Hydrocarbons from sea water

EXTRACTION AND ANALYSIS OF HYDROCARBONS FROM SEA WATER AND SEDIMENTS 

Techniques for the collection, storage, conservation, isolation and analysis of hydrocarbons from sea water and sediment are briefly described below and illustrated in Fig. 1. Typical data and descriptions of the techniques employed for the analysis of natural or mixed hydrocarbons firom sea water or sea surface microlayers from coastal and open sea areas considered to be relatively unpolluted, are given chronologically in Table I. 

Collection of samples of the sea surface microlayer can be performed from a rowed dinghy, at least one mile upwind of the ship. The method usually used is the metallic steel screen technique described by Garrett (1965). 

Surface samples can be taken with a stainless steel bucket from the windward side, under way at low speed, just before arrival on station. An uncontaminated sea water line, continuously flushed, is also a source for surface samples. 

Profile samples are generally collected with bottles using conventional 

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Fig. 1. Example of extraction, separation and analysis of hydrocarbons from sea water and sediments.

Typical data on dissolved and particulate hydrocarbons from sea water a chronological table... 

Extraction of dissolved hydrocarbons from sea water Most of the methods used are based on the liquid—liquid extraction of lipids by a solvent various solvents such as CH2CI2, CHCI3, CQ4, nCeHn, nCsHi2, petroleum ether and ethyl acetate have been tested for the recovery and employed (Table I). Recovery of a synthetic mixture of saturated hydrocarbons by extraction with petroleum ether and ethyl acetate is about 97% (Jeffrey et al., 1964). Blumer (1970) demonstrated that the extraction of dissolved lipids at pH 2 using pentane as the solvent was quantitative after four extraction steps. Parker et al. (1972), using a technique for the continuous extraction from sea water with hexane, found in control experi-... 

Walker et al. [84] examined several methods and solvents for use in the extraction of petroleum hydrocarbons from estuarine water and sediments, during an in situ study of petroleum degradation in sea water. The use of... 

Walker et al. [114] examined several methods and solvents for use in the extraction of petroleum hydrocarbons from estuarine water and sediments, during an in situ study of petroleum degradation in sea water. The use of hexane, benzene and chloroform as solvents is discussed and compared, and quantitative and qualitative differences were determined by analysis using low-resolution computerised mass spectrometry. Using these data, and data obtained following the total recovery of petroleum hydrocarbons, it is concluded that benzene or benzene-methanol azeotrope are the most effective solvents. 

Particulate hydrocarbons may be recovered from sea water by filtration with gentle vacuum or moderate over pressure to avoid rupture of cell material. Since lipid molecules, such as fatty acids have been shown to be adsorbed by membrane (0.45-jum) filters (Quinn and Meyers, 1971), it is recommended to use fibreglass filters (e.g. Whatman GF/C, 1 jam or GF/F, 0.7 (im), which can be combusted and pre-extracted with a solvent. The filtration techniques employed by various workers differ depending on the sample volumes involved (see Table I). 

Another promising method involves trapping non-volatile hydrocarbons on a Bondapak Ci8 packed column as described by May et al. (1975). The recovery from sea water of internal aromatic standards is 92 2% for phenanthrene, 78 17% for pyrene and 58 12% for benzo(a)pyrene. 

The preliminary extraction of hydrocarbons and other compounds from sea water or sediment is followed by the isolation of hydrocarbons from the extract. At this stage a variety of analytical methods may be applied to analyse for total hydrocarbons or selected fractions. 

Deviations from Pick s law become more pronounced at high temperatures and are often found for materials immersed in certain liquids, notably solvents, hydrocarbons and sea water. However, in many laminates, even where moisture transport is by a non-Fickian process, the results obtained using Pick s equations together with appropriate apparent D and apparent values are not very different from the observed behaviour. 

In terms of fish tainting from pollution. Vale et al. [18] and Shipton et al. [19] have reported finding a kerosene taint in mullet. The tainted mullet were found to contain high levels of hydrocarbons from polluted waters. Bemelmans and den Braber [20] reported an iodine-like taint in herring from the Baltic Sea. They traced this taint to o-bromophenol. While the source of the o-bromophenol was not determined, it is possible that it came from industrial water pollution. 

Leoni [366] observed that in the extraction preconcentration of organochlo-rine insecticides and PCB s from surface and coastal waters in the presence of other pollutants such as oil, surface active substances, etc., the results obtained with an absorption column of Tenax-Celite are equivalent to those obtained with the continuous liquid-liquid extraction technique. For non-saline waters that contain solids in suspension that absorb pesticides, it may be necessary to filter the water before extraction with Tenax and then to extract the suspended solids separately. Analyses of river and estuarine sea waters, filtered before extraction, showed the effectiveness of Tenax, and the extracts obtained for pesticide analysis prove to be much less contaminated by interfering substances than corresponding extracts obtained by the liquid-liquid technique. Leoni et al. [365] showed that for the extraction of organic micro pollutants such as pesticides and aromatic polycyclic hydrocarbons from waters, the recoveries of these substances from unpolluted waters (mineral and potable waters) when added at the level of 1 xg/l averaged 90%. 

Chemical radicals—such as hydroxyl, peroxyhydroxyl, and various alkyl and aryl species—have either been observed in laboratory studies or have been postulated as photochemical reaction intermediates. Atmospheric photochemical reactions also result in the formation of finely divided suspended particles (secondary aerosols), which create atmospheric haze. Their chemical content is enriched with sulfates (from sulfur dioxide), nitrates (from nitrogen dioxide, nitric oxide, and peroxyacylnitrates), ammonium (from ammonia), chloride (from sea salt), water, and oxygenated, sulfiirated, and nitrated organic compounds (from chemical combination of ozone and oxygen with hydrocarbon, sulfur oxide, and nitrogen oxide fragments). ... 

The SSMAE allows for estimation of the flow of pollutants between the different water areas of the Arctic Basin. For example, the transport of heavy metals and oil hydrocarbons from the Barents Sea to the Kara Sea is 631 kg yr 1 and 473kgyr 1, respectively. The total flow of pollutants from the Russian coastline to Alaska varies in Table 6.10 between 0.3% and 0.9% of the initial flow. As is evident from curves 3 and 4 of Figure 6.8, the flow of the Ob and Yenisey Rivers has practically no influence on the pollution level of Arctic waters near Alaska. This effect does not change over time. 

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