Use of Compound-Specific Stable Isotope Analysis to Source Anthropogenic Natural Gas-Derived Polycyclic Aromatic Hydrocarbons in a Lagoon Sediment (original) (raw)
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Polycyclic aromatic hydrocarbons in ancient sediments and their relationships to palaeoclimate
Organic Geochemistry, 1998
ÐCombustion-derived and land-plant-derived polycyclic aromatic hydrocarbons (PAHs) have been investigated for an Upper Triassic to Middle Jurassic sedimentary sequence from the Northern Carnarvon Basin, Western Australia. The former included¯uoranthene, pyrene, benzo¯uoranthenes, benzo[e]pyrene and benzo[a]pyrene, and the latter included retene, cadalene and simonellite. Combustion-derived PAHs are most abundant in the Upper Triassic and late Lower Jurassic sediments. The abundances of land-plant-derived markers all maximise in the upper part of the Lower Jurassic section, but vary independently of one another through time. The changes in the relative abundances of these markers have been related to the variation of regional climatic conditions, especially the changes in humidity and seasonality during the Late Triassic to Middle Jurassic times.
Marine Chemistry, 1993
. Dissolved, particulate and sedimentary naturally derived polycyclic aromatic hydrocarbons in a coastal environment: geochemical significance. Mar. Chem.,. Polycyclic aromatic hydrocarbons (PAH) derived from natural precursors have been analysed in superficial sediments and waters in the deltaic area of the Rhrne river. This area is characterized by major water and solid inputs from the Rhrne river into the Mediterranean Sea. Nine superficial sediment samples were collected in , with further separation of particulate and dissolved phases. After extraction of lipids, isolation and fractionation of hydrocarbons by HPLC, PAH were analysed by GC and GC-MS. Retene and tetrahydrochrysenes (THCs) were the major naturally derived PAH detected in the Rhrne delta. They derive from diterpenoid and triterpenoid precursors, which are common constituents of terrestrial plants. In sediments, intermediate products were absent or at trace levels, suggesting that formation of natural PAH occurred mainly before deposition. Concentrations of retene and THCs were in the range 12.92-52.86 ngg-~ and 16.56-162.68 ngg -~ , respectively. Their distributions were different from those of anthropogenic PAH. Despite their common origin, retene and THCs did not show identical distributions and relations to parameters such as total organic carbon and terrestrial n-alkanes; these findings indicate that they follow different transport pathways, as a result of different particle associations. Estimations of retene and THC fluxes and the use of these markers for determining the percentage of 'terrestrial organic carbon' are presented. Analysis of water samples confirmed that naturally derived PAH were mainly formed before deposition, in soils of the drainage basin or during the early stages of riverine transport. The distributions of natural and anthropogenic PAH were different, which suggests that the carrier particles of natural PAH were coarser and settled more rapidly than those carrying anthropogenic PAH. However, retene and THCs did not appear to be associated with the same particle types, shown by distributional differences and by the presence of retene in the dissolved phase in contrast to THCs. Consequently, the distributional trends observed in sediments can be explained by the different aquatic transport of the various PAH classes as demonstrated by the analysis of water samples. Instantaneous fluxes were estimated in three seasons for both dissolved and particulate phases. They again showed decoupling between natural and anthropogenic PAH. Fluxes of natural PAH were strongly dependent on the river flow, whereas those of anthropogenic pAH were more dependent on emission rates. The dissolved phase was a significant factor in the transport of retene and of anthropogenic PAH. Naturally derived PAH, and more specifically THCs, appear to be promising tracers of inputs and dispersal of continental organic matter.
Sources of polycyclic aromatic hydrocarbons to the Guaratuba Bay, Brazil
The coasts of Bohai Sea (BS) and Yellow Sea (YS) in China support almost one-quarter of its population and provide more than one-third of the national GDP. BS and YS are downwind of the Asian continental outflow in spring and winter as influenced by the East Asian monsoon. This makes the two seas important sinks of land-based pollutants associated with the Asian continental outflow. The sixteen U.S. EPA proposed priority polycyclic aromatic hydrocarbons (PAHs) in 130 surface sediment samples collected from BS and YS were measured. Combined with our previous PAH data of 90 PM 2.5 samples from the upwind areas, the sources of the PAHs in BS and YS were apportioned using positive matrix factorization (PMF) modeling. Four sources were identified: petroleum residue, vehicular emissions, coal combustion and biomass burning. Petroleum residue was the dominant contributor of PAHs in the coast of the Bohai Bay probably due to Haihe River runoff, oil leakage from ships and offshore oil fields. The contribution of vehicular emissions in BS was higher than that in YS, and the reverse was true for coal combustion and biomass burning. This difference in the source patterns in the sediments of the two seas could be attributed to the different PAH emission features of the upwind area related to demographic and economic conditions, as well as the marine geography. The ratios of selected 4-6 ring PAHs in the sediments compared well with those of the PM 2.5 of the upwind areas, implicating that the particle phase PAHs in the atmosphere play an important role in the source to sink process of the pyrogenic PAHs in the region.
Organic Geochemistry, 2017
After the impoundment of the Three Gorges Reservoir (TGR), the hydrological situation of the 21 reservoir has changed greatly. The concentration and distribution of typical persistent organic 22 pollutants in water and sediment have also changed accordingly. In this study, the 23 concentration, distribution and potential sources of 16 polycyclic aromatic hydrocarbons 24 (PAHs) and 6 phthalic acid esters (PAEs) during the water drawdown and impoundment 25 periods were investigated in water and sediment from the TGR. According to our results, PAHs 26 and PAEs showed temporal and spatial variations. The mean ΣPAH and ΣPAE concentrations 27 in water and sediment were both higher during the water impoundment period than during 28 the water drawdown period. The water samples from the main stream showed larger ΣPAH 29 concentration fluctuations than those from tributaries. Both the PAH and PAE concentrations 30 meet the Chinese national water environmental quality standard (GB 3838-2002). PAH 31 monomers with 2-3 rings and 4 rings were dominant in water, and 4-ring and 5-6-ring PAHs 32 were dominant in sediment. Din -butyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP) 33 were the dominant PAE pollutants in the TGR. DBP and DEHP had the highest concentrations 34 in water and sediment, respectively. The main source of PAHs in water from the TGR was 35 petroleum and emissions from coal and biomass combustion, whereas the main sources of 36 PAHs in sediments included coal and biomass combustion, petroleum, and petroleum 37 combustion. The main source of PAEs in water was domestic waste, and the plastics and heavy 38 chemical industries were the main sources of PAEs in sediment Q5 .
Marine Chemistry, 1999
Dated sediment cores collected from Richardson and San Pablo Bays in San Francisco Bay were used to reconstruct a Ž . history of polycyclic aromatic hydrocarbon PAH contamination. The sedimentary record of PAHs in Richardson Bay shows that anthropogenic inputs have increased since the turn of the century, presumably as a result of increasing urbanization and industrialization around the Bay Area. Concentrations range from about 0.04-6.3 mg g y1 . The dominant origin of the PAHs contributing to this modern contamination is from combustion processes. Depth profiles in San Pablo Bay indicate higher concentrations of PAHs since the 1950s than during the late 1800s, also presumably resulting from an increase in urbanization and industrialization. Total PAHs in San Pablo Bay range from about 0.04-1.3 mg g y1 . The ratios Ž . of methylphenanthrenesrphenanthrene and methylfluoranthenesq methylpyrenes rfluoranthene were sensitive indicators of anthropogenic influences in the estuary. Variations in the ratio of 1,7-dimethylphenanthrener2,6-dimethylphenanthrene indicate a gradual replacement of wood by fossil-fuel as the main combustion source of PAHs in San Francisco Bay sediments. The profile of perylene may be an indicator of eroding peat from marshlands. q 1999 Elsevier Science B.V. All rights reserved.