202
Crustacea and Molluscs
After fluorimetry, the amount of radioactive benzo(a)pyrene internal standard in
each sample was determined by scintillation counting. The recovery ofbenzo(a)pyrene was calculated by comparing the amount of radioactivity added at the beginning of
the digestion procedure with the amount recovered in the fluorimetry sample. The
amount of benzo( a )pyrene determined by fluorimetry was then corrected if necessary
for the contribution of radioactive tracer (this correction is negligible if the higher
specific activity 3H-benzo(a)pyrene is used), and the net amount of benzo(a)pyrene
originally present in the sample was then expressed as J,lg benzo(a)pyrene kg-I wet
weight of tissue or dry weight of sediment.
The overall recovery of benzo(a)pyrene was generally 60-80 % for tissue samples
(mussels, clams, oysters).
Estimation of precision of benzo(a)pyrene determinations in mussels at the 1020 ng kg-I level ranged from a standard deviation of 0.4 to 1.45. Shoreline mussel samples
had a mean benzo(a)pyrene content of 0.55 mg kg-I net weight with a standard deviation
of 0.11. Samples stored for 12 weeks at -10 °c showed no significant change in benzo(a)pyrene content, suggesting that this is an adequate method of sample storage.
Dunn and Stich [575] applied this method to sediment samples in the vicinity of a
sewage outfall, showing elevated levels of benzo(a)pyrene. Mussels (Mytilus edulis)
taken from the outer Vancouver harbour showed lower benzo(a)pyrene levels in the
summer than in the winter, perhaps a result of seasonal discharges of sewage and
storm drain water into the harbour. Elevated levels of benzo(a)pyrene in mussels,
growing near creosoted timbers or piling, suggested that creosote may be a significant
source of this substance in the marine environment. Direct evidence for this suggestion was obtained by comparison of gas chromatography promes of polycyclic
aromatic hydrocarbons isolated from mussels and from creosoted wood.
Uthe and Musal [577] carried out an intercomparison study on the determination
of polynuclear aromatic hydrocarbons in lobster. Intercomparative kits comprising
lobster digestive gland acetone powder and lobster digestive gland oil were sent to
participants in Europe, the USA, and Canada. The participants were requested to
measure a suite of nonalkylated polyaromatic hydrocarbons and to analyse each
material. The methods used were either liquid chromatography with UV absorptionfluorescence detection or gas chromatography-mass spectrometry on cleaned up
extracts. Intralaboratory relative standard deviations for polyaromatic hydrocarbon
concentrations in oil ranged from 4.3 to 24.1 %. Interlaboratory relative standard
deviation ranged from 39 to 96 %. Laboratories using gas chromatography-mass
spectrometry reported a greater number of compounds, whereas those using liquid
chromatography-ultraviolet spectroscopy reported higher concentrations.
Giam et al. [578] have reported on the uptake and depuration of benzopyrene,
hexachlorobenzene, and pentachlorophenol in marine organisms. Methods capable of
determining down to 0.2 ~g kg-I of these substances are discussed.
8.2.3
Chlorinated Aliphatic Compounds
Murray and Riley [579, 580] described gas chromatographic methods for the determination of trichloroethylene, tetrachloroethylene, chloroform, and carbon tetrachlori-
Crustacea and Molluscs
After fluorimetry, the amount of radioactive benzo(a)pyrene internal standard in
each sample was determined by scintillation counting. The recovery ofbenzo(a)pyrene was calculated by comparing the amount of radioactivity added at the beginning of
the digestion procedure with the amount recovered in the fluorimetry sample. The
amount of benzo( a )pyrene determined by fluorimetry was then corrected if necessary
for the contribution of radioactive tracer (this correction is negligible if the higher
specific activity 3H-benzo(a)pyrene is used), and the net amount of benzo(a)pyrene
originally present in the sample was then expressed as J,lg benzo(a)pyrene kg-I wet
weight of tissue or dry weight of sediment.
The overall recovery of benzo(a)pyrene was generally 60-80 % for tissue samples
(mussels, clams, oysters).
Estimation of precision of benzo(a)pyrene determinations in mussels at the 1020 ng kg-I level ranged from a standard deviation of 0.4 to 1.45. Shoreline mussel samples
had a mean benzo(a)pyrene content of 0.55 mg kg-I net weight with a standard deviation
of 0.11. Samples stored for 12 weeks at -10 °c showed no significant change in benzo(a)pyrene content, suggesting that this is an adequate method of sample storage.
Dunn and Stich [575] applied this method to sediment samples in the vicinity of a
sewage outfall, showing elevated levels of benzo(a)pyrene. Mussels (Mytilus edulis)
taken from the outer Vancouver harbour showed lower benzo(a)pyrene levels in the
summer than in the winter, perhaps a result of seasonal discharges of sewage and
storm drain water into the harbour. Elevated levels of benzo(a)pyrene in mussels,
growing near creosoted timbers or piling, suggested that creosote may be a significant
source of this substance in the marine environment. Direct evidence for this suggestion was obtained by comparison of gas chromatography promes of polycyclic
aromatic hydrocarbons isolated from mussels and from creosoted wood.
Uthe and Musal [577] carried out an intercomparison study on the determination
of polynuclear aromatic hydrocarbons in lobster. Intercomparative kits comprising
lobster digestive gland acetone powder and lobster digestive gland oil were sent to
participants in Europe, the USA, and Canada. The participants were requested to
measure a suite of nonalkylated polyaromatic hydrocarbons and to analyse each
material. The methods used were either liquid chromatography with UV absorptionfluorescence detection or gas chromatography-mass spectrometry on cleaned up
extracts. Intralaboratory relative standard deviations for polyaromatic hydrocarbon
concentrations in oil ranged from 4.3 to 24.1 %. Interlaboratory relative standard
deviation ranged from 39 to 96 %. Laboratories using gas chromatography-mass
spectrometry reported a greater number of compounds, whereas those using liquid
chromatography-ultraviolet spectroscopy reported higher concentrations.
Giam et al. [578] have reported on the uptake and depuration of benzopyrene,
hexachlorobenzene, and pentachlorophenol in marine organisms. Methods capable of
determining down to 0.2 ~g kg-I of these substances are discussed.
8.2.3
Chlorinated Aliphatic Compounds
Murray and Riley [579, 580] described gas chromatographic methods for the determination of trichloroethylene, tetrachloroethylene, chloroform, and carbon tetrachlori-