Marine Ecosystems under Toxic Pressure - Vulnerability of Coastal Ecosystems and Adaptation - page 14

or integument) that is involved in the organism's contamination
kinetics.
1.3.2.2. How specific variability and individual influence the
depuration rate
The biological and ecological characteristics of species and
individuals are also involved in their capacity to eliminate or store the
contaminant in a non-dangerous form. Passive elimination of the
compound implies its excretion or accumulation in inert compartments
of the organism [GRO 99]. Furthermore, tissues with a high lipid
content offer a significant storage volume of hydrophobic
contaminants. Differences in the presence and volume of these
compartments generate a strong interspecies variability in biological
response to toxins and, in particular, to organic products [ESC 02].
These differences are linked to the relative size of species: in effect, it
is generally the largest organisms that possess the most lipidic
reserves [CAN 02, ESC 02].
Thus, it is mainly the characteristics linked to use of the habitat and
food, as much as the characteristics linked to the pattern of the
organisms' life history, which determines their response to
contaminants at an individual level.
1.3.2.3. Some types of toxic effects
Certain pollutants, characterized as “endocrine disruptors” (PE),
act on organisms' hormonal equilibrium. Endocrine disruptors are
exogenous substances that trigger effects harmful to the health of an
organism or its descendents, following changes to endocrine function.
The action mechanisms of PEs are multiple, since they can act on all
the stages of endocrine regulation, from the synthesis of hormones to
activity at the level of the target tissues. Among aquatic organisms,
exposure to PEs has been associated with harmful effects on the
reproduction (Figure 1.4; [CRA 08, DAO 11, MEN 08, MIL 05]) of
individuals and populations. Certain pollutants have also been
identified as neurotoxic, leading to effects on the neural functions of
fish, and they can, therefore, potentially affect the species's behavior
and learning [PEA 13].