Study on age-related bioaccumulation of some heavy metals in the soft tissue of rock oyster (Saccostrea cucullata) from Laft Port - Qeshm Island, Iran

Heavy metals widely enter into aquatic ecosystems, and cause various environmental problems due to bioaccumulation and biomagnification in food chains. The accumulation of heavy metals in bivalve tissues is affected by a number of intrinsic and extrinsic factors such as physiological conditions, growth, seasonal changes, pH, salinity, temperature, genera and age. The present study investigated the effects of age of the rock oyster Saccostrea cucullata on the accumulation of Ni, Cd and Pb in the Laft Port coast located on the Qeshm Island. 200 oysters were collected and their age was determined, then they were classified into four age categories and 15 oysters from each category were selected. Samples were dry digested and the metal concentrations were measured by an ICP-OES (PerkinElmer, USA) instrument. Results revealed that the accumulation of Ni and Pb in one year old oysters (immature) was more than those in mature oysters (two, three and four year old oysters). Significant differences were observed between concentrations of Ni and Pb in mature and immature oysters. The results suggested that aging has a negative effect on bioaccumulation of Ni and Pb in S. cucullata; while it has no effect on bioaccumulation of Cd.