Tissue-specific Bio-accumulation of Metals in Fish during Chronic
Waterborne and Dietary Exposures
M.
Javed
Department of Zoology & Fisheries, University of Agriculture,
Faisalabad, Pakistan
Corresponding author: javeddr1@hotmail.com
Abstract
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 Cirrhina mrigala (31.43±13.70 µg g-1) exhibited
significantly higher ability to amass metals than that of Catla 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.