Oxidative stress biomarkers and bioconcentration of reldan and roundup in the edible clam Ruditapes decussatus

摘要

Research on biomarkers as early indicators of perturbation in populations and individuals has received increasing interest during recent decades. We used bivalve molluscs (clams), which are known to be biomarkers sensitive to aquatic ecosystem pollution, in order to assess the effects of two organophosphorus pesticides; “Reldan” and “Roundup”. Biomarker responses of Ruditapes decussatus were assessed by measuring non-enzymatic (glutathione; GSH) and enzymatic (catalase; CAT) antioxidants in different tissues of the clam at different time intervals. Lipid peroxidation (LPO), protein carbonyl content, total proteins and total lipid as well as the activity of cholinesterase (ChE) were evaluated under laboratory conditions. The correlations between the different biomarkers and the bioaccumulation of the pesticides were studied. Reldan had the maximum oxidative stress-inducing potential in clam tissues leading to increased LPO and inhibition of the antioxidants. Gills showed the most sensitive response. R . decussatus is an excellent accumulator of chlorpyrifos A concentration of 824.0 mg/kg w.w was detected in the tissue after 60 days of Reldan exposure. Level of glyphosate increased to approximately 8×10³ mg/kg w.w as compared to background level by increasing the time of exposure to Roundup . It is concluded that measurement of several biomarkers in a single organism is useful. Protein carbonyl induction could be used as bioindicator of oxidative stress-inducing chemical contaminants in bivalves. Antioxidant defense components are sensitive parameters that could be useful biomarkers for the evaluation of contaminated aquatic ecosystems. Biomarker parameters, when complemented with chemical analysis of clam tissues, provide a powerful monitoring tool[ Acta Zoologica Sinica 53(5): 910–920, 2007].