The uptake of zinc, lead, copper and manganese by carp fed with activated sludge.

The incorporation of 10 or 40% of activated sludge improved the growth rates of common carp, Cyprinus carpio, by comparison with those receiving a commercial fish feed (Tubifex worms) alone. The incorporation of 70% or 85% sludge, however, yielded very poor growth rates. The visceral organs of fish receiving 70 or 85% sludge contained 2 X zinc (Zn), 2.5 X copper (Cu) and 1.4 X manganese (Mn) of the control group.