Oil in the Sea Inputs, Fates, and Effects (1985) / Chapter Skim
Currently Skimming:
Part A: Chemical Methods
Part A: Chemical Methods
Pages 94-134
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From page 94... ...
choosing the method (s) that will satisfactorily solve the analytical problem at hand; for example, gross levels of hydrocarbons in tissues as determined by nonspecific measurements such as ultraviolet fluorescence have minimal use when the problem is to distinguish between chronic background hydrocarbon pollution of combustion origin, chronic petroleum pollution, biogenic hydrocarbon inputs, and additions of petroleum hydrocarbons from a recent oil spill; and (b)
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From page 95... ...
Of primary concern in both petroleum hydrocarbon baseline and oil spill samplings is the avoidance of sample contamination and cross contamination.
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From page 96... ...
in oil spill studies. Thompson and Eglinton (1978b)
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From page 97... ...
. Use of the various available devices for obtaining seawater samples for petroleum hydrocarbon determinations has been reviewed recently by D.R.
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From page 98... ...
Dissolved and particulate size fractionations are important in discerning the fate and pathways of biological uptake of spilled oil (Zurcher and Thuer, 1978; Boehm and Fiest, 1980b) and distribution of petroleum hydrocarbons in seawater in nonspill studies (Goutz and Saliot, 1980; Boehm, 1980a)
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From page 99... ...
ASTM Method D 3325-78 presents a standard method for storing waterborne oil samples. The effects of long term (months to years)
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From page 100... ...
Analytical Methods Physical and chemical information should be obtained as soon as possible after the spill occurs. Field Information The existence, extent, and mapping of subsurface oil concentrations may be acquired during spill events through the use of in situ (towed)
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From page 101... ...
Laboratory Information {Long Time Frame: Weeks to Months) Techniques of petroleum character ization include those that der ive detailed compositional information as well as those that obtain information used to match waterborne oils with suspected cargoes through TR (infrared spectrometry)
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From page 102... ...
Figure 3-1 illustrates various analytical options for environmental samples. The proper choices of separation and analytical techniques are at the heart of environmental petroleum hydrocarbon chemistry.
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From page 103... ...
levels of sophistication. Recently the ACS Subcommittee on Environmental Analytical Chemistry published its "Guidelines on Data Acqui sition and Data Quality Evaluation,~ which expressed three interwoven strategies of modern trace analysis: (1)
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From page 104... ...
Hydrocarbons Sediments Several different solvent extraction methods are commonly used for the extraction of petroleum hydrocarbons from sediments. No standard method exists, but most methods involve the combined use of polar and nonpolar solvents to effect an efficient extraction of organic matter.
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From page 105... ...
Tissues Petroleum hydrocarbons present in marine plants and animals include both those loosely bound to the tissue matrix and those occurring intracellularly. Several methods have been utilized extensively to extract these compounds.
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. Seawater The prec ise choice of extraction techniques used to isolate petroleum hydrocarbons from seawater depends on the nature of the sampling de~rice used ~ see Sampl ing and Sample Preservation section)
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From page 107... ...
This is especially a problem for compounds in the Clo-C13 molecular weight range, and most analysts report data for compounds of molecular weight C14 or Cls and greater. Sample Cleanup and Fractionation In order to increase the precision and discrimination of all analytical techniques, samples may be treated by any one or a series of several types of sample cleanup and fractionation techniques which fall into three basic categories: polarity, size, and chemical separations.
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From page 109... ...
pr for to any fractionation or analytical steps to conver t solvent soluble waxes and glycer ides to their fatty acid salts and alcohols. The polar lipids can then be partitioned into water, leaving a less complex extract containing nonsaponifiable lipids, which include the petroleum hydrocarbons.
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From page 110... ...
A variety of analytical methods is available to analyze the levels and composition of hydrocarbons in the solvent extract of an environmental sample. Since the mid- to late-1960s, investigators have realized that techniques to measure petroleum hydrocarbons (PHC)
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From page 111... ...
, and in which more detailed compositional information is also obtained. Infrared Spectrometry Infrared spectrometry is well suited as an analytical technique for the identif ication of waterborne oil and match i ng with suspected cargos of crudes and fuel oils ~ i .
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From page 112... ...
n These measurements are better suited than the oil and grease (i.e., unfractionated) IR data, but in nonspill situations they still suffer greatly from difficulties of interpretation and accurate quantification of petroleum hydrocarbons.
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From page 113... ...
. The fluorescence spectra of crude oils and petroleum products have been under intense investigation in recent years (John and Soutar, 1976; ASTM Method D 3650-78; U.S.
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, with the caveat that accuracy and more detailed compositional information are sacrificed. Baseline seawater measurements generally achieve estimated concentrations in crude oil equivalents (Levy and ~offatt, 1975; Law, 1981~.
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/ l \ I J 400 I , I I I I L I Ring 2 Rings 3,4 Rings 450 250 nm 300 350 5 Rings FIGURE 3-5 Representative synchronous fluorescence spectra of water samples collected near the Ixtoc I blowout.
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From page 116... ...
HPLC techniques have advanced rapidly in the past 5 years. Although not even discussed in the 1975 NRC report, HPLC is now a major emerging method for the analysis of aromatic hydrocarbons, labile metabolites, and petroleum-derived nitrogen bases in marine samples in many cases (Colin et al., 1981; Wakeham et al., 1981; R.F.
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Gas Chromatography (GC ~ Great advances in GC column methodology have been respond ible for a vastly increased abil ity to analyze nanogram levels of individual hydrocarbons routinely in complex environmental samples and to discern
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From page 118... ...
Stainless steel and glass columns packed with a liquid phase adsorbed onto a solid support phase have given way to stainless steel, borosilicate glass, and fused silica glass capillary columns in which the inter for walls of the columns are coated directly with a liquid phase or coated with a support phase on which the liquid phase is bonded (Jennings, 1980 ~ . Increased resolution of complex hydrocarbon mixtures has resulted.
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From page 119... ...
Lee et al., 1979) and comparing with those of known compounds, (3 ~ coin jecting a sample wi th standards, or (4 ~ using supplemental analytical equipment and techniques (see Gas Chromatography/Mass Spectrometry section)
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, are the most powerful tools available to confirm the identity of and to quantify trace levels of individual petroleum hydrocarbon components in environmental samples. The identity of an unknown compound can be determined by matching the compound' s mass spectrum with that of the pure compound, either manually or via computerassisted mass spectral library searches and probability-based matches.
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From page 121... ...
of electron impact results in a high degree of fragmentation of nonaromatic hydrocarbons. CI, using methane as the ionizing gas, results in the preservation of the molecular ion (molecular weight)
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From page 122... ...
spectroscopy has been used to examine the relative molecular composition of petroleum constituents and fractions (Petrakis et al., 1980; Petrakis and Edelheit, 1979~. Low-Molecular-Weight Hydrocarbons: Analytical Methods Hydrocarbons in the Cl-Clo range are not amenable to routine solvent extraction techniques.
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From page 123... ...
PETROLEUM HYDROCARBON INTERC=IB~TION/IN=~~I SON PR=~S Interlaboratory intercalibration programs of various types have been undertaken with national and international scopes. The intent of these studies has been mainly to examine the variability of analytical results between labor ator ies, aid in the evaluation and compar isons of environmental data sets, evaluate the relative efficacy of different methodologies, and improve analytical methods so as to reduce interlaboratory discrepancies in data.
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From page 124... ...
Bearing in mind that there is no fright answer" in such exercises using environmental samples, a group of laboratories in the United States has obtained generally tightly grouped results based on GC2 {and GC2/MS) determined alkane and polynuclear aromatic hydrocarbon levels in sediments (MacLeod et al., 1981a)
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From page 128... ...
the location within the analytical technique for discrepancy. Laboratories should be urged to participate in intercalzbration programs in a nonthreatening atmosphere at the start of the environmental chemistry program, to enable the refinement of analytical techniques so as to achieve results within a determined statistical range.
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From page 129... ...
reviews the types of remote sensing devices and the false alarms g iven by each. Passive microwave systems measure radiation waves naturally emitted or reflected by the sea surface.
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From page 130... ...
. Depolarization occurs at the sea surface, and the two wavelengths are backscattered differentially.
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From page 131... ...
\ MONITORING FOR PETROLEUM HYDROCARBONS The success of any monitor ing program depends on the proper selection of environmental parameters to be measured, the proper choice of analytical techniques to be used, the comparabil ity of analytical results over time and between labor ator ies, and the statistical validity of the measurements (i.e., what level of sampling and analytical effort will detect change) (Risebrough et al., 1980~.
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From page 132... ...
ICES monitoring programs, in existence since 1977, have focused on metal and organochlorine residues in sediments and several fish and invertebrate species. Petroleum hydrocarbon information is beginning to be derived from this program, mainly based on specified W /F analysis, but presumably to be complemented by high resolution techniques as well.
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From page 133... ...
Recommendations Quality Control and Intercomparison of Data The rapid increase in the number of analysts and the demand for larger sets of data require careful quality control and intercomparison of ~ ~ ~ ~ ~ ~ ~ ~~~~ NRC report. data, now even more than at the time of the 1975 We recommend that rigorous quality assurance protocols be integrated into the analysis of hydrocarbon and other fossil fuel compounds in environmental samples.
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From page 134... ...
This Is especially true in regard to inclusion of pyrogenic source hydrocarbons within the data for petroleum. Application of Analytical Methods We recommend the application of analytical methods with sufficient sensitivity and resolution to identify the various sources of input, e.g., high resolution glass capillary/gas chromatography/mass spectrometry/computer systems analysis or high performance liquid chromatography analysis coupled with mass spectrometry computer systems.
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