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Author(s): M E Conti
Abstract:
ers for environmental monitoring
M E Conti
1 Introduction:
Many researches about toxicology, especially aquatic toxicology, have focused
extensively on the early phases of the impact of a contaminant with an organism,
characterized by its interaction with the endogenous molecules.
Fig.
1 reports a
synthesis of the interactions between the contaminants present in the aquatic
ecosystem and their biological effects.
Toxicology evaluations do not have recourse to biological indicators in the
strict sense of the term.
In the field of toxicology, there are very interesting
prospects for biomarkers, which are specific biochemical, genetic, morphological
or physiological changes measurable in each organism and which are associated
with particular stress situations (for instance, in the presence of heavy metals,
pesticides, etc.).
Biomarkers signal the occurrence of toxicological events much
earlier than the emergence of those effects that can be measured in biocoenosis at
the population level.
The measurements of the biological effect ensuing exposure
to contaminants follow two main criteria [1–4]:
1.
The biological change must be caused exclusively by the contaminant.
The evaluation
must also takes into account the variables those are present all the time
(for instance, season, gender, temperature) so as to establish a good signal/noise
ratio.
2.
It must also be correlated with a negative effect on some physiological aspects of
the organism under study, such as growth, reproduction or survival.
In particular,
response times must be short, within the range of hours–weeks.
Depledge [5] proposed a more exhaustive definition of biomarkers.
A biomarker
is defined as a change at a biochemical, cellular, physiological or behavioural
level; it can be measured in tissues and/or cellular fluids and/or in the whole
organism and shows the exposure and/or the effects of one or more chemical
contaminants (and/or radiations).
As briefly hinted above, the principal characteristic of biomarkers is the
fact that they signal change events (also with localized toxicity effects) long
before the appearance of measurable effects in the biocoenosis at the population
level.
...
Pages: 22
Size: 1,231 kb
Paper DOI: 10.2495/978-1-84564-002-6/02
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