An investigation was carried out into the PAH chemical contamination
resulting from the “Erika” tanker fuel spillage of December 1999 along the French
coast of the Bay of Biscay. A qualitative and quantitative assessment was
conducted of this contamination in water, suspended particulate matter,
sediments, and in intertidal molluscs. The chemical composition of PAHs in
pre-spill and post-spill samples was determined and used to distinguish the
“Erika's” fuel as the source of PAHs in the coastal environment of the Bay of Biscay.
Changes in concentrations of PAHs were also assessed. The GC-MS analysis
made it possible to identify and quantify parent unsubstituted PAHs,
alkyl-substituted PAHs (C-PAH) and sulfur heterocycle unsubstituted and
alkyl substituted compounds (SPAH and C-SPAH).
The results of this study demonstrated that heavily oil-contaminated
shorelines, including beaches, rocky coasts as well as sandy sediments
apparently became reservoirs of spilled fuel and these continued to
contaminate seawater, suspended particulate matter and mussels with PAHs.
These conclusions were borne out by the following observations: (1) the
pattern changes in PAH composition after the “Erika” oil spill were consistent in
all contaminated compartments (water, suspended particulate matter SPM,
intertidal sediments and molluscs), (2) the compositional patterns of PAHs
after the “Erika” oil spill in contaminated water, SPM, intertidal sediments and
molluscs constantly included alkyl-substituted phenanthrenes, pyrenes,
chrysenes and sulfur heterocycle compounds in higher relative abundances
than those in the pre-spill samples of these compartments, (3) the relative
abundances of different suites of PAHs at contaminated sites were similar to
those of weathered “Erika” fuel, (4) consistent and visible temporal decline in
concentrations for water, SPM and molluscs, (5) the geographical contiguity
of the stations with high concentrations of PAHs in molluscs matched the
extent of the shoreline contamination by the spilled fuel.
The increase in the contamination levels before and after the spill,
together with the significant change in the pattern of PAH composition
provide evidence of the intense and long-term chemical contamination of the
“Erika's” fuel and of the damage to natural marine resources resulting from such
contamination by toxic oil components.