Integration of sequential extraction, chemical analysis and statistical tools for the availability risk assessment of heavy metals in sludge amended soils. (August 2020)

• Record Type: Journal Article
• Authors: Khadhar, Samia; Sdiri, Ali; Chekirben, Anis; Azouzi, Rim; Charef, Abdelkarim
• Is Part Of: Environmental pollution. Volume 263(2020)Supplement Part B
• Publication Date: 2020-08
• Subjects: Sludge -- Amended soil depth -- Bureau commun reference -- Heavy metals -- Statical analysis; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2020.114543
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: This work has been conducted as an integrated approach to study the behavior of soils to the metals from sludge amendment. Bureau Commun Reference (BCR) methodology was used as an appropriate tool to harvest precious information about heavy metals evolution versus depth before and after sludge treatments. This three-step extraction procedure (i.e., BCR) may clarify the leaching or retention of heavy metals from the amended soils, as well as their risk level. Our results indicated that sludge applications has shown an increasing flux of heavy metals towards amended soils, of which Pb was the most abundant. Heavy metals mobility in control and amended soils showed that main influencing factors are pH and total organic carbon, especially for copper mobility. Almost all of the metals decreased with soil depth, except for Ni. Speciation of heavy metals in sludges showed that about 45% of Pb, Cu and Ni were associated with residual fraction; Cd was mainly bound to reducible fraction. Speciation forms in the control soil indicated that short term application of sludge has remobilized a fraction of heavy metals into their most labile forms (i.e., exchangeable and reducible fraction). Multivariate statistical analysis suggested that Cd, Zn, Pb and Cu preferentially accumulated in organic-rich surface horizons and clay layers where adsorption played an important role as a determining mechanism. Nevertheless, adsorption did not appear to be directly controlled by high pH values (pH > 7). From Cluster Analysis (CA), one can easily recognize that Pb, Zn and Cu movement in soil profiles were significantly affected by pH, especially residual fraction, labile fraction and reducible fraction. Graphical abstract: Image 1 Highlights: A modified BCR sequential extraction was applied for Tunisian sludge amended soils. Heavy metals pollution in soil was mainly controlled by pH and TOC of sludge. Short term application of sludge enhanced soil fertility. Heavy metals transfer between the soil compartments was proved by speciation.