Assessment of Extractants for the Determination of Thallium in an Accidentally Polluted Soil

Abstract

Thallium is a rare and easily dispersed element with high toxicity to organisms. Relatively high levels of thallium (approximately 9.58 mg kg(-1)) had been found in aqua regia soil extract of an accidentally polluted soil from south of Spain. To assess the available and leachable portions of thallium in the polluted soil, single and sequential extraction procedures have been utilized. Further, X-ray diffraction and scanning electron microscopic studies have also been used to find out the mineral phases. The amount of thallium extracted by the extracting agents in comparison to aqua regia, as well as the different phase associations are discussed.

Distributions and Concentrations of Thallium in Korean Soils Determined by Single and Sequential Extraction Procedures

“…However, DTPA-extractable thallium was extremely low compared with all of the other extractants even though this complexing reagent has been used as a powerful extractant for most other heavy metals including Cd, Cu, Fe, Mn, and Zn, after being introduced by Lindsay and Norwell (1978) (Lindsay and Norvell 1978) 3 Extractant for exchangeable fraction BCR sequential extraction method (Rauret et al 1999) 4 Extractant for exchangeable fraction of Tessier's sequential extraction method (Tessier et al 1979) to predict micronutrient deficiencies and to estimate metal availability for plants. Rao et al (2008) reported somewhat similar results with several single extractants from an accidently thallium-contaminated soil; the order of thallium extractability was 1.0 M HCl ) These results are basically in agreement with a report from Zbiral et al (2002). Higher thallium extractability with ammonium and potassium salts/acids compared with other common strong extractants might be related to the ionic radius (1.49 Å ) of thallium (Tl ?…”

“…Oxidizable/ organically bound fractions were highest in the SC soil that was higher soil organic matter content. Similar results of residual fractions making up the major part of thallium fractions in soils formed on floodplain terraces (Jakubowska et al 2007), in accidently polluted soils (Rao et al 2008), in river basin sediment (Liu et al 2010), and in sediment formed by a tsunami (Lukaszewski et al 2012), which ranged between 41.0 % and 96.9 %, have been reported. In addition, major labile forms of thallium in different materials were mostly reducible and/or oxidizable fractions.…”

Tracing Anthropogenic Thallium in Soil Using Stable Isotope Compositions

“…This conclusion is supported by the observation that the relatively mild 1 M NH 4 NO 3 extractant, which is used to leach the exchangeable fraction of elements, recovered only ≤2% of the total Tl budget for soil horizons deeper than 40 cm (with total [Tl] <0.3 mg kg −1 ), a value that is typical for uncontaminated soils. 41 The exchangeable Tl fraction increases to up to 17% (of total Tl) in topsoils from near the cement plant, suggesting that a highly mobile form of Tl was added to the soils (Table 1). The observed rise in the concentration of readily exchangeable Tl cannot, however, account for the overall increase of the total Tl content (compare Figures 2a and 2b).…”

Assessment of the BCR sequential extraction procedure for thallium fractionation using synthetic mineral mixtures

“…To our best knowledge, the standardized or optimized BCR (Community Bureau of Reference) sequential extraction (SE) is one of the most frequently used methods for predicting Tl fractionation in polluted soils and sediments [9][10][11][12]. However, the use of SE methods has been often criticized for the lack of selectiveness caused by possible redistribution and readsorption of some elements during the extraction procedure, inadequate efficiency of the extraction agents used or even absence of specific soil/sediment phases [7,13,14].…”