Chemical, biochemical and cellular responses in the digestive gland of themussel Mytilus galloprovincialis from the Spanish Mediterranean coast

Mussels (Mytilus galloprovincialis) were sampled in March 1996 from five st ations along the Western Mediterranean coast (Barcelona, Ebro Delta, Albora ya, Cullera, Denia) corresponding to urban, industrial and agricultural are as. Different biochemical and cellular markers were determined in the musse ls in order to assess the effects and/or exposure to pollutants. The cytoch rome P450 system, acetylcholinesterase and metallothioneins were among the biochemical markers selected for the study. Histochemical analysis of beta -glucuronidase and catalase activity were performed as marker enzymes for l ysosomes and peroxisomes. Chemical analyses indicated that mussels from Bar celona and Denia as highly exposed to polycyclic aromatic hydrocarbons (PAH s) (1.8- 2.7 mug g(1) w.w. against 0.02-0.10 mug g(1) w.w.), and polychlori nated biphenyls (PCBs) (132-260 ng g(1) w.w. against 8-24 ng g(1) w.w.). Th is was in agreement with changes in lysosome structure and higher number of peroxisomes in those organisms. High levels of metals (particularly Cr and Cu) were recorded in the digestive gland of Alboraya mussels, which also h ad elevated metallothionein content (28 nmol g(1) w.w.) in comparison with the other stations (15-20 nmol g(1) w.w.). Benzo(a) pyrene hydroxylase (BPH ) activity indicated Cullera and Barcelona as possibly polluted sites. The results support the usefulness of the biomarker approach to assess and diag nose environmental pollution. The use of a battery of biomarkers at differe nt levels of biological organization coupled with chemical analysis is high lighted.