Immobilization of lead and cadmium in a calcareous soil, bio-accumulation in maize (Zea mays L.) and potential environmental risk as affected by amendments

• Published in: Environmental earth sciences Vol. 83; no. 13; p. 395
• Main Authors: Shahkolaie, Somayeh Sefidgar, Baranimotlagh, Mojtaba, Khodaverdiloo, Habib, Khormali, Farhad, Dordipour, Esmael
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.07.2024; Springer Nature B.V
• Subjects: Accumulation; Bentonite; Bioavailability; Biogeosciences; Cadmium; Calcareous soils; Charcoal; Contamination; Corn; Earth and Environmental Science; Earth Sciences; Ecological risk assessment; Environmental risk; Environmental Science and Engineering; Geochemistry; Geology; Heavy metals; Hydrology/Water Resources; Immobilization; Lead; Mining; Original Article; Pumice; Rice straw; Risk assessment; Shoots; Soil; Soil amendment; Speciation; Terrestrial Pollution; Zea mays; Zeolites; Environmental risk assessment; Amendment; Bioavailability; Speciation; Heavy metals
• ISSN: 1866-6280; 1866-6299
• DOI: 10.1007/s12665-024-11694-z

Mining activities are among the main sources of heavy metal contamination in the environment. The damage caused to land by mining has become an increasingly important problem in some countries. A pot experiment was conducted to evaluate the effects of two application rates (1% and 5% w/w) of rice straw biochars, as prepared at 420 ∘ C and 640 ∘ C (B1420 and B640), and several inorganic amendments (pumice, leca, zeolite and bentonite) on Cd and Pb bioavailability and speciation in soil and their accumulation in maize ( Zea mays L.) as an indicator plant. Furthermore, the amelioration effects of the applied amendments on the potential environmental risk of the heavy metals were assessed. The amendments resulted in a considerable reduction of the Cd and Pb contents in the shoots, which was by 28.83–70.72% and 21.78–64.02%, respectively, as compared to the control. Amendments also decreased the DTPA-extractable Pb and Cd in the soil, particularly at the 5% application rate, as compared to those in the un-amended soil. Furthermore, in comparison to the control, the transfer factors of heavy metals were reduced when the amendments were applied. Amendments also decreased the exchangeable portion of Cd and Pb by 10.43–52.11% and by 6.43–55.43%, respectively; most of these were converted into oxides and more stable forms exhibiting the lower risk assessment code (RAC) and the potential ecological risk index (PERI). These results indicate that zeolite and BI420 have a high potential to decrease the uptake of Cd and Pb in the shoots and roots of maize, respectively. Biochar and zeolite, as cost-effective and safe adsorbents, performed the best in immobilizing Pb and Cd in the studied calcareous soil.