Author(s): Jihene Ghedira, Lassaad Chouba, Jos Alhama
Biological effects of pollutants were studied in Carcinus maenas crabs from 3 polluted sites (Bizerte, Teboulba, Gargour) along the Tunisian littoral zone using biochemical biomarkers. A metal contamination gradient was found, Bizerte standing out as the most metalpolluted area. Gargour animals nonetheless showed higher oxidative stress responses, such as gluta thione reductase and 6-phosphogluconate dehydrogenase activities, as well as malondi alde - hyde (MDA) levels in gills. The gills showed higher lipid peroxidation than did the digestive gland, in keeping with their respiratory role. Animals were also exposed for different periods to 2 model pollutants, cadmium and chlorpyriphos-ethyl. Although cadium induces oxidative stress, mainly in gills, thus increasing lipid peroxidation, principal-component analysis indicated that metal content in sediments and crabs from in-field monitoring does not fully correlate with oxidative stress biomarker responses. Catalase and MDA were the most sensitive biomarkers, and gills the most responsive organ. A lower catalase content in gills was linked to higher MDA levels.