| Abstract | The toxicity and bioavailability of metals were assessed to verify the efficiency of a new chemical leaching process (METIX-AC) to minimizethe risk of metals found in municipal sewage sludge. For this purpose, sludge samples were spiked with cadmium, copper and/or zincbefore being treated using METIX-AC. The sludge decontamination resulted in a removal of spiked metals (79e89%), in a decrease of themore labile fractions, and in a corresponding increase of the residual fraction. The toxicity observed after exposure of two plant species, barley(Hordeum vulgare) and ryegrass (Lolium perenne), and a terrestrial invertebrate, Eisenia andrei, to sludge-soil mixtures, disappeared after treatment, although the adverse effects were minor before treatment. The sludge treatment also significantly decreased the bioaccumulation of cadmium, copper, and zinc in the exposed species. For cadmium, maximum tissue concentrations of 0.45 0.08 mg/kg in barley, 0.79 0.27 mg/kg in ryegrass, and 21.82 1.85 mg/kg in earthworm exposed to sludge before treatment decreased after treatment to values similar to thoseobserved with negative controls. |
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