<p>Phosphogypsum (PG), a by-product of phosphoric acid production, has shown potential as a soil amendment for saline and sodic soils due to its&#xa0;capacity&#xa0;to&#xa0;enhance&#xa0;soil structure, reduce salinity, and supply essential nutrients&#xa0;(calcium, sulfur, phosphorus…). However, concerns persist regarding the presence of potentially toxic elements (PTEs) and their potential environmental and health impacts. This study&#xa0;assessed&#xa0;the effects of Tunisian PG, applied at three rates (10, 20, and 40 t/ha), alone and combined with organic manure, on the mobility of PTEs in saline soils from an agricultural area in central-western Tunisia. Soil column leaching experiments were&#xa0;also&#xa0;conducted to simulate field conditions and&#xa0;evaluate&#xa0;changes in PTEs concentrations in both soil and leachate. The physicochemical and mineralogical properties of PG were characterized to evaluate its suitability. Results showed that PG application improved soil electrical conductivity (EC) and pH stability; the addition of manure enhanced organic matter (OM) content and reduced the mobility of certain PTEs, particularly cadmium (Cd) chromium (Cr) and lead (Pb). While copper (Cu), zinc (Zn), nickel (Ni), and iron (Fe) remained within acceptable thresholds, elevated levels of Cd, Cr, and Pb were observed at the highest PG dose. Leachate analysis revealed decreasing EC and stable pH values within WHO limits, along with PTEs specific leaching trends. Pollution indices and health risk assessments highlighted increased contamination risk at higher PG doses. Overall, the combined use of PG and manure appears to be a viable approach for saline soil remediation, provided that application rates are carefully controlled to minimize environmental risks.</p>

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Mobility and environmental risk of potentially toxic elements (PTEs) in phosphogypsum-amended saline soils: an integrated soil–leachate assessment

  • Wiem Mezlini,
  • Carlo Limonti,
  • Alessio Siciliano,
  • Rim Ben Amor

摘要

Phosphogypsum (PG), a by-product of phosphoric acid production, has shown potential as a soil amendment for saline and sodic soils due to its capacity to enhance soil structure, reduce salinity, and supply essential nutrients (calcium, sulfur, phosphorus…). However, concerns persist regarding the presence of potentially toxic elements (PTEs) and their potential environmental and health impacts. This study assessed the effects of Tunisian PG, applied at three rates (10, 20, and 40 t/ha), alone and combined with organic manure, on the mobility of PTEs in saline soils from an agricultural area in central-western Tunisia. Soil column leaching experiments were also conducted to simulate field conditions and evaluate changes in PTEs concentrations in both soil and leachate. The physicochemical and mineralogical properties of PG were characterized to evaluate its suitability. Results showed that PG application improved soil electrical conductivity (EC) and pH stability; the addition of manure enhanced organic matter (OM) content and reduced the mobility of certain PTEs, particularly cadmium (Cd) chromium (Cr) and lead (Pb). While copper (Cu), zinc (Zn), nickel (Ni), and iron (Fe) remained within acceptable thresholds, elevated levels of Cd, Cr, and Pb were observed at the highest PG dose. Leachate analysis revealed decreasing EC and stable pH values within WHO limits, along with PTEs specific leaching trends. Pollution indices and health risk assessments highlighted increased contamination risk at higher PG doses. Overall, the combined use of PG and manure appears to be a viable approach for saline soil remediation, provided that application rates are carefully controlled to minimize environmental risks.