Monitoring pollution in Tunisian coasts: application of a classification scale based on biochemical markers

Abstract

Over the past decade, molecular, biochemical and cellular markers have been extensively used in pollution monitoring of aquatic environments. Biochemical markers have been selected among early molecular events occurring in the toxicological mechanisms of main contaminants. This paper assesses the marine environment quality along the Tunisian coasts using a statistical approach. Clams (Ruditapes decussatus) were collected during the four seasons of 2003 on seven different sites from the Tunisian coasts. Oxidative stress was evaluated in gills using catalase activity (Cat), neutral lipids and malonedialdehyde accumulation. Glutathione S-transferase activity is related to the conjugation of organic compounds and was evaluated in both, gills and digestive glands. Acetylcholinesterase activity was evaluated as the biomarker of exposure to organophosphorous, carbamate pesticides and heavy metals. For each biomarker, a discriminatory factor was calculated and a response index allocated. For each site, a global response index was calculated as the sum of the response index of each biomarker. Discriminant analysis shows significant differences between sites and seasons compared with control sample. Faroua (site 1) and Menzel Jemile (site 2) seem to be the less polluted with respect to the other sites for all seasons. Gargour (site 6) shows the highest Multimarker Pollution Index during the four seasons, indicating higher contamination level.

Valuation of water pollution using enzymatic biomarkers in aquatic insects as bioindicators from El-Mansouriya stream, Dakahlia, Egypt

“…Moreover, activity inhibition was correlated with Zn, Cu and Cd accumulation in digestive gland and gills of treated clams (Kamel et al, 2012). Furthermore, pesticides, carbamates and heavy metals are known by their capacity to inhibit in vitro or in vivo, AChE activity (Galloway et al, 2004;Banni et al, 2005). Likewise, Lavado et al (2006) found that, when using AChE as neurotoxicity biomarker, AChE was strongly inhibited in the muscle of invertebrate sampled from a river highly polluted by organophosphorous, carbamates, and heavy metals.…”

Étude de l’effet du cadmium et du benzo[a]pyrène sur des enzymes de phase I et phase II de biotransformation chez le polychète Nereisdiversicolor

“…En effet, ce métal intervient par l'altération du métabolisme cellulaire tel que le transport transmembranaire, en bloquant des perméases impliquées dans les transports ioniques, particulièrement les pompes Na + /K + ATPase, et en provoquant une modification de la perméabilité des membranes et un déséquilibre de la balance ionique dans les cellules. Ce métal peut aussi altérer les fonctions mitochondriales, la stabilité lysosomale ou la réplication de l'ADN (WAISBERG et al, 2003) comme il peut aussi bloquer le site actif des enzymes (BANNI et al, 2005;GOERING et al, 1987;VIARENGO et al, 1990,). L'effet du cadmium a été aussi rapporté dans d'autres travaux, notamment de SANDRINI et al (2008) qui ont montré l'effet inhibiteur de ce métal sur l'activité supéroxyde dismutase SOD chez le polychète Laeonereis acuta.…”

Seasonal variation of oxidative stress biomarkers in clams Ruditapes decussatus sampled from Tunisian coastal areas

“…These bivalves are thus among the first exposed to terrestrial pollutants and consequently, environmental contamination occur earlier and is more accentuated than in mussels (Mytilus galloprovincialis) (Dellali et al 2001). Different exposure biomarkers have been studied in the clam Ruditapes decussatus in relation with heavy metal accumulation and organic compounds contamination (Banni et al 2005).…”