Polyaromatic Hydrocarbons In Sediments Research Articles

Eucalyptus saponin- and sophorolipid-mediated desorption of polycyclic aromatic hydrocarbons from contaminated soil and sediment

The potential for biosurfactant-mediated desorption of polyaromatic hydrocarbons (PAHs) was evaluated using PAH-spiked soil and sediment. PAH desorption behaviors and toxicity of novel saponin biosurfactant extracted from Eucalyptus camaldulensis leaves and sophoro-lipid biosurfactant were investigated. Their PAH desorption efficiencies were compared with rhamnolipid biosurfactant and the industrial-chemical surfactant, Tween 20. Based on the emulsification indices, the salt tolerance of surfactants up to 30 g/L NaCl followed the order of saponin > Tween 20 > sophorolipid > rhamnolipid, while the thermal stability over the range of 15 to 50 °C was in the order of sophorolipid > rhamnolipid > saponin > Tween 20. The saponin biosurfactant emulsion demonstrated the highest stability under a wide range of acidic to basic pHs. PAH extraction percentages of saponin and sophorolipid under the optimized surfactant concentration, volume, and incubation time were 30–50% and 30–70%, respectively. PAH desorption capacities of saponin and sophorolipid were comparable to that of rhamnolipid and Tween 20 for all matrices. Sophorolipid more efficiently desorbed low molecular weight PAHs in soil and sediment compared to the other three surfactants. Microbial respiration was used to determine biosurfactant toxicity to the soil/sediment microbiome and indicated no inhibition of respiration during 60 days of incubation, suggesting that sophorolipid- and saponin-mediated remediation may be sustainable approaches to remove PAHs from contaminated soils and sediments.

Sources and Toxicity Effects of Polyaromatic Hydrocarbons (PAH) in Water Resources and Sediments

PAH’lar, iki veya daha fazla aromatik halkayı bünyesinde bulunduran, yarı uçucu organik bileşiklerdir. Su ortamlarında PAH konsantrasyonları ve etkileri son yıllarda üzerinde önemle durulan konuların başında gelmektedir. Sedimentler, su ortamındaki en önemli PAH rezervuarlarındandır. Bu nedenle sedimentler, sucul ekosistemlerinin su kalitesinin kirliliklerinin değerlendirmesinde sıklıkla kullanılmaktadır. PAH’lar organik bileşiklerin tam yanmamasından dolayı oluşmakta ve çeşitli kaynaklardan alıcı ortamlara ulaşabilmektedirler. PAH’lar çevre ve insan sağlığı açısından zararlı etkilere sahiptir ve endüstriyel gelişme ile doğal ortamlardaki PAH konsantrasyonlarında önemli artışlar olmuştur. Sanayi-yoğun havzalarda kentleşme ve endüstrileşmeden dolayı PAH miktarlarının yüksek olması beklenmektedir. Amerikan Çevre Koruma Ajansı (USEPA) tarafından belirlenen 16 öncelikli PAH türünün su kaynaklarında ve sedimentlerde izlenmesi, PAH’ların su ve sedimentlerdeki konsantrasyonlarının belirlenmesi ve PAH-toksisite ilişkisini ortaya konması açısından oldukça önemlidir. Bu çalışmada literatürdeki çalışmalar derlenerek dünyada bu konuda yapılmış çalışmaların sonuçları ortaya koymaktadır.

Butyltins, polyaromatic hydrocarbons, organochlorine pesticides, and polychlorinated biphenyls in sediments and bivalve mollusks in a mid-latitude environment from the Patagonian coastal zone.

Butyltins (BTs), polyaromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), and polychlorinated biphenyls (PCBs) were assessed in a mid-latitude environment of the Patagonian coast, distant from significant pollutant sources. Bioaccumulation processes through bottom sediment resuspension were suggested by BTs level (expressed as ng of tin [Sn] g(-1) dry wt) found in surface sediment (<limit of detection [LOD]-166.5 ng [Sn] g(-1) dry wt) and bivalve mollusks (29.4-206.0 ng [Sn] g(-1) dry wt); whereas imposex incidence was only 15% in the gastropod Pareuthria plumbea collected near a harbor. Low hydrocarbon pollution was found in sediments and bivalves with ∑PAHs(16) ranging from <LOD to 94.9 ng g(-1) dry weight and from <LOD to 54.9 ng g(-1) dry weight, respectively. Values were typical of locations distant from pollutant sources and showed different compositional patterns for both substrates. However, concentrations for some individual PAHs in sediments were found over the threshold effect level. On average, ΣPCB did not exceed the sediment quality guidelines being 0.57 ± 0.88 ng g(-1) dry weight in sediments and 0.41 ± 0.26 ng g(-1) dry weight in bivalves. Average ΣOCPs in sediments were 0.53 ± 0.34 ng g(-1) dry weight and ranged from <LOD to 0.22 ng g(-1) dry weight in bivalves, showing a different pattern and suggesting a different accumulation pathway as was found for PAHs. Although both discrete and atmospheric sources can be considered for PAHs, organochlorines pollution was clearly related to atmospheric global transport, indicating that in the studied area, OCPs and PCBs experience permanent or temporal deposition during their migration to southern zones.

Environmental Assessment of Polyaromatic Hydrocarbons in Sediment along Discharge Basin of Suez Oil Refinery Company, Southwest of the Suez Gulf

Environmental Assessment of Polyaromatic Hydrocarbons in Sediment along Discharge Basin of Suez Oil Refinery Company, Southwest of the Suez Gulf

Risk assessment of polycyclic aromatic hydrocarbons in the West Port semi-enclosed basin (Malaysia)

Sediment samples collected from the West Port, the west coastal waters of Malaysia, were analyzed by standard methods to determine the degree of hydrocarbon contamination and identify the sources of polyaromatic hydrocarbons (PAHs). Concentrations of PAHs in the port sediments ranged from 100.3 to 3,446.9 μg/kg dw. The highest concentrations were observed in stations close to the coastline, locations affected by intensive shipping activities and industrial input. These were dominated by high-molecular-weight PAHs (4–6 rings). Source identification showed that PAHs originated mostly pyrogenically, from the combustion of fossil fuels, grass, wood, and coal or from petroleum combustion. Regarding ecological risk estimation, only station 7 was moderately polluted, the rest of the stations suffered rare or slight adverse biological effects with PAH exposure in surface sediment, suggesting that PAHs are not considered as contaminants of concern in the West Port.

Comparison of fate profiles of PAHs in soil, sediments and mangrove leaves after oil spills by QSAR and QSPR

First order removal rates for 15 polyaromatic hydrocarbons (PAHs) in soil, sediments and mangrove leaves were compared in relation to the parameters used in fate transport analyses (i.e., octanol–water partition coefficient, organic carbon–water partition coefficient, solubility, diffusivity in water, HOMO–LUMO gap, molecular size, molecular aspect ratio). The quantitative structure activity relationships (QSAR) and quantitative structure property relationships (QSPR) showed that the rate of disappearance of PAHs is correlated with their diffusivities in water as well as molecular volumes in different media. Strong correlations for the rate of disappearance of PAHs in sediments could not be obtained in relation to most of the parameters evaluated. The analyses showed that the QSAR and QSPR correlations developed for removal rates of PAHs in soils would not be adequate for sediments and plant tissues.

Sources and distribution of aliphatic and polyaromatic hydrocarbons in sediments from the Neuquen River, Argentine Patagonia

Spatial distribution and probable sources of aliphatic and polyaromatic hydrocarbons (AHs, PAHs) were investigated in surface sediments collected along the bank of the Neuquen River, Argentina. Total concentrations of aliphatic hydrocarbons ranged between 0.41 and 125 μg/g dw. Six stations presented low values of resolved aliphatic hydrocarbons and the n–alkane distribution indexes applied suggested a clear biogenic source. These values can be considered the baseline levels of aliphatic hydrocarbons for the river sediments. This constitutes important information for the assessment of future impacts since a strong impulse in the exploitation of shale gas and shale oil in these zones is nowadays undergoing. For the other 11 stations, a mixture of aliphatic hydrocarbons of petrogenic and biogenic origin was observed. The spatial distribution reflects local inputs of these pollutants with a significant increase in concentrations in the lower course, where two major cities are located. The highest values of total aliphatic hydrocarbons were found in this sector which, in turn, was the only one where individual PAHs were detected.

Estimation of measurement uncertainty of pesticides, polychlorinated biphenyls and polyaromatic hydrocarbons in sediments by using gas chromatography–mass spectrometry

The evaluation of the uncertainty associated to analytical methods is essential in order to demonstrate quality of a result. However, there is often lack of information about uncertainty of methods to estimate persistent organic pollutants concentration in complex matrix. Current work has thoroughly evaluated uncertainty associated to quantification of several organochloride pesticides, PCBs and PAHs in sediments. A discussion of the main contributions to the overall uncertainty is reported, allowing authors to establish the accuracy of results and plan future improvements. Combined uncertainties ranged between 5–9% (pesticides), 4–7% (PCBs) and 5–10% (PAHs), being uncertainty derived of calibration the main contribution. Also, the analytical procedure was validated analysing a standard reference material (IAEA-408).

Sources and distribution of aliphatic and polyaromatic hydrocarbons in sediments of Sfax, Tunisia, Mediterranean Sea

This investigation is the first extensive study of the spatial distribution and sources of hydrocarbons in surface sediments from the Sfax–Kerkennah coastal zone (Tunisia). We show that the Sfax–Kerkennah coastal zone suffers from serious problems of pollution due to petroleum contamination. Analyses performed by GC/FID and GC/MS permitted a precise determination of both aliphatic and alicyclic compounds ( n-alkanes, isoprenoids, hopanes, steranes, diasteranes and unresolved complex mixture of fossil hydrocarbons and highly degraded organic matter (UCM)) and polycyclic aromatic hydrocarbons (PAHs). Non-aromatic hydrocarbon concentrations vary in the range = 16–1729 μg/g sediment d.w., and PAH concentrations vary in the range = 0.11–10.72 μg/g sediment d.w. These concentrations are relatively high, compared to other Mediterranean sites (37 examined sites). n-Alkane, UCM and PAH concentrations with biomarker profiles together prove the presence of a limited petrogenic contamination in sediments close to the Kerkennah Island, 22 km from the harbour of Sfax. In contrast, moderate to high petrogenic contamination is detected in the Sfax area sediments, notably closer to the storage tanks of hydrocarbons. Contaminant patterns indicate that PAHs originate mainly from fossil sources, with higher pyrolytic contributions near industrialized and urban areas. GC/MS analyses indicate the omnipresent contamination by petroleum. This contamination is confirmed by the identification of hopanes with predominant C 29 and C 30 α,β compounds and steranes with predominance of C 29, C 28 and C 27 compounds.

Sources and distribution of aliphatic and polyaromatic hydrocarbons in sediments of Jiaozhou Bay, Qingdao, China

The composition and distribution of aliphatic ( n-alkanes) and polyaromatic hydrocarbons (PAHs) were measured for the surface sediments collected at 25 sites from Jiaozhou Bay, Qingdao, China. Total n-alkanes and PAH concentrations ranged from 0.5 to 8.2 μg/gdw and 0.02 to 2.2 μg/gdw, respectively, and the distribution of both n-alkanes and PAHs showed large spatial variations in the bay. The distribution of PAHs in the sediments was predominated by the three or more ring compounds. High hydrocarbon levels were generally found in the areas associated with high anthropogenic impact and port activities in the bay. The calculated hydrocarbon indexes suggest that petroleum contamination was the main source of n-alkanes, while both pyrolytic and petrogenic sources contributed PAHs to the surface sediments of Jiaozhou Bay. In comparison to other polluted coastal sediments, the level of contamination from both aliphatic hydrocarbons and PAHs in Jiaozhou Bay sediments is relatively low at the present time.

PAHs contamination and PAH-degrading bacteria in Xiamen Western Sea

Six stations were established in Xiamen Western Sea (24°29’ N, 118°04’ E) on summer and autumn cruises in July and October 2001 to investigate the level of polyaromatic hydrocarbons (PAHs) and PAHs-degrading bacteria in surface water and sediments. PAHs in the surface water were mainly dominated by low molecular weight PAH compounds (2–3 rings PAH) in July and by high molecular weight PAH compounds (4–6 rings PAH) in October. PAHs in sediments were mainly dominated by high molecular weight PAH compounds (4–6). The percentage of 4–6 rings PAH to total PAHs ranged from 80.4 to 94.9% in July and 78.3 to 88.7% in October. No correlation was found between Fluoranthene-degrading bacteria numbers and Fluoranthene concentration among different stations in the surface water on the two cruises, and the same situation occurred between Pyrene-degrading bacteria numbers and pyrene concentration. But the numbers of fluorene- and phenanthrenedegrading bacteria were positively related to the fluorene and phenanthrene concentrations respectively. In the sediments, a significant positive relationship was found between PAH-degrading bacteria and PAHs concentration, except at station 6 on the two cruises.

Pressurized hot water extraction coupled on-line with LC-GC: determination of polyaromatic hydrocarbons in sediment.

Pressurized hot water extraction (PHWE) was directly combined with a LC-GC system for the determination of polyaromatic hydrocarbons (PAHs) in sediment. The sediment sample was first extracted with pressurized hot water, and the analytes were adsorbed into a solid-phase trap. The trap also functioned as a LC column, which removed most of the interfering matrix components. The 780-microL LC fraction containing the analytes was directly transferred to the GC using an on-column interface. The whole PHWE-LC-GC analysis took place in a closed system, and no sample pretreatment was required. The sensitivity of the method was excellent due to the efficient concentration in the LC-GC system. Sensitivity was approximately 800 times better than in traditional systems. In addition, only a small amount of sample (10 mg) was required for the analysis. The PHWE-LC-GC method proved to be linear in the concentration range of 0.01-2 microg/g, the limits of quantification were below 0.01 microg/g for all the analytes, and the relative standard deviations were between 3 and 28%. LC cleanup and the improved sensitivity made detection with FID sufficient for the determination of analytes. The results were comparable to those obtained in an interlaboratory comparison study as well as to the results obtained with off-line SFE-GC-MS.

Gas chromatographic and capillary gas chromatographic/mass spectrometric determination of organic sulfur compounds (OSCs) in sediment from ports: Significance of these compounds as an oil pollution index

Oil pollution arises in waters near petroleum industrial districts. In oily odor fish caught in the coast near petroleum industries, toluene, other aromatic hydrocarbons and olefinic hydrocarbons have been detected. The authors also reported the presence of organic sulfur compounds (OSCs), probably originating from polluting oil, in fish caught in the Seto Inland Sea after an accidental oil spilling from a tank. In a previous study, the authors detected OSCs in the oyster and mussel caught in the Seto Inland Sea. However, the presence of OSCs and polyaromatic hydrocarbons (PAHs) in sea sediments has not been described. In the present report, OSCs and PAHs in the sea sediments collected in several ports facing Seto Inland Sea were analyzed by a gas chromatographic/mass spectrometric (GC-MS) system.