104
Marine Sediments
a pristine reference area. Over 90 nitrogen-containing aromatics were identified in the
sediments from Eagle Harbour and in the creosote oil. The total nitrogen-containing
aromatics concentration in Eagle Harbour sediments ranged from 200 Ilg to 1 200 mg
kg- I sediment (dry weight). Primarily, three ring and four ring nitrogen-containing
aromatics were identified, thought to originate from a wood creosoting facility on the
shores of the harbour.
4.4.4
Polyaromatic Hydrocarbons
Dunn and Stich [305, 306] and Dunn have described a monitoring procedure for
PAHs, particularly benzo[a]pyrene in marine sediments. The procedures involve
extraction and purification of hydrocarbon fractions from the sediments and determination of compounds by thin-layer chromatography and fluorimetry, or gas chromatography. In this procedure, the sediment was refluxed with ethanolic potassium
hydroxide, then filtered and the filtrate extracted with isooctane. The isooctane
extract was cleaned up on a florisil column, then the polyaromatic hydrocarbons were
extracted from the isoactive extract with pure dimethyl sulphoxide. The latter phase
was contacted with water, then extracted with isooctane to recover polyaromatic
hydrocarbons. The overall recovery of polyaromatic hydrocarbons in this extract by
fluorescence spectroscopy was 50-70 %.
4.4.5
Humic and Fulvic Acids
Pontanen and Morris [307] compared the structure of humic acids from marine
sediments and degraded diatoms by infrared and C13 and proton NMR spectroscopy.
Samples of marine sediments taken from the Peru continental shelf were extracted
with water, sodium hydroxide (0.05 moll-I) and sodium pyrophosphate (0.05 moll-I)
under an atmosphere of nitrogen and fractioned by ultrafiltration. Humic acids of
molecular weight 300 000 and above were examined. Diatoms were collected from
ecosystem bags in Loch Ewe, UK. Highly branched aliphatic compounds formed the
major fraction of the acids. Carbohydrates, and, to a lesser extent, aromatic compounds, and carbonyl, ether, alcohol, and amino groups were found in marine humic
acids. The structure of the marine and algal humic acids were similar, and there was
evidence that certain sediment humic acids originated from planktonic debris.
Hayase [308] measured the fluorescence and absorption spectra of humic acid and
fulvic acid in sediment collected from Tokyo Bay, at 20°C and pH 8. The maximal
excitation and emission wavelengths for humic acid were longer than those for fulvic
acid, independent of molecular weight, and could therefore be used to differentiate
between humic acid and fulvic acid in marine deposits. Smaller molecules showed
greater fluorescence than larger molecules. Fluorescence intensity per weight concentrations unit increased for humic acid, and decreased for fulvic acid, with increase in
absorption coefficient.
Raspor et al. [309] examined humic acids isolated from marine deposits in the
Adriatic Sea and the Norwegian Sea, and humic acid and fulvic acid isolated from an
estuarine sediment from Borneo. They presented data on their elementary composi-
Marine Sediments
a pristine reference area. Over 90 nitrogen-containing aromatics were identified in the
sediments from Eagle Harbour and in the creosote oil. The total nitrogen-containing
aromatics concentration in Eagle Harbour sediments ranged from 200 Ilg to 1 200 mg
kg- I sediment (dry weight). Primarily, three ring and four ring nitrogen-containing
aromatics were identified, thought to originate from a wood creosoting facility on the
shores of the harbour.
4.4.4
Polyaromatic Hydrocarbons
Dunn and Stich [305, 306] and Dunn have described a monitoring procedure for
PAHs, particularly benzo[a]pyrene in marine sediments. The procedures involve
extraction and purification of hydrocarbon fractions from the sediments and determination of compounds by thin-layer chromatography and fluorimetry, or gas chromatography. In this procedure, the sediment was refluxed with ethanolic potassium
hydroxide, then filtered and the filtrate extracted with isooctane. The isooctane
extract was cleaned up on a florisil column, then the polyaromatic hydrocarbons were
extracted from the isoactive extract with pure dimethyl sulphoxide. The latter phase
was contacted with water, then extracted with isooctane to recover polyaromatic
hydrocarbons. The overall recovery of polyaromatic hydrocarbons in this extract by
fluorescence spectroscopy was 50-70 %.
4.4.5
Humic and Fulvic Acids
Pontanen and Morris [307] compared the structure of humic acids from marine
sediments and degraded diatoms by infrared and C13 and proton NMR spectroscopy.
Samples of marine sediments taken from the Peru continental shelf were extracted
with water, sodium hydroxide (0.05 moll-I) and sodium pyrophosphate (0.05 moll-I)
under an atmosphere of nitrogen and fractioned by ultrafiltration. Humic acids of
molecular weight 300 000 and above were examined. Diatoms were collected from
ecosystem bags in Loch Ewe, UK. Highly branched aliphatic compounds formed the
major fraction of the acids. Carbohydrates, and, to a lesser extent, aromatic compounds, and carbonyl, ether, alcohol, and amino groups were found in marine humic
acids. The structure of the marine and algal humic acids were similar, and there was
evidence that certain sediment humic acids originated from planktonic debris.
Hayase [308] measured the fluorescence and absorption spectra of humic acid and
fulvic acid in sediment collected from Tokyo Bay, at 20°C and pH 8. The maximal
excitation and emission wavelengths for humic acid were longer than those for fulvic
acid, independent of molecular weight, and could therefore be used to differentiate
between humic acid and fulvic acid in marine deposits. Smaller molecules showed
greater fluorescence than larger molecules. Fluorescence intensity per weight concentrations unit increased for humic acid, and decreased for fulvic acid, with increase in
absorption coefficient.
Raspor et al. [309] examined humic acids isolated from marine deposits in the
Adriatic Sea and the Norwegian Sea, and humic acid and fulvic acid isolated from an
estuarine sediment from Borneo. They presented data on their elementary composi-