Rapid Test Methods for the Field Screening of Heavy Metals in Soil Samples

Abstract

In the present work, rapid test methods for field screening of soil for Cu, Ni, and Pb content are presented. They are based on commercially obtainable Microquant tests (Merck, Germany), which are originally developed for water analysis. The same type of color reaction was also used for the determination of heavy metals in soil extracts: Reagents to form colored metal complexes are cuprizone for Cu, dimethylglyoxime for Ni, and dithizone for Pb. The experimental conditions for the colorimetric determination of these metals in the soil extracts were studied and additionally modified. An aqua regia solution (HCl/HNO 3 , 3:1) was used for the rapid extraction of metals from soil. To establish accuracy, results obtained with the proposed test methods were compared with those obtained with the standard laboratory method using microwave digestion and flame atomic absorption spectrometry (FAAS). Real soil samples containing metals at background levels generally yielded approximately 50% of the total content obtained with the standard FAAS method. High recovery values of spiked samples confirm that the colorimetric methods are unaffected by soil matrix effects.

Synthesis and Characterization of Slow-Release Chitosan Oligosaccharide Pyridine Schiff Base Copper Complexes with Antifungal Activity

“…Slow-Release Performance. The slow-release performance of CPSx-Cu complexes was evaluated in different pH environments using the BCO colorimetric method with some modifications as described in the study by Jozic et al 40 A 0.625% (w/v) BCO solution was prepared by dissolving 7.5 g of cuprizone in a 60% (v/v) mixture of ethanol and water and heating at 60 °C for 10 min. A buffer solution of ammonium citrate−ammonium chloride was prepared by dissolving 90 g of ammonium citrate and 3 g of ammonium chloride in 300 mL of deionized water, and a sodium hydroxide (NaOH) solution was prepared by dissolving 19.5 g of NaOH in 300 mL of deionized water.…”

Proposal of a simple screening method for a rapid preliminary evaluation of “heavy metals” mobility in soils of contaminated sites

“…The proposal of a simple in-field screening method is based on the foregoing considerations, and in this work, a singlestep leaching test has been developed and studied in order to obtain a rapid evaluation of metals mobility in polluted soils, mainly focused on the fraction associated to Fe and Mn oxide/hydroxides more dependent on the pH and oxidising variation in the soil environment (Alloway 2005) and, qualitatively and quantitatively, more representative of the risks related to HM mobility. The proposed method is less complex and more specific, in terms of soil fraction analysed, than other existing in-field screening systems such as the rapid test proposed by Jozic et al (2009), which, moreover, involves reagents that create safety problems when used for in-field analysis.…”