Environmental Engineering Reference
In-Depth Information
Superoxide Dismutase-, Catalase- and Metallothionein Response
There were no significant differences in liver enzymatic activity measured as SOD
and CAT or concentration of MT between the various exposure regimes (Fig.
1
).
However, as for glucose in blood, dissolved Cu showed a significant positive rela-
tionship with SOD inhibition activity, indicating the presence of reactive oxygen
species (ROS) (Fig.
2
). Cu, together with Fe, are known to be inducers for free
oxygen radicals
[11, 27, 28]
and both were found in elevated concentrations in gill
tissue from fish exposed to the pond inlet (PI) water. Free radicals and formation of
ROS can bring about a series of responses in exposed organisms, such as changing
gene regulation or expression, stimulating DNA-repair mechanisms, impacting on
cell apoptosis, as well as interacting with important biomolecules such as enzymes
and proteins
[29, 30]
. This indicates that gill accumulated Cu and other metals
could induce free radicals and thereby disrupt cellular functions like Na/K-ATPase
[31]
in gills
[32]
.
Conclusions
The present study has showed that highway runoffs, even during low concentration
episodes, have the potential to disturb normal homeostasis in brown trout. We reg-
istered that several metals in the water heavily affected by road salt was mobilized
and present as dissolved metal species. This is probably the underlying mechanisms
for the elevated concentrations of metals in gill tissue from the trout exposed to
untreated (PI) and treated water (PO). Following the accumulation of metals in the
gill tissue, biological responses could also be expected. Therefore, the observed
loss of chloride ions in the blood plasma together with increased values of glucose
and pCO
2
is attributed to the accumulation of gill-reactive metal species produced
in the highway runoff.
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