VERTIMAR-2005
Symposium on Marine Accidental Oil Spills
Determination of chronic toxicity in sediments impacted by the
Prestige oil spill and in sediments affected by continuous spills
in the bay of Algeciras using C. maenas and R. philippinarum
Carmen MORALES-CASELLES, M. Laura MARTÍN-DÍAZ, M. Carmen SARASQUETE,
Inmaculada RIBA and Ángel DELVALLS
Instituto de Ciencias Marinas de Andalucía, CSIC, Facultad de Ciencias del Mar y Ambientales (Unidad
Asociada. Calidad Ambiental y Patológica) / Avda. República Saharaui s/n Apdo,40. Puerto Real 11510,
Cádiz, Spain.
ABSTRACT This study assess the biological response of two marine organisms exposed to contaminated
sediments impacted in different way by oil spills: sediments from the Galician Coast affected by the oil spill of the tanker
“Prestige” (November, 2002) and sediments from the Bay of Algeciras chronically impacted by the spills in the area. The
bioassay has a total exposure time of 28 days and was carried out with the shore crab Carcinus maenas and the clam
Ruditapes philipinarum. Different biomarkers of exposure (metallothioneins and EROD) and biomarkers of effect
(histopathology) were analyzed along the time. Results of mortality and the different biomarkers were linked with the
contaminant data providing useful information that was not provided in previous acute toxicity tests.
1. INTRODUCTION
In the present study two areas of the Spanish Coast affected by different spills were
selected to carry out a sublethal study about the quality of their sediments. The area of Galicia
was selected to assess the impact provoked on the sediments by the oil spill of the tanker
“Prestige” (November, 2002). Besides, the study was also performed with sediments originated
in the Bay of Algeciras which is impacted by spills of different contaminants, including
hydrocarbons, coming from the close industries.
Sediments from both coastal areas were collected, characterized and kept in cold no more
than one week until the beginning of the experiment. Beside, clean sediment from the bay of
Cádiz was collected to use as a negative control. Two organisms with different feeding habits
were selected for the sublethal bioassays: the clam Ruditappes philipinarum and the crab
Carcinus maenas. Ruditappes philipinarum was provided from an aquaculture farm whereas
Carcinus maenas was obtained from a clean site in the bay of Cádiz. The organisms were
acclimatized in the laboratory previously to the test; after that the organisms were placed in
aquariums and exposed to the sediment samples from both different areas. Marine water was
provided and physico chemical conditions were controlled.
The bioassays implies 28 days of exposure period and every week samples of tissues of the
organisms were collected and separated for the different treatments and the determination of
biomarkers. Metallothioneins induction and EROD activity were selected as the biomarkers of
exposure, whereas histopathology was used as a biomarker of effect.
2. RESULTS AND DISCUSSION
Previous studies have shown that there was not an important toxic effect in different marine
organisms (clams and microalga) exposed to samples of the sediments and their elutriates
associated to the spill caused by the tanker “Prestige” (Mariño-Balsa et. al, 2002). However, two
years after the oil spill, the results obtained in this sediment toxicity have detected positive
responses in sediments from the same area by using subletal bioassays. Sediments from the
Bay of Algeciras have also presented sublethal toxicity to the organisms exposed.
The comparison between chemical analysis and the different toxic response (biomarkers of
exposure and of effect at different levels) of different organisms is a useful tool to determine the
quality of the studied sediments. It has been proved the importance of the use of chronic
bioassays which provide long-term information of the effects of the exposure to a toxic
compound, since a compound can no reflect a considerable acute toxicity but it is able to
produce lesions at different levels to the organism exposed.
VERTIMAR-2005
Symposium on Marine Accidental Oil Spills
REFERENCES
Mariño-Balsa, J.C., Pérez, P., Estévez-Blanco, P., Saco-Álvarez, L., Fernández, E., Beiras, R.
(2002). Assessment of the toxicity of sediment and seawater polluted by the Prestige fuel
spill using bioassays with clams ( Venerupis pollastra, Tappes decussatus and Venerupis
rhomboideus) and the microalga Skeletonema costatum. Cienc. Mar., 29 (1): 115-122.