Spatial and temporal distribution of polycyclic aromatic hydrocarbons (PAHs) in sediments of the Nansi Lake, China

Polycyclic aromatic hydrocarbons (PAHs) were measured in surface sediments and dated core sediments from the Nansi Lake of China to investigate the spatial and temporal distribution characteristics. The concentrations of 16 kinds priority PAH compounds were determined by GC-MS method. And ²¹⁰Pb isotope dating method was used to determine the chronological age of the sediment as well as the deposition rate. The results indicated that the total PAHs concentration ranges in surface and core sediment samples were 160 ~32,600 and 137 ~ 693 ng/g (dry wt.), respectively. The sediment rate and the average mass sedimentation were calculated to be 0.330 cm·year^???1 and 0.237 g·cm^???2·yr^???1 and the sediment time of the collected core sample ranged from 1899 to 2000. The peak of PAH concentrations came at recent years. The source analysis showed PAHs mainly came from the contamination of low temperature pyrogenic processes, such as coal combustion. The PAHs concentrations were lower than ERL and LEL values for most collected samples. However, in several surface sediment samples especially in estuary sites, the PAHs concentrations were not only higher than ERL and LEL values, but also higher than ERM values.     

Environmental assessment of polycyclic aromatic hydrocarbons in the surface sediments of a remote region on the eastern coast,Taiwan

Surface sediment samples were collected in He-Ping Harbor and the nearby He-Ping Estuary from 2005 to 2006 to examine spatial and temporal variability in polycyclic aromatic hydrocarbon (PAH) concentrations. The sum of the 16 USEPA priority pollutant PAHs varied from 8 to 312 ng/g dry weight, which was relatively low compared to values obtained from other studies in the world. Regarding temporal changes in the PAH profile, total PAH concentrations in the wet season were lower than during the dry season in He-Ping Harbor. However, the concentration of PAHs exhibited no significant difference in the four seasons in the He-Ping Estuary. PAH concentrations in He-Ping Harbor were higher than those in the He-Ping Estuary. In comparison with sediment quality guidelines, PAH concentrations of sediments in this study were lower than those outlined in the criteria, which suggests no evident adverse biological effects due to PAHs around the He-Ping coast. Ratios of specific PAH compounds calculated to assess the possible sources of PAHs reflect that PAHs in He-Ping Harbor may mainly be from pyrogenic coal combustion.     

Polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the Bizerte Lagoon,Tunisia: levels,sources, and toxicological significance

To assess the status of polycyclic aromatic hydrocarbon (PAH) contamination in sediments from the Bizerte Lagoon (northern Tunisia), 18 surface sediment samples were collected in March 2011 and analyzed for 14 US Environmental Protection Agency priority PAHs by high-performance liquid chromatography. The total concentrations of the 14 PAHs (ΣPAHs) ranged from 16.9 to 394.1 ng g^?1 dry weight (dw) with a mean concentration of 85.5 ng g^?1 dw. Compared with other lagoons, coasts, and bays in the world, the concentrations of PAHs in surface sediments of the Bizerte Lagoon are low to moderate. The PAHs’ composition pattern was dominated by the presence of four-ring PAHs (45.8 %) followed by five-ring (26.8 %) and three-ring PAHs (12.7 %). The PAH source analysis suggested that the main origin of PAHs in the sediments of the lagoon was mainly from pyrolytic sources. According to the numerical effect-based sediment quality guidelines of the USA, the levels of PAHs in the Bizerte Lagoon should not exert adverse biological effects. The total benzo[a]pyrene toxicity equivalent values calculated for the samples varied from 3.1 to 53.7 ng g^?1 dw with an average of 10.6 ng g^?1 dw.     

Measurement of organic contaminants and biological effects in Scottish waters between 1999 and 2005

Concentrations of organic contaminants were determined in sediment and fish collected annually at six sites around Scotland between 1999 and 2005, as part of the UK National Marine Monitoring Programme. Polycyclic aromatic hydrocarbons (PAHs) and chlorobiphenyls (CBs) were measured in sediment, while CBs and ethoxyresorufin-O-deethylase (EROD) activities were measured in the fish. Highest PAH concentrations in sediment were found at sites where higher coastal influences would be expected (e.g., Clyde and Solway) and four of the six sites gave PAH concentrations above OSPAR background assessment concentrations (BACs). A significant downward trend in the median total PAH concentrations, normalised to total organic carbon (TOC), was found at one of the six sites (Minches). The PAH profiles at all sites were consistent over the 6 year period, indicating that the sites are relatively stable and PAH sources are not changing. There was an indication of a greater petrogenic input on the west coast, with sediment from the Clyde, Solway and Minches having a greater proportion of 2- and 3-ring PAHs and a lower proportion of 5-ring PAHs. CB concentrations at all sites were low compared with UK estuarine sites and similar to sediment from more remote areas: however, BACs were exceeded. No significant trends were detected in either the sediment CB concentrations or patterns at any of the six sites. CB concentrations were significantly higher in fish liver collected from the Clyde. Concentrations at the other five sites were low, with the majority of samples having concentrations for the ICES7 CBs of <500 microg kg(-1) lipid weight. However, individual CB concentrations were still above the BACs. Hepatic EROD activities were measured in male plaice from 2002-2005 and were generally low (<10 pmol min(-1) mg protein(-1)). No temporal trends were detected in either CB concentrations or the EROD activity.     

Concentrations of polycyclic aromatic hydrocarbon in the surface sediments from inter-tidal areas of Kenting coast,Taiwan

The main objective of this study was to investigate the concentrations of polycyclic aromatic hydrocarbons (PAHs) in inter-tidal sediments of the Kenting coast, Taiwan, to assess the levels and origin of PAHs, and to provide useful information on the potential ecological risk of PAHs to benthic organisms. The total concentrations of 38 PAHs ranged from 0.2 to 493 ng/g dry weight. The high variation in total PAH concentrations was caused by the sand content of the sediment in the area. Compared with other coasts and bays in the world, the concentrations of PAHs in the inter-tidal surface sediment of the Kenting coast is low to moderate. Based on the sediment quality guidelines, the total PAH concentrations were below the effects range low value, indicating that the PAH levels in the Kenting area were within minimal effects ranges for benthic organisms. Principal component analysis and isomer ratios were analyzed to identify the contamination source in the inter-tidal surface sediment of the Kenting coast. The results of compounds’ pattern and origin analysis suggest that the source of PAHs in the inter-tidal surface sediment of the Kenting coast is the combustion of petroleum and biomass.     

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.     

The polycyclic aromatic hydrocarbon and geochemical biomarker composition of sediments from sea lochs on the west coast of Scotland

Sediments from twelve sea lochs on the west coast of Scotland were analysed for parent and branched 2- to 6-ring polycyclic aromatic hydrocarbons (PAHs), n-alkanes and geochemical biomarkers (triterpanes). Where possible at least fourteen sediment samples were collected at random from each sea loch. All sea lochs were remote, most had limited industrial and urban inputs, although all had fish farms. Four lochs had moderate total PAH concentrations and eight lochs had high total PAH concentrations. Total PAH concentration was related to organic carbon content and particle size distribution, with sandier sediments having lower PAH concentrations. The highest total PAH concentrations, normalised for organic carbon, were in Loch Linnhe and Ballachulish Bay (Loch Leven), close to an aluminium smelter. PAH concentration ratios showed that pyrolysis was the main source of PAHs in most lochs. Only sediments from Loch Clash showed evidence of petrogenic input based on their geochemical biomarker (triterpane and sterane) and n-alkane profiles. PAH profiles were similar across lochs apart from Loch Linnhe and Ballachulish Bay, which had a greater proportion of heavy parent PAHs. West coast sediments had a smaller proportion of heavy PAHs than sediments collected from voes in Shetland and a smaller proportion of alkylated PAHs relative to sediments collected from coastal waters around Orkney.     

Polycyclic aromatic hydrocarbons in river sediments from the western and southern catchments of the Bohai Sea, China: toxicity assessment and source identification

The concentration, distribution, and origin of 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) were investigated in river sediments from the western and southern catchments of the Bohai Sea, China. A toxicity assessment of 28 sediment samples collected from 15 main rivers was conducted by utilizing threshold and probable effect concentrations (TEC and PEC, respectively) derived from consensus-based sediment quality guidelines. The concentrations of total PAHs (∑PAH₁₆) ranged from 0.14 to 10,757 μg/kg dry weight (mean?=?1,368.6 μg/kg). The high concentrations of PAHs found in Binhai New Area of Tianjin and Binzhou City are likely the result of rapid population and heavy industry growth, resulting in elevated point and nonpoint source inputs of PAHs. Of the samples collected, samples 1 and 10 (7.1 % of the total) were categorized as toxic since some of the PAH concentrations exceeded the corresponding PECs. Twenty samples were classified as nontoxic, with both the individual PAH and the∑PAH₁₆ concentrations falling below the corresponding TECs. Analyses of selected PAH isomer ratios aided in the identification of PAH origins, allowing for a discrimination between pyrogenic and petrogenic sources. Spatial variability confirmed source heterogeneity within the study area. The most significant PAH-associated contamination was found in the Beitang River and Ji Canal, which are located in Binhai New Area. The magnitude of contamination and the likelihood of an ongoing influx of PAHs support the need for a better understanding of pollution sources and methods for both control and sediment restoration.     

Fugacity approach to evaluate the sediment-water diffusion of polycyclic aromatic hydrocarbons

Diffusion is an important process for sediment-water exchange and plays a vital role in controlling water quality. Fugacity fraction (ff) was used to estimate the sediment-water diffusion of polycyclic aromatic hydrocarbons (PAHs) between seawater and surficial sediment. A total of 33 surface sediment and sea water samples were collected concurrently from the northeast coastal area in China and 25 PAHs were analyzed including the alkylated and chlorated PAHs. Fugacity fraction was calculated based on the PAH concentrations in water and sediment, octanol-water partition coefficient of PAHs, organic matter content in sediment, and density of sediment. The calculated results showed that ff increased with decreasing molecular weight of PAHs. The low molecular weight PAHs (2-3 rings) transferred from sediment to water and the sediment acted as a secondary source to the water. The medium molecular weight PAHs (4-5 rings) were close to the sediment-water equilibrium and the transfer tendency shifted between sediment and water. The high molecular weight PAHs (5-6 rings) transferred from water into sediment and the sediment acted as a sink. Soot carbon and the difference of PAH concentrations between sediment and water were found to be important factors affecting the sediment-water diffusion. This study provided new insight into the process of sediment-water diffusion, which has a great influence on the quality of water, especially in severely-polluted sediment areas.     

Assessment of PAH pollution in the southern Baltic Sea through the analysis of sediment, mussels and fish bile

The concentrations of fifteen PAH compounds in samples of sediment and blue mussel tissue (Mytilus trossulus) were measured. In addition, the biliary polycyclic aromatic hydrocarbon metabolites present in flounder (Platichthys flesus) were analysed. Two methods were used in the analysis of PAH metabolites; high performance liquid chromatography (HPLC) and fixed wavelength fluorescence (FF). The major PAH metabolite which could be measured using the HPLC method was 1-OH pyrene. It was possible to detect 1-OH Phe and 3-OH B[a]P in 70 and 24 samples respectively, of the 87 samples analysed. However, the concentrations of 1-OH Phe and 3-OH B[a]P were below or near to the LOQ (0.002 μg ml(-1) bile). The bile of flounder samples from the Gulf of Gdańsk had 1-OH Pyr concentrations which ranged from 0.019 to 0.066 μg ml(-1) bile. The high linear correlation observed between the quantity of 1-OH pyrene determined by the HPLC-F method and the content of the sum of pyrene-type PAHs obtained by the FF method indicated the FF method of determination of pyrene-type PAH metabolites can be used as a screening method. The content of ∑(15)PAHs in sediments collected in the Gulf of Gdansk, in 2008, ranged from 29.3 to 103 μg kg(-1) dw. In mussel tissue ∑(15)PAHs concentrations were between 173.2 μg kg(-1) dw and 237.7 μg kg(-1) dw. All concentrations measured in the current study, in mussel tissue, were below the OSPAR toxicity threshold values.     

The Distribution and Sources of Polycyclic Aromatic Hydrocarbons in Surface Sediments Along the Egyptian Mediterranean Coast

Coastal marine sediment samples were collected from 31 sampling stations along the Egyptian Mediterranean Sea coast. All sediment samples were analyzed to determine aliphatic and polycyclic aromatic hydrocarbons (PAHs) as well as total organic carbon (TOC) contents and grain size analysis. Total concentrations of 16 EPA-PAHs in the sediments were varied from 88 to 6338 ng g⁻¹ with an average value of 154 ng g⁻¹ (dry weight). However, the concentrations of total aliphatic were varied from 1.3 to 69.9 ng g⁻¹ with an average value of 15.6 ng g⁻¹ (dry weight). The highest contents of PAHs were found in the Eastern harbor (6338 ng g⁻¹), Manzala (5206 ng g⁻¹) and El-Jamil East (4895 ng g⁻¹) locations. Good correlations observed between a certain numbers of PAH concentrations allowed to identify its origin. The average total organic carbon (TOC) percent was varied from 0.91 to 4.54%. Higher concentration of total pyrolytic hydrocarbons (∑COMB) than total fossil hydrocarbons (∑PHE) declared that atmospheric fall-out is the significant source of PAHs to marine sediments of the Egyptian Mediterranean coast. The selected marked compounds, a principal component analysis (PCA) and special PAHs compound ratios (phenanthrene/anthracene vs fluoranthene/pyrene; ∑COMB/∑EPA-PAHs) suggest the pyrogenic origins, especially traffic exhausts, are the dominant sources of PAHs in most locations. Interferences of rather petrogenic and pyrolytic PAH contaminations were noticed in the harbors due to petroleum products deliveries and fuel combustion emissions from the ships staying alongside the quays.     

Occurrence, source apportionment and toxicity assessment of polycyclic aromatic hydrocarbons in surface sediments of Chaohu, one of the most polluted lakes in China

In order to evaluate the effect of local anthropogenic activities on Chaohu Lake, one of the most eutrophicated lakes in China, surface sediments have been collected from the whole lake with 0.05 × 0.05 degree latitude/longitude resolution and in the estuaries of three main inflowing rivers. The concentrations of the 28 polycyclic aromatic hydrocarbons (PAHs) determined were in a range 82.4-13,000 ng g(-1) with an average value of 1670 ng g(-1) dry weight for total 28 PAHs (referred to as Σ(28)PAH). Amongst the 28 PAHs, 16 are listed as high priority PAHs by the USEPA and they were in the range of 60.8-10,200 ng g(-1) with an average value of 1230 ng g(-1) for the total of them (referred to as Σ(16)PAH); 7 are known as carcinogenic PAHs and their levels ranged from 34.2 to 6400 ng g(-1) with an average of 815 ng g(-1) in total (referred to as Σ(7)PAH). Chaohu Lake was considered significantly polluted by PAHs through the comparison with the PAH burdens in fresh-water lakes both in China and worldwide. Toxic units (TUs) evaluation showed some sampling locations possibly were over the median lethal level for benthic invertebrate. The highest PAH concentrations were found in sediments from the Nanfei River estuary, suggesting the major contributor of PAHs contamination to the lake. The PAHs with four and five rings were found to be dominant among the PAHs detected in all of the sediment samples, and perylene was the most abundant. Σ(16)PAH had a good correlation with those PAHs from pyrogenic sources, such as anthracene and phenanthrene, but a poor correlation with perylene. The results demonstrated that the environmental behavior of PAHs from pyrogenic sources is significantly different to that of perylene from diagenetic sources. The PAHs in sediments were mainly from traffic-related emission by qualitatively assessing with the diagnostic ratios of PAH isomers, and the ratios for low molecular weight PAHs were strongly altered during their transport.     

Monitoring effects of remediation on natural sediment recovery in Sydney Harbour, Nova Scotia

Chemical contaminants were assessed in Sydney Harbour, Nova Scotia during pre-remediation (baseline) and 3 years of remediation of a former coking and steel facility after nearly a century of operation and historical pollution into the Sydney Tar Ponds (STP). Concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, metals, and inorganic parameters measured in sediments and total suspended solids in seawater indicate that the overall spatial distribution pattern of historical contaminants remains unchanged, although at much lower concentrations than previously reported due to natural sediment recovery, despite remediation activities. Measured sediment deposition rates in bottom-moored traps during baseline were low (0.4–0.8 cm?year^?1), but during dredging operations required for construction of new port facilities in the inner Sydney Harbour, sedimentation rates were equivalent to 26–128 cm year^?1. Measurements of sediment chemical contaminants confirmed that natural recovery rates of Sydney Harbour sediments were in broad agreement with predicted concentrations, or in some cases, lower than originally predicted despite remediation activities at the STP site. Overall, most measured contaminants in sediments showed little temporal variability (4 years), except for the detection of significant increases in total PAH concentrations during the onset of remediation monitoring compared to baseline. This slight increase represents only a short-term interruption in the overall natural recovery of sediments in Sydney Harbour, which were enhanced due to the positive impacts of large-scale dredging of less contaminated outer harbor sediments which were discharged into a confined disposal area located in the inner harbor.     

Long-term fate of polycyclic aromatic hydrocarbons (PAH) in sediments from Loch Leven after closure of an aluminium smelter

An aluminium smelter discharged polycyclic aromatic hydrocarbons (PAHs) into Loch Leven on the west of Scotland from 1907 until it closed in 2000, resulting in elevated PAH concentrations in the sediment. A temporal monitoring programme to investigate any recovery in sediment concentrations began in 2004, with sampling each year until 2008 and again in 2010. Cores were also collected to investigate temporal trends over a longer time scale and to estimate the sedimentation rate in the loch. The loch is divided into two basins, and PAH concentrations were significantly higher in the upper basin, closer to the smelter, than in the lower basin. The PAH distribution and concentration ratios were consistent with a pyrolytic source of PAHs, with a high proportion of heavier parent PAHs. There was no evidence of any recovery in PAH concentrations, perhaps due to the mixing and disturbances of the sediment, and the persistence of PAHs. Concentrations of all PAHs were above the Background Assessment Concentrations (BACs) in both basins. In the lower basin only the 5- and 6-ring PAHs were above the Effects Range Low (ERL) values, but in the upper basin all but naphthalene were above the ERLs. There is therefore still an unacceptable risk of chronic effects in marine species. Concentrations decreased down the cores, falling below BACs in the deepest sections. However, ERLs were exceeded as far down the core as 30 cm for some PAHs.     

PAHs in the urban air of Sarajevo: levels,sources, day/night variation,and human inhalation risk

Polycyclic aromatic hydrocarbons (PAHs) are organic pollutants derived from pyrolysis and pyrosynthesis processes. Industrial activity, motor vehicle emission, and domestic combustion are the main sources of PAHs in the urban atmosphere. In this work, samples collected during the day and night in the urban area of Sarajevo are analyzed separately for gaseous and particle-bound PAHs; the possible origin of PAHs at the receptor site was suggested using different methods applied to the solid phase and to the total PAHs (gaseous + particulate phase). Finally, the risk level in Sarajevo associated to the carcinogenic character of the studied PAHs has been assessed. The result of this study suggests that (a) the total PAH concentrations were higher than those reported in other European cities; (b) the PAH daytime concentrations are higher than nocturnal concentrations: the sum of the PAH day/night ratios is 1.52 (gas) and 1.45 (particle phase); (c) stationary combustion and traffic were suggested to be the main sources of PAHs; (d) the average particle-bound benzo(a)pyrene (BaP) concentration (5.4 ng/m³) is higher than EU target annual value (1 ng/m³); and (e) PAH cancer risk exceeds the carcinogenic benchmark level recommended by the EPA mainly due to BaP during both the day and night periods.     

Polycyclic aromatic hydrocarbons in surface water and bed sediments of the Hungarian upper section of the Danube River

This study was performed to elucidate the distribution, concentration trend and possible source of polycyclic aromatic hydrocarbons (PAHs) in surface water and bed sediments of the Hungarian upper section of the Danube River and the Moson Danube branch. A total of 217 samples (water and sediments) were collected from four different sampling sites in the period of 2001–2010 and analysed for the 16 priority US Environmental Protection Agency PAHs. Concentrations of total 16 PAHs (∑PAHs) in water samples ranged from 25 to 1,208 ng/L, which were predominated by two- and three-ring PAHs. The ∑PAH concentrations in sediments ranged from 8.3 to 1,202.5 ng/g dry weight. Four-ring PAHs including fluoranthene and pyrene were the dominant species in sediment samples. A selected number of concentration ratios of specific PAH compounds were calculated to evaluate the possible sources of PAH contamination. The ratios reflected a pattern of pyrogenic input as a major source of PAHs. The levels of PAHs determined were compared with other sections of the Danube and other regions of the world.     

Aliphatic and polycyclic aromatic hydrocarbons in sediments of Kaohsiung Harbour and adjacent coast, Taiwan

Surficial sediment samples collected from Kaohsiung Harbour and its nearby coast were analyzed for aliphatic hydrocarbons and parent polycyclic aromatic hydrocarbons (PAHs). According to our results, the average total concentrations of n-alkanes (n-C₁₂ to C₃₅) and aromatics (15 PAHs) were 4.33 µg g^–1 dry weight (ranged 0.46–22.60) and 0.59 µg g^–1 dry weight (ranged 0.09–1.75), respectively. The highest concentrations of aliphatic and aromatic hydrocarbons were recorded in stations near the estuaries of Qianzhen River and Love River, respectively. Aliphatic hydrocarbons in the samples indicate that there has been significant non-petrogenic, possibly terrestrial, contribution in the sediment of the open coast of Kaohsiung Harbour and that there has been dominant contribution from petrogenic sources in the sediment of the inner harbour. PAHs, detected in the samples, however, indicated a higher pyrolytic contribution in open-coast samples and a higher petrogenic contribution in the inner harbour. Overall, sediment concentrations of total alkanes in this study were comparable to those found in Victoria Harbour, Hong Kong and are higher than those found in Xiamen Harbour, China. Concentrations of total PAHs in inner Kaohsiung Harbour sediments were relatively lower than those found in Victoria Harbour, Hong Kong and Xiamen Harbour, China, but comparable to those found in Hsin-ta Harbour, Taiwan and Incheon Harbour, Korea. In comparison with several effect-based sediment quality guidelines, most PAH concentrations found in samples taken from inner harbour stations exceeded the Threshold Effect Level of Florida indicating a slight possibility of adverse effects.     

Bioaccumulation of PAHs in the Zebra Mussel at Times Beach, Buffalo, New York

The zebra mussel, Dreissena polymorpha, was utilized in an in situ study in the Times Beach Confined Disposal Facility (CDF) located in Buffalo, New York, Mussels, placed both in the water column (upper position) and at the sediment surface (lower position), survived a 34-day exposure to the CDF. At the CDF, total polycyclic aromatic hydrocarbon (PAH) concentrations in the water column were below detection limits (<0.010 mg 1-1), mean total PAH concentrations in the sediment were 164.41 mg kg-1, and mean total PAH concentrations in mussel tissues after the 34-day exposure were 6.58 mg kg-1. PAH concentrations in mussels exposed for 34 days at the CDP were compared to a baseline PAH concentrations in mussel tissue prior to study initiation (Day 0), and mussel tissue from the reference site (Black Rock Channel Lock). There was a significant increase in total PAHs in mussel tissues over the 34 Day period at the CDF. No significant accumulation occurred at the reference site. PAHs which increased significantly in mussel tissue at the CDF were fluoranthene, pyrene, chrysene, and benzo(a)anthracene. Benzo(a)anthracene concentrations increased significantly in mussels at the upper position overall at Times Beach. Concentrations of Total PAHs, fluoranthene, pyrene, and chrysene were not related to position.     

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.     

Description and evaluation of a sampling system for monitoring hydrocarbons in sediments

A composite random sampling design was used to estimate the concentrations of hydrocarbons in sediments from two near-shore areas of Scotland (Firth of Clyde and Firth of Forth). The aim of this work was to estimate a mean value for each parameter in these areas, and to determine whether this can be done with more thorough coverage (better representation), better precision and less variance at lower analytical cost through a composite random sampling scheme rather than a simple random sampling scheme, and thereby contribute to the re-design of the UK National Marine Monitoring Programme (NMMP), re-named the UK Clean Seas Environmental Monitoring Programme (CSEMP) in 2006. Samples were collected using a simple random sampling design during 2005. All sediment samples were analysed for their particle size distribution and total organic carbon (TOC). All sediments were analysed for polycyclic aromatic hydrocarbons (PAHs) and n-alkanes. The concentrations of PAHs and n-alkanes in the study areas are described, and sources of PAHs were investigated through the PAH distributions and n-alkane profiles. Individual sediment samples from each area were combined to give a series of composite sub-samples, each comprised of 5 individual sediment samples. These composite samples were re-analysed for the same parameters as the individual samples. Mean total PAH (2- to 6-ring parent and branched) concentrations, based on the individual original sediment samples collected through simple random sampling, were 1858 microg kg(-1) dry weight (SE = 196 microg kg(-1) dry weight, n = 25) and 532.4 microg kg(-1) dry weight (SE = 59 microg kg(-1) dry weight, n = 25) in the Clyde and Forth, respectively. Mean total PAH concentrations of the composite samples were 1745 microg kg(-1) dry weight (SE = 121.0 microg kg(-1) dry weight, n = 5) in the Clyde and 511.6 microg kg(-1) dry weight (SE = 37.4 microg kg(-1) dry weight, n = 5) in the Forth. No significant differences were found between the mean PAH concentrations from the two sampling designs. This study demonstrated that the composite random sampling design gave a mean value with less variance than the simple random sampling design, at significantly reduced analytical effort (and cost).