Title : Trace metals bioaccumulation in oysters (Crassostrea gasar) from Fresco Lagoon (Côte d'Ivoire, West Africa)
Abstract:
For the human risk assessment associeted with a highly consummed oyster (Crassostrea gasar), the concentrations of seven trace metals (Pb, Cd, Ni, Cr, Co, Fe and Zn) were measured using an Atomic Absorption Spectrometer. Average values of physicochemical parameters were as follows : pH (7.1), salinity (10.09 ‰), temperature (22.7 °C), Total Disolved Solids (9.73 mg/L). Oysters’ shell lenghs ranged from 4.2 cm to 11.5 cm, and the average water contents from 78.42 to 85.10 %. The mean concentrations were 91.4, 12.31, 38.06, 1199.06, 8.26, 578.23 and 454.04 mg/kg dry weight for Pb, Cd, Ni, Cr, Co, Fe and Zn. Estimated Daily Intake (EDI) of trace metals was calculated by mean oysters ingestion rate as 6.0 x 10-3 kg/day and 12.0 x 10-3 kg/day, on the basis of 15 and 30 oysters’ consumption respectively for chlidren and adults. According to the Target Hazard Quotient (THQ) values, a carcinogic risk was observed for Pb (THQ > 4.0), Cd (THQ > 2.0) and Cr (THQ > 60.0), either for chlidren and adults. The Hazard Index (HI) was also calculated to assess the risk link to all of the seven trace metals. HI values ranged from 41.77 to 115.99 for chlidren and from 33.41 to 92.75 for adults. These highest HI values are associated to three metals as Pb, cd and mainly Cr with particularly high concentrations. The present study as highlithed the carcigenic risks for inhabitants who consume oysters collected From Fresco Lagoon waters. These results demonstrate the need to control the quality of fishery products from artisanal fishing, such as oysters, for consumer’s protection.
