Abstract:Heavy metal contamination of the natural environment has always been a great concern, because of toxicity and non-biodegradability of the metals. Copper (Cu) is an abundant trace element found in a variety of rocks and minerals and has received much attention due to its widespread use, persistence in nature, tendency to accumulate in and toxicity to aquatic organisms. There are many documented physiological effects of waterborne Cu2+ exposure in a variety of shellfish species, but further research is needed to explain the relationship between Cu2+ and shellfish species. To study the toxicological effects of Cu2+ on mussel Mytilus coruscus, juvenile M. coruscus were exposed to aqueous solutions of Cu2+. Ninety-six-hour acute toxicity effect experiments and 7 days stress experiments were carried out. Biomarkers including superoxide dismutase (SOD), catalase (CAT), lipid peroxidation (LPO), and metallothioneins (MT) in gill and visceral mass were determined after seven days of exposure. Integrated biomarker response (IBR) was calculated by combining multiple biomarkers into a single value in order to assess the responses of different tissues. The acute toxicity experiments showed 1.55 mg/L to be the 96 h median lethal concentration in juvenile M. coruscus. The 7 days stress experimental results showed that the activity of biomarkers were inhibited by all test concentrations and each index hadits own variation trend.Biomarkers SOD and CAT showed activity in gill and visceral mass, MT content in the gill firstly increased and then tended to decrease later, while the MT content in visceral mass and MDA content in gill and visceral mass exhibited an upward tendency. IBR values exhibited an increase at first then tended to decrease later, the IBR value in the visceral mass was higher than that in the gill. Changes of biomarkers’ activity were related to different exposure concentrations. IBR analysis allowed good discrimination between the different exposure concentrations and might be a useful tool for the quantification of various biomarker responses induced by toxic chemicals.
