Apparent bioaccumulation of Mn derived from paper-mill effluent by the freshwater crayfish Cherax destructor — the role of Mn oxidising bacteria

Bioaccumulation studies of wastewater from a thermo-mechanical paper mill using the freshwater crayfish (Cherax destructor) consistently demonstrated elevated levels of manganese. Most of the Mn appeared to be associated with the carapace of the animals. It is suggested that the elevated Mn levels are the result of Mn-oxidising bacteria forming biofilms on the carapace of the crayfish followed by Mn oxide precipitation rather than active uptake of Mn by the crayfish.