metals bioaccumulation in five organs of cirrhinus  mrigala , labeo  rohita and catla catla captured from three industrial and sewage polluted downstream sites (shahdera = b, sunder = c and balloki = d) were compared with a non-industrial upstream site (siphon = a) during high (post monsoon) and low (winter) flow seasons of river ravi. mean concentrations of metals were significantly higher in ...