Oil spill sample

Figure 3. Gas chromatograms of the aliphatic (fl) and aromatic (f2) fractions of the oil spill sample. The fl fraction contains identified n-alkanes in the range of n-C12 through n-C32 and pristane (pr) and phytane (py). UCM-unresolved complex mixture.

The chromatogram of the sediment sample extract (Figure 4) has a hydrocarbon distribution that could be the result of weathered petroleum products mixed with carbonized coal products. There is a UCM present in both the fl and f2 fractions, similar to the oil spill sample (Figure 3). The resolved fl fraction contained lower molecular wei t (n-C16 and below) n-alkanes, but n-C15 was not detected, as with the creosote sample (Figure 2). The higher molecular wei t resolved n-alkane peaks, n-C25,27,29 and 31 are Indicative of a biogenic input (12.) The resolved peaks in the f2 fraction are also similar to resolved f2 peaks found in the creosote sample (Figure 2). 

Figure 12 Comparison of oil spill samples in a difference image (between samples in May and November 2003) and a color addition image with the May sample in green and the November sample in red [57].

The upper concentration limit as defined by the deviation of the detector response from linearity caused by auto-quenching is approximately 8 mg oil/mL hexane. Thus, at very high concentrations of oil residues in the water that might be encountered under special circumstances in the immediate vicinity of an oil spill, samples may have to be dissolved in larger volumes of n-hexane for measurement or the extract diluted. 

Figure 1 Plot of weathering ratio (C3-dibenzo thiophenes C3-ehrysenes) versus souree ratio (C3-dibenzothio-phenes C3-phenanthrenes) for fresh and degraded oil samples from three different erude oil spills (Reprinted with permission from Environ. Sci. Technol, 30, 2332. 1996 Ameriean Chemieal Soeiety)...

Although comprehensive two-dimensional gas chromatography has not been applied to any great extent in forensic analysis, the technique shows great promise when samples or sample matrices are complex. For example, when oil is spilled into waterways, assigning responsibility for the economic and environmental damage is often difficult. Gaines et al. employed comprehensive two-dimensional GC in the forensic analysis of samples collected at oil-spill sites and were able to obtain results which were comparable to those obtained by classical methods (39). This article also... 

Comprehensive chemical analyses of samples of water, sediment, and biota were carried out both before and after the spill. This cannot of course be carried out in most cases, and illustrates a serious limitation in field studies, in which lack of background data or difficulty in finding an uncontaminated control locality is frequently encountered. Sum parameters were sparingly employed in Baffin Island Oil Spill (BIOS), and emphasis was placed on the analysis of specific compounds attention was directed not only to PAHs, but also to azaarenes, dibenzothiophenes, and hopanes. Thereby, a clear distinction could be made between the input from the oil deliberately discharged, and that arising from natural biological reactions or mediated by atmospheric transport. 

Rasmussen [82] describes a gas chromatographic analysis and a method for data interpretation that he has successfully used to identify crude oil and bunker fuel spills. Samples were analysed using a Dexsil-300 support coated open tube (SCOT) column and a flame ionisation detector. The high-resolution chromatogram was mathematically treated to give GC patterns that were a characteristic of the oil and were relatively unaffected by moderate weathering. He compiled the GC patterns of 20 crude oils. Rasmussen [82] uses metal and sulfur determinations and infrared spectroscopy to complement the capillary gas chromatographic technique. 

In view of these complexities, environmental studies that seek to verify proposed cause-effect relationships between contamination and response need to be carefully designed to avoid bias and misunderstanding. Most environmental assessments adopt a multi-tiered approach to testing, in which combinations of biological responses (biomarkers) are measured in tissue samples, body fluids or at the whole organism level to indicate exposure to or adverse effects of contamination.8. Auffret and colleagues60 surveyed Pacific oysters from the Atlantic coast of Brittany after the Erika oil spill between... 

Hennig [40] has applied ultraviolet spectroscopy to the determination of aromatic constituents of residual fuel oil in hexane extracts of marine sediment samples. Examination of the ultraviolet spectra of samples of an oil pollutant from a beach and crude oil, at various concentrations, revealed strong absorption maxima at approximately 228nm and 256nm. The ratio of the peak heights at these wavelengths is constant for a particular oil, and is independent of concentration. These permit quantitative analysis of sediment samples many months after an oil spill. 

Several soil-vapor monitoring techniques are currendy being used to define areas of volatile organic chemical contamination. These procedures usually involve the collection of representative samples of the soil gas for analysis of indicator compounds. Maps marked with concentration contours of these indicator compounds can be used to identify potential sources to delineate the contaminated area. Indicator compounds (usually the more volatile compounds) are selected for each specific situation. For gasoline contamination, the compounds are usually benzene, toluene, ethylbenzene, and total xylene (BTEX). In the case of a fuel oil spill, the most commonly used indicator is naphthalene. Some laboratories have adapted the laboratory procedures used for quality analysis of wellhead condensate (i.e., normal paraffins) to include light-end (<8 carbons) molecular analysis. 

Johnson, B.T Petty, J.D. Huckins, J.N. Lee, K. 2004, Hazard assessment of simulated oil spill on intertidal areas of the St. Lawrence River with SPMD-TOX. Environ. Toxicol. 19 329-335. K6ci, V. Ocelka, T. Kochankova, L. 2001a, SPMD—a modem proach to passive sampling. Vodni Hospodarstvi 51 331-332. 

Gulf Coast Petroleum Refinery. This project involved the cleannp of a crude oil spill in a wetlands area. Costs were estimated to be 2/ft of area treated. Treatment included emergency response mobilization, demobilization, sampling, laboratory analyses, and treatment (D17796C, p. 4). 

Many of PAHs are known to be mutagenic and/or carcinogenic (Neff, 1979). Coke production, combustion of fossil fuels, chemical production, and oil spills are the potential sources of PAHs. In recent studies on PAHs, these compounds were found to be one of the prevalent organic contaminants in South Korean sediments (Kim et al., 1999b Koh et al., 2002). However, compared to the reports on the classical POPs such as PCBs and OCPs, little is known about the degree of PAHs contamination in the South Korean environment, except for soil and sediments (Table 2.12). A total of 28 datasets reporting total concentrations of PAHs in South Korean samples, by sampling area, were found in the literature where total PAHs in air (n — 70), soil (n — 232), water (n — 25), and sediment (n — 281) were reported. 

Beside OCPs, studies on other POP chemicals in sediments have also been conducted. In 1992, we conducted a study (Ibrahim et al., 1996) on levels of PAHs in Langkawi Island when a major oil spill occurred in the vicinity. Due to quick and efficient recovery operations, minimal impact of the oil spill was experienced with the total PAHs found being in the range of 34-273 pg kg-1 which was slightly above the concentration of controlled samples. Contamination of PAHs, particularly in coastal sediments, was attributed to oil tankers carrying crude oil from the Middle East in the Straits of Malacca and the off-shore oil platform in the South China Sea (Zakaria et al., 2001). 

Reddy, C.M., Quinn, J.G., 1999. GC-MS analysis of total petroleum hydrocarbons and polycyclic aromatic hydrocarbons in seawater samples after the North Cape oil spill. Mar. Pollut. Bull. 38, 126-135. 

Environmental and Reservoir Observations. Evidence from the chemical analyses of samples from crude oil spills and petroleum reservoirs suggests that the OSC vary in susceptibility to metabolism under environmental conditions. Metabolism is slow and selective, and the observed variability is due to the microbial population, ambient conditions and physical/chemical properties of the petroleum. 

Garra and Muth [24] characterised cmde, semi-refined and refined oils by gas chromatography. Separation followed by dual-response detection (flame ionisation for hydrocarbons and flame photometric detection for sulphur-containing compounds) was used as a basis for identifying oil samples. By examination of chromatograms, it was shown that refinery oils can be artificially weathered so that the source of oil spills can be determined. 

Rasmussen [495] has described gas chromatography methods for the identification of hydrocarbon oil spills. The spill samples are analysed on a 30.5m Dexsil-300 support coated open tube (SCOT) column to obtain maximum resolution. 

I Tracking of Oil Spills on Water Surveillance of Other Types of Spills Monitoring of Atmospheric and Environmental Conditions Sampling/Monitoring of Environmental Contamination Documentation of Activities during Emergencies... 

Mansuy L, Philp RP, Allen J (1997) Source identification of oil spills based on the isotopic composition of individual components in weathered oil samples. Environ Sci Technol 31 3417-3425... 

A further interesting aspect of heterogeneous photochemistry concerns oil spilled at sea near land, which is subjected to environmental effects such as evaporation, dissolution, photo oxidation, dispersion into the water column and biodegradation. The fate of heavy fuel oil stranded on rock was studied under different environmental conditions [87]. Samples exposed to full or reflected sunlight showed depletion of the larger and more alkylated aromatic hydrocarbons and formation of resins, in agreement with reported laboratory studies on thin films of oil. 

The discussion above focuses on petroleum hydrocarbons from oil spills, representing just one source of contamination. Marine contaminant surveys are conducted not just in response to tanker accidents, but routinely as a means to assess the quality of the marine environment. Although analytical difficulties with environmental samples persist and... 

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