PARENT SESSION
5B The use of biomarkers for assessing ecosystem damage
9:00 AM to 7:00 PM, Wednesday, 09 May 2001

(W/MF144) Biomarker responses in bivalve molluscs exposed to model contaminants and in animals transplanted to metal-polluted sites.

Romero, Antonio¹, Rodriguez-Ortega, Manuel¹, Alhama, Jose¹, Rodriguez-Ariza, Antonio¹, Amezcua, Oscar², Marenco, Jose², Muņoz, Jose², Gomez-Ariza, Jose³, Lopez-Barea, Juan¹, ^{1 2 3}

ABSTRACT- Several biochemical pollution biomarkers were assayed in Andalusian littoral bivalves, the clam Chamaelea gallina and the mud-dwelling clam Scrobicularia plana, to correlate exposure to environmental contaminants with their biological effects. Biomarkers included the activities of key antioxidative (catalase, superoxide dismutase), ancillary antioxidative (glucose-6-P and isocitrate dehydrogenases, glutathione reductase), and other glutathione-related enzymes (glyoxalases I and II, glutathione-S-transferase), the glutathione content and redox status and the malonaldehyde level. C. gallina specimens were exposed in short-term microcosm assays to increasing concentrations in water of four model contaminants, CuCl₂, Aroclor 1254, tributyl-Sn, and Na₃AsO₄. Although somewhat increased biomarker responses were observed after exposure to copper and Aroclor, decreases were usually observed with tributyl-Sn and arsenate. Longer exposures in mesocosm experiments were also carried out at selected concentrations to compare contaminant uptake/release, biometric data and biomarker responses. Drastic responses to handling were observed in various biomarkers. Clean S. plana specimens were transplanted to a clean site and to the Guadalquivir estuary, possibly affected by the metals released in 1998 by the collapse of the tailings reservoir of Aznalcollar pyrite mine. Animals transplanted to the estuary showed a progressive uptake of As, Cd, Cu and Fe concomitant to a significant decrease in reduced glutathione content and parallel increase of malonaldehyde content. Thus, biochemical biomarkers analysed probably reflected the alteration of glutathione redox status and the generation of lipid peroxidation induced by metals. (Grant 1FD1997-0610)

Key words: bivalve molluscs, pollution biomarkers, oxidative stress, metals