Effects of sewage pollution on growth and oxidative balance in the freshwater clam Diplodon chilensis

• SABATINI S., ROCCHETTA I., LUQUET C.M., GUIDO M., RÍOS DE MOLINA, M.C.

Montevideo, Uruguay

Congreso; Congreso VIII SETAC LA; 2007

The effect of chronic exposure to Escherichia coli on morphometrical parameters, different antioxidant defenses, lipid peroxidation and protein oxidation has been studied in digestive gland of the freshwater clam Diplodon chilensis in the laboratory during six weeks. In, a parallel field study, we evaluated morphometrical and oxidative stress parameters in digestive glands of clams collected from a sewage polluted area (SMA) and from a pristine area (control). In the laboratory D. chilensis was able to filter bacteria at high concentrations with a clearing rate of 0.510 ± 0.036 L/h per gram of dry soft tissue mass. The digestive gland mass to shell length ratio (DGM/SL), reduced glutathione (GSH), lipid peroxidation, as concentration of thiobartituric acid reactive substances (TBARS), and Glutathione-S-transferase (GST) activity of clams fed with bacteria were significantly higher than those of control clams after the fourth week. Fecal bacteria in lake water samples were undetectable in the control, and higher than 24000 MPN (most probable number) /100 mL in SMA. DGM/SL was higher in SMA. No differences between sites were observed in total lipid and protein content, neither in superoxide dismutase activity. GSH content was higher in SMA, with no difference in the oxidized form. GST activity and MDA were significantly higher in SMA but protein oxidation was not affected.