Stabilisation of metals in mine spoil with amendments and growth of red fescue in symbiosis with mycorrhizal fungi

Abstract

Metal stabilisation effects of amendments (1% m/m CaCO<sub>3</sub>-L, 5% m/m municipal sewage sludge compost-MSSC, and 7.5% m/m natural zeolite-Z) were studied on acidic mine spoil (pH<sub>KCl</sub> 3.73) from Gyöngyösoroszi (Hungary) containing Cd-15.0, Cu-336, Mn-568, Pb-1919, and Zn-3306 mg/kg. Red fescue (Festuca rubra, cv. Keszthelyi 2) was grown in a pot experiment in amended mine spoil, and was infected with spores of a Zn-tolerant arbuscular mycorrhizal fungi (AMF) Glomus intraradices. During 12 weeks of plant growth L + MSSC + Z amendments were more effective in stabilizing the pH, reducing the leaching and phytoavailability of metals in mine spoil than the lime application itself. Liming (L) had a negative effect on Cd, Mn and Zn concentrations in mine spoil water (leachate) as compared to the untreated control. In mine spoil stabilized with a combination of amendments red fescue growth can be established in symbiosis with AMF. Rate of AMF infection (F 4%) was low in limed mine spoil but was especially high (F 93%) in the case of L + MSSC + Z application. In shoots of these cultures − as a trend − AMF reduced the concentration of Cd by 35–55%, Cu by 9–34%, Mn by 14–55%, and Zn by 22–44%.