APPLICATION OF MULTI-METAL BIOACCUMULATION INDEX AND BIOAVAILABILITY OF HEAVY METALS IN Unio sp. (UNIONIDAE) COLLECTED FROM TERSAKAN RIVER, MUGLA, SOUTH-WEST TURKEY

In the present study, some heavy metals (Cd, Co, Cr, Cu, Fe, Mn, N, Pb and Zn) were seasonally determined in some tissues of mussel Unio sp. from Tersakan River, which is an important agricultural, a visiting area and, a water source for irrigation. Generally, higher concentrations of the measured metals were found in the winter and autumn compared with those during spring and summer. High levels of heavy metals were found in shell samples, while low levels in muscle. The measured metal concentrations in tissues is not differed significantly for all metals except Fe between autumn and spring but significant differences for Cd, Co, Cr, Cu, Mn and Pb were observed between summer and aututnn (p<0.0.5). Individual Multi-Metal Bioaccumulation Index (MBI) values varied from 0.01 to 0.44, 0.00 to 0.47, and 0.00 to 0.43 in muscle, gill, and shell respectively. Generally, IMBI values calculated in muscle were higher than gill and shell. According to the acceptable values for human consumption designated by various health organizations, concentrations of some metals such as Cd and Pb were more than the designated limits, especially in summer.