Use of C-18 reverse-phase cartridges for estimation of metal complexation by a residue from olive oil industry

 Formation of complexes between Cu and organic polymers present in olive mill wastewater (OMW) is shown to be a cause of metal solubilization by the residue, using C-18 reverse-phase cartridges (RPC) for separating the complexed metal. Nearly 100% of the metal released from a polluted river sediment by OMW solutions is retained by the cartridges. The proportion of Cu retained by the cartridges is somewhat lower (50–80%), if the OMW solution initially contains Cu. About 70–80% of Cu released by OMW from a soil column previously loaded with high doses of metal is also retained by the cartridges. Incomplete Cu retentions are not thought to be due to a lack of efficiency of RPC in immobilizing Cu complexes, but to the formation of an equilibrium between free and complexed forms of the metal. Received: 3 June 1996/Revised: 29 September 1996/Accepted: 10 October 1996