Biosorption and bioaccumulation of heavy metals by rock oyster Saccostrea cucullata in the Persian Gulf

Abstract

Effective treatments of industrial waste streams and toxic spills containing heavy metals related with rapid removal of metal ions at high concentrations. Influences of clearance and absorption rates on two heavy metals (copper and cadmium) by saccustrea cucullata originated from mangrove ecosystem in the Northern Persian Gulf were investigated. Specimens were collected from sub-tidal band during neap tide; groups of 15 individual were placed in 1.5 L containers (2-liter volume), which were immersed in the water. After the acclimation time (i.e. the regulation of filtration activity caused by manipulation and any other sources), specific clearance and absorption performances were measured during alternation of stagnation and flow positions. Temperature, salinity and particle concentrations were maintained. The clearance rate is affected by the amount of cadmium (from 1.69 to 0.04 ml min/g/h AFDW) and copper (from 2.16 ml to 0.42 ml min/g/h AFDW). Although the clearance rate was significantly reduced, live oysters reduced the amount of cadmium and copper from 150 and 200 µg/l to 118.68 and 133.30 µg/l respectively. Oyster had the different clearance rates toward copper and cadmium when simultaneously introduced. The dead shells also had a good ability to reduce the metal condensation. According to the results it can be concluded that Sacostrea cucullata can be used as biofilters with good clearance ability.