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Hydrocarbon Contamination (hydrocarbon + contamination)
Selected AbstractsIsolation and characterization of naphthalene-degrading bacteria from sediments of Cadiz area (SW Spain)ENVIRONMENTAL TOXICOLOGY, Issue 5 2008D. Nair Abstract Petroleum hydrocarbon contamination of harbor sediments from shipping activity, fuel oil spills, and runoffs are becoming a great concern because of the toxicity and recalcitrance of many of the fuel components. Polycyclic aromatic hydrocarbons (PAHs) are of most concern due to their toxicity, low volatility, resistance to degradation, and high affinity for sediments. Microorganisms, especially bacteria, play an important role in the biodegradation of these hydrocarbons. The objective of the present study was to characterize and isolate PAH-(naphthalene) degrading bacteria in the coastal sediments of Cadiz (SW Spain), since this area is mostly polluted by PAH occurrence. A total of 16 naphthalene-utilizing bacteria were isolated from these sites. Introduction of bacteria isolated from contaminated sediments into mineral medium contributed to the increased rate of hydrocarbon utilization. The bacterial isolates obtained from these sites are very potent in utilizing naphthalene and crude oil. It would be interesting to assess if the selected naphthalene-degrading isolates may degrade other compounds of similar structure. Hence these isolates could be very helpful in bioremediating the PAH-contaminated sites. Further pursue on this work might represent eco-friendly solution for oil contamination on sea surface and coastal area. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008. [source] Epifluorescence microscopy and image analysis of high-level polycyclic aromatic hydrocarbon contamination in soilsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2006J. Chadwick Roper Abstract Interactions between polycyclic aromatic hydrocarbons (PAHs) and soil are an important determinant of their chemical availability and transport. Laboratory examination of microscale PAH,soil interaction is limited by the availability of methods for particle-scale observation. Inverted epifluorescence microscopy, combined with digital photography and computer image analysis, was evaluated for specificity and linearity using dissolved PAHs. A pyrene filter (excitation wavelength, 360,400 nm; emission wavelength, 450,520 nm) gave nonspecific PAH fluorescence, and bias for fluoranthene, benzo[b]fluoranthene, benzo[g, h, i]perylene, and benz[a]anthracene was quantified in comparison to that for pyrene. Concentrations ranging from 1 to 10 mM for anthracene, fluoranthene, and pyrene and from 1 to 50 mM for naphthalene produced a linear response with low interpixel variability. Liquid-phase analyses validated use of the technique for the descriptive analysis of PAH distribution in solid samples, but liquid-phase calibration was not quantitative for spiked or field-contaminated soils. The mean luminance for three field soils was proportional to the values predicted from their chemically measured concentrations and to values from spiked, aged, uncontaminated materials. Image analysis of laboratory- and field-contaminated samples determined the area distribution of fluorescent intensity and the size of fluorescent areas exceeding a threshold luminance. These qualitative descriptions of the microscale spatial distribution of PAH contamination are presented as potential endpoints for future research on biogeochemical interactions in heavily contaminated solids. [source] The response of protist and metazoan communities in permeable pavement structures to high oil loadingsTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 2 2005S. J. COUPE Permeable pavement structures (PPS) have been demonstrated to provide an efficient and sustainable method of controlling urban derived hydrocarbon contamination. Until recently, laboratory PPS mesocosm models have used crushed granite as the load bearing sub-base material. However, the use of virgin stone may not be the optimal choice of substrate, as this is not necessarily sustainable or cost effective in the long term when compared to the use of recycled materials. However, recycled materials such as waste concrete may change the environmental conditions in PPS mesocosms, and the characteristics of the eukaryotic community may become different from those which have been previously described. In the current experiment, granite and recycled concrete sub-base materials were compared for their ability to retain 900 g/m2 of clean mineral oil applied to the mesocosm surface. It was observed that, even at this very high oil loading, 99.95% of the applied oil was retained within granite and concrete-based structures, but the effluent was two pH units more alkaline in concrete mesocosms than granite. The eukaryotic microfauna in the effluent from both mesocosm types showed a ten-fold increase in protist abundance, and a doubling in the number of protist genera, compared with earlier work using only 18 g/m2 of applied oil. Five genera of testate amoebae not previously recorded in PPS were identified, these included Arcella, Assulina, Cryptodifflugia, Cyclopyxis and Difflugia in addition to the three genera observed previously using the lower oil application. Metazoan abundances increased from 1.5 × 101 organisms per ml using the lower oil loadings to 2.0 × 103/ml in the current experiment. Rotifers and nematodes were the most numerous, but tardigrades were also observed in both concrete and granite-based mesocosms. Despite the differences in effluent pH, it was apparent that there were only marginal differences in the eukaryotic microbiology of the two mesocosm types. This was thought to be due to the layered structural arrangement of the pavement and the location of the highly oil-retentive polypropylene geotextile and extensive biofilm layer positioned above the concrete sub-base. Work is now underway to find oil loadings that will adversely affect the abundance and diversity of eukaryotic organisms in PPS mesocosms. [source] Petroleum hydrocarbon contamination in boreal forest soils: a mycorrhizal ecosystems perspectiveBIOLOGICAL REVIEWS, Issue 2 2007Susan J. Robertson Abstract The importance of developing multi-disciplinary approaches to solving problems relating to anthropogenic pollution is now clearly appreciated by the scientific community, and this is especially evident in boreal ecosystems exposed to escalating threats of petroleum hydrocarbon (PHC) contamination through expanded natural resource extraction activities. This review aims to synthesize information regarding the fate and behaviour of PHCs in boreal forest soils in both ecological and sustainable management contexts. From this, we hope to evaluate potential management strategies, identify gaps in knowledge and guide future research. Our central premise is that mycorrhizal systems, the ubiquitous root symbiotic fungi and associated food-web communities, occupy the structural and functional interface between decomposition and primary production in northern forest ecosystems (i.e. underpin survival and productivity of the ecosystem as a whole), and, as such, are an appropriate focal point for such a synthesis. We provide pertinent basic information about mycorrhizas, followed by insights into the ecology of ecto- and ericoid mycorrhizal systems. Next, we review the fate and behaviour of PHCs in forest soils, with an emphasis on interactions with mycorrhizal fungi and associated bacteria. Finally, we summarize implications for ecosystem management. Although we have gained tremendous insights into understanding linkages between ecosystem functions and the various aspects of mycorrhizal diversity, very little is known regarding rhizosphere communities in PHC-contaminated soils. This makes it difficult to translate ecological knowledge into environmental management strategies. Further research is required to determine which fungal symbionts are likely to survive and compete in various ecosystems, whether certain fungal - plant associations gain in ecological importance following contamination events, and how PHC contamination may interfere with processes of nutrient acquisition and exchange and metabolic processes. Research is also needed to assess whether the metabolic capacity for intrinsic decomposition exists in these ecosystems, taking into account ecological variables such as presence of other organisms (and their involvement in syntrophic biodegradation), bioavailability and toxicity of mixtures of PHCs, and physical changes to the soil environment. [source] The Isiokpo Oil-Pipeline Leakage: Total Organic Carbon/Organic Matter Contents of Affected SoilsCHEMISTRY & BIODIVERSITY, Issue 8 2005The environmental impact of the 1997 leakage of the high-pressure crude-oil pipeline at Isiokpo in the Niger Delta in the southeast of Nigeria was evaluated, with particular reference to total-organic-carbon (TOC) and total-organic-matter (TOM) contents of soils within the vicinity of the oil spillage. The soils, taken from depths of 0,15,cm (surface) and 15,30,cm (subsurface), were found to be more acidic (pH,4.2,5.6) than the unpolluted soils, with a high average moisture content of 6.8%. The extractable hydrocarbon content ranged from 2.71,3.48,mg/kg, indicating hydrocarbon contamination. However, contrary to expectation, the TOC and TOM contents of the polluted soils did not show any significant increase in concentration, supposedly due to natural rehabilitation of the affected mat layer of soils. Thus, notwithstanding the possible proliferation of heterotrophic organisms by the presence of the added petroleum hydrocarbons, environmental conditions such as weathering and climatic predispositions, as well as physico-chemical parameters such as pH, moisture content, and temperature must have encumbered the carbon-mineralizing capacity of the heterotrophs, thereby reducing the turnover of carbon and the decomposition of organic matter. The restrictions by high moisture content might not come directly from H2O itself, but are probably a consequence of hindered soil ventilation, which reduces O2 supply and gaseous diffusion, conditions that might have been substantially aggravated by the added petroleum hydrocarbons. [source] | ||||||||||