Neapolitan yellow tuff for the recovery of soils polluted by potential toxic elements in illegal dumps of Campania Region

The Neapolitan yellow tuff (NYT) was utilized as a component of an organo-mineral sorbent/exchanger soil conditioner with pellet manure (NYT/PM) to limit the mobility of Cd and Pb in heavily polluted soils from illegal dumps in Low Volturno river basin (Campania Region, southern Italy). The NYT/PM mixture (1:1, w/w) was added to soil at the rates of 0%, 25%, 50% or 75% (w/w). The overall significant effect of the amendment with NYT/PM on soil properties was the substantial reduction of the availability of the toxic elements, with special reference to Pb, connected with an increase of cation exchange capacity and electrical conductivity and a moderate decrease of soil pH. The observed effects were primarily ascribed to the Pb-selectivity of phillipsite and chabazite present in the tuff matrix. On the whole, our findings suggest the suitability of NYT as natural exchanger material to be utilized in strategies for the remediation of polluted sites.