196
Crustacea and Molluscs
metal pollution along parts of the conterminous US. Clean environments can be
defined, without actual measurements, within the water column. The US Mussel
Watch suggests a lead baseline of 1.0 mg kg-I, a west coast silver baseline (Mytilus
californianus) of 0.1 mg kg-I, and an east coast silver baseline (M. edulis) of
0.05 mg kg-I for organisms inhabiting a clean invironment.
Secondly, without expensive and time-consuming water analyses, natural phenomena influencing metal concentrations in seawater can be identified. Clearly, there is
a crucial importance for a confirmation of such hypotheses through actual water
studies. Without systematic surveys, elevated lead and cadmium might have been
interpreted as the result of a localized anthropogenic input rather than a natural
physical phenomenon such as upwelling.
Miscellaneous techniques. These include magnetron dc arc plasma [743], ion
chromatography [744], x-ray fluorescence spectroscopy, prompt activation analyses
and Neutron activation analysis [762].
8.2
Organics
8.2.1
Aliphatic Hydrocarbons
Gas Chromatography. Morgan [567] has described a gas chromatographic method for
the determination of Bunker C fuel oil in marine organisms at the 0.5 mg kg-I level.
Pentane-methanol extraction of tissues, using a blender, is followed by adsorption
chromatography.
Meyers [568] investigated the occurence of non-biogenic hydrocarbons in shrimps
occuring in the vicinity of offshore drilling and petroleum exploration in the Gulf of
Mexico. Samples were stored in glass at -20°C prior to analysis. The crushed sample was
treated with 0.5 N potassium hydroxide in 1:1 v Iv benzene: methanol, and, following the
addition of water, non-saponifiable lipids were extracted with petroleum ether. Column
chromatography using alumina over silica gel 50 I 50 separated saturated from unsaturated plus aromatic hydrocarbons. Gas-liquid chromatography with a flame ionization
detector was employed to resolve and to quantify the various components of each
hydrocarbon fraction. Both a non-polar column and a polar column were used. The
non-polar column was 4 m x 2.1 mm ID 3 % SP-2100 on 100 to 120-mesh Supelcoport
and was operated from 150 to 325°C at 4 K min-I using nitrogen carrier gas at 15 ml
min-I. The polar column was 2.5 mx2.1 mmID 10 % SP-I000 mesh Supe1coportand was
operated from 150 to 250°C at 8 K min-I using nitrogen at a flow rate of 15 ml min-I.
Although the organisms are from different orders of Crustacea, and were collected
during different sampling periods, their traces are very similar. Few normal alkanes
are found in any of the samples, and the saturated hydrocarbon compositions of these
animals appear to be composed mostly of branched compounds. The unsaturated
hydrocarbon compositions of these organisms also display a fairly simple pattern.
Usually four to six peaks dominate the chromatograms obtained from both non-polar
and polar columns. The major peaks of chromatograms of the saturated and unsatu-
Crustacea and Molluscs
metal pollution along parts of the conterminous US. Clean environments can be
defined, without actual measurements, within the water column. The US Mussel
Watch suggests a lead baseline of 1.0 mg kg-I, a west coast silver baseline (Mytilus
californianus) of 0.1 mg kg-I, and an east coast silver baseline (M. edulis) of
0.05 mg kg-I for organisms inhabiting a clean invironment.
Secondly, without expensive and time-consuming water analyses, natural phenomena influencing metal concentrations in seawater can be identified. Clearly, there is
a crucial importance for a confirmation of such hypotheses through actual water
studies. Without systematic surveys, elevated lead and cadmium might have been
interpreted as the result of a localized anthropogenic input rather than a natural
physical phenomenon such as upwelling.
Miscellaneous techniques. These include magnetron dc arc plasma [743], ion
chromatography [744], x-ray fluorescence spectroscopy, prompt activation analyses
and Neutron activation analysis [762].
8.2
Organics
8.2.1
Aliphatic Hydrocarbons
Gas Chromatography. Morgan [567] has described a gas chromatographic method for
the determination of Bunker C fuel oil in marine organisms at the 0.5 mg kg-I level.
Pentane-methanol extraction of tissues, using a blender, is followed by adsorption
chromatography.
Meyers [568] investigated the occurence of non-biogenic hydrocarbons in shrimps
occuring in the vicinity of offshore drilling and petroleum exploration in the Gulf of
Mexico. Samples were stored in glass at -20°C prior to analysis. The crushed sample was
treated with 0.5 N potassium hydroxide in 1:1 v Iv benzene: methanol, and, following the
addition of water, non-saponifiable lipids were extracted with petroleum ether. Column
chromatography using alumina over silica gel 50 I 50 separated saturated from unsaturated plus aromatic hydrocarbons. Gas-liquid chromatography with a flame ionization
detector was employed to resolve and to quantify the various components of each
hydrocarbon fraction. Both a non-polar column and a polar column were used. The
non-polar column was 4 m x 2.1 mm ID 3 % SP-2100 on 100 to 120-mesh Supelcoport
and was operated from 150 to 325°C at 4 K min-I using nitrogen carrier gas at 15 ml
min-I. The polar column was 2.5 mx2.1 mmID 10 % SP-I000 mesh Supe1coportand was
operated from 150 to 250°C at 8 K min-I using nitrogen at a flow rate of 15 ml min-I.
Although the organisms are from different orders of Crustacea, and were collected
during different sampling periods, their traces are very similar. Few normal alkanes
are found in any of the samples, and the saturated hydrocarbon compositions of these
animals appear to be composed mostly of branched compounds. The unsaturated
hydrocarbon compositions of these organisms also display a fairly simple pattern.
Usually four to six peaks dominate the chromatograms obtained from both non-polar
and polar columns. The major peaks of chromatograms of the saturated and unsatu-