Bioaccumulation of Hexavalent Chromium in Tissues of a Freshwater Fish

This study aims to investigate the bioaccumulation Tissues. The experiment was carried on for 28 days, meanwhile sampling fish weekly. With continued exposure, the accumulations were increased and fish progressively lost their ability to respond to this increase in exposure period. The control group displayed normal behavior during the test period. The lowest concentrations (10 and 15 mg/L Cr6+) had similar behavior to that of the control group. From the dose 20 mg/ L Cr6+, the fish started to show behavioral disorders. 25 mg/L Cr6+ and at the highest concentration (30 mg/L Cr6+) onwards, there was shivering, rather high respiratory disorder and swimming in capsized position in the following order the concentrations of Cr in gills were almost twice, three and four times as high as in the muscle at 20, 25 and 30 ug/L Cr6+ mediums, respectively. The Cr accumulation on the skin of Tilapia for all experimental concentrations was nearly twice as much as in the muscle of samples at the end of experiment.