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As the most persistent aromatic compounds, the P and DBT compounds
(mainly C 2 , C 3 , and C 4 ) mark AMOCO CADIZ oil in tissue (oysters) and
sediments through mid-1980. The final (June 1981) sediment sampling
failed to reveal significant P and DBT levels in any of the stations.
The latest (1981) status of the oyster P and DBT levels is unknown.
However, through most of the data to
compounds dominate the f
2 distribution.
C3P/C3DBT,
be discussed, the P and DBT
The ratios of C 2 P/C 2DBT and
used by Overton et al. (1981)
spill remain in the 0.3-0.6 range. The
to differentiate oils, in this
use of this ratio is discussed
in the text.
3.1.3 Residues in Tissues
As stated, the P and DBT compounds are most readily associated
with oyster tissue samples in the two-year period following the spillage.
The branched alkanes (isoprenoids) also persist throughout this
period.
3.1.4 Environmental Variability
A major question in oil spill studies and for that matter environmental
studies in general is the question of patchiness of pollutant
distributions and the variability due to patchiness in chemical measurements.
To shed some light on this subject two sets of measurements
are available. Two principal investigators (Atlas and Ward) obtained
samples at the same time and location in several instances, Atlas
sampling the top 3-5 cm, Ward sampling an entire sediment core but
subdividing the top 0-5 cm section. The total hydrocarbon values
(Table 4) reveal wide disparities where contamination is very heavy
(pooling of oil in the lie Grande) but reasonable to excellent agreement
in most cases. (Note also that additional replicate analyses are
available for sediment samples in Section 3.2 as well).
TABLE 4. Analysis of sampling variability.
STATION
TOTAL HYDROCARBONS (f L + f 2 ) (ug/g)