Lead Retention by Soils at Field Moisture Contents

Rao, Sudhakar M and Gaurave, Kumar and Sarvanan, Ayyavoo (2013) Lead Retention by Soils at Field Moisture Contents. In: SOIL & SEDIMENT CONTAMINATION, 22 (2). pp. 208-222.

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Abstract

The majority of studies pertaining to lead retention by clays and soils have examined the mechanisms, kinetics, and adsorption isotherms using the batch experiment technique that employs solid: water extracts of 1:10 and 1:20. Field soil deposits generally have much lower gravimetric water content ranging between 9 and 45%. Given the wide disparity in the solids: water ratio employed in the batch experiment technique and that prevailing in field deposits, this paper examines the lead retention characteristics of soils at field moisture contents (6%, 13%, and 25%) using artificially lead-contaminated soil specimens. A residually derived (i.e., formed by in-situ weathering of parent rock) red soil was used to prepare the artificially contaminated soil specimens. The impact of variations in clay content on lead retention was examined by diluting the residual soil with various amounts (0 to 60%) of river sand. Soil specimens remolded at 6 and 13% moisture contents produced very stiff to hard soils on compaction, while specimens remolded at 25% moisture content existed in the slurry state. The soil specimens were contaminated with low (30mg/kg) to high (2500mg/kg) concentrations of lead ions by remolding them with 160ppm to 10,000ppm ionic lead solutions. Lead retention by soils at field moisture contents was determined by extracting the lead from the soil using a water leach test. Experimental results showed that the bulk (71 to 99%) of the added lead was retained by the soil in insoluble form at the field moisture content. Correlations between the amount of lead retained and soil/solution parameters indicated that the amounts of Pb retained at field moisture content is a function of the initial Pb addition, total sand content, effective clay porosity, and soil pH.

Item Type:	Journal Article
Publication:	SOIL & SEDIMENT CONTAMINATION
Publisher:	TAYLOR & FRANCIS INC
Additional Information:	Copyright for this article belongs to TAYLOR & FRANCIS INC, USA
Keywords:	Lead;chemistry;moisture content;retention;soils
Department/Centre:	Division of Mechanical Sciences > Civil Engineering
Date Deposited:	15 Feb 2013 12:08
Last Modified:	15 Feb 2013 12:08
URI:	http://eprints.iisc.ac.in/id/eprint/45780

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