116
Estuarine Sediments
consumption. Typical silty sediments are characterized by a high oxygen uptake
whereas sandy sediments exhibit much lower values.
5.3
Organics
5.3.1
Polyaromatic Hydrocarbons
Readman et al. [343] used flame ionization capillary gas chromatography to determine polyaromatic hydrocarbons in extracts of rivers Mersey, Dee and Tamar estuary
sediments.
5.3.2
Hexachlorophene
Beller and Simoneit [344] studied the occurrence of hexachlorophene in extracts of
estuarine sediments taken from the Hudson River.
5.3.3
Polychlorinated Biphenyls, Chlorinated Insecticides, and Polyaromatic Hydrocarbons
Japenga et al. [345] determined polychlorinated biphenyls and chlorinated insecticides in river Elbe estuary sediments by a procedure in which the sediments were
pretreated with acetic acid, mixed with silica and Soxhlet-extracted with benzene /
hexane. Humic material and elemental sulphur were removed by passing the extract
through a chromatographic column containing basic alumina, on which sodium
sulphite and sodium hydroxide were adsorbed. Silica fractionation was followed by
gas chromatography to analyse chlorinated pesticides, polychlorinated biphenyls and
polyaromatic hydrocarbons. Recovery experiments with standard solutions gave recoveries of 90-102 %.
5.3.4
Chlorobenzenes
The isooctane extraction-gas chromatographic procedure [235] described in Sect.
3.4.4 has been applied to the determination of various (0.003-0.07 mg kg-I) chlorobenzenes in estuarine sediments.