Agriculture Reference
In-Depth Information
8
Bioindicators and Biomarkers in the
Assessment of Soil Toxicity
Carmem Silvia Fontanetti, Larissa Rosa Nogarol, Raphael Bastão de Souza,
Danielli Giuliano Perez and Guilherme Thiago Maziviero
Department of Biology, Institute of Biosciences, São Paulo State University (UNESP)
Rio Claro, SP,
Brazil
1. Introduction
Several potentially harmful chemical compounds, derived from activities of urban centres,
rural properties and industries are constantly released into the terrestrial environment. In
this context, the scientific community has shown increasing interest in the detection,
knowledge and control of environmental agents responsible for damages to human health
and sustainability of ecosystems (Magalhães & Ferrão-Filho, 2008).
Monitoring the types and quantities of toxic substances that are entering into the terrestrial
environment is an exhaustive and problematic task due, mainly, to the complexity and cost
resulting from the identification of the chemical substances involved. Despite the numerous
analytical methods available, collecting sufficient samples in a timely fashion continues to be
a great obstacle in the evaluation of environmental damages (Silva et al., 2003).
Furthermore, the determination of isolated substances by traditional chemical analyses has a
limited environmental application, since it does not detect the effects on the organisms
neither inform about the possible interactions between the substances (additive, antagonistic
or synergistic), as well as their bioavailability (Magalhães & Ferrão-Filho, 2008). In this
sense, researchers have pointed the necessity to apply biological methodologies in order to
obtain an ecosystemic approach.
Biological factors may indicate better the environmental balance through the biotic indexes,
derived from the observation of bioindicator species. According to Hodkinson and Jackson
(2005), it is called bioindicator a species or group of species that reflects biotic and abiotic
levels of contamination of an environment, presenting alterations that enables the
generation of information about the quality of the environment, for example, accumulating
substances in concentrations higher than those considered normal or essential for its body
metabolism or presenting alterations in the number of organisms. Such organisms, due to
their characteristics of little ecological tolerance to some chemical substances, can present
some alteration, whether it is physiological, morphological of behavioural, when exposed to
certain pollutants (Magalhães & Ferrão-Filho, 2008).
Due to their close contact with soil, some taxonomic groups of invertebrates belonging to the
meso- and macro-fauna such as, Isopoda, Collembola, Oligochaeta and Diplopoda, have
been proposed as bioindicator organisms (Hopkin, 2002). In addition, higher plants such as
Allium cepa (onion), Arabidopsis thaliana (mustard), Hordeum vulgare (barley), Tradescantia sp. ,
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