry period, 1,615.75 to 5,270.04 ng l(-1) in flood period, and 2,247.42 to 7,767.9 ng l(-1) in level period. The 16 EPA-PAHs concentrations were significantly increased in the order of level period > flood period > dry period. The composition pattern of PAHs in surface water was dominated by low molecular weight PAHs, in particular two- to three-ring PAHs. In addition, two-ring PAH accounted for 39.33 to 88.27 % of the total PAHs in level period. Low molecular weight PAHs predomination together with higher levels of PAHs in flood and level period suggested a relatively recent local source of PAHs. Special PAHs ratios such as phenanthrene/anthracene and fluoranthene/pyrene indicated that under dry weather season conditions, the PAHs found in surface water were primarily from petrogenic source, while under wet weather season conditions they were from mixed source of both petrogenic inputs and combustion sources. The comparison of PAHs contamination among different types of areas in China suggested that atmospheric depositions might be the most important approaches of PAHs into water system. Although the Hun River exists low PAHs ecological risk now, potential toxic effects will be existed in the future especially in flood and level period.

Distribution, source identification, and historical trends of organic micropollutants in coastal sediment in Jakarta Bay, Indonesia

We determined concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), linear alkylbenzenes (LABs), and hopanes in coastal sediments collected from Jakarta Bay and Tokyo Bay. PAH concentrations in sediments from Jakarta Bay (257–1511ng/g-dry) were lower than or comparable to those from Tokyo Bay (1372–1615ng/g-dry). Ratios of alkyl-PAHs to parent PAHs showed a greater contribution of petrogenic inputs in Jakarta Bay than in Tokyo Bay. This difference is consistent with the higher ratio of hopanes to PAHs in Jakarta Bay. LAB concentrations in Jakarta Bay (geometric mean, 1400ng/g-dry) were higher than those in Tokyo Bay (661ng/g-dry). The internal to external (I/E) ratios of LABs in Jakarta Bay (0.92–2.88) were lower than those in Tokyo Bay (2.8–4.8), indicating that Jakarta Bay receives untreated or poorly treated sewage. Significant amounts of tetrapropylene-based alkylbenzenes were detected in several locations in Jakarta Bay, suggesting current usage of the non-degradable surfactants alkylbenzene sulfonates that are banned in many countries. The PCB concentration in Jakarta Bay was 1 order of magnitude lower than in Tokyo Bay, suggesting minimal usage of PCBs in industrial or commercial products in Jakarta. Analyses of a sediment core indicate increasing inputs of PAHs, hopanes, and LABs into Jakarta Bay during recent decades.

Source identification of petroleum hydrocarbons in soil and sediments from Iguaçu River Watershed, Paraná, Brazil using the CHEMSIC method (CHEMometric analysis of Selected Ion Chromatograms)

A chemometric method based on principal component analysis (PCA) of pre-processed and combined sections of selected ion chromatograms (SICs) is used to characterise the hydrocarbon profiles in soil and sediment from Araucária, Guajuvira, General Lúcio and Balsa Nova Municipalities (Iguaçu River Watershed, Paraná, Brazil) and to indicate the main sources of hydrocarbon pollution. The study includes 38 SICs of polycyclic aromatic compounds (PACs) and four of petroleum biomarkers in two separate analyses. The most contaminated samples are inside the Presidente Getúlio Vargas Refinery area. These samples represent a petrogenic pattern and different weathering degrees. Samples from outside the refinery area are either less or not contaminated, or contain mixtures of diagenetic, pyrogenic and petrogenic inputs where different proportions predominate. The locations farthest away from industrial activity (Balsa Nova) contains the lowest levels of PAC contamination. There are no evidences to conclude positive matches between the samples from outside the refinery area and the Cusiana spilled oil.

Sources and distribution of aliphatic and polyaromatic hydrocarbons in coastal sediments from the Ushuaia Bay (Tierra del Fuego, Patagonia, Argentina)

The environmental quality of Ushuaia Bay, located at the southernmost tip of South America, is affected by the anthropogenic pressure of Ushuaia city. In this study, levels and sources of hydrocarbons in coastal sediments were assessed. Aliphatic hydrocarbon fractions ranged between 5.5 and 1185.3 μg/g dry weight and PAHs from not detected to 360 ng/g. Aliphatic diagnostic indices, the nalkanes homologous series occurrence, Aliphatic Unresolved Complex Mixtures (AliUCMs), and pristane and phytane isoprenoids indicated a petrogenic input. Some sites showed biogenic features masked by the anthropogenic signature. Particularly in port areas biodegradation processes were evident. PAH ratios showed a mixture of petrogenic and pyrogenic sources. Aliphatic and aromatic UCMs were strongly correlated, reflecting chronic pollution. Three areas were distinguished inside the bay: (1) east, with low hydrocarbons impact; (2) central, where hydrocarbons accumulation was related to source proximity and sediment characteristics; (3) south-west, where sediment characteristics and current circulation favour hydrocarbons accumulation.

Evaluation of Soil Contamination by Polycyclic Aromatic Hydrocarbons in Gipuzkoa (Northern Spain)

Representative polycyclic aromatic hydrocarbons (PAHs) of low-medium molecular weight were determined using headspace solid-phase microextraction and gas chromatography with a flame ionization detector (HS-SPME-GC-FID) in ten surface soil samples from Gipuzkoa (Northern Spain). The sum of the PAHs ranged from 0.21 to 136.26 mg kg−1. Pyrene and chrysene were the most abundant detected PAHs with an average concentration around 3.1 mg kg−1. Pearson's correlation and PAH isomer ratios were applied to study the different origins of contamination. The results indicated that the PAH contamination in the studied area was a mixed pattern of pyrolytic and petrogenic inputs. Multivariate exploratory techniques, principal component analysis (PCA), and cluster analysis (CA) were also applied corroborating the PAH compounds patterns in the soils.

Polycyclic Aromatic Hydrocarbons in Seawater, Sediment, and Rock Oyster Saccostrea cucullata from the Northern Part of the Persian Gulf (Bushehr Province)

The concentration of polycyclic aromatic hydrocarbons (PAHs) was determined in seawater, sediment, and Rock oyster Saccostrea cucullata collected from four sampling sites in the inter-tidal areas of Bushehr province. The total concentrations of 14 PAHs varied from 1.5 to 3.6 ng/L in seawater, 41.7 to 227.5 ng/g dry weight in surface sediment, and 126 to 226.1 ng/g dry weight in oyster tissue. In comparing PAH concentrations among the three matrices in Bushehr province, data showed that the pattern of individual PAHs in seawater, oyster, and sediment were different. The oysters tended to accumulate the lower molecular weight and the more water-soluble PAHs. Sediment samples were distinguished from the sea water and oyster samples by the presence of high molecular weight PAHs, especially six-ring PAHs. Three- and four-ring PAHs were the most abundant compounds among the 14 PAHs investigated in surface seawater, sediment, and oyster samples. As expected, differences in octanol/water partition coefficient among individual PAHs and the greater persistence of the higher molecular weight PAHs contributed to the accumulation patterns in oyster and sediment. The results of the study suggested that the main sources of PAHs in the seawater and sediment in the region were mixed pyrolitic and petrogenic inputs.

Sources and distribution of aliphatic and polycyclic aromatic hydrocarbons in Yellow River Delta Nature Reserve, China

Sediment samples collected from the Core Area, Experimental Area and Buffer Area of Yellow River Delta National Nature Reserve (YRDNNR), China, were analyzed by GC-MS in order to determine the degree of hydrocarbon contamination, and identify the sources of aliphatic hydrocarbons and PAHs. The total petroleum hydrocarbon contents of sediments were relatively low or moderate compared to world-wide locations reported to be chronically contaminated by oil. On the whole, the degree of petroleum contamination in the Core Area and Buffer Area in YRDNNR is weaker than that of the Experimental Area. The potential ecosystem risk assessment indicated that PAHs will not cause immediate adverse biological effects in the YRDNNR. Besides oil-related hydrocarbon inputs in this region, aliphatic hydrocarbon analysis showed the presence of hydrocarbons of terrestrial origin at some sampling sites, characterized by high CPI values. Based on PAH ratios and principal component analysis, pyrolytic input may be a major source of PAHs in YRDNNR sediment, while petrogenic inputs were more apparent at some sites in the Experimental Area due to oil exploration in the Shengli Oilfield. (C) 2011 Elsevier Ltd. All rights reserved.

Distribution and sources of aliphatic and polycyclic aromatic hydrocarbons in suspended particulate matter in water from two Brazilian estuarine systems

The levels of selected organic markers, including 17 polycyclic aromatic hydrocarbons (PAHs), 16 of which are classified as priority pollutants by the US-EPA and perylene, aliphatic hydrocarbons (total and linear alkanes) and petroleum biomarkers (hopanes and steranes), were measured in suspended particulate matter (SPM) of the Mundaú–Manguaba estuarine-lagoon system (MMELS) in northeastern Brazil and the Paraíba do Sul River (PSR) estuary in southeastern Brazil, both of which are affected by sugarcane agriculture and urbanization. A total of 33 surface water samples of SPM were collected (22 from the MMELS and 11 from the PSR). The ∑16PAH ranged from 221 to 1243 ng g −1 in the MMELS and from 228 to 1814 ng g −1 in the PSR. Hopane and sterane concentrations in the PSR were higher than in the MMELS due to the input from petrogenic sources in PSR. The contributions of higher plants were also observed by n-alkane analyses. The PAH isomeric ratios indicated that the SPM from MMELS showed characteristics of combustion from biomass or petroleum and PSR was associated to petrogenic input, either from combustion or from unburned petroleum. Three sampling sites located near to the sugarcane plant and mouth of the rivers showed higher PAH concentrations and may largely be considered as highly contaminated. However, levels of n-alkanes and petroleum biomarkers in both study areas were relatively low.

Distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of some Italian lagoons exploited for aquaculture and fishing activities

The concentrations of 16 PAHs in surface sediments collected from four Italian lagoons, exploited for aquaculture and fishing activities, during the period 2004–2007, were analysed. Some molecular ratios and Pearson correlations were used in order to estimate the origin of the pollution and similar transport of PAH sources. Principal Component Analysis (PCA) and Cluster Analysis were used in order to highlight dissimilarities among sampling sites. Concentrations of total 16 PAHs varied significantly among the lagoons as well as within the same basin. Sediments of Orbetello lagoon showed the highest level of contamination (mean of 98.78 ng g−1), followed by that in Santa Giusta (48.15 ng g−1), Lesina (31.06 ng g−1) and Varano (25.19 ng g−1). These results were linked to the greater industrialisation and urbanisation of the catchment area of both Orbetello and Santa Giusta compared with Lesina and Varano. A considerable predominance of 4-rings PAHs was observed for Lesina (52%,), Varano (77%), Orbetello (50%) and Santa Giusta (57%) and Pyrene was the dominant compound. On the other hand, phenanthrene is the dominant compound of low molecular weight contaminants for all the studied lagoons. A meaningful pyrolytic contribution to pollution was found in the sediments of Lesina lagoon, dominated by benzo[a]pyrene (7.27 ng g−1) and benz[a]anthracene (4.14 ng g−1), due to intensive traffic. For Varano, an evident petrogenic contamination was observed along the western area, due probably to accidental oil spillage. All 16 PAHs were found to be correlated in Orbetello and Santa Giusta lagoons and the compounds present in Santa Giusta sediments, near the urban centre, were shown to be mainly of pyrolytic origin. A much more complex situation was observed in Orbetello, where a mixed pattern of pyrolytic and petrogenic inputs was observed.

Assessment on the distribution and partitioning characteristics of polycyclic aromatic hydrocarbons (PAHs) in Lake Baiyangdian, a shallow freshwater lake in China

The characteristics of polycyclic aromatic hydrocarbons (PAHs) in water, suspended particulate matter (SPM), sediments, and hydrophytes from Lake Baiyangdian, a shallow freshwater lake in China were studied. The low-molecular-weight PAHs (2-3 ring PAHs) predominated (61.2 to 84.5%) in all samples. Principal component analysis (PCA) of individual PAHs and the ratios of selected PAHs showed that the PAHs in the lake were mainly petrogenic inputs. The solid-liquid distribution coefficient (K(d)) in the water phase was much higher than the bioconcentration factor (BCF), and the leaf concentration factor (LCF) was higher than the root concentration factor (RCF) and stem concentration factor (SCF) in plant-sediment phase. Good linear log/log relationships were observed between the equilibrium partitioning coefficient (K(oc)) and the octanol-water partitioning coefficient (K(ow)), between RCF and K(ow), and between LCF and the octanol-air partitioning coefficient (K(oa)). These results indicated that PAHs accumulated more easily in SPM than in submerged aquatic plants, and some low-molecular-weight PAHs could accumulate and be translocated in the lake's media. Media characteristics, contamination sources, and physicochemical properties all affect the partitioning of PAHs among water, SPM, sediments, and hydrophytes.

Characteristics of petroleum hydrocarbons in surficial sediments from the Songhuajiang River (China): spatial and temporal trends

This paper presents the spatial and temporal characteristics of petroleum hydrocarbons (PH) in surficial sediments from the Songhuajiang River using the method of petroleum chemical fingerprinting. Twenty-four surface sediment samples were collected at 17 sites along the river from upstream to downstream in flood season (August 2005) and icebound season (December 2005) and were analyzed for PH including n-alkanes (C(16)-C(33)), isoprenoid alkanes (pristane and phytane), and unresolved complex mixture (UCM). The concentration of PH varied from 22.64 to 91.45 μg g( -1) dry sediment. n-alkanes with a carbon number from 16 to 33 were detected in all samples, and the UCM was the dominant composition for PH. The variability of the PH concentration was mostly influenced by external conditions, such as seasonal change and industrial area position, as well as internal sediment physicochemical properties, such as organic carbon and grain size. The concentration of hydrocarbons is higher in flood season than in icebound season and is higher upstream than downstream. The diagnostic ratios of specific hydrocarbons showed that the PH pollution comes from a combination of biogenic and petrogenic sources, and petrogenic input is dominant in icebound season relative to flood season. It also indicates that there is a clear terrigenous input of n-alkanes in flood season. Principal components analysis was used to study the composition and characteristics of PH in Songhuajiang River sediments and to assess the spatial and temporal distribution of their natural and anthropogenic sources.

Impacts of pollution derived from ship wrecks on the marine environment on the basis of s/s “ Stuttgart” (Polish coast, Europe)

In 1943 the German hospital ship s/s Stuttgart ( Lazaretschiff “C”) was sunk close to the port of Gdynia (Gulf of Gdańsk — Polish coast). This and other actions (undertaken after the war to remove the wreck) led to pollution of the sea bottom with oil derivatives. During our studies (2009) 11 surface sediment and water samples were collected as well as sediment core samples at 4 locations in order to determine the concentration levels of priority pollutants belonging to polycyclic aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB). The concentrations of 16 PAH and 7 PCB were analysed with GC-MS. ΣPAH varied between 11.54 ± 0.39 and 206.7 ± 6.5 mg/kg dry weight in the surface sediments, and from 0.686 ± 0.026 to 1291 ± 53 mg/kg dry weight in the core samples. Contamination in the core samples collected may reach a depth of at least 230–240 cm (deepest sample studied). The PAH-group profiles in all surface sediment samples suggest a pyrolytic source of PAH, while the results obtained for core samples indicate a mixed pattern of pyrolytic and petrogenic inputs of PAH. Results obtained may suggest also that fuel residues being present at sea bottom is not crude oil derived but results from coal processing (synthetic fuel). The sum of PCB in surface sediments ranged from 0.761 ± 0.068 to 6.82 ± 0.28 μg/kg dry weight (except for sampling point W2, where ΣPCB was 108.8 ± 4.4 μg/kg dry weight). The strong correlation between PAH and PCB levels, and the fact that PCB are present only in the surface sediments, suggest that the compounds in these sediments got there as a result of emission from urban areas, entering the aquatic environment via atmospheric deposition. PCB levels in the sediment core samples were generally very low and in most cases did not exceed the method quantification limit.

Distribution and sources of polycyclic aromatic hydrocarbons in the aquatic environment: a multivariate analysis

Fourteen polycyclic aromatic hydrocarbons (PAHs) included in the US Environmental Protection Agency's (EPA) priority pollutant list were analyzed using gas chromatography-mass spectrometry (GC--MS). Surface water sampling was undertaken in the Paraguaçu Estuary (Bahia), northern Brazil. Total PAH concentrations varied from 0.0029 to 0.1079 ng/L in the surface waters (main rivers, tributaries) with a mean value of 0.0344 ng/L. Such concentrations can be taken as background values for the studied region. The PAH profiles were dominated by low molecular weight PAHs (two- and three-ring components) in surface water samples. It indicated that PAHs in surface water may have its origin from oil or sewage contamination (petrogenic input). The collected data showed that petrogenic input was predominant at almost all the stations investigated. To discriminate pattern differences and similarities among the samples, a principal component analysis (PCA) was performed using a correlation matrix. PCA revealed the latent relationships among all the surface water from the investigated stations.

Pollution source evaluation using petroleum and aliphatic hydrocarbons in surface sediments from two Brazilian estuarine systems

The levels of aliphatic hydrocarbons, including petroleum biomarkers (hopanes and steranes) were measured in surface sediments from two Brazilian estuarine systems affected by sugar cane monoculture and urbanization in order to identify their sources. The total aliphatic hydrocarbon fraction (TAH) concentration in the sediments ranged from 0.39 to 43.83 μg g −1 in the Mundaú–Manguaba estuarine-lagoon system and from 6.40 to 94.27 μg g −1 in the Paraiba do Sul River estuary. The levels of TAH in both study areas are relatively low. The carbon preference index (CPI) calculated for the C 23–C 34 range indicates that n-alkanes are mainly inherited from cuticular waxes of higher plants. However, the presence of hopanes and steranes indicates petrogenic input. The low values for the hopanes/ n-alkanes (Hop/ n-alk) and unresolved complex mixture (UCM)/ n-alk ratios indicate that the pollution is diluted with natural input.