| Summary: | Juvenile (120-day) three fish species viz. Catla catla, Labeo rohita and Cirrhina mrigala were exposed to chronic sub-lethal concentrations (1/3rd 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 (29oC), 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.
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