RESUMO
Laboratory experiments were conducted at different salinities (35, 26 and 17/1000) to determine accumulation and depuration rates of the organochlorine compound aldrin by the oyster Crassostrea rhizophorae, Ciénaga Grande de Santa Marta (Colombian Caribbean). Residual levels were detected in tissues after 24 hours of exposure, showing increases directly related to the exposure concentration. For all the exposure concentrations the highest retention values were measured at 26/1000 salinities, followed by 17/1000, and the lowest values at the highest salinity. The highest bioconcentration values were 96115.5 (at 26/1000), 37938.9 (at 17/1000), and 22605.1, (35/1000) times the environmental concentration. The depuration process varied across salinity levels. At 26/1000 there was a clear decrease in the residual levels during the first five days, eliminating in this period the same amount as oysters kept at 17/1000 for 20 days and surpassing the amount eliminated by those kept at 35/1000 for 20 days. A rapid decrease in the amount of residues is followed by a slow elimination of the aldrin remaining in tissues