Journal of Laboratory Chemical Education 2014, 2(1): 4-9
DOI: 10.5923/j.jlce.20140201.02
Developing an Environmental Analysis of Soils and Water
by Spectrochemical Techniques for Undergraduate
Students of Chemistry
Jesús Anzano
*
, LeyreAbia, Minerva Aragonés, Elena Ballano, Beatriz Guzmán,
Mª Luisa Lomero, Catalina Pena, Elisa Pérez
Laser laboratory, Department of Analytical Chemistry, Faculty of Sciences, University of Zaragoza, Pedro Cerbuna #12, 50009, Zaragoza,
Spain
Abstract Quantification of heavy metals (Cr, Cu, Zn, K, Ca, Fe and Mn) in water and soils samples was performed
through atomic and molecular spectrometry. The validity of three leaching agents (ethylenediaminetetraacetic acid, acetic
acid and deionized water) was compared in soil samples to potassium, calcium, iron and manganese by means of atomic
spectrometry. Acetic acid was the best leaching agent for all metals except for iron, and EDTA was the second best. Two
experiments were developed for water samples. First, precipitation was used to separate toxic metals and, secondly, the
speciation of Cr (III) and Cr (VI) was carried out using diphenylcarbazide and ethylenediaminetetraacetic acid to set up
complexes selectively. It was proved that the removal of Cr, Cu and Zn by precipitation of the hydroxide was effective
obtaining low ranks.
Keywords Atomic and Molecular Spectroscopy, Determination, Potassium, Calcium, Iron, Manganese, Chrome,
Cupper, Zinc, Soil, Water
1. Introduction
Nowadays, the presence of heavy metals in the
environment is a very interesting issue, due to their
persistence in soils and waters[1]. Considerable amounts of
polluting metals are accumulated yearly. Soil and water are
among the valuable common properties societies try to
preserve the most, but they can be polluted by household,
industrial or farming wastes. Heavy metals are among the
polluting substances, usually coming from industrial
processes such as paint production or chroming[2].
From a chemical point of view, heavy metals contain
elements known as transition and post-transition. Those
elements are significantly heavier than light metals like K or
Na. Some of them are animal and plant nutrients but they are
toxic in high concentrations. For example, trivalent
chromium is an essential oligoelement and its deficiency
causes diabetes and other adverse effects in the body.
However, hexavalent chromium is extremely toxic, as it
causes allergy, breath and liver deficiency, mutations and
cancer[3]. Because of these harmful effects in the long and
short-term, maximum admissible concentrations of the
* Corresponding author:
janzano@unizar.es (Jesús Anzano)
Published online at http://journal.sapub.org/jlce
Copyright © 2014 Scientific & Academic Publishing. All Rights Reserved
seions in drinking water, publicor industrial discharges must
be regulated by the applicable laws. Toxic concentration
limits are different to each metal and depend on the kind of
ion and its physiological and environmental effects.
European law (Directive 98/83/CE, 3 of November of
1998, relating to drinking water quality published in DOCE
L Nº 330, 5 of December of 1998) fix chromium (0.05 mg/L)
and cupper limits (2 mg/L) in drinking water. Zinc does not
have risk level in water but World Health Organization lay
down 5 mg/L as a legal limit. On the other hand, law
22/2011 (28 of July, of wastes and contaminated soils) and
law 1/2005 (4 of February, of prevention and correction to
soils contamination) regulate contaminated agents in soils[4,
5].
Analytic techniques for metal analysis in soils and water
samples are varied; their election depends on the metal
concentration grade and its nature. Usual techniques are:
Flame Atomic Absorption Spectrometry (AAS-Flame),
Graphite Furnace Atomic Absorption Spectrometry
(GFAAS), Inductively Coupled Plasma - Atomic Emission
Spectrometer (ICP-AES), Inductively Coupled Plasma-Mass
Spectrometry (ICP-MS). Multielement analysis and
automatic techniques result particularly useful because they
generate big data series and they need minimum effort and
time[6].
This article contains two different parts: metal
determination in soils and in water. In our case, we search