Tissue-specific Bio-accumulation of Metals in Fish during Chronic Waterborne and Dietary Exposures

Juvenile (120-day) three fish species viz. catla catla, labeo rohita and cirrhina mrigala were exposed to chronic sub-lethal concentrations (1/3^rd of lc50/ld50) of waterborne and dietary copper (cu), cadmium (cd), zinc (zn), nickel (ni) and cobalt (co), separately, in glass aquaria under constant water temperature (29°c), ph (7.5) and hardness (225 mgl^-1) for 12 weeks. waterborne and dietary exposures caused significantly variable accumulation of metals in three fish species that followed zn>ni>cd>co>cu. fish liver showed significantly higher tendency to accumulate cu (69.64±25.35 μg g^-1), cd (68.93±21.65 μg g^-1), zn (91.46±29.53 μg g^-1), ni (74.64±18.61 μg g^-1) and co (22.65±20.56 μg g^-1), followed by that of kidney and gills, with significant differences while muscle and bones exhibited significantly least tendency to accumulate all metals. labeo rohita (31.63±2.43 μg g^-1) and c. mrigala (31.43±13.70 μg g^-1) exhibited significantly higher ability to amass metals than that of c. catla (27.96±10.28 μg g^-1). waterborne exposure caused significantly higher accumulation of metals in fish liver (72.69±27.91 μg g^- 1), followed by that in kidney, gills, skin, muscle, fins and bones with the average concentrations of 45.14±18.70, 39.47±21.13, 30.81±12.64, 22.65±17.34, 22.23±11.74 and 12.14±6.25 μg g^-1, respectively. dietary exposure resulted into significant escalation of metals in fish liver (58.23±32.44 μg g^-1) while it was lowest in bones. waterborne exposure caused significantly higher accumulation of all metals in fish body than that of dietary treatments.