Leachability And Plant Availability Of Trace Elements In Pb/zn ‎mine Soil Treated With Different Amendments ‎

A multi metal polluted soil from Jebel Ressas mining area ‎‎(Southern of Tunisia) was treated with four cost-effective ‎amendments (CaCO3, phosphate rock, activated carbon, and ‎exhausted olive cake ash). Lixiviate from each treated and ‎untreated soil were analyzed, and ryegrass-seed bioassays ‎‎(Lolium perenne L.) were performed. The Cd, Pb and Zn leaching ‎was reduced by all amendments mainly due to alkalinity ‎increase. Phosphate rock addition to the soil reduced metal ‎concentration in plant tissue. Additionally, the activated carbon ‎amendment significantly decreased accumulation of Cd, Zn and ‎Pb in the plant studied. The results obtained in this study suggest ‎that the the addition of CaCO3 offered the best compromise as it ‎successfully reduced both the leaching and the phytoavailability ‎of the three considered metals.‎