A. Xenidis et al., The effectiveness of municipal sewage sludge application on the stabilization of Pb, Zn, and Cd in a soil contaminated from mining activities, J ENVIR S A, 36(6), 2001, pp. 971-986
Citations number
26
Categorie Soggetti
Environment/Ecology
Journal title
JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART A-TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING
The effectiveness of municipal sewage sludge for the stabilisation of Pb, Z
n and Cd in a heavily contaminated soil was evaluated by performing pot exp
eriments on soil-sludge mixtures. The soil sample originated from the Monte
vecchio mining district, Sardinia, Italy, and presented high Pb, Zn and Cd
content, as well as US EPA TCLP solubility values for Pb and Cd, which exce
eded the respective regulatory limits. Sewage sludge application increased
the soil pH. Stabilisation experiments showed that 10% w/w sewage sludge ad
dition effectively reduced Pb and Cd solubilities below the TCLP regulatory
limits. At the same addition rate, the EDTA extractable fraction of Pb, Zn
, Cd in the treated soil was reduced by 12, 47 and 50% respectively compare
d with the untreated sample. The five-stage sequential extraction procedure
applied on the untreated and treated soil samples, showed a remarkable shi
ft of the metals towards more stable forms. The reducible fractions of Zn a
nd Cd and the residual fraction of Pb were increased by 12, 20 and 18% resp
ectively, while a corresponding decrease in the mobile fractions (exchangea
ble and carbonate) occurred which accounted for 14, 23 and 25% respectively
.