Petroleum Hydrocarbons In Seawater Research Articles

Bioremediation of Petroleum Hydrocarbons in Seawater: Prospects of Using Lyophilized Native Hydrocarbon-Degrading Bacteria.

This work aimed to develop a bioremediation product of lyophilized native bacteria to respond to marine oil spills. Three oil-degrading bacterial strains (two strains of Rhodococcus erythropolis and one Pseudomonas sp.), isolated from the NW Portuguese coast, were selected for lyophilization after biomass growth optimization (tested with alternative carbon sources). Results indicated that the bacterial strains remained viable after the lyophilization process, without losing their biodegradation potential. The biomass/petroleum ratio was optimized, and the bioremediation efficiency of the lyophilized bacterial consortium was tested in microcosms with natural seawater and petroleum. An acceleration of the natural oil degradation process was observed, with an increased abundance of oil-degraders after 24 h, an emulsion of the oil/water layer after 7 days, and an increased removal of total petroleum hydrocarbons (47%) after 15 days. This study provides an insight into the formulation and optimization of lyophilized bacterial agents for application in autochthonous oil bioremediation.

Degradation of petroleum hydrocarbons in seawater by simulated surface-level atmospheric ozone: Reaction kinetics and effect of oil dispersant

Oil degradation by surface-level atmospheric ozone has been largely ignored in the field. To address this knowledge gap, this study investigated the ozonation rate and extent of typical petroleum compounds by simulated surface-level ozone, including total petroleum hydrocarbons (TPHs), n-alkanes, and polycyclic aromatic hydrocarbons (PAHs). Moreover, the work explored the effect of a prototype oil dispersant, Corexit EC9500A, on the ozonation rate. Rapid oxidation of TPHs, n-alkanes and PAHs was observed at various gaseous ozone concentrations (i.e. 86, 200 and 300 ppbv). Generally, the presence of the oil dispersant enhanced ozonation of the oil compounds. The addition of humic acid inhibited the reaction, while increasing salinity accelerated the degradation. Both direct ozonation by molecular ozone and indirect oxidation by ozone-induced radicals play important roles in the degradation process. The findings indicate that ozonation should be taken into account in assessing environmental fate and weathering of spilled oil.

Distribution of petroleum hydrocarbons in sea water of the Aden city -Yemen

This study is to determine the concentration and distribution of petroleum hydrocarbons residual in sea water in the coast of the city of Aden, Yemen, during three seasons: the first was in the period from 11 to 14 July 2014, the second was in December 2014, and the last was during March 2015,where the use of a gas chromatography and spectroflourometer to determine the characteristics of the hydrocarbons extracted. The results confirmed the concentration of hydrocarbons levels with regard the coast of to the city of Aden. The results showed that the concentrations of petroleum hydrocarbons in water ranging from 0.688715in Gold Mohour to 15.891754 µ /L in the refineries area, with an average concentration of 6.3269 µg /L. The study revealed that the level of hydrocarbons in sea water of the coast of thecity of Aden is close to the levels of petroleum hydrocarbons in the region and other parts of the world , after comparing their results with other regions of the world, which showed that it is low/ within the range in the permissible limits.

ECOLOGICALLY ACCEPTABLE WAY OF DEVELOPMENT OF THE NORTH CAUCASIAN FEDERAL DISTRICT AND PLANS FOR RESTORING TEREK RIVER BASIN

Aim. This paper analyzes the data on contamination of the Terek river basin in the period of 1978-2012. We give assessment to process of self-purification from oil pollution of coastal waters of the Dagestan coast of the Caspian Sea; tracked seasonal and long-term dynamics of the concentration of petroleum hydrocarbons in sea water, calculated an average concentration and load of petroleum hydrocarbons in the seaside area of Terek River. We also present information obtained in the course of fieldwork in Agrakhan Bay. As a result of field research we conducted full hydrochemical analysis of water samples taken at stations, evaluating the degree of water pollution of Agrakhan Bay. Materials and Methodology. We identified features of pollution of the seaside wellhead of Terek River by analyzing the information from the review journals of the state of environment and its pollution, and magazine-yearbooks of marine waters quality by hydrochemical indicators as well as our own data collections and analysis. Agrakhan Bay Research was conducted using modern physical and chemical methods of quantitative chemical analysis. The date was collected on an integrated basis at 16 stations. Results. It was found that anthropogenic load has reached its limits in the Terek basin. The main factor for the destruction of the ecology of Terek River constitutes extremely large number of oil extracting and refining industries in the region. Studies of Agrakhan Bay revealed a high concentration of zinc. We also found a slight excess of maximum permissible concentration of lead and copper in the southern part of the bay. Main conclusion. For the revival of the Terek River it is necessary to optimize the ecological and environmental impacts of activities of enterprises and industries, improve the efficiency of the entire economy of the North Caucasian region. It is crucial to combine environmental, economic, scientific, technical and organizational measures into a single set aimed at solving clearly defined problems of ecological rehabilitation, restoration of natural resources, socio-economic development of the region. It is important to develop and implement projects for the conservation of biological diversity of the Terek River.

CONCENTRATION OF PETROLEUM HYDROCARBONS IN SEA-WATER AND COASTAL SEDIMENT AROUND ADEN CITY-YEMEN

The present investigation was designed to determin of residual of petroleum hydrocarbons in seawater and sediments from Aden coasts, Yemeni, during April 2004. Additional hydrographic data such as air and water temperatures, salinity, dissolved oxygen, pH and total alkalinity were also determinated in order to give a better appraisal of survey data. The mean concentrations of residual petroleum hydrocarbons in seawater were varied from 19ng/ l at Al-OmalIsland to 239ng/l at free area and in sediment from 9ng/g at Al-OmalIsland to 45 infront of refinery. The study revealed comparable level of petroleum hydrocarbons in this region to that reported for other parts of the world, which showed no pollution with petroleum hydrocarbons

Degradation of petroleum hydrocarbons in seawater by ionizing radiation

A major concern with leaking petroleum is the environmental contamination by the toxic and water-soluble components such as benzene, toluene and xylenes (BTX). These hydrocarbons have relatively high pollution potential because of their significant toxicity. All BTX compounds are depressants to the central nervous system. Consequently, BTX are priority pollutants and their occurrence has led to the development of several physical, chemical and biological methods for their removal. The use of nuclear technology for protection and conservation of the environment, by the destruction of toxic organic compounds present in the environmental, drinking water, soils and industrial sewage has been the object of study of several authors in Brazil and in the world. The objective of this paper is to present the preliminary results of the study of contamination of the seawater by the main pollutants of the output and transport of petroleum, such as benzene, toluene and xylene, and their removal by the exposure to the ionizing radiation.

Biodegradation of Petroleum Hydrocarbons in Seawater at Low Temperatures (0–5 °C) and Bacterial Communities Associated with Degradation

In this study biodegradation of hydrocarbons in thin oil films was investigated in seawater at low temperatures, 0 and 5 degrees C. Heterotrophic (HM) or oil-degrading (ODM) microorganisms enriched at the two temperatures showed 16S rRNA sequence similarities to several bacteria of Arctic or Antarctic origin. Biodegradation experiments were conducted with a crude mineral oil immobilized as thin films on hydrophobic Fluortex adsorbents in nutrient-enriched or sterile seawater. Chemical and respirometric analysis of hydrocarbon depletion showed that naphthalene and other small aromatic hydrocarbons (HCs) were primarily biodegraded after dissolution to the water phase, while biodegradation of larger polyaromatic hydrocarbons (PAH) and C(10)-C(36) n-alkanes, including n-hexadecane, was associated primarily with the oil films. Biodegradation of PAH and n-alkanes was significant at both 0 and 5 degrees C, but was decreased for several compounds at the lower temperature. n-Hexadecane biodegradation at the two temperatures was comparable at the end of the experiments, but was delayed at 0 degree C. Investigations of bacterial communities in seawater and on adsorbents by PCR amplification of 16S rRNA gene fragments and DGGE analysis indicated that predominant bacteria in the seawater gradually adhered to the oil-coated adsorbents during biodegradation at both temperatures. Sequence analysis of most DGGE bands aligned to members of the phyla Proteobacteria (Gammaproteobacteria) or Bacteroidetes. Most sequences from experiments at 0 degree C revealed affiliations to members of Arctic or Antarctic consortia, while no such homology was detected for sequences from degradation experiment run at 5 degrees C. In conclusion, marine microbial communities from cold seawater have potentials for oil film HC degradation at temperatures < or =5 degrees C, and psychrotrophic or psychrophilic bacteria may play an important role during oil HC biodegradation in seawater close to freezing point.

The dissolution and photodegradation of Kuwaiti crude oil in seawater. Part 2: A laboratory photodegradation apparatus and photodegradation kinetics of a model seawater soluble hydrocarbon (phenanthrene)

A laboratory photodegradation apparatus, incorporating a calibrated xenon lamp, controlled temperature unit and quartz reaction cells designed to simulate natural irradiation by sunlight, and which is suitable for kinetic studies of hydrocarbon degradation in seawater, is described. The apparatus and experimental method was used to determine the pseudo-first order photodegradation constant (k p) of phenanthrene (a component present in the seawater-soluble fraction of crude oil) in seawater at 25 °C. The k p values determined in duplicate experiments were −0.342 ± 0.003 and −0.317 ± 0.029 h −1 with half-lives ( t 1 2 ) of 2.03 and 2.19 h. Extrapolation to natural sunlight at latitude 30 °N (Florida midday, midsummer assuming 12 h daylight) gave t 1 2 values of 8.6–9.5 h, suggesting that photodegradation is a significantly fast reaction for removal of phenanthrene from seawater under some conditions. Gas chromatography-mass spectrometry (GC-MS) and ultraviolet fluorescence spectrophotometry were both suitable methods for monitoring the degradation, but GC-MS was most suitable for the determination of photoproducts. The identifiable products amounted to some 12% of the total products after 7 h irradiation, and their distribution was consistent with a known mechanism of phenanthrene degradation involving formation of an unstable and reactive 9,10-epoxide. The photolysis method should prove valuable for the determination of k p and t 1 2 values for a wide range of petroleum hydrocarbons in seawater.

Estimates using fluorescence spectroscopy of the present state of petroleum hydrocarbon contamination in the water column of the northwest Atlantic Ocean

Concentrations of petroleum hydrocarbons in seawater from the general region between Nova Scotia and Bermuda were estimated using fluorescence spectroscopy. Concentrations in surface water (0–3 mm) averaged 20.4 μg/l, and in water from 1 and 5 m they averaged 0.8 and 0.4 μg/l respectively. No significant concentrations could be detected in deeper water. There was considerable variability in the concentrations suggesting that the distribution of oil in seawater is quite patchy, especially in surface waters. Seawater samples for hydrocarbon analysis cannot be collected with conventional sampling equipment. Due to adsorption problems, the inner surface of samplers must come into contact only with the water being sampled and must be rinsed with organic solvent after samples are removed. Because these precautions were not taken in previous investigations, much of the published data of hydrocarbons in seawater is unreliable.