Hydrocarbons In Surface Sediments Research Articles

Polycyclic aromatic hydrocarbons in surface sediment from Yangpu Bay, China: Distribution, sources and risk assessment

The study investigated the occurrence of polycyclic aromatic hydrocarbons (PAHs) in the surface sediment from eleven sites in Yangpu Bay, China in December 2013 (winter) and July 2014 (summer). The 16 US EPA priority PAHs were found in the range of 1583.2–5701.7ng/g dry weights with an average of 3134.7±1241.3ng/g in winter and ranged from 2161.8 to 4527.2ng/g with an average of 3016.6±748.0ng/g in summer, respectively. The concentrations of the PAHs tended to be relatively high in comparison with other areas from the literatures. The identification using molecular indices analysis indicated that the PAHs originated mainly from pyrogenic and petrogenic sources in most of the sites. According to principle component analysis–multiple linear regression (PCA/MLR) for their source apportionment, the main sources of PAHs were vehicle emissions, petroleum products and biomass combustion. The risk assessment using international sediments quality guidelines and sediments quality criteria indicated that several PAHs, such as Nap, Flu, Phe, Ace, Acy and BghiP in most of the sites would potentially affect organisms in Yangpu Bay.

Distribution, Sources, and Potential Ecotoxicological Risk of Polycyclic Aromatic Hydrocarbons in Surface Sediments from Bahía Blanca Estuary, Argentina.

Thirty-four surface sediment samples were collected from Bahía Blanca Estuary, Argentina, to evaluate polycyclic aromatic hydrocarbon (PAH) contamination and ecotoxicity risk by applying sediment-quality guidelines (SQGs) and toxic equivalent factors (TEQ). Total concentrations of 17 parent PAHs, including the 16 United States Environmental Protection Agency priority PAHs, were measured using gas chromatography-mass spectrometry, and their levels ranged from 19.7 to 30,054.5ng/g dry weight. The greatest values were found near the urban/industrial core and decreasing as the distance from that site increased. Molecular ratios determined mixed sources of PAHs with a slight imposition of pyrolitic over the petrogenic inputs. The ecotoxicological evaluation, based on the SQG model, showed that some of the individual PAHs were in excess of the effects range low (ERL) and the effects range median's threshold; then, predicted occasional (ERL) and frequent adverse effects over the surrounding biota at the area of study were determined. Total PAH levels were expressed as benzo-a-pyrene TEQ and compared with literature data.

Distribution of polycyclic aromatic hydrocarbons in surface sediments of lower reaches of the Don River (Russia) and their ecotoxicologic assessment by bacterial lux-biosensors.

The lower Don River in the south of the European part of Russia was studied to determine the concentration, spatial distribution, and sources of 19 polycyclic aromatic hydrocarbons (PAHs) in surface sediments. Total PAH concentrations ranged from 14.2 to 529ng/g-dw. Sedimentary PAH concentrations were higher in the delta of the Don River and in the estuaries of rivers Sal and Aksai compared to the main channel of the Don. Analysis of the PAHs sources showed that PAHs came mostly from pyrogenic sources as a result of incomplete combustion of coal. Bioluminescent bacterial sensors were used for ecotoxicological assessment of surface sediments. The surface sediments of all the investigated stations of lower reaches of the Don River were toxic and genotoxic. The maximum concentration of PAHs and the high genotoxicity effect caused by the presence of genotoxicants were found in the surface sediments of the same stations. Significant correlations between the concentrations of individual PAHs in sediments and the genotoxic effect were found. Correlation between genotoxicity of surface sediments and concentration of phenanthrene and benz(k)fluoranthene was the most significant both with and without application of metabolic activation.

Composition, source identification and ecological risk assessment of polycyclic aromatic hydrocarbons in surface sediments of the Subei Grand Canal, China

Polycyclic aromatic hydrocarbons (PAHs) in sediments of the Subei Grand Canal (SGC) are thought to have a significant effect on the water quality of the South to North Water Transfer Project in China. The SGC is in Jiangsu Province and is the northern section of the Beijing-Hangzhou Grand Canal; it is also part of the eastern route of the South to North Water Transfer Project. In the present study, 37 surface sediment samples were collected from the SGC and were analyzed by high performance liquid chromatography (HPLC) for their PAH concentration. The total PAH concentration in surface sediments was moderate, and ranged from 634 to 14,703 ng/g (dry weight), with a mean of 5239 ng/g. There was significant spatial variation in the total PAH concentrations; for example, the mean concentrations in the Xuzhou area, Huaian-Suqian area, and Yangzhou area were 9708, 3872 and 2376 ng/g, respectively. The organic carbon content (9.4–99.6 mg/g) had an important influence on the PAH concentrations in sediment. Analysis using PAH ratios and PCA indicated that the main sources were coal and wood combustion, vehicular and shipping emissions, and coke ovens. An ecological risk assessment based on biological threshold showed that the PAH in surface sediments of the SGC had the potential to cause adverse biological effects to aquatic organisms, and that these effects were more serious around Xuzhou than in the other areas.

Origin, distribution and toxicological potential of polycyclic aromatic hydrocarbons in surface sediments from the Bushehr coast, The Persian Gulf

To evaluate the hazards of polycyclic aromatic hydrocarbons (PAHs) in the Bushehr coastal zones, 12 surface sediments were analyzed. The ∑14PAHs concentrations varied from 371 to 611ngg−1 dw. The primary sources of the observed PAHs were pyrolytic processes, demonstrating the dominance of petroleum-related combustion inputs. The ERL/ERM and TEL/PEL values showed that there was a moderate level of toxicity risk for some PAHs. The toxicological significance of the pollutants was assessed using the toxic equivalency factor (TEF) to calculate both the toxic equivalent for dioxins (TEQTCDD) and the TEQ carcinogenic risks. Dibenz(a,h)anthracene exhibited the highest proportion in the TEQs, ranging from 49% to 56% (TEQcarc) and from 29% to 39% (TEQTCDD) regarding the overall toxicity in the sampled sediments. This result suggests that the ambient dibenz(a,h)anthracene concentration represents the risk posed by PAHs in the sediments. Moreover, using a specific sediment criterion demonstrated the bioaccumulation potential of benzo(a)pyrene for humans in the sampled sediments.

Heterogeneous distribution of polycyclic aromatic hydrocarbons in surface sediments and red mullet along the Spanish Mediterranean coast

The spatial distribution of polycyclic aromatic hydrocarbon (PAH) concentrations was characterised in surface sediments and red mullet from eleven Iberian Mediterranean coastal areas. Mean PAH concentrations ranged from 28 to 1006 and from 3 to 40μgkg−1d.w. in sediment and red mullet muscle, respectively. The highest PAH concentrations in sediments were detected close to main ports and urban nuclei. However, concentrations of PAHs in red mullet showed little correspondence with PAH concentrations of the sediments due to its metabolic capacity. Phenanthrene was the predominant homologue in red mullet, whereas fluoranthene, pyrene and benzo(b)fluoranthene were the most abundant ones in sediments.Significant correlations between PAHs and organic carbon or fine fraction in sediments were only found in some areas. PAH concentrations in sediments were lower than environmental criteria in the majority of cases, except for benzo(g,h,i)perylene in 25% of samples from the Barcelona coastal area and for several homologues close to the port of Sagunto.

Characterization and sources analysis of polycyclic aromatic hydrocarbons in surface sediments in the Yangtze River Estuary

Eighteen polycyclic aromatic hydrocarbons (PAHs), including 16 PAHs selected as priorities for control by the US Environmental Protection Agency, 1-methylnaphthalene and 2-methylnaphthalene, were determined in sediment samples from the Yangtze River Estuary, including the intertidal marshes and the river plume area. Results showed the PAH concentrations in marsh sediments (316–792 ng g−1) were higher than those in the river plume sediment (98–391 ng g−1). Further analysis suggested the PAH concentrations are correlated with total organic carbon (r = 0.71, p < 0.05), as well as water current and industrial activities. However, particle size less affects distribution of PAHs in Yangtze River Estuary. Results also showed a difference in PAHs’ compositions between marsh and river plume sediments: PAHs with two rings were more abundant than other PAHs’ compositions in river plume sediments, while PAHs with 3–4 rings were dominated in marsh sediments. This distribution pattern suggested different contamination sources between marsh and river plume sediments. The diagnostic ratios of PAH isomers and principal component analysis further demonstrated the PAHs in the marsh sediment came from burning biomass or coal, and those from river plume sediments derived from a mixture of petrogenic and pyrolytic source. The concentrations of total PAHs in the sediments from Yangtze River Estuary were relatively low in comparison with other estuaries around the world. And ecological risk assessment also suggested that the PAHs in the Yangtze River Estuary sediments present little ecotoxicological risk. However, a risk assessment for chronic exposure to low PAH concentrations should be performed in a further study.

Potential source apportionment of polycyclic aromatic hydrocarbons in surface sediments from the middle and lower reaches of the Yellow River, China.

In this work, principal component analysis/multiple linear regression (PCA/MLR), positive matrix factorization (PMF), and UNMIX model were employed to apportion potential sources of polycyclic aromatic hydrocarbons (PAHs) in surface sediments from middle and lower reaches of the Yellow River, based on the measured PAHs concentrations in sediments collected from 22 sites in November 2005. The results suggested that pyrogenic sources were major sources of PAHs. Further analysis indicated that source contributions of PAHs compared well among PCA/MLR, PMF, and UNMIX. Vehicles contributed 25.1-36.7 %, coal 34.0-41.6 %, and biomass burning and coke oven 29.2-33.2 % of the total PAHs, respectively. Coal combustion and traffic-related pollution contributed approximately 70 % of anthropogenic PAHs to sediments, which demonstrated that energy consumption was a predominant factor of PAH pollution in middle and lower reaches of the Yellow River. In addition, the distributions of contribution for each identified source category were studied, which showed similar distributed patterns for each source category among the sampling sites.

Polycyclic aromatic hydrocarbons in surface sediments of Binacional Itaipu Lake, Brazil: characteristics, sources and toxicity evaluation

Itaipu Lake, which includes the Itaipu hydroelectric power plant, is one of the largest dams in the world and has a strong relationship with its surroundings. The flooded area has multiple uses such as navigation, recreation, water abstraction for industrial, urban and agricultural irrigation. The lake is located at the frontier between Brazil, Argentina and Paraguay. In this study, superficial sediments collected from nine sampling sites were analysed for grain size, organic matter and 16 priority polycyclic aromatic hydrocarbons (PAHs) using high-performance liquid chromatography (HPLC) with fluorescence detector. The total concentration of PAHs in the dry sediment ranged from 35.21 to 685.37 µg kg−1. Diagnostic ratios showed that the possible source of PAHs in the Itaipu Lake could be pyrolitic and petrogenic. The potential toxicity of sediment of PAHs varied from not detected to 127.70 µg g−1, suggesting that some adverse ecological effects would arise due to PAHs in these sediments.

Occurrence and distribution of organochlorine pesticides and polycyclic aromatic hydrocarbons in surface sediments from Qinghai Lake, northeast Qinghai–Tibet plateau, China

Organochlorine pesticides (OCPs) and polycyclic aromiatic hydrocarbons (PAHs) were analyzed in surface sediment samples collected from Qinghai Lake, the largest lake in China, which is situated in the northeast Qinghai–Tibet plateau at an altitude of 3200m. The concentrations of these pollutants ranged from 0.02 to 1.00ng/g for hexachlorocyclohexanes (HCHs), from not detected to 0.86ng/g for dichlorodiphenyltrichloroethanes (DDTs), from 0.26 to 1.73ng/g for OCPs, and from 366 to 966ng/g for PAHs. The predominance of α-HCH suggests that long-range atmospheric transport is an important source for HCHs. A low α- to γ-HCH ratio (3.87 on average) indicates the possible usage of lindane in the drainage basin. The high percentage of p,p′-DDE and p,p′-DDD and the low percentage of o,p′-DDT indicated significant degradation from previous inputs, and no recent inputs of dicofol derived DDT. Based on the analysis of the component ratios, PAHs were found to be primarily from the combustion of biomass and coal-based fossil fuels. Using the Canadian sediment guidelines, PAHs are of greater ecological concern than OCPs in Qinghai Lake.

Total petroleum hydrocarbons in surface sediments of the Lithuanian coastal area of the Baltic Sea

Operation of large oil import/export terminals and intensive shipping activities together with input of hazardous substances from terrestrial runoff and constantly developing cities makes the Lithuanian part of the Baltic Sea especially sensitive to contamination with oil products. The paper presents an overview of total petroleum hydrocarbons (TPH) distribution in surface sediments at the Lithuanian near shore and within the Klaipėda State Seaport area – transitional marine-lagoon system. The study is based on the results of examination of surface sediment samples carried out in 2010–2012. The variations of TPH content in bottom sediments are explained by differences in grain size and the genesis of the investigated sediments as well as the degree of organic material decomposition. Extreme values obtained in the Klaipėda Strait area indicate presence of additional TPH contamination sources possibly of anthropogenic origin.

Distribution and sources of polycyclic aromatic hydrocarbons in surface sediments of the Hormuz strait, Persian Gulf

The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were determined in the sediment from the Hormuz strait, Persian Gulf. The sum of 16 PAHs (ΣPAH) concentrations varied from 72.17 to 277.77ngg−1 dry weight, with an average value of 131.20±59.29ngg−1 dry weight. An ecological risk assessment of PAHs, indicated that adverse biological effects caused by acenaphthene and acenaphthylene occasionally may take place in the sediment of Hormuz strait. PAH source identification showed that the PAHs in the sediments come from pyrogenic and mixed origin. Based on classification of pollution levels, sediments from Hormuz strait could be considered as low to moderately polluted with PAHs.

Multivariate assessment of polycyclic aromatic hydrocarbons in surface sediments of the Beijiang, a tributary of the Pearl River in Southern China

To estimate the severity of polycyclic aromatic hydrocarbon (PAH) contamination in the upper sediment of the Beijiang River, 42 sediment samples were analyzed for the presence of 16 key PAHs using gas chromatography-mass spectrometry. The concentrations of PAH in the sediment ranged from 44 to 8,921 ng g(-1) dry weight. The four- to six-ring PAHs, contributing >50% to PAHs in 34 of the 42 sites, were the dominant species. Based on a principal component analysis, combined with multivariate linear regression, it became clear that the most important contributors of PAH were fossil fuel combustion (48%), diesel emissions plus oil spillage (33%), and coke combustion (19%). The surface sediments of Beijiang River were grossly contaminated by PAHs mainly derived from combustion.

Levels, composition profiles and sources of polycyclic aromatic hydrocarbons in surface sediments from Nan’ao Island, a representative mariculture base in South China

Levels, composition profiles and sources of 16 polycyclic aromatic hydrocarbons (PAHs) in surface sediments from Nan’ao Island, one of the largest mariculture bases in South China were investigated. The total PAHs concentrations ranged from 265.49 to 951.27ng/g (dry weight) with a mean of 515.90ng/g, and seven possible carcinogenic PAHs accounted for 76.94% of total PAHs. Among various mariculture sections, the highest PAHs level was found in the large seaweed culture; while the lowest concentration was detected in the abandoned culture. The composition of PAHs was characterized by low molecular weight PAHs, and Phe Ant and Pyr were the dominant constituent. PAHs may be mainly originated from petroleum and combustion of biomass and coal. Risk assessments suggested that the probability of adverse effect was lower than 25% and PAHs exposure was moderately carcinogenic.

Source apportionment of polycyclic aromatic hydrocarbons in surface sediment of mud areas in the East China Sea using diagnostic ratios and factor analysis

Polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons (AHs) have been quantified for surface sediments collected from the East China Sea (ECS). Our results showed that relatively high levels of PAHs and AHs occurred in both the inner and outer mud areas, while their concentrations at the control site were much lower. AHs for all samples were dominated by the unresolved complex mixture (UCM). Results from diagnostic ratios revealed that sedimentary PAHs were mainly originated from mixed combustion residues of biomass, coal, and petroleum. Combustion residues of petroleum and oil were responsible for the presence of high AHs concentrations. We also conducted factor analysis (FA) to further characterize the PAH and AH sources. Four factors were identified based on the loading of components and attributed to coal and wood combustion (Factor 1), traffic-related sources (Factor 2), petrogenic source (Factor 3) and natural gas combustion (Factor 4).

Polyhalogenated aromatic hydrocarbons in surface sediments from Three Gorges Reservoir

This study was conducted to investigate the current contamination status of polyhalogenated aromatic hydrocarbons (PHAHs) in sediments from the mainstream and 22 primary tributaries of the Yangtze River in the Three Gorges Reservoir region. To accomplish this, the concentrations of 22 polybrominated biphenyl (PBB) congeners, 27 polybrominated diphenyl ether (PBDE) congeners, and 27 polychlorinated biphenyl (PCB) congeners in sediment samples were measured by GC-MS/MS. The result showed that the observed values of PBBs and PBDEs were 22.41 and 35.24 pg g−1 dw, respectively. PBB1, 31 and 103 were the predominant PBB congeners, while PBDE28, 47, 77 and 99 were the predominant PBDE congeners. PBB209 and BDE209 were detected in >39% of the samples, with geometric means 2.43 and 11.92 pg g−1 dw, respectively. PCBs were found to be the predominant compounds in sediment samples among the three PHAH subfamilies, with a geometric mean of 1,231.11 pg g−1 dw, and PCB8, 18, 28, 52 and 66 were the primary PCB congeners. The measured levels of PHAHs were compared with results recently reported in the literature and their respective sediment quality guidelines recommended by the USEPA. The levels of PHAHs in the present study were generally lower than their respective threshold-effect levels, or were comparable to those reported in relatively uncontaminated freshwater samples from other regions. Taken together, these results suggest that, in the reservoir, toxic biological effects on aquatic biota in response to PHAHs contamination of sediments can be expected to be negligible.

Source apportionment of polycyclic aromatic hydrocarbons in surface sediments of the Bohai Sea, China

A total of 112 surface sediment samples covering virtually the entire Bohai Sea were analyzed for polycyclic aromatic hydrocarbons (PAHs), in order to provide the extensive information of recent occurrence levels, distribution, possible sources, and potential biological risk of these compounds in this area. Surface sediment samples were collected from the Bohai Sea using a stainless steel grab sampler. Sixteen PAHs were determined by a Finnigan TRACE DSQ gas chromatography/mass spectrometry. Diagnostic ratios, cluster analysis, and principal component analysis (PCA) with multivariate linear regression (MLR) were performed to identify and quantitatively apportion the major sources of sedimentary PAHs in the Bohai Sea. Concentrations of total PAHs in the Bohai Sea ranged widely from 97.2 to 300.7 ng/g (mean, 175.7 ± 37.3 ng/g). High concentrations of PAHs were found in the vicinity of Luan River Estuary-Qinhuangdao Harbor, Cao River Estuary-Bohai Sea Center, and north of the Yellow River Estuary. The three-ring PAHs were most abundant, accounting for about 37 ± 5 % of total PAHs. The four-ring and five-ring PAHs were the next dominant ones comprising approximately 29 ± 7 and 23 ± 3 % of total PAHs, respectively. Concentrations of acenaphthylene, acenaphthene, and dibenz[a,h]anthracene are higher than Canadian interim marine sediment quality guideline values at most of the sites in the study area. Contamination levels of PAHs in the Bohai Sea were low in comparison with other coastal sediments in China and developed countries. The distribution pattern of PAHs and source identification implied that PAH contamination in the Bohai Sea mainly originates from petrogenic and pyrogenic sources. Further PCA/MLR analysis suggested that the contributions of spilled oil products (petrogenic), coal combustion, and traffic-related pollution were 39, 38, and 23 %, respectively. Pyrogenic sources (coal combustion and traffic-related pollution) contributed 61 % of anthropogenic PAHs to sediments, which indicates that energy consumption could be a dominant factor in PAH pollution in this area. Acenaphthylene, acenaphthene, and dibenz[a,h]anthracene are the three main species of PAHs with more ecotoxicological concern in the Bohai Sea.

Distribution and characterization of organochlorine pesticides and polycyclic aromatic hydrocarbons in surface sediment from Poyang Lake, China

The concentrations of organochlorine pesticides (OCPs) and 16 priority polycyclic aromatic hydrocarbons (PAHs) were investigated in the sediments from Poyang Lake, the largest freshwater lake in China. The results showed that the total concentrations of four hexachlorocyclohexane (HCH) isomers (α-HCH, β-HCH, γ-HCH, δ-HCH), three dichlorodiphenyltrichloroethane (DDT) homologs and their metabolites (p,p′-DDD, o,p′-DDD, p,p′-DDE, p,p′-DDT, o,p′-DDT, o,p′-DDE), sodium pentachlorophenate and PAHs varied from 0.536±0.330 to 6.937±2.655, 14.421±5.260 to 82.871±31.258, 15.346±6.935 to 48.254±16.836, and 33.0±11.5 to 369.1±138.5μg/kg, respectively. The concentrations of HCH isomers followed the order: γ-HCH>β-HCH>δ-HCH>α-HCH. The most dominant γ-HCH ranged from 0.253±0.155 to 3.465±1.010μg/kg, suggesting a recent input of lindane. p,p′-DDD was the most dominant pollutant of DDTs, with a mean concentration of 31.684±13.530μg/kg. The ratios of (DDE+DDD)/DDT ranged from 75±24 to 360±115, indicating no recent input of DDTs. The PAHs were mainly originated from liquid fossil fuel combustion and leakage, except at Pojiang River estuary, where the pyrogenic source (coal, grass and wood combustion) was dominant. Several PAH metabolites were identified and the possible degradation pathways were proposed.

Ecological risk assessment of parent and halogenated polycyclic aromatic hydrocarbons in surface sediments from an urban river in south China

In the present study, 16 priority polycyclic aromatic hydrocarbons (Σ(16) PAHs), including seven carcinogenic PAHs (Σ(7) PAHs) designated by the U.S. Environmental Protection Agency, in surface sediment from an urban river (Shenzhen, south China) were measured. The concentrations of Σ(16) PAHs and Σ(7) PAHs ranged from 27.92 to 7409 ng/g and 0.53 to 2326 ng/g, respectively. Source appointments indicated that the PAHs in surface sediments were mainly derived from coal combustion (36.6%), oil spills (22.2%), vehicle emission (19.5%), and waste incineration (12.1%). The ecological risks posed by PAHs and several halogenated PAHs in these sediment samples were assessed using two redefined guidelines incorporating the toxic equivalency quotients (TEQs) of individual PAH congeners: (1) TEQs effect range-low, and (2) TEQs effect range-median. The authors' results suggested that the PAHs they measured in most of the sediments in this urban river would not cause acute biological effects. On the contrary, the ecological risk posed by some halogenated PAHs was much higher than that of their corresponding parent PAHs. Finally, the relationships between PAH levels and catchment urbanization processes were examined. The results indicated that rapid urbanization has led to an obvious increase in PAH contamination in surface sediments.

Source apportionment of sediment-associated aliphatic hydrocarbon in a eutrophicated shallow lake, China

Chaohu Lake, one of the most eutrophicated lakes in China, has been suffering from long-term outside pollution, urban sewage, river outflows, and agricultural runoff which expectedly have been the main contributors of hydrocarbons. However, the contributions from these various sources have not been specified. The present study is aimed at identifying the potential sources of hydrocarbons in surface sediment around the whole lake and assessing the relative contributions using principal components analysis-multiple linear regression (PCA-MLR). Sixty-one surface sediments covering the whole Chaohu Lake and three main estuaries of inflowing rivers were collected, dried, extracted, and analyzed for 27 normal alkanes (n-alkanes, from C(12) to C(38), defined Σ(27)AH) and unresolved complex mixture (UCM) by GC/MS. Diagnostic ratios and PCA-MLR were utilized to apportion their sources. The concentrations of Σ(27)AH and UCM ranged from 434 to 3,870ng/g and 11.9 to 325μg/g dry weight, respectively, for all samples. The concentrations of Σ(27)AH in western region and estuary of Nanfei River were slightly higher but without statistical significance than those from eastern region and estuaries of Yuxi River and Hangbu River. The concentration of UCM from western region was significantly higher than that obtained from eastern region. These results reflect the importance of input of urban runoff by Nanfei River and serious eutrophication in western region. Aliphatic hydrocarbons in Chaohu Lake were mainly derived from high plant wax with mixed sources of phytoplankton and petroleum. Weak microbial decomposition of n-alkanes would be expected to occur from the low ratios of isoprenoid hydrocarbons pristine (pri) and phytane (phy) to n-C(17) and n-C(18), respectively. Higher plant, fossil combustion, petroleum residue, and phytoplankton were proposed as the main origines of aliphatic hydrocarbons by PCA while the contributions of individual n-alkane homologues, pri and phy from the identified sources (31% from higher plant, 30% from fossil combustion, 26% from petroleum, and 19% from phytoplankton) were well predicted using MLR. The distribution profile and corresponding diagnostic ratios of normal alkanes show the promising potential as a useful proxy for estimating the source and loading of pollutants in Chaohu Lake.